[164] | 1 | /**
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| 2 | * @file
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| 3 | * Transmission Control Protocol, outgoing traffic
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| 4 | *
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| 5 | * The output functions of TCP.
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| 6 | *
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| 7 | */
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| 8 |
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| 9 | /*
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| 10 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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| 11 | * All rights reserved.
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| 12 | *
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| 13 | * Redistribution and use in source and binary forms, with or without modification,
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| 14 | * are permitted provided that the following conditions are met:
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| 15 | *
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| 16 | * 1. Redistributions of source code must retain the above copyright notice,
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| 17 | * this list of conditions and the following disclaimer.
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| 18 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 19 | * this list of conditions and the following disclaimer in the documentation
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| 20 | * and/or other materials provided with the distribution.
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| 21 | * 3. The name of the author may not be used to endorse or promote products
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| 22 | * derived from this software without specific prior written permission.
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| 23 | *
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 25 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 26 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 27 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 28 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 29 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 30 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 31 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 32 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 33 | * OF SUCH DAMAGE.
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| 34 | *
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| 35 | * This file is part of the lwIP TCP/IP stack.
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| 36 | *
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| 37 | * Author: Adam Dunkels <adam@sics.se>
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| 38 | *
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| 39 | */
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| 40 |
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| 41 | #include "lwip/opt.h"
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| 42 |
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| 43 | #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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| 44 |
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| 45 | #include "lwip/tcp_impl.h"
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| 46 | #include "lwip/def.h"
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| 47 | #include "lwip/mem.h"
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| 48 | #include "lwip/memp.h"
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| 49 | #include "lwip/ip_addr.h"
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| 50 | #include "lwip/netif.h"
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| 51 | #include "lwip/inet_chksum.h"
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| 52 | #include "lwip/stats.h"
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| 53 | #include "lwip/snmp.h"
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| 54 | #if LWIP_TCP_TIMESTAMPS
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| 55 | #include "lwip/sys.h"
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| 56 | #endif
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| 57 |
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| 58 | #include <string.h>
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| 59 |
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| 60 | /* Define some copy-macros for checksum-on-copy so that the code looks
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| 61 | nicer by preventing too many ifdef's. */
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| 62 | #if TCP_CHECKSUM_ON_COPY
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| 63 | #define TCP_DATA_COPY(dst, src, len, seg) do { \
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| 64 | tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
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| 65 | len, &seg->chksum, &seg->chksum_swapped); \
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| 66 | seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
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| 67 | #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
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| 68 | tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
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| 69 | #else /* TCP_CHECKSUM_ON_COPY*/
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| 70 | #define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
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| 71 | #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
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| 72 | #endif /* TCP_CHECKSUM_ON_COPY*/
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| 73 |
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| 74 | /** Define this to 1 for an extra check that the output checksum is valid
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| 75 | * (usefule when the checksum is generated by the application, not the stack) */
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| 76 | #ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
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| 77 | #define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
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| 78 | #endif
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| 79 |
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| 80 | /* Forward declarations.*/
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| 81 | static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb);
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| 82 |
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| 83 | /** Allocate a pbuf and create a tcphdr at p->payload, used for output
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| 84 | * functions other than the default tcp_output -> tcp_output_segment
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| 85 | * (e.g. tcp_send_empty_ack, etc.)
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| 86 | *
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| 87 | * @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
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| 88 | * @param optlen length of header-options
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| 89 | * @param datalen length of tcp data to reserve in pbuf
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| 90 | * @param seqno_be seqno in network byte order (big-endian)
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| 91 | * @return pbuf with p->payload being the tcp_hdr
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| 92 | */
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| 93 | static struct pbuf *
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| 94 | tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
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| 95 | u32_t seqno_be /* already in network byte order */)
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| 96 | {
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| 97 | struct tcp_hdr *tcphdr;
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| 98 | struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
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| 99 | if (p != NULL) {
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| 100 | LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
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| 101 | (p->len >= TCP_HLEN + optlen));
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| 102 | tcphdr = (struct tcp_hdr *)p->payload;
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| 103 | tcphdr->src = htons(pcb->local_port);
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| 104 | tcphdr->dest = htons(pcb->remote_port);
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| 105 | tcphdr->seqno = seqno_be;
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| 106 | tcphdr->ackno = htonl(pcb->rcv_nxt);
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| 107 | TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
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| 108 | tcphdr->wnd = htons(pcb->rcv_ann_wnd);
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| 109 | tcphdr->chksum = 0;
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| 110 | tcphdr->urgp = 0;
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| 111 |
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| 112 | /* If we're sending a packet, update the announced right window edge */
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| 113 | pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
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| 114 | }
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| 115 | return p;
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| 116 | }
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| 117 |
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| 118 | /**
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| 119 | * Called by tcp_close() to send a segment including FIN flag but not data.
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| 120 | *
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| 121 | * @param pcb the tcp_pcb over which to send a segment
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| 122 | * @return ERR_OK if sent, another err_t otherwise
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| 123 | */
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| 124 | err_t
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| 125 | tcp_send_fin(struct tcp_pcb *pcb)
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| 126 | {
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| 127 | /* first, try to add the fin to the last unsent segment */
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| 128 | if (pcb->unsent != NULL) {
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| 129 | struct tcp_seg *last_unsent;
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| 130 | for (last_unsent = pcb->unsent; last_unsent->next != NULL;
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| 131 | last_unsent = last_unsent->next);
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| 132 |
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| 133 | if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
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| 134 | /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
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| 135 | TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
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| 136 | pcb->flags |= TF_FIN;
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| 137 | return ERR_OK;
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| 138 | }
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| 139 | }
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| 140 | /* no data, no length, flags, copy=1, no optdata */
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| 141 | return tcp_enqueue_flags(pcb, TCP_FIN);
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| 142 | }
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| 143 |
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| 144 | /**
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| 145 | * Create a TCP segment with prefilled header.
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| 146 | *
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| 147 | * Called by tcp_write and tcp_enqueue_flags.
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| 148 | *
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| 149 | * @param pcb Protocol control block for the TCP connection.
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| 150 | * @param p pbuf that is used to hold the TCP header.
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| 151 | * @param flags TCP flags for header.
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| 152 | * @param seqno TCP sequence number of this packet
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| 153 | * @param optflags options to include in TCP header
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| 154 | * @return a new tcp_seg pointing to p, or NULL.
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| 155 | * The TCP header is filled in except ackno and wnd.
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| 156 | * p is freed on failure.
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| 157 | */
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| 158 | static struct tcp_seg *
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| 159 | tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
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| 160 | {
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| 161 | struct tcp_seg *seg;
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| 162 | u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
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| 163 |
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| 164 | if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
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| 165 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
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| 166 | pbuf_free(p);
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| 167 | return NULL;
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| 168 | }
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| 169 | seg->flags = optflags;
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| 170 | seg->next = NULL;
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| 171 | seg->p = p;
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| 172 | seg->len = p->tot_len - optlen;
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| 173 | #if TCP_OVERSIZE_DBGCHECK
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| 174 | seg->oversize_left = 0;
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| 175 | #endif /* TCP_OVERSIZE_DBGCHECK */
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| 176 | #if TCP_CHECKSUM_ON_COPY
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| 177 | seg->chksum = 0;
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| 178 | seg->chksum_swapped = 0;
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| 179 | /* check optflags */
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| 180 | LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
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| 181 | (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
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| 182 | #endif /* TCP_CHECKSUM_ON_COPY */
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| 183 |
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| 184 | /* build TCP header */
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| 185 | if (pbuf_header(p, TCP_HLEN)) {
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| 186 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
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| 187 | TCP_STATS_INC(tcp.err);
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| 188 | tcp_seg_free(seg);
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| 189 | return NULL;
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| 190 | }
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| 191 | seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
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| 192 | seg->tcphdr->src = htons(pcb->local_port);
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| 193 | seg->tcphdr->dest = htons(pcb->remote_port);
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| 194 | seg->tcphdr->seqno = htonl(seqno);
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| 195 | /* ackno is set in tcp_output */
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| 196 | TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
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| 197 | /* wnd and chksum are set in tcp_output */
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| 198 | seg->tcphdr->urgp = 0;
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| 199 | return seg;
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| 200 | }
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| 201 |
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| 202 | /**
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| 203 | * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
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| 204 | *
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| 205 | * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
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| 206 | * there may be extra bytes available at the end.
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| 207 | *
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| 208 | * @param layer flag to define header size.
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| 209 | * @param length size of the pbuf's payload.
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| 210 | * @param max_length maximum usable size of payload+oversize.
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| 211 | * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
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| 212 | * @param pcb The TCP connection that willo enqueue the pbuf.
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| 213 | * @param apiflags API flags given to tcp_write.
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| 214 | * @param first_seg true when this pbuf will be used in the first enqueued segment.
