]> git.ozlabs.org Git - ppp.git/blobdiff - solaris/ppp_comp.c
1) Created a subdirectory called 'solaris'. Currently it contains a replica
[ppp.git] / solaris / ppp_comp.c
diff --git a/solaris/ppp_comp.c b/solaris/ppp_comp.c
new file mode 100644 (file)
index 0000000..8177b83
--- /dev/null
@@ -0,0 +1,1126 @@
+/*
+ * ppp_comp.c - STREAMS module for kernel-level compression and CCP support.
+ *
+ * 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.
+ *
+ * $Id: ppp_comp.c,v 1.1 2000/04/18 23:51:28 masputra Exp $
+ */
+
+/*
+ * This file is used under SVR4, Solaris 2, SunOS 4, and Digital UNIX.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/stream.h>
+
+#ifdef SVR4
+#include <sys/conf.h>
+#include <sys/cmn_err.h>
+#include <sys/ddi.h>
+#else
+#include <sys/user.h>
+#ifdef __osf__
+#include <sys/cmn_err.h>
+#endif
+#endif /* SVR4 */
+
+#include <net/ppp_defs.h>
+#include <net/pppio.h>
+#include "ppp_mod.h"
+
+#ifdef __osf__
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#endif
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <net/vjcompress.h>
+
+#define PACKETPTR      mblk_t *
+#include <net/ppp-comp.h>
+
+MOD_OPEN_DECL(ppp_comp_open);
+MOD_CLOSE_DECL(ppp_comp_close);
+static int ppp_comp_rput __P((queue_t *, mblk_t *));
+static int ppp_comp_rsrv __P((queue_t *));
+static int ppp_comp_wput __P((queue_t *, mblk_t *));
+static int ppp_comp_wsrv __P((queue_t *));
+static void ppp_comp_ccp __P((queue_t *, mblk_t *, int));
+static int msg_byte __P((mblk_t *, unsigned int));
+
+/* Extract byte i of message mp. */
+#define MSG_BYTE(mp, i)        ((i) < (mp)->b_wptr - (mp)->b_rptr? (mp)->b_rptr[i]: \
+                        msg_byte((mp), (i)))
+
+/* Is this LCP packet one we have to transmit using LCP defaults? */
+#define LCP_USE_DFLT(mp)       (1 <= (code = MSG_BYTE((mp), 4)) && code <= 7)
+
+#define PPP_COMP_ID 0xbadf
+static struct module_info minfo = {
+#ifdef PRIOQ
+    PPP_COMP_ID, "ppp_comp", 0, INFPSZ, 16512, 16384,
+#else
+    PPP_COMP_ID, "ppp_comp", 0, INFPSZ, 16384, 4096,
+#endif
+};
+
+static struct qinit r_init = {
+    ppp_comp_rput, ppp_comp_rsrv, ppp_comp_open, ppp_comp_close,
+    NULL, &minfo, NULL
+};
+
+static struct qinit w_init = {
+    ppp_comp_wput, ppp_comp_wsrv, NULL, NULL, NULL, &minfo, NULL
+};
+
+#if defined(SVR4) && !defined(SOL2)
+int pcmpdevflag = 0;
+#define ppp_compinfo pcmpinfo
+#endif
+struct streamtab ppp_compinfo = {
+    &r_init, &w_init, NULL, NULL
+};
+
+int ppp_comp_count;            /* number of module instances in use */
+
+#ifdef __osf__
+
+static void ppp_comp_alloc __P((comp_state_t *));
+typedef struct memreq {
+    unsigned char comp_opts[20];
+    int cmd;
+    int thread_status;
+    char *returned_mem;
+} memreq_t;
+
+#endif
+
+typedef struct comp_state {
+    int                flags;
+    int                mru;
+    int                mtu;
+    int                unit;
+    struct compressor *xcomp;
+    void       *xstate;
+    struct compressor *rcomp;
+    void       *rstate;
+    struct vjcompress vj_comp;
+    int                vj_last_ierrors;
+    struct pppstat stats;
+#ifdef __osf__
+    memreq_t   memreq;
+    thread_t   thread;
+#endif
+} comp_state_t;
+
+
+#ifdef __osf__
+extern task_t first_task;
+#endif
+
+/* Bits in flags are as defined in pppio.h. */
+#define CCP_ERR                (CCP_ERROR | CCP_FATALERROR)
+#define LAST_MOD       0x1000000       /* no ppp modules below us */
+#define DBGLOG         0x2000000       /* log debugging stuff */
+
+#define MAX_IPHDR      128     /* max TCP/IP header size */
+#define MAX_VJHDR      20      /* max VJ compressed header size (?) */
+
+#undef MIN             /* just in case */
+#define MIN(a, b)      ((a) < (b)? (a): (b))
+
+/*
+ * List of compressors we know about.
+ */
+
+#if DO_BSD_COMPRESS
+extern struct compressor ppp_bsd_compress;
+#endif
+#if DO_DEFLATE
+extern struct compressor ppp_deflate, ppp_deflate_draft;
+#endif
+
+struct compressor *ppp_compressors[] = {
+#if DO_BSD_COMPRESS
+    &ppp_bsd_compress,
+#endif
+#if DO_DEFLATE
+    &ppp_deflate,
+    &ppp_deflate_draft,
+#endif
+    NULL
+};
+
+/*
+ * STREAMS module entry points.
