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lwip/core/tcp_out.c@0:d7bd7384a37c, 2016-12-07 (annotated)

Committer:
grzemich
Date:
Wed Dec 07 23:47:50 2016 +0000
Revision:
0:d7bd7384a37c
dgd

Who changed what in which revision?

UserRevisionLine numberNew contents of line
grzemich 0:d7bd7384a37c 1 /**
grzemich 0:d7bd7384a37c 2 * @file
grzemich 0:d7bd7384a37c 3 * Transmission Control Protocol, outgoing traffic
grzemich 0:d7bd7384a37c 4 *
grzemich 0:d7bd7384a37c 5 * The output functions of TCP.
grzemich 0:d7bd7384a37c 6 *
grzemich 0:d7bd7384a37c 7 */
grzemich 0:d7bd7384a37c 8
grzemich 0:d7bd7384a37c 9 /*
grzemich 0:d7bd7384a37c 10 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
grzemich 0:d7bd7384a37c 11 * All rights reserved.
grzemich 0:d7bd7384a37c 12 *
grzemich 0:d7bd7384a37c 13 * Redistribution and use in source and binary forms, with or without modification,
grzemich 0:d7bd7384a37c 14 * are permitted provided that the following conditions are met:
grzemich 0:d7bd7384a37c 15 *
grzemich 0:d7bd7384a37c 16 * 1. Redistributions of source code must retain the above copyright notice,
grzemich 0:d7bd7384a37c 17 * this list of conditions and the following disclaimer.
grzemich 0:d7bd7384a37c 18 * 2. Redistributions in binary form must reproduce the above copyright notice,
grzemich 0:d7bd7384a37c 19 * this list of conditions and the following disclaimer in the documentation
grzemich 0:d7bd7384a37c 20 * and/or other materials provided with the distribution.
grzemich 0:d7bd7384a37c 21 * 3. The name of the author may not be used to endorse or promote products
grzemich 0:d7bd7384a37c 22 * derived from this software without specific prior written permission.
grzemich 0:d7bd7384a37c 23 *
grzemich 0:d7bd7384a37c 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
grzemich 0:d7bd7384a37c 25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
grzemich 0:d7bd7384a37c 26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
grzemich 0:d7bd7384a37c 27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
grzemich 0:d7bd7384a37c 28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
grzemich 0:d7bd7384a37c 29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
grzemich 0:d7bd7384a37c 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
grzemich 0:d7bd7384a37c 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
grzemich 0:d7bd7384a37c 32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
grzemich 0:d7bd7384a37c 33 * OF SUCH DAMAGE.
grzemich 0:d7bd7384a37c 34 *
grzemich 0:d7bd7384a37c 35 * This file is part of the lwIP TCP/IP stack.
grzemich 0:d7bd7384a37c 36 *
grzemich 0:d7bd7384a37c 37 * Author: Adam Dunkels <adam@sics.se>
grzemich 0:d7bd7384a37c 38 *
grzemich 0:d7bd7384a37c 39 */
grzemich 0:d7bd7384a37c 40
grzemich 0:d7bd7384a37c 41 #include "lwip/opt.h"
grzemich 0:d7bd7384a37c 42
grzemich 0:d7bd7384a37c 43 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
grzemich 0:d7bd7384a37c 44
grzemich 0:d7bd7384a37c 45 #include "lwip/tcp_impl.h"
grzemich 0:d7bd7384a37c 46 #include "lwip/def.h"
grzemich 0:d7bd7384a37c 47 #include "lwip/mem.h"
grzemich 0:d7bd7384a37c 48 #include "lwip/memp.h"
grzemich 0:d7bd7384a37c 49 #include "lwip/sys.h"
grzemich 0:d7bd7384a37c 50 #include "lwip/ip_addr.h"
grzemich 0:d7bd7384a37c 51 #include "lwip/netif.h"
grzemich 0:d7bd7384a37c 52 #include "lwip/inet_chksum.h"
grzemich 0:d7bd7384a37c 53 #include "lwip/stats.h"
grzemich 0:d7bd7384a37c 54 #include "lwip/snmp.h"
grzemich 0:d7bd7384a37c 55
grzemich 0:d7bd7384a37c 56 #include <string.h>
grzemich 0:d7bd7384a37c 57
grzemich 0:d7bd7384a37c 58 /* Define some copy-macros for checksum-on-copy so that the code looks
grzemich 0:d7bd7384a37c 59 nicer by preventing too many ifdef's. */
grzemich 0:d7bd7384a37c 60 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 61 #define TCP_DATA_COPY(dst, src, len, seg) do { \
grzemich 0:d7bd7384a37c 62 tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
grzemich 0:d7bd7384a37c 63 len, &seg->chksum, &seg->chksum_swapped); \
grzemich 0:d7bd7384a37c 64 seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
grzemich 0:d7bd7384a37c 65 #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
grzemich 0:d7bd7384a37c 66 tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
grzemich 0:d7bd7384a37c 67 #else /* TCP_CHECKSUM_ON_COPY*/
grzemich 0:d7bd7384a37c 68 #define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
grzemich 0:d7bd7384a37c 69 #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
grzemich 0:d7bd7384a37c 70 #endif /* TCP_CHECKSUM_ON_COPY*/
grzemich 0:d7bd7384a37c 71
grzemich 0:d7bd7384a37c 72 /** Define this to 1 for an extra check that the output checksum is valid
grzemich 0:d7bd7384a37c 73 * (usefule when the checksum is generated by the application, not the stack) */
grzemich 0:d7bd7384a37c 74 #ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
grzemich 0:d7bd7384a37c 75 #define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
grzemich 0:d7bd7384a37c 76 #endif
grzemich 0:d7bd7384a37c 77
grzemich 0:d7bd7384a37c 78 /* Forward declarations.*/
grzemich 0:d7bd7384a37c 79 static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb);
grzemich 0:d7bd7384a37c 80
grzemich 0:d7bd7384a37c 81 /** Allocate a pbuf and create a tcphdr at p->payload, used for output
grzemich 0:d7bd7384a37c 82 * functions other than the default tcp_output -> tcp_output_segment
grzemich 0:d7bd7384a37c 83 * (e.g. tcp_send_empty_ack, etc.)
grzemich 0:d7bd7384a37c 84 *
grzemich 0:d7bd7384a37c 85 * @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
grzemich 0:d7bd7384a37c 86 * @param optlen length of header-options
grzemich 0:d7bd7384a37c 87 * @param datalen length of tcp data to reserve in pbuf
grzemich 0:d7bd7384a37c 88 * @param seqno_be seqno in network byte order (big-endian)
grzemich 0:d7bd7384a37c 89 * @return pbuf with p->payload being the tcp_hdr
grzemich 0:d7bd7384a37c 90 */
grzemich 0:d7bd7384a37c 91 static struct pbuf *
grzemich 0:d7bd7384a37c 92 tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
grzemich 0:d7bd7384a37c 93 u32_t seqno_be /* already in network byte order */)
grzemich 0:d7bd7384a37c 94 {
grzemich 0:d7bd7384a37c 95 struct tcp_hdr *tcphdr;
grzemich 0:d7bd7384a37c 96 struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
grzemich 0:d7bd7384a37c 97 if (p != NULL) {
grzemich 0:d7bd7384a37c 98 LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
grzemich 0:d7bd7384a37c 99 (p->len >= TCP_HLEN + optlen));
grzemich 0:d7bd7384a37c 100 tcphdr = (struct tcp_hdr *)p->payload;
grzemich 0:d7bd7384a37c 101 tcphdr->src = htons(pcb->local_port);
grzemich 0:d7bd7384a37c 102 tcphdr->dest = htons(pcb->remote_port);
grzemich 0:d7bd7384a37c 103 tcphdr->seqno = seqno_be;
grzemich 0:d7bd7384a37c 104 tcphdr->ackno = htonl(pcb->rcv_nxt);
grzemich 0:d7bd7384a37c 105 TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
grzemich 0:d7bd7384a37c 106 tcphdr->wnd = htons(pcb->rcv_ann_wnd);
grzemich 0:d7bd7384a37c 107 tcphdr->chksum = 0;
grzemich 0:d7bd7384a37c 108 tcphdr->urgp = 0;
grzemich 0:d7bd7384a37c 109
grzemich 0:d7bd7384a37c 110 /* If we're sending a packet, update the announced right window edge */
grzemich 0:d7bd7384a37c 111 pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
grzemich 0:d7bd7384a37c 112 }
grzemich 0:d7bd7384a37c 113 return p;
grzemich 0:d7bd7384a37c 114 }
grzemich 0:d7bd7384a37c 115
grzemich 0:d7bd7384a37c 116 /**
grzemich 0:d7bd7384a37c 117 * Called by tcp_close() to send a segment including FIN flag but not data.
grzemich 0:d7bd7384a37c 118 *
grzemich 0:d7bd7384a37c 119 * @param pcb the tcp_pcb over which to send a segment
grzemich 0:d7bd7384a37c 120 * @return ERR_OK if sent, another err_t otherwise
grzemich 0:d7bd7384a37c 121 */
grzemich 0:d7bd7384a37c 122 err_t
grzemich 0:d7bd7384a37c 123 tcp_send_fin(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 124 {
grzemich 0:d7bd7384a37c 125 /* first, try to add the fin to the last unsent segment */
grzemich 0:d7bd7384a37c 126 if (pcb->unsent != NULL) {
grzemich 0:d7bd7384a37c 127 struct tcp_seg *last_unsent;
grzemich 0:d7bd7384a37c 128 for (last_unsent = pcb->unsent; last_unsent->next != NULL;
grzemich 0:d7bd7384a37c 129 last_unsent = last_unsent->next);
grzemich 0:d7bd7384a37c 130
grzemich 0:d7bd7384a37c 131 if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
grzemich 0:d7bd7384a37c 132 /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
grzemich 0:d7bd7384a37c 133 TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
grzemich 0:d7bd7384a37c 134 return ERR_OK;
grzemich 0:d7bd7384a37c 135 }
grzemich 0:d7bd7384a37c 136 }
grzemich 0:d7bd7384a37c 137 /* no data, no length, flags, copy=1, no optdata */
grzemich 0:d7bd7384a37c 138 return tcp_enqueue_flags(pcb, TCP_FIN);
grzemich 0:d7bd7384a37c 139 }
grzemich 0:d7bd7384a37c 140
grzemich 0:d7bd7384a37c 141 /**
grzemich 0:d7bd7384a37c 142 * Create a TCP segment with prefilled header.
grzemich 0:d7bd7384a37c 143 *
grzemich 0:d7bd7384a37c 144 * Called by tcp_write and tcp_enqueue_flags.
grzemich 0:d7bd7384a37c 145 *
grzemich 0:d7bd7384a37c 146 * @param pcb Protocol control block for the TCP connection.
grzemich 0:d7bd7384a37c 147 * @param p pbuf that is used to hold the TCP header.
grzemich 0:d7bd7384a37c 148 * @param flags TCP flags for header.
grzemich 0:d7bd7384a37c 149 * @param seqno TCP sequence number of this packet
grzemich 0:d7bd7384a37c 150 * @param optflags options to include in TCP header
grzemich 0:d7bd7384a37c 151 * @return a new tcp_seg pointing to p, or NULL.
grzemich 0:d7bd7384a37c 152 * The TCP header is filled in except ackno and wnd.
grzemich 0:d7bd7384a37c 153 * p is freed on failure.
