Um...
I generated IP and UDP headers, I didn't provide a payload, and I sent using send...
I haven't found *anything* and I've been searching for two days... just a couple outdated tutorials...
My RAW sockets reader didn't accept it either... here's the code for both...
(I was just wondering cause I saw a tutorial that had bind and connect in it)
I've tried three styles, and none of them get caught... I'm not sure how to tell they are being sent either... I don't need a catcher! I need a thrower mainly...
(although I will need a catcher after a while)
Throw
#include <iostream.h>
#define P 5000
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define maxBufSize 4096
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) */
unsigned short csum (unsigned short *buf, int nwords)
{
unsigned long sum;
for (sum = 0; nwords > 0; nwords--)
sum += *buf++;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return ~sum;
}
int main(int argc, char * argv[])
{
char datagram[maxBufSize];
IPHeader *iph = (IPHeader *) datagram;
UDPHeader *udph = (UDPHeader *) datagram + sizeof(IPHeader);
memset(datagram, 0, maxBufSize);
int fd = socket (PF_INET, SOCK_RAW, IPPROTO_UDP);
sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(P);
sin.sin_addr.s_addr = inet_addr ("127.0.0.1");
iph->ip_hl = 5;
iph->ip_v = 4;
iph->ip_tos = 0;
iph->ip_len = sizeof (IPHeader) + sizeof (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;
udph->uh_sport = htons(1234);
udph->uh_dport = sin.sin_port;
udph->uh_len = sizeof(UDPHeader);
udph->uh_check = 0;
iph->ip_sum = csum ((unsigned short *) datagram, iph->ip_len >> 1);
int one = 1;
const int *val = &one;
int error = setsockopt(fd, IPPROTO_IP, IP_
if (setsockopt (fd, IPPROTO_IP, IP_HDRINCL, val, sizeof (one)) < 0)
printf ("Warning: Cannot set HDRINCL!\n");
if (write(fd, datagram, maxBufSize) > 0)
cout << "caught packet" << endl;
cout << "quiting" << endl;
return 0;
}
Catch
#include <iostream.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int argc, char * argv[])
{
int fd = socket (PF_INET, SOCK_RAW, IPPROTO_TCP);
char buffer[8192]; /* single packets are usually not bigger than 8192 bytes */
while (true)
{
if (read (fd, buffer, 8192) > 0)
cout << "caught packet" << endl;
}
cout << "quiting" << endl;
return 0;
}