Packet sniffer

kodute

not sure if this is the right forum for this but here goes:

Im having some problems with this packet sniffer i wrote. It
will capture all packets fine but i also need it to send these
captured packets forwarded on to a client machine. this part of the
program is not working so well. Any help appreciated as i am at my
wits end.
Here is the code:

#include <stdio.h>
#include <sys/socket.h>
#include <resolv.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/types.h>
#include <linux/if_ether.h>
#include < string.h>

int go = -1;
int x; /*global var for passing no of bytes recieved by sniffer*/

struct ipheader { /*Ip header structure*/

unsigned char headl:4, version:4;
unsigned char tos;
unsigned short int len;
unsigned short int id_seq;
unsigned short int offset;
unsigned char ttl;
unsigned char proto;
unsigned short int chksum;
unsigned int source;
unsigned int dest;

};

struct tcpheader {

unsigned short int srcport;
unsigned short int destport;
unsigned int seqnum;
unsigned int acknum;
unsigned char x2:4, offset:4;
unsigned char flags;
unsigned short int windowsize;
unsigned short int chksum;
unsigned short int urgentptr;

};

struct udpheader {
unsigned short int srcport;
unsigned short int destport;
unsigned short int len;
unsigned short int chksum;

};

int udpForward(char *buffer)
{
    int t;

    char data2[(x+1064)];

    struct ipheader *ip=(void*)buffer;
    int store = ip->id_seq;

    printf("\n%i\n", store);

    if (store!= go){    /*this guy checks to see if this packet was
forwarded already*/
    go = store;

    strcpy(data2, buffer); /*copies whole packet into data2*/
    printf("copy successful \n");
    /*Client initiated*/

    int ipsoc = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);

    /*Now for the standard stuff*/
    struct sockaddr_in raddrin;
    raddrin.sin_family = AF_INET;
    raddrin.sin_port = htons(3333);
    raddrin.sin_addr.s_addr = inet_addr(" 192.168.1.66");/*Ip address
of data analysis client*/

/* ssize_t sendto(int socket, const void *message, size_t length,
       int flags, const struct sockaddr *dest_addr, socklen_t
dest_len);*/

    t = sendto(ipsoc, data2, sizeof(data2), 0, (struct sockaddr
*)&raddrin, x);
    printf("t= %i\n", t);
    if (t > -1)
        printf("great success\n"); /*new packet sent*/

    }

    else{
        perror( "t" );
    printf("already sent\n");
    go = -1;}

}

void sniffnetwork()
{
int n, bytes_read,i;
char data[1024];
n = socket(AF_INET, SOCK_PACKET, htons(ETH_P_IP));

if ( n < 0 )
printf("Snooper socket error");

do{
    bytes_read = recvfrom(n, data, sizeof(data), 0, 0, 0);
    if ( bytes_read > 0 ){
        x = bytes_read;
        printf("captured data:\n");
        /*for (i=0; i<=bytes_read; i++){
            printf("%X", data[i]);

            }*/
        printf("\n");
        udpForward(data);

        }
}

while ( bytes_read > 0 );

}

int main()
{
    sniffnetwork();

return 0;

}

I think UDP is appropriate for forwarding on the packets as every
single one is not essential nor is the order. The other side is a java program to pick up udp packets and have a look at their contents, ie the original captured packet.