grzemich 0:d7bd7384a37c 154 */
grzemich 0:d7bd7384a37c 155 static struct tcp_seg *
grzemich 0:d7bd7384a37c 156 tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
grzemich 0:d7bd7384a37c 157 {
grzemich 0:d7bd7384a37c 158 struct tcp_seg *seg;
grzemich 0:d7bd7384a37c 159 u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
grzemich 0:d7bd7384a37c 160
grzemich 0:d7bd7384a37c 161 if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
grzemich 0:d7bd7384a37c 162 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
grzemich 0:d7bd7384a37c 163 pbuf_free(p);
grzemich 0:d7bd7384a37c 164 return NULL;
grzemich 0:d7bd7384a37c 165 }
grzemich 0:d7bd7384a37c 166 seg->flags = optflags;
grzemich 0:d7bd7384a37c 167 seg->next = NULL;
grzemich 0:d7bd7384a37c 168 seg->p = p;
grzemich 0:d7bd7384a37c 169 seg->len = p->tot_len - optlen;
grzemich 0:d7bd7384a37c 170 #if TCP_OVERSIZE_DBGCHECK
grzemich 0:d7bd7384a37c 171 seg->oversize_left = 0;
grzemich 0:d7bd7384a37c 172 #endif /* TCP_OVERSIZE_DBGCHECK */
grzemich 0:d7bd7384a37c 173 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 174 seg->chksum = 0;
grzemich 0:d7bd7384a37c 175 seg->chksum_swapped = 0;
grzemich 0:d7bd7384a37c 176 /* check optflags */
grzemich 0:d7bd7384a37c 177 LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
grzemich 0:d7bd7384a37c 178 (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
grzemich 0:d7bd7384a37c 179 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 180
grzemich 0:d7bd7384a37c 181 /* build TCP header */
grzemich 0:d7bd7384a37c 182 if (pbuf_header(p, TCP_HLEN)) {
grzemich 0:d7bd7384a37c 183 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
grzemich 0:d7bd7384a37c 184 TCP_STATS_INC(tcp.err);
grzemich 0:d7bd7384a37c 185 tcp_seg_free(seg);
grzemich 0:d7bd7384a37c 186 return NULL;
grzemich 0:d7bd7384a37c 187 }
grzemich 0:d7bd7384a37c 188 seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
grzemich 0:d7bd7384a37c 189 seg->tcphdr->src = htons(pcb->local_port);
grzemich 0:d7bd7384a37c 190 seg->tcphdr->dest = htons(pcb->remote_port);
grzemich 0:d7bd7384a37c 191 seg->tcphdr->seqno = htonl(seqno);
grzemich 0:d7bd7384a37c 192 /* ackno is set in tcp_output */
grzemich 0:d7bd7384a37c 193 TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
grzemich 0:d7bd7384a37c 194 /* wnd and chksum are set in tcp_output */
grzemich 0:d7bd7384a37c 195 seg->tcphdr->urgp = 0;
grzemich 0:d7bd7384a37c 196 return seg;
grzemich 0:d7bd7384a37c 197 }
grzemich 0:d7bd7384a37c 198
grzemich 0:d7bd7384a37c 199 /**
grzemich 0:d7bd7384a37c 200 * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
grzemich 0:d7bd7384a37c 201 *
grzemich 0:d7bd7384a37c 202 * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
grzemich 0:d7bd7384a37c 203 * there may be extra bytes available at the end.
grzemich 0:d7bd7384a37c 204 *
grzemich 0:d7bd7384a37c 205 * @param layer flag to define header size.
grzemich 0:d7bd7384a37c 206 * @param length size of the pbuf's payload.
grzemich 0:d7bd7384a37c 207 * @param max_length maximum usable size of payload+oversize.
grzemich 0:d7bd7384a37c 208 * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
grzemich 0:d7bd7384a37c 209 * @param pcb The TCP connection that willo enqueue the pbuf.
grzemich 0:d7bd7384a37c 210 * @param apiflags API flags given to tcp_write.
grzemich 0:d7bd7384a37c 211 * @param first_seg true when this pbuf will be used in the first enqueued segment.
grzemich 0:d7bd7384a37c 212 * @param
grzemich 0:d7bd7384a37c 213 */
grzemich 0:d7bd7384a37c 214 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 215 static struct pbuf *
grzemich 0:d7bd7384a37c 216 tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
grzemich 0:d7bd7384a37c 217 u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
grzemich 0:d7bd7384a37c 218 u8_t first_seg)
grzemich 0:d7bd7384a37c 219 {
grzemich 0:d7bd7384a37c 220 struct pbuf *p;
grzemich 0:d7bd7384a37c 221 u16_t alloc = length;
grzemich 0:d7bd7384a37c 222
grzemich 0:d7bd7384a37c 223 #if LWIP_NETIF_TX_SINGLE_PBUF
grzemich 0:d7bd7384a37c 224 LWIP_UNUSED_ARG(max_length);
grzemich 0:d7bd7384a37c 225 LWIP_UNUSED_ARG(pcb);
grzemich 0:d7bd7384a37c 226 LWIP_UNUSED_ARG(apiflags);
grzemich 0:d7bd7384a37c 227 LWIP_UNUSED_ARG(first_seg);
grzemich 0:d7bd7384a37c 228 /* always create MSS-sized pbufs */
grzemich 0:d7bd7384a37c 229 alloc = TCP_MSS;
grzemich 0:d7bd7384a37c 230 #else /* LWIP_NETIF_TX_SINGLE_PBUF */
grzemich 0:d7bd7384a37c 231 if (length < max_length) {
grzemich 0:d7bd7384a37c 232 /* Should we allocate an oversized pbuf, or just the minimum
grzemich 0:d7bd7384a37c 233 * length required? If tcp_write is going to be called again
grzemich 0:d7bd7384a37c 234 * before this segment is transmitted, we want the oversized
grzemich 0:d7bd7384a37c 235 * buffer. If the segment will be transmitted immediately, we can
grzemich 0:d7bd7384a37c 236 * save memory by allocating only length. We use a simple
grzemich 0:d7bd7384a37c 237 * heuristic based on the following information:
grzemich 0:d7bd7384a37c 238 *
grzemich 0:d7bd7384a37c 239 * Did the user set TCP_WRITE_FLAG_MORE?
grzemich 0:d7bd7384a37c 240 *
grzemich 0:d7bd7384a37c 241 * Will the Nagle algorithm defer transmission of this segment?
grzemich 0:d7bd7384a37c 242 */
grzemich 0:d7bd7384a37c 243 if ((apiflags & TCP_WRITE_FLAG_MORE) ||
grzemich 0:d7bd7384a37c 244 (!(pcb->flags & TF_NODELAY) &&
grzemich 0:d7bd7384a37c 245 (!first_seg ||
grzemich 0:d7bd7384a37c 246 pcb->unsent != NULL ||
grzemich 0:d7bd7384a37c 247 pcb->unacked != NULL))) {
grzemich 0:d7bd7384a37c 248 alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
grzemich 0:d7bd7384a37c 249 }
grzemich 0:d7bd7384a37c 250 }
grzemich 0:d7bd7384a37c 251 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
grzemich 0:d7bd7384a37c 252 p = pbuf_alloc(layer, alloc, PBUF_RAM);
grzemich 0:d7bd7384a37c 253 if (p == NULL) {
grzemich 0:d7bd7384a37c 254 return NULL;
grzemich 0:d7bd7384a37c 255 }
grzemich 0:d7bd7384a37c 256 LWIP_ASSERT("need unchained pbuf", p->next == NULL);
grzemich 0:d7bd7384a37c 257 *oversize = p->len - length;
grzemich 0:d7bd7384a37c 258 /* trim p->len to the currently used size */
grzemich 0:d7bd7384a37c 259 p->len = p->tot_len = length;
grzemich 0:d7bd7384a37c 260 return p;
grzemich 0:d7bd7384a37c 261 }
grzemich 0:d7bd7384a37c 262 #else /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 263 #define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
grzemich 0:d7bd7384a37c 264 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 265
grzemich 0:d7bd7384a37c 266 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 267 /** Add a checksum of newly added data to the segment */
grzemich 0:d7bd7384a37c 268 static void
grzemich 0:d7bd7384a37c 269 tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
grzemich 0:d7bd7384a37c 270 u8_t *seg_chksum_swapped)
grzemich 0:d7bd7384a37c 271 {
grzemich 0:d7bd7384a37c 272 u32_t helper;
grzemich 0:d7bd7384a37c 273 /* add chksum to old chksum and fold to u16_t */
grzemich 0:d7bd7384a37c 274 helper = chksum + *seg_chksum;
grzemich 0:d7bd7384a37c 275 chksum = FOLD_U32T(helper);
grzemich 0:d7bd7384a37c 276 if ((len & 1) != 0) {
grzemich 0:d7bd7384a37c 277 *seg_chksum_swapped = 1 - *seg_chksum_swapped;
grzemich 0:d7bd7384a37c 278 chksum = SWAP_BYTES_IN_WORD(chksum);
grzemich 0:d7bd7384a37c 279 }
grzemich 0:d7bd7384a37c 280 *seg_chksum = chksum;
grzemich 0:d7bd7384a37c 281 }
grzemich 0:d7bd7384a37c 282 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 283
grzemich 0:d7bd7384a37c 284 /** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
grzemich 0:d7bd7384a37c 285 *
grzemich 0:d7bd7384a37c 286 * @param pcb the tcp pcb to check for
grzemich 0:d7bd7384a37c 287 * @param len length of data to send (checked agains snd_buf)
grzemich 0:d7bd7384a37c 288 * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
grzemich 0:d7bd7384a37c 289 */
grzemich 0:d7bd7384a37c 290 static err_t
grzemich 0:d7bd7384a37c 291 tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
grzemich 0:d7bd7384a37c 292 {
grzemich 0:d7bd7384a37c 293 /* connection is in invalid state for data transmission? */
grzemich 0:d7bd7384a37c 294 if ((pcb->state != ESTABLISHED) &&
grzemich 0:d7bd7384a37c 295 (pcb->state != CLOSE_WAIT) &&
grzemich 0:d7bd7384a37c 296 (pcb->state != SYN_SENT) &&
grzemich 0:d7bd7384a37c 297 (pcb->state != SYN_RCVD)) {
grzemich 0:d7bd7384a37c 298 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
grzemich 0:d7bd7384a37c 299 return ERR_CONN;
grzemich 0:d7bd7384a37c 300 } else if (len == 0) {
grzemich 0:d7bd7384a37c 301 return ERR_OK;
grzemich 0:d7bd7384a37c 302 }
grzemich 0:d7bd7384a37c 303
grzemich 0:d7bd7384a37c 304 /* fail on too much data */
grzemich 0:d7bd7384a37c 305 if (len > pcb->snd_buf) {
grzemich 0:d7bd7384a37c 306 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
grzemich 0:d7bd7384a37c 307 len, pcb->snd_buf));
grzemich 0:d7bd7384a37c 308 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 309 return ERR_MEM;
grzemich 0:d7bd7384a37c 310 }
grzemich 0:d7bd7384a37c 311
grzemich 0:d7bd7384a37c 312 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
grzemich 0:d7bd7384a37c 313
grzemich 0:d7bd7384a37c 314 /* If total number of pbufs on the unsent/unacked queues exceeds the
grzemich 0:d7bd7384a37c 315 * configured maximum, return an error */
grzemich 0:d7bd7384a37c 316 /* check for configured max queuelen and possible overflow */
grzemich 0:d7bd7384a37c 317 if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
grzemich 0:d7bd7384a37c 318 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
grzemich 0:d7bd7384a37c 319 pcb->snd_queuelen, TCP_SND_QUEUELEN));
grzemich 0:d7bd7384a37c 320 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 321 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 322 return ERR_MEM;
grzemich 0:d7bd7384a37c 323 }
grzemich 0:d7bd7384a37c 324 if (pcb->snd_queuelen != 0) {
grzemich 0:d7bd7384a37c 325 LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
grzemich 0:d7bd7384a37c 326 pcb->unacked != NULL || pcb->unsent != NULL);
grzemich 0:d7bd7384a37c 327 } else {
grzemich 0:d7bd7384a37c 328 LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
grzemich 0:d7bd7384a37c 329 pcb->unacked == NULL && pcb->unsent == NULL);
grzemich 0:d7bd7384a37c 330 }
grzemich 0:d7bd7384a37c 331 return ERR_OK;
grzemich 0:d7bd7384a37c 332 }
grzemich 0:d7bd7384a37c 333
grzemich 0:d7bd7384a37c 334 /**
grzemich 0:d7bd7384a37c 335 * Write data for sending (but does not send it immediately).
grzemich 0:d7bd7384a37c 336 *
grzemich 0:d7bd7384a37c 337 * It waits in the expectation of more data being sent soon (as
grzemich 0:d7bd7384a37c 338 * it can send them more efficiently by combining them together).
grzemich 0:d7bd7384a37c 339 * To prompt the system to send data now, call tcp_output() after
grzemich 0:d7bd7384a37c 340 * calling tcp_write().
grzemich 0:d7bd7384a37c 341 *
grzemich 0:d7bd7384a37c 342 * @param pcb Protocol control block for the TCP connection to enqueue data for.
grzemich 0:d7bd7384a37c 343 * @param arg Pointer to the data to be enqueued for sending.
