tcp.h revision 212765
1139823Simp/*- 21541Srgrimes * Copyright (c) 1982, 1986, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * Redistribution and use in source and binary forms, with or without 61541Srgrimes * modification, are permitted provided that the following conditions 71541Srgrimes * are met: 81541Srgrimes * 1. Redistributions of source code must retain the above copyright 91541Srgrimes * notice, this list of conditions and the following disclaimer. 101541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111541Srgrimes * notice, this list of conditions and the following disclaimer in the 121541Srgrimes * documentation and/or other materials provided with the distribution. 131541Srgrimes * 4. Neither the name of the University nor the names of its contributors 141541Srgrimes * may be used to endorse or promote products derived from this software 151541Srgrimes * without specific prior written permission. 161541Srgrimes * 171541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 191541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271541Srgrimes * SUCH DAMAGE. 281541Srgrimes * 291541Srgrimes * @(#)tcp.h 8.1 (Berkeley) 6/10/93 3050477Speter * $FreeBSD: head/sys/netinet/tcp.h 212765 2010-09-16 21:06:45Z andre $ 311541Srgrimes */ 321541Srgrimes 332169Spaul#ifndef _NETINET_TCP_H_ 342169Spaul#define _NETINET_TCP_H_ 352169Spaul 36104343Smike#include <sys/cdefs.h> 37104343Smike 38104342Smike#if __BSD_VISIBLE 39104342Smike 4037622Sbdetypedef u_int32_t tcp_seq; 416247Swollman 4255679Sshin#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ 4355679Sshin#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ 4455679Sshin 451541Srgrimes/* 461541Srgrimes * TCP header. 471541Srgrimes * Per RFC 793, September, 1981. 481541Srgrimes */ 491541Srgrimesstruct tcphdr { 501541Srgrimes u_short th_sport; /* source port */ 511541Srgrimes u_short th_dport; /* destination port */ 521541Srgrimes tcp_seq th_seq; /* sequence number */ 531541Srgrimes tcp_seq th_ack; /* acknowledgement number */ 548876Srgrimes#if BYTE_ORDER == LITTLE_ENDIAN 55203343Sluigi u_char th_x2:4, /* (unused) */ 561541Srgrimes th_off:4; /* data offset */ 571541Srgrimes#endif 588876Srgrimes#if BYTE_ORDER == BIG_ENDIAN 59203343Sluigi u_char th_off:4, /* data offset */ 601541Srgrimes th_x2:4; /* (unused) */ 611541Srgrimes#endif 621541Srgrimes u_char th_flags; 631541Srgrimes#define TH_FIN 0x01 641541Srgrimes#define TH_SYN 0x02 651541Srgrimes#define TH_RST 0x04 661541Srgrimes#define TH_PUSH 0x08 671541Srgrimes#define TH_ACK 0x10 681541Srgrimes#define TH_URG 0x20 6970826Srwatson#define TH_ECE 0x40 7070826Srwatson#define TH_CWR 0x80 71155817Sandre#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) 72169997Sandre#define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR" 736348Swollman 741541Srgrimes u_short th_win; /* window */ 751541Srgrimes u_short th_sum; /* checksum */ 761541Srgrimes u_short th_urp; /* urgent pointer */ 771541Srgrimes}; 781541Srgrimes 791541Srgrimes#define TCPOPT_EOL 0 80167606Sandre#define TCPOLEN_EOL 1 81177986Sandre#define TCPOPT_PAD 0 /* padding after EOL */ 82177986Sandre#define TCPOLEN_PAD 1 831541Srgrimes#define TCPOPT_NOP 1 84167606Sandre#define TCPOLEN_NOP 1 851541Srgrimes#define TCPOPT_MAXSEG 2 861541Srgrimes#define TCPOLEN_MAXSEG 4 871541Srgrimes#define TCPOPT_WINDOW 3 881541Srgrimes#define TCPOLEN_WINDOW 3 89167606Sandre#define TCPOPT_SACK_PERMITTED 4 901541Srgrimes#define TCPOLEN_SACK_PERMITTED 2 91167606Sandre#define TCPOPT_SACK 5 92167606Sandre#define TCPOLEN_SACKHDR 2 93130989Sps#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 941541Srgrimes#define TCPOPT_TIMESTAMP 