[457] | 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 | * There are two distinct ways for TCP segments to get sent:
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| 8 | * - queued data: these are segments transferring data or segments containing
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| 9 | * SYN or FIN (which both count as one sequence number). They are created as
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| 10 | * struct @ref pbuf together with a struct tcp_seg and enqueue to the
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| 11 | * unsent list of the pcb. They are sent by tcp_output:
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| 12 | * - @ref tcp_write : creates data segments
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| 13 | * - @ref tcp_split_unsent_seg : splits a data segment
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| 14 | * - @ref tcp_enqueue_flags : creates SYN-only or FIN-only segments
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| 15 | * - @ref tcp_output / tcp_output_segment : finalize the tcp header
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| 16 | * (e.g. sequence numbers, options, checksum) and output to IP
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| 17 | * - the various tcp_rexmit functions shuffle around segments between the
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| 18 | * unsent an unacked lists to retransmit them
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| 19 | * - tcp_create_segment and tcp_pbuf_prealloc allocate pbuf and
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| 20 | * segment for these functions
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| 21 | * - direct send: these segments don't contain data but control the connection
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| 22 | * behaviour. They are created as pbuf only and sent directly without
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| 23 | * enqueueing them:
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| 24 | * - @ref tcp_send_empty_ack sends an ACK-only segment
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| 25 | * - @ref tcp_rst sends a RST segment
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| 26 | * - @ref tcp_keepalive sends a keepalive segment
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| 27 | * - @ref tcp_zero_window_probe sends a window probe segment
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| 28 | * - tcp_output_alloc_header allocates a header-only pbuf for these functions
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| 29 | */
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| 30 |
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| 31 | /*
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| 32 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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| 33 | * All rights reserved.
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| 34 | *
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| 35 | * Redistribution and use in source and binary forms, with or without modification,
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| 36 | * are permitted provided that the following conditions are met:
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| 37 | *
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| 38 | * 1. Redistributions of source code must retain the above copyright notice,
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| 39 | * this list of conditions and the following disclaimer.
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| 40 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 41 | * this list of conditions and the following disclaimer in the documentation
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| 42 | * and/or other materials provided with the distribution.
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| 43 | * 3. The name of the author may not be used to endorse or promote products
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| 44 | * derived from this software without specific prior written permission.
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| 45 | *
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| 46 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 47 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 48 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 49 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 50 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 51 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 52 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 53 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 54 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 55 | * OF SUCH DAMAGE.
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| 56 | *
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| 57 | * This file is part of the lwIP TCP/IP stack.
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| 58 | *
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| 59 | * Author: Adam Dunkels <adam@sics.se>
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| 60 | *
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| 61 | */
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| 62 |
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| 63 | #include "lwip/opt.h"
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| 64 |
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| 65 | #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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| 66 |
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| 67 | #include "lwip/priv/tcp_priv.h"
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| 68 | #include "lwip/def.h"
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| 69 | #include "lwip/mem.h"
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| 70 | #include "lwip/memp.h"
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| 71 | #include "lwip/ip_addr.h"
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| 72 | #include "lwip/netif.h"
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| 73 | #include "lwip/inet_chksum.h"
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| 74 | #include "lwip/stats.h"
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| 75 | #include "lwip/ip6.h"
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| 76 | #include "lwip/ip6_addr.h"
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| 77 | #if LWIP_TCP_TIMESTAMPS
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| 78 | #include "lwip/sys.h"
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| 79 | #endif
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| 80 |
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| 81 | #include <string.h>
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| 82 |
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| 83 | #ifdef LWIP_HOOK_FILENAME
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| 84 | #include LWIP_HOOK_FILENAME
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| 85 | #endif
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| 86 |
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| 87 | /* Allow to add custom TCP header options by defining this hook */
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| 88 | #ifdef LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH
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| 89 | #define LWIP_TCP_OPT_LENGTH_SEGMENT(flags, pcb) LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH(pcb, LWIP_TCP_OPT_LENGTH(flags))
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| 90 | #else
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| 91 | #define LWIP_TCP_OPT_LENGTH_SEGMENT(flags, pcb) LWIP_TCP_OPT_LENGTH(flags)
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| 92 | #endif
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| 93 |
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| 94 | /* Define some copy-macros for checksum-on-copy so that the code looks
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| 95 | nicer by preventing too many ifdef's. */
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| 96 | #if TCP_CHECKSUM_ON_COPY
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| 97 | #define TCP_DATA_COPY(dst, src, len, seg) do { \
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| 98 | tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
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| 99 | len, &seg->chksum, &seg->chksum_swapped); \
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| 100 | seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
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| 101 | #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
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| 102 | tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
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| 103 | #else /* TCP_CHECKSUM_ON_COPY*/
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| 104 | #define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
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| 105 | #define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
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| 106 | #endif /* TCP_CHECKSUM_ON_COPY*/
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| 107 |
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| 108 | /** Define this to 1 for an extra check that the output checksum is valid
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| 109 | * (usefule when the checksum is generated by the application, not the stack) */
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| 110 | #ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
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| 111 | #define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
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| 112 | #endif
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| 113 | /* Allow to override the failure of sanity check from warning to e.g. hard failure */
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| 114 | #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
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| 115 | #ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL
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| 116 | #define TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL(msg) LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING, msg)
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| 117 | #endif
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| 118 | #endif
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| 119 |
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| 120 | #if TCP_OVERSIZE
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| 121 | /** The size of segment pbufs created when TCP_OVERSIZE is enabled */
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| 122 | #ifndef TCP_OVERSIZE_CALC_LENGTH
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| 123 | #define TCP_OVERSIZE_CALC_LENGTH(length) ((length) + TCP_OVERSIZE)
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| 124 | #endif
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| 125 | #endif
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| 126 |
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| 127 | /* Forward declarations.*/
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| 128 | static err_t tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb, struct netif *netif);
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| 129 |
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| 130 | /* tcp_route: common code that returns a fixed bound netif or calls ip_route */
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| 131 | static struct netif *
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| 132 | tcp_route(const struct tcp_pcb *pcb, const ip_addr_t *src, const ip_addr_t *dst)
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| 133 | {
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| 134 | LWIP_UNUSED_ARG(src); /* in case IPv4-only and source-based routing is disabled */
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| 135 |
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| 136 | if ((pcb != NULL) && (pcb->netif_idx != NETIF_NO_INDEX)) {
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| 137 | return netif_get_by_index(pcb->netif_idx);
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| 138 | } else {
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| 139 | return ip_route(src, dst);
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| 140 | }
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| 141 | }
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| 142 |
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| 143 | /**
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| 144 | * Create a TCP segment with prefilled header.
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| 145 | *
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| 146 | * Called by @ref tcp_write, @ref tcp_enqueue_flags and @ref tcp_split_unsent_seg
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| 147 | *
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| 148 | * @param pcb Protocol control block for the TCP connection.
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| 149 | * @param p pbuf that is used to hold the TCP header.
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| 150 | * @param hdrflags TCP flags for header.
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| 151 | * @param seqno TCP sequence number of this packet
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| 152 | * @param optflags options to include in TCP header
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| 153 | * @return a new tcp_seg pointing to p, or NULL.
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| 154 | * The TCP header is filled in except ackno and wnd.
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| 155 | * p is freed on failure.
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| 156 | */
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| 157 | static struct tcp_seg *
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| 158 | tcp_create_segment(const struct tcp_pcb *pcb, struct pbuf *p, u8_t hdrflags, u32_t seqno, u8_t optflags)
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| 159 | {
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| 160 | struct tcp_seg *seg;
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| 161 | u8_t optlen;
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| 162 |
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| 163 | LWIP_ASSERT("tcp_create_segment: invalid pcb", pcb != NULL);
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| 164 | LWIP_ASSERT("tcp_create_segment: invalid pbuf", p != NULL);
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| 165 |
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| 166 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
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| 167 |
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| 168 | if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
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| 169 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_create_segment: no memory.\n"));
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| 170 | pbuf_free(p);
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| 171 | return NULL;
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| 172 | }
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| 173 | seg->flags = optflags;
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| 174 | seg->next = NULL;
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| 175 | seg->p = p;
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| 176 | LWIP_ASSERT("p->tot_len >= optlen", p->tot_len >= optlen);
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| 177 | seg->len = p->tot_len - optlen;
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| 178 | #if TCP_OVERSIZE_DBGCHECK
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| 179 | seg->oversize_left = 0;
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| 180 | #endif /* TCP_OVERSIZE_DBGCHECK */
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| 181 | #if TCP_CHECKSUM_ON_COPY
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| 182 | seg->chksum = 0;
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| 183 | seg->chksum_swapped = 0;
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| 184 | /* check optflags */
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| 185 | LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
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| 186 | (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
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| 187 | #endif /* TCP_CHECKSUM_ON_COPY */
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| 188 |
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| 189 | /* build TCP header */
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| 190 | if (pbuf_add_header(p, TCP_HLEN)) {
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| 191 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
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| 192 | TCP_STATS_INC(tcp.err);
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| 193 | tcp_seg_free(seg);
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| 194 | return NULL;
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| 195 | }
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| 196 | seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
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| 197 | seg->tcphdr->src = lwip_htons(pcb->local_port);
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| 198 | seg->tcphdr->dest = lwip_htons(pcb->remote_port);
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| 199 | seg->tcphdr->seqno = lwip_htonl(seqno);
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| 200 | /* ackno is set in tcp_output */
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| 201 | TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), hdrflags);
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| 202 | /* wnd and chksum are set in tcp_output */
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| 203 | seg->tcphdr->urgp = 0;
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| 204 | return seg;
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| 205 | }
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| 206 |
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| 207 | /**
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| 208 | * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
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| 209 | *
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| 210 | * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
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| 211 | * there may be extra bytes available at the end.
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| 212 | *
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| 213 | * Called by @ref tcp_write
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| 214 | *
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| 215 | * @param layer flag to define header size.
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| 216 | * @param length size of the pbuf's payload.
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| 217 | * @param max_length maximum usable size of payload+oversize.
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| 218 | * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
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| 219 | * @param pcb The TCP connection that will enqueue the pbuf.
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| 220 | * @param apiflags API flags given to tcp_write.
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| 221 | * @param first_seg true when this pbuf will be used in the first enqueued segment.
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| 222 | */
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| 223 | #if TCP_OVERSIZE
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| 224 | static struct pbuf *
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| 225 | tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
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| 226 | u16_t *oversize, const struct tcp_pcb *pcb, u8_t apiflags,
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| 227 | u8_t first_seg)
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| 228 | {
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| 229 | struct pbuf *p;
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| 230 | u16_t alloc = length;
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| 231 |
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| 232 | LWIP_ASSERT("tcp_pbuf_prealloc: invalid oversize", oversize != NULL);
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| 233 | LWIP_ASSERT("tcp_pbuf_prealloc: invalid pcb", pcb != NULL);
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| 234 |
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| 235 | #if LWIP_NETIF_TX_SINGLE_PBUF
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| 236 | LWIP_UNUSED_ARG(max_length);
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| 237 | LWIP_UNUSED_ARG(pcb);
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| 238 | LWIP_UNUSED_ARG(apiflags);
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| 239 | LWIP_UNUSED_ARG(first_seg);
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| 240 | alloc = max_length;
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| 241 | #else /* LWIP_NETIF_TX_SINGLE_PBUF */
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| 242 | if (length < max_length) {
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| 243 | /* Should we allocate an oversized pbuf, or just the minimum
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| 244 | * length required? If tcp_write is going to be called again
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| 245 | * before this segment is transmitted, we want the oversized
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| 246 | * buffer. If the segment will be transmitted immediately, we can
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| 247 | * save memory by allocating only length. We use a simple
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| 248 | * heuristic based on the following information:
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| 249 | *
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| 250 | * Did the user set TCP_WRITE_FLAG_MORE?
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| 251 | *
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| 252 | * Will the Nagle algorithm defer transmission of this segment?
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| 253 | */
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| 254 | if ((apiflags & TCP_WRITE_FLAG_MORE) ||
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| 255 | (!(pcb->flags & TF_NODELAY) &&
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| 256 | (!first_seg ||
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| 257 | pcb->unsent != NULL ||
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| 258 | pcb->unacked != NULL))) {
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| 259 | alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(TCP_OVERSIZE_CALC_LENGTH(length)));
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| 260 | }
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| 261 | }
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| 262 | #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
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| 263 | p = pbuf_alloc(layer, alloc, PBUF_RAM);
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| 264 | if (p == NULL) {
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| 265 | return NULL;
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| 266 | }
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| 267 | LWIP_ASSERT("need unchained pbuf", p->next == NULL);
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| 268 | *oversize = p->len - length;
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| 269 | /* trim p->len to the currently used size */
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| 270 | p->len = p->tot_len = length;
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| 271 | return p;
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| 272 | }
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| 273 | #else /* TCP_OVERSIZE */
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| 274 | #define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
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| 275 | #endif /* TCP_OVERSIZE */
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| 276 |
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| 277 | #if TCP_CHECKSUM_ON_COPY
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| 278 | /** Add a checksum of newly added data to the segment.
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| 279 | *
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| 280 | * Called by tcp_write and tcp_split_unsent_seg.
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| 281 | */
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| 282 | static void
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| 283 | tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
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| 284 | u8_t *seg_chksum_swapped)
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| 285 | {
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| 286 | u32_t helper;
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| 287 | /* add chksum to old chksum and fold to u16_t */
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| 288 | helper = chksum + *seg_chksum;
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| 289 | chksum = FOLD_U32T(helper);
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| 290 | if ((len & 1) != 0) {
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| 291 | *seg_chksum_swapped = 1 - *seg_chksum_swapped;
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| 292 | chksum = SWAP_BYTES_IN_WORD(chksum);
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| 293 | }
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| 294 | *seg_chksum = chksum;
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| 295 | }
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| 296 | #endif /* TCP_CHECKSUM_ON_COPY */
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| 297 |
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| 298 | /** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
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| 299 | *
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| 300 | * @param pcb the tcp pcb to check for
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| 301 | * @param len length of data to send (checked agains snd_buf)
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| 302 | * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
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| 303 | */
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| 304 | static err_t
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| 305 | tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
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| 306 | {
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| 307 | LWIP_ASSERT("tcp_write_checks: invalid pcb", pcb != NULL);
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| 308 |
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| 309 | /* connection is in invalid state for data transmission? */
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| 310 | if ((pcb->state != ESTABLISHED) &&
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| 311 | (pcb->state != CLOSE_WAIT) &&
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| 312 | (pcb->state != SYN_SENT) &&
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| 313 | (pcb->state != SYN_RCVD)) {
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| 314 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
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| 315 | return ERR_CONN;
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| 316 | } else if (len == 0) {
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| 317 | return ERR_OK;
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| 318 | }
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| 319 |
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| 320 | /* fail on too much data */
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| 321 | if (len > pcb->snd_buf) {
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| 322 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"TCPWNDSIZE_F")\n",
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| 323 | len, pcb->snd_buf));
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| 324 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
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| 325 | return ERR_MEM;
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| 326 | }
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| 327 |
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| 328 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"TCPWNDSIZE_F"\n", (tcpwnd_size_t)pcb->snd_queuelen));
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| 329 |
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| 330 | /* If total number of pbufs on the unsent/unacked queues exceeds the
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| 331 | * configured maximum, return an error */
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| 332 | /* check for configured max queuelen and possible overflow */
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| 333 | if (pcb->snd_queuelen >= LWIP_MIN(TCP_SND_QUEUELEN, (TCP_SNDQUEUELEN_OVERFLOW + 1))) {
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| 334 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
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| 335 | pcb->snd_queuelen, (u16_t)TCP_SND_QUEUELEN));
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| 336 | TCP_STATS_INC(tcp.memerr);
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| 337 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
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| 338 | return ERR_MEM;
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| 339 | }
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| 340 | if (pcb->snd_queuelen != 0) {
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| 341 | LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
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| 342 | pcb->unacked != NULL || pcb->unsent != NULL);
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| 343 | } else {
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| 344 | LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
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| 345 | pcb->unacked == NULL && pcb->unsent == NULL);
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| 346 | }
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| 347 | return ERR_OK;
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| 348 | }
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| 349 |
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| 350 | /**
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| 351 | * @ingroup tcp_raw
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| 352 | * Write data for sending (but does not send it immediately).
