static pjmedia_sdp_media *sdp_media_clone_deactivate( pj_pool_t *pool, const pjmedia_sdp_media *rem_med, const pjmedia_sdp_media *local_med, const pjmedia_sdp_session *local_sess) { pjmedia_sdp_media *res; res = pjmedia_sdp_media_clone_deactivate(pool, rem_med); if (!res) return NULL; if (!res->conn && (!local_sess || !local_sess->conn)) { if (local_med && local_med->conn) res->conn = pjmedia_sdp_conn_clone(pool, local_med->conn); else { res->conn = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_conn); res->conn->net_type = pj_str("IN"); res->conn->addr_type = pj_str("IP4"); res->conn->addr = pj_str("127.0.0.1"); } } return res; }
/* Update local media session (offer) to create active local session * after receiving remote answer. */ static pj_status_t process_answer(int inst_id, pj_pool_t *pool, pjmedia_sdp_session *offer, pjmedia_sdp_session *answer, pj_bool_t allow_asym, pjmedia_sdp_session **p_active) { unsigned omi = 0; /* Offer media index */ unsigned ami = 0; /* Answer media index */ pj_bool_t has_active = PJ_FALSE; pj_status_t status; /* Check arguments. */ PJ_ASSERT_RETURN(pool && offer && answer && p_active, PJ_EINVAL); /* Check that media count match between offer and answer */ // Ticket #527, different media count is allowed for more interoperability, // however, the media order must be same between offer and answer. // if (offer->media_count != answer->media_count) // return PJMEDIA_SDPNEG_EMISMEDIA; /* Now update each media line in the offer with the answer. */ for (; omi<offer->media_count; ++omi) { if (ami == answer->media_count) { /* The answer has less media than the offer */ pjmedia_sdp_media *am; /* Generate matching-but-disabled-media for the answer */ am = pjmedia_sdp_media_clone_deactivate(pool, offer->media[omi]); answer->media[answer->media_count++] = am; ++ami; /* Deactivate our media offer too */ pjmedia_sdp_media_deactivate(pool, offer->media[omi]); /* No answer media to be negotiated */ continue; } status = process_m_answer(inst_id, pool, offer->media[omi], answer->media[ami], allow_asym); /* If media type is mismatched, just disable the media. */ if (status == PJMEDIA_SDPNEG_EINVANSMEDIA) { pjmedia_sdp_media_deactivate(pool, offer->media[omi]); continue; } /* No common format in the answer media. */ else if (status == PJMEDIA_SDPNEG_EANSNOMEDIA) { pjmedia_sdp_media_deactivate(pool, offer->media[omi]); pjmedia_sdp_media_deactivate(pool, answer->media[ami]); } /* Return the error code, for other errors. */ else if (status != PJ_SUCCESS) { return status; } if (offer->media[omi]->desc.port != 0) has_active = PJ_TRUE; ++ami; } *p_active = offer; return has_active ? PJ_SUCCESS : PJMEDIA_SDPNEG_ENOMEDIA; }
/* Create complete answer for remote's offer. */ static pj_status_t create_answer( int inst_id, pj_pool_t *pool, pj_bool_t prefer_remote_codec_order, const pjmedia_sdp_session *initial, const pjmedia_sdp_session *offer, pjmedia_sdp_session **p_answer) { pj_status_t status = PJMEDIA_SDPNEG_ENOMEDIA; pj_bool_t has_active = PJ_FALSE; pjmedia_sdp_session *answer; char media_used[PJMEDIA_MAX_SDP_MEDIA]; unsigned i; /* Validate remote offer. * This should have been validated before. */ PJ_ASSERT_RETURN((status=pjmedia_sdp_validate(offer))==PJ_SUCCESS, status); /* Create initial answer by duplicating initial SDP, * but clear all media lines. The media lines will be filled up later. */ answer = pjmedia_sdp_session_clone(pool, initial); PJ_ASSERT_RETURN(answer != NULL, PJ_ENOMEM); answer->media_count = 0; pj_bzero(media_used, sizeof(media_used)); /* For