+ */
+MOD_OPEN(ppp_comp_open)
+{
+    comp_state_t *cp;
+#ifdef __osf__
+    thread_t thread;
+#endif
+
+    if (q->q_ptr == NULL) {
+       cp = (comp_state_t *) ALLOC_SLEEP(sizeof(comp_state_t));
+       if (cp == NULL)
+           OPEN_ERROR(ENOSR);
+       bzero((caddr_t)cp, sizeof(comp_state_t));
+       WR(q)->q_ptr = q->q_ptr = (caddr_t) cp;
+       cp->mru = PPP_MRU;
+       cp->mtu = PPP_MTU;
+       cp->xstate = NULL;
+       cp->rstate = NULL;
+       vj_compress_init(&cp->vj_comp, -1);
+#ifdef __osf__
+       if (!(thread = kernel_thread_w_arg(first_task, ppp_comp_alloc, (void *)cp)))
+               OPEN_ERROR(ENOSR);
+       cp->thread = thread;
+#endif
+       ++ppp_comp_count;
+       qprocson(q);
+    }
+    return 0;
+}
+
+MOD_CLOSE(ppp_comp_close)
+{
+    comp_state_t *cp;
+
+    qprocsoff(q);
+    cp = (comp_state_t *) q->q_ptr;
+    if (cp != NULL) {
+       if (cp->xstate != NULL)
+           (*cp->xcomp->comp_free)(cp->xstate);
+       if (cp->rstate != NULL)
+           (*cp->rcomp->decomp_free)(cp->rstate);
+#ifdef __osf__
+       if (!cp->thread)
+           printf("ppp_comp_close: NULL thread!\n");
+       else
+           thread_terminate(cp->thread);
+#endif
+       FREE(cp, sizeof(comp_state_t));
+       q->q_ptr = NULL;
+       OTHERQ(q)->q_ptr = NULL;
+       --ppp_comp_count;
+    }
+    return 0;
+}
+
+#ifdef __osf__
+
+/* thread for calling back to a compressor's memory allocator
+ * Needed for Digital UNIX since it's VM can't handle requests
+ * for large amounts of memory without blocking.  The thread
+ * provides a context in which we can call a memory allocator
+ * that may block.
+ */
+static void
+ppp_comp_alloc(comp_state_t *cp)
+{
+    int len, cmd;
+    unsigned char *compressor_options;
+    thread_t thread;
+    void *(*comp_allocator)();
+
+
+#if defined(MAJOR_VERSION) && (MAJOR_VERSION <= 2)
+
+    /* In 2.x and earlier the argument gets passed
+     * in the thread structure itself.  Yuck.
+     */
+    thread = current_thread();
+    cp = thread->reply_port;
+    thread->reply_port = PORT_NULL;
+
+#endif
+
+    for (;;) {
+       assert_wait((vm_offset_t)&cp->memreq.thread_status, TRUE);
+       thread_block();
+
+       if (thread_should_halt(current_thread()))
+           thread_halt_self();
+       cmd = cp->memreq.cmd;
+       compressor_options = &cp->memreq.comp_opts[0];
+       len = compressor_options[1];
+       if (cmd == PPPIO_XCOMP) {
+           cp->memreq.returned_mem = cp->xcomp->comp_alloc(compressor_options, len);
+           if (!cp->memreq.returned_mem) {
+               cp->memreq.thread_status = ENOSR;
+           } else {
+               cp->memreq.thread_status = 0;
+           }
+       } else {
+           cp->memreq.returned_mem = cp->rcomp->decomp_alloc(compressor_options, len);
+           if (!cp->memreq.returned_mem) {
+               cp->memreq.thread_status = ENOSR;
+           } else {
+               cp->memreq.thread_status = 0;
+           }
+       }
+    }
+}
+
+#endif /* __osf__ */
+
+/* here's the deal with memory allocation under Digital UNIX.
+ * Some other may also benefit from this...
+ * We can't ask for huge chunks of memory in a context where
+ * the caller can't be put to sleep (like, here.)  The alloc
+ * is likely to fail.  Instead we do this: the first time we
+ * get called, kick off a thread to do the allocation.  Return
+ * immediately to the caller with EAGAIN, as an indication that
+ * they should send down the ioctl again.  By the time the
+ * second call comes in it's likely that the memory allocation
+ * thread will have returned with the requested memory.  We will
+ * continue to return EAGAIN however until the thread has completed.
+ * When it has, we return zero (and the memory) if the allocator
+ * was successful and ENOSR otherwise.
+ *
+ * Callers of the RCOMP and XCOMP ioctls are encouraged (but not
+ * required) to loop for some number of iterations with a small
+ * delay in the loop body (for instance a 1/10-th second "sleep"
+ * via select.)