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| 353 | *
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| 354 | * It waits in the expectation of more data being sent soon (as
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| 355 | * it can send them more efficiently by combining them together).
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| 356 | * To prompt the system to send data now, call tcp_output() after
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| 357 | * calling tcp_write().
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| 358 | *
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| 359 | * This function enqueues the data pointed to by the argument dataptr. The length of
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| 360 | * the data is passed as the len parameter. The apiflags can be one or more of:
|
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| 361 | * - TCP_WRITE_FLAG_COPY: indicates whether the new memory should be allocated
|
---|
| 362 | * for the data to be copied into. If this flag is not given, no new memory
|
---|
| 363 | * should be allocated and the data should only be referenced by pointer. This
|
---|
| 364 | * also means that the memory behind dataptr must not change until the data is
|
---|
| 365 | * ACKed by the remote host
|
---|
| 366 | * - TCP_WRITE_FLAG_MORE: indicates that more data follows. If this is omitted,
|
---|
| 367 | * the PSH flag is set in the last segment created by this call to tcp_write.
|
---|
| 368 | * If this flag is given, the PSH flag is not set.
|
---|
| 369 | *
|
---|
| 370 | * The tcp_write() function will fail and return ERR_MEM if the length
|
---|
| 371 | * of the data exceeds the current send buffer size or if the length of
|
---|
| 372 | * the queue of outgoing segment is larger than the upper limit defined
|
---|
| 373 | * in lwipopts.h. The number of bytes available in the output queue can
|
---|
| 374 | * be retrieved with the tcp_sndbuf() function.
|
---|
| 375 | *
|
---|
| 376 | * The proper way to use this function is to call the function with at
|
---|
| 377 | * most tcp_sndbuf() bytes of data. If the function returns ERR_MEM,
|
---|
| 378 | * the application should wait until some of the currently enqueued
|
---|
| 379 | * data has been successfully received by the other host and try again.
|
---|
| 380 | *
|
---|
| 381 | * @param pcb Protocol control block for the TCP connection to enqueue data for.
|
---|
| 382 | * @param arg Pointer to the data to be enqueued for sending.
|
---|
| 383 | * @param len Data length in bytes
|
---|
| 384 | * @param apiflags combination of following flags :
|
---|
| 385 | * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
|
---|
| 386 | * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will not be set on last segment sent,
|
---|
| 387 | * @return ERR_OK if enqueued, another err_t on error
|
---|
| 388 | */
|
---|
| 389 | err_t
|
---|
| 390 | tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
|
---|
| 391 | {
|
---|
| 392 | struct pbuf *concat_p = NULL;
|
---|
| 393 | struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
|
---|
| 394 | u16_t pos = 0; /* position in 'arg' data */
|
---|
| 395 | u16_t queuelen;
|
---|
| 396 | u8_t optlen;
|
---|
| 397 | u8_t optflags = 0;
|
---|
| 398 | #if TCP_OVERSIZE
|
---|
| 399 | u16_t oversize = 0;
|
---|
| 400 | u16_t oversize_used = 0;
|
---|
| 401 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 402 | u16_t oversize_add = 0;
|
---|
| 403 | #endif /* TCP_OVERSIZE_DBGCHECK*/
|
---|
| 404 | #endif /* TCP_OVERSIZE */
|
---|
| 405 | u16_t extendlen = 0;
|
---|
| 406 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 407 | u16_t concat_chksum = 0;
|
---|
| 408 | u8_t concat_chksum_swapped = 0;
|
---|
| 409 | u16_t concat_chksummed = 0;
|
---|
| 410 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 411 | err_t err;
|
---|
| 412 | u16_t mss_local;
|
---|
| 413 |
|
---|
| 414 | LWIP_ERROR("tcp_write: invalid pcb", pcb != NULL, return ERR_ARG);
|
---|
| 415 |
|
---|
| 416 | /* don't allocate segments bigger than half the maximum window we ever received */
|
---|
| 417 | mss_local = LWIP_MIN(pcb->mss, TCPWND_MIN16(pcb->snd_wnd_max / 2));
|
---|
| 418 | mss_local = mss_local ? mss_local : pcb->mss;
|
---|
| 419 |
|
---|
| 420 | LWIP_ASSERT_CORE_LOCKED();
|
---|
| 421 |
|
---|
| 422 | #if LWIP_NETIF_TX_SINGLE_PBUF
|
---|
| 423 | /* Always copy to try to create single pbufs for TX */
|
---|
| 424 | apiflags |= TCP_WRITE_FLAG_COPY;
|
---|
| 425 | #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
|
---|
| 426 |
|
---|
| 427 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
|
---|
| 428 | (void *)pcb, arg, len, (u16_t)apiflags));
|
---|
| 429 | LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
|
---|
| 430 | arg != NULL, return ERR_ARG;);
|
---|
| 431 |
|
---|
| 432 | err = tcp_write_checks(pcb, len);
|
---|
| 433 | if (err != ERR_OK) {
|
---|
| 434 | return err;
|
---|
| 435 | }
|
---|
| 436 | queuelen = pcb->snd_queuelen;
|
---|
| 437 |
|
---|
| 438 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 439 | if ((pcb->flags & TF_TIMESTAMP)) {
|
---|
| 440 | /* Make sure the timestamp option is only included in data segments if we
|
---|
| 441 | agreed about it with the remote host. */
|
---|
| 442 | optflags = TF_SEG_OPTS_TS;
|
---|
| 443 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(TF_SEG_OPTS_TS, pcb);
|
---|
| 444 | /* ensure that segments can hold at least one data byte... */
|
---|
| 445 | mss_local = LWIP_MAX(mss_local, LWIP_TCP_OPT_LEN_TS + 1);
|
---|
| 446 | } else
|
---|
| 447 | #endif /* LWIP_TCP_TIMESTAMPS */
|
---|
| 448 | {
|
---|
| 449 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
---|
| 450 | }
|
---|
| 451 |
|
---|
| 452 |
|
---|
| 453 | /*
|
---|
| 454 | * TCP segmentation is done in three phases with increasing complexity:
|
---|
| 455 | *
|
---|
| 456 | * 1. Copy data directly into an oversized pbuf.
|
---|
| 457 | * 2. Chain a new pbuf to the end of pcb->unsent.
|
---|
| 458 | * 3. Create new segments.
|
---|
| 459 | *
|
---|
| 460 | * We may run out of memory at any point. In that case we must
|
---|
| 461 | * return ERR_MEM and not change anything in pcb. Therefore, all
|
---|
| 462 | * changes are recorded in local variables and committed at the end
|
---|
| 463 | * of the function. Some pcb fields are maintained in local copies:
|
---|
| 464 | *
|
---|
| 465 | * queuelen = pcb->snd_queuelen
|
---|
| 466 | * oversize = pcb->unsent_oversize
|
---|
| 467 | *
|
---|
| 468 | * These variables are set consistently by the phases:
|
---|
| 469 | *
|
---|
| 470 | * seg points to the last segment tampered with.
|
---|
| 471 | *
|
---|
| 472 | * pos records progress as data is segmented.
|
---|
| 473 | */
|
---|
| 474 |
|
---|
| 475 | /* Find the tail of the unsent queue. */
|
---|
| 476 | if (pcb->unsent != NULL) {
|
---|
| 477 | u16_t space;
|
---|
| 478 | u16_t unsent_optlen;
|
---|
| 479 |
|
---|
| 480 | /* @todo: this could be sped up by keeping last_unsent in the pcb */
|
---|
| 481 | for (last_unsent = pcb->unsent; last_unsent->next != NULL;
|
---|
| 482 | last_unsent = last_unsent->next);
|
---|
| 483 |
|
---|
| 484 | /* Usable space at the end of the last unsent segment */
|
---|
| 485 | unsent_optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(last_unsent->flags, pcb);
|
---|
| 486 | LWIP_ASSERT("mss_local is too small", mss_local >= last_unsent->len + unsent_optlen);
|
---|
| 487 | space = mss_local - (last_unsent->len + unsent_optlen);
|
---|
| 488 |
|
---|
| 489 | /*
|
---|
| 490 | * Phase 1: Copy data directly into an oversized pbuf.
|
---|
| 491 | *
|
---|
| 492 | * The number of bytes copied is recorded in the oversize_used
|
---|
| 493 | * variable. The actual copying is done at the bottom of the
|
---|
| 494 | * function.
|
---|
| 495 | */
|
---|
| 496 | #if TCP_OVERSIZE
|
---|
| 497 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 498 | /* check that pcb->unsent_oversize matches last_unsent->oversize_left */
|
---|
| 499 | LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
|
---|
| 500 | pcb->unsent_oversize == last_unsent->oversize_left);
|
---|
| 501 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 502 | oversize = pcb->unsent_oversize;
|
---|
| 503 | if (oversize > 0) {
|
---|
| 504 | LWIP_ASSERT("inconsistent oversize vs. space", oversize <= space);
|
---|
| 505 | seg = last_unsent;
|
---|
| 506 | oversize_used = LWIP_MIN(space, LWIP_MIN(oversize, len));
|
---|
| 507 | pos += oversize_used;
|
---|
| 508 | oversize -= oversize_used;
|
---|
| 509 | space -= oversize_used;
|
---|
| 510 | }
|
---|
| 511 | /* now we are either finished or oversize is zero */
|
---|
| 512 | LWIP_ASSERT("inconsistent oversize vs. len", (oversize == 0) || (pos == len));
|
---|
| 513 | #endif /* TCP_OVERSIZE */
|
---|
| 514 |
|
---|
| 515 | #if !LWIP_NETIF_TX_SINGLE_PBUF
|
---|
| 516 | /*
|
---|
| 517 | * Phase 2: Chain a new pbuf to the end of pcb->unsent.
|
---|
| 518 | *
|
---|
| 519 | * As an exception when NOT copying the data, if the given data buffer
|
---|
| 520 | * directly follows the last unsent data buffer in memory, extend the last
|
---|
| 521 | * ROM pbuf reference to the buffer, thus saving a ROM pbuf allocation.
|
---|
| 522 | *
|
---|
| 523 | * We don't extend segments containing SYN/FIN flags or options
|
---|
| 524 | * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
|
---|
| 525 | * the end.
|
---|
| 526 | *
|
---|
| 527 | * This phase is skipped for LWIP_NETIF_TX_SINGLE_PBUF as we could only execute
|
---|
| 528 | * it after rexmit puts a segment from unacked to unsent and at this point,
|
---|
| 529 | * oversize info is lost.
|
---|
| 530 | */
|
---|
| 531 | if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
|
---|
| 532 | u16_t seglen = LWIP_MIN(space, len - pos);
|
---|
| 533 | seg = last_unsent;
|
---|
| 534 |
|
---|
| 535 | /* Create a pbuf with a copy or reference to seglen bytes. We
|
---|
| 536 | * can use PBUF_RAW here since the data appears in the middle of
|
---|
| 537 | * a segment. A header will never be prepended. */
|
---|
| 538 | if (apiflags & TCP_WRITE_FLAG_COPY) {
|
---|
| 539 | /* Data is copied */
|
---|
| 540 | if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
|
---|
| 541 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
---|
| 542 | ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
|
---|
| 543 | seglen));
|
---|
| 544 | goto memerr;
|
---|
| 545 | }
|
---|
| 546 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 547 | oversize_add = oversize;
|
---|
| 548 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 549 | TCP_DATA_COPY2(concat_p->payload, (const u8_t *)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
|
---|
| 550 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 551 | concat_chksummed += seglen;
|
---|
| 552 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 553 | queuelen += pbuf_clen(concat_p);
|
---|
| 554 | } else {
|
---|
| 555 | /* Data is not copied */
|
---|
| 556 | /* If the last unsent pbuf is of type PBUF_ROM, try to extend it. */
|
---|
| 557 | struct pbuf *p;
|
---|
| 558 | for (p = last_unsent->p; p->next != NULL; p = p->next);
|
---|
| 559 | if (((p->type_internal & (PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_FLAG_DATA_VOLATILE)) == 0) &&
|
---|
| 560 | (const u8_t *)p->payload + p->len == (const u8_t *)arg) {
|
---|
| 561 | LWIP_ASSERT("tcp_write: ROM pbufs cannot be oversized", pos == 0);
|
---|
| 562 | extendlen = seglen;
|
---|
| 563 | } else {
|
---|
| 564 | if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
|
---|
| 565 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
---|
| 566 | ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
---|
| 567 | goto memerr;
|
---|
| 568 | }
|
---|
| 569 | /* reference the non-volatile payload data */
|
---|
| 570 | ((struct pbuf_rom *)concat_p)->payload = (const u8_t *)arg + pos;
|
---|
| 571 | queuelen += pbuf_clen(concat_p);
|
---|
| 572 | }
|
---|
| 573 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 574 | /* calculate the checksum of nocopy-data */
|
---|
| 575 | tcp_seg_add_chksum(~inet_chksum((const u8_t *)arg + pos, seglen), seglen,
|
---|
| 576 | &concat_chksum, &concat_chksum_swapped);
|
---|
| 577 | concat_chksummed += seglen;
|
---|
| 578 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 579 | }
|
---|
| 580 |
|
---|
| 581 | pos += seglen;
|
---|
| 582 | }
|
---|
| 583 | #endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
|
---|
| 584 | } else {
|
---|
| 585 | #if TCP_OVERSIZE
|
---|
| 586 | LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
|
---|
| 587 | pcb->unsent_oversize == 0);
|
---|
| 588 | #endif /* TCP_OVERSIZE */
|
---|
| 589 | }
|
---|
| 590 |
|
---|
| 591 | /*
|
---|
| 592 | * Phase 3: Create new segments.
|
---|
| 593 | *
|
---|
| 594 | * The new segments are chained together in the local 'queue'
|
---|
| 595 | * variable, ready to be appended to pcb->unsent.
