chan_mgcp.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Implementation of Media Gateway Control Protocol
 *
 * \author Mark Spencer <markster@digium.com>
 *
 * \par See also
 * \arg \ref Config_mgcp
 * \arg \ref res_pktccops
 *
 * \ingroup channel_drivers
 */

/*** MODULEINFO
        <use type="module">res_pktccops</use>
   <support_level>extended</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 406038 $")

#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <fcntl.h>
#include <netdb.h>
#include <sys/signal.h>
#include <signal.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <ctype.h>

#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/sched.h"
#include "asterisk/io.h"
#include "asterisk/rtp_engine.h"
#include "asterisk/acl.h"
#include "asterisk/callerid.h"
#include "asterisk/cli.h"
#include "asterisk/say.h"
#include "asterisk/cdr.h"
#include "asterisk/astdb.h"
#include "asterisk/features.h"
#include "asterisk/app.h"
#include "asterisk/musiconhold.h"
#include "asterisk/utils.h"
#include "asterisk/netsock2.h"
#include "asterisk/causes.h"
#include "asterisk/dsp.h"
#include "asterisk/devicestate.h"
#include "asterisk/stringfields.h"
#include "asterisk/abstract_jb.h"
#include "asterisk/event.h"
#include "asterisk/chanvars.h"
#include "asterisk/pktccops.h"

/*
 * Define to work around buggy dlink MGCP phone firmware which
 * appears not to know that "rt" is part of the "G" package.
 */
/* #define DLINK_BUGGY_FIRMWARE  */

#define MGCPDUMPER
#define DEFAULT_EXPIRY  120
#define MAX_EXPIRY   3600
#define DIRECTMEDIA  1

#ifndef INADDR_NONE
#define INADDR_NONE (in_addr_t)(-1)
#endif

/*! Global jitterbuffer configuration - by default, jb is disabled
 *  \note Values shown here match the defaults shown in mgcp.conf.sample */
static struct ast_jb_conf default_jbconf =
{
   .flags = 0,
   .max_size = 200,
   .resync_threshold = 1000,
   .impl = "fixed",
   .target_extra = 40,
};
static struct ast_jb_conf global_jbconf;

static const char tdesc[] = "Media Gateway Control Protocol (MGCP)";
static const char config[] = "mgcp.conf";

#define MGCP_DTMF_RFC2833  (1 << 0)
#define MGCP_DTMF_INBAND   (1 << 1)
#define MGCP_DTMF_HYBRID   (1 << 2)

#define DEFAULT_MGCP_GW_PORT  2427 /*!< From RFC 2705 */
#define DEFAULT_MGCP_CA_PORT  2727 /*!< From RFC 2705 */
#define MGCP_MAX_PACKET    1500 /*!< Also from RFC 2543, should sub headers tho */
#define DEFAULT_RETRANS    1000 /*!< How frequently to retransmit */
#define MAX_RETRANS     5    /*!< Try only 5 times for retransmissions */

/*! MGCP rtp stream modes { */
#define MGCP_CX_SENDONLY   0
#define MGCP_CX_RECVONLY   1
#define MGCP_CX_SENDRECV   2
#define MGCP_CX_CONF    3
#define MGCP_CX_CONFERENCE 3
#define MGCP_CX_MUTE    4
#define MGCP_CX_INACTIVE   4
/*! } */

static const char * const mgcp_cxmodes[] = {
   "sendonly",
   "recvonly",
   "sendrecv",
   "confrnce",
   "inactive"
};

enum {
   MGCP_CMD_EPCF,
   MGCP_CMD_CRCX,
   MGCP_CMD_MDCX,
   MGCP_CMD_DLCX,
   MGCP_CMD_RQNT,
   MGCP_CMD_NTFY,
   MGCP_CMD_AUEP,
   MGCP_CMD_AUCX,
   MGCP_CMD_RSIP
};

static char context[AST_MAX_EXTENSION] = "default";

static char language[MAX_LANGUAGE] = "";
static char musicclass[MAX_MUSICCLASS] = "";
static char parkinglot[AST_MAX_CONTEXT];
static char cid_num[AST_MAX_EXTENSION] = "";
static char cid_name[AST_MAX_EXTENSION] = "";

static int dtmfmode = 0;
static int nat = 0;
static int ncs = 0;
static int pktcgatealloc = 0;
static int hangupongateremove = 0;

static ast_group_t cur_callergroup = 0;
static ast_group_t cur_pickupgroup = 0;

static struct {
   unsigned int tos;
   unsigned int tos_audio;
   unsigned int cos;
   unsigned int cos_audio;
} qos = { 0, 0, 0, 0 };

static int immediate = 0;

static int callwaiting = 0;

static int callreturn = 0;

static int slowsequence = 0;

static int threewaycalling = 0;

/*! This is for flashhook transfers */
static int transfer = 0;

static int cancallforward = 0;

static int singlepath = 0;

static int directmedia = DIRECTMEDIA;

static char accountcode[AST_MAX_ACCOUNT_CODE] = "";

static char mailbox[AST_MAX_EXTENSION];

static int amaflags = 0;

static int adsi = 0;

static unsigned int oseq_global = 0;
AST_MUTEX_DEFINE_STATIC(oseq_lock);

/*! Wait up to 16 seconds for first digit (FXO logic) */
static int firstdigittimeout = 16000;

/*! How long to wait for following digits (FXO logic) */
static int gendigittimeout = 8000;

/*! How long to wait for an extra digit, if there is an ambiguous match */
static int matchdigittimeout = 3000;

/*! Protect the monitoring thread, so only one process can kill or start it, and not
    when it's doing something critical. */
AST_MUTEX_DEFINE_STATIC(netlock);

AST_MUTEX_DEFINE_STATIC(monlock);

/*! This is the thread for the monitor which checks for input on the channels
 *  which are not currently in use.
 */
static pthread_t monitor_thread = AST_PTHREADT_NULL;

static int restart_monitor(void);

static struct ast_format_cap *global_capability;
static int nonCodecCapability = AST_RTP_DTMF;

static char ourhost[MAXHOSTNAMELEN];
static struct in_addr __ourip;
static int ourport;

static int mgcpdebug = 0;

static struct ast_sched_context *sched;
static struct io_context *io;
/*! The private structures of the mgcp channels are linked for
 * selecting outgoing channels
 */

#define MGCP_MAX_HEADERS   64
#define MGCP_MAX_LINES     64

struct mgcp_request {
   int len;
   char *verb;
   char *identifier;
   char *endpoint;
   char *version;
   int headers;         /*!< MGCP Headers */
   char *header[MGCP_MAX_HEADERS];
   int lines;        /*!< SDP Content */
   char *line[MGCP_MAX_LINES];
   char data[MGCP_MAX_PACKET];
   int cmd;                        /*!< int version of verb = command */
   unsigned int trid;              /*!< int version of identifier = transaction id */
   struct mgcp_request *next;      /*!< next in the queue */
};

/*! \brief mgcp_message: MGCP message for queuing up */
struct mgcp_message {
   struct mgcp_endpoint *owner_ep;
   struct mgcp_subchannel *owner_sub;
   int retrans;
   unsigned long expire;
   unsigned int seqno;
   int len;
   struct mgcp_message *next;
   char buf[0];
};

#define RESPONSE_TIMEOUT 30   /*!< in seconds */

struct mgcp_response {
   time_t whensent;
   int len;
   int seqno;
   struct mgcp_response *next;
   char buf[0];
};

#define MAX_SUBS 2

#define SUB_REAL 0
#define SUB_ALT  1

struct mgcp_subchannel {
   /*! subchannel magic string.
      Needed to prove that any subchannel pointer passed by asterisk
      really points to a valid subchannel memory area.
      Ugly.. But serves the purpose for the time being.
    */
#define MGCP_SUBCHANNEL_MAGIC "!978!"
   char magic[6];
   ast_mutex_t lock;
   int id;
   struct ast_channel *owner;
   struct mgcp_endpoint *parent;
   struct ast_rtp_instance *rtp;
   struct sockaddr_in tmpdest;
   char txident[80]; /*! \todo FIXME txident is replaced by rqnt_ident in endpoint.
         This should be obsoleted */
   char cxident[80];
   char callid[80];
   int cxmode;
   struct mgcp_request *cx_queue; /*!< pending CX commands */
   ast_mutex_t cx_queue_lock;     /*!< CX queue lock */
   int nat;
   int iseq;                      /*!< Not used? RTP? */
   int outgoing;
   int alreadygone;
   int sdpsent;
   struct cops_gate *gate;
   struct mgcp_subchannel *next;  /*!< for out circular linked list */
};

#define MGCP_ONHOOK  1
#define MGCP_OFFHOOK 2

#define TYPE_TRUNK 1
#define TYPE_LINE  2

struct mgcp_endpoint {
   ast_mutex_t lock;
   char name[80];
   struct mgcp_subchannel *sub;     /*!< Pointer to our current connection, channel and stuff */
   char accountcode[AST_MAX_ACCOUNT_CODE];
   char exten[AST_MAX_EXTENSION];      /*!< Extention where to start */
   char context[AST_MAX_EXTENSION];
   char language[MAX_LANGUAGE];
   char cid_num[AST_MAX_EXTENSION]; /*!< Caller*ID number */
   char cid_name[AST_MAX_EXTENSION];   /*!< Caller*ID name */
   char lastcallerid[AST_MAX_EXTENSION];  /*!< Last Caller*ID */
   char dtmf_buf[AST_MAX_EXTENSION];   /*!< place to collect digits be */
   char call_forward[AST_MAX_EXTENSION];  /*!< Last Caller*ID */
   char musicclass[MAX_MUSICCLASS];
   char curtone[80];       /*!< Current tone */
   char mailbox[AST_MAX_EXTENSION];
   char parkinglot[AST_MAX_CONTEXT];   /*!< Parkinglot */
   struct ast_event_sub *mwi_event_sub;
   ast_group_t callgroup;
   ast_group_t pickupgroup;
   int callwaiting;
   int hascallwaiting;
   int transfer;
   int threewaycalling;
   int singlepath;
   int cancallforward;
   int directmedia;
   int callreturn;
   int dnd; /* How does this affect callwait? Do we just deny a mgcp_request if we're dnd? */
   int hascallerid;
   int hidecallerid;
   int dtmfmode;
   int amaflags;
   int ncs;
   int pktcgatealloc;
   int hangupongateremove;
   int type;
   int slowsequence;       /*!< MS: Sequence the endpoint as a whole */
   int group;
   int iseq; /*!< Not used? */
   int lastout; /*!< tracking this on the subchannels.  Is it needed here? */
   int needdestroy; /*!< Not used? */
   struct ast_format_cap *cap;
   int nonCodecCapability;
   int onhooktime;
   int msgstate; /*!< voicemail message state */
   int immediate;
   int hookstate;
   int adsi;
   char rqnt_ident[80];             /*!< request identifier */
   struct mgcp_request *rqnt_queue; /*!< pending RQNT commands */
   ast_mutex_t rqnt_queue_lock;
   struct mgcp_request *cmd_queue;  /*!< pending commands other than RQNT */
   ast_mutex_t cmd_queue_lock;
   int delme;                       /*!< needed for reload */
   int needaudit;                   /*!< needed for reload */
   struct ast_dsp *dsp; /*!< XXX Should there be a dsp/subchannel? XXX */
   /* owner is tracked on the subchannels, and the *sub indicates whos in charge */
   /* struct ast_channel *owner; */
   /* struct ast_rtp *rtp; */
   /* struct sockaddr_in tmpdest; */
   /* message go the the endpoint and not the channel so they stay here */
   struct ast_variable *chanvars;      /*!< Variables to set for channel created by user */
   struct mgcp_endpoint *next;
   struct mgcp_gateway *parent;
};

static struct mgcp_gateway {
   /* A gateway containing one or more endpoints */
   char name[80];
   int isnamedottedip; /*!< is the name FQDN or dotted ip */
   struct sockaddr_in addr;
   struct sockaddr_in defaddr;
   struct in_addr ourip;
   int dynamic;
   int expire;    /*!< XXX Should we ever expire dynamic registrations? XXX */
   struct mgcp_endpoint *endpoints;
   struct ast_ha *ha;
/* obsolete
   time_t lastouttime;
   int lastout;
   int messagepending;
*/
/* Wildcard endpoint name */
   char wcardep[30];
   struct mgcp_message *msgs; /*!< gw msg queue */
   ast_mutex_t msgs_lock;     /*!< queue lock */
   int retransid;             /*!< retrans timer id */
   int delme;                 /*!< needed for reload */
   int realtime;
   struct mgcp_response *responses;
   struct mgcp_gateway *next;
} *gateways = NULL;

AST_MUTEX_DEFINE_STATIC(mgcp_reload_lock);
static int mgcp_reloading = 0;

/*! \brief gatelock: mutex for gateway/endpoint lists */
AST_MUTEX_DEFINE_STATIC(gatelock);

static int mgcpsock  = -1;

static struct sockaddr_in bindaddr;

static struct ast_frame  *mgcp_read(struct ast_channel *ast);
static int transmit_response(struct mgcp_subchannel *sub, char *msg, struct mgcp_request *req, char *msgrest);
static int transmit_notify_request(struct mgcp_subchannel *sub, char *tone);
static int transmit_modify_request(struct mgcp_subchannel *sub);
static int transmit_connect(struct mgcp_subchannel *sub);
static int transmit_notify_request_with_callerid(struct mgcp_subchannel *sub, char *tone, char *callernum, char *callername);
static int transmit_modify_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp_instance *rtp, const struct ast_format_cap *codecs);
static int transmit_connection_del(struct mgcp_subchannel *sub);
static int transmit_audit_endpoint(struct mgcp_endpoint *p);
static void start_rtp(struct mgcp_subchannel *sub);
static void handle_response(struct mgcp_endpoint *p, struct mgcp_subchannel *sub,
                            int result, unsigned int ident, struct mgcp_request *resp);
static void dump_cmd_queues(struct mgcp_endpoint *p, struct mgcp_subchannel *sub);
static char *mgcp_reload(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);
static int reload_config(int reload);

static struct ast_channel *mgcp_request(const char *type, struct ast_format_cap *cap, const struct ast_channel *requestor, const char *dest, int *cause);
static int mgcp_call(struct ast_channel *ast, const char *dest, int timeout);
static int mgcp_hangup(struct ast_channel *ast);
static int mgcp_answer(struct ast_channel *ast);
static struct ast_frame *mgcp_read(struct ast_channel *ast);
static int mgcp_write(struct ast_channel *ast, struct ast_frame *frame);
static int mgcp_indicate(struct ast_channel *ast, int ind, const void *data, size_t datalen);
static int mgcp_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);
static int mgcp_senddigit_begin(struct ast_channel *ast, char digit);
static int mgcp_senddigit_end(struct ast_channel *ast, char digit, unsigned int duration);
static int mgcp_devicestate(const char *data);
static void add_header_offhook(struct mgcp_subchannel *sub, struct mgcp_request *resp, char *tone);
static int transmit_connect_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp_instance *rtp);
static struct mgcp_gateway *build_gateway(char *cat, struct ast_variable *v);
static int mgcp_alloc_pktcgate(struct mgcp_subchannel *sub);
static int acf_channel_read(struct ast_channel *chan, const char *funcname, char *preparse, char *buf, size_t buflen);
static struct ast_variable *add_var(const char *buf, struct ast_variable *list);
static struct ast_variable *copy_vars(struct ast_variable *src);

static struct ast_channel_tech mgcp_tech = {
   .type = "MGCP",
   .description = tdesc,
   .properties = AST_CHAN_TP_WANTSJITTER | AST_CHAN_TP_CREATESJITTER,
   .requester = mgcp_request,
   .devicestate = mgcp_devicestate,
   .call = mgcp_call,
   .hangup = mgcp_hangup,
   .answer = mgcp_answer,
   .read = mgcp_read,
   .write = mgcp_write,
   .indicate = mgcp_indicate,
   .fixup = mgcp_fixup,
   .send_digit_begin = mgcp_senddigit_begin,
   .send_digit_end = mgcp_senddigit_end,
   .bridge = ast_rtp_instance_bridge,
   .func_channel_read = acf_channel_read,
};

static void mwi_event_cb(const struct ast_event *event, void *userdata)
{
   /* This module does not handle MWI in an event-based manner.  However, it
    * subscribes to MWI for each mailbox that is configured so that the core
    * knows that we care about it.  Then, chan_mgcp will get the MWI from the
    * event cache instead of checking the mailbox directly. */
}

static int has_voicemail(struct mgcp_endpoint *p)
{
   int new_msgs;
   struct ast_event *event;
   char *mbox, *cntx;

   cntx = mbox = ast_strdupa(p->mailbox);
   strsep(&cntx, "@");
   if (ast_strlen_zero(cntx))
      cntx = "default";

   event = ast_event_get_cached(AST_EVENT_MWI,
      AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mbox,
      AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, cntx,
      AST_EVENT_IE_END);

   if (event) {
      new_msgs = ast_event_get_ie_uint(event, AST_EVENT_IE_NEWMSGS);
      ast_event_destroy(event);
   } else
      new_msgs = ast_app_has_voicemail(p->mailbox, NULL);

   return new_msgs;
}

static int unalloc_sub(struct mgcp_subchannel *sub)
{
   struct mgcp_endpoint *p = sub->parent;
   if (p->sub == sub) {
      ast_log(LOG_WARNING, "Trying to unalloc the real channel %s@%s?!?\n", p->name, p->parent->name);
      return -1;
   }
   ast_debug(1, "Released sub %d of channel %s@%s\n", sub->id, p->name, p->parent->name);

   sub->owner = NULL;
   if (!ast_strlen_zero(sub->cxident)) {
      transmit_connection_del(sub);
   }
   sub->cxident[0] = '\0';
   sub->callid[0] = '\0';
   sub->cxmode = MGCP_CX_INACTIVE;
   sub->outgoing = 0;
   sub->alreadygone = 0;
   memset(&sub->tmpdest, 0, sizeof(sub->tmpdest));
   if (sub->rtp) {
      ast_rtp_instance_destroy(sub->rtp);
      sub->rtp = NULL;
   }
   dump_cmd_queues(NULL, sub);
   return 0;
}

/* modified for new transport mechanism */
static int __mgcp_xmit(struct mgcp_gateway *gw, char *data, int len)
{
   int res;
   if (gw->addr.sin_addr.s_addr)
      res=sendto(mgcpsock, data, len, 0, (struct sockaddr *)&gw->addr, sizeof(struct sockaddr_in));
   else
      res=sendto(mgcpsock, data, len, 0, (struct sockaddr *)&gw->defaddr, sizeof(struct sockaddr_in));
   if (res != len) {
      ast_log(LOG_WARNING, "mgcp_xmit returned %d: %s\n", res, strerror(errno));
   }
   return res;
}

static int resend_response(struct mgcp_subchannel *sub, struct mgcp_response *resp)
{
   struct mgcp_endpoint *p = sub->parent;
   int res;
   ast_debug(1, "Retransmitting:\n%s\n to %s:%d\n", resp->buf, ast_inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));
   res = __mgcp_xmit(p->parent, resp->buf, resp->len);
   if (res > 0)
      res = 0;
   return res;
}

static int send_response(struct mgcp_subchannel *sub, struct mgcp_request *req)
{
   struct mgcp_endpoint *p = sub->parent;
   int res;
   ast_debug(1, "Transmitting:\n%s\n to %s:%d\n", req->data, ast_inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));
   res = __mgcp_xmit(p->parent, req->data, req->len);
   if (res > 0)
      res = 0;
   return res;
}

/* modified for new transport framework */
static void dump_queue(struct mgcp_gateway *gw, struct mgcp_endpoint *p)
{
   struct mgcp_message *cur, *q = NULL, *w, *prev;

   ast_mutex_lock(&gw->msgs_lock);
   for (prev = NULL, cur = gw->msgs; cur; prev = cur, cur = cur->next) {
      if (!p || cur->owner_ep == p) {
         if (prev) {
            prev->next = cur->next;
         } else {
            gw->msgs = cur->next;
         }

         ast_log(LOG_NOTICE, "Removing message from %s transaction %u\n",
            gw->name, cur->seqno);

         w = cur;
         if (q) {
            w->next = q;
         } else {
            w->next = NULL;
         }
         q = w;
      }
   }
   ast_mutex_unlock(&gw->msgs_lock);

   while (q) {
      cur = q;
      q = q->next;
      ast_free(cur);
   }
}

static void mgcp_queue_frame(struct mgcp_subchannel *sub, struct ast_frame *f)
{
   for (;;) {
      if (sub->owner) {
         if (!ast_channel_trylock(sub->owner)) {
            ast_queue_frame(sub->owner, f);
            ast_channel_unlock(sub->owner);
            break;
         } else {
            DEADLOCK_AVOIDANCE(&sub->lock);
         }
      } else {
         break;
      }
   }
}

static void mgcp_queue_hangup(struct mgcp_subchannel *sub)
{
   for (;;) {
      if (sub->owner) {
         if (!ast_channel_trylock(sub->owner)) {
            ast_queue_hangup(sub->owner);
            ast_channel_unlock(sub->owner);
            break;
         } else {
            DEADLOCK_AVOIDANCE(&sub->lock);
         }
      } else {
         break;
      }
   }
}

static void mgcp_queue_control(struct mgcp_subchannel *sub, int control)
{
   struct ast_frame f = { AST_FRAME_CONTROL, { control } };
   return mgcp_queue_frame(sub, &f);
}

static int retrans_pkt(const void *data)
{
   struct mgcp_gateway *gw = (struct mgcp_gateway *)data;
   struct mgcp_message *cur, *exq = NULL, *w, *prev;
   int res = 0;

   /* find out expired msgs */
   ast_mutex_lock(&gw->msgs_lock);

   for (prev = NULL, cur = gw->msgs; cur; prev = cur, cur = cur->next) {
      if (cur->retrans < MAX_RETRANS) {
         cur->retrans++;
         ast_debug(1, "Retransmitting #%d transaction %u on [%s]\n",
            cur->retrans, cur->seqno, gw->name);
         __mgcp_xmit(gw, cur->buf, cur->len);
      } else {
         if (prev)
            prev->next = cur->next;
         else
            gw->msgs = cur->next;

         ast_log(LOG_WARNING, "Maximum retries exceeded for transaction %u on [%s]\n",
            cur->seqno, gw->name);

         w = cur;

         if (exq) {
            w->next = exq;
         } else {
            w->next = NULL;
         }
         exq = w;
      }
   }

   if (!gw->msgs) {
      gw->retransid = -1;
      res = 0;
   } else {
      res = 1;
   }
   ast_mutex_unlock(&gw->msgs_lock);

   while (exq) {
      cur = exq;
      /* time-out transaction */
      handle_response(cur->owner_ep, cur->owner_sub, 406, cur->seqno, NULL);
      exq = exq->next;
      ast_free(cur);
   }

   return res;
}

/* modified for the new transaction mechanism */
static int mgcp_postrequest(struct mgcp_endpoint *p, struct mgcp_subchannel *sub,
                            char *data, int len, unsigned int seqno)
{
   struct mgcp_message *msg;
   struct mgcp_message *cur;
   struct mgcp_gateway *gw;
   struct timeval now;

   if (!(msg = ast_malloc(sizeof(*msg) + len))) {
      return -1;
   }
   if (!(gw = ((p && p->parent) ? p->parent : NULL))) {
      ast_free(msg);
      return -1;
   }

   msg->owner_sub = sub;
   msg->owner_ep = p;
   msg->seqno = seqno;
   msg->next = NULL;
   msg->len = len;
   msg->retrans = 0;
   memcpy(msg->buf, data, msg->len);

   ast_mutex_lock(&gw->msgs_lock);
   for (cur = gw->msgs; cur && cur->next; cur = cur->next);
   if (cur) {
      cur->next = msg;
   } else {
      gw->msgs = msg;
   }

   now = ast_tvnow();
   msg->expire = now.tv_sec * 1000 + now.tv_usec / 1000 + DEFAULT_RETRANS;

   if (gw->retransid == -1)
      gw->retransid = ast_sched_add(sched, DEFAULT_RETRANS, retrans_pkt, (void *)gw);
   ast_mutex_unlock(&gw->msgs_lock);
   __mgcp_xmit(gw, msg->buf, msg->len);
   /* XXX Should schedule retransmission XXX */
   return 0;
}

