1473 lines
49 KiB
C
1473 lines
49 KiB
C
/**
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* @file
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* Transmission Control Protocol, outgoing traffic
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*
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* The output functions of TCP.
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*
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*/
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/*
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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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*/
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#include "lwip/opt.h"
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#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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#include "lwip/tcp_impl.h"
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#include "lwip/def.h"
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#include "lwip/mem.h"
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#include "lwip/memp.h"
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#include "lwip/sys.h"
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#include "lwip/ip_addr.h"
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#include "lwip/netif.h"
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#include "lwip/inet_chksum.h"
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#include "lwip/stats.h"
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#include "lwip/snmp.h"
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#include <string.h>
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/* Define some copy-macros for checksum-on-copy so that the code looks
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nicer by preventing too many ifdef's. */
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#if TCP_CHECKSUM_ON_COPY
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#define TCP_DATA_COPY(dst, src, len, seg) do { \
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tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
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len, &seg->chksum, &seg->chksum_swapped); \
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seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
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#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
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tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
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#else /* TCP_CHECKSUM_ON_COPY*/
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#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
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#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
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#endif /* TCP_CHECKSUM_ON_COPY*/
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/** Define this to 1 for an extra check that the output checksum is valid
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* (usefule when the checksum is generated by the application, not the stack) */
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#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
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#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
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#endif
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/* Forward declarations.*/
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static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb);
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/** Allocate a pbuf and create a tcphdr at p->payload, used for output
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* functions other than the default tcp_output -> tcp_output_segment
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* (e.g. tcp_send_empty_ack, etc.)
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*
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* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
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* @param optlen length of header-options
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* @param datalen length of tcp data to reserve in pbuf
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* @param seqno_be seqno in network byte order (big-endian)
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* @return pbuf with p->payload being the tcp_hdr
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*/
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static struct pbuf *ICACHE_FLASH_ATTR
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tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
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u32_t seqno_be /* already in network byte order */)
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{
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struct tcp_hdr *tcphdr;
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struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
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if (p != NULL) {
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LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
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(p->len >= TCP_HLEN + optlen));
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tcphdr = (struct tcp_hdr *)p->payload;
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tcphdr->src = htons(pcb->local_port);
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tcphdr->dest = htons(pcb->remote_port);
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tcphdr->seqno = seqno_be;
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tcphdr->ackno = htonl(pcb->rcv_nxt);
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TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
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tcphdr->wnd = htons(pcb->rcv_ann_wnd);
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tcphdr->chksum = 0;
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tcphdr->urgp = 0;
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/* If we're sending a packet, update the announced right window edge */
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pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
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}
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return p;
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}
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/**
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* Called by tcp_close() to send a segment including FIN flag but not data.
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*
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* @param pcb the tcp_pcb over which to send a segment
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* @return ERR_OK if sent, another err_t otherwise
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*/
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err_t
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tcp_send_fin(struct tcp_pcb *pcb)
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{
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/* first, try to add the fin to the last unsent segment */
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if (pcb->unsent != NULL) {
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struct tcp_seg *last_unsent;
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for (last_unsent = pcb->unsent; last_unsent->next != NULL;
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last_unsent = last_unsent->next);
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if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
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/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
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TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
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return ERR_OK;
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}
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}
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/* no data, no length, flags, copy=1, no optdata */
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return tcp_enqueue_flags(pcb, TCP_FIN);
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}
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/**
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* Create a TCP segment with prefilled header.
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*
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* Called by tcp_write and tcp_enqueue_flags.
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*
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* @param pcb Protocol control block for the TCP connection.
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* @param p pbuf that is used to hold the TCP header.
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* @param flags TCP flags for header.
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* @param seqno TCP sequence number of this packet
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* @param optflags options to include in TCP header
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* @return a new tcp_seg pointing to p, or NULL.
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* The TCP header is filled in except ackno and wnd.
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* p is freed on failure.