|
---|
| 596 | */
|
---|
| 597 | while (pos < len) {
|
---|
| 598 | struct pbuf *p;
|
---|
| 599 | u16_t left = len - pos;
|
---|
| 600 | u16_t max_len = mss_local - optlen;
|
---|
| 601 | u16_t seglen = LWIP_MIN(left, max_len);
|
---|
| 602 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 603 | u16_t chksum = 0;
|
---|
| 604 | u8_t chksum_swapped = 0;
|
---|
| 605 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 606 |
|
---|
| 607 | if (apiflags & TCP_WRITE_FLAG_COPY) {
|
---|
| 608 | /* If copy is set, memory should be allocated and data copied
|
---|
| 609 | * into pbuf */
|
---|
| 610 | if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
|
---|
| 611 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
|
---|
| 612 | goto memerr;
|
---|
| 613 | }
|
---|
| 614 | LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
|
---|
| 615 | (p->len >= seglen));
|
---|
| 616 | TCP_DATA_COPY2((char *)p->payload + optlen, (const u8_t *)arg + pos, seglen, &chksum, &chksum_swapped);
|
---|
| 617 | } else {
|
---|
| 618 | /* Copy is not set: First allocate a pbuf for holding the data.
|
---|
| 619 | * Since the referenced data is available at least until it is
|
---|
| 620 | * sent out on the link (as it has to be ACKed by the remote
|
---|
| 621 | * party) we can safely use PBUF_ROM instead of PBUF_REF here.
|
---|
| 622 | */
|
---|
| 623 | struct pbuf *p2;
|
---|
| 624 | #if TCP_OVERSIZE
|
---|
| 625 | LWIP_ASSERT("oversize == 0", oversize == 0);
|
---|
| 626 | #endif /* TCP_OVERSIZE */
|
---|
| 627 | if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
|
---|
| 628 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
---|
| 629 | goto memerr;
|
---|
| 630 | }
|
---|
| 631 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 632 | /* calculate the checksum of nocopy-data */
|
---|
| 633 | chksum = ~inet_chksum((const u8_t *)arg + pos, seglen);
|
---|
| 634 | if (seglen & 1) {
|
---|
| 635 | chksum_swapped = 1;
|
---|
| 636 | chksum = SWAP_BYTES_IN_WORD(chksum);
|
---|
| 637 | }
|
---|
| 638 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 639 | /* reference the non-volatile payload data */
|
---|
| 640 | ((struct pbuf_rom *)p2)->payload = (const u8_t *)arg + pos;
|
---|
| 641 |
|
---|
| 642 | /* Second, allocate a pbuf for the headers. */
|
---|
| 643 | if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
---|
| 644 | /* If allocation fails, we have to deallocate the data pbuf as
|
---|
| 645 | * well. */
|
---|
| 646 | pbuf_free(p2);
|
---|
| 647 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: could not allocate memory for header pbuf\n"));
|
---|
| 648 | goto memerr;
|
---|
| 649 | }
|
---|
| 650 | /* Concatenate the headers and data pbufs together. */
|
---|
| 651 | pbuf_cat(p/*header*/, p2/*data*/);
|
---|
| 652 | }
|
---|
| 653 |
|
---|
| 654 | queuelen += pbuf_clen(p);
|
---|
| 655 |
|
---|
| 656 | /* Now that there are more segments queued, we check again if the
|
---|
| 657 | * length of the queue exceeds the configured maximum or
|
---|
| 658 | * overflows. */
|
---|
| 659 | if (queuelen > LWIP_MIN(TCP_SND_QUEUELEN, TCP_SNDQUEUELEN_OVERFLOW)) {
|
---|
| 660 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: queue too long %"U16_F" (%d)\n",
|
---|
| 661 | queuelen, (int)TCP_SND_QUEUELEN));
|
---|
| 662 | pbuf_free(p);
|
---|
| 663 | goto memerr;
|
---|
| 664 | }
|
---|
| 665 |
|
---|
| 666 | if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
|
---|
| 667 | goto memerr;
|
---|
| 668 | }
|
---|
| 669 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 670 | seg->oversize_left = oversize;
|
---|
| 671 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 672 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 673 | seg->chksum = chksum;
|
---|
| 674 | seg->chksum_swapped = chksum_swapped;
|
---|
| 675 | seg->flags |= TF_SEG_DATA_CHECKSUMMED;
|
---|
| 676 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 677 |
|
---|
| 678 | /* first segment of to-be-queued data? */
|
---|
| 679 | if (queue == NULL) {
|
---|
| 680 | queue = seg;
|
---|
| 681 | } else {
|
---|
| 682 | /* Attach the segment to the end of the queued segments */
|
---|
| 683 | LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
|
---|
| 684 | prev_seg->next = seg;
|
---|
| 685 | }
|
---|
| 686 | /* remember last segment of to-be-queued data for next iteration */
|
---|
| 687 | prev_seg = seg;
|
---|
| 688 |
|
---|
| 689 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
|
---|
| 690 | lwip_ntohl(seg->tcphdr->seqno),
|
---|
| 691 | lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
|
---|
| 692 |
|
---|
| 693 | pos += seglen;
|
---|
| 694 | }
|
---|
| 695 |
|
---|
| 696 | /*
|
---|
| 697 | * All three segmentation phases were successful. We can commit the
|
---|
| 698 | * transaction.
|
---|
| 699 | */
|
---|
| 700 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 701 | if ((last_unsent != NULL) && (oversize_add != 0)) {
|
---|
| 702 | last_unsent->oversize_left += oversize_add;
|
---|
| 703 | }
|
---|
| 704 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 705 |
|
---|
| 706 | /*
|
---|
| 707 | * Phase 1: If data has been added to the preallocated tail of
|
---|
| 708 | * last_unsent, we update the length fields of the pbuf chain.
|
---|
| 709 | */
|
---|
| 710 | #if TCP_OVERSIZE
|
---|
| 711 | if (oversize_used > 0) {
|
---|
| 712 | struct pbuf *p;
|
---|
| 713 | /* Bump tot_len of whole chain, len of tail */
|
---|
| 714 | for (p = last_unsent->p; p; p = p->next) {
|
---|
| 715 | p->tot_len += oversize_used;
|
---|
| 716 | if (p->next == NULL) {
|
---|
| 717 | TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
|
---|
| 718 | p->len += oversize_used;
|
---|
| 719 | }
|
---|
| 720 | }
|
---|
| 721 | last_unsent->len += oversize_used;
|
---|
| 722 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 723 | LWIP_ASSERT("last_unsent->oversize_left >= oversize_used",
|
---|
| 724 | last_unsent->oversize_left >= oversize_used);
|
---|
| 725 | last_unsent->oversize_left -= oversize_used;
|
---|
| 726 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 727 | }
|
---|
| 728 | pcb->unsent_oversize = oversize;
|
---|
| 729 | #endif /* TCP_OVERSIZE */
|
---|
| 730 |
|
---|
| 731 | /*
|
---|
| 732 | * Phase 2: concat_p can be concatenated onto last_unsent->p, unless we
|
---|
| 733 | * determined that the last ROM pbuf can be extended to include the new data.
|
---|
| 734 | */
|
---|
| 735 | if (concat_p != NULL) {
|
---|
| 736 | LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
|
---|
| 737 | (last_unsent != NULL));
|
---|
| 738 | pbuf_cat(last_unsent->p, concat_p);
|
---|
| 739 | last_unsent->len += concat_p->tot_len;
|
---|
| 740 | } else if (extendlen > 0) {
|
---|
| 741 | struct pbuf *p;
|
---|
| 742 | LWIP_ASSERT("tcp_write: extension of reference requires reference",
|
---|
| 743 | last_unsent != NULL && last_unsent->p != NULL);
|
---|
| 744 | for (p = last_unsent->p; p->next != NULL; p = p->next) {
|
---|
| 745 | p->tot_len += extendlen;
|
---|
| 746 | }
|
---|
| 747 | p->tot_len += extendlen;
|
---|
| 748 | p->len += extendlen;
|
---|
| 749 | last_unsent->len += extendlen;
|
---|
| 750 | }
|
---|
| 751 |
|
---|
| 752 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 753 | if (concat_chksummed) {
|
---|
| 754 | LWIP_ASSERT("tcp_write: concat checksum needs concatenated data",
|
---|
| 755 | concat_p != NULL || extendlen > 0);
|
---|
| 756 | /*if concat checksumm swapped - swap it back */
|
---|
| 757 | if (concat_chksum_swapped) {
|
---|
| 758 | concat_chksum = SWAP_BYTES_IN_WORD(concat_chksum);
|
---|
| 759 | }
|
---|
| 760 | tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
|
---|
| 761 | &last_unsent->chksum_swapped);
|
---|
| 762 | last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
|
---|
| 763 | }
|
---|
| 764 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 765 |
|
---|
| 766 | /*
|
---|
| 767 | * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
|
---|
| 768 | * is harmless
|
---|
| 769 | */
|
---|
| 770 | if (last_unsent == NULL) {
|
---|
| 771 | pcb->unsent = queue;
|
---|
| 772 | } else {
|
---|
| 773 | last_unsent->next = queue;
|
---|
| 774 | }
|
---|
| 775 |
|
---|
| 776 | /*
|
---|
| 777 | * Finally update the pcb state.
|
---|
| 778 | */
|
---|
| 779 | pcb->snd_lbb += len;
|
---|
| 780 | pcb->snd_buf -= len;
|
---|
| 781 | pcb->snd_queuelen = queuelen;
|
---|
| 782 |
|
---|
| 783 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
|
---|
| 784 | pcb->snd_queuelen));
|
---|
| 785 | if (pcb->snd_queuelen != 0) {
|
---|
| 786 | LWIP_ASSERT("tcp_write: valid queue length",
|
---|
| 787 | pcb->unacked != NULL || pcb->unsent != NULL);
|
---|
| 788 | }
|
---|
| 789 |
|
---|
| 790 | /* Set the PSH flag in the last segment that we enqueued. */
|
---|
| 791 | if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE) == 0)) {
|
---|
| 792 | TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
|
---|
| 793 | }
|
---|
| 794 |
|
---|
| 795 | return ERR_OK;
|
---|
| 796 | memerr:
|
---|
| 797 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
---|
| 798 | TCP_STATS_INC(tcp.memerr);
|
---|
| 799 |
|
---|
| 800 | if (concat_p != NULL) {
|
---|
| 801 | pbuf_free(concat_p);
|
---|
| 802 | }
|
---|
| 803 | if (queue != NULL) {
|
---|
| 804 | tcp_segs_free(queue);
|
---|
| 805 | }
|
---|
| 806 | if (pcb->snd_queuelen != 0) {
|
---|
| 807 | LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
|
---|
| 808 | pcb->unsent != NULL);
|
---|
| 809 | }
|
---|
| 810 | LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
|
---|
| 811 | return ERR_MEM;
|
---|
| 812 | }
|
---|
| 813 |
|
---|
| 814 | /**
|
---|
| 815 | * Split segment on the head of the unsent queue. If return is not
|
---|
| 816 | * ERR_OK, existing head remains intact
|
---|
| 817 | *
|
---|
| 818 | * The split is accomplished by creating a new TCP segment and pbuf
|
---|
| 819 | * which holds the remainder payload after the split. The original
|
---|
| 820 | * pbuf is trimmed to new length. This allows splitting of read-only
|
---|
| 821 | * pbufs
|
---|
| 822 | *
|
---|
| 823 | * @param pcb the tcp_pcb for which to split the unsent head
|
---|
| 824 | * @param split the amount of payload to remain in the head
|
---|
| 825 | */
|
---|
| 826 | err_t
|
---|
| 827 | tcp_split_unsent_seg(struct tcp_pcb *pcb, u16_t split)
|
---|
| 828 | {
|
---|
| 829 | struct tcp_seg *seg = NULL, *useg = NULL;
|
---|
| 830 | struct pbuf *p = NULL;
|
---|
| 831 | u8_t optlen;
|
---|
| 832 | u8_t optflags;
|
---|
| 833 | u8_t split_flags;
|
---|
| 834 | u8_t remainder_flags;
|
---|
| 835 | u16_t remainder;
|
---|
| 836 | u16_t offset;
|
---|
| 837 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 838 | u16_t chksum = 0;
|
---|
| 839 | u8_t chksum_swapped = 0;
|
---|
| 840 | struct pbuf *q;
|
---|
| 841 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 842 |
|
---|
| 843 | LWIP_ASSERT("tcp_split_unsent_seg: invalid pcb", pcb != NULL);
|
---|
| 844 |
|
---|
| 845 | useg = pcb->unsent;
|
---|
| 846 | if (useg == NULL) {
|
---|
| 847 | return ERR_MEM;
|
---|
| 848 | }
|
---|
| 849 |
|
---|
| 850 | if (split == 0) {
|
---|
| 851 | LWIP_ASSERT("Can't split segment into length 0", 0);
|
---|
| 852 | return ERR_VAL;
|
---|
| 853 | }
|
---|
| 854 |
|
---|
| 855 | if (useg->len <= split) {
|
---|
| 856 | return ERR_OK;
|
---|
| 857 | }
|
---|
| 858 |
|
---|
| 859 | LWIP_ASSERT("split <= mss", split <= pcb->mss);
|
---|
| 860 | LWIP_ASSERT("useg->len > 0", useg->len > 0);
|
---|
| 861 |
|
---|
| 862 | /* We should check that we don't exceed TCP_SND_QUEUELEN but we need
|
---|
| 863 | * to split this packet so we may actually exceed the max value by
|
---|
| 864 | * one!
