+++ /dev/null
-/**
- * @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 "lwip/opt.h"
-
-#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
-
-#include "lwip/tcp_impl.h"
-#include "lwip/def.h"
-#include "lwip/mem.h"
-#include "lwip/memp.h"
-#include "lwip/ip_addr.h"
-#include "lwip/netif.h"
-#include "lwip/inet_chksum.h"
-#include "lwip/stats.h"
-#include "lwip/snmp.h"
-#if LWIP_TCP_TIMESTAMPS
-#include "lwip/sys.h"
-#endif
-
-#include <string.h>
-
-/* Define some copy-macros for checksum-on-copy so that the code looks
- nicer by preventing too many ifdef's. */
-#if TCP_CHECKSUM_ON_COPY
-#define TCP_DATA_COPY(dst, src, len, seg) do { \
- tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
- len, &seg->chksum, &seg->chksum_swapped); \
- seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
-#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
- tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
-#else /* TCP_CHECKSUM_ON_COPY*/
-#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
-#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
-#endif /* TCP_CHECKSUM_ON_COPY*/
-
-/** Define this to 1 for an extra check that the output checksum is valid
- * (usefule when the checksum is generated by the application, not the stack) */
-#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
-#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
-#endif
-
-/* Forward declarations.*/
-static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb);
-
-/** Allocate a pbuf and create a tcphdr at p->payload, used for output
- * functions other than the default tcp_output -> tcp_output_segment
- * (e.g. tcp_send_empty_ack, etc.)
- *
- * @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
- * @param optlen length of header-options
- * @param datalen length of tcp data to reserve in pbuf
- * @param seqno_be seqno in network byte order (big-endian)
- * @return pbuf with p->payload being the tcp_hdr
- */
-static struct pbuf *
-tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
- u32_t seqno_be /* already in network byte order */)
-{
- struct tcp_hdr *tcphdr;
- struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
- if (p != NULL) {
- LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
- (p->len >= TCP_HLEN + optlen));
- tcphdr = (struct tcp_hdr *)p->payload;
- tcphdr->src = htons(pcb->local_port);
- tcphdr->dest = htons(pcb->remote_port);
- tcphdr->seqno = seqno_be;
- tcphdr->ackno = htonl(pcb->rcv_nxt);
- TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
- tcphdr->wnd = htons(pcb->rcv_ann_wnd);
- tcphdr->chksum = 0;
- tcphdr->urgp = 0;
-
- /* If we're sending a packet, update the announced right window edge */
- pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
- }
- return p;
-}
-
-/**
- * Called by tcp_close() to send a segment including FIN flag but not data.
- *
- * @param pcb the tcp_pcb over which to send a segment
- * @return ERR_OK if sent, another err_t otherwise
- */
-err_t
-tcp_send_fin(struct tcp_pcb *pcb)
-{
- /* first, try to add the fin to the last unsent segment */
- if (pcb->unsent != NULL) {
- struct tcp_seg *last_unsent;
- for (last_unsent = pcb->unsent; last_unsent->next != NULL;
- last_unsent = last_unsent->next);
-
- if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
- /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
- TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
- pcb->flags |= TF_FIN;
- return ERR_OK;
- }
- }
- /* no data, no length, flags, copy=1, no optdata */
- return tcp_enqueue_flags(pcb, TCP_FIN);
-}
-
-/**
- * Create a TCP segment with prefilled header.
- *
- * Called by tcp_write and tcp_enqueue_flags.
- *
- * @param pcb Protocol control block for the TCP connection.
- * @param p pbuf that is used to hold the TCP header.
- * @param flags TCP flags for header.
- * @param seqno TCP sequence number of this packet
- * @param optflags options to include in TCP header
- * @return a new tcp_seg pointing to p, or NULL.
- * The TCP header is filled in except ackno and wnd.
- * p is freed on failure.
