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#define __USE_BSD
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#define __FAVOR_BSD /
#include <netinet/tcp.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#define P 53
struct ipheader {
unsigned char ip_hl:4, ip_v:4; /* this means that each member is 4 bits */
unsigned char ip_tos;
unsigned short int ip_len;
unsigned short int ip_id;
unsigned short int ip_off;
unsigned char ip_ttl;
unsigned char ip_p;
unsigned short int ip_sum;
unsigned int ip_src;
unsigned int ip_dst;
}; /* total ip header length: 20 bytes (=160 bits) */
struct udpheader {
unsigned short int uh_sport;
unsigned short int uh_dport;
unsigned short int uh_len;
unsigned short int uh_check;
}; /* total udp header length: 8 bytes (=64 bits) */
int
main (void)
{
int s = socket (PF_INET, SOCK_RAW, IPPROTO_UDP); /* open raw socket */
char datagram[4096]; /* this buffer will contain ip header, tcp header,
and payload. we'll point an ip header structure
at its beginning, and a tcp header structure after
that to write the header values into it */
struct ipheader *iph = (struct ipheader *) datagram;
struct udpheader *udph = (struct udpheader *) datagram + sizeof (struct ip);
struct sockaddr_in sin;
/* the sockaddr_in containing the dest. address is used
in sendto() to determine the datagrams path */
sin.sin_family = AF_INET;
sin.sin_port = htons (P);/* you byte-order >1byte header values to network
byte order (not needed on big endian machines) */
sin.sin_addr.s_addr = inet_addr ("127.0.0.1");
memset (datagram, 0, 4096); /* zero out the buffer */
/* we'll now fill in the ip header values, see above for explanations */
iph->ip_hl = 5;
iph->ip_v = 4;
iph->ip_tos = 0;
iph->ip_len = sizeof (struct ipheader) + sizeof (struct udpheader); /* no payload */
iph->ip_id = htonl (54321); /* the value doesn't matter here */
iph->ip_off = 0;
iph->ip_ttl = 255;
iph->ip_p = 6;
iph->ip_sum = 0; /* set it to 0 before computing the actual checksum later */
iph->ip_src = inet_addr ("1.2.3.4");/* SYN's can be blindly spoofed */
iph->ip_dst = sin.sin_addr.s_addr;
/* we'll now fill in the udp header values, see above for explanations */
udph->uh_sport=12345;
udph->uh_dport=htons(P);
udph->uh_len=sizeof (struct udpheader);
udph->uh_check=111;
if (sendto (s, /* our socket */
datagram, /* the buffer containing headers and data */
iph->ip_len, /* total length of our datagram */
0, /* routing flags, normally always 0 */
(struct sockaddr *) &sin, /* socket addr, just like in */
sizeof (sin)) < 0) /* a normal send() */
printf ("error\n");
return 0;
} |
