/* * Update: The Berkeley copyright was changed, and the change * is retroactive to all "true" BSD software (ie everything * from UCB as opposed to other peoples code that just carried * the same license). The new copyright doesn't clash with the * GPL, so the module-only restriction has been removed.. */ /* Because this code is derived from the 4.3BSD compress source: * * Copyright (c) 1985, 1986 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * James A. Woods, derived from original work by Spencer Thomas * and Joseph Orost. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * This version is for use with contiguous buffers on Linux-derived systems. * * ==FILEVERSION 20000226== * * NOTE TO MAINTAINERS: * If you modify this file at all, please set the number above to the * date of the modification as YYMMDD (year month day). * bsd_comp.c is shipped with a PPP distribution as well as with * the kernel; if everyone increases the FILEVERSION number above, * then scripts can do the right thing when deciding whether to * install a new bsd_comp.c file. Don't change the format of that * line otherwise, so the installation script can recognize it. * * From: bsd_comp.c,v 1.3 1994/12/08 01:59:58 paulus Exp */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/string.h> #include <linux/ppp_defs.h> #undef PACKETPTR #define PACKETPTR 1 #include <linux/ppp-comp.h> #undef PACKETPTR #include <asm/byteorder.h> /* * PPP "BSD compress" compression * The differences between this compression and the classic BSD LZW * source are obvious from the requirement that the classic code worked * with files while this handles arbitrarily long streams that * are broken into packets. They are: * * When the code size expands, a block of junk is not emitted by * the compressor and not expected by the decompressor. * * New codes are not necessarily assigned every time an old * code is output by the compressor. This is because a packet * end forces a code to be emitted, but does not imply that a * new sequence has been seen. * * The compression ratio is checked at the first end of a packet * after the appropriate gap. Besides simplifying and speeding * things up, this makes it more likely that the transmitter * and receiver will agree when the dictionary is cleared when * compression is not going well. */ /* * Macros to extract protocol version and number of bits * from the third byte of the BSD Compress CCP configuration option. */ #define BSD_VERSION(x) ((x) >> 5) #define BSD_NBITS(x) ((x) & 0x1F) #define BSD_CURRENT_VERSION 1 /* * A dictionary for doing BSD compress. */ struct bsd_dict { union { /* hash value */ <------>unsigned long fcode; <------>struct { #if defined(__LITTLE_ENDIAN) /* Little endian order */ <------> unsigned short prefix; /* preceding code */ <------> unsigned char suffix; /* last character of new code */ <------> unsigned char pad; #elif defined(__BIG_ENDIAN) /* Big endian order */ <------> unsigned char pad; <------> unsigned char suffix; /* last character of new code */ <------> unsigned short prefix; /* preceding code */ #else #error Endianness not defined... #endif <------>} hs; } f; unsigned short codem1; /* output of hash table -1 */ unsigned short cptr; /* map code to hash table entry */ }; struct bsd_db { int totlen; /* length of this structure */ unsigned int hsize; /* size of the hash table */ unsigned char hshift; /* used in hash function */ unsigned char n_bits; /* current bits/code */ unsigned char maxbits; /* maximum bits/code */ unsigned char debug; /* non-zero if debug desired */ unsigned char unit; /* ppp unit number */ unsigned short seqno; /* sequence # of next packet */ unsigned int mru; /* size of receive (decompress) bufr */ unsigned int maxmaxcode; /* largest valid code */ unsigned int max_ent; /* largest code in use */ unsigned int in_count; /* uncompressed bytes, aged */ unsigned int bytes_out; /* compressed bytes, aged */ unsigned int ratio; /* recent compression ratio */ unsigned int checkpoint; /* when to next check the ratio */ unsigned int clear_count; /* times dictionary cleared */ unsigned int