Fix several bugs with SDP parsing and well-formedness of responses

Fix bug ASTERISK-16558 which dealt with the order of responses to incoming
streams defined by SDP.

Fix unreported bug where offering multiple same-type streams would cause
Asterisk to reply with an incorrect SDP response missing one or more streams
without a proper declination.

Fix bugs related to a single non-audio stream being offered with responses
requesting codecs that were not offered in the initial invite along with an
additional audio stream that was not in the initial invite.

Review: https://reviewboard.asterisk.org/r/1516/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@344385 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 6ff92a7acb66418d3bccc84bacaf7dbc65f3cd9a..b098570519b9a606e04782bd8b8ed590b87b1633 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -8841,9 +8841,12 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                                ast_log(LOG_WARNING, "unknown SDP media protocol in offer: %s\n", protocol);
                                continue;
                        }
+                       if (p->offered_media[SDP_AUDIO].order_offered) {
+                               ast_log(LOG_WARNING, "Multiple audio streams are not supported\n");
+                               return -3;
+                       }
                        audio = TRUE;
-                       p->offered_media[SDP_AUDIO].offered = TRUE;
-                       numberofmediastreams++;
+                       p->offered_media[SDP_AUDIO].order_offered = ++numberofmediastreams;
                        portno = x;
 
                        /* Scan through the RTP payload types specified in a "m=" line: */
@@ -8868,10 +8871,13 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                                ast_log(LOG_WARNING, "unknown SDP media protocol in offer: %s\n", protocol);
                                continue;
                        }
+                       if (p->offered_media[SDP_VIDEO].order_offered) {
+                               ast_log(LOG_WARNING, "Multiple video streams are not supported\n");
+                               return -3;
+                       }
                        video = TRUE;
                        p->novideo = FALSE;
-                       p->offered_media[SDP_VIDEO].offered = TRUE;
-                       numberofmediastreams++;
+                       p->offered_media[SDP_VIDEO].order_offered = ++numberofmediastreams;
                        vportno = x;
 
                        /* Scan through the RTP payload types specified in a "m=" line: */
@@ -8889,10 +8895,13 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                /* Search for text media definition */
                } else if ((sscanf(m, "text %30u/%30u RTP/AVP %n", &x, &numberofports, &len) == 2 && len > 0 && x) ||
                           (sscanf(m, "text %30u RTP/AVP %n", &x, &len) == 1 && len > 0 && x)) {
+                       if (p->offered_media[SDP_TEXT].order_offered) {
+                               ast_log(LOG_WARNING, "Multiple text streams are not supported\n");
+                               return -3;
+                       }
                        text = TRUE;
                        p->notext = FALSE;
-                       p->offered_media[SDP_TEXT].offered = TRUE;
-                       numberofmediastreams++;
+                       p->offered_media[SDP_TEXT].order_offered = ++numberofmediastreams;
                        tportno = x;
 
                        /* Scan through the RTP payload types specified in a "m=" line: */
@@ -8910,12 +8919,15 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                /* Search for image media definition */
                } else if (p->udptl && ((sscanf(m, "image %30u udptl t38%n", &x, &len) == 1 && len > 0 && x) ||
                                        (sscanf(m, "image %30u UDPTL t38%n", &x, &len) == 1 && len > 0 && x) )) {
+                       if (p->offered_media[SDP_IMAGE].order_offered) {
+                               ast_log(LOG_WARNING, "Multiple T.38 streams are not supported\n");
+                               return -3;
+                       }
                        image = TRUE;
                        if (debug)
                                ast_verbose("Got T.38 offer in SDP in dialog %s\n", p->callid);
-                       p->offered_media[SDP_IMAGE].offered = TRUE;
+                       p->offered_media[SDP_IMAGE].order_offered = ++numberofmediastreams;
                        udptlportno = x;
-                       numberofmediastreams++;
 
                        if (p->t38.state != T38_ENABLED) {
                                memset(&p->t38.their_parms, 0, sizeof(p->t38.their_parms));
@@ -9016,12 +9028,6 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                return -2;
        }
 
-       if (numberofmediastreams > 3) {
-               /* We have too many fax, audio and/or video and/or text media streams, fail this offer */
-               ast_log(LOG_WARNING, "Faling due to too many media streams\n");
-               return -3;
-       }
-
        if (secure_audio && !(p->srtp && (ast_test_flag(p->srtp, SRTP_CRYPTO_OFFER_OK)))) {
                ast_log(LOG_WARNING, "Can't provide secure audio requested in SDP offer\n");
                return -4;
@@ -9081,12 +9087,23 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                            ast_rtp_lookup_mime_multiple2(s2, peernoncodeccapability, 0, 0),
                            ast_rtp_lookup_mime_multiple2(s3, newnoncodeccapability, 0, 0));
        }
-       if (!newjointcapability && (portno != -1)) {
+       if (!newjointcapability && udptlportno == -1) {
                ast_log(LOG_NOTICE, "No compatible codecs, not accepting this offer!\n");
                /* Do NOT Change current setting */
                return -1;
        }
 
