This file is indexed.

/usr/include/netinet/tcp.h is in libc6-dev 2.15-0ubuntu10.18.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
/*
 * 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
 */

#ifndef _NETINET_TCP_H
#define _NETINET_TCP_H	1

#include <features.h>

/*
 * 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_CORK	 3	/* Control sending of partial frames  */
#define TCP_KEEPIDLE	 4	/* Start keeplives after this period */
#define TCP_KEEPINTVL	 5	/* Interval between keepalives */
#define TCP_KEEPCNT	 6	/* Number of keepalives before death */
#define TCP_SYNCNT	 7	/* Number of SYN retransmits */
#define TCP_LINGER2	 8	/* Life time of orphaned FIN-WAIT-2 state */
#define TCP_DEFER_ACCEPT 9	/* Wake up listener only when data arrive */
#define TCP_WINDOW_CLAMP 10	/* Bound advertised window */
#define TCP_INFO	 11	/* Information about this connection. */
#define	TCP_QUICKACK	 12	/* Bock/reenable quick ACKs.  */
#define TCP_CONGESTION	 13	/* Congestion control algorithm.  */
#define TCP_MD5SIG	 14	/* TCP MD5 Signature (RFC2385) */

#ifdef __USE_MISC
# include <sys/types.h>
# include <sys/socket.h>

# ifdef __FAVOR_BSD
typedef	u_int32_t tcp_seq;
/*
 * TCP header.
 * Per RFC 793, September, 1981.
 */
struct tcphdr
  {
    u_int16_t th_sport;		/* source port */
    u_int16_t th_dport;		/* destination port */
    tcp_seq th_seq;		/* sequence number */
    tcp_seq th_ack;		/* acknowledgement number */
#  if __BYTE_ORDER == __LITTLE_ENDIAN
    u_int8_t th_x2:4;		/* (unused) */
    u_int8_t th_off:4;		/* data offset */
#  endif
#  if __BYTE_ORDER == __BIG_ENDIAN
    u_int8_t th_off:4;		/* data offset */
    u_int8_t th_x2:4;		/* (unused) */
#  endif
    u_int8_t 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
    u_int16_t th_win;		/* window */
    u_int16_t th_sum;		/* checksum */
    u_int16_t th_urp;		/* urgent pointer */
};

# else /* !__FAVOR_BSD */
struct tcphdr
  {
    u_int16_t source;
    u_int16_t dest;
    u_int32_t seq;
    u_int32_t ack_seq;
#  if __BYTE_ORDER == __LITTLE_ENDIAN
    u_int16_t res1:4;
    u_int16_t doff:4;
    u_int16_t fin:1;
    u_int16_t syn:1;
    u_int16_t rst:1;
    u_int16_t psh:1;
    u_int16_t ack:1;
    u_int16_t urg:1;
    u_int16_t res2:2;
#  elif __BYTE_ORDER == __BIG_ENDIAN
    u_int16_t doff:4;
    u_int16_t res1:4;
    u_int16_t res2:2;
    u_int16_t urg:1;
    u_int16_t ack:1;
    u_int16_t psh:1;
    u_int16_t rst:1;
    u_int16_t syn:1;
    u_int16_t fin:1;
#  else
#   error "Adjust your <bits/endian.h> defines"
#  endif
    u_int16_t window;
    u_int16_t check;
    u_int16_t urg_ptr;
};
# endif /* __FAVOR_BSD */

enum
{
  TCP_ESTABLISHED = 1,
  TCP_SYN_SENT,
  TCP_SYN_RECV,
  TCP_FIN_WAIT1,
  TCP_FIN_WAIT2,
  TCP_TIME_WAIT,
  TCP_CLOSE,
  TCP_CLOSE_WAIT,
  TCP_LAST_ACK,
  TCP_LISTEN,
  TCP_CLOSING   /* now a valid state */
};

# define TCPOPT_EOL		0
# define TCPOPT_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)

/*
 * Default maximum segment size for TCP.
 * With an IP MSS of 576, this is 536,
 * but 512 is probably more convenient.
 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 */
# define TCP_MSS	512

# define TCP_MAXWIN	65535	/* largest value for (unscaled) window */

# define TCP_MAX_WINSHIFT	14	/* maximum window shift */

# define SOL_TCP		6	/* TCP level */


# define TCPI_OPT_TIMESTAMPS	1
# define TCPI_OPT_SACK		2
# define TCPI_OPT_WSCALE	4
# define TCPI_OPT_ECN		8

/* Values for tcpi_state.  */
enum tcp_ca_state
{
  TCP_CA_Open = 0,
  TCP_CA_Disorder = 1,
  TCP_CA_CWR = 2,
  TCP_CA_Recovery = 3,
  TCP_CA_Loss = 4
};

struct tcp_info
{
  u_int8_t	tcpi_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;
  u_int8_t	tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;

  u_int32_t	tcpi_rto;
  u_int32_t	tcpi_ato;
  u_int32_t	tcpi_snd_mss;
  u_int32_t	tcpi_rcv_mss;

  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. */
  u_int32_t	tcpi_last_data_sent;
  u_int32_t	tcpi_last_ack_sent;	/* Not remembered, sorry.  */
  u_int32_t	tcpi_last_data_recv;
  u_int32_t	tcpi_last_ack_recv;

  /* Metrics. */
  u_int32_t	tcpi_pmtu;
  u_int32_t	tcpi_rcv_ssthresh;
  u_int32_t	tcpi_rtt;
  u_int32_t	tcpi_rttvar;
  u_int32_t	tcpi_snd_ssthresh;
  u_int32_t	tcpi_snd_cwnd;
  u_int32_t	tcpi_advmss;
  u_int32_t	tcpi_reordering;

  u_int32_t	tcpi_rcv_rtt;
  u_int32_t	tcpi_rcv_space;

  u_int32_t	tcpi_total_retrans;
};


/* For TCP_MD5SIG socket option.  */
#define TCP_MD5SIG_MAXKEYLEN	80

struct tcp_md5sig
{
  struct sockaddr_storage tcpm_addr;		/* Address associated.  */
  u_int16_t	__tcpm_pad1;			/* Zero.  */
  u_int16_t	tcpm_keylen;			/* Key length.  */
  u_int32_t	__tcpm_pad2;			/* Zero.  */
  u_int8_t	tcpm_key[TCP_MD5SIG_MAXKEYLEN];	/* Key (binary).  */
};

#endif /* Misc.  */

#endif /* netinet/tcp.h */