1 | /*- |
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2 | * Copyright (c) 1982, 1986, 1993 |
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3 | * The Regents of the University of California. All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * 1. Redistributions of source code must retain the above copyright |
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9 | * notice, this list of conditions and the following disclaimer. |
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10 | * 2. Redistributions in binary form must reproduce the above copyright |
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11 | * notice, this list of conditions and the following disclaimer in the |
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12 | * documentation and/or other materials provided with the distribution. |
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13 | * 4. Neither the name of the University nor the names of its contributors |
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14 | * may be used to endorse or promote products derived from this software |
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15 | * without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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27 | * SUCH DAMAGE. |
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28 | * |
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29 | * @(#)tcp.h 8.1 (Berkeley) 6/10/93 |
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30 | * $FreeBSD$ |
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31 | */ |
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32 | |
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33 | #ifndef _NETINET_TCP_H_ |
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34 | #define _NETINET_TCP_H_ |
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35 | |
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36 | #include <sys/cdefs.h> |
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37 | #include <sys/types.h> |
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38 | |
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39 | #if __BSD_VISIBLE |
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40 | |
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41 | typedef u_int32_t tcp_seq; |
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42 | |
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43 | #define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ |
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44 | #define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ |
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45 | |
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46 | /* |
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47 | * TCP header. |
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48 | * Per RFC 793, September, 1981. |
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49 | */ |
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50 | struct tcphdr { |
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51 | u_short th_sport; /* source port */ |
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52 | u_short th_dport; /* destination port */ |
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53 | tcp_seq th_seq; /* sequence number */ |
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54 | tcp_seq th_ack; /* acknowledgement number */ |
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55 | #if BYTE_ORDER == LITTLE_ENDIAN |
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56 | u_char th_x2:4, /* (unused) */ |
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57 | th_off:4; /* data offset */ |
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58 | #endif |
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59 | #if BYTE_ORDER == BIG_ENDIAN |
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60 | u_char th_off:4, /* data offset */ |
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61 | th_x2:4; /* (unused) */ |
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62 | #endif |
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63 | u_char th_flags; |
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64 | #define TH_FIN 0x01 |
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65 | #define TH_SYN 0x02 |
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66 | #define TH_RST 0x04 |
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67 | #define TH_PUSH 0x08 |
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68 | #define TH_ACK 0x10 |
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69 | #define TH_URG 0x20 |
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70 | #define TH_ECE 0x40 |
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71 | #define TH_CWR 0x80 |
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72 | #define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) |
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73 | #define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR" |
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74 | |
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75 | u_short th_win; /* window */ |
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76 | u_short th_sum; /* checksum */ |
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77 | u_short th_urp; /* urgent pointer */ |
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78 | }; |
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79 | |
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80 | #define TCPOPT_EOL 0 |
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81 | #define TCPOLEN_EOL 1 |
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82 | #define TCPOPT_PAD 0 /* padding after EOL */ |
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83 | #define TCPOLEN_PAD 1 |
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84 | #define TCPOPT_NOP 1 |
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85 | #define TCPOLEN_NOP 1 |
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86 | #define TCPOPT_MAXSEG 2 |
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87 | #define TCPOLEN_MAXSEG 4 |
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88 | #define TCPOPT_WINDOW 3 |
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89 | #define TCPOLEN_WINDOW 3 |
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90 | #define TCPOPT_SACK_PERMITTED 4 |
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91 | #define TCPOLEN_SACK_PERMITTED 2 |
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92 | #define TCPOPT_SACK 5 |
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93 | #define TCPOLEN_SACKHDR 2 |
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94 | #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ |
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95 | #define TCPOPT_TIMESTAMP 8 |
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96 | #define TCPOLEN_TIMESTAMP 10 |
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97 | #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ |
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98 | #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ |
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99 | #define TCPOLEN_SIGNATURE 18 |
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100 | |
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101 | /* Miscellaneous constants */ |
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102 | #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ |
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103 | #define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ |
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104 | |
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105 | |
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106 | /* |
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107 | * The default maximum segment size (MSS) to be used for new TCP connections |
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108 | * when path MTU discovery is not enabled. |
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109 | * |
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110 | * RFC879 derives the default MSS from the largest datagram size hosts are |
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111 | * minimally required to handle directly or through IP reassembly minus the |
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112 | * size of the IP and TCP header. With IPv6 the minimum MTU is specified |
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113 | * in RFC2460. |
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114 | * |
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115 | * For IPv4 the MSS is 576 - sizeof(struct tcpiphdr) |
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116 | * For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr) |
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117 | * |
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118 | * We use explicit numerical definition here to avoid header pollution. |
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119 | */ |
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120 | #define TCP_MSS 536 |
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121 | #define TCP6_MSS 1220 |
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122 | |
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123 | /* |
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124 | * Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS |
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125 | * option. Allowing low values of MSS can consume significant resources and |
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126 | * be used to mount a resource exhaustion attack. |
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127 | * Connections requesting lower MSS values will be rounded up to this value |
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128 | * and the IP_DF flag will be cleared to allow fragmentation along the path. |
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129 | * |
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130 | * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting |
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131 | * it to "0" disables the minmss check. |
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132 | * |
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133 | * The default value is fine for TCP across the Internet's smallest official |
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134 | * link MTU (256 bytes for AX.25 packet radio). However, a connection is very |
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135 | * unlikely to come across such low MTU interfaces these days (anno domini 2003). |
