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
This patch adds und uses the function gbproxy_gsm48_to_peer() which
takes a GSM 04.08 message, encapsulates it in BSSGP and LLC, and
sends it to the BSS peer. This function increments vu_gen_tx_bss
which is now used instead of imsi_acq_retries to set the N(U) of the
outgoing message.
Since imsi_acq_retries isn't currently incremented before a Detach
Accept is generated, this patch also fixes the N(U) of such messages.
Sponsored-by: On-Waves ehf
Currently then link_info is not cleaned up completely, when
gbproxy_unregister_link_info is called.
This patch adds a function gbproxy_reset_link that must be defined
externally. This is done in gb_proxy.c, where it resets the IMSI
acquisition.
Sponsored-by: On-Waves ehf
Currently time() is used for age calculations. This time source
may jump either forwards or backwards in time (NTP update, leap
seconds).
This patch replaces the use of time() by using
clock_gettime(CLOCK_MONOTONIC) instead.
Sponsored-by: On-Waves ehf
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
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
The function gbproxy_imsi_acquisition() has a parameter sgsn_nsei
that is alyways equal to tlli_info->sgsn_nsei (if tlli_info is not
NULL).
This patch removes this parameter from gbproxy_imsi_acquisition() and
gbproxy_flush_stored_messages() and accesses tlli_info->sgsn_nsei
instead within these functions.
Sponsored-by: On-Waves ehf
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
Currently the number of iterations when creating a P-TMSI/TLLI is not
limited. It is nevertheless very unlikely that the loop will not
terminate. On the other hand, the number of iterations of every loop
should have an upper bound (loop variant) which wouldn't be the case
here if an arbitrary random generator was used.
This patch limits the number of iterations to 23 and logs an error if
the creation of the indentifier was aborted due to this limit.
Sponsored-by: On-Waves ehf
Currently the IMSI acquisition is not restarted when a RA Update
Request is received. This leads to repeated N(U) in the generated
Ident Request message, which in turn causes the MS to drop the
second of these message. This is bad, when the first Ident Response
has been lost between MS and gbproxy.
This patch changes gbproxy_imsi_acquisition() to handle RA Update
Request messages like Attach Requests.
Sponsored-by: On-Waves ehf
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
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
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
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
This commit changes gbproxy_imsi_acquisition as follows:
tlli_info->mi_data_len is used instead of parse_ctx->imsi to check,
whether the IMSI is known already. Since the function is always
called after gbproxy_update_tlli_ul(), the two values are already
synchronized.
Messages are always flushed when the IMSI gets known, if the current
message is IDENT RESP discard it, otherwise continue processing as
usual.
The 'if' clauses are simplified for better readability.
Sponsored-by: On-Waves ehf
gbprox_process_bssgp_ul has grown quite large mainly by the addition
of IMSI acquisition.
This patch moves that code into several smaller functions. In
addition, the peer resolution which is similar to that in
gbprox_process_bssgp_dl is moved into a separate function, too.
Sponsored-by: On-Waves ehf
This patch removes the patch_mode feature including the related VTY
command patch-mode. Where sensible, the other configuration flags are
queried instead.
In addition, this initial checks in gbprox_process_bssgp_dl() and
gbprox_process_bssgp_ul() have been updated.
The patch mode feature has not been used and was increasingly
difficult to maintain.
Sponsored-by: On-Waves ehf
Currently the stored messages are only removed, when IMSI acquisition
has succeeded. In addition, receiving two ATTACH_REQ messages in
sequence (e.g. due to loss of a Identity Req/Resp message) will not
restart the IMSI acquisition procedure.
This patch adds gbproxy_tlli_info_discard_messages() to clean up the
message list and calls it from gbproxy_delete_tlli() fixing a
potential memory leak. It is also called when an Attach Request
message has been received. In that case the imsi_acq_pending flag is
cleared, too. This would (re-)trigger the IMSI acquisition procedure
at each of these messages. If an Ident Response has been lost,
resending the Ident Request with the same N(U) will not work.
Therefore the N(U) gets incremented on each Ident Request generated
by the gbproxy. The first N(U) used is 256 which shouldn't collide
with the V(UT) used by the SGSN given that P-TMSI patching is enabled
(since a new random TLLI is used initially on every new (no
tlli_info) connection and V(U) starts with zero then).
Ticket: OW#1261
Sponsored-by: On-Waves ehf
Currently all STATUS messages coming from the SGSN are just logged
and dropped. This prevents the PCU from recognising that the
(secondary) SGSN doesn't know about a certain BVCI and might require
a reset procedure.