/* modified for new transport */
static int send_request(struct mgcp_endpoint *p, struct mgcp_subchannel *sub,
                        struct mgcp_request *req, unsigned int seqno)
{
   int res = 0;
   struct mgcp_request **queue, *q, *r, *t;
   ast_mutex_t *l;

   ast_debug(1, "Slow sequence is %d\n", p->slowsequence);
   if (p->slowsequence) {
      queue = &p->cmd_queue;
      l = &p->cmd_queue_lock;
      ast_mutex_lock(l);
   } else {
      switch (req->cmd) {
      case MGCP_CMD_DLCX:
         queue = &sub->cx_queue;
         l = &sub->cx_queue_lock;
         ast_mutex_lock(l);
         q = sub->cx_queue;
         /* delete pending cx cmds */
         /* buggy sb5120 */
         if (!sub->parent->ncs) {
            while (q) {
               r = q->next;
               ast_free(q);
               q = r;
            }
            *queue = NULL;
         }
         break;

      case MGCP_CMD_CRCX:
      case MGCP_CMD_MDCX:
         queue = &sub->cx_queue;
         l = &sub->cx_queue_lock;
         ast_mutex_lock(l);
         break;

      case MGCP_CMD_RQNT:
         queue = &p->rqnt_queue;
         l = &p->rqnt_queue_lock;
         ast_mutex_lock(l);
         break;

      default:
         queue = &p->cmd_queue;
         l = &p->cmd_queue_lock;
         ast_mutex_lock(l);
         break;
      }
   }

   if (!(r = ast_malloc(sizeof(*r)))) {
      ast_log(LOG_WARNING, "Cannot post MGCP request: insufficient memory\n");
      ast_mutex_unlock(l);
      return -1;
   }
   memcpy(r, req, sizeof(*r));

   if (!(*queue)) {
      ast_debug(1, "Posting Request:\n%s to %s:%d\n", req->data,
         ast_inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));

      res = mgcp_postrequest(p, sub, req->data, req->len, seqno);
   } else {
      ast_debug(1, "Queueing Request:\n%s to %s:%d\n", req->data,
         ast_inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));
   }

   /* XXX find tail. We could also keep tail in the data struct for faster access */
   for (t = *queue; t && t->next; t = t->next);

   r->next = NULL;
   if (t)
      t->next = r;
   else
      *queue = r;

   ast_mutex_unlock(l);

   return res;
}

static int mgcp_call(struct ast_channel *ast, const char *dest, int timeout)
{
   int res;
   struct mgcp_endpoint *p;
   struct mgcp_subchannel *sub;
   char tone[50] = "";
   const char *distinctive_ring = NULL;
   struct varshead *headp;
   struct ast_var_t *current;

   ast_debug(3, "MGCP mgcp_call(%s)\n", ast_channel_name(ast));
   sub = ast_channel_tech_pvt(ast);
   p = sub->parent;
   headp = ast_channel_varshead(ast);
   AST_LIST_TRAVERSE(headp,current,entries) {
      /* Check whether there is an ALERT_INFO variable */
      if (strcasecmp(ast_var_name(current),"ALERT_INFO") == 0) {
         distinctive_ring = ast_var_value(current);
      }
   }

   ast_mutex_lock(&sub->lock);
   switch (p->hookstate) {
   case MGCP_OFFHOOK:
      if (!ast_strlen_zero(distinctive_ring)) {
         snprintf(tone, sizeof(tone), "L/wt%s", distinctive_ring);
         ast_debug(3, "MGCP distinctive callwait %s\n", tone);
      } else {
         ast_copy_string(tone, (p->ncs ? "L/wt1" : "L/wt"), sizeof(tone));
         ast_debug(3, "MGCP normal callwait %s\n", tone);
      }
      break;
   case MGCP_ONHOOK:
   default:
      if (!ast_strlen_zero(distinctive_ring)) {
         snprintf(tone, sizeof(tone), "L/r%s", distinctive_ring);
         ast_debug(3, "MGCP distinctive ring %s\n", tone);
      } else {
         ast_copy_string(tone, "L/rg", sizeof(tone));
         ast_debug(3, "MGCP default ring\n");
      }
      break;
   }

   if ((ast_channel_state(ast) != AST_STATE_DOWN) && (ast_channel_state(ast) != AST_STATE_RESERVED)) {
      ast_log(LOG_WARNING, "mgcp_call called on %s, neither down nor reserved\n", ast_channel_name(ast));
      ast_mutex_unlock(&sub->lock);
      return -1;
   }

   res = 0;
   sub->outgoing = 1;
   sub->cxmode = MGCP_CX_RECVONLY;
   ast_setstate(ast, AST_STATE_RINGING);
   if (p->type == TYPE_LINE) {
      if (!sub->rtp) {
         start_rtp(sub);
      } else {
         transmit_modify_request(sub);
      }

      if (sub->next->owner && !ast_strlen_zero(sub->next->cxident) && !ast_strlen_zero(sub->next->callid)) {
         /* try to prevent a callwait from disturbing the other connection */
         sub->next->cxmode = MGCP_CX_RECVONLY;
         transmit_modify_request(sub->next);
      }

      transmit_notify_request_with_callerid(sub, tone,
         S_COR(ast_channel_connected(ast)->id.number.valid, ast_channel_connected(ast)->id.number.str, ""),
         S_COR(ast_channel_connected(ast)->id.name.valid, ast_channel_connected(ast)->id.name.str, ""));
      ast_setstate(ast, AST_STATE_RINGING);

      if (sub->next->owner && !ast_strlen_zero(sub->next->cxident) && !ast_strlen_zero(sub->next->callid)) {
         /* Put the connection back in sendrecv */
         sub->next->cxmode = MGCP_CX_SENDRECV;
         transmit_modify_request(sub->next);
      }
   } else {
      ast_log(LOG_NOTICE, "Don't know how to dial on trunks yet\n");
      res = -1;
   }
   ast_mutex_unlock(&sub->lock);
   return res;
}

static int mgcp_hangup(struct ast_channel *ast)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   struct mgcp_endpoint *p = sub->parent;
   struct ast_channel *bridged;

   ast_debug(1, "mgcp_hangup(%s)\n", ast_channel_name(ast));
   if (!ast_channel_tech_pvt(ast)) {
      ast_debug(1, "Asked to hangup channel not connected\n");
      return 0;
   }
   if (strcmp(sub->magic, MGCP_SUBCHANNEL_MAGIC)) {
      ast_debug(1, "Invalid magic. MGCP subchannel freed up already.\n");
      return 0;
   }
   ast_mutex_lock(&sub->lock);
   ast_debug(3, "MGCP mgcp_hangup(%s) on %s@%s\n", ast_channel_name(ast), p->name, p->parent->name);

   if ((p->dtmfmode & MGCP_DTMF_INBAND) && p->dsp) {
      /* check whether other channel is active. */
      if (!sub->next->owner) {
         if (p->dtmfmode & MGCP_DTMF_HYBRID) {
            p->dtmfmode &= ~MGCP_DTMF_INBAND;
         }
         ast_debug(2, "MGCP free dsp on %s@%s\n", p->name, p->parent->name);
         ast_dsp_free(p->dsp);
         p->dsp = NULL;
      }
   }

   sub->owner = NULL;

   /* for deleting gate */
   if (p->pktcgatealloc && sub->gate) {
      sub->gate->gate_open = NULL;
      sub->gate->gate_remove = NULL;
      sub->gate->got_dq_gi = NULL;
      sub->gate->tech_pvt = NULL;
      if (sub->gate->state == GATE_ALLOC_PROGRESS || sub->gate->state == GATE_ALLOCATED) {
         ast_pktccops_gate_alloc(GATE_DEL, sub->gate, 0, 0, 0, 0, 0, 0, NULL, NULL);
      } else {
         sub->gate->deltimer = time(NULL) + 5;
      }
      sub->gate = NULL;
   }

   if (!ast_strlen_zero(sub->cxident)) {
      transmit_connection_del(sub);
   }
   sub->cxident[0] = '\0';
   if ((sub == p->sub) && sub->next->owner) {
      if (p->hookstate == MGCP_OFFHOOK) {
         if (sub->next->owner && ast_bridged_channel(sub->next->owner)) {
            /* ncs fix! */
            bridged = ast_bridged_channel(sub->next->owner);
            transmit_notify_request_with_callerid(p->sub, (p->ncs ? "L/wt1" : "L/wt"),
               S_COR(ast_channel_caller(bridged)->id.number.valid, ast_channel_caller(bridged)->id.number.str, ""),
               S_COR(ast_channel_caller(bridged)->id.name.valid, ast_channel_caller(bridged)->id.name.str, ""));
         }
      } else {
         /* set our other connection as the primary and swith over to it */
         p->sub = sub->next;
         p->sub->cxmode = MGCP_CX_RECVONLY;
         transmit_modify_request(p->sub);
         if (sub->next->owner && ast_bridged_channel(sub->next->owner)) {
            bridged = ast_bridged_channel(sub->next->owner);
            transmit_notify_request_with_callerid(p->sub, "L/rg",
               S_COR(ast_channel_caller(bridged)->id.number.valid, ast_channel_caller(bridged)->id.number.str, ""),
               S_COR(ast_channel_caller(bridged)->id.name.valid, ast_channel_caller(bridged)->id.name.str, ""));
         }
      }

   } else if ((sub == p->sub->next) && p->hookstate == MGCP_OFFHOOK) {
      transmit_notify_request(sub, p->ncs ? "" : "L/v");
   } else if (p->hookstate == MGCP_OFFHOOK) {
      transmit_notify_request(sub, "L/ro");
   } else {
      transmit_notify_request(sub, "");
   }

   ast_channel_tech_pvt_set(ast, NULL);
   sub->alreadygone = 0;
   sub->outgoing = 0;
   sub->cxmode = MGCP_CX_INACTIVE;
   sub->callid[0] = '\0';
   if (p) {
      memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
   }
   /* Reset temporary destination */
   memset(&sub->tmpdest, 0, sizeof(sub->tmpdest));
   if (sub->rtp) {
      ast_rtp_instance_destroy(sub->rtp);
      sub->rtp = NULL;
   }

   ast_module_unref(ast_module_info->self);

   if ((p->hookstate == MGCP_ONHOOK) && (!sub->next->rtp)) {
      p->hidecallerid = 0;
      if (p->hascallwaiting && !p->callwaiting) {
         ast_verb(3, "Enabling call waiting on %s\n", ast_channel_name(ast));
         p->callwaiting = -1;
      }
      if (has_voicemail(p)) {
         ast_debug(3, "MGCP mgcp_hangup(%s) on %s@%s set vmwi(+)\n",
            ast_channel_name(ast), p->name, p->parent->name);
         transmit_notify_request(sub, "L/vmwi(+)");
      } else {
         ast_debug(3, "MGCP mgcp_hangup(%s) on %s@%s set vmwi(-)\n",
            ast_channel_name(ast), p->name, p->parent->name);
         transmit_notify_request(sub, "L/vmwi(-)");
      }
   }
   ast_mutex_unlock(&sub->lock);
   return 0;
}

static char *handle_mgcp_show_endpoints(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct mgcp_gateway  *mg;
   struct mgcp_endpoint *me;
   int hasendpoints = 0;
   struct ast_variable * v = NULL;

   switch (cmd) {
   case CLI_INIT:
      e->command = "mgcp show endpoints";
      e->usage =
         "Usage: mgcp show endpoints\n"
         "       Lists all endpoints known to the MGCP (Media Gateway Control Protocol) subsystem.\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 3) {
      return CLI_SHOWUSAGE;
   }
   ast_mutex_lock(&gatelock);
   for (mg = gateways; mg; mg = mg->next) {
      ast_cli(a->fd, "Gateway '%s' at %s (%s%s)\n", mg->name, mg->addr.sin_addr.s_addr ? ast_inet_ntoa(mg->addr.sin_addr) : ast_inet_ntoa(mg->defaddr.sin_addr), mg->realtime ? "Realtime, " : "", mg->dynamic ? "Dynamic" : "Static");
      for (me = mg->endpoints; me; me = me->next) {
         ast_cli(a->fd, "   -- '%s@%s in '%s' is %s\n", me->name, mg->name, me->context, me->sub->owner ? "active" : "idle");
         if (me->chanvars) {
            ast_cli(a->fd, "  Variables:\n");
            for (v = me->chanvars ; v ; v = v->next) {
               ast_cli(a->fd, "    %s = '%s'\n", v->name, v->value);
            }
         }
         hasendpoints = 1;
      }
      if (!hasendpoints) {
         ast_cli(a->fd, "   << No Endpoints Defined >>     ");
      }
   }
   ast_mutex_unlock(&gatelock);
   return CLI_SUCCESS;
}

static char *handle_mgcp_audit_endpoint(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct mgcp_gateway  *mg;
   struct mgcp_endpoint *me;
   int found = 0;
   char *ename,*gname, *c;

   switch (cmd) {
   case CLI_INIT:
      e->command = "mgcp audit endpoint";
      e->usage =
         "Usage: mgcp audit endpoint <endpointid>\n"
         "       Lists the capabilities of an endpoint in the MGCP (Media Gateway Control Protocol) subsystem.\n"
         "       mgcp debug MUST be on to see the results of this command.\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (!mgcpdebug) {
      return CLI_SHOWUSAGE;
   }
   if (a->argc != 4)
      return CLI_SHOWUSAGE;
   /* split the name into parts by null */
   ename = ast_strdupa(a->argv[3]);
   for (gname = ename; *gname; gname++) {
      if (*gname == '@') {
         *gname = 0;
         gname++;
         break;
      }
   }
   if (gname[0] == '[') {
      gname++;
   }
   if ((c = strrchr(gname, ']'))) {
      *c = '\0';
   }
   ast_mutex_lock(&gatelock);
   for (mg = gateways; mg; mg = mg->next) {
      if (!strcasecmp(mg->name, gname)) {
         for (me = mg->endpoints; me; me = me->next) {
            if (!strcasecmp(me->name, ename)) {
               found = 1;
               transmit_audit_endpoint(me);
               break;
            }
         }
         if (found) {
            break;
         }
      }
   }
   if (!found) {
      ast_cli(a->fd, "   << Could not find endpoint >>     ");
   }
   ast_mutex_unlock(&gatelock);
   return CLI_SUCCESS;
}

static char *handle_mgcp_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   switch (cmd) {
   case CLI_INIT:
      e->command = "mgcp set debug {on|off}";
      e->usage =
         "Usage: mgcp set debug {on|off}\n"
         "       Enables/Disables dumping of MGCP packets for debugging purposes\n";   
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != e->args)
      return CLI_SHOWUSAGE;

   if (!strncasecmp(a->argv[e->args - 1], "on", 2)) {
      mgcpdebug = 1;
      ast_cli(a->fd, "MGCP Debugging Enabled\n");
   } else if (!strncasecmp(a->argv[3], "off", 3)) {
      mgcpdebug = 0;
      ast_cli(a->fd, "MGCP Debugging Disabled\n");
   } else {
      return CLI_SHOWUSAGE;
   }
   return CLI_SUCCESS;
}

static struct ast_cli_entry cli_mgcp[] = {
   AST_CLI_DEFINE(handle_mgcp_audit_endpoint, "Audit specified MGCP endpoint"),
   AST_CLI_DEFINE(handle_mgcp_show_endpoints, "List defined MGCP endpoints"),
   AST_CLI_DEFINE(handle_mgcp_set_debug, "Enable/Disable MGCP debugging"),
   AST_CLI_DEFINE(mgcp_reload, "Reload MGCP configuration"),
};

static int mgcp_answer(struct ast_channel *ast)
{
   int res = 0;
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   struct mgcp_endpoint *p = sub->parent;

   ast_mutex_lock(&sub->lock);
   sub->cxmode = MGCP_CX_SENDRECV;
   if (!sub->rtp) {
      start_rtp(sub);
   } else {
      transmit_modify_request(sub);
   }
   ast_verb(3, "MGCP mgcp_answer(%s) on %s@%s-%d\n",
         ast_channel_name(ast), p->name, p->parent->name, sub->id);
   if (ast_channel_state(ast) != AST_STATE_UP) {
      ast_setstate(ast, AST_STATE_UP);
      ast_debug(1, "mgcp_answer(%s)\n", ast_channel_name(ast));
      transmit_notify_request(sub, "");
      transmit_modify_request(sub);
   }
   ast_mutex_unlock(&sub->lock);
   return res;
}

static struct ast_frame *mgcp_rtp_read(struct mgcp_subchannel *sub)
{
   /* Retrieve audio/etc from channel.  Assumes sub->lock is already held. */
   struct ast_frame *f;

   f = ast_rtp_instance_read(sub->rtp, 0);
   /* Don't send RFC2833 if we're not supposed to */
   if (f && (f->frametype == AST_FRAME_DTMF) && !(sub->parent->dtmfmode & MGCP_DTMF_RFC2833))
      return &ast_null_frame;
   if (sub->owner) {
      /* We already hold the channel lock */
      if (f->frametype == AST_FRAME_VOICE) {
         if (!ast_format_cap_iscompatible(ast_channel_nativeformats(sub->owner), &f->subclass.format)) {
            ast_debug(1, "Oooh, format changed to %s\n", ast_getformatname(&f->subclass.format));
            ast_format_cap_set(ast_channel_nativeformats(sub->owner), &f->subclass.format);
            ast_set_read_format(sub->owner, ast_channel_readformat(sub->owner));
            ast_set_write_format(sub->owner, ast_channel_writeformat(sub->owner));
         }
         /* Courtesy fearnor aka alex@pilosoft.com */
         if ((sub->parent->dtmfmode & MGCP_DTMF_INBAND) && (sub->parent->dsp)) {
#if 0
            ast_log(LOG_NOTICE, "MGCP ast_dsp_process\n");
#endif
            f = ast_dsp_process(sub->owner, sub->parent->dsp, f);
         }
      }
   }
   return f;
}


static struct ast_frame *mgcp_read(struct ast_channel *ast)
{
   struct ast_frame *f;
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   ast_mutex_lock(&sub->lock);
   f = mgcp_rtp_read(sub);
   ast_mutex_unlock(&sub->lock);
   return f;
}

static int mgcp_write(struct ast_channel *ast, struct ast_frame *frame)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   int res = 0;
   char buf[256];

   if (frame->frametype != AST_FRAME_VOICE) {
      if (frame->frametype == AST_FRAME_IMAGE)
         return 0;
      else {
         ast_log(LOG_WARNING, "Can't send %d type frames with MGCP write\n", frame->frametype);
         return 0;
      }
   } else {
      if (!(ast_format_cap_iscompatible(ast_channel_nativeformats(ast), &frame->subclass.format))) {
         ast_log(LOG_WARNING, "Asked to transmit frame type %s, while native formats is %s (read/write = %s/%s)\n",
            ast_getformatname(&frame->subclass.format),
            ast_getformatname_multiple(buf, sizeof(buf), ast_channel_nativeformats(ast)),
            ast_getformatname(ast_channel_readformat(ast)),
            ast_getformatname(ast_channel_writeformat(ast)));
         /* return -1; */
      }
   }
   if (sub) {
      ast_mutex_lock(&sub->lock);
      if (!sub->sdpsent && sub->gate) {
         if (sub->gate->state == GATE_ALLOCATED) {
            ast_debug(1, "GATE ALLOCATED, sending sdp\n");
            transmit_modify_with_sdp(sub, NULL, 0);
         }
      }
      if ((sub->parent->sub == sub) || !sub->parent->singlepath) {
         if (sub->rtp) {
            res =  ast_rtp_instance_write(sub->rtp, frame);
         }
      }
      ast_mutex_unlock(&sub->lock);
   }
   return res;
}

static int mgcp_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(newchan);

   ast_mutex_lock(&sub->lock);
   ast_log(LOG_NOTICE, "mgcp_fixup(%s, %s)\n", ast_channel_name(oldchan), ast_channel_name(newchan));
   if (sub->owner != oldchan) {
      ast_mutex_unlock(&sub->lock);
      ast_log(LOG_WARNING, "old channel wasn't %p but was %p\n", oldchan, sub->owner);
      return -1;
   }
   sub->owner = newchan;
   ast_mutex_unlock(&sub->lock);
   return 0;
}

static int mgcp_senddigit_begin(struct ast_channel *ast, char digit)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   struct mgcp_endpoint *p = sub->parent;
   int res = 0;

   ast_mutex_lock(&sub->lock);
   if (p->dtmfmode & MGCP_DTMF_INBAND || p->dtmfmode & MGCP_DTMF_HYBRID) {
      ast_debug(1, "Sending DTMF using inband/hybrid\n");
      res = -1; /* Let asterisk play inband indications */
   } else if (p->dtmfmode & MGCP_DTMF_RFC2833) {
      ast_debug(1, "Sending DTMF using RFC2833\n");
      ast_rtp_instance_dtmf_begin(sub->rtp, digit);
   } else {
      ast_log(LOG_ERROR, "Don't know about DTMF_MODE %d\n", p->dtmfmode);
   }
   ast_mutex_unlock(&sub->lock);

   return res;
}

static int mgcp_senddigit_end(struct ast_channel *ast, char digit, unsigned int duration)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   struct mgcp_endpoint *p = sub->parent;
   int res = 0;
   char tmp[4];

   ast_mutex_lock(&sub->lock);
   if (p->dtmfmode & MGCP_DTMF_INBAND || p->dtmfmode & MGCP_DTMF_HYBRID) {
      ast_debug(1, "Stopping DTMF using inband/hybrid\n");
      res = -1; /* Tell Asterisk to stop inband indications */
   } else if (p->dtmfmode & MGCP_DTMF_RFC2833) {
      ast_debug(1, "Stopping DTMF using RFC2833\n");
      if (sub->parent->ncs) {
         tmp[0] = digit;
         tmp[1] = '\0';
      } else {
         tmp[0] = 'D';
         tmp[1] = '/';
         tmp[2] = digit;
         tmp[3] = '\0';
      }
      transmit_notify_request(sub, tmp);
      ast_rtp_instance_dtmf_end(sub->rtp, digit);
   } else {
      ast_log(LOG_ERROR, "Don't know about DTMF_MODE %d\n", p->dtmfmode);
   }
   ast_mutex_unlock(&sub->lock);

   return res;
}

/*!
 *  \brief  mgcp_devicestate: channel callback for device status monitoring
 *  \param  data tech/resource name of MGCP device to query
 *
 * Callback for device state management in channel subsystem
 * to obtain device status (up/down) of a specific MGCP endpoint
 *
 *  \return device status result (from devicestate.h) AST_DEVICE_INVALID (not available) or AST_DEVICE_UNKNOWN (available but unknown state)
 */
static int mgcp_devicestate(const char *data)
{
   struct mgcp_gateway  *g;
   struct mgcp_endpoint *e = NULL;
   char *tmp, *endpt, *gw;
   int ret = AST_DEVICE_INVALID;

   endpt = ast_strdupa(data);
   if ((tmp = strchr(endpt, '@'))) {
      *tmp++ = '\0';
      gw = tmp;
   } else
      goto error;

   ast_mutex_lock(&gatelock);
   for (g = gateways; g; g = g->next) {
      if (strcasecmp(g->name, gw) == 0) {
         e = g->endpoints;
         break;
      }
   }

   if (!e)
      goto error;

   for (; e; e = e->next) {
      if (strcasecmp(e->name, endpt) == 0) {
         break;
      }
   }

   if (!e)
      goto error;

