Update from Steve Perkins
[ppp.git] / linux / ppp_deflate.c
index 3de45971c6fbe70bf288740242d705afd4de16d0..a812eea6ca559baea32986eba8244cb9bfd2f50e 100644 (file)
@@ -1,9 +1,9 @@
 /*
- *  ==FILEVERSION 970522==
+ *  ==FILEVERSION 980319==
  *
  * ppp_deflate.c - interface the zlib procedures for Deflate compression
  * and decompression (as used by gzip) to the PPP code.
- * This version is for use with Linux kernel 1.3.X.
+ * This version is for use with Linux kernel 1.3.X and later.
  *
  * Copyright (c) 1994 The Australian National University.
  * All rights reserved.
@@ -86,7 +86,7 @@ struct ppp_deflate_state {
 static void    *zalloc __P((void *, unsigned int items, unsigned int size));
 static void    *zalloc_init __P((void *, unsigned int items,
                                  unsigned int size));
-static void    zfree __P((void *, void *ptr, unsigned int nb));
+static void    zfree __P((void *, void *ptr));
 static void    *z_comp_alloc __P((unsigned char *options, int opt_len));
 static void    *z_decomp_alloc __P((unsigned char *options, int opt_len));
 static void    z_comp_free __P((void *state));
@@ -108,27 +108,32 @@ static void       z_decomp_reset __P((void *state));
 static void    z_comp_stats __P((void *state, struct compstat *stats));
 
 struct chunk_header {
-    unsigned size;             /* amount of space following header */
-    int valloced;              /* allocated with valloc, not kmalloc */
+       int valloced;           /* allocated with valloc, not kmalloc */
+       int guard;              /* check for overwritten header */
 };
 
+#define GUARD_MAGIC    0x77a8011a
 #define MIN_VMALLOC    2048    /* use kmalloc for blocks < this */
 
 /*
  * Space allocation and freeing routines for use by zlib routines.
  */
 void
-zfree(arg, ptr, nbytes)
+zfree(arg, ptr)
     void *arg;
     void *ptr;
-    unsigned int nbytes;
 {
-    struct chunk_header *hdr = ((struct chunk_header *)ptr) - 1;
+       struct chunk_header *hdr = ((struct chunk_header *)ptr) - 1;
 
-    if (hdr->valloced)
-       vfree(hdr);
-    else
-       kfree(hdr);
+       if (hdr->guard != GUARD_MAGIC) {
+               printk(KERN_WARNING "zfree: header corrupted (%x %x) at %p\n",
+                      hdr->valloced, hdr->guard, hdr);
+               return;
+       }
+       if (hdr->valloced)
+               vfree(hdr);
+       else
+               kfree(hdr);
 }
 
 void *
@@ -136,16 +141,16 @@ zalloc(arg, items, size)
     void *arg;
     unsigned int items, size;
 {
-    struct chunk_header *hdr;
-    unsigned nbytes;
-
-    nbytes = items * size + sizeof(*hdr);
-    hdr = kmalloc(nbytes, GFP_ATOMIC);
-    if (hdr == 0)
-       return 0;
-    hdr->size = nbytes;
-    hdr->valloced = 0;
-    return (void *) (hdr + 1);
+       struct chunk_header *hdr;
+       unsigned nbytes;
+
+       nbytes = items * size + sizeof(*hdr);
+       hdr = kmalloc(nbytes, GFP_ATOMIC);
+       if (hdr == 0)
+               return 0;
+       hdr->valloced = 0;
+       hdr->guard = GUARD_MAGIC;
+       return (void *) (hdr + 1);
 }
 
