looks like branch flags get corrupted - sr-dev

30 Oct 2009


      i started to wonder why my proxy is calling fix_natted_contact() in
onreply route even when called ua is not behind nat.  the function is
called under condition
if (isbflagset("TO_NATED") &&
    		t_check_status("18[0-9]|2[0-9][0-9]|3[0-9][0-9]")) {
        xlog("L_INFO", "Fixing nated contact in onreply_route\n");
    	fix_nated_contact();
    };
i then added xlog telling if "TO_NATED" flags is set when request is
sent out:
if (isbflagset("TO_NATED")) {
    	xlog("L_INFO", "Flag to_nated is set before t_relay\n");
    } else {
    	xlog("L_INFO", "Flag to_nated is NOT set before t_relay\n");
    }
it turns out that sometimes TO_NATED flag is set and sometimes not even
when the calls are exactly identical.
here is my example call: "jh" (behind nat) calls "foo", "foo" has forwarding
on in the proxy to "test", which causes the request to be sent back to sr at
127.0.0.1:5070 (and then to "test", but the error has happened 
already and that is not shown).
first example call where TO_NATED flag is set although it should not
have been:
Oct 30 20:45:29 localhost /usr/sbin/sip-proxy[31447]: INFO: INVITE sip:foo@tutpro.com is authorized 
Oct 30 20:45:29 localhost /usr/sbin/sip-proxy[31447]: INFO: Unconditional forwarding to sip:test@tutpro.com 
Oct 30 20:45:29 localhost /usr/sbin/sip-proxy[31447]: INFO: Fixing nated contact in handle_caller_nat
Oct 30 20:45:29 localhost /usr/sbin/sip-proxy[31447]: INFO: Routing initial INVITE sip:test@tutpro.com to sip:127.0.0.1:5070 
Oct 30 20:45:29 localhost /usr/sbin/sip-proxy[31447]: INFO: Flag to_nated is set before t_relay 
...
second example call that works as it should:
Oct 30 20:47:03 localhost /usr/sbin/sip-proxy[31441]: INFO: INVITE sip:foo@tutpro.com is authorized 
Oct 30 20:47:03 localhost /usr/sbin/sip-proxy[31441]: INFO: Unconditional forwarding to sip:test@tutpro.com 
Oct 30 20:47:03 localhost /usr/sbin/sip-proxy[31441]: INFO: Fixing nated contact in handle_caller_nat 
Oct 30 20:47:03 localhost /usr/sbin/sip-proxy[31441]: INFO: Routing initial INVITE sip:test@tutpro.com to sip:127.0.0.1:5070 
Oct 30 20:47:03 localhost /usr/sbin/sip-proxy[31441]: INFO: Flag to_nated is NOT set before t_relay 
...
the only conclusion that i can draw is that branch flags sometimes
get somehow corrupted.
let me know if you need more info or have ideas on how to find the cause
of the problem.  i do also have pcap traces.
-- juha