* Acess2 IP Stack
* - IPv4 Protcol Handling
*/
+#define DEBUG 1
#include "ipstack.h"
#include "link.h"
#include "ipv4.h"
+#include "firewall.h"
#define DEFAULT_TTL 32
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, size_t Length);
int IPv4_Ping(tInterface *Iface, tIPv4 Addr);
// === GLOBALS ===
// === CODE ===
/**
- * \fn int IPv4_Initialise()
+ * \brief Initialise the IPv4 Code
*/
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)
{
* \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);
+ tMacAddr to;
int bufSize = sizeof(tIPv4Header) + Length;
char buf[bufSize];
tIPv4Header *hdr = (void*)buf;
+ int ret;
+
+ to = ARP_Resolve4(Iface, Address);
+ 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;
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]);
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
+
// Check that the version IS IPv4
if(hdr->Version != 4) {
Log_Log("IPv4", "hdr->Version(%i) != 4", hdr->Version);
}
// 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) {
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
+ Log_Debug("IPv4", " From %i.%i.%i.%i to %i.%i.%i.%i",
+ hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3],
+ hdr->Destination.B[0], hdr->Destination.B[1], hdr->Destination.B[2], hdr->Destination.B[3]
+ );
+ // 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: Send ICMP-Timeout when TTL exceeded");
+ return ;
+ }
+
+ hdr->TTL --;
+
+ rt = IPStack_FindRoute(4, NULL, &hdr->Destination); // Get the route (gets the interface)
+ if( !rt || !rt->Interface )
+ return ;
+ 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)
{
tInterface *iface = NULL;
Uint32 netmask;
Uint32 addr, this;
-
+
+ ENTER("pAdapter xAddress bBroadcast", Adapter, Address, Broadcast);
+
addr = ntohl( Address.L );
+ LOG("addr = 0x%x", addr);
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) ) {
+ LOG("Exact match");
+ LEAVE('p', iface);
return iface;
+ }
if( !Broadcast ) continue;
- this = ntohl( iface->IP4.Address.L );
-
// Check for broadcast
- netmask = IPv4_Netmask(iface->IP4.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) )
+ this = ntohl( ((tIPv4*)iface->Address)->L );
+ netmask = IPv4_Netmask(iface->SubnetBits);
+ LOG("iface addr = 0x%x, netmask = 0x%x (bits = %i)", this, netmask, iface->SubnetBits);
+
+ if( (addr & netmask) == (this & netmask) && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
+ {
+ LOG("Broadcast match");
+ LEAVE('p', iface);
return iface;
+ }
}
+ LEAVE('n');
return NULL;
}
/**
* \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
+ if( FixedBits == 0 )
+ return 0;
+ if( FixedBits < 32 )
+ {
+ 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(void *Buf, int Size)
+Uint16 IPv4_Checksum(const void *Buf, size_t Length)
{
- Uint16 sum = 0;
- Uint16 *arr = Buf;
+ const Uint16 *words = Buf;
+ Uint32 sum = 0;
int i;
- Log("IPv4_Checksum: (%p, %i)", Buf, Size);
-
- Size = (Size + 1) >> 1;
- for(i = 0; i < Size; i++ )
+ // Sum all whole words
+ for(i = 0; i < Length/2; i++ )
{
- if((int)sum + arr[i] > 0xFFFF)
- sum ++; // Simulate 1's complement
- sum += arr[i];
+ sum += ntohs(words[i]);
}
- return ~sum ;
+ if( Length & 1 )
+ sum += ntohs( words[i] & 0xFF );
+
+ // 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);
}
git.ucc.asn.au / tpg / acess2.git / blobdiff
UCC git Repository :: git.ucc.asn.au