Building and send RAW datagrams - c

Question

Hello I would like to make a programm which would work similarly to "SendIP a command-line tool to send arbitrary IP packets"
I have a programm to send "IPv4 + UDP". I try to validate my program by Wireshark but nothing is received and I don't know why.
I send it by command ./Project 192.168.1.15 21 192.168.1.15 8080 5
Here is my code: (In ipv4.h and udp.h I have ip and udp headers)
#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include "ipv4.h"
#include "udp.h"
// Source IP, source port, target IP, target port from the command line arguments
int main(int argc, char *argv[])
{
if (argc != 6)
{
printf("- Invalid parameters!!!\n");
printf(
"- Usage %s <source hostname/IP> <source port> <target hostname/IP> <target port>\n",
argv[0]);
exit(-1);
}
else {
int sd;
char buffer[PCKT_LEN];
struct ipheader *ip = (struct ipheader *) buffer;
struct udpheader *udp = (struct udpheader *) (buffer
+ sizeof(struct ipheader));
// Source and destination addresses: IP and port
struct sockaddr_in sin, din;
int one = 1;
const int *val = &one;
memset(buffer, 0, PCKT_LEN);
// Create a raw socket with UDP protocol
sd = socket(PF_INET, SOCK_RAW, IPPROTO_UDP);
if (sd < 0)
{
perror("socket() error");
// If something wrong just exit
exit(-1);
}
else
printf(
"socket() - Using SOCK_RAW socket and UDP protocol is OK.\n");
// The address family
sin.sin_family = AF_INET;
din.sin_family = AF_INET;
// Port numbers
sin.sin_port = htons(atoi(argv[2]));
din.sin_port = htons(atoi(argv[4]));
// IP addresses
sin.sin_addr.s_addr = inet_addr(argv[1]);
din.sin_addr.s_addr = inet_addr(argv[3]);
ip->iph_ihl = 5;
ip->iph_ver = 4;
ip->iph_tos = 16; // Low delay
ip->iph_len = sizeof(struct ipheader) + sizeof(struct udpheader);
ip->iph_ident = htons(54321);
ip->iph_ttl = 64; // hops
ip->iph_protocol = 17; // UDP
ip->iph_sourceip = inet_addr(argv[1]);
// The destination IP address
ip->iph_destip = inet_addr(argv[3]);
// Fabricate the UDP header. Source port number, redundant
udp->udph_srcport = htons(atoi(argv[2]));
// Destination port number
udp->udph_destport = htons(atoi(argv[4]));
udp->udph_len = htons(sizeof(struct udpheader));
// Calculate the checksum for integrity
ip->iph_chksum = csum((unsigned short *) buffer,
sizeof(struct ipheader) + sizeof(struct udpheader));
if (setsockopt(sd, IPPROTO_IP, IP_HDRINCL, val, sizeof(one)) < 0)
{
perror("setsockopt() error");
exit(-1);
}
else
printf("setsockopt() is OK.\n");
printf("Trying...\n");
printf("Using raw socket and UDP protocol\n");
printf("Using Source IP: %s port: %u, Target IP: %s port: %u.\n",
argv[1], atoi(argv[2]), argv[3], atoi(argv[4]));
//printf("Interfejs=%d\n", *val);
int count;
int number = (atoi(argv[5]));
printf("Number=%d\n", number);
for (count = 1; count <= number; count++)
{
if (sendto(sd, buffer, ip->iph_len, 0, (struct sockaddr *) &sin,
sizeof(sin)) < 0)
{
perror("sendto() error");
exit(-1);
}
else
{
printf("Count #%u - sendto() is OK.\n", count);
sleep(2);
}
}
close(sd);
return 0;
}
}

Answer 1

Ok I fix it. The problem was with int one = 1; which specife number of interface. I changed to 0 and it works. What a stupid mistake :D