incomp_count; /* incompressible packets */ unsigned int incomp_bytes; /* incompressible bytes */ unsigned int uncomp_count; /* uncompressed packets */ unsigned int uncomp_bytes; /* uncompressed bytes */ unsigned int comp_count; /* compressed packets */ unsigned int comp_bytes; /* compressed bytes */ unsigned short *lens; /* array of lengths of codes */ struct bsd_dict *dict; /* dictionary */ }; #define BSD_OVHD 2 /* BSD compress overhead/packet */ #define MIN_BSD_BITS 9 #define BSD_INIT_BITS MIN_BSD_BITS #define MAX_BSD_BITS 15 static void bsd_free (void *state); static void *bsd_alloc(unsigned char *options, int opt_len, int decomp); static void *bsd_comp_alloc (unsigned char *options, int opt_len); static void *bsd_decomp_alloc (unsigned char *options, int opt_len); static int bsd_init (void *db, unsigned char *options, <------><------><------> int opt_len, int unit, int debug, int decomp); static int bsd_comp_init (void *state, unsigned char *options, <------><------><------> int opt_len, int unit, int opthdr, int debug); static int bsd_decomp_init (void *state, unsigned char *options, <------><------><------><------> int opt_len, int unit, int opthdr, int mru, <------><------><------><------> int debug); static void bsd_reset (void *state); static void bsd_comp_stats (void *state, struct compstat *stats); static int bsd_compress (void *state, unsigned char *rptr, <------><------><------> unsigned char *obuf, int isize, int osize); static void bsd_incomp (void *state, unsigned char *ibuf, int icnt); static int bsd_decompress (void *state, unsigned char *ibuf, int isize, <------><------><------><------>unsigned char *obuf, int osize); /* These are in ppp_generic.c */ extern int ppp_register_compressor (struct compressor *cp); extern void ppp_unregister_compressor (struct compressor *cp); /* * the next two codes should not be changed lightly, as they must not * lie within the contiguous general code space. */ #define CLEAR 256 /* table clear output code */ #define FIRST 257 /* first free entry */ #define LAST 255 #define MAXCODE(b) ((1 << (b)) - 1) #define BADCODEM1 MAXCODE(MAX_BSD_BITS) #define BSD_HASH(prefix,suffix,hshift) ((((unsigned long)(suffix))<<(hshift)) \ <------><------><------><------><------> ^ (unsigned long)(prefix)) #define BSD_KEY(prefix,suffix) ((((unsigned long)(suffix)) << 16) \ <------><------><------><------><------> + (unsigned long)(prefix)) #define CHECK_GAP 10000 /* Ratio check interval */ #define RATIO_SCALE_LOG 8 #define RATIO_SCALE (1<<RATIO_SCALE_LOG) #define RATIO_MAX (0x7fffffff>>RATIO_SCALE_LOG) /* * clear the dictionary */ static void bsd_clear(struct bsd_db *db) { db->clear_count++; db->max_ent = FIRST-1; db->n_bits = BSD_INIT_BITS; db->bytes_out = 0; db->in_count = 0; db->ratio = 0; db->checkpoint = CHECK_GAP; } /* * If the dictionary is full, then see if it is time to reset it. * * Compute the compression ratio using fixed-point arithmetic * with 8 fractional bits. * * Since we have an infinite stream instead of a single file, * watch only the local compression ratio. * * Since both peers must reset the dictionary at the same time even in * the absence of CLEAR codes (while packets are incompressible), they * must compute the same ratio. */ static int bsd_check (struct bsd_db *db) /* 1=output CLEAR */ { unsigned int new_ratio; if (db->in_count >= db->checkpoint) { <------>/* age the ratio by limiting the size of the counts */ <------>if (db->in_count >= RATIO_MAX || db->bytes_out >= RATIO_MAX) <------> { <------> db->in_count -= (db->in_count >> 2); <------> db->bytes_out -= (db->bytes_out >> 2); <------> } <------>db->checkpoint = db->in_count + CHECK_GAP; <------>if (db->max_ent >= db->maxmaxcode) <------> { <------> /* Reset the dictionary only if the ratio is worse, <------> * or if it looks as if it has been poisoned <------> * by incompressible data. <------> * <------> * This does not overflow, because <------> * db->in_count <= RATIO_MAX. <------> */ <------> new_ratio = db->in_count << RATIO_SCALE_LOG; <------> if (db->bytes_out != 0) <------> { <------><------>new_ratio /= db->bytes_out; <------> } <------> if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE) <------> { <------><------>bsd_clear (db); <------><------>return 1; <------> } <------> db->ratio = new_ratio; <------> } } return 0; } /* * Return statistics. */ static void bsd_comp_stats (void *state, struct compstat *stats) { struct bsd_db *db = (struct bsd_db *) state; stats->unc_bytes = db->uncomp_bytes; stats->unc_packets = db->uncomp_count; stats->comp_bytes = db->comp_bytes; stats->comp_packets = db->comp_count; stats->inc_bytes = db->incomp_bytes; stats->inc_packets = db->incomp_count; stats->in_count = db->in_count; stats->bytes_out = db->bytes_out; } /* * Reset state, as on a CCP ResetReq. */ static void bsd_reset (void *state) { struct bsd_db *db = (struct bsd_db *) state; bsd_clear(db); db->seqno = 0; db->clear_count = 0; } /* * Release the compression structure */ static void bsd_free (void *state) { <------>struct bsd_db *db = state; <------>if (!db) <------><------>return; /* * Release the dictionary */ <------>vfree(db->dict); <------>db->dict = NULL; /* * Release the string buffer */ <------>vfree(db->lens); <------>db->lens = NULL; /* * Finally release the structure itself. */ <------>kfree(db); } /* * Allocate space for a (de) compressor. */ static void *bsd_alloc (unsigned char *options, int opt_len, int decomp) { int bits; unsigned int hsize, hshift, maxmaxcode; struct bsd_db *db; if (opt_len != 3 || options[0] != CI_BSD_COMPRESS || options[1] != 3 <------>|| BSD_VERSION(options[2]) != BSD_CURRENT_VERSION) { <------>return NULL; } bits = BSD_NBITS(options[2]); switch (bits) { case 9: /* needs 82152 for both directions */ case 10: /* needs 84144 */ case 11: /* needs 88240 */ case 12: /* needs 96432 */ <------>hsize = 5003; <------>hshift = 4; <------>break; case 13: /* needs 176784 */ <------>hsize = 9001; <------>hshift = 5; <------>break; case 14: /* needs 353744 */ <------>hsize = 18013; <------>hshift = 6; <------>break; case 15: /* needs 691440 */ <------>hsize = 35023; <------>hshift = 7; <------>break; case 16: /* needs 1366160--far too much, */ <------>/* hsize = 69001; */ /* and 69001 is too big for cptr */ <------>/* hshift = 8; */ /* in struct bsd_db */ <------>/* break; */ default: <------>return NULL; } /* * Allocate the main control structure for this instance. */ maxmaxcode = MAXCODE(bits); db = kzalloc(sizeof (struct bsd_db), <------><------><------><------><------> GFP_KERNEL); if (!db) { <------>return NULL; } /* * Allocate space for the dictionary. This may be more than one page in * length. */ db->dict = vmalloc(array_size(hsize, sizeof(struct bsd_dict))); if (!db->dict) { <------>bsd_free (db); <------>return NULL; } /* * If this is the compression buffer then there is no length data. */ if (!decomp) { <------>db->lens = NULL; } /* * For decompression, the length information is needed as well. */ else { db->lens = vmalloc(array_size(sizeof(db->lens[0]), (maxmaxcode + 1))); <------>if (!db->lens) <------> { <------> bsd_free (db); <------> return NULL; <------> } } /* * Initialize the data information for the compression code */ db->totlen = sizeof (struct bsd_db) + (sizeof (struct bsd_dict) * hsize); db->hsize = hsize; db->hshift = hshift; db->maxmaxcode = maxmaxcode; db->maxbits = bits; return (void *) db; } static void *bsd_comp_alloc (unsigned char *options, int opt_len) { return bsd_alloc (options, opt_len, 0); } static void *bsd_decomp_alloc (unsigned char *options, int opt_len) { return bsd_alloc (options, opt_len, 1); } /* * Initialize the database. */ static int bsd_init (void *state, unsigned char *options, <------><------> int opt_len, int unit, int debug, int decomp) { struct bsd_db *db = state; int indx; if ((opt_len != 3) || (options[0] != CI_BSD_COMPRESS) || (options[1] != 3) <------>|| (BSD_VERSION(options[2]) != BSD_CURRENT_VERSION) <------>|| (BSD_NBITS(options[2]) != db->maxbits) <------>|| (decomp && db->lens == NULL)) { <------>return 0; } if (decomp) { <------>indx = LAST; <------>do <------> { <------> db->lens[indx] = 1; <------> } <------>while (indx-- > 