1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * ppp-comp.h - Definitions for doing PPP packet compression. 4 * 5 * Copyright 1994-1998 Paul Mackerras. 6 */ 7 #ifndef _NET_PPP_COMP_H 8 #define _NET_PPP_COMP_H 9 10 #include <uapi/linux/ppp-comp.h> 11 12 13 struct module; 14 15 /* 16 * The following symbols control whether we include code for 17 * various compression methods. 18 */ 19 20 #ifndef DO_BSD_COMPRESS 21 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ 22 #endif 23 #ifndef DO_DEFLATE 24 #define DO_DEFLATE 1 /* by default, include Deflate */ 25 #endif 26 #define DO_PREDICTOR_1 0 27 #define DO_PREDICTOR_2 0 28 29 /* 30 * Structure giving methods for compression/decompression. 31 */ 32 33 struct compressor { 34 int compress_proto; /* CCP compression protocol number */ 35 36 /* Allocate space for a compressor (transmit side) */ 37 void *(*comp_alloc) (unsigned char *options, int opt_len); 38 39 /* Free space used by a compressor */ 40 void (*comp_free) (void *state); 41 42 /* Initialize a compressor */ 43 int (*comp_init) (void *state, unsigned char *options, 44 int opt_len, int unit, int opthdr, int debug); 45 46 /* Reset a compressor */ 47 void (*comp_reset) (void *state); 48 49 /* Compress a packet */ 50 int (*compress) (void *state, unsigned char *rptr, 51 unsigned char *obuf, int isize, int osize); 52 53 /* Return compression statistics */ 54 void (*comp_stat) (void *state, struct compstat *stats); 55 56 /* Allocate space for a decompressor (receive side) */ 57 void *(*decomp_alloc) (unsigned char *options, int opt_len); 58 59 /* Free space used by a decompressor */ 60 void (*decomp_free) (void *state); 61 62 /* Initialize a decompressor */ 63 int (*decomp_init) (void *state, unsigned char *options, 64 int opt_len, int unit, int opthdr, int mru, 65 int debug); 66 67 /* Reset a decompressor */ 68 void (*decomp_reset) (void *state); 69 70 /* Decompress a packet. */ 71 int (*decompress) (void *state, unsigned char *ibuf, int isize, 72 unsigned char *obuf, int osize); 73 74 /* Update state for an incompressible packet received */ 75 void (*incomp) (void *state, unsigned char *ibuf, int icnt); 76 77 /* Return decompression statistics */ 78 void (*decomp_stat) (void *state, struct compstat *stats); 79 80 /* Used in locking compressor modules */ 81 struct module *owner; 82 /* Extra skb space needed by the compressor algorithm */ 83 unsigned int comp_extra; 84 }; 85 86 /* 87 * The return value from decompress routine is the length of the 88 * decompressed packet if successful, otherwise DECOMP_ERROR 89 * or DECOMP_FATALERROR if an error occurred. 90 * 91 * We need to make this distinction so that we can disable certain 92 * useful functionality, namely sending a CCP reset-request as a result 93 * of an error detected after decompression. This is to avoid infringing 94 * a patent held by Motorola. 95 * Don't you just lurve software patents. 96 */ 97 98 #define DECOMP_ERROR -1 /* error detected before decomp. */ 99 #define DECOMP_FATALERROR -2 /* error detected after decomp. */ 100 101 extern int ppp_register_compressor(struct compressor *); 102 extern void ppp_unregister_compressor(struct compressor *); 103 #endif /* _NET_PPP_COMP_H */ 104