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| 215 | * @param
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| 216 | */
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| 217 | #if TCP_OVERSIZE
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| 218 | static struct pbuf *
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| 219 | tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
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| 220 | u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
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| 221 | u8_t first_seg)
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| 222 | {
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| 223 | struct pbuf *p;
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| 224 | u16_t alloc = length;
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| 225 |
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| 226 | #if LWIP_NETIF_TX_SINGLE_PBUF
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| 227 | LWIP_UNUSED_ARG(max_length);
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| 228 | LWIP_UNUSED_ARG(pcb);
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| 229 | LWIP_UNUSED_ARG(apiflags);
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| 230 | LWIP_UNUSED_ARG(first_seg);
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| 231 | /* always create MSS-sized pbufs */
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| 232 | alloc = max_length;
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| 233 | #else /* LWIP_NETIF_TX_SINGLE_PBUF */
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| 234 | if (length < max_length) {
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| 235 | /* Should we allocate an oversized pbuf, or just the minimum
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| 236 | * length required? If tcp_write is going to be called again
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| 237 | * before this segment is transmitted, we want the oversized
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| 238 | * buffer. If the segment will be transmitted immediately, we can
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| 239 | * save memory by allocating only length. We use a simple
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| 240 | * heuristic based on the following information:
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| 241 | *
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| 242 | * Did the user set TCP_WRITE_FLAG_MORE?
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| 243 | *
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| 244 | * Will the Nagle algorithm defer transmission of this segment?
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| 245 | */
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| 246 | if ((apiflags & TCP_WRITE_FLAG_MORE) ||
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| 247 | (!(pcb->flags & TF_NODELAY) &&
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| 248 | (!first_seg ||
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| 249 | pcb->unsent != NULL ||
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| 250 | pcb->unacked != NULL))) {
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| 251 | alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
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| 252 | }
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| 253 | }
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| 254 | #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
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| 255 | p = pbuf_alloc(layer, alloc, PBUF_RAM);
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| 256 | if (p == NULL) {
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| 257 | return NULL;
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| 258 | }
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| 259 | LWIP_ASSERT("need unchained pbuf", p->next == NULL);
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| 260 | *oversize = p->len - length;
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| 261 | /* trim p->len to the currently used size */
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| 262 | p->len = p->tot_len = length;
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| 263 | return p;
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| 264 | }
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| 265 | #else /* TCP_OVERSIZE */
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| 266 | #define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
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| 267 | #endif /* TCP_OVERSIZE */
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| 268 |
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| 269 | #if TCP_CHECKSUM_ON_COPY
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| 270 | /** Add a checksum of newly added data to the segment */
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| 271 | static void
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| 272 | tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
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| 273 | u8_t *seg_chksum_swapped)
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| 274 | {
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| 275 | u32_t helper;
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| 276 | /* add chksum to old chksum and fold to u16_t */
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| 277 | helper = chksum + *seg_chksum;
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| 278 | chksum = FOLD_U32T(helper);
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| 279 | if ((len & 1) != 0) {
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| 280 | *seg_chksum_swapped = 1 - *seg_chksum_swapped;
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| 281 | chksum = SWAP_BYTES_IN_WORD(chksum);
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| 282 | }
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| 283 | *seg_chksum = chksum;
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| 284 | }
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| 285 | #endif /* TCP_CHECKSUM_ON_COPY */
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| 286 |
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| 287 | /** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
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| 288 | *
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| 289 | * @param pcb the tcp pcb to check for
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| 290 | * @param len length of data to send (checked agains snd_buf)
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| 291 | * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
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| 292 | */
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| 293 | static err_t
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| 294 | tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
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| 295 | {
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| 296 | /* connection is in invalid state for data transmission? */
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| 297 | if ((pcb->state != ESTABLISHED) &&
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| 298 | (pcb->state != CLOSE_WAIT) &&
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| 299 | (pcb->state != SYN_SENT) &&
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| 300 | (pcb->state != SYN_RCVD)) {
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| 301 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
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| 302 | return ERR_CONN;
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| 303 | } else if (len == 0) {
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| 304 | return ERR_OK;
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| 305 | }
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| 306 |
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| 307 | /* fail on too much data */
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| 308 | if (len > pcb->snd_buf) {
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| 309 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
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| 310 | len, pcb->snd_buf));
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| 311 | pcb->flags |= TF_NAGLEMEMERR;
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| 312 | return ERR_MEM;
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| 313 | }
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| 314 |
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| 315 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
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| 316 |
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| 317 | /* If total number of pbufs on the unsent/unacked queues exceeds the
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| 318 | * configured maximum, return an error */
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| 319 | /* check for configured max queuelen and possible overflow */
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| 320 | if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
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| 321 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
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| 322 | pcb->snd_queuelen, TCP_SND_QUEUELEN));
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| 323 | TCP_STATS_INC(tcp.memerr);
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| 324 | pcb->flags |= TF_NAGLEMEMERR;
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| 325 | return ERR_MEM;
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| 326 | }
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| 327 | if (pcb->snd_queuelen != 0) {
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| 328 | LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
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| 329 | pcb->unacked != NULL || pcb->unsent != NULL);
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| 330 | } else {
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| 331 | LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
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| 332 | pcb->unacked == NULL && pcb->unsent == NULL);
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| 333 | }
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| 334 | return ERR_OK;
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| 335 | }
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| 336 |
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| 337 | /**
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| 338 | * Write data for sending (but does not send it immediately).
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| 339 | *
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| 340 | * It waits in the expectation of more data being sent soon (as
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| 341 | * it can send them more efficiently by combining them together).
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| 342 | * To prompt the system to send data now, call tcp_output() after
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| 343 | * calling tcp_write().
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| 344 | *
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| 345 | * @param pcb Protocol control block for the TCP connection to enqueue data for.
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| 346 | * @param arg Pointer to the data to be enqueued for sending.
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| 347 | * @param len Data length in bytes
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| 348 | * @param apiflags combination of following flags :
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| 349 | * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
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| 350 | * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
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| 351 | * @return ERR_OK if enqueued, another err_t on error
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| 352 | */
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| 353 | err_t
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| 354 | tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
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| 355 | {
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| 356 | struct pbuf *concat_p = NULL;
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| 357 | struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
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| 358 | u16_t pos = 0; /* position in 'arg' data */
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| 359 | u16_t queuelen;
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| 360 | u8_t optlen = 0;
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| 361 | u8_t optflags = 0;
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| 362 | #if TCP_OVERSIZE
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| 363 | u16_t oversize = 0;
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| 364 | u16_t oversize_used = 0;
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| 365 | #endif /* TCP_OVERSIZE */
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| 366 | #if TCP_CHECKSUM_ON_COPY
|
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| 367 | u16_t concat_chksum = 0;
|
---|
| 368 | u8_t concat_chksum_swapped = 0;
|
---|
| 369 | u16_t concat_chksummed = 0;
|
---|
| 370 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 371 | err_t err;
|
---|
| 372 | /* don't allocate segments bigger than half the maximum window we ever received */
|
---|
| 373 | u16_t mss_local = LWIP_MIN(pcb->mss, pcb->snd_wnd_max/2);
|
---|
| 374 |
|
---|
| 375 | #if LWIP_NETIF_TX_SINGLE_PBUF
|
---|
| 376 | /* Always copy to try to create single pbufs for TX */
|
---|
| 377 | apiflags |= TCP_WRITE_FLAG_COPY;
|
---|
| 378 | #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
|
---|
| 379 |
|
---|
| 380 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
|
---|
| 381 | (void *)pcb, arg, len, (u16_t)apiflags));
|
---|
| 382 | LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
|
---|
| 383 | arg != NULL, return ERR_ARG;);
|
---|
| 384 |
|
---|
| 385 | err = tcp_write_checks(pcb, len);
|
---|
| 386 | if (err != ERR_OK) {
|
---|
| 387 | return err;
|
---|
| 388 | }
|
---|
| 389 | queuelen = pcb->snd_queuelen;
|
---|
| 390 |
|
---|
| 391 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 392 | if ((pcb->flags & TF_TIMESTAMP)) {
|
---|
| 393 | optflags = TF_SEG_OPTS_TS;
|
---|
| 394 | optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
|
---|
| 395 | }
|
---|
| 396 | #endif /* LWIP_TCP_TIMESTAMPS */
|
---|
| 397 |
|
---|
| 398 |
|
---|
| 399 | /*
|
---|
| 400 | * TCP segmentation is done in three phases with increasing complexity:
|
---|
| 401 | *
|
---|
| 402 | * 1. Copy data directly into an oversized pbuf.
|
---|
| 403 | * 2. Chain a new pbuf to the end of pcb->unsent.
|
---|
| 404 | * 3. Create new segments.
|
---|
| 405 | *
|
---|
| 406 | * We may run out of memory at any point. In that case we must
|
---|
| 407 | * return ERR_MEM and not change anything in pcb. Therefore, all
|
---|
| 408 | * changes are recorded in local variables and committed at the end
|
---|
| 409 | * of the function. Some pcb fields are maintained in local copies:
|
---|
| 410 | *
|
---|
| 411 | * queuelen = pcb->snd_queuelen
|
---|
| 412 | * oversize = pcb->unsent_oversize
|
---|
| 413 | *
|
---|
| 414 | * These variables are set consistently by the phases:
|
---|
| 415 | *
|
---|
| 416 | * seg points to the last segment tampered with.
