1 | /* $Id: tcp_output.c 98103 2023-01-17 14:15:46Z vboxsync $ */
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2 | /** @file
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3 | * NAT - TCP output.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2006-2023 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * SPDX-License-Identifier: GPL-3.0-only
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26 | */
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27 |
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28 | /*
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29 | * This code is based on:
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30 | *
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31 | * Copyright (c) 1982, 1986, 1988, 1990, 1993
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32 | * The Regents of the University of California. All rights reserved.
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33 | *
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34 | * Redistribution and use in source and binary forms, with or without
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35 | * modification, are permitted provided that the following conditions
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36 | * are met:
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37 | * 1. Redistributions of source code must retain the above copyright
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38 | * notice, this list of conditions and the following disclaimer.
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39 | * 2. Redistributions in binary form must reproduce the above copyright
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40 | * notice, this list of conditions and the following disclaimer in the
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41 | * documentation and/or other materials provided with the distribution.
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42 | * 3. Neither the name of the University nor the names of its contributors
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43 | * may be used to endorse or promote products derived from this software
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44 | * without specific prior written permission.
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45 | *
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46 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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47 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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48 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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49 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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50 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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51 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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52 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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53 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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54 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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55 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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56 | * SUCH DAMAGE.
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57 | *
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58 | * @(#)tcp_output.c 8.3 (Berkeley) 12/30/93
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59 | * tcp_output.c,v 1.3 1994/09/15 10:36:55 davidg Exp
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60 | */
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61 |
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62 | /*
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63 | * Changes and additions relating to SLiRP
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64 | * Copyright (c) 1995 Danny Gasparovski.
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65 | *
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66 | * Please read the file COPYRIGHT for the
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67 | * terms and conditions of the copyright.
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68 | */
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69 |
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70 | #include <slirp.h>
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71 |
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72 | /*
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73 | * Since this is only used in "stats socket", we give meaning
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74 | * names instead of the REAL names
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75 | */
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76 | const char * const tcpstates[] =
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77 | {
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78 | /* "CLOSED", "LISTEN", "SYN_SENT", "SYN_RCVD", */
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79 | "REDIRECT", "LISTEN", "SYN_SENT", "SYN_RCVD",
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80 | "ESTABLISHED", "CLOSE_WAIT", "FIN_WAIT_1", "CLOSING",
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81 | "LAST_ACK", "FIN_WAIT_2", "TIME_WAIT",
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82 | };
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83 |
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84 | static const u_char tcp_outflags[TCP_NSTATES] =
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85 | {
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86 | TH_RST|TH_ACK, 0, TH_SYN, TH_SYN|TH_ACK,
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87 | TH_ACK, TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK,
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88 | TH_FIN|TH_ACK, TH_ACK, TH_ACK,
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89 | };
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90 |
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91 |
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92 | #define MAX_TCPOPTLEN 32 /* max # bytes that go in options */
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93 |
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94 | /*
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95 | * Tcp output routine: figure out what should be sent and send it.
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96 | */
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97 | int
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98 | tcp_output(PNATState pData, register struct tcpcb *tp)
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99 | {
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100 | register struct socket *so = tp->t_socket;
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101 | register long len, win;
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102 | int off, flags, error;
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103 | register struct mbuf *m = NULL;
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104 | register struct tcpiphdr *ti;
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105 | u_char opt[MAX_TCPOPTLEN];
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106 | unsigned optlen, hdrlen;
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107 | int idle, sendalot;
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108 | int size = 0;
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109 |
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110 | LogFlowFunc(("ENTER: tcp_output: tp = %R[tcpcb793]\n", tp));
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111 |
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112 | /*
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113 | * Determine length of data that should be transmitted,
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114 | * and flags that will be used.
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115 | * If there is some data or critical controls (SYN, RST)
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116 | * to send, then transmit; otherwise, investigate further.
