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gbproxy: Change creation of tlli_info for SGSN originated messages 

Currently tlli_info are created for SGSN originated messages when
the SGSN TLLI cannot be found and P-TMSI patching is active. This
doesn't make much sense, since the BSS side TLLI is not known in this
case. Given that the SGSN is working properly, that can only happen
if either the tlli_info has expired or the gbproxy has been
restarted.

This patch disables the creation of a tlli_info in this case.

Note that these messages are passed unmodified to the MS so far.

Sponsored-by: On-Waves ehf
This commit is contained in:
Jacob Erlbeck 2014-09-05 10:22:27 +02:00
parent 52f070a099
commit 37fda77814
3 changed files with 73 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
openbsc/src/gprs/gb_proxy_patch.c
View File

@ -335,6 +335,15 @@ void gbproxy_patch_bssgp(struct msgb *msg, uint8_t *bssgp, size_t bssgp_len,
goto patch_error;
}
if (!tlli_info && parse_ctx->tlli_enc && parse_ctx->to_bss) {
/* Happens with unknown (not cached) TLLI coming from
* the SGSN */
/* TODO: What shall be done with the message in this case? */
err_ctr = GBPROX_PEER_CTR_TLLI_UNKNOWN;
err_info = "TLLI sent by the SGSN is unknown";
goto patch_error;
}
if (!tlli_info)
return;
@ -346,13 +355,6 @@ void gbproxy_patch_bssgp(struct msgb *msg, uint8_t *bssgp, size_t bssgp_len,
gbproxy_patch_tlli(parse_ctx->tlli_enc, peer, tlli,
parse_ctx->to_bss, "TLLI");
parse_ctx->tlli = tlli;
} else if (parse_ctx->to_bss) {
/* Happens with unknown (not cached) TLLI coming from
* the SGSN */
/* TODO: What shall be done with the message in this case? */
err_ctr = GBPROX_PEER_CTR_TLLI_UNKNOWN;
err_info = "TLLI sent by the SGSN is unknown";
goto patch_error;
} else {
/* Internal error */
err_ctr = GBPROX_PEER_CTR_PATCH_ERR;

81
openbsc/src/gprs/gb_proxy_tlli.c
View File

@ -440,8 +440,8 @@ struct gbproxy_tlli_info *gbproxy_update_tlli_state_dl(
if (parse_ctx->tlli_enc)
tlli_info = gbproxy_find_tlli_by_sgsn_tlli(peer, parse_ctx->tlli);
if (parse_ctx->tlli_enc && parse_ctx->new_ptmsi_enc) {
/* A new PTMSI has been signaled in the message,
if (parse_ctx->tlli_enc && parse_ctx->new_ptmsi_enc && tlli_info) {
/* A new P-TMSI has been signalled in the message,
* register new TLLI */
uint32_t new_sgsn_ptmsi;
uint32_t new_sgsn_tlli;
@ -461,46 +461,67 @@ struct gbproxy_tlli_info *gbproxy_update_tlli_state_dl(
LOGP(DGPRS, LOGL_INFO,
"Got new TLLI(PTMSI) %08x(%08x) from SGSN, using %08x(%08x)\n",
new_sgsn_tlli, new_sgsn_ptmsi, new_bss_tlli, new_bss_ptmsi);
if (tlli_info) {
gbproxy_reassign_tlli(&tlli_info->sgsn_tlli,
peer, new_sgsn_tlli);
gbproxy_reassign_tlli(&tlli_info->tlli,
peer, new_bss_tlli);
gbproxy_touch_tlli(peer, tlli_info, now);
} else {
tlli_info = gbproxy_tlli_info_alloc(peer);
LOGP(DGPRS, LOGL_INFO,
"Adding TLLI %08x to list (SGSN, new P-TMSI)\n",
new_sgsn_tlli);
gbproxy_attach_tlli_info(peer, now, tlli_info);
/* Setup TLLIs */
tlli_info->sgsn_tlli.current = new_sgsn_tlli;
}
gbproxy_reassign_tlli(&tlli_info->sgsn_tlli,
peer, new_sgsn_tlli);
gbproxy_reassign_tlli(&tlli_info->tlli,
peer, new_bss_tlli);
gbproxy_touch_tlli(peer, tlli_info, now);
/* Setup PTMSIs */
tlli_info->sgsn_tlli.ptmsi = new_sgsn_ptmsi;
tlli_info->tlli.ptmsi = new_bss_ptmsi;
} else if (parse_ctx->tlli_enc && parse_ctx->llc && !tlli_info) {
/* Unknown SGSN TLLI */
} else if (parse_ctx->tlli_enc && parse_ctx->new_ptmsi_enc && !tlli_info &&
!peer->cfg->patch_ptmsi) {
/* A new P-TMSI has been signalled in the message with an unknown
* TLLI, create a new tlli_info */
uint32_t new_ptmsi;
if (!gprs_parse_mi_tmsi(parse_ctx->new_ptmsi_enc, GSM48_TMSI_LEN,
&new_ptmsi)) {
LOGP(DGPRS, LOGL_ERROR,
"Failed to parse new PTMSI (TLLI is %08x)\n",
parse_ctx->tlli);
return tlli_info;
}
LOGP(DGPRS, LOGL_INFO,
"Adding TLLI %08x to list (SGSN, new P-TMSI is %08x)\n",
parse_ctx->tlli, new_ptmsi);
tlli_info = gbproxy_tlli_info_alloc(peer);
tlli_info->sgsn_tlli.current = parse_ctx->tlli;;
tlli_info->tlli.current = parse_ctx->tlli;;
tlli_info->sgsn_tlli.ptmsi = new_ptmsi;
tlli_info->tlli.ptmsi = new_ptmsi;
} else if (parse_ctx->tlli_enc && parse_ctx->llc && !tlli_info &&
!peer->cfg->patch_ptmsi) {
/* Unknown SGSN TLLI, create a new tlli_info */
uint32_t new_ptmsi;
tlli_info = gbproxy_tlli_info_alloc(peer);
LOGP(DGPRS, LOGL_INFO, "Adding TLLI %08x to list (SGSN)\n",
parse_ctx->tlli);
gbproxy_attach_tlli_info(peer, now, tlli_info);
/* Setup TLLIs */
tlli_info->sgsn_tlli.current = parse_ctx->tlli;
if (peer->cfg->patch_ptmsi) {
/* TODO: We don't know the local TLLI here, perhaps add
* a workaround that derives a PTMSI from the SGSN TLLI
* and use that to get the missing values. This may
* only happen when the gbproxy has been restarted or a
* tlli_info has been discarded due to age or queue
* length.
*/
tlli_info->tlli.current = 0;
} else {
tlli_info->tlli.current = tlli_info->sgsn_tlli.current;
tlli_info->tlli.current = parse_ctx->tlli;
if (!parse_ctx->new_ptmsi_enc)
return tlli_info;
/* A new P-TMSI has been signalled in the message */
if (!gprs_parse_mi_tmsi(parse_ctx->new_ptmsi_enc,
GSM48_TMSI_LEN, &new_ptmsi)) {
LOGP(DGPRS, LOGL_ERROR,
"Failed to parse new PTMSI (TLLI is %08x)\n",
parse_ctx->tlli);
return tlli_info;
}
LOGP(DGPRS, LOGL_INFO,
"Assigning new P-TMSI %08x\n", new_ptmsi);
/* Setup P-TMSIs */
tlli_info->sgsn_tlli.ptmsi = new_ptmsi;
tlli_info->tlli.ptmsi = new_ptmsi;
} else if (parse_ctx->tlli_enc && parse_ctx->llc && tlli_info) {
uint32_t bss_tlli = gbproxy_map_tlli(parse_ctx->tlli,
tlli_info, 1);

