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 = __constant_cpu_to_be32(0x00800000), 73 TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000), 74 TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000), 75 TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000), 76 TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000), 77 TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000), 78 TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000), 79 TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000), 80 TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000), 81 TCP_DATA_OFFSET = __constant_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_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ 106#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ 107#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */ 108#define TCP_REPAIR 19 /* TCP sock is under repair right now */ 109#define TCP_REPAIR_QUEUE 20 110#define TCP_QUEUE_SEQ 21 111#define TCP_REPAIR_OPTIONS 22 112#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */ 113#define TCP_TIMESTAMP 24 114#define TCP_NOTSENT_LOWAT 25 /* limit number of unsent bytes in write queue */ 115#define TCP_CC_INFO 26 /* Get Congestion Control (optional) info */ 116#define TCP_SAVE_SYN 27 /* Record SYN headers for new connections */ 117#define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */ 118 119struct tcp_repair_opt { 120 __u32 opt_code; 121 __u32 opt_val; 122}; 123 124enum { 125 TCP_NO_QUEUE, 126 TCP_RECV_QUEUE, 127 TCP_SEND_QUEUE, 128 TCP_QUEUES_NR, 129}; 130 131/* for TCP_INFO socket option */ 132#define TCPI_OPT_TIMESTAMPS 1 133#define TCPI_OPT_SACK 2 134#define TCPI_OPT_WSCALE 4 135#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */ 136#define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */ 137#define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */ 138 139enum tcp_ca_state { 140 TCP_CA_Open = 0, 141#define TCPF_CA_Open (1<<TCP_CA_Open) 142 TCP_CA_Disorder = 1, 143#define TCPF_CA_Disorder (1<<TCP_CA_Disorder) 144 TCP_CA_CWR = 2, 145#define TCPF_CA_CWR (1<<TCP_CA_CWR) 146 TCP_CA_Recovery = 3, 147#define TCPF_CA_Recovery (1<<TCP_CA_Recovery) 148 TCP_CA_Loss = 4 149#define TCPF_CA_Loss (1<<TCP_CA_Loss) 150}; 151 152struct tcp_info { 153 __u8 tcpi_state; 154 __u8 tcpi_ca_state; 155 __u8 tcpi_retransmits; 156 __u8 tcpi_probes; 157 __u8 tcpi_backoff; 158 __u8 tcpi_options; 159 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4; 160 161 __u32 tcpi_rto; 162 __u32 tcpi_ato; 163 __u32 tcpi_snd_mss; 164 __u32 tcpi_rcv_mss; 165 166 __u32 tcpi_unacked; 167 __u32 tcpi_sacked; 168 __u32 tcpi_lost; 169 __u32 tcpi_retrans; 170 __u32 tcpi_fackets; 171 172 /* Times. */ 173 __u32 tcpi_last_data_sent; 174 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */ 175 __u32 tcpi_last_data_recv; 176 __u32 tcpi_last_ack_recv; 177 178 /* Metrics. */ 179 __u32 tcpi_pmtu; 180 __u32 tcpi_rcv_ssthresh; 181 __u32 tcpi_rtt; 182 __u32 tcpi_rttvar; 183 __u32 tcpi_snd_ssthresh; 184 __u32 tcpi_snd_cwnd; 185 __u32 tcpi_advmss; 186 __u32 tcpi_reordering; 187 188 __u32 tcpi_rcv_rtt; 189 __u32 tcpi_rcv_space; 190 191 __u32 tcpi_total_retrans; 192 193 __u64 tcpi_pacing_rate; 194 __u64 tcpi_max_pacing_rate; 195 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */ 196 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */ 197 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */ 198 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */ 199}; 200 201/* for TCP_MD5SIG socket option */ 202#define TCP_MD5SIG_MAXKEYLEN 80 203 204struct tcp_md5sig { 205 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ 206 __u16 __tcpm_pad1; /* zero */ 207 __u16 tcpm_keylen; /* key length */ 208 __u32 __tcpm_pad2; /* zero */ 209 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ 210}; 211 212#endif /* _LINUX_TCP_H */ 213