decoders/decode_icmp.c

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#include "decode_icmp.h"
#include "decode_ip.h"
#include "../packets/packet.h"
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>

//#define DEBUG

extern GlobalVars       Globals;

int     IPDecoderID;

/***************************************
* Apply the icmp decoding
****************************************/
void* DecodeICMP(int PacketSlot){
        ICMPData*               data;
        IPData*                 ip_data;
        unsigned char   ip_proto;
        PacketRec*              p;
        
        DEBUGPATH;

#ifdef DEBUG
        printf("Decoding ICMP Header\n");
#endif

        p=&Globals.Packets[PacketSlot];

        if (!GetDataByID(PacketSlot, IPDecoderID, (void**)&ip_data)){
                printf("Failed to get IP header data\n");
                return NULL;
        }

        ip_proto=ip_data->Header->protocol;
        
        if (ip_proto!=IP_PROTO_ICMP){
#ifdef DEBUG
                printf("IP doesn't think this is an icmp packet %02x\n",ip_proto);
#endif          
                return NULL;
        }
                
        data=malloc(sizeof(ICMPData));
        data->Header=(ICMPHdr*)(p->RawPacket+p->BeginData);
        p->BeginData+=sizeof(ICMPHdr);
        
#ifdef DEBUG
        printf("ICMP Type %u Code %u\n",data->Header->type, data->Header->code); 
#endif  

        return data;
}

/*************************************
* Set up the decoder
*************************************/
int InitDecoderICMP(){
        int DecoderID;

        DEBUGPATH;
        
        if ((DecoderID=CreateDecoder("ICMP"))==DECODER_NONE){
#ifdef DEBUG
                printf("Couldn't Allocate ICMP Decoder\n");
#endif  
                return FALSE;
        }
        
        Globals.Decoders[DecoderID].DecodeFunc=DecodeICMP;
        if (!DecoderAddDecoder(GetDecoderByName("IP"), DecoderID)){
                printf("Failed to Bind ICMP Decoder to IPDefrag Decoder\n");
                return FALSE;
        }

        IPDecoderID=GetDecoderByName("IP");

        return TRUE;
}

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