|
---|
| 417 | *
|
---|
| 418 | * pos records progress as data is segmented.
|
---|
| 419 | */
|
---|
| 420 |
|
---|
| 421 | /* Find the tail of the unsent queue. */
|
---|
| 422 | if (pcb->unsent != NULL) {
|
---|
| 423 | u16_t space;
|
---|
| 424 | u16_t unsent_optlen;
|
---|
| 425 |
|
---|
| 426 | /* @todo: this could be sped up by keeping last_unsent in the pcb */
|
---|
| 427 | for (last_unsent = pcb->unsent; last_unsent->next != NULL;
|
---|
| 428 | last_unsent = last_unsent->next);
|
---|
| 429 |
|
---|
| 430 | /* Usable space at the end of the last unsent segment */
|
---|
| 431 | unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
|
---|
| 432 | space = mss_local - (last_unsent->len + unsent_optlen);
|
---|
| 433 |
|
---|
| 434 | /*
|
---|
| 435 | * Phase 1: Copy data directly into an oversized pbuf.
|
---|
| 436 | *
|
---|
| 437 | * The number of bytes copied is recorded in the oversize_used
|
---|
| 438 | * variable. The actual copying is done at the bottom of the
|
---|
| 439 | * function.
|
---|
| 440 | */
|
---|
| 441 | #if TCP_OVERSIZE
|
---|
| 442 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 443 | /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
|
---|
| 444 | LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
|
---|
| 445 | pcb->unsent_oversize == last_unsent->oversize_left);
|
---|
| 446 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 447 | oversize = pcb->unsent_oversize;
|
---|
| 448 | if (oversize > 0) {
|
---|
| 449 | LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
|
---|
| 450 | seg = last_unsent;
|
---|
| 451 | oversize_used = oversize < len ? oversize : len;
|
---|
| 452 | pos += oversize_used;
|
---|
| 453 | oversize -= oversize_used;
|
---|
| 454 | space -= oversize_used;
|
---|
| 455 | }
|
---|
| 456 | /* now we are either finished or oversize is zero */
|
---|
| 457 | LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
|
---|
| 458 | #endif /* TCP_OVERSIZE */
|
---|
| 459 |
|
---|
| 460 | /*
|
---|
| 461 | * Phase 2: Chain a new pbuf to the end of pcb->unsent.
|
---|
| 462 | *
|
---|
| 463 | * We don't extend segments containing SYN/FIN flags or options
|
---|
| 464 | * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
|
---|
| 465 | * the end.
|
---|
| 466 | */
|
---|
| 467 | if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
|
---|
| 468 | u16_t seglen = space < len - pos ? space : len - pos;
|
---|
| 469 | seg = last_unsent;
|
---|
| 470 |
|
---|
| 471 | /* Create a pbuf with a copy or reference to seglen bytes. We
|
---|
| 472 | * can use PBUF_RAW here since the data appears in the middle of
|
---|
| 473 | * a segment. A header will never be prepended. */
|
---|
| 474 | if (apiflags & TCP_WRITE_FLAG_COPY) {
|
---|
| 475 | /* Data is copied */
|
---|
| 476 | if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
|
---|
| 477 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
|
---|
| 478 | ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
|
---|
| 479 | seglen));
|
---|
| 480 | goto memerr;
|
---|
| 481 | }
|
---|
| 482 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 483 | last_unsent->oversize_left += oversize;
|
---|
| 484 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 485 | TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
|
---|
| 486 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 487 | concat_chksummed += seglen;
|
---|
| 488 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 489 | } else {
|
---|
| 490 | /* Data is not copied */
|
---|
| 491 | if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
|
---|
| 492 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
|
---|
| 493 | ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
---|
| 494 | goto memerr;
|
---|
| 495 | }
|
---|
| 496 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 497 | /* calculate the checksum of nocopy-data */
|
---|
| 498 | tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
|
---|
| 499 | &concat_chksum, &concat_chksum_swapped);
|
---|
| 500 | concat_chksummed += seglen;
|
---|
| 501 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 502 | /* reference the non-volatile payload data */
|
---|
| 503 | concat_p->payload = (u8_t*)arg + pos;
|
---|
| 504 | }
|
---|
| 505 |
|
---|
| 506 | pos += seglen;
|
---|
| 507 | queuelen += pbuf_clen(concat_p);
|
---|
| 508 | }
|
---|
| 509 | } else {
|
---|
| 510 | #if TCP_OVERSIZE
|
---|
| 511 | LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
|
---|
| 512 | pcb->unsent_oversize == 0);
|
---|
| 513 | #endif /* TCP_OVERSIZE */
|
---|
| 514 | }
|
---|
| 515 |
|
---|
| 516 | /*
|
---|
| 517 | * Phase 3: Create new segments.
|
---|
| 518 | *
|
---|
| 519 | * The new segments are chained together in the local 'queue'
|
---|
| 520 | * variable, ready to be appended to pcb->unsent.
|
---|
| 521 | */
|
---|
| 522 | while (pos < len) {
|
---|
| 523 | struct pbuf *p;
|
---|
| 524 | u16_t left = len - pos;
|
---|
| 525 | u16_t max_len = mss_local - optlen;
|
---|
| 526 | u16_t seglen = left > max_len ? max_len : left;
|
---|
| 527 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 528 | u16_t chksum = 0;
|
---|
| 529 | u8_t chksum_swapped = 0;
|
---|
| 530 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 531 |
|
---|
| 532 | if (apiflags & TCP_WRITE_FLAG_COPY) {
|
---|
| 533 | /* If copy is set, memory should be allocated and data copied
|
---|
| 534 | * into pbuf */
|
---|
| 535 | if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
|
---|
| 536 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
|
---|
| 537 | goto memerr;
|
---|
| 538 | }
|
---|
| 539 | LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
|
---|
| 540 | (p->len >= seglen));
|
---|
| 541 | TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
|
---|
| 542 | } else {
|
---|
| 543 | /* Copy is not set: First allocate a pbuf for holding the data.
|
---|
| 544 | * Since the referenced data is available at least until it is
|
---|
| 545 | * sent out on the link (as it has to be ACKed by the remote
|
---|
| 546 | * party) we can safely use PBUF_ROM instead of PBUF_REF here.
|
---|
| 547 | */
|
---|
| 548 | struct pbuf *p2;
|
---|
| 549 | #if TCP_OVERSIZE
|
---|
| 550 | LWIP_ASSERT("oversize == 0", oversize == 0);
|
---|
| 551 | #endif /* TCP_OVERSIZE */
|
---|
| 552 | if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
|
---|
| 553 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
---|
| 554 | goto memerr;
|
---|
| 555 | }
|
---|
| 556 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 557 | /* calculate the checksum of nocopy-data */
|
---|
| 558 | chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
|
---|
| 559 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 560 | /* reference the non-volatile payload data */
|
---|
| 561 | p2->payload = (u8_t*)arg + pos;
|
---|
| 562 |
|
---|
| 563 | /* Second, allocate a pbuf for the headers. */
|
---|
| 564 | if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
---|
| 565 | /* If allocation fails, we have to deallocate the data pbuf as
|
---|
| 566 | * well. */
|
---|
| 567 | pbuf_free(p2);
|
---|
| 568 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for header pbuf\n"));
|
---|
| 569 | goto memerr;
|
---|
| 570 | }
|
---|
| 571 | /* Concatenate the headers and data pbufs together. */
|
---|
| 572 | pbuf_cat(p/*header*/, p2/*data*/);
|
---|
| 573 | }
|
---|
| 574 |
|
---|
| 575 | queuelen += pbuf_clen(p);
|
---|
| 576 |
|
---|
| 577 | /* Now that there are more segments queued, we check again if the
|
---|
| 578 | * length of the queue exceeds the configured maximum or
|
---|
| 579 | * overflows. */
|
---|
| 580 | if ((queuelen > TCP_SND_QUEUELEN) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
|
---|
| 581 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
|
---|
| 582 | pbuf_free(p);
|
---|
| 583 | goto memerr;
|
---|
| 584 | }
|
---|
| 585 |
|
---|
| 586 | if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
|
---|
| 587 | goto memerr;
|
---|
| 588 | }
|
---|
| 589 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 590 | seg->oversize_left = oversize;
|
---|
| 591 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 592 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 593 | seg->chksum = chksum;
|
---|
| 594 | seg->chksum_swapped = chksum_swapped;
|
---|
| 595 | seg->flags |= TF_SEG_DATA_CHECKSUMMED;
|
---|
| 596 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 597 |
|
---|
| 598 | /* first segment of to-be-queued data? */
|
---|
| 599 | if (queue == NULL) {
|
---|
| 600 | queue = seg;
|
---|
| 601 | } else {
|
---|
| 602 | /* Attach the segment to the end of the queued segments */
|
---|
| 603 | LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
|
---|
| 604 | prev_seg->next = seg;
|
---|
| 605 | }
|
---|
| 606 | /* remember last segment of to-be-queued data for next iteration */
|
---|
| 607 | prev_seg = seg;
|
---|
| 608 |
|
---|
| 609 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
|
---|
| 610 | ntohl(seg->tcphdr->seqno),
|
---|
| 611 | ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
|
---|
| 612 |
|
---|
| 613 | pos += seglen;
|
---|
| 614 | }
|
---|
| 615 |
|
---|
| 616 | /*
|
---|
| 617 | * All three segmentation phases were successful. We can commit the
|
---|
| 618 | * transaction.