+ */
+static int
+ppp_comp_wput(q, mp)
+    queue_t *q;
+    mblk_t *mp;
+{
+    struct iocblk *iop;
+    comp_state_t *cp;
+    int error, len, n;
+    int flags, mask;
+    mblk_t *np;
+    struct compressor **comp;
+    struct ppp_stats *psp;
+    struct ppp_comp_stats *csp;
+    unsigned char *opt_data;
+    int nxslots, nrslots;
+
+    cp = (comp_state_t *) q->q_ptr;
+    if (cp == 0) {
+       DPRINT("cp == 0 in ppp_comp_wput\n");
+       freemsg(mp);
+       return 0;
+    }
+
+    switch (mp->b_datap->db_type) {
+
+    case M_DATA:
+       putq(q, mp);
+       break;
+
+    case M_IOCTL:
+       iop = (struct iocblk *) mp->b_rptr;
+       error = EINVAL;
+       switch (iop->ioc_cmd) {
+
+       case PPPIO_CFLAGS:
+           /* set/get CCP state */
+           if (iop->ioc_count != 2 * sizeof(int))
+               break;
+           if (mp->b_cont == 0) {
+               DPRINT1("ppp_comp_wput/%d: PPPIO_CFLAGS b_cont = 0!\n", cp->unit);
+               break;
+           }
+           flags = ((int *) mp->b_cont->b_rptr)[0];
+           mask = ((int *) mp->b_cont->b_rptr)[1];
+           cp->flags = (cp->flags & ~mask) | (flags & mask);
+           if ((mask & CCP_ISOPEN) && (flags & CCP_ISOPEN) == 0) {
+               if (cp->xstate != NULL) {
+                   (*cp->xcomp->comp_free)(cp->xstate);
+                   cp->xstate = NULL;
+               }
+               if (cp->rstate != NULL) {
+                   (*cp->rcomp->decomp_free)(cp->rstate);
+                   cp->rstate = NULL;
+               }
+               cp->flags &= ~CCP_ISUP;
+           }
+           error = 0;
+           iop->ioc_count = sizeof(int);
+           ((int *) mp->b_cont->b_rptr)[0] = cp->flags;
+           mp->b_cont->b_wptr = mp->b_cont->b_rptr + sizeof(int);
+           break;
+
+       case PPPIO_VJINIT:
+           /*
+            * Initialize VJ compressor/decompressor
+            */
+           if (iop->ioc_count != 2)
+               break;
+           if (mp->b_cont == 0) {
+               DPRINT1("ppp_comp_wput/%d: PPPIO_VJINIT b_cont = 0!\n", cp->unit);
+               break;
+           }
+           nxslots = mp->b_cont->b_rptr[0] + 1;
+           nrslots = mp->b_cont->b_rptr[1] + 1;
+           if (nxslots > MAX_STATES || nrslots > MAX_STATES)
+               break;
+           vj_compress_init(&cp->vj_comp, nxslots);
+           cp->vj_last_ierrors = cp->stats.ppp_ierrors;
+           error = 0;
+           iop->ioc_count = 0;
+           break;
+
+       case PPPIO_XCOMP:
+       case PPPIO_RCOMP:
+           if (iop->ioc_count <= 0)
+               break;
+           if (mp->b_cont == 0) {
+               DPRINT1("ppp_comp_wput/%d: PPPIO_[XR]COMP b_cont = 0!\n", cp->unit);
+               break;
+           }
+           opt_data = mp->b_cont->b_rptr;
+           len = mp->b_cont->b_wptr - opt_data;
+           if (len > iop->ioc_count)
+               len = iop->ioc_count;
+           if (opt_data[1] < 2 || opt_data[1] > len)
+               break;
+           for (comp = ppp_compressors; *comp != NULL; ++comp)
+               if ((*comp)->compress_proto == opt_data[0]) {
+                   /* here's the handler! */
+                   error = 0;
+#ifndef __osf__
+                   if (iop->ioc_cmd == PPPIO_XCOMP) {
+                       /* A previous call may have fetched memory for a compressor
+                        * that's now being retired or reset.  Free it using it's
+                        * mechanism for freeing stuff.
