1 files changed, 576 insertions, 0 deletions

diff --git a/usr.sbin/ppp/hdlc.c b/usr.sbin/ppp/hdlc.c
new file mode 100644
index 000000000000..ca51a647ea2e
--- /dev/null
+++ b/usr.sbin/ppp/hdlc.c
@@ -0,0 +1,576 @@
+/*
+ *	     PPP High Level Link Control (HDLC) Module
+ *
+ *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
+ *
+ *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the Internet Initiative Japan, Inc.  The name of the
+ * IIJ may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: hdlc.c,v 1.27 1998/01/10 01:55:10 brian Exp $
+ *
+ *	TODO:
+ */
+#include <sys/param.h>
+#include <netinet/in.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <termios.h>
+
+#include "command.h"
+#include "mbuf.h"
+#include "log.h"
+#include "defs.h"
+#include "timer.h"
+#include "fsm.h"
+#include "hdlc.h"
+#include "lcpproto.h"
+#include "ipcp.h"
+#include "ip.h"
+#include "vjcomp.h"
+#include "pap.h"
+#include "chap.h"
+#include "lcp.h"
+#include "async.h"
+#include "lqr.h"
+#include "loadalias.h"
+#include "vars.h"
+#include "modem.h"
+#include "ccp.h"
+
+static struct hdlcstat {
+  int badfcs;
+  int badaddr;
+  int badcommand;
+  int unknownproto;
+}        HdlcStat;
+
+static int ifOutPackets;
+static int ifOutOctets;
+static int ifOutLQRs;
+
+static struct protostat {
+  u_short number;
+  const char *name;
+  u_long in_count;
+  u_long out_count;
+} ProtocolStat[] = {
+  { PROTO_IP, "IP" },
+  { PROTO_VJUNCOMP, "VJ_UNCOMP" },
+  { PROTO_VJCOMP, "VJ_COMP" },
+  { PROTO_COMPD, "COMPD" },
+  { PROTO_LCP, "LCP" },
+  { PROTO_IPCP, "IPCP" },
+  { PROTO_CCP, "CCP" },
+  { PROTO_PAP, "PAP" },
+  { PROTO_LQR, "LQR" },
+  { PROTO_CHAP, "CHAP" },
+  { 0, "Others" }
+};
+
+static u_short const fcstab[256] = {
+   /* 00 */ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+   /* 08 */ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+   /* 10 */ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+   /* 18 */ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+   /* 20 */ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+   /* 28 */ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+   /* 30 */ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+   /* 38 */ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+   /* 40 */ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+   /* 48 */ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+   /* 50 */ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+   /* 58 */ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+   /* 60 */ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+   /* 68 */ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+   /* 70 */ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+   /* 78 */ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+   /* 80 */ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+   /* 88 */ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+   /* 90 */ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+   /* 98 */ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+   /* a0 */ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+   /* a8 */ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+   /* b0 */ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+   /* b8 */ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+   /* c0 */ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+   /* c8 */ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+   /* d0 */ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+   /* d8 */ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+   /* e0 */ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+   /* e8 */ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+   /* f0 */ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+   /* f8 */ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+};
+
+u_char EscMap[33];
+
+void
+HdlcInit()
+{
+  ifOutOctets = 0;
+  ifOutPackets = 0;
+  ifOutLQRs = 0;
+}
+
+/*
+ *  HDLC FCS computation. Read RFC 1171 Appendix B and CCITT X.25 section
+ *  2.27 for further details.
+ */
+inline u_short
+HdlcFcs(u_short fcs, u_char * cp, int len)
+{
+  while (len--)
+    fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
+  return (fcs);
+}
+
+static inline u_short
+HdlcFcsBuf(u_short fcs, struct mbuf *m)
+{
+  int len;
+  u_char *pos, *end;
+
+  len = plength(m);
+  pos = MBUF_CTOP(m);
+  end = pos + m->cnt;
+  while (len--) {
+    fcs = (fcs >> 8) ^ fcstab[(fcs ^ *pos++) & 0xff];
+    if (pos == end && len) {
+      m = m->next;
+      pos = MBUF_CTOP(m);
+      end = pos + m->cnt;
+    }
+  }
+  return (fcs);
+}
+
+void
+HdlcOutput(int pri, u_short proto, struct mbuf * bp)
+{
+  struct mbuf *mhp, *mfcs;
+  struct protostat *statp;
+  struct lqrdata *lqr;
+  u_char *cp;
+  u_short fcs;
+
+  if ((proto & 0xfff1) == 0x21)		/* Network Layer protocol */
+    if (CcpFsm.state == ST_OPENED)
+      if (CcpOutput(pri, proto, bp))
+        return;
+
+  if (DEV_IS_SYNC)
+    mfcs = NULL;
+  else
+    mfcs = mballoc(2, MB_HDLCOUT);
+
+  mhp = mballoc(4, MB_HDLCOUT);
+  mhp->cnt = 0;
+  cp = MBUF_CTOP(mhp);
+  if (proto == PROTO_LCP || LcpInfo.his_acfcomp == 0) {
+    *cp++ = HDLC_ADDR;
+    *cp++ = HDLC_UI;
+    mhp->cnt += 2;
+  }
+
+  /*
+   * If possible, compress protocol field.
