2001-01-31 Mike Siers <mikes@poliac.com>

	* Nice Update of PPPD support which eliminates the
	requiremetn that drivers be in the termios TASK_DRIVEN mode.
	Mike did significant testing and reports that it seems to be
	more stable and handle larger packets better.  This patch
	replaces the termios tasks with more general pppd network
	driver tasks.  The functions pppinput() and pppstart() get
	called from the interrupt service routine.
	* Makefile.am, configure.ac, net/Makefile.am, net/bpf.h,
	net/ethernet.h, net/if.c, net/if.h, net/if_arp.h, net/if_dl.h,
	net/if_ethersubr.c, net/if_llc.h, net/if_loop.c, net/if_ppp.h,
	net/if_pppvar.h, net/if_types.h, net/netisr.h, net/ppp-comp.h,
	net/ppp_defs.h, net/pppcompress.h, net/radix.c, net/radix.h,
	net/raw_cb.c, net/raw_cb.h, net/raw_usrreq.c, net/route.c,
	net/route.h, net/rtsock.c, pppd/Makefile.am, pppd/README,
	pppd/STATUS, pppd/auth.c, pppd/cbcp.c, pppd/ccp.c, pppd/ccp.h,
	pppd/chap.c, pppd/chap.h, pppd/chap_ms.c, pppd/chap_ms.h,
	pppd/chat.c, pppd/demand.c, pppd/fsm.c, pppd/fsm.h, pppd/ipcp.c,
	pppd/ipcp.h, pppd/ipxcp.c, pppd/ipxcp.h, pppd/lcp.c, pppd/lcp.h,
	pppd/magic.c, pppd/magic.h, pppd/options.c, pppd/patchlevel.h,
	pppd/pathnames.h, pppd/pppd.8, pppd/pppd.h, pppd/rtemsmain.c,
	pppd/rtemspppd.c, pppd/rtemspppd.h, pppd/sys-rtems.c, pppd/upap.c,
	pppd/upap.h, pppd/utils.c, pppd/example/README,
	pppd/example/netconfig.h, wrapup/Makefile.am: Modified.
	* net/bsd-comp.c, net/if_ppp.c, net/ppp-deflate.c, net/ppp.h,
	net/ppp_tty.c, net/pppcompress.c, net/zlib.c, net/zlib.h: New file.
	* modem/, modem/.cvsignore, modem/Makefile.am, modem/ppp.c,
	modem/ppp.h, modem/ppp_tty.c, modem/pppcompress.c: Subdirectory removed.

1 files changed, 683 insertions, 0 deletions

diff --git a/c/src/libnetworking/net/ppp-deflate.c b/c/src/libnetworking/net/ppp-deflate.c
new file mode 100644
index 0000000000..2023735b8b
--- /dev/null
+++ b/c/src/libnetworking/net/ppp-deflate.c
@@ -0,0 +1,683 @@
+/*	$Id$	*/
+
+/*
+ * 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 mbufs on BSD-derived systems.
+ *
+ * Copyright (c) 1994 The Australian National University.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation is hereby granted, provided that the above copyright
+ * notice appears in all copies.  This software is provided without any
+ * warranty, express or implied. The Australian National University
+ * makes no representations about the suitability of this software for
+ * any purpose.
+ *
+ * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
+ * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
+ * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
+ * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
+ * OR MODIFICATIONS.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/systm.h>
+#include <sys/mbuf.h>
+#include <net/ppp_defs.h>
+#include <net/zlib.h>
+
+#define PACKETPTR	struct mbuf *
+#include <net/ppp-comp.h>
+
+#if DO_DEFLATE
+
+#define DEFLATE_DEBUG	1
+
+/*
+ * State for a Deflate (de)compressor.
+ */
+struct deflate_state {
+    int		seqno;
+    int		w_size;
+    int		unit;
+    int		hdrlen;
+    int		mru;
+    int		debug;
+    z_stream	strm;
+    struct compstat stats;
+};
+
+#define DEFLATE_OVHD	2		/* Deflate overhead/packet */
+
+static void	*zalloc __P((void *, u_int items, u_int size));
+static void	zfree __P((void *, void *ptr));
+static void	*z_comp_alloc __P((u_char *options, int opt_len));
+static void	*z_decomp_alloc __P((u_char *options, int opt_len));
+static void	z_comp_free __P((void *state));
+static void	z_decomp_free __P((void *state));
+static int	z_comp_init __P((void *state, u_char *options, int opt_len,
+				 int unit, int hdrlen, int debug));
+static int	z_decomp_init __P((void *state, u_char *options, int opt_len,
+				     int unit, int hdrlen, int mru, int debug));
+static int	z_compress __P((void *state, struct mbuf **mret,
+				  struct mbuf *mp, int slen, int maxolen));
+static void	z_incomp __P((void *state, struct mbuf *dmsg));
+static int	z_decompress __P((void *state, struct mbuf *cmp,
+				    struct mbuf **dmpp));
+static void	z_comp_reset __P((void *state));
+static void	z_decomp_reset __P((void *state));
+static void	z_comp_stats __P((void *state, struct compstat *stats));
+
+/*
+ * 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 */
+};
+
+struct compressor ppp_deflate = {
+    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 */
+};
+
+/*
+ * Space allocation and freeing routines for use by zlib routines.