This patch changes gbprox_rx_sig_from_bss() to forward STATUS
messages with cause "Invalid BVCI" containing a BVCI to the BSS.
Note that this will not forward broken "Invalid BVCI"
messages which do not include a BVCI IE.
Sponsored-by: On-Waves ehf
Currently the gbproxy sends STATUS messages that are not compliant to
GSM 08.18, 10.4.14.1: The BVCI must be included if (and only if) the
cause is either "BVCI blocked" or "BVCI unknown".
This patch adds a missing BVCI to UNKNOWN_BVCI and BVCI_BLOCKED
status messages if the BVCI is available. Otherwise, INV_MAND_INF is
used instead.
Sponsored-by: On-Waves ehf
Currently the numeric TLLI or tlli_info's enable_patching flag is
used to decide, whether a APN shall be patched or the secondary SGSN
shall be used. Using the numeric TLLI imposes a problem, when
TLLI/P-TMSI patching is used, since gbproxy_check_tlli uses the BSS
side TLLI namespace when trying to get the tlli_info.
This patch modifies the gbproxy_check_tlli() function to accept a
tlli_info pointer instead of a numeric TLLI. The tlli_info is already
available when the function is called. Since this a similar approach
has been used by accessing the enable_patching flag directly, this
commit unifies checking by always using this function instead of the
flag outside of gb_proxy_tlli.c.
This fixes the APN patching that doesn't work currently when P-TMSI
patching is enabled.
Sponsored-by: On-Waves ehf
Some messages that are related to the BVC itself must be forwarded to
the secondary SGSN, too.
This patch implements this for BVC-RESET (BVCI != 0) and FLOW-CONTROL-BVC
messages. The resulting acknowledgement messages from the secondary
SGSN are silently dropped. The idea behind this is that the primary
SGSN is responsible for setting up and maintaining the BVC whereas
the secondary SGSN is rather passive and just has to accept it.
Ticket: OW#1258
Sponsored-by: On-Waves ehf
This patch modifies gbprox_process_bssgp_ul() to send the message to
the secondary SGSN if the IMSI has matched and routing to the
secondary SGSN is enabled. The destination for stored messages is
modified accordingly.
Ticket: OW#1261
Sponsored-by: On-Waves ehf
This patch refactors SGSN NSEI handling to support a secondary SGSN.
It adds the following VTY commands:
- secondary-sgsn nsei <0-65534>
- no secondary-sgsn
Sending messages to the secondary SGSN is not yet implemented, but
received messages from such a SGSN would be forwarded to the BSS
peers.
Sponsored-by: On-Waves ehf
This should have been part of the 'Implement IMSI acquisition'
commit, where a similar change has been made for BSS originated PTP
messages.
Sponsored-by: On-Waves ehf
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
Currently when patching is enabled and an error happens when
receiving a message from the SGSN, the patched message is sent back
with the PDU_IN_ERROR IE.
This patch modifies gbprox_rx_sig_from_sgsn() to copy the message
before it is patched, so that the original message can be used with
the STATUS message. gbprox_rx_ptp_from_sgsn() does all checks before
the message is patched, so copying is not necessary.
Since gbprox_rx_sig_from_sgsn() is not called for BSSGP UNITDATA
messages and the msgb is already been copied in the gbprox_relay2peer
function, the relative performance impact is expected to be low.
Note that the PDU IE of STATUS messages received from an MS and
forwarded to the SGSN will not be patched. STATUS messages from the
SGSN are only logged and not forwarded to the MS.
Sponsored-by: On-Waves ehf
This patch adds gbprox_rx_data_from_sgsn() and
gbprox_rx_ptp_from_bss() which contain the PTP message processing
of gbprox_rcvmsg(). The calls to gbprox_process_bssgp_ul() are moved
from gbprox_relay2sgsn() to gbprox_rx_ptp_from_bss() and
gbprox_rx_sig_from_bss().
The goal is, to do all patching (and calls to gbprox_process_bssgp_*)
from within the gbprox_rx_* functions. Doing the patching from within
gbprox_relay2sgsn has the drawback, that the patching code cannot
call gbprox_relay2sgsn() which is needed if a single message shall
trigger a sequence of messages.
