/*- * SPDX-License-Identifier: BSD-3-Clause * * 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 * $FreeBSD$ */ #ifndef _NETINET_TCP_H_ #define _NETINET_TCP_H_ #include #include #if __BSD_VISIBLE typedef u_int32_t tcp_seq; #define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ #define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ /* * TCP header. * Per RFC 793, September, 1981. */ struct tcphdr { u_short th_sport; /* source port */ u_short th_dport; /* destination port */ tcp_seq th_seq; /* sequence number */ tcp_seq th_ack; /* acknowledgement number */ #if BYTE_ORDER == LITTLE_ENDIAN u_char th_x2:4, /* (unused) */ th_off:4; /* data offset */ #endif #if BYTE_ORDER == BIG_ENDIAN u_char th_off:4, /* data offset */ th_x2:4; /* (unused) */ #endif u_char th_flags; #define TH_FIN 0x01 #define TH_SYN 0x02 #define TH_RST 0x04 #define TH_PUSH 0x08 #define TH_ACK 0x10 #define TH_URG 0x20 #define TH_ECE 0x40 #define TH_CWR 0x80 #define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG|TH_ECE|TH_CWR) #define PRINT_TH_FLAGS "\20\1FIN\2SYN\3RST\4PUSH\5ACK\6URG\7ECE\10CWR" u_short th_win; /* window */ u_short th_sum; /* checksum */ u_short th_urp; /* urgent pointer */ }; #define TCPOPT_EOL 0 #define TCPOLEN_EOL 1 #define TCPOPT_PAD 0 /* padding after EOL */ #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 #define TCPOLEN_SACK_PERMITTED 2 #define TCPOPT_SACK 5 #define TCPOLEN_SACKHDR 2 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ #define TCPOPT_TIMESTAMP 8 #define TCPOLEN_TIMESTAMP 10 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ #define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */ #define TCPOLEN_SIGNATURE 18 #define TCPOPT_FAST_OPEN 34 #define TCPOLEN_FAST_OPEN_EMPTY 2 #define TCPOLEN_FAST_OPEN_MIN 6 #define TCPOLEN_FAST_OPEN_MAX 18 /* Miscellaneous constants */ #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ #define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */ /* * The default maximum segment size (MSS) to be used for new TCP connections * when path MTU discovery is not enabled. * * RFC879 derives the default MSS from the largest datagram size hosts are * minimally required to handle directly or through IP reassembly minus the * size of the IP and TCP header. With IPv6 the minimum MTU is specified * in RFC2460. * * For IPv4 the MSS is 576 - sizeof(struct tcpiphdr) * For IPv6 the MSS is IPV6_MMTU - sizeof(struct ip6_hdr) - sizeof(struct tcphdr) * * We use explicit numerical definition here to avoid header pollution. */ #define TCP_MSS 536 #define TCP6_MSS 1220 /* * Limit the lowest MSS we accept for path MTU discovery and the TCP SYN MSS * option. Allowing low values of MSS can consume significant resources and * be used to mount a resource exhaustion attack. * Connections requesting lower MSS values will be rounded up to this value * and the IP_DF flag will be cleared to allow fragmentation along the path. * * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. Setting * it to "0" disables the minmss check. * * The default value is fine for TCP across the Internet's smallest official * link MTU (256 bytes for AX.25 packet radio). However, a connection is very * unlikely to come across such low MTU interfaces these days (anno domini 2003). */ #define TCP_MINMSS 216 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ #define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ #define TCP_MAXBURST 4 /* maximum segments in a burst */ #define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ #define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) /* max space left for options */ #endif /* __BSD_VISIBLE */ /* * User-settable options (used with setsockopt). These are discrete * values and are not masked together. Some values appear to be * bitmasks for historical reasons. */ #define TCP_NODELAY 1 /* don't delay send to coalesce packets */ #if __BSD_VISIBLE #define TCP_MAXSEG 2 /* set maximum segment size */ #define TCP_NOPUSH 4 /* don't push last block of write */ #define TCP_NOOPT 8 /* don't use TCP options */ #define TCP_MD5SIG 16 /* use MD5 digests (RFC2385) */ #define TCP_INFO 32 /* retrieve tcp_info structure */ #define TCP_CONGESTION 64 /* get/set congestion control algorithm */ #define TCP_CCALGOOPT 65 /* get/set cc algorithm specific options */ #define TCP_KEEPINIT 128 /* N, time to establish connection */ #define TCP_KEEPIDLE 256 /* L,N,X start keeplives after this period */ #define TCP_KEEPINTVL 512 /* L,N interval between keepalives */ #define TCP_KEEPCNT 1024 /* L,N number of keepalives before close */ #define TCP_FASTOPEN 1025 /* enable TFO / was created via TFO */ #define TCP_PCAP_OUT 2048 /* number of output packets to keep */ #define TCP_PCAP_IN 4096 /* number of input packets to keep */ #define TCP_FUNCTION_BLK 8192 /* Set the tcp function pointers to the specified stack */ /* Start of reserved space for third-party user-settable options. */ #define TCP_VENDOR SO_VENDOR #define TCP_CA_NAME_MAX 16 /* max congestion control name length */ #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 { u_int8_t tcpi_state; /* TCP FSM state. */ u_int8_t __tcpi_ca_state; u_int8_t __tcpi_retransmits; u_int8_t __tcpi_probes; u_int8_t __tcpi_backoff; u_int8_t tcpi_options; /* Options enabled on conn. */ u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */ tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */ u_int32_t tcpi_rto; /* Retransmission timeout (usec). */ u_int32_t __tcpi_ato; u_int32_t tcpi_snd_mss; /* Max segment size for send. */ u_int32_t tcpi_rcv_mss; /* Max segment size for receive. */ u_int32_t __tcpi_unacked; u_int32_t __tcpi_sacked; u_int32_t __tcpi_lost; u_int32_t __tcpi_retrans; u_int32_t __tcpi_fackets; /* Times; measurements in usecs. */ u_int32_t __tcpi_last_data_sent; u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */ u_int32_t tcpi_last_data_recv; /* Time since last recv data. */ u_int32_t __tcpi_last_ack_recv; /* Metrics; variable units. */ u_int32_t __tcpi_pmtu; u_int32_t __tcpi_rcv_ssthresh; u_int32_t tcpi_rtt; /* Smoothed RTT in usecs. */ u_int32_t tcpi_rttvar; /* RTT variance in usecs. */ u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */ u_int32_t tcpi_snd_cwnd; /* Send congestion window. */ u_int32_t __tcpi_advmss; u_int32_t __tcpi_reordering; u_int32_t __tcpi_rcv_rtt; u_int32_t tcpi_rcv_space; /* Advertised recv window. */ /* FreeBSD extensions to tcp_info. */ u_int32_t tcpi_snd_wnd; /* Advertised send window. */ u_int32_t tcpi_snd_bwnd; /* No longer used. */ u_int32_t tcpi_snd_nxt; /* Next egress seqno */ u_int32_t tcpi_rcv_nxt; /* Next ingress seqno */ u_int32_t tcpi_toe_tid; /* HWTID for TOE endpoints */ u_int32_t tcpi_snd_rexmitpack; /* Retransmitted packets */ u_int32_t tcpi_rcv_ooopack; /* Out-of-order packets */ u_int32_t tcpi_snd_zerowin; /* Zero-sized windows sent */ /* Padding to grow without breaking ABI. */ u_int32_t __tcpi_pad[26]; /* Padding. */ }; #endif #define TCP_FUNCTION_NAME_LEN_MAX 32 struct tcp_function_set { char function_set_name[TCP_FUNCTION_NAME_LEN_MAX]; uint32_t pcbcnt; }; #endif /* !_NETINET_TCP_H_ */