- */
-static struct tcp_seg *
-tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
-{
- struct tcp_seg *seg;
- u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
-
- if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
- pbuf_free(p);
- return NULL;
- }
- seg->flags = optflags;
- seg->next = NULL;
- seg->p = p;
- seg->len = p->tot_len - optlen;
-#if TCP_OVERSIZE_DBGCHECK
- seg->oversize_left = 0;
-#endif /* TCP_OVERSIZE_DBGCHECK */
-#if TCP_CHECKSUM_ON_COPY
- seg->chksum = 0;
- seg->chksum_swapped = 0;
- /* check optflags */
- LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
- (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
-#endif /* TCP_CHECKSUM_ON_COPY */
-
- /* build TCP header */
- if (pbuf_header(p, TCP_HLEN)) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
- TCP_STATS_INC(tcp.err);
- tcp_seg_free(seg);
- return NULL;
- }
- seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
- seg->tcphdr->src = htons(pcb->local_port);
- seg->tcphdr->dest = htons(pcb->remote_port);
- seg->tcphdr->seqno = htonl(seqno);
- /* ackno is set in tcp_output */
- TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
- /* wnd and chksum are set in tcp_output */
- seg->tcphdr->urgp = 0;
- return seg;
-}
-
-/**
- * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
- *
- * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
- * there may be extra bytes available at the end.
- *
- * @param layer flag to define header size.
- * @param length size of the pbuf's payload.
- * @param max_length maximum usable size of payload+oversize.
- * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
- * @param pcb The TCP connection that willo enqueue the pbuf.
- * @param apiflags API flags given to tcp_write.
- * @param first_seg true when this pbuf will be used in the first enqueued segment.
- * @param
- */
-#if TCP_OVERSIZE
-static struct pbuf *
-tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
- u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
- u8_t first_seg)
-{
- struct pbuf *p;
- u16_t alloc = length;
-
-#if LWIP_NETIF_TX_SINGLE_PBUF
- LWIP_UNUSED_ARG(max_length);
- LWIP_UNUSED_ARG(pcb);
- LWIP_UNUSED_ARG(apiflags);
- LWIP_UNUSED_ARG(first_seg);
- /* always create MSS-sized pbufs */
- alloc = max_length;
-#else /* LWIP_NETIF_TX_SINGLE_PBUF */
- if (length < max_length) {
- /* Should we allocate an oversized pbuf, or just the minimum
- * length required? If tcp_write is going to be called again
- * before this segment is transmitted, we want the oversized
- * buffer. If the segment will be transmitted immediately, we can
- * save memory by allocating only length. We use a simple
- * heuristic based on the following information:
- *
- * Did the user set TCP_WRITE_FLAG_MORE?
- *
- * Will the Nagle algorithm defer transmission of this segment?
- */
- if ((apiflags & TCP_WRITE_FLAG_MORE) ||
- (!(pcb->flags & TF_NODELAY) &&
- (!first_seg ||
- pcb->unsent != NULL ||
- pcb->unacked != NULL))) {
- alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
- }
- }
-#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
- p = pbuf_alloc(layer, alloc, PBUF_RAM);
- if (p == NULL) {
- return NULL;
- }
- LWIP_ASSERT("need unchained pbuf", p->next == NULL);
- *oversize = p->len - length;
- /* trim p->len to the currently used size */
- p->len = p->tot_len = length;
- return p;
-}
-#else /* TCP_OVERSIZE */
-#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
-#endif /* TCP_OVERSIZE */
-
-#if TCP_CHECKSUM_ON_COPY
-/** Add a checksum of newly added data to the segment */
-static void
-tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
- u8_t *seg_chksum_swapped)
-{
- u32_t helper;
- /* add chksum to old chksum and fold to u16_t */
- helper = chksum + *seg_chksum;
- chksum = FOLD_U32T(helper);
- if ((len & 1) != 0) {
- *seg_chksum_swapped = 1 - *seg_chksum_swapped;
- chksum = SWAP_BYTES_IN_WORD(chksum);
- }
- *seg_chksum = chksum;
-}
-#endif /* TCP_CHECKSUM_ON_COPY */
-
-/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
- *
- * @param pcb the tcp pcb to check for
- * @param len length of data to send (checked agains snd_buf)
- * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
- */
-static err_t
-tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
-{
- /* connection is in invalid state for data transmission? */
- if ((pcb->state != ESTABLISHED) &&
- (pcb->state != CLOSE_WAIT) &&
- (pcb->state != SYN_SENT) &&
- (pcb->state != SYN_RCVD)) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
- return ERR_CONN;
- } else if (len == 0) {
- return ERR_OK;
- }
-
- /* fail on too much data */
- if (len > pcb->snd_buf) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
- len, pcb->snd_buf));
- pcb->flags |= TF_NAGLEMEMERR;
- return ERR_MEM;
- }
-
- LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: 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 */
- /* check for configured max queuelen and possible overflow */
- if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
- pcb->snd_queuelen, TCP_SND_QUEUELEN));
- TCP_STATS_INC(tcp.memerr);
- pcb->flags |= TF_NAGLEMEMERR;
- return ERR_MEM;
- }
- if (pcb->snd_queuelen != 0) {
- LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
- pcb->unacked != NULL || pcb->unsent != NULL);
- } else {
- LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
- pcb->unacked == NULL && pcb->unsent == NULL);
- }
- return ERR_OK;
-}
-
-/**
- * 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().