 void *
@@ -153,32 +158,32 @@ zalloc_init(arg, items, size)
     void *arg;
     unsigned int items, size;
 {
-    struct chunk_header *hdr;
-    unsigned nbytes;
-
-    nbytes = items * size + sizeof(*hdr);
-    if (nbytes >= MIN_VMALLOC)
-       hdr = vmalloc(nbytes);
-    else
-       hdr = kmalloc(nbytes, GFP_KERNEL);
-    if (hdr == 0)
-       return 0;
-    hdr->size = nbytes;
-    hdr->valloced = nbytes >= MIN_VMALLOC;
-    return (void *) (hdr + 1);
+       struct chunk_header *hdr;
+       unsigned nbytes;
+
+       nbytes = items * size + sizeof(*hdr);
+       if (nbytes >= MIN_VMALLOC)
+               hdr = vmalloc(nbytes);
+       else
+               hdr = kmalloc(nbytes, GFP_KERNEL);
+       if (hdr == 0)
+               return 0;
+       hdr->valloced = nbytes >= MIN_VMALLOC;
+       hdr->guard = GUARD_MAGIC;
+       return (void *) (hdr + 1);
 }
 
 static void
 z_comp_free(arg)
     void *arg;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    if (state) {
-           deflateEnd(&state->strm);
-           kfree(state);
-           MOD_DEC_USE_COUNT;
-    }
+       if (state) {
+               deflateEnd(&state->strm);
+               kfree(state);
+               MOD_DEC_USE_COUNT;
+       }
 }
 
 /*
@@ -189,36 +194,41 @@ z_comp_alloc(options, opt_len)
     unsigned char *options;
     int opt_len;
 {
-    struct ppp_deflate_state *state;
-    int w_size;
-
-    if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
-       || options[1] != CILEN_DEFLATE
-       || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
-       || options[3] != DEFLATE_CHK_SEQUENCE)
-       return NULL;
-    w_size = DEFLATE_SIZE(options[2]);
-    if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
-       return NULL;
-
-    state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
-    if (state == NULL)
-       return NULL;
-
-    MOD_INC_USE_COUNT;
-    memset (state, 0, sizeof (struct ppp_deflate_state));
-    state->strm.next_in = NULL;
-    state->strm.zalloc  = zalloc;
-    state->strm.zalloc_init = zalloc_init;
-    state->strm.zfree   = zfree;
-    state->w_size       = w_size;
-
-    if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
-                    -w_size, 8, Z_DEFAULT_STRATEGY, DEFLATE_OVHD+2) != Z_OK) {
+       struct ppp_deflate_state *state;
+       int w_size;
+
+       if (opt_len != CILEN_DEFLATE
+           || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
+           || options[1] != CILEN_DEFLATE
+           || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
+           || options[3] != DEFLATE_CHK_SEQUENCE)
+               return NULL;
+       w_size = DEFLATE_SIZE(options[2]);
+       if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+               return NULL;
+
+       state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
+       if (state == NULL)
+               return NULL;
+
+       MOD_INC_USE_COUNT;
+       memset (state, 0, sizeof (struct ppp_deflate_state));
+       state->strm.next_in = NULL;
+       state->strm.zalloc  = zalloc_init;
+       state->strm.zfree   = zfree;
+       state->w_size       = w_size;
+
+       if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
+                        DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
+           != Z_OK)
+               goto out_free;
+       state->strm.zalloc = zalloc;
+       return (void *) state;
+
+out_free:
        z_comp_free(state);
+       MOD_DEC_USE_COUNT;
        return NULL;
-    }
-    return (void *) state;
 }
 
 static int
@@ -227,32 +237,33 @@ z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
     unsigned char *options;
     int opt_len, unit, hdrlen, debug;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
-       || options[1] != CILEN_DEFLATE
-       || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
-       || DEFLATE_SIZE(options[2]) != state->w_size
-       || options[3] != DEFLATE_CHK_SEQUENCE)
-       return 0;
+       if (opt_len < CILEN_DEFLATE
+           || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
+           || options[1] != CILEN_DEFLATE
+           || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
+           || DEFLATE_SIZE(options[2]) != state->w_size
+           || options[3] != DEFLATE_CHK_SEQUENCE)
+               return 0;
 
-    state->seqno = 0;
-    state->unit  = unit;
-    state->debug = debug;
+       state->seqno = 0;
+       state->unit  = unit;
+       state->debug = debug;
 
-    deflateReset(&state->strm);
+       deflateReset(&state->strm);
 
