248 lines
9.0 KiB
C
248 lines
9.0 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp.h 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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*/
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#ifndef _NETINET_TCP_H_
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#define _NETINET_TCP_H_
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#if __BSD_VISIBLE
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typedef u_int32_t tcp_seq;
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#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */
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#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */
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/*
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* TCP header.
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* Per RFC 793, September, 1981.
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*/
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struct tcphdr {
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u_short th_sport; /* source port */
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u_short th_dport; /* destination port */
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tcp_seq th_seq; /* sequence number */
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tcp_seq th_ack; /* acknowledgement number */
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#if BYTE_ORDER == LITTLE_ENDIAN
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u_char th_x2:4, /* (unused) */
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th_off:4; /* data offset */
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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u_char th_off:4, /* data offset */
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th_x2:4; /* (unused) */
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#endif
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u_char th_flags;
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#define TH_FIN 0x01
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#define TH_SYN 0x02
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#define TH_RST 0x04
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#define TH_PUSH 0x08
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#define TH_ACK 0x10
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#define TH_URG 0x20
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#define TH_ECE 0x40
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#define TH_CWR 0x80
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#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR)
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#define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR"
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u_short th_win; /* window */
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u_short th_sum; /* checksum */
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u_short th_urp; /* urgent pointer */
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};
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#define TCPOPT_EOL 0
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#define TCPOLEN_EOL 1
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#define TCPOPT_PAD 0 /* padding after EOL */
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#define TCPOLEN_PAD 1
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#define TCPOPT_NOP 1
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#define TCPOLEN_NOP 1
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#define TCPOPT_MAXSEG 2
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#define TCPOLEN_MAXSEG 4
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#define TCPOPT_WINDOW 3
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#define TCPOLEN_WINDOW 3
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#define TCPOPT_SACK_PERMITTED 4
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#define TCPOLEN_SACK_PERMITTED 2
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#define TCPOPT_SACK 5
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#define TCPOLEN_SACKHDR 2
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#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */
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#define TCPOPT_TIMESTAMP 8
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#define TCPOLEN_TIMESTAMP 10
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#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */
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#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */
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#define TCPOLEN_SIGNATURE 18
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/* Miscellaneous constants */
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#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */
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#define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */
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/*
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* The default maximum segment size (MSS) to be used for new TCP connections
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* when path MTU discovery is not enabled.
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*
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* RFC879 derives the default MSS from the largest datagram size hosts are
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* minimally required to handle directly or through IP reassembly minus the
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* size of the IP and TCP header. With IPv6 the minimum MTU is specified
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* in RFC2460.
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*
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* For IPv4 the MSS is 576 - sizeof(struct tcpiphdr)
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* For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr)
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*
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* We use explicit numerical definition here to avoid header pollution.
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*/
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#define TCP_MSS 536
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#define TCP6_MSS 1220
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/*
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* Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS
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* option. Allowing low values of MSS can consume significant resources and
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* be used to mount a resource exhaustion attack.
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* Connections requesting lower MSS values will be rounded up to this value
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* and the IP_DF flag will be cleared to allow fragmentation along the path.
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*
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* See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting
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* it to "0" disables the minmss check.
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*
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* The default value is fine for TCP across the Internet's smallest official
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* link MTU (256 bytes for AX.25 packet radio). However, a connection is very
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* unlikely to come across such low MTU interfaces these days (anno domini 2003).
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*/
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#define TCP_MINMSS 216
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#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
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#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */
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#define TCP_MAX_WINSHIFT 14 /* maximum window shift */
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#define TCP_MAXBURST 4 /* maximum segments in a burst */
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#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */
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#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr))
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/* max space left for options */
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#endif /* __BSD_VISIBLE */
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/*
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* User-settable options (used with setsockopt). These are discrete
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* values and are not masked together. Some values appear to be
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* bitmasks for historical reasons.
