patch-1.3.99 linux/include/net/slhc_vj.h

• Lines: 188
• Date: Mon May 6 07:28:54 1996
• Orig file: v1.3.98/linux/include/net/slhc_vj.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.98/linux/include/net/slhc_vj.h linux/include/net/slhc_vj.h
@@ -0,0 +1,187 @@
+#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 (van@helios.ee.lbl.gov), Dec 31, 1989:
+ *	- Initial distribution.
+ *
+ *
+ * modified for KA9Q Internet Software Package by
+ * Katie Stevens (dkstevens@ucdavis.edu)
+ * University of California, Davis
+ * Computing Services
+ *	- 01-31-90	initial adaptation
+ *
+ *	- Feb 1991	Bill_Simpson@um.cc.umich.edu
+ *			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".
+ */
+
+/* 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 unsigned char byte_t;
+typedef unsigned long 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
+
+#define __ARGS(x) x
+
+/* In slhc.c: */
+struct slcompress *slhc_init __ARGS((int rslots, int tslots));
+void slhc_free __ARGS((struct slcompress *comp));
+
+int slhc_compress __ARGS((struct slcompress *comp, unsigned char *icp,
+			  int isize, unsigned char *ocp, unsigned char **cpp,
+			  int compress_cid));
+int slhc_uncompress __ARGS((struct slcompress *comp, unsigned char *icp,
+			    int isize));
+int slhc_remember __ARGS((struct slcompress *comp, unsigned char *icp,
+			  int isize));
+int slhc_toss __ARGS((struct slcompress *comp));
+
+void slhc_i_status __ARGS((struct slcompress *comp));
+void slhc_o_status __ARGS((struct slcompress *comp));
+
+#endif	/* _SLHC_H */