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Kieran Mansley - 14th July 2004

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* Fixed whitespace indenting in parts of tcp_in.c
 * Changed adjustment of ssthresh in response to fast retransmit
 * Commented out iteration of unsent list when new ACK received as we no longer put all unacked data on unsent list when retransmitting
This commit is contained in:
kieranm 2004-07-14 09:45:01 +00:00
parent 8d052ecf24
commit c356f560e8
1 changed files with 293 additions and 283 deletions
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576
src/core/tcp_in.c
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@ -700,43 +700,48 @@ tcp_receive(struct tcp_pcb *pcb)
pcb->acked = 0; pcb->acked = 0;
if (pcb->snd_wl1 + pcb->snd_wnd == right_wnd_edge){ if (pcb->snd_wl1 + pcb->snd_wnd == right_wnd_edge){
++pcb->dupacks; ++pcb->dupacks;
if (pcb->dupacks >= 3 && pcb->unacked != NULL) { if (pcb->dupacks >= 3 && pcb->unacked != NULL) {
if (!(pcb->flags & TF_INFR)) { if (!(pcb->flags & TF_INFR)) {
/* This is fast retransmit. Retransmit the first unacked segment. */ /* This is fast retransmit. Retransmit the first unacked segment. */
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %u (%lu), fast retransmit %lu\n", LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %u (%lu), fast retransmit %lu\n",
(unsigned int)pcb->dupacks, pcb->lastack, (unsigned int)pcb->dupacks, pcb->lastack,
ntohl(pcb->unacked->tcphdr->seqno))); ntohl(pcb->unacked->tcphdr->seqno)));
tcp_rexmit(pcb); tcp_rexmit(pcb);
/* Set ssthresh to max (FlightSize / 2, 2*SMSS) */ /* Set ssthresh to max (FlightSize / 2, 2*SMSS) */
pcb->ssthresh = LWIP_MAX((pcb->snd_max - /*pcb->ssthresh = LWIP_MAX((pcb->snd_max -
pcb->lastack) / 2, pcb->lastack) / 2,
2 * pcb->mss); 2 * pcb->mss);*/
/* Set ssthresh to half of the minimum of the currenct cwnd and the advertised window */
if(pcb->cwnd > pcb->snd_wnd)
pcb->ssthresh = pcb->snd_wnd / 2;
else
pcb->ssthresh = pcb->cwnd / 2;
pcb->cwnd = pcb->ssthresh + 3 * pcb->mss; pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
pcb->flags |= TF_INFR; pcb->flags |= TF_INFR;
} else { } else {
/* Inflate the congestion window, but not if it means that /* Inflate the congestion window, but not if it means that
the value overflows. */ the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss; pcb->cwnd += pcb->mss;
} }
} }
} }
} else { } else {
LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupack averted %lu %lu\n", LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupack averted %lu %lu\n",
pcb->snd_wl1 + pcb->snd_wnd, right_wnd_edge)); pcb->snd_wl1 + pcb->snd_wnd, right_wnd_edge));
} }
} else if (TCP_SEQ_LT(pcb->lastack, ackno) && } else if (TCP_SEQ_LT(pcb->lastack, ackno) &&
TCP_SEQ_LEQ(ackno, pcb->snd_max)) { TCP_SEQ_LEQ(ackno, pcb->snd_max)) {
/* We come here when the ACK acknowledges new data. */ /* We come here when the ACK acknowledges new data. */
/* Reset the "IN Fast Retransmit" flag, since we are no longer /* Reset the "IN Fast Retransmit" flag, since we are no longer
in fast retransmit. Also reset the congestion window to the in fast retransmit. Also reset the congestion window to the
slow start threshold. */ slow start threshold. */
if (pcb->flags & TF_INFR) { if (pcb->flags & TF_INFR) {
pcb->flags &= ~TF_INFR; pcb->flags &= ~TF_INFR;
pcb->cwnd = pcb->ssthresh; pcb->cwnd = pcb->ssthresh;
} }
/* Reset the number of retransmissions. */ /* Reset the number of retransmissions. */
@ -757,86 +762,91 @@ tcp_receive(struct tcp_pcb *pcb)
ssthresh). */ ssthresh). */
if (pcb->state >= ESTABLISHED) { if (pcb->state >= ESTABLISHED) {
if (pcb->cwnd < pcb->ssthresh) { if (pcb->cwnd < pcb->ssthresh) {