0); } indx = db->hsize; while (indx-- != 0) { <------>db->dict[indx].codem1 = BADCODEM1; <------>db->dict[indx].cptr = 0; } db->unit = unit; db->mru = 0; #ifndef DEBUG if (debug) #endif db->debug = 1; bsd_reset(db); return 1; } static int bsd_comp_init (void *state, unsigned char *options, <------><------><------> int opt_len, int unit, int opthdr, int debug) { return bsd_init (state, options, opt_len, unit, debug, 0); } static int bsd_decomp_init (void *state, unsigned char *options, <------><------><------> int opt_len, int unit, int opthdr, int mru, <------><------><------> int debug) { return bsd_init (state, options, opt_len, unit, debug, 1); } /* * Obtain pointers to the various structures in the compression tables */ #define dict_ptrx(p,idx) &(p->dict[idx]) #define lens_ptrx(p,idx) &(p->lens[idx]) #ifdef DEBUG static unsigned short *lens_ptr(struct bsd_db *db, int idx) { if ((unsigned int) idx > (unsigned int) db->maxmaxcode) { <------>printk ("<9>ppp: lens_ptr(%d) > max\n", idx); <------>idx = 0; } return lens_ptrx (db, idx); } static struct bsd_dict *dict_ptr(struct bsd_db *db, int idx) { if ((unsigned int) idx >= (unsigned int) db->hsize) { <------>printk ("<9>ppp: dict_ptr(%d) > max\n", idx); <------>idx = 0; } return dict_ptrx (db, idx); } #else #define lens_ptr(db,idx) lens_ptrx(db,idx) #define dict_ptr(db,idx) dict_ptrx(db,idx) #endif /* * compress a packet * * The result of this function is the size of the compressed * packet. A zero is returned if the packet was not compressed * for some reason, such as the size being larger than uncompressed. * * One change from the BSD compress command is that when the * code size expands, we do not output a bunch of padding. */ static int bsd_compress (void *state, unsigned char *rptr, unsigned char *obuf, <------><------><------> int isize, int osize) { struct bsd_db *db; int hshift; unsigned int max_ent; unsigned int n_bits; unsigned int bitno; unsigned long accm; int ent; unsigned long fcode; struct bsd_dict *dictp; unsigned char c; int hval; int disp; int ilen; int mxcode; unsigned char *wptr; int olen; #define PUTBYTE(v) \ { \ ++olen; \ if (wptr) \ { \ <------>*wptr++ = (unsigned char) (v); \ <------>if (olen >= osize) \ <------> { \ <------> wptr = NULL; \ <------> } \ } \ } #define OUTPUT(ent) \ { \ bitno -= n_bits; \ accm |= ((ent) << bitno); \ do \ { \ <------>PUTBYTE(accm >> 24); \ <------>accm <<= 8; \ <------>bitno += 8; \ } \ while (bitno <= 24); \ } /* * If the protocol is not in the range we're interested in, * just return without compressing the packet. If it is, * the protocol becomes the first byte to compress. */ ent = PPP_PROTOCOL(rptr); if (ent < 0x21 || ent > 0xf9) { <------>return 0; } db = (struct bsd_db *) state; hshift = db->hshift; max_ent = db->max_ent; n_bits = db->n_bits; bitno = 32; accm = 0; mxcode = MAXCODE (n_bits); /* Initialize the output pointers */ wptr = obuf; olen = PPP_HDRLEN + BSD_OVHD; if (osize > isize) { <------>osize = isize; } /* This is the PPP header information */ if (wptr) { <------>*wptr++ = PPP_ADDRESS(rptr); <------>*wptr++ = PPP_CONTROL(rptr); <------>*wptr++ = 0; <------>*wptr++ = PPP_COMP; <------>*wptr++ = db->seqno >> 8; <------>*wptr++ = db->seqno; } /* Skip the input header */ rptr += PPP_HDRLEN; isize -= PPP_HDRLEN; ilen = ++isize; /* Low byte of protocol is counted as input */ while (--ilen > 0) { <------>c = *rptr++; <------>fcode = BSD_KEY (ent, c); <------>hval = BSD_HASH (ent, c, hshift); <------>dictp = dict_ptr (db, hval); <------>/* Validate and then check the entry. */ <------>if (dictp->codem1 >= max_ent) <------> { <------> goto nomatch; <------> } <------>if (dictp->f.fcode == fcode) <------> { <------> ent = dictp->codem1 + 1; <------> continue; /* found (prefix,suffix) */ <------> } <------>/* continue probing until a match or invalid entry */ <------>disp = (hval == 0) ? 