|
---|
| 619 | */
|
---|
| 620 |
|
---|
| 621 | /*
|
---|
| 622 | * Phase 1: If data has been added to the preallocated tail of
|
---|
| 623 | * last_unsent, we update the length fields of the pbuf chain.
|
---|
| 624 | */
|
---|
| 625 | #if TCP_OVERSIZE
|
---|
| 626 | if (oversize_used > 0) {
|
---|
| 627 | struct pbuf *p;
|
---|
| 628 | /* Bump tot_len of whole chain, len of tail */
|
---|
| 629 | for (p = last_unsent->p; p; p = p->next) {
|
---|
| 630 | p->tot_len += oversize_used;
|
---|
| 631 | if (p->next == NULL) {
|
---|
| 632 | TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
|
---|
| 633 | p->len += oversize_used;
|
---|
| 634 | }
|
---|
| 635 | }
|
---|
| 636 | last_unsent->len += oversize_used;
|
---|
| 637 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 638 | LWIP_ASSERT("last_unsent->oversize_left >= oversize_used",
|
---|
| 639 | last_unsent->oversize_left >= oversize_used);
|
---|
| 640 | last_unsent->oversize_left -= oversize_used;
|
---|
| 641 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 642 | }
|
---|
| 643 | pcb->unsent_oversize = oversize;
|
---|
| 644 | #endif /* TCP_OVERSIZE */
|
---|
| 645 |
|
---|
| 646 | /*
|
---|
| 647 | * Phase 2: concat_p can be concatenated onto last_unsent->p
|
---|
| 648 | */
|
---|
| 649 | if (concat_p != NULL) {
|
---|
| 650 | LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
|
---|
| 651 | (last_unsent != NULL));
|
---|
| 652 | pbuf_cat(last_unsent->p, concat_p);
|
---|
| 653 | last_unsent->len += concat_p->tot_len;
|
---|
| 654 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 655 | if (concat_chksummed) {
|
---|
| 656 | tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
|
---|
| 657 | &last_unsent->chksum_swapped);
|
---|
| 658 | last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
|
---|
| 659 | }
|
---|
| 660 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 661 | }
|
---|
| 662 |
|
---|
| 663 | /*
|
---|
| 664 | * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
|
---|
| 665 | * is harmless
|
---|
| 666 | */
|
---|
| 667 | if (last_unsent == NULL) {
|
---|
| 668 | pcb->unsent = queue;
|
---|
| 669 | } else {
|
---|
| 670 | last_unsent->next = queue;
|
---|
| 671 | }
|
---|
| 672 |
|
---|
| 673 | /*
|
---|
| 674 | * Finally update the pcb state.
|
---|
| 675 | */
|
---|
| 676 | pcb->snd_lbb += len;
|
---|
| 677 | pcb->snd_buf -= len;
|
---|
| 678 | pcb->snd_queuelen = queuelen;
|
---|
| 679 |
|
---|
| 680 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
|
---|
| 681 | pcb->snd_queuelen));
|
---|
| 682 | if (pcb->snd_queuelen != 0) {
|
---|
| 683 | LWIP_ASSERT("tcp_write: valid queue length",
|
---|
| 684 | pcb->unacked != NULL || pcb->unsent != NULL);
|
---|
| 685 | }
|
---|
| 686 |
|
---|
| 687 | /* Set the PSH flag in the last segment that we enqueued. */
|
---|
| 688 | if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
|
---|
| 689 | TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
|
---|
| 690 | }
|
---|
| 691 |
|
---|
| 692 | return ERR_OK;
|
---|
| 693 | memerr:
|
---|
| 694 | pcb->flags |= TF_NAGLEMEMERR;
|
---|
| 695 | TCP_STATS_INC(tcp.memerr);
|
---|
| 696 |
|
---|
| 697 | if (concat_p != NULL) {
|
---|
| 698 | pbuf_free(concat_p);
|
---|
| 699 | }
|
---|
| 700 | if (queue != NULL) {
|
---|
| 701 | tcp_segs_free(queue);
|
---|
| 702 | }
|
---|
| 703 | if (pcb->snd_queuelen != 0) {
|
---|
| 704 | LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
|
---|
| 705 | pcb->unsent != NULL);
|
---|
| 706 | }
|
---|
| 707 | LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
|
---|
| 708 | return ERR_MEM;
|
---|
| 709 | }
|
---|
| 710 |
|
---|
| 711 | /**
|
---|
| 712 | * Enqueue TCP options for transmission.
|
---|
| 713 | *
|
---|
| 714 | * Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
|
---|
| 715 | *
|
---|
| 716 | * @param pcb Protocol control block for the TCP connection.
|
---|
| 717 | * @param flags TCP header flags to set in the outgoing segment.
|
---|
| 718 | * @param optdata pointer to TCP options, or NULL.
|
---|
| 719 | * @param optlen length of TCP options in bytes.
|
---|
| 720 | */
|
---|
| 721 | err_t
|
---|
| 722 | tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
|
---|
| 723 | {
|
---|
| 724 | struct pbuf *p;
|
---|
| 725 | struct tcp_seg *seg;
|
---|
| 726 | u8_t optflags = 0;
|
---|
| 727 | u8_t optlen = 0;
|
---|
| 728 |
|
---|
| 729 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
|
---|
| 730 |
|
---|
| 731 | LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
|
---|
| 732 | (flags & (TCP_SYN | TCP_FIN)) != 0);
|
---|
| 733 |
|
---|
| 734 | /* check for configured max queuelen and possible overflow */
|
---|
| 735 | if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
|
---|
| 736 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
|
---|
| 737 | pcb->snd_queuelen, TCP_SND_QUEUELEN));
|
---|
| 738 | TCP_STATS_INC(tcp.memerr);
|
---|
| 739 | pcb->flags |= TF_NAGLEMEMERR;
|
---|
| 740 | return ERR_MEM;
|
---|
| 741 | }
|
---|
| 742 |
|
---|
| 743 | if (flags & TCP_SYN) {
|
---|
| 744 | optflags = TF_SEG_OPTS_MSS;
|
---|
| 745 | }
|
---|
| 746 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 747 | if ((pcb->flags & TF_TIMESTAMP)) {
|
---|
| 748 | optflags |= TF_SEG_OPTS_TS;
|
---|
| 749 | }
|
---|
| 750 | #endif /* LWIP_TCP_TIMESTAMPS */
|
---|
| 751 | optlen = LWIP_TCP_OPT_LENGTH(optflags);
|
---|
| 752 |
|
---|
| 753 | /* tcp_enqueue_flags is always called with either SYN or FIN in flags.
|
---|
| 754 | * We need one available snd_buf byte to do that.