-    return 1;
+       return 1;
 }
 
 static void
 z_comp_reset(arg)
     void *arg;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    state->seqno = 0;
-    deflateReset(&state->strm);
+       state->seqno = 0;
+       deflateReset(&state->strm);
 }
 
 int
@@ -262,81 +273,78 @@ z_compress(arg, rptr, obuf, isize, osize)
     unsigned char *obuf;       /* compressed packet (out) */
     int isize, osize;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
-    int r, proto, off, olen;
-    unsigned char *wptr;
-
-    /*
-     * Check that the protocol is in the range we handle.
-     */
-    proto = PPP_PROTOCOL(rptr);
-    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
-       return 0;
-
-    /* Don't generate compressed packets which are larger than
-       the uncompressed packet. */
-    if (osize > isize)
-       osize = isize;
-
-    wptr = obuf;
-
-    /*
-     * Copy over the PPP header and store the 2-byte sequence number.
-     */
-    wptr[0] = PPP_ADDRESS(rptr);
-    wptr[1] = PPP_CONTROL(rptr);
-    wptr[2] = PPP_COMP >> 8;
-    wptr[3] = PPP_COMP;
-    wptr += PPP_HDRLEN;
-    wptr[0] = state->seqno >> 8;
-    wptr[1] = state->seqno;
-    wptr += 2;
-    state->strm.next_out = wptr;
-    state->strm.avail_out = osize - (PPP_HDRLEN + 2);
-    ++state->seqno;
-
-    off = (proto > 0xff) ? 2 : 3;      /* skip 1st proto byte if 0 */
-    rptr += off;
-    state->strm.next_in = rptr;
-    state->strm.avail_in = (isize - off);
-
-    olen = 0;
-    for (;;) {
-       r = deflate(&state->strm, Z_PACKET_FLUSH);
-       if (r != Z_OK) {
-           if (state->debug)
-               printk(KERN_DEBUG "z_compress: deflate returned %d (%s)\n",
-                      r, (state->strm.msg? state->strm.msg: ""));
-           break;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       int r, proto, off, olen, oavail;
+       unsigned char *wptr;
+
+       /*
+        * Check that the protocol is in the range we handle.
+        */
+       proto = PPP_PROTOCOL(rptr);
+       if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+               return 0;
+
+       /* Don't generate compressed packets which are larger than
+          the uncompressed packet. */
+       if (osize > isize)
+               osize = isize;
+
+       wptr = obuf;
+
+       /*
+        * Copy over the PPP header and store the 2-byte sequence number.
+        */
+       wptr[0] = PPP_ADDRESS(rptr);
+       wptr[1] = PPP_CONTROL(rptr);
+       wptr[2] = PPP_COMP >> 8;
+       wptr[3] = PPP_COMP;
+       wptr += PPP_HDRLEN;
+       wptr[0] = state->seqno >> 8;
+       wptr[1] = state->seqno;
+       wptr += DEFLATE_OVHD;
+       olen = PPP_HDRLEN + DEFLATE_OVHD;
+       state->strm.next_out = wptr;
+       state->strm.avail_out = oavail = osize - olen;
+       ++state->seqno;
+
+       off = (proto > 0xff) ? 2 : 3;   /* skip 1st proto byte if 0 */
+       rptr += off;
+       state->strm.next_in = rptr;
+       state->strm.avail_in = (isize - off);
+
+       for (;;) {
+               r = deflate(&state->strm, Z_PACKET_FLUSH);
+               if (r != Z_OK) {
+                       if (state->debug)
+                               printk(KERN_ERR
+                                      "z_compress: deflate returned %d\n", r);
+                       break;
+               }
+               if (state->strm.avail_out == 0) {
+                       olen += oavail;
+                       state->strm.next_out = NULL;
+                       state->strm.avail_out = oavail = 1000000;
+               } else {
+                       break;          /* all done */
+               }
        }
-       if (state->strm.avail_out == 0) {
-           olen += osize;
-           state->strm.next_out = NULL;
-           state->strm.avail_out = 1000000;
+       olen += oavail - state->strm.avail_out;
+
+       /*
+        * See if we managed to reduce the size of the packet.
+        */
+       if (olen < isize) {
+               state->stats.comp_bytes += olen;
+               state->stats.comp_packets++;
        } else {
-           break;              /* all done */
+               state->stats.inc_bytes += isize;
+               state->stats.inc_packets++;
+               olen = 0;
        }
-    }
-    if (olen < osize)
-       olen += osize - state->strm.avail_out;
-
-    /*
-     * See if we managed to reduce the size of the packet.
-     * If the compressor just gave us a single zero byte, it means
-     * the packet was incompressible.
-     */
-    if (olen < isize && !(olen == PPP_HDRLEN + 3 && *wptr == 0)) {
-       state->stats.comp_bytes += olen;
-       state->stats.comp_packets++;
-    } else {
-       state->stats.inc_bytes += isize;
-       state->stats.inc_packets++;
-       olen = 0;
-    }
-    state->stats.unc_bytes += isize;
-    state->stats.unc_packets++;
+       state->stats.unc_bytes += isize;
+       state->stats.unc_packets++;
 
