diff options
author | Holger Hans Peter Freyther <zecke@selfish.org> | 2011-06-23 17:53:27 -0400 |
---|---|---|
committer | Holger Hans Peter Freyther <zecke@selfish.org> | 2012-01-06 18:52:05 +0100 |
commit | faf1f64a2d0a54d37616a8bec8691346ab792cde (patch) | |
tree | cf9f5052348eae7207bceeb9803967686ca3e692 /openbsc/src | |
parent | 26d0fe3c89042ed4008903dbe12c5110d8f9fc48 (diff) |
gprs: Honor GSM 04.64 8.4.2 Receipt of unacknowledged information
GSM 04.64 8.4.2 asks to ignore UI frames if the DLCI is not known,
or if the "(V(UR)- 32) <= N(U) < V(UR)". E.g. if we want to have
V(UR) == 511 and this frame is dropped, we would ignore N(U)'s
0 to 510. Calculate the delta.
The code is based on Jonathan Santos's "LLC UI window" fix but the
issue was discovered independly.
Diffstat (limited to 'openbsc/src')
-rw-r--r-- | openbsc/src/gprs/gprs_llc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c index 77fa879ca..708c4c69c 100644 --- a/openbsc/src/gprs/gprs_llc.c +++ b/openbsc/src/gprs/gprs_llc.c @@ -518,8 +518,9 @@ static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph, rx_llc_xid(lle, gph); break; case GPRS_LLC_UI: - if (gph->seq_tx < lle->vu_recv) { - LOGP(DLLC, LOGL_NOTICE, "TLLI=%08x dropping UI, vurecv %u <= %u\n", + if (gprs_llc_is_retransmit(gph->seq_tx, lle->vu_recv)) { + LOGP(DLLC, LOGL_NOTICE, + "TLLI=%08x dropping UI, N(U=%d) not in window V(URV(UR:%d).\n", lle->llme ? lle->llme->tlli : -1, gph->seq_tx, lle->vu_recv); return -EIO; |