   /*
    * As long as the gateway/endpoint is valid, we'll
    * assume that the device is available and its state
    * can be tracked.
    */
   ret = AST_DEVICE_UNKNOWN;

error:
   ast_mutex_unlock(&gatelock);
   return ret;
}

static char *control2str(int ind) {
   switch (ind) {
   case AST_CONTROL_HANGUP:
      return "Other end has hungup";
   case AST_CONTROL_RING:
      return "Local ring";
   case AST_CONTROL_RINGING:
      return "Remote end is ringing";
   case AST_CONTROL_ANSWER:
      return "Remote end has answered";
   case AST_CONTROL_BUSY:
      return "Remote end is busy";
   case AST_CONTROL_TAKEOFFHOOK:
      return "Make it go off hook";
   case AST_CONTROL_OFFHOOK:
      return "Line is off hook";
   case AST_CONTROL_CONGESTION:
      return "Congestion (circuits busy)";
   case AST_CONTROL_FLASH:
      return "Flash hook";
   case AST_CONTROL_WINK:
      return "Wink";
   case AST_CONTROL_OPTION:
      return "Set a low-level option";
   case AST_CONTROL_RADIO_KEY:
      return "Key Radio";
   case AST_CONTROL_RADIO_UNKEY:
      return "Un-Key Radio";
   }
   return "UNKNOWN";
}

static int mgcp_indicate(struct ast_channel *ast, int ind, const void *data, size_t datalen)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(ast);
   int res = 0;

   ast_debug(3, "MGCP asked to indicate %d '%s' condition on channel %s\n",
      ind, control2str(ind), ast_channel_name(ast));
   ast_mutex_lock(&sub->lock);
   switch(ind) {
   case AST_CONTROL_RINGING:
#ifdef DLINK_BUGGY_FIRMWARE   
      transmit_notify_request(sub, "rt");
#else
      if (!sub->sdpsent) { /* will hide the inband progress!!! */
         transmit_notify_request(sub, sub->parent->ncs ? "L/rt" : "G/rt");
      }
#endif
      break;
   case AST_CONTROL_BUSY:
      transmit_notify_request(sub, "L/bz");
      break;
   case AST_CONTROL_INCOMPLETE:
      /* We do not currently support resetting of the Interdigit Timer, so treat
       * Incomplete control frames as a congestion response
       */
   case AST_CONTROL_CONGESTION:
      transmit_notify_request(sub, sub->parent->ncs ? "L/cg" : "G/cg");
      break;
   case AST_CONTROL_HOLD:
      ast_moh_start(ast, data, NULL);
      break;
   case AST_CONTROL_UNHOLD:
      ast_moh_stop(ast);
      break;
   case AST_CONTROL_SRCUPDATE:
      ast_rtp_instance_update_source(sub->rtp);
      break;
   case AST_CONTROL_SRCCHANGE:
      ast_rtp_instance_change_source(sub->rtp);
      break;
   case AST_CONTROL_PROGRESS:
   case AST_CONTROL_PROCEEDING:
      transmit_modify_request(sub);
   case -1:
      transmit_notify_request(sub, "");
      break;
   default:
      ast_log(LOG_WARNING, "Don't know how to indicate condition %d\n", ind);
      /* fallthrough */
   case AST_CONTROL_PVT_CAUSE_CODE:
      res = -1;
   }
   ast_mutex_unlock(&sub->lock);
   return res;
}

static struct ast_channel *mgcp_new(struct mgcp_subchannel *sub, int state, const char *linkedid)
{
   struct ast_channel *tmp;
   struct ast_variable *v = NULL;
   struct mgcp_endpoint *i = sub->parent;
   struct ast_format tmpfmt;

   tmp = ast_channel_alloc(1, state, i->cid_num, i->cid_name, linkedid, i->accountcode, i->exten, i->context, i->amaflags, "MGCP/%s@%s-%d", i->name, i->parent->name, sub->id);
   if (tmp) {
      ast_channel_tech_set(tmp, &mgcp_tech);
      ast_format_cap_copy(ast_channel_nativeformats(tmp), i->cap);
      if (ast_format_cap_is_empty(ast_channel_nativeformats(tmp))) {
         ast_format_cap_copy(ast_channel_nativeformats(tmp), global_capability);
      }
      if (sub->rtp) {
         ast_channel_set_fd(tmp, 0, ast_rtp_instance_fd(sub->rtp, 0));
      }
      if (i->dtmfmode & (MGCP_DTMF_INBAND | MGCP_DTMF_HYBRID)) {
         i->dsp = ast_dsp_new();
         ast_dsp_set_features(i->dsp, DSP_FEATURE_DIGIT_DETECT);
         /* this is to prevent clipping of dtmf tones during dsp processing */
         ast_dsp_set_digitmode(i->dsp, DSP_DIGITMODE_NOQUELCH);
      } else {
         i->dsp = NULL;
      }
      if (state == AST_STATE_RING)
         ast_channel_rings_set(tmp, 1);

      ast_best_codec(ast_channel_nativeformats(tmp), &tmpfmt);
      ast_format_copy(ast_channel_writeformat(tmp), &tmpfmt);
      ast_format_copy(ast_channel_rawwriteformat(tmp), &tmpfmt);
      ast_format_copy(ast_channel_readformat(tmp), &tmpfmt);
      ast_format_copy(ast_channel_rawreadformat(tmp), &tmpfmt);
      ast_channel_tech_pvt_set(tmp, sub);
      if (!ast_strlen_zero(i->language))
         ast_channel_language_set(tmp, i->language);
      if (!ast_strlen_zero(i->accountcode))
         ast_channel_accountcode_set(tmp, i->accountcode);
      if (i->amaflags)
         ast_channel_amaflags_set(tmp, i->amaflags);
      sub->owner = tmp;
      ast_module_ref(ast_module_info->self);
      ast_channel_callgroup_set(tmp, i->callgroup);
      ast_channel_pickupgroup_set(tmp, i->pickupgroup);
      ast_channel_call_forward_set(tmp, i->call_forward);
      ast_channel_context_set(tmp, i->context);
      ast_channel_exten_set(tmp, i->exten);

      /* Don't use ast_set_callerid() here because it will
       * generate a needless NewCallerID event */
      if (!ast_strlen_zero(i->cid_num)) {
         ast_channel_caller(tmp)->ani.number.valid = 1;
         ast_channel_caller(tmp)->ani.number.str = ast_strdup(i->cid_num);
      }

      if (!i->adsi) {
         ast_channel_adsicpe_set(tmp, AST_ADSI_UNAVAILABLE);
      }
      ast_channel_priority_set(tmp, 1);

      /* Set channel variables for this call from configuration */
      for (v = i->chanvars ; v ; v = v->next) {
         char valuebuf[1024];
         pbx_builtin_setvar_helper(tmp, v->name, ast_get_encoded_str(v->value, valuebuf, sizeof(valuebuf)));
      }

      if (sub->rtp) {
         ast_jb_configure(tmp, &global_jbconf);
      }
      if (state != AST_STATE_DOWN) {
         if (ast_pbx_start(tmp)) {
            ast_log(LOG_WARNING, "Unable to start PBX on %s\n", ast_channel_name(tmp));
            ast_hangup(tmp);
            tmp = NULL;
         }
      }
      ast_verb(3, "MGCP mgcp_new(%s) created in state: %s\n",
            ast_channel_name(tmp), ast_state2str(state));
   } else {
      ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
   }
   return tmp;
}

static char *get_sdp_by_line(char* line, char *name, int nameLen)
{
   if (strncasecmp(line, name, nameLen) == 0 && line[nameLen] == '=') {
      char *r = line + nameLen + 1;
      while (*r && (*r < 33)) ++r;
      return r;
   }
   return "";
}

static char *get_sdp(struct mgcp_request *req, char *name)
{
   int x;
   int len = strlen(name);
   char *r;

   for (x = 0; x < req->lines; x++) {
      r = get_sdp_by_line(req->line[x], name, len);
      if (r[0] != '\0') return r;
   }
   return "";
}

static void sdpLineNum_iterator_init(int *iterator)
{
   *iterator = 0;
}

static char *get_sdp_iterate(int* iterator, struct mgcp_request *req, char *name)
{
   int len = strlen(name);
   char *r;
   while (*iterator < req->lines) {
      r = get_sdp_by_line(req->line[(*iterator)++], name, len);
      if (r[0] != '\0') return r;
   }
   return "";
}

static char *__get_header(struct mgcp_request *req, char *name, int *start, char *def)
{
   int x;
   int len = strlen(name);
   char *r;
   for (x = *start; x < req->headers; x++) {
      if (!strncasecmp(req->header[x], name, len) &&
          (req->header[x][len] == ':')) {
         r = req->header[x] + len + 1;
         while (*r && (*r < 33)) {
            r++;
         }
         *start = x + 1;
         return r;
      }
   }
   /* Don't return NULL, so get_header is always a valid pointer */
   return def;
}

static char *get_header(struct mgcp_request *req, char *name)
{
   int start = 0;
   return __get_header(req, name, &start, "");
}

/*! \brief get_csv: (SC:) get comma separated value */
static char *get_csv(char *c, int *len, char **next)
{
   char *s;

   *next = NULL, *len = 0;
   if (!c) return NULL;

   while (*c && (*c < 33 || *c == ',')) {
      c++;
   }

   s = c;
   while (*c && (*c >= 33 && *c != ',')) {
      c++, (*len)++;
   }
   *next = c;

   if (*len == 0) {
      s = NULL, *next = NULL;
   }

   return s;
}

static struct mgcp_gateway *find_realtime_gw(char *name, char *at, struct sockaddr_in *sin)
{
   struct mgcp_gateway *g = NULL;
   struct ast_variable *mgcpgwconfig = NULL;
   struct ast_variable *gwv, *epname = NULL;
   struct mgcp_endpoint *e;
   char lines[256];
   int i, j;

   ast_debug(1, "*** find Realtime MGCPGW\n");

   if (!(i = ast_check_realtime("mgcpgw")) || !(j = ast_check_realtime("mgcpep"))) {
      return NULL;
   }

   if (ast_strlen_zero(at)) {
      ast_debug(1, "null gw name\n");
      return NULL;
   }

   if (!(mgcpgwconfig = ast_load_realtime("mgcpgw", "name", at, NULL))) {
      return NULL;
   }

   /*!
    * \note This is a fairly odd way of instantiating lines.  Instead of each
    * line created by virtue of being in the database (and loaded via
    * ast_load_realtime_multientry), this code forces a specific order with a
    * "lines" entry in the "mgcpgw" record.  This has benefits, because as with
    * chan_dahdi, values are inherited across definitions.  The downside is
    * that it's not as clear what the values will be simply by looking at a
    * single row in the database, and it's probable that the sanest configuration
    * should have the first column in the "mgcpep" table be "clearvars", with a
    * static value of "all", if any variables are set at all.  It may be worth
    * making this assumption explicit in the code in the future, and then just
    * using ast_load_realtime_multientry for the "mgcpep" records.
    */
   lines[0] = '\0';
   for (gwv = mgcpgwconfig; gwv; gwv = gwv->next) {
      if (!strcasecmp(gwv->name, "lines")) {
         ast_copy_string(lines, gwv->value, sizeof(lines));
         break;
      }
   }
   /* Position gwv at the end of the list */
   for (gwv = gwv && gwv->next ? gwv : mgcpgwconfig; gwv->next; gwv = gwv->next);

   if (!ast_strlen_zero(lines)) {
      AST_DECLARE_APP_ARGS(args,
         AST_APP_ARG(line)[100];
      );
      AST_STANDARD_APP_ARGS(args, lines);
      for (i = 0; i < args.argc; i++) {
         gwv->next = ast_load_realtime("mgcpep", "name", at, "line", args.line[i], NULL);

         /* Remove "line" AND position gwv at the end of the list. */
         for (epname = NULL; gwv->next; gwv = gwv->next) {
            if (!strcasecmp(gwv->next->name, "line")) {
               /* Remove it from the list */
               epname = gwv->next;
               gwv->next = gwv->next->next;
            }
         }
         /* Since "line" instantiates the configuration, we have to move it to the end. */
         if (epname) {
            gwv->next = epname;
            epname->next = NULL;
            gwv = gwv->next;
         }
      }
   }
   for (gwv = mgcpgwconfig; gwv; gwv = gwv->next) {
      ast_debug(1, "MGCP Realtime var: %s => %s\n", gwv->name, gwv->value);
   }

   if (mgcpgwconfig) {
      g = build_gateway(at, mgcpgwconfig);
      ast_variables_destroy(mgcpgwconfig);
   }
   if (g) {
      g->next = gateways;
      g->realtime = 1;
      gateways = g;
      for (e = g->endpoints; e; e = e->next) {
         transmit_audit_endpoint(e);
         e->needaudit = 0;
      }
   }
   return g;
}

static struct mgcp_subchannel *find_subchannel_and_lock(char *name, int msgid, struct sockaddr_in *sin)
{
   struct mgcp_endpoint *p = NULL;
   struct mgcp_subchannel *sub = NULL;
   struct mgcp_gateway *g;
   char tmp[256] = "";
   char *at = NULL, *c;
   int found = 0;
   if (name) {
      ast_copy_string(tmp, name, sizeof(tmp));
      at = strchr(tmp, '@');
      if (!at) {
         ast_log(LOG_NOTICE, "Endpoint '%s' has no at sign!\n", name);
         return NULL;
      }
      *at++ = '\0';
   }
   ast_mutex_lock(&gatelock);
   if (at && (at[0] == '[')) {
      at++;
      c = strrchr(at, ']');
      if (c) {
         *c = '\0';
      }
   }
   for (g = gateways ? gateways : find_realtime_gw(name, at, sin); g; g = g->next ? g->next : find_realtime_gw(name, at, sin)) {
      if ((!name || !strcasecmp(g->name, at)) &&
          (sin || g->addr.sin_addr.s_addr || g->defaddr.sin_addr.s_addr)) {
         /* Found the gateway.  If it's dynamic, save it's address -- now for the endpoint */
         if (sin && g->dynamic && name) {
            if ((g->addr.sin_addr.s_addr != sin->sin_addr.s_addr) ||
               (g->addr.sin_port != sin->sin_port)) {
               memcpy(&g->addr, sin, sizeof(g->addr));
               {
                  struct ast_sockaddr tmp1, tmp2;
                  struct sockaddr_in tmp3 = {0,};

                  tmp3.sin_addr = g->ourip;
                  ast_sockaddr_from_sin(&tmp1, &g->addr);
                  ast_sockaddr_from_sin(&tmp2, &tmp3);
                  if (ast_ouraddrfor(&tmp1, &tmp2)) {
                     memcpy(&g->ourip, &__ourip, sizeof(g->ourip));
                  }
                  ast_sockaddr_to_sin(&tmp2, &tmp3);
                  g->ourip = tmp3.sin_addr;
               }
               ast_verb(3, "Registered MGCP gateway '%s' at %s port %d\n", g->name, ast_inet_ntoa(g->addr.sin_addr), ntohs(g->addr.sin_port));
            }
         /* not dynamic, check if the name matches */
         } else if (name) {
            if (strcasecmp(g->name, at)) {
               g = g->next;
               continue;
            }
         /* not dynamic, no name, check if the addr matches */
         } else if (!name && sin) {
            if ((g->addr.sin_addr.s_addr != sin->sin_addr.s_addr) ||
                (g->addr.sin_port != sin->sin_port)) {
               if(!g->next)
                  g = find_realtime_gw(name, at, sin);
               else
                  g = g->next;
               continue;
            }
         } else {
            continue;
         }
         for (p = g->endpoints; p; p = p->next) {
            ast_debug(1, "Searching on %s@%s for subchannel\n", p->name, g->name);
            if (msgid) {
               sub = p->sub;
               found = 1;
               break;
            } else if (name && !strcasecmp(p->name, tmp)) {
               ast_debug(1, "Coundn't determine subchannel, assuming current master %s@%s-%d\n",
                  p->name, g->name, p->sub->id);
               sub = p->sub;
               found = 1;
               break;
            }
         }
         if (sub && found) {
            ast_mutex_lock(&sub->lock);
            break;
         }
      }
   }
   ast_mutex_unlock(&gatelock);
   if (!sub) {
      if (name) {
         if (g) {
            ast_log(LOG_NOTICE, "Endpoint '%s' not found on gateway '%s'\n", tmp, at);
         } else {
            ast_log(LOG_NOTICE, "Gateway '%s' (and thus its endpoint '%s') does not exist\n", at, tmp);
         }
      }
   }
   return sub;
}

static void parse(struct mgcp_request *req)
{
   /* Divide fields by NULL's */
   char *c;
   int f = 0;
   c = req->data;

   /* First header starts immediately */
   req->header[f] = c;
   for (; *c; c++) {
      if (*c == '\n') {
         /* We've got a new header */
         *c = 0;
         ast_debug(3, "Header: %s (%d)\n", req->header[f], (int) strlen(req->header[f]));
         if (ast_strlen_zero(req->header[f])) {
            /* Line by itself means we're now in content */
            c++;
            break;
         }
         if (f >= MGCP_MAX_HEADERS - 1) {
            ast_log(LOG_WARNING, "Too many MGCP headers...\n");
         } else {
            f++;
         }
         req->header[f] = c + 1;
      } else if (*c == '\r') {
         /* Ignore but eliminate \r's */
         *c = 0;
      }
   }
   /* Check for last header */
   if (!ast_strlen_zero(req->header[f])) {
      f++;
   }
   req->headers = f;
   /* Now we process any mime content */
   f = 0;
   req->line[f] = c;
   for (; *c; c++) {
      if (*c == '\n') {
         /* We've got a new line */
         *c = 0;
         ast_debug(3, "Line: %s (%d)\n", req->line[f], (int) strlen(req->line[f]));
         if (f >= MGCP_MAX_LINES - 1) {
            ast_log(LOG_WARNING, "Too many SDP lines...\n");
         } else {
            f++;
         }
         req->line[f] = c + 1;
      } else if (*c == '\r') {
         /* Ignore and eliminate \r's */
         *c = 0;
      }
   }
   /* Check for last line */
   if (!ast_strlen_zero(req->line[f])) {
      f++;
   }
   req->lines = f;
   /* Parse up the initial header */
   c = req->header[0];
   while (*c && *c < 33) c++;
   /* First the verb */
   req->verb = c;
   while (*c && (*c > 32)) c++;
   if (*c) {
      *c = '\0';
      c++;
      while (*c && (*c < 33)) c++;
      req->identifier = c;
      while (*c && (*c > 32)) c++;
      if (*c) {
         *c = '\0';
         c++;
         while (*c && (*c < 33)) c++;
         req->endpoint = c;
         while (*c && (*c > 32)) c++;
         if (*c) {
            *c = '\0';
            c++;
            while (*c && (*c < 33)) c++;
            req->version = c;
            while (*c && (*c > 32)) c++;
            while (*c && (*c < 33)) c++;
            while (*c && (*c > 32)) c++;
            *c = '\0';
         }
      }
   }

   ast_debug(1, "Verb: '%s', Identifier: '%s', Endpoint: '%s', Version: '%s'\n",
         req->verb, req->identifier, req->endpoint, req->version);
   ast_debug(1, "%d headers, %d lines\n", req->headers, req->lines);
   if (*c) {
      ast_log(LOG_WARNING, "Odd content, extra stuff left over ('%s')\n", c);
   }
}

static int process_sdp(struct mgcp_subchannel *sub, struct mgcp_request *req)
{
   char *m;
   char *c;
   char *a;
   char host[258];
   int len = 0;
   int portno;
   struct ast_format_cap *peercap;
   int peerNonCodecCapability;
   struct sockaddr_in sin;
   struct ast_sockaddr sin_tmp;
   char *codecs;
   struct ast_hostent ahp; struct hostent *hp;
   int codec, codec_count=0;
   int iterator;
   struct mgcp_endpoint *p = sub->parent;
   char tmp1[256], tmp2[256], tmp3[256];

   /* Get codec and RTP info from SDP */
   m = get_sdp(req, "m");
   c = get_sdp(req, "c");
   if (ast_strlen_zero(m) || ast_strlen_zero(c)) {
      ast_log(LOG_WARNING, "Insufficient information for SDP (m = '%s', c = '%s')\n", m, c);
      return -1;
   }
   if (sscanf(c, "IN IP4 %256s", host) != 1) {
      ast_log(LOG_WARNING, "Invalid host in c= line, '%s'\n", c);
      return -1;
   }
   /* XXX This could block for a long time, and block the main thread! XXX */
   hp = ast_gethostbyname(host, &ahp);
   if (!hp) {
      ast_log(LOG_WARNING, "Unable to lookup host in c= line, '%s'\n", c);
      return -1;
   }
   if (sscanf(m, "audio %30d RTP/AVP %n", &portno, &len) != 1 || !len) {
      ast_log(LOG_WARNING, "Malformed media stream descriptor: %s\n", m);
      return -1;
   }
   sin.sin_family = AF_INET;
   memcpy(&sin.sin_addr, hp->h_addr, sizeof(sin.sin_addr));
   sin.sin_port = htons(portno);
   ast_sockaddr_from_sin(&sin_tmp, &sin);
   ast_rtp_instance_set_remote_address(sub->rtp, &sin_tmp);
   ast_debug(3, "Peer RTP is at port %s:%d\n", ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
   /* Scan through the RTP payload types specified in a "m=" line: */
   ast_rtp_codecs_payloads_clear(ast_rtp_instance_get_codecs(sub->rtp), sub->rtp);
   codecs = ast_strdupa(m + len);
   while (!ast_strlen_zero(codecs)) {
      if (sscanf(codecs, "%30d%n", &codec, &len) != 1) {
         if (codec_count) {
            break;
         }
         ast_log(LOG_WARNING, "Error in codec string '%s' at '%s'\n", m, codecs);
         return -1;
      }
      ast_rtp_codecs_payloads_set_m_type(ast_rtp_instance_get_codecs(sub->rtp), sub->rtp, codec);
      codec_count++;
      codecs += len;
   }

