/* $NetBSD: tcp.h,v 1.38 2026/01/08 15:39:07 nia Exp $ */ /* * Copyright (c) 1982, 1986, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)tcp.h 8.1 (Berkeley) 6/10/93 */ #ifndef _NETINET_TCP_H_ #define _NETINET_TCP_H_ #include <sys/featuretest.h> #if defined(_NETBSD_SOURCE) #include <sys/types.h> #include <sys/endian.h> typedef uint32_t tcp_seq; /* * TCP header. * Per RFC 793, September, 1981. * Updated by RFC 3168, September, 2001. */ struct tcphdr { uint16_t th_sport; /* source port */ uint16_t th_dport; /* destination port */ tcp_seq th_seq; /* sequence number */ tcp_seq th_ack; /* acknowledgement number */ #if BYTE_ORDER == LITTLE_ENDIAN /*LINTED non-portable bitfields*/ uint8_t th_x2:4, /* (unused) */ th_off:4; /* data offset */ #endif #if BYTE_ORDER == BIG_ENDIAN /*LINTED non-portable bitfields*/ uint8_t th_off:4, /* data offset */ th_x2:4; /* (unused) */ #endif uint8_t th_flags; #define TH_FIN 0x01 /* Final: Set on the last segment */ #define TH_SYN 0x02 /* Synchronization: New conn with dst port */ #define TH_RST 0x04 /* Reset: Announce to peer conn terminated */ #define TH_PUSH 0x08 /* Push: Immediately send, don't buffer seg */ #define TH_ACK 0x10 /* Acknowledge: Part of connection establish */ #define TH_URG 0x20 /* Urgent: send special marked segment now */ #define TH_ECE 0x40 /* ECN Echo */ #define TH_CWR 0x80 /* Congestion Window Reduced */ uint16_t th_win; /* window */ uint16_t th_sum; /* checksum */ uint16_t th_urp; /* urgent pointer */ }; #ifdef __CTASSERT __CTASSERT(sizeof(struct tcphdr) == 20); #endif #define TCPOPT_EOL 0 #define TCPOLEN_EOL 1 #define TCPOPT_PAD 0 #define TCPOLEN_PAD 1 #define TCPOPT_NOP 1 #define TCPOLEN_NOP 1 #define TCPOPT_MAXSEG 2 #define TCPOLEN_MAXSEG 4 #define TCPOPT_WINDOW 3 #define TCPOLEN_WINDOW 3 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ #define TCPOLEN_SACK_PERMITTED 2 #define TCPOPT_SACK 5 /* Experimental */ #define TCPOPT_TIMESTAMP 8 #define TCPOLEN_TIMESTAMP 10 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ #define TCPOPT_TSTAMP_HDR \ (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ #define TCPOLEN_SIGNATURE 18 #define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */ #define MAX_TCPOPTLEN 40 /* max # bytes that go in options */ /* * Default maximum segment size for TCP. * This is defined by RFC 1112 Sec 4.2.2.6. */ #define TCP_MSS 536 #define TCP_MINMSS 216 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ #define TCP_MAXBURST 4 /* maximum segments in a burst */ #endif /* _NETBSD_SOURCE */ /* * User-settable options (used with setsockopt). */ #define TCP_NODELAY 1 /* don't delay send to coalesce packets */ #define TCP_MAXSEG 2 /* set maximum segment size */ #define TCP_KEEPIDLE 3 #ifdef notyet #define TCP_NOPUSH 4 /* reserved for FreeBSD compat */ #endif #define TCP_KEEPINTVL 5 #define TCP_KEEPCNT 6 #define TCP_KEEPINIT 7 #ifdef notyet #define TCP_NOOPT 8 /* reserved for FreeBSD compat */ #endif #define TCP_INFO 9 /* retrieve tcp_info structure */ #define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */ #define TCP_CONGCTL 0x20 /* selected congestion control */ #define TCPI_OPT_TIMESTAMPS 0x01 #define TCPI_OPT_SACK 0x02 #define TCPI_OPT_WSCALE 0x04 #define TCPI_OPT_ECN 0x08 #define TCPI_OPT_TOE 0x10 /* * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits * the caller to query certain information about the state of a TCP * connection. We provide an overlapping set of fields with the Linux * implementation, but since this is a fixed size structure, room has been * left for growth. In order to maximize potential future compatibility with * the Linux API, the same variable names and order have been adopted, and * padding left to make room for omitted fields in case they are added later. * * XXX: This is currently an unstable ABI/API, in that it is expected to * change. */ struct tcp_info { uint8_t tcpi_state; /* TCP FSM state. */ uint8_t __tcpi_ca_state; uint8_t __tcpi_retransmits; uint8_t __tcpi_probes; uint8_t __tcpi_backoff; uint8_t tcpi_options; /* Options enabled on conn. */ /*LINTED: non-portable bitfield*/ uint8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ /*LINTED: non-portable bitfield*/ tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ uint32_t tcpi_rto; /* Retransmission timeout (usec). */ uint32_t __tcpi_ato; uint32_t tcpi_snd_mss; /* Max segment size for send. */ uint32_t tcpi_rcv_mss; /* Max segment size for receive. */ uint32_t __tcpi_unacked; uint32_t __tcpi_sacked; uint32_t __tcpi_lost; uint32_t __tcpi_retrans; uint32_t __tcpi_fackets; /* Times; measurements in usecs. */ uint32_t __tcpi_last_data_sent; uint32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ uint32_t tcpi_last_data_recv; /* Time since last recv data. */ uint32_t __tcpi_last_ack_recv; /* Metrics; variable units. */ uint32_t __tcpi_pmtu; uint32_t __tcpi_rcv_ssthresh; uint32_t tcpi_rtt; /* Smoothed RTT in usecs. */ uint32_t tcpi_rttvar; /* RTT variance in usecs. */ uint32_t tcpi_snd_ssthresh; /* Slow start threshold. */ uint32_t tcpi_snd_cwnd; /* Send congestion window. */ uint32_t __tcpi_advmss; uint32_t __tcpi_reordering; uint32_t __tcpi_rcv_rtt; uint32_t tcpi_rcv_space; /* Advertised recv window. */ /* FreeBSD/NetBSD extensions to tcp_info. */ uint32_t tcpi_snd_wnd; /* Advertised send window. */ uint32_t tcpi_snd_bwnd; /* No longer used. */ uint32_t tcpi_snd_nxt; /* Next egress seqno */ uint32_t tcpi_rcv_nxt; /* Next ingress seqno */ uint32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ uint32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ uint32_t tcpi_rcv_ooopack; /* Out-of-order packets */ uint32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ /* Padding to grow without breaking ABI. */ uint32_t __tcpi_pad[26]; /* Padding. */ }; #endif /* !_NETINET_TCP_H_ */
