Modules/IPStack/icmp.c

   1 /*
   2  * Acess2 IP Stack
   3  * - ICMP Handling
   4  */
   5 #include "ipstack.h"
   6 #include "ipv4.h"
   7 #include "icmp.h"
   8
   9 // === CONSTANTS ===
  10 #define PING_SLOTS      64
  11
  12 // === PROTOTYPES ===
  13 void    ICMP_Initialise();
  14 void    ICMP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer);
  15
  16 // === GLOBALS ===
  17 struct {
  18         tInterface      *Interface;
  19          int    bArrived;
  20 }       gICMP_PingSlots[PING_SLOTS];
  21
  22 // === CODE ===
  23 /**
  24  * \fn void ICMP_Initialise()
  25  * \brief Initialise the ICMP Layer
  26  */
  27 void ICMP_Initialise()
  28 {
  29         IPv4_RegisterCallback(IP4PROT_ICMP, ICMP_GetPacket);
  30 }
  31
  32 /**
  33  * \fn void ICMP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
  34  * \brief Handles a packet from the IP Layer
  35  */
  36 void ICMP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
  37 {
  38         tICMPHeader     *hdr = Buffer;
  39
  40         Log("[ICMP ] Length = %i", Length);
  41         Log("[ICMP ] hdr->Type = %i", hdr->Type);
  42         Log("[ICMP ] hdr->Code = %i", hdr->Code);
  43         Log("[ICMP ] hdr->Checksum = 0x%x", ntohs(hdr->Checksum));
  44         Log("[ICMP ] hdr->ID = 0x%x", ntohs(hdr->ID));
  45         Log("[ICMP ] hdr->Sequence = 0x%x", ntohs(hdr->Sequence));
  46
  47         switch(hdr->Type)
  48         {
  49         // -- 0: Echo Reply
  50         case ICMP_ECHOREPLY:
  51                 if(hdr->Code != 0) {
  52                         Warning("[ICMP ] Code == %i for ICMP Echo Reply, should be 0", hdr->Code);
  53                         return ;
  54                 }
  55                 if(hdr->ID != (Uint16)~hdr->Sequence) {
  56                         Warning("[ICMP ] ID and Sequence values do not match");
  57                         return ;
  58                 }
  59                 gICMP_PingSlots[hdr->ID].bArrived = 1;
  60                 break;
  61
  62         // -- 3: Destination Unreachable
  63         case ICMP_UNREACHABLE:
  64                 switch(hdr->Code)
  65                 {
  66                 case 3: // Port Unreachable
  67                         Log("[ICMP ] Destination Unreachable (Port Unreachable)");
  68                         break;
  69                 default:
  70                         Log("[ICMP ] Destination Unreachable (Code %i)", hdr->Code);
  71                         break;
  72                 }
  73                 break;
  74
  75         // -- 8: Echo Request
  76         case ICMP_ECHOREQ:
  77                 if(hdr->Code != 0) {
  78                         Warning("[ICMP ] Code == %i for ICMP Echo Request, should be 0", hdr->Code);
  79                         return ;
  80                 }
  81                 Log("[ICMP ] Replying");
  82                 hdr->Type = ICMP_ECHOREPLY;
  83                 hdr->Checksum = 0;
  84                 hdr->Checksum = htons( IPv4_Checksum(hdr, Length) );
  85                 Log("[ICMP ] Checksum = 0x%04x", hdr->Checksum);
  86                 IPv4_SendPacket(Interface, *(tIPv4*)Address, 1, ntohs(hdr->Sequence), Length, hdr);
  87                 break;
  88         default:
  89                 break;
  90         }
  91
  92 }
  93
  94 /**
  95  * \brief Sends ICMP Echo and waits for the reply
  96  * \note Times out after \a Interface->TimeoutDelay has elapsed
  97  */
  98 int ICMP_Ping(tInterface *Interface, tIPv4 Addr)
  99 {
 100         Sint64  ts;
 101         Sint64  end;
 102         char    buf[32] = "\x8\0\0\0\0\0\0\0Acess2 I"
 103                       "P/TCP Stack 1.0\0";
 104         tICMPHeader     *hdr = (void*)buf;
 105          int    i;
 106
 107         for(;;)
 108         {
 109                 for(i=0;i<PING_SLOTS;i++)
 110                 {
 111                         if(gICMP_PingSlots[i].Interface == NULL)        break;
 112                 }
 113                 if(gICMP_PingSlots[i].Interface == NULL)        break;
 114                 Threads_Yield();
 115         }
 116         gICMP_PingSlots[i].Interface = Interface;
 117         gICMP_PingSlots[i].bArrived = 0;
 118         hdr->ID = i;
 119         hdr->Sequence = ~i;
 120         hdr->Checksum = htons( IPv4_Checksum(hdr, sizeof(buf)) );
 121         IPv4_SendPacket(Interface, Addr, 1, i, sizeof(buf), buf);
 122
 123         ts = now();
 124         end = ts + Interface->TimeoutDelay;
 125         while( !gICMP_PingSlots[i].bArrived && now() < end)     Threads_Yield();
 126
 127         ts = now() - ts;
 128         if(ts > Interface->TimeoutDelay)
 129                 return -1;
 130
 131         return (int)ts;
 132 }