Dependencies:   mbed

Dependents:   TCP

Committer:
slowness
Date:
Tue Sep 06 18:05:46 2011 +0000
Revision:
0:58c3d014a4e7

        

Who changed what in which revision?

UserRevisionLine numberNew contents of line
slowness 0:58c3d014a4e7 1 /*
slowness 0:58c3d014a4e7 2 * Definitions for tcp compression routines.
slowness 0:58c3d014a4e7 3 *
slowness 0:58c3d014a4e7 4 * $Id: vj.h,v 1.7 2010/02/22 17:52:09 goldsimon Exp $
slowness 0:58c3d014a4e7 5 *
slowness 0:58c3d014a4e7 6 * Copyright (c) 1989 Regents of the University of California.
slowness 0:58c3d014a4e7 7 * All rights reserved.
slowness 0:58c3d014a4e7 8 *
slowness 0:58c3d014a4e7 9 * Redistribution and use in source and binary forms are permitted
slowness 0:58c3d014a4e7 10 * provided that the above copyright notice and this paragraph are
slowness 0:58c3d014a4e7 11 * duplicated in all such forms and that any documentation,
slowness 0:58c3d014a4e7 12 * advertising materials, and other materials related to such
slowness 0:58c3d014a4e7 13 * distribution and use acknowledge that the software was developed
slowness 0:58c3d014a4e7 14 * by the University of California, Berkeley. The name of the
slowness 0:58c3d014a4e7 15 * University may not be used to endorse or promote products derived
slowness 0:58c3d014a4e7 16 * from this software without specific prior written permission.
slowness 0:58c3d014a4e7 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
slowness 0:58c3d014a4e7 18 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
slowness 0:58c3d014a4e7 19 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
slowness 0:58c3d014a4e7 20 *
slowness 0:58c3d014a4e7 21 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
slowness 0:58c3d014a4e7 22 * - Initial distribution.
slowness 0:58c3d014a4e7 23 */
slowness 0:58c3d014a4e7 24
slowness 0:58c3d014a4e7 25 #ifndef VJ_H
slowness 0:58c3d014a4e7 26 #define VJ_H
slowness 0:58c3d014a4e7 27
slowness 0:58c3d014a4e7 28 #include "lwip/ip.h"
slowness 0:58c3d014a4e7 29 #include "lwip/tcp_impl.h"
slowness 0:58c3d014a4e7 30
slowness 0:58c3d014a4e7 31 #define MAX_SLOTS 16 /* must be > 2 and < 256 */
slowness 0:58c3d014a4e7 32 #define MAX_HDR 128
slowness 0:58c3d014a4e7 33
slowness 0:58c3d014a4e7 34 /*
slowness 0:58c3d014a4e7 35 * Compressed packet format:
slowness 0:58c3d014a4e7 36 *
slowness 0:58c3d014a4e7 37 * The first octet contains the packet type (top 3 bits), TCP
slowness 0:58c3d014a4e7 38 * 'push' bit, and flags that indicate which of the 4 TCP sequence
slowness 0:58c3d014a4e7 39 * numbers have changed (bottom 5 bits). The next octet is a
slowness 0:58c3d014a4e7 40 * conversation number that associates a saved IP/TCP header with
slowness 0:58c3d014a4e7 41 * the compressed packet. The next two octets are the TCP checksum
slowness 0:58c3d014a4e7 42 * from the original datagram. The next 0 to 15 octets are
slowness 0:58c3d014a4e7 43 * sequence number changes, one change per bit set in the header
slowness 0:58c3d014a4e7 44 * (there may be no changes and there are two special cases where
slowness 0:58c3d014a4e7 45 * the receiver implicitly knows what changed -- see below).
slowness 0:58c3d014a4e7 46 *
slowness 0:58c3d014a4e7 47 * There are 5 numbers which can change (they are always inserted
slowness 0:58c3d014a4e7 48 * in the following order): TCP urgent pointer, window,
slowness 0:58c3d014a4e7 49 * acknowlegement, sequence number and IP ID. (The urgent pointer
