/** | |
* @file | |
* | |
* Transmission Control Protocol, outgoing traffic | |
* | |
* The output functions of TCP. | |
* | |
*/ | |
/* | |
* Copyright (c) 2001-2004 Swedish Institute of Computer Science. | |
* All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without modification, | |
* are permitted provided that the following conditions are met: | |
* | |
* 1. Redistributions of source code must retain the above copyright notice, | |
* this list of conditions and the following disclaimer. | |
* 2. Redistributions in binary form must reproduce the above copyright notice, | |
* this list of conditions and the following disclaimer in the documentation | |
* and/or other materials provided with the distribution. | |
* 3. The name of the author may not be used to endorse or promote products | |
* derived from this software without specific prior written permission. | |
* | |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT | |
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT | |
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING | |
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY | |
* OF SUCH DAMAGE. | |
* | |
* This file is part of the lwIP TCP/IP stack. | |
* | |
* Author: Adam Dunkels <adam@sics.se> | |
* | |
*/ | |
#include <string.h> | |
#include "lwip/def.h" | |
#include "lwip/opt.h" | |
#include "lwip/mem.h" | |
#include "lwip/memp.h" | |
#include "lwip/sys.h" | |
#include "lwip/ip_addr.h" | |
#include "lwip/netif.h" | |
#include "lwip/inet.h" | |
#include "lwip/tcp.h" | |
#include "lwip/stats.h" | |
#include "lwip/snmp.h" | |
#if LWIP_TCP | |
/* Forward declarations.*/ | |
static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb); | |
err_t | |
tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags) | |
{ | |
/* no data, no length, flags, copy=1, no optdata, no optdatalen */ | |
return tcp_enqueue(pcb, NULL, 0, flags, 1, NULL, 0); | |
} | |
/** | |
* Write data for sending (but does not send it immediately). | |
* | |
* It waits in the expectation of more data being sent soon (as | |
* it can send them more efficiently by combining them together). | |
* To prompt the system to send data now, call tcp_output() after | |
* calling tcp_write(). | |
* | |
* @arg pcb Protocol control block of the TCP connection to enqueue data for. | |
* | |
* @see tcp_write() | |
*/ | |
err_t | |
tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t copy) | |
{ | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, arg=%p, len=%"U16_F", copy=%"U16_F")\n", (void *)pcb, | |
arg, len, (u16_t)copy)); | |
/* connection is in valid state for data transmission? */ | |
if (pcb->state == ESTABLISHED || | |
pcb->state == CLOSE_WAIT || | |
pcb->state == SYN_SENT || | |
pcb->state == SYN_RCVD) { | |
if (len > 0) { | |
return tcp_enqueue(pcb, (void *)arg, len, 0, copy, NULL, 0); | |
} | |
return ERR_OK; | |
} else { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_STATE | 3, ("tcp_write() called in invalid state\n")); | |
return ERR_CONN; | |
} | |
} | |
/** | |
* Enqueue either data or TCP options (but not both) for tranmission | |
* | |
* | |
* | |
* @arg pcb Protocol control block for the TCP connection to enqueue data for. | |
* @arg arg Pointer to the data to be enqueued for sending. | |
* @arg len Data length in bytes | |
* @arg flags | |
* @arg copy 1 if data must be copied, 0 if data is non-volatile and can be | |
* referenced. | |
* @arg optdata | |
* @arg optlen | |
*/ | |
err_t | |
