X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Modules%2FIPStack%2Fipv4.c;h=e2f18f8b058861c3f1e350c9235fc5a97517d5ff;hb=b0ab9997c3256041087483c0840247821bfa55c8;hp=9723d8d7fb8f4efb040e8b0d5ba9a8c8347db743;hpb=04b368645c34cc3853fc13f93e33ac7878be8479;p=tpg%2Facess2.git

diff --git a/Modules/IPStack/ipv4.c b/Modules/IPStack/ipv4.c
index 9723d8d7..e2f18f8b 100644
--- a/Modules/IPStack/ipv4.c
+++ b/Modules/IPStack/ipv4.c
@@ -5,29 +5,106 @@
 #include "ipstack.h"
 #include "link.h"
 #include "ipv4.h"
+#include "firewall.h"
+
+#define DEFAULT_TTL	32
 
 // === IMPORTS ===
 extern tInterface	*gIP_Interfaces;
+extern void	ICMP_Initialise();
+extern  int	ICMP_Ping(tInterface *Interface, tIPv4 Addr);
+extern tMacAddr	ARP_Resolve4(tInterface *Interface, tIPv4 Address);
 
 // === PROTOTYPES ===
  int	IPv4_Initialise();
+ int	IPv4_RegisterCallback(int ID, tIPCallback Callback);
 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(const void *Buf, int Size);
+ int	IPv4_Ping(tInterface *Iface, tIPv4 Addr);
 
 // === GLOBALS ===
 tIPCallback	gaIPv4_Callbacks[256];
 
 // === CODE ===
 /**
- * \fn int IPv4_Initialise()
+ * \brief Initialise the IPv4 Code
  */
 int IPv4_Initialise()
 {
+	ICMP_Initialise();
 	Link_RegisterType(IPV4_ETHERNET_ID, IPv4_int_GetPacket);
 	return 1;
 }
 
+/**
+ * \brief Registers a callback
+ * \param ID	8-bit packet type ID
+ * \param Callback	Callback function
+ */
+int IPv4_RegisterCallback(int ID, tIPCallback Callback)
+{
+	if( ID < 0 || ID > 255 )	return 0;
+	if( gaIPv4_Callbacks[ID] )	return 0;
+	gaIPv4_Callbacks[ID] = Callback;
+	return 1;
+}
+
+/**
+ * \brief Creates and sends an IPv4 Packet
+ * \param Iface	Interface
+ * \param Address	Destination IP
+ * \param Protocol	Protocol ID
+ * \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, const void *Data)
+{
+	tMacAddr	to = ARP_Resolve4(Iface, Address);
+	 int	bufSize = sizeof(tIPv4Header) + Length;
+	char	buf[bufSize];
+	tIPv4Header	*hdr = (void*)buf;
+	 int	ret;
+	
+	// OUTPUT Firewall rule go here
+	ret = IPTablesV4_TestChain("OUTPUT",
+		&Iface->IP4.Address, &Address,
+		Protocol, 0,
+		Length, Data);
+	if(ret != 0) {
+		// Just drop it (with an error)
+		return 0;
+	}
+	
+	memcpy(&hdr->Options[0], Data, Length);
+	hdr->Version = 4;
+	hdr->HeaderLength = sizeof(tIPv4Header)/4;
+	hdr->DiffServices = 0;	// TODO: Check
+	
+	hdr->Reserved = 0;
+	hdr->DontFragment = 0;
+	hdr->MoreFragments = 0;
+	hdr->FragOffLow = 0;
+	hdr->FragOffHi = 0;
+	
+	hdr->TotalLength = htons( bufSize );
+	hdr->Identifcation = htons( ID );	// TODO: Check
+	hdr->TTL = DEFAULT_TTL;
+	hdr->Protocol = Protocol;
+	hdr->HeaderChecksum = 0;	// Will be set later
+	hdr->Source = Iface->IP4.Address;
+	hdr->Destination = Address;
+	hdr->HeaderChecksum = 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]);
+	Link_SendPacket(Iface->Adapter, IPV4_ETHERNET_ID, to, bufSize, buf);
+	return 1;
+}
+
 /**
  * \fn void IPv4_int_GetPacket(tInterface *Adapter, tMacAddr From, int Length, void *Buffer)
  * \brief Process an IPv4 Packet
@@ -38,39 +115,122 @@ 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_Debug("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) );
+	//Log_Log("IPv4", "Identifcation = %i", ntohs(hdr->Identifcation) );
+	//Log_Log("IPv4", "TTL = %i", hdr->TTL );
+	Log_Debug("IPv4", "Protocol = %i", hdr->Protocol );
+	//Log_Log("IPv4", "HeaderChecksum = 0x%x", ntohs(hdr->HeaderChecksum) );
+	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_Debug("IPv4", "Destination = %i.%i.%i.%i",
+		hdr->Destination.B[0], hdr->Destination.B[1],
+		hdr->Destination.B[2], hdr->Destination.B[3] );
+	#endif	
+
 	// Check that the version IS IPv4
-	if(hdr->Version != 4)	return;
+	if(hdr->Version != 4) {
+		Log_Log("IPv4", "hdr->Version(%i) != 4", hdr->Version);
+		return;
+	}
 	