slowness 0:58c3d014a4e7 50 * is different from the others in that its value is sent, not the
slowness 0:58c3d014a4e7 51 * change in value.) Since typical use of SLIP links is biased
slowness 0:58c3d014a4e7 52 * toward small packets (see comments on MTU/MSS below), changes
slowness 0:58c3d014a4e7 53 * use a variable length coding with one octet for numbers in the
slowness 0:58c3d014a4e7 54 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
slowness 0:58c3d014a4e7 55 * range 256 - 65535 or 0. (If the change in sequence number or
slowness 0:58c3d014a4e7 56 * ack is more than 65535, an uncompressed packet is sent.)
slowness 0:58c3d014a4e7 57 */
slowness 0:58c3d014a4e7 58
slowness 0:58c3d014a4e7 59 /*
slowness 0:58c3d014a4e7 60 * Packet types (must not conflict with IP protocol version)
slowness 0:58c3d014a4e7 61 *
slowness 0:58c3d014a4e7 62 * The top nibble of the first octet is the packet type. There are
slowness 0:58c3d014a4e7 63 * three possible types: IP (not proto TCP or tcp with one of the
slowness 0:58c3d014a4e7 64 * control flags set); uncompressed TCP (a normal IP/TCP packet but
slowness 0:58c3d014a4e7 65 * with the 8-bit protocol field replaced by an 8-bit connection id --
slowness 0:58c3d014a4e7 66 * this type of packet syncs the sender & receiver); and compressed
slowness 0:58c3d014a4e7 67 * TCP (described above).
slowness 0:58c3d014a4e7 68 *
slowness 0:58c3d014a4e7 69 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
slowness 0:58c3d014a4e7 70 * is logically part of the 4-bit "changes" field that follows. Top
slowness 0:58c3d014a4e7 71 * three bits are actual packet type. For backward compatibility
slowness 0:58c3d014a4e7 72 * and in the interest of conserving bits, numbers are chosen so the
slowness 0:58c3d014a4e7 73 * IP protocol version number (4) which normally appears in this nibble
slowness 0:58c3d014a4e7 74 * means "IP packet".
slowness 0:58c3d014a4e7 75 */
slowness 0:58c3d014a4e7 76
slowness 0:58c3d014a4e7 77 /* packet types */
slowness 0:58c3d014a4e7 78 #define TYPE_IP 0x40
slowness 0:58c3d014a4e7 79 #define TYPE_UNCOMPRESSED_TCP 0x70
slowness 0:58c3d014a4e7 80 #define TYPE_COMPRESSED_TCP 0x80
slowness 0:58c3d014a4e7 81 #define TYPE_ERROR 0x00
slowness 0:58c3d014a4e7 82
slowness 0:58c3d014a4e7 83 /* Bits in first octet of compressed packet */
slowness 0:58c3d014a4e7 84 #define NEW_C 0x40 /* flag bits for what changed in a packet */
slowness 0:58c3d014a4e7 85 #define NEW_I 0x20
slowness 0:58c3d014a4e7 86 #define NEW_S 0x08
slowness 0:58c3d014a4e7 87 #define NEW_A 0x04
slowness 0:58c3d014a4e7 88 #define NEW_W 0x02
slowness 0:58c3d014a4e7 89 #define NEW_U 0x01
slowness 0:58c3d014a4e7 90
slowness 0:58c3d014a4e7 91 /* reserved, special-case values of above */
slowness 0:58c3d014a4e7 92 #define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */
slowness 0:58c3d014a4e7 93 #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */
slowness 0:58c3d014a4e7 94 #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
slowness 0:58c3d014a4e7 95
slowness 0:58c3d014a4e7 96 #define TCP_PUSH_BIT 0x10
slowness 0:58c3d014a4e7 97
slowness 0:58c3d014a4e7 98
slowness 0:58c3d014a4e7 99 /*
slowness 0:58c3d014a4e7 100 * "state" data for each active tcp conversation on the wire. This is
slowness 0:58c3d014a4e7 101 * basically a copy of the entire IP/TCP header from the last packet
slowness 0:58c3d014a4e7 102 * we saw from the conversation together with a small identifier