- *
- * @param pcb Protocol control block for the TCP connection to enqueue data for.
- * @param arg Pointer to the data to be enqueued for sending.
- * @param len Data length in bytes
- * @param apiflags combination of following flags :
- * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
- * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
- * @return ERR_OK if enqueued, another err_t on error
- */
-err_t
-tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
-{
- struct pbuf *concat_p = NULL;
- struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
- u16_t pos = 0; /* position in 'arg' data */
- u16_t queuelen;
- u8_t optlen = 0;
- u8_t optflags = 0;
-#if TCP_OVERSIZE
- u16_t oversize = 0;
- u16_t oversize_used = 0;
-#endif /* TCP_OVERSIZE */
-#if TCP_CHECKSUM_ON_COPY
- u16_t concat_chksum = 0;
- u8_t concat_chksum_swapped = 0;
- u16_t concat_chksummed = 0;
-#endif /* TCP_CHECKSUM_ON_COPY */
- err_t err;
- /* don't allocate segments bigger than half the maximum window we ever received */
- u16_t mss_local = LWIP_MIN(pcb->mss, pcb->snd_wnd_max/2);
-
-#if LWIP_NETIF_TX_SINGLE_PBUF
- /* Always copy to try to create single pbufs for TX */
- apiflags |= TCP_WRITE_FLAG_COPY;
-#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
-
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
- (void *)pcb, arg, len, (u16_t)apiflags));
- LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
- arg != NULL, return ERR_ARG;);
-
- err = tcp_write_checks(pcb, len);
- if (err != ERR_OK) {
- return err;
- }
- queuelen = pcb->snd_queuelen;
-
-#if LWIP_TCP_TIMESTAMPS
- if ((pcb->flags & TF_TIMESTAMP)) {
- optflags = TF_SEG_OPTS_TS;
- optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
- }
-#endif /* LWIP_TCP_TIMESTAMPS */
-
-
- /*
- * TCP segmentation is done in three phases with increasing complexity:
- *
- * 1. Copy data directly into an oversized pbuf.
- * 2. Chain a new pbuf to the end of pcb->unsent.
- * 3. Create new segments.
- *
- * We may run out of memory at any point. In that case we must
- * return ERR_MEM and not change anything in pcb. Therefore, all
- * changes are recorded in local variables and committed at the end
- * of the function. Some pcb fields are maintained in local copies:
- *
- * queuelen = pcb->snd_queuelen
- * oversize = pcb->unsent_oversize
- *
- * These variables are set consistently by the phases:
- *
- * seg points to the last segment tampered with.
- *
- * pos records progress as data is segmented.
- */
-
- /* Find the tail of the unsent queue. */
- if (pcb->unsent != NULL) {
- u16_t space;
- u16_t unsent_optlen;
-
- /* @todo: this could be sped up by keeping last_unsent in the pcb */
- for (last_unsent = pcb->unsent; last_unsent->next != NULL;
- last_unsent = last_unsent->next);
-
- /* Usable space at the end of the last unsent segment */
- unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
- space = mss_local - (last_unsent->len + unsent_optlen);
-
- /*
- * Phase 1: Copy data directly into an oversized pbuf.
- *
- * The number of bytes copied is recorded in the oversize_used
- * variable. The actual copying is done at the bottom of the
- * function.
- */
-#if TCP_OVERSIZE
-#if TCP_OVERSIZE_DBGCHECK
- /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
- LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
- pcb->unsent_oversize == last_unsent->oversize_left);
-#endif /* TCP_OVERSIZE_DBGCHECK */
- oversize = pcb->unsent_oversize;
- if (oversize > 0) {
- LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
- seg = last_unsent;
- oversize_used = oversize < len ? oversize : len;
- pos += oversize_used;
- oversize -= oversize_used;
- space -= oversize_used;
- }
- /* now we are either finished or oversize is zero */
- LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
-#endif /* TCP_OVERSIZE */
-
- /*
- * Phase 2: Chain a new pbuf to the end of pcb->unsent.
- *
- * We don't extend segments containing SYN/FIN flags or options
- * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
- * the end.