   /* Next, scan through each "a=rtpmap:" line, noting each */
   /* specified RTP payload type (with corresponding MIME subtype): */
   sdpLineNum_iterator_init(&iterator);
   while ((a = get_sdp_iterate(&iterator, req, "a"))[0] != '\0') {
      char* mimeSubtype = ast_strdupa(a); /* ensures we have enough space */
      if (sscanf(a, "rtpmap: %30u %127[^/]/", &codec, mimeSubtype) != 2)
         continue;
      /* Note: should really look at the 'freq' and '#chans' params too */
      ast_rtp_codecs_payloads_set_rtpmap_type(ast_rtp_instance_get_codecs(sub->rtp), sub->rtp, codec, "audio", mimeSubtype, 0);
   }

   /* Now gather all of the codecs that were asked for: */
   if (!(peercap = ast_format_cap_alloc_nolock())) {
      return -1;
   }
   ast_rtp_codecs_payload_formats(ast_rtp_instance_get_codecs(sub->rtp), peercap, &peerNonCodecCapability);
   ast_format_cap_joint_copy(global_capability, peercap, p->cap);
   ast_debug(1, "Capabilities: us - %s, them - %s, combined - %s\n",
      ast_getformatname_multiple(tmp1, sizeof(tmp1), global_capability),
      ast_getformatname_multiple(tmp2, sizeof(tmp2), peercap),
      ast_getformatname_multiple(tmp3, sizeof(tmp3), p->cap));
   peercap = ast_format_cap_destroy(peercap);

   ast_debug(1, "Non-codec capabilities: us - %d, them - %d, combined - %d\n",
      nonCodecCapability, peerNonCodecCapability, p->nonCodecCapability);
   if (ast_format_cap_is_empty(p->cap)) {
      ast_log(LOG_WARNING, "No compatible codecs!\n");
      return -1;
   }
   return 0;
}

static int add_header(struct mgcp_request *req, const char *var, const char *value)
{
   if (req->len >= sizeof(req->data) - 4) {
      ast_log(LOG_WARNING, "Out of space, can't add anymore\n");
      return -1;
   }
   if (req->lines) {
      ast_log(LOG_WARNING, "Can't add more headers when lines have been added\n");
      return -1;
   }
   req->header[req->headers] = req->data + req->len;
   snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s: %s\r\n", var, value);
   req->len += strlen(req->header[req->headers]);
   if (req->headers < MGCP_MAX_HEADERS) {
      req->headers++;
   } else {
      ast_log(LOG_WARNING, "Out of header space\n");
      return -1;
   }
   return 0;
}

static int add_line(struct mgcp_request *req, char *line)
{
   if (req->len >= sizeof(req->data) - 4) {
      ast_log(LOG_WARNING, "Out of space, can't add anymore\n");
      return -1;
   }
   if (!req->lines) {
      /* Add extra empty return */
      ast_copy_string(req->data + req->len, "\r\n", sizeof(req->data) - req->len);
      req->len += strlen(req->data + req->len);
   }
   req->line[req->lines] = req->data + req->len;
   snprintf(req->line[req->lines], sizeof(req->data) - req->len, "%s", line);
   req->len += strlen(req->line[req->lines]);
   if (req->lines < MGCP_MAX_LINES) {
      req->lines++;
   } else {
      ast_log(LOG_WARNING, "Out of line space\n");
      return -1;
   }
   return 0;
}

static int init_resp(struct mgcp_request *req, char *resp, struct mgcp_request *orig, char *resprest)
{
   /* Initialize a response */
   if (req->headers || req->len) {
      ast_log(LOG_WARNING, "Request already initialized?!?\n");
      return -1;
   }
   req->header[req->headers] = req->data + req->len;
   snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %s %s\r\n", resp, orig->identifier, resprest);
   req->len += strlen(req->header[req->headers]);
   if (req->headers < MGCP_MAX_HEADERS) {
      req->headers++;
   } else {
      ast_log(LOG_WARNING, "Out of header space\n");
   }
   return 0;
}

static int init_req(struct mgcp_endpoint *p, struct mgcp_request *req, char *verb, unsigned int oseq)
{
   /* Initialize a response */
   if (req->headers || req->len) {
      ast_log(LOG_WARNING, "Request already initialized?!?\n");
      return -1;
   }
   req->header[req->headers] = req->data + req->len;
   /* check if we need brackets around the gw name */
   if (p->parent->isnamedottedip) {
      snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %d %s@[%s] MGCP 1.0%s\r\n", verb, oseq, p->name, p->parent->name, p->ncs ? " NCS 1.0" : "");
   } else {
+     snprintf(req->header[req->headers], sizeof(req->data) - req->len, "%s %d %s@%s MGCP 1.0%s\r\n", verb, oseq, p->name, p->parent->name, p->ncs ? " NCS 1.0" : "");
   }
   req->len += strlen(req->header[req->headers]);
   if (req->headers < MGCP_MAX_HEADERS) {
      req->headers++;
   } else {
      ast_log(LOG_WARNING, "Out of header space\n");
   }
   return 0;
}


static int respprep(struct mgcp_request *resp, struct mgcp_endpoint *p, char *msg, struct mgcp_request *req, char *msgrest)
{
   memset(resp, 0, sizeof(*resp));
   init_resp(resp, msg, req, msgrest);
   return 0;
}

static int reqprep(struct mgcp_request *req, struct mgcp_endpoint *p, char *verb)
{
   unsigned int oseq;
   memset(req, 0, sizeof(struct mgcp_request));
   ast_mutex_lock(&oseq_lock);
   oseq_global++;
   if (oseq_global > 999999999) {
      oseq_global = 1;
   }
   oseq = oseq_global;
   ast_mutex_unlock(&oseq_lock);
   init_req(p, req, verb, oseq);
   return oseq;
}

static int transmit_response(struct mgcp_subchannel *sub, char *msg, struct mgcp_request *req, char *msgrest)
{
   struct mgcp_request resp;
   struct mgcp_endpoint *p = sub->parent;
   struct mgcp_response *mgr;

   if (!sub) {
      return -1;
   }

   respprep(&resp, p, msg, req, msgrest);
   if (!(mgr = ast_calloc(1, sizeof(*mgr) + resp.len + 1))) {
      return send_response(sub, &resp);
   }
   /* Store MGCP response in case we have to retransmit */
   sscanf(req->identifier, "%30d", &mgr->seqno);
   time(&mgr->whensent);
   mgr->len = resp.len;
   memcpy(mgr->buf, resp.data, resp.len);
   mgr->buf[resp.len] = '\0';
   mgr->next = p->parent->responses;
   p->parent->responses = mgr;

   return send_response(sub, &resp);
}


static int add_sdp(struct mgcp_request *resp, struct mgcp_subchannel *sub, struct ast_rtp_instance *rtp)
{
   int len;
   int codec;
   char costr[80];
   struct sockaddr_in sin;
   struct ast_sockaddr sin_tmp;
   char v[256];
   char s[256];
   char o[256];
   char c[256];
   char t[256];
   char m[256] = "";
   char a[1024] = "";
   int x;
   struct ast_format tmpfmt;
   struct sockaddr_in dest = { 0, };
   struct ast_sockaddr dest_tmp;
   struct mgcp_endpoint *p = sub->parent;
   /* XXX We break with the "recommendation" and send our IP, in order that our
          peer doesn't have to ast_gethostbyname() us XXX */
   len = 0;
   if (!sub->rtp) {
      ast_log(LOG_WARNING, "No way to add SDP without an RTP structure\n");
      return -1;
   }
   ast_rtp_instance_get_local_address(sub->rtp, &sin_tmp);
   ast_sockaddr_to_sin(&sin_tmp, &sin);
   if (rtp) {
      ast_rtp_instance_get_remote_address(sub->rtp, &dest_tmp);
      ast_sockaddr_to_sin(&dest_tmp, &dest);
   } else {
      if (sub->tmpdest.sin_addr.s_addr) {
         dest.sin_addr = sub->tmpdest.sin_addr;
         dest.sin_port = sub->tmpdest.sin_port;
         /* Reset temporary destination */
         memset(&sub->tmpdest, 0, sizeof(sub->tmpdest));
      } else {
         dest.sin_addr = p->parent->ourip;
         dest.sin_port = sin.sin_port;
      }
   }
   ast_debug(1, "We're at %s port %d\n", ast_inet_ntoa(p->parent->ourip), ntohs(sin.sin_port));
   ast_copy_string(v, "v=0\r\n", sizeof(v));
   snprintf(o, sizeof(o), "o=root %d %d IN IP4 %s\r\n", (int)getpid(), (int)getpid(), ast_inet_ntoa(dest.sin_addr));
   ast_copy_string(s, "s=session\r\n", sizeof(s));
   snprintf(c, sizeof(c), "c=IN IP4 %s\r\n", ast_inet_ntoa(dest.sin_addr));
   ast_copy_string(t, "t=0 0\r\n", sizeof(t));
   snprintf(m, sizeof(m), "m=audio %d RTP/AVP", ntohs(dest.sin_port));

   ast_format_cap_iter_start(p->cap);
   while (!(ast_format_cap_iter_next(p->cap, &tmpfmt))) {
      if (AST_FORMAT_GET_TYPE(tmpfmt.id) != AST_FORMAT_TYPE_AUDIO) {
         /* Audio is now discontiguous */
         continue;
      }
      if (ast_format_cap_iscompatible(p->cap, &tmpfmt)) {
         ast_debug(1, "Answering with capability %s\n", ast_getformatname(&tmpfmt));
         codec = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(sub->rtp), 1, &tmpfmt, 0);
         if (codec > -1) {
            snprintf(costr, sizeof(costr), " %d", codec);
            strncat(m, costr, sizeof(m) - strlen(m) - 1);
            snprintf(costr, sizeof(costr), "a=rtpmap:%d %s/8000\r\n", codec, ast_rtp_lookup_mime_subtype2(1, &tmpfmt, 0, 0));
            strncat(a, costr, sizeof(a) - strlen(a) - 1);
         }
      }
   }
   ast_format_cap_iter_end(p->cap);

   for (x = 1LL; x <= AST_RTP_MAX; x <<= 1) {
      if (p->nonCodecCapability & x) {
         ast_debug(1, "Answering with non-codec capability %d\n", (int) x);
         codec = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(sub->rtp), 0, NULL, x);
         if (codec > -1) {
            snprintf(costr, sizeof(costr), " %d", codec);
            strncat(m, costr, sizeof(m) - strlen(m) - 1);
            snprintf(costr, sizeof(costr), "a=rtpmap:%d %s/8000\r\n", codec, ast_rtp_lookup_mime_subtype2(0, NULL, x, 0));
            strncat(a, costr, sizeof(a) - strlen(a) - 1);
            if (x == AST_RTP_DTMF) {
               /* Indicate we support DTMF...  Not sure about 16,
                  but MSN supports it so dang it, we will too... */
               snprintf(costr, sizeof costr, "a=fmtp:%d 0-16\r\n", codec);
               strncat(a, costr, sizeof(a) - strlen(a) - 1);
            }
         }
      }
   }
   strncat(m, "\r\n", sizeof(m) - strlen(m) - 1);
   len = strlen(v) + strlen(s) + strlen(o) + strlen(c) + strlen(t) + strlen(m) + strlen(a);
   snprintf(costr, sizeof(costr), "%d", len);
   add_line(resp, v);
   add_line(resp, o);
   add_line(resp, s);
   add_line(resp, c);
   add_line(resp, t);
   add_line(resp, m);
   add_line(resp, a);
   return 0;
}

static int transmit_modify_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp_instance *rtp, const struct ast_format_cap *codecs)
{
   struct mgcp_request resp;
   char local[256];
   char tmp[80];
   struct mgcp_endpoint *p = sub->parent;
   struct ast_format tmpfmt;
   struct ast_sockaddr sub_tmpdest_tmp;
   unsigned int oseq;

   if (ast_strlen_zero(sub->cxident) && rtp) {
      /* We don't have a CXident yet, store the destination and
         wait a bit */
      ast_rtp_instance_get_remote_address(rtp, &sub_tmpdest_tmp);
      ast_sockaddr_to_sin(&sub_tmpdest_tmp, &sub->tmpdest);
      return 0;
   }
   ast_copy_string(local, "e:on, s:off, p:20", sizeof(local));
   ast_format_cap_iter_start(p->cap);
   while (!(ast_format_cap_iter_next(p->cap, &tmpfmt))) {
      if (AST_FORMAT_GET_TYPE(tmpfmt.id) != AST_FORMAT_TYPE_AUDIO) {
         /* Audio is now discontiguous */
         continue;
      }
      if (ast_format_cap_iscompatible(p->cap, &tmpfmt)) {
         snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype2(1, &tmpfmt, 0, 0));
         strncat(local, tmp, sizeof(local) - strlen(local) - 1);
      }
   }
   ast_format_cap_iter_end(p->cap);

   if (sub->gate) {
      if (sub->gate->state == GATE_ALLOCATED || sub->gate->state == GATE_OPEN) {
         snprintf(tmp, sizeof(tmp), ", dq-gi:%x", sub->gate->gateid);
         strncat(local, tmp, sizeof(local) - strlen(local) - 1);
         sub->sdpsent = 1;
      } else {
         /* oops wait */
         ast_debug(1, "Waiting for opened gate...\n");
         sub->sdpsent = 0;
         return 0;
      }
   }


   oseq = reqprep(&resp, p, "MDCX");
   add_header(&resp, "C", sub->callid);
   add_header(&resp, "L", local);
   add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
   /* X header should not be sent. kept for compatibility */
   add_header(&resp, "X", sub->txident);
   add_header(&resp, "I", sub->cxident);
   /*add_header(&resp, "S", "");*/
   add_sdp(&resp, sub, rtp);
   /* fill in new fields */
   resp.cmd = MGCP_CMD_MDCX;
   resp.trid = oseq;
   return send_request(p, sub, &resp, oseq);
}

static int transmit_connect_with_sdp(struct mgcp_subchannel *sub, struct ast_rtp_instance *rtp)
{
   struct mgcp_request resp;
   char local[256];
   char tmp[80];
   struct ast_format tmpfmt;
   struct mgcp_endpoint *p = sub->parent;
   unsigned int oseq;

   ast_debug(3, "Creating connection for %s@%s-%d in cxmode: %s callid: %s\n",
       p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);

   ast_copy_string(local, "e:on, s:off, p:20", sizeof(local));

   ast_format_cap_iter_start(p->cap);
   while (!(ast_format_cap_iter_next(p->cap, &tmpfmt))) {
      if (AST_FORMAT_GET_TYPE(tmpfmt.id) != AST_FORMAT_TYPE_AUDIO) {
         /* Audio is now discontiguous */
         continue;
      }
      if (ast_format_cap_iscompatible(p->cap, &tmpfmt)) {
         snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype2(1, &tmpfmt, 0, 0));
         strncat(local, tmp, sizeof(local) - strlen(local) - 1);
      }
   }
   ast_format_cap_iter_end(p->cap);

   if (sub->gate) {
      if(sub->gate->state == GATE_ALLOCATED) {
         snprintf(tmp, sizeof(tmp), ", dq-gi:%x", sub->gate->gateid);
         strncat(local, tmp, sizeof(local) - strlen(local) - 1);
      }
   }
   sub->sdpsent = 1;
   oseq = reqprep(&resp, p, "CRCX");
   add_header(&resp, "C", sub->callid);
   add_header(&resp, "L", local);
   add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
   /* X header should not be sent. kept for compatibility */
   add_header(&resp, "X", sub->txident);
   /*add_header(&resp, "S", "");*/
   add_sdp(&resp, sub, rtp);
   /* fill in new fields */
   resp.cmd = MGCP_CMD_CRCX;
   resp.trid = oseq;
   return send_request(p, sub, &resp, oseq);
}

static int mgcp_pktcgate_remove(struct cops_gate *gate)
{
   struct mgcp_subchannel *sub = gate->tech_pvt;

   if (!sub) {
      return 1;
   }

   ast_mutex_lock(&sub->lock);
   ast_debug(1, "Pktc: gate 0x%x deleted\n", gate->gateid);
   if (sub->gate->state != GATE_CLOSED && sub->parent->hangupongateremove) {
      sub->gate = NULL;
      if (sub->owner) {
         ast_softhangup(sub->owner, AST_CAUSE_REQUESTED_CHAN_UNAVAIL);
         ast_channel_unlock(sub->owner);
      }
   } else {
      sub->gate = NULL;
   }
   ast_mutex_unlock(&sub->lock);
   return 1;
}

static int mgcp_pktcgate_open(struct cops_gate *gate)
{
   struct mgcp_subchannel *sub = gate->tech_pvt;
   if (!sub) {
      return 1;
   }
   ast_mutex_lock(&sub->lock);
   ast_debug(1, "Pktc: gate 0x%x open\n", gate->gateid);
   if (!sub->sdpsent) transmit_modify_with_sdp(sub, NULL, 0);
   ast_mutex_unlock(&sub->lock);
   return 1;
}

static int mgcp_alloc_pktcgate(struct mgcp_subchannel *sub)
{
   struct mgcp_endpoint *p = sub->parent;
   sub->gate = ast_pktccops_gate_alloc(GATE_SET, NULL, ntohl(p->parent->addr.sin_addr.s_addr),
               8, 128000, 232, 0, 0, NULL, &mgcp_pktcgate_remove);

   if (!sub->gate) {
      return 0;
   }
   sub->gate->tech_pvt = sub;
   sub->gate->gate_open = &mgcp_pktcgate_open;
   return 1;
}

static int transmit_connect(struct mgcp_subchannel *sub)
{
   struct mgcp_request resp;
   char local[256];
   char tmp[80];
   struct ast_format tmpfmt;
   struct mgcp_endpoint *p = sub->parent;
   unsigned int oseq;

   ast_copy_string(local, "p:20, s:off, e:on", sizeof(local));

   ast_format_cap_iter_start(p->cap);
   while (!(ast_format_cap_iter_next(p->cap, &tmpfmt))) {
      if (ast_format_cap_iscompatible(p->cap, &tmpfmt)) {
         snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype2(1, &tmpfmt, 0, 0));
         strncat(local, tmp, sizeof(local) - strlen(local) - 1);
      }
   }
   ast_format_cap_iter_end(p->cap);

   ast_debug(3, "Creating connection for %s@%s-%d in cxmode: %s callid: %s\n",
          p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);
   sub->sdpsent = 0;
   oseq = reqprep(&resp, p, "CRCX");
   add_header(&resp, "C", sub->callid);
   add_header(&resp, "L", local);
   add_header(&resp, "M", "inactive");
   /* X header should not be sent. kept for compatibility */
   add_header(&resp, "X", sub->txident);
   /*add_header(&resp, "S", "");*/
   /* fill in new fields */
   resp.cmd = MGCP_CMD_CRCX;
   resp.trid = oseq;
   return send_request(p, sub, &resp, oseq);
}

static int transmit_notify_request(struct mgcp_subchannel *sub, char *tone)
{
   struct mgcp_request resp;
   struct mgcp_endpoint *p = sub->parent;
   unsigned int oseq;

   ast_debug(3, "MGCP Asked to indicate tone: %s on  %s@%s-%d in cxmode: %s\n",
      tone, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode]);
   ast_copy_string(p->curtone, tone, sizeof(p->curtone));
   oseq = reqprep(&resp, p, "RQNT");
   add_header(&resp, "X", p->rqnt_ident);
   switch (p->hookstate) {
   case MGCP_ONHOOK:
      add_header(&resp, "R", "L/hd(N)");
      break;
   case MGCP_OFFHOOK:
      add_header_offhook(sub, &resp, tone);
      break;
   }
   if (!ast_strlen_zero(tone)) {
      add_header(&resp, "S", tone);
   }
   /* fill in new fields */
   resp.cmd = MGCP_CMD_RQNT;
   resp.trid = oseq;
   return send_request(p, NULL, &resp, oseq);
}

static int transmit_notify_request_with_callerid(struct mgcp_subchannel *sub, char *tone, char *callernum, char *callername)
{
   struct mgcp_request resp;
   char tone2[256];
   char *l, *n;
   struct timeval t = ast_tvnow();
   struct ast_tm tm;
   struct mgcp_endpoint *p = sub->parent;
   unsigned int oseq;

   ast_localtime(&t, &tm, NULL);
   n = callername;
   l = callernum;
   if (!n)
      n = "";
   if (!l)
      l = "";

   /* Keep track of last callerid for blacklist and callreturn */
   ast_copy_string(p->lastcallerid, l, sizeof(p->lastcallerid));

   snprintf(tone2, sizeof(tone2), "%s,L/ci(%02d/%02d/%02d/%02d,%s,%s)", tone,
      tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, l, n);
   ast_copy_string(p->curtone, tone, sizeof(p->curtone));
   oseq = reqprep(&resp, p, "RQNT");
   add_header(&resp, "X", p->rqnt_ident);
   switch (p->hookstate) {
   case MGCP_ONHOOK:
      add_header(&resp, "R", "L/hd(N)");
      break;
   case MGCP_OFFHOOK:
      add_header_offhook(sub, &resp, tone);
      break;
   }
   if (!ast_strlen_zero(tone2)) {
      add_header(&resp, "S", tone2);
   }
   ast_debug(3, "MGCP Asked to indicate tone: %s on  %s@%s-%d in cxmode: %s\n",
      tone2, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode]);
   /* fill in new fields */
   resp.cmd = MGCP_CMD_RQNT;
   resp.trid = oseq;
   return send_request(p, NULL, &resp, oseq);
}

static int transmit_modify_request(struct mgcp_subchannel *sub)
{
   struct mgcp_request resp;
   struct mgcp_endpoint *p = sub->parent;
   struct ast_format tmpfmt;
   int fc = 1;
   char local[256];
   char tmp[80];
   unsigned int oseq;

   if (ast_strlen_zero(sub->cxident)) {
      /* We don't have a CXident yet, store the destination and
         wait a bit */
      return 0;
   }
   ast_debug(3, "Modified %s@%s-%d with new mode: %s on callid: %s\n",
      p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);

   ast_copy_string(local, "", sizeof(local));
   ast_format_cap_iter_start(p->cap);
   while (!(ast_format_cap_iter_next(p->cap, &tmpfmt))) {
      if (p->ncs && !fc) {
         ast_format_cap_set(p->cap, &tmpfmt); /* sb5120e bug */
         break;
      } else {
         fc = 0;
         snprintf(tmp, sizeof(tmp), ", a:%s", ast_rtp_lookup_mime_subtype2(1, &tmpfmt, 0, 0));
      }
      strncat(local, tmp, sizeof(local) - strlen(local) - 1);
   }
   ast_format_cap_iter_end(p->cap);

   if (!sub->sdpsent) {
      if (sub->gate) {
         if (sub->gate->state == GATE_ALLOCATED || sub->gate->state == GATE_OPEN) {
            snprintf(tmp, sizeof(tmp), ", dq-gi:%x", sub->gate->gateid);
            strncat(local, tmp, sizeof(local) - strlen(local) - 1);
         } else {
               /* we still don't have gateid wait */
            return 0;
         }
      }
   }

   oseq = reqprep(&resp, p, "MDCX");
   add_header(&resp, "C", sub->callid);
   if (!sub->sdpsent) {
      add_header(&resp, "L", local);
   }
   add_header(&resp, "M", mgcp_cxmodes[sub->cxmode]);
   /* X header should not be sent. kept for compatibility */
   add_header(&resp, "X", sub->txident);
   add_header(&resp, "I", sub->cxident);
   switch (sub->parent->hookstate) {
   case MGCP_ONHOOK:
      add_header(&resp, "R", "L/hd(N)");
      break;
   case MGCP_OFFHOOK:
      add_header_offhook(sub, &resp, "");
      break;
   }
   if (!sub->sdpsent) {
      add_sdp(&resp, sub, NULL);
      sub->sdpsent = 1;
   }
   /* fill in new fields */
   resp.cmd = MGCP_CMD_MDCX;
   resp.trid = oseq;
   return send_request(p, sub, &resp, oseq);
}


static void add_header_offhook(struct mgcp_subchannel *sub, struct mgcp_request *resp, char *tone)
{
   struct mgcp_endpoint *p = sub->parent;
   char tone_indicate_end = 0;