+                        */
+                       if (cp->xstate != NULL) {
+                           (*cp->xcomp->comp_free)(cp->xstate);
+                           cp->xstate = NULL;
+                       }
+                       cp->xcomp = *comp;
+                       cp->xstate = (*comp)->comp_alloc(opt_data, len);
+                       if (cp->xstate == NULL)
+                           error = ENOSR;
+                   } else {
+                       if (cp->rstate != NULL) {
+                           (*cp->rcomp->decomp_free)(cp->rstate);
+                           cp->rstate = NULL;
+                       }
+                       cp->rcomp = *comp;
+                       cp->rstate = (*comp)->decomp_alloc(opt_data, len);
+                       if (cp->rstate == NULL)
+                           error = ENOSR;
+                   }
+#else
+                   if ((error = cp->memreq.thread_status) != EAGAIN)
+                   if (iop->ioc_cmd == PPPIO_XCOMP) {
+                       if (cp->xstate) {
+                           (*cp->xcomp->comp_free)(cp->xstate);
+                           cp->xstate = 0;
+                       }
+                       /* sanity check for compressor options
+                        */
+                       if (sizeof (cp->memreq.comp_opts) < len) {
+                           printf("can't handle options for compressor %d (%d)\n", opt_data[0],
+                               opt_data[1]);
+                           cp->memreq.thread_status = ENOSR;
+                           cp->memreq.returned_mem = 0;
+                       }
+                       /* fill in request for the thread and kick it off
+                        */
+                       if (cp->memreq.thread_status == 0 && !cp->memreq.returned_mem) {
+                           bcopy(opt_data, cp->memreq.comp_opts, len);
+                           cp->memreq.cmd = PPPIO_XCOMP;
+                           cp->xcomp = *comp;
+                           error = cp->memreq.thread_status = EAGAIN;
+                           thread_wakeup((vm_offset_t)&cp->memreq.thread_status);
+                       } else {
+                           cp->xstate = cp->memreq.returned_mem;
+                           cp->memreq.returned_mem = 0;
+                           cp->memreq.thread_status = 0;
+                       }
+                   } else {
+                       if (cp->rstate) {
+                           (*cp->rcomp->decomp_free)(cp->rstate);
+                           cp->rstate = NULL;
+                       }
+                       if (sizeof (cp->memreq.comp_opts) < len) {
+                           printf("can't handle options for compressor %d (%d)\n", opt_data[0],
+                               opt_data[1]);
+                           cp->memreq.thread_status = ENOSR;
+                           cp->memreq.returned_mem = 0;
+                       }
+                       if (cp->memreq.thread_status == 0 && !cp->memreq.returned_mem) {
+                           bcopy(opt_data, cp->memreq.comp_opts, len);
+                           cp->memreq.cmd = PPPIO_RCOMP;
+                           cp->rcomp = *comp;
+                           error = cp->memreq.thread_status = EAGAIN;
+                           thread_wakeup((vm_offset_t)&cp->memreq.thread_status);
+                       } else {
+                           cp->rstate = cp->memreq.returned_mem;
+                           cp->memreq.returned_mem = 0;
+                           cp->memreq.thread_status = 0;
+                       }
+                   }
+#endif
+                   break;
+               }
+           iop->ioc_count = 0;
+           break;
+
+       case PPPIO_GETSTAT:
+           if ((cp->flags & LAST_MOD) == 0) {
+               error = -1;     /* let the ppp_ahdl module handle it */
+               break;
+           }
+           np = allocb(sizeof(struct ppp_stats), BPRI_HI);
+           if (np == 0) {
+               error = ENOSR;
+               break;
+           }
+           if (mp->b_cont != 0)
+               freemsg(mp->b_cont);
+           mp->b_cont = np;
+           psp = (struct ppp_stats *) np->b_wptr;
+           np->b_wptr += sizeof(struct ppp_stats);
+           iop->ioc_count = sizeof(struct ppp_stats);
+           psp->p = cp->stats;
+           psp->vj = cp->vj_comp.stats;
+           error = 0;
+           break;
+
+       case PPPIO_GETCSTAT:
+           np = allocb(sizeof(struct ppp_comp_stats), BPRI_HI);
+           if (np == 0) {
+               error = ENOSR;
+               break;
+           }
+           if (mp->b_cont != 0)
+               freemsg(mp->b_cont);
+           mp->b_cont = np;
+           csp = (struct ppp_comp_stats *) np->b_wptr;
+           np->b_wptr += sizeof(struct ppp_comp_stats);
+           iop->ioc_count = sizeof(struct ppp_comp_stats);
+           bzero((caddr_t)csp, sizeof(struct ppp_comp_stats));
+           if (cp->xstate != 0)
+               (*cp->xcomp->comp_stat)(cp->xstate, &csp->c);
+           if (cp->rstate != 0)
+               (*cp->rcomp->decomp_stat)(cp->rstate, &csp->d);
+           error = 0;
+           break;
+
+       case PPPIO_DEBUG:
+           if (iop->ioc_count != sizeof(int))
+               break;
+           if (mp->b_cont == 0) {
+               DPRINT1("ppp_comp_wput/%d: PPPIO_DEBUG b_cont = 0!\n", cp->unit);
+               break;
+           }
+           n = *(int *)mp->b_cont->b_rptr;
+           if (n == PPPDBG_LOG + PPPDBG_COMP) {
+               DPRINT1("ppp_comp%d: debug log enabled\n", cp->unit);
+               cp->flags |= DBGLOG;
+               error = 0;
+               iop->ioc_count = 0;
+           } else {
+               error = -1;
+           }
+           break;
+
+       case PPPIO_LASTMOD:
+           cp->flags |= LAST_MOD;
+           error = 0;
+           break;
+
+       default:
+           error = -1;
+           break;
+       }
+
+       if (error < 0)
+           putnext(q, mp);
+       else if (error == 0) {
+           mp->b_datap->db_type = M_IOCACK;
+           qreply(q, mp);
+       } else {
+           mp->b_datap->db_type = M_IOCNAK;
+           iop->ioc_error = error;
+           iop->ioc_count = 0;
+           qreply(q, mp);
+       }
+       break;
+
+    case M_CTL:
+       switch (*mp->b_rptr) {
+       case PPPCTL_MTU:
+           cp->mtu = ((unsigned short *)mp->b_rptr)[1];
+           break;
+       case PPPCTL_MRU:
+           cp->mru = ((unsigned short *)mp->b_rptr)[1];
+           break;
+       case PPPCTL_UNIT:
+           cp->unit = mp->b_rptr[1];
+           break;
+       }
+       putnext(q, mp);
+       break;
+
+    default:
+       putnext(q, mp);
+    }
+
+    return 0;
+}
+
+static int
+ppp_comp_wsrv(q)
+    queue_t *q;
+{
+    mblk_t *mp, *cmp = NULL;
+    comp_state_t *cp;
+    int len, proto, type, hlen, code;
+    struct ip *ip;
+    unsigned char *vjhdr, *dp;
+
+    cp = (comp_state_t *) q->q_ptr;
+    if (cp == 0) {
+       DPRINT("cp == 0 in ppp_comp_wsrv\n");
+       return 0;
+    }
+
+    while ((mp = getq(q)) != 0) {
+       /* assert(mp->b_datap->db_type == M_DATA) */
+#ifdef PRIOQ
+        if (!bcanputnext(q,mp->b_band))
+#else
+        if (!canputnext(q))
+#endif PRIOQ
+       {
+           putbq(q, mp);
+           break;
+       }
+
+       /*
+        * First check the packet length and work out what the protocol is.
