X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Modules%2FIPStack%2Fipv4.c;h=b77581eb0939c80c5e737385b7d10af947d0651c;hb=7941d6b368acb0abc17e6a77ffaf7b4c306b67ab;hp=aff593a6129bc250725c759b81256a4ce88888e6;hpb=c0078bf13fa69e05235341a2863c873b7a76180a;p=tpg%2Facess2.git

diff --git a/Modules/IPStack/ipv4.c b/Modules/IPStack/ipv4.c
index aff593a6..b77581eb 100644
--- a/Modules/IPStack/ipv4.c
+++ b/Modules/IPStack/ipv4.c
@@ -5,6 +5,7 @@
 #include "ipstack.h"
 #include "link.h"
 #include "ipv4.h"
+#include "firewall.h"
 
 #define DEFAULT_TTL	32
 
@@ -20,7 +21,7 @@ extern tMacAddr	ARP_Resolve4(tInterface *Interface, tIPv4 Address);
 void	IPv4_int_GetPacket(tAdapter *Interface, tMacAddr From, int Length, void *Buffer);
 tInterface	*IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
 Uint32	IPv4_Netmask(int FixedBits);
-Uint16	IPv4_Checksum(void *Buf, int Size);
+Uint16	IPv4_Checksum(const void *Buf, int Size);
  int	IPv4_Ping(tInterface *Iface, tIPv4 Addr);
 
 // === GLOBALS ===
@@ -28,7 +29,7 @@ tIPCallback	gaIPv4_Callbacks[256];
 
 // === CODE ===
 /**
- * \fn int IPv4_Initialise()
+ * \brief Initialise the IPv4 Code
  */
 int IPv4_Initialise()
 {
@@ -38,8 +39,9 @@ int IPv4_Initialise()
 }
 
 /**
- * \fn int IPv4_RegisterCallback( int ID, tIPCallback Callback )
  * \brief Registers a callback
+ * \param ID	8-bit packet type ID
+ * \param Callback	Callback function
  */
 int IPv4_RegisterCallback(int ID, tIPCallback Callback)
 {
@@ -57,13 +59,33 @@ int IPv4_RegisterCallback(int ID, tIPCallback Callback)
  * \param ID	Some random ID number
  * \param Length	Data Length
  * \param Data	Packet Data
+ * \return Boolean Success
  */
-int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, int Length, void *Data)
+int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, int Length, const void *Data)
 {
 	tMacAddr	to = ARP_Resolve4(Iface, Address);
 	 int	bufSize = sizeof(tIPv4Header) + Length;
 	char	buf[bufSize];
 	tIPv4Header	*hdr = (void*)buf;
+	 int	ret;
+	
+	if( MAC_EQU(to, cMAC_ZERO) ) {
+		// No route to host
+		Log_Notice("IPv4", "No route to host %i.%i.%i.%i",
+			Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
+		return 0;
+	}
+	
+	// OUTPUT Firewall rule go here
+	ret = IPTables_TestChain("OUTPUT",
+		4, (tIPv4*)Iface->Address, &Address,
+		Protocol, 0,
+		Length, Data);
+	if(ret > 0) {
+		// Just drop it (with an error)
+		Log_Notice("IPv4", "Firewall dropped packet");
+		return 0;
+	}
 	
 	memcpy(&hdr->Options[0], Data, Length);
 	hdr->Version = 4;
@@ -81,9 +103,9 @@ int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, int
 	hdr->TTL = DEFAULT_TTL;
 	hdr->Protocol = Protocol;
 	hdr->HeaderChecksum = 0;	// Will be set later
-	hdr->Source = Iface->IP4.Address;
+	hdr->Source = *(tIPv4*)Iface->Address;
 	hdr->Destination = Address;
-	hdr->HeaderChecksum = IPv4_Checksum(hdr, sizeof(tIPv4Header));
+	hdr->HeaderChecksum = htons(IPv4_Checksum(hdr, sizeof(tIPv4Header)));
 	
 	Log_Log("IPv4", "Sending packet to %i.%i.%i.%i",
 		Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
@@ -101,20 +123,22 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
 	tInterface	*iface;
 	Uint8	*data;
 	 int	dataLength;
+	 int	ret;
+	
 	if(Length < sizeof(tIPv4Header))	return;
 	
