[linux.git] / include / net / slhc_vj.h

#ifndef _SLHC_H
#define _SLHC_H
/*
 * Definitions for tcp compression routines.
 *
 * $Header: slcompress.h,v 1.10 89/12/31 08:53:02 van 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 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	Van Jacobson ([email protected]), Dec 31, 1989:
 *	- Initial distribution.
 *
 *
 * modified for KA9Q Internet Software Package by
 * Katie Stevens ([email protected])
 * University of California, Davis
 * Computing Services
 *	- 01-31-90	initial adaptation
 *
 *	- Feb 1991	[email protected]
 *			variable number of conversation slots
 *			allow zero or one slots
 *			separate routines
 *			status display
 */

/*
 * 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,
 * acknowledgment, 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".
 */


#include <linux/ip.h>
#include <linux/tcp.h>

/* SLIP compression masks for len/vers byte */
#define SL_TYPE_IP 0x40
#define SL_TYPE_UNCOMPRESSED_TCP 0x70
#define SL_TYPE_COMPRESSED_TCP 0x80
#define SL_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

/*
 * data type and sizes conversion assumptions:
 *
 *	VJ code		KA9Q style	generic
 *	u_char		byte_t		unsigned char	 8 bits
 *	u_short		int16		unsigned short	16 bits
 *	u_int		int16		unsigned short	16 bits
 *	u_long		unsigned long	unsigned long	32 bits
 *	int		int32		long		32 bits
 */

typedef __u8 byte_t;
typedef __u32 int32;

/*
 * "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 {
	byte_t	cs_this;	/* connection id number (xmit) */
	struct cstate *next;	/* next in ring (xmit) */
	struct iphdr cs_ip;	/* ip/tcp hdr from most recent packet */
	struct tcphdr cs_tcp;
	unsigned char cs_ipopt[64];
	unsigned char cs_tcpopt[64];
	int cs_hsize;
};
#define NULLSLSTATE	(struct cstate *)0

/*
 * all the state data for one serial line (we need one of these per line).
 */
struct slcompress {
	struct cstate *tstate;	/* transmit connection states (array)*/
	struct cstate *rstate;	/* receive connection states (array)*/

	byte_t tslot_limit;	/* highest transmit slot id (0-l)*/
	byte_t rslot_limit;	/* highest receive slot id (0-l)*/

	byte_t xmit_oldest;	/* oldest xmit in ring */
	byte_t xmit_current;	/* most recent xmit id */
	byte_t recv_current;	/* most recent rcvd id */

	byte_t flags;
#define SLF_TOSS	0x01	/* tossing rcvd frames until id received */

	int32 sls_o_nontcp;	/* outbound non-TCP packets */
	int32 sls_o_tcp;	/* outbound TCP packets */
	int32 sls_o_uncompressed;	/* outbound uncompressed packets */
	int32 sls_o_compressed;	/* outbound compressed packets */
	int32 sls_o_searches;	/* searches for connection state */
	int32 sls_o_misses;	/* times couldn't find conn. state */

	int32 sls_i_uncompressed;	/* inbound uncompressed packets */
	int32 sls_i_compressed;	/* inbound compressed packets */
	int32 sls_i_error;	/* inbound error packets */
	int32 sls_i_tossed;	/* inbound packets tossed because of error */

	int32 sls_i_runt;
	int32 sls_i_badcheck;
};
#define NULLSLCOMPR	(struct slcompress *)0

/* In slhc.c: */
struct slcompress *slhc_init(int rslots, int tslots);
void slhc_free(struct slcompress *comp);

int slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
		  unsigned char *ocp, unsigned char **cpp, int compress_cid);
int slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize);
int slhc_remember(struct slcompress *comp, unsigned char *icp, int isize);
int slhc_toss(struct slcompress *comp);

