From 0ac827848dd1747c8199f338d71a32111bb01fa5 Mon Sep 17 00:00:00 2001
From: Christian Vogt <christian.vogt@loewe-komp.de>
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 7202b94d37..832302ed1b 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,
--
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