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*/
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static struct tcp_seg *ICACHE_FLASH_ATTR
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tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
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{
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struct tcp_seg *seg;
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u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
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if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
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LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
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pbuf_free(p);
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return NULL;
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}
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seg->flags = optflags;
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seg->next = NULL;
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seg->p = p;
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seg->len = p->tot_len - optlen;
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#if TCP_OVERSIZE_DBGCHECK
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seg->oversize_left = 0;
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#endif /* TCP_OVERSIZE_DBGCHECK */
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#if TCP_CHECKSUM_ON_COPY
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seg->chksum = 0;
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seg->chksum_swapped = 0;
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/* check optflags */
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LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
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(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
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#endif /* TCP_CHECKSUM_ON_COPY */
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/* build TCP header */
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if (pbuf_header(p, TCP_HLEN)) {
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LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
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TCP_STATS_INC(tcp.err);
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tcp_seg_free(seg);
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return NULL;
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}
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seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
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seg->tcphdr->src = htons(pcb->local_port);
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seg->tcphdr->dest = htons(pcb->remote_port);
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seg->tcphdr->seqno = htonl(seqno);
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/* ackno is set in tcp_output */
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TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
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/* wnd and chksum are set in tcp_output */
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seg->tcphdr->urgp = 0;
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return seg;
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}
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/**
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* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
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*
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* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
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* there may be extra bytes available at the end.
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*
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* @param layer flag to define header size.
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* @param length size of the pbuf's payload.
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* @param max_length maximum usable size of payload+oversize.
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* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
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* @param pcb The TCP connection that willo enqueue the pbuf.
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* @param apiflags API flags given to tcp_write.
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* @param first_seg true when this pbuf will be used in the first enqueued segment.
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* @param
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*/
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#if TCP_OVERSIZE
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static struct pbuf *ICACHE_FLASH_ATTR
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tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
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u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
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u8_t first_seg)
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{
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struct pbuf *p;
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u16_t alloc = length;
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#if LWIP_NETIF_TX_SINGLE_PBUF
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LWIP_UNUSED_ARG(max_length);
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LWIP_UNUSED_ARG(pcb);
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LWIP_UNUSED_ARG(apiflags);
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LWIP_UNUSED_ARG(first_seg);
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/* always create MSS-sized pbufs */
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alloc = TCP_MSS;
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#else /* LWIP_NETIF_TX_SINGLE_PBUF */
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if (length < max_length) {
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/* Should we allocate an oversized pbuf, or just the minimum
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* length required? If tcp_write is going to be called again
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* before this segment is transmitted, we want the oversized
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* buffer. If the segment will be transmitted immediately, we can
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* save memory by allocating only length. We use a simple
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* heuristic based on the following information:
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*
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* Did the user set TCP_WRITE_FLAG_MORE?
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*
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* Will the Nagle algorithm defer transmission of this segment?
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*/
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if ((apiflags & TCP_WRITE_FLAG_MORE) ||
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(!(pcb->flags & TF_NODELAY) &&
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(!first_seg ||
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pcb->unsent != NULL ||
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pcb->unacked != NULL))) {
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alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
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}
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}
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#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
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p = pbuf_alloc(layer, alloc, PBUF_RAM);
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if (p == NULL) {
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return NULL;
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}
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LWIP_ASSERT("need unchained pbuf", p->next == NULL);
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*oversize = p->len - length;
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/* trim p->len to the currently used size */
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p->len = p->tot_len = length;
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return p;
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}
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#else /* TCP_OVERSIZE */
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#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
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#endif /* TCP_OVERSIZE */
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#if TCP_CHECKSUM_ON_COPY
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/** Add a checksum of newly added data to the segment */
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static void ICACHE_FLASH_ATTR
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tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
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u8_t *seg_chksum_swapped)
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{
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u32_t helper;
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/* add chksum to old chksum and fold to u16_t */
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helper = chksum + *seg_chksum;
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chksum = FOLD_U32T(helper);
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if ((len & 1) != 0) {
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*seg_chksum_swapped = 1 - *seg_chksum_swapped;
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chksum = SWAP_BYTES_IN_WORD(chksum);
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}
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*seg_chksum = chksum;
|
||
}
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#endif /* TCP_CHECKSUM_ON_COPY */
|
||
|
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/** 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 ICACHE_FLASH_ATTR
|
||
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).
