Commit Graph

100 Commits

Author SHA1 Message Date
Harald Welte 53373bca8f move gsm_04_08_gprs.h to libosmocore
This requres the corresponding commit in libosmocore.
2016-04-29 13:10:37 +02:00
Neels Hofmeyr c9ac20ea43 gbproxy_test: assert msg allocation (CID #57873) 2016-04-16 13:33:22 +02:00
Daniel Willmann 537d480f39 gprs/gb_proxy: Use RAND_bytes for gbproxy TLLI/TMSI allocation
This change has some implications for the test case. It manipulated
bss_ptmsi_state and sgsn_tlli_state variables to make the output of
rand_r() and thus the TLLI/TMSI used predictable.
This possibility is gone when using RAND_bytes() so instead it is
overridden by a function that returns a deterministic sequence of values
(0x00dead00, 0x00dead01, ...). The test cases are adapted to expect
these values instead of the pseudo random values before.

The gbproxy_test stdout file changes as well, but only where the
TLLI/TMSI is displayed (in the hex dumps as well as the TLLI cache
entries).  All other output is the same.
2015-10-13 10:20:26 +02:00
Daniel Willmann d1554ecb78 gbproxy/test: Add and call cleanup_test function
This (currently empty) function is meant to contain code that cleans
up the left-overs of the test functions. This is needed by the next
commit to reset the RAND_bytes sequence.
2015-10-13 10:18:34 +02:00
Holger Hans Peter Freyther daaea0c84f 64bit: Fix compiler warnings in regard to 64bit
vty_interface_layer3.c:584:4: warning: format '%d' expects argument of type 'int', but argument 3 has type 'long unsigned int' [-Wformat=]
    sizeof(subscr->extension)-1, VTY_NEWLINE);
2015-08-03 12:01:44 +02:00
Holger Hans Peter Freyther 8e6ecc9667 misc: Fix warnings about size of size_t in printf
Fixes warnings like:

warning: format '%d' expects argument of type 'int', but argument 3 has type 'long int' [-Wformat]
2015-04-23 17:01:09 -04:00
Holger Hans Peter Freyther c6e32ad0b8 Partial revert "Fix most compiler warnings with gcc-4.9.2"
Most of the "fixes" have nothing to do with gcc-4.9.2 but are a
question of ABI/Architecture (e.g. x86 vs. AMD64). Revert these
for now.

This partially reverts commit 7b1d25a11e.

abis_test.c: In function ‘test_simple_sw_config’:
abis_test.c:68:2: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
  printf("Start: %ld len: %zu\n", descr[0].start - simple_config, descr[0].len);
  ^
abis_test.c: In function ‘test_dual_sw_config’:
abis_test.c:111:2: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
  printf("Start: %ld len: %zu\n", descr[0].start - dual_config, descr[0].len);
  ^
abis_test.c:115:2: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
  printf("Start: %ld len: %zu\n", descr[1].start - dual_config, descr[1].len);
  ^
abis_test.c: In function ‘test_sw_selection’:
abis_test.c:132:2: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
  printf("Start: %ld len: %zu\n", descr[0].start - load_config, descr[0].len);
  ^
abis_test.c:136:2: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
  printf("Start: %ld len: %zu\n", descr[1].start - load_config, descr[1].len);
2015-01-02 11:42:38 +01:00
Harald Welte 7b1d25a11e Fix most compiler warnings with gcc-4.9.2 2015-01-01 12:32:03 +01:00
Jacob Erlbeck dcfd456640 gprs: Move TLV parser functions to gprs_utils.c and rename them
Currently the parser functions for single information elements are
defined within gprs_gb_parse.c and not exported explicitely. In
addition they are named like libosmocore's TLV parser functions and
do not have a proper name prefix. Since it is planned to use them for
other protocols, they need to be globally accessible.

This patch moves them to gprs_utils.c and renames them.

The new names are:
    lv_shift             -> gprs_shift_lv
    v_fixed_shift        -> gprs_shift_v_fixed
    lv_shift             -> gprs_shift_lv
    v_fixed_shift        -> gprs_shift_v_fixed

In the long term, these functions should be moved to libosmocore (and
renamed again).

Sponsored-by: On-Waves ehf
2014-12-23 15:08:52 +01:00
Jacob Erlbeck 59ac49dc1f gbproxy: Reset TLLIs when the link_info is found by IMSI/P-TMSI
Currently when the MS does a re-attach without doing a proper detach
first, the gbproxy uses the old local TLLI if patching and the keep
mode are enabled. This leads to a failing attachment procedure when
TLLI patching is also enabled.