8 951541Srgrimes#define TCPOLEN_TIMESTAMP 10 961541Srgrimes#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 97168904Sandre#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ 98125680Sbms#define TCPOLEN_SIGNATURE 18 996247Swollman 100130989Sps/* Miscellaneous constants */ 101149403Sps#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ 102146552Sps#define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ 103130989Sps 104130989Sps 1051541Srgrimes/* 106212653Sandre * The default maximum segment size (MSS) to be used for new TCP connections 107212653Sandre * when path MTU discovery is not enabled. 108212653Sandre * 109212653Sandre * RFC879 derives the default MSS from the largest datagram size hosts are 110212653Sandre * minimally required to handle directly or through IP reassembly minus the 111212653Sandre * size of the IP and TCP header. With IPv6 the minimum MTU is specified 112212653Sandre * in RFC2460. 113212653Sandre * 114212653Sandre * For IPv4 the MSS is 576 - sizeof(struct tcpiphdr) 115212653Sandre * For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr) 116212653Sandre * 117212653Sandre * We use explicit numerical definition here to avoid header pollution. 1181541Srgrimes */ 119212653Sandre#define TCP_MSS 536 120212653Sandre#define TCP6_MSS 1220 121212653Sandre 122124258Sandre/* 123212731Sandre * Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS 124212731Sandre * option. Allowing low values of MSS can consume significant resources and 125212731Sandre * be used to mount a resource exhaustion attack. 126212653Sandre * Connections requesting lower MSS values will be rounded up to this value 127212731Sandre * and the IP_DF flag will be cleared to allow fragmentation along the path. 128212653Sandre * 129212653Sandre * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting 130212653Sandre * it to "0" disables the minmss check. 131212653Sandre * 132212731Sandre * The default value is fine for TCP across the Internet's smallest official 133212731Sandre * link MTU (256 bytes for AX.25 packet radio). However, a connection is very 134212731Sandre * unlikely to come across such low MTU interfaces these days (anno domini 2003). 135124258Sandre */ 136124290Sandre#define TCP_MINMSS 216 1371541Srgrimes 1381541Srgrimes#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 1396247Swollman#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 1401541Srgrimes 1411541Srgrimes#define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 1421541Srgrimes 143133874Srwatson#define TCP_MAXBURST 4 /* maximum segments in a burst */ 14460067Sjlemon 1456247Swollman#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 1466247Swollman#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 1476247Swollman /* max space left for options */ 148104342Smike#endif /* __BSD_VISIBLE */ 1496247Swollman 1501541Srgrimes/* 1511541Srgrimes * User-settable options (used with setsockopt). 1521541Srgrimes */ 1531541Srgrimes#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 154104342Smike#if __BSD_VISIBLE 1551541Srgrimes#define TCP_MAXSEG 0x02 /* set maximum segment size */ 1566247Swollman#define TCP_NOPUSH 0x04 /* don't push last block of write */ 1576247Swollman#define TCP_NOOPT 0x08 /* don't use TCP options */ 158125890Sbms#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */ 159138118Srwatson#define TCP_INFO 0x20 /* retrieve tcp_info structure */ 160174636Skmacy#define TCP_CONGESTION 0x40 /* get/set congestion control algorithm */ 161138118Srwatson 162174636Skmacy#define TCP_CA_NAME_MAX 16 /* max congestion control name length */ 163174636Skmacy 164138118Srwatson#define TCPI_OPT_TIMESTAMPS 