grzemich 0:d7bd7384a37c 344 * @param len Data length in bytes
grzemich 0:d7bd7384a37c 345 * @param apiflags combination of following flags :
grzemich 0:d7bd7384a37c 346 * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
grzemich 0:d7bd7384a37c 347 * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
grzemich 0:d7bd7384a37c 348 * @return ERR_OK if enqueued, another err_t on error
grzemich 0:d7bd7384a37c 349 */
grzemich 0:d7bd7384a37c 350 err_t
grzemich 0:d7bd7384a37c 351 tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
grzemich 0:d7bd7384a37c 352 {
grzemich 0:d7bd7384a37c 353 struct pbuf *concat_p = NULL;
grzemich 0:d7bd7384a37c 354 struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
grzemich 0:d7bd7384a37c 355 u16_t pos = 0; /* position in 'arg' data */
grzemich 0:d7bd7384a37c 356 u16_t queuelen;
grzemich 0:d7bd7384a37c 357 u8_t optlen = 0;
grzemich 0:d7bd7384a37c 358 u8_t optflags = 0;
grzemich 0:d7bd7384a37c 359 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 360 u16_t oversize = 0;
grzemich 0:d7bd7384a37c 361 u16_t oversize_used = 0;
grzemich 0:d7bd7384a37c 362 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 363 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 364 u16_t concat_chksum = 0;
grzemich 0:d7bd7384a37c 365 u8_t concat_chksum_swapped = 0;
grzemich 0:d7bd7384a37c 366 u16_t concat_chksummed = 0;
grzemich 0:d7bd7384a37c 367 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 368 err_t err;
grzemich 0:d7bd7384a37c 369
grzemich 0:d7bd7384a37c 370 #if LWIP_NETIF_TX_SINGLE_PBUF
grzemich 0:d7bd7384a37c 371 /* Always copy to try to create single pbufs for TX */
grzemich 0:d7bd7384a37c 372 apiflags |= TCP_WRITE_FLAG_COPY;
grzemich 0:d7bd7384a37c 373 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
grzemich 0:d7bd7384a37c 374
grzemich 0:d7bd7384a37c 375 LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
grzemich 0:d7bd7384a37c 376 (void *)pcb, arg, len, (u16_t)apiflags));
grzemich 0:d7bd7384a37c 377 LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
grzemich 0:d7bd7384a37c 378 arg != NULL, return ERR_ARG;);
grzemich 0:d7bd7384a37c 379
grzemich 0:d7bd7384a37c 380 err = tcp_write_checks(pcb, len);
grzemich 0:d7bd7384a37c 381 if (err != ERR_OK) {
grzemich 0:d7bd7384a37c 382 return err;
grzemich 0:d7bd7384a37c 383 }
grzemich 0:d7bd7384a37c 384 queuelen = pcb->snd_queuelen;
grzemich 0:d7bd7384a37c 385
grzemich 0:d7bd7384a37c 386 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 387 if ((pcb->flags & TF_TIMESTAMP)) {
grzemich 0:d7bd7384a37c 388 optflags = TF_SEG_OPTS_TS;
grzemich 0:d7bd7384a37c 389 optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
grzemich 0:d7bd7384a37c 390 }
grzemich 0:d7bd7384a37c 391 #endif /* LWIP_TCP_TIMESTAMPS */
grzemich 0:d7bd7384a37c 392
grzemich 0:d7bd7384a37c 393
grzemich 0:d7bd7384a37c 394 /*
grzemich 0:d7bd7384a37c 395 * TCP segmentation is done in three phases with increasing complexity:
grzemich 0:d7bd7384a37c 396 *
grzemich 0:d7bd7384a37c 397 * 1. Copy data directly into an oversized pbuf.
grzemich 0:d7bd7384a37c 398 * 2. Chain a new pbuf to the end of pcb->unsent.
grzemich 0:d7bd7384a37c 399 * 3. Create new segments.
grzemich 0:d7bd7384a37c 400 *
grzemich 0:d7bd7384a37c 401 * We may run out of memory at any point. In that case we must
grzemich 0:d7bd7384a37c 402 * return ERR_MEM and not change anything in pcb. Therefore, all
grzemich 0:d7bd7384a37c 403 * changes are recorded in local variables and committed at the end
grzemich 0:d7bd7384a37c 404 * of the function. Some pcb fields are maintained in local copies:
grzemich 0:d7bd7384a37c 405 *
grzemich 0:d7bd7384a37c 406 * queuelen = pcb->snd_queuelen
grzemich 0:d7bd7384a37c 407 * oversize = pcb->unsent_oversize
grzemich 0:d7bd7384a37c 408 *
grzemich 0:d7bd7384a37c 409 * These variables are set consistently by the phases:
grzemich 0:d7bd7384a37c 410 *
grzemich 0:d7bd7384a37c 411 * seg points to the last segment tampered with.
grzemich 0:d7bd7384a37c 412 *
grzemich 0:d7bd7384a37c 413 * pos records progress as data is segmented.
grzemich 0:d7bd7384a37c 414 */
grzemich 0:d7bd7384a37c 415
grzemich 0:d7bd7384a37c 416 /* Find the tail of the unsent queue. */
grzemich 0:d7bd7384a37c 417 if (pcb->unsent != NULL) {
grzemich 0:d7bd7384a37c 418 u16_t space;
grzemich 0:d7bd7384a37c 419 u16_t unsent_optlen;
grzemich 0:d7bd7384a37c 420
grzemich 0:d7bd7384a37c 421 /* @todo: this could be sped up by keeping last_unsent in the pcb */
grzemich 0:d7bd7384a37c 422 for (last_unsent = pcb->unsent; last_unsent->next != NULL;
grzemich 0:d7bd7384a37c 423 last_unsent = last_unsent->next);
grzemich 0:d7bd7384a37c 424
grzemich 0:d7bd7384a37c 425 /* Usable space at the end of the last unsent segment */
grzemich 0:d7bd7384a37c 426 unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
grzemich 0:d7bd7384a37c 427 space = pcb->mss - (last_unsent->len + unsent_optlen);
grzemich 0:d7bd7384a37c 428
grzemich 0:d7bd7384a37c 429 /*
grzemich 0:d7bd7384a37c 430 * Phase 1: Copy data directly into an oversized pbuf.
grzemich 0:d7bd7384a37c 431 *
grzemich 0:d7bd7384a37c 432 * The number of bytes copied is recorded in the oversize_used
grzemich 0:d7bd7384a37c 433 * variable. The actual copying is done at the bottom of the
grzemich 0:d7bd7384a37c 434 * function.
grzemich 0:d7bd7384a37c 435 */
grzemich 0:d7bd7384a37c 436 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 437 #if TCP_OVERSIZE_DBGCHECK
grzemich 0:d7bd7384a37c 438 /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
grzemich 0:d7bd7384a37c 439 LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
grzemich 0:d7bd7384a37c 440 pcb->unsent_oversize == last_unsent->oversize_left);
grzemich 0:d7bd7384a37c 441 #endif /* TCP_OVERSIZE_DBGCHECK */
grzemich 0:d7bd7384a37c 442 oversize = pcb->unsent_oversize;
grzemich 0:d7bd7384a37c 443 if (oversize > 0) {
grzemich 0:d7bd7384a37c 444 LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
grzemich 0:d7bd7384a37c 445 seg = last_unsent;
grzemich 0:d7bd7384a37c 446 oversize_used = oversize < len ? oversize : len;
grzemich 0:d7bd7384a37c 447 pos += oversize_used;
grzemich 0:d7bd7384a37c 448 oversize -= oversize_used;
grzemich 0:d7bd7384a37c 449 space -= oversize_used;
grzemich 0:d7bd7384a37c 450 }
grzemich 0:d7bd7384a37c 451 /* now we are either finished or oversize is zero */
grzemich 0:d7bd7384a37c 452 LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
grzemich 0:d7bd7384a37c 453 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 454
grzemich 0:d7bd7384a37c 455 /*
grzemich 0:d7bd7384a37c 456 * Phase 2: Chain a new pbuf to the end of pcb->unsent.
grzemich 0:d7bd7384a37c 457 *
grzemich 0:d7bd7384a37c 458 * We don't extend segments containing SYN/FIN flags or options
grzemich 0:d7bd7384a37c 459 * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
grzemich 0:d7bd7384a37c 460 * the end.
grzemich 0:d7bd7384a37c 461 */
grzemich 0:d7bd7384a37c 462 if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
grzemich 0:d7bd7384a37c 463 u16_t seglen = space < len - pos ? space : len - pos;
grzemich 0:d7bd7384a37c 464 seg = last_unsent;
grzemich 0:d7bd7384a37c 465
grzemich 0:d7bd7384a37c 466 /* Create a pbuf with a copy or reference to seglen bytes. We
grzemich 0:d7bd7384a37c 467 * can use PBUF_RAW here since the data appears in the middle of
grzemich 0:d7bd7384a37c 468 * a segment. A header will never be prepended. */
grzemich 0:d7bd7384a37c 469 if (apiflags & TCP_WRITE_FLAG_COPY) {
grzemich 0:d7bd7384a37c 470 /* Data is copied */
grzemich 0:d7bd7384a37c 471 if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
grzemich 0:d7bd7384a37c 472 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
grzemich 0:d7bd7384a37c 473 ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
grzemich 0:d7bd7384a37c 474 seglen));
grzemich 0:d7bd7384a37c 475 goto memerr;
grzemich 0:d7bd7384a37c 476 }
grzemich 0:d7bd7384a37c 477 #if TCP_OVERSIZE_DBGCHECK
grzemich 0:d7bd7384a37c 478 last_unsent->oversize_left = oversize;
grzemich 0:d7bd7384a37c 479 #endif /* TCP_OVERSIZE_DBGCHECK */
grzemich 0:d7bd7384a37c 480 TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
grzemich 0:d7bd7384a37c 481 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 482 concat_chksummed += seglen;
grzemich 0:d7bd7384a37c 483 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 484 } else {
grzemich 0:d7bd7384a37c 485 /* Data is not copied */
grzemich 0:d7bd7384a37c 486 if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
grzemich 0:d7bd7384a37c 487 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
grzemich 0:d7bd7384a37c 488 ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
grzemich 0:d7bd7384a37c 489 goto memerr;
grzemich 0:d7bd7384a37c 490 }
grzemich 0:d7bd7384a37c 491 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 492 /* calculate the checksum of nocopy-data */
grzemich 0:d7bd7384a37c 493 tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
grzemich 0:d7bd7384a37c 494 &concat_chksum, &concat_chksum_swapped);
grzemich 0:d7bd7384a37c 495 concat_chksummed += seglen;
grzemich 0:d7bd7384a37c 496 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 497 /* reference the non-volatile payload data */
grzemich 0:d7bd7384a37c 498 concat_p->payload = (u8_t*)arg + pos;
grzemich 0:d7bd7384a37c 499 }
grzemich 0:d7bd7384a37c 500
grzemich 0:d7bd7384a37c 501 pos += seglen;
grzemich 0:d7bd7384a37c 502 queuelen += pbuf_clen(concat_p);
grzemich 0:d7bd7384a37c 503 }
grzemich 0:d7bd7384a37c 504 } else {
grzemich 0:d7bd7384a37c 505 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 506 LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
grzemich 0:d7bd7384a37c 507 pcb->unsent_oversize == 0);
grzemich 0:d7bd7384a37c 508 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 509 }
grzemich 0:d7bd7384a37c 510
grzemich 0:d7bd7384a37c 511 /*
grzemich 0:d7bd7384a37c 512 * Phase 3: Create new segments.
grzemich 0:d7bd7384a37c 513 *
grzemich 0:d7bd7384a37c 514 * The new segments are chained together in the local 'queue'
grzemich 0:d7bd7384a37c 515 * variable, ready to be appended to pcb->unsent.
grzemich 0:d7bd7384a37c 516 */
grzemich 0:d7bd7384a37c 517 while (pos < len) {
grzemich 0:d7bd7384a37c 518 struct pbuf *p;
grzemich 0:d7bd7384a37c 519 u16_t left = len - pos;
grzemich 0:d7bd7384a37c 520 u16_t max_len = pcb->mss - optlen;
grzemich 0:d7bd7384a37c 521 u16_t seglen = left > max_len ? max_len : left;
grzemich 0:d7bd7384a37c 522 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 523 u16_t chksum = 0;
grzemich 0:d7bd7384a37c 524 u8_t chksum_swapped = 0;
grzemich 0:d7bd7384a37c 525 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 526
grzemich 0:d7bd7384a37c 527 if (apiflags & TCP_WRITE_FLAG_COPY) {
grzemich 0:d7bd7384a37c 528 /* If copy is set, memory should be allocated and data copied
grzemich 0:d7bd7384a37c 529 * into pbuf */
grzemich 0:d7bd7384a37c 530 if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
grzemich 0:d7bd7384a37c 531 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
grzemich 0:d7bd7384a37c 532 goto memerr;
grzemich 0:d7bd7384a37c 533 }
grzemich 0:d7bd7384a37c 534 LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
grzemich 0:d7bd7384a37c 535 (p->len >= seglen));
grzemich 0:d7bd7384a37c 536 TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
grzemich 0:d7bd7384a37c 537 } else {
grzemich 0:d7bd7384a37c 538 /* Copy is not set: First allocate a pbuf for holding the data.
grzemich 0:d7bd7384a37c 539 * Since the referenced data is available at least until it is
grzemich 0:d7bd7384a37c 540 * sent out on the link (as it has to be ACKed by the remote
grzemich 0:d7bd7384a37c 541 * party) we can safely use PBUF_ROM instead of PBUF_REF here.