tcp_enqueue(struct tcp_pcb *pcb, void *arg, u16_t len, | |
u8_t flags, u8_t copy, | |
u8_t *optdata, u8_t optlen) | |
{ | |
struct pbuf *p; | |
struct tcp_seg *seg, *useg, *queue; | |
u32_t left, seqno; | |
u16_t seglen; | |
void *ptr; | |
u8_t queuelen; | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_enqueue(pcb=%p, arg=%p, len=%"U16_F", flags=%"X16_F", copy=%"U16_F")\n", | |
(void *)pcb, arg, len, (u16_t)flags, (u16_t)copy)); | |
LWIP_ASSERT("tcp_enqueue: len == 0 || optlen == 0 (programmer violates API)", | |
len == 0 || optlen == 0); | |
LWIP_ASSERT("tcp_enqueue: arg == NULL || optdata == NULL (programmer violates API)", | |
arg == NULL || optdata == NULL); | |
/* fail on too much data */ | |
if (len > pcb->snd_buf) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n", len, pcb->snd_buf)); | |
return ERR_MEM; | |
} | |
left = len; | |
ptr = arg; | |
/* seqno will be the sequence number of the first segment enqueued | |
* by the call to this function. */ | |
seqno = pcb->snd_lbb; | |
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen)); | |
/* If total number of pbufs on the unsent/unacked queues exceeds the | |
* configured maximum, return an error */ | |
queuelen = pcb->snd_queuelen; | |
if (queuelen >= TCP_SND_QUEUELEN) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue: too long queue %"U16_F" (max %"U16_F")\n", queuelen, TCP_SND_QUEUELEN)); | |
TCP_STATS_INC(tcp.memerr); | |
return ERR_MEM; | |
} | |
if (queuelen != 0) { | |
LWIP_ASSERT("tcp_enqueue: pbufs on queue => at least one queue non-empty", | |
pcb->unacked != NULL || pcb->unsent != NULL); | |
} else { | |
LWIP_ASSERT("tcp_enqueue: no pbufs on queue => both queues empty", | |
pcb->unacked == NULL && pcb->unsent == NULL); | |
} | |
/* First, break up the data into segments and tuck them together in | |
* the local "queue" variable. */ | |
useg = queue = seg = NULL; | |
seglen = 0; | |
while (queue == NULL || left > 0) { | |
/* The segment length should be the MSS if the data to be enqueued | |
* is larger than the MSS. */ | |
seglen = left > pcb->mss? pcb->mss: left; | |
/* Allocate memory for tcp_seg, and fill in fields. */ | |
seg = memp_malloc(MEMP_TCP_SEG); | |
if (seg == NULL) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for tcp_seg\n")); | |
goto memerr; | |
} | |
seg->next = NULL; | |
seg->p = NULL; | |
/* first segment of to-be-queued data? */ | |
if (queue == NULL) { | |
queue = seg; | |
} | |
/* subsequent segments of to-be-queued data */ | |
else { | |
/* Attach the segment to the end of the queued segments */ | |
LWIP_ASSERT("useg != NULL", useg != NULL); | |
useg->next = seg; | |
} | |
/* remember last segment of to-be-queued data for next iteration */ | |
useg = seg; | |
/* If copy is set, memory should be allocated | |
* and data copied into pbuf, otherwise data comes from | |
* ROM or other static memory, and need not be copied. If | |
* optdata is != NULL, we have options instead of data. */ | |
/* options? */ | |
if (optdata != NULL) { | |
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) { | |
goto memerr; | |
} | |
++queuelen; | |
seg->dataptr = seg->p->payload; | |
} | |
/* copy from volatile memory? */ | |
else if (copy) { | |
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_RAM)) == NULL) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue : could not allocate memory for pbuf copy size %"U16_F"\n", seglen)); | |
goto memerr; | |
} | |
++queuelen; | |
if (arg != NULL) { | |
