[svn-commits] rizzo: branch rizzo/astobj2 r76219 - /team/rizzo/astobj2/channels/chan_sip.c

[SVN commits to the Digium repositories]

Author: rizzo
Date: Fri Jul 20 18:38:38 2007
New Revision: 76219

URL: http://svn.digium.com/view/asterisk?view=rev&rev=76219
Log:
improve documentation related to externip/stun handling

Modified:
    team/rizzo/astobj2/channels/chan_sip.c

Modified: team/rizzo/astobj2/channels/chan_sip.c
URL: http://svn.digium.com/view/asterisk/team/rizzo/astobj2/channels/chan_sip.c?view=diff&rev=76219&r1=76218&r2=76219
==============================================================================
--- team/rizzo/astobj2/channels/chan_sip.c (original)
+++ team/rizzo/astobj2/channels/chan_sip.c Fri Jul 20 18:38:38 2007
@@ -1394,8 +1394,8 @@
  * bound to fail anyways, so we just live with this event and let
  * the protocol handle this above us.
  */
-
 static volatile int sipsock  = -1;			/*!< Main socket for SIP network communication */
+
 static struct sockaddr_in bindaddr;		/*!< The address we bind to */
 
 /*! \brief our (internal) default address/port to put in SIP/SDP messages
@@ -1422,6 +1422,7 @@
  *   to the specified server, and store the result in externip.
  */
 static struct sockaddr_in externip;		/*!< External IP address if we are behind NAT */
+
 static char externhost[MAXHOSTNAMELEN];		/*!< External host name */
 static time_t externexpire;			/*!< Expiration counter for re-resolving external host name in dynamic DNS */
 static int externrefresh = 10;
@@ -1433,7 +1434,7 @@
  * AST_SENSE_DENY for 'local' addresses, and AST_SENSE_ALLOW for 'non local'
  * (i.e. presumably public) addresses.
  */
-static struct ast_ha *localaddr;
+static struct ast_ha *localaddr;		/*!< List of local networks, on the same side of NAT as this Asterisk */
 
 static struct sockaddr_in debugaddr;
 
@@ -2210,37 +2211,33 @@
 static void ast_sip_ouraddrfor(struct in_addr *them, struct sockaddr_in *us)
 {
 	struct sockaddr_in theirs;
-	/* Set want_remap to non-zero if we want to remap 'us'.
-	 * Conditions are that we have a localaddr list,
-	 * either stunaddr or externip is set,
-	 * the remote address does not match any of the 'localaddr' entries,
-	 * and (cheched later) some other condition on 'us'.
+	/* Set want_remap to non-zero if we want to remap 'us' to an externally
+	 * reachable IP address and port. This is done if:
+	 * 1. we have a localaddr list (containing 'internal' addresses marked
+	 *    as 'deny', so ast_apply_ha() will return AST_SENSE_DENY on them,
+	 *    and AST_SENSE_ALLOW on 'external' ones);
+	 * 2. either stunaddr or externip is set, so we know what to use as the
+	 *    externally visible address;
+	 * 3. the remote address, 'them', is external;
+	 * 4. the address returned by ast_ouraddrfor() is 'internal' (AST_SENSE_DENY
+	 *    when passed to ast_apply_ha() so it does need to be remapped.
+	 *    This fourth condition is checked later.
 	 */
 	int want_remap = localaddr &&
 		(externip.sin_addr.s_addr || stunaddr.sin_addr.s_addr) &&
 		ast_apply_ha(localaddr, &theirs) == AST_SENSE_ALLOW ;
 
-	/* localaddr contains 'internal' addresses marked as 'deny',
-	 * so 'external' addresses will return AST_SENSE_ALLOW.
-	 * In the following, we check if we need to remap the system-supplied
-	 * address to an externally visible one, and use some appropriate
-	 * mechanism to do that.
-	 */
-
-	*us = internip;		/* start from something reasonable */
-	/* Start from the address that the system would use */
+	*us = internip;		/* starting guess for the internal address */
+	/* now ask the system what would it use to talk to 'them' */
 	ast_ouraddrfor(them, &us->sin_addr);
 	theirs.sin_addr = *them;
 
-	if (want_remap
-		&& (!global_matchexterniplocally || !ast_apply_ha(localaddr, us)) /* we want to remap */
-			) { 
+	if (want_remap &&
+		(!global_matchexterniplocally || !ast_apply_ha(localaddr, us)) ) { 
 		/* if we used externhost or stun, see if it is time to refresh the info */
 		if (externexpire && time(NULL) >= externexpire) {
 			if (stunaddr.sin_addr.s_addr) {
 				ast_stun_request(sipsock, &stunaddr, NULL, &externip);
-				ast_log(LOG_WARNING, "stun(2) sees us at %s:%d\n",
-						ast_inet_ntoa(externip.sin_addr) , ntohs(externip.sin_port));
 			} else {
 				if (ast_parse_arg(externhost, PARSE_INADDR, &externip))
 					ast_log(LOG_NOTICE, "Warning: Re-lookup of '%s' failed!\n", externhost);
@@ -2254,9 +2251,7 @@
 		ast_debug(1, "Target address %s is not local, substituting externip\n", 
 				ast_inet_ntoa(*(struct in_addr *)&them->s_addr));
 	} else if (bindaddr.sin_addr.s_addr) {
-		/* remapping is not allowed, but we bind to
-		 * a specific address, so use it.
-		 */
+		/* no remapping, but we bind to a specific address, so use it. */
 		*us = bindaddr;
 	}
 }
@@ -4925,8 +4920,9 @@
 	if (intended_method != SIP_OPTIONS)	/* Peerpoke has it's own system */
 		p->timer_t1 = SIP_TIMER_T1;	/* Default SIP retransmission timer T1 (RFC 3261) */
 
-	p->ourip = internip;
-	if (sin) {
+	if (!sin)
+		p->ourip = internip;
+	else {
 		p->sa = *sin;
 		ast_sip_ouraddrfor(&p->sa.sin_addr, &p->ourip);
 	}
@@ -6612,8 +6608,9 @@
 	/* Initialize the bare minimum */
 	p->method = intended_method;
 
-	p->ourip = internip;
-	if (sin) {
+	if (!sin)
+		p->ourip = internip;
+	else {
 		p->sa = *sin;
 		ast_sip_ouraddrfor(&p->sa.sin_addr, &p->ourip);
 	}