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117 | */
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118 | idle = (tp->snd_max == tp->snd_una);
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119 | if (idle && tp->t_idle >= tp->t_rxtcur)
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120 | /*
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121 | * We have been idle for "a while" and no acks are
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122 | * expected to clock out any data we send --
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123 | * slow start to get ack "clock" running again.
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124 | */
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125 | tp->snd_cwnd = tp->t_maxseg;
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126 |
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127 | again:
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128 | sendalot = 0;
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129 | off = tp->snd_nxt - tp->snd_una;
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130 | win = min(tp->snd_wnd, tp->snd_cwnd);
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131 |
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132 | flags = tcp_outflags[tp->t_state];
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133 |
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134 | Log2((" --- tcp_output flags = 0x%x\n", flags));
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135 |
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136 | /*
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137 | * If in persist timeout with window of 0, send 1 byte.
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138 | * Otherwise, if window is small but nonzero
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139 | * and timer expired, we will send what we can
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140 | * and go to transmit state.
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141 | */
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142 | if (tp->t_force)
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143 | {
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144 | if (win == 0)
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145 | {
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146 | /*
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147 | * If we still have some data to send, then
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148 | * clear the FIN bit. Usually this would
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149 | * happen below when it realizes that we
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150 | * aren't sending all the data. However,
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151 | * if we have exactly 1 byte of unset data,
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152 | * then it won't clear the FIN bit below,
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153 | * and if we are in persist state, we wind
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154 | * up sending the packet without recording
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155 | * that we sent the FIN bit.
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156 | *
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157 | * We can't just blindly clear the FIN bit,
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158 | * because if we don't have any more data
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159 | * to send then the probe will be the FIN
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160 | * itself.
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161 | */
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162 | if (off < SBUF_LEN(&so->so_snd))
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163 | flags &= ~TH_FIN;
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164 | win = 1;
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165 | }
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166 | else
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167 | {
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168 | tp->t_timer[TCPT_PERSIST] = 0;
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169 | tp->t_rxtshift = 0;
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170 | }
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171 | }
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172 |
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173 | len = min(SBUF_LEN(&so->so_snd), win) - off;
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174 | if (len < 0)
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175 | {
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176 | /*
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177 | * If FIN has been sent but not acked,
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178 | * but we haven't been called to retransmit,
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179 | * len will be -1. Otherwise, window shrank
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180 | * after we sent into it. If window shrank to 0,
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181 | * cancel pending retransmit and pull snd_nxt
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182 | * back to (closed) window. We will enter persist
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183 | * state below. If the window didn't close completely,
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184 | * just wait for an ACK.
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185 | */
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186 | len = 0;
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187 | if (win == 0)
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188 | {
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189 | tp->t_timer[TCPT_REXMT] = 0;
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190 | tp->snd_nxt = tp->snd_una;
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191 | }
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192 | }
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193 | if (len > tp->t_maxseg)
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194 | {
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195 | len = tp->t_maxseg;
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196 | sendalot = 1;
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197 | }
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198 | if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + SBUF_LEN(&so->so_snd)))
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199 | flags &= ~TH_FIN;
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200 |
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201 | win = sbspace(&so->so_rcv);
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202 |
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203 | /*
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204 | * Sender silly window avoidance. If connection is idle
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205 | * and can send all data, a maximum segment,
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206 | * at least a maximum default-size segment do it,
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207 | * or are forced, do it; otherwise don't bother.
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208 | * If peer's buffer is tiny, then send
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209 | * when window is at least half open.
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210 | * If retransmitting (possibly after persist timer forced us
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211 | * to send into a small window), then must resend.
