#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);
+ const tMacAddr zero = {{0,0,0,0,0,0}};
+ int bufSize = sizeof(tIPv4Header) + Length;
+ char buf[bufSize];
+ tIPv4Header *hdr = (void*)buf;
+ int ret;
+
+ if( MAC_EQU(to, zero) ) {
+ return 0;
+ }
+
+ // OUTPUT Firewall rule go here
+ ret = IPTablesV4_TestChain("OUTPUT",
+ (tIPv4*)Iface->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 = *(tIPv4*)Iface->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
{
tIPv4Header *hdr = Buffer;
tInterface *iface;
- char *data;
+ 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;
- for( iface = Adapter->Interfaces; iface; iface = iface->Next)
+ addr = ntohl( Address.L );
+
+ for( iface = gIP_Interfaces; iface; iface = iface->Next)
{
+ 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( ((tIPv4*)iface->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) )
+ netmask = IPv4_Netmask(iface->SubnetBits);
+
+ if( (addr & netmask) == (this & netmask)
+ && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
return iface;
}
return NULL;
/**
* \brief Convert a network prefix to a netmask
+ * \param FixedBits Netmask size (/n)
*
* For example /24 will become 255.255.255.0
*/
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++ )
+ {
+ Uint16 val = ntohs(arr[i]);
+ if((int)sum + val > 0xFFFF)
+ sum ++; // Simulate 1's complement
+ sum += val;
+ }
+ 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);
+}
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