[sr-dev] force send socket/tcp send problem

[Juha Heinanen]

while doing some tests with close to latest master version, i noticed
that forcing send socket does not match wiki $fs description (or i have
misunderstood it):

  $fs - reference to the forced socket for message sending (if any) in the
  form proto:ip:port 

  It is R/W variable (you can assign values to it directly in
  configuration file). Transport proto can be omitted when assigning
  value, in which case it is taken from destination URI of the message.

in config i execute:

  xlog("L_INFO", "**** du = <$du>\n");
  $fs = "192.98.101.20:5060";
  xlog("L_INFO", "**** fs = <$fs>\n");

and i get to syslog:

Sep 14 20:49:18 lohi /usr/bin/sip-proxy[6610]: INFO: **** du = <sip:192.98.102.10;transport=tcp>
Sep 14 20:49:18 lohi /usr/bin/sip-proxy[6610]: INFO: **** fs = <udp:192.98.101.20:5060>
Sep 14 20:49:18 lohi /usr/bin/sip-proxy[6610]: ERROR: tm [../../forward.h:223]: msg_send(): msg_send: ERROR: tcp_send failed

it shows that even when transport of $du is tcp, transport proto of fs
is udp.

another weird thing is that when i add proto to the assignment:

  $fs = "tcp:192.98.101.20:5060";

i still get the same tcp_send failed error.

my proxy is definitely listening on tcp:192.98.101.20:5060 and 'telnet
192.98.102.10 5060' shows that tcp connection succeeds.

the only explanation that comes to mind is if i have called
set_forward_no_connect(), but i have not found such a call.  is there a
function call to revert set_forward_no_connect()? 

is it somehow possible to find out why tcp_send fails?

-- juha