memcpy(seg->p->payload, ptr, seglen); | |
} | |
seg->dataptr = seg->p->payload; | |
} | |
/* do not copy data */ | |
else { | |
/* First, allocate a pbuf for holding the data. | |
* since the referenced data is available at least until it is sent out on the | |
* link (as it has to be ACKed by the remote party) we can safely use PBUF_ROM | |
* instead of PBUF_REF here. | |
*/ | |
if ((p = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for zero-copy pbuf\n")); | |
goto memerr; | |
} | |
++queuelen; | |
/* reference the non-volatile payload data */ | |
p->payload = ptr; | |
seg->dataptr = ptr; | |
/* Second, allocate a pbuf for the headers. */ | |
if ((seg->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_RAM)) == NULL) { | |
/* If allocation fails, we have to deallocate the data pbuf as | |
* well. */ | |
pbuf_free(p); | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: could not allocate memory for header pbuf\n")); | |
goto memerr; | |
} | |
++queuelen; | |
/* Concatenate the headers and data pbufs together. */ | |
pbuf_cat(seg->p/*header*/, p/*data*/); | |
p = NULL; | |
} | |
/* Now that there are more segments queued, we check again if the | |
length of the queue exceeds the configured maximum. */ | |
if (queuelen > TCP_SND_QUEUELEN) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN)); | |
goto memerr; | |
} | |
seg->len = seglen; | |
/* build TCP header */ | |
if (pbuf_header(seg->p, TCP_HLEN)) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_enqueue: no room for TCP header in pbuf.\n")); | |
TCP_STATS_INC(tcp.err); | |
goto memerr; | |
} | |
seg->tcphdr = seg->p->payload; | |
seg->tcphdr->src = htons(pcb->local_port); | |
seg->tcphdr->dest = htons(pcb->remote_port); | |
seg->tcphdr->seqno = htonl(seqno); | |
seg->tcphdr->urgp = 0; | |
TCPH_FLAGS_SET(seg->tcphdr, flags); | |
/* don't fill in tcphdr->ackno and tcphdr->wnd until later */ | |
/* Copy the options into the header, if they are present. */ | |
if (optdata == NULL) { | |
TCPH_HDRLEN_SET(seg->tcphdr, 5); | |
} | |
else { | |
TCPH_HDRLEN_SET(seg->tcphdr, (5 + optlen / 4)); | |
/* Copy options into data portion of segment. | |
Options can thus only be sent in non data carrying | |
segments such as SYN|ACK. */ | |
memcpy(seg->dataptr, optdata, optlen); | |
} | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE, ("tcp_enqueue: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n", | |
ntohl(seg->tcphdr->seqno), | |
ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg), | |
(u16_t)flags)); | |
left -= seglen; | |
seqno += seglen; | |
ptr = (void *)((u8_t *)ptr + seglen); | |
} | |
/* Now that the data to be enqueued has been broken up into TCP | |
segments in the queue variable, we add them to the end of the | |
pcb->unsent queue. */ | |
if (pcb->unsent == NULL) { | |
useg = NULL; | |
} | |
else { | |
for (useg = pcb->unsent; useg->next != NULL; useg = useg->next); | |
} | |
/* { useg is last segment on the unsent queue, NULL if list is empty } */ | |
/* If there is room in the last pbuf on the unsent queue, | |
chain the first pbuf on the queue together with that. */ | |
if (useg != NULL && | |
TCP_TCPLEN(useg) != 0 && | |
!(TCPH_FLAGS(useg->tcphdr) & (TCP_SYN | TCP_FIN)) && | |
!(flags & (TCP_SYN | TCP_FIN)) && | |
/* fit within max seg size */ | |
useg->len + queue->len <= pcb->mss) { | |
/* Remove TCP header from first segment of our to-be-queued list */ | |
pbuf_header(queue->p, -TCP_HLEN); | |
pbuf_cat(useg->p, queue->p); | |