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212 | */
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213 | if (len)
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214 | {
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215 | if (len == tp->t_maxseg)
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216 | goto send;
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217 | if ((1 || idle || tp->t_flags & TF_NODELAY) &&
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218 | len + off >= SBUF_LEN(&so->so_snd))
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219 | goto send;
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220 | if (tp->t_force)
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221 | goto send;
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222 | if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
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223 | goto send;
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224 | if (SEQ_LT(tp->snd_nxt, tp->snd_max))
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225 | goto send;
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226 | }
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227 |
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228 | /*
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229 | * Compare available window to amount of window
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230 | * known to peer (as advertised window less
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231 | * next expected input). If the difference is at least two
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232 | * max size segments, or at least 50% of the maximum possible
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233 | * window, then want to send a window update to peer.
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234 | */
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235 | if (win > 0)
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236 | {
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237 | /*
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238 | * "adv" is the amount we can increase the window,
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239 | * taking into account that we are limited by
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240 | * TCP_MAXWIN << tp->rcv_scale.
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241 | */
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242 | long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale);
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243 | if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt))
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244 | adv -= tp->rcv_adv - tp->rcv_nxt;
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245 |
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246 | if (adv >= (long) (2 * tp->t_maxseg))
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247 | goto send;
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248 | if (2 * adv >= (long) SBUF_SIZE(&so->so_rcv))
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249 | goto send;
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250 | }
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251 |
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252 | /*
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253 | * Send if we owe peer an ACK.
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254 | */
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255 | if (tp->t_flags & TF_ACKNOW)
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256 | goto send;
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257 | if (flags & (TH_SYN|TH_RST))
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258 | goto send;
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259 | if (SEQ_GT(tp->snd_up, tp->snd_una))
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260 | goto send;
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261 | /*
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262 | * If our state indicates that FIN should be sent
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263 | * and we have not yet done so, or we're retransmitting the FIN,
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264 | * then we need to send.
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265 | */
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266 | if ( flags & TH_FIN
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267 | && ((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una))
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268 | goto send;
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269 |
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270 | /*
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271 | * TCP window updates are not reliable, rather a polling protocol
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272 | * using ``persist'' packets is used to insure receipt of window
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273 | * updates. The three ``states'' for the output side are:
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274 | * idle not doing retransmits or persists
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275 | * persisting to move a small or zero window
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276 | * (re)transmitting and thereby not persisting
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277 | *
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278 | * tp->t_timer[TCPT_PERSIST]
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279 | * is set when we are in persist state.
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280 | * tp->t_force
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281 | * is set when we are called to send a persist packet.
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282 | * tp->t_timer[TCPT_REXMT]
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283 | * is set when we are retransmitting
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284 | * The output side is idle when both timers are zero.
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285 | *
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286 | * If send window is too small, there is data to transmit, and no
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287 | * retransmit or persist is pending, then go to persist state.
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288 | * If nothing happens soon, send when timer expires:
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289 | * if window is nonzero, transmit what we can,
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290 | * otherwise force out a byte.
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291 | */
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292 | if ( SBUF_LEN(&so->so_snd)
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293 | && tp->t_timer[TCPT_REXMT] == 0
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294 | && tp->t_timer[TCPT_PERSIST] == 0)
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295 | {
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296 | tp->t_rxtshift = 0;
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297 | tcp_setpersist(tp);
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298 | }
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299 |
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300 | /*
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301 | * No reason to send a segment, just return.
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302 | */
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303 | tcpstat.tcps_didnuttin++;
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304 |
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305 | LogFlowFuncLeave();
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306 | return (0);
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307 |
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308 | send:
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309 | LogFlowFunc(("send\n"));
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310 | /*
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311 | * Before ESTABLISHED, force sending of initial options
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312 | * unless TCP set not to do any options.
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313 | * NOTE: we assume that the IP/TCP header plus TCP options
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314 | * always fit in a single mbuf, leaving room for a maximum
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315 | * link header, i.e.