grzemich 0:d7bd7384a37c 542 */
grzemich 0:d7bd7384a37c 543 struct pbuf *p2;
grzemich 0:d7bd7384a37c 544 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 545 LWIP_ASSERT("oversize == 0", oversize == 0);
grzemich 0:d7bd7384a37c 546 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 547 if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
grzemich 0:d7bd7384a37c 548 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
grzemich 0:d7bd7384a37c 549 goto memerr;
grzemich 0:d7bd7384a37c 550 }
grzemich 0:d7bd7384a37c 551 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 552 /* calculate the checksum of nocopy-data */
grzemich 0:d7bd7384a37c 553 chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
grzemich 0:d7bd7384a37c 554 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 555 /* reference the non-volatile payload data */
grzemich 0:d7bd7384a37c 556 p2->payload = (u8_t*)arg + pos;
grzemich 0:d7bd7384a37c 557
grzemich 0:d7bd7384a37c 558 /* Second, allocate a pbuf for the headers. */
grzemich 0:d7bd7384a37c 559 if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
grzemich 0:d7bd7384a37c 560 /* If allocation fails, we have to deallocate the data pbuf as
grzemich 0:d7bd7384a37c 561 * well. */
grzemich 0:d7bd7384a37c 562 pbuf_free(p2);
grzemich 0:d7bd7384a37c 563 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for header pbuf\n"));
grzemich 0:d7bd7384a37c 564 goto memerr;
grzemich 0:d7bd7384a37c 565 }
grzemich 0:d7bd7384a37c 566 /* Concatenate the headers and data pbufs together. */
grzemich 0:d7bd7384a37c 567 pbuf_cat(p/*header*/, p2/*data*/);
grzemich 0:d7bd7384a37c 568 }
grzemich 0:d7bd7384a37c 569
grzemich 0:d7bd7384a37c 570 queuelen += pbuf_clen(p);
grzemich 0:d7bd7384a37c 571
grzemich 0:d7bd7384a37c 572 /* Now that there are more segments queued, we check again if the
grzemich 0:d7bd7384a37c 573 * length of the queue exceeds the configured maximum or
grzemich 0:d7bd7384a37c 574 * overflows. */
grzemich 0:d7bd7384a37c 575 if ((queuelen > TCP_SND_QUEUELEN) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
grzemich 0:d7bd7384a37c 576 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
grzemich 0:d7bd7384a37c 577 pbuf_free(p);
grzemich 0:d7bd7384a37c 578 goto memerr;
grzemich 0:d7bd7384a37c 579 }
grzemich 0:d7bd7384a37c 580
grzemich 0:d7bd7384a37c 581 if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
grzemich 0:d7bd7384a37c 582 goto memerr;
grzemich 0:d7bd7384a37c 583 }
grzemich 0:d7bd7384a37c 584 #if TCP_OVERSIZE_DBGCHECK
grzemich 0:d7bd7384a37c 585 seg->oversize_left = oversize;
grzemich 0:d7bd7384a37c 586 #endif /* TCP_OVERSIZE_DBGCHECK */
grzemich 0:d7bd7384a37c 587 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 588 seg->chksum = chksum;
grzemich 0:d7bd7384a37c 589 seg->chksum_swapped = chksum_swapped;
grzemich 0:d7bd7384a37c 590 seg->flags |= TF_SEG_DATA_CHECKSUMMED;
grzemich 0:d7bd7384a37c 591 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 592
grzemich 0:d7bd7384a37c 593 /* first segment of to-be-queued data? */
grzemich 0:d7bd7384a37c 594 if (queue == NULL) {
grzemich 0:d7bd7384a37c 595 queue = seg;
grzemich 0:d7bd7384a37c 596 } else {
grzemich 0:d7bd7384a37c 597 /* Attach the segment to the end of the queued segments */
grzemich 0:d7bd7384a37c 598 LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
grzemich 0:d7bd7384a37c 599 prev_seg->next = seg;
grzemich 0:d7bd7384a37c 600 }
grzemich 0:d7bd7384a37c 601 /* remember last segment of to-be-queued data for next iteration */
grzemich 0:d7bd7384a37c 602 prev_seg = seg;
grzemich 0:d7bd7384a37c 603
grzemich 0:d7bd7384a37c 604 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
grzemich 0:d7bd7384a37c 605 ntohl(seg->tcphdr->seqno),
grzemich 0:d7bd7384a37c 606 ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
grzemich 0:d7bd7384a37c 607
grzemich 0:d7bd7384a37c 608 pos += seglen;
grzemich 0:d7bd7384a37c 609 }
grzemich 0:d7bd7384a37c 610
grzemich 0:d7bd7384a37c 611 /*
grzemich 0:d7bd7384a37c 612 * All three segmentation phases were successful. We can commit the
grzemich 0:d7bd7384a37c 613 * transaction.
grzemich 0:d7bd7384a37c 614 */
grzemich 0:d7bd7384a37c 615
grzemich 0:d7bd7384a37c 616 /*
grzemich 0:d7bd7384a37c 617 * Phase 1: If data has been added to the preallocated tail of
grzemich 0:d7bd7384a37c 618 * last_unsent, we update the length fields of the pbuf chain.
grzemich 0:d7bd7384a37c 619 */
grzemich 0:d7bd7384a37c 620 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 621 if (oversize_used > 0) {
grzemich 0:d7bd7384a37c 622 struct pbuf *p;
grzemich 0:d7bd7384a37c 623 /* Bump tot_len of whole chain, len of tail */
grzemich 0:d7bd7384a37c 624 for (p = last_unsent->p; p; p = p->next) {
grzemich 0:d7bd7384a37c 625 p->tot_len += oversize_used;
grzemich 0:d7bd7384a37c 626 if (p->next == NULL) {
grzemich 0:d7bd7384a37c 627 TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
grzemich 0:d7bd7384a37c 628 p->len += oversize_used;
grzemich 0:d7bd7384a37c 629 }
grzemich 0:d7bd7384a37c 630 }
grzemich 0:d7bd7384a37c 631 last_unsent->len += oversize_used;
grzemich 0:d7bd7384a37c 632 #if TCP_OVERSIZE_DBGCHECK
grzemich 0:d7bd7384a37c 633 last_unsent->oversize_left -= oversize_used;
grzemich 0:d7bd7384a37c 634 #endif /* TCP_OVERSIZE_DBGCHECK */
grzemich 0:d7bd7384a37c 635 }
grzemich 0:d7bd7384a37c 636 pcb->unsent_oversize = oversize;
grzemich 0:d7bd7384a37c 637 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 638
grzemich 0:d7bd7384a37c 639 /*
grzemich 0:d7bd7384a37c 640 * Phase 2: concat_p can be concatenated onto last_unsent->p
grzemich 0:d7bd7384a37c 641 */
grzemich 0:d7bd7384a37c 642 if (concat_p != NULL) {
grzemich 0:d7bd7384a37c 643 LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
grzemich 0:d7bd7384a37c 644 (last_unsent != NULL));
grzemich 0:d7bd7384a37c 645 pbuf_cat(last_unsent->p, concat_p);
grzemich 0:d7bd7384a37c 646 last_unsent->len += concat_p->tot_len;
grzemich 0:d7bd7384a37c 647 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 648 if (concat_chksummed) {
grzemich 0:d7bd7384a37c 649 if (concat_chksum_swapped) {
grzemich 0:d7bd7384a37c 650 concat_chksum = SWAP_BYTES_IN_WORD(concat_chksum);
grzemich 0:d7bd7384a37c 651 }
grzemich 0:d7bd7384a37c 652 tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
grzemich 0:d7bd7384a37c 653 &last_unsent->chksum_swapped);
grzemich 0:d7bd7384a37c 654 last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
grzemich 0:d7bd7384a37c 655 }
grzemich 0:d7bd7384a37c 656 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 657 }
grzemich 0:d7bd7384a37c 658
grzemich 0:d7bd7384a37c 659 /*
grzemich 0:d7bd7384a37c 660 * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
grzemich 0:d7bd7384a37c 661 * is harmless
grzemich 0:d7bd7384a37c 662 */
grzemich 0:d7bd7384a37c 663 if (last_unsent == NULL) {
grzemich 0:d7bd7384a37c 664 pcb->unsent = queue;
grzemich 0:d7bd7384a37c 665 } else {
grzemich 0:d7bd7384a37c 666 last_unsent->next = queue;
grzemich 0:d7bd7384a37c 667 }
grzemich 0:d7bd7384a37c 668
grzemich 0:d7bd7384a37c 669 /*
grzemich 0:d7bd7384a37c 670 * Finally update the pcb state.
grzemich 0:d7bd7384a37c 671 */
grzemich 0:d7bd7384a37c 672 pcb->snd_lbb += len;
grzemich 0:d7bd7384a37c 673 pcb->snd_buf -= len;
grzemich 0:d7bd7384a37c 674 pcb->snd_queuelen = queuelen;
grzemich 0:d7bd7384a37c 675
grzemich 0:d7bd7384a37c 676 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
grzemich 0:d7bd7384a37c 677 pcb->snd_queuelen));
grzemich 0:d7bd7384a37c 678 if (pcb->snd_queuelen != 0) {
grzemich 0:d7bd7384a37c 679 LWIP_ASSERT("tcp_write: valid queue length",
grzemich 0:d7bd7384a37c 680 pcb->unacked != NULL || pcb->unsent != NULL);
grzemich 0:d7bd7384a37c 681 }
grzemich 0:d7bd7384a37c 682
grzemich 0:d7bd7384a37c 683 /* Set the PSH flag in the last segment that we enqueued. */
grzemich 0:d7bd7384a37c 684 if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
grzemich 0:d7bd7384a37c 685 TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
grzemich 0:d7bd7384a37c 686 }
grzemich 0:d7bd7384a37c 687
grzemich 0:d7bd7384a37c 688 return ERR_OK;
grzemich 0:d7bd7384a37c 689 memerr:
grzemich 0:d7bd7384a37c 690 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 691 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 692
grzemich 0:d7bd7384a37c 693 if (concat_p != NULL) {
grzemich 0:d7bd7384a37c 694 pbuf_free(concat_p);
grzemich 0:d7bd7384a37c 695 }
grzemich 0:d7bd7384a37c 696 if (queue != NULL) {
grzemich 0:d7bd7384a37c 697 tcp_segs_free(queue);
grzemich 0:d7bd7384a37c 698 }
grzemich 0:d7bd7384a37c 699 if (pcb->snd_queuelen != 0) {
grzemich 0:d7bd7384a37c 700 LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
grzemich 0:d7bd7384a37c 701 pcb->unsent != NULL);
grzemich 0:d7bd7384a37c 702 }
grzemich 0:d7bd7384a37c 703 LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
grzemich 0:d7bd7384a37c 704 return ERR_MEM;
grzemich 0:d7bd7384a37c 705 }
grzemich 0:d7bd7384a37c 706
grzemich 0:d7bd7384a37c 707 /**
grzemich 0:d7bd7384a37c 708 * Enqueue TCP options for transmission.
grzemich 0:d7bd7384a37c 709 *
grzemich 0:d7bd7384a37c 710 * Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
grzemich 0:d7bd7384a37c 711 *
grzemich 0:d7bd7384a37c 712 * @param pcb Protocol control block for the TCP connection.
grzemich 0:d7bd7384a37c 713 * @param flags TCP header flags to set in the outgoing segment.
grzemich 0:d7bd7384a37c 714 * @param optdata pointer to TCP options, or NULL.
grzemich 0:d7bd7384a37c 715 * @param optlen length of TCP options in bytes.
grzemich 0:d7bd7384a37c 716 */
grzemich 0:d7bd7384a37c 717 err_t
grzemich 0:d7bd7384a37c 718 tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
grzemich 0:d7bd7384a37c 719 {
grzemich 0:d7bd7384a37c 720 struct pbuf *p;
grzemich 0:d7bd7384a37c 721 struct tcp_seg *seg;
grzemich 0:d7bd7384a37c 722 u8_t optflags = 0;
grzemich 0:d7bd7384a37c 723 u8_t optlen = 0;
grzemich 0:d7bd7384a37c 724
grzemich 0:d7bd7384a37c 725 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
grzemich 0:d7bd7384a37c 726
grzemich 0:d7bd7384a37c 727 LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
grzemich 0:d7bd7384a37c 728 (flags & (TCP_SYN | TCP_FIN)) != 0);
grzemich 0:d7bd7384a37c 729
grzemich 0:d7bd7384a37c 730 /* check for configured max queuelen and possible overflow */
grzemich 0:d7bd7384a37c 731 if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
grzemich 0:d7bd7384a37c 732 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
grzemich 0:d7bd7384a37c 733 pcb->snd_queuelen, TCP_SND_QUEUELEN));
grzemich 0:d7bd7384a37c 734 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 735 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 736 return ERR_MEM;
grzemich 0:d7bd7384a37c 737 }
grzemich 0:d7bd7384a37c 738
grzemich 0:d7bd7384a37c 739 if (flags & TCP_SYN) {
grzemich 0:d7bd7384a37c 740 optflags = TF_SEG_OPTS_MSS;
grzemich 0:d7bd7384a37c 741 }
grzemich 0:d7bd7384a37c 742 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 743 if ((pcb->flags & TF_TIMESTAMP)) {
grzemich 0:d7bd7384a37c 744 optflags |= TF_SEG_OPTS_TS;
grzemich 0:d7bd7384a37c 745 }
grzemich 0:d7bd7384a37c 746 #endif /* LWIP_TCP_TIMESTAMPS */
grzemich 0:d7bd7384a37c 747 optlen = LWIP_TCP_OPT_LENGTH(optflags);
grzemich 0:d7bd7384a37c 748
grzemich 0:d7bd7384a37c 749 /* tcp_enqueue_flags is always called with either SYN or FIN in flags.