This patch changes gbproxy_update_link_state_ul to reset all TLLIs
within the link_info if the message contains an unknown TLLI and an
MI. This is generally the case with Attach Request messages.

The gbproxy_get_link_info_ul gets an additional tlli_is_valid
output parameter that is set, when a TLLI was present and found.
This flag is then used instead of checking tlli.current == 0 to
set TLLI/P-TMSI e.g. Attach Requests when a link_info was already
present for the P-TMSI/IMSI used in such a request.

Ticket: OW#1324
Sponsored-by: On-Waves ehf
2014-12-02 09:00:09 +01:00
Jacob Erlbeck 9d0fb1e97a gbproxy/test: Extend test_gbproxy_keep_info
Add new test message sequences:
  - Normal attach (with IMSI) after detach (ok)
  - Normal attach (with local TLLI) after detach (ok)
  - Unexpected attach (with IMSI) after successful TLLI validation (fails)
  - Unexpected attach (with P-TMSI) after successful TLLI validation (fails)

Ticket: OW#1324
Sponsored-by: On-Waves ehf
2014-11-05 00:26:34 +01:00
Jacob Erlbeck c37ef6cd0e gbproxy: Patch BSSGP P-TMSI in PAGING PS messages
Currently the P-TMSI IE in PAGING_PS is not patched.

This commit adds code to patch BSSGP P-TMSI IE in
gbproxy_patch_bssgp independently from the P-TMSI patching at the LLC
layer. It also extends gbproxy_update_link_state_dl to use the IMSI
to find the link_info if the TLLI is not present in the message.

Note that the spec (GSM 08.18, 7.2) requires to use of the P-TMSI
instead of the IMSI to select the MS if that IE is available.
Nevertheless as long as the IMSI is always present in downlink BSSGP
messages and as long as the optional P-TMSI refers to the same MS
(which is the case currently), this is not an issue.

Sponsored-by: On-Waves ehf
2014-10-27 11:59:28 +01:00
Jacob Erlbeck 91e9f555b6 gbproxy: Fix P-TMSI generation for repeated Attach Accept messages
Currently, when P-TMSI patching is enabled, a new BSS P-TMSI is
generated for each Attach Accept. So two duplicated, subsequent
Attach Accept messages will be mapped to different BSS side P-TMSI.
Because the last one will replace former ones in the link_info
struct, the MS will fail to access the SGSN if it uses the former
P-TMSI to derive the new TLLI.

This patch checks the SGSN P-TMSI already assigned to the link_info
and only generates a new BSS P-TMSI on mismatch (or if the BSS P-TMSI
hasn't been set yet).

Ticket: OW#1322
Sponsored-by: On-Waves ehf
2014-10-27 11:17:11 +01:00
Jacob Erlbeck e99c333d61 gbproxy/test: Add test case for repeated and otherwise bad messages
This adds a test case to check gbproxy's behaviour when processing
two subsequent but identical Attach Accept messages.

Ticket: OW#1322
Sponsored-by: On-Waves ehf
2014-10-27 11:12:22 +01:00
Jacob Erlbeck fb83ed32d2 gbproxy/test: Add expect_msg checks to test_gbproxy_keep_info
This patch adds assertions to check the LLC/GMM message received from
the gbproxy by the test framework within the function
test_gbproxy_keep_info.

It also fixes the source address of the DETACH ACC messages.

Sponsored-by: On-Waves ehf
2014-10-27 10:51:40 +01:00
Jacob Erlbeck c79beec8f6 gbproxy/test: Don't assign a variable within OSMO_ASSERT (Coverity)
Coverity complains about having side effects in OSMO_ASSERT argument
expressions. This would be an issue in this case, because that
variable is only reference in other OSMO_ASSERT expressions.

Nevertheless this patch changes this to assign the variable outside
of OSMO_ASSERT.

Fixes: Coverity CID 1244239
Sponsored-by: On-Waves ehf
2014-10-27 09:45:28 +01:00
Jacob Erlbeck b36032cb27 gbproxy: Use a separate regexp for routing
Currently one regexp ('patching') is used for all matching.

