Raw socket not picking up ARP requests

Question

I am attempting to write a custom packet sniffer. I am following the following tutorial...

http://www.binarytides.com/packet-sniffer-code-in-c-using-linux-sockets-bsd-part-2/

Doing so, I am unable to pick up an ARP requests packets. I do successfully pick up all other packets including ICMP, IP, etc...

Here is an overview of the code. Again, I am reading all other packets (every byte of every other packet) but I am not reading any ARP.

int main()
{
    int saddr_size , data_size;
    struct sockaddr saddr;

    unsigned char *buffer = (unsigned char *) malloc(65536); //Its Big!

    if(logfile==NULL)
    {
        printf("Unable to create log.txt file.");
    }
    printf("Starting...\n");

    int sock_raw = socket( AF_PACKET , SOCK_RAW , htons(ETH_P_ALL)) ;
    setsockopt(sock_raw , SOL_SOCKET , SO_BINDTODEVICE , "eth0" , strlen("eth0")+ 1 );

    if(sock_raw < 0)
    {
        perror("Socket Error");
        return 1;
    }
    while(1)
    {
        saddr_size = sizeof saddr;
        //Receive a packet
        data_size = recvfrom(sock_raw , buffer , 65536 , 0 , &saddr , (socklen_t*)&saddr_size);
        if(data_size <0 )
        {
            printf("Recvfrom error , failed to get packets\n");
            return 1;
        }
        //Now process the packet
        ProcessPacket(buffer , data_size);
    }
    close(sock_raw);
    printf("Finished");
    return 0;
}

Answer 1

As ARP doesn't use IP packets, you can't use recvfrom, you have to use recv.

See e.g. this example.