|
---|
| 865 | */
|
---|
| 866 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: split_unsent_seg: %u\n", (unsigned int)pcb->snd_queuelen));
|
---|
| 867 |
|
---|
| 868 | optflags = useg->flags;
|
---|
| 869 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 870 | /* Remove since checksum is not stored until after tcp_create_segment() */
|
---|
| 871 | optflags &= ~TF_SEG_DATA_CHECKSUMMED;
|
---|
| 872 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 873 | optlen = LWIP_TCP_OPT_LENGTH(optflags);
|
---|
| 874 | remainder = useg->len - split;
|
---|
| 875 |
|
---|
| 876 | /* Create new pbuf for the remainder of the split */
|
---|
| 877 | p = pbuf_alloc(PBUF_TRANSPORT, remainder + optlen, PBUF_RAM);
|
---|
| 878 | if (p == NULL) {
|
---|
| 879 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
---|
| 880 | ("tcp_split_unsent_seg: could not allocate memory for pbuf remainder %u\n", remainder));
|
---|
| 881 | goto memerr;
|
---|
| 882 | }
|
---|
| 883 |
|
---|
| 884 | /* Offset into the original pbuf is past TCP/IP headers, options, and split amount */
|
---|
| 885 | offset = useg->p->tot_len - useg->len + split;
|
---|
| 886 | /* Copy remainder into new pbuf, headers and options will not be filled out */
|
---|
| 887 | if (pbuf_copy_partial(useg->p, (u8_t *)p->payload + optlen, remainder, offset ) != remainder) {
|
---|
| 888 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
---|
| 889 | ("tcp_split_unsent_seg: could not copy pbuf remainder %u\n", remainder));
|
---|
| 890 | goto memerr;
|
---|
| 891 | }
|
---|
| 892 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 893 | /* calculate the checksum on remainder data */
|
---|
| 894 | tcp_seg_add_chksum(~inet_chksum((const u8_t *)p->payload + optlen, remainder), remainder,
|
---|
| 895 | &chksum, &chksum_swapped);
|
---|
| 896 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 897 |
|
---|
| 898 | /* Options are created when calling tcp_output() */
|
---|
| 899 |
|
---|
| 900 | /* Migrate flags from original segment */
|
---|
| 901 | split_flags = TCPH_FLAGS(useg->tcphdr);
|
---|
| 902 | remainder_flags = 0; /* ACK added in tcp_output() */
|
---|
| 903 |
|
---|
| 904 | if (split_flags & TCP_PSH) {
|
---|
| 905 | split_flags &= ~TCP_PSH;
|
---|
| 906 | remainder_flags |= TCP_PSH;
|
---|
| 907 | }
|
---|
| 908 | if (split_flags & TCP_FIN) {
|
---|
| 909 | split_flags &= ~TCP_FIN;
|
---|
| 910 | remainder_flags |= TCP_FIN;
|
---|
| 911 | }
|
---|
| 912 | /* SYN should be left on split, RST should not be present with data */
|
---|
| 913 |
|
---|
| 914 | seg = tcp_create_segment(pcb, p, remainder_flags, lwip_ntohl(useg->tcphdr->seqno) + split, optflags);
|
---|
| 915 | if (seg == NULL) {
|
---|
| 916 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
---|
| 917 | ("tcp_split_unsent_seg: could not create new TCP segment\n"));
|
---|
| 918 | goto memerr;
|
---|
| 919 | }
|
---|
| 920 |
|
---|
| 921 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 922 | seg->chksum = chksum;
|
---|
| 923 | seg->chksum_swapped = chksum_swapped;
|
---|
| 924 | seg->flags |= TF_SEG_DATA_CHECKSUMMED;
|
---|
| 925 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 926 |
|
---|
| 927 | /* Remove this segment from the queue since trimming it may free pbufs */
|
---|
| 928 | pcb->snd_queuelen -= pbuf_clen(useg->p);
|
---|
| 929 |
|
---|
| 930 | /* Trim the original pbuf into our split size. At this point our remainder segment must be setup
|
---|
| 931 | successfully because we are modifying the original segment */
|
---|
| 932 | pbuf_realloc(useg->p, useg->p->tot_len - remainder);
|
---|
| 933 | useg->len -= remainder;
|
---|
| 934 | TCPH_SET_FLAG(useg->tcphdr, split_flags);
|
---|
| 935 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 936 | /* By trimming, realloc may have actually shrunk the pbuf, so clear oversize_left */
|
---|
| 937 | useg->oversize_left = 0;
|
---|
| 938 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 939 |
|
---|
| 940 | /* Add back to the queue with new trimmed pbuf */
|
---|
| 941 | pcb->snd_queuelen += pbuf_clen(useg->p);
|
---|
| 942 |
|
---|
| 943 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 944 | /* The checksum on the split segment is now incorrect. We need to re-run it over the split */
|
---|
| 945 | useg->chksum = 0;
|
---|
| 946 | useg->chksum_swapped = 0;
|
---|
| 947 | q = useg->p;
|
---|
| 948 | offset = q->tot_len - useg->len; /* Offset due to exposed headers */
|
---|
| 949 |
|
---|
| 950 | /* Advance to the pbuf where the offset ends */
|
---|
| 951 | while (q != NULL && offset > q->len) {
|
---|
| 952 | offset -= q->len;
|
---|
| 953 | q = q->next;
|
---|
| 954 | }
|
---|
| 955 | LWIP_ASSERT("Found start of payload pbuf", q != NULL);
|
---|
| 956 | /* Checksum the first payload pbuf accounting for offset, then other pbufs are all payload */
|
---|
| 957 | for (; q != NULL; offset = 0, q = q->next) {
|
---|
| 958 | tcp_seg_add_chksum(~inet_chksum((const u8_t *)q->payload + offset, q->len - offset), q->len - offset,
|
---|
| 959 | &useg->chksum, &useg->chksum_swapped);
|
---|
| 960 | }
|
---|
| 961 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 962 |
|
---|
| 963 | /* Update number of segments on the queues. Note that length now may
|
---|
| 964 | * exceed TCP_SND_QUEUELEN! We don't have to touch pcb->snd_buf
|
---|
| 965 | * because the total amount of data is constant when packet is split */
|
---|
| 966 | pcb->snd_queuelen += pbuf_clen(seg->p);
|
---|
| 967 |
|
---|
| 968 | /* Finally insert remainder into queue after split (which stays head) */
|
---|
| 969 | seg->next = useg->next;
|
---|
| 970 | useg->next = seg;
|
---|
| 971 |
|
---|
| 972 | #if TCP_OVERSIZE
|
---|
| 973 | /* If remainder is last segment on the unsent, ensure we clear the oversize amount
|
---|
| 974 | * because the remainder is always sized to the exact remaining amount */
|
---|
| 975 | if (seg->next == NULL) {
|
---|
| 976 | pcb->unsent_oversize = 0;
|
---|
| 977 | }
|
---|
| 978 | #endif /* TCP_OVERSIZE */
|
---|
| 979 |
|
---|
| 980 | return ERR_OK;
|
---|
| 981 | memerr:
|
---|
| 982 | TCP_STATS_INC(tcp.memerr);
|
---|
| 983 |
|
---|
| 984 | LWIP_ASSERT("seg == NULL", seg == NULL);
|
---|
| 985 | if (p != NULL) {
|
---|
| 986 | pbuf_free(p);
|
---|
| 987 | }
|
---|
| 988 |
|
---|
| 989 | return ERR_MEM;
|
---|
| 990 | }
|
---|
| 991 |
|
---|
| 992 | /**
|
---|
| 993 | * Called by tcp_close() to send a segment including FIN flag but not data.
|
---|
| 994 | * This FIN may be added to an existing segment or a new, otherwise empty
|
---|
| 995 | * segment is enqueued.
|
---|
| 996 | *
|
---|
| 997 | * @param pcb the tcp_pcb over which to send a segment
|
---|
| 998 | * @return ERR_OK if sent, another err_t otherwise
|
---|
| 999 | */
|
---|
| 1000 | err_t
|
---|
| 1001 | tcp_send_fin(struct tcp_pcb *pcb)
|
---|
| 1002 | {
|
---|
| 1003 | LWIP_ASSERT("tcp_send_fin: invalid pcb", pcb != NULL);
|
---|
| 1004 |
|
---|
| 1005 | /* first, try to add the fin to the last unsent segment */
|
---|
| 1006 | if (pcb->unsent != NULL) {
|
---|
| 1007 | struct tcp_seg *last_unsent;
|
---|
| 1008 | for (last_unsent = pcb->unsent; last_unsent->next != NULL;
|
---|
| 1009 | last_unsent = last_unsent->next);
|
---|
| 1010 |
|
---|
| 1011 | if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
|
---|
| 1012 | /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
|
---|
| 1013 | TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
|
---|
| 1014 | tcp_set_flags(pcb, TF_FIN);
|
---|
| 1015 | return ERR_OK;
|
---|
| 1016 | }
|
---|
| 1017 | }
|
---|
| 1018 | /* no data, no length, flags, copy=1, no optdata */
|
---|
| 1019 | return tcp_enqueue_flags(pcb, TCP_FIN);
|
---|
| 1020 | }
|
---|
| 1021 |
|
---|
| 1022 | /**
|
---|
| 1023 | * Enqueue SYN or FIN for transmission.
|
---|
| 1024 | *
|
---|
| 1025 | * Called by @ref tcp_connect, tcp_listen_input, and @ref tcp_close
|
---|
| 1026 | * (via @ref tcp_send_fin)
|
---|
| 1027 | *
|
---|
| 1028 | * @param pcb Protocol control block for the TCP connection.
|
---|
| 1029 | * @param flags TCP header flags to set in the outgoing segment.
|
---|
| 1030 | */
|
---|
| 1031 | err_t
|
---|
| 1032 | tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
|
---|
| 1033 | {
|
---|
| 1034 | struct pbuf *p;
|
---|
| 1035 | struct tcp_seg *seg;
|
---|
| 1036 | u8_t optflags = 0;
|
---|
| 1037 | u8_t optlen = 0;
|
---|
| 1038 |
|
---|
| 1039 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
|
---|
| 1040 |
|
---|
| 1041 | LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
|
---|
| 1042 | (flags & (TCP_SYN | TCP_FIN)) != 0);
|
---|
| 1043 | LWIP_ASSERT("tcp_enqueue_flags: invalid pcb", pcb != NULL);
|
---|
| 1044 |
|
---|
| 1045 | /* No need to check pcb->snd_queuelen if only SYN or FIN are allowed! */
|
---|
| 1046 |
|
---|
| 1047 | /* Get options for this segment. This is a special case since this is the
|
---|
| 1048 | only place where a SYN can be sent. */
|
---|
| 1049 | if (flags & TCP_SYN) {
|
---|
| 1050 | optflags = TF_SEG_OPTS_MSS;
|
---|
| 1051 | #if LWIP_WND_SCALE
|
---|
| 1052 | if ((pcb->state != SYN_RCVD) || (pcb->flags & TF_WND_SCALE)) {
|
---|
| 1053 | /* In a <SYN,ACK> (sent in state SYN_RCVD), the window scale option may only
|
---|
| 1054 | be sent if we received a window scale option from the remote host. */
|
---|
| 1055 | optflags |= TF_SEG_OPTS_WND_SCALE;
|
---|
| 1056 | }
|
---|
| 1057 | #endif /* LWIP_WND_SCALE */
|
---|
| 1058 | #if LWIP_TCP_SACK_OUT
|
---|
| 1059 | if ((pcb->state != SYN_RCVD) || (pcb->flags & TF_SACK)) {
|
---|
| 1060 | /* In a <SYN,ACK> (sent in state SYN_RCVD), the SACK_PERM option may only
|
---|
| 1061 | be sent if we received a SACK_PERM option from the remote host. */
|
---|
| 1062 | optflags |= TF_SEG_OPTS_SACK_PERM;
|
---|
| 1063 | }
|
---|
| 1064 | #endif /* LWIP_TCP_SACK_OUT */
|
---|
| 1065 | }
|
---|
| 1066 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 1067 | if ((pcb->flags & TF_TIMESTAMP) || ((flags & TCP_SYN) && (pcb->state != SYN_RCVD))) {
|
---|
| 1068 | /* Make sure the timestamp option is only included in data segments if we
|
---|
| 1069 | agreed about it with the remote host (and in active open SYN segments). */
|
---|
| 1070 | optflags |= TF_SEG_OPTS_TS;
|
---|
| 1071 | }
|
---|
| 1072 | #endif /* LWIP_TCP_TIMESTAMPS */
|
---|
| 1073 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
|
---|
| 1074 |
|
---|
| 1075 | /* Allocate pbuf with room for TCP header + options */
|
---|
| 1076 | if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
---|
| 1077 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
---|
| 1078 | TCP_STATS_INC(tcp.memerr);
|
---|
| 1079 | return ERR_MEM;
|
---|
| 1080 | }
|
---|
| 1081 | LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
|
---|
| 1082 | (p->len >= optlen));
|
---|
| 1083 |
|
---|
| 1084 | /* Allocate memory for tcp_seg, and fill in fields. */
|
---|
| 1085 | if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
|
---|
| 1086 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
---|
| 1087 | TCP_STATS_INC(tcp.memerr);
|
---|
| 1088 | return ERR_MEM;
|
---|
| 1089 | }
|
---|
| 1090 | LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % LWIP_MIN(MEM_ALIGNMENT, 4)) == 0);
|
---|
| 1091 | LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
|
---|
| 1092 |
|
---|
| 1093 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
|
---|
| 1094 | ("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
|
---|
| 1095 | lwip_ntohl(seg->tcphdr->seqno),
|
---|
| 1096 | lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
|
---|
| 1097 | (u16_t)flags));
|
---|
| 1098 |
|
---|
| 1099 | /* Now append seg to pcb->unsent queue */
|
---|
| 1100 | if (pcb->unsent == NULL) {
|
---|
| 1101 | pcb->unsent = seg;
|
---|
| 1102 | } else {
|
---|
| 1103 | struct tcp_seg *useg;
|
---|
| 1104 | for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
|
---|
| 1105 | useg->next = seg;
|
---|
| 1106 | }
|
---|
| 1107 | #if TCP_OVERSIZE
|
---|
| 1108 | /* The new unsent tail has no space */
|
---|
| 1109 | pcb->unsent_oversize = 0;
|
---|
| 1110 | #endif /* TCP_OVERSIZE */
|
---|
| 1111 |
|
---|
| 1112 | /* SYN and FIN bump the sequence number */
|
---|
| 1113 | if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
|
---|
| 1114 | pcb->snd_lbb++;
|
---|
| 1115 | /* optlen does not influence snd_buf */
|
---|
| 1116 | }
|
---|
| 1117 | if (flags & TCP_FIN) {
|
---|
| 1118 | tcp_set_flags(pcb, TF_FIN);
|
---|
| 1119 | }
|
---|
| 1120 |
|
---|
| 1121 | /* update number of segments on the queues */
|
---|
| 1122 | pcb->snd_queuelen += pbuf_clen(seg->p);
|
---|
| 1123 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
|
---|
| 1124 | if (pcb->snd_queuelen != 0) {
|
---|
| 1125 | LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
|
---|
| 1126 | pcb->unacked != NULL || pcb->unsent != NULL);
|
---|
| 1127 | }
|
---|
| 1128 |
|
---|
| 1129 | return ERR_OK;
|
---|
| 1130 | }
|
---|
| 1131 |
|
---|
| 1132 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 1133 | /* Build a timestamp option (12 bytes long) at the specified options pointer)
|
---|
| 1134 | *
|
---|
| 1135 | * @param pcb tcp_pcb
|
---|
| 1136 | * @param opts option pointer where to store the timestamp option
|
---|
| 1137 | */
|
---|
| 1138 | static void
|
---|
| 1139 | tcp_build_timestamp_option(const struct tcp_pcb *pcb, u32_t *opts)
|
---|
| 1140 | {
|
---|
| 1141 | LWIP_ASSERT("tcp_build_timestamp_option: invalid pcb", pcb != NULL);
|
---|
| 1142 |
|
---|
| 1143 | /* Pad with two NOP options to make everything nicely aligned */
|
---|
| 1144 | opts[0] = PP_HTONL(0x0101080A);
|
---|
| 1145 | opts[1] = lwip_htonl(sys_now());
|
---|
| 1146 | opts[2] = lwip_htonl(pcb->ts_recent);
|
---|
| 1147 | }
|
---|
| 1148 | #endif
|
---|
| 1149 |
|
---|
| 1150 | #if LWIP_TCP_SACK_OUT
|
---|
| 1151 | /**
|
---|
| 1152 | * Calculates the number of SACK entries that should be generated.
|
---|
| 1153 | * It takes into account whether TF_SACK flag is set,
|
---|
| 1154 | * the number of SACK entries in tcp_pcb that are valid,
|
---|
| 1155 | * as well as the available options size.
