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Diffstat (limited to '')
| -rw-r--r-- | c/src/exec/libnetworking/net/bsd-comp.c | 1117 |
1 files changed, 0 insertions, 1117 deletions
diff --git a/c/src/exec/libnetworking/net/bsd-comp.c b/c/src/exec/libnetworking/net/bsd-comp.c deleted file mode 100644 index 294457cc2c..0000000000 --- a/c/src/exec/libnetworking/net/bsd-comp.c +++ /dev/null @@ -1,1117 +0,0 @@ -/* $Id$ */ - -/* 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 mbufs on BSD-derived systems. - */ - -#include <sys/param.h> -#include <sys/types.h> -#include <sys/systm.h> -#include <sys/mbuf.h> -#include <sys/socket.h> -#include <net/if.h> -#include <net/if_types.h> -#include <net/ppp_defs.h> -#include <net/if_ppp.h> - -#define PACKETPTR struct mbuf * -#include <net/ppp-comp.h> - -#if DO_BSD_COMPRESS -/* - * 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. - */ - -/* - * A dictionary for doing BSD compress. - */ -struct bsd_db { - int totlen; /* length of this structure */ - u_int hsize; /* size of the hash table */ - u_char hshift; /* used in hash function */ - u_char n_bits; /* current bits/code */ - u_char maxbits; - u_char debug; - u_char unit; - u_int16_t seqno; /* sequence # of next packet */ - u_int hdrlen; /* header length to preallocate */ - u_int mru; - u_int maxmaxcode; /* largest valid code */ - u_int max_ent; /* largest code in use */ - u_int in_count; /* uncompressed bytes, aged */ - u_int bytes_out; /* compressed bytes, aged */ - u_int ratio; /* recent compression ratio */ - u_int checkpoint; /* when to next check the ratio */ - u_int clear_count; /* times dictionary cleared */ - u_int incomp_count; /* incompressible packets */ - u_int incomp_bytes; /* incompressible bytes */ - u_int uncomp_count; /* uncompressed packets */ - u_int uncomp_bytes; /* uncompressed bytes */ - u_int comp_count; /* compressed packets */ - u_int comp_bytes; /* compressed bytes */ - u_int16_t *lens; /* array of lengths of codes */ - struct bsd_dict { - union { /* hash value */ - u_int32_t fcode; - struct { -#if BYTE_ORDER == LITTLE_ENDIAN - u_int16_t prefix; /* preceding code */ - u_char suffix; /* last character of new code */ - u_char pad; -#else - u_char pad; - u_char suffix; /* last character of new code */ - u_int16_t prefix; /* preceding code */ -#endif - } hs; - } f; - u_int16_t codem1; /* output of hash table -1 */ - u_int16_t cptr; /* map code to hash table entry */ - } dict[1]; -}; - -#define BSD_OVHD 2 /* BSD compress overhead/packet */ -#define BSD_INIT_BITS BSD_MIN_BITS - -static void *bsd_comp_alloc __P((u_char *options, int opt_len)); -static void *bsd_decomp_alloc __P((u_char *options, int opt_len)); -static void bsd_free __P((void *state)); -static int bsd_comp_init __P((void *state, u_char *options, int opt_len, - int unit, int hdrlen, int debug)); -static int bsd_decomp_init __P((void *state, u_char *options, int opt_len, - int unit, int hdrlen, int mru, int debug)); -static int bsd_compress __P((void *state, struct mbuf **mret, - struct mbuf *mp, int slen, int maxolen)); -static void bsd_incomp __P((void *state, struct mbuf *dmsg)); -static int bsd_decompress __P((void *state, struct mbuf *cmp, - struct mbuf **dmpp)); -static void bsd_reset __P((void *state)); -static void bsd_comp_stats __P((void *state, struct compstat *stats)); - -/* - * Procedures exported to if_ppp.c. - */ -struct compressor ppp_bsd_compress = { - CI_BSD_COMPRESS, /* compress_proto */ - bsd_comp_alloc, /* comp_alloc */ - bsd_free, /* comp_free */ - bsd_comp_init, /* comp_init */ - bsd_reset, /* comp_reset */ - bsd_compress, /* compress */ - bsd_comp_stats, /* comp_stat */ - bsd_decomp_alloc, /* decomp_alloc */ - bsd_free, /* decomp_free */ - bsd_decomp_init, /* decomp_init */ - bsd_reset, /* decomp_reset */ - bsd_decompress, /* decompress */ - bsd_incomp, /* incomp */ - bsd_comp_stats, /* decomp_stat */ -}; - -/* - * 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(BSD_MAX_BITS) - -#define BSD_HASH(prefix,suffix,hshift) ((((u_int32_t)(suffix)) << (hshift)) \ - ^ (u_int32_t)(prefix)) -#define BSD_KEY(prefix,suffix) ((((u_int32_t)(suffix)) << 16) \ - + (u_int32_t)(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) - -static void bsd_clear __P((struct bsd_db *)); -static int bsd_check __P((struct bsd_db *)); -static void *bsd_alloc __P((u_char *, int, int)); -static int bsd_init __P((struct bsd_db *, u_char *, int, int, int, int, - int, int)); - -/* - * clear the dictionary - */ -static void -bsd_clear(db) - struct bsd_db *db; -{ - db->clear_count++; - db->max_ent = FIRST-1; - db->n_bits = BSD_INIT_BITS; - db->ratio = 0; - db->bytes_out = 0; - db->in_count = 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 /* 1=output CLEAR */ -bsd_check(db) - struct bsd_db *db; -{ - u_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/4; - db->bytes_out -= db->bytes_out/4; - } - - 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(state, stats) - void *state; - struct compstat *stats; -{ - struct bsd_db *db = (struct bsd_db *) state; - u_int out; - - 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->ratio = db->in_count; - out = db->bytes_out; - if (stats->ratio <= 0x7fffff) - stats->ratio <<= 8; - else - out >>= 8; - if (out != 0) - stats->ratio /= out; -} - -/* - * Reset state, as on a CCP ResetReq. - */ -static void -bsd_reset(state) - void *state; -{ - struct bsd_db *db = (struct bsd_db *) state; - - db->seqno = 0; - bsd_clear(db); - db->clear_count = 0; -} - -/* - * Allocate space for a (de) compressor. - */ -static void * -bsd_alloc(options, opt_len, decomp) - u_char *options; - int opt_len, decomp; -{ - int bits; - u_int newlen, hsize, hshift, maxmaxcode; - struct bsd_db *db; - - if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS - || options[1] != CILEN_BSD_COMPRESS - || 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; - } - - maxmaxcode = MAXCODE(bits); - newlen = sizeof(*db) + (hsize-1) * (sizeof(db->dict[0])); - MALLOC(db, struct bsd_db *, newlen, M_DEVBUF, M_NOWAIT); - if (!db) - return NULL; - bzero(db, sizeof(*db) - sizeof(db->dict)); - - if (!decomp) { - db->lens = NULL; - } else { - MALLOC(db->lens, u_int16_t *, (maxmaxcode+1) * sizeof(db->lens[0]), - M_DEVBUF, M_NOWAIT); - if (!db->lens) { - FREE(db, M_DEVBUF); - return NULL; - } - } - - db->totlen = newlen; - db->hsize = hsize; - db->hshift = hshift; - db->maxmaxcode = maxmaxcode; - db->maxbits = bits; - - return (void *) db; -} - -static void -bsd_free(state) - void *state; -{ - struct bsd_db *db = (struct bsd_db *) state; - - if (db->lens) - FREE(db->lens, M_DEVBUF); - FREE(db, M_DEVBUF); -} - -static void * -bsd_comp_alloc(options, opt_len) - u_char *options; - int opt_len; -{ - return bsd_alloc(options, opt_len, 0); -} - -static void * -bsd_decomp_alloc(options, opt_len) - u_char *options; - int opt_len; -{ - return bsd_alloc(options, opt_len, 1); -} - -/* - * Initialize the database. - */ -static