gprs: Add APN patch support for LLC/GSM messages

Patch the APN in every 'Activate PDP Context Request' message to the
value given by the 'core-access-point-name' command. If the command is
given without an APN, the whole APN IE will be removed. If the
command is being prefixed by a 'no', the APN IE remains unmodified.

The patch mode 'llc-gsm' is added to selectively enable the patching
of LLC session management messages. This is enabled implicitely by
the patch mode 'llc'.

Note that the patch mode should not be set to a value not enabling
the patching of LLC GSM messages ('llc-gsm', 'llc', and 'default' are
sufficient to patch 'Activate PDP Context Request' messages).

Ticket: OW#1192
Sponsored-by: On-Waves ehf

2 files changed, 14 insertions, 9 deletions

diff --git a/openbsc/tests/gbproxy/gbproxy_test.c b/openbsc/tests/gbproxy/gbproxy_test.c
index e93c354f6..33b0ac544 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.c
+++ b/openbsc/tests/gbproxy/gbproxy_test.c
@@ -812,6 +812,8 @@ static void test_gbproxy_ra_patching()
 	gbcfg.nsip_sgsn_nsei = SGSN_NSEI;
 	gbcfg.core_mcc = 123;
 	gbcfg.core_mnc = 456;
+	gbcfg.core_apn = talloc_zero_size(NULL, 100);
+	gbcfg.core_apn_size = gbprox_str_to_apn(gbcfg.core_apn, "foo.bar", 100);
 
 	configure_sgsn_peer(&sgsn_peer);
 	configure_bss_peers(bss_peer, ARRAY_SIZE(bss_peer));
@@ -856,7 +858,8 @@ static void test_gbproxy_ra_patching()
 			 &bss_peer[0], 0x1002,
 			 bssgp_act_pdp_ctx_req, sizeof(bssgp_act_pdp_ctx_req));
 
-	/* TODO: Re-configure to test APN IE removal */
+	gbcfg.core_apn[0] = 0;
+	gbcfg.core_apn_size = 0;
 
 	/* Remove APN */
 	send_ns_unitdata(nsi, "ACT PDP CTX REQ (REMOVE APN)",
diff --git a/openbsc/tests/gbproxy/gbproxy_test.ok b/openbsc/tests/gbproxy/gbproxy_test.ok
index 64ed996dc..e73b25401 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.ok
+++ b/openbsc/tests/gbproxy/gbproxy_test.ok
@@ -1617,11 +1617,11 @@ PROCESSING ACT PDP CTX REQ (REPLACE APN) from 0x01020304:1111
 CALLBACK, event 0, msg length 76, bvci 0x1002
 00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 11 22 33 40 50 60 75 30 00 80 0e 00 35 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 03 02 61 62 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 5a ff 02 
 
-NS UNITDATA MESSAGE to SGSN, BVCI 0x1002, msg length 76 (gprs_ns_sendmsg)
-MESSAGE to SGSN at 0x05060708:32000, msg length 80
-00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 21 63 54 40 50 60 75 30 00 80 0e 00 35 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 03 02 61 62 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 5a ff 02 
+NS UNITDATA MESSAGE to SGSN, BVCI 0x1002, msg length 81 (gprs_ns_sendmsg)
+MESSAGE to SGSN at 0x05060708:32000, msg length 85
+00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 21 63 54 40 50 60 75 30 00 80 0e 00 3a 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 08 03 66 6f 6f 03 62 61 72 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 24 9d 75 
 
-result (ACT PDP CTX REQ (REPLACE APN)) = 80
+result (ACT PDP CTX REQ (REPLACE APN)) = 85
 
 PROCESSING ACT PDP CTX REQ (REMOVE APN) from 0x01020304:1111
 00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 11 22 33 40 50 60 75 30 00 80 0e 00 35 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 03 02 61 62 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 5a ff 02 
@@ -1629,15 +1629,16 @@ PROCESSING ACT PDP CTX REQ (REMOVE APN) from 0x01020304:1111
 CALLBACK, event 0, msg length 76, bvci 0x1002
 00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 11 22 33 40 50 60 75 30 00 80 0e 00 35 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 03 02 61 62 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 5a ff 02 
 
-NS UNITDATA MESSAGE to SGSN, BVCI 0x1002, msg length 76 (gprs_ns_sendmsg)
-MESSAGE to SGSN at 0x05060708:32000, msg length 80
-00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 21 63 54 40 50 60 75 30 00 80 0e 00 35 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 28 03 02 61 62 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 5a ff 02 
+NS UNITDATA MESSAGE to SGSN, BVCI 0x1002, msg length 71 (gprs_ns_sendmsg)
+MESSAGE to SGSN at 0x05060708:32000, msg length 75
+00 00 10 02 01 ef e2 b7 00 00 00 04 08 88 21 63 54 40 50 60 75 30 00 80 0e 00 30 01 c0 0d 0a 41 05 03 0c 00 00 1f 10 00 00 00 00 00 00 00 00 02 01 21 27 14 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 85 fa 60 
 
-result (ACT PDP CTX REQ (REMOVE APN)) = 80
+result (ACT PDP CTX REQ (REMOVE APN)) = 75
 
 Gbproxy global:
     RAID patched              (BSS ): 8
     RAID patched              (SGSN): 3
+    APN patched                     : 2
 Peers:
   NSEI 4096, BVCI 4098, not blocked, RAI 112-332-16464-96
 --- Bad cases ---
@@ -1667,6 +1668,7 @@ Gbproxy global:
     Invalid Routing Area Identifier : 1
     RAID patched              (BSS ): 8
     RAID patched              (SGSN): 4
+    APN patched                     : 2
 Peers:
   NSEI 4096, BVCI 4098, not blocked, RAI 112-332-16464-96
 ===== GbProxy test END