|
---|
| 755 | * This means we can't send FIN while snd_buf==0. A better fix would be to
|
---|
| 756 | * not include SYN and FIN sequence numbers in the snd_buf count. */
|
---|
| 757 | if (pcb->snd_buf == 0) {
|
---|
| 758 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: no send buffer available\n"));
|
---|
| 759 | TCP_STATS_INC(tcp.memerr);
|
---|
| 760 | return ERR_MEM;
|
---|
| 761 | }
|
---|
| 762 |
|
---|
| 763 | /* Allocate pbuf with room for TCP header + options */
|
---|
| 764 | if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
---|
| 765 | pcb->flags |= TF_NAGLEMEMERR;
|
---|
| 766 | TCP_STATS_INC(tcp.memerr);
|
---|
| 767 | return ERR_MEM;
|
---|
| 768 | }
|
---|
| 769 | LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
|
---|
| 770 | (p->len >= optlen));
|
---|
| 771 |
|
---|
| 772 | /* Allocate memory for tcp_seg, and fill in fields. */
|
---|
| 773 | if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
|
---|
| 774 | pcb->flags |= TF_NAGLEMEMERR;
|
---|
| 775 | TCP_STATS_INC(tcp.memerr);
|
---|
| 776 | return ERR_MEM;
|
---|
| 777 | }
|
---|
| 778 | LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
|
---|
| 779 | LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
|
---|
| 780 |
|
---|
| 781 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
|
---|
| 782 | ("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
|
---|
| 783 | ntohl(seg->tcphdr->seqno),
|
---|
| 784 | ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
|
---|
| 785 | (u16_t)flags));
|
---|
| 786 |
|
---|
| 787 | /* Now append seg to pcb->unsent queue */
|
---|
| 788 | if (pcb->unsent == NULL) {
|
---|
| 789 | pcb->unsent = seg;
|
---|
| 790 | } else {
|
---|
| 791 | struct tcp_seg *useg;
|
---|
| 792 | for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
|
---|
| 793 | useg->next = seg;
|
---|
| 794 | }
|
---|
| 795 | #if TCP_OVERSIZE
|
---|
| 796 | /* The new unsent tail has no space */
|
---|
| 797 | pcb->unsent_oversize = 0;
|
---|
| 798 | #endif /* TCP_OVERSIZE */
|
---|
| 799 |
|
---|
| 800 | /* SYN and FIN bump the sequence number */
|
---|
| 801 | if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
|
---|
| 802 | pcb->snd_lbb++;
|
---|
| 803 | /* optlen does not influence snd_buf */
|
---|
| 804 | pcb->snd_buf--;
|
---|
| 805 | }
|
---|
| 806 | if (flags & TCP_FIN) {
|
---|
| 807 | pcb->flags |= TF_FIN;
|
---|
| 808 | }
|
---|
| 809 |
|
---|
| 810 | /* update number of segments on the queues */
|
---|
| 811 | pcb->snd_queuelen += pbuf_clen(seg->p);
|
---|
| 812 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
|
---|
| 813 | if (pcb->snd_queuelen != 0) {
|
---|
| 814 | LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
|
---|
| 815 | pcb->unacked != NULL || pcb->unsent != NULL);
|
---|
| 816 | }
|
---|
| 817 |
|
---|
| 818 | return ERR_OK;
|
---|
| 819 | }
|
---|
| 820 |
|
---|
| 821 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 822 | /* Build a timestamp option (12 bytes long) at the specified options pointer)
|
---|
| 823 | *
|
---|
| 824 | * @param pcb tcp_pcb
|
---|
| 825 | * @param opts option pointer where to store the timestamp option
|
---|
| 826 | */
|
---|
| 827 | static void
|
---|
| 828 | tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
|
---|
| 829 | {
|
---|
| 830 | /* Pad with two NOP options to make everything nicely aligned */
|
---|
| 831 | opts[0] = PP_HTONL(0x0101080A);
|
---|
| 832 | opts[1] = htonl(sys_now());
|
---|
| 833 | opts[2] = htonl(pcb->ts_recent);
|
---|
| 834 | }
|
---|
| 835 | #endif
|
---|
| 836 |
|
---|
| 837 | /** Send an ACK without data.
|
---|
| 838 | *
|
---|
| 839 | * @param pcb Protocol control block for the TCP connection to send the ACK
|
---|
| 840 | */
|
---|
| 841 | err_t
|
---|
| 842 | tcp_send_empty_ack(struct tcp_pcb *pcb)
|
---|
| 843 | {
|
---|
| 844 | struct pbuf *p;
|
---|
| 845 | struct tcp_hdr *tcphdr;
|
---|
| 846 | u8_t optlen = 0;
|
---|
| 847 |
|
---|
| 848 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 849 | if (pcb->flags & TF_TIMESTAMP) {
|
---|
| 850 | optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
|
---|
| 851 | }
|
---|
| 852 | #endif
|
---|
| 853 |
|
---|
| 854 | p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
|
---|
| 855 | if (p == NULL) {
|
---|
| 856 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
|
---|
| 857 | return ERR_BUF;
|
---|
| 858 | }
|
---|
| 859 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 860 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
|
---|
| 861 | ("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
|
---|
| 862 | /* remove ACK flags from the PCB, as we send an empty ACK now */
|
---|
| 863 | pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 864 |
|
---|
| 865 | /* NB. MSS option is only sent on SYNs, so ignore it here */
|
---|
| 866 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 867 | pcb->ts_lastacksent = pcb->rcv_nxt;
|
---|
| 868 |
|
---|
| 869 | if (pcb->flags & TF_TIMESTAMP) {
|
---|
| 870 | tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
|
---|
| 871 | }
|
---|
| 872 | #endif
|
---|
| 873 |
|
---|
| 874 | #if CHECKSUM_GEN_TCP
|
---|
| 875 | tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
|
---|
| 876 | IP_PROTO_TCP, p->tot_len);
|
---|
| 877 | #endif
|
---|
| 878 | #if LWIP_NETIF_HWADDRHINT
|
---|
| 879 | ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
|
---|
| 880 | IP_PROTO_TCP, &(pcb->addr_hint));
|
---|
| 881 | #else /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 882 | ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
|
---|
| 883 | IP_PROTO_TCP);
|
---|
| 884 | #endif /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 885 | pbuf_free(p);
|
---|
| 886 |
|
---|
| 887 | return ERR_OK;
|
---|
| 888 | }
|
---|
| 889 |
|
---|
| 890 | /**
|
---|
| 891 | * Find out what we can send and send it
|
---|
| 892 | *
|
---|
| 893 | * @param pcb Protocol control block for the TCP connection to send data
|
---|
| 894 | * @return ERR_OK if data has been sent or nothing to send
|
---|
| 895 | * another err_t on error
|
---|
| 896 | */
|
---|
| 897 | err_t
|
---|
| 898 | tcp_output(struct tcp_pcb *pcb)
|
---|
| 899 | {
|
---|
| 900 | struct tcp_seg *seg, *useg;
|
---|
| 901 | u32_t wnd, snd_nxt;
|
---|
| 902 | #if TCP_CWND_DEBUG
|
---|
| 903 | s16_t i = 0;
|
---|
| 904 | #endif /* TCP_CWND_DEBUG */
|
---|
| 905 |
|
---|
| 906 | /* pcb->state LISTEN not allowed here */
|
---|
| 907 | LWIP_ASSERT("don't call tcp_output for listen-pcbs",
|
---|
| 908 | pcb->state != LISTEN);
|
---|
| 909 |
|
---|
| 910 | /* First, check if we are invoked by the TCP input processing
|
---|
| 911 | code. If so, we do not output anything. Instead, we rely on the
|
---|
| 912 | input processing code to call us when input processing is done
|
---|
| 913 | with. */
|
---|
| 914 | if (tcp_input_pcb == pcb) {
|
---|
| 915 | return ERR_OK;
|
---|
| 916 | }
|
---|
| 917 |
|
---|
| 918 | wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
|
---|
| 919 |
|
---|
| 920 | seg = pcb->unsent;
|
---|
| 921 |
|
---|
| 922 | /* If the TF_ACK_NOW flag is set and no data will be sent (either
|
---|
| 923 | * because the ->unsent queue is empty or because the window does
|
---|
| 924 | * not allow it), construct an empty ACK segment and send it.
|
---|
| 925 | *
|
---|
| 926 | * If data is to be sent, we will just piggyback the ACK (see below).
|
---|
| 927 | */
|
---|
| 928 | if (pcb->flags & TF_ACK_NOW &&
|
---|
| 929 | (seg == NULL ||
|
---|
| 930 | ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
|
---|
| 931 | return tcp_send_empty_ack(pcb);
|
---|
| 932 | }
|
---|
| 933 |
|
---|
| 934 | /* useg should point to last segment on unacked queue */
|
---|
| 935 | useg = pcb->unacked;
|
---|
| 936 | if (useg != NULL) {
|
---|
| 937 | for (; useg->next != NULL; useg = useg->next);
|
---|
| 938 | }
|
---|
| 939 |
|
---|
| 940 | #if TCP_OUTPUT_DEBUG
|
---|
| 941 | if (seg == NULL) {
|
---|
| 942 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
|
---|
| 943 | (void*)pcb->unsent));
|
---|
| 944 | }
|
---|
| 945 | #endif /* TCP_OUTPUT_DEBUG */
|
---|
| 946 | #if TCP_CWND_DEBUG
|
---|
| 947 | if (seg == NULL) {
|
---|
| 948 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
|
---|
| 949 | ", cwnd %"U16_F", wnd %"U32_F
|
---|
| 950 | ", seg == NULL, ack %"U32_F"\n",
|
---|
| 951 | pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
|
---|
| 952 | } else {
|
---|
| 953 | LWIP_DEBUGF(TCP_CWND_DEBUG,
|
---|
| 954 | ("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
|
---|
| 955 | ", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
|
---|
| 956 | pcb->snd_wnd, pcb->cwnd, wnd,
|
---|
| 957 | ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
|
---|
| 958 | ntohl(seg->tcphdr->seqno), pcb->lastack));
|
---|
| 959 | }
|
---|
| 960 | #endif /* TCP_CWND_DEBUG */
|
---|
| 961 | /* data available and window allows it to be sent? */
|
---|
| 962 | while (seg != NULL &&
|
---|
| 963 | ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
|
---|
| 964 | LWIP_ASSERT("RST not expected here!",
|
---|
| 965 | (TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
|
---|
| 966 | /* Stop sending if the nagle algorithm would prevent it
|
---|
| 967 | * Don't stop:
|
---|
| 968 | * - if tcp_write had a memory error before (prevent delayed ACK timeout) or
|
---|
| 969 | * - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
|
---|
| 970 | * either seg->next != NULL or pcb->unacked == NULL;
|
---|
| 971 | * RST is no sent using tcp_write/tcp_output.