+        */
+       len = msgdsize(mp);
+       if (len < PPP_HDRLEN) {
+           DPRINT1("ppp_comp_wsrv: bogus short packet (%d)\n", len);
+           freemsg(mp);
+           cp->stats.ppp_oerrors++;
+           putctl1(RD(q)->q_next, M_CTL, PPPCTL_OERROR);
+           continue;
+       }
+       proto = (MSG_BYTE(mp, 2) << 8) + MSG_BYTE(mp, 3);
+
+       /*
+        * Make sure we've got enough data in the first mblk
+        * and that we are its only user.
+        */
+       if (proto == PPP_CCP)
+           hlen = len;
+       else if (proto == PPP_IP)
+           hlen = PPP_HDRLEN + MAX_IPHDR;
+       else
+           hlen = PPP_HDRLEN;
+       if (hlen > len)
+           hlen = len;
+       if (mp->b_wptr < mp->b_rptr + hlen || mp->b_datap->db_ref > 1) {
+           PULLUP(mp, hlen);
+           if (mp == 0) {
+               DPRINT1("ppp_comp_wsrv: pullup failed (%d)\n", hlen);
+               cp->stats.ppp_oerrors++;
+               putctl1(RD(q)->q_next, M_CTL, PPPCTL_OERROR);
+               continue;
+           }
+       }
+
+       /*
+        * Do VJ compression if requested.
+        */
+       if (proto == PPP_IP && (cp->flags & COMP_VJC)) {
+           ip = (struct ip *) (mp->b_rptr + PPP_HDRLEN);
+           if (ip->ip_p == IPPROTO_TCP) {
+               type = vj_compress_tcp(ip, len - PPP_HDRLEN, &cp->vj_comp,
+                                      (cp->flags & COMP_VJCCID), &vjhdr);
+               switch (type) {
+               case TYPE_UNCOMPRESSED_TCP:
+                   mp->b_rptr[3] = proto = PPP_VJC_UNCOMP;
+                   break;
+               case TYPE_COMPRESSED_TCP:
+                   dp = vjhdr - PPP_HDRLEN;
+                   dp[1] = mp->b_rptr[1]; /* copy control field */
+                   dp[0] = mp->b_rptr[0]; /* copy address field */
+                   dp[2] = 0;             /* set protocol field */
+                   dp[3] = proto = PPP_VJC_COMP;
+                   mp->b_rptr = dp;
+                   break;
+               }
+           }
+       }
+
+       /*
+        * Do packet compression if enabled.
+        */
+       if (proto == PPP_CCP)
+           ppp_comp_ccp(q, mp, 0);
+       else if (proto != PPP_LCP && (cp->flags & CCP_COMP_RUN)
+                && cp->xstate != NULL) {
+           len = msgdsize(mp);
+           (*cp->xcomp->compress)(cp->xstate, &cmp, mp, len,
+                       (cp->flags & CCP_ISUP? cp->mtu + PPP_HDRLEN: 0));
+           if (cmp != NULL) {
+#ifdef PRIOQ
+               cmp->b_band=mp->b_band;
+#endif PRIOQ
+               freemsg(mp);
+               mp = cmp;
+           }
+       }
+
+       /*
+        * Do address/control and protocol compression if enabled.