useg->len += queue->len; | |
useg->next = queue->next; | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | DBG_TRACE | DBG_STATE, ("tcp_enqueue: chaining segments, new len %"U16_F"\n", useg->len)); | |
if (seg == queue) { | |
seg = NULL; | |
} | |
memp_free(MEMP_TCP_SEG, queue); | |
} | |
else { | |
/* empty list */ | |
if (useg == NULL) { | |
/* initialize list with this segment */ | |
pcb->unsent = queue; | |
} | |
/* enqueue segment */ | |
else { | |
useg->next = queue; | |
} | |
} | |
if ((flags & TCP_SYN) || (flags & TCP_FIN)) { | |
++len; | |
} | |
pcb->snd_lbb += len; | |
pcb->snd_buf -= len; | |
/* update number of segments on the queues */ | |
pcb->snd_queuelen = queuelen; | |
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: %"S16_F" (after enqueued)\n", pcb->snd_queuelen)); | |
if (pcb->snd_queuelen != 0) { | |
LWIP_ASSERT("tcp_enqueue: valid queue length", | |
pcb->unacked != NULL || pcb->unsent != NULL); | |
} | |
/* Set the PSH flag in the last segment that we enqueued, but only | |
if the segment has data (indicated by seglen > 0). */ | |
if (seg != NULL && seglen > 0 && seg->tcphdr != NULL) { | |
TCPH_SET_FLAG(seg->tcphdr, TCP_PSH); | |
} | |
return ERR_OK; | |
memerr: | |
TCP_STATS_INC(tcp.memerr); | |
if (queue != NULL) { | |
tcp_segs_free(queue); | |
} | |
if (pcb->snd_queuelen != 0) { | |
LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL || | |
pcb->unsent != NULL); | |
} | |
LWIP_DEBUGF(TCP_QLEN_DEBUG | DBG_STATE, ("tcp_enqueue: %"S16_F" (with mem err)\n", pcb->snd_queuelen)); | |
return ERR_MEM; | |
} | |
/* find out what we can send and send it */ | |
err_t | |
tcp_output(struct tcp_pcb *pcb) | |
{ | |
struct pbuf *p; | |
struct tcp_hdr *tcphdr; | |
struct tcp_seg *seg, *useg; | |
u32_t wnd; | |
#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; | |
/* 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)) { | |
p = pbuf_alloc(PBUF_IP, TCP_HLEN, 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 = p->payload; | |
tcphdr->src = htons(pcb->local_port); | |
tcphdr->dest = htons(pcb->remote_port); | |
tcphdr->seqno = htonl(pcb->snd_nxt); | |
tcphdr->ackno = htonl(pcb->rcv_nxt); | |
TCPH_FLAGS_SET(tcphdr, TCP_ACK); | |
tcphdr->wnd = htons(pcb->rcv_wnd); | |
tcphdr->urgp = 0; | |
TCPH_HDRLEN_SET(tcphdr, 5); | |
tcphdr->chksum = 0; | |
#if CHECKSUM_GEN_TCP | |
tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip), | |
IP_PROTO_TCP, p->tot_len); | |
#endif | |
ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos, | |
IP_PROTO_TCP); | |
pbuf_free(p); | |
return ERR_OK; | |
} | |
#if TCP_OUTPUT_DEBUG | |
if (seg == NULL) { | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n", (void*)pcb->unsent)); | |
} | |
#endif /* TCP_OUTPUT_DEBUG */ | |
#if TCP_CWND_DEBUG | |
if (seg == NULL) { | |
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", seg == NULL, ack %"U32_F"\n", | |
pcb->snd_wnd, pcb->cwnd, wnd, | |
pcb->lastack)); | |
} else { | |
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n", | |
pcb->snd_wnd, pcb->cwnd, wnd, | |
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len, | |
ntohl(seg->tcphdr->seqno), pcb->lastack)); | |
} | |
#endif /* TCP_CWND_DEBUG */ | |
/* data available and window allows it to be sent? */ | |
while (seg != NULL && | |
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) { | |
#if TCP_CWND_DEBUG | |
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U32_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\n", | |
