source: rtems/c/src/exec/libnetworking/net/pppcompress.h @ 85a0f07

4.104.114.84.95
Last change on this file since 85a0f07 was 85a0f07, checked in by Joel Sherrill <joel.sherrill@…>, on Nov 25, 2000 at 10:10:01 PM

2000-11-25 Antti P Miettinen <antti.p.miettinen@…>

  • wrapup/Makefile.am: Added modem subdir.
  • configure.in, Makefile.am: Added modem subdir.
  • net/Makefile.am: Added if_pppvar.h, pppcompress.h.
  • pppd/Makefile.am: Added pppmain.c (which needs work).
  • pppd/chat.c, pppd/fsm.c, pppd/fsm.h, pppd/ipxcp.c, pppd/main.c, pppd/ppp_tty.c, pppd/upap.c: Changes from Thomas Doerfler <Thomas.Doerfler@…> and cosmetic changes by me. Actually main.c and ppp_tty.c should be scratched. The modem subdir has the real ppp_tty.c and the real pppd main is in pppmain.c.
  • Property mode set to 100644
File size: 6.7 KB
Line 
1/*
2 * Definitions for tcp compression routines.
3 *
4 * Copyright (c) 1989 Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *      This product includes software developed by the University of
18 *      California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 *      Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
36 *      - Initial distribution.
37 *
38 *      From:   slcompress.h    7.4     90/06/28
39 *      $Id$
40 */
41
42#ifndef _NET_PPPCOMPRESS_H_
43#define _NET_PPPCOMPRESS_H_
44
45#define MAX_STATES 16           /* must be > 2 and < 256 */
46#define MAX_HDR MLEN            /* XXX 4bsd-ism: should really be 128 */
47
48/*
49 * Compressed packet format:
50 *
51 * The first octet contains the packet type (top 3 bits), TCP
52 * 'push' bit, and flags that indicate which of the 4 TCP sequence
53 * numbers have changed (bottom 5 bits).  The next octet is a
54 * conversation number that associates a saved IP/TCP header with
55 * the compressed packet.  The next two octets are the TCP checksum
56 * from the original datagram.  The next 0 to 15 octets are
57 * sequence number changes, one change per bit set in the header
58 * (there may be no changes and there are two special cases where
59 * the receiver implicitly knows what changed -- see below).
60 *
61 * There are 5 numbers which can change (they are always inserted
62 * in the following order): TCP urgent pointer, window,
63 * acknowlegement, sequence number and IP ID.  (The urgent pointer
64 * is different from the others in that its value is sent, not the
65 * change in value.)  Since typical use of SLIP links is biased
66 * toward small packets (see comments on MTU/MSS below), changes
67 * use a variable length coding with one octet for numbers in the
68 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
69 * range 256 - 65535 or 0.  (If the change in sequence number or
70 * ack is more than 65535, an uncompressed packet is sent.)
71 */
72
73/*
74 * Packet types (must not conflict with IP protocol version)
75 *
76 * The top nibble of the first octet is the packet type.  There are
77 * three possible types: IP (not proto TCP or tcp with one of the
78 * control flags set); uncompressed TCP (a normal IP/TCP packet but
79 * with the 8-bit protocol field replaced by an 8-bit connection id --
80 * this type of packet syncs the sender & receiver); and compressed
81 * TCP (described above).
82 *
83 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
84 * is logically part of the 4-bit "changes" field that follows.  Top
85 * three bits are actual packet type.  For backward compatibility
86 * and in the interest of conserving bits, numbers are chosen so the
87 * IP protocol version number (4) which normally appears in this nibble
88 * means "IP packet".
89 */
90
91/* packet types */
92#define TYPE_IP 0x40
93#define TYPE_UNCOMPRESSED_TCP 0x70
94#define TYPE_COMPRESSED_TCP 0x80
95#define TYPE_ERROR 0x00
96
97/* Bits in first octet of compressed packet */
98#define NEW_C   0x40    /* flag bits for what changed in a packet */
99#define NEW_I   0x20
100#define NEW_S   0x08
101#define NEW_A   0x04
102#define NEW_W   0x02
103#define NEW_U   0x01
104
105/* reserved, special-case values of above */
106#define SPECIAL_I (NEW_S|NEW_W|NEW_U)           /* echoed interactive traffic */
107#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U)     /* unidirectional data */
108#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
109
110#define TCP_PUSH_BIT 0x10
111
112
113/*
114 * "state" data for each active tcp conversation on the wire.  This is
115 * basically a copy of the entire IP/TCP header from the last packet
116 * we saw from the conversation together with a small identifier
117 * the transmit & receive ends of the line use to locate saved header.
118 */
119struct cstate {
120        struct cstate *cs_next; /* next most recently used cstate (xmit only) */
121        u_short cs_hlen;        /* size of hdr (receive only) */
122        u_char cs_id;           /* connection # associated with this state */
123        u_char cs_filler;
124        union {
125                char csu_hdr[MAX_HDR];
126                struct ip csu_ip;       /* ip/tcp hdr from most recent packet */
127        } slcs_u;
128};
129#define cs_ip slcs_u.csu_ip
130#define cs_hdr slcs_u.csu_hdr
131
132/*
133 * all the state data for one serial line (we need one of these
134 * per line).
135 */
136struct vjcompress {
137        struct cstate *last_cs; /* most recently used tstate */
138        u_char last_recv;       /* last rcvd conn. id */
139        u_char last_xmit;       /* last sent conn. id */
140        u_short flags;
141#ifndef SL_NO_STATS
142        int sls_packets;        /* outbound packets */
143        int sls_compressed;     /* outbound compressed packets */
144        int sls_searches;       /* searches for connection state */
145        int sls_misses;         /* times couldn't find conn. state */
146        int sls_uncompressedin; /* inbound uncompressed packets */
147        int sls_compressedin;   /* inbound compressed packets */
148        int sls_errorin;        /* inbound unknown type packets */
149        int sls_tossed;         /* inbound packets tossed because of error */
150#endif
151        struct cstate tstate[MAX_STATES];       /* xmit connection states */
152        struct cstate rstate[MAX_STATES];       /* receive connection states */
153};
154/* flag values */
155#define SLF_TOSS 1              /* tossing rcvd frames because of input err */
156
157void     vj_compress_init __P((struct vjcompress *, int));
158u_int    vj_compress_tcp __P((struct mbuf *,
159            struct ip *, struct vjcompress *, int));
160int      vj_uncompress_tcp __P((u_char **, int, u_int, struct vjcompress *));
161int      vj_uncompress_tcp_core __P((u_char *, int, int, u_int,
162            struct vjcompress *, u_char **, u_int *));
163
164#endif /* _NET_PPPCOMPRESS_H_ */
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