+   */
+  if (LcpInfo.his_protocomp && (proto & 0xff00) == 0) {
+    *cp++ = proto;
+    mhp->cnt++;
+  } else {
+    *cp++ = proto >> 8;
+    *cp = proto & 0377;
+    mhp->cnt += 2;
+  }
+  mhp->next = bp;
+  while (bp->next != NULL)
+    bp = bp->next;
+  bp->next = mfcs;
+  bp = mhp->next;
+
+  lqr = &MyLqrData;
+  lqr->PeerOutPackets = ifOutPackets++;
+  ifOutOctets += plength(mhp) + 1;
+  lqr->PeerOutOctets = ifOutOctets;
+
+  if (proto == PROTO_LQR) {
+    lqr->MagicNumber = LcpInfo.want_magic;
+    lqr->LastOutLQRs = HisLqrData.PeerOutLQRs;
+    lqr->LastOutPackets = HisLqrData.PeerOutPackets;
+    lqr->LastOutOctets = HisLqrData.PeerOutOctets;
+    lqr->PeerInLQRs = HisLqrSave.SaveInLQRs;
+    lqr->PeerInPackets = HisLqrSave.SaveInPackets;
+    lqr->PeerInDiscards = HisLqrSave.SaveInDiscards;
+    lqr->PeerInErrors = HisLqrSave.SaveInErrors;
+    lqr->PeerInOctets = HisLqrSave.SaveInOctets;
+    lqr->PeerOutLQRs = ++ifOutLQRs;
+    LqrDump("LqrOutput", lqr);
+    LqrChangeOrder(lqr, (struct lqrdata *) (MBUF_CTOP(bp)));
+  }
+  if (!DEV_IS_SYNC) {
+    mfcs->cnt = 0;
+    fcs = HdlcFcsBuf(INITFCS, mhp);
+    fcs = ~fcs;
+    cp = MBUF_CTOP(mfcs);
+    *cp++ = fcs & 0377;		/* Low byte first!! */
+    *cp++ = fcs >> 8;
+    mfcs->cnt = 2;
+  }
+  LogDumpBp(LogHDLC, "HdlcOutput", mhp);
+  for (statp = ProtocolStat; statp->number; statp++)
+    if (statp->number == proto)
+      break;
+  statp->out_count++;
+
+  LogPrintf(LogDEBUG, "HdlcOutput: proto = 0x%04x\n", proto);
+
+  if (DEV_IS_SYNC)
+    ModemOutput(pri, mhp);
+  else
+    AsyncOutput(pri, mhp, proto);
+}
+
+/* Check out the latest ``Assigned numbers'' rfc (rfc1700.txt) */
+static struct {
+  u_short from;
+  u_short to;
+  const char *name;
+} protocols[] = {
+  { 0x0001, 0x0001, "Padding Protocol" },
+  { 0x0003, 0x001f, "reserved (transparency inefficient)" },
+  { 0x0021, 0x0021, "Internet Protocol" },
+  { 0x0023, 0x0023, "OSI Network Layer" },
+  { 0x0025, 0x0025, "Xerox NS IDP" },
+  { 0x0027, 0x0027, "DECnet Phase IV" },
+  { 0x0029, 0x0029, "Appletalk" },
+  { 0x002b, 0x002b, "Novell IPX" },
+  { 0x002d, 0x002d, "Van Jacobson Compressed TCP/IP" },
+  { 0x002f, 0x002f, "Van Jacobson Uncompressed TCP/IP" },
+  { 0x0031, 0x0031, "Bridging PDU" },
+  { 0x0033, 0x0033, "Stream Protocol (ST-II)" },
+  { 0x0035, 0x0035, "Banyan Vines" },
+  { 0x0037, 0x0037, "reserved (until 1993)" },
+  { 0x0039, 0x0039, "AppleTalk EDDP" },
+  { 0x003b, 0x003b, "AppleTalk SmartBuffered" },
+  { 0x003d, 0x003d, "Multi-Link" },
+  { 0x003f, 0x003f, "NETBIOS Framing" },
+  { 0x0041, 0x0041, "Cisco Systems" },
+  { 0x0043, 0x0043, "Ascom Timeplex" },
+  { 0x0045, 0x0045, "Fujitsu Link Backup and Load Balancing (LBLB)" },
+  { 0x0047, 0x0047, "DCA Remote Lan" },
+  { 0x0049, 0x0049, "Serial Data Transport Protocol (PPP-SDTP)" },
+  { 0x004b, 0x004b, "SNA over 802.2" },
+  { 0x004d, 0x004d, "SNA" },
+  { 0x004f, 0x004f, "IP6 Header Compression" },
+  { 0x0051, 0x0051, "KNX Bridging Data" },
+  { 0x0053, 0x0053, "Encryption" },