   /* We also should check the tone to indicate, because it have no sense
      to request notify D/[0-9#*] (dtmf keys) if we are sending congestion
      tone for example G/cg */
   if (p && (!strcasecmp(tone, (p->ncs ? "L/ro" : "G/cg")))) {
      tone_indicate_end = 1;
   }

   if (p && p->sub && p->sub->owner &&
         ast_channel_state(p->sub->owner) >= AST_STATE_RINGING &&
         (p->dtmfmode & (MGCP_DTMF_INBAND | MGCP_DTMF_HYBRID))) {
       add_header(resp, "R", "L/hu(N),L/hf(N)");

   } else if (!tone_indicate_end){
       add_header(resp, "R", (p->ncs ? "L/hu(N),L/hf(N),L/[0-9#*](N)" : "L/hu(N),L/hf(N),D/[0-9#*](N)"));
   } else {
      ast_debug(1, "We don't want more digits if we will end the call\n");
      add_header(resp, "R", "L/hu(N),L/hf(N)");
   }
}




static int transmit_audit_endpoint(struct mgcp_endpoint *p)
{
   struct mgcp_request resp;
   unsigned int oseq;
   oseq = reqprep(&resp, p, "AUEP");
   /* removed unknown param VS */
   /*add_header(&resp, "F", "A,R,D,S,X,N,I,T,O,ES,E,MD,M");*/
   add_header(&resp, "F", "A");
   /* fill in new fields */
   resp.cmd = MGCP_CMD_AUEP;
   resp.trid = oseq;
   return send_request(p, NULL, &resp, oseq);
}

static int transmit_connection_del(struct mgcp_subchannel *sub)
{
   struct mgcp_endpoint *p = sub->parent;
   struct mgcp_request resp;
   unsigned int oseq;

   ast_debug(3, "Delete connection %s %s@%s-%d with new mode: %s on callid: %s\n",
      sub->cxident, p->name, p->parent->name, sub->id, mgcp_cxmodes[sub->cxmode], sub->callid);
   oseq = reqprep(&resp, p, "DLCX");
   /* check if call id is avail */
   if (sub->callid[0])
      add_header(&resp, "C", sub->callid);
   /* X header should not be sent. kept for compatibility */
   add_header(&resp, "X", sub->txident);
   /* check if cxident is avail */
   if (sub->cxident[0])
      add_header(&resp, "I", sub->cxident);
   /* fill in new fields */
   resp.cmd = MGCP_CMD_DLCX;
   resp.trid = oseq;
   return send_request(p, sub, &resp, oseq);
}

static int transmit_connection_del_w_params(struct mgcp_endpoint *p, char *callid, char *cxident)
{
   struct mgcp_request resp;
   unsigned int oseq;

   ast_debug(3, "Delete connection %s %s@%s on callid: %s\n",
      cxident ? cxident : "", p->name, p->parent->name, callid ? callid : "");
   oseq = reqprep(&resp, p, "DLCX");
   /* check if call id is avail */
   if (callid && *callid)
      add_header(&resp, "C", callid);
   /* check if cxident is avail */
   if (cxident && *cxident)
      add_header(&resp, "I", cxident);
   /* fill in new fields */
   resp.cmd = MGCP_CMD_DLCX;
   resp.trid = oseq;
   return send_request(p, p->sub, &resp, oseq);
}

/*! \brief  dump_cmd_queues: (SC:) cleanup pending commands */
static void dump_cmd_queues(struct mgcp_endpoint *p, struct mgcp_subchannel *sub)
{
   struct mgcp_request *t, *q;

   if (p) {
      ast_mutex_lock(&p->rqnt_queue_lock);
      for (q = p->rqnt_queue; q; t = q->next, ast_free(q), q=t);
      p->rqnt_queue = NULL;
      ast_mutex_unlock(&p->rqnt_queue_lock);

      ast_mutex_lock(&p->cmd_queue_lock);
      for (q = p->cmd_queue; q; t = q->next, ast_free(q), q=t);
      p->cmd_queue = NULL;
      ast_mutex_unlock(&p->cmd_queue_lock);

      ast_mutex_lock(&p->sub->cx_queue_lock);
      for (q = p->sub->cx_queue; q; t = q->next, ast_free(q), q=t);
      p->sub->cx_queue = NULL;
      ast_mutex_unlock(&p->sub->cx_queue_lock);

      ast_mutex_lock(&p->sub->next->cx_queue_lock);
      for (q = p->sub->next->cx_queue; q; t = q->next, ast_free(q), q=t);
      p->sub->next->cx_queue = NULL;
      ast_mutex_unlock(&p->sub->next->cx_queue_lock);
   } else if (sub) {
      ast_mutex_lock(&sub->cx_queue_lock);
      for (q = sub->cx_queue; q; t = q->next, ast_free(q), q=t);
      sub->cx_queue = NULL;
      ast_mutex_unlock(&sub->cx_queue_lock);
   }
}


/*! \brief  find_command: (SC:) remove command transaction from queue */
static struct mgcp_request *find_command(struct mgcp_endpoint *p, struct mgcp_subchannel *sub,
      struct mgcp_request **queue, ast_mutex_t *l, int ident)
{
   struct mgcp_request *prev, *req;

   ast_mutex_lock(l);
   for (prev = NULL, req = *queue; req; prev = req, req = req->next) {
      if (req->trid == ident) {
         /* remove from queue */
         if (!prev)
            *queue = req->next;
         else
            prev->next = req->next;

         /* send next pending command */
         if (*queue) {
            ast_debug(1, "Posting Queued Request:\n%s to %s:%d\n", (*queue)->data,
               ast_inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));

            mgcp_postrequest(p, sub, (*queue)->data, (*queue)->len, (*queue)->trid);
         }
         break;
      }
   }
   ast_mutex_unlock(l);
   return req;
}

/* modified for new transport mechanism */
static void handle_response(struct mgcp_endpoint *p, struct mgcp_subchannel *sub,
      int result, unsigned int ident, struct mgcp_request *resp)
{
   char *c;
   struct mgcp_request *req;
   struct mgcp_gateway *gw = p->parent;

   if (result < 200) {
      /* provisional response */
      return;
   }

   if (p->slowsequence)
      req = find_command(p, sub, &p->cmd_queue, &p->cmd_queue_lock, ident);
   else if (sub)
      req = find_command(p, sub, &sub->cx_queue, &sub->cx_queue_lock, ident);
   else if (!(req = find_command(p, sub, &p->rqnt_queue, &p->rqnt_queue_lock, ident)))
      req = find_command(p, sub, &p->cmd_queue, &p->cmd_queue_lock, ident);

   if (!req) {
      ast_verb(3, "No command found on [%s] for transaction %d. Ignoring...\n",
            gw->name, ident);
      return;
   }

   if (p && (result >= 400) && (result <= 599)) {
      switch (result) {
      case 401:
         p->hookstate = MGCP_OFFHOOK;
         break;
      case 402:
         p->hookstate = MGCP_ONHOOK;
         break;
      case 406:
         ast_log(LOG_NOTICE, "Transaction %d timed out\n", ident);
         break;
      case 407:
         ast_log(LOG_NOTICE, "Transaction %d aborted\n", ident);
         break;
      }
      if (sub) {
         if (!sub->cxident[0] && (req->cmd == MGCP_CMD_CRCX)) {
             ast_log(LOG_NOTICE, "DLCX for all connections on %s due to error %d\n", gw->name, result);
             transmit_connection_del(sub);
         }
         if (sub->owner) {
            ast_log(LOG_NOTICE, "Terminating on result %d from %s@%s-%d\n",
               result, p->name, p->parent->name, sub ? sub->id:-1);
            mgcp_queue_hangup(sub);
         }
      } else {
         if (p->sub->next->owner) {
            ast_log(LOG_NOTICE, "Terminating on result %d from %s@%s-%d\n",
               result, p->name, p->parent->name, sub ? sub->id:-1);
            mgcp_queue_hangup(p->sub);
         }

         if (p->sub->owner) {
            ast_log(LOG_NOTICE, "Terminating on result %d from %s@%s-%d\n",
               result, p->name, p->parent->name, sub ? sub->id:-1);
            mgcp_queue_hangup(p->sub);
         }

         dump_cmd_queues(p, NULL);
      }
   }

   if (resp) {
      /* responseAck: */
      if (result == 200 && (req->cmd == MGCP_CMD_CRCX || req->cmd == MGCP_CMD_MDCX)) {
            if (sub) {
               transmit_response(sub, "000", resp, "OK");
               if (sub->owner && ast_channel_state(sub->owner) == AST_STATE_RINGING) {
                  ast_queue_control(sub->owner, AST_CONTROL_RINGING);
               }
            }
      }
      if (req->cmd == MGCP_CMD_CRCX) {
         if ((c = get_header(resp, "I"))) {
            if (!ast_strlen_zero(c) && sub) {
               /* if we are hanging up do not process this conn. */
               if (sub->owner) {
                  if (!ast_strlen_zero(sub->cxident)) {
                     if (strcasecmp(c, sub->cxident)) {
                        ast_log(LOG_WARNING, "Subchannel already has a cxident. sub->cxident: %s requested %s\n", sub->cxident, c);
                     }
                  }
                  ast_copy_string(sub->cxident, c, sizeof(sub->cxident));
                  if (sub->tmpdest.sin_addr.s_addr) {
                     transmit_modify_with_sdp(sub, NULL, 0);
                  }
               } else {
                  /* XXX delete this one
                     callid and conn id may already be lost.
                     so the following del conn may have a side effect of
                     cleaning up the next subchannel */
                  transmit_connection_del(sub);
               }
            }
         }
      }

      if (req->cmd == MGCP_CMD_AUEP) {
         /* check stale connection ids */
         if ((c = get_header(resp, "I"))) {
            char *v, *n;
            int len;
            while ((v = get_csv(c, &len, &n))) {
               if (len) {
                  if (strncasecmp(v, p->sub->cxident, len) &&
                      strncasecmp(v, p->sub->next->cxident, len)) {
                     /* connection id not found. delete it */
                     char cxident[80] = "";

                     if (len > (sizeof(cxident) - 1))
                        len = sizeof(cxident) - 1;
                     ast_copy_string(cxident, v, len);
                     ast_verb(3, "Non existing connection id %s on %s@%s \n",
                               cxident, p->name, gw->name);
                     transmit_connection_del_w_params(p, NULL, cxident);
                  }
               }
               c = n;
            }
         }

         /* Try to determine the hookstate returned from an audit endpoint command */
         if ((c = get_header(resp, "ES"))) {
            if (!ast_strlen_zero(c)) {
               if (strstr(c, "hu")) {
                  if (p->hookstate != MGCP_ONHOOK) {
                     /* XXX cleanup if we think we are offhook XXX */
                     if ((p->sub->owner || p->sub->next->owner ) &&
                         p->hookstate == MGCP_OFFHOOK)
                        mgcp_queue_hangup(sub);
                     p->hookstate = MGCP_ONHOOK;

                     /* update the requested events according to the new hookstate */
                     transmit_notify_request(p->sub, "");

                     ast_verb(3, "Setting hookstate of %s@%s to ONHOOK\n", p->name, gw->name);
                     }
               } else if (strstr(c, "hd")) {
                  if (p->hookstate != MGCP_OFFHOOK) {
                     p->hookstate = MGCP_OFFHOOK;

                     /* update the requested events according to the new hookstate */
                     transmit_notify_request(p->sub, "");

                     ast_verb(3, "Setting hookstate of %s@%s to OFFHOOK\n", p->name, gw->name);
                     }
                  }
               }
            }
         }

      if (resp && resp->lines) {
         /* do not process sdp if we are hanging up. this may be a late response */
         if (sub && sub->owner) {
            if (!sub->rtp)
               start_rtp(sub);
            if (sub->rtp)
               process_sdp(sub, resp);
         }
      }
   }

   ast_free(req);
}

static void start_rtp(struct mgcp_subchannel *sub)
{
   struct ast_sockaddr bindaddr_tmp;

   ast_mutex_lock(&sub->lock);
   /* check again to be on the safe side */
   if (sub->rtp) {
      ast_rtp_instance_destroy(sub->rtp);
      sub->rtp = NULL;
   }
   /* Allocate the RTP now */
   ast_sockaddr_from_sin(&bindaddr_tmp, &bindaddr);
   sub->rtp = ast_rtp_instance_new("asterisk", sched, &bindaddr_tmp, NULL);
   if (sub->rtp && sub->owner)
      ast_channel_set_fd(sub->owner, 0, ast_rtp_instance_fd(sub->rtp, 0));
   if (sub->rtp) {
      ast_rtp_instance_set_qos(sub->rtp, qos.tos_audio, qos.cos_audio, "MGCP RTP");
      ast_rtp_instance_set_prop(sub->rtp, AST_RTP_PROPERTY_NAT, sub->nat);
   }
   /* Make a call*ID */
   snprintf(sub->callid, sizeof(sub->callid), "%08lx%s", ast_random(), sub->txident);
   /* Transmit the connection create */
   if(!sub->parent->pktcgatealloc) {
      transmit_connect_with_sdp(sub, NULL);
   } else {
      transmit_connect(sub);
      sub->gate = NULL;
      if(!mgcp_alloc_pktcgate(sub))
         mgcp_queue_hangup(sub);
   }
   ast_mutex_unlock(&sub->lock);
}

static void *mgcp_ss(void *data)
{
   struct ast_channel *chan = data;
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(chan);
   struct mgcp_endpoint *p = sub->parent;
   /* char exten[AST_MAX_EXTENSION] = ""; */
   int len = 0;
   int timeout = firstdigittimeout;
   int res= 0;
   int getforward = 0;
   int loop_pause = 100;

   len = strlen(p->dtmf_buf);

   while (len < AST_MAX_EXTENSION - 1) {
      ast_debug(1, "Dtmf buffer '%s' for '%s@%s'\n", p->dtmf_buf, p->name, p->parent->name);
      res = 1;  /* Assume that we will get a digit */
      while (strlen(p->dtmf_buf) == len) {
         ast_safe_sleep(chan, loop_pause);
         timeout -= loop_pause;
         if (timeout <= 0){
            res = 0;
            break;
         }
         res = 1;
      }

      timeout = 0;
      len = strlen(p->dtmf_buf);

      if (!ast_ignore_pattern(ast_channel_context(chan), p->dtmf_buf)) {
         /*res = tone_zone_play_tone(p->subs[index].zfd, -1);*/
         ast_indicate(chan, -1);
      } else {
         /* XXX Redundant?  We should already be playing dialtone */
         /*tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALTONE);*/
         transmit_notify_request(sub, "L/dl");
      }
      if (ast_exists_extension(chan, ast_channel_context(chan), p->dtmf_buf, 1, p->cid_num)) {
         if (!res || !ast_matchmore_extension(chan, ast_channel_context(chan), p->dtmf_buf, 1, p->cid_num)) {
            if (getforward) {
               /* Record this as the forwarding extension */
               ast_copy_string(p->call_forward, p->dtmf_buf, sizeof(p->call_forward));
               ast_verb(3, "Setting call forward to '%s' on channel %s\n",
                     p->call_forward, ast_channel_name(chan));
               /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
               transmit_notify_request(sub, "L/sl");
               if (res)
                  break;
               usleep(500000);
               /*res = tone_zone_play_tone(p->subs[index].zfd, -1);*/
               ast_indicate(chan, -1);
               sleep(1);
               memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
               /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALTONE);*/
               transmit_notify_request(sub, "L/dl");
               len = 0;
               getforward = 0;
            } else {
               /*res = tone_zone_play_tone(p->subs[index].zfd, -1);*/
               ast_indicate(chan, -1);
               ast_channel_exten_set(chan, p->dtmf_buf);
               ast_channel_dialed(chan)->number.str = ast_strdup(p->dtmf_buf);
               memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
               ast_set_callerid(chan,
                  p->hidecallerid ? "" : p->cid_num,
                  p->hidecallerid ? "" : p->cid_name,
                  ast_channel_caller(chan)->ani.number.valid ? NULL : p->cid_num);
               ast_setstate(chan, AST_STATE_RING);
               /*dahdi_enable_ec(p);*/
               if (p->dtmfmode & MGCP_DTMF_HYBRID) {
                  p->dtmfmode |= MGCP_DTMF_INBAND;
                  ast_indicate(chan, -1);
               }
               res = ast_pbx_run(chan);
               if (res) {
                  ast_log(LOG_WARNING, "PBX exited non-zero\n");
                  /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_CONGESTION);*/
                  /*transmit_notify_request(p, "nbz", 1);*/
                  transmit_notify_request(sub, p->ncs ? "L/cg" : "G/cg");
               }
               return NULL;
            }
         } else {
            /* It's a match, but they just typed a digit, and there is an ambiguous match,
               so just set the timeout to matchdigittimeout and wait some more */
            timeout = matchdigittimeout;
         }
      } else if (res == 0) {
         ast_debug(1, "not enough digits (and no ambiguous match)...\n");
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_CONGESTION);*/
         transmit_notify_request(sub, p->ncs ? "L/cg" : "G/cg");
         /*dahdi_wait_event(p->subs[index].zfd);*/
         ast_hangup(chan);
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         return NULL;
      } else if (p->hascallwaiting && p->callwaiting && !strcmp(p->dtmf_buf, "*70")) {
         ast_verb(3, "Disabling call waiting on %s\n", ast_channel_name(chan));
         /* Disable call waiting if enabled */
         p->callwaiting = 0;
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         len = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         timeout = firstdigittimeout;
      } else if (!strcmp(p->dtmf_buf,ast_pickup_ext())) {
         /* Scan all channels and see if any there
          * ringing channqels with that have call groups
          * that equal this channels pickup group
          */
         if (ast_pickup_call(chan)) {
            ast_log(LOG_WARNING, "No call pickup possible...\n");
            /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_CONGESTION);*/
            transmit_notify_request(sub, p->ncs ? "L/cg" : "G/cg");
         }
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         ast_hangup(chan);
         return NULL;
      } else if (!p->hidecallerid && !strcmp(p->dtmf_buf, "*67")) {
         ast_verb(3, "Disabling Caller*ID on %s\n", ast_channel_name(chan));
         /* Disable Caller*ID if enabled */
         p->hidecallerid = 1;
         ast_set_callerid(chan, "", "", NULL);
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         len = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         timeout = firstdigittimeout;
      } else if (p->callreturn && !strcmp(p->dtmf_buf, "*69")) {
         res = 0;
         if (!ast_strlen_zero(p->lastcallerid)) {
            res = ast_say_digit_str(chan, p->lastcallerid, "", ast_channel_language(chan));
         }
         if (!res)
            /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
            transmit_notify_request(sub, "L/sl");
         break;
      } else if (!strcmp(p->dtmf_buf, "*78")) {
         /* Do not disturb */
         ast_verb(3, "Enabled DND on channel %s\n", ast_channel_name(chan));
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         p->dnd = 1;
         getforward = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         len = 0;
      } else if (!strcmp(p->dtmf_buf, "*79")) {
         /* Do not disturb */
         ast_verb(3, "Disabled DND on channel %s\n", ast_channel_name(chan));
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         p->dnd = 0;
         getforward = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         len = 0;
      } else if (p->cancallforward && !strcmp(p->dtmf_buf, "*72")) {
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         getforward = 1;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         len = 0;
      } else if (p->cancallforward && !strcmp(p->dtmf_buf, "*73")) {
         ast_verb(3, "Cancelling call forwarding on channel %s\n", ast_channel_name(chan));
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         memset(p->call_forward, 0, sizeof(p->call_forward));
         getforward = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         len = 0;
      } else if (ast_parking_ext_valid(p->dtmf_buf, chan, ast_channel_context(chan)) &&
         sub->next->owner && ast_bridged_channel(sub->next->owner)) {
         /* This is a three way call, the main call being a real channel,
            and we're parking the first call. */
         ast_masq_park_call_exten(ast_bridged_channel(sub->next->owner), chan,
            p->dtmf_buf, ast_channel_context(chan), 0, NULL);
         ast_verb(3, "Parking call to '%s'\n", ast_channel_name(chan));
         break;
      } else if (!ast_strlen_zero(p->lastcallerid) && !strcmp(p->dtmf_buf, "*60")) {
         ast_verb(3, "Blacklisting number %s\n", p->lastcallerid);
         res = ast_db_put("blacklist", p->lastcallerid, "1");
         if (!res) {
            /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
            transmit_notify_request(sub, "L/sl");
            memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
            len = 0;
         }
      } else if (p->hidecallerid && !strcmp(p->dtmf_buf, "*82")) {
         ast_verb(3, "Enabling Caller*ID on %s\n", ast_channel_name(chan));
         /* Enable Caller*ID if enabled */
         p->hidecallerid = 0;
         ast_set_callerid(chan, p->cid_num, p->cid_name, NULL);
         /*res = tone_zone_play_tone(p->subs[index].zfd, DAHDI_TONE_DIALRECALL);*/
         transmit_notify_request(sub, "L/sl");
         len = 0;
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         timeout = firstdigittimeout;
      } else if (!ast_canmatch_extension(chan, ast_channel_context(chan), p->dtmf_buf, 1,
         S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL))
         && ((p->dtmf_buf[0] != '*') || (strlen(p->dtmf_buf) > 2))) {
         ast_debug(1, "Can't match %s from '%s' in context %s\n", p->dtmf_buf,
            S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, "<Unknown Caller>"),
            ast_channel_context(chan));
         break;
      }
      if (!timeout)
         timeout = gendigittimeout;
      if (len && !ast_ignore_pattern(ast_channel_context(chan), p->dtmf_buf))
         /*tone_zone_play_tone(p->subs[index].zfd, -1);*/
         ast_indicate(chan, -1);
   }
#if 0
   for (;;) {
      res = ast_waitfordigit(chan, to);
      if (!res) {
         ast_debug(1, "Timeout...\n");
         break;
      }
      if (res < 0) {
         ast_debug(1, "Got hangup...\n");
         ast_hangup(chan);
         break;
      }
      exten[pos++] = res;
      if (!ast_ignore_pattern(chan->context, exten))
         ast_indicate(chan, -1);
      if (ast_matchmore_extension(chan, chan->context, exten, 1, chan->callerid)) {
         if (ast_exists_extension(chan, chan->context, exten, 1, chan->callerid))
            to = 3000;
         else
            to = 8000;
      } else
         break;
   }
   if (ast_exists_extension(chan, chan->context, exten, 1, chan->callerid)) {
      ast_copy_string(chan->exten, exten, sizeof(chan->exten)1);
      if (!p->rtp) {
         start_rtp(p);
      }
      ast_setstate(chan, AST_STATE_RING);
      chan->rings = 1;
      if (ast_pbx_run(chan)) {
         ast_log(LOG_WARNING, "Unable to launch PBX on %s\n", chan->name);
      } else {
         memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         return NULL;
      }
   }
#endif
   ast_hangup(chan);
   memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
   return NULL;
}

static int attempt_transfer(struct mgcp_endpoint *p)
{
   /* *************************
    * I hope this works.
    * Copied out of chan_zap
    * Cross your fingers
    * *************************/

