Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 937 insertions, 0 deletions

diff --git a/drivers/isdn/i4l/isdn_bsdcomp.c b/drivers/isdn/i4l/isdn_bsdcomp.c
new file mode 100644
index 000000000000..baf4bcad9bf9
--- /dev/null
+++ b/drivers/isdn/i4l/isdn_bsdcomp.c
@@ -0,0 +1,937 @@
+/*
+ * 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/sched.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/system.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
+                 */
+                if (db->dict) {
+                        vfree (db->dict);
+                        db->dict = NULL;
+                }
+
+                /*
+                 * Release the string buffer
+                 */
+                if (db->lens) {
+                        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 = (struct bsd_db *) kmalloc (sizeof (struct bsd_db),GFP_KERNEL);
+        if (!db)
+                return NULL;
+
+        memset (db, 0, sizeof(struct bsd_db));
+
+        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 = (struct bsd_dict *) vmalloc (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 = (unsigned short *) vmalloc ((maxmaxcode + 1) *
+                        sizeof (db->lens[0]));
+                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(skb_out,1)) = (unsigned char) (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(skb_out,1)) = (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 && 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(skb_out,1)) = 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(skb_out,1)) = 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);