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res_pjsip_session/res_pjsip_sdp_rtp: Be more tolerant of offers

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When an inbound SDP offer is received, Asterisk currently makes a few
incorrection assumptions:

(1) If the offer contains more than a single audio/video stream, Asterisk will
    reject the entire stream with a 488. This is an overly strict response;
    generally, Asterisk should accept the media streams that it can accept and
    decline the others.
(2) If the offer contains a declined media stream, Asterisk will attempt to
    process it anyway. This can result in attempting to match format
    capabilities on a declined media stream, leading to a 488. Asterisk should
    simply ignore declined media streams.
(3) Asterisk will currently attempt to handle offers with AVPF with
    use_avpf=No/AVP with use_avpf=Yes. This mismatch results in invalid SDP
    answers being sent in response. If there is a mismatch between the media
    type being offered and the configuration, Asterisk must reject the offer
    with a 488.

This patch does the following:
* Asterisk will accept SDP offers with at least one media stream that it can
  use. Some WARNING messages have been dropped to NOTICEs as a result.
* Asterisk will not accept an offer with a media type that doesn't match its
  configuration.
* Asterisk will ignore declined media streams properly.

#SIPit31

Review: https://reviewboard.asterisk.org/r/4063/

ASTERISK-24122 #close
Reported by: James Van Vleet

ASTERISK-24381 #close
Reported by: Matt Jordan
........

Merged revisions 425868 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 425879 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@425881 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Matthew Jordan
2014-10-17 13:35:44 +00:00
parent 0d0e38a0e1
commit 8f58592252
3 changed files with 58 additions and 172 deletions
Download Patch File Download Diff File Expand all files Collapse all files

