Example #1
0
/* Update single local media description to after receiving answer
 * from remote.
 */
static pj_status_t process_m_answer( pj_pool_t *pool,
				     pjmedia_sdp_media *offer,
				     pjmedia_sdp_media *answer,
				     pj_bool_t allow_asym)
{
    unsigned i;

    /* Check that the media type match our offer. */

    if (pj_strcmp(&answer->desc.media, &offer->desc.media)!=0) {
	/* The media type in the answer is different than the offer! */
	return PJMEDIA_SDPNEG_EINVANSMEDIA;
    }


    /* Check that transport in the answer match our offer. */

    /* At this point, transport type must be compatible, 
     * the transport instance will do more validation later.
     */
    if (pjmedia_sdp_transport_cmp(&answer->desc.transport, 
				  &offer->desc.transport) 
	!= PJ_SUCCESS)
    {
	return PJMEDIA_SDPNEG_EINVANSTP;
    }


    /* Check if remote has rejected our offer */
    
    if (answer->desc.port == 0) {
	
	/* Remote has rejected our offer. 
	 * Set our port to zero too in active SDP.
	 */
	offer->desc.port = 0;
    }


    /* Process direction attributes */
    update_media_direction(pool, answer, offer);
 
    /* If asymetric media is allowed, then just check that remote answer has 
     * codecs that are within the offer. 
     *
     * Otherwise if asymetric media is not allowed, then we will choose only
     * one codec in our initial offer to match the answer.
     */
    if (allow_asym) {
	for (i=0; i<answer->desc.fmt_count; ++i) {
	    unsigned j;
	    pj_str_t *rem_fmt = &answer->desc.fmt[i];

	    for (j=0; j<offer->desc.fmt_count; ++j) {
		if (pj_strcmp(rem_fmt, &answer->desc.fmt[j])==0)
		    break;
	    }

	    if (j != offer->desc.fmt_count) {
		/* Found at least one common codec. */
		break;
	    }
	}

	if (i == answer->desc.fmt_count) {
	    /* No common codec in the answer! */
	    return PJMEDIA_SDPNEG_EANSNOMEDIA;
	}

	PJ_TODO(CHECK_SDP_NEGOTIATION_WHEN_ASYMETRIC_MEDIA_IS_ALLOWED);

    } else {
	/* Remove all format in the offer that has no matching answer */
	for (i=0; i<offer->desc.fmt_count;) {
	    unsigned pt;
	    pj_uint32_t j;
	    pj_str_t *fmt = &offer->desc.fmt[i];
	    

	    /* Find matching answer */
	    pt = pj_strtoul(fmt);

	    if (pt < 96) {
		for (j=0; j<answer->desc.fmt_count; ++j) {
		    if (pj_strcmp(fmt, &answer->desc.fmt[j])==0)
			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_;

		/* Get the rtpmap for the payload type in the offer. */
		a = pjmedia_sdp_media_find_attr2(offer, "rtpmap", fmt);
		if (!a) {
		    pj_assert(!"Bug! Offer should have been validated");
		    return PJ_EBUG;
		}
		pjmedia_sdp_attr_get_rtpmap(a, &or_);

		/* Find paylaod in answer SDP with matching 
		 * encoding name and clock rate.
		 */
		for (j=0; j<answer->desc.fmt_count; ++j) {
		    a = pjmedia_sdp_media_find_attr2(answer, "rtpmap", 
						     &answer->desc.fmt[j]);
		    if (a) {
			pjmedia_sdp_rtpmap ar;
			pjmedia_sdp_attr_get_rtpmap(a, &ar);

			/* See if encoding name, clock rate, and channel
			 * count match 
			 */
			if (!pj_stricmp(&or_.enc_name, &ar.enc_name) &&
			    or_.clock_rate == ar.clock_rate &&
			    (pj_stricmp(&or_.param, &ar.param)==0 ||
			     (ar.param.slen==1 && *ar.param.ptr=='1')))
			{
			    /* Further check for G7221, negotiate bitrate. */
			    if (pj_strcmp2(&or_.enc_name, "G7221") == 0) {
				if (match_g7221(offer, i, answer, j))
				    break;
			    } else {
				/* Match! */
				break;
			    }
			}
		    }
		}
	    }

	    if (j == answer->desc.fmt_count) {
		/* This format has no matching answer.
		 * Remove it from our offer.
		 */
		pjmedia_sdp_attr *a;

