decoders/decode_ip.c

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#include "decode_ip.h"
#include "decode_ethernet.h"
#include "../packets/packet.h"
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>

//#define DEBUG

extern GlobalVars       Globals;

int     EthernetDecoderID;

/***************************************
* Apply the ip decoding
****************************************/
void* DecodeIP(int PacketSlot){
        IPData*                 data;
        EthernetData*   edata;
        unsigned short  etype;
        PacketRec*              p;
        
        DEBUGPATH;

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

        p=&Globals.Packets[PacketSlot];

        if (!GetDataByID(PacketSlot, EthernetDecoderID, (void**)&edata)){
                printf("2Failed to get Ethernet header data\n");
                return NULL;
        }

        etype=ntohs(edata->Header->Type);
        
        if (etype!=ETHERNET_TYPE_IP){
#ifdef DEBUG
                printf("Ethernet doesn't think this is an IP packet %04x\n",etype);
#endif          
                return NULL;
        }
                
        data=malloc(sizeof(IPData));
        data->Header=(IPHdr*)(p->RawPacket+p->BeginData);
        p->BeginData+=(data->Header->ihl*4);
        
#ifdef DEBUG
        printf("IP %s->",inet_ntoa(*(struct in_addr*)&data->Header->saddr));
        printf("%s\n",inet_ntoa(*(struct in_addr*)&data->Header->daddr));
#endif  

        return data;
}

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

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

        EthernetDecoderID=GetDecoderByName("Ethernet");

        return TRUE;
}

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