|
---|
| 1156 | *
|
---|
| 1157 | * @param pcb tcp_pcb
|
---|
| 1158 | * @param optlen the length of other TCP options (in bytes)
|
---|
| 1159 | * @return the number of SACK ranges that can be used
|
---|
| 1160 | */
|
---|
| 1161 | static u8_t
|
---|
| 1162 | tcp_get_num_sacks(const struct tcp_pcb *pcb, u8_t optlen)
|
---|
| 1163 | {
|
---|
| 1164 | u8_t num_sacks = 0;
|
---|
| 1165 |
|
---|
| 1166 | LWIP_ASSERT("tcp_get_num_sacks: invalid pcb", pcb != NULL);
|
---|
| 1167 |
|
---|
| 1168 | if (pcb->flags & TF_SACK) {
|
---|
| 1169 | u8_t i;
|
---|
| 1170 |
|
---|
| 1171 | /* The first SACK takes up 12 bytes (it includes SACK header and two NOP options),
|
---|
| 1172 | each additional one - 8 bytes. */
|
---|
| 1173 | optlen += 12;
|
---|
| 1174 |
|
---|
| 1175 | /* Max options size = 40, number of SACK array entries = LWIP_TCP_MAX_SACK_NUM */
|
---|
| 1176 | for (i = 0; (i < LWIP_TCP_MAX_SACK_NUM) && (optlen <= TCP_MAX_OPTION_BYTES) &&
|
---|
| 1177 | LWIP_TCP_SACK_VALID(pcb, i); ++i) {
|
---|
| 1178 | ++num_sacks;
|
---|
| 1179 | optlen += 8;
|
---|
| 1180 | }
|
---|
| 1181 | }
|
---|
| 1182 |
|
---|
| 1183 | return num_sacks;
|
---|
| 1184 | }
|
---|
| 1185 |
|
---|
| 1186 | /** Build a SACK option (12 or more bytes long) at the specified options pointer)
|
---|
| 1187 | *
|
---|
| 1188 | * @param pcb tcp_pcb
|
---|
| 1189 | * @param opts option pointer where to store the SACK option
|
---|
| 1190 | * @param num_sacks the number of SACKs to store
|
---|
| 1191 | */
|
---|
| 1192 | static void
|
---|
| 1193 | tcp_build_sack_option(const struct tcp_pcb *pcb, u32_t *opts, u8_t num_sacks)
|
---|
| 1194 | {
|
---|
| 1195 | u8_t i;
|
---|
| 1196 |
|
---|
| 1197 | LWIP_ASSERT("tcp_build_sack_option: invalid pcb", pcb != NULL);
|
---|
| 1198 | LWIP_ASSERT("tcp_build_sack_option: invalid opts", opts != NULL);
|
---|
| 1199 |
|
---|
| 1200 | /* Pad with two NOP options to make everything nicely aligned.
|
---|
| 1201 | We add the length (of just the SACK option, not the NOPs in front of it),
|
---|
| 1202 | which is 2B of header, plus 8B for each SACK. */
|
---|
| 1203 | *(opts++) = PP_HTONL(0x01010500 + 2 + num_sacks * 8);
|
---|
| 1204 |
|
---|
| 1205 | for (i = 0; i < num_sacks; ++i) {
|
---|
| 1206 | *(opts++) = lwip_htonl(pcb->rcv_sacks[i].left);
|
---|
| 1207 | *(opts++) = lwip_htonl(pcb->rcv_sacks[i].right);
|
---|
| 1208 | }
|
---|
| 1209 | }
|
---|
| 1210 |
|
---|
| 1211 | #endif
|
---|
| 1212 |
|
---|
| 1213 | #if LWIP_WND_SCALE
|
---|
| 1214 | /** Build a window scale option (3 bytes long) at the specified options pointer)
|
---|
| 1215 | *
|
---|
| 1216 | * @param opts option pointer where to store the window scale option
|
---|
| 1217 | */
|
---|
| 1218 | static void
|
---|
| 1219 | tcp_build_wnd_scale_option(u32_t *opts)
|
---|
| 1220 | {
|
---|
| 1221 | LWIP_ASSERT("tcp_build_wnd_scale_option: invalid opts", opts != NULL);
|
---|
| 1222 |
|
---|
| 1223 | /* Pad with one NOP option to make everything nicely aligned */
|
---|
| 1224 | opts[0] = PP_HTONL(0x01030300 | TCP_RCV_SCALE);
|
---|
| 1225 | }
|
---|
| 1226 | #endif
|
---|
| 1227 |
|
---|
| 1228 | /**
|
---|
| 1229 | * @ingroup tcp_raw
|
---|
| 1230 | * Find out what we can send and send it
|
---|
| 1231 | *
|
---|
| 1232 | * @param pcb Protocol control block for the TCP connection to send data
|
---|
| 1233 | * @return ERR_OK if data has been sent or nothing to send
|
---|
| 1234 | * another err_t on error
|
---|
| 1235 | */
|
---|
| 1236 | err_t
|
---|
| 1237 | tcp_output(struct tcp_pcb *pcb)
|
---|
| 1238 | {
|
---|
| 1239 | struct tcp_seg *seg, *useg;
|
---|
| 1240 | u32_t wnd, snd_nxt;
|
---|
| 1241 | err_t err;
|
---|
| 1242 | struct netif *netif;
|
---|
| 1243 | #if TCP_CWND_DEBUG
|
---|
| 1244 | s16_t i = 0;
|
---|
| 1245 | #endif /* TCP_CWND_DEBUG */
|
---|
| 1246 |
|
---|
| 1247 | LWIP_ASSERT_CORE_LOCKED();
|
---|
| 1248 |
|
---|
| 1249 | LWIP_ASSERT("tcp_output: invalid pcb", pcb != NULL);
|
---|
| 1250 | /* pcb->state LISTEN not allowed here */
|
---|
| 1251 | LWIP_ASSERT("don't call tcp_output for listen-pcbs",
|
---|
| 1252 | pcb->state != LISTEN);
|
---|
| 1253 |
|
---|
| 1254 | /* First, check if we are invoked by the TCP input processing
|
---|
| 1255 | code. If so, we do not output anything. Instead, we rely on the
|
---|
| 1256 | input processing code to call us when input processing is done
|
---|
| 1257 | with. */
|
---|
| 1258 | if (tcp_input_pcb == pcb) {
|
---|
| 1259 | return ERR_OK;
|
---|
| 1260 | }
|
---|
| 1261 |
|
---|
| 1262 | wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
|
---|
| 1263 |
|
---|
| 1264 | seg = pcb->unsent;
|
---|
| 1265 |
|
---|
| 1266 | if (seg == NULL) {
|
---|
| 1267 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
|
---|
| 1268 | (void *)pcb->unsent));
|
---|
| 1269 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"TCPWNDSIZE_F
|
---|
| 1270 | ", cwnd %"TCPWNDSIZE_F", wnd %"U32_F
|
---|
| 1271 | ", seg == NULL, ack %"U32_F"\n",
|
---|
| 1272 | pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
|
---|
| 1273 |
|
---|
| 1274 | /* If the TF_ACK_NOW flag is set and the ->unsent queue is empty, construct
|
---|
| 1275 | * an empty ACK segment and send it. */
|
---|
| 1276 | if (pcb->flags & TF_ACK_NOW) {
|
---|
| 1277 | return tcp_send_empty_ack(pcb);
|
---|
| 1278 | }
|
---|
| 1279 | /* nothing to send: shortcut out of here */
|
---|
| 1280 | goto output_done;
|
---|
| 1281 | } else {
|
---|
| 1282 | LWIP_DEBUGF(TCP_CWND_DEBUG,
|
---|
| 1283 | ("tcp_output: snd_wnd %"TCPWNDSIZE_F", cwnd %"TCPWNDSIZE_F", wnd %"U32_F
|
---|
| 1284 | ", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
|
---|
| 1285 | pcb->snd_wnd, pcb->cwnd, wnd,
|
---|
| 1286 | lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
|
---|
| 1287 | lwip_ntohl(seg->tcphdr->seqno), pcb->lastack));
|
---|
| 1288 | }
|
---|
| 1289 |
|
---|
| 1290 | netif = tcp_route(pcb, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 1291 | if (netif == NULL) {
|
---|
| 1292 | return ERR_RTE;
|
---|
| 1293 | }
|
---|
| 1294 |
|
---|
| 1295 | /* If we don't have a local IP address, we get one from netif */
|
---|
| 1296 | if (ip_addr_isany(&pcb->local_ip)) {
|
---|
| 1297 | const ip_addr_t *local_ip = ip_netif_get_local_ip(netif, &pcb->remote_ip);
|
---|
| 1298 | if (local_ip == NULL) {
|
---|
| 1299 | return ERR_RTE;
|
---|
| 1300 | }
|
---|
| 1301 | ip_addr_copy(pcb->local_ip, *local_ip);
|
---|
| 1302 | }
|
---|
| 1303 |
|
---|
| 1304 | /* Handle the current segment not fitting within the window */
|
---|
| 1305 | if (lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd) {
|
---|
| 1306 | /* We need to start the persistent timer when the next unsent segment does not fit
|
---|
| 1307 | * within the remaining (could be 0) send window and RTO timer is not running (we
|
---|
| 1308 | * have no in-flight data). If window is still too small after persist timer fires,
|
---|
| 1309 | * then we split the segment. We don't consider the congestion window since a cwnd
|
---|
| 1310 | * smaller than 1 SMSS implies in-flight data
|
---|
| 1311 | */
|
---|
| 1312 | if (wnd == pcb->snd_wnd && pcb->unacked == NULL && pcb->persist_backoff == 0) {
|
---|
| 1313 | pcb->persist_cnt = 0;
|
---|
| 1314 | pcb->persist_backoff = 1;
|
---|
| 1315 | pcb->persist_probe = 0;
|
---|
| 1316 | }
|
---|
| 1317 | /* We need an ACK, but can't send data now, so send an empty ACK */
|
---|
| 1318 | if (pcb->flags & TF_ACK_NOW) {
|
---|
| 1319 | return tcp_send_empty_ack(pcb);
|
---|
| 1320 | }
|
---|
| 1321 | goto output_done;
|
---|
| 1322 | }
|
---|
| 1323 | /* Stop persist timer, above conditions are not active */
|
---|
| 1324 | pcb->persist_backoff = 0;
|
---|
| 1325 |
|
---|
| 1326 | /* useg should point to last segment on unacked queue */
|
---|
| 1327 | useg = pcb->unacked;
|
---|
| 1328 | if (useg != NULL) {
|
---|
| 1329 | for (; useg->next != NULL; useg = useg->next);
|
---|
| 1330 | }
|
---|
| 1331 | /* data available and window allows it to be sent? */
|
---|
| 1332 | while (seg != NULL &&
|
---|
| 1333 | lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
|
---|
| 1334 | LWIP_ASSERT("RST not expected here!",
|
---|
| 1335 | (TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
|
---|
| 1336 | /* Stop sending if the nagle algorithm would prevent it
|
---|
| 1337 | * Don't stop:
|
---|
| 1338 | * - if tcp_write had a memory error before (prevent delayed ACK timeout) or
|
---|
| 1339 | * - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
|
---|
| 1340 | * either seg->next != NULL or pcb->unacked == NULL;
|
---|
| 1341 | * RST is no sent using tcp_write/tcp_output.
|
---|
| 1342 | */
|
---|
| 1343 | if ((tcp_do_output_nagle(pcb) == 0) &&
|
---|
| 1344 | ((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)) {
|
---|
| 1345 | break;
|
---|
| 1346 | }
|
---|
| 1347 | #if TCP_CWND_DEBUG
|
---|
| 1348 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"TCPWNDSIZE_F", cwnd %"TCPWNDSIZE_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\n",
|
---|
| 1349 | pcb->snd_wnd, pcb->cwnd, wnd,
|
---|
| 1350 | lwip_ntohl(seg->tcphdr->seqno) + seg->len -
|
---|
| 1351 | pcb->lastack,
|
---|
| 1352 | lwip_ntohl(seg->tcphdr->seqno), pcb->lastack, i));
|
---|
| 1353 | ++i;
|
---|
| 1354 | #endif /* TCP_CWND_DEBUG */
|
---|
| 1355 |
|
---|
| 1356 | if (pcb->state != SYN_SENT) {
|
---|
| 1357 | TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
|
---|
| 1358 | }
|
---|
| 1359 |
|
---|
| 1360 | err = tcp_output_segment(seg, pcb, netif);
|
---|
| 1361 | if (err != ERR_OK) {
|
---|
| 1362 | /* segment could not be sent, for whatever reason */
|
---|
| 1363 | tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
---|
| 1364 | return err;
|
---|
| 1365 | }
|
---|
| 1366 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 1367 | seg->oversize_left = 0;
|
---|
| 1368 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 1369 | pcb->unsent = seg->next;
|
---|
| 1370 | if (pcb->state != SYN_SENT) {
|
---|
| 1371 | tcp_clear_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 1372 | }
|
---|
| 1373 | snd_nxt = lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
|
---|
| 1374 | if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
---|
| 1375 | pcb->snd_nxt = snd_nxt;
|
---|
| 1376 | }
|
---|
| 1377 | /* put segment on unacknowledged list if length > 0 */
|
---|
| 1378 | if (TCP_TCPLEN(seg) > 0) {
|
---|
| 1379 | seg->next = NULL;
|
---|
| 1380 | /* unacked list is empty? */
|
---|
| 1381 | if (pcb->unacked == NULL) {
|
---|
| 1382 | pcb->unacked = seg;
|
---|
| 1383 | useg = seg;
|
---|
| 1384 | /* unacked list is not empty? */
|
---|
| 1385 | } else {
|
---|
| 1386 | /* In the case of fast retransmit, the packet should not go to the tail
|
---|
| 1387 | * of the unacked queue, but rather somewhere before it. We need to check for
|
---|
| 1388 | * this case. -STJ Jul 27, 2004 */
|
---|
| 1389 | if (TCP_SEQ_LT(lwip_ntohl(seg->tcphdr->seqno), lwip_ntohl(useg->tcphdr->seqno))) {
|
---|
| 1390 | /* add segment to before tail of unacked list, keeping the list sorted */
|
---|
| 1391 | struct tcp_seg **cur_seg = &(pcb->unacked);
|
---|
| 1392 | while (*cur_seg &&
|
---|
| 1393 | TCP_SEQ_LT(lwip_ntohl((*cur_seg)->tcphdr->seqno), lwip_ntohl(seg->tcphdr->seqno))) {
|
---|
| 1394 | cur_seg = &((*cur_seg)->next );
|
---|
| 1395 | }
|
---|
| 1396 | seg->next = (*cur_seg);
|
---|
| 1397 | (*cur_seg) = seg;
|
---|
| 1398 | } else {
|
---|
| 1399 | /* add segment to tail of unacked list */
|
---|
| 1400 | useg->next = seg;
|
---|
| 1401 | useg = useg->next;
|
---|
| 1402 | }
|
---|
| 1403 | }
|
---|
| 1404 | /* do not queue empty segments on the unacked list */
|
---|
| 1405 | } else {
|
---|
| 1406 | tcp_seg_free(seg);
|
---|
| 1407 | }
|
---|
| 1408 | seg = pcb->unsent;
|
---|
| 1409 | }
|
---|
| 1410 | #if TCP_OVERSIZE
|
---|
| 1411 | if (pcb->unsent == NULL) {
|
---|
| 1412 | /* last unsent has been removed, reset unsent_oversize */
|
---|
| 1413 | pcb->unsent_oversize = 0;
|
---|
| 1414 | }
|
---|
| 1415 | #endif /* TCP_OVERSIZE */
|
---|
| 1416 |
|
---|
| 1417 | output_done:
|
---|
| 1418 | tcp_clear_flags(pcb, TF_NAGLEMEMERR);
|
---|
| 1419 | return ERR_OK;
|
---|
| 1420 | }
|
---|
| 1421 |
|
---|
| 1422 | /** Check if a segment's pbufs are used by someone else than TCP.
