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;
}
