BadVPN – Blame information for rev 1
?pathlinks?
Rev | Author | Line No. | Line |
---|---|---|---|
1 | office | 1 | /* |
2 | * Definitions for tcp compression routines. |
||
3 | * |
||
4 | * $Id: vj.h,v 1.7 2010/02/22 17:52:09 goldsimon 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 | #include "netif/ppp/ppp_opts.h" |
||
26 | #if PPP_SUPPORT && VJ_SUPPORT /* don't build if not configured for use in lwipopts.h */ |
||
27 | |||
28 | #ifndef VJ_H |
||
29 | #define VJ_H |
||
30 | |||
31 | #include "lwip/ip.h" |
||
32 | #include "lwip/priv/tcp_priv.h" |
||
33 | |||
34 | #define MAX_SLOTS 16 /* must be > 2 and < 256 */ |
||
35 | #define MAX_HDR 128 |
||
36 | |||
37 | /* |
||
38 | * Compressed packet format: |
||
39 | * |
||
40 | * The first octet contains the packet type (top 3 bits), TCP |
||
41 | * 'push' bit, and flags that indicate which of the 4 TCP sequence |
||
42 | * numbers have changed (bottom 5 bits). The next octet is a |
||
43 | * conversation number that associates a saved IP/TCP header with |
||
44 | * the compressed packet. The next two octets are the TCP checksum |
||
45 | * from the original datagram. The next 0 to 15 octets are |
||
46 | * sequence number changes, one change per bit set in the header |
||
47 | * (there may be no changes and there are two special cases where |
||
48 | * the receiver implicitly knows what changed -- see below). |
||
49 | * |
||
50 | * There are 5 numbers which can change (they are always inserted |
||
51 | * in the following order): TCP urgent pointer, window, |
||
52 | * acknowlegement, sequence number and IP ID. (The urgent pointer |
||
53 | * is different from the others in that its value is sent, not the |
||
54 | * change in value.) Since typical use of SLIP links is biased |
||
55 | * toward small packets (see comments on MTU/MSS below), changes |
||
56 | * use a variable length coding with one octet for numbers in the |
||
57 | * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the |
||
58 | * range 256 - 65535 or 0. (If the change in sequence number or |
||
59 | * ack is more than 65535, an uncompressed packet is sent.) |
||
60 | */ |
||
61 | |||
62 | /* |
||
63 | * Packet types (must not conflict with IP protocol version) |
||
64 | * |
||
65 | * The top nibble of the first octet is the packet type. There are |
||
66 | * three possible types: IP (not proto TCP or tcp with one of the |
||
67 | * control flags set); uncompressed TCP (a normal IP/TCP packet but |
||
68 | * with the 8-bit protocol field replaced by an 8-bit connection id -- |
||
69 | * this type of packet syncs the sender & receiver); and compressed |
||
70 | * TCP (described above). |
||
71 | * |
||
72 | * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and |
||
73 | * is logically part of the 4-bit "changes" field that follows. Top |
||
74 | * three bits are actual packet type. For backward compatibility |
||
75 | * and in the interest of conserving bits, numbers are chosen so the |
||
76 | * IP protocol version number (4) which normally appears in this nibble |
||
77 | * means "IP packet". |
||
78 | */ |
||
79 | |||
80 | /* packet types */ |
||
81 | #define TYPE_IP 0x40 |
||
82 | #define TYPE_UNCOMPRESSED_TCP 0x70 |
||
83 | #define TYPE_COMPRESSED_TCP 0x80 |
||
84 | #define TYPE_ERROR 0x00 |
||
85 | |||
86 | /* Bits in first octet of compressed packet */ |
||
87 | #define NEW_C 0x40 /* flag bits for what changed in a packet */ |
||
88 | #define NEW_I 0x20 |
||
89 | #define NEW_S 0x08 |
||
90 | #define NEW_A 0x04 |
||
91 | #define NEW_W 0x02 |
||
92 | #define NEW_U 0x01 |
||
93 | |||
94 | /* reserved, special-case values of above */ |
||
95 | #define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */ |
||
96 | #define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */ |
||
97 | #define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U) |
||
98 | |||
99 | #define TCP_PUSH_BIT 0x10 |
||
100 | |||
101 | |||
102 | /* |
||
103 | * "state" data for each active tcp conversation on the wire. This is |
||
104 | * basically a copy of the entire IP/TCP header from the last packet |
||
105 | * we saw from the conversation together with a small identifier |
||
106 | * the transmit & receive ends of the line use to locate saved header. |
||
107 | */ |
||
108 | struct cstate { |
||
109 | struct cstate *cs_next; /* next most recently used state (xmit only) */ |
||
110 | u16_t cs_hlen; /* size of hdr (receive only) */ |
||
111 | u8_t cs_id; /* connection # associated with this state */ |
||
112 | u8_t cs_filler; |
||
113 | union { |
||
114 | char csu_hdr[MAX_HDR]; |
||
115 | struct ip_hdr csu_ip; /* ip/tcp hdr from most recent packet */ |
||
116 | } vjcs_u; |
||
117 | }; |
||
118 | #define cs_ip vjcs_u.csu_ip |
||
119 | #define cs_hdr vjcs_u.csu_hdr |
||
120 | |||
121 | |||
122 | struct vjstat { |
||
123 | u32_t vjs_packets; /* outbound packets */ |
||
124 | u32_t vjs_compressed; /* outbound compressed packets */ |
||
125 | u32_t vjs_searches; /* searches for connection state */ |
||
126 | u32_t vjs_misses; /* times couldn't find conn. state */ |
||
127 | u32_t vjs_uncompressedin; /* inbound uncompressed packets */ |
||
128 | u32_t vjs_compressedin; /* inbound compressed packets */ |
||
129 | u32_t vjs_errorin; /* inbound unknown type packets */ |
||
130 | u32_t vjs_tossed; /* inbound packets tossed because of error */ |
||
131 | }; |
||
132 | |||
133 | /* |
||
134 | * all the state data for one serial line (we need one of these per line). |
||
135 | */ |
||
136 | struct vjcompress { |
||
137 | struct cstate *last_cs; /* most recently used tstate */ |
||
138 | u8_t last_recv; /* last rcvd conn. id */ |
||
139 | u8_t last_xmit; /* last sent conn. id */ |
||
140 | u16_t flags; |
||
141 | u8_t maxSlotIndex; |
||
142 | u8_t compressSlot; /* Flag indicating OK to compress slot ID. */ |
||
143 | #if LINK_STATS |
||
144 | struct vjstat stats; |
||
145 | #endif |
||
146 | struct cstate tstate[MAX_SLOTS]; /* xmit connection states */ |
||
147 | struct cstate rstate[MAX_SLOTS]; /* receive connection states */ |
||
148 | }; |
||
149 | |||
150 | /* flag values */ |
||
151 | #define VJF_TOSS 1U /* tossing rcvd frames because of input err */ |
||
152 | |||
153 | extern void vj_compress_init (struct vjcompress *comp); |
||
154 | extern u8_t vj_compress_tcp (struct vjcompress *comp, struct pbuf **pb); |
||
155 | extern void vj_uncompress_err (struct vjcompress *comp); |
||
156 | extern int vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp); |
||
157 | extern int vj_uncompress_tcp (struct pbuf **nb, struct vjcompress *comp); |
||
158 | |||
159 | #endif /* VJ_H */ |
||
160 | |||
161 | #endif /* PPP_SUPPORT && VJ_SUPPORT */ |