diff options
Diffstat (limited to 'drivers/isdn/i4l/isdn_bsdcomp.c')
| -rw-r--r-- | drivers/isdn/i4l/isdn_bsdcomp.c | 930 |
1 files changed, 0 insertions, 930 deletions
diff --git a/drivers/isdn/i4l/isdn_bsdcomp.c b/drivers/isdn/i4l/isdn_bsdcomp.c deleted file mode 100644 index 7f28b967ed19..000000000000 --- a/drivers/isdn/i4l/isdn_bsdcomp.c +++ /dev/null @@ -1,930 +0,0 @@ -/* - * BSD compression module - * - * Patched version for ISDN syncPPP written 1997/1998 by Michael Hipp - * The whole module is now SKB based. - * - */ - -/* - * 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.. - */ - -/* - * Original copyright notice: - * - * 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. - */ - -#include <linux/module.h> -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/types.h> -#include <linux/fcntl.h> -#include <linux/interrupt.h> -#include <linux/ptrace.h> -#include <linux/ioport.h> -#include <linux/in.h> -#include <linux/slab.h> -#include <linux/tty.h> -#include <linux/errno.h> -#include <linux/string.h> /* used in new tty drivers */ -#include <linux/signal.h> /* used in new tty drivers */ -#include <linux/bitops.h> - -#include <asm/byteorder.h> -#include <asm/types.h> - -#include <linux/if.h> - -#include <linux/if_ether.h> -#include <linux/netdevice.h> -#include <linux/skbuff.h> -#include <linux/inet.h> -#include <linux/ioctl.h> -#include <linux/vmalloc.h> - -#include <linux/ppp_defs.h> - -#include <linux/isdn.h> -#include <linux/isdn_ppp.h> -#include <linux/ip.h> -#include <linux/tcp.h> -#include <linux/if_arp.h> -#include <linux/ppp-comp.h> - -#include "isdn_ppp.h" - -MODULE_DESCRIPTION("ISDN4Linux: BSD Compression for PPP over ISDN"); -MODULE_LICENSE("Dual BSD/GPL"); - -#define BSD_VERSION(x) ((x) >> 5) -#define BSD_NBITS(x) ((x) & 0x1F) - -#define BSD_CURRENT_VERSION 1 - -#define DEBUG 1 - -/* - * A dictionary for doing BSD compress. - */ - -struct bsd_dict { - u32 fcode; - u16 codem1; /* output of hash table -1 */ - u16 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 */ - u16 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 */ - int xmit; -}; - -#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 - -/* - * 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->incomp_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_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, unsigned char code, unsigned char id, - unsigned char *data, unsigned len, - struct isdn_ppp_resetparams *rsparm) -{ - 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 = (struct bsd_db *) state; - - if (db) { - /* - * 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(struct isdn_ppp_comp_data *data) -{ - int bits; - unsigned int hsize, hshift, maxmaxcode; - struct bsd_db *db; - int decomp; - - static unsigned int htab[][2] = { - { 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } , - { 9001 , 5 } , { 18013 , 6 } , { 35023 , 7 } , { 69001 , 8 } - }; - - if (data->optlen != 1 || data->num != CI_BSD_COMPRESS - || BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION) - return NULL; - - bits = BSD_NBITS(data->options[0]); - - if (bits < 9 || bits > 15) - return NULL; - - hsize = htab[bits - 9][0]; - hshift = htab[bits - 9][1]; - - /* - * Allocate the main control structure for this instance. - */ - maxmaxcode = MAXCODE(bits); - db = kzalloc(sizeof(struct bsd_db), GFP_KERNEL); - if (!db) - return NULL; - - db->xmit = data->flags & IPPP_COMP_FLAG_XMIT; - decomp = db->xmit ? 0 : 1; - - /* - * 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. - * For decompression, the length information is needed as well. - */ - if (!decomp) - db->lens = NULL; - 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; -} - -/* - * Initialize the database. - */ -static int bsd_init(void *state, struct isdn_ppp_comp_data *data, int unit, int debug) -{ - struct bsd_db *db = state; - int indx; - int decomp; - - if (!state || !data) { - printk(KERN_ERR "isdn_bsd_init: [%d] ERR, state %lx data %lx\n", unit, (long)state, (long)data); - return 0; - } - - decomp = db->xmit ? 