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Diffstat (limited to 'sys/netinet/tcp.h')
| -rw-r--r-- | sys/netinet/tcp.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/sys/netinet/tcp.h b/sys/netinet/tcp.h new file mode 100644 index 0000000..fb2f810 --- /dev/null +++ b/sys/netinet/tcp.h @@ -0,0 +1,247 @@ +/*- + * 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. + * 4. 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 <sys/cdefs.h> +#include <sys/types.h> + +#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 + +/* 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_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 */ + +/* 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 + +#endif /* !_NETINET_TCP_H_ */ |