- */
- if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
- u16_t seglen = space < len - pos ? space : len - pos;
- seg = last_unsent;
-
- /* Create a pbuf with a copy or reference to seglen bytes. We
- * can use PBUF_RAW here since the data appears in the middle of
- * a segment. A header will never be prepended. */
- if (apiflags & TCP_WRITE_FLAG_COPY) {
- /* Data is copied */
- if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
- ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
- seglen));
- goto memerr;
- }
-#if TCP_OVERSIZE_DBGCHECK
- last_unsent->oversize_left += oversize;
-#endif /* TCP_OVERSIZE_DBGCHECK */
- TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
-#if TCP_CHECKSUM_ON_COPY
- concat_chksummed += seglen;
-#endif /* TCP_CHECKSUM_ON_COPY */
- } else {
- /* Data is not copied */
- if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
- ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
- goto memerr;
- }
-#if TCP_CHECKSUM_ON_COPY
- /* calculate the checksum of nocopy-data */
- tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
- &concat_chksum, &concat_chksum_swapped);
- concat_chksummed += seglen;
-#endif /* TCP_CHECKSUM_ON_COPY */
- /* reference the non-volatile payload data */
- concat_p->payload = (u8_t*)arg + pos;
- }
-
- pos += seglen;
- queuelen += pbuf_clen(concat_p);
- }
- } else {
-#if TCP_OVERSIZE
- LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
- pcb->unsent_oversize == 0);
-#endif /* TCP_OVERSIZE */
- }
-
- /*
- * Phase 3: Create new segments.
- *
- * The new segments are chained together in the local 'queue'
- * variable, ready to be appended to pcb->unsent.
- */
- while (pos < len) {
- struct pbuf *p;
- u16_t left = len - pos;
- u16_t max_len = mss_local - optlen;
- u16_t seglen = left > max_len ? max_len : left;
-#if TCP_CHECKSUM_ON_COPY
- u16_t chksum = 0;
- u8_t chksum_swapped = 0;
-#endif /* TCP_CHECKSUM_ON_COPY */
-
- if (apiflags & TCP_WRITE_FLAG_COPY) {
- /* If copy is set, memory should be allocated and data copied
- * into pbuf */
- if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
- goto memerr;
- }
- LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
- (p->len >= seglen));
- TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
- } else {
- /* Copy is not set: 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.
- */
- struct pbuf *p2;
-#if TCP_OVERSIZE
- LWIP_ASSERT("oversize == 0", oversize == 0);
-#endif /* TCP_OVERSIZE */
- if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
- goto memerr;
- }
-#if TCP_CHECKSUM_ON_COPY
- /* calculate the checksum of nocopy-data */
- chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
-#endif /* TCP_CHECKSUM_ON_COPY */
- /* reference the non-volatile payload data */
- p2->payload = (u8_t*)arg + pos;
-
- /* Second, allocate a pbuf for the headers. */
- if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
- /* If allocation fails, we have to deallocate the data pbuf as
- * well. */
- pbuf_free(p2);
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for header pbuf\n"));
- goto memerr;
- }
- /* Concatenate the headers and data pbufs together. */
- pbuf_cat(p/*header*/, p2/*data*/);
- }
-
- queuelen += pbuf_clen(p);
-
- /* Now that there are more segments queued, we check again if the
- * length of the queue exceeds the configured maximum or
- * overflows. */
- if ((queuelen > TCP_SND_QUEUELEN) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
- pbuf_free(p);
- goto memerr;
- }
-
- if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
- goto memerr;
- }
-#if TCP_OVERSIZE_DBGCHECK
- seg->oversize_left = oversize;
-#endif /* TCP_OVERSIZE_DBGCHECK */
-#if TCP_CHECKSUM_ON_COPY
- seg->chksum = chksum;
- seg->chksum_swapped = chksum_swapped;
- seg->flags |= TF_SEG_DATA_CHECKSUMMED;
-#endif /* TCP_CHECKSUM_ON_COPY */
-
- /* first segment of to-be-queued data? */
- if (queue == NULL) {
- queue = seg;
- } else {
- /* Attach the segment to the end of the queued segments */
- LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
- prev_seg->next = seg;
- }
- /* remember last segment of to-be-queued data for next iteration */
- prev_seg = seg;
-
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
- ntohl(seg->tcphdr->seqno),
- ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
-
- pos += seglen;
- }
-
- /*
- * All three segmentation phases were successful. We can commit the
- * transaction.
- */
-
- /*
- * Phase 1: If data has been added to the preallocated tail of
- * last_unsent, we update the length fields of the pbuf chain.