grzemich 0:d7bd7384a37c 750 * We need one available snd_buf byte to do that.
grzemich 0:d7bd7384a37c 751 * This means we can't send FIN while snd_buf==0. A better fix would be to
grzemich 0:d7bd7384a37c 752 * not include SYN and FIN sequence numbers in the snd_buf count. */
grzemich 0:d7bd7384a37c 753 if (pcb->snd_buf == 0) {
grzemich 0:d7bd7384a37c 754 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: no send buffer available\n"));
grzemich 0:d7bd7384a37c 755 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 756 return ERR_MEM;
grzemich 0:d7bd7384a37c 757 }
grzemich 0:d7bd7384a37c 758
grzemich 0:d7bd7384a37c 759 /* Allocate pbuf with room for TCP header + options */
grzemich 0:d7bd7384a37c 760 if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
grzemich 0:d7bd7384a37c 761 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 762 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 763 return ERR_MEM;
grzemich 0:d7bd7384a37c 764 }
grzemich 0:d7bd7384a37c 765 LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
grzemich 0:d7bd7384a37c 766 (p->len >= optlen));
grzemich 0:d7bd7384a37c 767
grzemich 0:d7bd7384a37c 768 /* Allocate memory for tcp_seg, and fill in fields. */
grzemich 0:d7bd7384a37c 769 if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
grzemich 0:d7bd7384a37c 770 pcb->flags |= TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 771 TCP_STATS_INC(tcp.memerr);
grzemich 0:d7bd7384a37c 772 return ERR_MEM;
grzemich 0:d7bd7384a37c 773 }
grzemich 0:d7bd7384a37c 774 LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
grzemich 0:d7bd7384a37c 775 LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
grzemich 0:d7bd7384a37c 776
grzemich 0:d7bd7384a37c 777 LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
grzemich 0:d7bd7384a37c 778 ("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
grzemich 0:d7bd7384a37c 779 ntohl(seg->tcphdr->seqno),
grzemich 0:d7bd7384a37c 780 ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
grzemich 0:d7bd7384a37c 781 (u16_t)flags));
grzemich 0:d7bd7384a37c 782
grzemich 0:d7bd7384a37c 783 /* Now append seg to pcb->unsent queue */
grzemich 0:d7bd7384a37c 784 if (pcb->unsent == NULL) {
grzemich 0:d7bd7384a37c 785 pcb->unsent = seg;
grzemich 0:d7bd7384a37c 786 } else {
grzemich 0:d7bd7384a37c 787 struct tcp_seg *useg;
grzemich 0:d7bd7384a37c 788 for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
grzemich 0:d7bd7384a37c 789 useg->next = seg;
grzemich 0:d7bd7384a37c 790 }
grzemich 0:d7bd7384a37c 791 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 792 /* The new unsent tail has no space */
grzemich 0:d7bd7384a37c 793 pcb->unsent_oversize = 0;
grzemich 0:d7bd7384a37c 794 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 795
grzemich 0:d7bd7384a37c 796 /* SYN and FIN bump the sequence number */
grzemich 0:d7bd7384a37c 797 if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
grzemich 0:d7bd7384a37c 798 pcb->snd_lbb++;
grzemich 0:d7bd7384a37c 799 /* optlen does not influence snd_buf */
grzemich 0:d7bd7384a37c 800 pcb->snd_buf--;
grzemich 0:d7bd7384a37c 801 }
grzemich 0:d7bd7384a37c 802 if (flags & TCP_FIN) {
grzemich 0:d7bd7384a37c 803 pcb->flags |= TF_FIN;
grzemich 0:d7bd7384a37c 804 }
grzemich 0:d7bd7384a37c 805
grzemich 0:d7bd7384a37c 806 /* update number of segments on the queues */
grzemich 0:d7bd7384a37c 807 pcb->snd_queuelen += pbuf_clen(seg->p);
grzemich 0:d7bd7384a37c 808 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
grzemich 0:d7bd7384a37c 809 if (pcb->snd_queuelen != 0) {
grzemich 0:d7bd7384a37c 810 LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
grzemich 0:d7bd7384a37c 811 pcb->unacked != NULL || pcb->unsent != NULL);
grzemich 0:d7bd7384a37c 812 }
grzemich 0:d7bd7384a37c 813
grzemich 0:d7bd7384a37c 814 return ERR_OK;
grzemich 0:d7bd7384a37c 815 }
grzemich 0:d7bd7384a37c 816
grzemich 0:d7bd7384a37c 817
grzemich 0:d7bd7384a37c 818 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 819 /* Build a timestamp option (12 bytes long) at the specified options pointer)
grzemich 0:d7bd7384a37c 820 *
grzemich 0:d7bd7384a37c 821 * @param pcb tcp_pcb
grzemich 0:d7bd7384a37c 822 * @param opts option pointer where to store the timestamp option
grzemich 0:d7bd7384a37c 823 */
grzemich 0:d7bd7384a37c 824 static void
grzemich 0:d7bd7384a37c 825 tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
grzemich 0:d7bd7384a37c 826 {
grzemich 0:d7bd7384a37c 827 /* Pad with two NOP options to make everything nicely aligned */
grzemich 0:d7bd7384a37c 828 opts[0] = PP_HTONL(0x0101080A);
grzemich 0:d7bd7384a37c 829 opts[1] = htonl(sys_now());
grzemich 0:d7bd7384a37c 830 opts[2] = htonl(pcb->ts_recent);
grzemich 0:d7bd7384a37c 831 }
grzemich 0:d7bd7384a37c 832 #endif
grzemich 0:d7bd7384a37c 833
grzemich 0:d7bd7384a37c 834 /** Send an ACK without data.
grzemich 0:d7bd7384a37c 835 *
grzemich 0:d7bd7384a37c 836 * @param pcb Protocol control block for the TCP connection to send the ACK
grzemich 0:d7bd7384a37c 837 */
grzemich 0:d7bd7384a37c 838 err_t
grzemich 0:d7bd7384a37c 839 tcp_send_empty_ack(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 840 {
grzemich 0:d7bd7384a37c 841 struct pbuf *p;
grzemich 0:d7bd7384a37c 842 struct tcp_hdr *tcphdr;
grzemich 0:d7bd7384a37c 843 u8_t optlen = 0;
grzemich 0:d7bd7384a37c 844
grzemich 0:d7bd7384a37c 845 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 846 if (pcb->flags & TF_TIMESTAMP) {
grzemich 0:d7bd7384a37c 847 optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
grzemich 0:d7bd7384a37c 848 }
grzemich 0:d7bd7384a37c 849 #endif
grzemich 0:d7bd7384a37c 850
grzemich 0:d7bd7384a37c 851 p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
grzemich 0:d7bd7384a37c 852 if (p == NULL) {
grzemich 0:d7bd7384a37c 853 LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
grzemich 0:d7bd7384a37c 854 return ERR_BUF;
grzemich 0:d7bd7384a37c 855 }
grzemich 0:d7bd7384a37c 856 tcphdr = (struct tcp_hdr *)p->payload;
grzemich 0:d7bd7384a37c 857 LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
grzemich 0:d7bd7384a37c 858 ("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
grzemich 0:d7bd7384a37c 859 /* remove ACK flags from the PCB, as we send an empty ACK now */
grzemich 0:d7bd7384a37c 860 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
grzemich 0:d7bd7384a37c 861
grzemich 0:d7bd7384a37c 862 /* NB. MSS option is only sent on SYNs, so ignore it here */
grzemich 0:d7bd7384a37c 863 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 864 pcb->ts_lastacksent = pcb->rcv_nxt;
grzemich 0:d7bd7384a37c 865
grzemich 0:d7bd7384a37c 866 if (pcb->flags & TF_TIMESTAMP) {
grzemich 0:d7bd7384a37c 867 tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
grzemich 0:d7bd7384a37c 868 }
grzemich 0:d7bd7384a37c 869 #endif
grzemich 0:d7bd7384a37c 870
grzemich 0:d7bd7384a37c 871 #if CHECKSUM_GEN_TCP
grzemich 0:d7bd7384a37c 872 tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
grzemich 0:d7bd7384a37c 873 IP_PROTO_TCP, p->tot_len);
grzemich 0:d7bd7384a37c 874 #endif
grzemich 0:d7bd7384a37c 875 #if LWIP_NETIF_HWADDRHINT
grzemich 0:d7bd7384a37c 876 ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
grzemich 0:d7bd7384a37c 877 IP_PROTO_TCP, &(pcb->addr_hint));
grzemich 0:d7bd7384a37c 878 #else /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 879 ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
grzemich 0:d7bd7384a37c 880 IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 881 #endif /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 882 pbuf_free(p);
grzemich 0:d7bd7384a37c 883
grzemich 0:d7bd7384a37c 884 return ERR_OK;
grzemich 0:d7bd7384a37c 885 }
grzemich 0:d7bd7384a37c 886
grzemich 0:d7bd7384a37c 887 /**
grzemich 0:d7bd7384a37c 888 * Find out what we can send and send it
grzemich 0:d7bd7384a37c 889 *
grzemich 0:d7bd7384a37c 890 * @param pcb Protocol control block for the TCP connection to send data
grzemich 0:d7bd7384a37c 891 * @return ERR_OK if data has been sent or nothing to send
grzemich 0:d7bd7384a37c 892 * another err_t on error
grzemich 0:d7bd7384a37c 893 */
grzemich 0:d7bd7384a37c 894 err_t
grzemich 0:d7bd7384a37c 895 tcp_output(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 896 {
grzemich 0:d7bd7384a37c 897 struct tcp_seg *seg, *useg;
grzemich 0:d7bd7384a37c 898 u32_t wnd, snd_nxt;
grzemich 0:d7bd7384a37c 899 #if TCP_CWND_DEBUG
grzemich 0:d7bd7384a37c 900 s16_t i = 0;
grzemich 0:d7bd7384a37c 901 #endif /* TCP_CWND_DEBUG */
grzemich 0:d7bd7384a37c 902
grzemich 0:d7bd7384a37c 903 /* First, check if we are invoked by the TCP input processing
grzemich 0:d7bd7384a37c 904 code. If so, we do not output anything. Instead, we rely on the
grzemich 0:d7bd7384a37c 905 input processing code to call us when input processing is done
grzemich 0:d7bd7384a37c 906 with. */
grzemich 0:d7bd7384a37c 907 if (tcp_input_pcb == pcb) {
grzemich 0:d7bd7384a37c 908 return ERR_OK;
grzemich 0:d7bd7384a37c 909 }
grzemich 0:d7bd7384a37c 910
grzemich 0:d7bd7384a37c 911 wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
grzemich 0:d7bd7384a37c 912
grzemich 0:d7bd7384a37c 913 seg = pcb->unsent;
grzemich 0:d7bd7384a37c 914
grzemich 0:d7bd7384a37c 915 /* If the TF_ACK_NOW flag is set and no data will be sent (either
grzemich 0:d7bd7384a37c 916 * because the ->unsent queue is empty or because the window does
grzemich 0:d7bd7384a37c 917 * not allow it), construct an empty ACK segment and send it.
grzemich 0:d7bd7384a37c 918 *
grzemich 0:d7bd7384a37c 919 * If data is to be sent, we will just piggyback the ACK (see below).
