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Dependencies:   mbed

NetServices/lwip/netif/ppp/vj.h@1:f5ac63519541, 2014-03-05 (annotated)

Committer:
Michael J. Spencer
Date:
Wed Mar 05 06:14:02 2014 -0800
Revision:
1:f5ac63519541
Initial commit.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Michael J. Spencer 1:f5ac63519541 1 /*
Michael J. Spencer 1:f5ac63519541 2 * Definitions for tcp compression routines.
Michael J. Spencer 1:f5ac63519541 3 *
Michael J. Spencer 1:f5ac63519541 4 * $Id: vj.h,v 1.7 2010/02/22 17:52:09 goldsimon Exp $
Michael J. Spencer 1:f5ac63519541 5 *
Michael J. Spencer 1:f5ac63519541 6 * Copyright (c) 1989 Regents of the University of California.
Michael J. Spencer 1:f5ac63519541 7 * All rights reserved.
Michael J. Spencer 1:f5ac63519541 8 *
Michael J. Spencer 1:f5ac63519541 9 * Redistribution and use in source and binary forms are permitted
Michael J. Spencer 1:f5ac63519541 10 * provided that the above copyright notice and this paragraph are
Michael J. Spencer 1:f5ac63519541 11 * duplicated in all such forms and that any documentation,
Michael J. Spencer 1:f5ac63519541 12 * advertising materials, and other materials related to such
Michael J. Spencer 1:f5ac63519541 13 * distribution and use acknowledge that the software was developed
Michael J. Spencer 1:f5ac63519541 14 * by the University of California, Berkeley. The name of the
Michael J. Spencer 1:f5ac63519541 15 * University may not be used to endorse or promote products derived
Michael J. Spencer 1:f5ac63519541 16 * from this software without specific prior written permission.
Michael J. Spencer 1:f5ac63519541 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
Michael J. Spencer 1:f5ac63519541 18 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
Michael J. Spencer 1:f5ac63519541 19 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Michael J. Spencer 1:f5ac63519541 20 *
Michael J. Spencer 1:f5ac63519541 21 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
Michael J. Spencer 1:f5ac63519541 22 * - Initial distribution.
Michael J. Spencer 1:f5ac63519541 23 */
Michael J. Spencer 1:f5ac63519541 24
Michael J. Spencer 1:f5ac63519541 25 #ifndef VJ_H
Michael J. Spencer 1:f5ac63519541 26 #define VJ_H
Michael J. Spencer 1:f5ac63519541 27
Michael J. Spencer 1:f5ac63519541 28 #include "lwip/ip.h"
Michael J. Spencer 1:f5ac63519541 29 #include "lwip/tcp_impl.h"
Michael J. Spencer 1:f5ac63519541 30
Michael J. Spencer 1:f5ac63519541 31 #define MAX_SLOTS 16 /* must be > 2 and < 256 */
Michael J. Spencer 1:f5ac63519541 32 #define MAX_HDR 128
Michael J. Spencer 1:f5ac63519541 33
Michael J. Spencer 1:f5ac63519541 34 /*
Michael J. Spencer 1:f5ac63519541 35 * Compressed packet format:
Michael J. Spencer 1:f5ac63519541 36 *
Michael J. Spencer 1:f5ac63519541 37 * The first octet contains the packet type (top 3 bits), TCP
Michael J. Spencer 1:f5ac63519541 38 * 'push' bit, and flags that indicate which of the 4 TCP sequence
Michael J. Spencer 1:f5ac63519541 39 * numbers have changed (bottom 5 bits). The next octet is a
Michael J. Spencer 1:f5ac63519541 40 * conversation number that associates a saved IP/TCP header with
Michael J. Spencer 1:f5ac63519541 41 * the compressed packet. The next two octets are the TCP checksum
Michael J. Spencer 1:f5ac63519541 42 * from the original datagram. The next 0 to 15 octets are
Michael J. Spencer 1:f5ac63519541 43 * sequence number changes, one change per bit set in the header
Michael J. Spencer 1:f5ac63519541 44 * (there may be no changes and there are two special cases where
Michael J. Spencer 1:f5ac63519541 45 * the receiver implicitly knows what changed -- see below).
Michael J. Spencer 1:f5ac63519541 46 *
Michael J. Spencer 1:f5ac63519541 47 * There are 5 numbers which can change (they are always inserted
Michael J. Spencer 1:f5ac63519541 48 * in the following order): TCP urgent pointer, window,
Michael J. Spencer 1:f5ac63519541 49 * acknowlegement, sequence number and IP ID. (The urgent pointer
Michael J. Spencer 1:f5ac63519541 50 * is different from the others in that its value is sent, not the
Michael J. Spencer 1:f5ac63519541 51 * change in value.) Since typical use of SLIP links is biased
Michael J. Spencer 1:f5ac63519541 52 * toward small packets (see comments on MTU/MSS below), changes
Michael J. Spencer 1:f5ac63519541 53 * use a variable length coding with one octet for numbers in the
Michael J. Spencer 1:f5ac63519541 54 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
Michael J. Spencer 1:f5ac63519541 55 * range 256 - 65535 or 0. (If the change in sequence number or
Michael J. Spencer 1:f5ac63519541 56 * ack is more than 65535, an uncompressed packet is sent.)