- */
-#if TCP_OVERSIZE
- if (oversize_used > 0) {
- struct pbuf *p;
- /* Bump tot_len of whole chain, len of tail */
- for (p = last_unsent->p; p; p = p->next) {
- p->tot_len += oversize_used;
- if (p->next == NULL) {
- TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
- p->len += oversize_used;
- }
- }
- last_unsent->len += oversize_used;
-#if TCP_OVERSIZE_DBGCHECK
- LWIP_ASSERT("last_unsent->oversize_left >= oversize_used",
- last_unsent->oversize_left >= oversize_used);
- last_unsent->oversize_left -= oversize_used;
-#endif /* TCP_OVERSIZE_DBGCHECK */
- }
- pcb->unsent_oversize = oversize;
-#endif /* TCP_OVERSIZE */
-
- /*
- * Phase 2: concat_p can be concatenated onto last_unsent->p
- */
- if (concat_p != NULL) {
- LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
- (last_unsent != NULL));
- pbuf_cat(last_unsent->p, concat_p);
- last_unsent->len += concat_p->tot_len;
-#if TCP_CHECKSUM_ON_COPY
- if (concat_chksummed) {
- tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
- &last_unsent->chksum_swapped);
- last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
- }
-#endif /* TCP_CHECKSUM_ON_COPY */
- }
-
- /*
- * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
- * is harmless
- */
- if (last_unsent == NULL) {
- pcb->unsent = queue;
- } else {
- last_unsent->next = queue;
- }
-
- /*
- * Finally update the pcb state.
- */
- pcb->snd_lbb += len;
- pcb->snd_buf -= len;
- pcb->snd_queuelen = queuelen;
-
- LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
- pcb->snd_queuelen));
- if (pcb->snd_queuelen != 0) {
- LWIP_ASSERT("tcp_write: valid queue length",
- pcb->unacked != NULL || pcb->unsent != NULL);
- }
-
- /* Set the PSH flag in the last segment that we enqueued. */
- if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
- TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
- }
-
- return ERR_OK;
-memerr:
- pcb->flags |= TF_NAGLEMEMERR;
- TCP_STATS_INC(tcp.memerr);
-
- if (concat_p != NULL) {
- pbuf_free(concat_p);
- }
- if (queue != NULL) {
- tcp_segs_free(queue);
- }
- if (pcb->snd_queuelen != 0) {
- LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
- pcb->unsent != NULL);
- }
- LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
- return ERR_MEM;
-}
-
-/**
- * Enqueue TCP options for transmission.
- *
- * Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
- *
- * @param pcb Protocol control block for the TCP connection.
- * @param flags TCP header flags to set in the outgoing segment.
- * @param optdata pointer to TCP options, or NULL.
- * @param optlen length of TCP options in bytes.
- */
-err_t
-tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
-{
- struct pbuf *p;
- struct tcp_seg *seg;
- u8_t optflags = 0;
- u8_t optlen = 0;
-
- LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
-
- LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
- (flags & (TCP_SYN | TCP_FIN)) != 0);
-
- /* check for configured max queuelen and possible overflow */
- if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
- pcb->snd_queuelen, TCP_SND_QUEUELEN));
- TCP_STATS_INC(tcp.memerr);
- pcb->flags |= TF_NAGLEMEMERR;
- return ERR_MEM;
- }
-
- if (flags & TCP_SYN) {
- optflags = TF_SEG_OPTS_MSS;
- }
-#if LWIP_TCP_TIMESTAMPS
- if ((pcb->flags & TF_TIMESTAMP)) {
- optflags |= TF_SEG_OPTS_TS;
- }
-#endif /* LWIP_TCP_TIMESTAMPS */
- optlen = LWIP_TCP_OPT_LENGTH(optflags);
-
- /* tcp_enqueue_flags is always called with either SYN or FIN in flags.
- * We need one available snd_buf byte to do that.