+  { 0x0055, 0x0055, "Individual Link Encryption" },
+  { 0x006f, 0x006f, "Stampede Bridging" },
+  { 0x0071, 0x0071, "BAP Bandwidth Allocation Protocol" },
+  { 0x0073, 0x0073, "MP+ Protocol" },
+  { 0x007d, 0x007d, "reserved (Control Escape)" },
+  { 0x007f, 0x007f, "reserved (compression inefficient)" },
+  { 0x00cf, 0x00cf, "reserved (PPP NLPID)" },
+  { 0x00fb, 0x00fb, "compression on single link in multilink group" },
+  { 0x00fd, 0x00fd, "1st choice compression" },
+  { 0x00ff, 0x00ff, "reserved (compression inefficient)" },
+  { 0x0200, 0x02ff, "(compression inefficient)" },
+  { 0x0201, 0x0201, "802.1d Hello Packets" },
+  { 0x0203, 0x0203, "IBM Source Routing BPDU" },
+  { 0x0205, 0x0205, "DEC LANBridge100 Spanning Tree" },
+  { 0x0207, 0x0207, "Cisco Discovery Protocol" },
+  { 0x0209, 0x0209, "Netcs Twin Routing" },
+  { 0x0231, 0x0231, "Luxcom" },
+  { 0x0233, 0x0233, "Sigma Network Systems" },
+  { 0x0235, 0x0235, "Apple Client Server Protocol" },
+  { 0x1e00, 0x1eff, "(compression inefficient)" },
+  { 0x4001, 0x4001, "Cray Communications Control Protocol" },
+  { 0x4003, 0x4003, "CDPD Mobile Network Registration Protocol" },
+  { 0x4021, 0x4021, "Stacker LZS" },
+  { 0x8001, 0x801f, "Not Used - reserved" },
+  { 0x8021, 0x8021, "Internet Protocol Control Protocol" },
+  { 0x8023, 0x8023, "OSI Network Layer Control Protocol" },
+  { 0x8025, 0x8025, "Xerox NS IDP Control Protocol" },
+  { 0x8027, 0x8027, "DECnet Phase IV Control Protocol" },
+  { 0x8029, 0x8029, "Appletalk Control Protocol" },
+  { 0x802b, 0x802b, "Novell IPX Control Protocol" },
+  { 0x802d, 0x802d, "reserved" },
+  { 0x802f, 0x802f, "reserved" },
+  { 0x8031, 0x8031, "Bridging NCP" },
+  { 0x8033, 0x8033, "Stream Protocol Control Protocol" },
+  { 0x8035, 0x8035, "Banyan Vines Control Protocol" },
+  { 0x8037, 0x8037, "reserved till 1993" },
+  { 0x8039, 0x8039, "reserved" },
+  { 0x803b, 0x803b, "reserved" },
+  { 0x803d, 0x803d, "Multi-Link Control Protocol" },
+  { 0x803f, 0x803f, "NETBIOS Framing Control Protocol" },
+  { 0x8041, 0x8041, "Cisco Systems Control Protocol" },
+  { 0x8043, 0x8043, "Ascom Timeplex" },
+  { 0x8045, 0x8045, "Fujitsu LBLB Control Protocol" },
+  { 0x8047, 0x8047, "DCA Remote Lan Network Control Protocol (RLNCP)" },
+  { 0x8049, 0x8049, "Serial Data Control Protocol (PPP-SDCP)" },
+  { 0x804b, 0x804b, "SNA over 802.2 Control Protocol" },
+  { 0x804d, 0x804d, "SNA Control Protocol" },
+  { 0x804f, 0x804f, "IP6 Header Compression Control Protocol" },
+  { 0x8051, 0x8051, "KNX Bridging Control Protocol" },
+  { 0x8053, 0x8053, "Encryption Control Protocol" },
+  { 0x8055, 0x8055, "Individual Link Encryption Control Protocol" },
+  { 0x806f, 0x806f, "Stampede Bridging Control Protocol" },
+  { 0x8073, 0x8073, "MP+ Control Protocol" },
+  { 0x8071, 0x8071, "BACP Bandwidth Allocation Control Protocol" },
+  { 0x807d, 0x807d, "Not Used - reserved" },
+  { 0x80cf, 0x80cf, "Not Used - reserved" },
+  { 0x80fb, 0x80fb, "compression on single link in multilink group control" },