+       /* We are now ready to change the sip session and p->rtp and p->vrtp with the offered codecs, since
+          they are acceptable */
+       p->jointcapability = newjointcapability;                /* Our joint codec profile for this call */
+       p->peercapability = newpeercapability;                  /* The other sides capability in latest offer */
+       p->jointnoncodeccapability = newnoncodeccapability;     /* DTMF capabilities */
+
+       /* respond with single most preferred joint codec, limiting the other side's choice */
+       if (ast_test_flag(&p->flags[1], SIP_PAGE2_PREFERRED_CODEC)) {
+               p->jointcapability = ast_codec_choose(&p->prefs, p->jointcapability, 1);
+       }
+
        /* Setup audio address and port */
        if (p->rtp) {
                if (portno > 0) {
@@ -9096,15 +9113,6 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
                                ast_verbose("Peer audio RTP is at port %s\n",
                                            ast_sockaddr_stringify(sa));
                        }
-                       /* We are now ready to change the sip session and p->rtp and p->vrtp with the offered codecs, since
-                          they are acceptable */
-                       p->jointcapability = newjointcapability;                /* Our joint codec profile for this call */
-                       p->peercapability = newpeercapability;                  /* The other sides capability in latest offer */
-                       p->jointnoncodeccapability = newnoncodeccapability;     /* DTMF capabilities */
-
-                       if (ast_test_flag(&p->flags[1], SIP_PAGE2_PREFERRED_CODEC)) { /* respond with single most preferred joint codec, limiting the other side's choice */
-                               p->jointcapability = ast_codec_choose(&p->prefs, p->jointcapability, 1);
-                       }
 