- * This means we can't send FIN while snd_buf==0. A better fix would be to
- * not include SYN and FIN sequence numbers in the snd_buf count. */
- if (pcb->snd_buf == 0) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: no send buffer available\n"));
- TCP_STATS_INC(tcp.memerr);
- return ERR_MEM;
- }
-
- /* Allocate pbuf with room for TCP header + options */
- if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
- pcb->flags |= TF_NAGLEMEMERR;
- TCP_STATS_INC(tcp.memerr);
- return ERR_MEM;
- }
- LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
- (p->len >= optlen));
-
- /* Allocate memory for tcp_seg, and fill in fields. */
- if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
- pcb->flags |= TF_NAGLEMEMERR;
- TCP_STATS_INC(tcp.memerr);
- return ERR_MEM;
- }
- LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
- LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
-
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
- ("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
- ntohl(seg->tcphdr->seqno),
- ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
- (u16_t)flags));
-
- /* Now append seg to pcb->unsent queue */
- if (pcb->unsent == NULL) {
- pcb->unsent = seg;
- } else {
- struct tcp_seg *useg;
- for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
- useg->next = seg;
- }
-#if TCP_OVERSIZE
- /* The new unsent tail has no space */
- pcb->unsent_oversize = 0;
-#endif /* TCP_OVERSIZE */
-
- /* SYN and FIN bump the sequence number */
- if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
- pcb->snd_lbb++;
- /* optlen does not influence snd_buf */
- pcb->snd_buf--;
- }
- if (flags & TCP_FIN) {
- pcb->flags |= TF_FIN;
- }
-
- /* update number of segments on the queues */
- pcb->snd_queuelen += pbuf_clen(seg->p);
- LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
- if (pcb->snd_queuelen != 0) {
- LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
- pcb->unacked != NULL || pcb->unsent != NULL);
- }
-
- return ERR_OK;
-}
-
-#if LWIP_TCP_TIMESTAMPS
-/* Build a timestamp option (12 bytes long) at the specified options pointer)
- *
- * @param pcb tcp_pcb
- * @param opts option pointer where to store the timestamp option
- */
-static void
-tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
-{
- /* Pad with two NOP options to make everything nicely aligned */
- opts[0] = PP_HTONL(0x0101080A);
- opts[1] = htonl(sys_now());
- opts[2] = htonl(pcb->ts_recent);
-}
-#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 = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
- if (p == NULL) {
- LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
- return ERR_BUF;
- }
- tcphdr = (struct tcp_hdr *)p->payload;
- 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);
-
- /* 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
- *
- * @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 */
-
- /* pcb->state LISTEN not allowed here */
- LWIP_ASSERT("don't call tcp_output for listen-pcbs",
- pcb->state != LISTEN);
-
- /* 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
- 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 %"U16_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 %"U16_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) {
- LWIP_ASSERT("RST not expected here!",
- (TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
- /* Stop sending if the nagle algorithm would prevent it
- * Don't stop:
- * - if tcp_write had a memory error before (prevent delayed ACK timeout) or
- * - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
- * either seg->next != NULL or pcb->unacked == NULL;
- * RST is no sent using tcp_write/tcp_output.
- */
- if((tcp_do_output_nagle(pcb) == 0) &&
- ((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)){
- break;
- }
-#if TCP_CWND_DEBUG
- LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_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);
- snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
- if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
- pcb->snd_nxt = 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 somewhere before it. 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 before tail of unacked list, keeping the list sorted */
- struct tcp_seg **cur_seg = &(pcb->unacked);
- while (*cur_seg &&
- TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
- cur_seg = &((*cur_seg)->next );
- }
- seg->next = (*cur_seg);
- (*cur_seg) = 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;
- }
-#if TCP_OVERSIZE
- if (pcb->unsent == NULL) {
- /* last unsent has been removed, reset unsent_oversize */
- pcb->unsent_oversize = 0;
- }
-#endif /* TCP_OVERSIZE */
-
- pcb->flags &= ~TF_NAGLEMEMERR;
- return ERR_OK;
-}
-
-/**
- * Called by tcp_output() to actually send a TCP segment over IP.