 	#if 0
 	//Log_Log("IPv4", "Version = %i", hdr->Version);
 	//Log_Log("IPv4", "HeaderLength = %i", hdr->HeaderLength);
 	//Log_Log("IPv4", "DiffServices = %i", hdr->DiffServices);
-	Log_Log("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) );
+	Log_Debug("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) );
 	//Log_Log("IPv4", "Identifcation = %i", ntohs(hdr->Identifcation) );
 	//Log_Log("IPv4", "TTL = %i", hdr->TTL );
-	Log_Log("IPv4", "Protocol = %i", hdr->Protocol );
+	Log_Debug("IPv4", "Protocol = %i", hdr->Protocol );
 	//Log_Log("IPv4", "HeaderChecksum = 0x%x", ntohs(hdr->HeaderChecksum) );
-	Log_Log("IPv4", "Source = %i.%i.%i.%i",
+	Log_Debug("IPv4", "Source = %i.%i.%i.%i",
 		hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3] );
-	Log_Log("IPv4", "Destination = %i.%i.%i.%i",
+	Log_Debug("IPv4", "Destination = %i.%i.%i.%i",
 		hdr->Destination.B[0], hdr->Destination.B[1],
 		hdr->Destination.B[2], hdr->Destination.B[3] );
 	#endif	
@@ -126,7 +150,17 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
 	}
 	
 	// Check Header checksum
-	//TODO
+	{
+		Uint16	hdrVal, compVal;
+		hdrVal = ntohs(hdr->HeaderChecksum);
+		hdr->HeaderChecksum = 0;
+		compVal = IPv4_Checksum(hdr, hdr->HeaderLength * 4);
+		if(hdrVal != compVal) {
+			Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal);
+			return ;
+		}
+		hdr->HeaderChecksum = hdrVal;
+	}
 	
 	// Check Packet length
 	if( ntohs(hdr->TotalLength) > Length) {
@@ -134,29 +168,97 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
 		return;
 	}
 	
-	// Get Interface (allowing broadcasts)
-	iface = IPv4_GetInterface(Adapter, hdr->Destination, 1);
-	if(!iface) {
-		Log_Log("IPv4", "Ignoring Packet (Not for us)");
-		return;	// Not for us? Well, let's ignore it
-	}
+	// TODO: Handle packet fragmentation
 	
-	// Defragment
-	//TODO
 	
+	// Get Data and Data Length
 	dataLength = ntohs(hdr->TotalLength) - sizeof(tIPv4Header);
 	data = &hdr->Options[0];
 	
+	// Get Interface (allowing broadcasts)
+	iface = IPv4_GetInterface(Adapter, hdr->Destination, 1);
+	
+	// Firewall rules
+	if( iface ) {
+		// Incoming Packets
+		ret = IPTables_TestChain("INPUT",
+			4, &hdr->Source, &hdr->Destination,
+			hdr->Protocol, 0,
+			dataLength, data
+			);
+	}
+	else {
+		// Routed packets
+		ret = IPTables_TestChain("FORWARD",
+			4, &hdr->Source, &hdr->Destination,
+			hdr->Protocol, 0,
+			dataLength, data
+			);
+	}
+	switch(ret)
+	{
+	// 0 - Allow
+	case 0:	break;
+	// 1 - Silent Drop
+	case 1:
+		Log_Debug("IPv4", "Silently dropping packet");
+		return ;
+	case -1:
+		// Bad rule
+		break ;
+	// Unknown, silent drop
+	default:
+		Log_Warning("IPv4", "Unknown firewall rule");
+		return ;
+	}
+	
+	// Routing
+	if(!iface)
+	{
+		tMacAddr	to;
+		tRoute	*rt;
+		
+		Log_Debug("IPv4", "Route the packet");
+		// Drop the packet if the TTL is zero
+		if( hdr->TTL == 0 ) {
+			Log_Warning("IPv4", "TODO: Sent ICMP-Timeout when TTL exceeded");
+			return ;
+		}
+		
+		hdr->TTL --;
+		
+		rt = IPStack_FindRoute(4, NULL, &hdr->Destination);	// Get the route (gets the interface)
+		to = ARP_Resolve4(rt->Interface, hdr->Destination);	// Resolve address
+		if( MAC_EQU(to, cMAC_ZERO) )
+			return ;
+		
+		// Send packet
+		Log_Log("IPv4", "Forwarding packet to %i.%i.%i.%i (via %i.%i.%i.%i)",
+			hdr->Destination.B[0], hdr->Destination.B[1],
+			hdr->Destination.B[2], hdr->Destination.B[3],
+			((tIPv4*)rt->NextHop)->B[0], ((tIPv4*)rt->NextHop)->B[1],
+			((tIPv4*)rt->NextHop)->B[2], ((tIPv4*)rt->NextHop)->B[3]);
+		Link_SendPacket(rt->Interface->Adapter, IPV4_ETHERNET_ID, to, Length, Buffer);
+		
+		
+		return ;
+	}
+	
 	// Send it on
-	if( gaIPv4_Callbacks[hdr->Protocol] )
-		gaIPv4_Callbacks[hdr->Protocol] (iface, &hdr->Source, dataLength, data);
-	else
+	if( !gaIPv4_Callbacks[hdr->Protocol] ) {
 		Log_Log("IPv4", "Unknown Protocol %i", hdr->Protocol);
+		return ;
+	}
+	
+	gaIPv4_Callbacks[hdr->Protocol]( iface, &hdr->Source, dataLength, data );
 }
 