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316 | * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN
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317 | */
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318 | optlen = 0;
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319 | hdrlen = sizeof (struct tcpiphdr);
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320 | if (flags & TH_SYN)
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321 | {
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322 | tp->snd_nxt = tp->iss;
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323 | if ((tp->t_flags & TF_NOOPT) == 0)
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324 | {
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325 | u_int16_t mss;
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326 |
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327 | opt[0] = TCPOPT_MAXSEG;
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328 | opt[1] = 4;
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329 | mss = RT_H2N_U16((u_int16_t) tcp_mss(pData, tp, 0));
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330 | memcpy((caddr_t)(opt + 2), (caddr_t)&mss, sizeof(mss));
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331 | optlen = 4;
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332 |
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333 | #if 0
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334 | if ( (tp->t_flags & TF_REQ_SCALE)
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335 | && ( (flags & TH_ACK) == 0
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336 | || (tp->t_flags & TF_RCVD_SCALE)))
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337 | {
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338 | *((u_int32_t *) (opt + optlen)) = RT_H2N_U32( TCPOPT_NOP << 24
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339 | | TCPOPT_WINDOW << 16
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340 | | TCPOLEN_WINDOW << 8
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341 | | tp->request_r_scale);
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342 | optlen += 4;
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343 | }
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344 | #endif
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345 | }
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346 | }
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347 |
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348 | /*
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349 | * Send a timestamp and echo-reply if this is a SYN and our side
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350 | * wants to use timestamps (TF_REQ_TSTMP is set) or both our side
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351 | * and our peer have sent timestamps in our SYN's.
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352 | */
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353 | #if 0
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354 | if ( (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP
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355 | && (flags & TH_RST) == 0
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356 | && ( (flags & (TH_SYN|TH_ACK)) == TH_SYN
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357 | || (tp->t_flags & TF_RCVD_TSTMP)))
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358 | {
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359 | u_int32_t *lp = (u_int32_t *)(opt + optlen);
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360 |
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361 | /* Form timestamp option as shown in appendix A of RFC 1323. */
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362 | *lp++ = RT_H2N_U32_C(TCPOPT_TSTAMP_HDR);
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363 | *lp++ = RT_H2N_U32(tcp_now);
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364 | *lp = RT_H2N_U32(tp->ts_recent);
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365 | optlen += TCPOLEN_TSTAMP_APPA;
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366 | }
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367 | #endif
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368 | hdrlen += optlen;
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369 |
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370 | /*
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371 | * Adjust data length if insertion of options will
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372 | * bump the packet length beyond the t_maxseg length.
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373 | */
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374 | if (len > tp->t_maxseg - optlen)
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375 | {
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376 | len = tp->t_maxseg - optlen;
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377 | sendalot = 1;
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378 | }
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379 |
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380 | /*
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381 | * Grab a header mbuf, attaching a copy of data to
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382 | * be transmitted, and initialize the header from
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383 | * the template for sends on this connection.
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384 | */
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385 | if (len)
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386 | {
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387 | if (tp->t_force && len == 1)
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388 | tcpstat.tcps_sndprobe++;
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389 | else if (SEQ_LT(tp->snd_nxt, tp->snd_max))
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390 | {
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391 | tcpstat.tcps_sndrexmitpack++;
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392 | tcpstat.tcps_sndrexmitbyte += len;
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393 | }
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394 | else
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395 | {
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396 | tcpstat.tcps_sndpack++;
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397 | tcpstat.tcps_sndbyte += len;
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398 | }
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399 |
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400 | size = MCLBYTES;
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401 | if ((len + hdrlen + ETH_HLEN) < MSIZE)
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402 | size = MCLBYTES;
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403 | else if ((len + hdrlen + ETH_HLEN) < MCLBYTES)
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404 | size = MCLBYTES;
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405 | else if((len + hdrlen + ETH_HLEN) < MJUM9BYTES)
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406 | size = MJUM9BYTES;
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407 | else if ((len + hdrlen + ETH_HLEN) < MJUM16BYTES)
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408 | size = MJUM16BYTES;
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409 | else
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410 | AssertMsgFailed(("Unsupported size"));
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411 | m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
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412 | if (m == NULL)
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413 | {
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414 | /* error = ENOBUFS; */
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415 | error = 1;
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416 | goto out;
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417 | }
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418 | m->m_data += if_maxlinkhdr;
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419 | m->m_pkthdr.header = mtod(m, void *);
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420 | m->m_len = hdrlen;
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421 |
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422 | /*
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423 | * This will always succeed, since we make sure our mbufs
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424 | * are big enough to hold one MSS packet + header + ... etc.