1 : hval; <------>do <------> { <------> hval += disp; <------> if (hval >= db->hsize) <------> { <------><------>hval -= db->hsize; <------> } <------> dictp = dict_ptr (db, hval); <------> if (dictp->codem1 >= max_ent) <------> { <------><------>goto nomatch; <------> } <------> } <------>while (dictp->f.fcode != fcode); <------>ent = dictp->codem1 + 1; /* finally found (prefix,suffix) */ <------>continue; nomatch: <------>OUTPUT(ent); /* output the prefix */ <------>/* code -> hashtable */ <------>if (max_ent < db->maxmaxcode) <------> { <------> struct bsd_dict *dictp2; <------> struct bsd_dict *dictp3; <------> int indx; <------> /* expand code size if needed */ <------> if (max_ent >= mxcode) <------> { <------><------>db->n_bits = ++n_bits; <------><------>mxcode = MAXCODE (n_bits); <------> } <------> /* Invalidate old hash table entry using <------> * this code, and then take it over. <------> */ <------> dictp2 = dict_ptr (db, max_ent + 1); <------> indx = dictp2->cptr; <------> dictp3 = dict_ptr (db, indx); <------> if (dictp3->codem1 == max_ent) <------> { <------><------>dictp3->codem1 = BADCODEM1; <------> } <------> dictp2->cptr = hval; <------> dictp->codem1 = max_ent; <------> dictp->f.fcode = fcode; <------> db->max_ent = ++max_ent; <------> if (db->lens) <------> { <------><------>unsigned short *len1 = lens_ptr (db, max_ent); <------><------>unsigned short *len2 = lens_ptr (db, ent); <------><------>*len1 = *len2 + 1; <------> } <------> } <------>ent = c; } OUTPUT(ent); /* output the last code */ db->bytes_out += olen - PPP_HDRLEN - BSD_OVHD; db->uncomp_bytes += isize; db->in_count += isize; ++db->uncomp_count; ++db->seqno; if (bitno < 32) { <------>++db->bytes_out; /* must be set before calling bsd_check */ } /* * Generate the clear command if needed */ if (bsd_check(db)) { <------>OUTPUT (CLEAR); } /* * Pad dribble bits of last code with ones. * Do not emit a completely useless byte of ones. */ if (bitno != 32) { <------>PUTBYTE((accm | (0xff << (bitno-8))) >> 24); } /* * Increase code size if we would have without the packet * boundary because the decompressor will do so. */ if (max_ent >= mxcode && max_ent < db->maxmaxcode) { <------>db->n_bits++; } /* If output length is too large then this is an incomplete frame. */ if (wptr == NULL) { <------>++db->incomp_count; <------>db->incomp_bytes += isize; <------>olen = 0; } else /* Count the number of compressed frames */ { <------>++db->comp_count; <------>db->comp_bytes += olen; } /* Return the resulting output length */ return olen; #undef OUTPUT #undef PUTBYTE } /* * Update the "BSD Compress" dictionary on the receiver for * incompressible data by pretending to compress the incoming data. */ static void bsd_incomp (void *state, unsigned char *ibuf, int icnt) { (void) bsd_compress (state, ibuf, (char *) 0, icnt, 0); } /* * Decompress "BSD Compress". * * Because of patent problems, we return DECOMP_ERROR for errors * found by inspecting the input data and for system problems, but * DECOMP_FATALERROR for any errors which could possibly be said to * be being detected "after" decompression. For DECOMP_ERROR, * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be * infringing a patent of Motorola's if we do, so we take CCP down * instead. * * Given that the frame has the correct sequence number and a good FCS, * errors such as invalid codes in the input most likely indicate a * bug, so we return DECOMP_FATALERROR for them in order to turn off * compression, even though they are detected by inspecting the input. */ static int bsd_decompress (void *state, unsigned char *ibuf, int isize, <------><------><------> unsigned char *obuf, int osize) { struct bsd_db *db; unsigned int max_ent; unsigned long accm; unsigned int bitno; /* 1st valid bit in accm */ unsigned int n_bits; unsigned int tgtbitno; /* bitno when we have a code */ struct bsd_dict *dictp; int explen; int seq; unsigned int incode; unsigned int oldcode; unsigned int finchar; unsigned char *p; unsigned char *wptr; int adrs; int ctrl; int ilen; int codelen; int extra; db = (struct bsd_db *) state; max_ent = db->max_ent; accm = 0; bitno = 32; /* 1st valid bit in accm */ n_bits = db->n_bits; tgtbitno = 32 - n_bits; /* bitno when we have a code */ /* * Save the address/control from the PPP header * and then get the sequence