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Fix BUG#27445: grow cwnd with every duplicate ACK

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This commit is contained in:
kieranm 2009-10-28 15:13:51 +00:00
parent af3b796488
commit 71ddff4964
2 changed files with 37 additions and 34 deletions
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3
CHANGELOG
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@ -46,6 +46,9 @@ HISTORY
++ Bugfixes:
2009-10-27: Kieran Mansley
* tcp_in.c: fix BUG#27445: grow cwnd with every duplicate ACK
2009-10-25: Simon Goldschmidt
* tcp.h: bug-fix in the TCP_EVENT_RECV macro (has to call tcp_recved if
pcb->recv is NULL to keep rcv_wnd correct)

68
src/core/tcp_in.c
View File

@ -793,44 +793,44 @@ tcp_receive(struct tcp_pcb *pcb)
pcb->acked = 0;
if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
if (pcb->unacked != NULL) {
++pcb->dupacks;
if (pcb->dupacks >= 3) {
if (!(pcb->flags & TF_INFR)) {
/* This is fast retransmit. Retransmit the first unacked segment. */
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %"U16_F" (%"U32_F"), fast retransmit %"U32_F"\n",
(u16_t)pcb->dupacks, pcb->lastack,
ntohl(pcb->unacked->tcphdr->seqno)));
tcp_rexmit(pcb);
/* Set ssthresh to max (FlightSize / 2, 2*SMSS) */
/*pcb->ssthresh = LWIP_MAX((pcb->snd_max -
pcb->lastack) / 2,
2 * pcb->mss);*/
/* Set ssthresh to half of the minimum of the current cwnd and the advertised window */
if (pcb->cwnd > pcb->snd_wnd)
pcb->ssthresh = pcb->snd_wnd / 2;
else
pcb->ssthresh = pcb->cwnd / 2;
++pcb->dupacks;
/* The minimum value for ssthresh should be 2 MSS */
if (pcb->ssthresh < 2*pcb->mss) {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: The minimum value for ssthresh %"U16_F" should be min 2 mss %"U16_F"...\n", pcb->ssthresh, 2*pcb->mss));
pcb->ssthresh = 2*pcb->mss;
}
pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
pcb->flags |= TF_INFR;
} else {
/* Inflate the congestion window, but not if it means that
the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
if (pcb->dupacks >= 3) {
if (!(pcb->flags & TF_INFR) && pcb->unacked != NULL) {
/* This is fast retransmit. Retransmit the first unacked segment. */
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %"U16_F" (%"U32_F"), fast retransmit %"U32_F"\n",
(u16_t)pcb->dupacks, pcb->lastack,
ntohl(pcb->unacked->tcphdr->seqno)));
tcp_rexmit(pcb);
/* Set ssthresh to max (FlightSize / 2, 2*SMSS) */
/*pcb->ssthresh = LWIP_MAX((pcb->snd_max -
pcb->lastack) / 2,
2 * pcb->mss);*/
/* Set ssthresh to half of the minimum of the current cwnd and the advertised window */
if (pcb->cwnd > pcb->snd_wnd)
pcb->ssthresh = pcb->snd_wnd / 2;
else
pcb->ssthresh = pcb->cwnd / 2;
/* The minimum value for ssthresh should be 2 MSS */
if (pcb->ssthresh < 2*pcb->mss) {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: The minimum value for ssthresh %"U16_F" should be min 2 mss %"U16_F"...\n", pcb->ssthresh, 2*pcb->mss));
pcb->ssthresh = 2*pcb->mss;
}
pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
pcb->flags |= TF_INFR;
} else {
/* Inflate the congestion window, but not if it means that
the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss;
}
}
} else {
pcb->dupacks = 0;
}
if (pcb->unacked == NULL && pcb->unsent == NULL)
pcb->dupacks = 0;
} else {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupack averted %"U32_F" %"U32_F"\n",
pcb->snd_wl2 + pcb->snd_wnd, right_wnd_edge));