|
---|
| 1423 | * This can happen on retransmission if the pbuf of this segment is still
|
---|
| 1424 | * referenced by the netif driver due to deferred transmission.
|
---|
| 1425 | * This is the case (only!) if someone down the TX call path called
|
---|
| 1426 | * pbuf_ref() on one of the pbufs!
|
---|
| 1427 | *
|
---|
| 1428 | * @arg seg the tcp segment to check
|
---|
| 1429 | * @return 1 if ref != 1, 0 if ref == 1
|
---|
| 1430 | */
|
---|
| 1431 | static int
|
---|
| 1432 | tcp_output_segment_busy(const struct tcp_seg *seg)
|
---|
| 1433 | {
|
---|
| 1434 | LWIP_ASSERT("tcp_output_segment_busy: invalid seg", seg != NULL);
|
---|
| 1435 |
|
---|
| 1436 | /* We only need to check the first pbuf here:
|
---|
| 1437 | If a pbuf is queued for transmission, a driver calls pbuf_ref(),
|
---|
| 1438 | which only changes the ref count of the first pbuf */
|
---|
| 1439 | if (seg->p->ref != 1) {
|
---|
| 1440 | /* other reference found */
|
---|
| 1441 | return 1;
|
---|
| 1442 | }
|
---|
| 1443 | /* no other references found */
|
---|
| 1444 | return 0;
|
---|
| 1445 | }
|
---|
| 1446 |
|
---|
| 1447 | /**
|
---|
| 1448 | * Called by tcp_output() to actually send a TCP segment over IP.
|
---|
| 1449 | *
|
---|
| 1450 | * @param seg the tcp_seg to send
|
---|
| 1451 | * @param pcb the tcp_pcb for the TCP connection used to send the segment
|
---|
| 1452 | * @param netif the netif used to send the segment
|
---|
| 1453 | */
|
---|
| 1454 | static err_t
|
---|
| 1455 | tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb, struct netif *netif)
|
---|
| 1456 | {
|
---|
| 1457 | err_t err;
|
---|
| 1458 | u16_t len;
|
---|
| 1459 | u32_t *opts;
|
---|
| 1460 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 1461 | int seg_chksum_was_swapped = 0;
|
---|
| 1462 | #endif
|
---|
| 1463 |
|
---|
| 1464 | LWIP_ASSERT("tcp_output_segment: invalid seg", seg != NULL);
|
---|
| 1465 | LWIP_ASSERT("tcp_output_segment: invalid pcb", pcb != NULL);
|
---|
| 1466 | LWIP_ASSERT("tcp_output_segment: invalid netif", netif != NULL);
|
---|
| 1467 |
|
---|
| 1468 | if (tcp_output_segment_busy(seg)) {
|
---|
| 1469 | /* This should not happen: rexmit functions should have checked this.
|
---|
| 1470 | However, since this function modifies p->len, we must not continue in this case. */
|
---|
| 1471 | LWIP_DEBUGF(TCP_RTO_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_output_segment: segment busy\n"));
|
---|
| 1472 | return ERR_OK;
|
---|
| 1473 | }
|
---|
| 1474 |
|
---|
| 1475 | /* The TCP header has already been constructed, but the ackno and
|
---|
| 1476 | wnd fields remain. */
|
---|
| 1477 | seg->tcphdr->ackno = lwip_htonl(pcb->rcv_nxt);
|
---|
| 1478 |
|
---|
| 1479 | /* advertise our receive window size in this TCP segment */
|
---|
| 1480 | #if LWIP_WND_SCALE
|
---|
| 1481 | if (seg->flags & TF_SEG_OPTS_WND_SCALE) {
|
---|
| 1482 | /* The Window field in a SYN segment itself (the only type where we send
|
---|
| 1483 | the window scale option) is never scaled. */
|
---|
| 1484 | seg->tcphdr->wnd = lwip_htons(TCPWND_MIN16(pcb->rcv_ann_wnd));
|
---|
| 1485 | } else
|
---|
| 1486 | #endif /* LWIP_WND_SCALE */
|
---|
| 1487 | {
|
---|
| 1488 | seg->tcphdr->wnd = lwip_htons(TCPWND_MIN16(RCV_WND_SCALE(pcb, pcb->rcv_ann_wnd)));
|
---|
| 1489 | }
|
---|
| 1490 |
|
---|
| 1491 | pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
|
---|
| 1492 |
|
---|
| 1493 | /* Add any requested options. NB MSS option is only set on SYN
|
---|
| 1494 | packets, so ignore it here */
|
---|
| 1495 | /* cast through void* to get rid of alignment warnings */
|
---|
| 1496 | opts = (u32_t *)(void *)(seg->tcphdr + 1);
|
---|
| 1497 | if (seg->flags & TF_SEG_OPTS_MSS) {
|
---|
| 1498 | u16_t mss;
|
---|
| 1499 | #if TCP_CALCULATE_EFF_SEND_MSS
|
---|
| 1500 | mss = tcp_eff_send_mss_netif(TCP_MSS, netif, &pcb->remote_ip);
|
---|
| 1501 | #else /* TCP_CALCULATE_EFF_SEND_MSS */
|
---|
| 1502 | mss = TCP_MSS;
|
---|
| 1503 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */
|
---|
| 1504 | *opts = TCP_BUILD_MSS_OPTION(mss);
|
---|
| 1505 | opts += 1;
|
---|
| 1506 | }
|
---|
| 1507 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 1508 | pcb->ts_lastacksent = pcb->rcv_nxt;
|
---|
| 1509 |
|
---|
| 1510 | if (seg->flags & TF_SEG_OPTS_TS) {
|
---|
| 1511 | tcp_build_timestamp_option(pcb, opts);
|
---|
| 1512 | opts += 3;
|
---|
| 1513 | }
|
---|
| 1514 | #endif
|
---|
| 1515 | #if LWIP_WND_SCALE
|
---|
| 1516 | if (seg->flags & TF_SEG_OPTS_WND_SCALE) {
|
---|
| 1517 | tcp_build_wnd_scale_option(opts);
|
---|
| 1518 | opts += 1;
|
---|
| 1519 | }
|
---|
| 1520 | #endif
|
---|
| 1521 | #if LWIP_TCP_SACK_OUT
|
---|
| 1522 | if (seg->flags & TF_SEG_OPTS_SACK_PERM) {
|
---|
| 1523 | /* Pad with two NOP options to make everything nicely aligned
|
---|
| 1524 | * NOTE: When we send both timestamp and SACK_PERM options,
|
---|
| 1525 | * we could use the first two NOPs before the timestamp to store SACK_PERM option,
|
---|
| 1526 | * but that would complicate the code.
|
---|
| 1527 | */
|
---|
| 1528 | *(opts++) = PP_HTONL(0x01010402);
|
---|
| 1529 | }
|
---|
| 1530 | #endif
|
---|
| 1531 |
|
---|
| 1532 | /* Set retransmission timer running if it is not currently enabled
|
---|
| 1533 | This must be set before checking the route. */
|
---|
| 1534 | if (pcb->rtime < 0) {
|
---|
| 1535 | pcb->rtime = 0;
|
---|
| 1536 | }
|
---|
| 1537 |
|
---|
| 1538 | if (pcb->rttest == 0) {
|
---|
| 1539 | pcb->rttest = tcp_ticks;
|
---|
| 1540 | pcb->rtseq = lwip_ntohl(seg->tcphdr->seqno);
|
---|
| 1541 |
|
---|
| 1542 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
|
---|
| 1543 | }
|
---|
| 1544 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
|
---|
| 1545 | lwip_htonl(seg->tcphdr->seqno), lwip_htonl(seg->tcphdr->seqno) +
|
---|
| 1546 | seg->len));
|
---|
| 1547 |
|
---|
| 1548 | len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
|
---|
| 1549 | if (len == 0) {
|
---|
| 1550 | /** Exclude retransmitted segments from this count. */
|
---|
| 1551 | MIB2_STATS_INC(mib2.tcpoutsegs);
|
---|
| 1552 | }
|
---|
| 1553 |
|
---|
| 1554 | seg->p->len -= len;
|
---|
| 1555 | seg->p->tot_len -= len;
|
---|
| 1556 |
|
---|
| 1557 | seg->p->payload = seg->tcphdr;
|
---|
| 1558 |
|
---|
| 1559 | seg->tcphdr->chksum = 0;
|
---|
| 1560 |
|
---|
| 1561 | #ifdef LWIP_HOOK_TCP_OUT_ADD_TCPOPTS
|
---|
| 1562 | opts = LWIP_HOOK_TCP_OUT_ADD_TCPOPTS(seg->p, seg->tcphdr, pcb, opts);
|
---|
| 1563 | #endif
|
---|
| 1564 | LWIP_ASSERT("options not filled", (u8_t *)opts == ((u8_t *)(seg->tcphdr + 1)) + LWIP_TCP_OPT_LENGTH_SEGMENT(seg->flags, pcb));
|
---|
| 1565 |
|
---|
| 1566 | #if CHECKSUM_GEN_TCP
|
---|
| 1567 | IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_TCP) {
|
---|
| 1568 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 1569 | u32_t acc;
|
---|
| 1570 | #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
---|
| 1571 | u16_t chksum_slow = ip_chksum_pseudo(seg->p, IP_PROTO_TCP,
|
---|
| 1572 | seg->p->tot_len, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 1573 | #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
---|
| 1574 | if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
|
---|
| 1575 | LWIP_ASSERT("data included but not checksummed",
|
---|
| 1576 | seg->p->tot_len == TCPH_HDRLEN_BYTES(seg->tcphdr));
|
---|
| 1577 | }
|
---|
| 1578 |
|
---|
| 1579 | /* rebuild TCP header checksum (TCP header changes for retransmissions!) */
|
---|
| 1580 | acc = ip_chksum_pseudo_partial(seg->p, IP_PROTO_TCP,
|
---|
| 1581 | seg->p->tot_len, TCPH_HDRLEN_BYTES(seg->tcphdr), &pcb->local_ip, &pcb->remote_ip);
|
---|
| 1582 | /* add payload checksum */
|
---|
| 1583 | if (seg->chksum_swapped) {
|
---|
| 1584 | seg_chksum_was_swapped = 1;
|
---|
| 1585 | seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
|
---|
| 1586 | seg->chksum_swapped = 0;
|
---|
| 1587 | }
|
---|
| 1588 | acc = (u16_t)~acc + seg->chksum;
|
---|
| 1589 | seg->tcphdr->chksum = (u16_t)~FOLD_U32T(acc);
|
---|
| 1590 | #if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
---|
| 1591 | if (chksum_slow != seg->tcphdr->chksum) {
|
---|
| 1592 | TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL(
|
---|
| 1593 | ("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
|
---|
| 1594 | seg->tcphdr->chksum, chksum_slow));
|
---|
| 1595 | seg->tcphdr->chksum = chksum_slow;
|
---|
| 1596 | }
|
---|
| 1597 | #endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
---|
| 1598 | #else /* TCP_CHECKSUM_ON_COPY */
|
---|
| 1599 | seg->tcphdr->chksum = ip_chksum_pseudo(seg->p, IP_PROTO_TCP,
|
---|
| 1600 | seg->p->tot_len, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 1601 | #endif /* TCP_CHECKSUM_ON_COPY */
|
---|
| 1602 | }
|
---|
| 1603 | #endif /* CHECKSUM_GEN_TCP */
|
---|
| 1604 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1605 |
|
---|
| 1606 | NETIF_SET_HINTS(netif, &(pcb->netif_hints));
|
---|
| 1607 | err = ip_output_if(seg->p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl,
|
---|
| 1608 | pcb->tos, IP_PROTO_TCP, netif);
|
---|
| 1609 | NETIF_RESET_HINTS(netif);
|
---|
| 1610 |
|
---|
| 1611 | #if TCP_CHECKSUM_ON_COPY
|
---|
| 1612 | if (seg_chksum_was_swapped) {
|
---|
| 1613 | /* if data is added to this segment later, chksum needs to be swapped,
|
---|
| 1614 | so restore this now */
|
---|
| 1615 | seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
|
---|
| 1616 | seg->chksum_swapped = 1;
|
---|
| 1617 | }
|
---|
| 1618 | #endif
|
---|
| 1619 |
|
---|
| 1620 | return err;
|
---|
| 1621 | }
|
---|
| 1622 |
|
---|
| 1623 | /**
|
---|
| 1624 | * Requeue all unacked segments for retransmission
|
---|
| 1625 | *
|
---|
| 1626 | * Called by tcp_slowtmr() for slow retransmission.
|
---|
| 1627 | *
|
---|
| 1628 | * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
---|
| 1629 | */
|
---|
| 1630 | err_t
|
---|
| 1631 | tcp_rexmit_rto_prepare(struct tcp_pcb *pcb)
|
---|
| 1632 | {
|
---|
| 1633 | struct tcp_seg *seg;
|
---|
| 1634 |
|
---|
| 1635 | LWIP_ASSERT("tcp_rexmit_rto_prepare: invalid pcb", pcb != NULL);
|
---|
| 1636 |
|
---|
| 1637 | if (pcb->unacked == NULL) {
|
---|
| 1638 | return ERR_VAL;
|
---|
| 1639 | }
|
---|
| 1640 |
|
---|
| 1641 | /* Move all unacked segments to the head of the unsent queue.
|
---|
| 1642 | However, give up if any of the unsent pbufs are still referenced by the
|
---|
| 1643 | netif driver due to deferred transmission. No point loading the link further
|
---|
| 1644 | if it is struggling to flush its buffered writes. */
|
---|
| 1645 | for (seg = pcb->unacked; seg->next != NULL; seg = seg->next) {
|
---|
| 1646 | if (tcp_output_segment_busy(seg)) {
|
---|
| 1647 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit_rto: segment busy\n"));
|
---|
| 1648 | return ERR_VAL;
|
---|
| 1649 | }
|
---|
| 1650 | }
|
---|
| 1651 | if (tcp_output_segment_busy(seg)) {
|
---|
| 1652 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit_rto: segment busy\n"));
|
---|
| 1653 | return ERR_VAL;
|
---|
| 1654 | }
|
---|
| 1655 | /* concatenate unsent queue after unacked queue */
|
---|
| 1656 | seg->next = pcb->unsent;
|
---|
| 1657 | #if TCP_OVERSIZE_DBGCHECK
|
---|
| 1658 | /* if last unsent changed, we need to update unsent_oversize */
|
---|
| 1659 | if (pcb->unsent == NULL) {
|
---|
| 1660 | pcb->unsent_oversize = seg->oversize_left;
|
---|
| 1661 | }
|
---|
| 1662 | #endif /* TCP_OVERSIZE_DBGCHECK */
|
---|
| 1663 | /* unsent queue is the concatenated queue (of unacked, unsent) */
|
---|
| 1664 | pcb->unsent = pcb->unacked;
|
---|
| 1665 | /* unacked queue is now empty */
|
---|
| 1666 | pcb->unacked = NULL;
|
---|
| 1667 |
|
---|
| 1668 | /* Mark RTO in-progress */
|
---|
| 1669 | tcp_set_flags(pcb, TF_RTO);
|
---|
| 1670 | /* Record the next byte following retransmit */
|
---|
| 1671 | pcb->rto_end = lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
|
---|
| 1672 | /* Don't take any RTT measurements after retransmitting. */
|
---|
| 1673 | pcb->rttest = 0;
|
---|
| 1674 |
|
---|
| 1675 | return ERR_OK;
|
---|
| 1676 | }
|
---|
| 1677 |
|
---|
| 1678 | /**
|
---|
| 1679 | * Requeue all unacked segments for retransmission
|
---|
| 1680 | *
|
---|
| 1681 | * Called by tcp_slowtmr() for slow retransmission.
