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Diffstat (limited to 'include/net/vjcompress.h')
| -rw-r--r-- | include/net/vjcompress.h | 144 |
1 files changed, 0 insertions, 144 deletions
diff --git a/include/net/vjcompress.h b/include/net/vjcompress.h deleted file mode 100644 index c70dda3d0..000000000 --- a/include/net/vjcompress.h +++ /dev/null @@ -1,144 +0,0 @@ -/* - * Definitions for tcp compression routines. - * - * $Id: vjcompress.h,v 1.3 2001/09/27 05:21:12 andersen Exp $ - * - * Copyright (c) 1989 Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms are permitted - * provided that the above copyright notice and this paragraph are - * duplicated in all such forms and that any documentation, - * advertising materials, and other materials related to such - * distribution and use acknowledge that the software was developed - * by the University of California, Berkeley. The name of the - * University may not be used to endorse or promote products derived - * from this software without specific prior written permission. - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED - * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. - * - * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: - * - Initial distribution. - */ - -#ifndef _VJCOMPRESS_H_ -#define _VJCOMPRESS_H_ - -#define MAX_STATES 16 /* must be > 2 and < 256 */ -#define MAX_HDR 128 - -/* - * Compressed packet format: - * - * The first octet contains the packet type (top 3 bits), TCP - * 'push' bit, and flags that indicate which of the 4 TCP sequence - * numbers have changed (bottom 5 bits). The next octet is a - * conversation number that associates a saved IP/TCP header with - * the compressed packet. The next two octets are the TCP checksum - * from the original datagram. The next 0 to 15 octets are - * sequence number changes, one change per bit set in the header - * (there may be no changes and there are two special cases where - * the receiver implicitly knows what changed -- see below). - * - * There are 5 numbers which can change (they are always inserted - * in the following order): TCP urgent pointer, window, - * acknowlegement, sequence number and IP ID. (The urgent pointer - * is different from the others in that its value is sent, not the - * change in value.) Since typical use of SLIP links is biased - * toward small packets (see comments on MTU/MSS below), changes - * use a variable length coding with one octet for numbers in the - * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the - * range 256 - 65535 or 0. (If the change in sequence number or - * ack is more than 65535, an uncompressed packet is sent.) - */ - -/* - * Packet types (must not conflict with IP protocol version) - * - * The top nibble of the first octet is the packet type. There are - * three possible types: IP (not proto TCP or tcp with one of the - * control flags set); uncompressed TCP (a normal IP/TCP packet but - * with the 8-bit protocol field replaced by an 8-bit connection id -- - * this type of packet syncs the sender & receiver); and compressed - * TCP (described above). - * - * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and - * is logically part of the 4-bit "changes" field that follows. Top - * three bits are actual packet type. For backward compatibility - * and in the interest of conserving bits, numbers are chosen so the - * IP protocol version number (4) which normally appears in this nibble - * means "IP packet". - */ - -/* packet types */ -#define TYPE_IP 0x40 -#define TYPE_UNCOMPRESSED_TCP 0x70 -#define TYPE_COMPRESSED_TCP 0x80 -#define TYPE_ERROR 0x00 - -/* Bits in first octet of compressed packet */ -#define NEW_C 0x40 /* flag bits for what changed in a packet */ -#define NEW_I 0x20 -#define NEW_S 0x08 -#define NEW_A 0x04 -#define NEW_W 0x02 -#define NEW_U 0x01 - -/* reserved, special-case values of above */ -#define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */ -#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */ -#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U) - -#define TCP_PUSH_BIT 0x10 - - -/* - * "state" data for each active tcp conversation on the wire. This is - * basically a copy of the entire IP/TCP header from the last packet - * we saw from the conversation together with a small identifier - * the transmit & receive ends of the line use to locate saved header. - */ -struct cstate { - struct cstate *cs_next; /* next most recently used state (xmit only) */ - u_short cs_hlen; /* size of hdr (receive only) */ - u_char cs_id; /* connection # associated with this state */ - u_char cs_filler; - union { - char csu_hdr[MAX_HDR]; - struct ip csu_ip; /* ip/tcp hdr from most recent packet */ - } vjcs_u; -}; -#define cs_ip vjcs_u.csu_ip -#define cs_hdr vjcs_u.csu_hdr - -/* - * all the state data for one serial line (we need one of these per line). - */ -struct vjcompress { - struct cstate *last_cs; /* most recently used tstate */ - u_char last_recv; /* last rcvd conn. id */ - u_char last_xmit; /* last sent conn. id */ - u_short flags; -#ifndef VJ_NO_STATS - struct vjstat stats; -#endif - struct cstate tstate[MAX_STATES]; /* xmit connection states */ - struct cstate rstate[MAX_STATES]; /* receive connection states */ -}; - -/* flag values */ -#define VJF_TOSS 1 /* tossing rcvd frames because of input err */ - -extern void vj_compress_init __P((struct vjcompress *comp, int max_state)); -extern u_int vj_compress_tcp __P((struct ip *ip, u_int mlen, - struct vjcompress *comp, int compress_cid_flag, - u_char **vjhdrp)); -extern void vj_uncompress_err __P((struct vjcompress *comp)); -extern int vj_uncompress_uncomp __P((u_char *buf, int buflen, - struct vjcompress *comp)); -extern int vj_uncompress_tcp __P((u_char *buf, int buflen, int total_len, - struct vjcompress *comp, u_char **hdrp, - u_int *hlenp)); - -#endif /* _VJCOMPRESS_H_ */ |