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
pcb->cwnd += pcb->mss; pcb->cwnd += pcb->mss;
} }
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %u\n", pcb->cwnd)); LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %u\n", pcb->cwnd));
} else { } else {
u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd); u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
if (new_cwnd > pcb->cwnd) { if (new_cwnd > pcb->cwnd) {
pcb->cwnd = new_cwnd; pcb->cwnd = new_cwnd;
} }
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %u\n", pcb->cwnd)); LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %u\n", pcb->cwnd));
} }
} }
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %lu, unacked->seqno %lu:%lu\n", LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %lu, unacked->seqno %lu:%lu\n",
ackno, ackno,
pcb->unacked != NULL? pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno): 0, ntohl(pcb->unacked->tcphdr->seqno): 0,
pcb->unacked != NULL? pcb->unacked != NULL?
ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0)); ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
/* Remove segment from the unacknowledged list if the incoming /* Remove segment from the unacknowledged list if the incoming
ACK acknowlegdes them. */ ACK acknowlegdes them. */
while (pcb->unacked != NULL && while (pcb->unacked != NULL &&
TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) + TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked), ackno)) { TCP_TCPLEN(pcb->unacked), ackno)) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %lu:%lu from pcb->unacked\n", LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %lu:%lu from pcb->unacked\n",
ntohl(pcb->unacked->tcphdr->seqno), ntohl(pcb->unacked->tcphdr->seqno),
ntohl(pcb->unacked->tcphdr->seqno) + ntohl(pcb->unacked->tcphdr->seqno) +
TCP_TCPLEN(pcb->unacked))); TCP_TCPLEN(pcb->unacked)));
next = pcb->unacked; next = pcb->unacked;
pcb->unacked = pcb->unacked->next; pcb->unacked = pcb->unacked->next;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %u ... ", (unsigned int)pcb->snd_queuelen)); LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %u ... ", (unsigned int)pcb->snd_queuelen));
pcb->snd_queuelen -= pbuf_clen(next->p); pcb->snd_queuelen -= pbuf_clen(next->p);
tcp_seg_free(next); tcp_seg_free(next);
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%u (after freeing unacked)\n", (unsigned int)pcb->snd_queuelen)); LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%u (after freeing unacked)\n", (unsigned int)pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) { if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL || LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL); pcb->unsent != NULL);
} }
} }
pcb->polltmr = 0; pcb->polltmr = 0;
} }
/* We go through the ->unsent list to see if any of the segments /* We go through the ->unsent list to see if any of the segments
on the list are acknowledged by the ACK. This may seem on the list are acknowledged by the ACK. This may seem
strange since an "unsent" segment shouldn't be acked. The strange since an "unsent" segment shouldn't be acked. The
rationale is that lwIP puts all outstanding segments on the rationale is that lwIP puts all outstanding segments on the
->unsent list after a retransmission, so these segments may ->unsent list after a retransmission, so these segments may
in fact have been sent once. */ in fact have been sent once. */
while (pcb->unsent != NULL && /* KJM 13th July 2004
TCP_SEQ_LEQ(ntohl(pcb->unsent->tcphdr->seqno) + TCP_TCPLEN(pcb->unsent), I don't think is is necessary as we no longer move all unacked
ackno) && segments on the unsent queue when performing retransmit */
TCP_SEQ_LEQ(ackno, pcb->snd_max)) { /*