0x01 165138118Srwatson#define TCPI_OPT_SACK 0x02 166138118Srwatson#define TCPI_OPT_WSCALE 0x04 167138118Srwatson#define TCPI_OPT_ECN 0x08 168178793Skmacy#define TCPI_OPT_TOE 0x10 169138118Srwatson 170138118Srwatson/* 171138118Srwatson * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits 172138118Srwatson * the caller to query certain information about the state of a TCP 173138118Srwatson * connection. We provide an overlapping set of fields with the Linux 174138118Srwatson * implementation, but since this is a fixed size structure, room has been 175138118Srwatson * left for growth. In order to maximize potential future compatibility with 176138118Srwatson * the Linux API, the same variable names and order have been adopted, and 177138118Srwatson * padding left to make room for omitted fields in case they are added later. 178138118Srwatson * 179138118Srwatson * XXX: This is currently an unstable ABI/API, in that it is expected to 180138118Srwatson * change. 181138118Srwatson */ 182138118Srwatsonstruct tcp_info { 183138118Srwatson u_int8_t tcpi_state; /* TCP FSM state. */ 184138118Srwatson u_int8_t __tcpi_ca_state; 185138118Srwatson u_int8_t __tcpi_retransmits; 186138118Srwatson u_int8_t __tcpi_probes; 187138118Srwatson u_int8_t __tcpi_backoff; 188138118Srwatson u_int8_t tcpi_options; /* Options enabled on conn. */ 189138118Srwatson u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ 190138118Srwatson tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ 191138118Srwatson 192200847Sjhb u_int32_t tcpi_rto; /* Retransmission timeout (usec). */ 193138118Srwatson u_int32_t __tcpi_ato; 194200847Sjhb u_int32_t tcpi_snd_mss; /* Max segment size for send. */ 195200847Sjhb u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */ 196138118Srwatson 197138118Srwatson u_int32_t __tcpi_unacked; 198138118Srwatson u_int32_t __tcpi_sacked; 199138118Srwatson u_int32_t __tcpi_lost; 200138118Srwatson u_int32_t __tcpi_retrans; 201138118Srwatson u_int32_t __tcpi_fackets; 202138118Srwatson 203138118Srwatson /* Times; measurements in usecs. */ 204138118Srwatson u_int32_t __tcpi_last_data_sent; 205138118Srwatson u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ 206200847Sjhb u_int32_t tcpi_last_data_recv; /* Time since last recv data. */ 207138118Srwatson u_int32_t __tcpi_last_ack_recv; 208138118Srwatson 209138118Srwatson /* Metrics; variable units. */ 210138118Srwatson u_int32_t __tcpi_pmtu; 211138118Srwatson u_int32_t __tcpi_rcv_ssthresh; 212166433Sbms u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ 213166433Sbms u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ 214138118Srwatson u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ 215138118Srwatson u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ 216138118Srwatson u_int32_t __tcpi_advmss; 217138118Srwatson u_int32_t __tcpi_reordering; 218138118Srwatson 219138118Srwatson u_int32_t __tcpi_rcv_rtt; 220138136Srwatson u_int32_t tcpi_rcv_space; /* Advertised recv window. */ 221138118Srwatson 222138118Srwatson /* FreeBSD extensions to tcp_info. */ 223138118Srwatson u_int32_t tcpi_snd_wnd; /* Advertised send window. */ 224212765Sandre u_int32_t tcpi_snd_bwnd; /* No longer used. */ 225178793Skmacy u_int32_t tcpi_snd_nxt; /* Next egress seqno */ 226178793Skmacy u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */ 227178793Skmacy u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ 228178793Skmacy 229138118Srwatson /* Padding to grow without breaking ABI. */ 230178793Skmacy u_int32_t __tcpi_pad[29]; /* Padding. */ 231138118Srwatson}; 232104342Smike#endif 2332169Spaul 234104342Smike#endif /* !_NETINET_TCP_H_ */ 235