0 : 1; - - if (data->optlen != 1 || data->num != CI_BSD_COMPRESS - || (BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION) - || (BSD_NBITS(data->options[0]) != db->maxbits) - || (decomp && db->lens == NULL)) { - printk(KERN_ERR "isdn_bsd: %d %d %d %d %lx\n", data->optlen, data->num, data->options[0], decomp, (unsigned long)db->lens); - return 0; - } - - if (decomp) - for (indx = LAST; indx >= 0; indx--) - db->lens[indx] = 1; - - indx = db->hsize; - while (indx-- != 0) { - db->dict[indx].codem1 = BADCODEM1; - db->dict[indx].cptr = 0; - } - - db->unit = unit; - db->mru = 0; - - db->debug = 1; - - bsd_reset(db, 0, 0, NULL, 0, NULL); - - return 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(KERN_DEBUG "<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(KERN_DEBUG "<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 - */ -static int bsd_compress(void *state, struct sk_buff *skb_in, struct sk_buff *skb_out, int proto) -{ - 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, disp, ilen, mxcode; - unsigned char *rptr = skb_in->data; - int isize = skb_in->len; - -#define OUTPUT(ent) \ - { \ - bitno -= n_bits; \ - accm |= ((ent) << bitno); \ - do { \ - if (skb_out && skb_tailroom(skb_out) > 0) \ - skb_put_u8(skb_out, (u8)(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. - */ - printk(KERN_DEBUG "bsd_compress called with %x\n", proto); - - ent = proto; - if (proto < 0x21 || proto > 0xf9 || !(proto & 0x1)) - 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); - - /* This is the PPP header information */ - if (skb_out && skb_tailroom(skb_out) >= 2) { - char *v = skb_put(skb_out, 2); - /* we only push our own data on the header, - AC,PC and protos is pushed by caller */ - v[0] = db->seqno >> 8; - v[1] = db->seqno; - } - - ilen = ++isize; /* This is off by one, but that is what is in draft! */ - - 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->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->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->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 */ - - if (skb_out) - db->bytes_out += skb_out->len; /* Do not count bytes from here */ - 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 && skb_out && skb_tailroom(skb_out) > 0) - skb_put_u8(skb_out, - (unsigned char)((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 incompressible frame. */ - if (!skb_out || skb_out->len >= skb_in->len) { - ++db->incomp_count; - db->incomp_bytes += isize; - return 0; - } - - /* Count the number of compressed frames */ - ++db->comp_count; - db->comp_bytes += skb_out->len; - return skb_out->len; - -#undef OUTPUT -} - -/* - * Update the "BSD Compress" dictionary on the receiver for - * incompressible data by pretending to compress the incoming data. - */ -static void bsd_incomp(void *state, struct sk_buff *skb_in, int proto) -{ - bsd_compress(state, skb_in, NULL, proto); -} - -/* - * Decompress "BSD Compress". - */ -static int bsd_decompress(void *state, struct sk_buff *skb_in, struct sk_buff *skb_out, - struct isdn_ppp_resetparams *rsparm) -{ - 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 seq; - unsigned int incode; - unsigned int oldcode; - unsigned int finchar; - unsigned char *p, *ibuf; - 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 */ - - printk(KERN_DEBUG "bsd_decompress called\n"); - - if (!skb_in || !skb_out) { - printk(KERN_ERR "bsd_decompress called with NULL parameter\n"); - return DECOMP_ERROR; - } - - /* - * Get