keith has submitted this change and it was merged. ( 
https://gerrit.osmocom.org/c/osmo-sip-connector/+/14994 )

Change subject: Handle SIP re-INVITEs
......................................................................

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
---
M src/call.h
M src/mncc.c
M src/sdp.c
M src/sdp.h
M src/sip.c
5 files changed, 157 insertions(+), 5 deletions(-)

Approvals:
  Jenkins Builder: Verified
  keith: Looks good to me, approved



diff --git a/src/call.h b/src/call.h
index 65d1111..5076c01 100644
--- a/src/call.h
+++ b/src/call.h
@@ -74,6 +74,9 @@
         * A DTMF key was entered. Forward it.
         */
        void (*dtmf)(struct call_leg *, int keypad);
+
+       void (*update_rtp)(struct call_leg *);
+
 };

 enum sip_cc_state {
diff --git a/src/mncc.c b/src/mncc.c
index ab2bed6..6ee7670 100644
--- a/src/mncc.c
+++ b/src/mncc.c
@@ -198,6 +198,23 @@
        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 @@
        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 @@
        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;

diff --git a/src/sdp.c b/src/sdp.c
index 9bb55d4..52f7e25 100644
--- a/src/sdp.c
+++ b/src/sdp.c
@@ -33,6 +33,45 @@
 #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.
  */
diff --git a/src/sdp.h b/src/sdp.h
index 72ff6b7..8e4e314 100644
--- a/src/sdp.h
+++ b/src/sdp.h
@@ -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);

diff --git a/src/sip.c b/src/sip.c
index 21401c6..be0d24a 100644
--- a/src/sip.c
+++ b/src/sip.c
@@ -41,6 +41,27 @@
 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 @@
                        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 @@

                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 @@
                                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 @@
                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;

--
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Gerrit-Project: osmo-sip-connector
Gerrit-Branch: master
Gerrit-Change-Id: I4083ed50d0cf1b302b80354fe0c2b73fc6e14fed
Gerrit-Change-Number: 14994
Gerrit-PatchSet: 9
Gerrit-Owner: keith <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: keith <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: neels <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged

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