decoders/decode_udp.c

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#include "decode_udp.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 udp decoding
****************************************/
void* DecodeUDP(int PacketSlot){
        UDPData*                data;
        IPData*                 ip_data;
        unsigned char   ip_proto;
        PacketRec*              p;
        
        DEBUGPATH;

#ifdef DEBUG
        printf("Decoding UDP 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_UDP){
#ifdef DEBUG
                printf("IP doesn't think this is an udp packet %02x\n",ip_proto);
#endif          
                return NULL;
        }
                
        data=malloc(sizeof(UDPData));
        data->Header=(UDPHdr*)(p->RawPacket+p->BeginData);
        p->BeginData+=sizeof(UDPHdr);
        
#ifdef DEBUG
        printf("UDP %u->%u\n",ntohs(data->Header->source), ntohs(data->Header->dest)); 
#endif  

        return data;
}

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

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

        IPDecoderID=GetDecoderByName("IP");

        return TRUE;
}

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