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %lu:%lu from pcb->unsent\n", while (pcb->unsent != NULL &&
ntohl(pcb->unsent->tcphdr->seqno), TCP_SEQ_LEQ(ntohl(pcb->unsent->tcphdr->seqno) + TCP_TCPLEN(pcb->unsent),
ntohl(pcb->unsent->tcphdr->seqno) + ackno) &&
TCP_TCPLEN(pcb->unsent))); TCP_SEQ_LEQ(ackno, pcb->snd_max)) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %lu:%lu from pcb->unsent\n",
ntohl(pcb->unsent->tcphdr->seqno),
ntohl(pcb->unsent->tcphdr->seqno) +
TCP_TCPLEN(pcb->unsent)));
next = pcb->unsent; next = pcb->unsent;
pcb->unsent = pcb->unsent->next; pcb->unsent = pcb->unsent->next;
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %u ... ", (unsigned int)pcb->snd_queuelen)); LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %u ... ", (unsigned int)pcb->snd_queuelen));
pcb->snd_queuelen -= pbuf_clen(next->p); pcb->snd_queuelen -= pbuf_clen(next->p);
tcp_seg_free(next); tcp_seg_free(next);
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%u (after freeing unsent)\n", (unsigned int)pcb->snd_queuelen)); LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%u (after freeing unsent)\n", (unsigned int)pcb->snd_queuelen));
if (pcb->snd_queuelen != 0) { if (pcb->snd_queuelen != 0) {
LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL || LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
pcb->unsent != NULL); pcb->unsent != NULL);
}
if (pcb->unsent != NULL) {
pcb->snd_nxt = htonl(pcb->unsent->tcphdr->seqno);
}
} }
if (pcb->unsent != NULL) {
pcb->snd_nxt = htonl(pcb->unsent->tcphdr->seqno);
}
}
*/
/* End of ACK for new data processing. */ /* End of ACK for new data processing. */
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %u rtseq %lu ackno %lu\n", LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %u rtseq %lu ackno %lu\n",
pcb->rttest, pcb->rtseq, ackno)); pcb->rttest, pcb->rtseq, ackno));
/* RTT estimation calculations. This is done by checking if the /* RTT estimation calculations. This is done by checking if the
incoming segment acknowledges the segment we use to take a incoming segment acknowledges the segment we use to take a
@ -845,20 +855,20 @@ tcp_receive(struct tcp_pcb *pcb)
m = tcp_ticks - pcb->rttest; m = tcp_ticks - pcb->rttest;
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %u ticks (%u msec).\n", LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %u ticks (%u msec).\n",
m, m * TCP_SLOW_INTERVAL)); m, m * TCP_SLOW_INTERVAL));
/* This is taken directly from VJs original code in his paper */ /* This is taken directly from VJs original code in his paper */
m = m - (pcb->sa >> 3); m = m - (pcb->sa >> 3);
pcb->sa += m; pcb->sa += m;
if (m < 0) { if (m < 0) {
m = -m; m = -m;
} }
m = m - (pcb->sv >> 2); m = m - (pcb->sv >> 2);
pcb->sv += m; pcb->sv += m;
pcb->rto = (pcb->sa >> 3) + pcb->sv; pcb->rto = (pcb->sa >> 3) + pcb->sv;
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %u (%u miliseconds)\n", LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %u (%u miliseconds)\n",
pcb->rto, pcb->rto * TCP_SLOW_INTERVAL)); pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
pcb->rttest = 0; pcb->rttest = 0;
} }
@ -869,26 +879,26 @@ tcp_receive(struct tcp_pcb *pcb)
if (tcplen > 0) { if (tcplen > 0) {
/* This code basically does three things: /* This code basically does three things:
+) If the incoming segment contains data that is the next +) If the incoming segment contains data that is the next
in-sequence data, this data is passed to the application. This in-sequence data, this data is passed to the application. This
might involve trimming the first edge of the data. The rcv_nxt might involve trimming the first edge of the data. The rcv_nxt
variable and the advertised window are adjusted. variable and the advertised window are adjusted.
