From 0ac827848dd1747c8199f338d71a32111bb01fa5 Mon Sep 17 00:00:00 2001 From: Christian Vogt Date: Fri, 16 Nov 2012 15:30:52 +0100 Subject: [PATCH] tftp_rx: handle resends Re-send ACK for block X in case we receive block X data again while waiting for block X+1. Based on an earlier patch by Marcin Adamski. --- lib/tftp.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/lib/tftp.c b/lib/tftp.c index 7202b94d37824a..832302ed1b79a4 100644 --- a/lib/tftp.c +++ b/lib/tftp.c @@ -591,16 +591,26 @@ static CURLcode tftp_rx(tftp_state_data_t *state, tftp_event_t event) case TFTP_EVENT_DATA: /* Is this the block we expect? */ rblock = getrpacketblock(&state->rpacket); - if(NEXT_BLOCKNUM(state->block) != rblock) { - /* No, log it */ + if( NEXT_BLOCKNUM(state->block) == rblock ) { + /* This is the expected block. Reset counters and ACK it. */ + state->retries = 0; + } + else if( state->block == rblock ) { + /* This is the last recently received block again. Log it and ACK it again. */ + infof(data, + "Received last DATA packet block %d again.\n", + rblock); + } + else { + /* totally unexpected, just log it */ infof(data, "Received unexpected DATA packet block %d, expecting block %d\n", rblock, NEXT_BLOCKNUM(state->block)); break; } - /* This is the expected block. Reset counters and ACK it. */ + + /* ACK this block. */ state->block = (unsigned short)rblock; - state->retries = 0; setpacketevent(&state->spacket, TFTP_EVENT_ACK); setpacketblock(&state->spacket, state->block); sbytes = sendto(state->sockfd, (void *)state->spacket.data,