                        ast_rtp_codecs_payloads_copy(&newaudiortp, ast_rtp_instance_get_codecs(p->rtp), p->rtp);
                        /* Ensure RTCP is enabled since it may be inactive
@@ -11405,47 +11413,94 @@ static enum sip_result add_sdp(struct sip_request *resp, struct sip_pvt *p, int
        add_content(resp, owner);
        add_content(resp, subject);
        add_content(resp, connection);
-       if (needvideo)          /* only if video response is appropriate */
+       /* only if video response is appropriate */
+       if (needvideo) {
                add_content(resp, bandwidth);
-       add_content(resp, session_time);
-       if (needaudio) {
-               add_content(resp, m_audio->str);
-               add_content(resp, a_audio->str);
-               add_content(resp, hold);
-               if (a_crypto) {
-                       add_content(resp, a_crypto);
-               }
-       } else if (p->offered_media[SDP_AUDIO].offered) {
-               snprintf(dummy_answer, sizeof(dummy_answer), "m=audio 0 RTP/AVP %s\r\n", p->offered_media[SDP_AUDIO].codecs);
-               add_content(resp, dummy_answer);
-       }
-       if (needvideo) { /* only if video response is appropriate */
-               add_content(resp, m_video->str);
-               add_content(resp, a_video->str);
-               add_content(resp, hold);        /* Repeat hold for the video stream */
-               if (v_a_crypto) {
-                       add_content(resp, v_a_crypto);
-               }
-       } else if (p->offered_media[SDP_VIDEO].offered) {
-               snprintf(dummy_answer, sizeof(dummy_answer), "m=video 0 RTP/AVP %s\r\n", p->offered_media[SDP_VIDEO].codecs);
-               add_content(resp, dummy_answer);
-       }
-       if (needtext) { /* only if text response is appropriate */
-               add_content(resp, m_text->str);
-               add_content(resp, a_text->str);
-               add_content(resp, hold);        /* Repeat hold for the text stream */
-               if (t_a_crypto) {
-                       add_content(resp, t_a_crypto);
-               }
-       } else if (p->offered_media[SDP_TEXT].offered) {
-               snprintf(dummy_answer, sizeof(dummy_answer), "m=text 0 RTP/AVP %s\r\n", p->offered_media[SDP_TEXT].codecs);
-               add_content(resp, dummy_answer);
        }
-       if (add_t38) {
-               add_content(resp, m_modem->str);
-               add_content(resp, a_modem->str);
-       } else if (p->offered_media[SDP_IMAGE].offered) {
-               add_content(resp, "m=image 0 udptl t38\r\n");
+       add_content(resp, session_time);
+       /* if this is a response to an invite, order our offers properly */
+       if (p->offered_media[SDP_AUDIO].order_offered ||
+               p->offered_media[SDP_VIDEO].order_offered ||
+               p->offered_media[SDP_TEXT].order_offered ||
+               p->offered_media[SDP_IMAGE].order_offered) {
+               int i;
+               /* we have up to 3 streams as limited by process_sdp */
+               for (i = 1; i <= 3; i++) {
+                       if (p->offered_media[SDP_AUDIO].order_offered == i) {
+                               if (needaudio) {
+                                       add_content(resp, m_audio->str);
+                                       add_content(resp, a_audio->str);
+                                       add_content(resp, hold);
+                                       if (a_crypto) {
+                                               add_content(resp, a_crypto);
+                                       }
+                               } else {
+                                       snprintf(dummy_answer, sizeof(dummy_answer), "m=audio 0 RTP/AVP %s\r\n", p->offered_media[SDP_AUDIO].codecs);
+                                       add_content(resp, dummy_answer);
+                               }
+                       } else if (p->offered_media[SDP_VIDEO].order_offered == i) {
+                               if (needvideo) { /* only if video response is appropriate */
+                                       add_content(resp, m_video->str);
+                                       add_content(resp, a_video->str);
+                                       add_content(resp, hold);        /* Repeat hold for the video stream */
+                                       if (v_a_crypto) {
+                                               add_content(resp, v_a_crypto);
+                                       }
+                               } else {
+                                       snprintf(dummy_answer, sizeof(dummy_answer), "m=video 0 RTP/AVP %s\r\n", p->offered_media[SDP_VIDEO].codecs);
+                                       add_content(resp, dummy_answer);
+                               }
+                       } else if (p->offered_media[SDP_TEXT].order_offered == i) {
+                               if (needtext) { /* only if text response is appropriate */
+                                       add_content(resp, m_text->str);
+                                       add_content(resp, a_text->str);
+                                       add_content(resp, hold);        /* Repeat hold for the text stream */
+                                       if (t_a_crypto) {
+                                               add_content(resp, t_a_crypto);
+                                       }
+                               } else {
+                                       snprintf(dummy_answer, sizeof(dummy_answer), "m=text 0 RTP/AVP %s\r\n", p->offered_media[SDP_TEXT].codecs);
+                                       add_content(resp, dummy_answer);
+                               }
+                       } else if (p->offered_media[SDP_IMAGE].order_offered == i) {
+                               if (add_t38) {
+                                       add_content(resp, m_modem->str);
+                                       add_content(resp, a_modem->str);
+                               } else {
+                                       add_content(resp, "m=image 0 udptl t38\r\n");
+                               }
+                       }
+               }
+       } else {
+               /* generate new SDP from scratch, no offers */
+               if (needaudio) {
+                       add_content(resp, m_audio->str);
+                       add_content(resp, a_audio->str);
+                       add_content(resp, hold);
+                       if (a_crypto) {
+                               add_content(resp, a_crypto);
+                       }
+               }
+               if (needvideo) { /* only if video response is appropriate */
+                       add_content(resp, m_video->str);
+                       add_content(resp, a_video->str);
+                       add_content(resp, hold);        /* Repeat hold for the video stream */
+                       if (v_a_crypto) {
+                               add_content(resp, v_a_crypto);
+                       }
+               }
+               if (needtext) { /* only if text response is appropriate */
+                       add_content(resp, m_text->str);
+                       add_content(resp, a_text->str);
+                       add_content(resp, hold);        /* Repeat hold for the text stream */
+                       if (t_a_crypto) {
+                               add_content(resp, t_a_crypto);
+                       }
+               }
+               if (add_t38) {
+                       add_content(resp, m_modem->str);
+                       add_content(resp, a_modem->str);
+               }
        }
 
        /* Update lastrtprx when we send our SDP */

diff --git a/channels/sip/include/sip.h b/channels/sip/include/sip.h
index c99de34854c7d850852c237a607b63d1361e6c9c..c5b8d0b6ff60eddbcda3a7621bb97e9117d0e647 100644 (file)
--- a/channels/sip/include/sip.h
+++ b/channels/sip/include/sip.h
@@ -913,7 +913,7 @@ struct sip_st_cfg {
 /*! \brief Structure for remembering offered media in an INVITE, to make sure we reply
        to all media streams. In theory. In practise, we try our best. */
 struct offered_media {
-       int offered;
+       int order_offered;              /*!< Order the media was offered in. Not offered is 0 */
        char codecs[128];
 };