#endif	/* _SLHC_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _SLHC_H
	2	#define _SLHC_H
	3	/*
	4	* Definitions for tcp compression routines.
	5	*
	6	* $Header: slcompress.h,v 1.10 89/12/31 08:53:02 van Exp $
	7	*
	8	* Copyright (c) 1989 Regents of the University of California.
	9	* All rights reserved.
	10	*
	11	* Redistribution and use in source and binary forms are permitted
	12	* provided that the above copyright notice and this paragraph are
	13	* duplicated in all such forms and that any documentation,
	14	* advertising materials, and other materials related to such
	15	* distribution and use acknowledge that the software was developed
	16	* by the University of California, Berkeley. The name of the
	17	* University may not be used to endorse or promote products derived
	18	* from this software without specific prior written permission.
	19	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	20	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	21	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	22	*
	23	* Van Jacobson ([email protected]), Dec 31, 1989:
	24	* - Initial distribution.
	25	*
	26	*
	27	* modified for KA9Q Internet Software Package by
	28	* Katie Stevens ([email protected])
	29	* University of California, Davis
	30	* Computing Services
	31	* - 01-31-90 initial adaptation
	32	*
	33	* - Feb 1991 [email protected]
	34	* variable number of conversation slots
	35	* allow zero or one slots
	36	* separate routines
	37	* status display
	38	*/
	39
	40	/*
	41	* Compressed packet format:
	42	*
	43	* The first octet contains the packet type (top 3 bits), TCP
	44	* 'push' bit, and flags that indicate which of the 4 TCP sequence
	45	* numbers have changed (bottom 5 bits). The next octet is a
	46	* conversation number that associates a saved IP/TCP header with
	47	* the compressed packet. The next two octets are the TCP checksum
	48	* from the original datagram. The next 0 to 15 octets are
	49	* sequence number changes, one change per bit set in the header
	50	* (there may be no changes and there are two special cases where
	51	* the receiver implicitly knows what changed -- see below).
	52	*
	53	* There are 5 numbers which can change (they are always inserted
	54	* in the following order): TCP urgent pointer, window,
	55	* acknowledgment, sequence number and IP ID. (The urgent pointer
	56	* is different from the others in that its value is sent, not the
	57	* change in value.) Since typical use of SLIP links is biased
	58	* toward small packets (see comments on MTU/MSS below), changes
	59	* use a variable length coding with one octet for numbers in the
	60	* range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
	61	* range 256 - 65535 or 0. (If the change in sequence number or
	62	* ack is more than 65535, an uncompressed packet is sent.)
	63	*/
	64
65	/*
66	* Packet types (must not conflict with IP protocol version)
67	*
68	* The top nibble of the first octet is the packet type. There are
69	* three possible types: IP (not proto TCP or tcp with one of the
70	* control flags set); uncompressed TCP (a normal IP/TCP packet but
71	* with the 8-bit protocol field replaced by an 8-bit connection id --
72	* this type of packet syncs the sender & receiver); and compressed
73	* TCP (described above).
74	*
75	* LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
76	* is logically part of the 4-bit "changes" field that follows. Top
77	* three bits are actual packet type. For backward compatibility
78	* and in the interest of conserving bits, numbers are chosen so the
79	* IP protocol version number (4) which normally appears in this nibble
80	* means "IP packet".
81	*/
82
83
