[asterisk-bugs] [JIRA] (ASTERISK-29276) Asterisk STUN implementation causes delay and doed not work in all network topologies.

[Chris (JIRA)]

Chris created ASTERISK-29276:
--------------------------------

             Summary: Asterisk STUN implementation causes delay and doed not work in all network topologies.
                 Key: ASTERISK-29276
                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-29276
             Project: Asterisk
          Issue Type: Improvement
      Security Level: None
          Components: Resources/res_rtp_asterisk
    Affects Versions: 16.16.0
            Reporter: Chris
            Severity: Major


Despite of the documentation here https://wiki.asterisk.org/wiki/display/~jcolp/ICE,+STUN,+and+TURN+Support Asterisk does *not* implement this RFC rfc5389. Id rather implements RFC https://tools.ietf.org/html/rfc3489 which is known for it's design flaws.

{quote}
However, experience since the publication
   of RFC 3489 has found that classic STUN simply does not work
   sufficiently well to be a deployable solution.  The address and port
   learned through classic STUN are sometimes usable for communications
   with a peer, and sometimes not.  Classic STUN provided no way to
   discover whether it would, in fact, work or not, and it provided no
   remedy in cases where it did not.  Furthermore, classic STUN's
   algorithm for classification of NAT types was found to be faulty, as
   many NATs did not fit cleanly into the types defined there.

{quote}

The current rfc3489 implementation in stun.c also has serious flaws. E.g. it always waits for 3 seconds before doing a retry. 
This means, if the UDP packet is dropped, you immediately have a delay of 3 seconds before the call starts.
{quote}
	/* Wait for response. */
		{
			struct pollfd pfds = { .fd = s, .events = POLLIN };
			int ms;

			//** Reduce to < 200MS
			ms = ast_remaining_ms(start, 3000);
			if (ms <= 0) {
				/* No response, timeout */
				res = 1;
				continue;
			}
			res = ast_poll(&pfds, 1, ms);
			if (res < 0) {
				/* Error */
				continue;
			}
			if (!res) {
				/* No response, timeout */
				res = 1;
				continue;
			}
		}
{quote}

What should be improved :

- Implement RFC rfc5389 or use 3rd party STUN library (pjsip ?)
- Improve wait-loop in stun.c 
- Update the docs reflecting correct RFC




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