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425 | */
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426 | #if 0
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427 | if (len <= MHLEN - hdrlen - max_linkhdr)
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428 | {
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429 | #endif
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430 | sbcopy(&so->so_snd, off, (int) len, mtod(m, caddr_t) + hdrlen);
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431 | m->m_len += len;
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432 | #if 0
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433 | }
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434 | else
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435 | {
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436 | m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len);
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437 | if (m->m_next == 0)
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438 | len = 0;
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439 | }
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440 | #endif
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441 | /*
|
---|
442 | * If we're sending everything we've got, set PUSH.
|
---|
443 | * (This will keep happy those implementations which only
|
---|
444 | * give data to the user when a buffer fills or
|
---|
445 | * a PUSH comes in.)
|
---|
446 | */
|
---|
447 | if (off + len == (ssize_t)SBUF_LEN(&so->so_snd))
|
---|
448 | flags |= TH_PUSH;
|
---|
449 | }
|
---|
450 | else
|
---|
451 | {
|
---|
452 | bool fUninitializedTemplate = false;
|
---|
453 | if (tp->t_flags & TF_ACKNOW)
|
---|
454 | tcpstat.tcps_sndacks++;
|
---|
455 | else if (flags & (TH_SYN|TH_FIN|TH_RST))
|
---|
456 | tcpstat.tcps_sndctrl++;
|
---|
457 | else if (SEQ_GT(tp->snd_up, tp->snd_una))
|
---|
458 | tcpstat.tcps_sndurg++;
|
---|
459 | else
|
---|
460 | tcpstat.tcps_sndwinup++;
|
---|
461 |
|
---|
462 | if ((hdrlen + ETH_HLEN) < MSIZE)
|
---|
463 | {
|
---|
464 | size = MCLBYTES;
|
---|
465 | }
|
---|
466 | else if ((hdrlen + ETH_HLEN) < MCLBYTES)
|
---|
467 | {
|
---|
468 | size = MCLBYTES;
|
---|
469 | }
|
---|
470 | else if((hdrlen + ETH_HLEN) < MJUM9BYTES)
|
---|
471 | {
|
---|
472 | size = MJUM9BYTES;
|
---|
473 | }
|
---|
474 | else if ((hdrlen + ETH_HLEN) < MJUM16BYTES)
|
---|
475 | {
|
---|
476 | size = MJUM16BYTES;
|
---|
477 | }
|
---|
478 | else
|
---|
479 | {
|
---|
480 | AssertMsgFailed(("Unsupported size"));
|
---|
481 | }
|
---|
482 | m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
|
---|
483 | if (m == NULL)
|
---|
484 | {
|
---|
485 | /* error = ENOBUFS; */
|
---|
486 | error = 1;
|
---|
487 | goto out;
|
---|
488 | }
|
---|
489 | m->m_data += if_maxlinkhdr;
|
---|
490 | m->m_pkthdr.header = mtod(m, void *);
|
---|
491 | m->m_len = hdrlen;
|
---|
492 | /*
|
---|
493 | * Uninitialized TCP template looks very suspicious at this processing state, thus why we have
|
---|
494 | * to workaround the problem till right fix. Warning appears once at release log.
