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netif/ppp/vj.h@0:51ac1d130fd4, 2012-06-22 (annotated)

Committer:
mbed_official
Date:
Fri Jun 22 09:25:39 2012 +0000
Revision:
0:51ac1d130fd4
Initial import from lwip-1.4.0: http://download.savannah.gnu.org/releases/lwip/lwip-1.4.0.zip

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:51ac1d130fd4 1 /*
mbed_official 0:51ac1d130fd4 2 * Definitions for tcp compression routines.
mbed_official 0:51ac1d130fd4 3 *
mbed_official 0:51ac1d130fd4 4 * $Id: vj.h,v 1.7 2010/02/22 17:52:09 goldsimon Exp $
mbed_official 0:51ac1d130fd4 5 *
mbed_official 0:51ac1d130fd4 6 * Copyright (c) 1989 Regents of the University of California.
mbed_official 0:51ac1d130fd4 7 * All rights reserved.
mbed_official 0:51ac1d130fd4 8 *
mbed_official 0:51ac1d130fd4 9 * Redistribution and use in source and binary forms are permitted
mbed_official 0:51ac1d130fd4 10 * provided that the above copyright notice and this paragraph are
mbed_official 0:51ac1d130fd4 11 * duplicated in all such forms and that any documentation,
mbed_official 0:51ac1d130fd4 12 * advertising materials, and other materials related to such
mbed_official 0:51ac1d130fd4 13 * distribution and use acknowledge that the software was developed
mbed_official 0:51ac1d130fd4 14 * by the University of California, Berkeley. The name of the
mbed_official 0:51ac1d130fd4 15 * University may not be used to endorse or promote products derived
mbed_official 0:51ac1d130fd4 16 * from this software without specific prior written permission.
mbed_official 0:51ac1d130fd4 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
mbed_official 0:51ac1d130fd4 18 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
mbed_official 0:51ac1d130fd4 19 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
mbed_official 0:51ac1d130fd4 20 *
mbed_official 0:51ac1d130fd4 21 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
mbed_official 0:51ac1d130fd4 22 * - Initial distribution.
mbed_official 0:51ac1d130fd4 23 */
mbed_official 0:51ac1d130fd4 24
mbed_official 0:51ac1d130fd4 25 #ifndef VJ_H
mbed_official 0:51ac1d130fd4 26 #define VJ_H
mbed_official 0:51ac1d130fd4 27
mbed_official 0:51ac1d130fd4 28 #include "lwip/ip.h"
mbed_official 0:51ac1d130fd4 29 #include "lwip/tcp_impl.h"
mbed_official 0:51ac1d130fd4 30
mbed_official 0:51ac1d130fd4 31 #define MAX_SLOTS 16 /* must be > 2 and < 256 */
mbed_official 0:51ac1d130fd4 32 #define MAX_HDR 128
mbed_official 0:51ac1d130fd4 33
mbed_official 0:51ac1d130fd4 34 /*
mbed_official 0:51ac1d130fd4 35 * Compressed packet format:
mbed_official 0:51ac1d130fd4 36 *
mbed_official 0:51ac1d130fd4 37 * The first octet contains the packet type (top 3 bits), TCP
mbed_official 0:51ac1d130fd4 38 * 'push' bit, and flags that indicate which of the 4 TCP sequence
mbed_official 0:51ac1d130fd4 39 * numbers have changed (bottom 5 bits). The next octet is a
mbed_official 0:51ac1d130fd4 40 * conversation number that associates a saved IP/TCP header with
mbed_official 0:51ac1d130fd4 41 * the compressed packet. The next two octets are the TCP checksum
mbed_official 0:51ac1d130fd4 42 * from the original datagram. The next 0 to 15 octets are
mbed_official 0:51ac1d130fd4 43 * sequence number changes, one change per bit set in the header
mbed_official 0:51ac1d130fd4 44 * (there may be no changes and there are two special cases where
mbed_official 0:51ac1d130fd4 45 * the receiver implicitly knows what changed -- see below).
mbed_official 0:51ac1d130fd4 46 *
mbed_official 0:51ac1d130fd4 47 * There are 5 numbers which can change (they are always inserted
mbed_official 0:51ac1d130fd4 48 * in the following order): TCP urgent pointer, window,
mbed_official 0:51ac1d130fd4 49 * acknowlegement, sequence number and IP ID. (The urgent pointer
mbed_official 0:51ac1d130fd4 50 * is different from the others in that its value is sent, not the
mbed_official 0:51ac1d130fd4 51 * change in value.) Since typical use of SLIP links is biased
mbed_official 0:51ac1d130fd4 52 * toward small packets (see comments on MTU/MSS below), changes
mbed_official 0:51ac1d130fd4 53 * use a variable length coding with one octet for numbers in the
mbed_official 0:51ac1d130fd4 54 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
mbed_official 0:51ac1d130fd4 55 * range 256 - 65535 or 0. (If the change in sequence number or
mbed_official 0:51ac1d130fd4 56 * ack is more than 65535, an uncompressed packet is sent.)
