jolly has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bts/+/34423?usp=email )
Change subject: ASCI: Ignore LAPD frames from MS, while the uplink is not active ......................................................................
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 --- M src/common/l1sap.c 1 file changed, 34 insertions(+), 3 deletions(-)
Approvals: pespin: Looks good to me, but someone else must approve fixeria: Looks good to me, approved Jenkins Builder: Verified
diff --git a/src/common/l1sap.c b/src/common/l1sap.c index 13d271e..b828307 100644 --- a/src/common/l1sap.c +++ b/src/common/l1sap.c @@ -1810,9 +1810,20 @@ 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;