3 * - Address Resolution Protocol
4 * - Part of the IPv4 protocol
12 #define ARP_CACHE_SIZE 64
13 #define ARP_MAX_AGE (60*60*1000) // 1Hr
16 extern tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
18 extern tInterface *IPv6_GetInterface(tAdapter *Adapter, tIPv6 Address, int Broadcast);
23 tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address);
24 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer);
33 int giARP_Cache4Space;
42 int giARP_Cache6Space;
45 int giARP_LastUpdateID = 0;
49 * \fn int ARP_Initialise()
50 * \brief Initalise the ARP section
54 gaARP_Cache4 = malloc( ARP_CACHE_SIZE * sizeof(struct sARP_Cache4) );
55 memset( gaARP_Cache4, 0, ARP_CACHE_SIZE * sizeof(struct sARP_Cache4) );
56 giARP_Cache4Space = ARP_CACHE_SIZE;
59 gaARP_Cache6 = malloc( ARP_CACHE_SIZE * sizeof(struct sARP_Cache6) );
60 memset( gaARP_Cache6, 0, ARP_CACHE_SIZE * sizeof(struct sARP_Cache6) );
61 giARP_Cache6Space = ARP_CACHE_SIZE;
64 Link_RegisterType(0x0806, ARP_int_GetPacket);
69 * \brief Resolves a MAC address from an IPv4 address
71 tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address)
75 struct sArpRequest4 req;
77 ENTER("pInterface xAddress", Interface, Address);
79 // Check routing tables
81 tRoute *route = IPStack_FindRoute(4, Interface, &Address);
83 // If the next hop is defined, use it
84 // - 0.0.0.0 as the next hop means "no next hop / direct"
85 if( ((tIPv4*)route->NextHop)->L != 0 ) {
86 // Recursion: see /Recursion/
87 return ARP_Resolve4(Interface, *(tIPv4*)route->NextHop);
93 Mutex_Acquire( &glARP_Cache4 );
94 for( i = 0; i < giARP_Cache4Space; i++ )
96 if(gaARP_Cache4[i].IP.L != Address.L) continue;
98 // Check if the entry needs to be refreshed
99 if( now() - gaARP_Cache4[i].LastUpdate > ARP_MAX_AGE ) break;
101 Mutex_Release( &glARP_Cache4 );
102 LOG("Return %x:%x:%x:%x:%x:%x",
103 gaARP_Cache4[i].MAC.B[0], gaARP_Cache4[i].MAC.B[1],
104 gaARP_Cache4[i].MAC.B[2], gaARP_Cache4[i].MAC.B[3],
105 gaARP_Cache4[i].MAC.B[4], gaARP_Cache4[i].MAC.B[5]
108 return gaARP_Cache4[i].MAC;
110 Mutex_Release( &glARP_Cache4 );
112 lastID = giARP_LastUpdateID;
115 Log_Log("ARP4", "Asking for address %i.%i.%i.%i",
116 Address.B[0], Address.B[1], Address.B[2], Address.B[3]
118 req.HWType = htons(0x0001); // Ethernet
119 req.Type = htons(0x0800);
122 req.Request = htons(1);
123 req.SourceMac = Interface->Adapter->MacAddr;
124 req.SourceIP = *(tIPv4*)Interface->Address;
125 req.DestMac = cMAC_BROADCAST;
126 req.DestIP = Address;
129 Link_SendPacket(Interface->Adapter, 0x0806, req.DestMac, sizeof(struct sArpRequest4), &req);
134 while(lastID == giARP_LastUpdateID) Threads_Yield();
135 lastID = giARP_LastUpdateID;
137 Mutex_Acquire( &glARP_Cache4 );
138 for( i = 0; i < giARP_Cache4Space; i++ )
140 if(gaARP_Cache4[i].IP.L != Address.L) continue;
142 Mutex_Release( &glARP_Cache4 );
143 return gaARP_Cache4[i].MAC;
145 Mutex_Release( &glARP_Cache4 );
150 * \brief Updates the ARP Cache entry for an IPv4 Address
152 void ARP_UpdateCache4(tIPv4 SWAddr, tMacAddr HWAddr)
158 // Find an entry for the IP address in the cache
159 Mutex_Acquire(&glARP_Cache4);
160 for( i = giARP_Cache4Space; i--; )
162 if(gaARP_Cache4[oldest].LastUpdate > gaARP_Cache4[i].LastUpdate) {
165 if( gaARP_Cache4[i].IP.L == SWAddr.L ) break;
166 if( gaARP_Cache4[i].LastUpdate == 0 && free == -1 ) free = i;
168 // If there was no match, we need to make one
174 gaARP_Cache4[i].IP = SWAddr;
177 Log_Log("ARP4", "Caching %i.%i.%i.%i (%02x:%02x:%02x:%02x:%02x:%02x) in %i",
178 SWAddr.B[0], SWAddr.B[1], SWAddr.B[2], SWAddr.B[3],
179 HWAddr.B[0], HWAddr.B[1], HWAddr.B[2], HWAddr.B[3], HWAddr.B[4], HWAddr.B[5],
183 gaARP_Cache4[i].MAC = HWAddr;
184 gaARP_Cache4[i].LastUpdate = now();
185 giARP_LastUpdateID ++;
186 Mutex_Release(&glARP_Cache4);
191 * \brief Updates the ARP Cache entry for an IPv6 Address
193 void ARP_UpdateCache6(tIPv6 SWAddr, tMacAddr HWAddr)
199 // Find an entry for the MAC address in the cache
200 Mutex_Acquire(&glARP_Cache6);
201 for( i = giARP_Cache6Space; i--; )
203 if(gaARP_Cache6[oldest].LastUpdate > gaARP_Cache6[i].LastUpdate) {
206 if( MAC_EQU(gaARP_Cache6[i].MAC, HWAddr) ) break;