Michael J. Spencer 1:f5ac63519541 57 */
Michael J. Spencer 1:f5ac63519541 58
Michael J. Spencer 1:f5ac63519541 59 /*
Michael J. Spencer 1:f5ac63519541 60 * Packet types (must not conflict with IP protocol version)
Michael J. Spencer 1:f5ac63519541 61 *
Michael J. Spencer 1:f5ac63519541 62 * The top nibble of the first octet is the packet type. There are
Michael J. Spencer 1:f5ac63519541 63 * three possible types: IP (not proto TCP or tcp with one of the
Michael J. Spencer 1:f5ac63519541 64 * control flags set); uncompressed TCP (a normal IP/TCP packet but
Michael J. Spencer 1:f5ac63519541 65 * with the 8-bit protocol field replaced by an 8-bit connection id --
Michael J. Spencer 1:f5ac63519541 66 * this type of packet syncs the sender & receiver); and compressed
Michael J. Spencer 1:f5ac63519541 67 * TCP (described above).
Michael J. Spencer 1:f5ac63519541 68 *
Michael J. Spencer 1:f5ac63519541 69 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
Michael J. Spencer 1:f5ac63519541 70 * is logically part of the 4-bit "changes" field that follows. Top
Michael J. Spencer 1:f5ac63519541 71 * three bits are actual packet type. For backward compatibility
Michael J. Spencer 1:f5ac63519541 72 * and in the interest of conserving bits, numbers are chosen so the
Michael J. Spencer 1:f5ac63519541 73 * IP protocol version number (4) which normally appears in this nibble
Michael J. Spencer 1:f5ac63519541 74 * means "IP packet".
Michael J. Spencer 1:f5ac63519541 75 */
Michael J. Spencer 1:f5ac63519541 76
Michael J. Spencer 1:f5ac63519541 77 /* packet types */
Michael J. Spencer 1:f5ac63519541 78 #define TYPE_IP 0x40
Michael J. Spencer 1:f5ac63519541 79 #define TYPE_UNCOMPRESSED_TCP 0x70
Michael J. Spencer 1:f5ac63519541 80 #define TYPE_COMPRESSED_TCP 0x80
Michael J. Spencer 1:f5ac63519541 81 #define TYPE_ERROR 0x00
Michael J. Spencer 1:f5ac63519541 82
Michael J. Spencer 1:f5ac63519541 83 /* Bits in first octet of compressed packet */
Michael J. Spencer 1:f5ac63519541 84 #define NEW_C 0x40 /* flag bits for what changed in a packet */
Michael J. Spencer 1:f5ac63519541 85 #define NEW_I 0x20
Michael J. Spencer 1:f5ac63519541 86 #define NEW_S 0x08
Michael J. Spencer 1:f5ac63519541 87 #define NEW_A 0x04
Michael J. Spencer 1:f5ac63519541 88 #define NEW_W 0x02
Michael J. Spencer 1:f5ac63519541 89 #define NEW_U 0x01
Michael J. Spencer 1:f5ac63519541 90
Michael J. Spencer 1:f5ac63519541 91 /* reserved, special-case values of above */
Michael J. Spencer 1:f5ac63519541 92 #define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */
Michael J. Spencer 1:f5ac63519541 93 #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */
Michael J. Spencer 1:f5ac63519541 94 #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
Michael J. Spencer 1:f5ac63519541 95
Michael J. Spencer 1:f5ac63519541 96 #define TCP_PUSH_BIT 0x10
Michael J. Spencer 1:f5ac63519541 97
Michael J. Spencer 1:f5ac63519541 98
Michael J. Spencer 1:f5ac63519541 99 /*
Michael J. Spencer 1:f5ac63519541 100 * "state" data for each active tcp conversation on the wire. This is
Michael J. Spencer 1:f5ac63519541 101 * basically a copy of the entire IP/TCP header from the last packet
Michael J. Spencer 1:f5ac63519541 102 * we saw from the conversation together with a small identifier
Michael J. Spencer 1:f5ac63519541 103 * the transmit & receive ends of the line use to locate saved header.
