path: root/windows/TapDriver/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);

#if 0
			// 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;
			}
#endif

			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