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gbproxy: Send DETACH_ACC if the IMSI has not been acquired

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If IMSI acquisition is enabled and the gbproxy receives a Detach
request from the MS, it cannot pass it to the SGSN since the
acquisition has not yet been completed.

This patch implements the generation of a Detach Accept message and
for this case and updates the TLLI state accordingly.

Sponsored-by: On-Waves ehf
This commit is contained in:
Jacob Erlbeck
2014-09-12 12:12:31 +02:00
parent 948c07f490
commit 2a5096dfc6
2 changed files with 64 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
openbsc/src/gprs/gb_proxy.c
View File

@@ -110,6 +110,17 @@ static void gprs_put_identity_req(struct msgb *msg, uint8_t id_type)
gh->data[0] = id_type;
}
/* Transmit Chapter 9.4.6.2 Detach Accept (mobile originated detach) */
static void gprs_put_mo_detach_acc(struct msgb *msg)
{
struct gsm48_hdr *gh;
gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh) + 1);
gh->proto_discr = GSM48_PDISC_MM_GPRS;
gh->msg_type = GSM48_MT_GMM_DETACH_ACK;
gh->data[0] = 0; /* no force to standby */
}
static void gprs_push_llc_ui(struct msgb *msg,
int is_uplink, unsigned sapi, unsigned nu)
{
@@ -348,6 +359,21 @@ static void gbproxy_acquire_imsi(struct gbproxy_peer *peer,
msgb_free(idreq_msg);
}
static void gbproxy_tx_detach_acc(struct gbproxy_peer *peer,
struct gbproxy_tlli_info* tlli_info,
uint16_t bvci)
{
struct msgb *detacc_msg;
/* Send DETACH ACC */
detacc_msg = gsm48_msgb_alloc();
gprs_put_mo_detach_acc(detacc_msg);
gprs_push_llc_ui(detacc_msg, 0, GPRS_SAPI_GMM,
(tlli_info->imsi_acq_retries + 256) % 512);
gprs_push_bssgp_dl_unitdata(detacc_msg, tlli_info->tlli.current);
gbprox_relay2peer(detacc_msg, peer, bvci);
msgb_free(detacc_msg);
}
/* Return != 0 iff msg still needs to be processed */
static int gbproxy_imsi_acquisition(struct gbproxy_peer *peer,
@@ -365,15 +391,37 @@ static int gbproxy_imsi_acquisition(struct gbproxy_peer *peer,
if (!tlli_info->imsi_acq_pending && tlli_info->imsi_len > 0)
return 1;
if (parse_ctx->g48_hdr &&
parse_ctx->g48_hdr->msg_type == GSM48_MT_GMM_ATTACH_REQ)
if (parse_ctx->g48_hdr)
switch (parse_ctx->g48_hdr->msg_type)
{
case GSM48_MT_GMM_ATTACH_REQ:
if (gbproxy_restart_imsi_acquisition(tlli_info)) {
LOGP(DLLC, LOGL_INFO,
"NSEI=%d(BSS) IMSI acquisition was in progress "
"when receiving an ATTACH_REQ.\n",
msgb_nsei(msg));
}
break;
case GSM48_MT_GMM_DETACH_REQ:
/* Nothing has been sent to the SGSN yet */
if (tlli_info->imsi_acq_pending) {
LOGP(DLLC, LOGL_INFO,
"NSEI=%d(BSS) IMSI acquisition was in progress "
"when receiving a DETACH_REQ.\n",
msgb_nsei(msg));
}
if (!parse_ctx->invalidate_tlli) {
LOGP(DLLC, LOGL_INFO,
"NSEI=%d(BSS) IMSI not yet acquired, "
"faking a DETACH_ACC.\n",
msgb_nsei(msg));
gbproxy_tx_detach_acc(peer, tlli_info, msgb_bvci(msg));
parse_ctx->invalidate_tlli = 1;
}
gbproxy_reset_imsi_acquisition(tlli_info);
gbproxy_update_tlli_state_after(peer, tlli_info, now,
parse_ctx);
return 0;
}
if (tlli_info->imsi_acq_pending && tlli_info->imsi_len > 0) {

15
openbsc/tests/gbproxy/gbproxy_test.ok
View File

@@ -3076,6 +3076,10 @@ PROCESSING DETACH REQ from 0x01020304:1111
CALLBACK, event 0, msg length 44, bvci 0x1002
00 00 10 02 01 80 00 de ad 00 00 04 08 88 11 22 33 40 50 60 12 34 00 80 0e 00 15 01 c0 1d 08 05 01 18 05 f4 ef e2 b7 00 19 03 b9 97 cb aa cc a3
NS UNITDATA MESSAGE to BSS, BVCI 0x1002, msg length 24 (gprs_ns_sendmsg)
MESSAGE to BSS at 0x01020304:1111, msg length 28
00 00 10 02 00 80 00 de ad 00 50 20 16 82 02 58 0e 00 09 41 c4 05 08 06 00 29 4a 68
result (DETACH REQ) = 0
Peers:
@@ -3086,9 +3090,7 @@ Peers:
TLLI patched (SGSN): 9
P-TMSI patched (SGSN): 1
Attach Request count : 3
TLLI cache size : 1
TLLI-Cache: 1
TLLI 8000dead -> 7eb52dfb, IMSI (none), AGE 0, STORED 2, IMSI acquisition in progress
TLLI-Cache: 0
PROCESSING DETACH REQ (unknown TLLI) from 0x01020304:1111
00 00 10 02 01 80 00 be ef 00 00 04 08 88 11 22 33 40 50 60 12 34 00 80 0e 00 15 01 c0 21 08 05 01 18 05 f4 ef e2 b7 00 19 03 b9 97 cb ca 4d 70
@@ -3097,7 +3099,7 @@ CALLBACK, event 0, msg length 44, bvci 0x1002
NS UNITDATA MESSAGE to BSS, BVCI 0x1002, msg length 24 (gprs_ns_sendmsg)
MESSAGE to BSS at 0x01020304:1111, msg length 28
00 00 10 02 00 80 00 be ef 00 50 20 16 82 02 58 0e 00 09 41 c4 01 08 15 01 b7 f8 36
00 00 10 02 00 80 00 be ef 00 50 20 16 82 02 58 0e 00 09 41 c4 01 08 06 00 11 f5 c0
result (DETACH REQ (unknown TLLI)) = 0
@@ -3109,10 +3111,7 @@ Peers:
TLLI patched (SGSN): 9
P-TMSI patched (SGSN): 1
Attach Request count : 3
TLLI cache size : 2
TLLI-Cache: 2
TLLI 8000beef -> 7e23ef54, IMSI (none), AGE 0, STORED 1, IMSI acquisition in progress
TLLI 8000dead -> 7eb52dfb, IMSI (none), AGE 0, STORED 2, IMSI acquisition in progress
TLLI-Cache: 0
Gbproxy global:
Invalid Routing Area Identifier : 1
BSSGP protocol error (SGSN): 1