[Asterisk-code-review] chan sip: Resolve externhost not to IPv6; instead go for IPv4. (asterisk[13])

[Alexander Traud]

Alexander Traud has uploaded a new change for review.

  https://gerrit.asterisk.org/3968

Change subject: chan_sip: Resolve externhost not to IPv6; instead go for IPv4.
......................................................................

chan_sip: Resolve externhost not to IPv6; instead go for IPv4.

For the channel driver chan_sip, you specify externhost=example.com in sip.conf
when your Asterisk is behind a NAT and your IP address is assigned dynamically.
Or stated differently: You do not have a static IP address to use "externaddr"
directly. This NAT support is quite handy but just about IPv4. Previously,
Asterisk resolved "externhost" to any IP version. When the first DNS answer
resolved to an IPv6, Asterisk sent an IPv6 in SIP/SDP for origin (o=) and
connection (c=). This happened in outgoing SIP-REGISTER and while answering
SIP-INVITE. If the remote peer is IPv4-only, it might not handle o=/c= with an
IPv6. This change makes sure, no IPv6 is resolved anymore for "externhost".

ASTERISK-18232 #close
Reported by: Jacek Kowalski
Tested by: Alexander Traud
patches:
 changes.patch submitted by Alessandro Crespi

Change-Id: If68eedbeff65bd1c1d8a9ed921c02ba464b32dac
---
M channels/chan_sip.c
1 file changed, 2 insertions(+), 2 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/68/3968/1

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 51a0869..5ef197b 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -3838,7 +3838,7 @@
 	    (!sip_cfg.matchexternaddrlocally || !ast_apply_ha(localaddr, us)) ) {
 		/* if we used externhost, see if it is time to refresh the info */
 		if (externexpire && time(NULL) >= externexpire) {
-			if (ast_sockaddr_resolve_first(&externaddr, externhost, 0)) {
+			if (ast_sockaddr_resolve_first_af(&externaddr, externhost, 0, AST_AF_INET)) {
 				ast_log(LOG_NOTICE, "Warning: Re-lookup of '%s' failed!\n", externhost);
 			}
 			externexpire = time(NULL) + externrefresh;
@@ -32455,7 +32455,7 @@
 			externexpire = 0;
 		} else if (!strcasecmp(v->name, "externhost")) {
 			ast_copy_string(externhost, v->value, sizeof(externhost));
-			if (ast_sockaddr_resolve_first(&externaddr, externhost, 0)) {
+			if (ast_sockaddr_resolve_first_af(&externaddr, externhost, 0, AST_AF_INET)) {
 				ast_log(LOG_WARNING, "Invalid address for externhost keyword: %s\n", externhost);
 			}
 			externexpire = time(NULL);

-- 
To view, visit https://gerrit.asterisk.org/3968
To unsubscribe, visit https://gerrit.asterisk.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: If68eedbeff65bd1c1d8a9ed921c02ba464b32dac
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Alexander Traud <pabstraud at compuserve.com>