grzemich 0:d7bd7384a37c 920 */
grzemich 0:d7bd7384a37c 921 if (pcb->flags & TF_ACK_NOW &&
grzemich 0:d7bd7384a37c 922 (seg == NULL ||
grzemich 0:d7bd7384a37c 923 ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
grzemich 0:d7bd7384a37c 924 return tcp_send_empty_ack(pcb);
grzemich 0:d7bd7384a37c 925 }
grzemich 0:d7bd7384a37c 926
grzemich 0:d7bd7384a37c 927 /* useg should point to last segment on unacked queue */
grzemich 0:d7bd7384a37c 928 useg = pcb->unacked;
grzemich 0:d7bd7384a37c 929 if (useg != NULL) {
grzemich 0:d7bd7384a37c 930 for (; useg->next != NULL; useg = useg->next);
grzemich 0:d7bd7384a37c 931 }
grzemich 0:d7bd7384a37c 932
grzemich 0:d7bd7384a37c 933 #if TCP_OUTPUT_DEBUG
grzemich 0:d7bd7384a37c 934 if (seg == NULL) {
grzemich 0:d7bd7384a37c 935 LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
grzemich 0:d7bd7384a37c 936 (void*)pcb->unsent));
grzemich 0:d7bd7384a37c 937 }
grzemich 0:d7bd7384a37c 938 #endif /* TCP_OUTPUT_DEBUG */
grzemich 0:d7bd7384a37c 939 #if TCP_CWND_DEBUG
grzemich 0:d7bd7384a37c 940 if (seg == NULL) {
grzemich 0:d7bd7384a37c 941 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
grzemich 0:d7bd7384a37c 942 ", cwnd %"U16_F", wnd %"U32_F
grzemich 0:d7bd7384a37c 943 ", seg == NULL, ack %"U32_F"\n",
grzemich 0:d7bd7384a37c 944 pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
grzemich 0:d7bd7384a37c 945 } else {
grzemich 0:d7bd7384a37c 946 LWIP_DEBUGF(TCP_CWND_DEBUG,
grzemich 0:d7bd7384a37c 947 ("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
grzemich 0:d7bd7384a37c 948 ", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
grzemich 0:d7bd7384a37c 949 pcb->snd_wnd, pcb->cwnd, wnd,
grzemich 0:d7bd7384a37c 950 ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
grzemich 0:d7bd7384a37c 951 ntohl(seg->tcphdr->seqno), pcb->lastack));
grzemich 0:d7bd7384a37c 952 }
grzemich 0:d7bd7384a37c 953 #endif /* TCP_CWND_DEBUG */
grzemich 0:d7bd7384a37c 954 /* data available and window allows it to be sent? */
grzemich 0:d7bd7384a37c 955 while (seg != NULL &&
grzemich 0:d7bd7384a37c 956 ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
grzemich 0:d7bd7384a37c 957 LWIP_ASSERT("RST not expected here!",
grzemich 0:d7bd7384a37c 958 (TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
grzemich 0:d7bd7384a37c 959 /* Stop sending if the nagle algorithm would prevent it
grzemich 0:d7bd7384a37c 960 * Don't stop:
grzemich 0:d7bd7384a37c 961 * - if tcp_write had a memory error before (prevent delayed ACK timeout) or
grzemich 0:d7bd7384a37c 962 * - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
grzemich 0:d7bd7384a37c 963 * either seg->next != NULL or pcb->unacked == NULL;
grzemich 0:d7bd7384a37c 964 * RST is no sent using tcp_write/tcp_output.
grzemich 0:d7bd7384a37c 965 */
grzemich 0:d7bd7384a37c 966 if((tcp_do_output_nagle(pcb) == 0) &&
grzemich 0:d7bd7384a37c 967 ((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)){
grzemich 0:d7bd7384a37c 968 break;
grzemich 0:d7bd7384a37c 969 }
grzemich 0:d7bd7384a37c 970 #if TCP_CWND_DEBUG
grzemich 0:d7bd7384a37c 971 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",
grzemich 0:d7bd7384a37c 972 pcb->snd_wnd, pcb->cwnd, wnd,
grzemich 0:d7bd7384a37c 973 ntohl(seg->tcphdr->seqno) + seg->len -
grzemich 0:d7bd7384a37c 974 pcb->lastack,
grzemich 0:d7bd7384a37c 975 ntohl(seg->tcphdr->seqno), pcb->lastack, i));
grzemich 0:d7bd7384a37c 976 ++i;
grzemich 0:d7bd7384a37c 977 #endif /* TCP_CWND_DEBUG */
grzemich 0:d7bd7384a37c 978
grzemich 0:d7bd7384a37c 979 pcb->unsent = seg->next;
grzemich 0:d7bd7384a37c 980
grzemich 0:d7bd7384a37c 981 if (pcb->state != SYN_SENT) {
grzemich 0:d7bd7384a37c 982 TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
grzemich 0:d7bd7384a37c 983 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
grzemich 0:d7bd7384a37c 984 }
grzemich 0:d7bd7384a37c 985
grzemich 0:d7bd7384a37c 986 tcp_output_segment(seg, pcb);
grzemich 0:d7bd7384a37c 987 snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
grzemich 0:d7bd7384a37c 988 if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
grzemich 0:d7bd7384a37c 989 pcb->snd_nxt = snd_nxt;
grzemich 0:d7bd7384a37c 990 }
grzemich 0:d7bd7384a37c 991 /* put segment on unacknowledged list if length > 0 */
grzemich 0:d7bd7384a37c 992 if (TCP_TCPLEN(seg) > 0) {
grzemich 0:d7bd7384a37c 993 seg->next = NULL;
grzemich 0:d7bd7384a37c 994 /* unacked list is empty? */
grzemich 0:d7bd7384a37c 995 if (pcb->unacked == NULL) {
grzemich 0:d7bd7384a37c 996 pcb->unacked = seg;
grzemich 0:d7bd7384a37c 997 useg = seg;
grzemich 0:d7bd7384a37c 998 /* unacked list is not empty? */
grzemich 0:d7bd7384a37c 999 } else {
grzemich 0:d7bd7384a37c 1000 /* In the case of fast retransmit, the packet should not go to the tail
grzemich 0:d7bd7384a37c 1001 * of the unacked queue, but rather somewhere before it. We need to check for
grzemich 0:d7bd7384a37c 1002 * this case. -STJ Jul 27, 2004 */
grzemich 0:d7bd7384a37c 1003 if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
grzemich 0:d7bd7384a37c 1004 /* add segment to before tail of unacked list, keeping the list sorted */
grzemich 0:d7bd7384a37c 1005 struct tcp_seg **cur_seg = &(pcb->unacked);
grzemich 0:d7bd7384a37c 1006 while (*cur_seg &&
grzemich 0:d7bd7384a37c 1007 TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
grzemich 0:d7bd7384a37c 1008 cur_seg = &((*cur_seg)->next );
grzemich 0:d7bd7384a37c 1009 }
grzemich 0:d7bd7384a37c 1010 seg->next = (*cur_seg);
grzemich 0:d7bd7384a37c 1011 (*cur_seg) = seg;
grzemich 0:d7bd7384a37c 1012 } else {
grzemich 0:d7bd7384a37c 1013 /* add segment to tail of unacked list */
grzemich 0:d7bd7384a37c 1014 useg->next = seg;
grzemich 0:d7bd7384a37c 1015 useg = useg->next;
grzemich 0:d7bd7384a37c 1016 }
grzemich 0:d7bd7384a37c 1017 }
grzemich 0:d7bd7384a37c 1018 /* do not queue empty segments on the unacked list */
grzemich 0:d7bd7384a37c 1019 } else {
grzemich 0:d7bd7384a37c 1020 tcp_seg_free(seg);
grzemich 0:d7bd7384a37c 1021 }
grzemich 0:d7bd7384a37c 1022 seg = pcb->unsent;
grzemich 0:d7bd7384a37c 1023 }
grzemich 0:d7bd7384a37c 1024 #if TCP_OVERSIZE
grzemich 0:d7bd7384a37c 1025 if (pcb->unsent == NULL) {
grzemich 0:d7bd7384a37c 1026 /* last unsent has been removed, reset unsent_oversize */
grzemich 0:d7bd7384a37c 1027 pcb->unsent_oversize = 0;
grzemich 0:d7bd7384a37c 1028 }
grzemich 0:d7bd7384a37c 1029 #endif /* TCP_OVERSIZE */
grzemich 0:d7bd7384a37c 1030
grzemich 0:d7bd7384a37c 1031 if (seg != NULL && pcb->persist_backoff == 0 &&
grzemich 0:d7bd7384a37c 1032 ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
grzemich 0:d7bd7384a37c 1033 /* prepare for persist timer */
grzemich 0:d7bd7384a37c 1034 pcb->persist_cnt = 0;
grzemich 0:d7bd7384a37c 1035 pcb->persist_backoff = 1;
grzemich 0:d7bd7384a37c 1036 }
grzemich 0:d7bd7384a37c 1037
grzemich 0:d7bd7384a37c 1038 pcb->flags &= ~TF_NAGLEMEMERR;
grzemich 0:d7bd7384a37c 1039 return ERR_OK;
grzemich 0:d7bd7384a37c 1040 }
grzemich 0:d7bd7384a37c 1041
grzemich 0:d7bd7384a37c 1042 /**
grzemich 0:d7bd7384a37c 1043 * Called by tcp_output() to actually send a TCP segment over IP.
grzemich 0:d7bd7384a37c 1044 *
grzemich 0:d7bd7384a37c 1045 * @param seg the tcp_seg to send
grzemich 0:d7bd7384a37c 1046 * @param pcb the tcp_pcb for the TCP connection used to send the segment
grzemich 0:d7bd7384a37c 1047 */
grzemich 0:d7bd7384a37c 1048 static void
grzemich 0:d7bd7384a37c 1049 tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1050 {
grzemich 0:d7bd7384a37c 1051 u16_t len;
grzemich 0:d7bd7384a37c 1052 struct netif *netif;
grzemich 0:d7bd7384a37c 1053 u32_t *opts;
grzemich 0:d7bd7384a37c 1054
grzemich 0:d7bd7384a37c 1055 /** @bug Exclude retransmitted segments from this count. */
grzemich 0:d7bd7384a37c 1056 snmp_inc_tcpoutsegs();
grzemich 0:d7bd7384a37c 1057
grzemich 0:d7bd7384a37c 1058 /* The TCP header has already been constructed, but the ackno and
grzemich 0:d7bd7384a37c 1059 wnd fields remain. */
grzemich 0:d7bd7384a37c 1060 seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
grzemich 0:d7bd7384a37c 1061
grzemich 0:d7bd7384a37c 1062 /* advertise our receive window size in this TCP segment */
grzemich 0:d7bd7384a37c 1063 seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
grzemich 0:d7bd7384a37c 1064
grzemich 0:d7bd7384a37c 1065 pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
grzemich 0:d7bd7384a37c 1066
grzemich 0:d7bd7384a37c 1067 /* Add any requested options. NB MSS option is only set on SYN
grzemich 0:d7bd7384a37c 1068 packets, so ignore it here */
grzemich 0:d7bd7384a37c 1069 LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
grzemich 0:d7bd7384a37c 1070 opts = (u32_t *)(void *)(seg->tcphdr + 1);
grzemich 0:d7bd7384a37c 1071 if (seg->flags & TF_SEG_OPTS_MSS) {
grzemich 0:d7bd7384a37c 1072 TCP_BUILD_MSS_OPTION(*opts);
grzemich 0:d7bd7384a37c 1073 opts += 1;
grzemich 0:d7bd7384a37c 1074 }
grzemich 0:d7bd7384a37c 1075 #if LWIP_TCP_TIMESTAMPS
grzemich 0:d7bd7384a37c 1076 pcb->ts_lastacksent = pcb->rcv_nxt;
grzemich 0:d7bd7384a37c 1077
grzemich 0:d7bd7384a37c 1078 if (seg->flags & TF_SEG_OPTS_TS) {
grzemich 0:d7bd7384a37c 1079 tcp_build_timestamp_option(pcb, opts);
grzemich 0:d7bd7384a37c 1080 opts += 3;
grzemich 0:d7bd7384a37c 1081 }
grzemich 0:d7bd7384a37c 1082 #endif
grzemich 0:d7bd7384a37c 1083
grzemich 0:d7bd7384a37c 1084 /* Set retransmission timer running if it is not currently enabled
grzemich 0:d7bd7384a37c 1085 This must be set before checking the route. */
grzemich 0:d7bd7384a37c 1086 if (pcb->rtime == -1) {
grzemich 0:d7bd7384a37c 1087 pcb->rtime = 0;
grzemich 0:d7bd7384a37c 1088 }
grzemich 0:d7bd7384a37c 1089
grzemich 0:d7bd7384a37c 1090 /* If we don't have a local IP address, we get one by
grzemich 0:d7bd7384a37c 1091 calling ip_route(). */
grzemich 0:d7bd7384a37c 1092 if (ip_addr_isany(&(pcb->local_ip))) {
grzemich 0:d7bd7384a37c 1093 netif = ip_route(&(pcb->remote_ip));
grzemich 0:d7bd7384a37c 1094 if (netif == NULL) {
grzemich 0:d7bd7384a37c 1095 return;
grzemich 0:d7bd7384a37c 1096 }