|
---|
| 1682 | *
|
---|
| 1683 | * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
---|
| 1684 | */
|
---|
| 1685 | void
|
---|
| 1686 | tcp_rexmit_rto_commit(struct tcp_pcb *pcb)
|
---|
| 1687 | {
|
---|
| 1688 | LWIP_ASSERT("tcp_rexmit_rto_commit: invalid pcb", pcb != NULL);
|
---|
| 1689 |
|
---|
| 1690 | /* increment number of retransmissions */
|
---|
| 1691 | if (pcb->nrtx < 0xFF) {
|
---|
| 1692 | ++pcb->nrtx;
|
---|
| 1693 | }
|
---|
| 1694 | /* Do the actual retransmission */
|
---|
| 1695 | tcp_output(pcb);
|
---|
| 1696 | }
|
---|
| 1697 |
|
---|
| 1698 | /**
|
---|
| 1699 | * Requeue all unacked segments for retransmission
|
---|
| 1700 | *
|
---|
| 1701 | * Called by tcp_process() only, tcp_slowtmr() needs to do some things between
|
---|
| 1702 | * "prepare" and "commit".
|
---|
| 1703 | *
|
---|
| 1704 | * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
---|
| 1705 | */
|
---|
| 1706 | void
|
---|
| 1707 | tcp_rexmit_rto(struct tcp_pcb *pcb)
|
---|
| 1708 | {
|
---|
| 1709 | LWIP_ASSERT("tcp_rexmit_rto: invalid pcb", pcb != NULL);
|
---|
| 1710 |
|
---|
| 1711 | if (tcp_rexmit_rto_prepare(pcb) == ERR_OK) {
|
---|
| 1712 | tcp_rexmit_rto_commit(pcb);
|
---|
| 1713 | }
|
---|
| 1714 | }
|
---|
| 1715 |
|
---|
| 1716 | /**
|
---|
| 1717 | * Requeue the first unacked segment for retransmission
|
---|
| 1718 | *
|
---|
| 1719 | * Called by tcp_receive() for fast retransmit.
|
---|
| 1720 | *
|
---|
| 1721 | * @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
---|
| 1722 | */
|
---|
| 1723 | err_t
|
---|
| 1724 | tcp_rexmit(struct tcp_pcb *pcb)
|
---|
| 1725 | {
|
---|
| 1726 | struct tcp_seg *seg;
|
---|
| 1727 | struct tcp_seg **cur_seg;
|
---|
| 1728 |
|
---|
| 1729 | LWIP_ASSERT("tcp_rexmit: invalid pcb", pcb != NULL);
|
---|
| 1730 |
|
---|
| 1731 | if (pcb->unacked == NULL) {
|
---|
| 1732 | return ERR_VAL;
|
---|
| 1733 | }
|
---|
| 1734 |
|
---|
| 1735 | seg = pcb->unacked;
|
---|
| 1736 |
|
---|
| 1737 | /* Give up if the segment is still referenced by the netif driver
|
---|
| 1738 | due to deferred transmission. */
|
---|
| 1739 | if (tcp_output_segment_busy(seg)) {
|
---|
| 1740 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit busy\n"));
|
---|
| 1741 | return ERR_VAL;
|
---|
| 1742 | }
|
---|
| 1743 |
|
---|
| 1744 | /* Move the first unacked segment to the unsent queue */
|
---|
| 1745 | /* Keep the unsent queue sorted. */
|
---|
| 1746 | pcb->unacked = seg->next;
|
---|
| 1747 |
|
---|
| 1748 | cur_seg = &(pcb->unsent);
|
---|
| 1749 | while (*cur_seg &&
|
---|
| 1750 | TCP_SEQ_LT(lwip_ntohl((*cur_seg)->tcphdr->seqno), lwip_ntohl(seg->tcphdr->seqno))) {
|
---|
| 1751 | cur_seg = &((*cur_seg)->next );
|
---|
| 1752 | }
|
---|
| 1753 | seg->next = *cur_seg;
|
---|
| 1754 | *cur_seg = seg;
|
---|
| 1755 | #if TCP_OVERSIZE
|
---|
| 1756 | if (seg->next == NULL) {
|
---|
| 1757 | /* the retransmitted segment is last in unsent, so reset unsent_oversize */
|
---|
| 1758 | pcb->unsent_oversize = 0;
|
---|
| 1759 | }
|
---|
| 1760 | #endif /* TCP_OVERSIZE */
|
---|
| 1761 |
|
---|
| 1762 | if (pcb->nrtx < 0xFF) {
|
---|
| 1763 | ++pcb->nrtx;
|
---|
| 1764 | }
|
---|
| 1765 |
|
---|
| 1766 | /* Don't take any rtt measurements after retransmitting. */
|
---|
| 1767 | pcb->rttest = 0;
|
---|
| 1768 |
|
---|
| 1769 | /* Do the actual retransmission. */
|
---|
| 1770 | MIB2_STATS_INC(mib2.tcpretranssegs);
|
---|
| 1771 | /* No need to call tcp_output: we are always called from tcp_input()
|
---|
| 1772 | and thus tcp_output directly returns. */
|
---|
| 1773 | return ERR_OK;
|
---|
| 1774 | }
|
---|
| 1775 |
|
---|
| 1776 |
|
---|
| 1777 | /**
|
---|
| 1778 | * Handle retransmission after three dupacks received
|
---|
| 1779 | *
|
---|
| 1780 | * @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
---|
| 1781 | */
|
---|
| 1782 | void
|
---|
| 1783 | tcp_rexmit_fast(struct tcp_pcb *pcb)
|
---|
| 1784 | {
|
---|
| 1785 | LWIP_ASSERT("tcp_rexmit_fast: invalid pcb", pcb != NULL);
|
---|
| 1786 |
|
---|
| 1787 | if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
|
---|
| 1788 | /* This is fast retransmit. Retransmit the first unacked segment. */
|
---|
| 1789 | LWIP_DEBUGF(TCP_FR_DEBUG,
|
---|
| 1790 | ("tcp_receive: dupacks %"U16_F" (%"U32_F
|
---|
| 1791 | "), fast retransmit %"U32_F"\n",
|
---|
| 1792 | (u16_t)pcb->dupacks, pcb->lastack,
|
---|
| 1793 | lwip_ntohl(pcb->unacked->tcphdr->seqno)));
|
---|
| 1794 | if (tcp_rexmit(pcb) == ERR_OK) {
|
---|
| 1795 | /* Set ssthresh to half of the minimum of the current
|
---|
| 1796 | * cwnd and the advertised window */
|
---|
| 1797 | pcb->ssthresh = LWIP_MIN(pcb->cwnd, pcb->snd_wnd) / 2;
|
---|
| 1798 |
|
---|
| 1799 | /* The minimum value for ssthresh should be 2 MSS */
|
---|
| 1800 | if (pcb->ssthresh < (2U * pcb->mss)) {
|
---|
| 1801 | LWIP_DEBUGF(TCP_FR_DEBUG,
|
---|
| 1802 | ("tcp_receive: The minimum value for ssthresh %"TCPWNDSIZE_F
|
---|
| 1803 | " should be min 2 mss %"U16_F"...\n",
|
---|
| 1804 | pcb->ssthresh, (u16_t)(2 * pcb->mss)));
|
---|
| 1805 | pcb->ssthresh = 2 * pcb->mss;
|
---|
| 1806 | }
|
---|
| 1807 |
|
---|
| 1808 | pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
|
---|
| 1809 | tcp_set_flags(pcb, TF_INFR);
|
---|
| 1810 |
|
---|
| 1811 | /* Reset the retransmission timer to prevent immediate rto retransmissions */
|
---|
| 1812 | pcb->rtime = 0;
|
---|
| 1813 | }
|
---|
| 1814 | }
|
---|
| 1815 | }
|
---|
| 1816 |
|
---|
| 1817 | static struct pbuf *
|
---|
| 1818 | tcp_output_alloc_header_common(u32_t ackno, u16_t optlen, u16_t datalen,
|
---|
| 1819 | u32_t seqno_be /* already in network byte order */,
|
---|
| 1820 | u16_t src_port, u16_t dst_port, u8_t flags, u16_t wnd)
|
---|
| 1821 | {
|
---|
| 1822 | struct tcp_hdr *tcphdr;
|
---|
| 1823 | struct pbuf *p;
|
---|
| 1824 |
|
---|
| 1825 | p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
|
---|
| 1826 | if (p != NULL) {
|
---|
| 1827 | LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
|
---|
| 1828 | (p->len >= TCP_HLEN + optlen));
|
---|
| 1829 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1830 | tcphdr->src = lwip_htons(src_port);
|
---|
| 1831 | tcphdr->dest = lwip_htons(dst_port);
|
---|
| 1832 | tcphdr->seqno = seqno_be;
|
---|
| 1833 | tcphdr->ackno = lwip_htonl(ackno);
|
---|
| 1834 | TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), flags);
|
---|
| 1835 | tcphdr->wnd = lwip_htons(wnd);
|
---|
| 1836 | tcphdr->chksum = 0;
|
---|
| 1837 | tcphdr->urgp = 0;
|
---|
| 1838 | }
|
---|
| 1839 | return p;
|
---|
| 1840 | }
|
---|
| 1841 |
|
---|
| 1842 | /** Allocate a pbuf and create a tcphdr at p->payload, used for output
|
---|
| 1843 | * functions other than the default tcp_output -> tcp_output_segment
|
---|
| 1844 | * (e.g. tcp_send_empty_ack, etc.)
|
---|
| 1845 | *
|
---|
| 1846 | * @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
|
---|
| 1847 | * @param optlen length of header-options
|
---|
| 1848 | * @param datalen length of tcp data to reserve in pbuf
|
---|
| 1849 | * @param seqno_be seqno in network byte order (big-endian)
|
---|
| 1850 | * @return pbuf with p->payload being the tcp_hdr
|
---|
| 1851 | */
|
---|
| 1852 | static struct pbuf *
|
---|
| 1853 | tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
|
---|
| 1854 | u32_t seqno_be /* already in network byte order */)
|
---|
| 1855 | {
|
---|
| 1856 | struct pbuf *p;
|
---|
| 1857 |
|
---|
| 1858 | LWIP_ASSERT("tcp_output_alloc_header: invalid pcb", pcb != NULL);
|
---|
| 1859 |
|
---|
| 1860 | p = tcp_output_alloc_header_common(pcb->rcv_nxt, optlen, datalen,
|
---|
| 1861 | seqno_be, pcb->local_port, pcb->remote_port, TCP_ACK,
|
---|
| 1862 | TCPWND_MIN16(RCV_WND_SCALE(pcb, pcb->rcv_ann_wnd)));
|
---|
| 1863 | if (p != NULL) {
|
---|
| 1864 | /* If we're sending a packet, update the announced right window edge */
|
---|
| 1865 | pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
|
---|
| 1866 | }
|
---|
| 1867 | return p;
|
---|
| 1868 | }
|
---|
| 1869 |
|
---|
| 1870 | /* Fill in options for control segments */
|
---|
| 1871 | static void
|
---|
| 1872 | tcp_output_fill_options(const struct tcp_pcb *pcb, struct pbuf *p, u8_t optflags, u8_t num_sacks)
|
---|
| 1873 | {
|
---|
| 1874 | struct tcp_hdr *tcphdr;
|
---|
| 1875 | u32_t *opts;
|
---|
| 1876 | u16_t sacks_len = 0;
|
---|
| 1877 |
|
---|
| 1878 | LWIP_ASSERT("tcp_output_fill_options: invalid pbuf", p != NULL);
|
---|
| 1879 |
|
---|
| 1880 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1881 | opts = (u32_t *)(void *)(tcphdr + 1);
|
---|
| 1882 |
|
---|
| 1883 | /* NB. MSS and window scale options are only sent on SYNs, so ignore them here */
|
---|
| 1884 |
|
---|
| 1885 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 1886 | if (optflags & TF_SEG_OPTS_TS) {
|
---|
| 1887 | tcp_build_timestamp_option(pcb, opts);
|
---|
| 1888 | opts += 3;
|
---|
| 1889 | }
|
---|
| 1890 | #endif
|
---|
| 1891 |
|
---|
| 1892 | #if LWIP_TCP_SACK_OUT
|
---|
| 1893 | if (pcb && (num_sacks > 0)) {
|
---|
| 1894 | tcp_build_sack_option(pcb, opts, num_sacks);
|
---|
| 1895 | /* 1 word for SACKs header (including 2xNOP), and 2 words for each SACK */
|
---|
| 1896 | sacks_len = 1 + num_sacks * 2;
|
---|
| 1897 | opts += sacks_len;
|
---|
| 1898 | }
|
---|
| 1899 | #else
|
---|
| 1900 | LWIP_UNUSED_ARG(num_sacks);
|
---|
| 1901 | #endif
|
---|
| 1902 |
|
---|
| 1903 | #ifdef LWIP_HOOK_TCP_OUT_ADD_TCPOPTS
|
---|
| 1904 | opts = LWIP_HOOK_TCP_OUT_ADD_TCPOPTS(p, tcphdr, pcb, opts);
|
---|
| 1905 | #endif
|
---|
| 1906 |
|
---|
| 1907 | LWIP_UNUSED_ARG(pcb);
|
---|
| 1908 | LWIP_UNUSED_ARG(sacks_len);
|
---|
| 1909 | LWIP_ASSERT("options not filled", (u8_t *)opts == ((u8_t *)(tcphdr + 1)) + sacks_len * 4 + LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb));
|
---|
| 1910 | LWIP_UNUSED_ARG(optflags); /* for LWIP_NOASSERT */
|
---|
| 1911 | LWIP_UNUSED_ARG(opts); /* for LWIP_NOASSERT */
|
---|
| 1912 | }
|
---|
| 1913 |
|
---|
| 1914 | /** Output a control segment pbuf to IP.
|
---|
| 1915 | *
|
---|
| 1916 | * Called from tcp_rst, tcp_send_empty_ack, tcp_keepalive and tcp_zero_window_probe,
|
---|
| 1917 | * this function combines selecting a netif for transmission, generating the tcp
|
---|
| 1918 | * header checksum and calling ip_output_if while handling netif hints and stats.
