3 * - IPv4 Protcol Handling
12 #define DEFAULT_TTL 32
13 #define IPV4_TRACE 0 // set to 1 to enable packet tracing
16 extern tInterface *gIP_Interfaces;
17 extern void ICMP_Initialise();
18 extern int ICMP_Ping(tInterface *Interface, tIPv4 Addr);
19 extern tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address);
20 extern void ARP_UpdateCache4(tIPv4 SWAddr, tMacAddr HWAddr);
23 int IPv4_Initialise();
24 int IPv4_RegisterCallback(int ID, tIPCallback Callback);
25 void IPv4_int_GetPacket(tAdapter *Interface, tMacAddr From, int Length, void *Buffer);
26 tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
27 Uint32 IPv4_Netmask(int FixedBits);
28 Uint16 IPv4_Checksum(const void *Buf, size_t Length);
29 int IPv4_Ping(tInterface *Iface, tIPv4 Addr);
32 tIPCallback gaIPv4_Callbacks[256];
36 * \brief Initialise the IPv4 Code
41 Link_RegisterType(IPV4_ETHERNET_ID, IPv4_int_GetPacket);
46 * \brief Registers a callback
47 * \param ID 8-bit packet type ID
48 * \param Callback Callback function
50 int IPv4_RegisterCallback(int ID, tIPCallback Callback)
52 if( ID < 0 || ID > 255 ) return 0;
53 if( gaIPv4_Callbacks[ID] ) return 0;
54 gaIPv4_Callbacks[ID] = Callback;
59 * \brief Creates and sends an IPv4 Packet
60 * \param Iface Interface
61 * \param Address Destination IP
62 * \param Protocol Protocol ID
63 * \param ID Some random ID number
64 * \param Length Data Length
65 * \param Data Packet Data
66 * \return Boolean Success
68 int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, tIPStackBuffer *Buffer)
74 length = IPStack_Buffer_GetLength(Buffer);
76 // --- Resolve destination MAC address
77 to = ARP_Resolve4(Iface, Address);
78 if( MAC_EQU(to, cMAC_ZERO) ) {
80 Log_Notice("IPv4", "No route to host %i.%i.%i.%i",
81 Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
85 // --- Handle OUTPUT firewall rules
86 // TODO: Update firewall rules for tIPStackBuffer
88 int ret = IPTables_TestChain("OUTPUT",
89 4, (tIPv4*)Iface->Address, &Address,
93 // Just drop it (with an error)
94 Log_Notice("IPv4", "Firewall dropped packet");
99 // --- Initialise header
101 hdr.HeaderLength = sizeof(tIPv4Header)/4;
102 hdr.DiffServices = 0; // TODO: Check
105 hdr.DontFragment = 0;
106 hdr.MoreFragments = 0;
110 hdr.TotalLength = htons( sizeof(tIPv4Header) + length );
111 hdr.Identifcation = htons( ID ); // TODO: Check
112 hdr.TTL = DEFAULT_TTL;
113 hdr.Protocol = Protocol;
114 hdr.HeaderChecksum = 0; // Will be set later
115 hdr.Source = *(tIPv4*)Iface->Address;
116 hdr.Destination = Address;
118 // Actually set checksum (zeroed above)
119 hdr.HeaderChecksum = htons( IPv4_Checksum(&hdr, sizeof(tIPv4Header)) );
121 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tIPv4Header), 0, &hdr, NULL, NULL);
124 Log_Log("IPv4", "Sending packet to %i.%i.%i.%i",
125 Address.B[0], Address.B[1], Address.B[2], Address.B[3]);
127 Link_SendPacket(Iface->Adapter, IPV4_ETHERNET_ID, to, Buffer);
132 * \fn void IPv4_int_GetPacket(tInterface *Adapter, tMacAddr From, int Length, void *Buffer)
133 * \brief Process an IPv4 Packet
135 void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
137 tIPv4Header *hdr = Buffer;
143 if(Length < sizeof(tIPv4Header)) return;
146 //Log_Log("IPv4", "Version = %i", hdr->Version);
147 //Log_Log("IPv4", "HeaderLength = %i", hdr->HeaderLength);
148 //Log_Log("IPv4", "DiffServices = %i", hdr->DiffServices);
149 Log_Debug("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) );
150 //Log_Log("IPv4", "Identifcation = %i", ntohs(hdr->Identifcation) );
151 //Log_Log("IPv4", "TTL = %i", hdr->TTL );
152 Log_Debug("IPv4", "Protocol = %i", hdr->Protocol );
153 //Log_Log("IPv4", "HeaderChecksum = 0x%x", ntohs(hdr->HeaderChecksum) );
154 Log_Debug("IPv4", "Source = %i.%i.%i.%i",
155 hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3] );
156 Log_Debug("IPv4", "Destination = %i.%i.%i.%i",
157 hdr->Destination.B[0], hdr->Destination.B[1],
158 hdr->Destination.B[2], hdr->Destination.B[3] );
161 // Check that the version IS IPv4
162 if(hdr->Version != 4) {
163 Log_Log("IPv4", "hdr->Version(%i) != 4", hdr->Version);
167 // Check Header checksum
169 Uint16 hdrVal, compVal;
170 hdrVal = ntohs(hdr->HeaderChecksum);
171 hdr->HeaderChecksum = 0;
172 compVal = IPv4_Checksum(hdr, hdr->HeaderLength * 4);
173 if(hdrVal != compVal) {
174 Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal);
177 hdr->HeaderChecksum = hdrVal;
180 // Check Packet length
181 if( ntohs(hdr->TotalLength) > Length) {
182 Log_Log("IPv4", "hdr->TotalLength(%i) > Length(%i)", ntohs(hdr->TotalLength), Length);
186 // TODO: Handle packet fragmentation
189 Log_Debug("IPv4", " From %i.%i.%i.%i to %i.%i.%i.%i",
190 hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3],
191 hdr->Destination.B[0], hdr->Destination.B[1], hdr->Destination.B[2], hdr->Destination.B[3]
195 // TODO: Should ARP sniffing be used?
