srv.h File Reference

Support for DNS SRV records, used in to locate SIP services. More...

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Functions
int	ast_get_srv (struct ast_channel *chan, char *host, int hostlen, int *port, const char *service)

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Detailed Description

Support for DNS SRV records, used in to locate SIP services.

Note:

Note: This SRV record support will respect the priority and weight elements of the records that are returned, but there are no provisions for retrying or failover between records.

Definition in file srv.h.

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Function Documentation

int ast_get_srv	(	struct ast_channel *	chan,
		char *	host,
		int	hostlen,
		int *	port,
		const char *	service
	)

Lookup entry in SRV records Returns 1 if found, 0 if not found, -1 on hangup Only do SRV record lookup if you get a domain without a port. If you get a port #, it's a DNS host name.

Parameters:

chan	Ast channel
host	host name (return value)
hostlen	Length of string "host"
port	Port number (return value)
service	Service tag for SRV lookup (like "_sip._udp" or "_stun._udp"

Definition at line 200 of file srv.c.

References ast_autoservice_start(), ast_autoservice_stop(), ast_copy_string(), ast_free, AST_LIST_HEAD_NOLOCK_INIT_VALUE, AST_LIST_REMOVE_HEAD, ast_search_dns(), ast_verb, srv_context::entries, srv_context::have_weights, srv_entry::host, srv_entry::port, process_weights(), and srv_callback().

Referenced by ast_get_ip_or_srv(), and create_addr().

{
   struct srv_context context = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE };
   struct srv_entry *current;
   int ret;

   if (chan && ast_autoservice_start(chan) < 0)
      return -1;

   ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback);

   if (context.have_weights)
      process_weights(&context);

   if (chan)
      ret |= ast_autoservice_stop(chan);

   /* TODO: there could be a "." entry in the returned list of
      answers... if so, this requires special handling */

   /* the list of entries will be sorted in the proper selection order
      already, so we just need the first one (if any) */

   if ((ret > 0) && (current = AST_LIST_REMOVE_HEAD(&context.entries, list))) {
      ast_copy_string(host, current->host, hostlen);
      *port = current->port;
      ast_free(current);
      ast_verb(4, "ast_get_srv: SRV lookup for '%s' mapped to host %s, port %d\n",
                service, host, *port);
   } else {
      host[0] = '\0';
      *port = -1;
   }

   while ((current = AST_LIST_REMOVE_HEAD(&context.entries, list)))
      ast_free(current);

   return ret;
}