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*/
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#define TCP_NODELAY 1 /* don't delay send to coalesce packets */
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#if __BSD_VISIBLE
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#define TCP_MAXSEG 2 /* set maximum segment size */
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#define TCP_NOPUSH 4 /* don't push last block of write */
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#define TCP_NOOPT 8 /* don't use TCP options */
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#define TCP_MD5SIG 16 /* use MD5 digests (RFC2385) */
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#define TCP_INFO 32 /* retrieve tcp_info structure */
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#define TCP_CONGESTION 64 /* get/set congestion control algorithm */
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#define TCP_KEEPINIT 128 /* N, time to establish connection */
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#define TCP_KEEPIDLE 256 /* L,N,X start keeplives after this period */
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#define TCP_KEEPINTVL 512 /* L,N interval between keepalives */
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#define TCP_KEEPCNT 1024 /* L,N number of keepalives before close */
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/* Start of reserved space for third-party user-settable options. */
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#define TCP_VENDOR SO_VENDOR
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#define TCP_CA_NAME_MAX 16 /* max congestion control name length */
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#define TCPI_OPT_TIMESTAMPS 0x01
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#define TCPI_OPT_SACK 0x02
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#define TCPI_OPT_WSCALE 0x04
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#define TCPI_OPT_ECN 0x08
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#define TCPI_OPT_TOE 0x10
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/*
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* The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits
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* the caller to query certain information about the state of a TCP
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* connection. We provide an overlapping set of fields with the Linux
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* implementation, but since this is a fixed size structure, room has been
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* left for growth. In order to maximize potential future compatibility with
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* the Linux API, the same variable names and order have been adopted, and
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* padding left to make room for omitted fields in case they are added later.
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*
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* XXX: This is currently an unstable ABI/API, in that it is expected to
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* change.
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*/
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struct tcp_info {
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u_int8_t tcpi_state; /* TCP FSM state. */
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u_int8_t __tcpi_ca_state;
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u_int8_t __tcpi_retransmits;
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u_int8_t __tcpi_probes;
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u_int8_t __tcpi_backoff;
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u_int8_t tcpi_options; /* Options enabled on conn. */
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u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */
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tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */
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u_int32_t tcpi_rto; /* Retransmission timeout (usec). */
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u_int32_t __tcpi_ato;
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u_int32_t tcpi_snd_mss; /* Max segment size for send. */
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u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */
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u_int32_t __tcpi_unacked;
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u_int32_t __tcpi_sacked;
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u_int32_t __tcpi_lost;
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u_int32_t __tcpi_retrans;
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u_int32_t __tcpi_fackets;
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/* Times; measurements in usecs. */
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u_int32_t __tcpi_last_data_sent;
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u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */
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u_int32_t tcpi_last_data_recv; /* Time since last recv data. */
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u_int32_t __tcpi_last_ack_recv;
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/* Metrics; variable units. */
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u_int32_t __tcpi_pmtu;
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u_int32_t __tcpi_rcv_ssthresh;
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u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */
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u_int32_t tcpi_rttvar; /* RTT variance in usecs. */
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u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */
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u_int32_t tcpi_snd_cwnd; /* Send congestion window. */
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u_int32_t __tcpi_advmss;
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u_int32_t __tcpi_reordering;
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u_int32_t __tcpi_rcv_rtt;
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u_int32_t tcpi_rcv_space; /* Advertised recv window. */
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/* FreeBSD extensions to tcp_info. */
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u_int32_t tcpi_snd_wnd; /* Advertised send window. */
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u_int32_t tcpi_snd_bwnd; /* No longer used. */
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u_int32_t tcpi_snd_nxt; /* Next egress seqno */
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u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */
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u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */
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u_int32_t tcpi_snd_rexmitpack; /* Retransmitted packets */
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u_int32_t tcpi_rcv_ooopack; /* Out-of-order packets */
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u_int32_t tcpi_snd_zerowin; /* Zero-sized windows sent */
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/* Padding to grow without breaking ABI. */
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u_int32_t __tcpi_pad[26]; /* Padding. */
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};
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#endif
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#endif /* !_NETINET_TCP_H_ */
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