+) If the incoming segment has data that is above the next +) If the incoming segment has data that is above the next
sequence number expected (->rcv_nxt), the segment is placed on sequence number expected (->rcv_nxt), the segment is placed on
the ->ooseq queue. This is done by finding the appropriate the ->ooseq queue. This is done by finding the appropriate
place in the ->ooseq queue (which is ordered by sequence place in the ->ooseq queue (which is ordered by sequence
number) and trim the segment in both ends if needed. An number) and trim the segment in both ends if needed. An
immediate ACK is sent to indicate that we received an immediate ACK is sent to indicate that we received an
out-of-sequence segment. out-of-sequence segment.
+) Finally, we check if the first segment on the ->ooseq queue +) Finally, we check if the first segment on the ->ooseq queue
now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
rcv_nxt > ooseq->seqno, we must trim the first edge of the rcv_nxt > ooseq->seqno, we must trim the first edge of the
segment on ->ooseq before we adjust rcv_nxt. The data in the segment on ->ooseq before we adjust rcv_nxt. The data in the
segments that are now on sequence are chained onto the segments that are now on sequence are chained onto the
incoming segment so that we only need to call the application incoming segment so that we only need to call the application
once. once.
*/ */
/* First, we check if we must trim the first edge. We have to do /* First, we check if we must trim the first edge. We have to do
@ -897,25 +907,25 @@ tcp_receive(struct tcp_pcb *pcb)
segment is larger than rcv_nxt. */ segment is larger than rcv_nxt. */
if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){ if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) { if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {
/* Trimming the first edge is done by pushing the payload /* Trimming the first edge is done by pushing the payload
pointer in the pbuf downwards. This is somewhat tricky since pointer in the pbuf downwards. This is somewhat tricky since
we do not want to discard the full contents of the pbuf up to we do not want to discard the full contents of the pbuf up to
the new starting point of the data since we have to keep the the new starting point of the data since we have to keep the
TCP header which is present in the first pbuf in the chain. TCP header which is present in the first pbuf in the chain.
What is done is really quite a nasty hack: the first pbuf in What is done is really quite a nasty hack: the first pbuf in
the pbuf chain is pointed to by inseg.p. Since we need to be the pbuf chain is pointed to by inseg.p. Since we need to be
able to deallocate the whole pbuf, we cannot change this able to deallocate the whole pbuf, we cannot change this
inseg.p pointer to point to any of the later pbufs in the inseg.p pointer to point to any of the later pbufs in the
chain. Instead, we point the ->payload pointer in the first chain. Instead, we point the ->payload pointer in the first
pbuf to data in one of the later pbufs. We also set the pbuf to data in one of the later pbufs. We also set the
inseg.data pointer to point to the right place. This way, the inseg.data pointer to point to the right place. This way, the
->p pointer will still point to the first pbuf, but the ->p pointer will still point to the first pbuf, but the
->p->payload pointer will point to data in another pbuf. ->p->payload pointer will point to data in another pbuf.
After we are done with adjusting the pbuf pointers we must After we are done with adjusting the pbuf pointers we must
adjust the ->data pointer in the seg and the segment adjust the ->data pointer in the seg and the segment
length.*/ length.*/
off = pcb->rcv_nxt - seqno; off = pcb->rcv_nxt - seqno;
p = inseg.p; p = inseg.p;
@ -941,11 +951,11 @@ tcp_receive(struct tcp_pcb *pcb)
inseg.tcphdr->seqno = seqno = pcb->rcv_nxt; inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
} }
else{ else{
/* the whole segment is < rcv_nxt */ /* the whole segment is < rcv_nxt */