		/* Remove rtpmap associated with this format */
		a = pjmedia_sdp_media_find_attr2(offer, "rtpmap", fmt);
		if (a)
		    pjmedia_sdp_media_remove_attr(offer, a);

		/* Remove fmtp associated with this format */
		a = pjmedia_sdp_media_find_attr2(offer, "fmtp", fmt);
		if (a)
		    pjmedia_sdp_media_remove_attr(offer, a);

		/* Remove this format from offer's array */
		pj_array_erase(offer->desc.fmt, sizeof(offer->desc.fmt[0]),
			       offer->desc.fmt_count, i);
		--offer->desc.fmt_count;

	    } else {
		++i;
	    }
	}

	/* Arrange format in the offer so the order match the priority
	 * in the answer
	 */
	for (i=0; i<answer->desc.fmt_count; ++i) {
	    unsigned j;
	    pj_str_t *fmt = &answer->desc.fmt[i];

	    for (j=i; j<offer->desc.fmt_count; ++j) {
		if (pj_strcmp(fmt, &offer->desc.fmt[j])==0) {
		    str_swap(&offer->desc.fmt[i], &offer->desc.fmt[j]);
		    break;
		}
	    }
	}
    }

    /* Looks okay */
    return PJ_SUCCESS;
}
Example #2
0
/* Try to match offer with answer. */
static pj_status_t match_offer(pj_pool_t *pool,
			       const pjmedia_sdp_media *offer,
			       const pjmedia_sdp_media *preanswer,
			       const pjmedia_sdp_media *orig_local,
			       pjmedia_sdp_media **p_answer)
{
    unsigned i;
    pj_bool_t offer_has_codec = 0,
	      offer_has_telephone_event = 0,
	      offer_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;

    /* With the addition of telephone-event and dodgy MS RTC SDP, 
     * the answer generation algorithm looks really shitty...
     */
    for (i=0; i<offer->desc.fmt_count; ++i) {
	unsigned j;
	
	if (pj_isdigit(*offer->desc.fmt[i].ptr)) {
	    /* This is normal/standard payload type, where it's identified
	     * by payload number.
	     */
	    unsigned pt;

	    pt = pj_strtoul(&offer->desc.fmt[i]);
	    
	    if (pt < 96) {
		/* For static payload type, it's enough to compare just
		 * the payload number.
		 */

		offer_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<preanswer->desc.fmt_count; ++j) {
		    unsigned p;
		    p = pj_strtoul(&preanswer->desc.fmt[j]);
		    if (p == pt && pj_isdigit(*preanswer->desc.fmt[j].ptr)) {
			found_matching_codec = 1;
			pt_answer[pt_answer_count++] = preanswer->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 offer. */
		a = pjmedia_sdp_media_find_attr2(offer, "rtpmap", 
						 &offer->desc.fmt[i]);
		if (!a) {
		    pj_assert(!"Bug! Offer should have been validated");
		    return PJMEDIA_SDP_EMISSINGRTPMAP;
		}
		pjmedia_sdp_attr_get_rtpmap(a, &or_);

		if (!pj_strcmp2(&or_.enc_name, "telephone-event")) {
		    offer_has_telephone_event = 1;
		    if (found_matching_telephone_event)
			continue;
		    is_codec = 0;
		} else {
		    offer_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<preanswer->desc.fmt_count; ++j) {
		    a = pjmedia_sdp_media_find_attr2(preanswer, "rtpmap", 
						     &preanswer->desc.fmt[j]);
		    if (a) {
			pjmedia_sdp_rtpmap lr;
			pjmedia_sdp_attr_get_rtpmap(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_strcmp(&or_.param, &lr.param)==0 ||
			     (or_.param.slen==1 && *or_.param.ptr=='1'))) 
			{
			    /* Match! */
			    if (is_codec) {
				/* Further check for G7221, negotiate bitrate. */
				if (pj_strcmp2(&or_.enc_name, "G7221")  == 0 &&
				    match_g7221(offer, i, preanswer, j) == 0)
				{
				    continue;
				}
				found_matching_codec = 1;
			    } else {
				found_matching_telephone_event = 1;
			    }

			    pt_answer[pt_answer_count++] = preanswer->desc.fmt[j];
			    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
	     */
	    offer_has_other = 1;
	    if (found_matching_other)
		continue;

	    for (j=0; j<preanswer->desc.fmt_count; ++j) {
		if (!pj_strcmp(&offer->desc.fmt[i], &preanswer->desc.fmt[j])) {
		    /* Match */
		    found_matching_other = 1;
		    pt_answer[pt_answer_count++] = preanswer->desc.fmt[j];
		    break;
		}
	    }
	}
    }