+  { 0x80fd, 0x80fd, "Compression Control Protocol" },
+  { 0x80ff, 0x80ff, "Not Used - reserved" },
+  { 0x8207, 0x8207, "Cisco Discovery Protocol Control" },
+  { 0x8209, 0x8209, "Netcs Twin Routing" },
+  { 0x8235, 0x8235, "Apple Client Server Protocol Control" },
+  { 0xc021, 0xc021, "Link Control Protocol" },
+  { 0xc023, 0xc023, "Password Authentication Protocol" },
+  { 0xc025, 0xc025, "Link Quality Report" },
+  { 0xc027, 0xc027, "Shiva Password Authentication Protocol" },
+  { 0xc029, 0xc029, "CallBack Control Protocol (CBCP)" },
+  { 0xc081, 0xc081, "Container Control Protocol" },
+  { 0xc223, 0xc223, "Challenge Handshake Authentication Protocol" },
+  { 0xc225, 0xc225, "RSA Authentication Protocol" },
+  { 0xc227, 0xc227, "Extensible Authentication Protocol" },
+  { 0xc26f, 0xc26f, "Stampede Bridging Authorization Protocol" },
+  { 0xc281, 0xc281, "Proprietary Authentication Protocol" },
+  { 0xc283, 0xc283, "Proprietary Authentication Protocol" },
+  { 0xc481, 0xc481, "Proprietary Node ID Authentication Protocol" }
+};
+
+#define NPROTOCOLS (sizeof protocols/sizeof protocols[0])
+
+static const char *
+Protocol2Nam(u_short proto)
+{
+  int f;
+
+  for (f = 0; f < NPROTOCOLS; f++)
+    if (proto >= protocols[f].from && proto <= protocols[f].to)
+      return protocols[f].name;
+    else if (proto < protocols[f].from)
+      break;
+  return "unrecognised protocol";
+}
+
+static void
+DecodePacket(u_short proto, struct mbuf * bp)
+{
+  u_char *cp;
+
+  LogPrintf(LogDEBUG, "DecodePacket: proto = 0x%04x\n", proto);
+
+  /*
+   * If proto isn't PROTO_COMPD, we still want to pass it to the
+   * decompression routines so that the dictionary's updated
+   */
+  if (CcpFsm.state == ST_OPENED)
+    if (proto == PROTO_COMPD) {
+      if ((bp = CompdInput(&proto, bp)) == NULL)
+        return;
+    } else if ((proto & 0xfff1) == 0x21)	/* Network Layer protocol */
+      CcpDictSetup(proto, bp);
+
+  switch (proto) {
+  case PROTO_LCP:
+    LcpInput(bp);
+    break;
+  case PROTO_PAP:
+    PapInput(bp);
+    break;
+  case PROTO_LQR:
+    HisLqrSave.SaveInLQRs++;
+    LqrInput(bp);
+    break;
+  case PROTO_CHAP:
+    ChapInput(bp);
+    break;
+  case PROTO_VJUNCOMP:
+  case PROTO_VJCOMP:
+    bp = VjCompInput(bp, proto);
+    if (bp == NULL) {
+      break;
+    }
+    /* fall down */
+  case PROTO_IP:
+    IpInput(bp);
+    break;
+  case PROTO_IPCP:
+    IpcpInput(bp);
+    break;
+  case PROTO_CCP:
+    CcpInput(bp);
+    break;
+  default:
+    LogPrintf(LogPHASE, "Unknown protocol 0x%04x (%s)\n",
+              proto, Protocol2Nam(proto));
+    bp->offset -= 2;
+    bp->cnt += 2;
+    cp = MBUF_CTOP(bp);
+    LcpSendProtoRej(cp, bp->cnt);
+    HisLqrSave.SaveInDiscards++;
+    HdlcStat.unknownproto++;
+    pfree(bp);
+    break;
+  }
+}
+
+int
+ReportProtStatus(struct cmdargs const *arg)
+{
+  struct protostat *statp;
+  int cnt;
+
+  statp = ProtocolStat;
+  statp--;
+  cnt = 0;
+  fprintf(VarTerm, "    Protocol     in        out      Protocol      in       out\n");
+  do {
+    statp++;