+        */
+       if ((cp->flags & COMP_AC)
+           && !(proto == PPP_LCP && LCP_USE_DFLT(mp))) {
+           mp->b_rptr += 2;    /* drop the address & ctrl fields */
+           if (proto < 0x100 && (cp->flags & COMP_PROT))
+               ++mp->b_rptr;   /* drop the high protocol byte */
+       } else if (proto < 0x100 && (cp->flags & COMP_PROT)) {
+           /* shuffle up the address & ctrl fields */
+           mp->b_rptr[2] = mp->b_rptr[1];
+           mp->b_rptr[1] = mp->b_rptr[0];
+           ++mp->b_rptr;
+       }
+
+       cp->stats.ppp_opackets++;
+       cp->stats.ppp_obytes += msgdsize(mp);
+       putnext(q, mp);
+    }
+
+    return 0;
+}
+
+static int
+ppp_comp_rput(q, mp)
+    queue_t *q;
+    mblk_t *mp;
+{
+    comp_state_t *cp;
+    struct iocblk *iop;
+    struct ppp_stats *psp;
+
+    cp = (comp_state_t *) q->q_ptr;
+    if (cp == 0) {
+       DPRINT("cp == 0 in ppp_comp_rput\n");
+       freemsg(mp);
+       return 0;
+    }
+
+    switch (mp->b_datap->db_type) {
+
+    case M_DATA:
+       putq(q, mp);
+       break;
+
+    case M_IOCACK:
+       iop = (struct iocblk *) mp->b_rptr;
+       switch (iop->ioc_cmd) {
+       case PPPIO_GETSTAT:
+           /*
+            * Catch this on the way back from the ppp_ahdl module
+            * so we can fill in the VJ stats.
+            */
+           if (mp->b_cont == 0 || iop->ioc_count != sizeof(struct ppp_stats))
+               break;
+           psp = (struct ppp_stats *) mp->b_cont->b_rptr;
+           psp->vj = cp->vj_comp.stats;
+           break;
+       }
+       putnext(q, mp);
+       break;
+
+    case M_CTL:
+       switch (mp->b_rptr[0]) {
+       case PPPCTL_IERROR:
+           ++cp->stats.ppp_ierrors;
+           break;
+       case PPPCTL_OERROR:
+           ++cp->stats.ppp_oerrors;
+           break;
+       }
+       putnext(q, mp);
+       break;
+
+    default:
+       putnext(q, mp);
+    }
+
+    return 0;
+}
+
+static int
+ppp_comp_rsrv(q)
+    queue_t *q;
+{
+    int proto, rv, i;
+    mblk_t *mp, *dmp = NULL, *np;
+    uchar_t *dp, *iphdr;
+    comp_state_t *cp;
+    int len, hlen, vjlen;
+    u_int iphlen;
+
+    cp = (comp_state_t *) q->q_ptr;
+    if (cp == 0) {
+       DPRINT("cp == 0 in ppp_comp_rsrv\n");
+       return 0;
+    }
+
+    while ((mp = getq(q)) != 0) {
+       /* assert(mp->b_datap->db_type == M_DATA) */
+       if (!canputnext(q)) {
+           putbq(q, mp);
+           break;
+       }
+
+       len = msgdsize(mp);
+       cp->stats.ppp_ibytes += len;
+       cp->stats.ppp_ipackets++;
+
+       /*
+        * First work out the protocol and where the PPP header ends.
+        */
+       i = 0;
+       proto = MSG_BYTE(mp, 0);
+       if (proto == PPP_ALLSTATIONS) {
+           i = 2;
+           proto = MSG_BYTE(mp, 2);
+       }
+       if ((proto & 1) == 0) {
+           ++i;
+           proto = (proto << 8) + MSG_BYTE(mp, i);
+       }
+       hlen = i + 1;
+
+       /*
+        * Now reconstruct a complete, contiguous PPP header at the
+        * start of the packet.
+        */
+       if (hlen < ((cp->flags & DECOMP_AC)? 0: 2)
+                  + ((cp->flags & DECOMP_PROT)? 1: 2)) {
+           /* count these? */
+           goto bad;
+       }
+       if (mp->b_rptr + hlen > mp->b_wptr) {
+           adjmsg(mp, hlen);   /* XXX check this call */
+           hlen = 0;
+       }
+       if (hlen != PPP_HDRLEN) {
+           /*
+            * We need to put some bytes on the front of the packet
+            * to make a full-length PPP header.
+            * If we can put them in *mp, we do, otherwise we
+            * tack another mblk on the front.
+            * XXX we really shouldn't need to carry around
+            * the address and control at this stage.
+            */
+           dp = mp->b_rptr + hlen - PPP_HDRLEN;
+           if (dp < mp->b_datap->db_base || mp->b_datap->db_ref > 1) {
+               np = allocb(PPP_HDRLEN, BPRI_MED);
+               if (np == 0)
+                   goto bad;
+               np->b_cont = mp;
+               mp->b_rptr += hlen;
+               mp = np;
+               dp = mp->b_wptr;
+               mp->b_wptr += PPP_HDRLEN;
+           } else
+               mp->b_rptr = dp;
+
+           dp[0] = PPP_ALLSTATIONS;
+           dp[1] = PPP_UI;
+           dp[2] = proto >> 8;
+           dp[3] = proto;
+       }
+
+       /*
+        * Now see if we have a compressed packet to decompress,
+        * or a CCP packet to take notice of.