This patch adds a second category 'routing' which is exclusively used
for SGSN selection. It also adds a corresponding VTY command:

  - match-imsi patching RE : MS related patching (currently APN)
  - match-imsi routing RE  : Select secondary SGSN on match only
  - no match-imsi          : Clear all filter expressions

Ticket: OW#1258
Sponsored-by: On-Waves ehf
2014-10-09 18:06:30 +02:00
Jacob Erlbeck 9ccc41ea05 gbproxy: Cleanup match config after tests
Currently, patch filter configurations are leaking between tests.

This adds a call to gbproxy_clear_patch_filter() to the end of each
test that calls gbproxy_set_patch_filter().

Sponsored-by: On-Waves ehf
2014-10-09 18:04:14 +02:00
Jacob Erlbeck 9a83d7af55 gbproxy: Refactor IMSI matching
The current implementation makes it difficult to add further match
expressions.

This patch adds a new struct gbproxy_match that contains the fields
needed for each match expression. The matches (config) and the
results (link_info) are stored in arrays. All related functions are
updated to use them. The old fields in the config structure are
removed.

Sponsored-by: On-Waves ehf
2014-10-09 18:02:33 +02:00
Jacob Erlbeck 55ec2bf97f gbproxy/test: Add expect_msg checks to test_gbproxy_ra_patching
This patch adds assertions to check the LLC/GMM message received from
the gbproxy by the test framework within the function
test_gbproxy_ra_patching.

Sponsored-by: On-Waves ehf
2014-10-09 18:01:48 +02:00
Jacob Erlbeck acfaff38db gbproxy/test: Save and check received messages
Currently the only way to check, whether the right message have been
generated is to look into the generated text output. This is
error-prone if there are many messages.

This patch adds a way to optionally store all received messages into
a FIFO. They can then be checked by calling expect_msg() which
removes the first message from the FIFO and returns a pointer to it
or NULL if there is none. The pointer is only valid until the next
call to this function.

A few convenience functions are added to check for common message
types:

  - expect_gmm_msg checks for certain GSM 04.08 messages in LLC/GMM
  - expect_llc_msg checks for arbitrary LLC messages in BSSGP/UD
  - expect_bssgp_msg checks for arbitrary BSSG messages

Each of their arguments can be set by MATCH_ANY to ignore it while
matching. On success, they return a pointer to a statically
allocated struct containing the pointer to the msg and the full parse
context.

Recording is enabled by setting the global variable received_messages
to a pointer to a struct llist_head. It can be disabled again by
setting it to NULL.

Sponsored-by: On-Waves ehf
2014-10-09 18:01:15 +02:00
Jacob Erlbeck 9c65c8116f gbproxy: Parse Attach Reject messages
That message is currently ignored but should invalidate the TLLI and
de-register the logical link instead.

This patch extends the parser to recognize such messages and to set
the invalidate_tlli flag.

Sponsored-by: On-Waves ehf
2014-10-09 17:48:37 +02:00
Jacob Erlbeck 2bf326186a gbproxy/test: Add invalidation tests to test_gbproxy_keep_info()
The TLLI should also be invalidated:
 - when an Attach Reject info is received from the SGSN
 - when an Attach Req is immediately followed by a Detach Req
 - when an Attach Req is immediately followed by an MT detach
   procedure

To verify that, this patch adds corresponding message sequences to
the test.

Sponsored-by: On-Waves ehf
2014-10-09 17:48:29 +02:00
Jacob Erlbeck ea71b4880c gbproxy/test: Fix IMSI length check (Coverity)
This fixes the IMSI length assertion, which currently uses a
greater-or-equal than zero comparison which always yields true. It is
replaced by a greater than zero check.

Fixes: Coverity CID 1239442

Sponsored-by: On-Waves ehf
2014-10-09 17:47:58 +02:00
Jacob Erlbeck 51fde08b07 gbproxy/test: Fix time calculation in test_gbproxy_tlli_expire()
A single test case still uses time() to obtain the reference time.

This commit fixes this by using the 'now' variable instead, that
contains a fixed time value and does therefore not depend on when the
test is executed.

Sponsored-by: On-Waves ehf
2014-10-09 17:47:30 +02:00
Jacob Erlbeck f8562e362b gbproxy: Rename the field 'enabled_tllis' to 'logical_links'
This field in struct gbproxy_patch_state has involved and holds a
list of all tracked logical links now. Thus the name is modified
accordingly.

