diff options
| author | Philipp <pmaier@sysmocom.de> | 2016-12-22 14:15:20 +0100 |
|---|---|---|
| committer | Philipp <pmaier@sysmocom.de> | 2016-12-23 11:19:15 +0100 |
| commit | db142dc59dc8d79d8ee608c9165bc865d240b97d (patch) | |
| tree | a4c1ec7fdece679b7dd252ac321b28c60e3492d2 /openbsc/include/openbsc/gprs_sndcp_xid.h | |
| parent | a191dcd8f01767b266b85578d0fb445d864dfabd (diff) | |
sndcp: Allow empty SNDCP-XID indications
In some rare cases the modem might send a xid indication that does
not contain anything except the version number field. The sgsn
ignors such SNDCP-XID indications by stripping the entire field
from the response. We found a modem in the wild that started to
act problematic when the empty SNDCP-XID was missing in the
response. This patch changes the XID negotiation behaviour in
a way that if a modem should send empty SNDCP-XID indications,
the reply will also contain an empty SNDCP-XID indication. Apart
from that the SNDCP-XID version number is now parsed and echoed
in the response. This ensures that we always reply with the version
number that the modem expects. (The version was 0 in all cases we
observed so far)
Change-Id: I097a770cb4907418f53e620a051ebb8cd110c5f2
Related: OS#1794
Diffstat (limited to 'openbsc/include/openbsc/gprs_sndcp_xid.h')
| -rw-r--r-- | openbsc/include/openbsc/gprs_sndcp_xid.h | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/openbsc/include/openbsc/gprs_sndcp_xid.h b/openbsc/include/openbsc/gprs_sndcp_xid.h index 02904a7d2..e64bc5237 100644 --- a/openbsc/include/openbsc/gprs_sndcp_xid.h +++ b/openbsc/include/openbsc/gprs_sndcp_xid.h @@ -24,7 +24,7 @@ #include <stdint.h> #include <osmocom/core/linuxlist.h> -#define CURRENT_SNDCP_VERSION 0 /* See 3GPP TS 44.065, clause 8 */ +#define DEFAULT_SNDCP_VERSION 0 /* See 3GPP TS 44.065, clause 8 */ #define MAX_ENTITIES 32 /* 3GPP TS 44.065 reserves 5 bit * for compression enitity number */ @@ -197,13 +197,15 @@ enum gprs_sndcp_dcomp_v44_dcomp { /* Transform a list with compression fields into an SNDCP-XID message (dst) */ int gprs_sndcp_compile_xid(uint8_t *dst, unsigned int dst_maxlen, - const struct llist_head *comp_fields); + const struct llist_head *comp_fields, int version); /* Transform an SNDCP-XID message (src) into a list of SNDCP-XID fields */ -struct llist_head *gprs_sndcp_parse_xid(const void *ctx, - const uint8_t * src, - unsigned int src_len, - const struct llist_head *comp_fields_req); +struct llist_head *gprs_sndcp_parse_xid(int *version, + const void *ctx, + const uint8_t *src, + unsigned int src_len, + const struct llist_head + *comp_fields_req); /* Find out to which compression class the specified comp-field belongs * (header compression or data compression?) */ |