1/* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Definitions for the TCP protocol. 7 * 8 * Version: @(#)tcp.h 1.0.2 04/28/93 9 * 10 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17#ifndef _LINUX_TCP_H 18#define _LINUX_TCP_H 19 20#include <linux/types.h> 21#include <asm/byteorder.h> 22#include <linux/socket.h> 23 24struct tcphdr { 25 __be16 source; 26 __be16 dest; 27 __be32 seq; 28 __be32 ack_seq; 29#if defined(__LITTLE_ENDIAN_BITFIELD) 30 __u16 res1:4, 31 doff:4, 32 fin:1, 33 syn:1, 34 rst:1, 35 psh:1, 36 ack:1, 37 urg:1, 38 ece:1, 39 cwr:1; 40#elif defined(__BIG_ENDIAN_BITFIELD) 41 __u16 doff:4, 42 res1:4, 43 cwr:1, 44 ece:1, 45 urg:1, 46 ack:1, 47 psh:1, 48 rst:1, 49 syn:1, 50 fin:1; 51#else 52#error "Adjust your <asm/byteorder.h> defines" 53#endif 54 __be16 window; 55 __sum16 check; 56 __be16 urg_ptr; 57}; 58 59/* 60 * The union cast uses a gcc extension to avoid aliasing problems 61 * (union is compatible to any of its members) 62 * This means this part of the code is -fstrict-aliasing safe now. 63 */ 64union tcp_word_hdr { 65 struct tcphdr hdr; 66 __be32 words[5]; 67}; 68 69#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 70 71enum { 72 TCP_FLAG_CWR = __cpu_to_be32(0x00800000), 73 TCP_FLAG_ECE = __cpu_to_be32(0x00400000), 74 TCP_FLAG_URG = __cpu_to_be32(0x00200000), 75 TCP_FLAG_ACK = __cpu_to_be32(0x00100000), 76 TCP_FLAG_PSH = __cpu_to_be32(0x00080000), 77 TCP_FLAG_RST = __cpu_to_be32(0x00040000), 78 TCP_FLAG_SYN = __cpu_to_be32(0x00020000), 79 TCP_FLAG_FIN = __cpu_to_be32(0x00010000), 80 TCP_RESERVED_BITS = __cpu_to_be32(0x0F000000), 81 TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000) 82}; 83 84/* 85 * TCP general constants 86 */ 87#define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */ 88#define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */ 89 90/* TCP socket options */ 91#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */ 92#define TCP_MAXSEG 2 /* Limit MSS */ 93#define TCP_CORK 3 /* Never send partially complete segments */ 94#define TCP_KEEPIDLE 4 /* Start keeplives after this period */ 95#define TCP_KEEPINTVL 5 /* Interval between keepalives */ 96#define TCP_KEEPCNT 6 /* Number of keepalives before death */ 97#define TCP_SYNCNT 7 /* Number of SYN retransmits */ 98#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */ 99#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */ 100#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */ 101#define TCP_INFO 11 /* Information about this connection. */ 102#define TCP_QUICKACK 12 /* Block/reenable quick acks */ 103#define TCP_CONGESTION 13 /* Congestion control algorithm */ 104#define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ 105#define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */ 106#define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ 107#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ 108#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */ 109 110/* for TCP_INFO socket option */ 111#define TCPI_OPT_TIMESTAMPS 1 112#define TCPI_OPT_SACK 2 113#define TCPI_OPT_WSCALE 4 114#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */ 115#define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */ 116 117enum tcp_ca_state { 118 TCP_CA_Open = 0, 119#define TCPF_CA_Open (1<<TCP_CA_Open) 120 TCP_CA_Disorder = 1, 121#define TCPF_CA_Disorder (1<<TCP_CA_Disorder) 122 TCP_CA_CWR = 2, 123#define TCPF_CA_CWR (1<<TCP_CA_CWR) 124 TCP_CA_Recovery = 3, 125#define TCPF_CA_Recovery (1<<TCP_CA_Recovery) 126 TCP_CA_Loss = 4 127#define TCPF_CA_Loss (1<<TCP_CA_Loss) 128}; 129 130struct tcp_info { 131 __u8 tcpi_state; 132 __u8 tcpi_ca_state; 133 __u8 tcpi_retransmits; 134 __u8 tcpi_probes; 135 __u8 tcpi_backoff; 136 __u8 tcpi_options; 137 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4; 138 139 __u32 tcpi_rto; 140 __u32 tcpi_ato; 141 __u32 tcpi_snd_mss; 142 __u32 tcpi_rcv_mss; 143 144 __u32 tcpi_unacked; 145 __u32 tcpi_sacked; 146 __u32 tcpi_lost; 147 __u32 tcpi_retrans; 148 __u32 tcpi_fackets; 149 150 /* Times. */ 151 __u32 tcpi_last_data_sent; 152 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */ 153 __u32 tcpi_last_data_recv; 154 __u32 tcpi_last_ack_recv; 155 156 /* Metrics. */ 157 __u32 tcpi_pmtu; 158 __u32 tcpi_rcv_ssthresh; 159 __u32 tcpi_rtt; 160 __u32 tcpi_rttvar; 161 __u32 tcpi_snd_ssthresh; 162 __u32 tcpi_snd_cwnd; 163 __u32 tcpi_advmss; 164 __u32 tcpi_reordering; 165 166 __u32 tcpi_rcv_rtt; 167 __u32 tcpi_rcv_space; 168 169 __u32 tcpi_total_retrans; 170}; 171 172/* for TCP_MD5SIG socket option */ 173#define TCP_MD5SIG_MAXKEYLEN 80 174 175struct tcp_md5sig { 176 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ 177 __u16 __tcpm_pad1; /* zero */ 178 __u16 tcpm_keylen; /* key length */ 179 __u32 __tcpm_pad2; /* zero */ 180 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ 181}; 182 183/* for TCP_COOKIE_TRANSACTIONS (TCPCT) socket option */ 184#define TCP_COOKIE_MIN 8 /* 64-bits */ 185#define TCP_COOKIE_MAX 16 /* 128-bits */ 186#define TCP_COOKIE_PAIR_SIZE (2*TCP_COOKIE_MAX) 187 188/* Flags for both getsockopt and setsockopt */ 189#define TCP_COOKIE_IN_ALWAYS (1 << 0) /* Discard SYN without cookie */ 190#define TCP_COOKIE_OUT_NEVER (1 << 1) /* Prohibit outgoing cookies, 191 * supercedes everything. */ 192 193/* Flags for getsockopt */ 194#define TCP_S_DATA_IN (1 << 2) /* Was data received? */ 195#define TCP_S_DATA_OUT (1 << 3) /* Was data sent? */ 196 197/* TCP_COOKIE_TRANSACTIONS data */ 198struct tcp_cookie_transactions { 199 __u16 tcpct_flags; /* see above */ 200 __u8 __tcpct_pad1; /* zero */ 201 __u8 tcpct_cookie_desired; /* bytes */ 202 __u16 tcpct_s_data_desired; /* bytes of variable data */ 203 __u16 tcpct_used; /* bytes in value */ 204 __u8 tcpct_value[TCP_MSS_DEFAULT]; 205}; 206 207 208#endif /* _LINUX_TCP_H */ 209