1 /* 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 34 */ 35 36 typedef u_long tcp_seq; 37 /* 38 * TCP header. 39 * Per RFC 793, September, 1981. 40 */ 41 struct tcphdr { 42 u_short th_sport; /* source port */ 43 u_short th_dport; /* destination port */ 44 tcp_seq th_seq; /* sequence number */ 45 tcp_seq th_ack; /* acknowledgement number */ 46 #if BYTE_ORDER == LITTLE_ENDIAN 47 u_char th_x2:4, /* (unused) */ 48 th_off:4; /* data offset */ 49 #endif 50 #if BYTE_ORDER == BIG_ENDIAN 51 u_char th_off:4, /* data offset */ 52 th_x2:4; /* (unused) */ 53 #endif 54 u_char th_flags; 55 #define TH_FIN 0x01 56 #define TH_SYN 0x02 57 #define TH_RST 0x04 58 #define TH_PUSH 0x08 59 #define TH_ACK 0x10 60 #define TH_URG 0x20 61 u_short th_win; /* window */ 62 u_short th_sum; /* checksum */ 63 u_short th_urp; /* urgent pointer */ 64 }; 65 66 #define TCPOPT_EOL 0 67 #define TCPOPT_NOP 1 68 #define TCPOPT_MAXSEG 2 69 #define TCPOLEN_MAXSEG 4 70 #define TCPOPT_WINDOW 3 71 #define TCPOLEN_WINDOW 3 72 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 73 #define TCPOLEN_SACK_PERMITTED 2 74 #define TCPOPT_SACK 5 /* Experimental */ 75 #define TCPOPT_TIMESTAMP 8 76 #define TCPOLEN_TIMESTAMP 10 77 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 78 79 #define TCPOPT_TSTAMP_HDR \ 80 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 81 82 /* 83 * Default maximum segment size for TCP. 84 * With an IP MSS of 576, this is 536, 85 * but 512 is probably more convenient. 86 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)). 87 */ 88 #define TCP_MSS 512 89 90 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 91 92 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 93 94 /* 95 * User-settable options (used with setsockopt). 96 */ 97 #define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 98 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 99