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      1 /*
      2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
      3  *		operating system.  INET is implemented using the  BSD Socket
      4  *		interface as the means of communication with the user level.
      5  *
      6  *		Definitions for the TCP protocol.
      7  *
      8  * Version:	@(#)tcp.h	1.0.2	04/28/93
      9  *
     10  * Author:	Fred N. van Kempen, <waltje (at) uWalt.NL.Mugnet.ORG>
     11  *
     12  *		This program is free software; you can redistribute it and/or
     13  *		modify it under the terms of the GNU General Public License
     14  *		as published by the Free Software Foundation; either version
     15  *		2 of the License, or (at your option) any later version.
     16  */
     17 #ifndef _LINUX_TCP_H
     18 #define _LINUX_TCP_H
     19 
     20 #include <linux/types.h>
     21 #include <asm/byteorder.h>
     22 #include <linux/socket.h>
     23 
     24 struct tcphdr {
     25 	__be16	source;
     26 	__be16	dest;
     27 	__be32	seq;
     28 	__be32	ack_seq;
     29 #if defined(__LITTLE_ENDIAN_BITFIELD)
     30 	__u16	res1:4,
     31 		doff:4,
     32 		fin:1,
     33 		syn:1,
     34 		rst:1,
     35 		psh:1,
     36 		ack:1,
     37 		urg:1,
     38 		ece:1,
     39 		cwr:1;
     40 #elif defined(__BIG_ENDIAN_BITFIELD)
     41 	__u16	doff:4,
     42 		res1:4,
     43 		cwr:1,
     44 		ece:1,
     45 		urg:1,
     46 		ack:1,
     47 		psh:1,
     48 		rst:1,
     49 		syn:1,
     50 		fin:1;
     51 #else
     52 #error	"Adjust your <asm/byteorder.h> defines"
     53 #endif
     54 	__be16	window;
     55 	__sum16	check;
     56 	__be16	urg_ptr;
     57 };
     58 
     59 /*
     60  *	The union cast uses a gcc extension to avoid aliasing problems
     61  *  (union is compatible to any of its members)
     62  *  This means this part of the code is -fstrict-aliasing safe now.
     63  */
     64 union tcp_word_hdr {
     65 	struct tcphdr hdr;
     66 	__be32 		  words[5];
     67 };
     68 
     69 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
     70 
     71 enum {
     72 	TCP_FLAG_CWR = __constant_htonl(0x00800000),
     73 	TCP_FLAG_ECE = __constant_htonl(0x00400000),
     74 	TCP_FLAG_URG = __constant_htonl(0x00200000),
     75 	TCP_FLAG_ACK = __constant_htonl(0x00100000),
     76 	TCP_FLAG_PSH = __constant_htonl(0x00080000),
     77 	TCP_FLAG_RST = __constant_htonl(0x00040000),
     78 	TCP_FLAG_SYN = __constant_htonl(0x00020000),
     79 	TCP_FLAG_FIN = __constant_htonl(0x00010000),
     80 	TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
     81 	TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
     82 };
     83 
     84 /* TCP socket options */
     85 #define TCP_NODELAY		1	/* Turn off Nagle's algorithm. */
     86 #define TCP_MAXSEG		2	/* Limit MSS */
     87 #define TCP_CORK		3	/* Never send partially complete segments */
     88 #define TCP_KEEPIDLE		4	/* Start keeplives after this period */
     89 #define TCP_KEEPINTVL		5	/* Interval between keepalives */
     90 #define TCP_KEEPCNT		6	/* Number of keepalives before death */
     91 #define TCP_SYNCNT		7	/* Number of SYN retransmits */
     92 #define TCP_LINGER2		8	/* Life time of orphaned FIN-WAIT-2 state */
     93 #define TCP_DEFER_ACCEPT	9	/* Wake up listener only when data arrive */
     94 #define TCP_WINDOW_CLAMP	10	/* Bound advertised window */
     95 #define TCP_INFO		11	/* Information about this connection. */
     96 #define TCP_QUICKACK		12	/* Block/reenable quick acks */
     97 #define TCP_CONGESTION		13	/* Congestion control algorithm */
     98 #define TCP_MD5SIG		14	/* TCP MD5 Signature (RFC2385) */
     99 
    100 #define TCPI_OPT_TIMESTAMPS	1
    101 #define TCPI_OPT_SACK		2
    102 #define TCPI_OPT_WSCALE		4
    103 #define TCPI_OPT_ECN		8
    104 
    105 enum tcp_ca_state
    106 {
    107 	TCP_CA_Open = 0,
    108 #define TCPF_CA_Open	(1<<TCP_CA_Open)
    109 	TCP_CA_Disorder = 1,
    110 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
    111 	TCP_CA_CWR = 2,
    112 #define TCPF_CA_CWR	(1<<TCP_CA_CWR)
    113 	TCP_CA_Recovery = 3,
    114 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
    115 	TCP_CA_Loss = 4
    116 #define TCPF_CA_Loss	(1<<TCP_CA_Loss)
    117 };
    118 
    119 struct tcp_info
    120 {
    121 	__u8	tcpi_state;
    122 	__u8	tcpi_ca_state;
    123 	__u8	tcpi_retransmits;
    124 	__u8	tcpi_probes;
    125 	__u8	tcpi_backoff;
    126 	__u8	tcpi_options;
    127 	__u8	tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
    128 
    129 	__u32	tcpi_rto;
    130 	__u32	tcpi_ato;
    131 	__u32	tcpi_snd_mss;
    132 	__u32	tcpi_rcv_mss;
    133 
    134 	__u32	tcpi_unacked;
    135 	__u32	tcpi_sacked;
    136 	__u32	tcpi_lost;
    137 	__u32	tcpi_retrans;
    138 	__u32	tcpi_fackets;
    139 
    140 	/* Times. */
    141 	__u32	tcpi_last_data_sent;
    142 	__u32	tcpi_last_ack_sent;     /* Not remembered, sorry. */
    143 	__u32	tcpi_last_data_recv;
    144 	__u32	tcpi_last_ack_recv;
    145 
    146 	/* Metrics. */
    147 	__u32	tcpi_pmtu;
    148 	__u32	tcpi_rcv_ssthresh;
    149 	__u32	tcpi_rtt;
    150 	__u32	tcpi_rttvar;
    151 	__u32	tcpi_snd_ssthresh;
    152 	__u32	tcpi_snd_cwnd;
    153 	__u32	tcpi_advmss;
    154 	__u32	tcpi_reordering;
    155 
    156 	__u32	tcpi_rcv_rtt;
    157 	__u32	tcpi_rcv_space;
    158 
    159 	__u32	tcpi_total_retrans;
    160 };
    161 
    162 /* for TCP_MD5SIG socket option */
    163 #define TCP_MD5SIG_MAXKEYLEN	80
    164 
    165 struct tcp_md5sig {
    166 	struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
    167 	__u16	__tcpm_pad1;				/* zero */
    168 	__u16	tcpm_keylen;				/* key length */
    169 	__u32	__tcpm_pad2;				/* zero */
    170 	__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];		/* key (binary) */
    171 };
    172 
    173 
    174 #endif	/* _LINUX_TCP_H */
    175