+        */
+       proto = PPP_PROTOCOL(mp->b_rptr);
+       if (proto == PPP_CCP) {
+           len = msgdsize(mp);
+           if (mp->b_wptr < mp->b_rptr + len) {
+               PULLUP(mp, len);
+               if (mp == 0)
+                   goto bad;
+           }
+           ppp_comp_ccp(q, mp, 1);
+       } else if (proto == PPP_COMP) {
+           if ((cp->flags & CCP_ISUP)
+               && (cp->flags & CCP_DECOMP_RUN) && cp->rstate
+               && (cp->flags & CCP_ERR) == 0) {
+               rv = (*cp->rcomp->decompress)(cp->rstate, mp, &dmp);
+               switch (rv) {
+               case DECOMP_OK:
+                   freemsg(mp);
+                   mp = dmp;
+                   if (mp == NULL) {
+                       /* no error, but no packet returned either. */
+                       continue;
+                   }
+                   break;
+               case DECOMP_ERROR:
+                   cp->flags |= CCP_ERROR;
+                   ++cp->stats.ppp_ierrors;
+                   putctl1(q->q_next, M_CTL, PPPCTL_IERROR);
+                   break;
+               case DECOMP_FATALERROR:
+                   cp->flags |= CCP_FATALERROR;
+                   ++cp->stats.ppp_ierrors;
+                   putctl1(q->q_next, M_CTL, PPPCTL_IERROR);
+                   break;
+               }
+           }
+       } else if (cp->rstate && (cp->flags & CCP_DECOMP_RUN)) {
+           (*cp->rcomp->incomp)(cp->rstate, mp);
+       }
+
+       /*
+        * Now do VJ decompression.
+        */
+       proto = PPP_PROTOCOL(mp->b_rptr);
+       if (proto == PPP_VJC_COMP || proto == PPP_VJC_UNCOMP) {
+           len = msgdsize(mp) - PPP_HDRLEN;
+           if ((cp->flags & DECOMP_VJC) == 0 || len <= 0)
+               goto bad;
+
+           /*
+            * Advance past the ppp header.
+            * Here we assume that the whole PPP header is in the first mblk.
+            */
+           np = mp;
+           dp = np->b_rptr + PPP_HDRLEN;
+           if (dp >= mp->b_wptr) {
+               np = np->b_cont;
+               dp = np->b_rptr;
+           }
+
+           /*
+            * Make sure we have sufficient contiguous data at this point.
+            */
+           hlen = (proto == PPP_VJC_COMP)? MAX_VJHDR: MAX_IPHDR;
+           if (hlen > len)
+               hlen = len;
+           if (np->b_wptr < dp + hlen || np->b_datap->db_ref > 1) {
+               PULLUP(mp, hlen + PPP_HDRLEN);
+               if (mp == 0)
+                   goto bad;
+               np = mp;
+               dp = np->b_rptr + PPP_HDRLEN;
+           }
+
+           if (proto == PPP_VJC_COMP) {
+               /*
+                * Decompress VJ-compressed packet.
+                * First reset compressor if an input error has occurred.
+                */
+               if (cp->stats.ppp_ierrors != cp->vj_last_ierrors) {
+                   if (cp->flags & DBGLOG)
+                       DPRINT1("ppp%d: resetting VJ\n", cp->unit);
+                   vj_uncompress_err(&cp->vj_comp);
+                   cp->vj_last_ierrors = cp->stats.ppp_ierrors;
+               }
+
+               vjlen = vj_uncompress_tcp(dp, np->b_wptr - dp, len,
+                                         &cp->vj_comp, &iphdr, &iphlen);
+               if (vjlen < 0) {
+                   if (cp->flags & DBGLOG)
+                       DPRINT2("ppp%d: vj_uncomp_tcp failed, pkt len %d\n",
+                               cp->unit, len);
+                   ++cp->vj_last_ierrors;  /* so we don't reset next time */
+                   goto bad;
+               }
+
+               /* drop ppp and vj headers off */
+               if (mp != np) {
+                   freeb(mp);
+                   mp = np;
+               }
+               mp->b_rptr = dp + vjlen;
+
+               /* allocate a new mblk for the ppp and ip headers */
+               if ((np = allocb(iphlen + PPP_HDRLEN + 4, BPRI_MED)) == 0)
+                   goto bad;
+               dp = np->b_rptr;        /* prepend mblk with TCP/IP hdr */
+               dp[0] = PPP_ALLSTATIONS; /* reconstruct PPP header */
+               dp[1] = PPP_UI;
+               dp[2] = PPP_IP >> 8;
+               dp[3] = PPP_IP;
+               bcopy((caddr_t)iphdr, (caddr_t)dp + PPP_HDRLEN, iphlen);
+               np->b_wptr = dp + iphlen + PPP_HDRLEN;
+               np->b_cont = mp;
+
+               /* XXX there seems to be a bug which causes panics in strread
+                  if we make an mbuf with only the IP header in it :-( */
+               if (mp->b_wptr - mp->b_rptr > 4) {
+                   bcopy((caddr_t)mp->b_rptr, (caddr_t)np->b_wptr, 4);
+                   mp->b_rptr += 4;
+                   np->b_wptr += 4;
+               } else {
+                   bcopy((caddr_t)mp->b_rptr, (caddr_t)np->b_wptr,
+                         mp->b_wptr - mp->b_rptr);
+                   np->b_wptr += mp->b_wptr - mp->b_rptr;
+                   np->b_cont = mp->b_cont;
+                   freeb(mp);
+               }
+
+               mp = np;
+
+           } else {
+               /*
+                * "Decompress" a VJ-uncompressed packet.