Michael J. Spencer 1:f5ac63519541 104 */
Michael J. Spencer 1:f5ac63519541 105 struct cstate {
Michael J. Spencer 1:f5ac63519541 106 struct cstate *cs_next; /* next most recently used state (xmit only) */
Michael J. Spencer 1:f5ac63519541 107 u_short cs_hlen; /* size of hdr (receive only) */
Michael J. Spencer 1:f5ac63519541 108 u_char cs_id; /* connection # associated with this state */
Michael J. Spencer 1:f5ac63519541 109 u_char cs_filler;
Michael J. Spencer 1:f5ac63519541 110 union {
Michael J. Spencer 1:f5ac63519541 111 char csu_hdr[MAX_HDR];
Michael J. Spencer 1:f5ac63519541 112 struct ip_hdr csu_ip; /* ip/tcp hdr from most recent packet */
Michael J. Spencer 1:f5ac63519541 113 } vjcs_u;
Michael J. Spencer 1:f5ac63519541 114 };
Michael J. Spencer 1:f5ac63519541 115 #define cs_ip vjcs_u.csu_ip
Michael J. Spencer 1:f5ac63519541 116 #define cs_hdr vjcs_u.csu_hdr
Michael J. Spencer 1:f5ac63519541 117
Michael J. Spencer 1:f5ac63519541 118
Michael J. Spencer 1:f5ac63519541 119 struct vjstat {
Michael J. Spencer 1:f5ac63519541 120 unsigned long vjs_packets; /* outbound packets */
Michael J. Spencer 1:f5ac63519541 121 unsigned long vjs_compressed; /* outbound compressed packets */
Michael J. Spencer 1:f5ac63519541 122 unsigned long vjs_searches; /* searches for connection state */
Michael J. Spencer 1:f5ac63519541 123 unsigned long vjs_misses; /* times couldn't find conn. state */
Michael J. Spencer 1:f5ac63519541 124 unsigned long vjs_uncompressedin; /* inbound uncompressed packets */
Michael J. Spencer 1:f5ac63519541 125 unsigned long vjs_compressedin; /* inbound compressed packets */
Michael J. Spencer 1:f5ac63519541 126 unsigned long vjs_errorin; /* inbound unknown type packets */
Michael J. Spencer 1:f5ac63519541 127 unsigned long vjs_tossed; /* inbound packets tossed because of error */
Michael J. Spencer 1:f5ac63519541 128 };
Michael J. Spencer 1:f5ac63519541 129
Michael J. Spencer 1:f5ac63519541 130 /*
Michael J. Spencer 1:f5ac63519541 131 * all the state data for one serial line (we need one of these per line).
Michael J. Spencer 1:f5ac63519541 132 */
Michael J. Spencer 1:f5ac63519541 133 struct vjcompress {
Michael J. Spencer 1:f5ac63519541 134 struct cstate *last_cs; /* most recently used tstate */
Michael J. Spencer 1:f5ac63519541 135 u_char last_recv; /* last rcvd conn. id */
Michael J. Spencer 1:f5ac63519541 136 u_char last_xmit; /* last sent conn. id */
Michael J. Spencer 1:f5ac63519541 137 u_short flags;
Michael J. Spencer 1:f5ac63519541 138 u_char maxSlotIndex;
Michael J. Spencer 1:f5ac63519541 139 u_char compressSlot; /* Flag indicating OK to compress slot ID. */
Michael J. Spencer 1:f5ac63519541 140 #if LINK_STATS
Michael J. Spencer 1:f5ac63519541 141 struct vjstat stats;
Michael J. Spencer 1:f5ac63519541 142 #endif
Michael J. Spencer 1:f5ac63519541 143 struct cstate tstate[MAX_SLOTS]; /* xmit connection states */
Michael J. Spencer 1:f5ac63519541 144 struct cstate rstate[MAX_SLOTS]; /* receive connection states */
Michael J. Spencer 1:f5ac63519541 145 };
Michael J. Spencer 1:f5ac63519541 146
Michael J. Spencer 1:f5ac63519541 147 /* flag values */
Michael J. Spencer 1:f5ac63519541 148 #define VJF_TOSS 1U /* tossing rcvd frames because of input err */
Michael J. Spencer 1:f5ac63519541 149
Michael J. Spencer 1:f5ac63519541 150 extern void vj_compress_init (struct vjcompress *comp);
Michael J. Spencer 1:f5ac63519541 151 extern u_int vj_compress_tcp (struct vjcompress *comp, struct pbuf *pb);
Michael J. Spencer 1:f5ac63519541 152 extern void vj_uncompress_err (struct vjcompress *comp);
Michael J. Spencer 1:f5ac63519541 153 extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
Michael J. Spencer 1:f5ac63519541 154 extern int vj_uncompress_tcp (struct pbuf **nb, struct vjcompress *comp);
Michael J. Spencer 1:f5ac63519541 155
Michael J. Spencer 1:f5ac63519541 156 #endif /* VJ_H */