20
openbsc/tests/gbproxy/gbproxy_test.ok
View File

@ -1626,6 +1626,7 @@ Peers:
NSEI 4096, BVCI 4098, not blocked, RAI 112-332-16464-96
RAID patched (BSS ): 2
RAID patched (SGSN): 1
TLLI from SGSN unknown : 1
TLLI-Cache: 0
--- Send message from BSS 1 to SGSN, BVCI 0x1002 ---
@ -1743,6 +1744,7 @@ Peers:
RAID patched (SGSN): 2
APN patched : 3
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI efe2b700 -> efe2b700, IMSI 12131415161718, AGE 0, IMSI matches
@ -1776,6 +1778,7 @@ Peers:
RAID patched (SGSN): 2
APN patched : 3
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI-Cache: 0
--- RA update ---
@ -1821,6 +1824,7 @@ Peers:
RAID patched (SGSN): 3
APN patched : 4
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI bbc54679/efe2b700 -> bbc54679/efe2b700, IMSI 12131415161718, AGE 0, IMSI matches
@ -1843,6 +1847,7 @@ Peers:
RAID patched (SGSN): 3
APN patched : 4
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI-Cache: 0
--- Bad cases ---
@ -1881,6 +1886,7 @@ Peers:
RAID patched (SGSN): 3
APN patched : 4
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI efe2b700 -> efe2b700, IMSI (none), AGE 0
@ -2282,8 +2288,8 @@ Peers:
TLLI patched (BSS ): 8
TLLI patched (SGSN): 6
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI c00f7304/ead4775a -> efe2b700/e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2319,8 +2325,8 @@ Peers:
TLLI patched (BSS ): 9
TLLI patched (SGSN): 7
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI ead4775a -> e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2344,8 +2350,8 @@ Peers:
TLLI patched (BSS ): 10
TLLI patched (SGSN): 7
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI ead4775a -> e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2369,8 +2375,8 @@ Peers:
TLLI patched (BSS ): 11
TLLI patched (SGSN): 7
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI ead4775a -> e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2394,8 +2400,8 @@ Peers:
TLLI patched (BSS ): 11
TLLI patched (SGSN): 8
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI ead4775a -> e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2463,8 +2469,8 @@ Peers:
TLLI patched (SGSN): 9
P-TMSI patched (BSS ): 1
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI cache size : 1
TLLI-Cache: 1
TLLI ead4775a -> e0543210, IMSI 12131415161718, AGE 0, IMSI matches
@ -2489,8 +2495,8 @@ Peers:
TLLI patched (SGSN): 10
P-TMSI patched (BSS ): 1
P-TMSI patched (SGSN): 2
Patch error: other : 1
Attach Request count : 1
TLLI from SGSN unknown : 1
TLLI-Cache: 0
Gbproxy global:
Invalid Routing Area Identifier : 1