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         // -- 8: Echo Request
  63         case ICMP_ECHOREQ:
  64                 if(hdr->Code != 0) {
  65                         Warning("[ICMP ] Code == %i for ICMP Echo Request, should be 0", hdr->Code);
  66                         return ;
  67                 }
  68                 Log("[ICMP ] Replying");
  69                 hdr->Type = ICMP_ECHOREPLY;
  70                 hdr->Checksum = 0;
  71                 hdr->Checksum = htons( IPv4_Checksum(hdr, Length) );
  72                 Log("[ICMP ] Checksum = 0x%04x", hdr->Checksum);
  73                 IPv4_SendPacket(Interface, *(tIPv4*)Address, 1, ntohs(hdr->Sequence), Length, hdr);
  74                 break;
  75         }
  76
  77 }
  78
  79 /**
  80  * \brief Sends ICMP Echo and waits for the reply
  81  * \note Times out after \a Interface->TimeoutDelay has elapsed
  82  */
  83 int ICMP_Ping(tInterface *Interface, tIPv4 Addr)
  84 {
  85         Sint64  ts;
  86         Sint64  end;
  87         char    buf[32] = "\x8\0\0\0\0\0\0\0Acess2 I"
  88                       "P/TCP Stack 1.0\0";
  89         tICMPHeader     *hdr = (void*)buf;
  90          int    i;
  91
  92         for(;;)
  93         {
  94                 for(i=0;i<PING_SLOTS;i++)
  95                 {
  96                         if(gICMP_PingSlots[i].Interface == NULL)        break;
  97                 }
  98                 if(gICMP_PingSlots[i].Interface == NULL)        break;
  99                 Threads_Yield();
 100         }
 101         gICMP_PingSlots[i].Interface = Interface;
 102         gICMP_PingSlots[i].bArrived = 0;
 103         hdr->ID = i;
 104         hdr->Sequence = ~i;
 105         hdr->Checksum = htons( IPv4_Checksum(hdr, sizeof(buf)) );
 106         IPv4_SendPacket(Interface, Addr, 1, i, sizeof(buf), buf);
 107
 108         ts = now();
 109         end = ts + Interface->TimeoutDelay;
 110         while( !gICMP_PingSlots[i].bArrived && now() < end)     Threads_Yield();
 111
 112         ts = now() - ts;
 113         if(ts > Interface->TimeoutDelay)
 114                 return -1;
 115
 116         return (int)ts;
 117 }