84	#include <linux/ip.h>
85	#include <linux/tcp.h>
86
87	/* SLIP compression masks for len/vers byte */
88	#define SL_TYPE_IP 0x40
89	#define SL_TYPE_UNCOMPRESSED_TCP 0x70
90	#define SL_TYPE_COMPRESSED_TCP 0x80
91	#define SL_TYPE_ERROR 0x00
92
93	/* Bits in first octet of compressed packet */
94	#define NEW_C 0x40 /* flag bits for what changed in a packet */
95	#define NEW_I 0x20
96	#define NEW_S 0x08
97	#define NEW_A 0x04
98	#define NEW_W 0x02
99	#define NEW_U 0x01
100
101	/* reserved, special-case values of above */
102	#define SPECIAL_I (NEW_S\|NEW_W\|NEW_U) /* echoed interactive traffic */
103	#define SPECIAL_D (NEW_S\|NEW_A\|NEW_W\|NEW_U) /* unidirectional data */
104	#define SPECIALS_MASK (NEW_S\|NEW_A\|NEW_W\|NEW_U)
105
106	#define TCP_PUSH_BIT 0x10
107
108	/*
109	* data type and sizes conversion assumptions:
110	*
111	* VJ code KA9Q style generic
112	* u_char byte_t unsigned char 8 bits
113	* u_short int16 unsigned short 16 bits
114	* u_int int16 unsigned short 16 bits
115	* u_long unsigned long unsigned long 32 bits
116	* int int32 long 32 bits
117	*/
118
119	typedef __u8 byte_t;
120	typedef __u32 int32;
121
122	/*
123	* "state" data for each active tcp conversation on the wire. This is
124	* basically a copy of the entire IP/TCP header from the last packet
125	* we saw from the conversation together with a small identifier
126	* the transmit & receive ends of the line use to locate saved header.
127	*/
128	struct cstate {
129	byte_t cs_this; /* connection id number (xmit) */
130	struct cstate next; / next in ring (xmit) */
131	struct iphdr cs_ip; /* ip/tcp hdr from most recent packet */
132	struct tcphdr cs_tcp;
133	unsigned char cs_ipopt[64];
134	unsigned char cs_tcpopt[64];
135	int cs_hsize;
136	};
137	#define NULLSLSTATE (struct cstate *)0
138
139	/*
140	* all the state data for one serial line (we need one of these per line).
141	*/
142	struct slcompress {
143	struct cstate tstate; / transmit connection states (array)*/
144	struct cstate rstate; / receive connection states (array)*/
145
146	byte_t tslot_limit; /* highest transmit slot id (0-l)*/
147	byte_t rslot_limit; /* highest receive slot id (0-l)*/
148
149	byte_t xmit_oldest; /* oldest xmit in ring */
150	byte_t xmit_current; /* most recent xmit id */
151	byte_t recv_current; /* most recent rcvd id */
152
153	byte_t flags;
154	#define SLF_TOSS 0x01 /* tossing rcvd frames until id received */
155
156	int32 sls_o_nontcp; /* outbound non-TCP packets */
157	int32 sls_o_tcp; /* outbound TCP packets */
158	int32 sls_o_uncompressed; /* outbound uncompressed packets */
159	int32 sls_o_compressed; /* outbound compressed packets */
160	int32 sls_o_searches; /* searches for connection state */
161	int32 sls_o_misses; /* times couldn't find conn. state */
162
163	int32 sls_i_uncompressed; /* inbound uncompressed packets */
164	int32 sls_i_compressed; /* inbound compressed packets */
165	int32 sls_i_error; /* inbound error packets */
166	int32 sls_i_tossed; /* inbound packets tossed because of error */
167
168	int32 sls_i_runt;
169	int32 sls_i_badcheck;
170	};
171	#define NULLSLCOMPR (struct slcompress *)0
172
1da177e4	173	/* In slhc.c: */
b8259d9a AD	174	struct slcompress *slhc_init(int rslots, int tslots);
	175	void slhc_free(struct slcompress *comp);
	176
	177	int slhc_compress(struct slcompress comp, unsigned char icp, int isize,
	178	unsigned char ocp, unsigned char *cpp, int compress_cid);
	179	int slhc_uncompress(struct slcompress comp, unsigned char icp, int isize);
	180	int slhc_remember(struct slcompress comp, unsigned char icp, int isize);
	181	int slhc_toss(struct slcompress *comp);
1da177e4 LT	182
1da177e4 LT	183	#endif /* _SLHC_H */