|
---|
495 | */
|
---|
496 | fUninitializedTemplate = RT_BOOL(( tp->t_template.ti_src.s_addr == INADDR_ANY
|
---|
497 | || tp->t_template.ti_dst.s_addr == INADDR_ANY));
|
---|
498 | #ifndef DEBUG_vvl
|
---|
499 | if (fUninitializedTemplate)
|
---|
500 | {
|
---|
501 | static bool fWarn;
|
---|
502 | tcp_template(tp);
|
---|
503 | if(!fWarn)
|
---|
504 | {
|
---|
505 | LogRel(("NAT: TCP: TCP template was created forcely from socket information\n"));
|
---|
506 | fWarn = true;
|
---|
507 | }
|
---|
508 | }
|
---|
509 | #else
|
---|
510 | Assert((!fUninitializedTemplate));
|
---|
511 | #endif
|
---|
512 | }
|
---|
513 |
|
---|
514 | ti = mtod(m, struct tcpiphdr *);
|
---|
515 |
|
---|
516 | memcpy((caddr_t)ti, &tp->t_template, sizeof (struct tcpiphdr));
|
---|
517 |
|
---|
518 | /*
|
---|
519 | * Fill in fields, remembering maximum advertised
|
---|
520 | * window for use in delaying messages about window sizes.
|
---|
521 | * If resending a FIN, be sure not to use a new sequence number.
|
---|
522 | */
|
---|
523 | if ( flags & TH_FIN
|
---|
524 | && tp->t_flags & TF_SENTFIN
|
---|
525 | && tp->snd_nxt == tp->snd_max)
|
---|
526 | tp->snd_nxt--;
|
---|
527 | /*
|
---|
528 | * If we are doing retransmissions, then snd_nxt will
|
---|
529 | * not reflect the first unsent octet. For ACK only
|
---|
530 | * packets, we do not want the sequence number of the
|
---|
531 | * retransmitted packet, we want the sequence number
|
---|
532 | * of the next unsent octet. So, if there is no data
|
---|
533 | * (and no SYN or FIN), use snd_max instead of snd_nxt
|
---|
534 | * when filling in ti_seq. But if we are in persist
|
---|
535 | * state, snd_max might reflect one byte beyond the
|
---|
536 | * right edge of the window, so use snd_nxt in that
|
---|
537 | * case, since we know we aren't doing a retransmission.
|
---|
538 | * (retransmit and persist are mutually exclusive...)
|
---|
539 | */
|
---|
540 | if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
|
---|
541 | ti->ti_seq = RT_H2N_U32(tp->snd_nxt);
|
---|
542 | else
|
---|
543 | ti->ti_seq = RT_H2N_U32(tp->snd_max);
|
---|
544 | ti->ti_ack = RT_H2N_U32(tp->rcv_nxt);
|
---|
545 | if (optlen)
|
---|
546 | {
|
---|
547 | memcpy((caddr_t)(ti + 1), (caddr_t)opt, optlen);
|
---|
548 | ti->ti_off = (uint8_t)((sizeof (struct tcphdr) + optlen) >> 2);
|
---|
549 | }
|
---|
550 | ti->ti_flags = flags;
|
---|
551 | /*
|
---|
552 | * Calculate receive window. Don't shrink window,
|
---|
553 | * but avoid silly window syndrome.
|
---|
554 | */
|
---|
555 | if (win < (long)(SBUF_SIZE(&so->so_rcv) / 4) && win < (long)tp->t_maxseg)
|
---|
556 | win = 0;
|
---|
557 | if (win > (long)TCP_MAXWIN << tp->rcv_scale)
|
---|
558 | win = (long)TCP_MAXWIN << tp->rcv_scale;
|
---|
559 | if (win < (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt))
|
---|
560 | win = (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt);
|
---|
561 | ti->ti_win = RT_H2N_U16((u_int16_t) (win>>tp->rcv_scale));
|
---|
562 |
|
---|
563 | #if 0
|
---|
564 | if (SEQ_GT(tp->snd_up, tp->snd_nxt))
|
---|
565 | {
|
---|
566 | ti->ti_urp = RT_H2N_U16((u_int16_t)(tp->snd_up - tp->snd_nxt));
|
---|
567 | #else
|
---|
568 | if (SEQ_GT(tp->snd_up, tp->snd_una))
|
---|
569 | {
|
---|
570 | ti->ti_urp = RT_H2N_U16((u_int16_t)(tp->snd_up - RT_N2H_U32(ti->ti_seq)));
|
---|
571 | #endif
|
---|
572 | ti->ti_flags |= TH_URG;
|
---|
573 | }
|
---|
574 | else
|
---|
575 | /*
|
---|
576 | * If no urgent pointer to send, then we pull
|
---|
577 | * the urgent pointer to the left edge of the send window
|
---|
578 | * so that it doesn't drift into the send window on sequence
|
---|
579 | * number wraparound.
