#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
#include <linux/if_packet.h>
#include <net/ethernet.h>
#include <arpa/inet.h>

/* Receive raw frames using C

    Author: Tim Pierson, Dartmouth CS55, Winter 2021
        From Du: Computer and Internet Security 

    compile gcc sniff_raw.c -o sniff_raw
    run: ./sniff_raw
    
    NOTE: careful, this may get overwhelmed with network traffic!

*/

int main() {
    int PACKET_LEN = 512;
    char buffer[PACKET_LEN];
    struct sockaddr saddr;
    struct packet_mreq mr;

    // Create the raw socket
    int sock = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); 

    // Turn on the promiscuous mode.
    mr.mr_type = PACKET_MR_PROMISC;  
    setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mr, sizeof(mr));

    // Getting captured packets
    while (1) {
        int data_size=recvfrom(sock, buffer, PACKET_LEN, 0, 
                         &saddr, (socklen_t*)sizeof(saddr));
        if(data_size) printf("Got one packet\n");
    }

    close(sock);
    return 0;
}