error.c

/*
 *  TAP-Windows -- A kernel driver to provide virtual tap
 *                 device functionality on Windows.
 *
 *  This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
 *
 *  This source code is Copyright (C) 2002-2010 OpenVPN Technologies, Inc.,
 *  and is released under the GPL version 2 (see below).
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

//-----------------
// DEBUGGING OUTPUT
//-----------------

const char *g_LastErrorFilename;
int g_LastErrorLineNumber;

#if DBG

DebugOutput g_Debug;

BOOLEAN
NewlineExists (const char *str, int len)
{
  while (len-- > 0)
    {
      const char c = *str++;
      if (c == '\n')
	return TRUE;
      else if (c == '\0')
	break;
    }
  return FALSE;
}

VOID
MyDebugInit (unsigned int bufsiz)
{
  NdisZeroMemory (&g_Debug, sizeof (g_Debug));
  g_Debug.text = (char *) MemAlloc (bufsiz, FALSE);
  if (g_Debug.text)
    g_Debug.capacity = bufsiz;
}

VOID
MyDebugFree ()
{
  if (g_Debug.text)
    MemFree (g_Debug.text, g_Debug.capacity);
  NdisZeroMemory (&g_Debug, sizeof (g_Debug));
}

VOID
MyDebugPrint (const unsigned char* format, ...)
{
  if (g_Debug.text && g_Debug.capacity > 0 && CAN_WE_PRINT)
    {
      BOOLEAN owned;
      ACQUIRE_MUTEX_ADAPTIVE (&g_Debug.lock, owned);
      if (owned)
	{
	  const int remaining = (int)g_Debug.capacity - (int)g_Debug.out;

	  if (remaining > 0)
	    {
	      va_list args;
	      NTSTATUS status;
	      char *end;

#ifdef DBG_PRINT
	      va_start (args, format);
	      vDbgPrintEx (DPFLTR_IHVNETWORK_ID, DPFLTR_INFO_LEVEL, format, args);
	      va_end (args);
#endif
	      va_start (args, format);
	      status = RtlStringCchVPrintfExA (g_Debug.text + g_Debug.out,
					       remaining,
					       &end,
					       NULL,
					       STRSAFE_NO_TRUNCATION | STRSAFE_IGNORE_NULLS,
					       format,
					       args);
	      va_end (args);
va_start (args, format);
vDbgPrintEx(DPFLTR_IHVDRIVER_ID , 1, format, args);
va_end (args);
	      if (status == STATUS_SUCCESS)
		g_Debug.out = (unsigned int) (end - g_Debug.text);
	      else
		g_Debug.error = TRUE;
	    }
	  else
	    g_Debug.error = TRUE;

	  RELEASE_MUTEX (&g_Debug.lock);
	}
      else
	g_Debug.error = TRUE;
    }
}

BOOLEAN
GetDebugLine (char *buf, const int len)
{
  static const char *truncated = "[OUTPUT TRUNCATED]\n";
  BOOLEAN ret = FALSE;

  NdisZeroMemory (buf, len);

  if (g_Debug.text && g_Debug.capacity > 0)
    {
      BOOLEAN owned;
      ACQUIRE_MUTEX_ADAPTIVE (&g_Debug.lock, owned);
      if (owned)
	{
	  int i = 0;

	  if (g_Debug.error || NewlineExists (g_Debug.text + g_Debug.in, (int)g_Debug.out - (int)g_Debug.in))
	    {
	      while (i < (len - 1) && g_Debug.in < g_Debug.out)
		{
		  const char c = g_Debug.text[g_Debug.in++];
		  if (c == '\n')
		    break;
		  buf[i++] = c;
		}
	      if (i < len)
		buf[i] = '\0';
	    }

	  if (!i)
	    {
	      if (g_Debug.in == g_Debug.out)
		{
		  g_Debug.in = g_Debug.out = 0;
		  if (g_Debug.error)
		    {
		      const unsigned int tlen = strlen (truncated);
		      if (tlen < g_Debug.capacity)
			{
			  NdisMoveMemory (g_Debug.text, truncated, tlen+1);
			  g_Debug.out = tlen;
			}
		      g_Debug.error = FALSE;
		    }
		}
	    }
	  else
	    ret = TRUE;

	  RELEASE_MUTEX (&g_Debug.lock);
	}      
    }
  return ret;
}

VOID
MyAssert (const unsigned char *file, int line)
{
      DEBUGP (("MYASSERT failed %s/%d\n", file, line));
      KeBugCheckEx (0x0F00BABA,
		    (ULONG_PTR) line,
		    (ULONG_PTR) 0,
		    (ULONG_PTR) 0,
		    (ULONG_PTR) 0);
}

VOID
PrMac (const MACADDR mac)
{
  DEBUGP (("%x:%x:%x:%x:%x:%x",
	    mac[0], mac[1], mac[2],
	    mac[3], mac[4], mac[5]));
}

VOID
PrIP (IPADDR ip_addr)
{
  const unsigned char *ip = (const unsigned char *) &ip_addr;

  DEBUGP (("%d.%d.%d.%d",
	    ip[0], ip[1], ip[2], ip[3]));
}

const char *
PrIPProto (int proto)
{
  switch (proto)
    {
    case IPPROTO_UDP:
      return "UDP";
    case IPPROTO_TCP:
      return "TCP";
    case IPPROTO_ICMP:
      return "ICMP";
    case IPPROTO_IGMP:
      return "IGMP";
    default:
      return "???";
    }
}