   /* In order to transfer, we need at least one of the channels to
      actually be in a call bridge.  We can't conference two applications
      together (but then, why would we want to?) */
   if (ast_bridged_channel(p->sub->owner)) {
      /* The three-way person we're about to transfer to could still be in MOH, so
         stop if now if appropriate */
      if (ast_bridged_channel(p->sub->next->owner))
         ast_queue_control(p->sub->next->owner, AST_CONTROL_UNHOLD);
      if (ast_channel_state(p->sub->owner) == AST_STATE_RINGING) {
         ast_indicate(ast_bridged_channel(p->sub->next->owner), AST_CONTROL_RINGING);
      }
      if (ast_channel_masquerade(p->sub->next->owner, ast_bridged_channel(p->sub->owner))) {
         ast_log(LOG_WARNING, "Unable to masquerade %s as %s\n",
            ast_channel_name(ast_bridged_channel(p->sub->owner)), ast_channel_name(p->sub->next->owner));
         return -1;
      }
      /* Orphan the channel */
      unalloc_sub(p->sub->next);
   } else if (ast_bridged_channel(p->sub->next->owner)) {
      if (ast_channel_state(p->sub->owner) == AST_STATE_RINGING) {
         ast_indicate(ast_bridged_channel(p->sub->next->owner), AST_CONTROL_RINGING);
      }
      ast_queue_control(p->sub->next->owner, AST_CONTROL_UNHOLD);
      if (ast_channel_masquerade(p->sub->owner, ast_bridged_channel(p->sub->next->owner))) {
         ast_log(LOG_WARNING, "Unable to masquerade %s as %s\n",
            ast_channel_name(ast_bridged_channel(p->sub->next->owner)), ast_channel_name(p->sub->owner));
         return -1;
      }
      /*swap_subs(p, SUB_THREEWAY, SUB_REAL);*/
      ast_verb(3, "Swapping %d for %d on %s@%s\n", p->sub->id, p->sub->next->id, p->name, p->parent->name);
      p->sub = p->sub->next;
      unalloc_sub(p->sub->next);
      /* Tell the caller not to hangup */
      return 1;
   } else {
      ast_debug(1, "Neither %s nor %s are in a bridge, nothing to transfer\n",
         ast_channel_name(p->sub->owner), ast_channel_name(p->sub->next->owner));
      ast_channel_softhangup_internal_flag_add(p->sub->next->owner, AST_SOFTHANGUP_DEV);
      if (p->sub->next->owner) {
         p->sub->next->alreadygone = 1;
         mgcp_queue_hangup(p->sub->next);
      }
   }
   return 0;
}

static void handle_hd_hf(struct mgcp_subchannel *sub, char *ev)
{
   struct mgcp_endpoint *p = sub->parent;
   struct ast_channel *c;
   pthread_t t;

   /* Off hook / answer */
   if (sub->outgoing) {
      /* Answered */
      if (sub->owner) {
         if (ast_bridged_channel(sub->owner))
            ast_queue_control(sub->owner, AST_CONTROL_UNHOLD);
         sub->cxmode = MGCP_CX_SENDRECV;
         if (!sub->rtp) {
            start_rtp(sub);
         } else {
            transmit_modify_request(sub);
         }
         /*transmit_notify_request(sub, "aw");*/
         transmit_notify_request(sub, "");
         mgcp_queue_control(sub, AST_CONTROL_ANSWER);
      }
   } else {
      /* Start switch */
      /*sub->cxmode = MGCP_CX_SENDRECV;*/
      if (!sub->owner) {
         if (!sub->rtp) {
            start_rtp(sub);
         } else {
            transmit_modify_request(sub);
         }
         if (p->immediate) {
            /* The channel is immediately up. Start right away */
#ifdef DLINK_BUGGY_FIRMWARE
            transmit_notify_request(sub, "rt");
#else
            transmit_notify_request(sub, p->ncs ? "L/rt" : "G/rt");
#endif
            c = mgcp_new(sub, AST_STATE_RING, NULL);
            if (!c) {
               ast_log(LOG_WARNING, "Unable to start PBX on channel %s@%s\n", p->name, p->parent->name);
               transmit_notify_request(sub, p->ncs ? "L/cg" : "G/cg");
               ast_hangup(c);
            }
         } else {
            if (has_voicemail(p)) {
               transmit_notify_request(sub, "L/sl");
            } else {
               transmit_notify_request(sub, "L/dl");
            }
            c = mgcp_new(sub, AST_STATE_DOWN, NULL);
            if (c) {
               if (ast_pthread_create_detached(&t, NULL, mgcp_ss, c)) {
                  ast_log(LOG_WARNING, "Unable to create switch thread: %s\n", strerror(errno));
                  ast_hangup(c);
               }
            } else {
               ast_log(LOG_WARNING, "Unable to create channel for %s@%s\n", p->name, p->parent->name);
            }
         }
      } else {
         if (p->hookstate == MGCP_OFFHOOK) {
            ast_log(LOG_WARNING, "Off hook, but already have owner on %s@%s\n", p->name, p->parent->name);
         } else {
            ast_log(LOG_WARNING, "On hook, but already have owner on %s@%s\n", p->name, p->parent->name);
            ast_log(LOG_WARNING, "If we're onhook why are we here trying to handle a hd or hf?\n");
         }
         if (ast_bridged_channel(sub->owner))
            ast_queue_control(sub->owner, AST_CONTROL_UNHOLD);
         sub->cxmode = MGCP_CX_SENDRECV;
         if (!sub->rtp) {
            start_rtp(sub);
         } else {
            transmit_modify_request(sub);
         }
         /*transmit_notify_request(sub, "aw");*/
         transmit_notify_request(sub, "");
         /*ast_queue_control(sub->owner, AST_CONTROL_ANSWER);*/
      }
   }
}

static int handle_request(struct mgcp_subchannel *sub, struct mgcp_request *req, struct sockaddr_in *sin)
{
   char *ev, *s;
   struct ast_frame f = { 0, };
   struct mgcp_endpoint *p = sub->parent;
   struct mgcp_gateway *g = NULL;
   int res;

   ast_debug(1, "Handling request '%s' on %s@%s\n", req->verb, p->name, p->parent->name);
   /* Clear out potential response */
   if (!strcasecmp(req->verb, "RSIP")) {
      /* Test if this RSIP request is just a keepalive */
      if (!strcasecmp( get_header(req, "RM"), "X-keepalive")) {
         ast_verb(3, "Received keepalive request from %s@%s\n", p->name, p->parent->name);
         transmit_response(sub, "200", req, "OK");
      } else {
         dump_queue(p->parent, p);
         dump_cmd_queues(p, NULL);

         if ((strcmp(p->name, p->parent->wcardep) != 0)) {
            ast_verb(3, "Resetting interface %s@%s\n", p->name, p->parent->name);
         }
         /* For RSIP on wildcard we reset all endpoints */
         if (!strcmp(p->name, p->parent->wcardep)) {
            /* Reset all endpoints */
            struct mgcp_endpoint *tmp_ep;

            g = p->parent;
            for (tmp_ep = g->endpoints; tmp_ep; tmp_ep = tmp_ep->next) {
               /*if ((strcmp(tmp_ep->name, "*") != 0) && (strcmp(tmp_ep->name, "aaln/" "*") != 0)) {*/
               if (strcmp(tmp_ep->name, g->wcardep) != 0) {
                  struct mgcp_subchannel *tmp_sub, *first_sub;
                  ast_verb(3, "Resetting interface %s@%s\n", tmp_ep->name, p->parent->name);

                  first_sub = tmp_ep->sub;
                  tmp_sub = tmp_ep->sub;
                  while (tmp_sub) {
                     mgcp_queue_hangup(tmp_sub);
                     tmp_sub = tmp_sub->next;
                     if (tmp_sub == first_sub)
                        break;
                  }
               }
            }
         } else if (sub->owner) {
            mgcp_queue_hangup(sub);
         }
         transmit_response(sub, "200", req, "OK");
         /* We don't send NTFY or AUEP to wildcard ep */
         if (strcmp(p->name, p->parent->wcardep) != 0) {
            transmit_notify_request(sub, "");
            /* Audit endpoint.
             Idea is to prevent lost lines due to race conditions
            */
            transmit_audit_endpoint(p);
         }
      }
   } else if (!strcasecmp(req->verb, "NTFY")) {
      /* Acknowledge and be sure we keep looking for the same things */
      transmit_response(sub, "200", req, "OK");
      /* Notified of an event */
      ev = get_header(req, "O");
      s = strchr(ev, '/');
      if (s) ev = s + 1;
      ast_debug(1, "Endpoint '%s@%s-%d' observed '%s'\n", p->name, p->parent->name, sub->id, ev);
      /* Keep looking for events unless this was a hangup */
      if (strcasecmp(ev, "hu") && strcasecmp(ev, "hd") && strcasecmp(ev, "ping")) {
         transmit_notify_request(sub, p->curtone);
      }
      if (!strcasecmp(ev, "hd")) {
         p->hookstate = MGCP_OFFHOOK;
         sub->cxmode = MGCP_CX_SENDRECV;

         if (p) {
           /* When the endpoint have a Off hook transition we allways
              starts without any previous dtmfs */
           memset(p->dtmf_buf, 0, sizeof(p->dtmf_buf));
         }

         handle_hd_hf(sub, ev);
      } else if (!strcasecmp(ev, "hf")) {
         /* We can assume we are offhook if we received a hookflash */
         /* First let's just do call wait and ignore threeway */
         /* We're currently in charge */
         if (p->hookstate != MGCP_OFFHOOK) {
            /* Cisco c7940 sends hf even if the phone is onhook */
            /* Thanks to point on IRC for pointing this out */
            return -1;
         }
         /* do not let * conference two down channels */
         if (sub->owner && ast_channel_state(sub->owner) == AST_STATE_DOWN && !sub->next->owner)
            return -1;

         if (p->callwaiting || p->transfer || p->threewaycalling) {
            ast_verb(3, "Swapping %d for %d on %s@%s\n", p->sub->id, p->sub->next->id, p->name, p->parent->name);
            p->sub = p->sub->next;

            /* transfer control to our next subchannel */
            if (!sub->next->owner) {
               /* plave the first call on hold and start up a new call */
               sub->cxmode = MGCP_CX_MUTE;
               ast_verb(3, "MGCP Muting %d on %s@%s\n", sub->id, p->name, p->parent->name);
               transmit_modify_request(sub);
               if (sub->owner && ast_bridged_channel(sub->owner))
                  ast_queue_control(sub->owner, AST_CONTROL_HOLD);
               sub->next->cxmode = MGCP_CX_RECVONLY;
               handle_hd_hf(sub->next, ev);
            } else if (sub->owner && sub->next->owner) {
               /* We've got two active calls lets decide whether or not to conference or just flip flop */
               if ((!sub->outgoing) && (!sub->next->outgoing)) {
                  /* We made both calls lets conferenct */
                  ast_verb(3, "MGCP Conferencing %d and %d on %s@%s\n",
                        sub->id, sub->next->id, p->name, p->parent->name);
                  sub->cxmode = MGCP_CX_CONF;
                  sub->next->cxmode = MGCP_CX_CONF;
                  if (ast_bridged_channel(sub->next->owner))
                     ast_queue_control(sub->next->owner, AST_CONTROL_UNHOLD);
                  transmit_modify_request(sub);
                  transmit_modify_request(sub->next);
               } else {
                  /* Let's flipflop between calls */
                  /* XXX Need to check for state up ??? */
                  /* XXX Need a way to indicate the current call, or maybe the call that's waiting */
                  ast_verb(3, "We didn't make one of the calls FLIPFLOP %d and %d on %s@%s\n",
                        sub->id, sub->next->id, p->name, p->parent->name);
                  sub->cxmode = MGCP_CX_MUTE;
                  ast_verb(3, "MGCP Muting %d on %s@%s\n", sub->id, p->name, p->parent->name);
                  transmit_modify_request(sub);
                  if (ast_bridged_channel(sub->owner))
                     ast_queue_control(sub->owner, AST_CONTROL_HOLD);

                  if (ast_bridged_channel(sub->next->owner))
                     ast_queue_control(sub->next->owner, AST_CONTROL_HOLD);

                  handle_hd_hf(sub->next, ev);
               }
            } else {
               /* We've most likely lost one of our calls find an active call and bring it up */
               if (sub->owner) {
                  p->sub = sub;
               } else if (sub->next->owner) {
                  p->sub = sub->next;
               } else {
                  /* We seem to have lost both our calls */
                  /* XXX - What do we do now? */
                  return -1;
               }
               if (ast_bridged_channel(p->sub->owner))
                  ast_queue_control(p->sub->owner, AST_CONTROL_UNHOLD);
               p->sub->cxmode = MGCP_CX_SENDRECV;
               transmit_modify_request(p->sub);
            }
         } else {
            ast_log(LOG_WARNING, "Callwaiting, call transfer or threeway calling not enabled on endpoint %s@%s\n",
               p->name, p->parent->name);
         }
      } else if (!strcasecmp(ev, "hu")) {
         p->hookstate = MGCP_ONHOOK;
         sub->cxmode = MGCP_CX_RECVONLY;
         ast_debug(1, "MGCP %s@%s Went on hook\n", p->name, p->parent->name);
         /* Do we need to send MDCX before a DLCX ?
         if (sub->rtp) {
            transmit_modify_request(sub);
         }
         */
         if (p->transfer && (sub->owner && sub->next->owner) && ((!sub->outgoing) || (!sub->next->outgoing))) {
            /* We're allowed to transfer, we have two avtive calls and */
            /* we made at least one of the calls.  Let's try and transfer */
            ast_mutex_lock(&p->sub->next->lock);
            res = attempt_transfer(p);
            if (res < 0) {
               if (p->sub->next->owner) {
                  sub->next->alreadygone = 1;
                  mgcp_queue_hangup(sub->next);
               }
            } else if (res) {
               ast_log(LOG_WARNING, "Transfer attempt failed\n");
               ast_mutex_unlock(&p->sub->next->lock);
               return -1;
            }
            ast_mutex_unlock(&p->sub->next->lock);
         } else {
            /* Hangup the current call */
            /* If there is another active call, mgcp_hangup will ring the phone with the other call */
            if (sub->owner) {
               sub->alreadygone = 1;
               mgcp_queue_hangup(sub);
            } else {
               ast_verb(3, "MGCP handle_request(%s@%s-%d) ast_channel already destroyed, resending DLCX.\n",
                     p->name, p->parent->name, sub->id);
               /* Instruct the other side to remove the connection since it apparently *
                * still thinks the channel is active. *
                * For Cisco IAD2421 /BAK/ */
               transmit_connection_del(sub);
            }
         }
         if ((p->hookstate == MGCP_ONHOOK) && (!sub->rtp) && (!sub->next->rtp)) {
            p->hidecallerid = 0;
            if (p->hascallwaiting && !p->callwaiting) {
               ast_verb(3, "Enabling call waiting on MGCP/%s@%s-%d\n", p->name, p->parent->name, sub->id);
               p->callwaiting = -1;
            }
            if (has_voicemail(p)) {
               ast_verb(3, "MGCP handle_request(%s@%s) set vmwi(+)\n", p->name, p->parent->name);
               transmit_notify_request(sub, "L/vmwi(+)");
            } else {
               ast_verb(3, "MGCP handle_request(%s@%s) set vmwi(-)\n", p->name, p->parent->name);
               transmit_notify_request(sub, "L/vmwi(-)");
            }
         }
      } else if ((strlen(ev) == 1) &&
            (((ev[0] >= '0') && (ev[0] <= '9')) ||
             ((ev[0] >= 'A') && (ev[0] <= 'D')) ||
              (ev[0] == '*') || (ev[0] == '#'))) {
         if (sub && sub->owner && (ast_channel_state(sub->owner) >=  AST_STATE_UP)) {
            f.frametype = AST_FRAME_DTMF;
            f.subclass.integer = ev[0];
            f.src = "mgcp";
            /* XXX MUST queue this frame to all subs in threeway call if threeway call is active */
            mgcp_queue_frame(sub, &f);
            ast_mutex_lock(&sub->next->lock);
            if (sub->next->owner)
               mgcp_queue_frame(sub->next, &f);
            ast_mutex_unlock(&sub->next->lock);
            if (strstr(p->curtone, (p->ncs ? "wt1" : "wt")) && (ev[0] == 'A')) {
               memset(p->curtone, 0, sizeof(p->curtone));
            }
         } else {
            p->dtmf_buf[strlen(p->dtmf_buf)] = ev[0];
            p->dtmf_buf[strlen(p->dtmf_buf)] = '\0';
         }
      } else if (!strcasecmp(ev, "T")) {
         /* Digit timeout -- unimportant */
      } else if (!strcasecmp(ev, "ping")) {
         /* ping -- unimportant */
      } else {
         ast_log(LOG_NOTICE, "Received unknown event '%s' from %s@%s\n", ev, p->name, p->parent->name);
      }
   } else {
      ast_log(LOG_WARNING, "Unknown verb '%s' received from %s\n", req->verb, ast_inet_ntoa(sin->sin_addr));
      transmit_response(sub, "510", req, "Unknown verb");
   }
   return 0;
}

static int find_and_retrans(struct mgcp_subchannel *sub, struct mgcp_request *req)
{
   int seqno=0;
   time_t now;
   struct mgcp_response *prev = NULL, *cur, *next, *answer = NULL;
   time(&now);
   if (sscanf(req->identifier, "%30d", &seqno) != 1) {
      seqno = 0;
   }
   for (cur = sub->parent->parent->responses, next = cur ? cur->next : NULL; cur; cur = next, next = cur ? cur->next : NULL) {
      if (now - cur->whensent > RESPONSE_TIMEOUT) {
         /* Delete this entry */
         if (prev)
            prev->next = next;
         else
            sub->parent->parent->responses = next;
         ast_free(cur);
      } else {
         if (seqno == cur->seqno)
            answer = cur;
         prev = cur;
      }
   }
   if (answer) {
      resend_response(sub, answer);
      return 1;
   }
   return 0;
}

static int mgcpsock_read(int *id, int fd, short events, void *ignore)
{
   struct mgcp_request req;
   struct sockaddr_in sin;
   struct mgcp_subchannel *sub;
   int res;
   socklen_t len;
   int result;
   int ident;
   len = sizeof(sin);
   memset(&req, 0, sizeof(req));
   res = recvfrom(mgcpsock, req.data, sizeof(req.data) - 1, 0, (struct sockaddr *)&sin, &len);
   if (res < 0) {
      if (errno != ECONNREFUSED)
         ast_log(LOG_WARNING, "Recv error: %s\n", strerror(errno));
      return 1;
   }
   req.data[res] = '\0';
   req.len = res;
   ast_debug(1, "MGCP read: \n%s\nfrom %s:%d\n", req.data, ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
   parse(&req);
   if (req.headers < 1) {
      /* Must have at least one header */
      return 1;
   }
   if (ast_strlen_zero(req.identifier)) {
      ast_log(LOG_NOTICE, "Message from %s missing identifier\n", ast_inet_ntoa(sin.sin_addr));
      return 1;
   }

   if (sscanf(req.verb, "%30d", &result) && sscanf(req.identifier, "%30d", &ident)) {
      if (result < 200) {
         ast_debug(1, "Ignoring provisional response on transaction %d\n", ident);
         return 1;
      }
      /* Try to find who this message is for, if it's important */
      sub = find_subchannel_and_lock(NULL, ident, &sin);
      if (sub) {
         struct mgcp_gateway *gw = sub->parent->parent;
         struct mgcp_message *cur, *prev;

         ast_mutex_unlock(&sub->lock);
         ast_mutex_lock(&gw->msgs_lock);
         for (prev = NULL, cur = gw->msgs; cur; prev = cur, cur = cur->next) {
            if (cur->seqno == ident) {
               ast_debug(1, "Got response back on transaction %d\n", ident);
               if (prev)
                  prev->next = cur->next;
               else
                  gw->msgs = cur->next;
               break;
            }
         }

