3 * - IPv4 Protcol Handling
11 #define DEFAULT_TTL 32
14 extern tInterface *gIP_Interfaces;
15 extern void ICMP_Initialise();
16 extern int ICMP_Ping(tInterface *Interface, tIPv4 Addr);
17 extern tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address);
18 extern void ARP_UpdateCache4(tIPv4 SWAddr, tMacAddr HWAddr);
21 int IPv4_Initialise();
22 int IPv4_RegisterCallback(int ID, tIPCallback Callback);
23 void IPv4_int_GetPacket(tAdapter *Interface, tMacAddr From, int Length, void *Buffer);
24 tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
25 Uint32 IPv4_Netmask(int FixedBits);
26 Uint16 IPv4_Checksum(const void *Buf, size_t Length);
27 int IPv4_Ping(tInterface *Iface, tIPv4 Addr);
30 tIPCallback gaIPv4_Callbacks[256];
34 * \brief Initialise the IPv4 Code
39 Link_RegisterType(IPV4_ETHERNET_ID, IPv4_int_GetPacket);
44 * \brief Registers a callback
45 * \param ID 8-bit packet type ID
46 * \param Callback Callback function
48 int IPv4_RegisterCallback(int ID, tIPCallback Callback)
50 if( ID < 0 || ID > 255 ) return 0;
51 if( gaIPv4_Callbacks[ID] ) return 0;
52 gaIPv4_Callbacks[ID] = Callback;
57 * \brief Creates and sends an IPv4 Packet
58 * \param Iface Interface
59 * \param Address Destination IP
60 * \param Protocol Protocol ID
61 * \param ID Some random ID number
62 * \param Length Data Length
63 * \param Data Packet Data
64 * \return Boolean Success
66 int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, tIPStackBuffer *Buffer)
72 length = IPStack_Buffer_GetLength(Buffer);
74 // --- Resolve destination MAC address
75 to = ARP_Resolve4(Iface, Address);
76 if( MAC_EQU(to, cMAC_ZERO) ) {
78 Log_Notice("IPv4", "No route to host %i.%i.%i.%i",
79 Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
83 // --- Handle OUTPUT firewall rules
84 // TODO: Update firewall rules for tIPStackBuffer
86 int ret = IPTables_TestChain("OUTPUT",
87 4, (tIPv4*)Iface->Address, &Address,
91 // Just drop it (with an error)
92 Log_Notice("IPv4", "Firewall dropped packet");
97 // --- Initialise header
99 hdr.HeaderLength = sizeof(tIPv4Header)/4;
100 hdr.DiffServices = 0; // TODO: Check
103 hdr.DontFragment = 0;
104 hdr.MoreFragments = 0;
108 hdr.TotalLength = htons( sizeof(tIPv4Header) + length );
109 hdr.Identifcation = htons( ID ); // TODO: Check
110 hdr.TTL = DEFAULT_TTL;
111 hdr.Protocol = Protocol;
112 hdr.HeaderChecksum = 0; // Will be set later
113 hdr.Source = *(tIPv4*)Iface->Address;
114 hdr.Destination = Address;
116 // Actually set checksum (zeroed above)
117 hdr.HeaderChecksum = htons( IPv4_Checksum(&hdr, sizeof(tIPv4Header)) );
119 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tIPv4Header), 0, &hdr, NULL, NULL);
121 Log_Log("IPv4", "Sending packet to %i.%i.%i.%i",
122 Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
123 Link_SendPacket(Iface->Adapter, IPV4_ETHERNET_ID, to, Buffer);
128 * \fn void IPv4_int_GetPacket(tInterface *Adapter, tMacAddr From, int Length, void *Buffer)
129 * \brief Process an IPv4 Packet
131 void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
133 tIPv4Header *hdr = Buffer;
139 if(Length < sizeof(tIPv4Header)) return;
142 //Log_Log("IPv4", "Version = %i", hdr->Version);
143 //Log_Log("IPv4", "HeaderLength = %i", hdr->HeaderLength);
144 //Log_Log("IPv4", "DiffServices = %i", hdr->DiffServices);
145 Log_Debug("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) );
146 //Log_Log("IPv4", "Identifcation = %i", ntohs(hdr->Identifcation) );
147 //Log_Log("IPv4", "TTL = %i", hdr->TTL );
148 Log_Debug("IPv4", "Protocol = %i", hdr->Protocol );
149 //Log_Log("IPv4", "HeaderChecksum = 0x%x", ntohs(hdr->HeaderChecksum) );
150 Log_Debug("IPv4", "Source = %i.%i.%i.%i",
151 hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3] );
152 Log_Debug("IPv4", "Destination = %i.%i.%i.%i",
153 hdr->Destination.B[0], hdr->Destination.B[1],
154 hdr->Destination.B[2], hdr->Destination.B[3] );
157 // Check that the version IS IPv4
158 if(hdr->Version != 4) {
159 Log_Log("IPv4", "hdr->Version(%i) != 4", hdr->Version);
163 // Check Header checksum
165 Uint16 hdrVal, compVal;
166 hdrVal = ntohs(hdr->HeaderChecksum);
167 hdr->HeaderChecksum = 0;
168 compVal = IPv4_Checksum(hdr, hdr->HeaderLength * 4);
169 if(hdrVal != compVal) {
170 Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal);
173 hdr->HeaderChecksum = hdrVal;
176 // Check Packet length
177 if( ntohs(hdr->TotalLength) > Length) {
178 Log_Log("IPv4", "hdr->TotalLength(%i) > Length(%i)", ntohs(hdr->TotalLength), Length);
182 // TODO: Handle packet fragmentation