+                */
+               cp->vj_last_ierrors = cp->stats.ppp_ierrors;
+               if (!vj_uncompress_uncomp(dp, hlen, &cp->vj_comp)) {
+                   if (cp->flags & DBGLOG)
+                       DPRINT2("ppp%d: vj_uncomp_uncomp failed, pkt len %d\n",
+                               cp->unit, len);
+                   ++cp->vj_last_ierrors;  /* don't need to reset next time */
+                   goto bad;
+               }
+               mp->b_rptr[3] = PPP_IP; /* fix up the PPP protocol field */
+           }
+       }
+
+       putnext(q, mp);
+       continue;
+
+    bad:
+       if (mp != 0)
+           freemsg(mp);
+       cp->stats.ppp_ierrors++;
+       putctl1(q->q_next, M_CTL, PPPCTL_IERROR);
+    }
+
+    return 0;
+}
+
+/*
+ * Handle a CCP packet being sent or received.
+ * Here all the data in the packet is in a single mbuf.
+ */
+static void
+ppp_comp_ccp(q, mp, rcvd)
+    queue_t *q;
+    mblk_t *mp;
+    int rcvd;
+{
+    int len, clen;
+    comp_state_t *cp;
+    unsigned char *dp;
+
+    len = msgdsize(mp);
+    if (len < PPP_HDRLEN + CCP_HDRLEN)
+       return;
+
+    cp = (comp_state_t *) q->q_ptr;
+    dp = mp->b_rptr + PPP_HDRLEN;
+    len -= PPP_HDRLEN;
+    clen = CCP_LENGTH(dp);
+    if (clen > len)
+       return;
+
+    switch (CCP_CODE(dp)) {
+    case CCP_CONFREQ:
+    case CCP_TERMREQ:
+    case CCP_TERMACK:
+       cp->flags &= ~CCP_ISUP;
+       break;
+
+    case CCP_CONFACK:
+       if ((cp->flags & (CCP_ISOPEN | CCP_ISUP)) == CCP_ISOPEN
+           && clen >= CCP_HDRLEN + CCP_OPT_MINLEN
+           && clen >= CCP_HDRLEN + CCP_OPT_LENGTH(dp + CCP_HDRLEN)) {
+           if (!rcvd) {
+               if (cp->xstate != NULL
+                   && (*cp->xcomp->comp_init)
+                       (cp->xstate, dp + CCP_HDRLEN, clen - CCP_HDRLEN,
+                        cp->unit, 0, ((cp->flags & DBGLOG) != 0)))
+                   cp->flags |= CCP_COMP_RUN;
+           } else {
+               if (cp->rstate != NULL
+                   && (*cp->rcomp->decomp_init)
+                       (cp->rstate, dp + CCP_HDRLEN, clen - CCP_HDRLEN,
+                        cp->unit, 0, cp->mru, ((cp->flags & DBGLOG) != 0)))
+                   cp->flags = (cp->flags & ~CCP_ERR) | CCP_DECOMP_RUN;
+           }
+       }
+       break;
+
+    case CCP_RESETACK:
+       if (cp->flags & CCP_ISUP) {
+           if (!rcvd) {
+               if (cp->xstate && (cp->flags & CCP_COMP_RUN))
+                   (*cp->xcomp->comp_reset)(cp->xstate);
+           } else {
+               if (cp->rstate && (cp->flags & CCP_DECOMP_RUN)) {
+                   (*cp->rcomp->decomp_reset)(cp->rstate);
+                   cp->flags &= ~CCP_ERROR;
+               }
+           }
+       }
+       break;
+    }
+}
+
+#if 0
+dump_msg(mp)
+    mblk_t *mp;
+{
+    dblk_t *db;
+
+    while (mp != 0) {
+       db = mp->b_datap;
+       DPRINT2("mp=%x cont=%x ", mp, mp->b_cont);
+       DPRINT3("rptr=%x wptr=%x datap=%x\n", mp->b_rptr, mp->b_wptr, db);
+       DPRINT2("  base=%x lim=%x", db->db_base, db->db_lim);
+       DPRINT2(" ref=%d type=%d\n", db->db_ref, db->db_type);
+       mp = mp->b_cont;
+    }
+}
+#endif
+
+static int
+msg_byte(mp, i)
+    mblk_t *mp;
+    unsigned int i;
+{
+    while (mp != 0 && i >= mp->b_wptr - mp->b_rptr)
+       mp = mp->b_cont;
+    if (mp == 0)
+       return -1;
+    return mp->b_rptr[i];
+}