grzemich 0:d7bd7384a37c 1097 ip_addr_copy(pcb->local_ip, netif->ip_addr);
grzemich 0:d7bd7384a37c 1098 }
grzemich 0:d7bd7384a37c 1099
grzemich 0:d7bd7384a37c 1100 if (pcb->rttest == 0) {
grzemich 0:d7bd7384a37c 1101 pcb->rttest = tcp_ticks;
grzemich 0:d7bd7384a37c 1102 pcb->rtseq = ntohl(seg->tcphdr->seqno);
grzemich 0:d7bd7384a37c 1103
grzemich 0:d7bd7384a37c 1104 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
grzemich 0:d7bd7384a37c 1105 }
grzemich 0:d7bd7384a37c 1106 LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
grzemich 0:d7bd7384a37c 1107 htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
grzemich 0:d7bd7384a37c 1108 seg->len));
grzemich 0:d7bd7384a37c 1109
grzemich 0:d7bd7384a37c 1110 len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
grzemich 0:d7bd7384a37c 1111
grzemich 0:d7bd7384a37c 1112 seg->p->len -= len;
grzemich 0:d7bd7384a37c 1113 seg->p->tot_len -= len;
grzemich 0:d7bd7384a37c 1114
grzemich 0:d7bd7384a37c 1115 seg->p->payload = seg->tcphdr;
grzemich 0:d7bd7384a37c 1116
grzemich 0:d7bd7384a37c 1117 seg->tcphdr->chksum = 0;
grzemich 0:d7bd7384a37c 1118 #if CHECKSUM_GEN_TCP
grzemich 0:d7bd7384a37c 1119 #if TCP_CHECKSUM_ON_COPY
grzemich 0:d7bd7384a37c 1120 {
grzemich 0:d7bd7384a37c 1121 u32_t acc;
grzemich 0:d7bd7384a37c 1122 #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
grzemich 0:d7bd7384a37c 1123 u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
grzemich 0:d7bd7384a37c 1124 &(pcb->remote_ip),
grzemich 0:d7bd7384a37c 1125 IP_PROTO_TCP, seg->p->tot_len);
grzemich 0:d7bd7384a37c 1126 #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
grzemich 0:d7bd7384a37c 1127 if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
grzemich 0:d7bd7384a37c 1128 LWIP_ASSERT("data included but not checksummed",
grzemich 0:d7bd7384a37c 1129 seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
grzemich 0:d7bd7384a37c 1130 }
grzemich 0:d7bd7384a37c 1131
grzemich 0:d7bd7384a37c 1132 /* rebuild TCP header checksum (TCP header changes for retransmissions!) */
grzemich 0:d7bd7384a37c 1133 acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
grzemich 0:d7bd7384a37c 1134 &(pcb->remote_ip),
grzemich 0:d7bd7384a37c 1135 IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
grzemich 0:d7bd7384a37c 1136 /* add payload checksum */
grzemich 0:d7bd7384a37c 1137 if (seg->chksum_swapped) {
grzemich 0:d7bd7384a37c 1138 seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
grzemich 0:d7bd7384a37c 1139 seg->chksum_swapped = 0;
grzemich 0:d7bd7384a37c 1140 }
grzemich 0:d7bd7384a37c 1141 acc += (u16_t)~(seg->chksum);
grzemich 0:d7bd7384a37c 1142 seg->tcphdr->chksum = FOLD_U32T(acc);
grzemich 0:d7bd7384a37c 1143 #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
grzemich 0:d7bd7384a37c 1144 if (chksum_slow != seg->tcphdr->chksum) {
grzemich 0:d7bd7384a37c 1145 LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING,
grzemich 0:d7bd7384a37c 1146 ("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
grzemich 0:d7bd7384a37c 1147 seg->tcphdr->chksum, chksum_slow));
grzemich 0:d7bd7384a37c 1148 seg->tcphdr->chksum = chksum_slow;
grzemich 0:d7bd7384a37c 1149 }
grzemich 0:d7bd7384a37c 1150 #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
grzemich 0:d7bd7384a37c 1151 }
grzemich 0:d7bd7384a37c 1152 #else /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 1153 seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
grzemich 0:d7bd7384a37c 1154 &(pcb->remote_ip),
grzemich 0:d7bd7384a37c 1155 IP_PROTO_TCP, seg->p->tot_len);
grzemich 0:d7bd7384a37c 1156 #endif /* TCP_CHECKSUM_ON_COPY */
grzemich 0:d7bd7384a37c 1157 #endif /* CHECKSUM_GEN_TCP */
grzemich 0:d7bd7384a37c 1158 TCP_STATS_INC(tcp.xmit);
grzemich 0:d7bd7384a37c 1159
grzemich 0:d7bd7384a37c 1160 #if LWIP_NETIF_HWADDRHINT
grzemich 0:d7bd7384a37c 1161 ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
grzemich 0:d7bd7384a37c 1162 IP_PROTO_TCP, &(pcb->addr_hint));
grzemich 0:d7bd7384a37c 1163 #else /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1164 ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
grzemich 0:d7bd7384a37c 1165 IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 1166 #endif /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1167 }
grzemich 0:d7bd7384a37c 1168
grzemich 0:d7bd7384a37c 1169 /**
grzemich 0:d7bd7384a37c 1170 * Send a TCP RESET packet (empty segment with RST flag set) either to
grzemich 0:d7bd7384a37c 1171 * abort a connection or to show that there is no matching local connection
grzemich 0:d7bd7384a37c 1172 * for a received segment.
grzemich 0:d7bd7384a37c 1173 *
grzemich 0:d7bd7384a37c 1174 * Called by tcp_abort() (to abort a local connection), tcp_input() (if no
grzemich 0:d7bd7384a37c 1175 * matching local pcb was found), tcp_listen_input() (if incoming segment
grzemich 0:d7bd7384a37c 1176 * has ACK flag set) and tcp_process() (received segment in the wrong state)
grzemich 0:d7bd7384a37c 1177 *
grzemich 0:d7bd7384a37c 1178 * Since a RST segment is in most cases not sent for an active connection,
grzemich 0:d7bd7384a37c 1179 * tcp_rst() has a number of arguments that are taken from a tcp_pcb for
grzemich 0:d7bd7384a37c 1180 * most other segment output functions.
grzemich 0:d7bd7384a37c 1181 *
grzemich 0:d7bd7384a37c 1182 * @param seqno the sequence number to use for the outgoing segment
grzemich 0:d7bd7384a37c 1183 * @param ackno the acknowledge number to use for the outgoing segment
grzemich 0:d7bd7384a37c 1184 * @param local_ip the local IP address to send the segment from
grzemich 0:d7bd7384a37c 1185 * @param remote_ip the remote IP address to send the segment to
grzemich 0:d7bd7384a37c 1186 * @param local_port the local TCP port to send the segment from
grzemich 0:d7bd7384a37c 1187 * @param remote_port the remote TCP port to send the segment to
grzemich 0:d7bd7384a37c 1188 */
grzemich 0:d7bd7384a37c 1189 void
grzemich 0:d7bd7384a37c 1190 tcp_rst(u32_t seqno, u32_t ackno,
grzemich 0:d7bd7384a37c 1191 ip_addr_t *local_ip, ip_addr_t *remote_ip,
grzemich 0:d7bd7384a37c 1192 u16_t local_port, u16_t remote_port)
grzemich 0:d7bd7384a37c 1193 {
grzemich 0:d7bd7384a37c 1194 struct pbuf *p;
grzemich 0:d7bd7384a37c 1195 struct tcp_hdr *tcphdr;
grzemich 0:d7bd7384a37c 1196 p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
grzemich 0:d7bd7384a37c 1197 if (p == NULL) {
grzemich 0:d7bd7384a37c 1198 LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
grzemich 0:d7bd7384a37c 1199 return;
grzemich 0:d7bd7384a37c 1200 }
grzemich 0:d7bd7384a37c 1201 LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
grzemich 0:d7bd7384a37c 1202 (p->len >= sizeof(struct tcp_hdr)));
grzemich 0:d7bd7384a37c 1203
grzemich 0:d7bd7384a37c 1204 tcphdr = (struct tcp_hdr *)p->payload;
grzemich 0:d7bd7384a37c 1205 tcphdr->src = htons(local_port);
grzemich 0:d7bd7384a37c 1206 tcphdr->dest = htons(remote_port);
grzemich 0:d7bd7384a37c 1207 tcphdr->seqno = htonl(seqno);
grzemich 0:d7bd7384a37c 1208 tcphdr->ackno = htonl(ackno);
grzemich 0:d7bd7384a37c 1209 TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST | TCP_ACK);
grzemich 0:d7bd7384a37c 1210 tcphdr->wnd = PP_HTONS(TCP_WND);
grzemich 0:d7bd7384a37c 1211 tcphdr->chksum = 0;
grzemich 0:d7bd7384a37c 1212 tcphdr->urgp = 0;
grzemich 0:d7bd7384a37c 1213
grzemich 0:d7bd7384a37c 1214 #if CHECKSUM_GEN_TCP
grzemich 0:d7bd7384a37c 1215 tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
grzemich 0:d7bd7384a37c 1216 IP_PROTO_TCP, p->tot_len);
grzemich 0:d7bd7384a37c 1217 #endif
grzemich 0:d7bd7384a37c 1218 TCP_STATS_INC(tcp.xmit);
grzemich 0:d7bd7384a37c 1219 snmp_inc_tcpoutrsts();
grzemich 0:d7bd7384a37c 1220 /* Send output with hardcoded TTL since we have no access to the pcb */
grzemich 0:d7bd7384a37c 1221 ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 1222 pbuf_free(p);
grzemich 0:d7bd7384a37c 1223 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
grzemich 0:d7bd7384a37c 1224 }
grzemich 0:d7bd7384a37c 1225
grzemich 0:d7bd7384a37c 1226 /**
grzemich 0:d7bd7384a37c 1227 * Requeue all unacked segments for retransmission
grzemich 0:d7bd7384a37c 1228 *
grzemich 0:d7bd7384a37c 1229 * Called by tcp_slowtmr() for slow retransmission.
grzemich 0:d7bd7384a37c 1230 *
grzemich 0:d7bd7384a37c 1231 * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
grzemich 0:d7bd7384a37c 1232 */
grzemich 0:d7bd7384a37c 1233 void
grzemich 0:d7bd7384a37c 1234 tcp_rexmit_rto(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1235 {
grzemich 0:d7bd7384a37c 1236 struct tcp_seg *seg;
grzemich 0:d7bd7384a37c 1237
grzemich 0:d7bd7384a37c 1238 if (pcb->unacked == NULL) {
grzemich 0:d7bd7384a37c 1239 return;
grzemich 0:d7bd7384a37c 1240 }
grzemich 0:d7bd7384a37c 1241
grzemich 0:d7bd7384a37c 1242 /* Move all unacked segments to the head of the unsent queue */
grzemich 0:d7bd7384a37c 1243 for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
grzemich 0:d7bd7384a37c 1244 /* concatenate unsent queue after unacked queue */
grzemich 0:d7bd7384a37c 1245 seg->next = pcb->unsent;
grzemich 0:d7bd7384a37c 1246 /* unsent queue is the concatenated queue (of unacked, unsent) */
grzemich 0:d7bd7384a37c 1247 pcb->unsent = pcb->unacked;
grzemich 0:d7bd7384a37c 1248 /* unacked queue is now empty */
grzemich 0:d7bd7384a37c 1249 pcb->unacked = NULL;
grzemich 0:d7bd7384a37c 1250
grzemich 0:d7bd7384a37c 1251 /* increment number of retransmissions */
grzemich 0:d7bd7384a37c 1252 ++pcb->nrtx;
grzemich 0:d7bd7384a37c 1253
grzemich 0:d7bd7384a37c 1254 /* Don't take any RTT measurements after retransmitting. */
grzemich 0:d7bd7384a37c 1255 pcb->rttest = 0;
grzemich 0:d7bd7384a37c 1256
grzemich 0:d7bd7384a37c 1257 /* Do the actual retransmission */
grzemich 0:d7bd7384a37c 1258 tcp_output(pcb);
grzemich 0:d7bd7384a37c 1259 }
grzemich 0:d7bd7384a37c 1260
grzemich 0:d7bd7384a37c 1261 /**
grzemich 0:d7bd7384a37c 1262 * Requeue the first unacked segment for retransmission
grzemich 0:d7bd7384a37c 1263 *
grzemich 0:d7bd7384a37c 1264 * Called by tcp_receive() for fast retramsmit.
