The Link Layer Discovery Protocol is using a Tag Length Value (TLV)
structure. What is different is that the tag and length do not stop
at byte boundaries.
This commit introduces methods to msgb and tlv to be able to create
such a tag/length header and a way to parse it using the tlv_parse
routine. When it comes to parsing we have an issue that the new
TLV_TYPE_T7L9V should not be mixed with the other types inside the
same tlv definition. This is due the bitshifting required to
identify the tag.
The code likely requires work on big-endian machines but so does
most of the other code as well.
Currently it takes 3s to establish a SAPI 3 SACCH connection with
osmo-bts. This is due to the fact, that a broken SABME request is
sent first and and is ignored by the MS. Then, after a T200 timeout
(2s) the SABME command is sent again (this time correctly) and
answered by the MS.
The first SABME message is broken (it has a length field of 3 and
ends with 3 bytes from the tail of the original RSL message),
because of it is expected throughout lapdm.c that msg buffers
containing RSL have msg->l2h == msg->data. Some abis input drivers
fulfill this but IPA doesn't, thus the 3 bytes of the IPA header
are still part of the msg and confuse length computation.
Since internal fields of the msg are modified directly, this is
difficult to see.
This patch adds a new function msgb_pull_to_l3() that explicitely
skips over all headers prepending L3 and therefore resets l1h and
l2h. This function is then used instead of msgb_pull_l2h() which
only worked correctly when msg->l2h == msg->data. In addition,
code manipulating msg->tail and msg->len directly has been replaced
by calls to msgb_trim().
Note that this patch does not fix all issues of this case in the LADP
related code.
Ticket: SYS#192
Sponsored-by: On-Waves ehf
Since e.g. the IPA input driver leaves it's specific header in front
of msg->l2h, so that msg->l2h != msg->data. The lapdm code does not expect this at least in
rslms_rx_rll_est_req().
This patch modifies the test program to add a dummy L1 header to
generated messages (unless the test would abort when doing so).
Note that the ok file reflects the current state which is not
correct.
Sponsored-by: On-Waves ehf
This function works like osmo_hexdump() and returns a static buffer
containing hex bytes along with markers for the layers.
Note that it uses osmo_hexdump() internally, thus a call to
msgb_hexdump() invalidates the buffer that has been returned by an
earlier call to osmo_hexdump(). In short: don't mix them in a single
call printf().
Sponsored-by: On-Waves ehf
This test case processes RSL establish requests for SMS (SAPI 3)
on the SDCCH and the SACCH channels. The TX queues are checked
after processing each message.
Ticket: SYS#192
Sponsored-by: On-Waves ehf
Currently w[14]/w[15] and w[18]/w[19] are swapped in range 256 format
decoding in gsm48_decode_freq_list().
This patch fixes this.
Sponsored-by: On-Waves ehf
The legacy 7bit conversion functions (those without the '_n_' in the
name) gave wrong return values on 64 bit platforms due to unproper
signed/unsigned conversions and the usage of SIZE_MAX.
This patch fixes this by using a smaller max size (see
GSM_7BIT_LEGACY_MAX_BUFFER_SIZE, currently set to 64k) for the legacy
wrappers and by using unsigned int for max_septets.
In addition, there are tests now that check the return values of
legacy encoding and decoding.
Sponsored-by: On-Waves ehf
abis_nm_pchan4chcomb will return a pchan for a given channel
combination but returned a value of the channel combination.
Fix it to return the physical channel combination.
Fixes: Coverity CID 1040767
In the osmo-bts and libosmo-abis code the hexdump routine is used
for every incoming/outgoing packet (including voice frames) and the
usage of snprintf showed up inside profiles.
There is a semantic change when more than 4096 characters are used.
The code will now truncate at byte boundaries (and not nibbles).
Code:
static const int lengths[] = { 23, 1000, 52 };
char buf[4096];
int i;
for (i = 0; i < 30000; ++i)
char *res = osmo_hexdump(buf, lengths[i & 3]);
Results:
before: after:
real 0m3.233s real 0m0.085s
user 0m3.212s user 0m0.084s
sys 0m0.000s sys 0m0.000s
The filter_fn has not been copied into the new structure breaking
the imsi and other filters in OpenBSC. Looking at the code we should
also introduce a callback for the reset of the context so we could
use subscr_get/subscr_put on the subscriber structure.
Okay. this comment thing has not worked (I totally forgot about it).
I think either we try to find ABI breakages with tools or we use
#error macros and check for a version...
Currently the field nsvci_is_valid is set to 0 in the NSVC object
returned by gprs_nsvc_create(). This was a semantic change probably
introduced by commit 5e6d679d. As a result, NSVC created via the VTY
have this flag set to 0 causing RESET_ACK messages to be rejected.
This patch changes the default behaviour of gprs_nsvc_create() to
always set this flag. So it must be set to 0 explicitely if needed
which is more intuitive and thus less error prone.
It fixes breaking connections from the Gbproxy to the SGSN.
Ticket: OW#874
Sponsored-by: On-Waves ehf
Currently those messages are answered by a NS_STATUS message when
received on an uninitialised (no NS_RESET hat been seen yet) NS_VC
which violates GPP TS 08.16 7.3.1 and 7.4.1.
This patch adds checks to gprs_ns_vc_create() and eventually returns
before the error NS_STATUS message is generated.
Sponsored-by: On-Waves ehf
Several messages shall not be answered when a RESET hasn't been
received on a NS-VC:
- NS_RESET_ACK (see 3GPP TS 08.16, 7.3.1)
- NS_ALIVE_ACK (see 3GPP TS 08.16, 7.4.1)
- NS_STATUS (see 3GPP TS 08.16, 7.5.1)
Sponsored-by: On-Waves ehf
I have a crash with an older libosmocore and the sysmobts. I
am not sure how we can have a release for a channel where the
lapdm_channel has not gone through lapdm_channel_init. But to
prevent the crash we can promise lapdm_channel_exit to be idempotent.
It has been idempotent since f5a079f739
When a RESET is received on the same link with a different NSVCI from
a BSS on a dynamically created NS connection do not patch the nsvc
object but create a new one instead. Thus the NSVCI is never modified
at a nsvc object after the NS-VC has been established.
Sponsored-by: On-Waves ehf
This modifies the NS stack's behavior to accept RESET and RESET_ACK
NSEI changes for NS-VC dynamically created by RESET messages from
BSSes. This feature is not used for NS-VC configured via VTY or NS-VC
to a SGSN.
Sponsored-by: On-Waves ehf
This changes the implementations for the reception of RESET and
RESET_ACK to be compatible with 3GPP TS 08.16, 7.3.1:
- Just send a RESET_ACK with correct values back to the SGSN when a
RESET with an invalid NSVCI or NSEI has been received.
- Check RESET_ACK for matching NSEI and NSVCI.
- Ignore unexpected RESET_ACKs.
In addition, use RESET_ACK from a BSS to update the BSS source
address based on the NSVCI to be tolerant with changing UDP source
addresses/ports.
Sponsored-by: On-Waves ehf
Add a test handling proper and mismatching RESETs. The latter may
occur, when ports change within a NS-VC without the SGSN getting
notice.
This tests for the behavior of the NS protocol stack for RESET and
RESET_ACK messages which changing/invalid NSEI and NSVCI like it is
being described in 3GPP TS 08.16, 7.3.1.
Sponsored-by: On-Waves ehf
Holger Hans Peter Freyther
Harald Welte