+    fprintf(VarTerm, "   %-9s: %8lu, %8lu",
+	    statp->name, statp->in_count, statp->out_count);
+    if (++cnt == 2) {
+      fprintf(VarTerm, "\n");
+      cnt = 0;
+    }
+  } while (statp->number);
+  if (cnt)
+    fprintf(VarTerm, "\n");
+  return (0);
+}
+
+int
+ReportHdlcStatus(struct cmdargs const *arg)
+{
+  struct hdlcstat *hp = &HdlcStat;
+
+  if (VarTerm) {
+    fprintf(VarTerm, "HDLC level errors\n\n");
+    fprintf(VarTerm, "FCS: %u  ADDR: %u  COMMAND: %u  PROTO: %u\n",
+	    hp->badfcs, hp->badaddr, hp->badcommand, hp->unknownproto);
+  }
+  return 0;
+}
+
+static struct hdlcstat laststat;
+
+void
+HdlcErrorCheck()
+{
+  struct hdlcstat *hp = &HdlcStat;
+  struct hdlcstat *op = &laststat;
+
+  if (memcmp(hp, op, sizeof laststat)) {
+    LogPrintf(LogPHASE, "HDLC errors -> FCS: %u ADDR: %u COMD: %u PROTO: %u\n",
+	      hp->badfcs - op->badfcs, hp->badaddr - op->badaddr,
+      hp->badcommand - op->badcommand, hp->unknownproto - op->unknownproto);
+  }
+  laststat = HdlcStat;
+}
+
+void
+HdlcInput(struct mbuf * bp)
+{
+  u_short fcs, proto;
+  u_char *cp, addr, ctrl;
+  struct protostat *statp;
+
+  LogDumpBp(LogHDLC, "HdlcInput:", bp);
+  if (DEV_IS_SYNC)
+    fcs = GOODFCS;
+  else
+    fcs = HdlcFcs(INITFCS, MBUF_CTOP(bp), bp->cnt);
+  HisLqrSave.SaveInOctets += bp->cnt + 1;
+
+  LogPrintf(LogDEBUG, "HdlcInput: fcs = %04x (%s)\n",
+	    fcs, (fcs == GOODFCS) ? "good" : "bad");
+  if (fcs != GOODFCS) {
+    HisLqrSave.SaveInErrors++;
+    LogPrintf(LogDEBUG, "HdlcInput: Bad FCS\n");
+    HdlcStat.badfcs++;
+    pfree(bp);
+    return;
+  }
+  if (!DEV_IS_SYNC)
+    bp->cnt -= 2;		/* discard FCS part */
+
+  if (bp->cnt < 2) {		/* XXX: raise this bar ? */
+    pfree(bp);
+    return;
+  }
+  cp = MBUF_CTOP(bp);
+
+  if (!LcpInfo.want_acfcomp) {
+
+    /*
+     * We expect that packet is not compressed.
+     */
+    addr = *cp++;
+    if (addr != HDLC_ADDR) {
+      HisLqrSave.SaveInErrors++;
+      HdlcStat.badaddr++;
+      LogPrintf(LogDEBUG, "HdlcInput: addr %02x\n", *cp);
+      pfree(bp);
+      return;
+    }
+    ctrl = *cp++;
+    if (ctrl != HDLC_UI) {
+      HisLqrSave.SaveInErrors++;
+      HdlcStat.badcommand++;
+      LogPrintf(LogDEBUG, "HdlcInput: %02x\n", *cp);
+      pfree(bp);
+      return;
+    }
+    bp->offset += 2;
+    bp->cnt -= 2;
+  } else if (cp[0] == HDLC_ADDR && cp[1] == HDLC_UI) {
+
+    /*
+     * We can receive compressed packet, but peer still send uncompressed
+     * packet to me.
+     */
+    cp += 2;
+    bp->offset += 2;
+    bp->cnt -= 2;
+  }
+  if (LcpInfo.want_protocomp) {
+    proto = 0;
+    cp--;
+    do {
+      cp++;
+      bp->offset++;
+      bp->cnt--;
+      proto = proto << 8;
+      proto += *cp;
+    } while (!(proto & 1));
+  } else {
+    proto = *cp++ << 8;
+    proto |= *cp++;
+    bp->offset += 2;
+    bp->cnt -= 2;
+  }
+
+  for (statp = ProtocolStat; statp->number; statp++)
+    if (statp->number == proto)
+      break;
+  statp->in_count++;
+  HisLqrSave.SaveInPackets++;
+
+  DecodePacket(proto, bp);
+}