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osmo-sip-connector
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Handle SIP re-INVITEs 

SIP end points can send periodic re-INVITES. Previous to this commit,
the osmo-sip-connector would send a new call SETUP to the MSC for each
re-INVITE.

Add a function to find if we already handle this call based on the nua handle.
Use this function to detect and respond with an ACK to re-INVITES.

Add a function to extract the media mode from the SDP.
In the case the re-INVITE has a=sendonly (HOLD) respond with a=recvonly

In the case that the re-INVITE changes the media connection ip/port,
forward this to the MNCC side with an MNCC_RTP_CONNECT

Change-Id: I4083ed50d0cf1b302b80354fe0c2b73fc6e14fed
changes/94/14994/9
Keith Whyte 2019-07-30 15:58:55 +02:00
parent f9a2a414ef
commit 5f73c2033b
5 changed files with 157 additions and 5 deletions
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3
src/call.h
View File

@ -74,6 +74,9 @@ struct call_leg {
* A DTMF key was entered. Forward it.
*/
void (*dtmf)(struct call_leg *, int keypad);
void (*update_rtp)(struct call_leg *);
};
enum sip_cc_state {

19
src/mncc.c
View File

@ -198,6 +198,23 @@ static bool send_rtp_connect(struct mncc_call_leg *leg, struct call_leg *other)
return true;
}
static void update_rtp(struct call_leg *_leg) {
struct mncc_call_leg *leg;
LOGP(DMNCC, LOGL_DEBUG, "UPDATE RTP with LEG Type (%u)\n", _leg->type);
if (_leg->type == CALL_TYPE_MNCC) {
leg = (struct mncc_call_leg *) _leg;
struct call_leg *other = call_leg_other(&leg->base);
send_rtp_connect(leg, other);
} else {
leg = (struct mncc_call_leg *) call_leg_other(_leg);
send_rtp_connect(leg, _leg);
}
}
/* CONNECT call-back for MNCC call leg */
static void mncc_call_leg_connect(struct call_leg *_leg)
{
@ -482,6 +499,7 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
leg->base.connect_call = mncc_call_leg_connect;
leg->base.ring_call = mncc_call_leg_ring;
leg->base.release_call = mncc_call_leg_release;
leg->base.update_rtp = update_rtp;
leg->callref = data->callref;
leg->conn = conn;
leg->state = MNCC_CC_INITIAL;
@ -788,6 +806,7 @@ int mncc_create_remote_leg(struct mncc_connection *conn, struct call *call)
leg->base.ring_call = mncc_call_leg_ring;
leg->base.release_call = mncc_call_leg_release;
leg->base.call = call;
leg->base.update_rtp = update_rtp;
leg->callref = call->id;

39
src/sdp.c
View File

@ -32,6 +32,45 @@
#include <string.h>
/*
* Check if the media mode attribute exists in SDP, in this
* case update the passed pointer with the media mode
*/
bool sdp_get_sdp_mode(const sip_t *sip, sdp_mode_t *mode) {
const char *sdp_data;
sdp_parser_t *parser;
sdp_session_t *sdp;
if (!sip->sip_payload || !sip->sip_payload->pl_data) {
LOGP(DSIP, LOGL_ERROR, "No SDP file\n");
return false;
}
sdp_data = sip->sip_payload->pl_data;
parser = sdp_parse(NULL, sdp_data, strlen(sdp_data), sdp_f_mode_0000);
if (!parser) {
LOGP(DSIP, LOGL_ERROR, "Failed to parse SDP\n");
return false;
}
sdp = sdp_session(parser);
if (!sdp) {
LOGP(DSIP, LOGL_ERROR, "No sdp session\n");
sdp_parser_free(parser);
return false;
}
if (!sdp->sdp_media || !sdp->sdp_media->m_mode) {
sdp_parser_free(parser);
return sdp_sendrecv;
}
sdp_parser_free(parser);
*mode = sdp->sdp_media->m_mode;
return true;
}
/*
* We want to decide on the audio codec later but we need to see
* if it is even including some of the supported ones.