207 if( gaARP_Cache6[i].LastUpdate == 0 && free == -1 ) free = i;
209 // If there was no match, we need to make one
215 gaARP_Cache6[i].MAC = HWAddr;
218 gaARP_Cache6[i].IP = SWAddr;
219 gaARP_Cache6[i].LastUpdate = now();
220 giARP_LastUpdateID ++;
221 Mutex_Release(&glARP_Cache6);
226 * \fn void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
227 * \brief Called when an ARP packet is recieved
229 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
231 tArpRequest4 *req4 = Buffer;
233 tArpRequest6 *req6 = Buffer;
237 // Sanity Check Packet
238 if( Length < (int)sizeof(tArpRequest4) ) {
239 Log_Log("ARP", "Recieved undersized packet");
242 if( ntohs(req4->Type) != 0x0800 ) {
243 Log_Log("ARP", "Recieved a packet with a bad type (0x%x)", ntohs(req4->Type));
246 if( req4->HWSize != 6 ) {
247 Log_Log("ARP", "Recieved a packet with HWSize != 6 (%i)", req4->HWSize);
250 #if ARP_DETECT_SPOOFS
251 if( !MAC_EQU(req4->SourceMac, From) ) {
252 Log_Log("ARP", "ARP spoofing detected "
253 "(%02x%02x:%02x%02x:%02x%02x != %02x%02x:%02x%02x:%02x%02x)",
254 req4->SourceMac.B[0], req4->SourceMac.B[1], req4->SourceMac.B[2],
255 req4->SourceMac.B[3], req4->SourceMac.B[4], req4->SourceMac.B[5],
256 From.B[0], From.B[1], From.B[2],
257 From.B[3], From.B[4], From.B[5]
263 Log_Debug("ARP", "Request ID %i", ntohs(req4->Request));
265 switch( ntohs(req4->Request) )
267 case 1: // You want my IP?
268 Log_Debug("ARP", "ARP Request Address class %i", req4->SWSize);
269 // Check what type of IP it is
270 switch( req4->SWSize )
273 Log_Debug("ARP", "From MAC %02x:%02x:%02x:%02x:%02x:%02x",
274 req4->SourceMac.B[0], req4->SourceMac.B[1],
275 req4->SourceMac.B[2], req4->SourceMac.B[3],
276 req4->SourceMac.B[4], req4->SourceMac.B[5]);
277 //Log_Debug("ARP", "to MAC %02x:%02x:%02x:%02x:%02x:%02x",
278 // req4->DestMac.B[0], req4->DestMac.B[1],
279 // req4->DestMac.B[2], req4->DestMac.B[3],
280 // req4->DestMac.B[4], req4->DestMac.B[5]);
281 Log_Debug("ARP", "ARP Request IPv4 Address %i.%i.%i.%i from %i.%i.%i.%i",
282 req4->DestIP.B[0], req4->DestIP.B[1], req4->DestIP.B[2],
284 req4->SourceIP.B[0], req4->SourceIP.B[1],
285 req4->SourceIP.B[2], req4->SourceIP.B[3]);
286 iface = IPv4_GetInterface(Adapter, req4->DestIP, 0);
289 Log_Debug("ARP", "Caching sender's IP Address");
290 ARP_UpdateCache4(req4->SourceIP, req4->SourceMac);
292 req4->DestIP = req4->SourceIP;
293 req4->DestMac = req4->SourceMac;
294 req4->SourceIP = *(tIPv4*)iface->Address;;
295 req4->SourceMac = Adapter->MacAddr;
296 req4->Request = htons(2);
297 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
298 req4->SourceMac.B[0], req4->SourceMac.B[1],
299 req4->SourceMac.B[2], req4->SourceMac.B[3],
300 req4->SourceMac.B[4], req4->SourceMac.B[5]);
301 Link_SendPacket(Adapter, 0x0806, req4->DestMac, sizeof(tArpRequest4), req4);
306 if( Length < (int)sizeof(tArpRequest6) ) {
307 Log_Log("ARP", "Recieved undersized packet (IPv6)");
310 Log_Debug("ARP", "ARP Request IPv6 Address %08x:%08x:%08x:%08x",
311 ntohl(req6->DestIP.L[0]), ntohl(req6->DestIP.L[1]),
312 ntohl(req6->DestIP.L[2]), ntohl(req6->DestIP.L[3])
314 iface = IPv6_GetInterface(Adapter, req6->DestIP, 0);
317 req6->DestIP = req6->SourceIP;
318 req6->DestMac = req6->SourceMac;
319 req6->SourceIP = *(tIPv6*)iface->Address;
320 req6->SourceMac = Adapter->MacAddr;
321 req6->Request = htons(2);
322 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
323 req4->SourceMac.B[0], req4->SourceMac.B[1],
324 req4->SourceMac.B[2], req4->SourceMac.B[3],
325 req4->SourceMac.B[4], req4->SourceMac.B[5]);
326 Link_SendPacket(Adapter, 0x0806, req6->DestMac, sizeof(tArpRequest6), req6);
331 Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
337 case 2: // Ooh! A response!
338 // Check what type of IP it is
339 switch( req4->SWSize )
342 ARP_UpdateCache4( req4->SourceIP, From );
346 if( Length < (int)sizeof(tArpRequest6) ) {
347 Log_Debug("ARP", "Recieved undersized packet (IPv6)");
350 ARP_UpdateCache6( req6->SourceIP, From );
354 Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
361 Log_Warning("ARP", "Unknown Request ID %i", ntohs(req4->Request));