grzemich 0:d7bd7384a37c 1265 *
grzemich 0:d7bd7384a37c 1266 * @param pcb the tcp_pcb for which to retransmit the first unacked segment
grzemich 0:d7bd7384a37c 1267 */
grzemich 0:d7bd7384a37c 1268 void
grzemich 0:d7bd7384a37c 1269 tcp_rexmit(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1270 {
grzemich 0:d7bd7384a37c 1271 struct tcp_seg *seg;
grzemich 0:d7bd7384a37c 1272 struct tcp_seg **cur_seg;
grzemich 0:d7bd7384a37c 1273
grzemich 0:d7bd7384a37c 1274 if (pcb->unacked == NULL) {
grzemich 0:d7bd7384a37c 1275 return;
grzemich 0:d7bd7384a37c 1276 }
grzemich 0:d7bd7384a37c 1277
grzemich 0:d7bd7384a37c 1278 /* Move the first unacked segment to the unsent queue */
grzemich 0:d7bd7384a37c 1279 /* Keep the unsent queue sorted. */
grzemich 0:d7bd7384a37c 1280 seg = pcb->unacked;
grzemich 0:d7bd7384a37c 1281 pcb->unacked = seg->next;
grzemich 0:d7bd7384a37c 1282
grzemich 0:d7bd7384a37c 1283 cur_seg = &(pcb->unsent);
grzemich 0:d7bd7384a37c 1284 while (*cur_seg &&
grzemich 0:d7bd7384a37c 1285 TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
grzemich 0:d7bd7384a37c 1286 cur_seg = &((*cur_seg)->next );
grzemich 0:d7bd7384a37c 1287 }
grzemich 0:d7bd7384a37c 1288 seg->next = *cur_seg;
grzemich 0:d7bd7384a37c 1289 *cur_seg = seg;
grzemich 0:d7bd7384a37c 1290
grzemich 0:d7bd7384a37c 1291 ++pcb->nrtx;
grzemich 0:d7bd7384a37c 1292
grzemich 0:d7bd7384a37c 1293 /* Don't take any rtt measurements after retransmitting. */
grzemich 0:d7bd7384a37c 1294 pcb->rttest = 0;
grzemich 0:d7bd7384a37c 1295
grzemich 0:d7bd7384a37c 1296 /* Do the actual retransmission. */
grzemich 0:d7bd7384a37c 1297 snmp_inc_tcpretranssegs();
grzemich 0:d7bd7384a37c 1298 /* No need to call tcp_output: we are always called from tcp_input()
grzemich 0:d7bd7384a37c 1299 and thus tcp_output directly returns. */
grzemich 0:d7bd7384a37c 1300 }
grzemich 0:d7bd7384a37c 1301
grzemich 0:d7bd7384a37c 1302
grzemich 0:d7bd7384a37c 1303 /**
grzemich 0:d7bd7384a37c 1304 * Handle retransmission after three dupacks received
grzemich 0:d7bd7384a37c 1305 *
grzemich 0:d7bd7384a37c 1306 * @param pcb the tcp_pcb for which to retransmit the first unacked segment
grzemich 0:d7bd7384a37c 1307 */
grzemich 0:d7bd7384a37c 1308 void
grzemich 0:d7bd7384a37c 1309 tcp_rexmit_fast(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1310 {
grzemich 0:d7bd7384a37c 1311 if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
grzemich 0:d7bd7384a37c 1312 /* This is fast retransmit. Retransmit the first unacked segment. */
grzemich 0:d7bd7384a37c 1313 LWIP_DEBUGF(TCP_FR_DEBUG,
grzemich 0:d7bd7384a37c 1314 ("tcp_receive: dupacks %"U16_F" (%"U32_F
grzemich 0:d7bd7384a37c 1315 "), fast retransmit %"U32_F"\n",
grzemich 0:d7bd7384a37c 1316 (u16_t)pcb->dupacks, pcb->lastack,
grzemich 0:d7bd7384a37c 1317 ntohl(pcb->unacked->tcphdr->seqno)));
grzemich 0:d7bd7384a37c 1318 tcp_rexmit(pcb);
grzemich 0:d7bd7384a37c 1319
grzemich 0:d7bd7384a37c 1320 /* Set ssthresh to half of the minimum of the current
grzemich 0:d7bd7384a37c 1321 * cwnd and the advertised window */
grzemich 0:d7bd7384a37c 1322 if (pcb->cwnd > pcb->snd_wnd) {
grzemich 0:d7bd7384a37c 1323 pcb->ssthresh = pcb->snd_wnd / 2;
grzemich 0:d7bd7384a37c 1324 } else {
grzemich 0:d7bd7384a37c 1325 pcb->ssthresh = pcb->cwnd / 2;
grzemich 0:d7bd7384a37c 1326 }
grzemich 0:d7bd7384a37c 1327
grzemich 0:d7bd7384a37c 1328 /* The minimum value for ssthresh should be 2 MSS */
grzemich 0:d7bd7384a37c 1329 if (pcb->ssthresh < 2*pcb->mss) {
grzemich 0:d7bd7384a37c 1330 LWIP_DEBUGF(TCP_FR_DEBUG,
grzemich 0:d7bd7384a37c 1331 ("tcp_receive: The minimum value for ssthresh %"U16_F
grzemich 0:d7bd7384a37c 1332 " should be min 2 mss %"U16_F"...\n",
grzemich 0:d7bd7384a37c 1333 pcb->ssthresh, 2*pcb->mss));
grzemich 0:d7bd7384a37c 1334 pcb->ssthresh = 2*pcb->mss;
grzemich 0:d7bd7384a37c 1335 }
grzemich 0:d7bd7384a37c 1336
grzemich 0:d7bd7384a37c 1337 pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
grzemich 0:d7bd7384a37c 1338 pcb->flags |= TF_INFR;
grzemich 0:d7bd7384a37c 1339 }
grzemich 0:d7bd7384a37c 1340 }
grzemich 0:d7bd7384a37c 1341
grzemich 0:d7bd7384a37c 1342
grzemich 0:d7bd7384a37c 1343 /**
grzemich 0:d7bd7384a37c 1344 * Send keepalive packets to keep a connection active although
grzemich 0:d7bd7384a37c 1345 * no data is sent over it.
grzemich 0:d7bd7384a37c 1346 *
grzemich 0:d7bd7384a37c 1347 * Called by tcp_slowtmr()
grzemich 0:d7bd7384a37c 1348 *
grzemich 0:d7bd7384a37c 1349 * @param pcb the tcp_pcb for which to send a keepalive packet
grzemich 0:d7bd7384a37c 1350 */
grzemich 0:d7bd7384a37c 1351 void
grzemich 0:d7bd7384a37c 1352 tcp_keepalive(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1353 {
grzemich 0:d7bd7384a37c 1354 struct pbuf *p;
grzemich 0:d7bd7384a37c 1355 struct tcp_hdr *tcphdr;
grzemich 0:d7bd7384a37c 1356
grzemich 0:d7bd7384a37c 1357 LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
grzemich 0:d7bd7384a37c 1358 ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
grzemich 0:d7bd7384a37c 1359 ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
grzemich 0:d7bd7384a37c 1360
grzemich 0:d7bd7384a37c 1361 LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
grzemich 0:d7bd7384a37c 1362 tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
grzemich 0:d7bd7384a37c 1363
grzemich 0:d7bd7384a37c 1364 p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
grzemich 0:d7bd7384a37c 1365 if(p == NULL) {
grzemich 0:d7bd7384a37c 1366 LWIP_DEBUGF(TCP_DEBUG,
grzemich 0:d7bd7384a37c 1367 ("tcp_keepalive: could not allocate memory for pbuf\n"));
grzemich 0:d7bd7384a37c 1368 return;
grzemich 0:d7bd7384a37c 1369 }
grzemich 0:d7bd7384a37c 1370 tcphdr = (struct tcp_hdr *)p->payload;
grzemich 0:d7bd7384a37c 1371
grzemich 0:d7bd7384a37c 1372 #if CHECKSUM_GEN_TCP
grzemich 0:d7bd7384a37c 1373 tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
grzemich 0:d7bd7384a37c 1374 IP_PROTO_TCP, p->tot_len);
grzemich 0:d7bd7384a37c 1375 #endif
grzemich 0:d7bd7384a37c 1376 TCP_STATS_INC(tcp.xmit);
grzemich 0:d7bd7384a37c 1377
grzemich 0:d7bd7384a37c 1378 /* Send output to IP */
grzemich 0:d7bd7384a37c 1379 #if LWIP_NETIF_HWADDRHINT
grzemich 0:d7bd7384a37c 1380 ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
grzemich 0:d7bd7384a37c 1381 &(pcb->addr_hint));
grzemich 0:d7bd7384a37c 1382 #else /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1383 ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 1384 #endif /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1385
grzemich 0:d7bd7384a37c 1386 pbuf_free(p);
grzemich 0:d7bd7384a37c 1387
grzemich 0:d7bd7384a37c 1388 LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
grzemich 0:d7bd7384a37c 1389 pcb->snd_nxt - 1, pcb->rcv_nxt));
grzemich 0:d7bd7384a37c 1390 }
grzemich 0:d7bd7384a37c 1391
grzemich 0:d7bd7384a37c 1392
grzemich 0:d7bd7384a37c 1393 /**
grzemich 0:d7bd7384a37c 1394 * Send persist timer zero-window probes to keep a connection active
grzemich 0:d7bd7384a37c 1395 * when a window update is lost.
grzemich 0:d7bd7384a37c 1396 *
grzemich 0:d7bd7384a37c 1397 * Called by tcp_slowtmr()
grzemich 0:d7bd7384a37c 1398 *
grzemich 0:d7bd7384a37c 1399 * @param pcb the tcp_pcb for which to send a zero-window probe packet
grzemich 0:d7bd7384a37c 1400 */
grzemich 0:d7bd7384a37c 1401 void
grzemich 0:d7bd7384a37c 1402 tcp_zero_window_probe(struct tcp_pcb *pcb)
grzemich 0:d7bd7384a37c 1403 {
grzemich 0:d7bd7384a37c 1404 struct pbuf *p;
grzemich 0:d7bd7384a37c 1405 struct tcp_hdr *tcphdr;
grzemich 0:d7bd7384a37c 1406 struct tcp_seg *seg;
grzemich 0:d7bd7384a37c 1407 u16_t len;
grzemich 0:d7bd7384a37c 1408 u8_t is_fin;
grzemich 0:d7bd7384a37c 1409
grzemich 0:d7bd7384a37c 1410 LWIP_DEBUGF(TCP_DEBUG,
grzemich 0:d7bd7384a37c 1411 ("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
grzemich 0:d7bd7384a37c 1412 U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
grzemich 0:d7bd7384a37c 1413 ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
grzemich 0:d7bd7384a37c 1414 ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
grzemich 0:d7bd7384a37c 1415
grzemich 0:d7bd7384a37c 1416 LWIP_DEBUGF(TCP_DEBUG,
grzemich 0:d7bd7384a37c 1417 ("tcp_zero_window_probe: tcp_ticks %"U32_F
grzemich 0:d7bd7384a37c 1418 " pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
grzemich 0:d7bd7384a37c 1419 tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
grzemich 0:d7bd7384a37c 1420
grzemich 0:d7bd7384a37c 1421 seg = pcb->unacked;
grzemich 0:d7bd7384a37c 1422
grzemich 0:d7bd7384a37c 1423 if(seg == NULL) {
grzemich 0:d7bd7384a37c 1424 seg = pcb->unsent;
grzemich 0:d7bd7384a37c 1425 }
grzemich 0:d7bd7384a37c 1426 if(seg == NULL) {
grzemich 0:d7bd7384a37c 1427 return;
grzemich 0:d7bd7384a37c 1428 }
grzemich 0:d7bd7384a37c 1429
grzemich 0:d7bd7384a37c 1430 is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
grzemich 0:d7bd7384a37c 1431 /* we want to send one seqno: either FIN or data (no options) */
grzemich 0:d7bd7384a37c 1432 len = is_fin ? 0 : 1;
grzemich 0:d7bd7384a37c 1433
grzemich 0:d7bd7384a37c 1434 p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
grzemich 0:d7bd7384a37c 1435 if(p == NULL) {
grzemich 0:d7bd7384a37c 1436 LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
grzemich 0:d7bd7384a37c 1437 return;
grzemich 0:d7bd7384a37c 1438 }
grzemich 0:d7bd7384a37c 1439 tcphdr = (struct tcp_hdr *)p->payload;
grzemich 0:d7bd7384a37c 1440
grzemich 0:d7bd7384a37c 1441 if (is_fin) {
grzemich 0:d7bd7384a37c 1442 /* FIN segment, no data */
grzemich 0:d7bd7384a37c 1443 TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
grzemich 0:d7bd7384a37c 1444 } else {
grzemich 0:d7bd7384a37c 1445 /* Data segment, copy in one byte from the head of the unacked queue */
grzemich 0:d7bd7384a37c 1446 struct tcp_hdr *thdr = (struct tcp_hdr *)seg->p->payload;
grzemich 0:d7bd7384a37c 1447 char *d = ((char *)p->payload + TCP_HLEN);
grzemich 0:d7bd7384a37c 1448 pbuf_copy_partial(seg->p, d, 1, TCPH_HDRLEN(thdr) * 4);
grzemich 0:d7bd7384a37c 1449 }
grzemich 0:d7bd7384a37c 1450
grzemich 0:d7bd7384a37c 1451 #if CHECKSUM_GEN_TCP
grzemich 0:d7bd7384a37c 1452 tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
grzemich 0:d7bd7384a37c 1453 IP_PROTO_TCP, p->tot_len);
grzemich 0:d7bd7384a37c 1454 #endif
grzemich 0:d7bd7384a37c 1455 TCP_STATS_INC(tcp.xmit);
grzemich 0:d7bd7384a37c 1456
grzemich 0:d7bd7384a37c 1457 /* Send output to IP */
grzemich 0:d7bd7384a37c 1458 #if LWIP_NETIF_HWADDRHINT
grzemich 0:d7bd7384a37c 1459 ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
grzemich 0:d7bd7384a37c 1460 &(pcb->addr_hint));
grzemich 0:d7bd7384a37c 1461 #else /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1462 ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
grzemich 0:d7bd7384a37c 1463 #endif /* LWIP_NETIF_HWADDRHINT*/
grzemich 0:d7bd7384a37c 1464
grzemich 0:d7bd7384a37c 1465 pbuf_free(p);
grzemich 0:d7bd7384a37c 1466
grzemich 0:d7bd7384a37c 1467 LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
grzemich 0:d7bd7384a37c 1468 " ackno %"U32_F".\n",
grzemich 0:d7bd7384a37c 1469 pcb->snd_nxt - 1, pcb->rcv_nxt));
grzemich 0:d7bd7384a37c 1470 }
grzemich 0:d7bd7384a37c 1471 #endif /* LWIP_TCP */