- *
- * @param seg the tcp_seg to send
- * @param pcb the tcp_pcb for the TCP connection used to send the segment
- */
-static void
-tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
-{
- u16_t len;
- struct netif *netif;
- u32_t *opts;
-
- /** @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);
-
- /* advertise our receive window size in this TCP segment */
- seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
-
- pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
-
- /* Add any requested options. NB MSS option is only set on SYN
- packets, so ignore it here */
- opts = (u32_t *)(void *)(seg->tcphdr + 1);
- if (seg->flags & TF_SEG_OPTS_MSS) {
- u16_t mss;
-#if TCP_CALCULATE_EFF_SEND_MSS
- mss = tcp_eff_send_mss(TCP_MSS, &pcb->remote_ip);
-#else /* TCP_CALCULATE_EFF_SEND_MSS */
- mss = TCP_MSS;
-#endif /* TCP_CALCULATE_EFF_SEND_MSS */
- *opts = TCP_BUILD_MSS_OPTION(mss);
- opts += 1;
- }
-#if LWIP_TCP_TIMESTAMPS
- pcb->ts_lastacksent = pcb->rcv_nxt;
-
- if (seg->flags & TF_SEG_OPTS_TS) {
- tcp_build_timestamp_option(pcb, opts);
- opts += 3;
- }
-#endif
-
- /* Set retransmission timer running if it is not currently enabled
- This must be set before checking the route. */
- if (pcb->rtime == -1) {
- pcb->rtime = 0;
- }
-
- /* 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_copy(pcb->local_ip, netif->ip_addr);
- }
-
- 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
-#if TCP_CHECKSUM_ON_COPY
- {
- u32_t acc;
-#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
- u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
- &(pcb->remote_ip),
- IP_PROTO_TCP, seg->p->tot_len);
-#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
- if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
- LWIP_ASSERT("data included but not checksummed",
- seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
- }
-
- /* rebuild TCP header checksum (TCP header changes for retransmissions!) */
- acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
- &(pcb->remote_ip),
- IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
- /* add payload checksum */
- if (seg->chksum_swapped) {
- seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
- seg->chksum_swapped = 0;
- }
- acc += (u16_t)~(seg->chksum);
- seg->tcphdr->chksum = FOLD_U32T(acc);
-#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
- if (chksum_slow != seg->tcphdr->chksum) {
- LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING,
- ("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
- seg->tcphdr->chksum, chksum_slow));
- seg->tcphdr->chksum = chksum_slow;
- }
-#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
- }
-#else /* TCP_CHECKSUM_ON_COPY */
- seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
- &(pcb->remote_ip),
- IP_PROTO_TCP, seg->p->tot_len);
-#endif /* TCP_CHECKSUM_ON_COPY */
-#endif /* CHECKSUM_GEN_TCP */
- TCP_STATS_INC(tcp.xmit);
-
-#if LWIP_NETIF_HWADDRHINT
- ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
- IP_PROTO_TCP, &(pcb->addr_hint));
-#else /* LWIP_NETIF_HWADDRHINT*/
- ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
- IP_PROTO_TCP);
-#endif /* LWIP_NETIF_HWADDRHINT*/
-}
-
-/**
- * Send a TCP RESET packet (empty segment with RST flag set) either to
- * abort a connection or to show that there is no matching local connection
- * for a received segment.
- *
- * Called by tcp_abort() (to abort a local connection), tcp_input() (if no
- * matching local pcb was found), tcp_listen_input() (if incoming segment
- * has ACK flag set) and tcp_process() (received segment in the wrong state)
- *
- * Since a RST segment is in most cases not sent for an active connection,
- * tcp_rst() has a number of arguments that are taken from a tcp_pcb for
- * most other segment output functions.
- *
- * @param seqno the sequence number to use for the outgoing segment
- * @param ackno the acknowledge number to use for the outgoing segment
- * @param local_ip the local IP address to send the segment from
- * @param remote_ip the remote IP address to send the segment to
- * @param local_port the local TCP port to send the segment from
- * @param remote_port the remote TCP port to send the segment to
- */
-void
-tcp_rst(u32_t seqno, u32_t ackno,
- ip_addr_t *local_ip, ip_addr_t *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;
- }
- LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
- (p->len >= sizeof(struct tcp_hdr)));
-
- tcphdr = (struct tcp_hdr *)p->payload;
- tcphdr->src = htons(local_port);
- tcphdr->dest = htons(remote_port);
- tcphdr->seqno = htonl(seqno);
- tcphdr->ackno = htonl(ackno);
- TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST | TCP_ACK);
- tcphdr->wnd = PP_HTONS(TCP_WND);
- tcphdr->chksum = 0;
- tcphdr->urgp = 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
- *
- * Called by tcp_slowtmr() for slow retransmission.
- *
- * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
- */
-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;
- /* last unsent hasn't changed, no need to reset unsent_oversize */
-
- /* increment number of retransmissions */
- ++pcb->nrtx;
-
- /* Don't take any RTT measurements after retransmitting. */
- pcb->rttest = 0;
-
- /* Do the actual retransmission */
- tcp_output(pcb);
-}
-
-/**
- * Requeue the first unacked segment for retransmission
- *
- * Called by tcp_receive() for fast retramsmit.