+ */
+void *
+zalloc(notused, items, size)
+    void *notused;
+    u_int items, size;
+{
+    void *ptr;
+
+    MALLOC(ptr, void *, items * size, M_DEVBUF, M_NOWAIT);
+    return ptr;
+}
+
+void
+zfree(notused, ptr)
+    void *notused;
+    void *ptr;
+{
+    FREE(ptr, M_DEVBUF);
+}
+
+/*
+ * Allocate space for a compressor.
+ */
+static void *
+z_comp_alloc(options, opt_len)
+    u_char *options;
+    int opt_len;
+{
+    struct 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;
+
+    MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
+	   M_DEVBUF, M_NOWAIT);
+    if (state == NULL)
+	return NULL;
+
+    state->strm.next_in = NULL;
+    state->strm.zalloc = zalloc;
+    state->strm.zfree = zfree;
+    if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
+		     -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
+	FREE(state, M_DEVBUF);
+	return NULL;
+    }
+
+    state->w_size = w_size;
+    bzero(&state->stats, sizeof(state->stats));
+    return (void *) state;
+}
+
+static void
+z_comp_free(arg)
+    void *arg;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    deflateEnd(&state->strm);
+    FREE(state, M_DEVBUF);
+}
+
+static int
+z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
+    void *arg;
+    u_char *options;
+    int opt_len, unit, hdrlen, debug;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    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->hdrlen = hdrlen;
+    state->debug = debug;
+
+    deflateReset(&state->strm);
+
+    return 1;
+}
+
+static void
+z_comp_reset(arg)
+    void *arg;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    state->seqno = 0;
+    deflateReset(&state->strm);
+}
+
+int
+z_compress(arg, mret, mp, orig_len, maxolen)
+    void *arg;
+    struct mbuf **mret;		/* compressed packet (out) */
+    struct mbuf *mp;		/* uncompressed packet (in) */
+    int orig_len, maxolen;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+    u_char *rptr, *wptr;
+    int proto, olen, wspace, r, flush;
+    struct mbuf *m;
+
+    /*
+     * Check that the protocol is in the range we handle.
+     */
+    rptr = mtod(mp, u_char *);
+    proto = PPP_PROTOCOL(rptr);
+    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
+	*mret = NULL;
+	return orig_len;
+    }
+
+    /* Allocate one mbuf initially. */
+    if (maxolen > orig_len)
+	maxolen = orig_len;
+    MGET(m, M_DONTWAIT, MT_DATA);
+    *mret = m;
+    if (m != NULL) {
+	m->m_len = 0;
+	if (maxolen + state->hdrlen > MLEN)
+	    MCLGET(m, M_DONTWAIT);
+	wspace = M_TRAILINGSPACE(m);
+	if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
+	    m->m_data += state->hdrlen;
+	    wspace -= state->hdrlen;
+	}
+	wptr = mtod(m, u_char *);
+
+	/*
+	 * 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 = wspace - (PPP_HDRLEN + 2);
+    } else {
+	state->strm.next_out = NULL;
+	state->strm.avail_out = 1000000;
+	wptr = NULL;
+	wspace = 0;
+    }
+    ++state->seqno;
+
+    rptr += (proto > 0xff)? 2: 3;	/* skip 1st proto byte if 0 */
+    state->strm.next_in = rptr;
+    state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
+    mp = mp->m_next;
+    flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
+    olen = 0;
+    for (;;) {
+	r = deflate(&state->strm, flush);
+	if (r != Z_OK) {
+	    printf("z_compress: deflate returned %d (%s)\n",
+		   r, (state->strm.msg? state->strm.msg: ""));
+	    break;
+	}
+	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
+	    break;		/* all done */
+	if (state->strm.avail_in == 0 && mp != NULL) {
+	    state->strm.next_in = mtod(mp, u_char *);
+	    state->strm.avail_in = mp->m_len;
+	    mp = mp->m_next;
+	    if (mp == NULL)
+		flush = Z_PACKET_FLUSH;
+	}
+	if (state->strm.avail_out == 0) {
+	    if (m != NULL) {
+		m->m_len = wspace;
+		olen += wspace;
+		MGET(m->m_next, M_DONTWAIT, MT_DATA);
+		m = m->m_next;
+		if (m != NULL) {
+		    m->m_len = 0;
+		    if (maxolen - olen > MLEN)
+			MCLGET(m, M_DONTWAIT);
+		    state->strm.next_out = mtod(m, u_char *);