/* must be a duplicate of a packet that has already been correctly handled */ /* must be a duplicate of a packet that has already been correctly handled */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %lu\n", seqno)); LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %lu\n", seqno));
tcp_ack_now(pcb); tcp_ack_now(pcb);
} }
} }
@ -953,204 +963,204 @@ tcp_receive(struct tcp_pcb *pcb)
and below rcv_nxt + rcv_wnd) in order to be further and below rcv_nxt + rcv_wnd) in order to be further
processed. */ processed. */
if (TCP_SEQ_GEQ(seqno, pcb->rcv_nxt) && if (TCP_SEQ_GEQ(seqno, pcb->rcv_nxt) &&
TCP_SEQ_LT(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) { TCP_SEQ_LT(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {
if (pcb->rcv_nxt == seqno) { if (pcb->rcv_nxt == seqno) {
/* The incoming segment is the next in sequence. We check if /* The incoming segment is the next in sequence. We check if
we have to trim the end of the segment and update rcv_nxt we have to trim the end of the segment and update rcv_nxt
and pass the data to the application. */ and pass the data to the application. */
#if TCP_QUEUE_OOSEQ #if TCP_QUEUE_OOSEQ
if (pcb->ooseq != NULL && if (pcb->ooseq != NULL &&
TCP_SEQ_LEQ(pcb->ooseq->tcphdr->seqno, seqno + inseg.len)) { TCP_SEQ_LEQ(pcb->ooseq->tcphdr->seqno, seqno + inseg.len)) {
/* We have to trim the second edge of the incoming /* We have to trim the second edge of the incoming
segment. */ segment. */
inseg.len = pcb->ooseq->tcphdr->seqno - seqno; inseg.len = pcb->ooseq->tcphdr->seqno - seqno;
pbuf_realloc(inseg.p, inseg.len); pbuf_realloc(inseg.p, inseg.len);
} }
#endif /* TCP_QUEUE_OOSEQ */ #endif /* TCP_QUEUE_OOSEQ */
tcplen = TCP_TCPLEN(&inseg); tcplen = TCP_TCPLEN(&inseg);
pcb->rcv_nxt += tcplen; pcb->rcv_nxt += tcplen;
/* Update the receiver's (our) window. */ /* Update the receiver's (our) window. */
if (pcb->rcv_wnd < tcplen) { if (pcb->rcv_wnd < tcplen) {
pcb->rcv_wnd = 0; pcb->rcv_wnd = 0;
} else { } else {
pcb->rcv_wnd -= tcplen; pcb->rcv_wnd -= tcplen;
} }
/* If there is data in the segment, we make preparations to /* If there is data in the segment, we make preparations to
pass this up to the application. The ->recv_data variable pass this up to the application. The ->recv_data variable
is used for holding the pbuf that goes to the is used for holding the pbuf that goes to the
application. The code for reassembling out-of-sequence data application. The code for reassembling out-of-sequence data
chains its data on this pbuf as well. chains its data on this pbuf as well.
If the segment was a FIN, we set the TF_GOT_FIN flag that will If the segment was a FIN, we set the TF_GOT_FIN flag that will
be used to indicate to the application that the remote side has be used to indicate to the application that the remote side has
closed its end of the connection. */ closed its end of the connection. */
if (inseg.p->tot_len > 0) { if (inseg.p->tot_len > 0) {
recv_data = inseg.p; recv_data = inseg.p;
/* Since this pbuf now is the responsibility of the /* Since this pbuf now is the responsibility of the
application, we delete our reference to it so that we won't application, we delete our reference to it so that we won't
(mistakingly) deallocate it. */ (mistakingly) deallocate it. */
inseg.p = NULL; inseg.p = NULL;
} }
if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) { if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n")); LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
recv_flags = TF_GOT_FIN; recv_flags = TF_GOT_FIN;
} }
#if TCP_QUEUE_OOSEQ #if TCP_QUEUE_OOSEQ
/* We now check if we have segments on the ->ooseq queue that /* We now check if we have segments on the ->ooseq queue that
is now in sequence. */ is now in sequence. */
while (pcb->ooseq != NULL && while (pcb->ooseq != NULL &&
pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) { pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
cseg = pcb->ooseq; cseg = pcb->ooseq;
seqno = pcb->ooseq->tcphdr->seqno; seqno = pcb->ooseq->tcphdr->seqno;
pcb->rcv_nxt += TCP_TCPLEN(cseg); pcb->rcv_nxt += TCP_TCPLEN(cseg);