|
---|
| 972 | */
|
---|
| 973 | if((tcp_do_output_nagle(pcb) == 0) &&
|
---|
| 974 | ((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)){
|
---|
| 975 | break;
|
---|
| 976 | }
|
---|
| 977 | #if TCP_CWND_DEBUG
|
---|
| 978 | 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",
|
---|
| 979 | pcb->snd_wnd, pcb->cwnd, wnd,
|
---|
| 980 | ntohl(seg->tcphdr->seqno) + seg->len -
|
---|
| 981 | pcb->lastack,
|
---|
| 982 | ntohl(seg->tcphdr->seqno), pcb->lastack, i));
|
---|
| 983 | ++i;
|
---|
| 984 | #endif /* TCP_CWND_DEBUG */
|
---|
| 985 |
|
---|
| 986 | pcb->unsent = seg->next;
|
---|
| 987 |
|
---|
| 988 | if (pcb->state != SYN_SENT) {
|
---|
| 989 | TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
|
---|
| 990 | pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 991 | }
|
---|
| 992 |
|
---|
| 993 | tcp_output_segment(seg, pcb);
|
---|
| 994 | snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
|
---|
| 995 | if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
---|
| 996 | pcb->snd_nxt = snd_nxt;
|
---|
| 997 | }
|
---|
| 998 | /* put segment on unacknowledged list if length > 0 */
|
---|
| 999 | if (TCP_TCPLEN(seg) > 0) {
|
---|
| 1000 | seg->next = NULL;
|
---|
| 1001 | /* unacked list is empty? */
|
---|
| 1002 | if (pcb->unacked == NULL) {
|
---|
| 1003 | pcb->unacked = seg;
|
---|
| 1004 | useg = seg;
|
---|
| 1005 | /* unacked list is not empty? */
|
---|
| 1006 | } else {
|
---|
| 1007 | /* In the case of fast retransmit, the packet should not go to the tail
|
---|
| 1008 | * of the unacked queue, but rather somewhere before it. We need to check for
|
---|
| 1009 | * this case. -STJ Jul 27, 2004 */
|
---|
| 1010 | if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
|
---|
| 1011 | /* add segment to before tail of unacked list, keeping the list sorted */
|
---|
| 1012 | struct tcp_seg **cur_seg = &(pcb->unacked);
|
---|
| 1013 | while (*cur_seg &&
|
---|
| 1014 | TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
|
---|
| 1015 | cur_seg = &((*cur_seg)->next );
|
---|
| 1016 | }
|
---|
| 1017 | seg->next = (*cur_seg);
|
---|
| 1018 | (*cur_seg) = seg;
|
---|
| 1019 | } else {
|
---|
| 1020 | /* add segment to tail of unacked list */
|
---|
| 1021 | useg->next = seg;
|
---|
| 1022 | useg = useg->next;
|
---|
| 1023 | }
|
---|
| 1024 | }
|
---|
| 1025 | /* do not queue empty segments on the unacked list */
|
---|
| 1026 | } else {
|
---|
| 1027 | tcp_seg_free(seg);
|
---|
| 1028 | }
|
---|
| 1029 | seg = pcb->unsent;
|
---|
| 1030 | }
|
---|
| 1031 | #if TCP_OVERSIZE
|
---|
| 1032 | if (pcb->unsent == NULL) {
|
---|
| 1033 | /* last unsent has been removed, reset unsent_oversize */
|
---|
| 1034 | pcb->unsent_oversize = 0;
|
---|
| 1035 | }
|
---|
| 1036 | #endif /* TCP_OVERSIZE */
|
---|
| 1037 |
|
---|
| 1038 | pcb->flags &= ~TF_NAGLEMEMERR;
|
---|
| 1039 | return ERR_OK;
|
---|
| 1040 | }
|
---|
| 1041 |
|
---|
| 1042 | /**
|
---|
| 1043 | * Called by tcp_output() to actually send a TCP segment over IP.
|
---|
| 1044 | *
|
---|
| 1045 | * @param seg the tcp_seg to send
|
---|
| 1046 | * @param pcb the tcp_pcb for the TCP connection used to send the segment
|
---|
| 1047 | */
|
---|
| 1048 | static void
|
---|
| 1049 | tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
|
---|
| 1050 | {
|
---|
| 1051 | u16_t len;
|
---|
| 1052 | struct netif *netif;
|
---|
| 1053 | u32_t *opts;
|
---|
| 1054 |
|
---|
| 1055 | /** @bug Exclude retransmitted segments from this count. */
|
---|
| 1056 | snmp_inc_tcpoutsegs();
|
---|
| 1057 |
|
---|
| 1058 | /* The TCP header has already been constructed, but the ackno and
|
---|
| 1059 | wnd fields remain. */
|
---|
| 1060 | seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
|
---|
| 1061 |
|
---|
| 1062 | /* advertise our receive window size in this TCP segment */
|
---|
| 1063 | seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
|
---|
| 1064 |
|
---|
| 1065 | pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
|
---|
| 1066 |
|
---|
| 1067 | /* Add any requested options. NB MSS option is only set on SYN
|
---|
| 1068 | packets, so ignore it here */
|
---|
| 1069 | opts = (u32_t *)(void *)(seg->tcphdr + 1);
|
---|
| 1070 | if (seg->flags & TF_SEG_OPTS_MSS) {
|
---|
| 1071 | u16_t mss;
|
---|
| 1072 | #if TCP_CALCULATE_EFF_SEND_MSS
|
---|
| 1073 | mss = tcp_eff_send_mss(TCP_MSS, &pcb->remote_ip);
|
---|
| 1074 | #else /* TCP_CALCULATE_EFF_SEND_MSS */
|
---|
| 1075 | mss = TCP_MSS;
|
---|
| 1076 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */
|
---|
| 1077 | *opts = TCP_BUILD_MSS_OPTION(mss);
|
---|
| 1078 | opts += 1;
|
---|
| 1079 | }
|
---|
| 1080 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 1081 | pcb->ts_lastacksent = pcb->rcv_nxt;
|
---|
| 1082 |
|
---|
| 1083 | if (seg->flags & TF_SEG_OPTS_TS) {
|
---|
| 1084 | tcp_build_timestamp_option(pcb, opts);
|
---|
| 1085 | opts += 3;
|
---|
| 1086 | }
|
---|
| 1087 | #endif
|
---|
| 1088 |
|
---|
| 1089 | /* Set retransmission timer running if it is not currently enabled
|
---|
| 1090 | This must be set before checking the route. */
|
---|
| 1091 | if (pcb->rtime == -1) {
|
---|
| 1092 | pcb->rtime = 0;
|
---|
| 1093 | }
|
---|
| 1094 |
|
---|
| 1095 | /* If we don't have a local IP address, we get one by
|
---|
| 1096 | calling ip_route(). */
|
---|
| 1097 | if (ip_addr_isany(&(pcb->local_ip))) {
|
---|
| 1098 | netif = ip_route(&(pcb->remote_ip));
|
---|
| 1099 | if (netif == NULL) {
|
---|
| 1100 | return;
|
---|
| 1101 | }
|
---|
| 1102 | ip_addr_copy(pcb->local_ip, netif->ip_addr);
|
---|
| 1103 | }
|
---|
| 1104 |
|
---|
| 1105 | if (pcb->rttest == 0) {
|
---|
| 1106 | pcb->rttest = tcp_ticks;
|
---|
| 1107 | pcb->rtseq = ntohl(seg->tcphdr->seqno);
|
---|
| 1108 |
|
---|
| 1109 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
|
---|
| 1110 | }
|
---|
| 1111 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
|
---|
| 1112 | htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
|
---|
| 1113 | seg->len));
|
---|
| 1114 |
|
---|
| 1115 | len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
|
---|
| 1116 |
|
---|
| 1117 | seg->p->len -= len;
|
---|
| 1118 | seg->p->tot_len -= len;
|
---|
| 1119 |
|
---|
| 1120 | seg->p->payload = seg->tcphdr;
|
---|
| 1121 |
|
---|
| 1122 | seg->tcphdr->chksum = 0;
|
---|
| 1123 | #if CHECKSUM_GEN_TCP
|
---|
| 1124 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 1125 | {
|
---|
| 1126 | u32_t acc;
|
---|
| 1127 | #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
---|
| 1128 | u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
|
---|
| 1129 | &(pcb->remote_ip),
|
---|
| 1130 | IP_PROTO_TCP, seg->p->tot_len);
|
---|
| 1131 | #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
---|
| 1132 | if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
|
---|
| 1133 | LWIP_ASSERT("data included but not checksummed",
|
---|
| 1134 | seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
|
---|
| 1135 | }
|
---|
| 1136 |
|
---|
| 1137 | /* rebuild TCP header checksum (TCP header changes for retransmissions!) */
|
---|
| 1138 | acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
|
---|
| 1139 | &(pcb->remote_ip),
|
---|
| 1140 | IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
|
---|
| 1141 | /* add payload checksum */
|
---|
| 1142 | if (seg->chksum_swapped) {
|
---|
| 1143 | seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
|
---|
| 1144 | seg->chksum_swapped = 0;
|
---|
| 1145 | }
|
---|
| 1146 | acc += (u16_t)~(seg->chksum);
|
---|
| 1147 | seg->tcphdr->chksum = FOLD_U32T(acc);
|
---|
| 1148 | #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
---|
| 1149 | if (chksum_slow != seg->tcphdr->chksum) {
|
---|
| 1150 | LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING,
|
---|
| 1151 | ("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
|
---|
| 1152 | seg->tcphdr->chksum, chksum_slow));
|
---|
| 1153 | seg->tcphdr->chksum = chksum_slow;
|
---|
| 1154 | }
|
---|
| 1155 | #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
---|
| 1156 | }
|
---|
| 1157 | #else /* TCP_CHECKSUM_ON_COPY */
|
---|
| 1158 | seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
|
---|
| 1159 | &(pcb->remote_ip),
|
---|
| 1160 | IP_PROTO_TCP, seg->p->tot_len);
|
---|
| 1161 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 1162 | #endif /* CHECKSUM_GEN_TCP */
|
---|
| 1163 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1164 |
|
---|
| 1165 | #if LWIP_NETIF_HWADDRHINT
|
---|
| 1166 | ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
|
---|
| 1167 | IP_PROTO_TCP, &(pcb->addr_hint));
|
---|
| 1168 | #else /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1169 | ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
|
---|
| 1170 | IP_PROTO_TCP);
|
---|
| 1171 | #endif /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1172 | }
|
---|
| 1173 |
|
---|
| 1174 | /**
|
---|
| 1175 | * Send a TCP RESET packet (empty segment with RST flag set) either to
|
---|
| 1176 | * abort a connection or to show that there is no matching local connection
|
---|
| 1177 | * for a received segment.