Sponsored-by: On-Waves ehf
2014-10-09 17:45:14 +02:00
Jacob Erlbeck 91d2f8a704 gbproxy: Use the term 'link' instead of 'tlli'
Currently in many places where 'tlli' (Temporary Logical Link
Identifier) within identifiers is used, the logical link itself is
meant instead. For instance, the tlli_info contain information about
an LLC logical link including up to four individual TLLI.

To avoid confusion between these concepts, this patch replaces all
'tlli_info' by 'link_info' and a few 'tlli' by 'link'.

Sponsored-by: On-Waves ehf
2014-10-09 17:44:57 +02:00
Jacob Erlbeck 9a7b0d5641 gbproxy: Rename functions related to tlli_info
This patch replaces 'tlli' by 'tlli_info' within the following
function identifiers:
  - gbproxy_delete_tlli
  - gbproxy_delete_tllis
  - gbproxy_remove_stale_tllis
  - gbproxy_touch_tlli
  - gbproxy_unregister_tlli
  - gbproxy_remove_matching_tllis
  - gbproxy_find_tlli -> gbproxy_tlli_info_by_tlli
  - gbproxy_find_tlli_by_* -> gbproxy_tlli_info_by_*

These functions refer to the whole logical link info rather than to a
certain TLLI. So they are renamed to be named consistently with
gbproxy_attach_tlli_info and others.

Sponsored-by: On-Waves ehf
2014-10-09 17:43:53 +02:00
Jacob Erlbeck 8992f30866 gbproxy: Rename identifiers related to IMSI matching
This patch renames gbproxy_check_tlli() to
gbproxy_imsi_matches() and struct tlli_info's
enable_patching to imsi_matches.

It's meant to be more obvious and consistent this way.

Sponsored-by: On-Waves ehf
2014-10-09 17:43:12 +02:00
Jacob Erlbeck 2ec2757def gbproxy/test: Test IMSI acquisition for RA UDP REQ
When a MS is state GMM_REGISTERED enters a new RA, it sends a RA
Update Request which is then handled by a gbproxy that possibly
doesn't have a matching tlli_info. In this case, depending on the
configuration an identification procedure to acquire the IMSI must be
started.

This adds tests to test_gbproxy_imsi_acquisition():
 - IMSI acquisition triggered by a RA Update Request message
 - Reaction to repeated RA Update Request messages, like it could be
   caused by packet loss between PCU and gbproxy.

Sponsored-by: On-Waves ehf
2014-10-09 17:41:06 +02:00
Jacob Erlbeck 91a0e8639a gbproxy: Separate SGSN numeric namespaces
Currently the SGSN side message's TLLI are searched without checking
the originating SGSN. This leads to collisions if both SGSN use the
same P-TMSI for different MS.

With this patch, the SGSN NSEI is stored within the tlli_info and is
used in comparisons to separate the namespaces.

Note that this type of collision cannot happen with BSS numbers,
since the tlli_info are already separated and stored per (BSS) peer.

Sponsored-by: On-Waves ehf
2014-09-19 11:21:35 +02:00
Jacob Erlbeck af952baffc gbproxy/test: Add a test with a P-TMSI collision between two SGSNs
This patch extends test_gbproxy_secondary_sgsn() by the establishment
of a third MS connection using a P-TMSI that has been assigned by the
other SGSN already. It is expected that the entries do not
interfere and are properly retrieved.

Note that these collisions are not handled properly yet.

Sponsored-by: On-Waves ehf
2014-09-19 11:21:24 +02:00
Jacob Erlbeck 2bb4543809 gbproxy/test: Fix Identification Response
At one place, the reply to the second Ident Req contains the wrong
IMSI. That is fixed by this patch.

Sponsored-by: On-Waves ehf
2014-09-19 11:21:13 +02:00
Jacob Erlbeck 1a02442f66 gbproxy: Check other tlli_infos for matching TLLI/P-TMSI
Currently it is possible to create serveral entries referring to the
same P-TMSI/TLLI by using P-TMSI assigment via Attach Accept or
RA Update Accept messages. This can lead to the use of the wrong
tlli_info.

This patch adds gbproxy_remove_matching_tllis() that removes all
conflicting entries. This function is called after the P-TMSIs and
the resulting TLLIs has been set up.

Sponsored-by: On-Waves ehf
2014-09-19 11:21:01 +02:00
Jacob Erlbeck 04f679be73 gbproxy/test: Add test case for P-TMSI assigment
This tests P-TMSI assignment when P-TMSI patching is disabled. A test
with colliding P-TMSI in Attach Accept messages is included.