pcb->snd_wnd, pcb->cwnd, wnd, | |
ntohl(seg->tcphdr->seqno) + seg->len - | |
pcb->lastack, | |
ntohl(seg->tcphdr->seqno), pcb->lastack, i)); | |
++i; | |
#endif /* TCP_CWND_DEBUG */ | |
pcb->unsent = seg->next; | |
if (pcb->state != SYN_SENT) { | |
TCPH_SET_FLAG(seg->tcphdr, TCP_ACK); | |
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW); | |
} | |
tcp_output_segment(seg, pcb); | |
pcb->snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg); | |
if (TCP_SEQ_LT(pcb->snd_max, pcb->snd_nxt)) { | |
pcb->snd_max = pcb->snd_nxt; | |
} | |
/* put segment on unacknowledged list if length > 0 */ | |
if (TCP_TCPLEN(seg) > 0) { | |
seg->next = NULL; | |
/* unacked list is empty? */ | |
if (pcb->unacked == NULL) { | |
pcb->unacked = seg; | |
useg = seg; | |
/* unacked list is not empty? */ | |
} else { | |
/* In the case of fast retransmit, the packet should not go to the tail | |
* of the unacked queue, but rather at the head. We need to check for | |
* this case. -STJ Jul 27, 2004 */ | |
if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))){ | |
/* add segment to head of unacked list */ | |
seg->next = pcb->unacked; | |
pcb->unacked = seg; | |
} else { | |
/* add segment to tail of unacked list */ | |
useg->next = seg; | |
useg = useg->next; | |
} | |
} | |
/* do not queue empty segments on the unacked list */ | |
} else { | |
tcp_seg_free(seg); | |
} | |
seg = pcb->unsent; | |
} | |
return ERR_OK; | |
} | |
/** | |
* Actually send a TCP segment over IP | |
*/ | |
static void | |
tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb) | |
{ | |
u16_t len; | |
struct netif *netif; | |
/** @bug Exclude retransmitted segments from this count. */ | |
snmp_inc_tcpoutsegs(); | |
/* The TCP header has already been constructed, but the ackno and | |
wnd fields remain. */ | |
seg->tcphdr->ackno = htonl(pcb->rcv_nxt); | |
/* silly window avoidance */ | |
if (pcb->rcv_wnd < pcb->mss) { | |
seg->tcphdr->wnd = 0; | |
} else { | |
/* advertise our receive window size in this TCP segment */ | |
seg->tcphdr->wnd = htons(pcb->rcv_wnd); | |
} | |
/* If we don't have a local IP address, we get one by | |
calling ip_route(). */ | |
if (ip_addr_isany(&(pcb->local_ip))) { | |
netif = ip_route(&(pcb->remote_ip)); | |
if (netif == NULL) { | |
return; | |
} | |
ip_addr_set(&(pcb->local_ip), &(netif->ip_addr)); | |
} | |
pcb->rtime = 0; | |
if (pcb->rttest == 0) { | |
pcb->rttest = tcp_ticks; | |
pcb->rtseq = ntohl(seg->tcphdr->seqno); | |
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq)); | |
} | |
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n", | |
htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) + | |
seg->len)); | |
len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload); | |
seg->p->len -= len; | |
seg->p->tot_len -= len; | |
seg->p->payload = seg->tcphdr; | |
seg->tcphdr->chksum = 0; | |
#if CHECKSUM_GEN_TCP | |
seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, | |
&(pcb->local_ip), | |
&(pcb->remote_ip), | |
IP_PROTO_TCP, seg->p->tot_len); | |
#endif | |
TCP_STATS_INC(tcp.xmit); | |
ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos, | |
IP_PROTO_TCP); | |
} | |
void | |
tcp_rst(u32_t seqno, u32_t ackno, | |
struct ip_addr *local_ip, struct ip_addr *remote_ip, | |
u16_t local_port, u16_t remote_port) | |
{ | |
struct pbuf *p; | |
struct tcp_hdr *tcphdr; | |
p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM); | |
if (p == NULL) { | |
LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n")); | |