|
---|
| 1178 | *
|
---|
| 1179 | * Called by tcp_abort() (to abort a local connection), tcp_input() (if no
|
---|
| 1180 | * matching local pcb was found), tcp_listen_input() (if incoming segment
|
---|
| 1181 | * has ACK flag set) and tcp_process() (received segment in the wrong state)
|
---|
| 1182 | *
|
---|
| 1183 | * Since a RST segment is in most cases not sent for an active connection,
|
---|
| 1184 | * tcp_rst() has a number of arguments that are taken from a tcp_pcb for
|
---|
| 1185 | * most other segment output functions.
|
---|
| 1186 | *
|
---|
| 1187 | * @param seqno the sequence number to use for the outgoing segment
|
---|
| 1188 | * @param ackno the acknowledge number to use for the outgoing segment
|
---|
| 1189 | * @param local_ip the local IP address to send the segment from
|
---|
| 1190 | * @param remote_ip the remote IP address to send the segment to
|
---|
| 1191 | * @param local_port the local TCP port to send the segment from
|
---|
| 1192 | * @param remote_port the remote TCP port to send the segment to
|
---|
| 1193 | */
|
---|
| 1194 | void
|
---|
| 1195 | tcp_rst(u32_t seqno, u32_t ackno,
|
---|
| 1196 | ip_addr_t *local_ip, ip_addr_t *remote_ip,
|
---|
| 1197 | u16_t local_port, u16_t remote_port)
|
---|
| 1198 | {
|
---|
| 1199 | struct pbuf *p;
|
---|
| 1200 | struct tcp_hdr *tcphdr;
|
---|
| 1201 | p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
|
---|
| 1202 | if (p == NULL) {
|
---|
| 1203 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
|
---|
| 1204 | return;
|
---|
| 1205 | }
|
---|
| 1206 | LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
|
---|
| 1207 | (p->len >= sizeof(struct tcp_hdr)));
|
---|
| 1208 |
|
---|
| 1209 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1210 | tcphdr->src = htons(local_port);
|
---|
| 1211 | tcphdr->dest = htons(remote_port);
|
---|
| 1212 | tcphdr->seqno = htonl(seqno);
|
---|
| 1213 | tcphdr->ackno = htonl(ackno);
|
---|
| 1214 | TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST | TCP_ACK);
|
---|
| 1215 | tcphdr->wnd = PP_HTONS(TCP_WND);
|
---|
| 1216 | tcphdr->chksum = 0;
|
---|
| 1217 | tcphdr->urgp = 0;
|
---|
| 1218 |
|
---|
| 1219 | #if CHECKSUM_GEN_TCP
|
---|
| 1220 | tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
|
---|
| 1221 | IP_PROTO_TCP, p->tot_len);
|
---|
| 1222 | #endif
|
---|
| 1223 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1224 | snmp_inc_tcpoutrsts();
|
---|
| 1225 | /* Send output with hardcoded TTL since we have no access to the pcb */
|
---|
| 1226 | ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
|
---|
| 1227 | pbuf_free(p);
|
---|
| 1228 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
|
---|
| 1229 | }
|
---|
| 1230 |
|
---|
| 1231 | /**
|
---|
| 1232 | * Requeue all unacked segments for retransmission
|
---|
| 1233 | *
|
---|
| 1234 | * Called by tcp_slowtmr() for slow retransmission.
|
---|
| 1235 | *
|
---|
| 1236 | * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
---|
| 1237 | */
|
---|
| 1238 | void
|
---|
| 1239 | tcp_rexmit_rto(struct tcp_pcb *pcb)
|
---|
| 1240 | {
|
---|
| 1241 | struct tcp_seg *seg;
|
---|
| 1242 |
|
---|
| 1243 | if (pcb->unacked == NULL) {
|
---|
| 1244 | return;
|
---|
| 1245 | }
|
---|
| 1246 |
|
---|
| 1247 | /* Move all unacked segments to the head of the unsent queue */
|
---|
| 1248 | for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
|
---|
| 1249 | /* concatenate unsent queue after unacked queue */
|
---|
| 1250 | seg->next = pcb->unsent;
|
---|
| 1251 | /* unsent queue is the concatenated queue (of unacked, unsent) */
|
---|
| 1252 | pcb->unsent = pcb->unacked;
|
---|
| 1253 | /* unacked queue is now empty */
|
---|
| 1254 | pcb->unacked = NULL;
|
---|
| 1255 | /* last unsent hasn't changed, no need to reset unsent_oversize */
|
---|
| 1256 |
|
---|
| 1257 | /* increment number of retransmissions */
|
---|
| 1258 | ++pcb->nrtx;
|
---|
| 1259 |
|
---|
| 1260 | /* Don't take any RTT measurements after retransmitting. */
|
---|
| 1261 | pcb->rttest = 0;
|
---|
| 1262 |
|
---|
| 1263 | /* Do the actual retransmission */
|
---|
| 1264 | tcp_output(pcb);
|
---|
| 1265 | }
|
---|
| 1266 |
|
---|
| 1267 | /**
|
---|
| 1268 | * Requeue the first unacked segment for retransmission
|
---|
| 1269 | *
|
---|
| 1270 | * Called by tcp_receive() for fast retramsmit.
