diff options
| author | Andreas Eversberg <jolly@eversberg.eu> | 2023-09-14 16:13:54 +0200 |
|---|---|---|
| committer | jolly <andreas@eversberg.eu> | 2023-09-25 06:22:35 +0000 |
| commit | f5c1cd3889bb52b1166066885e2d65b87692a37e (patch) | |
| tree | 884d5ddaf66cd3bebb0001608bdf3d1c506569b8 | |
| parent | 0978d1df716d59bc8b22c21bed036616b974f850 (diff) | |
ASCI: Ignore LAPD frames from MS, while the uplink is not active
Do not forward any message that is received on the uplink to LAPD while
the uplink is not active. If the MS did not recognize (fast enough) that
the uplink is free, it may continue to transmit LAPD messages. A
response by LAPD to these messages is not desired and not required. If
LAPD would respond, it would cause stopping transmission of UPLINK FREE
messages. No MS could access the uplink anymore.
Note: UPLINK FREE messages are repeated automatically until a different
message is transmitted.
Related: OS#5781
Change-Id: I5075115123055b2997481f56ddf473430a1dc9e3
| -rw-r--r-- | src/common/l1sap.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/src/common/l1sap.c b/src/common/l1sap.c index 13d271ea..b8283077 100644 --- a/src/common/l1sap.c +++ b/src/common/l1sap.c @@ -1810,9 +1810,20 @@ static int l1sap_ph_data_ind(struct gsm_bts_trx *trx, if (lchan->ho.active == HANDOVER_WAIT_FRAME) handover_frame(lchan); - /* report first valid received frame to VGCS talker process */ - if (rsl_chan_rt_is_asci(lchan->rsl_chan_rt) && lchan->asci.talker_active == VGCS_TALKER_WAIT_FRAME) - vgcs_talker_frame(lchan); + if (rsl_chan_rt_is_asci(lchan->rsl_chan_rt)) { + /* report first valid received frame to VGCS talker process */ + if (lchan->asci.talker_active == VGCS_TALKER_WAIT_FRAME) + vgcs_talker_frame(lchan); + /* Do not forward any message that is received on the uplink to LAPD while + * the uplink is not active. If the MS did not recognize (fast enough) that + * the uplink is free, it may continue to transmit LAPD messages. A + * response by LAPD to these messages is not desired and not required. If + * LAPD would respond, it would cause stopping transmission of UPLINK FREE + * messages. No MS could access the uplink anymore. + */ + if (lchan->asci.talker_active != VGCS_TALKER_ACTIVE) + return 0; + } if (L1SAP_IS_LINK_SACCH(link_id)) le = &lchan->lapdm_ch.lapdm_acch; |