Lectures notes for 2010 - KTH

Building a UDP packet from scratch
/* simple example of building a UDP packet from scratch, based on the program:
PingPong - 970621 by Willy TARREAU
http://www.insecure.org/sploits/inetd.internal_udp_ports.DOS.attack.html
As this program uses RAW sockets, you must be root to run it
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
struct sockaddr addrfrom;
struct sockaddr addrto;
int s;
u_char outpack[65536];
struct iphdr *ip;
struct udphdr *udp;
main(int argc, char **argv) {
struct sockaddr_in *from;
struct sockaddr_in *to;
struct protoent *proto;
int i;
char *src,*dest;
int srcp, destp;
int packetsize,datasize;
if (argc!=5) {fprintf(stderr,"Usage: %s src_addr src_port dst_addr dst_port\n", argv[0]);
fprintf(stderr,"src_addr and dst_addr must be given as IP addresses (xxx.xxx.xxx.xxx)\n");
exit(2);}
src=argv[1]; srcp=atoi(argv[2]); dest=argv[3]; destp=atoi(argv[4]);
Maguire Building a UDP packet from scratch 4: 24 of 74
maguire@kth.se 2010.03.21 Internetworking/Internetteknik