-    return olen;
+       return olen;
 }
 
 static void
@@ -344,25 +352,22 @@ z_comp_stats(arg, stats)
     void *arg;
     struct compstat *stats;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    *stats = state->stats;
+       *stats = state->stats;
 }
 
 static void
 z_decomp_free(arg)
     void *arg;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    if (state) {
-           inflateEnd(&state->strm);
-#if USEMEMPOOL
-           memPoolFree(&state->strm.opaque);
-#endif
-           kfree(state);
-           MOD_DEC_USE_COUNT;
-    }
+       if (state) {
+               inflateEnd(&state->strm);
+               kfree(state);
+               MOD_DEC_USE_COUNT;
+       }
 }
 
 /*
@@ -373,35 +378,39 @@ z_decomp_alloc(options, opt_len)
     unsigned char *options;
     int opt_len;
 {
-    struct ppp_deflate_state *state;
-    int w_size;
-
-    if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
-       || options[1] != CILEN_DEFLATE
-       || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
-       || options[3] != DEFLATE_CHK_SEQUENCE)
-       return NULL;
-    w_size = DEFLATE_SIZE(options[2]);
-    if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
-       return NULL;
-
-    state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
-    if (state == NULL)
-       return NULL;
-
-    MOD_INC_USE_COUNT;
-    memset (state, 0, sizeof (struct ppp_deflate_state));
-    state->w_size        = w_size;
-    state->strm.next_out = NULL;
-    state->strm.zalloc   = zalloc;
-    state->strm.zalloc_init = zalloc_init;
-    state->strm.zfree    = zfree;
-
-    if (inflateInit2(&state->strm, -w_size) != Z_OK) {
+       struct ppp_deflate_state *state;
+       int w_size;
+
+       if (opt_len != CILEN_DEFLATE
+           || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
+           || options[1] != CILEN_DEFLATE
+           || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
+           || options[3] != DEFLATE_CHK_SEQUENCE)
+               return NULL;
+       w_size = DEFLATE_SIZE(options[2]);
+       if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+               return NULL;
+
+       state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
+       if (state == NULL)
+               return NULL;
+
+       MOD_INC_USE_COUNT;
+       memset (state, 0, sizeof (struct ppp_deflate_state));
+       state->w_size        = w_size;
+       state->strm.next_out = NULL;
+       state->strm.zalloc   = zalloc_init;
+       state->strm.zfree    = zfree;
+
+       if (inflateInit2(&state->strm, -w_size) != Z_OK)
+               goto out_free;
+       state->strm.zalloc = zalloc;
+       return (void *) state;
+
+out_free:
        z_decomp_free(state);
+       MOD_DEC_USE_COUNT;
        return NULL;
-    }
-    return (void *) state;
 }
 
 static int
@@ -410,33 +419,34 @@ z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
     unsigned char *options;
     int opt_len, unit, hdrlen, mru, debug;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
-       || options[1] != CILEN_DEFLATE
-       || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
-       || DEFLATE_SIZE(options[2]) != state->w_size
-       || options[3] != DEFLATE_CHK_SEQUENCE)
-       return 0;
+       if (opt_len < CILEN_DEFLATE
+           || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
+           || options[1] != CILEN_DEFLATE
+           || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
+           || DEFLATE_SIZE(options[2]) != state->w_size
+           || options[3] != DEFLATE_CHK_SEQUENCE)
+               return 0;
 
