gtphub: track tunnels explicitly.

So far, gtphub worked perfectly by only tracking single TEIs ... for probably
most uses. But a Ctrl plane tunnel may have expired despite a still active
corresponding User plane tunnel. The User plane would continue to work
indefinitely, but if any Ctrl messages followed after more than six hours of
Ctrl silence, they would have been dropped due to an expired TEI mapping.

We want to
- combine expiry of a user TEI with its ctrl TEI. (done in this patch)
- upon delete PDP context, remove both user and ctrl TEI mappings. (future)
- when a peer indicates a restart counter bump, invalidate its tunnels.
  (future)

To facilitate these, track tunnels, complete with both SGSN's and GGSN's
address, original and replaced TEIs, all for both user and ctrl plane, in a
single struct. A single expiry entry handles the entire tunnel, instead of
previously four separate expiries for each endpoint identifier.

Add the concept of a "side", being either GGSN or SGSN, to index tunnel
endpoint structs, and so on.

Track the originating side in the gtp_packet_desc.

Add header_tei_rx: set_tei() overwrites header_tei, but the originally received
header TEI is still needed to match a Create PDP Context Response up with its
Request (and for logging).

Adjust the test suite to expect tunnel listing strings instead of TEI mappings,
with a bonus of making it a lot easier to grok, and including the IP addresses.

Add regression test for refreshing tunnel expiry upon use.

Note: the current implementation is as slow as can possibly be, iterating all
the tunnels all the time. Optimizations are kept for a future commit, on
purpose.

BTW, the sequence number mapping/unmapping structures remain unchanged.

Sponsored-by: On-Waves ehi

1 files changed, 63 insertions, 10 deletions

diff --git a/openbsc/tests/gtphub/gtphub_test.c b/openbsc/tests/gtphub/gtphub_test.c
index 2dc61eb8e..418100261 100644
--- a/openbsc/tests/gtphub/gtphub_test.c
+++ b/openbsc/tests/gtphub/gtphub_test.c
@@ -49,7 +49,7 @@
 
 /* Convenience makro, note: only within this C file. */
 #define LOG(label) \
-	{ LOGP(DGTPHUB, LOGL_NOTICE, "\n\n" label "\n"); \
+	{ fprintf(stderr, "\n" label "\n"); \
 	  printf(label "\n"); }
 
 void gtphub_init(struct gtphub *hub);
@@ -597,7 +597,7 @@ static int setup_test_hub()
 	now = 345;
 	LVL2_ASSERT(send_from_sgsn("192.168.42.23", 423));
 	LVL2_ASSERT(resolve_to_ggsn("192.168.43.34", 2123));
-	LVL2_ASSERT(send_from_ggsn("192.168.43.34", 321));
+	LVL2_ASSERT(send_from_ggsn("192.168.43.34", 434));
 	LVL2_ASSERT(resolve_to_sgsn("192.168.42.23", 2123));
 
 #define GGSNS_CTRL_FD 1
@@ -615,7 +615,7 @@ static int setup_test_hub()
 static int clear_test_hub()
 {
 	/* expire all */
-	gtphub_gc(hub, now + (60 * GTPH_TEI_MAPPING_EXPIRY_MINUTES) + 1);
+	gtphub_gc(hub, now + (60 * GTPH_EXPIRE_SLOWLY_MINUTES) + 1);
 
 	int plane_idx;
 	plane_idx = GTPH_PLANE_CTRL;
@@ -629,6 +629,32 @@ static int clear_test_hub()
 	return 1;
 }
 
+static int tunnels_are(const char *expect)
+{
+	static char buf[4096];
+	char *pos = buf;
+	size_t len = sizeof(buf);
+	struct gtphub_tunnel *t;
+	llist_for_each_entry(t, &hub->tunnels, entry) {
+		size_t wrote = snprintf(pos, len, "%s @%d\n",
+					gtphub_tunnel_str(t),
+					(int)t->expiry_entry.expiry);
+		LVL2_ASSERT(wrote < len);
+		pos += wrote;
+		len -= wrote;
+	}
+	*pos = '\0';
+
+	if (strncmp(buf, expect, sizeof(buf)) != 0) {
+		fprintf(stderr, "FAILURE: tunnels_are() mismatches expected value:\n"
+		       "EXPECTED:\n%s\n"
+		       "IS:\n%s\n",
+		       expect, buf);
+		LVL2_ASSERT("tunnels do not match expected listing.");
+		return 0;
+	}
+	return 1;
+}
 
 static void test_echo(void)
 {
@@ -893,6 +919,11 @@ static int create_pdp_ctx()
 				    gtp_req_to_ggsn));
 	LVL2_ASSERT(was_resolved_for("240010123456789", "internet"));
 