number. */ adrs = PPP_ADDRESS (ibuf); ctrl = PPP_CONTROL (ibuf); seq = (ibuf[4] << 8) + ibuf[5]; ibuf += (PPP_HDRLEN + 2); ilen = isize - (PPP_HDRLEN + 2); /* * Check the sequence number and give up if it differs from * the value we're expecting. */ if (seq != db->seqno) { <------>if (db->debug) <------> { <------> printk("bsd_decomp%d: bad sequence # %d, expected %d\n", <------><------> db->unit, seq, db->seqno - 1); <------> } <------>return DECOMP_ERROR; } ++db->seqno; db->bytes_out += ilen; /* * Fill in the ppp header, but not the last byte of the protocol * (that comes from the decompressed data). */ wptr = obuf; *wptr++ = adrs; *wptr++ = ctrl; *wptr++ = 0; oldcode = CLEAR; explen = 3; /* * Keep the checkpoint correctly so that incompressible packets * clear the dictionary at the proper times. */ for (;;) { <------>if (ilen-- <= 0) <------> { <------> db->in_count += (explen - 3); /* don't count the header */ <------> break; <------> } <------>/* <------> * Accumulate bytes until we have a complete code. <------> * Then get the next code, relying on the 32-bit, <------> * unsigned accm to mask the result. <------> */ <------>bitno -= 8; <------>accm |= *ibuf++ << bitno; <------>if (tgtbitno < bitno) <------> { <------> continue; <------> } <------>incode = accm >> tgtbitno; <------>accm <<= n_bits; <------>bitno += n_bits; <------>/* <------> * The dictionary must only be cleared at the end of a packet. <------> */ <------>if (incode == CLEAR) <------> { <------> if (ilen > 0) <------> { <------><------>if (db->debug) <------><------> { <------><------> printk("bsd_decomp%d: bad CLEAR\n", db->unit); <------><------> } <------><------>return DECOMP_FATALERROR; /* probably a bug */ <------> } <------> bsd_clear(db); <------> break; <------> } <------>if ((incode > max_ent + 2) || (incode > db->maxmaxcode) <------> || (incode > max_ent && oldcode == CLEAR)) <------> { <------> if (db->debug) <------> { <------><------>printk("bsd_decomp%d: bad code 0x%x oldcode=0x%x ", <------><------> db->unit, incode, oldcode); <------><------>printk("max_ent=0x%x explen=%d seqno=%d\n", <------><------> max_ent, explen, db->seqno); <------> } <------> return DECOMP_FATALERROR; /* probably a bug */ <------> } <------>/* Special case for KwKwK string. */ <------>if (incode > max_ent) <------> { <------> finchar = oldcode; <------> extra = 1; <------> } <------>else <------> { <------> finchar = incode; <------> extra = 0; <------> } <------>codelen = *(lens_ptr (db, finchar)); <------>explen += codelen + extra; <------>if (explen > osize) <------> { <------> if (db->debug) <------> { <------><------>printk("bsd_decomp%d: ran out of mru\n", db->unit); #ifdef DEBUG <------><------>printk(" len=%d, finchar=0x%x, codelen=%d, explen=%d\n", <------><------> ilen, finchar, codelen, explen); #endif <------> } <------> return DECOMP_FATALERROR; <------> } <------>/* <------> * Decode this code and install it in the decompressed buffer. <------> */ <------>wptr += codelen; <------>p = wptr; <------>while (finchar > LAST) <------> { <------> struct bsd_dict *dictp2 = dict_ptr (db, finchar); <------> dictp = dict_ptr (db, dictp2->cptr); #ifdef DEBUG <------> if (--codelen <= 0 || dictp->codem1 != finchar-1) <------> { <------><------>if (codelen <= 0) <------><------> { <------><------> printk("bsd_decomp%d: fell off end of chain ", db->unit); <------><------> printk("0x%x at 0x%x by 0x%x, max_ent=0x%x\n", <------><------><------> incode, finchar, dictp2->cptr, max_ent); <------><------> } <------><------>else <------><------> { <------><------> if (dictp->codem1 != finchar-1) <------><------> { <------><------><------>printk("bsd_decomp%d: bad code chain 0x%x " <------><------><------> "finchar=0x%x ", <------><------><------> db->unit, incode, finchar); <------><------><------>printk("oldcode=0x%x cptr=0x%x codem1=0x%x\n", <------><------><------> oldcode, dictp2->cptr, dictp->codem1); <------><------> } <------><------> } <------><------>return DECOMP_FATALERROR; <------> } #endif <------> *--p = dictp->f.hs.suffix; <------> finchar = dictp->f.hs.prefix; <------> } <------>*--p = finchar; #ifdef DEBUG <------>if (--codelen != 0) <------> { <------> printk("bsd_decomp%d: short by %d after code 0x%x, max_ent=0x%x\n", <------><------> db->unit, codelen, incode, max_ent); <------> } #endif <------>if (extra) /* the KwKwK case again */ <------> { <------> *wptr++ = finchar; <------> } <------>/* <------> * If not first code in a packet, and <------> * if not out of code space, then allocate a new code. <------> * <------> * Keep the hash table correct so it can be used <------> * with uncompressed packets. <------> */ <------>if (oldcode != CLEAR && max_ent < db->maxmaxcode) <------> { <------> struct bsd_dict *dictp2, *dictp3; <------> unsigned short *lens1, *lens2; <------> unsigned long fcode; <------> int hval, disp, indx; <------> fcode = BSD_KEY(oldcode,finchar); <------> hval = BSD_HASH(oldcode,finchar,db->hshift); <------> dictp = dict_ptr (db, hval); <------> /* look for a free hash table entry */ <------> if (dictp->codem1 < max_ent) <------> { <------><------>disp = (hval == 0) ? 1 : hval; <------><------>do <------><------> { <------><------> hval += disp; <------><------> if (hval >= db->hsize) <------><------> { <------><------><------>hval -= db->hsize; <------><------> } <------><------> dictp = dict_ptr (db, hval); <------><------> } <------><------>while (dictp->codem1 < max_ent); <------> } <------> /* <------> * Invalidate previous hash table entry <------> * assigned this code, and then take it over <------> */ <------> dictp2 = dict_ptr (db, max_ent + 1); <------> indx = dictp2->cptr; <------> dictp3 = dict_ptr (db, indx); <------> if (dictp3->codem1 == max_ent) <------> { <------><------>dictp3->codem1 = BADCODEM1; <------> } <------> dictp2->cptr = hval; <------> dictp->codem1 = max_ent; <------> dictp->f.fcode = fcode; <------> db->max_ent = ++max_ent; <------> /* Update the length of this string. */ <------> lens1 = lens_ptr (db, max_ent); <------> lens2 = lens_ptr (db, oldcode); <------> *lens1 = *lens2 + 1; <------> /* Expand code size if needed. */ <------> if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) <------> { <------><------>db->n_bits = ++n_bits; <------><------>tgtbitno = 32-n_bits; <------> } <------> } <------>oldcode = incode; } ++db->comp_count; ++db->uncomp_count; db->comp_bytes += isize - BSD_OVHD - PPP_HDRLEN; db->uncomp_bytes += explen; if (bsd_check(db)) { <------>if (db->debug) <------> { <------> printk("bsd_decomp%d: peer should have cleared dictionary on %d\n", <------><------> db->unit, db->seqno - 1); <------> } } return explen; } /************************************************************* * Table of addresses for the BSD compression module *************************************************************/ static struct compressor ppp_bsd_compress = { <------>.compress_proto = CI_BSD_COMPRESS, <------>.comp_alloc = bsd_comp_alloc, <------>.comp_free = bsd_free, <------>.comp_init = bsd_comp_init, <------>.comp_reset = bsd_reset, <------>.compress = bsd_compress, <------>.comp_stat = bsd_comp_stats, <------>.decomp_alloc = bsd_decomp_alloc, <------>.decomp_free = bsd_free, <------>.decomp_init = bsd_decomp_init, <------>.decomp_reset = bsd_reset, <------>.decompress = bsd_decompress, <------>.incomp = bsd_incomp, <------>.decomp_stat = bsd_comp_stats, <------>.owner = THIS_MODULE }; /************************************************************* * Module support routines *************************************************************/ static int __init bsdcomp_init(void) { <------>int answer = ppp_register_compressor(&ppp_bsd_compress); <------>if (answer == 0) <------><------>printk(KERN_INFO "PPP BSD Compression module registered\n"); <------>return answer; } static void __exit bsdcomp_cleanup(void) { <------>ppp_unregister_compressor(&ppp_bsd_compress); } module_init(bsdcomp_init); module_exit(bsdcomp_cleanup); MODULE_LICENSE("Dual BSD/GPL"); MODULE_ALIAS("ppp-compress-" __stringify(CI_BSD_COMPRESS));
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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