|
||
*<2A><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݣ<EFBFBD><DDA3>ú<EFBFBD><C3BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD>Ķβ<C4B6><CEB2><EFBFBD><EFBFBD>ڿ<EFBFBD><DABF>ƿ黺<C6BF><E9BBBA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
* 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.<2E><>Ӧ<EFBFBD><D3A6><EFBFBD>ӿ<EFBFBD><D3BF>ƿ<EFBFBD>
|
||
* @param arg Pointer to the data to be enqueued for sending.<2E><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʼ<EFBFBD><CABC>ַ
|
||
* @param len Data length in bytes<65><73><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݳ<EFBFBD><DDB3><EFBFBD>
|
||
* @param apiflags combination of following flags :<3A><><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7><EFBFBD><EFBFBD>п<EFBFBD><D0BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Լ<EFBFBD><D4BC><EFBFBD><EFBFBD>Ķ<EFBFBD><C4B6>ײ<EFBFBD><D7B2>Ƿ<EFBFBD><C7B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>PSH<53><48>־
|
||
* - 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;
|
||
|
||
#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 = pcb->mss - (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 = pcb->mss - 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, pcb->mss, &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
|
||
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 ICACHE_FLASH_ATTR
|
||
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
|
||
*<2A><><EFBFBD>Ϳ<EFBFBD><CDBF>ƿ黺<C6BF><E9BBBA><EFBFBD><EFBFBD><EFBFBD>еı<D0B5><C4B1>Ķ<EFBFBD>
|
||
* @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 ICACHE_FLASH_ATTR
|
||
tcp_output(struct tcp_pcb *pcb)
|
||
{
|
||
struct tcp_seg *seg, *useg;
|
||
u32_t wnd, snd_nxt;
|
||
#if TCP_CWND_DEBUG
|
||
s16_t i = 0;
|
||
#endif /* TCP_CWND_DEBUG */
|
||
/* First, check if we are invoked by the TCP input processing
|
||
code. If so, we do not output anything. Instead, we rely on the
|
||
input processing code to call us when input processing is done
|
||
with. <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƿ鵱ǰ<E9B5B1><C7B0><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD>ӷ<EFBFBD><D3B7><EFBFBD>*/
|
||
if (tcp_input_pcb == pcb) {
|
||
return ERR_OK;
|
||
}
|
||
|
||
wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);//<2F>ӷ<EFBFBD><D3B7>ʹ<EFBFBD><CDB4>ں<EFBFBD><DABA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡС<C8A1>ߵõ<DFB5><C3B5><EFBFBD>Ч<EFBFBD><D0A7><EFBFBD>ʹ<EFBFBD><CDB4><EFBFBD>
|
||
|
||
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);//<2F><><EFBFBD><EFBFBD>ֻ<EFBFBD><D6BB>ACK<43>ı<EFBFBD><C4B1>Ķ<EFBFBD>
|
||
}
|
||
|
||
/* useg should point to last segment on unacked queue */
|
||
useg = pcb->unacked;
|
||
if (useg != NULL) {
|
||
for (; useg->next != NULL; useg = useg->next);//<2F>õ<EFBFBD>β<EFBFBD><CEB2>
|
||
}
|
||
|
||
#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?