slowness 0:58c3d014a4e7 103 * the transmit & receive ends of the line use to locate saved header.
slowness 0:58c3d014a4e7 104 */
slowness 0:58c3d014a4e7 105 struct cstate {
slowness 0:58c3d014a4e7 106 struct cstate *cs_next; /* next most recently used state (xmit only) */
slowness 0:58c3d014a4e7 107 u_short cs_hlen; /* size of hdr (receive only) */
slowness 0:58c3d014a4e7 108 u_char cs_id; /* connection # associated with this state */
slowness 0:58c3d014a4e7 109 u_char cs_filler;
slowness 0:58c3d014a4e7 110 union {
slowness 0:58c3d014a4e7 111 char csu_hdr[MAX_HDR];
slowness 0:58c3d014a4e7 112 struct ip_hdr csu_ip; /* ip/tcp hdr from most recent packet */
slowness 0:58c3d014a4e7 113 } vjcs_u;
slowness 0:58c3d014a4e7 114 };
slowness 0:58c3d014a4e7 115 #define cs_ip vjcs_u.csu_ip
slowness 0:58c3d014a4e7 116 #define cs_hdr vjcs_u.csu_hdr
slowness 0:58c3d014a4e7 117
slowness 0:58c3d014a4e7 118
slowness 0:58c3d014a4e7 119 struct vjstat {
slowness 0:58c3d014a4e7 120 unsigned long vjs_packets; /* outbound packets */
slowness 0:58c3d014a4e7 121 unsigned long vjs_compressed; /* outbound compressed packets */
slowness 0:58c3d014a4e7 122 unsigned long vjs_searches; /* searches for connection state */
slowness 0:58c3d014a4e7 123 unsigned long vjs_misses; /* times couldn't find conn. state */
slowness 0:58c3d014a4e7 124 unsigned long vjs_uncompressedin; /* inbound uncompressed packets */
slowness 0:58c3d014a4e7 125 unsigned long vjs_compressedin; /* inbound compressed packets */
slowness 0:58c3d014a4e7 126 unsigned long vjs_errorin; /* inbound unknown type packets */
slowness 0:58c3d014a4e7 127 unsigned long vjs_tossed; /* inbound packets tossed because of error */
slowness 0:58c3d014a4e7 128 };
slowness 0:58c3d014a4e7 129
slowness 0:58c3d014a4e7 130 /*
slowness 0:58c3d014a4e7 131 * all the state data for one serial line (we need one of these per line).
slowness 0:58c3d014a4e7 132 */
slowness 0:58c3d014a4e7 133 struct vjcompress {
slowness 0:58c3d014a4e7 134 struct cstate *last_cs; /* most recently used tstate */
slowness 0:58c3d014a4e7 135 u_char last_recv; /* last rcvd conn. id */
slowness 0:58c3d014a4e7 136 u_char last_xmit; /* last sent conn. id */
slowness 0:58c3d014a4e7 137 u_short flags;
slowness 0:58c3d014a4e7 138 u_char maxSlotIndex;
slowness 0:58c3d014a4e7 139 u_char compressSlot; /* Flag indicating OK to compress slot ID. */
slowness 0:58c3d014a4e7 140 #if LINK_STATS
slowness 0:58c3d014a4e7 141 struct vjstat stats;
slowness 0:58c3d014a4e7 142 #endif
slowness 0:58c3d014a4e7 143 struct cstate tstate[MAX_SLOTS]; /* xmit connection states */
slowness 0:58c3d014a4e7 144 struct cstate rstate[MAX_SLOTS]; /* receive connection states */
slowness 0:58c3d014a4e7 145 };
slowness 0:58c3d014a4e7 146
slowness 0:58c3d014a4e7 147 /* flag values */
slowness 0:58c3d014a4e7 148 #define VJF_TOSS 1U /* tossing rcvd frames because of input err */
slowness 0:58c3d014a4e7 149
slowness 0:58c3d014a4e7 150 extern void vj_compress_init (struct vjcompress *comp);
slowness 0:58c3d014a4e7 151 extern u_int vj_compress_tcp (struct vjcompress *comp, struct pbuf *pb);
slowness 0:58c3d014a4e7 152 extern void vj_uncompress_err (struct vjcompress *comp);
slowness 0:58c3d014a4e7 153 extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
slowness 0:58c3d014a4e7 154 extern int vj_uncompress_tcp (struct pbuf **nb, struct vjcompress *comp);
slowness 0:58c3d014a4e7 155
slowness 0:58c3d014a4e7 156 #endif /* VJ_H */