Append Retry-After header on 500 error response to Re-INVITE according to RFC3261...

ABE-2301

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@288852 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index f3d2c2f036144ee085a5d1373d703a43a3e8e8fe..5823735dde9dfbfd0a975ac1747d0e87a3fea0bf 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -9828,6 +9828,15 @@ static void append_date(struct sip_request *req)
        add_header(req, "Date", tmpdat);
 }
 
+/*! \brief Append Retry-After header field when transmitting response */
+static int transmit_response_with_retry_after(struct sip_pvt *p, const char *msg, const struct sip_request *req, const char *seconds)
+{
+       struct sip_request resp;
+       respprep(&resp, p, msg, req);
+       add_header(&resp, "Retry-After", seconds);
+       return send_response(p, &resp, XMIT_UNRELIABLE, 0);
+}
+
 /*! \brief Append date and content length before transmitting response */
 static int transmit_response_with_date(struct sip_pvt *p, const char *msg, const struct sip_request *req)
 {
@@ -23511,10 +23520,16 @@ static int handle_incoming(struct sip_pvt *p, struct sip_request *req, struct as
        if (p->icseq && (p->icseq > seqno) ) {
                if (p->pendinginvite && seqno == p->pendinginvite && (req->method == SIP_ACK || req->method == SIP_CANCEL)) {
                        ast_debug(2, "Got CANCEL or ACK on INVITE with transactions in between.\n");
-               }  else {
+               } else {
                        ast_debug(1, "Ignoring too old SIP packet packet %d (expecting >= %d)\n", seqno, p->icseq);
-                       if (req->method != SIP_ACK)
+                       if (req->method == SIP_INVITE) {
+                               unsigned int ran = (ast_random() % 10) + 1;
+                               char seconds[4];
+                               snprintf(seconds, sizeof(seconds), "%u", ran);
+                               transmit_response_with_retry_after(p, "500 Server error", req, seconds);        /* respond according to RFC 3261 14.2 with Retry-After betwewn 0 and 10 */
+                       } else if (req->method != SIP_ACK) {
                                transmit_response(p, "500 Server error", req);  /* We must respond according to RFC 3261 sec 12.2 */
+                       }
                        return -1;
                }
        } else if (p->icseq &&