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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

94
src/core/tcp_out.c
View File

@ -454,56 +454,21 @@ tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
}
#endif
/**
* Find out what we can send and send it
/** Send an ACK without data.
*
* @param pcb Protocol control block for the TCP connection to send data
* @return ERR_OK if data has been sent or nothing to send
* another err_t on error
* @param pcb Protocol control block for the TCP connection to send the ACK
*/
err_t
tcp_output(struct tcp_pcb *pcb)
tcp_send_empty_ack(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
input processing code to call us when input processing is done
with. */
if (tcp_input_pcb == pcb) {
return ERR_OK;
}
wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
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.
*
* If data is to be sent, we will just piggyback the ACK (see below).
*/
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)
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) {
@ -521,8 +486,9 @@ tcp_output(struct tcp_pcb *pcb)
#if LWIP_TCP_TIMESTAMPS
pcb->ts_lastacksent = pcb->rcv_nxt;
if (pcb->flags & TF_TIMESTAMP)
if (pcb->flags & TF_TIMESTAMP) {
tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
}
#endif
#if CHECKSUM_GEN_TCP
@ -539,6 +505,52 @@ tcp_output(struct tcp_pcb *pcb)
pbuf_free(p);
return ERR_OK;
}
/**
* Find out what we can send and send it
*
* @param pcb Protocol control block for the TCP connection to send data
* @return ERR_OK if data has been sent or nothing to send
* another err_t on error
*/
err_t
tcp_output(struct tcp_pcb *pcb)
{
struct tcp_seg *seg, *useg;
u32_t wnd, snd_nxt;
#if TCP_CWND_DEBUG
s16_t i = 0;
#endif /* TCP_CWND_DEBUG */
/* First, check if we are invoked by the TCP input processing
code. If so, we do not output anything. Instead, we rely on the
input processing code to call us when input processing is done
with. */
if (tcp_input_pcb == pcb) {
return ERR_OK;
}
wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
seg = pcb->unsent;
/* 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.
*
* If data is to be sent, we will just piggyback the ACK (see below).
*/
if (pcb->flags & TF_ACK_NOW &&
(seg == NULL ||
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
return tcp_send_empty_ack(pcb);
}
/* 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);