         /* stop retrans timer if the queue is empty */
         if (!gw->msgs) {
            AST_SCHED_DEL(sched, gw->retransid);
         }

         ast_mutex_unlock(&gw->msgs_lock);
         if (cur) {
            handle_response(cur->owner_ep, cur->owner_sub, result, ident, &req);
            ast_free(cur);
            return 1;
         }

         ast_log(LOG_NOTICE, "Got response back on [%s] for transaction %d we aren't sending?\n",
            gw->name, ident);
      }
   } else {
      if (ast_strlen_zero(req.endpoint) ||
         ast_strlen_zero(req.version) ||
         ast_strlen_zero(req.verb)) {
         ast_log(LOG_NOTICE, "Message must have a verb, an idenitifier, version, and endpoint\n");
         return 1;
      }
      /* Process request, with iflock held */
      sub = find_subchannel_and_lock(req.endpoint, 0, &sin);
      if (sub) {
         /* look first to find a matching response in the queue */
         if (!find_and_retrans(sub, &req))
            /* pass the request off to the currently mastering subchannel */
            handle_request(sub, &req, &sin);
         ast_mutex_unlock(&sub->lock);
      }
   }
   return 1;
}

static int *mgcpsock_read_id = NULL;

static int mgcp_prune_realtime_gateway(struct mgcp_gateway *g)
{
   struct mgcp_endpoint *enext, *e;
   struct mgcp_subchannel *s, *sub;
   int i, prune = 1;

   if (g->ha || !g->realtime || ast_mutex_trylock(&g->msgs_lock) || g->msgs) {
      ast_mutex_unlock(&g->msgs_lock);
      return 0;
   }

   for (e = g->endpoints; e; e = e->next) {
      ast_mutex_lock(&e->lock);
      if (e->dsp || ast_mutex_trylock(&e->rqnt_queue_lock) || ast_mutex_trylock(&e->cmd_queue_lock)) {
         prune = 0;
      } else if (e->rqnt_queue || e->cmd_queue) {
         prune = 0;
      }
      s = e->sub;
      for (i = 0; (i < MAX_SUBS) && s; i++) {
         ast_mutex_lock(&s->lock);
         if (!ast_strlen_zero(s->cxident) || s->rtp || ast_mutex_trylock(&s->cx_queue_lock) || s->gate) {
            prune = 0;
         } else if (s->cx_queue) {
            prune = 0;
         }
         s = s->next;
      }
   }

   for (e = g->endpoints, sub = e->sub, enext = e->next; e; e = enext, enext = e->next) {
      for (i = 0; (i < MAX_SUBS) && sub; i++) {
         s = sub;
         sub = sub->next;
         ast_mutex_unlock(&s->lock);
         ast_mutex_unlock(&s->cx_queue_lock);
         if (prune) {
            ast_mutex_destroy(&s->lock);
            ast_mutex_destroy(&s->cx_queue_lock);
            free(s);
         }
      }
      ast_mutex_unlock(&e->lock);
      ast_mutex_unlock(&e->rqnt_queue_lock);
      ast_mutex_unlock(&e->cmd_queue_lock);
      if (prune) {
         ast_mutex_destroy(&e->lock);
         ast_mutex_destroy(&e->rqnt_queue_lock);
         ast_mutex_destroy(&e->cmd_queue_lock);
         free(e);
      }
   }
   if (prune) {
      ast_debug(1, "***** MGCP REALTIME PRUNE GW: %s\n", g->name);
   }
   return prune;
}

static void *do_monitor(void *data)
{
   int res;
   int reloading;
   struct mgcp_gateway *g, *gprev;
   /*struct mgcp_gateway *g;*/
   /*struct mgcp_endpoint *e;*/
   /*time_t thispass = 0, lastpass = 0;*/
   time_t lastrun = 0;

   /* Add an I/O event to our UDP socket */
   if (mgcpsock > -1) {
      mgcpsock_read_id = ast_io_add(io, mgcpsock, mgcpsock_read, AST_IO_IN, NULL);
   }
   /* This thread monitors all the frame relay interfaces which are not yet in use
      (and thus do not have a separate thread) indefinitely */
   /* From here on out, we die whenever asked */
   for (;;) {
      /* Check for a reload request */
      ast_mutex_lock(&mgcp_reload_lock);
      reloading = mgcp_reloading;
      mgcp_reloading = 0;
      ast_mutex_unlock(&mgcp_reload_lock);
      if (reloading) {
         ast_verb(1, "Reloading MGCP\n");
         reload_config(1);
         /* Add an I/O event to our UDP socket */
         if (mgcpsock > -1 && !mgcpsock_read_id) {
            mgcpsock_read_id = ast_io_add(io, mgcpsock, mgcpsock_read, AST_IO_IN, NULL);
         }
      }

      /* Check for interfaces needing to be killed */
      /* Don't let anybody kill us right away.  Nobody should lock the interface list
         and wait for the monitor list, but the other way around is okay. */
      ast_mutex_lock(&monlock);
      /* Lock the network interface */
      ast_mutex_lock(&netlock);

#if 0
      /* XXX THIS IS COMPLETELY HOSED */
      /* The gateway goes into a state of panic */
      /* If the vmwi indicator is sent while it is reseting interfaces */
      lastpass = thispass;
      thispass = time(NULL);
      g = gateways;
      while(g) {
         if (thispass != lastpass) {
            e = g->endpoints;
            while(e) {
               if (e->type == TYPE_LINE) {
                  res = has_voicemail(e);
                  if ((e->msgstate != res) && (e->hookstate == MGCP_ONHOOK) && (!e->rtp)){
                     if (res) {
                        transmit_notify_request(e, "L/vmwi(+)");
                     } else {
                        transmit_notify_request(e, "L/vmwi(-)");
                     }
                     e->msgstate = res;
                     e->onhooktime = thispass;
                  }
               }
               e = e->next;
            }
         }
         g = g->next;
      }
#endif
      /* pruning unused realtime gateways, running in every 60 seconds*/
      if(time(NULL) > (lastrun + 60)) {
         ast_mutex_lock(&gatelock);
         g = gateways;
         gprev = NULL;
         while(g) {
            if(g->realtime) {
               if(mgcp_prune_realtime_gateway(g)) {
                  if(gprev) {
                     gprev->next = g->next;
                  } else {
                     gateways = g->next;
                  }
                  ast_mutex_unlock(&g->msgs_lock);
                  ast_mutex_destroy(&g->msgs_lock);
                  free(g);
               } else {
                  ast_mutex_unlock(&g->msgs_lock);
                  gprev = g;
               }
            } else {
               gprev = g;
            }
            g = g->next;
         }
         ast_mutex_unlock(&gatelock);
         lastrun = time(NULL);
      }
      /* Okay, now that we know what to do, release the network lock */
      ast_mutex_unlock(&netlock);
      /* And from now on, we're okay to be killed, so release the monitor lock as well */
      ast_mutex_unlock(&monlock);
      pthread_testcancel();
      /* Wait for sched or io */
      res = ast_sched_wait(sched);
      /* copied from chan_sip.c */
      if ((res < 0) || (res > 1000)) {
         res = 1000;
      }
      res = ast_io_wait(io, res);
      ast_mutex_lock(&monlock);
      if (res >= 0) {
         ast_sched_runq(sched);
      }
      ast_mutex_unlock(&monlock);
   }
   /* Never reached */
   return NULL;
}

static int restart_monitor(void)
{
   /* If we're supposed to be stopped -- stay stopped */
   if (monitor_thread == AST_PTHREADT_STOP)
      return 0;
   if (ast_mutex_lock(&monlock)) {
      ast_log(LOG_WARNING, "Unable to lock monitor\n");
      return -1;
   }
   if (monitor_thread == pthread_self()) {
      ast_mutex_unlock(&monlock);
      ast_log(LOG_WARNING, "Cannot kill myself\n");
      return -1;
   }
   if (monitor_thread != AST_PTHREADT_NULL) {
      /* Wake up the thread */
      pthread_kill(monitor_thread, SIGURG);
   } else {
      /* Start a new monitor */
      if (ast_pthread_create_background(&monitor_thread, NULL, do_monitor, NULL) < 0) {
         ast_mutex_unlock(&monlock);
         ast_log(LOG_ERROR, "Unable to start monitor thread.\n");
         return -1;
      }
   }
   ast_mutex_unlock(&monlock);
   return 0;
}

static struct ast_channel *mgcp_request(const char *type, struct ast_format_cap *cap, const struct ast_channel *requestor, const char *dest, int *cause)
{
   struct mgcp_subchannel *sub;
   struct ast_channel *tmpc = NULL;
   char tmp[256];

   if (!(ast_format_cap_has_joint(cap, global_capability))) {
      ast_log(LOG_NOTICE, "Asked to get a channel of unsupported format '%s'\n", ast_getformatname_multiple(tmp, sizeof(tmp), cap));
      /*return NULL;*/
   }
   ast_copy_string(tmp, dest, sizeof(tmp));
   if (ast_strlen_zero(tmp)) {
      ast_log(LOG_NOTICE, "MGCP Channels require an endpoint\n");
      return NULL;
   }
   if (!(sub = find_subchannel_and_lock(tmp, 0, NULL))) {
      ast_log(LOG_WARNING, "Unable to find MGCP endpoint '%s'\n", tmp);
      *cause = AST_CAUSE_UNREGISTERED;
      return NULL;
   }

   ast_verb(3, "MGCP mgcp_request(%s)\n", tmp);
   ast_verb(3, "MGCP cw: %d, dnd: %d, so: %d, sno: %d\n",
         sub->parent->callwaiting, sub->parent->dnd, sub->owner ? 1 : 0, sub->next->owner ? 1: 0);
   /* Must be busy */
   if (((sub->parent->callwaiting) && ((sub->owner) && (sub->next->owner))) ||
      ((!sub->parent->callwaiting) && (sub->owner)) ||
       (sub->parent->dnd && (ast_strlen_zero(sub->parent->call_forward)))) {
      if (sub->parent->hookstate == MGCP_ONHOOK) {
         if (has_voicemail(sub->parent)) {
            transmit_notify_request(sub,"L/vmwi(+)");
         } else {
            transmit_notify_request(sub,"L/vmwi(-)");
         }
      }
      *cause = AST_CAUSE_BUSY;
      ast_mutex_unlock(&sub->lock);
      return NULL;
   }
   tmpc = mgcp_new(sub->owner ? sub->next : sub, AST_STATE_DOWN, requestor ? ast_channel_linkedid(requestor) : NULL);
   ast_mutex_unlock(&sub->lock);
   if (!tmpc)
      ast_log(LOG_WARNING, "Unable to make channel for '%s'\n", tmp);
   restart_monitor();
   return tmpc;
}

/* modified for reload support */
/*! \brief  build_gateway: parse mgcp.conf and create gateway/endpoint structures */
static struct mgcp_gateway *build_gateway(char *cat, struct ast_variable *v)
{
   struct mgcp_gateway *gw;
   struct mgcp_endpoint *e;
   struct mgcp_subchannel *sub;
   struct ast_variable *chanvars = NULL;

   /*char txident[80];*/
   int i=0, y=0;
   int gw_reload = 0;
   int ep_reload = 0;
   directmedia = DIRECTMEDIA;

   /* locate existing gateway */
   for (gw = gateways; gw; gw = gw->next) {
      if (!strcasecmp(cat, gw->name)) {
         /* gateway already exists */
         gw->delme = 0;
         gw_reload = 1;
         break;
      }
   }

   if (!gw && !(gw = ast_calloc(1, sizeof(*gw)))) {
      return NULL;
   }

   if (!gw_reload) {
      gw->expire = -1;
      gw->realtime = 0;
      gw->retransid = -1;
      ast_mutex_init(&gw->msgs_lock);
      ast_copy_string(gw->name, cat, sizeof(gw->name));
      /* check if the name is numeric ip */
      if ((strchr(gw->name, '.')) && inet_addr(gw->name) != INADDR_NONE)
         gw->isnamedottedip = 1;
   }
   for (; v; v = v->next) {
      if (!strcasecmp(v->name, "host")) {
         if (!strcasecmp(v->value, "dynamic")) {
            /* They'll register with us */
            gw->dynamic = 1;
            memset(&gw->addr.sin_addr, 0, 4);
            if (gw->addr.sin_port) {
               /* If we've already got a port, make it the default rather than absolute */
               gw->defaddr.sin_port = gw->addr.sin_port;
               gw->addr.sin_port = 0;
            }
         } else {
            /* Non-dynamic.  Make sure we become that way if we're not */
            AST_SCHED_DEL(sched, gw->expire);
            gw->dynamic = 0;
            {
               struct ast_sockaddr tmp;

               ast_sockaddr_from_sin(&tmp, &gw->addr);
               if (ast_get_ip(&tmp, v->value)) {
                  if (!gw_reload) {
                     ast_mutex_destroy(&gw->msgs_lock);
                     ast_free(gw);
                  }
                  return NULL;
               }
               ast_sockaddr_to_sin(&tmp, &gw->addr);
            }
         }
      } else if (!strcasecmp(v->name, "defaultip")) {
         struct ast_sockaddr tmp;

         ast_sockaddr_from_sin(&tmp, &gw->defaddr);
         if (ast_get_ip(&tmp, v->value)) {
            if (!gw_reload) {
               ast_mutex_destroy(&gw->msgs_lock);
               ast_free(gw);
            }
            return NULL;
         }
         ast_sockaddr_to_sin(&tmp, &gw->defaddr);
      } else if (!strcasecmp(v->name, "permit") ||
         !strcasecmp(v->name, "deny")) {
         gw->ha = ast_append_ha(v->name, v->value, gw->ha, NULL);
      } else if (!strcasecmp(v->name, "port")) {
         gw->addr.sin_port = htons(atoi(v->value));
      } else if (!strcasecmp(v->name, "context")) {
         ast_copy_string(context, v->value, sizeof(context));
      } else if (!strcasecmp(v->name, "dtmfmode")) {
         if (!strcasecmp(v->value, "inband"))
            dtmfmode = MGCP_DTMF_INBAND;
         else if (!strcasecmp(v->value, "rfc2833"))
            dtmfmode = MGCP_DTMF_RFC2833;
         else if (!strcasecmp(v->value, "hybrid"))
            dtmfmode = MGCP_DTMF_HYBRID;
         else if (!strcasecmp(v->value, "none"))
            dtmfmode = 0;
         else
            ast_log(LOG_WARNING, "'%s' is not a valid DTMF mode at line %d\n", v->value, v->lineno);
      } else if (!strcasecmp(v->name, "nat")) {
         nat = ast_true(v->value);
      } else if (!strcasecmp(v->name, "ncs")) {
         ncs = ast_true(v->value);
      } else if (!strcasecmp(v->name, "hangupongateremove")) {
         hangupongateremove = ast_true(v->value);
      } else if (!strcasecmp(v->name, "pktcgatealloc")) {
         pktcgatealloc = ast_true(v->value);
      } else if (!strcasecmp(v->name, "callerid")) {
         if (!strcasecmp(v->value, "asreceived")) {
            cid_num[0] = '\0';
            cid_name[0] = '\0';
         } else {
            ast_callerid_split(v->value, cid_name, sizeof(cid_name), cid_num, sizeof(cid_num));
         }
      } else if (!strcasecmp(v->name, "language")) {
         ast_copy_string(language, v->value, sizeof(language));
      } else if (!strcasecmp(v->name, "accountcode")) {
         ast_copy_string(accountcode, v->value, sizeof(accountcode));
      } else if (!strcasecmp(v->name, "amaflags")) {
         y = ast_cdr_amaflags2int(v->value);
         if (y < 0) {
            ast_log(LOG_WARNING, "Invalid AMA flags: %s at line %d\n", v->value, v->lineno);
         } else {
            amaflags = y;
         }
      } else if (!strcasecmp(v->name, "setvar")) {
         chanvars = add_var(v->value, chanvars);
      } else if (!strcasecmp(v->name, "clearvars")) {
         if (chanvars) {
            ast_variables_destroy(chanvars);
            chanvars = NULL;
         }
      } else if (!strcasecmp(v->name, "musiconhold")) {
         ast_copy_string(musicclass, v->value, sizeof(musicclass));
      } else if (!strcasecmp(v->name, "parkinglot")) {
         ast_copy_string(parkinglot, v->value, sizeof(parkinglot));
      } else if (!strcasecmp(v->name, "callgroup")) {
         cur_callergroup = ast_get_group(v->value);
      } else if (!strcasecmp(v->name, "pickupgroup")) {
         cur_pickupgroup = ast_get_group(v->value);
      } else if (!strcasecmp(v->name, "immediate")) {
         immediate = ast_true(v->value);
      } else if (!strcasecmp(v->name, "cancallforward")) {
         cancallforward = ast_true(v->value);
      } else if (!strcasecmp(v->name, "singlepath")) {
         singlepath = ast_true(v->value);
      } else if (!strcasecmp(v->name, "directmedia") || !strcasecmp(v->name, "canreinvite")) {
         directmedia = ast_true(v->value);
      } else if (!strcasecmp(v->name, "mailbox")) {
         ast_copy_string(mailbox, v->value, sizeof(mailbox));
      } else if (!strcasecmp(v->name, "hasvoicemail")) {
         if (ast_true(v->value) && ast_strlen_zero(mailbox)) {
            ast_copy_string(mailbox, gw->name, sizeof(mailbox));
         }
      } else if (!strcasecmp(v->name, "adsi")) {
         adsi = ast_true(v->value);
      } else if (!strcasecmp(v->name, "callreturn")) {
         callreturn = ast_true(v->value);
      } else if (!strcasecmp(v->name, "callwaiting")) {
         callwaiting = ast_true(v->value);
      } else if (!strcasecmp(v->name, "slowsequence")) {
         slowsequence = ast_true(v->value);
      } else if (!strcasecmp(v->name, "transfer")) {
         transfer = ast_true(v->value);
      } else if (!strcasecmp(v->name, "threewaycalling")) {
         threewaycalling = ast_true(v->value);
      } else if (!strcasecmp(v->name, "wcardep")) {
         /* locate existing endpoint */
         for (e = gw->endpoints; e; e = e->next) {
            if (!strcasecmp(v->value, e->name)) {
               /* endpoint already exists */
               e->delme = 0;
               ep_reload = 1;
               break;
            }
         }

         if (!e) {
            /* Allocate wildcard endpoint */
            e = ast_calloc(1, sizeof(*e));
            ep_reload = 0;
         }

         if (e) {
            if (!ep_reload) {
               memset(e, 0, sizeof(struct mgcp_endpoint));
               ast_mutex_init(&e->lock);
               ast_mutex_init(&e->rqnt_queue_lock);
               ast_mutex_init(&e->cmd_queue_lock);
               e->cap = ast_format_cap_alloc_nolock();
               ast_copy_string(e->name, v->value, sizeof(e->name));
               e->needaudit = 1;
            }
            ast_copy_string(gw->wcardep, v->value, sizeof(gw->wcardep));
            /* XXX Should we really check for uniqueness?? XXX */
            ast_copy_string(e->accountcode, accountcode, sizeof(e->accountcode));
            ast_copy_string(e->context, context, sizeof(e->context));
            ast_copy_string(e->cid_num, cid_num, sizeof(e->cid_num));
            ast_copy_string(e->cid_name, cid_name, sizeof(e->cid_name));
            ast_copy_string(e->language, language, sizeof(e->language));
            ast_copy_string(e->musicclass, musicclass, sizeof(e->musicclass));
            ast_copy_string(e->mailbox, mailbox, sizeof(e->mailbox));
            ast_copy_string(e->parkinglot, parkinglot, sizeof(e->parkinglot));
            if (!ast_strlen_zero(e->mailbox)) {
               char *mbox, *cntx;
               cntx = mbox = ast_strdupa(e->mailbox);
               strsep(&cntx, "@");
               if (ast_strlen_zero(cntx)) {
                  cntx = "default";
               }
               e->mwi_event_sub = ast_event_subscribe(AST_EVENT_MWI, mwi_event_cb, "MGCP MWI subscription", NULL,
                  AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mbox,
                  AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, cntx,
                  AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_EXISTS,
                  AST_EVENT_IE_END);
            }
            snprintf(e->rqnt_ident, sizeof(e->rqnt_ident), "%08lx", ast_random());
            e->msgstate = -1;
            e->amaflags = amaflags;
            ast_format_cap_copy(e->cap, global_capability);
            e->parent = gw;
            e->ncs = ncs;
            e->dtmfmode = dtmfmode;
            if (!ep_reload && e->sub && e->sub->rtp) {
               e->dtmfmode |= MGCP_DTMF_INBAND;
            }
            e->adsi = adsi;
            e->type = TYPE_LINE;
            e->immediate = immediate;
            e->callgroup=cur_callergroup;
            e->pickupgroup=cur_pickupgroup;
            e->callreturn = callreturn;
            e->cancallforward = cancallforward;
            e->singlepath = singlepath;
            e->directmedia = directmedia;
            e->callwaiting = callwaiting;
            e->hascallwaiting = callwaiting;
            e->slowsequence = slowsequence;
            e->transfer = transfer;
            e->threewaycalling = threewaycalling;
            e->onhooktime = time(NULL);
            /* ASSUME we're onhook */
            e->hookstate = MGCP_ONHOOK;
            e->chanvars = copy_vars(chanvars);
            if (!ep_reload) {
               /*snprintf(txident, sizeof(txident), "%08lx", ast_random());*/
               for (i = 0; i < MAX_SUBS; i++) {
                  sub = ast_calloc(1, sizeof(*sub));
                  if (sub) {
                     ast_verb(3, "Allocating subchannel '%d' on %s@%s\n", i, e->name, gw->name);
                     ast_mutex_init(&sub->lock);
                     ast_mutex_init(&sub->cx_queue_lock);
                     sub->parent = e;
                     sub->id = i;
                     snprintf(sub->txident, sizeof(sub->txident), "%08lx", ast_random());
                     /*stnrcpy(sub->txident, txident, sizeof(sub->txident) - 1);*/
                     sub->cxmode = MGCP_CX_INACTIVE;
                     sub->nat = nat;
                     sub->gate = NULL;
                     sub->sdpsent = 0;
                     sub->next = e->sub;
                     e->sub = sub;
                  } else {
                     /* XXX Should find a way to clean up our memory */
                     ast_log(LOG_WARNING, "Out of memory allocating subchannel\n");
                     return NULL;
                  }
               }
               /* Make out subs a circular linked list so we can always sping through the whole bunch */
               /* find the end of the list */
               for (sub = e->sub; sub && sub->next; sub = sub->next);
               /* set the last sub->next to the first sub */
               sub->next = e->sub;

               e->next = gw->endpoints;
               gw->endpoints = e;
            }
         }
      } else if (!strcasecmp(v->name, "trunk") ||
                 !strcasecmp(v->name, "line")) {

         /* locate existing endpoint */
         for (e = gw->endpoints; e; e = e->next) {
            if (!strcasecmp(v->value, e->name)) {
               /* endpoint already exists */
               e->delme = 0;
               ep_reload = 1;
               break;
            }
         }

         if (!e) {
            e = ast_calloc(1, sizeof(*e));
            ep_reload = 0;
         }

         if (e) {
            if (!ep_reload) {
               ast_mutex_init(&e->lock);
               ast_mutex_init(&e->rqnt_queue_lock);
               ast_mutex_init(&e->cmd_queue_lock);
               e->cap = ast_format_cap_alloc_nolock();
               ast_copy_string(e->name, v->value, sizeof(e->name));
               e->needaudit = 1;
            }
            /* XXX Should we really check for uniqueness?? XXX */
            ast_copy_string(e->accountcode, accountcode, sizeof(e->accountcode));
            ast_copy_string(e->context, context, sizeof(e->context));
            ast_copy_string(e->cid_num, cid_num, sizeof(e->cid_num));
            ast_copy_string(e->cid_name, cid_name, sizeof(e->cid_name));
            ast_copy_string(e->language, language, sizeof(e->language));
            ast_copy_string(e->musicclass, musicclass, sizeof(e->musicclass));
            ast_copy_string(e->mailbox, mailbox, sizeof(e->mailbox));
            ast_copy_string(e->parkinglot, parkinglot, sizeof(e->parkinglot));
            if (!ast_strlen_zero(mailbox)) {
               ast_verb(3, "Setting mailbox '%s' on %s@%s\n", mailbox, gw->name, e->name);
            }
            if (!ep_reload) {
               /* XXX potential issue due to reload */
               e->msgstate = -1;
               e->parent = gw;
            }
            e->amaflags = amaflags;
            ast_format_cap_copy(e->cap, global_capability);
            e->dtmfmode = dtmfmode;
            e->ncs = ncs;
            e->pktcgatealloc = pktcgatealloc;
            e->hangupongateremove = hangupongateremove;
            e->adsi = adsi;
            e->type = (!strcasecmp(v->name, "trunk")) ? TYPE_TRUNK : TYPE_LINE;
            e->immediate = immediate;
            e->callgroup=cur_callergroup;
            e->pickupgroup=cur_pickupgroup;
            e->callreturn = callreturn;
            e->cancallforward = cancallforward;
            e->directmedia = directmedia;
            e->singlepath = singlepath;
            e->callwaiting = callwaiting;
            e->hascallwaiting = callwaiting;
            e->slowsequence = slowsequence;
            e->transfer = transfer;
            e->threewaycalling = threewaycalling;