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136 | */ |
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137 | #define TCP_MINMSS 216 |
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138 | |
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139 | #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ |
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140 | #define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ |
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141 | |
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142 | #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ |
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143 | |
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144 | #define TCP_MAXBURST 4 /* maximum segments in a burst */ |
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145 | |
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146 | #define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ |
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147 | #define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) |
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148 | /* max space left for options */ |
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149 | #endif /* __BSD_VISIBLE */ |
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150 | |
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151 | /* |
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152 | * User-settable options (used with setsockopt). These are discrete |
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153 | * values and are not masked together. Some values appear to be |
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154 | * bitmasks for historical reasons. |
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155 | */ |
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156 | #define TCP_NODELAY 1 /* don't delay send to coalesce packets */ |
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157 | #if __BSD_VISIBLE |
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158 | #define TCP_MAXSEG 2 /* set maximum segment size */ |
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159 | #define TCP_NOPUSH 4 /* don't push last block of write */ |
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160 | #define TCP_NOOPT 8 /* don't use TCP options */ |
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161 | #define TCP_MD5SIG 16 /* use MD5 digests (RFC2385) */ |
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162 | #define TCP_INFO 32 /* retrieve tcp_info structure */ |
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163 | #define TCP_CONGESTION 64 /* get/set congestion control algorithm */ |
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164 | #define TCP_KEEPINIT 128 /* N, time to establish connection */ |
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165 | #define TCP_KEEPIDLE 256 /* L,N,X start keeplives after this period */ |
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166 | #define TCP_KEEPINTVL 512 /* L,N interval between keepalives */ |
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167 | #define TCP_KEEPCNT 1024 /* L,N number of keepalives before close */ |
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168 | |
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169 | /* Start of reserved space for third-party user-settable options. */ |
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170 | #define TCP_VENDOR SO_VENDOR |
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171 | |
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172 | #define TCP_CA_NAME_MAX 16 /* max congestion control name length */ |
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173 | |
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174 | #define TCPI_OPT_TIMESTAMPS 0x01 |
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175 | #define TCPI_OPT_SACK 0x02 |
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176 | #define TCPI_OPT_WSCALE 0x04 |
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177 | #define TCPI_OPT_ECN 0x08 |
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178 | #define TCPI_OPT_TOE 0x10 |
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179 | |
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180 | /* |
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181 | * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits |
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182 | * the caller to query certain information about the state of a TCP |
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183 | * connection. We provide an overlapping set of fields with the Linux |
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184 | * implementation, but since this is a fixed size structure, room has been |
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185 | * left for growth. In order to maximize potential future compatibility with |
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186 | * the Linux API, the same variable names and order have been adopted, and |
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187 | * padding left to make room for omitted fields in case they are added later. |
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188 | * |
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189 | * XXX: This is currently an unstable ABI/API, in that it is expected to |
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190 | * change. |
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191 | */ |
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192 | struct tcp_info { |
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193 | u_int8_t tcpi_state; /* TCP FSM state. */ |
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194 | u_int8_t __tcpi_ca_state; |
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195 | u_int8_t __tcpi_retransmits; |
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196 | u_int8_t __tcpi_probes; |
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197 | u_int8_t __tcpi_backoff; |
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198 | u_int8_t tcpi_options; /* Options enabled on conn. */ |
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199 | u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ |
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200 | tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ |
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201 | |
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202 | u_int32_t tcpi_rto; /* Retransmission timeout (usec). */ |
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203 | u_int32_t __tcpi_ato; |
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204 | u_int32_t tcpi_snd_mss; /* Max segment size for send. */ |
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205 | u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */ |
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206 | |
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207 | u_int32_t __tcpi_unacked; |
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208 | u_int32_t __tcpi_sacked; |
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209 | u_int32_t __tcpi_lost; |
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210 | u_int32_t __tcpi_retrans; |
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211 | u_int32_t __tcpi_fackets; |
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212 | |
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213 | /* Times; measurements in usecs. */ |
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214 | u_int32_t __tcpi_last_data_sent; |
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215 | u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ |
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216 | u_int32_t tcpi_last_data_recv; /* Time since last recv data. */ |
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217 | u_int32_t __tcpi_last_ack_recv; |
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218 | |
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219 | /* Metrics; variable units. */ |
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220 | u_int32_t __tcpi_pmtu; |
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221 | u_int32_t __tcpi_rcv_ssthresh; |
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222 | u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ |
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223 | u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ |
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224 | u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ |
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225 | u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ |
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226 | u_int32_t __tcpi_advmss; |
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227 | u_int32_t __tcpi_reordering; |
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228 | |
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229 | u_int32_t __tcpi_rcv_rtt; |
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230 | u_int32_t tcpi_rcv_space; /* Advertised recv window. */ |
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231 | |
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232 | /* FreeBSD extensions to tcp_info. */ |
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233 | u_int32_t tcpi_snd_wnd; /* Advertised send window. */ |
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234 | u_int32_t tcpi_snd_bwnd; /* No longer used. */ |
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235 | u_int32_t tcpi_snd_nxt; /* Next egress seqno */ |
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236 | u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */ |
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237 | u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ |
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238 | u_int32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ |
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239 | u_int32_t tcpi_rcv_ooopack; /* Out-of-order packets */ |
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240 | u_int32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ |
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241 | |
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242 | /* Padding to grow without breaking ABI. */ |
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243 | u_int32_t __tcpi_pad[26]; /* Padding. */ |
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244 | }; |
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245 | #endif |
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246 | |
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247 | #endif /* !_NETINET_TCP_H_ */ |
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