handle rport 'received' ip address in SDP

This needs commit 2654229cd9f05f8610b5789443caefc227fa0d9e (Use 'rport'
and 'received' parameters to adjust 'Contact' header according to RFC
3581) in libre.

include/baresip.h

@@ -939,6 +939,7 @@ unsigned ua_destroy(struct ua *ua);
 void ua_pub_gruu_set(struct ua *ua, const struct pl *pval);
 const char     *ua_cuser(const struct ua *ua);
 const char     *ua_local_cuser(const struct ua *ua);
+const struct sa *ua_raddr(const struct ua *ua);
 struct account *ua_account(const struct ua *ua);
 const char     *ua_outbound(const struct ua *ua);
 struct call    *ua_call(const struct ua *ua);

src/call.c

@@ -827,6 +827,7 @@ int call_alloc(struct call **callp, const struct config *cfg, struct list *lst,
 	struct call *call;
 	enum vidmode vidmode = prm ? prm->vidmode : VIDMODE_OFF;
 	int err = 0;
+	const struct sa *raddr;
 
 	if (!cfg || !local_uri || !acc || !ua || !prm)
 		return EINVAL;
@@ -873,8 +874,13 @@ int call_alloc(struct call **callp, const struct config *cfg, struct list *lst,
 	if (sip_msg_hdr_has_value(msg, SIP_HDR_SUPPORTED, "replaces"))
 		call->supported |= REPLACES;
 
+	/* if rport/received was set, use this. This is not 100% correct because
+	 * only the ip address ("received") will be used but not the port (which
+	 * would be the SIP port and not the RTP port anyway). */
+	raddr = ua_raddr(ua);
+
 	/* Init SDP info */
-	err = sdp_session_alloc(&call->sdp, &prm->laddr);
+	err = sdp_session_alloc(&call->sdp, sa_isset(raddr, SA_ADDR | SA_PORT) ? raddr : &prm->laddr);
 	if (err)
 		goto out;
 
@@ -2230,7 +2236,9 @@ int call_accept(struct call *call, struct sipsess_sock *sess_sock,
 
 	err = sipsess_accept(&call->sess, sess_sock, msg, 180, "Ringing",
 			     account_rel100_mode(call->acc),
-			     ua_cuser(call->ua), "application/sdp", NULL,
+			     ua_cuser(call->ua),
+			     ua_raddr(call->ua),
+			     "application/sdp", NULL,
 			     auth_handler, call->acc, true,
 			     sipsess_offer_handler, sipsess_answer_handler,
 			     sipsess_estab_handler, sipsess_info_handler,
@@ -2417,6 +2425,7 @@ static int send_invite(struct call *call)
 			      call->local_name,
 			      call->local_uri,
 			      ua_cuser(call->ua),
+			      ua_raddr(call->ua),
 			      routev[0] ? routev : NULL,
 			      routev[0] ? 1 : 0,
 			      "application/sdp",

src/core.h

@@ -246,6 +246,8 @@ const struct sa *reg_laddr(const struct reg *reg);
 const struct sa *reg_paddr(const struct reg *reg);
 void reg_set_custom_hdrs(struct reg *reg, const struct list *hdrs);
 
+const struct sa *reg_raddr(const struct reg *reg);
+
 /*
  * RTP Stats
  */

src/reg.c

@@ -426,8 +426,12 @@ const struct sa *reg_laddr(const struct reg *reg)
 	return sipreg_laddr(reg->sipreg);
 }
 
-
 const struct sa *reg_paddr(const struct reg *reg)
 {
 	return reg ? &reg->paddr : NULL;
 }
+
+const struct sa *reg_raddr(const struct reg *reg)
+{
+	return sipreg_raddr(reg->sipreg);
+}

src/ua.c

@@ -1860,6 +1860,23 @@ const char *ua_cuser(const struct ua *ua)
 	return ua->cuser;
 }
 
+const struct sa *ua_raddr(const struct ua *ua)
+{
+	struct le *le;
+	int i;
+
+	if (!ua)
+		return NULL;
+
+	for (le = ua->regl.head, i=0; le; le = le->next, i++) {
+		struct reg *reg = le->data;
+		const struct sa *raddr = reg_raddr(reg);
+		if (raddr)
+			return raddr;
+	}
+
+	return NULL;
+}
 
 /**
  * Get the local contact username