KernelLand/Modules/IPStack/arp.c

   1 /*
   2  * Acess2 IP Stack
   3  * - Address Resolution Protocol
   4  * - Part of the IPv4 protocol
   5  */
   6 #define DEBUG   0
   7 #include "ipstack.h"
   8 #include "arp.h"
   9 #include "link.h"
  10 #include "ipv4.h"       // For IPv4_Netmask
  11 #include "include/adapters_int.h"       // for MAC addr
  12 #include <semaphore.h>
  13 #include <timers.h>
  14 #include "hwaddr_cache.h"
  15
  16 #define ARPv6   0
  17 #define ARP_CACHE_SIZE  128
  18 #define ARP_MAX_AGE             (60*60*1000)    // 1Hr
  19
  20 // === IMPORTS ===
  21 extern tInterface       *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
  22 #if ARPv6
  23 extern tInterface       *IPv6_GetInterface(tAdapter *Adapter, tIPv6 Address, int Broadcast);
  24 #endif
  25
  26 // === PROTOTYPES ===
  27  int    ARP_Initialise();
  28 void    ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer);
  29
  30 // === GLOBALS ===
  31
  32 // === CODE ===
  33 /**
  34  * \fn int ARP_Initialise()
  35  * \brief Initalise the ARP section
  36  */
  37 int ARP_Initialise()
  38 {
  39         Link_RegisterType(0x0806, ARP_int_GetPacket);
  40         return 1;
  41 }
  42
  43 void ARP_Request4(tInterface *Interface, tIPv4 Address)
  44 {
  45         struct sArpRequest4     req;
  46         // Create request
  47         Log_Log("ARP4", "Asking for address %i.%i.%i.%i",
  48                 Address.B[0], Address.B[1], Address.B[2], Address.B[3]
  49                 );
  50         req.HWType = htons(0x0001);     // Ethernet
  51         req.Type   = htons(0x0800);
  52         req.HWSize = 6;
  53         req.SWSize = 4;
  54         req.Request = htons(1);
  55         memcpy(&req.SourceMac, Interface->Adapter->HWAddr, 6);  // TODO: Remove hard size
  56         req.SourceIP = *(tIPv4*)Interface->Address;
  57         req.DestMac = cMAC_BROADCAST;
  58         req.DestIP = Address;
  59
  60         // Assumes only a header and footer at link layer
  61         tIPStackBuffer  *buffer = IPStack_Buffer_CreateBuffer(3);
  62         IPStack_Buffer_AppendSubBuffer(buffer, sizeof(struct sArpRequest4), 0, &req, NULL, NULL);
  63
  64         // Send Request
  65         Link_SendPacket(Interface->Adapter, 0x0806, req.DestMac, buffer);
  66 }
  67
  68 /**
  69  * \fn void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
  70  * \brief Called when an ARP packet is recieved
  71  */
  72 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
  73 {
  74         tArpRequest4    *req4 = Buffer;
  75         #if ARPv6
  76         tArpRequest6    *req6 = Buffer;
  77         #endif
  78         tInterface      *iface;
  79
  80         // Sanity Check Packet
  81         if( Length < (int)sizeof(tArpRequest4) ) {
  82                 Log_Log("ARP", "Recieved undersized packet");
  83                 return ;
  84         }
  85         if( ntohs(req4->Type) != 0x0800 ) {
  86                 Log_Log("ARP", "Recieved a packet with a bad type (0x%x)", ntohs(req4->Type));
  87                 return ;
  88         }
  89         if( req4->HWSize != 6 ) {
  90                 Log_Log("ARP", "Recieved a packet with HWSize != 6 (%i)", req4->HWSize);
  91                 return;
  92         }
  93         #if ARP_DETECT_SPOOFS
  94         if( !MAC_EQU(req4->SourceMac, From) ) {
  95                 Log_Log("ARP", "ARP spoofing detected "
  96                         "(%02x%02x:%02x%02x:%02x%02x != %02x%02x:%02x%02x:%02x%02x)",
  97                         req4->SourceMac.B[0], req4->SourceMac.B[1], req4->SourceMac.B[2],
  98                         req4->SourceMac.B[3], req4->SourceMac.B[4], req4->SourceMac.B[5],
  99                         From.B[0], From.B[1], From.B[2],
 100                         From.B[3], From.B[4], From.B[5]
 101                         );
 102                 return;
 103         }
 104         #endif
 105
 106         switch( ntohs(req4->Request) )
 107         {
 108         case 1: // You want my IP?