    /* See if all types of offer can be matched. */
    if (offer_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 (offer_has_other && !found_matching_other) {
	return PJMEDIA_SDPNEG_NOANSUNKNOWN;
    }

    /* Seems like everything is in order.
     * Build the answer by cloning from local media, but rearrange the payload
     * to suit the offer.
     */
    answer = pjmedia_sdp_media_clone(pool, orig_local);
    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]);
    }
    
    /* 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;

    /* If offer has zero port, set our answer with zero port too */
    if (offer->desc.port==0)
	answer->desc.port = 0;

    /* Update media direction. */
    update_media_direction(pool, offer, answer);

    *p_answer = answer;
    return PJ_SUCCESS;
}
Example #3
0
/* Update single local media description to after receiving answer
 * from remote.
 */
static pj_status_t process_m_answer( int inst_id,
					 pj_pool_t *pool,
				     pjmedia_sdp_media *offer,
				     pjmedia_sdp_media *answer,
				     pj_bool_t allow_asym)
{
    unsigned i;

    /* Check that the media type match our offer. */

    if (pj_strcmp(&answer->desc.media, &offer->desc.media)!=0) {
	/* The media type in the answer is different than the offer! */
	return PJMEDIA_SDPNEG_EINVANSMEDIA;
    }


    /* Check that transport in the answer match our offer. */

    /* At this point, transport type must be compatible, 
     * the transport instance will do more validation later.
     */
    if (pjmedia_sdp_transport_cmp(&answer->desc.transport, 
				  &offer->desc.transport) 
	!= PJ_SUCCESS)
    {
	return PJMEDIA_SDPNEG_EINVANSTP;
    }


    /* Check if remote has rejected our offer */
    if (answer->desc.port == 0) {
	
	/* Remote has rejected our offer. 
	 * Deactivate our media too.
	 */
	pjmedia_sdp_media_deactivate(pool, offer);

	/* Don't need to proceed */
	return PJ_SUCCESS;
    }

    /* Ticket #1148: check if remote answer does not set port to zero when
     * offered with port zero. Let's just tolerate it.
     */
    if (offer->desc.port == 0) {
	/* Don't need to proceed */
	return PJ_SUCCESS;
    }

    /* Process direction attributes */
    update_media_direction(pool, answer, offer);
 
    /* If asymetric media is allowed, then just check that remote answer has 
     * codecs that are within the offer. 
     *
     * Otherwise if asymetric media is not allowed, then we will choose only
     * one codec in our initial offer to match the answer.
     */
    if (allow_asym) {
	for (i=0; i<answer->desc.fmt_count; ++i) {
	    unsigned j;
	    pj_str_t *rem_fmt = &answer->desc.fmt[i];

	    for (j=0; j<offer->desc.fmt_count; ++j) {
		if (pj_strcmp(rem_fmt, &answer->desc.fmt[j])==0)
		    break;
	    }

	    if (j != offer->desc.fmt_count) {
		/* Found at least one common codec. */
		break;
	    }
	}

	if (i == answer->desc.fmt_count) {
	    /* No common codec in the answer! */
	    return PJMEDIA_SDPNEG_EANSNOMEDIA;
	}

	PJ_TODO(CHECK_SDP_NEGOTIATION_WHEN_ASYMETRIC_MEDIA_IS_ALLOWED);

    } else {
	/* Offer format priority based on answer format index/priority */
	unsigned offer_fmt_prior[PJMEDIA_MAX_SDP_FMT];

	/* Remove all format in the offer that has no matching answer */
	for (i=0; i<offer->desc.fmt_count;) {
	    unsigned pt;
	    pj_uint32_t j;
	    pj_str_t *fmt = &offer->desc.fmt[i];
	    

	    /* Find matching answer */
	    pt = pj_strtoul(fmt);

	    if (pt < 96 || pt == 5000) {  // dean : 5000 is for WebRTC data channel.
		for (j=0; j<answer->desc.fmt_count; ++j) {
		    if (pj_strcmp(fmt, &answer->desc.fmt[j])==0)
			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_;

		/* Get the rtpmap for the payload type in the offer. */
		a = pjmedia_sdp_media_find_attr2(offer, "rtpmap", fmt);
		if (!a) {
		    pj_assert(!"Bug! Offer should have been validated");
		    return PJ_EBUG;
		}
		pjmedia_sdp_attr_get_rtpmap(inst_id, a, &or_);