            /* If we already have a valid chanvars, it's not a new endpoint (it's a reload),
               so first, free previous mem
             */
            if (e->chanvars) {
               ast_variables_destroy(e->chanvars);
               e->chanvars = NULL;
            }
            e->chanvars = copy_vars(chanvars);

            if (!ep_reload) {
               e->onhooktime = time(NULL);
               /* ASSUME we're onhook */
               e->hookstate = MGCP_ONHOOK;
               snprintf(e->rqnt_ident, sizeof(e->rqnt_ident), "%08lx", ast_random());
            }

            for (i = 0, sub = NULL; i < MAX_SUBS; i++) {
               if (!ep_reload) {
                  sub = ast_calloc(1, sizeof(*sub));
               } else {
                  if (!sub) {
                     sub = e->sub;
                  } else {
                     sub = sub->next;
                  }
               }

               if (sub) {
                  if (!ep_reload) {
                     ast_verb(3, "Allocating subchannel '%d' on %s@%s\n", i, e->name, gw->name);
                     ast_mutex_init(&sub->lock);
                     ast_mutex_init(&sub->cx_queue_lock);
                     ast_copy_string(sub->magic, MGCP_SUBCHANNEL_MAGIC, sizeof(sub->magic));
                     sub->parent = e;
                     sub->id = i;
                     snprintf(sub->txident, sizeof(sub->txident), "%08lx", ast_random());
                     sub->cxmode = MGCP_CX_INACTIVE;
                     sub->next = e->sub;
                     e->sub = sub;
                  }
                  sub->nat = nat;
               } else {
                  /* XXX Should find a way to clean up our memory */
                  ast_log(LOG_WARNING, "Out of memory allocating subchannel\n");
                  return NULL;
               }
            }
            if (!ep_reload) {
               /* Make out subs a circular linked list so we can always sping through the whole bunch */
               /* find the end of the list */
               for (sub = e->sub; sub && sub->next; sub = sub->next);
               /* set the last sub->next to the first sub */
               sub->next = e->sub;

               e->next = gw->endpoints;
               gw->endpoints = e;
            }
         }
      } else if (!strcasecmp(v->name, "name") || !strcasecmp(v->name, "lines")) {
         /* just eliminate realtime warnings */
      } else {
         ast_log(LOG_WARNING, "Don't know keyword '%s' at line %d\n", v->name, v->lineno);
      }
   }
   if (!ntohl(gw->addr.sin_addr.s_addr) && !gw->dynamic) {
      ast_log(LOG_WARNING, "Gateway '%s' lacks IP address and isn't dynamic\n", gw->name);
      if (!gw_reload) {
         ast_mutex_destroy(&gw->msgs_lock);
         ast_free(gw);
      }

      /* Return NULL */
      gw_reload = 1;
   } else {
      gw->defaddr.sin_family = AF_INET;
      gw->addr.sin_family = AF_INET;
      if (gw->defaddr.sin_addr.s_addr && !ntohs(gw->defaddr.sin_port)) {
         gw->defaddr.sin_port = htons(DEFAULT_MGCP_GW_PORT);
      }
      if (gw->addr.sin_addr.s_addr && !ntohs(gw->addr.sin_port)) {
         gw->addr.sin_port = htons(DEFAULT_MGCP_GW_PORT);
      }
      {
         struct ast_sockaddr tmp1, tmp2;
         struct sockaddr_in tmp3 = {0,};

         tmp3.sin_addr = gw->ourip;
         ast_sockaddr_from_sin(&tmp1, &gw->addr);
         ast_sockaddr_from_sin(&tmp2, &tmp3);
         if (gw->addr.sin_addr.s_addr && ast_ouraddrfor(&tmp1, &tmp2)) {
            memcpy(&gw->ourip, &__ourip, sizeof(gw->ourip));
         } else {
            ast_sockaddr_to_sin(&tmp2, &tmp3);
            gw->ourip = tmp3.sin_addr;
         }
      }
   }

   if (chanvars) {
      ast_variables_destroy(chanvars);
      chanvars = NULL;
   }
   return (gw_reload ? NULL : gw);
}

static enum ast_rtp_glue_result mgcp_get_rtp_peer(struct ast_channel *chan, struct ast_rtp_instance **instance)
{
   struct mgcp_subchannel *sub = NULL;

   if (!(sub = ast_channel_tech_pvt(chan)) || !(sub->rtp))
      return AST_RTP_GLUE_RESULT_FORBID;

   *instance = sub->rtp ? ao2_ref(sub->rtp, +1), sub->rtp : NULL;

   if (sub->parent->directmedia)
      return AST_RTP_GLUE_RESULT_REMOTE;
   else
      return AST_RTP_GLUE_RESULT_LOCAL;
}

static int mgcp_set_rtp_peer(struct ast_channel *chan, struct ast_rtp_instance *rtp, struct ast_rtp_instance *vrtp, struct ast_rtp_instance *trtp, const struct ast_format_cap *cap, int nat_active)
{
   /* XXX Is there such thing as video support with MGCP? XXX */
   struct mgcp_subchannel *sub;
   sub = ast_channel_tech_pvt(chan);
   if (sub && !sub->alreadygone) {
      transmit_modify_with_sdp(sub, rtp, cap);
      return 0;
   }
   return -1;
}

static void mgcp_get_codec(struct ast_channel *chan, struct ast_format_cap *result)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(chan);
   struct mgcp_endpoint *p = sub->parent;
   ast_format_cap_copy(result, p->cap);
}

static struct ast_rtp_glue mgcp_rtp_glue = {
   .type = "MGCP",
   .get_rtp_info = mgcp_get_rtp_peer,
   .update_peer = mgcp_set_rtp_peer,
   .get_codec = mgcp_get_codec,
};


static int acf_channel_read(struct ast_channel *chan, const char *funcname, char *args, char *buf, size_t buflen)
{
   struct mgcp_subchannel *sub = ast_channel_tech_pvt(chan);
   int res = 0;

   /* Sanity check */
   if (!chan || ast_channel_tech(chan) != &mgcp_tech) {
      ast_log(LOG_ERROR, "This function requires a valid MGCP channel\n");
      return -1;
   }

   if (!strcasecmp(args, "ncs")) {
      snprintf(buf, buflen, "%s", sub->parent->ncs ?  "yes":"no");
   } else {
      res = -1;
   }
   return res;
}


static void destroy_endpoint(struct mgcp_endpoint *e)
{
   struct mgcp_subchannel *sub = e->sub->next, *s;
   int i;

   for (i = 0; i < MAX_SUBS; i++) {
      ast_mutex_lock(&sub->lock);
      if (!ast_strlen_zero(sub->cxident)) {
         transmit_connection_del(sub);
      }
      if (sub->rtp) {
         ast_rtp_instance_destroy(sub->rtp);
         sub->rtp = NULL;
      }
      memset(sub->magic, 0, sizeof(sub->magic));
      mgcp_queue_hangup(sub);
      dump_cmd_queues(NULL, sub);
      if(sub->gate) {
         sub->gate->tech_pvt = NULL;
         sub->gate->got_dq_gi = NULL;
         sub->gate->gate_remove = NULL;
         sub->gate->gate_open = NULL;
      }
      ast_mutex_unlock(&sub->lock);
      sub = sub->next;
   }

   if (e->dsp) {
      ast_dsp_free(e->dsp);
   }

   dump_queue(e->parent, e);
   dump_cmd_queues(e, NULL);

   sub = e->sub;
   for (i = 0; (i < MAX_SUBS) && sub; i++) {
      s = sub;
      sub = sub->next;
      ast_mutex_destroy(&s->lock);
      ast_mutex_destroy(&s->cx_queue_lock);
      ast_free(s);
   }

   if (e->mwi_event_sub)
      ast_event_unsubscribe(e->mwi_event_sub);

   if (e->chanvars) {
      ast_variables_destroy(e->chanvars);
      e->chanvars = NULL;
   }

   ast_mutex_destroy(&e->lock);
   ast_mutex_destroy(&e->rqnt_queue_lock);
   ast_mutex_destroy(&e->cmd_queue_lock);
   e->cap = ast_format_cap_destroy(e->cap);
   ast_free(e);
}

static void destroy_gateway(struct mgcp_gateway *g)
{
   if (g->ha)
      ast_free_ha(g->ha);

   dump_queue(g, NULL);

   ast_free(g);
}

static void prune_gateways(void)
{
   struct mgcp_gateway *g, *z, *r;
   struct mgcp_endpoint *e, *p, *t;

   ast_mutex_lock(&gatelock);

   /* prune gateways */
   for (z = NULL, g = gateways; g;) {
      /* prune endpoints */
      for (p = NULL, e = g->endpoints; e; ) {
         if (!g->realtime && (e->delme || g->delme)) {
            t = e;
            e = e->next;
            if (!p)
               g->endpoints = e;
            else
               p->next = e;
            destroy_endpoint(t);
         } else {
            p = e;
            e = e->next;
         }
      }

      if (g->delme) {
         r = g;
         g = g->next;
         if (!z)
            gateways = g;
         else
            z->next = g;

         destroy_gateway(r);
      } else {
         z = g;
         g = g->next;
      }
   }

   ast_mutex_unlock(&gatelock);
}

static struct ast_variable *add_var(const char *buf, struct ast_variable *list)
{
   struct ast_variable *tmpvar = NULL;
   char *varname = ast_strdupa(buf), *varval = NULL;

   if ((varval = strchr(varname, '='))) {
      *varval++ = '\0';
      if ((tmpvar = ast_variable_new(varname, varval, ""))) {
         tmpvar->next = list;
         list = tmpvar;
      }
   }
   return list;
}

/*! \brief
 * duplicate a list of channel variables, \return the copy.
 */
static struct ast_variable *copy_vars(struct ast_variable *src)
{
   struct ast_variable *res = NULL, *tmp, *v = NULL;

   for (v = src ; v ; v = v->next) {
      if ((tmp = ast_variable_new(v->name, v->value, v->file))) {
         tmp->next = res;
         res = tmp;
      }
   }
   return res;
}


static int reload_config(int reload)
{
   struct ast_config *cfg;
   struct ast_variable *v;
   struct mgcp_gateway *g;
   struct mgcp_endpoint *e;
   char *cat;
   struct ast_hostent ahp;
   struct hostent *hp;
   struct ast_format format;
   struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
   
   if (gethostname(ourhost, sizeof(ourhost)-1)) {
      ast_log(LOG_WARNING, "Unable to get hostname, MGCP disabled\n");
      return 0;
   }
   cfg = ast_config_load(config, config_flags);

   /* We *must* have a config file otherwise stop immediately */
   if (!cfg) {
      ast_log(LOG_NOTICE, "Unable to load config %s, MGCP disabled\n", config);
      return 0;
   } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
      return 0;
   } else if (cfg == CONFIG_STATUS_FILEINVALID) {
      ast_log(LOG_ERROR, "Config file %s is in an invalid format.  Aborting.\n", config);
      return 0;
   }

   memset(&bindaddr, 0, sizeof(bindaddr));
   dtmfmode = 0;

   /* Copy the default jb config over global_jbconf */
   memcpy(&global_jbconf, &default_jbconf, sizeof(struct ast_jb_conf));

   for (v = ast_variable_browse(cfg, "general"); v; v = v->next) {
      /* handle jb conf */
      if (!ast_jb_read_conf(&global_jbconf, v->name, v->value)) {
         continue;
      }

      /* Create the interface list */
      if (!strcasecmp(v->name, "bindaddr")) {
         if (!(hp = ast_gethostbyname(v->value, &ahp))) {
            ast_log(LOG_WARNING, "Invalid address: %s\n", v->value);
         } else {
            memcpy(&bindaddr.sin_addr, hp->h_addr, sizeof(bindaddr.sin_addr));
         }
      } else if (!strcasecmp(v->name, "allow")) {
         ast_getformatbyname(v->value, &format);
         if (!format.id) {
            ast_log(LOG_WARNING, "Cannot allow unknown format '%s'\n", v->value);
         } else {
            ast_format_cap_add(global_capability, &format);
         }
      } else if (!strcasecmp(v->name, "disallow")) {
         ast_getformatbyname(v->value, &format);
         if (!format.id) {
            ast_log(LOG_WARNING, "Cannot allow unknown format '%s'\n", v->value);
         } else {
            ast_format_cap_remove(global_capability, &format);
         }
      } else if (!strcasecmp(v->name, "tos")) {
         if (ast_str2tos(v->value, &qos.tos)) {
             ast_log(LOG_WARNING, "Invalid tos value at line %d, refer to QoS documentation\n", v->lineno);
         }
      } else if (!strcasecmp(v->name, "tos_audio")) {
         if (ast_str2tos(v->value, &qos.tos_audio))
             ast_log(LOG_WARNING, "Invalid tos_audio value at line %d, refer to QoS documentation\n", v->lineno);
      } else if (!strcasecmp(v->name, "cos")) {
         if (ast_str2cos(v->value, &qos.cos))
             ast_log(LOG_WARNING, "Invalid cos value at line %d, refer to QoS documentation\n", v->lineno);
      } else if (!strcasecmp(v->name, "cos_audio")) {
         if (ast_str2cos(v->value, &qos.cos_audio))
             ast_log(LOG_WARNING, "Invalid cos_audio value at line %d, refer to QoS documentation\n", v->lineno);
      } else if (!strcasecmp(v->name, "port")) {
         if (sscanf(v->value, "%5d", &ourport) == 1) {
            bindaddr.sin_port = htons(ourport);
         } else {
            ast_log(LOG_WARNING, "Invalid port number '%s' at line %d of %s\n", v->value, v->lineno, config);
         }
      } else if (!strcasecmp(v->name, "firstdigittimeout")) {
         firstdigittimeout = atoi(v->value);
      } else if (!strcasecmp(v->name, "gendigittimeout")) {
         gendigittimeout = atoi(v->value);
      } else if (!strcasecmp(v->name, "matchdigittimeout")) {
         matchdigittimeout = atoi(v->value);
      }
   }

   /* mark existing entries for deletion */
   ast_mutex_lock(&gatelock);
   for (g = gateways; g; g = g->next) {
      g->delme = 1;
      for (e = g->endpoints; e; e = e->next) {
         e->delme = 1;
      }
   }
   ast_mutex_unlock(&gatelock);

   for (cat = ast_category_browse(cfg, NULL); cat; cat = ast_category_browse(cfg, cat)) {
      if (strcasecmp(cat, "general")) {
         ast_mutex_lock(&gatelock);
         if ((g = build_gateway(cat, ast_variable_browse(cfg, cat)))) {
            ast_verb(3, "Added gateway '%s'\n", g->name);
            g->next = gateways;
            gateways = g;
         }
         ast_mutex_unlock(&gatelock);

         /* FS: process queue and IO */
         if (monitor_thread == pthread_self()) {
            if (sched) ast_sched_runq(sched);
            if (io) ast_io_wait(io, 10);
         }
      }
   }

   /* prune deleted entries etc. */
   prune_gateways();

   if (ntohl(bindaddr.sin_addr.s_addr)) {
      memcpy(&__ourip, &bindaddr.sin_addr, sizeof(__ourip));
   } else {
      hp = ast_gethostbyname(ourhost, &ahp);
      if (!hp) {
         ast_log(LOG_WARNING, "Unable to get our IP address, MGCP disabled\n");
         ast_config_destroy(cfg);
         return 0;
      }
      memcpy(&__ourip, hp->h_addr, sizeof(__ourip));
   }
   if (!ntohs(bindaddr.sin_port))
      bindaddr.sin_port = htons(DEFAULT_MGCP_CA_PORT);
   bindaddr.sin_family = AF_INET;
   ast_mutex_lock(&netlock);
   if (mgcpsock > -1)
      close(mgcpsock);

   if (mgcpsock_read_id != NULL)
      ast_io_remove(io, mgcpsock_read_id);
   mgcpsock_read_id = NULL;

   mgcpsock = socket(AF_INET, SOCK_DGRAM, 0);
   if (mgcpsock < 0) {
      ast_log(LOG_WARNING, "Unable to create MGCP socket: %s\n", strerror(errno));
   } else {
      if (bind(mgcpsock, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) < 0) {
         ast_log(LOG_WARNING, "Failed to bind to %s:%d: %s\n",
            ast_inet_ntoa(bindaddr.sin_addr), ntohs(bindaddr.sin_port),
               strerror(errno));
         close(mgcpsock);
         mgcpsock = -1;
      } else {
         ast_verb(2, "MGCP Listening on %s:%d\n",
               ast_inet_ntoa(bindaddr.sin_addr), ntohs(bindaddr.sin_port));
         ast_set_qos(mgcpsock, qos.tos, qos.cos, "MGCP");
      }
   }
   ast_mutex_unlock(&netlock);
   ast_config_destroy(cfg);

   /* send audit only to the new endpoints */
   for (g = gateways; g; g = g->next) {
      for (e = g->endpoints; e && e->needaudit; e = e->next) {
         e->needaudit = 0;
         transmit_audit_endpoint(e);
         ast_verb(3, "MGCP Auditing endpoint %s@%s for hookstate\n", e->name, g->name);
      }
   }

   return 0;
}

/*! \brief  load_module: PBX load module - initialization ---*/
static int load_module(void)
{
   struct ast_format tmpfmt;

   if (!(global_capability = ast_format_cap_alloc())) {
      return AST_MODULE_LOAD_FAILURE;
   }
   if (!(mgcp_tech.capabilities = ast_format_cap_alloc())) {
      return AST_MODULE_LOAD_FAILURE;
   }
   ast_format_cap_add(global_capability, ast_format_set(&tmpfmt, AST_FORMAT_ULAW, 0));
   ast_format_cap_add(mgcp_tech.capabilities, ast_format_set(&tmpfmt, AST_FORMAT_ULAW, 0));
   ast_format_cap_add(mgcp_tech.capabilities, ast_format_set(&tmpfmt, AST_FORMAT_ALAW, 0));
   if (!(sched = ast_sched_context_create())) {
      ast_log(LOG_WARNING, "Unable to create schedule context\n");
      return AST_MODULE_LOAD_FAILURE;
   }

   if (!(io = io_context_create())) {
      ast_log(LOG_WARNING, "Unable to create I/O context\n");
      ast_sched_context_destroy(sched);
      return AST_MODULE_LOAD_FAILURE;
   }

   if (reload_config(0))
      return AST_MODULE_LOAD_DECLINE;

   /* Make sure we can register our mgcp channel type */
   if (ast_channel_register(&mgcp_tech)) {
      ast_log(LOG_ERROR, "Unable to register channel class 'MGCP'\n");
      io_context_destroy(io);
      ast_sched_context_destroy(sched);
      return AST_MODULE_LOAD_FAILURE;
   }

   ast_rtp_glue_register(&mgcp_rtp_glue);
   ast_cli_register_multiple(cli_mgcp, sizeof(cli_mgcp) / sizeof(struct ast_cli_entry));

   /* And start the monitor for the first time */
   restart_monitor();

   return AST_MODULE_LOAD_SUCCESS;
}

static char *mgcp_reload(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   static int deprecated = 0;

   if (e) {
      switch (cmd) {
      case CLI_INIT:
         e->command = "mgcp reload";
         e->usage =
            "Usage: mgcp reload\n"
            "       'mgcp reload' is deprecated.  Please use 'reload chan_mgcp.so' instead.\n";
         return NULL;
      case CLI_GENERATE:
         return NULL;
      }
   }

   if (!deprecated && a && a->argc > 0) {
      ast_log(LOG_WARNING, "'mgcp reload' is deprecated.  Please use 'reload chan_mgcp.so' instead.\n");
      deprecated = 1;
   }

   ast_mutex_lock(&mgcp_reload_lock);
   if (mgcp_reloading) {
      ast_verbose("Previous mgcp reload not yet done\n");
   } else {
      mgcp_reloading = 1;
   }
   ast_mutex_unlock(&mgcp_reload_lock);
   restart_monitor();
   return CLI_SUCCESS;
}

static int reload(void)
{
   mgcp_reload(NULL, 0, NULL);
   return 0;
}

static int unload_module(void)
{
   struct mgcp_endpoint *e;
   struct mgcp_gateway *g;

   /* Check to see if we're reloading */
   if (ast_mutex_trylock(&mgcp_reload_lock)) {
      ast_log(LOG_WARNING, "MGCP is currently reloading.  Unable to remove module.\n");
      return -1;
   } else {
      mgcp_reloading = 1;
      ast_mutex_unlock(&mgcp_reload_lock);
   }

   /* First, take us out of the channel loop */
   ast_channel_unregister(&mgcp_tech);

   /* Shut down the monitoring thread */
   if (!ast_mutex_lock(&monlock)) {
      if (monitor_thread && (monitor_thread != AST_PTHREADT_STOP)) {
         pthread_cancel(monitor_thread);
         pthread_kill(monitor_thread, SIGURG);
         pthread_join(monitor_thread, NULL);
      }
      monitor_thread = AST_PTHREADT_STOP;
      ast_mutex_unlock(&monlock);
   } else {
      ast_log(LOG_WARNING, "Unable to lock the monitor\n");
      /* We always want to leave this in a consistent state */
      ast_channel_register(&mgcp_tech);
      mgcp_reloading = 0;
      mgcp_reload(NULL, 0, NULL);
      return -1;
   }

   if (!ast_mutex_lock(&gatelock)) {
      for (g = gateways; g; g = g->next) {
         g->delme = 1;
         for (e = g->endpoints; e; e = e->next) {
            e->delme = 1;
         }
      }

      prune_gateways();
      ast_mutex_unlock(&gatelock);
   } else {
      ast_log(LOG_WARNING, "Unable to lock the gateways list.\n");
      /* We always want to leave this in a consistent state */
      ast_channel_register(&mgcp_tech);
      /* Allow the monitor to restart */
      monitor_thread = AST_PTHREADT_NULL;
      mgcp_reloading = 0;
      mgcp_reload(NULL, 0, NULL);
      return -1;
   }

   close(mgcpsock);
   ast_rtp_glue_unregister(&mgcp_rtp_glue);
   ast_cli_unregister_multiple(cli_mgcp, sizeof(cli_mgcp) / sizeof(struct ast_cli_entry));
   ast_sched_context_destroy(sched);

   global_capability = ast_format_cap_destroy(global_capability);
   mgcp_tech.capabilities = ast_format_cap_destroy(mgcp_tech.capabilities);

   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Media Gateway Control Protocol (MGCP)",
      .load = load_module,
      .unload = unload_module,
      .reload = reload,
      .load_pri = AST_MODPRI_CHANNEL_DRIVER,
      .nonoptreq = "res_pktccops",
          );