diff options
| author | Harald Welte <laforge@gnumonks.org> | 2017-07-15 22:32:52 +0200 |
|---|---|---|
| committer | Harald Welte <laforge@gnumonks.org> | 2017-07-15 22:36:10 +0200 |
| commit | 3617fd1cb6eb3e22a1f1482e05a8d1d8cb9016f1 (patch) | |
| tree | 14d012b871bbfed88aeea0e9f825d2049f1aaf44 | |
| parent | e0e2b9e30338b9cfe3892c326d82b4a37860e7f1 (diff) | |
Ensure we don't send dummy UI frames on BCCH for TC=5
When no SI 2bis, nor 2ter, nor 2quater is in use, then the code in
bts_sysinfo_get() will return null, causing the transmission of a dummy
frame (0303012B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B) instead of a
system information message. This is - at least - very odd and might not
be backed by the specification. We should simply send any other system
information message instead of sending a frame that does not have a
valid SI header.
While 030301 might be a valid, empty UI frame on a DCCH, it is not a
valid frame for the BCCH, where the header is structured differently.
In fact, bts_sysinfo_get() should never return NULL and always return a
valid BCCH message.
This bug was found while developing
http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo/Test.ttcn
Change-Id: Ifeaed27d1d7ba9994fb8ce67d660648bcc8efece
Closes: OS#2365
| -rw-r--r-- | src/common/sysinfo.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/common/sysinfo.c b/src/common/sysinfo.c index 9276c7bb..cf863804 100644 --- a/src/common/sysinfo.c +++ b/src/common/sysinfo.c @@ -129,6 +129,10 @@ uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time) else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) return get_si2q_inc_index(bts); + + /* simply send SI2 if we have nothing else to send */ + else + return GSM_BTS_SI(bts, SYSINFO_TYPE_2); break; case 6: return GSM_BTS_SI(bts, SYSINFO_TYPE_3); @@ -136,7 +140,9 @@ uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time) return GSM_BTS_SI(bts, SYSINFO_TYPE_4); } - return NULL; + /* this should never bve reached. We must transmit a BCCH + * message on the normal BCCH in all cases. */ + OSMO_ASSERT(0); } uint8_t num_agch(struct gsm_bts_trx *trx, const char * arg) |