-    state->seqno = 0;
-    state->unit  = unit;
-    state->debug = debug;
-    state->mru   = mru;
+       state->seqno = 0;
+       state->unit  = unit;
+       state->debug = debug;
+       state->mru   = mru;
 
-    inflateReset(&state->strm);
+       inflateReset(&state->strm);
 
-    return 1;
+       return 1;
 }
 
 static void
 z_decomp_reset(arg)
     void *arg;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
 
-    state->seqno = 0;
-    inflateReset(&state->strm);
+       state->seqno = 0;
+       inflateReset(&state->strm);
 }
 
 /*
@@ -463,97 +473,101 @@ z_decompress(arg, ibuf, isize, obuf, osize)
     unsigned char *obuf;
     int osize;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
-    int olen, seq, r;
-    int decode_proto, overflow;
-    unsigned char overflow_buf[1];
-
-    if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
-       if (state->debug)
-           printk(KERN_DEBUG "z_decompress%d: short packet (len=%d)\n",
-                  state->unit, isize);
-       return DECOMP_ERROR;
-    }
-
-    /* Check the sequence number. */
-    seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1];
-    if (seq != state->seqno) {
-       if (state->debug)
-           printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
-                  state->unit, seq, state->seqno);
-       return DECOMP_ERROR;
-    }
-    ++state->seqno;
-
-    /*
-     * Fill in the first part of the PPP header.  The protocol field
-     * comes from the decompressed data.
-     */
-    obuf[0] = PPP_ADDRESS(ibuf);
-    obuf[1] = PPP_CONTROL(ibuf);
-    obuf[2] = 0;
-
-    /*
-     * Set up to call inflate.  We set avail_out to 1 initially so we can
-     * look at the first byte of the output and decide whether we have
-     * a 1-byte or 2-byte protocol field.
-     */
-    state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
-    state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
-    state->strm.next_out = obuf + 3;
-    state->strm.avail_out = 1;
-    decode_proto = 1;
-    overflow = 0;
-
-    /*
-     * Call inflate, supplying more input or output as needed.
-     */
-    for (;;) {
-       r = inflate(&state->strm, Z_PACKET_FLUSH);
-       if (r != Z_OK) {
-           if (state->debug)
-               printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
-                      state->unit, r, (state->strm.msg? state->strm.msg: ""));
-           return DECOMP_FATALERROR;
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       int olen, seq, r;
+       int decode_proto, overflow;
+       unsigned char overflow_buf[1];
+
+       if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
+               if (state->debug)
+                       printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
+                              state->unit, isize);
+               return DECOMP_ERROR;
        }
-       if (state->strm.avail_out != 0)
-           break;              /* all done */
-       if (decode_proto) {
-           state->strm.avail_out = osize - PPP_HDRLEN;
-           if ((obuf[3] & 1) == 0) {
-               /* 2-byte protocol field */
-               obuf[2] = obuf[3];
-               --state->strm.next_out;
-               ++state->strm.avail_out;
-           }
-           decode_proto = 0;
-       } else if (!overflow) {
-           /*
-            * We've filled up the output buffer; the only way to
-            * find out whether inflate has any more characters left
-            * is to give it another byte of output space.
-            */
-           state->strm.next_out = overflow_buf;
-           state->strm.avail_out = 1;
-           overflow = 1;
-       } else {
-           if (state->debug)
-               printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
-                      state->unit);
-           return DECOMP_FATALERROR;
+
+       /* Check the sequence number. */
+       seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1];
+       if (seq != state->seqno) {
+               if (state->debug)
+                       printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
+                              state->unit, seq, state->seqno);
+               return DECOMP_ERROR;
+       }
+       ++state->seqno;
+
+       /*
+        * Fill in the first part of the PPP header.  The protocol field
+        * comes from the decompressed data.
+        */
+       obuf[0] = PPP_ADDRESS(ibuf);
+       obuf[1] = PPP_CONTROL(ibuf);
+       obuf[2] = 0;
+
+       /*
+        * Set up to call inflate.  We set avail_out to 1 initially so we can
+        * look at the first byte of the output and decide whether we have
+        * a 1-byte or 2-byte protocol field.
+        */
+       state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
+       state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
+       state->strm.next_out = obuf + 3;
+       state->strm.avail_out = 1;
+       decode_proto = 1;
+       overflow = 0;
+
+       /*
+        * Call inflate, supplying more input or output as needed.
+        */
+       for (;;) {
+               r = inflate(&state->strm, Z_PACKET_FLUSH);
+               if (r != Z_OK) {
+                       if (state->debug)
+                               printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
+                                      state->unit, r, (state->strm.msg? state->strm.msg: ""));
+                       return DECOMP_FATALERROR;
+               }
+               if (state->strm.avail_out != 0)
+                       break;          /* all done */
+               if (decode_proto) {
+                       state->strm.avail_out = osize - PPP_HDRLEN;
+                       if ((obuf[3] & 1) == 0) {
+                               /* 2-byte protocol field */
+                               obuf[2] = obuf[3];
+                               --state->strm.next_out;
+                               ++state->strm.avail_out;
+                       }
+                       decode_proto = 0;
+               } else if (!overflow) {
+                       /*
+                        * We've filled up the output buffer; the only way to
+                        * find out whether inflate has any more characters
+                        * left is to give it another byte of output space.
+                        */
+                       state->strm.next_out = overflow_buf;
+                       state->strm.avail_out = 1;
+                       overflow = 1;
+               } else {
+                       if (state->debug)
+                               printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
+                                      state->unit);
+                       return DECOMP_FATALERROR;
+               }
        }
-    }
 