|
||
*<2A><>ǰ<EFBFBD><C7B0>Ч<EFBFBD><D0A7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ķ<EFBFBD><C4B7>ͣ<EFBFBD>ѭ<EFBFBD><D1AD><EFBFBD><EFBFBD><EFBFBD>ͱ<EFBFBD><CDB1>ģ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>*/
|
||
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);//<2F><>д<EFBFBD>ײ<EFBFBD>ACK<43><4B>־
|
||
pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>־λ
|
||
}
|
||
|
||
tcp_output_segment(seg, pcb);//<2F><><EFBFBD>ú<EFBFBD><C3BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͱ<EFBFBD><CDB1>Ķ<EFBFBD>
|
||
|
||
snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);//<2F><><EFBFBD><EFBFBD>snd_nxt
|
||
if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
||
pcb->snd_nxt = snd_nxt;//<2F><><EFBFBD><EFBFBD>Ҫ<EFBFBD><D2AA><EFBFBD>͵<EFBFBD><CDB5><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1><EFBFBD>
|
||
}
|
||
/* put segment on unacknowledged list if length > 0 <20><><EFBFBD><EFBFBD>ȥ<EFBFBD>ı<EFBFBD><C4B1>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD>ݳ<EFBFBD><DDB3>Ȳ<EFBFBD>Ϊ0<CEAA><30><EFBFBD><EFBFBD><EFBFBD>ߴ<EFBFBD><DFB4><EFBFBD>
|
||
* <20><>SYN<59><4E>FIN<49><4E>־<EFBFBD><D6BE><EFBFBD>ñ<F2BDABB8><C3B1>Ķμ<C4B6><CEBC>뵽δȷ<CEB4>϶<EFBFBD><CFB6>У<EFBFBD><D0A3>Ա㳬ʱ<E3B3AC>ش<EFBFBD>*/
|
||
if (TCP_TCPLEN(seg) > 0) {
|
||
seg->next = NULL;
|
||
/* unacked list is empty? ֱ<>ӹҽ<D3B9>*/
|
||
if (pcb->unacked == NULL) {
|
||
pcb->unacked = seg;
|
||
useg = seg;
|
||
/* unacked list is not empty?<3F><><EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0><EFBFBD>İ<EFBFBD>˳<EFBFBD><CBB3><EFBFBD><EFBFBD>֯<EFBFBD>ڶ<EFBFBD><DAB6><EFBFBD><EFBFBD><EFBFBD> */
|
||
} 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 */ //<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0><EFBFBD>ĵ<EFBFBD><C4B5><EFBFBD><EFBFBD>кŵ<D0BA><C5B5>ڶ<EFBFBD><DAB6><EFBFBD>β<EFBFBD><CEB2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>кţ<D0BA>
|
||
//<2F>Ӷ<EFBFBD><D3B6><EFBFBD><EFBFBD>ײ<EFBFBD><D7B2><EFBFBD>ʼ
|
||
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 {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ߣ<EFBFBD><DFA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>δȷ<CEB4>϶<EFBFBD><CFB6><EFBFBD>ĩβ
|
||
/* add segment to tail of unacked list */
|
||
useg->next = seg;
|
||
useg = useg->next;
|
||
}
|
||
}
|
||
/* do not queue empty segments on the unacked list */
|
||
} else {//<2F><><EFBFBD>Ķγ<C4B6><CEB3><EFBFBD>Ϊ0<CEAA><30>ֱ<EFBFBD><D6B1>ɾ<EFBFBD><C9BE><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ش<EFBFBD>
|
||
tcp_seg_free(seg);
|
||
}
|
||
seg = pcb->unsent;//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD>
|
||
}
|
||
#if TCP_OVERSIZE
|
||
if (pcb->unsent == NULL) {
|
||
/* last unsent has been removed, reset unsent_oversize */
|
||
pcb->unsent_oversize = 0;
|
||
}
|
||
#endif /* TCP_OVERSIZE */
|
||
|
||
//<2F><><EFBFBD>ʹ<EFBFBD><CDB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>±<EFBFBD><C2B1>IJ<EFBFBD><C4B2>ܷ<EFBFBD><DCB7>ͣ<EFBFBD><CDA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>㴰<EFBFBD><E3B4B0>̽<EFBFBD>⡣
|
||
if (seg != NULL && pcb->persist_backoff == 0 &&
|
||
ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
|
||
/* prepare for persist timer */
|
||
pcb->persist_cnt = 0;
|
||
pcb->persist_backoff = 1;
|
||
}
|
||
|
||
pcb->flags &= ~TF_NAGLEMEMERR;//<2F><><EFBFBD>ڴ<EFBFBD><DAB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>־
|
||
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 */
|
||
LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
|
||
opts = (u32_t *)(void *)(seg->tcphdr + 1);
|
||
if (seg->flags & TF_SEG_OPTS_MSS) {
|
||
TCP_BUILD_MSS_OPTION(*opts);
|
||
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. modify by ives at 2014.4.24*/
|
||
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;
|
||
|
||
/* 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;
|
||
|
||
++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 */
|
||
struct tcp_hdr *thdr = (struct tcp_hdr *)seg->p->payload;
|
||
char *d = ((char *)p->payload + TCP_HLEN);
|
||
pbuf_copy_partial(seg->p, d, 1, TCPH_HDRLEN(thdr) * 4);
|
||
}
|
||
|
||
#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 */
|