- *
- * @param pcb the tcp_pcb for which to retransmit the first unacked segment
- */
-void
-tcp_rexmit(struct tcp_pcb *pcb)
-{
- struct tcp_seg *seg;
- struct tcp_seg **cur_seg;
-
- if (pcb->unacked == NULL) {
- return;
- }
-
- /* Move the first unacked segment to the unsent queue */
- /* Keep the unsent queue sorted. */
- seg = pcb->unacked;
- pcb->unacked = seg->next;
-
- cur_seg = &(pcb->unsent);
- while (*cur_seg &&
- TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
- cur_seg = &((*cur_seg)->next );
- }
- seg->next = *cur_seg;
- *cur_seg = seg;
-#if TCP_OVERSIZE
- if (seg->next == NULL) {
- /* the retransmitted segment is last in unsent, so reset unsent_oversize */
- pcb->unsent_oversize = 0;
- }
-#endif /* TCP_OVERSIZE */
-
- ++pcb->nrtx;
-
- /* Don't take any rtt measurements after retransmitting. */
- pcb->rttest = 0;
-
- /* Do the actual retransmission. */
- snmp_inc_tcpretranssegs();
- /* No need to call tcp_output: we are always called from tcp_input()
- and thus tcp_output directly returns. */
-}
-
-
-/**
- * Handle retransmission after three dupacks received
- *
- * @param pcb the tcp_pcb for which to retransmit the first unacked segment
- */
-void
-tcp_rexmit_fast(struct tcp_pcb *pcb)
-{
- if (pcb->unacked != NULL && !(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 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;
- }
-}
-
-
-/**
- * Send keepalive packets to keep a connection active although
- * no data is sent over it.
- *
- * Called by tcp_slowtmr()
- *
- * @param pcb the tcp_pcb for which to send a keepalive packet
- */
-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_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
- ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
-
- LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
- tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
-
- p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
- if(p == NULL) {
- LWIP_DEBUGF(TCP_DEBUG,
- ("tcp_keepalive: could not allocate memory for pbuf\n"));
- return;
- }
- tcphdr = (struct tcp_hdr *)p->payload;
-
-#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 */
-#if LWIP_NETIF_HWADDRHINT
- ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
- &(pcb->addr_hint));
-#else /* LWIP_NETIF_HWADDRHINT*/
- ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
-#endif /* LWIP_NETIF_HWADDRHINT*/
-
- pbuf_free(p);
-
- LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
- pcb->snd_nxt - 1, pcb->rcv_nxt));
-}
-
-
-/**
- * Send persist timer zero-window probes to keep a connection active
- * when a window update is lost.
- *
- * Called by tcp_slowtmr()
- *
- * @param pcb the tcp_pcb for which to send a zero-window probe packet
- */
-void
-tcp_zero_window_probe(struct tcp_pcb *pcb)
-{
- struct pbuf *p;
- struct tcp_hdr *tcphdr;
- struct tcp_seg *seg;
- u16_t len;
- u8_t is_fin;
-
- LWIP_DEBUGF(TCP_DEBUG,
- ("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
- U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
- ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
- ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
-
- LWIP_DEBUGF(TCP_DEBUG,
- ("tcp_zero_window_probe: tcp_ticks %"U32_F
- " pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
- tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
-
- seg = pcb->unacked;
-
- if(seg == NULL) {
- seg = pcb->unsent;
- }
- if(seg == NULL) {
- return;
- }
-
- is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
- /* we want to send one seqno: either FIN or data (no options) */
- len = is_fin ? 0 : 1;
-
- p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
- if(p == NULL) {
- LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
- return;
- }
- tcphdr = (struct tcp_hdr *)p->payload;
-
- if (is_fin) {
- /* FIN segment, no data */
- TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
- } else {
- /* Data segment, copy in one byte from the head of the unacked queue */
- char *d = ((char *)p->payload + TCP_HLEN);
- /* Depending on whether the segment has already been sent (unacked) or not
- (unsent), seg->p->payload points to the IP header or TCP header.
- Ensure we copy the first TCP data byte: */
- pbuf_copy_partial(seg->p, d, 1, seg->p->tot_len - seg->len);
- }
-
-#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 */
-#if LWIP_NETIF_HWADDRHINT
- ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
- &(pcb->addr_hint));
-#else /* LWIP_NETIF_HWADDRHINT*/
- ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
-#endif /* LWIP_NETIF_HWADDRHINT*/
-
- pbuf_free(p);
-
- LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
- " ackno %"U32_F".\n",
- pcb->snd_nxt - 1, pcb->rcv_nxt));
-}
-#endif /* LWIP_TCP */
projects / reactos.git / blobdiff