 /**
  * \fn tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address)
  * \brief Searches an adapter for a matching address
+ * \param Adapter	Incoming Adapter
+ * \param Address	Destination Address
+ * \param Broadcast	Allow broadcast packets
  */
 tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
 {
@@ -170,23 +272,16 @@ tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
 	{
 		if( iface->Adapter != Adapter )	continue;
 		if( iface->Type != 4 )	continue;
-		if( IP4_EQU(Address, iface->IP4.Address) )
+		if( IP4_EQU(Address, *(tIPv4*)iface->Address) )
 			return iface;
 		
 		if( !Broadcast )	continue;
 		
-		this = ntohl( iface->IP4.Address.L );
+		this = ntohl( ((tIPv4*)iface->Address)->L );
 		
 		// Check for broadcast
-		netmask = IPv4_Netmask(iface->IP4.SubnetBits);
+		netmask = IPv4_Netmask(iface->SubnetBits);
 		
-		//Log("netmask = 0x%08x", netmask);
-		//Log("addr = 0x%08x", addr);
-		//Log("this = 0x%08x", this);
-		//Log("%08x == %08x && %08x == %08x",
-		//	(addr & netmask), (this & netmask),
-		//	(addr & ~netmask), (0xFFFFFFFF & ~netmask)
-		//	);
 		if( (addr & netmask) == (this & netmask)
 		 && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
 			return iface;
@@ -196,41 +291,52 @@ tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
 
 /**
  * \brief Convert a network prefix to a netmask
+ * \param FixedBits	Netmask size (/n)
  * 
- * For example /24 will become 255.255.255.0
+ * For example /24 will become 255.255.255.0 (0xFFFFFF00)
  */
 Uint32 IPv4_Netmask(int FixedBits)
 {
 	Uint32	ret = 0xFFFFFFFF;
 	ret >>= (32-FixedBits);
 	ret <<= (32-FixedBits);
-	// Returs a little endian netmask
+	// Returns a native endian netmask
 	return ret;
 }
 
 /**
  * \brief Calculate the IPv4 Checksum
+ * \param Buf	Input buffer
+ * \param Size	Size of input
+ * 
+ * One's complement sum of all 16-bit words (bitwise inverted)
  */
-Uint16 IPv4_Checksum(void *Buf, int Size)
+Uint16 IPv4_Checksum(const void *Buf, int Size)
 {
-	Uint16	sum = 0;
-	Uint16	*arr = Buf;
+	Uint32	sum = 0;
+	const Uint16	*arr = Buf;
 	 int	i;
 	
-	Size = (Size + 1) >> 1;
+	Size = (Size + 1) >> 1;	// 16-bit word count
 	for(i = 0; i < Size; i++ )
 	{
-		if((int)sum + arr[i] > 0xFFFF)
-			sum ++;	// Simulate 1's complement
-		sum += arr[i];
+		Uint16	val = ntohs(arr[i]);
+		sum += val;
 	}
-	return ~sum ;
+	
+	// Apply one's complement
+	while (sum >> 16)
+		sum = (sum & 0xFFFF) + (sum >> 16);
+	
+	return ~sum;
 }
 
 /**
  * \brief Sends an ICMP Echo and waits for a reply
+ * \param IFace	Interface
+ * \param Addr	Destination address
  */
-int IPv4_Ping(tInterface *Iface, tIPv4 Addr)
+int IPv4_Ping(tInterface *IFace, tIPv4 Addr)
 {
-	return ICMP_Ping(Iface, Addr);
+	return ICMP_Ping(IFace, Addr);
 }