IPStack - Fixed TCP checksuming

[tpg/acess2.git] / Modules / IPStack / ipv4.c

diff --git a/Modules/IPStack/ipv4.c b/Modules/IPStack/ipv4.c
index ad6c891..6c387cc 100644 (file)
--- a/Modules/IPStack/ipv4.c
+++ b/Modules/IPStack/ipv4.c
@@ -64,23 +64,26 @@ int IPv4_RegisterCallback(int ID, tIPCallback Callback)
 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) ) {
+       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 = IPTablesV4_TestChain("OUTPUT",
-               (tIPv4*)Iface->Address, &Address,
+       ret = IPTables_TestChain("OUTPUT",
+               4, (tIPv4*)Iface->Address, &Address,
                Protocol, 0,
                Length, Data);
-       if(ret != 0) {
+       if(ret > 0) {
                // Just drop it (with an error)
+               Log_Notice("IPv4", "Firewall dropped packet");
                return 0;
        }
        
@@ -102,7 +105,7 @@ int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, int
        hdr->HeaderChecksum = 0;        // Will be set later
        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]);
@@ -121,7 +124,7 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
        Uint8   *data;
         int    dataLength;
         int    ret;
-        
+       
        if(Length < sizeof(tIPv4Header))        return;
        
        #if 0
@@ -149,9 +152,9 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
        // Check Header checksum
        {
                Uint16  hdrVal, compVal;
-               hdrVal = hdr->HeaderChecksum;
+               hdrVal = ntohs(hdr->HeaderChecksum);
                hdr->HeaderChecksum = 0;
-               compVal = IPv4_Checksum(hdr, hdr->HeaderLength);
+               compVal = IPv4_Checksum(hdr, hdr->HeaderLength * 4);
                if(hdrVal != compVal) {
                        Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal);
                        return ;
@@ -178,16 +181,16 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
        // Firewall rules
        if( iface ) {
                // Incoming Packets
-               ret = IPTablesV4_TestChain("INPUT",
-                       &hdr->Source, &hdr->Destination,
+               ret = IPTables_TestChain("INPUT",
+                       4, &hdr->Source, &hdr->Destination,
                        hdr->Protocol, 0,
                        dataLength, data
                        );
        }
        else {
                // Routed packets
-               ret = IPTablesV4_TestChain("FORWARD",
-                       &hdr->Source, &hdr->Destination,
+               ret = IPTables_TestChain("FORWARD",
+                       4, &hdr->Source, &hdr->Destination,
                        hdr->Protocol, 0,
                        dataLength, data
                        );
@@ -200,26 +203,54 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff
        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);
                
-               // TODO: Parse Routing tables and determine where to send it
                
                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 );
 }
 
 /**
@@ -262,7 +293,7 @@ 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
+ * For example /24 will become 255.255.255.0 (0xFFFFFF00)
  */
 Uint32 IPv4_Netmask(int FixedBits)
 {
@@ -282,19 +313,25 @@ Uint32 IPv4_Netmask(int FixedBits)
  */
 Uint16 IPv4_Checksum(const void *Buf, int Size)
 {
-       Uint16  sum = 0;
+       Uint32  sum = 0;
        const Uint16    *arr = Buf;
         int    i;
        
-       Size = (Size + 1) >> 1; // 16-bit word count
-       for(i = 0; i < Size; i++ )
+       // Sum all whole words
+       for(i = 0; i < Size/2; i++ )
        {
                Uint16  val = ntohs(arr[i]);
-               if((int)sum + val > 0xFFFF)
-                       sum ++; // Simulate 1's complement
                sum += val;
        }
-       return ~sum ;
+       // Add the tail word
+//     if( i*2 != Size )
+//             sum += arr[i]&0xFF;
+       
+       // Apply one's complement
+       while (sum >> 16)
+               sum = (sum & 0xFFFF) + (sum >> 16);
+       
+       return ~sum;
 }
 
 /**