		/* Find paylaod in answer SDP with matching 
		 * encoding name and clock rate.
		 */
		for (j=0; j<answer->desc.fmt_count; ++j) {
		    a = pjmedia_sdp_media_find_attr2(answer, "rtpmap", 
						     &answer->desc.fmt[j]);
		    if (a) {
			pjmedia_sdp_rtpmap ar;
			pjmedia_sdp_attr_get_rtpmap(inst_id, a, &ar);

			/* See if encoding name, clock rate, and channel
			 * count match 
			 */
			if (!pj_stricmp(&or_.enc_name, &ar.enc_name) &&
			    or_.clock_rate == ar.clock_rate &&
			    (pj_stricmp(&or_.param, &ar.param)==0 ||
			     (ar.param.slen==1 && *ar.param.ptr=='1')))
			{
			    /* Further check for G7221, negotiate bitrate. */
			    if (pj_stricmp2(&or_.enc_name, "G7221") == 0) {
				if (match_g7221(offer, i, answer, j))
				    break;
			    } else
			    /* Further check for AMR, negotiate fmtp. */
			    if (pj_stricmp2(&or_.enc_name, "AMR") == 0 ||
				pj_stricmp2(&or_.enc_name, "AMR-WB") == 0) 
			    {
				if (match_amr(offer, i, answer, j, PJ_FALSE, 
					      NULL))
				    break;
			    } else {
				/* Match! */
				break;
			    }
			}
		    }
		}
	    }

	    if (j == answer->desc.fmt_count) {
		/* This format has no matching answer.
		 * Remove it from our offer.
		 */
		pjmedia_sdp_attr *a;

		/* Remove rtpmap associated with this format */
		a = pjmedia_sdp_media_find_attr2(offer, "rtpmap", fmt);
		if (a)
		    pjmedia_sdp_media_remove_attr(offer, a);

		/* Remove fmtp associated with this format */
		a = pjmedia_sdp_media_find_attr2(offer, "fmtp", fmt);
		if (a)
		    pjmedia_sdp_media_remove_attr(offer, a);

		/* Remove this format from offer's array */
		pj_array_erase(offer->desc.fmt, sizeof(offer->desc.fmt[0]),
			       offer->desc.fmt_count, i);
		--offer->desc.fmt_count;

	    } else {
		offer_fmt_prior[i] = j;
		++i;
	    }
	}

	if (0 == offer->desc.fmt_count) {
	    /* No common codec in the answer! */
	    return PJMEDIA_SDPNEG_EANSNOMEDIA;
	}

	/* Post process:
	 * - Resort offer formats so the order match to the answer.
	 * - Remove answer formats that unmatches to the offer.
	 */
	
	/* Resort offer formats */
	for (i=0; i<offer->desc.fmt_count; ++i) {
	    unsigned j;
	    for (j=i+1; j<offer->desc.fmt_count; ++j) {
		if (offer_fmt_prior[i] > offer_fmt_prior[j]) {
		    unsigned tmp = offer_fmt_prior[i];
		    offer_fmt_prior[i] = offer_fmt_prior[j];
		    offer_fmt_prior[j] = tmp;
		    str_swap(&offer->desc.fmt[i], &offer->desc.fmt[j]);
		}
	    }
	}

	/* Remove unmatched answer formats */
	{
	    unsigned del_cnt = 0;
	    for (i=0; i<answer->desc.fmt_count;) {
		/* The offer is ordered now, also the offer_fmt_prior */
		if (i >= offer->desc.fmt_count || 
		    offer_fmt_prior[i]-del_cnt != i)
		{
		    pj_str_t *fmt = &answer->desc.fmt[i];
		    pjmedia_sdp_attr *a;

		    /* Remove rtpmap associated with this format */
		    a = pjmedia_sdp_media_find_attr2(answer, "rtpmap", fmt);
		    if (a)
			pjmedia_sdp_media_remove_attr(answer, a);

		    /* Remove fmtp associated with this format */
		    a = pjmedia_sdp_media_find_attr2(answer, "fmtp", fmt);
		    if (a)
			pjmedia_sdp_media_remove_attr(answer, a);

		    /* Remove this format from answer's array */
		    pj_array_erase(answer->desc.fmt, 
				   sizeof(answer->desc.fmt[0]),
				   answer->desc.fmt_count, i);
		    --answer->desc.fmt_count;

		    ++del_cnt;
		} else {
		    ++i;
		}
	    }
	}
    }

    /* Looks okay */
    return PJ_SUCCESS;
}