VOID
DumpARP (const char *prefix, const ARP_PACKET *arp)
{
  DEBUGP (("%s ARP src=", prefix));
  PrMac (arp->m_MAC_Source);
  DEBUGP ((" dest="));
  PrMac (arp->m_MAC_Destination);
  DEBUGP ((" OP=0x%04x",
	    (int)ntohs(arp->m_ARP_Operation)));
  DEBUGP ((" M=0x%04x(%d)",
	    (int)ntohs(arp->m_MAC_AddressType),
	    (int)arp->m_MAC_AddressSize));
  DEBUGP ((" P=0x%04x(%d)",
	    (int)ntohs(arp->m_PROTO_AddressType),
	    (int)arp->m_PROTO_AddressSize));

  DEBUGP ((" MacSrc="));
  PrMac (arp->m_ARP_MAC_Source);
  DEBUGP ((" MacDest="));
  PrMac (arp->m_ARP_MAC_Destination);

  DEBUGP ((" IPSrc="));
  PrIP (arp->m_ARP_IP_Source);
  DEBUGP ((" IPDest="));
  PrIP (arp->m_ARP_IP_Destination);

  DEBUGP (("\n"));
}

struct ethpayload {
  ETH_HEADER eth;
  UCHAR payload[DEFAULT_PACKET_LOOKAHEAD];
};

VOID
DumpPacket2 (const char *prefix,
	     const ETH_HEADER *eth,
	     const unsigned char *data,
	     unsigned int len)
{
  struct ethpayload *ep = (struct ethpayload *) MemAlloc (sizeof (struct ethpayload), TRUE);
  if (ep)
    {
      if (len > DEFAULT_PACKET_LOOKAHEAD)
	len = DEFAULT_PACKET_LOOKAHEAD;
      ep->eth = *eth;
      NdisMoveMemory (ep->payload, data, len);
      DumpPacket (prefix, (unsigned char *) ep, sizeof (ETH_HEADER) + len);
      MemFree (ep, sizeof (struct ethpayload));
    }
}

VOID
DumpPacket (const char *prefix,
	    const unsigned char *data,
	    unsigned int len)
{
  const ETH_HEADER *eth = (const ETH_HEADER *) data;
  const IPHDR *ip = (const IPHDR *) (data + sizeof (ETH_HEADER));

  if (len < sizeof (ETH_HEADER))
    {
      DEBUGP (("%s TRUNCATED PACKET LEN=%d\n", prefix, len));
      return;
    }

  // ARP Packet?
  if (len >= sizeof (ARP_PACKET) && eth->proto == htons (ETH_P_ARP))
    {
      DumpARP (prefix, (const ARP_PACKET *) data);
      return;
    }

  // IPv4 packet?
  if (len >= (sizeof (IPHDR) + sizeof (ETH_HEADER))
      && eth->proto == htons (ETH_P_IP)
      && IPH_GET_VER (ip->version_len) == 4)
    {
      const int hlen = IPH_GET_LEN (ip->version_len);
      const int blen = len - sizeof (ETH_HEADER);
      BOOLEAN did = FALSE;

      DEBUGP (("%s IPv4 %s[%d]", prefix, PrIPProto (ip->protocol), len));

      if (!(ntohs (ip->tot_len) == blen && hlen <= blen))
	{
	  DEBUGP ((" XXX"));
	  return;
	}
      
      // TCP packet?
      if (ip->protocol == IPPROTO_TCP
	  && blen - hlen >= (sizeof (TCPHDR)))
	{
	  const TCPHDR *tcp = (TCPHDR *) (data + sizeof (ETH_HEADER) + hlen);
	  DEBUGP ((" "));
	  PrIP (ip->saddr);
	  DEBUGP ((":%d", ntohs (tcp->source)));
	  DEBUGP ((" -> "));
	  PrIP (ip->daddr);
	  DEBUGP ((":%d", ntohs (tcp->dest)));
	  did = TRUE;
	}

      // UDP packet?
      else if ((ntohs (ip->frag_off) & IP_OFFMASK) == 0
	       && ip->protocol == IPPROTO_UDP
	       && blen - hlen >= (sizeof (UDPHDR)))
	{
	  const UDPHDR *udp = (UDPHDR *) (data + sizeof (ETH_HEADER) + hlen);
	  
	  // DHCP packet?
	  if ((udp->dest == htons (BOOTPC_PORT) || udp->dest == htons (BOOTPS_PORT))
	      && blen - hlen >= (sizeof (UDPHDR) + sizeof (DHCP)))
	    {
	      const DHCP *dhcp = (DHCP *) (data
					   + hlen
					   + sizeof (ETH_HEADER)
					   + sizeof (UDPHDR));
	      
	      int optlen = len
		- sizeof (ETH_HEADER)
		- hlen
		- sizeof (UDPHDR)
		- sizeof (DHCP);

	      if (optlen < 0)
		optlen = 0;

	      DumpDHCP (eth, ip, udp, dhcp, optlen);
	      did = TRUE;
	    }

	  if (!did)
	    {
	      DEBUGP ((" "));
	      PrIP (ip->saddr);
	      DEBUGP ((":%d", ntohs (udp->source)));
	      DEBUGP ((" -> "));
	      PrIP (ip->daddr);
	      DEBUGP ((":%d", ntohs (udp->dest)));
	      did = TRUE;
	    }
	}

      if (!did)
	{
	  DEBUGP ((" ipproto=%d ", ip->protocol));
	  PrIP (ip->saddr);
	  DEBUGP ((" -> "));
	  PrIP (ip->daddr);
	}

      DEBUGP (("\n"));
      return;
    }

  {
    DEBUGP (("%s ??? src=", prefix));
    PrMac (eth->src);
    DEBUGP ((" dest="));
    PrMac (eth->dest);
    DEBUGP ((" proto=0x%04x len=%d\n",
	      (int) ntohs(eth->proto),
	      len));
  }
}

#endif