Sponsored-by: On-Waves ehf
This patch moves the peer related definitions from gb_proxy.c to
gb_proxy_peer.c and adjusts the prefix of each global symbol to
gbproxy_:
Peer definitions (prefix adjusted to gbproxy_):
peer_ctr_description -> gprs/gb_proxy_peer.c (static)
peer_ctrg_desc -> gprs/gb_proxy_peer.c (static)
*peer_by_* -> gprs/gb_proxy_peer.c
gbproxy_peer_alloc -> gprs/gb_proxy_peer.c
gbproxy_peer_free -> gprs/gb_proxy_peer.c
gbprox_cleanup_peers -> gprs/gb_proxy_peer.c
Sponsored-by: On-Waves ehf
This patch moves several functions and declarations out of gb_proxy.c
to make them reusable by other components and to separate them by
context and task.
Counter enums (prefix is changed to gbproxy_):
enum gbprox_global_ctr -> gprs/gb_proxy.h
enum gbprox_peer_ctr -> gprs/gb_proxy.h
Generic Gb parsing (prefix is changed to gprs_gb_):
struct gbproxy_parse_context -> openbsc/gprs_gb_parse.h
gbprox_parse_dtap() -> gprs/gprs_gb_parse.c
gbprox_parse_llc() -> gprs/gprs_gb_parse.c
gbprox_parse_bssgp() -> gprs/gprs_gb_parse.c
gbprox_log_parse_context() -> gprs/gprs_gb_parse.c
*_shift(), *_match() -> gprs/gprs_gb_parse.c (no prefix)
gbprox_parse_gmm_* -> gprs/gprs_gb_parse.c (static)
gbprox_parse_gsm_* -> gprs/gprs_gb_parse.c (static)
MI testing/parsing (prefix gprs_ added):
is_mi_tmsi() -> gprs/gprs_utils.c
is_mi_imsi() -> gprs/gprs_utils.c
parse_mi_tmsi() -> gprs/gprs_utils.c
TLLI state handling (prefix is changed to gbproxy_):
gbprox_*tlli* -> gprs/gb_proxy_tlli.c
(except gbprox_patch_tlli, gbproxy_make_sgsn_tlli)
Message patching (prefix is changed to gbproxy_):
gbprox_*patch* -> gprs/gb_proxy_patch.c
gbprox_check_imsi -> gprs/gb_proxy_patch.c
Sponsored-by: On-Waves ehf
This patch modifies gbprox_make_bss_ptmsi() to generate a new P-TMSI
when patch_ptmsi is set in the configuration instead of using the
P-TMSI assigned by the SGSN. It modifies gbprox_make_sgsn_tlli() to
either use a foreign TLLI based on the SGSN side P-TMSI or (if there
is none) generate a random TLLI if patch_ptmsi is set. Otherwise, the
TLLI used by the BSS is used.
The seeds for the pseudo-random sequences sre set based on time
initially. Note that these are neither cryptographically safe nor
protected against collisions.
Ticket: OW#1259
Sponsored-by: On-Waves ehf
This patch contains fixes for the TLLI tracking and handling.
It adds and uses gbprox_map_tlli() the map the source TLLI to the
destination TLLI while respecting whether it is current or assigned.
It removes gbprox_register_tlli() from the downlink path. It fixes
TLLI validation and disables the use of the BSSGP TLLI IE.
Sponsored-by: On-Waves ehf
Currently, these messages lead to a parsing error which prevents them
from being processed any further.
This patch sets the return value of gbprox_parse_llc to 1 in these
cases and fixes a segfault which is triggered by any non-04.08
message.
Sponsored-by: On-Waves ehf
Currently gbprox_patch_raid() updates the local MCC/MNC with every
BSS originated message, even if the RAI is an 'old' one.
This patch separates state updating and patching into 2 functions
gbprox_update_current_raid and gbprox_patch_raid. In addition, a
field named old_raid_enc is added to gbproxy_parse_context, which is
used for 'old RAI' IEs in Attach Requests and RA Update Requests.
Only the bssg_raid_enc in BSS originated message is used to update
the BSS side 'local' MCC/MNC.
Sponsored-by: On-Waves ehf
This patch splits the functionality of gbprox_get_detached_tlli_info
into 2 new functions:
- gbprox_tlli_info_alloc to allocate an intialized and detached
tlli_info
- gbprox_detach_tlli_info to detach an already attached tlli_info
Sponsored-by: On-Waves ehf
This patch separates BSS side from SGSN side TLLI/PTMSI tracking. When
TLLI/PTMSI patching is not enabled, the corresponding states shall be
identical. The TLLI/PTMSI state has been moved into the struct
gbproxy_tlli_state and is used twice in gbproxy_tlli_info.