each media line, create our answer based on our initial * capability. */ for (i=0; i<offer->media_count; ++i) { const pjmedia_sdp_media *om; /* offer */ const pjmedia_sdp_media *im; /* initial media */ pjmedia_sdp_media *am = NULL; /* answer/result */ unsigned j; om = offer->media[i]; /* Find media description in our initial capability that matches * the media type and transport type of offer's media, has * matching codec, and has not been used to answer other offer. */ for (im=NULL, j=0; j<initial->media_count; ++j) { im = initial->media[j]; if (pj_strcmp(&om->desc.media, &im->desc.media)==0 && pj_strcmp(&om->desc.transport, &im->desc.transport)==0 && media_used[j] == 0) { /* See if it has matching codec. */ status = match_offer(inst_id, pool, prefer_remote_codec_order, om, im, &am); if (status == PJ_SUCCESS) { /* Mark media as used. */ media_used[j] = 1; break; } } } if (j==initial->media_count) { /* No matching media. * Reject the offer by setting the port to zero in the answer. */ /* For simplicity in the construction of the answer, we'll * just clone the media from the offer. Anyway receiver will * ignore anything in the media once it sees that the port * number is zero. */ am = pjmedia_sdp_media_clone_deactivate(pool, om); } else { /* The answer is in am */ pj_assert(am != NULL); } /* Add the media answer */ answer->media[answer->media_count++] = am; /* Check if this media is active.*/ if (am->desc.port != 0) has_active = PJ_TRUE; } *p_answer = answer; return has_active ? PJ_SUCCESS : status; }
/* * Modify local SDP and wait for remote answer. */ PJ_DEF(pj_status_t) pjmedia_sdp_neg_modify_local_offer( pj_pool_t *pool, pjmedia_sdp_neg *neg, const pjmedia_sdp_session *local) { pjmedia_sdp_session *new_offer; pjmedia_sdp_session *old_offer; char media_used[PJMEDIA_MAX_SDP_MEDIA]; unsigned oi; /* old offer media index */ pj_status_t status; /* Check arguments are valid. */ PJ_ASSERT_RETURN(pool && neg && local, PJ_EINVAL); /* Can only do this in STATE_DONE. */ PJ_ASSERT_RETURN(neg->state == PJMEDIA_SDP_NEG_STATE_DONE, PJMEDIA_SDPNEG_EINSTATE); /* Validate the new offer */ status = pjmedia_sdp_validate(local); if (status != PJ_SUCCESS) return status; /* Change state to STATE_LOCAL_OFFER */ neg->state = PJMEDIA_SDP_NEG_STATE_LOCAL_OFFER; /* Init vars */ pj_bzero(media_used, sizeof(media_used)); old_offer = neg->active_local_sdp; new_offer = pjmedia_sdp_session_clone(pool, local); /* RFC 3264 Section 8: When issuing an offer that modifies the session, * the "o=" line of the new SDP MUST be identical to that in the * previous SDP, except that the version in the origin field MUST * increment by one from the previous SDP. */ pj_strdup(pool, &new_offer->origin.user, &old_offer->origin.user); new_offer->origin.id = old_offer->origin.id; new_offer->origin.version = old_offer->origin.version + 1; pj_strdup(pool, &new_offer->origin.net_type, &old_offer->origin.net_type); pj_strdup(pool, &new_offer->origin.addr_type,&old_offer->origin.addr_type); pj_strdup(pool, &new_offer->origin.addr, &old_offer->origin.addr); /* Generating the new offer, in the case media lines doesn't match the * active SDP (e.g. current/active SDP's have m=audio and m=video lines, * and the new offer only has m=audio line), the negotiator will fix * the new offer by reordering and adding the missing media line with * port number set to zero. */ for (oi = 0; oi < old_offer->media_count; ++oi) { pjmedia_sdp_media *om; pjmedia_sdp_media *nm; unsigned ni; /* new offer