+	LVL2_ASSERT(tunnels_are(
+		"192.168.42.23 (TEI C 321=1 / U 123=1)"
+		" <-> 192.168.43.34 / (uninitialized) (TEI C 0=0 / U 0=0)"
+		" @21945\n"));
+
 	const char *gtp_resp_from_ggsn =
 		MSG_PDP_CTX_RSP("004e",
 				"00000001", /* destination TEI (sent in req above) */
@@ -947,11 +978,10 @@ static void test_create_pdp_ctx(void)
 	 * 0x00000765 == 1893 (TEI from GGSN Ctrl)
 	 * 0x00000567 == 1383 (TEI from GGSN User)
 	 * Mapped TEIs should be 1 and 2. */
-	OSMO_ASSERT(nr_map_is(&hub->tei_map[GTPH_PLANE_CTRL],
-			      "(801->1@21945), (1893->2@21945), "));
-	OSMO_ASSERT(nr_map_is(&hub->tei_map[GTPH_PLANE_USER],
-			      "(291->1@21945), (1383->2@21945), "));
-
+	OSMO_ASSERT(tunnels_are(
+		"192.168.42.23 (TEI C 321=1 / U 123=1)"
+		" <-> 192.168.43.34 (TEI C 765=2 / U 567=2)"
+		" @21945\n"));
 	OSMO_ASSERT(clear_test_hub());
 }
 
@@ -963,11 +993,20 @@ static void test_user_data(void)
 
 	OSMO_ASSERT(create_pdp_ctx());
 
+	/* now == 345; now + (6 * 60 * 60) == 21600 + 345 == 21945. */
+	OSMO_ASSERT(tunnels_are(
+		"192.168.42.23 (TEI C 321=1 / U 123=1)"
+		" <-> 192.168.43.34 (TEI C 765=2 / U 567=2)"
+		" @21945\n"));
+
 	LOG("- user data starts");
-	/* Now expect default port numbers for User. */
+	/* Now expect default port numbers for User plane. */
 	resolve_to_ggsn("192.168.43.34", 2152);
 	resolve_to_sgsn("192.168.42.23", 2152);
 
+	/* 10 minutes later */
+	now += 600;
+
 	const char *u_from_ggsn =
 		"32" 	/* 0b001'1 0010: version 1, protocol GTP, with seq nr */
 		"ff"	/* type 255: G-PDU */
@@ -999,6 +1038,13 @@ static void test_user_data(void)
 				    u_from_ggsn,
 				    u_to_sgsn));
 
+	/* Make sure the user plane messages have refreshed the TEI mapping
+	 * timeouts: 21945 + 600 == 22545. */
+	OSMO_ASSERT(tunnels_are(
+		"192.168.42.23 (TEI C 321=1 / U 123=1)"
+		" <-> 192.168.43.34 (TEI C 765=2 / U 567=2)"
+		" @22545\n"));
+
 	const char *u_from_sgsn =
 		"32" 	/* 0b001'1 0010: version 1, protocol GTP, with seq nr */
 		"ff"	/* type 255: G-PDU */
@@ -1028,6 +1074,13 @@ static void test_user_data(void)
 				    u_from_sgsn,
 				    u_to_ggsn));
 
+	/* Make sure the user plane messages have refreshed the TEI mapping
+	 * timeouts: 21945 + 600 == 22545. Both timeouts refreshed: */
+	OSMO_ASSERT(tunnels_are(
+		"192.168.42.23 (TEI C 321=1 / U 123=1)"
+		" <-> 192.168.43.34 (TEI C 765=2 / U 567=2)"
+		" @22545\n"));
+
 	OSMO_ASSERT(clear_test_hub());
 }
 
@@ -1037,7 +1090,7 @@ static struct log_info_cat gtphub_categories[] = {
 		.name = "DGTPHUB",
 		.description = "GTP Hub",
 		.color = "\033[1;33m",
-		.enabled = 1, .loglevel = LOGL_NOTICE,
+		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
 };