if (pcb->rcv_wnd < TCP_TCPLEN(cseg)) { if (pcb->rcv_wnd < TCP_TCPLEN(cseg)) {
pcb->rcv_wnd = 0; pcb->rcv_wnd = 0;
} else { } else {
pcb->rcv_wnd -= TCP_TCPLEN(cseg); pcb->rcv_wnd -= TCP_TCPLEN(cseg);
} }
if (cseg->p->tot_len > 0) { if (cseg->p->tot_len > 0) {
/* Chain this pbuf onto the pbuf that we will pass to /* Chain this pbuf onto the pbuf that we will pass to
the application. */ the application. */
if (recv_data) { if (recv_data) {
pbuf_cat(recv_data, cseg->p); pbuf_cat(recv_data, cseg->p);
} else { } else {
recv_data = cseg->p; recv_data = cseg->p;
} }
cseg->p = NULL; cseg->p = NULL;
} }
if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) { if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n")); LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
recv_flags = TF_GOT_FIN; recv_flags = TF_GOT_FIN;
} }
pcb->ooseq = cseg->next; pcb->ooseq = cseg->next;
tcp_seg_free(cseg); tcp_seg_free(cseg);
} }
#endif /* TCP_QUEUE_OOSEQ */ #endif /* TCP_QUEUE_OOSEQ */
/* Acknowledge the segment(s). */ /* Acknowledge the segment(s). */
tcp_ack(pcb); tcp_ack(pcb);
} else { } else {
/* We get here if the incoming segment is out-of-sequence. */ /* We get here if the incoming segment is out-of-sequence. */
tcp_ack_now(pcb); tcp_ack_now(pcb);
#if TCP_QUEUE_OOSEQ #if TCP_QUEUE_OOSEQ
/* We queue the segment on the ->ooseq queue. */ /* We queue the segment on the ->ooseq queue. */
if (pcb->ooseq == NULL) { if (pcb->ooseq == NULL) {
pcb->ooseq = tcp_seg_copy(&inseg); pcb->ooseq = tcp_seg_copy(&inseg);
} else { } else {
/* If the queue is not empty, we walk through the queue and /* If the queue is not empty, we walk through the queue and
try to find a place where the sequence number of the try to find a place where the sequence number of the
incoming segment is between the sequence numbers of the incoming segment is between the sequence numbers of the
previous and the next segment on the ->ooseq queue. That is previous and the next segment on the ->ooseq queue. That is
the place where we put the incoming segment. If needed, we the place where we put the incoming segment. If needed, we
trim the second edges of the previous and the incoming trim the second edges of the previous and the incoming
segment so that it will fit into the sequence. segment so that it will fit into the sequence.
If the incoming segment has the same sequence number as a If the incoming segment has the same sequence number as a
segment on the ->ooseq queue, we discard the segment that segment on the ->ooseq queue, we discard the segment that
contains less data. */ contains less data. */
prev = NULL; prev = NULL;
for(next = pcb->ooseq; next != NULL; next = next->next) { for(next = pcb->ooseq; next != NULL; next = next->next) {
if (seqno == next->tcphdr->seqno) { if (seqno == next->tcphdr->seqno) {
/* The sequence number of the incoming segment is the /* The sequence number of the incoming segment is the
same as the sequence number of the segment on same as the sequence number of the segment on
->ooseq. We check the lengths to see which one to ->ooseq. We check the lengths to see which one to
discard. */ discard. */
if (inseg.len > next->len) { if (inseg.len > next->len) {
/* The incoming segment is larger than the old /* The incoming segment is larger than the old
segment. We replace the old segment with the new segment. We replace the old segment with the new
one. */ one. */
cseg = tcp_seg_copy(&inseg); cseg = tcp_seg_copy(&inseg);
if (cseg != NULL) { if (cseg != NULL) {
cseg->next = next->next; cseg->next = next->next;
if (prev != NULL) { if (prev != NULL) {
prev->next = cseg; prev->next = cseg;
} else { } else {
pcb->ooseq = cseg; pcb->ooseq = cseg;
} }
} }
break; break;
} else { } else {
/* Either the lenghts are the same or the incoming /* Either the lenghts are the same or the incoming
segment was smaller than the old one; in either segment was smaller than the old one; in either
case, we ditch the incoming segment. */ case, we ditch the incoming segment. */
break; break;
} }
} else { } else {
if (prev == NULL) { if (prev == NULL) {
