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Retransmit packet if it didn't receive a MAC layer ack

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adamdunkels 2010-02-03 01:17:54 +00:00
parent d68af249ec
commit e419eb3cc5
1 changed files with 14 additions and 7 deletions
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21
core/net/mac/csma.c
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@ -28,7 +28,7 @@
* *
* This file is part of the Contiki operating system. * This file is part of the Contiki operating system.
* *
* $Id: csma.c,v 1.4 2010/02/02 20:45:58 adamdunkels Exp $ * $Id: csma.c,v 1.5 2010/02/03 01:17:54 adamdunkels Exp $
*/ */
/** /**
@ -103,8 +103,8 @@ send_packet(void)
/* Check if we saw a collission, and if we have a queuebuf with the /* Check if we saw a collission, and if we have a queuebuf with the
packet available. Only retransmit unicast packets. Retransmit packet available. Only retransmit unicast packets. Retransmit
only once, for now. */ only once, for now. */
if(ret == MAC_TX_COLLISION && buf != NULL && if((ret == MAC_TX_COLLISION || ret == MAC_TX_NOACK) &&
!rimeaddr_cmp(&receiver, &rimeaddr_null)) { buf != NULL && !rimeaddr_cmp(&receiver, &rimeaddr_null)) {
struct queued_packet *q; struct queued_packet *q;
q = memb_alloc(&packet_memb); q = memb_alloc(&packet_memb);
@ -115,11 +115,18 @@ send_packet(void)
q->buf = buf; q->buf = buf;
q->retransmits = 0; q->retransmits = 0;
time = mac->channel_check_interval(); if(ret == MAC_TX_COLLISION) {
if(time == 0) { /* If the packet wasn't sent because of a collission, we let the
time = CLOCK_SECOND; other packet get through before we try again. */
time = mac->channel_check_interval();
if(time == 0) {
time = CLOCK_SECOND;
}
time = time + (random_rand() % (3 * time));
} else {
/* If the packet didn't get an ACK, we retransmit immediately. */
time = 0;
} }
time = time + (random_rand() % (3 * time));
ctimer_set(&q->retransmit_timer, time, ctimer_set(&q->retransmit_timer, time,
retransmit_packet, q); retransmit_packet, q);