1
src/sdp.h
View File

@ -8,6 +8,7 @@
struct sip_call_leg;
struct call_leg;
bool sdp_get_sdp_mode(const sip_t *sip, sdp_mode_t *mode);
bool sdp_screen_sdp(const sip_t *sip);
bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec);

100
src/sip.c
View File

@ -41,6 +41,27 @@ static void sip_ring_call(struct call_leg *_leg);
static void sip_connect_call(struct call_leg *_leg);
static void sip_dtmf_call(struct call_leg *_leg, int keypad);
/* Find a SIP Call leg by given nua_handle */
static struct sip_call_leg *sip_find_leg(nua_handle_t *nh)
{
struct call *call;
llist_for_each_entry(call, &g_call_list, entry) {
if (call->initial && call->initial->type == CALL_TYPE_SIP) {
struct sip_call_leg *leg = (struct sip_call_leg *) call->initial;
if (leg->nua_handle == nh)
return leg;
}
if (call->remote && call->remote->type == CALL_TYPE_SIP) {
struct sip_call_leg *leg = (struct sip_call_leg *) call->remote;
if (leg->nua_handle == nh)
return leg;
}
}
return NULL;
}
static void call_progress(struct sip_call_leg *leg, const sip_t *sip, int status)
{
struct call_leg *other = call_leg_other(&leg->base);
@ -149,6 +170,57 @@ static void new_call(struct sip_agent *agent, nua_handle_t *nh,
talloc_strdup(leg, to));
}
static void sip_handle_reinvite(struct sip_call_leg *leg, nua_handle_t *nh, const sip_t *sip) {
char *sdp;
sdp_mode_t mode = sdp_sendrecv;
LOGP(DSIP, LOGL_NOTICE, "re-INVITE for call %s\n", sip->sip_call_id->i_id);
struct call_leg *other = call_leg_other(&leg->base);
if (!sdp_get_sdp_mode(sip, &mode)) {
/* re-INVITE with no SDP.
* We should respond with SDP reflecting current session
*/
sdp = sdp_create_file(leg, other, sdp_sendrecv);
nua_respond(nh, SIP_200_OK,
NUTAG_MEDIA_ENABLE(0),
SIPTAG_CONTENT_TYPE_STR("application/sdp"),
SIPTAG_PAYLOAD_STR(sdp),
TAG_END());
talloc_free(sdp);
return;
}
if (mode == sdp_sendonly) {
/* SIP side places call on HOLD */
sdp = sdp_create_file(leg, other, sdp_recvonly);
/* TODO: Tell core network to stop sending RTP ? */
} else {
/* SIP re-INVITE may want to change media, IP, port */
if (!sdp_extract_sdp(leg, sip, true)) {
LOGP(DSIP, LOGL_ERROR, "leg(%p) no audio, releasing\n", leg);
nua_respond(nh, SIP_406_NOT_ACCEPTABLE, TAG_END());
nua_handle_destroy(nh);
call_leg_release(&leg->base);
return;
}
if (other->update_rtp)
other->update_rtp(leg->base.call->remote);
sdp = sdp_create_file(leg, other, sdp_sendrecv);
}
LOGP(DSIP, LOGL_DEBUG, "Sending 200 response to re-INVITE for mode(%u)\n", mode);
nua_respond(nh, SIP_200_OK,
NUTAG_MEDIA_ENABLE(0),
SIPTAG_CONTENT_TYPE_STR("application/sdp"),
SIPTAG_PAYLOAD_STR(sdp),
TAG_END());
talloc_free(sdp);
return;
}
/* Sofia SIP definitions come with error code numbers and strings, this
* map allows us to reuse the existing definitions.
* The map is in priority order. The first matching entry found
@ -235,8 +307,13 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
if (status == 180 || status == 183)
call_progress(leg, sip, status);
else if (status == 200)
call_connect(leg, sip);
else if (status == 200) {
struct sip_call_leg *leg = sip_find_leg(nh);
if (leg)
nua_ack(leg->nua_handle, TAG_END());
else
call_connect(leg, sip);
}
else if (status >= 300) {
struct call_leg *other = call_leg_other(&leg->base);
@ -251,6 +328,14 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
other->release_call(other);
}
}
} else if (event == nua_i_ack) {
/* SDP comes back to us in 200 ACK after we
* respond to the re-INVITE query. */
if (sip->sip_payload && sip->sip_payload->pl_data) {
struct sip_call_leg *leg = sip_find_leg(nh);
if (leg)
sip_handle_reinvite(leg, nh, sip);
}
} else if (event == nua_r_bye || event == nua_r_cancel) {
/* our bye or hang up is answered */
struct sip_call_leg *leg = (struct sip_call_leg *) hmagic;
@ -270,10 +355,15 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
if (other)
other->release_call(other);
} else if (event == nua_i_invite) {
/* new incoming leg */
/* new incoming leg or re-INVITE */
if (status == 100)
new_call((struct sip_agent *) magic, nh, sip);
if (status == 100) {
struct sip_call_leg *leg = sip_find_leg(nh);
if (leg)
sip_handle_reinvite(leg, nh, sip);
else
new_call((struct sip_agent *) magic, nh, sip);
}
} else if (event == nua_i_cancel) {
struct sip_call_leg *leg;
struct call_leg *other;