 109                 // Check what type of IP it is
 110                 switch( req4->SWSize )
 111                 {
 112                 case 4:
 113                         iface = IPv4_GetInterface(Adapter, req4->DestIP, 0);
 114                         if( iface )
 115                         {
 116                                 Log_Debug("ARP", "ARP Request IPv4 Address %i.%i.%i.%i from %i.%i.%i.%i"
 117                                         " (%02x:%02x:%02x:%02x:%02x:%02x)",
 118                                         req4->DestIP.B[0], req4->DestIP.B[1], req4->DestIP.B[2],
 119                                         req4->DestIP.B[3],
 120                                         req4->SourceIP.B[0], req4->SourceIP.B[1],
 121                                         req4->SourceIP.B[2], req4->SourceIP.B[3],
 122                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 123                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 124                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 125                                 // Someone has ARPed us, let's cache them
 126                                 HWCache_Set(Adapter, 4, &req4->SourceIP, &req4->SourceMac);
 127
 128                                 req4->DestIP = req4->SourceIP;
 129                                 req4->DestMac = req4->SourceMac;
 130                                 req4->SourceIP = *(tIPv4*)iface->Address;;
 131                                 memcpy(&req4->SourceMac, Adapter->HWAddr, 6);   // TODO: Remove hard size
 132                                 req4->Request = htons(2);
 133                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 134                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 135                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 136                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 137
 138                                 // Assumes only a header and footer at link layer
 139                                 tIPStackBuffer  *buffer = IPStack_Buffer_CreateBuffer(3);
 140                                 IPStack_Buffer_AppendSubBuffer(buffer,
 141                                         sizeof(struct sArpRequest4), 0, req4,
 142                                         NULL, NULL);
 143                                 Link_SendPacket(Adapter, 0x0806, req4->DestMac, buffer);
 144                         }
 145                         break;
 146                 #if ARPv6
 147                 case 6:
 148                         if( Length < (int)sizeof(tArpRequest6) ) {
 149                                 Log_Log("ARP", "Recieved undersized packet (IPv6)");
 150                                 return ;
 151                         }
 152                         Log_Debug("ARP", "ARP Request IPv6 Address %08x:%08x:%08x:%08x",
 153                                 ntohl(req6->DestIP.L[0]), ntohl(req6->DestIP.L[1]),
 154                                 ntohl(req6->DestIP.L[2]), ntohl(req6->DestIP.L[3])
 155                                 );
 156                         iface = IPv6_GetInterface(Adapter, req6->DestIP, 0);
 157                         if( iface )
 158                         {
 159                                 req6->DestIP = req6->SourceIP;
 160                                 req6->DestMac = req6->SourceMac;
 161                                 req6->SourceIP = *(tIPv6*)iface->Address;
 162                                 req6->SourceMac = Adapter->MacAddr;
 163                                 req6->Request = htons(2);
 164                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 165                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 166                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 167                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 168                                 Link_SendPacket(Adapter, 0x0806, req6->DestMac, sizeof(tArpRequest6), req6);
 169                         }
 170                         break;
 171                 #endif
 172                 default:
 173                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 174                         return ;
 175                 }
 176
 177                 break;
 178
 179         case 2: // Ooh! A response!
 180                 // Check what type of IP it is
 181                 switch( req4->SWSize )
 182                 {
 183                 case 4:
 184                         HWCache_Set(Adapter, 4, &req4->SourceIP, &From);
 185                         break;
 186                 #if ARPv6
 187                 case 6:
 188                         if( Length < (int)sizeof(tArpRequest6) ) {
 189                                 Log_Debug("ARP", "Recieved undersized packet (IPv6)");
 190                                 return ;
 191                         }
 192                         HWCache_Set(Adapter, 6, &req6->SourceIP, &From );
 193                         break;
 194                 #endif
 195                 default:
 196                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 197                         return ;
 198                 }
 199
 200                 break;
 201
 202         default:
 203                 Log_Warning("ARP", "Unknown Request ID %i", ntohs(req4->Request));
 204                 break;
 205         }
 206 }