if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) { if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
/* The sequence number of the incoming segment is lower /* The sequence number of the incoming segment is lower
than the sequence number of the first segment on the than the sequence number of the first segment on the
queue. We put the incoming segment first on the queue. We put the incoming segment first on the
queue. */ queue. */
if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) { if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) {
/* We need to trim the incoming segment. */ /* We need to trim the incoming segment. */
inseg.len = next->tcphdr->seqno - seqno; inseg.len = next->tcphdr->seqno - seqno;
pbuf_realloc(inseg.p, inseg.len); pbuf_realloc(inseg.p, inseg.len);
} }
cseg = tcp_seg_copy(&inseg); cseg = tcp_seg_copy(&inseg);
if (cseg != NULL) { if (cseg != NULL) {
cseg->next = next; cseg->next = next;
pcb->ooseq = cseg; pcb->ooseq = cseg;
} }
break; break;
} }
} else if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) && } else if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
TCP_SEQ_LT(seqno, next->tcphdr->seqno)) { TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
/* The sequence number of the incoming segment is in /* The sequence number of the incoming segment is in
between the sequence numbers of the previous and between the sequence numbers of the previous and
the next segment on ->ooseq. We trim and insert the the next segment on ->ooseq. We trim and insert the
incoming segment and trim the previous segment, if incoming segment and trim the previous segment, if
needed. */ needed. */
if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) { if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) {
/* We need to trim the incoming segment. */ /* We need to trim the incoming segment. */
inseg.len = next->tcphdr->seqno - seqno; inseg.len = next->tcphdr->seqno - seqno;
pbuf_realloc(inseg.p, inseg.len); pbuf_realloc(inseg.p, inseg.len);
} }
cseg = tcp_seg_copy(&inseg); cseg = tcp_seg_copy(&inseg);
if (cseg != NULL) { if (cseg != NULL) {
cseg->next = next; cseg->next = next;
prev->next = cseg; prev->next = cseg;
if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) { if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
/* We need to trim the prev segment. */ /* We need to trim the prev segment. */
prev->len = seqno - prev->tcphdr->seqno; prev->len = seqno - prev->tcphdr->seqno;
pbuf_realloc(prev->p, prev->len); pbuf_realloc(prev->p, prev->len);
} }
} }
break; break;
} }
/* If the "next" segment is the last segment on the /* If the "next" segment is the last segment on the
ooseq queue, we add the incoming segment to the end ooseq queue, we add the incoming segment to the end
of the list. */ of the list. */
if (next->next == NULL && if (next->next == NULL &&
TCP_SEQ_GT(seqno, next->tcphdr->seqno)) { TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
next->next = tcp_seg_copy(&inseg); next->next = tcp_seg_copy(&inseg);
if (next->next != NULL) { if (next->next != NULL) {
if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) { if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
/* We need to trim the last segment. */ /* We need to trim the last segment. */
next->len = seqno - next->tcphdr->seqno; next->len = seqno - next->tcphdr->seqno;
pbuf_realloc(next->p, next->len); pbuf_realloc(next->p, next->len);
} }
} }
break; break;
}
}
prev = next;
}
} }
}
prev = next;
}
}
#endif /* TCP_QUEUE_OOSEQ */ #endif /* TCP_QUEUE_OOSEQ */
} }
@ -1159,7 +1169,7 @@ tcp_receive(struct tcp_pcb *pcb)
/* Segments with length 0 is taken care of here. Segments that /* Segments with length 0 is taken care of here. Segments that
fall out of the window are ACKed. */ fall out of the window are ACKed. */
if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) || if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) ||
TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) { TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {
tcp_ack_now(pcb); tcp_ack_now(pcb);
} }
} }