sip: fix TCP source port (#921)

* sip: fix TCP source port

The TCP source has at the `struct sip` has to be set before the TCP connection
is opened. This commit fixes an issue that was introduced with
5c709fc which postponed the call to the
`send_handler()` after the TCP connection is established.

* sipreg: remove unneeded check

include/re_sip.h

@@ -395,6 +395,8 @@ int  sip_dialog_update(struct sip_dialog *dlg, const struct sip_msg *msg);
 bool sip_dialog_rseq_valid(struct sip_dialog *dlg, const struct sip_msg *msg);
 const char *sip_dialog_callid(const struct sip_dialog *dlg);
 int  sip_dialog_set_callid(struct sip_dialog *dlg, const char *callid);
+void sip_dialog_set_srcport(struct sip_dialog *dlg, uint16_t srcport);
+uint16_t sip_dialog_srcport(struct sip_dialog *dlg);
 const char *sip_dialog_uri(const struct sip_dialog *dlg);
 uint32_t sip_dialog_lseq(const struct sip_dialog *dlg);
 enum sip_transp sip_dialog_tp(const struct sip_dialog *dlg);

src/sip/dialog.c

@@ -36,6 +36,7 @@ struct sip_dialog {
 	uint32_t rseq;
 	size_t cpos;
 	enum sip_transp tp;
+	uint32_t srcport;
 };
 
 
@@ -578,6 +579,37 @@ int sip_dialog_set_callid(struct sip_dialog *dlg, const char *callid)
 }
 
 
+/**
+ * Set TCP source port for a SIP Dialog
+ *
+ * @param dlg  SIP Dialog
+ * @param srcport The TCP source port to be used
+ */
+void sip_dialog_set_srcport(struct sip_dialog *dlg, uint16_t srcport)
+{
+	if (!dlg)
+		return;
+
+	dlg->srcport = srcport;
+}
+
+
+/**
+ * Get TCP source port for a SIP Dialog
+ *
+ * @param dlg  SIP Dialog
+ *
+ * @return TCP source port
+ */
+uint16_t sip_dialog_srcport(struct sip_dialog *dlg)
+{
+	if (!dlg)
+		return 0;
+
+	return dlg->srcport;
+}
+
+
 /**
  * Get the local sequence number from a SIP Dialog
  *

src/sip/request.c

@@ -43,6 +43,7 @@ struct sip_request {
 	bool canceled;
 	bool provrecv;
 	uint16_t port;
+	uint16_t srcport;
 };
 
 
@@ -224,6 +225,11 @@ static int request(struct sip_request *req, enum sip_transp tp,
 	if (!req->branch || !mb)
 		goto out;
 
+	if (req->srcport) {
+		struct sip_conncfg cfg = {.srcport = req->srcport};
+		err = sip_conncfg_set(req->sip, dst, &cfg);
+	}
+
 	if (!req->stateful) {
 		err = sip_send_conn(req->sip, NULL, tp, dst, mb,
 				    connect_handler, req);
@@ -940,6 +946,7 @@ int sip_drequestf(struct sip_request **reqp, struct sip *sip, bool stateful,
 		goto out;
 
 	req->reqp = reqp;
+	req->srcport = sip_dialog_srcport(dlg);
 	err = sip_request_send(req, sip, sip_dialog_route(dlg));
 
 out:

src/sipreg/reg.c

@@ -295,6 +295,7 @@ static int send_handler(enum sip_transp tp, struct sa *src,
 	int err;
 
 	(void)contp;
+	(void)dst;
 
 	reg->tp = tp;
 	if (reg->srcport && tp != SIP_TRANSP_UDP)
@@ -313,14 +314,6 @@ static int send_handler(enum sip_transp tp, struct sa *src,
 		err |= mbuf_printf(mb, ";reg-id=%d", reg->regid);
 
 	err |= mbuf_printf(mb, "\r\n");
-
-	if (reg->srcport) {
-		struct sip_conncfg cfg;
-		memset(&cfg, 0, sizeof(cfg));
-		cfg.srcport = reg->srcport;
-		err = sip_conncfg_set(reg->sip, dst, &cfg);
-	}
-
 	return err;
 }
 
@@ -618,10 +611,12 @@ int sipreg_set_fbregint(struct sipreg *reg, uint32_t fbregint)
  */
 void sipreg_set_srcport(struct sipreg *reg, uint16_t srcport)
 {
-	if (!reg)
+	if (!reg || !reg->dlg)
 		return;
 
 	reg->srcport = srcport;
+
+	sip_dialog_set_srcport(reg->dlg, srcport);
 }