|
---|
| 1271 | *
|
---|
| 1272 | * @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
---|
| 1273 | */
|
---|
| 1274 | void
|
---|
| 1275 | tcp_rexmit(struct tcp_pcb *pcb)
|
---|
| 1276 | {
|
---|
| 1277 | struct tcp_seg *seg;
|
---|
| 1278 | struct tcp_seg **cur_seg;
|
---|
| 1279 |
|
---|
| 1280 | if (pcb->unacked == NULL) {
|
---|
| 1281 | return;
|
---|
| 1282 | }
|
---|
| 1283 |
|
---|
| 1284 | /* Move the first unacked segment to the unsent queue */
|
---|
| 1285 | /* Keep the unsent queue sorted. */
|
---|
| 1286 | seg = pcb->unacked;
|
---|
| 1287 | pcb->unacked = seg->next;
|
---|
| 1288 |
|
---|
| 1289 | cur_seg = &(pcb->unsent);
|
---|
| 1290 | while (*cur_seg &&
|
---|
| 1291 | TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
|
---|
| 1292 | cur_seg = &((*cur_seg)->next );
|
---|
| 1293 | }
|
---|
| 1294 | seg->next = *cur_seg;
|
---|
| 1295 | *cur_seg = seg;
|
---|
| 1296 | #if TCP_OVERSIZE
|
---|
| 1297 | if (seg->next == NULL) {
|
---|
| 1298 | /* the retransmitted segment is last in unsent, so reset unsent_oversize */
|
---|
| 1299 | pcb->unsent_oversize = 0;
|
---|
| 1300 | }
|
---|
| 1301 | #endif /* TCP_OVERSIZE */
|
---|
| 1302 |
|
---|
| 1303 | ++pcb->nrtx;
|
---|
| 1304 |
|
---|
| 1305 | /* Don't take any rtt measurements after retransmitting. */
|
---|
| 1306 | pcb->rttest = 0;
|
---|
| 1307 |
|
---|
| 1308 | /* Do the actual retransmission. */
|
---|
| 1309 | snmp_inc_tcpretranssegs();
|
---|
| 1310 | /* No need to call tcp_output: we are always called from tcp_input()
|
---|
| 1311 | and thus tcp_output directly returns. */
|
---|
| 1312 | }
|
---|
| 1313 |
|
---|
| 1314 |
|
---|
| 1315 | /**
|
---|
| 1316 | * Handle retransmission after three dupacks received
|
---|
| 1317 | *
|
---|
| 1318 | * @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
---|
| 1319 | */
|
---|
| 1320 | void
|
---|
| 1321 | tcp_rexmit_fast(struct tcp_pcb *pcb)
|
---|
| 1322 | {
|
---|
| 1323 | if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
|
---|
| 1324 | /* This is fast retransmit. Retransmit the first unacked segment. */
|
---|
| 1325 | LWIP_DEBUGF(TCP_FR_DEBUG,
|
---|
| 1326 | ("tcp_receive: dupacks %"U16_F" (%"U32_F
|
---|
| 1327 | "), fast retransmit %"U32_F"\n",
|
---|
| 1328 | (u16_t)pcb->dupacks, pcb->lastack,
|
---|
| 1329 | ntohl(pcb->unacked->tcphdr->seqno)));
|
---|
| 1330 | tcp_rexmit(pcb);
|
---|
| 1331 |
|
---|
| 1332 | /* Set ssthresh to half of the minimum of the current
|
---|
| 1333 | * cwnd and the advertised window */
|
---|
| 1334 | if (pcb->cwnd > pcb->snd_wnd) {
|
---|
| 1335 | pcb->ssthresh = pcb->snd_wnd / 2;
|
---|
| 1336 | } else {
|
---|
| 1337 | pcb->ssthresh = pcb->cwnd / 2;
|
---|
| 1338 | }
|
---|
| 1339 |
|
---|
| 1340 | /* The minimum value for ssthresh should be 2 MSS */
|
---|
| 1341 | if (pcb->ssthresh < 2*pcb->mss) {
|
---|
| 1342 | LWIP_DEBUGF(TCP_FR_DEBUG,
|
---|
| 1343 | ("tcp_receive: The minimum value for ssthresh %"U16_F
|
---|
| 1344 | " should be min 2 mss %"U16_F"...\n",
|
---|
| 1345 | pcb->ssthresh, 2*pcb->mss));
|
---|
| 1346 | pcb->ssthresh = 2*pcb->mss;
|
---|
| 1347 | }
|
---|
| 1348 |
|
---|
| 1349 | pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
|
---|
| 1350 | pcb->flags |= TF_INFR;
|
---|
| 1351 | }
|
---|
| 1352 | }
|
---|
| 1353 |
|
---|
| 1354 |
|
---|
| 1355 | /**
|
---|
| 1356 | * Send keepalive packets to keep a connection active although
|
---|
| 1357 | * no data is sent over it.
|
---|
| 1358 | *
|
---|
| 1359 | * Called by tcp_slowtmr()
|
---|
| 1360 | *
|
---|
| 1361 | * @param pcb the tcp_pcb for which to send a keepalive packet
|
---|
| 1362 | */
|
---|
| 1363 | void
|
---|
| 1364 | tcp_keepalive(struct tcp_pcb *pcb)
|
---|
| 1365 | {
|
---|
| 1366 | struct pbuf *p;
|
---|
| 1367 | struct tcp_hdr *tcphdr;
|
---|
| 1368 |
|
---|
| 1369 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
|
---|
| 1370 | ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
|
---|
| 1371 | ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
|
---|
| 1372 |
|
---|
| 1373 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
---|
| 1374 | tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
|
---|
| 1375 |
|
---|
| 1376 | p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
|
---|
| 1377 | if(p == NULL) {
|
---|
| 1378 | LWIP_DEBUGF(TCP_DEBUG,
|
---|
| 1379 | ("tcp_keepalive: could not allocate memory for pbuf\n"));
|
---|
| 1380 | return;
|
---|
| 1381 | }
|
---|
| 1382 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1383 |
|
---|
| 1384 | #if CHECKSUM_GEN_TCP
|
---|
| 1385 | tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
|
---|
| 1386 | IP_PROTO_TCP, p->tot_len);
|
---|
| 1387 | #endif
|
---|
| 1388 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1389 |
|
---|
| 1390 | /* Send output to IP */
|
---|
| 1391 | #if LWIP_NETIF_HWADDRHINT
|
---|
| 1392 | ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
|
---|
| 1393 | &(pcb->addr_hint));
|
---|
| 1394 | #else /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1395 | ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
|
---|
| 1396 | #endif /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1397 |
|
---|
| 1398 | pbuf_free(p);
|
---|
| 1399 |
|
---|
| 1400 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
|
---|
| 1401 | pcb->snd_nxt - 1, pcb->rcv_nxt));
|
---|
| 1402 | }
|
---|
| 1403 |
|
---|
| 1404 |
|
---|
| 1405 | /**
|
---|
| 1406 | * Send persist timer zero-window probes to keep a connection active
|
---|
| 1407 | * when a window update is lost.
|
---|
| 1408 | *
|
---|
| 1409 | * Called by tcp_slowtmr()
|
---|
| 1410 | *
|
---|
| 1411 | * @param pcb the tcp_pcb for which to send a zero-window probe packet
|
---|
| 1412 | */
|
---|
| 1413 | void
|
---|
| 1414 | tcp_zero_window_probe(struct tcp_pcb *pcb)
|
---|
| 1415 | {
|
---|
| 1416 | struct pbuf *p;
|
---|
| 1417 | struct tcp_hdr *tcphdr;
|
---|
| 1418 | struct tcp_seg *seg;
|
---|
| 1419 | u16_t len;
|
---|
| 1420 | u8_t is_fin;
|
---|
| 1421 |
|
---|
| 1422 | LWIP_DEBUGF(TCP_DEBUG,
|
---|
| 1423 | ("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
|
---|
| 1424 | U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
|
---|
| 1425 | ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
|
---|
| 1426 | ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
|
---|
| 1427 |
|
---|
| 1428 | LWIP_DEBUGF(TCP_DEBUG,
|
---|
| 1429 | ("tcp_zero_window_probe: tcp_ticks %"U32_F
|
---|
| 1430 | " pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
---|
| 1431 | tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
|
---|
| 1432 |
|
---|
| 1433 | seg = pcb->unacked;
|
---|
| 1434 |
|
---|
| 1435 | if(seg == NULL) {
|
---|
| 1436 | seg = pcb->unsent;
|
---|
| 1437 | }
|
---|
| 1438 | if(seg == NULL) {
|
---|
| 1439 | return;
|
---|
| 1440 | }
|
---|
| 1441 |
|
---|
| 1442 | is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
|
---|
| 1443 | /* we want to send one seqno: either FIN or data (no options) */
|
---|
| 1444 | len = is_fin ? 0 : 1;
|
---|
| 1445 |
|
---|
| 1446 | p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
|
---|
| 1447 | if(p == NULL) {
|
---|
| 1448 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
|
---|
| 1449 | return;
|
---|
| 1450 | }
|
---|
| 1451 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1452 |
|
---|
| 1453 | if (is_fin) {
|
---|
| 1454 | /* FIN segment, no data */
|
---|
| 1455 | TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
|
---|
| 1456 | } else {
|
---|
| 1457 | /* Data segment, copy in one byte from the head of the unacked queue */
|
---|
| 1458 | char *d = ((char *)p->payload + TCP_HLEN);
|
---|
| 1459 | /* Depending on whether the segment has already been sent (unacked) or not
|
---|
| 1460 | (unsent), seg->p->payload points to the IP header or TCP header.
|
---|
| 1461 | Ensure we copy the first TCP data byte: */
|
---|
| 1462 | pbuf_copy_partial(seg->p, d, 1, seg->p->tot_len - seg->len);
|
---|
| 1463 | }
|
---|
| 1464 |
|
---|
| 1465 | #if CHECKSUM_GEN_TCP
|
---|
| 1466 | tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
|
---|
| 1467 | IP_PROTO_TCP, p->tot_len);
|
---|
| 1468 | #endif
|
---|
| 1469 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1470 |
|
---|
| 1471 | /* Send output to IP */
|
---|
| 1472 | #if LWIP_NETIF_HWADDRHINT
|
---|
| 1473 | ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
|
---|
| 1474 | &(pcb->addr_hint));
|
---|
| 1475 | #else /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1476 | ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
|
---|
| 1477 | #endif /* LWIP_NETIF_HWADDRHINT*/
|
---|
| 1478 |
|
---|
| 1479 | pbuf_free(p);
|
---|
| 1480 |
|
---|
| 1481 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
|
---|
| 1482 | " ackno %"U32_F".\n",
|
---|
| 1483 | pcb->snd_nxt - 1, pcb->rcv_nxt));
|
---|
| 1484 | }
|
---|
| 1485 | #endif /* LWIP_TCP */
|
---|