Note that P-TMSI collisions are not handled properly yet.

Sponsored-by: On-Waves ehf
2014-09-19 11:20:50 +02:00
Jacob Erlbeck 85e5c8f905 gbproxy: Parse RA_UPD_REJ and invalidate TLLI
Since this message puts the MS into DEREGISTERED state (like a detach
procedure), this message is parsed and the invalidate_tlli field is
set accordingly.

Sponsored-by: On-Waves ehf
2014-09-19 11:20:31 +02:00
Jacob Erlbeck 16a3cd3847 gbproxy: Avoid multiple tlli_info entries with the same IMSI
Currently it is possible to create several tlli_info entries with the
same IMSI.

This patch disables this by adding a check before the imsi field
is updated.

Sponsored-by: On-Waves ehf
2014-09-19 10:49:12 +02:00
Jacob Erlbeck 7430da621a gbproxy: Keep tlli_info after detach
Currently a tlli_info entry is deleted when the TLLI gets invalidated
by a Detach message.

This patch introduces the possibility to keep tlli_info entries in
the list. Those entries then have cleared TLLI fields, are marked as
de-registered, and can only be retrieved by a message containing an
IMSI or a P-TMSI.

The following VTY configuration commands are added to the gbproxy
node:
  - tlli-list keep-mode never : Don't keep the entries (default)
  - tlli-list keep-mode re-attach : Only keep them, when a Detach
    message with re-attach required has been received
  - tlli-list keep-mode identified : Only keep entries which are
    associated with an IMSI
  - tlli-list keep-mode always : Keep all entries

Note that at least one of max-length or max-age should be set when
this feature is used to limit the number of entries.

Sponsored-by: On-Waves ehf
2014-09-19 10:46:23 +02:00
Jacob Erlbeck 772a22b529 gbproxy/test: Add test case for tlli_info persistence
This test case consists of a sequence of several attach and detach
procedures. The kind of detach varies (mobile originated, mobile
terminated re-attach required, mobile terminated re-attach not
required, routing area update reject). To main focus is to check that
the tlli_info is de-registered correctly (not accessible via the
TLLI) and that can be re-used afterwards (which is not implemented
yet).

Sponsored-by: On-Waves ehf
2014-09-18 13:40:03 +02:00
Jacob Erlbeck a42fe9f61e gbproxy: Remove gbproxy_register_tlli
This function is a remainder of the initial implemenation that was
not meant for TLLI patching and can be used for the BSS side only.
The SGSN side is already using a composition of more flexible
single purpose functions.

This patch changes the implementation to use a similar approach. The
function is moved to gbproxy_test.c and renamed to register_tlli to
keep the tests intact.

Sponsored-by: On-Waves ehf
2014-09-18 13:21:17 +02:00
Jacob Erlbeck 948c07f490 gbproxy: Fixed RAI patching in Attach Request messages
Currently the RAI in the LLC part of the message is not updated if
the message has been taken from the list of stored messages. The
reason is, that old_raid_matches is update in
gbprox_process_bssgp_ul() but not in gbproxy_flush_stored_messages().

This patch moves the check to gprs_gb_parse_bssgp() which is called
at both places and where other fields like parse_ctx->tlli are set,
too.

In addition, old_raid_matches is replaced by old_raid_is_foreign
since this is clearer in the case when there is no old RAI at all.

Several RAI patch counter assertions are also added to
test_gbproxy_ra_patching().

Sponsored-by: On-Waves ehf
2014-09-18 13:20:58 +02:00
Jacob Erlbeck 991606b57a gbproxy/test: Add/modify test cases
Add a Attach Request message to test_gbproxy_ra_patching, where the
BSSGP RAI differs from the old RAI signalled in the LLC part. This
case had not been tested explicitely yet.

Change the RAI in the first Attach Request in
test_gbproxy_imsi_acquisition from rai_unknown to rai_bss.

Add Detach Requests to test_gbproxy_imsi_acquisition, one for a
incomplete attach procedure and one for an unknown (fresh) TLLI.
In these cases, the acquisition of a IMSI is not necessary and also
doesn't work properly with an E71.

Sponsored-by: On-Waves ehf
2014-09-18 11:26:07 +02:00
Jacob Erlbeck 2fd1ba4c6d gbproxy: Replace 'mi_data' by 'imsi'
Since at all places where mi_data/mi_data_len is used it will always
contain an IMSI. Thus the names of the identifiers have been updated
accordingly for clarity.

