root/webserver/example/freeRTOS/Demo/Common/ethernet/lwIP/netif/ppp/vj.h

Revision 14, 6.1 kB (checked in by phil, 15 years ago)

added unmodified FreeRTOS package V5.4.1 with only web srv demo source for LPC2368 for CrossWorks?

Line 
1 /*
2  * Definitions for tcp compression routines.
3  *
4  * $Id: vj.h,v 1.4 2004/02/07 00:30:03 likewise Exp $
5  *
6  * Copyright (c) 1989 Regents of the University of California.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms are permitted
10  * provided that the above copyright notice and this paragraph are
11  * duplicated in all such forms and that any documentation,
12  * advertising materials, and other materials related to such
13  * distribution and use acknowledge that the software was developed
14  * by the University of California, Berkeley.  The name of the
15  * University may not be used to endorse or promote products derived
16  * from this software without specific prior written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
19  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  *      Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
22  *      - Initial distribution.
23  */
24
25 #ifndef VJ_H
26 #define VJ_H
27
28 #include "vjbsdhdr.h"
29
30 #define MAX_SLOTS       16                      /* must be > 2 and < 256 */
31 #define MAX_HDR         128
32
33 /*
34  * Compressed packet format:
35  *
36  * The first octet contains the packet type (top 3 bits), TCP
37  * 'push' bit, and flags that indicate which of the 4 TCP sequence
38  * numbers have changed (bottom 5 bits).  The next octet is a
39  * conversation number that associates a saved IP/TCP header with
40  * the compressed packet.  The next two octets are the TCP checksum
41  * from the original datagram.  The next 0 to 15 octets are
42  * sequence number changes, one change per bit set in the header
43  * (there may be no changes and there are two special cases where
44  * the receiver implicitly knows what changed -- see below).
45  *
46  * There are 5 numbers which can change (they are always inserted
47  * in the following order): TCP urgent pointer, window,
48  * acknowlegement, sequence number and IP ID.  (The urgent pointer
49  * is different from the others in that its value is sent, not the
50  * change in value.)  Since typical use of SLIP links is biased
51  * toward small packets (see comments on MTU/MSS below), changes
52  * use a variable length coding with one octet for numbers in the
53  * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
54  * range 256 - 65535 or 0.  (If the change in sequence number or
55  * ack is more than 65535, an uncompressed packet is sent.)
56  */
57
58 /*
59  * Packet types (must not conflict with IP protocol version)
60  *
61  * The top nibble of the first octet is the packet type.  There are
62  * three possible types: IP (not proto TCP or tcp with one of the
63  * control flags set); uncompressed TCP (a normal IP/TCP packet but
64  * with the 8-bit protocol field replaced by an 8-bit connection id --
65  * this type of packet syncs the sender & receiver); and compressed
66  * TCP (described above).
67  *
68  * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
69  * is logically part of the 4-bit "changes" field that follows.  Top
70  * three bits are actual packet type.  For backward compatibility
71  * and in the interest of conserving bits, numbers are chosen so the
72  * IP protocol version number (4) which normally appears in this nibble
73  * means "IP packet".
74  */
75
76 /* packet types */
77 #define TYPE_IP 0x40
78 #define TYPE_UNCOMPRESSED_TCP 0x70
79 #define TYPE_COMPRESSED_TCP 0x80
80 #define TYPE_ERROR 0x00
81
82 /* Bits in first octet of compressed packet */
83 #define NEW_C   0x40    /* flag bits for what changed in a packet */
84 #define NEW_I   0x20
85 #define NEW_S   0x08
86 #define NEW_A   0x04
87 #define NEW_W   0x02
88 #define NEW_U   0x01
89
90 /* reserved, special-case values of above */
91 #define SPECIAL_I (NEW_S|NEW_W|NEW_U)           /* echoed interactive traffic */
92 #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U)     /* unidirectional data */
93 #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
94
95 #define TCP_PUSH_BIT 0x10
96
97
98 /*
99  * "state" data for each active tcp conversation on the wire.  This is
100  * basically a copy of the entire IP/TCP header from the last packet
101  * we saw from the conversation together with a small identifier
102  * the transmit & receive ends of the line use to locate saved header.
103  */
104 struct cstate {
105     struct cstate *cs_next;     /* next most recently used state (xmit only) */
106     u_short cs_hlen;            /* size of hdr (receive only) */
107     u_char cs_id;                       /* connection # associated with this state */
108     u_char cs_filler;
109     union {
110                 char csu_hdr[MAX_HDR];
111                 struct ip csu_ip;       /* ip/tcp hdr from most recent packet */
112     } vjcs_u;
113 };
114 #define cs_ip vjcs_u.csu_ip
115 #define cs_hdr vjcs_u.csu_hdr
116
117
118 struct vjstat {
119     unsigned long vjs_packets;                  /* outbound packets */
120     unsigned long vjs_compressed;               /* outbound compressed packets */
121     unsigned long vjs_searches;                 /* searches for connection state */
122     unsigned long vjs_misses;                   /* times couldn't find conn. state */
123     unsigned long vjs_uncompressedin;   /* inbound uncompressed packets */
124     unsigned long vjs_compressedin;             /* inbound compressed packets */
125     unsigned long vjs_errorin;                  /* inbound unknown type packets */
126     unsigned long vjs_tossed;                   /* inbound packets tossed because of error */
127 };
128
129 /*
130  * all the state data for one serial line (we need one of these per line).
131  */
132 struct vjcompress {
133     struct cstate *last_cs;     /* most recently used tstate */
134     u_char last_recv;           /* last rcvd conn. id */
135     u_char last_xmit;           /* last sent conn. id */
136     u_short flags;
137     u_char maxSlotIndex;
138     u_char compressSlot;        /* Flag indicating OK to compress slot ID. */
139 #if LINK_STATS
140     struct vjstat stats;
141 #endif
142     struct cstate tstate[MAX_SLOTS];    /* xmit connection states */
143     struct cstate rstate[MAX_SLOTS];    /* receive connection states */
144 };
145
146 /* flag values */
147 #define VJF_TOSS 1U             /* tossing rcvd frames because of input err */
148
149 extern void  vj_compress_init (struct vjcompress *comp);
150 extern u_int vj_compress_tcp (struct vjcompress *comp, struct pbuf *pb);
151 extern void  vj_uncompress_err (struct vjcompress *comp);
152 extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
153 extern int vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp);
154
155 #endif /* VJ_H */
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