 	// Check Header checksum
-	//TODO
+	{
+		Uint16	hdrVal, compVal;
+		hdrVal = hdr->HeaderChecksum;
+		hdr->HeaderChecksum = 0;
+		compVal = IPv4_Checksum(hdr, hdr->HeaderLength);
+		if(hdrVal != compVal) {
+			Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal);
+			return ;
+		}
+		hdr->HeaderChecksum = hdrVal;
+	}
 	
 	// Check Packet length
-	if(hdr->TotalLength > Length)	return;
+	if( ntohs(hdr->TotalLength) > Length) {
+		Log_Log("IPv4", "hdr->TotalLength(%i) > Length(%i)", ntohs(hdr->TotalLength), Length);
+		return;
+	}
 	
-	// Get Interface (allowing broadcasts)
-	iface = IPv4_GetInterface(Adapter, hdr->Source, 1);
-	if(!iface)	return;	// Not for us? Well, let's ignore it
+	// TODO: Handle packet fragmentation
 	
-	// Defragment
-	//TODO
 	
-	dataLength = hdr->TotalLength - sizeof(tIPv4Header);
+	// 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 = IPTablesV4_TestChain("INPUT",
+			&hdr->Source, &hdr->Destination,
+			hdr->Protocol, 0,
+			dataLength, data
+			);
+	}
+	else {
+		// Routed packets
+		ret = IPTablesV4_TestChain("FORWARD",
+			&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 ;
+	// Unknown, silent drop
+	default:
+		return ;
+	}
+	
+	// Routing
+	if(!iface)
+	{
+		Log_Debug("IPv4", "Route the packet");
+		
+		// TODO: Parse Routing tables and determine where to send it
+		
+		return ;
+	}
+	
 	// Send it on
-	gaIPv4_Callbacks[hdr->Protocol] (iface, &hdr->Source, dataLength, data);
+	if( gaIPv4_Callbacks[hdr->Protocol] )
+		gaIPv4_Callbacks[hdr->Protocol]( iface, &hdr->Source, dataLength, data );
+	else
+		Log_Log("IPv4", "Unknown Protocol %i", hdr->Protocol);
 }
 
 /**
  * \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)
 {
 	tInterface	*iface = NULL;
 	Uint32	netmask;
+	Uint32	addr, this;
+	
+	addr = ntohl( Address.L );
 	
 	for( iface = gIP_Interfaces; iface; iface = iface->Next)
 	{
@@ -81,10 +241,13 @@ tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
 		
 		if( !Broadcast )	continue;
 		
+		this = ntohl( iface->IP4.Address.L );
+		
 		// Check for broadcast
 		netmask = IPv4_Netmask(iface->IP4.SubnetBits);
-		if( (Address.L & netmask) == (iface->IP4.Address.L & netmask)
-		 && (Address.L & ~netmask) == (0xFFFFFFFF & ~netmask) )
+		
+		if( (addr & netmask) == (this & netmask)
+		 && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
 			return iface;
 	}
 	return NULL;
@@ -92,6 +255,7 @@ 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
  */
@@ -100,5 +264,39 @@ Uint32 IPv4_Netmask(int FixedBits)
 	Uint32	ret = 0xFFFFFFFF;
 	ret >>= (32-FixedBits);
 	ret <<= (32-FixedBits);
+	// 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(const void *Buf, int Size)
+{
+	Uint16	sum = 0;
+	const Uint16	*arr = Buf;
+	 int	i;
+	
+	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];
+	}
+	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)
+{
+	return ICMP_Ping(IFace, Addr);
+}