|
---|
580 | */
|
---|
581 | tp->snd_up = tp->snd_una; /* drag it along */
|
---|
582 |
|
---|
583 | /*
|
---|
584 | * Put TCP length in extended header, and then
|
---|
585 | * checksum extended header and data.
|
---|
586 | */
|
---|
587 | if (len + optlen)
|
---|
588 | ti->ti_len = RT_H2N_U16((u_int16_t)(sizeof (struct tcphdr)
|
---|
589 | + optlen + len));
|
---|
590 | ti->ti_sum = cksum(m, (int)(hdrlen + len));
|
---|
591 |
|
---|
592 | /*
|
---|
593 | * In transmit state, time the transmission and arrange for
|
---|
594 | * the retransmit. In persist state, just set snd_max.
|
---|
595 | */
|
---|
596 | if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0)
|
---|
597 | {
|
---|
598 | tcp_seq startseq = tp->snd_nxt;
|
---|
599 |
|
---|
600 | /*
|
---|
601 | * Advance snd_nxt over sequence space of this segment.
|
---|
602 | */
|
---|
603 | if (flags & (TH_SYN|TH_FIN))
|
---|
604 | {
|
---|
605 | if (flags & TH_SYN)
|
---|
606 | tp->snd_nxt++;
|
---|
607 | if (flags & TH_FIN)
|
---|
608 | {
|
---|
609 | tp->snd_nxt++;
|
---|
610 | tp->t_flags |= TF_SENTFIN;
|
---|
611 | }
|
---|
612 | }
|
---|
613 | tp->snd_nxt += len;
|
---|
614 | if (SEQ_GT(tp->snd_nxt, tp->snd_max))
|
---|
615 | {
|
---|
616 | tp->snd_max = tp->snd_nxt;
|
---|
617 | /*
|
---|
618 | * Time this transmission if not a retransmission and
|
---|
619 | * not currently timing anything.
|
---|
620 | */
|
---|
621 | if (tp->t_rtt == 0)
|
---|
622 | {
|
---|
623 | tp->t_rtt = 1;
|
---|
624 | tp->t_rtseq = startseq;
|
---|
625 | tcpstat.tcps_segstimed++;
|
---|
626 | }
|
---|
627 | }
|
---|
628 |
|
---|
629 | /*
|
---|
630 | * Set retransmit timer if not currently set,
|
---|
631 | * and not doing an ack or a keep-alive probe.
|
---|
632 | * Initial value for retransmit timer is smoothed
|
---|
633 | * round-trip time + 2 * round-trip time variance.
|
---|
634 | * Initialize shift counter which is used for backoff
|
---|
635 | * of retransmit time.
|
---|
636 | */
|
---|
637 | if ( tp->t_timer[TCPT_REXMT] == 0
|
---|
638 | && tp->snd_nxt != tp->snd_una)
|
---|
639 | {
|
---|
640 | tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
|
---|
641 | if (tp->t_timer[TCPT_PERSIST])
|
---|
642 | {
|
---|
643 | tp->t_timer[TCPT_PERSIST] = 0;
|
---|
644 | tp->t_rxtshift = 0;
|
---|
645 | }
|
---|
646 | }
|
---|
647 | }
|
---|
648 | else
|
---|
649 | if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
|
---|
650 | tp->snd_max = tp->snd_nxt + len;
|
---|
651 |
|
---|
652 | /*
|
---|
653 | * Fill in IP length and desired time to live and
|
---|
654 | * send to IP level. There should be a better way
|
---|
655 | * to handle ttl and tos; we could keep them in
|
---|
656 | * the template, but need a way to checksum without them.