|
---|
| 1919 | */
|
---|
| 1920 | static err_t
|
---|
| 1921 | tcp_output_control_segment(const struct tcp_pcb *pcb, struct pbuf *p,
|
---|
| 1922 | const ip_addr_t *src, const ip_addr_t *dst)
|
---|
| 1923 | {
|
---|
| 1924 | err_t err;
|
---|
| 1925 | struct netif *netif;
|
---|
| 1926 |
|
---|
| 1927 | LWIP_ASSERT("tcp_output_control_segment: invalid pbuf", p != NULL);
|
---|
| 1928 |
|
---|
| 1929 | netif = tcp_route(pcb, src, dst);
|
---|
| 1930 | if (netif == NULL) {
|
---|
| 1931 | err = ERR_RTE;
|
---|
| 1932 | } else {
|
---|
| 1933 | u8_t ttl, tos;
|
---|
| 1934 | #if CHECKSUM_GEN_TCP
|
---|
| 1935 | IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_TCP) {
|
---|
| 1936 | struct tcp_hdr *tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 1937 | tcphdr->chksum = ip_chksum_pseudo(p, IP_PROTO_TCP, p->tot_len,
|
---|
| 1938 | src, dst);
|
---|
| 1939 | }
|
---|
| 1940 | #endif
|
---|
| 1941 | if (pcb != NULL) {
|
---|
| 1942 | NETIF_SET_HINTS(netif, LWIP_CONST_CAST(struct netif_hint*, &(pcb->netif_hints)));
|
---|
| 1943 | ttl = pcb->ttl;
|
---|
| 1944 | tos = pcb->tos;
|
---|
| 1945 | } else {
|
---|
| 1946 | /* Send output with hardcoded TTL/HL since we have no access to the pcb */
|
---|
| 1947 | ttl = TCP_TTL;
|
---|
| 1948 | tos = 0;
|
---|
| 1949 | }
|
---|
| 1950 | TCP_STATS_INC(tcp.xmit);
|
---|
| 1951 | err = ip_output_if(p, src, dst, ttl, tos, IP_PROTO_TCP, netif);
|
---|
| 1952 | NETIF_RESET_HINTS(netif);
|
---|
| 1953 | }
|
---|
| 1954 | pbuf_free(p);
|
---|
| 1955 | return err;
|
---|
| 1956 | }
|
---|
| 1957 |
|
---|
| 1958 | /**
|
---|
| 1959 | * Send a TCP RESET packet (empty segment with RST flag set) either to
|
---|
| 1960 | * abort a connection or to show that there is no matching local connection
|
---|
| 1961 | * for a received segment.
|
---|
| 1962 | *
|
---|
| 1963 | * Called by tcp_abort() (to abort a local connection), tcp_input() (if no
|
---|
| 1964 | * matching local pcb was found), tcp_listen_input() (if incoming segment
|
---|
| 1965 | * has ACK flag set) and tcp_process() (received segment in the wrong state)
|
---|
| 1966 | *
|
---|
| 1967 | * Since a RST segment is in most cases not sent for an active connection,
|
---|
| 1968 | * tcp_rst() has a number of arguments that are taken from a tcp_pcb for
|
---|
| 1969 | * most other segment output functions.
|
---|
| 1970 | *
|
---|
| 1971 | * @param pcb TCP pcb (may be NULL if no pcb is available)
|
---|
| 1972 | * @param seqno the sequence number to use for the outgoing segment
|
---|
| 1973 | * @param ackno the acknowledge number to use for the outgoing segment
|
---|
| 1974 | * @param local_ip the local IP address to send the segment from
|
---|
| 1975 | * @param remote_ip the remote IP address to send the segment to
|
---|
| 1976 | * @param local_port the local TCP port to send the segment from
|
---|
| 1977 | * @param remote_port the remote TCP port to send the segment to
|
---|
| 1978 | */
|
---|
| 1979 | void
|
---|
| 1980 | tcp_rst(const struct tcp_pcb *pcb, u32_t seqno, u32_t ackno,
|
---|
| 1981 | const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
|
---|
| 1982 | u16_t local_port, u16_t remote_port)
|
---|
| 1983 | {
|
---|
| 1984 | struct pbuf *p;
|
---|
| 1985 | u16_t wnd;
|
---|
| 1986 | u8_t optlen;
|
---|
| 1987 |
|
---|
| 1988 | LWIP_ASSERT("tcp_rst: invalid local_ip", local_ip != NULL);
|
---|
| 1989 | LWIP_ASSERT("tcp_rst: invalid remote_ip", remote_ip != NULL);
|
---|
| 1990 |
|
---|
| 1991 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
---|
| 1992 |
|
---|
| 1993 | #if LWIP_WND_SCALE
|
---|
| 1994 | wnd = PP_HTONS(((TCP_WND >> TCP_RCV_SCALE) & 0xFFFF));
|
---|
| 1995 | #else
|
---|
| 1996 | wnd = PP_HTONS(TCP_WND);
|
---|
| 1997 | #endif
|
---|
| 1998 |
|
---|
| 1999 | p = tcp_output_alloc_header_common(ackno, optlen, 0, lwip_htonl(seqno), local_port,
|
---|
| 2000 | remote_port, TCP_RST | TCP_ACK, wnd);
|
---|
| 2001 | if (p == NULL) {
|
---|
| 2002 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
|
---|
| 2003 | return;
|
---|
| 2004 | }
|
---|
| 2005 | tcp_output_fill_options(pcb, p, 0, optlen);
|
---|
| 2006 |
|
---|
| 2007 | MIB2_STATS_INC(mib2.tcpoutrsts);
|
---|
| 2008 |
|
---|
| 2009 | tcp_output_control_segment(pcb, p, local_ip, remote_ip);
|
---|
| 2010 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
|
---|
| 2011 | }
|
---|
| 2012 |
|
---|
| 2013 | /**
|
---|
| 2014 | * Send an ACK without data.
|
---|
| 2015 | *
|
---|
| 2016 | * @param pcb Protocol control block for the TCP connection to send the ACK
|
---|
| 2017 | */
|
---|
| 2018 | err_t
|
---|
| 2019 | tcp_send_empty_ack(struct tcp_pcb *pcb)
|
---|
| 2020 | {
|
---|
| 2021 | err_t err;
|
---|
| 2022 | struct pbuf *p;
|
---|
| 2023 | u8_t optlen, optflags = 0;
|
---|
| 2024 | u8_t num_sacks = 0;
|
---|
| 2025 |
|
---|
| 2026 | LWIP_ASSERT("tcp_send_empty_ack: invalid pcb", pcb != NULL);
|
---|
| 2027 |
|
---|
| 2028 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 2029 | if (pcb->flags & TF_TIMESTAMP) {
|
---|
| 2030 | optflags = TF_SEG_OPTS_TS;
|
---|
| 2031 | }
|
---|
| 2032 | #endif
|
---|
| 2033 | optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
|
---|
| 2034 |
|
---|
| 2035 | #if LWIP_TCP_SACK_OUT
|
---|
| 2036 | /* For now, SACKs are only sent with empty ACKs */
|
---|
| 2037 | if ((num_sacks = tcp_get_num_sacks(pcb, optlen)) > 0) {
|
---|
| 2038 | optlen += 4 + num_sacks * 8; /* 4 bytes for header (including 2*NOP), plus 8B for each SACK */
|
---|
| 2039 | }
|
---|
| 2040 | #endif
|
---|
| 2041 |
|
---|
| 2042 | p = tcp_output_alloc_header(pcb, optlen, 0, lwip_htonl(pcb->snd_nxt));
|
---|
| 2043 | if (p == NULL) {
|
---|
| 2044 | /* let tcp_fasttmr retry sending this ACK */
|
---|
| 2045 | tcp_set_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 2046 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
|
---|
| 2047 | return ERR_BUF;
|
---|
| 2048 | }
|
---|
| 2049 | tcp_output_fill_options(pcb, p, optflags, num_sacks);
|
---|
| 2050 |
|
---|
| 2051 | #if LWIP_TCP_TIMESTAMPS
|
---|
| 2052 | pcb->ts_lastacksent = pcb->rcv_nxt;
|
---|
| 2053 | #endif
|
---|
| 2054 |
|
---|
| 2055 | LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
|
---|
| 2056 | ("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
|
---|
| 2057 | err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 2058 | if (err != ERR_OK) {
|
---|
| 2059 | /* let tcp_fasttmr retry sending this ACK */
|
---|
| 2060 | tcp_set_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 2061 | } else {
|
---|
| 2062 | /* remove ACK flags from the PCB, as we sent an empty ACK now */
|
---|
| 2063 | tcp_clear_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
---|
| 2064 | }
|
---|
| 2065 |
|
---|
| 2066 | return err;
|
---|
| 2067 | }
|
---|
| 2068 |
|
---|
| 2069 | /**
|
---|
| 2070 | * Send keepalive packets to keep a connection active although
|
---|
| 2071 | * no data is sent over it.
|
---|
| 2072 | *
|
---|
| 2073 | * Called by tcp_slowtmr()
|
---|
| 2074 | *
|
---|
| 2075 | * @param pcb the tcp_pcb for which to send a keepalive packet
|
---|
| 2076 | */
|
---|
| 2077 | err_t
|
---|
| 2078 | tcp_keepalive(struct tcp_pcb *pcb)
|
---|
| 2079 | {
|
---|
| 2080 | err_t err;
|
---|
| 2081 | struct pbuf *p;
|
---|
| 2082 | u8_t optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
---|
| 2083 |
|
---|
| 2084 | LWIP_ASSERT("tcp_keepalive: invalid pcb", pcb != NULL);
|
---|
| 2085 |
|
---|
| 2086 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to "));
|
---|
| 2087 | ip_addr_debug_print_val(TCP_DEBUG, pcb->remote_ip);
|
---|
| 2088 | LWIP_DEBUGF(TCP_DEBUG, ("\n"));
|
---|
| 2089 |
|
---|
| 2090 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
---|
| 2091 | tcp_ticks, pcb->tmr, (u16_t)pcb->keep_cnt_sent));
|
---|
| 2092 |
|
---|
| 2093 | p = tcp_output_alloc_header(pcb, optlen, 0, lwip_htonl(pcb->snd_nxt - 1));
|
---|
| 2094 | if (p == NULL) {
|
---|
| 2095 | LWIP_DEBUGF(TCP_DEBUG,
|
---|
| 2096 | ("tcp_keepalive: could not allocate memory for pbuf\n"));
|
---|
| 2097 | return ERR_MEM;
|
---|
| 2098 | }
|
---|
| 2099 | tcp_output_fill_options(pcb, p, 0, optlen);
|
---|
| 2100 | err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 2101 |
|
---|
| 2102 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F" err %d.\n",
|
---|
| 2103 | pcb->snd_nxt - 1, pcb->rcv_nxt, (int)err));
|
---|
| 2104 | return err;
|
---|
| 2105 | }
|
---|
| 2106 |
|
---|
| 2107 | /**
|
---|
| 2108 | * Send persist timer zero-window probes to keep a connection active
|
---|
| 2109 | * when a window update is lost.
|
---|
| 2110 | *
|
---|
| 2111 | * Called by tcp_slowtmr()
|
---|
| 2112 | *
|
---|
| 2113 | * @param pcb the tcp_pcb for which to send a zero-window probe packet
|
---|
| 2114 | */
|
---|
| 2115 | err_t
|
---|
| 2116 | tcp_zero_window_probe(struct tcp_pcb *pcb)
|
---|
| 2117 | {
|
---|
| 2118 | err_t err;
|
---|
| 2119 | struct pbuf *p;
|
---|
| 2120 | struct tcp_hdr *tcphdr;
|
---|
| 2121 | struct tcp_seg *seg;
|
---|
| 2122 | u16_t len;
|
---|
| 2123 | u8_t is_fin;
|
---|
| 2124 | u32_t snd_nxt;
|
---|
| 2125 | u8_t optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
---|
| 2126 |
|
---|
| 2127 | LWIP_ASSERT("tcp_zero_window_probe: invalid pcb", pcb != NULL);
|
---|
| 2128 |
|
---|
| 2129 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: sending ZERO WINDOW probe to "));
|
---|
| 2130 | ip_addr_debug_print_val(TCP_DEBUG, pcb->remote_ip);
|
---|
| 2131 | LWIP_DEBUGF(TCP_DEBUG, ("\n"));
|
---|
| 2132 |
|
---|
| 2133 | LWIP_DEBUGF(TCP_DEBUG,
|
---|
| 2134 | ("tcp_zero_window_probe: tcp_ticks %"U32_F
|
---|
| 2135 | " pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
---|
| 2136 | tcp_ticks, pcb->tmr, (u16_t)pcb->keep_cnt_sent));
|
---|
| 2137 |
|
---|
| 2138 | /* Only consider unsent, persist timer should be off when there is data in-flight */
|
---|
| 2139 | seg = pcb->unsent;
|
---|
| 2140 | if (seg == NULL) {
|
---|
| 2141 | /* Not expected, persist timer should be off when the send buffer is empty */
|
---|
| 2142 | return ERR_OK;
|
---|
| 2143 | }
|
---|
| 2144 |
|
---|
| 2145 | /* increment probe count. NOTE: we record probe even if it fails
|
---|
| 2146 | to actually transmit due to an error. This ensures memory exhaustion/
|
---|
| 2147 | routing problem doesn't leave a zero-window pcb as an indefinite zombie.
|
---|
| 2148 | RTO mechanism has similar behavior, see pcb->nrtx */
|
---|
| 2149 | if (pcb->persist_probe < 0xFF) {
|
---|
| 2150 | ++pcb->persist_probe;
|
---|
| 2151 | }
|
---|
| 2152 |
|
---|
| 2153 | is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
|
---|
| 2154 | /* we want to send one seqno: either FIN or data (no options) */
|
---|
| 2155 | len = is_fin ? 0 : 1;
|
---|
| 2156 |
|
---|
| 2157 | p = tcp_output_alloc_header(pcb, optlen, len, seg->tcphdr->seqno);
|
---|
| 2158 | if (p == NULL) {
|
---|
| 2159 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
|
---|
| 2160 | return ERR_MEM;
|
---|
| 2161 | }
|
---|
| 2162 | tcphdr = (struct tcp_hdr *)p->payload;
|
---|
| 2163 |
|
---|
| 2164 | if (is_fin) {
|
---|
| 2165 | /* FIN segment, no data */
|
---|
| 2166 | TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
|
---|
| 2167 | } else {
|
---|
| 2168 | /* Data segment, copy in one byte from the head of the unacked queue */
|
---|
| 2169 | char *d = ((char *)p->payload + TCP_HLEN);
|
---|
| 2170 | /* Depending on whether the segment has already been sent (unacked) or not
|
---|
| 2171 | (unsent), seg->p->payload points to the IP header or TCP header.
|
---|
| 2172 | Ensure we copy the first TCP data byte: */
|
---|
| 2173 | pbuf_copy_partial(seg->p, d, 1, seg->p->tot_len - seg->len);
|
---|
| 2174 | }
|
---|
| 2175 |
|
---|
| 2176 | /* The byte may be acknowledged without the window being opened. */
|
---|
| 2177 | snd_nxt = lwip_ntohl(seg->tcphdr->seqno) + 1;
|
---|
| 2178 | if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
---|
| 2179 | pcb->snd_nxt = snd_nxt;
|
---|
| 2180 | }
|
---|
| 2181 | tcp_output_fill_options(pcb, p, 0, optlen);
|
---|
| 2182 |
|
---|
| 2183 | err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
---|
| 2184 |
|
---|
| 2185 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
|
---|
| 2186 | " ackno %"U32_F" err %d.\n",
|
---|
| 2187 | pcb->snd_nxt - 1, pcb->rcv_nxt, (int)err));
|
---|
| 2188 | return err;
|
---|
| 2189 | }
|
---|
| 2190 | #endif /* LWIP_TCP */
|
---|