int -bsd_init(db, options, opt_len, unit, hdrlen, mru, debug, decomp) - struct bsd_db *db; - u_char *options; - int opt_len, unit, hdrlen, mru, debug, decomp; -{ - int i; - - if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS - || options[1] != CILEN_BSD_COMPRESS - || BSD_VERSION(options[2]) != BSD_CURRENT_VERSION - || BSD_NBITS(options[2]) != db->maxbits - || (decomp && db->lens == NULL)) - return 0; - - if (decomp) { - i = LAST+1; - while (i != 0) - db->lens[--i] = 1; - } - i = db->hsize; - while (i != 0) { - db->dict[--i].codem1 = BADCODEM1; - db->dict[i].cptr = 0; - } - - db->unit = unit; - db->hdrlen = hdrlen; - db->mru = mru; -#ifndef DEBUG - if (debug) -#endif - db->debug = 1; - - bsd_reset(db); - - return 1; -} - -static int -bsd_comp_init(state, options, opt_len, unit, hdrlen, debug) - void *state; - u_char *options; - int opt_len, unit, hdrlen, debug; -{ - return bsd_init((struct bsd_db *) state, options, opt_len, - unit, hdrlen, 0, debug, 0); -} - -static int -bsd_decomp_init(state, options, opt_len, unit, hdrlen, mru, debug) - void *state; - u_char *options; - int opt_len, unit, hdrlen, mru, debug; -{ - return bsd_init((struct bsd_db *) state, options, opt_len, - unit, hdrlen, mru, debug, 1); -} - - -/* - * compress a packet - * One change from the BSD compress command is that when the - * code size expands, we do not output a bunch of padding. - */ -int /* new slen */ -bsd_compress(state, mret, mp, slen, maxolen) - void *state; - struct mbuf **mret; /* return compressed mbuf chain here */ - struct mbuf *mp; /* from here */ - int slen; /* uncompressed length */ - int maxolen; /* max compressed length */ -{ - struct bsd_db *db = (struct bsd_db *) state; - int hshift = db->hshift; - u_int max_ent = db->max_ent; - u_int n_bits = db->n_bits; - u_int bitno = 32; - u_int32_t accm = 0, fcode; - struct bsd_dict *dictp; - u_char c; - int hval, disp, ent, ilen; - u_char *rptr, *wptr; - u_char *cp_end; - int olen; - struct mbuf *m; - -#define PUTBYTE(v) { \ - ++olen; \ - if (wptr) { \ - *wptr++ = (v); \ - if (wptr >= cp_end) { \ - m->m_len = wptr - mtod(m, u_char *); \ - MGET(m->m_next, M_DONTWAIT, MT_DATA); \ - m = m->m_next; \ - if (m) { \ - m->m_len = 0; \ - if (maxolen - olen > MLEN) \ - MCLGET(m, M_DONTWAIT); \ - wptr = mtod(m, u_char *); \ - cp_end = wptr + M_TRAILINGSPACE(m); \ - } else \ - 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. - */ - rptr = mtod(mp, u_char *); - ent = PPP_PROTOCOL(rptr); - if (ent < 0x21 || ent > 0xf9) { - *mret = NULL; - return slen; - } - - /* Don't generate compressed packets which are larger than - the uncompressed packet. */ - if (maxolen > slen) - maxolen = slen; - - /* Allocate one mbuf to start with. */ - MGET(m, M_DONTWAIT, MT_DATA); - *mret = m; - if (m != NULL) { - m->m_len = 0; - if (maxolen + db->hdrlen > MLEN) - MCLGET(m, M_DONTWAIT); - m->m_data += db->hdrlen; - wptr = mtod(m, u_char *); - cp_end = wptr + M_TRAILINGSPACE(m); - } else - wptr = cp_end = NULL; - - /* - * Copy the PPP header over, changing the protocol, - * and install the 2-byte packet sequence number. - */ - if (wptr) { - *wptr++ = PPP_ADDRESS(rptr); /* assumes the ppp header is */ - *wptr++ = PPP_CONTROL(rptr); /* all in one mbuf */ - *wptr++ = 0; /* change the protocol */ - *wptr++ = PPP_COMP; - *wptr++ = db->seqno >> 8; - *wptr++ = db->seqno; - } - ++db->seqno; - - olen = 0; - rptr += PPP_HDRLEN; - slen = mp->m_len - PPP_HDRLEN; - ilen = slen + 1; - for (;;) { - if (slen <= 0) { - mp = mp->m_next; - if (!mp) - break; - rptr = mtod(mp, u_char *); - slen = mp->m_len; - if (!slen) - continue; /* handle 0-length buffers */ - ilen += slen; - } - - slen--; - c = *rptr++; - fcode = BSD_KEY(ent, c); - hval = BSD_HASH(ent, c, hshift); - dictp = &db->dict[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 = &db->dict[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; - /* expand code size if needed */ - if (max_ent >= MAXCODE(n_bits)) - db->n_bits = ++n_bits; - - /* Invalidate old hash table entry using - * this code, and then take it over. - */ - dictp2 = &db->dict[max_ent+1]; - if (db->dict[dictp2->cptr].codem1 == max_ent) - db->dict[dictp2->cptr].codem1 = BADCODEM1; - dictp2->cptr = hval; - dictp->codem1 = max_ent; - dictp->f.fcode = fcode; - - db->max_ent = ++max_ent; - } - ent = c; - } - - OUTPUT(ent); /* output the last code */ - db->bytes_out += olen; - db->in_count += ilen; - if (bitno < 32) - ++db->bytes_out; /* count complete bytes */ - - if (bsd_check(db)) - OUTPUT(CLEAR); /* do not count the 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); - - if (m != NULL) { - m->m_len = wptr - mtod(m, u_char *); - m->m_next = NULL; - } - - /* - * Increase code size if we would have without the packet - * boundary and as the decompressor will. - */ - if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) - db->n_bits++; - - db->uncomp_bytes += ilen; - ++db->uncomp_count; - if (olen + PPP_HDRLEN + BSD_OVHD > maxolen) { - /* throw away the compressed stuff if it is longer than uncompressed */ - if (*mret != NULL) { - m_freem(*mret); - *mret = NULL; - } - ++db->incomp_count; - db->incomp_bytes += ilen; - } else { - ++db->comp_count; - db->comp_bytes += olen + BSD_OVHD; - } - - return olen + PPP_HDRLEN + BSD_OVHD; -#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(state, dmsg) - void *state; - struct mbuf *dmsg; -{ - struct bsd_db *db = (struct bsd_db *) state; - u_int hshift = db->hshift; - u_int max_ent = db->max_ent; - u_int n_bits = db->n_bits; - struct bsd_dict *dictp; - u_int32_t fcode; - u_char c; - u_int32_t hval, disp; - int slen, ilen; - u_int bitno = 7; - u_char *rptr; - u_int ent; - - /* - * If the protocol is not in the range we're interested in, - * just return without looking at the packet. If it is, - * the protocol becomes the first byte to "compress". - */ - rptr = mtod(dmsg, u_char *); - ent = PPP_PROTOCOL(rptr); - if (ent < 0x21 || ent > 0xf9) - return; - - db->seqno++; - ilen = 1; /* count the protocol as 1 byte */ - rptr += PPP_HDRLEN; - slen = dmsg->m_len - PPP_HDRLEN; - for (;;) { - if (slen <= 0) { - dmsg = dmsg->m_next; - if (!dmsg) - break; - rptr = mtod(dmsg, u_char *); - slen = dmsg->m_len; - continue; - } - ilen += slen; - - do { - c = *rptr++; - fcode = BSD_KEY(ent, c); - hval = BSD_HASH(ent, c, hshift); - dictp = &db->dict[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 = &db->dict[hval]; - if (dictp->codem1 >= max_ent) - goto nomatch; - } while (dictp->f.fcode != fcode); - ent = dictp->codem1+1; - continue; /* finally found (prefix,suffix) */ - - nomatch: /* output (count) the prefix */ - bitno += n_bits; - - /* code -> hashtable */ - if (max_ent < db->maxmaxcode) { - struct bsd_dict *dictp2; - /* expand code size if needed */ - if (max_ent >= MAXCODE(n_bits)) - db->n_bits = ++n_bits; - - /* Invalidate previous hash table entry - * assigned this code, and then take it over. - */ - dictp2 = &db->dict[max_ent+1]; - if (db->dict[dictp2->cptr].codem1 == max_ent) - db->dict[dictp2->cptr].codem1 = BADCODEM1; - dictp2->cptr = hval; - dictp->codem1 = max_ent; - dictp->f.fcode = fcode; - - db->max_ent = ++max_ent; - db->lens[max_ent] = db->lens[ent]+1; - } - ent = c; - } while (--slen != 0); - } - bitno += n_bits; /* output (count) the last code */ - db->bytes_out += bitno/8; - db->in_count += ilen; - (void)bsd_check(db); - - ++db->incomp_count; - db->incomp_bytes += ilen; - ++db->uncomp_count; - db->uncomp_bytes += ilen; - - /* Increase code size if we would have without the packet - * boundary and as the decompressor will. - */ - if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) - db->n_bits++; -} - - -/* - * 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. - */ -int -bsd_decompress(state, cmp, dmpp) - void *state; - struct mbuf *cmp, **dmpp; -{ - struct bsd_db *db = (struct bsd_db *) state; - u_int max_ent = db->max_ent; - u_int32_t accm = 0; - u_int bitno = 32; /* 1st valid bit in accm */ - u_int n_bits = db->n_bits; - u_int tgtbitno = 32-n_bits; /* bitno when we have a code */ - struct bsd_dict *dictp; - int explen, i, seq, len; - u_int incode, oldcode, finchar; - u_char *p, *rptr, *wptr; - struct mbuf *m, *dmp, *mret; - int adrs, ctrl, ilen; - int space, codelen, extra; - - /* - * Save the address/control from the PPP header - * and then get the sequence number. - */ - *dmpp = NULL; - rptr = mtod(cmp, u_char *); - adrs = PPP_ADDRESS(rptr); - ctrl = PPP_CONTROL(rptr); - rptr += PPP_HDRLEN; - len = cmp->m_len - PPP_HDRLEN; - seq = 0; - for (i = 0; i < 2; ++i) { - while (len <= 0) { - cmp = cmp->m_next; - if (cmp == NULL) - return DECOMP_ERROR; - rptr = mtod(cmp, u_char *); - len = cmp->m_len; - } - seq = (seq << 8) + *rptr++; - --len; - } - - /* - * Check the sequence number and give up if it differs from - * the value we're expecting. - */ - if (seq != db->seqno) { - if (db->debug) - printf("bsd_decomp%d: bad sequence # %d, expected %d\n", - db->unit, seq, db->seqno - 1); - return DECOMP_ERROR; - } - ++db->seqno; - - /* - * Allocate one mbuf to start with. - */ - MGETHDR(dmp, M_DONTWAIT, MT_DATA); - if (dmp == NULL) - return DECOMP_ERROR; - mret = dmp; - dmp->m_len = 0; - dmp->m_next = NULL; - MCLGET(dmp, M_DONTWAIT); - dmp->m_data += db->hdrlen; - wptr = mtod(dmp, u_char *); - space = M_TRAILINGSPACE(dmp) - PPP_HDRLEN + 1; - - /* - * Fill in the ppp header, but not the last byte of the protocol - * (that comes from the decompressed data). - */ - wptr[0] = adrs; - wptr[1] = ctrl; - wptr[2] = 0; - wptr += PPP_HDRLEN - 1; - - ilen = len; - oldcode = CLEAR; - explen = 0; - for (;;) { - if (len == 0) { - cmp = cmp->m_next; - if (!cmp) /* quit at end of message */ - break; - rptr = mtod(cmp, u_char *); - len = cmp->m_len; - ilen += len; - continue; /* handle 0-length buffers */ - } - - /* - * 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 |= *rptr++ << bitno; - --len; - if (tgtbitno < bitno) - continue; - incode = accm >> tgtbitno; - accm <<= n_bits; - bitno += n_bits; - - if (incode == CLEAR) { - /* - * The dictionary must only be cleared at - * the end of a packet. But there could be an - * empty mbuf at the end. - */ - if (len > 0 || cmp->m_next != NULL) { - while ((cmp = cmp->m_next) != NULL) - len += cmp->m_len; - if (len > 0) { - m_freem(mret); - if (db->debug) - printf("bsd_decomp%d: bad CLEAR\n", db->unit); - return DECOMP_FATALERROR; /* probably a bug */ - } - } - bsd_clear(db); - explen = ilen = 0; - break; - } - - if (incode > max_ent + 2 || incode > db->maxmaxcode - || (incode > max_ent && oldcode == CLEAR)) { - m_freem(mret); - if (db->debug) { - printf("bsd_decomp%d: bad code 0x%x oldcode=0x%x ", - db->unit, incode, oldcode); - printf("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 = db->lens[finchar]; - explen += codelen + extra; - if (explen > db->mru + 1) { - m_freem(mret); - if (db->debug) { - printf("bsd_decomp%d: ran out of mru\n", db->unit); -#ifdef DEBUG - while ((cmp = cmp->m_next) != NULL) - len += cmp->m_len; - printf(" len=%d, finchar=0x%x, codelen=%d, explen=%d\n", - len, finchar, codelen, explen); -#endif - } - return DECOMP_FATALERROR; - } - - /* - * For simplicity, the decoded characters go in a single mbuf, - * so we allocate a single extra cluster mbuf if necessary. - */ - if ((space -= codelen + extra) < 0) { - dmp->m_len = wptr - mtod(dmp, u_char *); - MGET(m, M_DONTWAIT, MT_DATA); - if (m == NULL) { - m_freem(mret); - return DECOMP_ERROR; - } - m->m_len = 0; - m->m_next = NULL; - dmp->m_next = m; - MCLGET(m, M_DONTWAIT); - space = M_TRAILINGSPACE(m) - (codelen + extra); - if (space < 0) { - /* now that's what I call *compression*. */ - m_freem(mret); - return DECOMP_ERROR; - } - dmp = m; - wptr = mtod(dmp, u_char *); - } - - /* - * Decode this code and install it in the decompressed buffer. - */ - p = (wptr += codelen); - while (finchar > LAST) { - dictp = &db->dict[db->dict[finchar].cptr]; -#ifdef DEBUG - if (--codelen <= 0 || dictp->codem1 != finchar-1) - goto bad; -#endif - *--p = dictp->f.hs.suffix; - finchar = dictp->f.hs.prefix; - } - *--p = finchar; - -#ifdef DEBUG - if (--codelen != 0) - printf("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; - u_int32_t fcode; - u_int32_t hval, disp; - - fcode = BSD_KEY(oldcode,finchar); - hval = BSD_HASH(oldcode,finchar,db->hshift); - dictp = &db->dict[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 = &db->dict[hval]; - } while (dictp->codem1 < max_ent); - } - - /* - * Invalidate previous hash table entry - * assigned this code, and then take it over - */ - dictp2 = &db->dict[max_ent+1]; - if (db->dict[dictp2->cptr].codem1 == max_ent) { - db->dict[dictp2->cptr].codem1 = BADCODEM1; - } - dictp2->cptr = hval; - dictp->codem1 = max_ent; - dictp->f.fcode = fcode; - - db->max_ent = ++max_ent; - db->lens[max_ent] = db->lens[oldcode]+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; - } - dmp->m_len = wptr - mtod(dmp, u_char *); - - /* - * Keep the checkpoint right so that incompressible packets - * clear the dictionary at the right times. - */ - db->bytes_out += ilen; - db->in_count += explen; - if (bsd_check(db) && db->debug) { - printf("bsd_decomp%d: peer should have cleared dictionary\n", - db->unit); - } - - ++db->comp_count; - db->comp_bytes += ilen + BSD_OVHD; - ++db->uncomp_count; - db->uncomp_bytes += explen; - - *dmpp = mret; - return DECOMP_OK; - -#ifdef DEBUG - bad: - if (codelen <= 0) { - printf("bsd_decomp%d: fell off end of chain ", db->unit); - printf("0x%x at 0x%x by 0x%x, max_ent=0x%x\n", - incode, finchar, db->dict[finchar].cptr, max_ent); - } else if (dictp->codem1 != finchar-1) { - printf("bsd_decomp%d: bad code chain 0x%x finchar=0x%x ", - db->unit, incode, finchar); - printf("oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode, - db->dict[finchar].cptr, dictp->codem1); - } - m_freem(mret); - return DECOMP_FATALERROR; -#endif /* DEBUG */ -} -#endif /* DO_BSD_COMPRESS */ |