|
---|
657 | */
|
---|
658 | M_ASSERTPKTHDR(m);
|
---|
659 | m->m_pkthdr.header = mtod(m, void *);
|
---|
660 | m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */
|
---|
661 |
|
---|
662 | {
|
---|
663 | ((struct ip *)ti)->ip_len = m->m_len;
|
---|
664 | ((struct ip *)ti)->ip_ttl = ip_defttl;
|
---|
665 | ((struct ip *)ti)->ip_tos = so->so_iptos;
|
---|
666 |
|
---|
667 | /* #if BSD >= 43 */
|
---|
668 | /* Don't do IP options... */
|
---|
669 | #if 0
|
---|
670 | error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
|
---|
671 | so->so_options & SO_DONTROUTE, 0);
|
---|
672 | #endif
|
---|
673 | error = ip_output(pData, so, m);
|
---|
674 |
|
---|
675 | #if 0
|
---|
676 | /* #else */
|
---|
677 | error = ip_output(m, (struct mbuf *)0, &tp->t_inpcb->inp_route,
|
---|
678 | so->so_options & SO_DONTROUTE);
|
---|
679 | /* #endif */
|
---|
680 | #endif
|
---|
681 | }
|
---|
682 | if (error)
|
---|
683 | {
|
---|
684 | out:
|
---|
685 | #if 0
|
---|
686 | if (error == ENOBUFS)
|
---|
687 | {
|
---|
688 | tcp_quench(tp->t_inpcb, 0);
|
---|
689 | return (0);
|
---|
690 | }
|
---|
691 |
|
---|
692 | if ( ( error == EHOSTUNREACH
|
---|
693 | || error == ENETDOWN)
|
---|
694 | && TCPS_HAVERCVDSYN(tp->t_state))
|
---|
695 | {
|
---|
696 | tp->t_softerror = error;
|
---|
697 | return (0);
|
---|
698 | }
|
---|
699 | #endif
|
---|
700 | if (m != NULL)
|
---|
701 | m_freem(pData, m);
|
---|
702 | return (error);
|
---|
703 | }
|
---|
704 | tcpstat.tcps_sndtotal++;
|
---|
705 |
|
---|
706 | /*
|
---|
707 | * Data sent (as far as we can tell).
|
---|
708 | * If this advertises a larger window than any other segment,
|
---|
709 | * then remember the size of the advertised window.
|
---|
710 | * Any pending ACK has now been sent.
|
---|
711 | */
|
---|
712 | if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
|
---|
713 | tp->rcv_adv = tp->rcv_nxt + win;
|
---|
714 | tp->last_ack_sent = tp->rcv_nxt;
|
---|
715 | tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
|
---|
716 | if (sendalot)
|
---|
717 | goto again;
|
---|
718 |
|
---|
719 | return (0);
|
---|
720 | }
|
---|
721 |
|
---|
722 | void
|
---|
723 | tcp_setpersist(struct tcpcb *tp)
|
---|
724 | {
|
---|
725 | int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
|
---|
726 |
|
---|
727 | #if 0
|
---|
728 | if (tp->t_timer[TCPT_REXMT])
|
---|
729 | panic("tcp_output REXMT");
|
---|
730 | #endif
|
---|
731 | /*
|
---|
732 | * Start/restart persistence timer.
|
---|
733 | */
|
---|
734 | TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
|
---|
735 | t * tcp_backoff[tp->t_rxtshift],
|
---|
736 | TCPTV_PERSMIN, TCPTV_PERSMAX);
|
---|
737 | if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
|
---|
738 | tp->t_rxtshift++;
|
---|
739 | }
|
---|