Sponsored-by: On-Waves ehf
2014-09-18 11:22:15 +02:00
Jacob Erlbeck 7fb26c2943 gbproxy/test: Add assertions, improve test coverage
This patch add explicit tests for
  - gbproxy_peer_by_bvci
  - gbproxy_peer_by_nsei
  - gbproxy_cleanup_peers
  - gbproxy_peer_by_rai
  - gbproxy_peer_by_lai
  - gbproxy_peer_by_lac
and for messages with an unknown TLLI sent by the SGSN.

Sponsored-by: On-Waves ehf
2014-09-09 10:10:12 +02:00
Jacob Erlbeck ea1698e322 gbproxy/test: Add test cases for IMSI acquisition
If the Attach Request procedure gets restarted e.g. because of a lost
message, all of these messages are stored if IMSI acquisition is in
progress.

This patch adds a test for this case and modifies the dump_peers
function to output the number of stored messages.

Note that the number of stored messages currently increases with each
(repeatedly) received Attach Request which is not the desired behaviour.

Sponsored-by: On-Waves ehf
2014-09-09 10:09:50 +02:00
Jacob Erlbeck 52f070a099 gbproxy/test: Extend P-TMSI patch test by a sequence of RA UDP REQ
This adds a sequence of two RA update procedures to
test_gbproxy_ptmsi_patching(). Each of them assigns a new P-TMSI.

Note that the implementation fails to patch the RAI within the
message labelled 'RA UDP ACC (P-TMSI 3)' and logs 'TLLI sent by the
SGSN is unknown'.

Sponsored-by: On-Waves ehf
2014-09-08 13:34:13 +02:00
Jacob Erlbeck 82add78f89 gbproxy/test: Check APN patching while P-TMSI patching is enabled
This commit adds a single ACT PDP CTX REQ message to
test_gbproxy_ptmsi_patching() to check whether APN patching works in
this case, too.

Note that this doesn't work currently, the APN patch count is not
incremented.

Sponsored-by: On-Waves ehf
2014-09-08 09:27:41 +02:00
Jacob Erlbeck f181f9ec2a gbproxy/test: Add test case for secondary SGSN
This patch adds a case to test the establishment (and shutdown) of
connection between 2 MS and 2 SGSN, where the assignment is based
on each IMSI. Since BVC-RESET and FLOW-CONTROL-BVC will have to be
sent to both SGSN, an ACK is simulated for both.

New functions to generate FLOW-CONTROL-BVC(-ACK) messages are
provided.

It modifies dump_peers to add the string "IMSI matches" to a TLLI dump
line if appropriate.

Note that there is no real support to use a secondary SGSN in the
gbproxy yet, but the test code reflects the expected behaviour when
the feature is implemented.

Sponsored-by: On-Waves ehf
2014-09-08 09:12:02 +02:00
Jacob Erlbeck 5f4ef321a6 gbproxy: Implement IMSI acquisition
To modify or route messages based on the IMSI the latter must be known
when the action shall take place.

This patch modifies the gbproxy to optionally retain and enqueue
messages from the MS while initiating an identification procedure.
Further message processing of the LLC PTP link towards the SGSN will
be done, when the identity of the MS has been acquired.

Note that the N(U) of the LLC GMM SAPI are not adjusted, so it is
possible that adjacent messages of a single LLC link arriving either
at the BSS or the SGSN have the same N(U) and might get discarded,
leading to retransmissions and additional delay.

Note also that retransmissions and packet loss are not yet handled
explicitely. If for instance the generated IDENT REQ gets lost, the
gbproxy will not act on its own. In this case, the MS will time out
and eventually resend the Attach Request on which the gbproxy will
act exactly like before (thus having two Attach Req messages in its
queue, which will both be sent after the Ident Resp arrives).

This has been tested successfully with an E71, needing one
retransmission by the SGSN due to an N(U) collision.

Ticket: OW#1261
Sponsored-by: On-Waves ehf
2014-09-02 09:53:47 +02:00
Jacob Erlbeck 28fe98891f gbproxy/test: Add a test for IMSI acquisition
This patch copies test_gbproxy_ptmsi_patching to
test_gbproxy_imsi_acquisition as a base for a later test for IMSI
acquisition (which is not yet implemented). The idea behind this is
to make the different behaviour visible in the ok file without
compromising the P-TMSI test.

Sponsored-by: On-Waves ehf
2014-09-02 09:53:42 +02:00