+		    state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
+		}
+	    }
+	    if (m == NULL) {
+		state->strm.next_out = NULL;
+		state->strm.avail_out = 1000000;
+	    }
+	}
+    }
+    if (m != NULL)
+	olen += (m->m_len = wspace - 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 (m != NULL && olen < orig_len
+	&& !(olen == PPP_HDRLEN + 3 && *wptr == 0)) {
+	state->stats.comp_bytes += olen;
+	state->stats.comp_packets++;
+    } else {
+	if (*mret != NULL) {
+	    m_freem(*mret);
+	    *mret = NULL;
+	}
+	state->stats.inc_bytes += orig_len;
+	state->stats.inc_packets++;
+	olen = orig_len;
+    }
+    state->stats.unc_bytes += orig_len;
+    state->stats.unc_packets++;
+
+    return olen;
+}
+
+static void
+z_comp_stats(arg, stats)
+    void *arg;
+    struct compstat *stats;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+    u_int out;
+
+    *stats = state->stats;
+    stats->ratio = stats->unc_bytes;
+    out = stats->comp_bytes + stats->inc_bytes;
+    if (stats->ratio <= 0x7ffffff)
+	stats->ratio <<= 8;
+    else
+	out >>= 8;
+    if (out != 0)
+	stats->ratio /= out;
+}
+
+/*
+ * Allocate space for a decompressor.
+ */
+static void *
+z_decomp_alloc(options, opt_len)
+    u_char *options;
+    int opt_len;
+{
+    struct 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;
+
+    MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
+	   M_DEVBUF, M_NOWAIT);
+    if (state == NULL)
+	return NULL;
+
+    state->strm.next_out = NULL;
+    state->strm.zalloc = zalloc;
+    state->strm.zfree = zfree;
+    if (inflateInit2(&state->strm, -w_size) != Z_OK) {
+	FREE(state, M_DEVBUF);
+	return NULL;
+    }
+
+    state->w_size = w_size;
+    bzero(&state->stats, sizeof(state->stats));
+    return (void *) state;
+}
+
+static void
+z_decomp_free(arg)
+    void *arg;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    inflateEnd(&state->strm);
+    FREE(state, M_DEVBUF);
+}
+
+static int
+z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
+    void *arg;
+    u_char *options;
+    int opt_len, unit, hdrlen, mru, debug;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    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->hdrlen = hdrlen;
+    state->debug = debug;
+    state->mru = mru;
+
+    inflateReset(&state->strm);
+
+    return 1;
+}
+
+static void
+z_decomp_reset(arg)
+    void *arg;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+
+    state->seqno = 0;
+    inflateReset(&state->strm);
+}
+
+/*
+ * Decompress a Deflate-compressed packet.
+ *
+ * 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
+z_decompress(arg, mi, mop)
+    void *arg;
+    struct mbuf *mi, **mop;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+    struct mbuf *mo, *mo_head;
+    u_char *rptr, *wptr;
+    int rlen, olen, ospace;
+    int seq, i, flush, r, decode_proto;
+    u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
+
+    *mop = NULL;
+    rptr = mtod(mi, u_char *);
+    rlen = mi->m_len;
+    for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
+	while (rlen <= 0) {
+	    mi = mi->m_next;
+	    if (mi == NULL)
+		return DECOMP_ERROR;
+	    rptr = mtod(mi, u_char *);
+	    rlen = mi->m_len;
+	}
+	hdr[i] = *rptr++;
+	--rlen;
+    }
+
+    /* Check the sequence number. */
+    seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
+    if (seq != state->seqno) {
+	if (state->debug)
+	    printf("z_decompress%d: bad seq # %d, expected %d\n",
+		   state->unit, seq, state->seqno);
+	return DECOMP_ERROR;
+    }
+    ++state->seqno;
+
+    /* Allocate an output mbuf. */
+    MGETHDR(mo, M_DONTWAIT, MT_DATA);
+    if (mo == NULL)
+	return DECOMP_ERROR;
+    mo_head = mo;
+    mo->m_len = 0;
+    mo->m_next = NULL;
+    MCLGET(mo, M_DONTWAIT);
+    ospace = M_TRAILINGSPACE(mo);
+    if (state->hdrlen + PPP_HDRLEN < ospace) {
+	mo->m_data += state->hdrlen;
+	ospace -= state->hdrlen;
+    }
+
+    /*
+     * Fill in the first part of the PPP header.  The protocol field
+     * comes from the decompressed data.
