[asterisk-dev] [Code Review] Explicit context set in SIP peer overridden by default domain context

[Philip A. Prindeville]

Summary
--------

Having inbound SIP 'guest' calls associated to a default context is
handy, especially when multi-tenancy or hosting multiple domains is
being done.

However, the code as written will clobber an explicitly configured
context associated with a peer if a domain-list is configured.

This is counter-intuitive, since (a) explicit configuration should
always trump default or implicit config, and (b) puts all internal
domain-bound SIP handsets in the same context as guest callers, making
it hard to apply a restricted dialplan to guest callers.

The Fix
-------

Only override the context if (1) it hasn't been explicitly set and (2)
we're not associated with a specific peer.


Testing
--------

Running patched 1.6.2.6 on our production network.  Seems to work fine.


Diffs
-----

--- asterisk-1.6.2.6/channels/chan_sip.c.orig	2010-03-02 17:19:57.000000000 -0700
+++ asterisk-1.6.2.6/channels/chan_sip.c	2010-03-16 13:08:41.000000000 -0600
@@ -13353,8 +13353,10 @@ static int get_destination(struct sip_pv
 				return -2;
 			}
 		}
-		/* If we have a context defined, overwrite the original context */
-		if (!ast_strlen_zero(domain_context))
+		/* If we don't have a context defined (i.e. we're a guest call),
+		 * overwrite the original context */
+		if (!p->owner && ast_strlen_zero(p->context) &&
+		    !ast_strlen_zero(domain_context))
 			ast_string_field_set(p, context, domain_context);
 	}