mgcp: Test and implement re-transmission handling

MGCP is used over UDP and a response might be lost. The MGCP RFC
asks for keeping a list of responses and then using the previous
response to answer a duplicate request. I tried to conserve memory
and just wanted to remember the last transaction identifier and
result-code and re-generate the result from that. This made the
code look bad and this is why the entire response will now be stored.
It sadly increases the memory usage but can not be avoided at this
time.

Remove the msg->l3h pointer for the RQNT callback as strtok has
modified the content of it.

2 files changed, 64 insertions, 5 deletions

diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index f0b58ef02..4dfd2abe3 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -103,11 +103,12 @@
 		 "X: B244F267488\r\n"			\
 		 "S: D/9\r\n"
 
-#define RQNT2	 "RQNT 186908780 1@mgw MGCP 1.0\r\n"	\
+#define RQNT2	 "RQNT 186908781 1@mgw MGCP 1.0\r\n"	\
 		 "X: ADD4F26746F\r\n"			\
 		 "R: D/[0-9#*](N), G/ft, fxr/t38\r\n"
 
-#define RQNT_RET "200 186908780 OK\r\n"
+#define RQNT1_RET "200 186908780 OK\r\n"
+#define RQNT2_RET "200 186908781 OK\r\n"
 
 struct mgcp_test {
 	const char *name;
@@ -129,8 +130,16 @@ static const struct mgcp_test tests[] = {
 	{ "SHORT2", SHORT2, SHORT2_RET },
 	{ "SHORT3", SHORT3, SHORT2_RET },
 	{ "SHORT4", SHORT4, SHORT2_RET },
-	{ "RQNT1", RQNT, RQNT_RET },
-	{ "RQNT2", RQNT2, RQNT_RET },
+	{ "RQNT1", RQNT, RQNT1_RET },
+	{ "RQNT2", RQNT2, RQNT2_RET },
+	{ "DLCX", DLCX, DLCX_RET },
+};
+
+static const struct mgcp_test retransmit[] = {
+	{ "CRCX", CRCX, CRCX_RET },
+	{ "RQNT1", RQNT, RQNT1_RET },
+	{ "RQNT2", RQNT2, RQNT2_RET },
+	{ "MDCX3", MDCX3, MDCX3_RET },
 	{ "DLCX", DLCX, DLCX_RET },
 };
 
@@ -177,7 +186,46 @@ static void test_messages(void)
 	talloc_free(cfg);
 }
 
-static int rqnt_cb(struct mgcp_endpoint *endp, char _tone, const char *data)
+static void test_retransmission(void)
+{
+	struct mgcp_config *cfg;
+	int i;
+
+	cfg = mgcp_config_alloc();
+
+	cfg->trunk.number_endpoints = 64;
+	mgcp_endpoints_allocate(&cfg->trunk);
+
+	mgcp_endpoints_allocate(mgcp_trunk_alloc(cfg, 1));
+
+	for (i = 0; i < ARRAY_SIZE(retransmit); i++) {
+		const struct mgcp_test *t = &retransmit[i];
+		struct msgb *inp;
+		struct msgb *msg;
+
+		printf("Testing %s\n", t->name);
+
+		inp = create_msg(t->req);
+		msg = mgcp_handle_message(cfg, inp);
+		msgb_free(inp);
+		if (strcmp((char *) msg->data, t->exp_resp) != 0)
+			printf("%s failed '%s'\n", t->name, (char *) msg->data);
+		msgb_free(msg);
+
+		/* Retransmit... */
+		printf("Re-transmitting %s\n", t->name);
+		inp = create_msg(t->req);
+		msg = mgcp_handle_message(cfg, inp);
+		msgb_free(inp);
+		if (strcmp((char *) msg->data, t->exp_resp) != 0)
+			printf("%s failed '%s'\n", t->name, (char *) msg->data);
+		msgb_free(msg);
+	}
+
+	talloc_free(cfg);
+}
+
+static int rqnt_cb(struct mgcp_endpoint *endp, char _tone)
 {
 	ptrdiff_t tone = _tone;
 	endp->cfg->data = (void *) tone;
@@ -280,6 +328,7 @@ int main(int argc, char **argv)
 	osmo_init_logging(&log_info);
 
 	test_messages();
+	test_retransmission();
 	test_packet_loss_calc();
 	test_rqnt_cb();
 
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index dc0b3225a..224bba8d7 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -14,5 +14,15 @@ Testing SHORT4
 Testing RQNT1
 Testing RQNT2
 Testing DLCX
+Testing CRCX
+Re-transmitting CRCX
+Testing RQNT1
+Re-transmitting RQNT1
+Testing RQNT2
+Re-transmitting RQNT2
+Testing MDCX3
+Re-transmitting MDCX3
+Testing DLCX
+Re-transmitting DLCX
 Testing packet loss calculation.
 Done