From a3d3f884cdfe5fc457428e66667839cd3ec67db1 Mon Sep 17 00:00:00 2001
From: Andreas Eversberg <jolly@eversberg.eu>
Date: Fri, 17 Sep 2021 15:42:33 +0200
Subject: Fix and cleanup of from/to uri generation for INVITE

If a remote peer registers to us, we can still use dialed number of an
outgoing call (INVITE) to replace the user of the to-line.

E.g. To: <user>@remote.host (if no dialed number is given)
     To: <number>@remote.host (if dialed number is given)
---
 src/sip/sip.c | 38 +++++++++++++++++++++++++-------------
 src/sip/sip.h |  1 +
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/src/sip/sip.c b/src/sip/sip.c
index d1f40c7..fe65fd7 100644
--- a/src/sip/sip.c
+++ b/src/sip/sip.c
@@ -472,6 +472,7 @@ static void setup_req(call_t *call, osmo_cc_msg_t *msg)
 	uint8_t type, plan, present, screen;
 	char callerid[256], dialing[256];
 	const char *sdp = sdp;
+	const char *user, *peer;
 	int rc;
 
 	if (!call->sip_ep->remote_peer || !call->sip_ep->remote_peer[0]) {
@@ -494,25 +495,36 @@ static void setup_req(call_t *call, osmo_cc_msg_t *msg)
 	rc = osmo_cc_get_ie_calling(msg, 0, &type, &plan, &present, &screen, callerid, sizeof(callerid));
 	if (rc < 0)
 		callerid[0] = '\0';
-	if (callerid[0] || call->sip_ep->local_user) {
-		sprintf(from, "sip:%s@%s", (call->sip_ep->local_user) ? : callerid, call->sip_ep->local_peer);
-		if (call->sip_ep->public_ip[0])
-			sprintf(contact, "sip:%s@%s", (call->sip_ep->local_user) ? : callerid, call->sip_ep->public_ip);
-	} else {
-		sprintf(from, "sip:%s", call->sip_ep->local_peer);
-		if (call->sip_ep->public_ip[0])
-			sprintf(contact, "sip:%s", call->sip_ep->public_ip);
-	}
+	user = NULL;
+	if (call->sip_ep->local_user)
+		user = call->sip_ep->local_user; // high prio
+	else if (callerid[0])
+		user = callerid; // low prio
+	peer = call->sip_ep->local_peer;
+	if (call->sip_ep->public_ip)
+		peer = call->sip_ep->public_ip;
+	if (user)
+		sprintf(from, "sip:%s@%s", user, peer);
+	else
+		sprintf(from, "sip:%s", peer);
 	PDEBUG(DSIP, DEBUG_DEBUG, " -> From = %s\n", from);
 
 	/* dialing information */
 	rc = osmo_cc_get_ie_called(msg, 0, &type, &plan, dialing, sizeof(dialing));
 	if (rc < 0)
 		dialing[0] = '\0';
-	if (dialing[0] || call->sip_ep->remote_user) {
-		sprintf(to, "sip:%s@%s", (call->sip_ep->remote_user) ? : dialing, call->sip_ep->remote_peer);
+	user = NULL;
+	if (call->sip_ep->remote_user)
+		user = call->sip_ep->remote_user; // high prio
+	else if (dialing[0])
+		user = dialing; // mid prio
+	else if (call->sip_ep->registered_user)
+		user = call->sip_ep->registered_user;
+	peer = call->sip_ep->remote_peer;
+	if (user) {
+		sprintf(to, "sip:%s@%s", user, peer);
 	} else
-		sprintf(to, "sip:%s", call->sip_ep->remote_peer);
+		sprintf(to, "sip:%s", peer);
 	PDEBUG(DSIP, DEBUG_DEBUG, " -> To = %s\n", to);
 
 	/* asserted id */
@@ -949,7 +961,7 @@ static void ep_i_register(sip_endpoint_t *sip_ep, int status, nua_t *nua, nua_ha
 	if (status == 200) {
 		strcpy(sip_ep->remote_contact_user, contact_user);
 		strcpy(sip_ep->remote_contact_peer, contact_peer);
-		sip_ep->remote_user = sip_ep->remote_contact_user;
+		sip_ep->registered_user = sip_ep->remote_contact_user;
 		sip_ep->remote_peer = sip_ep->remote_contact_peer;
 		sip_ep->register_nonce[0] = '\0';
 	}
diff --git a/src/sip/sip.h b/src/sip/sip.h
index da39cd3..753e466 100644
--- a/src/sip/sip.h
+++ b/src/sip/sip.h
@@ -47,6 +47,7 @@ typedef struct sip_endpoint {
 	const char	*local_user;
 	const char	*local_peer;
 	const char	*remote_user;
+	const char	*registered_user;
 	const char	*remote_peer;
 	const char	*asserted_id;
 	int		local_register;
-- 
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