mbed_official 0:51ac1d130fd4 57 */
mbed_official 0:51ac1d130fd4 58
mbed_official 0:51ac1d130fd4 59 /*
mbed_official 0:51ac1d130fd4 60 * Packet types (must not conflict with IP protocol version)
mbed_official 0:51ac1d130fd4 61 *
mbed_official 0:51ac1d130fd4 62 * The top nibble of the first octet is the packet type. There are
mbed_official 0:51ac1d130fd4 63 * three possible types: IP (not proto TCP or tcp with one of the
mbed_official 0:51ac1d130fd4 64 * control flags set); uncompressed TCP (a normal IP/TCP packet but
mbed_official 0:51ac1d130fd4 65 * with the 8-bit protocol field replaced by an 8-bit connection id --
mbed_official 0:51ac1d130fd4 66 * this type of packet syncs the sender & receiver); and compressed
mbed_official 0:51ac1d130fd4 67 * TCP (described above).
mbed_official 0:51ac1d130fd4 68 *
mbed_official 0:51ac1d130fd4 69 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
mbed_official 0:51ac1d130fd4 70 * is logically part of the 4-bit "changes" field that follows. Top
mbed_official 0:51ac1d130fd4 71 * three bits are actual packet type. For backward compatibility
mbed_official 0:51ac1d130fd4 72 * and in the interest of conserving bits, numbers are chosen so the
mbed_official 0:51ac1d130fd4 73 * IP protocol version number (4) which normally appears in this nibble
mbed_official 0:51ac1d130fd4 74 * means "IP packet".
mbed_official 0:51ac1d130fd4 75 */
mbed_official 0:51ac1d130fd4 76
mbed_official 0:51ac1d130fd4 77 /* packet types */
mbed_official 0:51ac1d130fd4 78 #define TYPE_IP 0x40
mbed_official 0:51ac1d130fd4 79 #define TYPE_UNCOMPRESSED_TCP 0x70
mbed_official 0:51ac1d130fd4 80 #define TYPE_COMPRESSED_TCP 0x80
mbed_official 0:51ac1d130fd4 81 #define TYPE_ERROR 0x00
mbed_official 0:51ac1d130fd4 82
mbed_official 0:51ac1d130fd4 83 /* Bits in first octet of compressed packet */
mbed_official 0:51ac1d130fd4 84 #define NEW_C 0x40 /* flag bits for what changed in a packet */
mbed_official 0:51ac1d130fd4 85 #define NEW_I 0x20
mbed_official 0:51ac1d130fd4 86 #define NEW_S 0x08
mbed_official 0:51ac1d130fd4 87 #define NEW_A 0x04
mbed_official 0:51ac1d130fd4 88 #define NEW_W 0x02
mbed_official 0:51ac1d130fd4 89 #define NEW_U 0x01
mbed_official 0:51ac1d130fd4 90
mbed_official 0:51ac1d130fd4 91 /* reserved, special-case values of above */
mbed_official 0:51ac1d130fd4 92 #define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */
mbed_official 0:51ac1d130fd4 93 #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */
mbed_official 0:51ac1d130fd4 94 #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
mbed_official 0:51ac1d130fd4 95
mbed_official 0:51ac1d130fd4 96 #define TCP_PUSH_BIT 0x10
mbed_official 0:51ac1d130fd4 97
mbed_official 0:51ac1d130fd4 98
mbed_official 0:51ac1d130fd4 99 /*
mbed_official 0:51ac1d130fd4 100 * "state" data for each active tcp conversation on the wire. This is
mbed_official 0:51ac1d130fd4 101 * basically a copy of the entire IP/TCP header from the last packet
mbed_official 0:51ac1d130fd4 102 * we saw from the conversation together with a small identifier
mbed_official 0:51ac1d130fd4 103 * the transmit & receive ends of the line use to locate saved header.