184 Log_Debug("IPv4", " From %i.%i.%i.%i to %i.%i.%i.%i",
185 hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3],
186 hdr->Destination.B[0], hdr->Destination.B[1], hdr->Destination.B[2], hdr->Destination.B[3]
190 ARP_UpdateCache4(hdr->Source, From);
192 // Get Data and Data Length
193 dataLength = ntohs(hdr->TotalLength) - sizeof(tIPv4Header);
194 data = &hdr->Options[0];
196 // Get Interface (allowing broadcasts)
197 iface = IPv4_GetInterface(Adapter, hdr->Destination, 1);
202 ret = IPTables_TestChain("INPUT",
203 4, &hdr->Source, &hdr->Destination,
210 ret = IPTables_TestChain("FORWARD",
211 4, &hdr->Source, &hdr->Destination,
222 Log_Debug("IPv4", "Silently dropping packet");
227 // Unknown, silent drop
229 Log_Warning("IPv4", "Unknown firewall rule");
241 // TODO: Put this in another thread to avoid delays in the RX thread
242 Log_Debug("IPv4", "Route the packet");
243 // Drop the packet if the TTL is zero
244 if( hdr->TTL == 0 ) {
245 Log_Warning("IPv4", "TODO: Send ICMP-Timeout when TTL exceeded");
251 rt = IPStack_FindRoute(4, NULL, &hdr->Destination); // Get the route (gets the interface)
252 if( !rt || !rt->Interface )
254 to = ARP_Resolve4(rt->Interface, hdr->Destination); // Resolve address
255 if( MAC_EQU(to, cMAC_ZERO) )
259 Log_Log("IPv4", "Forwarding packet to %i.%i.%i.%i (via %i.%i.%i.%i)",
260 hdr->Destination.B[0], hdr->Destination.B[1],
261 hdr->Destination.B[2], hdr->Destination.B[3],
262 ((tIPv4*)rt->NextHop)->B[0], ((tIPv4*)rt->NextHop)->B[1],
263 ((tIPv4*)rt->NextHop)->B[2], ((tIPv4*)rt->NextHop)->B[3]);
264 Log_Warning("IPv4", "TODO: Implement forwarding with tIPStackBuffer");
265 // Link_SendPacket(rt->Interface->Adapter, IPV4_ETHERNET_ID, to, Length, Buffer);
272 if( !gaIPv4_Callbacks[hdr->Protocol] ) {
273 Log_Log("IPv4", "Unknown Protocol %i", hdr->Protocol);
277 gaIPv4_Callbacks[hdr->Protocol]( iface, &hdr->Source, dataLength, data );
281 * \fn tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address)
282 * \brief Searches an adapter for a matching address
283 * \param Adapter Incoming Adapter
284 * \param Address Destination Address
285 * \param Broadcast Allow broadcast packets
287 tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
289 tInterface *iface = NULL, *zero_iface = NULL;
293 ENTER("pAdapter xAddress bBroadcast", Adapter, Address, Broadcast);
295 addr = ntohl( Address.L );
296 LOG("addr = 0x%x", addr);
298 for( iface = gIP_Interfaces; iface; iface = iface->Next)
300 if( iface->Adapter != Adapter ) continue;
301 if( iface->Type != 4 ) continue;
302 if( IP4_EQU(Address, *(tIPv4*)iface->Address) ) {
308 LOG("iface->Address = 0x%x", *(Uint32*)iface->Address);
310 if( *(Uint32*)iface->Address == 0 ) {
312 Log_Notice("IPv4", "Multiple 0.0.0.0 interfaces on the same adapter, ignoring");
316 LOG("Zero IF %p", iface);
321 if( !Broadcast ) continue;
323 // Check for broadcast
324 this = ntohl( ((tIPv4*)iface->Address)->L );
325 netmask = IPv4_Netmask(iface->SubnetBits);
326 LOG("iface addr = 0x%x, netmask = 0x%x (bits = %i)", this, netmask, iface->SubnetBits);
328 if( (addr & netmask) == (this & netmask) && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
330 LOG("Broadcast match");
336 // Special case for intefaces that are being DHCP configured
337 // - If the interface address is 0.0.0.0, then if there is no match for the
338 // destination the packet is treated as if it was addressed to 0.0.0.0
339 if( zero_iface && Broadcast )
341 LOG("Using 0.0.0.0 interface with magic!");
342 LEAVE('p', zero_iface);
351 * \brief Convert a network prefix to a netmask
352 * \param FixedBits Netmask size (/n)
354 * For example /24 will become 255.255.255.0 (0xFFFFFF00)
356 Uint32 IPv4_Netmask(int FixedBits)
358 Uint32 ret = 0xFFFFFFFF;
363 ret >>= (32-FixedBits);
364 ret <<= (32-FixedBits);
366 // Returns a native endian netmask
371 * \brief Calculate the IPv4 Checksum
372 * \param Buf Input buffer
373 * \param Size Size of input
375 * One's complement sum of all 16-bit words (bitwise inverted)
377 Uint16 IPv4_Checksum(const void *Buf, size_t Length)
379 const Uint16 *words = Buf;
383 // Sum all whole words
384 for(i = 0; i < Length/2; i++ )
386 sum += ntohs(words[i]);
389 sum += ntohs( words[i] & 0xFF );
391 // Apply one's complement
393 sum = (sum & 0xFFFF) + (sum >> 16);
399 * \brief Sends an ICMP Echo and waits for a reply
400 * \param IFace Interface
401 * \param Addr Destination address
403 int IPv4_Ping(tInterface *IFace, tIPv4 Addr)
405 return ICMP_Ping(IFace, Addr);