196 // - If we get a packet, cache the source MAC
197 ARP_UpdateCache4(hdr->Source, From);
199 // Get Data and Data Length
200 dataLength = ntohs(hdr->TotalLength) - sizeof(tIPv4Header);
201 data = &hdr->Options[0];
203 // Get Interface (allowing broadcasts)
204 iface = IPv4_GetInterface(Adapter, hdr->Destination, 1);
209 ret = IPTables_TestChain("INPUT",
210 4, &hdr->Source, &hdr->Destination,
217 ret = IPTables_TestChain("FORWARD",
218 4, &hdr->Source, &hdr->Destination,
229 Log_Debug("IPv4", "Silently dropping packet");
234 // Unknown, silent drop
236 Log_Warning("IPv4", "Unknown firewall rule");
248 // TODO: Put this in another thread to avoid delays in the RX thread
249 Log_Debug("IPv4", "Route the packet");
250 // Drop the packet if the TTL is zero
251 if( hdr->TTL == 0 ) {
252 Log_Warning("IPv4", "TODO: Send ICMP-Timeout when TTL exceeded");
258 rt = IPStack_FindRoute(4, NULL, &hdr->Destination); // Get the route (gets the interface)
259 if( !rt || !rt->Interface )
261 to = ARP_Resolve4(rt->Interface, hdr->Destination); // Resolve address
262 if( MAC_EQU(to, cMAC_ZERO) )
266 Log_Log("IPv4", "Forwarding packet to %i.%i.%i.%i (via %i.%i.%i.%i)",
267 hdr->Destination.B[0], hdr->Destination.B[1],
268 hdr->Destination.B[2], hdr->Destination.B[3],
269 ((tIPv4*)rt->NextHop)->B[0], ((tIPv4*)rt->NextHop)->B[1],
270 ((tIPv4*)rt->NextHop)->B[2], ((tIPv4*)rt->NextHop)->B[3]);
271 Log_Warning("IPv4", "TODO: Implement forwarding with tIPStackBuffer");
272 // Link_SendPacket(rt->Interface->Adapter, IPV4_ETHERNET_ID, to, Length, Buffer);
279 if( !gaIPv4_Callbacks[hdr->Protocol] ) {
280 Log_Log("IPv4", "Unknown Protocol %i", hdr->Protocol);
284 gaIPv4_Callbacks[hdr->Protocol]( iface, &hdr->Source, dataLength, data );
288 * \fn tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address)
289 * \brief Searches an adapter for a matching address
290 * \param Adapter Incoming Adapter
291 * \param Address Destination Address
292 * \param Broadcast Allow broadcast packets
294 tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast)
296 tInterface *iface = NULL, *zero_iface = NULL;
300 ENTER("pAdapter xAddress bBroadcast", Adapter, Address, Broadcast);
302 addr = ntohl( Address.L );
303 LOG("addr = 0x%x", addr);
305 for( iface = gIP_Interfaces; iface; iface = iface->Next)
307 if( iface->Adapter != Adapter ) continue;
308 if( iface->Type != 4 ) continue;
309 if( IP4_EQU(Address, *(tIPv4*)iface->Address) ) {
315 LOG("iface->Address = 0x%x", *(Uint32*)iface->Address);
317 if( *(Uint32*)iface->Address == 0 ) {
319 Log_Notice("IPv4", "Multiple 0.0.0.0 interfaces on the same adapter, ignoring");
323 LOG("Zero IF %p", iface);
328 if( !Broadcast ) continue;
330 // Check for broadcast
331 this = ntohl( ((tIPv4*)iface->Address)->L );
332 netmask = IPv4_Netmask(iface->SubnetBits);
333 LOG("iface addr = 0x%x, netmask = 0x%x (bits = %i)", this, netmask, iface->SubnetBits);
335 if( (addr & netmask) == (this & netmask) && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) )
337 LOG("Broadcast match");
343 // Special case for intefaces that are being DHCP configured
344 // - If the interface address is 0.0.0.0, then if there is no match for the
345 // destination the packet is treated as if it was addressed to 0.0.0.0
346 if( zero_iface && Broadcast )
348 LOG("Using 0.0.0.0 interface with magic!");
349 LEAVE('p', zero_iface);
358 * \brief Convert a network prefix to a netmask
359 * \param FixedBits Netmask size (/n)
361 * For example /24 will become 255.255.255.0 (0xFFFFFF00)
363 Uint32 IPv4_Netmask(int FixedBits)
365 Uint32 ret = 0xFFFFFFFF;
370 ret >>= (32-FixedBits);
371 ret <<= (32-FixedBits);
373 // Returns a native endian netmask
378 * \brief Calculate the IPv4 Checksum
379 * \param Buf Input buffer
380 * \param Size Size of input
382 * One's complement sum of all 16-bit words (bitwise inverted)
384 Uint16 IPv4_Checksum(const void *Buf, size_t Length)
386 const Uint16 *words = Buf;
390 // Sum all whole words
391 for(i = 0; i < Length/2; i++ )
393 sum += ntohs(words[i]);
396 sum += ntohs( words[i] & 0xFF );
398 // Apply one's complement
400 sum = (sum & 0xFFFF) + (sum >> 16);
406 * \brief Sends an ICMP Echo and waits for a reply
407 * \param IFace Interface
408 * \param Addr Destination address
410 int IPv4_Ping(tInterface *IFace, tIPv4 Addr)
412 return ICMP_Ping(IFace, Addr);