-    if (decode_proto)
-       return DECOMP_ERROR;
+       if (decode_proto) {
+               if (state->debug)
+                       printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
+                              state->unit);
+               return DECOMP_ERROR;
+       }
 
-    olen = osize + overflow - state->strm.avail_out;
-    state->stats.unc_bytes += olen;
-    state->stats.unc_packets++;
-    state->stats.comp_bytes += isize;
-    state->stats.comp_packets++;
+       olen = osize + overflow - state->strm.avail_out;
+       state->stats.unc_bytes += olen;
+       state->stats.unc_packets++;
+       state->stats.comp_bytes += isize;
+       state->stats.comp_packets++;
 
-    return olen;
+       return olen;
 }
 
 /*
@@ -565,48 +579,46 @@ z_incomp(arg, ibuf, icnt)
     unsigned char *ibuf;
     int icnt;
 {
-    struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
-    int proto, r;
-
-    /*
-     * Check that the protocol is one we handle.
-     */
-    proto = PPP_PROTOCOL(ibuf);
-    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
-       return;
-
-    ++state->seqno;
-
-    /*
-     * Iterate through the message blocks, adding the characters in them
-     * to the decompressor's history.  For the first block, we start
-     * at the either the 1st or 2nd byte of the protocol field,
-     * depending on whether the protocol value is compressible.
-     */
-    state->strm.next_in = ibuf + 3;
-    state->strm.avail_in = icnt - 3;
-    if (proto > 0xff) {
-       --state->strm.next_in;
-       ++state->strm.avail_in;
-    }
-
-    r = inflateIncomp(&state->strm);
-    if (r != Z_OK) {
-       /* gak! */
-       if (state->debug) {
-           printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
-                  state->unit, r, (state->strm.msg? state->strm.msg: ""));
+       struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+       int proto, r;
+
+       /*
+        * Check that the protocol is one we handle.
+        */
+       proto = PPP_PROTOCOL(ibuf);
+       if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+               return;
+
+       ++state->seqno;
+
+       /*
+        * We start at the either the 1st or 2nd byte of the protocol field,
+        * depending on whether the protocol value is compressible.
+        */
+       state->strm.next_in = ibuf + 3;
+       state->strm.avail_in = icnt - 3;
+       if (proto > 0xff) {
+               --state->strm.next_in;
+               ++state->strm.avail_in;
        }
-       return;
-    }
-
-    /*
-     * Update stats.
-     */
-    state->stats.inc_bytes += icnt;
-    state->stats.inc_packets++;
-    state->stats.unc_bytes += icnt;
-    state->stats.unc_packets++;
+
+       r = inflateIncomp(&state->strm);
+       if (r != Z_OK) {
+               /* gak! */
+               if (state->debug) {
+                       printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
+                              state->unit, r, (state->strm.msg? state->strm.msg: ""));
+               }
+               return;
+       }
+
+       /*
+        * Update stats.
+        */
+       state->stats.inc_bytes += icnt;
+       state->stats.inc_packets++;
+       state->stats.unc_bytes += icnt;
+       state->stats.unc_packets++;
 }
 