the sequence number. - */ - if ((p = skb_pull(skb_in, 2)) == NULL) { - return DECOMP_ERROR; - } - p -= 2; - seq = (p[0] << 8) + p[1]; - ilen = skb_in->len; - ibuf = skb_in->data; - - /* - * Check the sequence number and give up if it differs from - * the value we're expecting. - */ - if (seq != db->seqno) { - if (db->debug) { - printk(KERN_DEBUG "bsd_decomp%d: bad sequence # %d, expected %d\n", - db->unit, seq, db->seqno - 1); - } - return DECOMP_ERROR; - } - - ++db->seqno; - db->bytes_out += ilen; - - if (skb_tailroom(skb_out) > 0) - skb_put_u8(skb_out, 0); - else - return DECOMP_ERR_NOMEM; - - oldcode = CLEAR; - - /* - * Keep the checkpoint correctly so that incompressible packets - * clear the dictionary at the proper times. - */ - - for (;;) { - if (ilen-- <= 0) { - db->in_count += (skb_out->len - 1); /* 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(KERN_DEBUG "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(KERN_DEBUG "bsd_decomp%d: bad code 0x%x oldcode=0x%x ", - db->unit, incode, oldcode); - printk(KERN_DEBUG "max_ent=0x%x skb->Len=%d seqno=%d\n", - max_ent, skb_out->len, 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)); - if (skb_tailroom(skb_out) < codelen + extra) { - if (db->debug) { - printk(KERN_DEBUG "bsd_decomp%d: ran out of mru\n", db->unit); -#ifdef DEBUG - printk(KERN_DEBUG " len=%d, finchar=0x%x, codelen=%d,skblen=%d\n", - ilen, finchar, codelen, skb_out->len); -#endif - } - return DECOMP_FATALERROR; - } - - /* - * Decode this code and install it in the decompressed buffer. - */ - - p = skb_put(skb_out, codelen); - p += codelen; - 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(KERN_ERR "bsd_decomp%d: fell off end of chain ", db->unit); - printk(KERN_ERR "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(KERN_ERR "bsd_decomp%d: bad code chain 0x%x finchar=0x%x ", db->unit, incode, finchar); - printk(KERN_ERR "oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode, dictp2->cptr, dictp->codem1); - } - } - return DECOMP_FATALERROR; - } -#endif - - { - u32 fcode = dictp->fcode; - *--p = (fcode >> 16) & 0xff; - finchar = fcode & 0xffff; - } - } - *--p = finchar; - -#ifdef DEBUG - if (--codelen != 0) - printk(KERN_ERR "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 */ - skb_put_u8(skb_out, 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; - u16 *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->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 += skb_in->len - BSD_OVHD; - db->uncomp_bytes += skb_out->len; - - if (bsd_check(db)) { - if (db->debug) - printk(KERN_DEBUG "bsd_decomp%d: peer should have cleared dictionary on %d\n", - db->unit, db->seqno - 1); - } - return skb_out->len; -} - -/************************************************************* - * Table of addresses for the BSD compression module - *************************************************************/ - -static struct isdn_ppp_compressor ippp_bsd_compress = { - .owner = THIS_MODULE, - .num = CI_BSD_COMPRESS, - .alloc = bsd_alloc, - .free = bsd_free, - .init = bsd_init, - .reset = bsd_reset, - .compress = bsd_compress, - .decompress = bsd_decompress, - .incomp = bsd_incomp, - .stat = bsd_stats, -}; - -/************************************************************* - * Module support routines - *************************************************************/ - -static int __init isdn_bsdcomp_init(void) -{ - int answer = isdn_ppp_register_compressor(&ippp_bsd_compress); - if (answer == 0) - printk(KERN_INFO "PPP BSD Compression module registered\n"); - return answer; -} - -static void __exit isdn_bsdcomp_exit(void) -{ - isdn_ppp_unregister_compressor(&ippp_bsd_compress); -} - -module_init(isdn_bsdcomp_init); -module_exit(isdn_bsdcomp_exit); |