OSCL-LXR linux-6.0.1/​include/​net/​slhc_vj.h	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 #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".
  */
 
 
 #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) */
     bool    initialized;    /* true if initialized */
     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 */

This page was automatically generated by the 2.1.0 LXR engine. The LXR team