media index */ pj_bool_t found = PJ_FALSE; om = old_offer->media[oi]; for (ni = oi; ni < new_offer->media_count; ++ni) { nm = new_offer->media[ni]; if (pj_strcmp(&nm->desc.media, &om->desc.media) == 0) { if (ni != oi) { /* The same media found but the position unmatched to the * old offer, so let's put this media in the right place, * and keep the order of the rest. */ pj_array_insert(new_offer->media, /* array */ sizeof(new_offer->media[0]), /* elmt size*/ ni, /* count */ oi, /* pos */ &nm); /* new elmt */ } found = PJ_TRUE; break; } } if (!found) { pjmedia_sdp_media *m; m = pjmedia_sdp_media_clone_deactivate(pool, om); pj_array_insert(new_offer->media, sizeof(new_offer->media[0]), new_offer->media_count++, oi, &m); } } /* New_offer fixed */ neg->initial_sdp = new_offer; neg->neg_local_sdp = pjmedia_sdp_session_clone(pool, new_offer); return PJ_SUCCESS; }
/* Try to match offer with answer. */ static pj_status_t match_offer(int inst_id, pj_pool_t *pool, pj_bool_t prefer_remote_codec_order, const pjmedia_sdp_media *offer, const pjmedia_sdp_media *preanswer, pjmedia_sdp_media **p_answer) { unsigned i; pj_bool_t master_has_codec = 0, master_has_telephone_event = 0, master_has_other = 0, found_matching_codec = 0, found_matching_telephone_event = 0, found_matching_other = 0; unsigned pt_answer_count = 0; pj_str_t pt_answer[PJMEDIA_MAX_SDP_FMT]; pjmedia_sdp_media *answer; const pjmedia_sdp_media *master, *slave; pj_str_t pt_amr_need_adapt = {NULL, 0}; /* If offer has zero port, just clone the offer */ if (offer->desc.port == 0) { answer = pjmedia_sdp_media_clone_deactivate(pool, offer); *p_answer = answer; return PJ_SUCCESS; } /* Set master/slave negotiator based on prefer_remote_codec_order. */ if (prefer_remote_codec_order) { master = offer; slave = preanswer; } else { master = preanswer; slave = offer; } /* With the addition of telephone-event and dodgy MS RTC SDP, * the answer generation algorithm looks really shitty... */ for (i=0; i<master->desc.fmt_count; ++i) { unsigned j; if (pj_isdigit(*master->desc.fmt[i].ptr)) { /* This is normal/standard payload type, where it's identified * by payload number. */ unsigned pt; pt = pj_strtoul(&master->desc.fmt[i]); if (pt < 96 || pt == 5000) { // dean : 5000 is for WebRTC data channel. /* For static payload type, it's enough to compare just * the payload number. */ master_has_codec = 1; /* We just need to select one codec. * Continue if we have selected matching codec for previous * payload. */ if (found_matching_codec) continue; /* Find matching codec in local descriptor. */ for (j=0; j<slave->desc.fmt_count; ++j) { unsigned p; p = pj_strtoul(&slave->desc.fmt[j]); if (p == pt && pj_isdigit(*slave->desc.fmt[j].ptr)) { found_matching_codec = 1; pt_answer[pt_answer_count++] = slave->desc.fmt[j]; break; } } } else { /* This is dynamic payload type. * For dynamic payload type, we must look the rtpmap and * compare the encoding name. */ const pjmedia_sdp_attr *a; pjmedia_sdp_rtpmap or_; pj_bool_t is_codec; /* Get the rtpmap for the payload type in the master. */ a = pjmedia_sdp_media_find_attr2(master, "rtpmap", &master->desc.fmt[i]); if (!a) { pj_assert(!"Bug! Offer should have been validated"); return PJMEDIA_SDP_EMISSINGRTPMAP; } pjmedia_sdp_attr_get_rtpmap(inst_id, a, &or_); if (!pj_stricmp2(&or_.enc_name, "telephone-event")) { master_has_telephone_event = 1; if (found_matching_telephone_event) continue; is_codec = 0; } else { master_has_codec = 1; if (found_matching_codec) continue; is_codec = 1; } /* Find paylaod