+     */
+    wptr = mtod(mo, u_char *);
+    wptr[0] = PPP_ADDRESS(hdr);
+    wptr[1] = PPP_CONTROL(hdr);
+    wptr[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 = rptr;
+    state->strm.avail_in = rlen;
+    mi = mi->m_next;
+    flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
+    rlen += PPP_HDRLEN + DEFLATE_OVHD;
+    state->strm.next_out = wptr + 3;
+    state->strm.avail_out = 1;
+    decode_proto = 1;
+    olen = PPP_HDRLEN;
+
+    /*
+     * Call inflate, supplying more input or output as needed.
+     */
+    for (;;) {
+	r = inflate(&state->strm, flush);
+	if (r != Z_OK) {
+#if !DEFLATE_DEBUG
+	    if (state->debug)
+#endif
+		printf("z_decompress%d: inflate returned %d (%s)\n",
+		       state->unit, r, (state->strm.msg? state->strm.msg: ""));
+	    m_freem(mo_head);
+	    return DECOMP_FATALERROR;
+	}
+	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
+	    break;		/* all done */
+	if (state->strm.avail_in == 0 && mi != NULL) {
+	    state->strm.next_in = mtod(mi, u_char *);
+	    state->strm.avail_in = mi->m_len;
+	    rlen += mi->m_len;
+	    mi = mi->m_next;
+	    if (mi == NULL)
+		flush = Z_PACKET_FLUSH;
+	}
+	if (state->strm.avail_out == 0) {
+	    if (decode_proto) {
+		state->strm.avail_out = ospace - PPP_HDRLEN;
+		if ((wptr[3] & 1) == 0) {
+		    /* 2-byte protocol field */
+		    wptr[2] = wptr[3];
+		    --state->strm.next_out;
+		    ++state->strm.avail_out;
+		    --olen;
+		}
+		decode_proto = 0;
+	    } else {
+		mo->m_len = ospace;
+		olen += ospace;
+		MGET(mo->m_next, M_DONTWAIT, MT_DATA);
+		mo = mo->m_next;
+		if (mo == NULL) {
+		    m_freem(mo_head);
+		    return DECOMP_ERROR;
+		}
+		MCLGET(mo, M_DONTWAIT);
+		state->strm.next_out = mtod(mo, u_char *);
+		state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
+	    }
+	}
+    }
+    if (decode_proto) {
+	m_freem(mo_head);
+	return DECOMP_ERROR;
+    }
+    olen += (mo->m_len = ospace - state->strm.avail_out);
+#if DEFLATE_DEBUG
+    if (olen > state->mru + PPP_HDRLEN)
+	printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
+	       state->unit, olen, state->mru + PPP_HDRLEN);
+#endif
+
+    state->stats.unc_bytes += olen;
+    state->stats.unc_packets++;
+    state->stats.comp_bytes += rlen;
+    state->stats.comp_packets++;
+
+    *mop = mo_head;
+    return DECOMP_OK;
+}
+
+/*
+ * Incompressible data has arrived - add it to the history.
+ */
+static void
+z_incomp(arg, mi)
+    void *arg;
+    struct mbuf *mi;
+{
+    struct deflate_state *state = (struct deflate_state *) arg;
+    u_char *rptr;
+    int rlen, proto, r;
+
+    /*
+     * Check that the protocol is one we handle.
+     */
+    rptr = mtod(mi, u_char *);
+    proto = PPP_PROTOCOL(rptr);
+    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+	return;
+
+    ++state->seqno;
+
+    /*
+     * Iterate through the mbufs, adding the characters in them
+     * to the decompressor's history.  For the first mbuf, we start
+     * at the either the 1st or 2nd byte of the protocol field,
+     * depending on whether the protocol value is compressible.
+     */
+    rlen = mi->m_len;
+    state->strm.next_in = rptr + 3;
+    state->strm.avail_in = rlen - 3;
+    if (proto > 0xff) {
+	--state->strm.next_in;
+	++state->strm.avail_in;
+    }
+    for (;;) {
+	r = inflateIncomp(&state->strm);
+	if (r != Z_OK) {
+	    /* gak! */
+#if !DEFLATE_DEBUG
+	    if (state->debug)
+#endif
+		printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
+		       state->unit, r, (state->strm.msg? state->strm.msg: ""));
+	    return;
+	}
+	mi = mi->m_next;
+	if (mi == NULL)
+	    break;
+	state->strm.next_in = mtod(mi, u_char *);
+	state->strm.avail_in = mi->m_len;
+	rlen += mi->m_len;
+    }
+
+    /*
+     * Update stats.
+     */
+    state->stats.inc_bytes += rlen;
+    state->stats.inc_packets++;
+    state->stats.unc_bytes += rlen;
+    state->stats.unc_packets++;
+}
+
+#endif /* DO_DEFLATE */