Since the state handling for uplink and downlink messages is
diverging, gbprox_update_state() is replaced by two functions
gbprox_update_state_dl/gbprox_update_state_ul and
gbprox_process_bssgp_message() is replaced by
gbprox_process_bssgp_dl/gbprox_process_bssgp_ul.
Sponsored-by: On-Waves ehf
Don't replace the current TLLI immediately, store it in an additional
'assigned_tlli' field and discard the old TLLI when both sides have
used the new one (see GSM 04.08, 4.7.1.5).
Add an Attach Complete message to test and check, whether the related
field of the corresponding tlli_info struct are set as expected
during the local TLLI validation cycle.
Sponsored-by: On-Waves ehf
Currently the enable_patching field in tlli_info is not updated,
when an IMSI is assigned to a TLLI that is already known.
This patch fixes this in gbprox_update_state() after the call to
gbprox_update_tlli_info().
The number of APN increases and the test output file is updated
accordingly.
Sponsored-by: On-Waves ehf
GSM 24.008 also allows a P-TMSI field in Detach request messages.
This patch adds gbprox_parse_gmm_detach_req() to parse Detach Request
messages which sets the ptmsi field if the IE is present.
In addition, when power_off is set to 1 (MO only), the
invalidate_tlli field is set, since Detach Request message is
expected in this case.
The second detach test (see 'RA update') is modified to use
power_off instead of relying on a Detach Accept from the network.
To make this work, the PTMSI of the RA Update Accept is fixed to
match the TLLI of the Detach Request.
Sponsored-by: On-Waves ehf
Add a separate function to clear the IMSI filter to be used instead of
gbprox_set_patch_filter(cfg, NULL, ...). Albeit it fixes a Coverity
issue (Unchecked return value), it is a false positive, since the
return value is always 0 in these cases. Nevertheless it is more
obvious what happens when an explicit clear function is called. Using
NULL as filter argument of gbprox_set_patch_filter still clears the
filter.
Fixes: Coverity CID 1231255
Sponsored-by: On-Waves ehf
This patch modifies the code to pass a pointer to the tlli_info
around once it has been acquired. To achieve this,
gbprox_register_tlli() and gbprox_update_state() are modified to
return it (if it has been found or created), and gbprox_patch_llc(),
gbprox_patch_bssgp(), and gbprox_update_state_after() are modified to
take it as parameter.
Add a new function gbprox_touch_tlli() to update timestamp and list
ordering for existing tlli_infos.
The motivation behind this patch is to make the tlli_info available to
the patching code and to avoid repeated searches for the same TLLI.
Sponsored-by: On-Waves ehf
The current implementation of this function is O(N), where N is the
number of entries.
The new implementation is O(D), where D is the number of entries that
are going to be deleted.
Sponsored-by: On-Waves ehf
Currently time() is called at several places to control TLLI aging.
Beside calling time() more often than necessary, the decision which
timesource is to be used is coded into the TLLI handling, and testing
complex aging scenarios is cumbersome.
This patch passes the current time as a parameter instead. The call
to time() is moved to gbprox_process_bssgp_message().
Sponsored-by: On-Waves ehf
This patches removes the call to gbprox_remove_stale_tllis()
from gbprox_register_tlli(), so it must be called explicitly now.
The call is now done from within gbprox_update_state_after().
In addition, the TLLI cache size counter is also kept in sync when
gbprox_remove_stale_tllis is called manually. The call to
gbproxy_peer_free() in gbproxy_peer_free() is moved behind the TLLI
to allow for counter updates in gbprox_delete_tlli().
Sponsored-by: On-Waves ehf
This patch refactors that function by separating the actual patch
code into a new function gbproxy_patch_bssgp(), similar to
gbproxy_patch_llc(). The remaining function is renamed to
gbproxy_process_bssgp_message. The existing function
gbproxy_parse_bssgp_message() is renamed to
gbproxy_process_bssgp_message to match gbproxy_parse_llc.
Sponsored-by: On-Waves ehf
This adds a test for gbprox_set_patch_filter() and
gbprox_check_imsi().
It also fixes the masking of the type field when IMSIs are checked by
using GSM_MI_TYPE_MASK (0x07) instead of 0x0f.
Sponsored-by: On-Waves ehf
Jacob Erlbeck