in our initial SDP with matching * encoding name and clock rate. */ for (j=0; j<slave->desc.fmt_count; ++j) { a = pjmedia_sdp_media_find_attr2(slave, "rtpmap", &slave->desc.fmt[j]); if (a) { pjmedia_sdp_rtpmap lr; pjmedia_sdp_attr_get_rtpmap(inst_id, a, &lr); /* See if encoding name, clock rate, and * channel count match */ if (!pj_stricmp(&or_.enc_name, &lr.enc_name) && or_.clock_rate == lr.clock_rate && (pj_stricmp(&or_.param, &lr.param)==0 || (lr.param.slen==0 && or_.param.slen==1 && *or_.param.ptr=='1') || (or_.param.slen==0 && lr.param.slen==1 && *lr.param.ptr=='1'))) { /* Match! */ if (is_codec) { /* Further check for G7221, negotiate bitrate */ if (pj_stricmp2(&or_.enc_name, "G7221") == 0 && !match_g7221(master, i, slave, j)) { continue; } else /* Further check for AMR, negotiate fmtp */ if (pj_stricmp2(&or_.enc_name, "AMR")==0 || pj_stricmp2(&or_.enc_name, "AMR-WB")==0) { unsigned o_med_idx, a_med_idx; o_med_idx = prefer_remote_codec_order? i:j; a_med_idx = prefer_remote_codec_order? j:i; if (!match_amr(offer, o_med_idx, preanswer, a_med_idx, PJ_TRUE, &pt_amr_need_adapt)) continue; } found_matching_codec = 1; } else { found_matching_telephone_event = 1; } pt_answer[pt_answer_count++] = prefer_remote_codec_order? preanswer->desc.fmt[j]: preanswer->desc.fmt[i]; break; } } } } } else { /* This is a non-standard, brain damaged SDP where the payload * type is non-numeric. It exists e.g. in Microsoft RTC based * UA, to indicate instant messaging capability. * Example: * - m=x-ms-message 5060 sip null */ master_has_other = 1; if (found_matching_other) continue; for (j=0; j<slave->desc.fmt_count; ++j) { if (!pj_strcmp(&master->desc.fmt[i], &slave->desc.fmt[j])) { /* Match */ found_matching_other = 1; pt_answer[pt_answer_count++] = prefer_remote_codec_order? preanswer->desc.fmt[j]: preanswer->desc.fmt[i]; break; } } } } /* See if all types of master can be matched. */ if (master_has_codec && !found_matching_codec) { return PJMEDIA_SDPNEG_NOANSCODEC; } /* If this comment is removed, negotiation will fail if remote has offered telephone-event and local is not configured with telephone-event if (offer_has_telephone_event && !found_matching_telephone_event) { return PJMEDIA_SDPNEG_NOANSTELEVENT; } */ if (master_has_other && !found_matching_other) { return PJMEDIA_SDPNEG_NOANSUNKNOWN; } /* Seems like everything is in order. * Build the answer by cloning from preanswer, but rearrange the payload * to suit the offer. */ answer = pjmedia_sdp_media_clone(pool, preanswer); for (i=0; i<pt_answer_count; ++i) { unsigned j; for (j=i; j<answer->desc.fmt_count; ++j) { if (!pj_strcmp(&answer->desc.fmt[j], &pt_answer[i])) break; } pj_assert(j != answer->desc.fmt_count); str_swap(&answer->desc.fmt[i], &answer->desc.fmt[j]); /* For AMR/AMRWB format, adapt octet-align setting if required. */ if (!pj_strcmp(&pt_amr_need_adapt, &pt_answer[i])) amr_toggle_octet_align(pool, answer, i); } /* Remove unwanted local formats. */ for (i=pt_answer_count; i<answer->desc.fmt_count; ++i) { pjmedia_sdp_attr *a; /* Remove rtpmap for this format */ a = pjmedia_sdp_media_find_attr2(answer, "rtpmap", &answer->desc.fmt[i]); if (a) { pjmedia_sdp_media_remove_attr(answer, a); } /* Remove fmtp for this format */ a = pjmedia_sdp_media_find_attr2(answer, "fmtp", &answer->desc.fmt[i]); if (a) { pjmedia_sdp_media_remove_attr(answer, a); } } answer->desc.fmt_count = pt_answer_count; /* Update media direction. */ update_media_direction(pool, offer, answer); *p_answer = answer; return PJ_SUCCESS; }