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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [include/] [net/] [slhc_vj.h] - Blame information for rev 1777

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1 1633 jcastillo
#ifndef _SLHC_H
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#define _SLHC_H
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/*
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 * Definitions for tcp compression routines.
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 *
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 * $Header: /home/marcus/revision_ctrl_test/oc_cvs/cvs/or1k/rc203soc/sw/uClinux/include/net/slhc_vj.h,v 1.1 2005-12-20 11:33:02 jcastillo Exp $
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 *
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 * Copyright (c) 1989 Regents of the University of California.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms are permitted
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 * provided that the above copyright notice and this paragraph are
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 * duplicated in all such forms and that any documentation,
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 * advertising materials, and other materials related to such
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 * distribution and use acknowledge that the software was developed
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 * by the University of California, Berkeley.  The name of the
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 * University may not be used to endorse or promote products derived
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 * from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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 *
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 *      Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
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 *      - Initial distribution.
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 *
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 *
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 * modified for KA9Q Internet Software Package by
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 * Katie Stevens (dkstevens@ucdavis.edu)
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 * University of California, Davis
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 * Computing Services
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 *      - 01-31-90      initial adaptation
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 *
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 *      - Feb 1991      Bill_Simpson@um.cc.umich.edu
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 *                      variable number of conversation slots
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 *                      allow zero or one slots
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 *                      separate routines
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 *                      status display
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 */
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/*
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 * Compressed packet format:
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 *
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 * The first octet contains the packet type (top 3 bits), TCP
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 * 'push' bit, and flags that indicate which of the 4 TCP sequence
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 * numbers have changed (bottom 5 bits).  The next octet is a
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 * conversation number that associates a saved IP/TCP header with
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 * the compressed packet.  The next two octets are the TCP checksum
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 * from the original datagram.  The next 0 to 15 octets are
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 * sequence number changes, one change per bit set in the header
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 * (there may be no changes and there are two special cases where
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 * the receiver implicitly knows what changed -- see below).
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 *
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 * There are 5 numbers which can change (they are always inserted
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 * in the following order): TCP urgent pointer, window,
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 * acknowledgment, sequence number and IP ID.  (The urgent pointer
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 * is different from the others in that its value is sent, not the
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 * change in value.)  Since typical use of SLIP links is biased
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 * toward small packets (see comments on MTU/MSS below), changes
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 * use a variable length coding with one octet for numbers in the
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 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
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 * range 256 - 65535 or 0.  (If the change in sequence number or
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 * ack is more than 65535, an uncompressed packet is sent.)
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 */
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/*
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 * Packet types (must not conflict with IP protocol version)
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 *
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 * The top nibble of the first octet is the packet type.  There are
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 * three possible types: IP (not proto TCP or tcp with one of the
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 * control flags set); uncompressed TCP (a normal IP/TCP packet but
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 * with the 8-bit protocol field replaced by an 8-bit connection id --
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 * this type of packet syncs the sender & receiver); and compressed
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 * TCP (described above).
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 *
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 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
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 * is logically part of the 4-bit "changes" field that follows.  Top
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 * three bits are actual packet type.  For backward compatibility
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 * and in the interest of conserving bits, numbers are chosen so the
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 * IP protocol version number (4) which normally appears in this nibble
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 * means "IP packet".
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 */
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/* SLIP compression masks for len/vers byte */
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#define SL_TYPE_IP 0x40
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#define SL_TYPE_UNCOMPRESSED_TCP 0x70
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#define SL_TYPE_COMPRESSED_TCP 0x80
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#define SL_TYPE_ERROR 0x00
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/* Bits in first octet of compressed packet */
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#define NEW_C   0x40    /* flag bits for what changed in a packet */
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#define NEW_I   0x20
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#define NEW_S   0x08
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#define NEW_A   0x04
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#define NEW_W   0x02
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#define NEW_U   0x01
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/* reserved, special-case values of above */
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#define SPECIAL_I (NEW_S|NEW_W|NEW_U)           /* echoed interactive traffic */
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#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U)     /* unidirectional data */
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#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
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#define TCP_PUSH_BIT 0x10
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/*
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 * data type and sizes conversion assumptions:
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 *
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 *      VJ code         KA9Q style      generic
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 *      u_char          byte_t          unsigned char    8 bits
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 *      u_short         int16           unsigned short  16 bits
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 *      u_int           int16           unsigned short  16 bits
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 *      u_long          unsigned long   unsigned long   32 bits
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 *      int             int32           long            32 bits
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 */
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typedef unsigned char byte_t;
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typedef unsigned long int32;
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/*
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 * "state" data for each active tcp conversation on the wire.  This is
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 * basically a copy of the entire IP/TCP header from the last packet
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 * we saw from the conversation together with a small identifier
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 * the transmit & receive ends of the line use to locate saved header.
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 */
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struct cstate {
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        byte_t  cs_this;        /* connection id number (xmit) */
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        struct cstate *next;    /* next in ring (xmit) */
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        struct iphdr cs_ip;     /* ip/tcp hdr from most recent packet */
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        struct tcphdr cs_tcp;
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        unsigned char cs_ipopt[64];
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        unsigned char cs_tcpopt[64];
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        int cs_hsize;
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};
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#define NULLSLSTATE     (struct cstate *)0
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/*
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 * all the state data for one serial line (we need one of these per line).
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 */
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struct slcompress {
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        struct cstate *tstate;  /* transmit connection states (array)*/
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        struct cstate *rstate;  /* receive connection states (array)*/
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        byte_t tslot_limit;     /* highest transmit slot id (0-l)*/
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        byte_t rslot_limit;     /* highest receive slot id (0-l)*/
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        byte_t xmit_oldest;     /* oldest xmit in ring */
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        byte_t xmit_current;    /* most recent xmit id */
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        byte_t recv_current;    /* most recent rcvd id */
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        byte_t flags;
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#define SLF_TOSS        0x01    /* tossing rcvd frames until id received */
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        int32 sls_o_nontcp;     /* outbound non-TCP packets */
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        int32 sls_o_tcp;        /* outbound TCP packets */
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        int32 sls_o_uncompressed;       /* outbound uncompressed packets */
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        int32 sls_o_compressed; /* outbound compressed packets */
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        int32 sls_o_searches;   /* searches for connection state */
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        int32 sls_o_misses;     /* times couldn't find conn. state */
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        int32 sls_i_uncompressed;       /* inbound uncompressed packets */
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        int32 sls_i_compressed; /* inbound compressed packets */
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        int32 sls_i_error;      /* inbound error packets */
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        int32 sls_i_tossed;     /* inbound packets tossed because of error */
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        int32 sls_i_runt;
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        int32 sls_i_badcheck;
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};
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#define NULLSLCOMPR     (struct slcompress *)0
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#define __ARGS(x) x
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/* In slhc.c: */
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struct slcompress *slhc_init __ARGS((int rslots, int tslots));
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void slhc_free __ARGS((struct slcompress *comp));
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int slhc_compress __ARGS((struct slcompress *comp, unsigned char *icp,
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                          int isize, unsigned char *ocp, unsigned char **cpp,
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                          int compress_cid));
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int slhc_uncompress __ARGS((struct slcompress *comp, unsigned char *icp,
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                            int isize));
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int slhc_remember __ARGS((struct slcompress *comp, unsigned char *icp,
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                          int isize));
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int slhc_toss __ARGS((struct slcompress *comp));
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void slhc_i_status __ARGS((struct slcompress *comp));
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void slhc_o_status __ARGS((struct slcompress *comp));
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#endif  /* _SLHC_H */

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