194
res/res_pjsip_session.c
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@@ -186,160 +186,10 @@ void ast_sip_session_unregister_sdp_handler(struct ast_sip_session_sdp_handler *
ao2_callback_data(sdp_handlers, OBJ_KEY | OBJ_UNLINK | OBJ_NODATA, remove_handler, (void *)stream_type, handler);
}
static int validate_port_hash(const void *obj, int flags)
{
const int *port = obj;
return *port;
}
static int validate_port_cmp(void *obj, void *arg, int flags)
{
int *port1 = obj;
int *port2 = arg;
return *port1 == *port2 ? CMP_MATCH | CMP_STOP : 0;
}
struct bundle_assoc {
int port;
char tag[1];
};
static int bundle_assoc_hash(const void *obj, int flags)
{
const struct bundle_assoc *assoc = obj;
const char *tag = flags & OBJ_KEY ? obj : assoc->tag;
return ast_str_hash(tag);
}
static int bundle_assoc_cmp(void *obj, void *arg, int flags)
{
struct bundle_assoc *assoc1 = obj;
struct bundle_assoc *assoc2 = arg;
const char *tag2 = flags & OBJ_KEY ? arg : assoc2->tag;
return strcmp(assoc1->tag, tag2) ? 0 : CMP_MATCH | CMP_STOP;
}
/* return must be ast_freed */
static pjmedia_sdp_attr *media_get_mid(pjmedia_sdp_media *media)
{
pjmedia_sdp_attr *attr = pjmedia_sdp_media_find_attr2(media, "mid", NULL);
if (!attr) {
return NULL;
}
return attr;
}
static int get_bundle_port(const pjmedia_sdp_session *sdp, const char *mid)
{
int i;
for (i = 0; i < sdp->media_count; ++i) {
pjmedia_sdp_attr *mid_attr = media_get_mid(sdp->media[i]);
if (mid_attr && !pj_strcmp2(&mid_attr->value, mid)) {
return sdp->media[i]->desc.port;
}
}
return -1;
}
static int validate_incoming_sdp(const pjmedia_sdp_session *sdp)
{
int i;
RAII_VAR(struct ao2_container *, portlist, ao2_container_alloc(5, validate_port_hash, validate_port_cmp), ao2_cleanup);
RAII_VAR(struct ao2_container *, bundle_assoc_list, ao2_container_alloc(5, bundle_assoc_hash, bundle_assoc_cmp), ao2_cleanup);
/* check for bundles (for websocket RTP multiplexing, there can be more than one) */
for (i = 0; i < sdp->attr_count; ++i) {
char *bundle_list;
int bundle_port = 0;
if (pj_stricmp2(&sdp->attr[i]->name, "group")) {
continue;
}
/* check to see if this group is a bundle */
if (7 >= sdp->attr[i]->value.slen || pj_strnicmp2(&sdp->attr[i]->value, "bundle ", 7)) {
continue;
}
bundle_list = ast_alloca(sdp->attr[i]->value.slen - 6);
strncpy(bundle_list, sdp->attr[i]->value.ptr + 7, sdp->attr[i]->value.slen - 7);
bundle_list[sdp->attr[i]->value.slen - 7] = '\0';
while (bundle_list) {
char *item;
RAII_VAR(struct bundle_assoc *, assoc, NULL, ao2_cleanup);
item = strsep(&bundle_list, " ,");
if (!bundle_port) {
RAII_VAR(int *, port, ao2_alloc(sizeof(int), NULL), ao2_cleanup);
RAII_VAR(int *, port_match, NULL, ao2_cleanup);
bundle_port = get_bundle_port(sdp, item);
if (bundle_port < 0) {
return -1;
}
port_match = ao2_find(portlist, &bundle_port, OBJ_KEY);
if (port_match) {
/* bundle port aready consumed by a different bundle */
return -1;
}
*port = bundle_port;
ao2_link(portlist, port);
}
assoc = ao2_alloc(sizeof(*assoc) + strlen(item), NULL);
if (!assoc) {
return -1;
}
/* safe use of strcpy */
strcpy(assoc->tag, item);
assoc->port = bundle_port;
ao2_link(bundle_assoc_list, assoc);
}
}
/* validate all streams */
for (i = 0; i < sdp->media_count; ++i) {
RAII_VAR(int *, port, ao2_alloc(sizeof(int), NULL), ao2_cleanup);
RAII_VAR(int *, port_match, NULL, ao2_cleanup);
*port = sdp->media[i]->desc.port;
port_match = ao2_find(portlist, port, OBJ_KEY);
if (port_match) {
RAII_VAR(struct bundle_assoc *, assoc, NULL, ao2_cleanup);
pjmedia_sdp_attr *mid = media_get_mid(sdp->media[i]);
char *mid_val;
if (!mid) {
/* not part of a bundle */
return -1;
}
mid_val = ast_alloca(mid->value.slen + 1);
strncpy(mid_val, mid->value.ptr, mid->value.slen);
mid_val[mid->value.slen] = '\0';
assoc = ao2_find(bundle_assoc_list, mid_val, OBJ_KEY);
if (!assoc || assoc->port != *port) {
/* This port already exists elsewhere in the SDP
* and is not an appropriate bundle port, fail
* catastrophically */
return -1;
}
}
ao2_link(portlist, port);
}
return 0;
}
static int handle_incoming_sdp(struct ast_sip_session *session, const pjmedia_sdp_session *sdp)
{
int i;
if (validate_incoming_sdp(sdp)) {
return -1;
}
int handled = 0;
for (i = 0; i < sdp->media_count; ++i) {
/* See if there are registered handlers for this media stream type */
@@ -361,14 +211,22 @@ static int handle_incoming_sdp(struct ast_sip_session *session, const pjmedia_sd
if (session_media->handler) {
handler = session_media->handler;
ast_debug(1, "Negotiating incoming SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
session_media->handler->id);
res = handler->negotiate_incoming_sdp_stream(session, session_media, sdp,
sdp->media[i]);
if (res <= 0) {
/* Catastrophic failure or ignored by assigned handler. Abort! */
if (res < 0) {
/* Catastrophic failure. Abort! */
return -1;
} else if (res > 0) {
ast_debug(1, "Media stream '%s' handled by %s\n",
session_media->stream_type,
session_media->handler->id);
/* Handled by this handler. Move to the next stream */
handled = 1;
continue;
}
/* Handled by this handler. Move to the next stream */
continue;
}
handler_list = ao2_find(sdp_handlers, media, OBJ_KEY);
@@ -377,6 +235,9 @@ static int handle_incoming_sdp(struct ast_sip_session *session, const pjmedia_sd
continue;
}
AST_LIST_TRAVERSE(&handler_list->list, handler, next) {
ast_debug(1, "Negotiating incoming SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
handler->id);
res = handler->negotiate_incoming_sdp_stream(session, session_media, sdp,
sdp->media[i]);
if (res < 0) {
@@ -384,12 +245,19 @@ static int handle_incoming_sdp(struct ast_sip_session *session, const pjmedia_sd
return -1;
}
if (res > 0) {
ast_debug(1, "Media stream '%s' handled by %s\n",
session_media->stream_type,
handler->id);
/* Handled by this handler. Move to the next stream */
session_media->handler = handler;
handled = 1;
break;
}
}
}
if (!handled) {
return -1;
}
return 0;
}
@@ -429,9 +297,15 @@ static int handle_negotiated_sdp_session_media(void *obj, void *arg, int flags)
handler = session_media->handler;
if (handler) {
ast_debug(1, "Applying negotiated SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
handler->id);
res = handler->apply_negotiated_sdp_stream(session, session_media, local,
local->media[i], remote, remote->media[i]);
if (res >= 0) {
ast_debug(1, "Applied negotiated SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
handler->id);
return CMP_MATCH;
}
return 0;
@@ -443,6 +317,9 @@ static int handle_negotiated_sdp_session_media(void *obj, void *arg, int flags)
continue;
}
AST_LIST_TRAVERSE(&handler_list->list, handler, next) {
ast_debug(1, "Applying negotiated SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
handler->id);
res = handler->apply_negotiated_sdp_stream(session, session_media, local,
local->media[i], remote, remote->media[i]);
if (res < 0) {
@@ -450,6 +327,9 @@ static int handle_negotiated_sdp_session_media(void *obj, void *arg, int flags)
return 0;
}
if (res > 0) {
ast_debug(1, "Applied negotiated SDP media stream '%s' using %s SDP handler\n",
session_media->stream_type,
handler->id);
/* Handled by this handler. Move to the next stream */
session_media->handler = handler;
return CMP_MATCH;
@@ -827,10 +707,6 @@ static int sdp_requires_deferral(struct ast_sip_session *session, const pjmedia_
{
int i;
if (validate_incoming_sdp(sdp)) {
return 0;
}
for (i = 0; i < sdp->media_count; ++i) {
/* See if there are registered handlers for this media stream type */
char media[20];