mbed_official 0:51ac1d130fd4 104 */
mbed_official 0:51ac1d130fd4 105 struct cstate {
mbed_official 0:51ac1d130fd4 106 struct cstate *cs_next; /* next most recently used state (xmit only) */
mbed_official 0:51ac1d130fd4 107 u_short cs_hlen; /* size of hdr (receive only) */
mbed_official 0:51ac1d130fd4 108 u_char cs_id; /* connection # associated with this state */
mbed_official 0:51ac1d130fd4 109 u_char cs_filler;
mbed_official 0:51ac1d130fd4 110 union {
mbed_official 0:51ac1d130fd4 111 char csu_hdr[MAX_HDR];
mbed_official 0:51ac1d130fd4 112 struct ip_hdr csu_ip; /* ip/tcp hdr from most recent packet */
mbed_official 0:51ac1d130fd4 113 } vjcs_u;
mbed_official 0:51ac1d130fd4 114 };
mbed_official 0:51ac1d130fd4 115 #define cs_ip vjcs_u.csu_ip
mbed_official 0:51ac1d130fd4 116 #define cs_hdr vjcs_u.csu_hdr
mbed_official 0:51ac1d130fd4 117
mbed_official 0:51ac1d130fd4 118
mbed_official 0:51ac1d130fd4 119 struct vjstat {
mbed_official 0:51ac1d130fd4 120 unsigned long vjs_packets; /* outbound packets */
mbed_official 0:51ac1d130fd4 121 unsigned long vjs_compressed; /* outbound compressed packets */
mbed_official 0:51ac1d130fd4 122 unsigned long vjs_searches; /* searches for connection state */
mbed_official 0:51ac1d130fd4 123 unsigned long vjs_misses; /* times couldn't find conn. state */
mbed_official 0:51ac1d130fd4 124 unsigned long vjs_uncompressedin; /* inbound uncompressed packets */
mbed_official 0:51ac1d130fd4 125 unsigned long vjs_compressedin; /* inbound compressed packets */
mbed_official 0:51ac1d130fd4 126 unsigned long vjs_errorin; /* inbound unknown type packets */
mbed_official 0:51ac1d130fd4 127 unsigned long vjs_tossed; /* inbound packets tossed because of error */
mbed_official 0:51ac1d130fd4 128 };
mbed_official 0:51ac1d130fd4 129
mbed_official 0:51ac1d130fd4 130 /*
mbed_official 0:51ac1d130fd4 131 * all the state data for one serial line (we need one of these per line).
mbed_official 0:51ac1d130fd4 132 */
mbed_official 0:51ac1d130fd4 133 struct vjcompress {
mbed_official 0:51ac1d130fd4 134 struct cstate *last_cs; /* most recently used tstate */
mbed_official 0:51ac1d130fd4 135 u_char last_recv; /* last rcvd conn. id */
mbed_official 0:51ac1d130fd4 136 u_char last_xmit; /* last sent conn. id */
mbed_official 0:51ac1d130fd4 137 u_short flags;
mbed_official 0:51ac1d130fd4 138 u_char maxSlotIndex;
mbed_official 0:51ac1d130fd4 139 u_char compressSlot; /* Flag indicating OK to compress slot ID. */
mbed_official 0:51ac1d130fd4 140 #if LINK_STATS
mbed_official 0:51ac1d130fd4 141 struct vjstat stats;
mbed_official 0:51ac1d130fd4 142 #endif
mbed_official 0:51ac1d130fd4 143 struct cstate tstate[MAX_SLOTS]; /* xmit connection states */
mbed_official 0:51ac1d130fd4 144 struct cstate rstate[MAX_SLOTS]; /* receive connection states */
mbed_official 0:51ac1d130fd4 145 };
mbed_official 0:51ac1d130fd4 146
mbed_official 0:51ac1d130fd4 147 /* flag values */
mbed_official 0:51ac1d130fd4 148 #define VJF_TOSS 1U /* tossing rcvd frames because of input err */
mbed_official 0:51ac1d130fd4 149
mbed_official 0:51ac1d130fd4 150 extern void vj_compress_init (struct vjcompress *comp);
mbed_official 0:51ac1d130fd4 151 extern u_int vj_compress_tcp (struct vjcompress *comp, struct pbuf *pb);
mbed_official 0:51ac1d130fd4 152 extern void vj_uncompress_err (struct vjcompress *comp);
mbed_official 0:51ac1d130fd4 153 extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
mbed_official 0:51ac1d130fd4 154 extern int vj_uncompress_tcp (struct pbuf **nb, struct vjcompress *comp);
mbed_official 0:51ac1d130fd4 155
mbed_official 0:51ac1d130fd4 156 #endif /* VJ_H */