 /*************************************************************
@@ -621,20 +633,37 @@ extern void ppp_unregister_compressor (struct compressor *cp);
  * Procedures exported to if_ppp.c.
  */
 struct compressor ppp_deflate = {
-    CI_DEFLATE,                        /* compress_proto */
-    z_comp_alloc,              /* comp_alloc */
-    z_comp_free,               /* comp_free */
-    z_comp_init,               /* comp_init */
-    z_comp_reset,              /* comp_reset */
-    z_compress,                        /* compress */
-    z_comp_stats,              /* comp_stat */
-    z_decomp_alloc,            /* decomp_alloc */
-    z_decomp_free,             /* decomp_free */
-    z_decomp_init,             /* decomp_init */
-    z_decomp_reset,            /* decomp_reset */
-    z_decompress,              /* decompress */
-    z_incomp,                  /* incomp */
-    z_comp_stats,              /* decomp_stat */
+       CI_DEFLATE,             /* compress_proto */
+       z_comp_alloc,           /* comp_alloc */
+       z_comp_free,            /* comp_free */
+       z_comp_init,            /* comp_init */
+       z_comp_reset,           /* comp_reset */
+       z_compress,             /* compress */
+       z_comp_stats,           /* comp_stat */
+       z_decomp_alloc,         /* decomp_alloc */
+       z_decomp_free,          /* decomp_free */
+       z_decomp_init,          /* decomp_init */
+       z_decomp_reset,         /* decomp_reset */
+       z_decompress,           /* decompress */
+       z_incomp,               /* incomp */
+       z_comp_stats,           /* decomp_stat */
+};
+
+struct compressor ppp_deflate_draft = {
+       CI_DEFLATE_DRAFT,       /* compress_proto */
+       z_comp_alloc,           /* comp_alloc */
+       z_comp_free,            /* comp_free */
+       z_comp_init,            /* comp_init */
+       z_comp_reset,           /* comp_reset */
+       z_compress,             /* compress */
+       z_comp_stats,           /* comp_stat */
+       z_decomp_alloc,         /* decomp_alloc */
+       z_decomp_free,          /* decomp_free */
+       z_decomp_init,          /* decomp_init */
+       z_decomp_reset,         /* decomp_reset */
+       z_decompress,           /* decompress */
+       z_incomp,               /* incomp */
+       z_comp_stats,           /* decomp_stat */
 };
 
 #ifdef MODULE
@@ -649,6 +678,7 @@ init_module(void)
         if (answer == 0)
                 printk (KERN_INFO
                        "PPP Deflate Compression module registered\n");
+       ppp_register_compressor(&ppp_deflate_draft);
         return answer;
 }
      
@@ -658,7 +688,9 @@ cleanup_module(void)
        if (MOD_IN_USE)
                printk (KERN_INFO
                        "Deflate Compression module busy, remove delayed\n");
-       else
+       else {
                ppp_unregister_compressor (&ppp_deflate);
+               ppp_unregister_compressor (&ppp_deflate_draft);
+       }
 }
 #endif