From faf1f64a2d0a54d37616a8bec8691346ab792cde Mon Sep 17 00:00:00 2001 From: Holger Hans Peter Freyther Date: Thu, 23 Jun 2011 17:53:27 -0400 Subject: 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. --- openbsc/src/gprs/gprs_llc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'openbsc/src/gprs/gprs_llc.c') 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; -- cgit v1.2.3