return; | |
} | |
tcphdr = p->payload; | |
tcphdr->src = htons(local_port); | |
tcphdr->dest = htons(remote_port); | |
tcphdr->seqno = htonl(seqno); | |
tcphdr->ackno = htonl(ackno); | |
TCPH_FLAGS_SET(tcphdr, TCP_RST | TCP_ACK); | |
tcphdr->wnd = htons(TCP_WND); | |
tcphdr->urgp = 0; | |
TCPH_HDRLEN_SET(tcphdr, 5); | |
tcphdr->chksum = 0; | |
#if CHECKSUM_GEN_TCP | |
tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip, | |
IP_PROTO_TCP, p->tot_len); | |
#endif | |
TCP_STATS_INC(tcp.xmit); | |
snmp_inc_tcpoutrsts(); | |
/* Send output with hardcoded TTL since we have no access to the pcb */ | |
ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP); | |
pbuf_free(p); | |
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno)); | |
} | |
/* requeue all unacked segments for retransmission */ | |
void | |
tcp_rexmit_rto(struct tcp_pcb *pcb) | |
{ | |
struct tcp_seg *seg; | |
if (pcb->unacked == NULL) { | |
return; | |
} | |
/* Move all unacked segments to the head of the unsent queue */ | |
for (seg = pcb->unacked; seg->next != NULL; seg = seg->next); | |
/* concatenate unsent queue after unacked queue */ | |
seg->next = pcb->unsent; | |
/* unsent queue is the concatenated queue (of unacked, unsent) */ | |
pcb->unsent = pcb->unacked; | |
/* unacked queue is now empty */ | |
pcb->unacked = NULL; | |
pcb->snd_nxt = ntohl(pcb->unsent->tcphdr->seqno); | |
/* increment number of retransmissions */ | |
++pcb->nrtx; | |
/* Don't take any RTT measurements after retransmitting. */ | |
pcb->rttest = 0; | |
/* Do the actual retransmission */ | |
tcp_output(pcb); | |
} | |
void | |
tcp_rexmit(struct tcp_pcb *pcb) | |
{ | |
struct tcp_seg *seg; | |
if (pcb->unacked == NULL) { | |
return; | |
} | |
/* Move the first unacked segment to the unsent queue */ | |
seg = pcb->unacked->next; | |
pcb->unacked->next = pcb->unsent; | |
pcb->unsent = pcb->unacked; | |
pcb->unacked = seg; | |
pcb->snd_nxt = ntohl(pcb->unsent->tcphdr->seqno); | |
++pcb->nrtx; | |
/* Don't take any rtt measurements after retransmitting. */ | |
pcb->rttest = 0; | |
/* Do the actual retransmission. */ | |
snmp_inc_tcpretranssegs(); | |
tcp_output(pcb); | |
} | |
void | |
tcp_keepalive(struct tcp_pcb *pcb) | |
{ | |
struct pbuf *p; | |
struct tcp_hdr *tcphdr; | |
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", | |
ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip), | |
ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip))); | |
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt %"U16_F"\n", tcp_ticks, pcb->tmr, pcb->keep_cnt)); | |
p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM); | |
if(p == NULL) { | |
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: could not allocate memory for pbuf\n")); | |
return; | |
} | |
tcphdr = p->payload; | |
tcphdr->src = htons(pcb->local_port); | |
tcphdr->dest = htons(pcb->remote_port); | |
tcphdr->seqno = htonl(pcb->snd_nxt - 1); | |
tcphdr->ackno = htonl(pcb->rcv_nxt); | |
tcphdr->wnd = htons(pcb->rcv_wnd); | |
tcphdr->urgp = 0; | |
TCPH_HDRLEN_SET(tcphdr, 5); | |
tcphdr->chksum = 0; | |
#if CHECKSUM_GEN_TCP | |
tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip, IP_PROTO_TCP, p->tot_len); | |
#endif | |
TCP_STATS_INC(tcp.xmit); | |
/* Send output to IP */ | |
ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP); | |
pbuf_free(p); | |
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n", pcb->snd_nxt - 1, pcb->rcv_nxt)); | |
} | |
#endif /* LWIP_TCP */ | |