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Fixed bug #28106: dup ack for fast retransmit could have non-zero length

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This commit is contained in:
goldsimon 2009-12-03 19:42:35 +00:00
parent 32acb82bc0
commit 7d46e06824
4 changed files with 65 additions and 48 deletions
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4
CHANGELOG
View File

@ -46,6 +46,10 @@ HISTORY
++ Bugfixes:
2009-12-03: Simon Goldschmidt
* tcp.h, tcp_in.c, tcp_out.c: Fixed bug #28106: dup ack for fast retransmit
could have non-zero length
2009-12-02: Simon Goldschmidt
* tcp_in.c: Fixed bug #27904: TCP sends too many ACKs: delay resetting
tcp_input_pcb until after calling the pcb's callbacks

4
src/core/tcp_in.c
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@ -1267,7 +1267,7 @@ tcp_receive(struct tcp_pcb *pcb)
} else {
/* We get here if the incoming segment is out-of-sequence. */
tcp_ack_now(pcb);
tcp_send_empty_ack(pcb);
#if TCP_QUEUE_OOSEQ
/* We queue the segment on the ->ooseq queue. */
if (pcb->ooseq == NULL) {
@ -1376,7 +1376,7 @@ tcp_receive(struct tcp_pcb *pcb)
}
} else {
/* The incoming segment is not withing the window. */
tcp_ack_now(pcb);
tcp_send_empty_ack(pcb);
}
} else {
/* Segments with length 0 is taken care of here. Segments that

104
src/core/tcp_out.c
View File

@ -454,6 +454,58 @@ tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
}
#endif
/** Send an ACK without data.
*
* @param pcb Protocol control block for the TCP connection to send the ACK
*/
err_t
tcp_send_empty_ack(struct tcp_pcb *pcb)
{
struct pbuf *p;
struct tcp_hdr *tcphdr;
u8_t optlen = 0;
#if LWIP_TCP_TIMESTAMPS
if (pcb->flags & TF_TIMESTAMP) {
optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
}
#endif
p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen, PBUF_RAM);
if (p == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
return ERR_BUF;
}
LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
/* remove ACK flags from the PCB, as we send an empty ACK now */
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
tcphdr = tcp_output_set_header(pcb, p, optlen, htonl(pcb->snd_nxt));
/* NB. MSS option is only sent on SYNs, so ignore it here */
#if LWIP_TCP_TIMESTAMPS
pcb->ts_lastacksent = pcb->rcv_nxt;
if (pcb->flags & TF_TIMESTAMP) {
tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
}
#endif
#if CHECKSUM_GEN_TCP
tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
IP_PROTO_TCP, p->tot_len);
#endif
#if LWIP_NETIF_HWADDRHINT
ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
IP_PROTO_TCP, &(pcb->addr_hint));
#else /* LWIP_NETIF_HWADDRHINT*/
ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
IP_PROTO_TCP);
#endif /* LWIP_NETIF_HWADDRHINT*/
pbuf_free(p);
return ERR_OK;
}
/**
* Find out what we can send and send it
@ -465,14 +517,11 @@ tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
err_t
tcp_output(struct tcp_pcb *pcb)
{
struct pbuf *p;
struct tcp_hdr *tcphdr;
struct tcp_seg *seg, *useg;
u32_t wnd, snd_nxt;
#if TCP_CWND_DEBUG
s16_t i = 0;
#endif /* TCP_CWND_DEBUG */
u8_t optlen = 0;
/* First, check if we are invoked by the TCP input processing
code. If so, we do not output anything. Instead, we rely on the
@ -486,12 +535,6 @@ tcp_output(struct tcp_pcb *pcb)
seg = pcb->unsent;
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
/* If the TF_ACK_NOW flag is set and no data will be sent (either
* because the ->unsent queue is empty or because the window does
* not allow it), construct an empty ACK segment and send it.
@ -501,44 +544,13 @@ tcp_output(struct tcp_pcb *pcb)
if (pcb->flags & TF_ACK_NOW &&
(seg == NULL ||
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
#if LWIP_TCP_TIMESTAMPS
if (pcb->flags & TF_TIMESTAMP)
optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
#endif
p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen, PBUF_RAM);
if (p == NULL) {
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
return ERR_BUF;
}
LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
/* remove ACK flags from the PCB, as we send an empty ACK now */
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
return tcp_send_empty_ack(pcb);
}
tcphdr = tcp_output_set_header(pcb, p, optlen, htonl(pcb->snd_nxt));
/* NB. MSS option is only sent on SYNs, so ignore it here */
#if LWIP_TCP_TIMESTAMPS
pcb->ts_lastacksent = pcb->rcv_nxt;
if (pcb->flags & TF_TIMESTAMP)
tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
#endif
#if CHECKSUM_GEN_TCP
tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
IP_PROTO_TCP, p->tot_len);
#endif
#if LWIP_NETIF_HWADDRHINT
ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
IP_PROTO_TCP, &(pcb->addr_hint));
#else /* LWIP_NETIF_HWADDRHINT*/
ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
IP_PROTO_TCP);
#endif /* LWIP_NETIF_HWADDRHINT*/
pbuf_free(p);
return ERR_OK;
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
#if TCP_OUTPUT_DEBUG

1
src/include/lwip/tcp.h
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@ -125,6 +125,7 @@ void tcp_fasttmr (void);
/* Only used by IP to pass a TCP segment to TCP: */
void tcp_input (struct pbuf *p, struct netif *inp);
/* Used within the TCP code only: */
err_t tcp_send_empty_ack(struct tcp_pcb *pcb);
err_t tcp_output (struct tcp_pcb *pcb);
void tcp_rexmit (struct tcp_pcb *pcb);
void tcp_rexmit_rto (struct tcp_pcb *pcb);