#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <sys/ioctl.h>
unsigned long int get_host_ip ()
{
int tempSock = socket(PF_INET, SOCK_DGRAM, 0);
struct ifreq ifr;
strcpy(ifr.ifr_name, "eth0");
if (ioctl(tempSock, SIOCGIFADDR, &ifr) < 0) { printf("error: ioctl\n"); exit (0); }
close (tempSock);
unsigned long int host_ip = (((struct sockaddr_in *)&(ifr.ifr_addr))->sin_addr).s_addr;
return host_ip;
}
long int get_random (void)
{
int fd = 0;
if ((fd = open ("/dev/urandom", O_RDONLY | O_NONBLOCK)) == -1) { printf ("error: open /dev/urandom. exit\n"); exit (0); }
long int buf;
if (read (fd, (char *)&buf, 4) != 4) { printf ("error: read /dev/urandom. exit\n"); exit (0); }
if (close (fd) != 0) { printf ("error: close() fd. exit\n"); exit (0); }
return buf;
}
unsigned short csum (unsigned short *buf, int nwords) /* generates header checksums */
{
unsigned long sum;
for (sum = 0; nwords > 0; nwords--)
sum += *buf++;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return ~sum;
}
struct pseudohdr {
u_int32_t saddr; /* source IP address */
u_int32_t daddr; /* destination IP address */
u_int8_t res; /* contains binary zeroes.(0) */
u_int8_t ptcl; /* protocol. can be tcp (6), udp(17), icmp(1) */
u_int16_t len; /* TCP/UDP packet length. (unit:byte) */
};
int main (int argc, char *argv[])
{
if (argc != 5) { printf ("usage: %s fromip toip fromport toport\n", argv[0]); exit (0); }
unsigned long fromip, toip;
fromip = ntohl(inet_addr(argv[1])); toip = ntohl(inet_addr(argv[2])); /* inet_aton() returns non-zero if the address is valid, zero if not. */
if ((fromip == 0) || (toip == 0) || ((toip-fromip) < 0)) { printf ("error: fromip or toip\n"); exit (0); }
unsigned short fromport, toport;
fromport = atoi (argv[3]); toport = atoi (argv[4]);
if ((fromport == 0) || (toport == 0) || ((toport-fromport) < 0)) { printf ("error: fromport or toport\n"); exit (0); }
int raw_sock_tcp;
if ((raw_sock_tcp = socket(PF_INET, SOCK_RAW, IPPROTO_TCP)) == -1) { printf("socket() failed!\nMust be root to make raw socket.\n"); exit(0); }
unsigned char packet[80]; bzero (packet, 80);
struct tcphdr *tcph = (struct tcphdr *)packet;
/* fill in the tcp header values */
// tcph->source = htons (1234);
tcph->source = htons (get_random());
tcph->dest = htons (1);
tcph->seq = get_random (); /* in a SYN packet, the sequence is a random */
tcph->ack_seq = 0; /* number, and the ack sequence is 0 in the 1st packet */
tcph->doff = 5;
tcph->syn = 1; /* initial connection request */
tcph->window = htonl (65535); /* maximum allowed window size */
tcph->check = 0;
tcph->urg_ptr = 0;
struct sockaddr_in dest; bzero (&dest, sizeof (dest));
dest.sin_family = PF_INET; dest.sin_addr.s_addr = inet_addr ("1.2.3.4"); dest.sin_port = htons (1);
unsigned long int host_ip = get_host_ip ();
int ip_i,port_i;
for(ip_i = 0; ip_i <= (toip-fromip); ip_i++) {
for(port_i = 0; port_i <= (toport-fromport); port_i++) {
dest.sin_addr.s_addr = htonl (fromip + ip_i); dest.sin_port = htons (fromport + port_i);
tcph->dest = htons (fromport + port_i);
tcph->source = htons (get_random());
tcph->seq = get_random (); /* in a SYN packet, the sequence is a random */
unsigned char buf[512]; bzero (buf, 512);
struct pseudohdr *pseudohdr;
pseudohdr = (struct pseudohdr *)buf;
/* full pseudohdr */
pseudohdr->daddr = dest.sin_addr.s_addr;
pseudohdr->saddr = host_ip;
pseudohdr->res = 0; pseudohdr->ptcl = 0x06;
pseudohdr->len = htons((tcph->doff)<<2);
tcph->check = 0;
memcpy((unsigned char *)pseudohdr+sizeof(struct pseudohdr), (unsigned char *)tcph, (tcph->doff)<<2);
tcph->check = csum((unsigned short *)pseudohdr, (((tcph->doff)<<2) + sizeof(struct pseudohdr))>>1);
if (sendto (raw_sock_tcp, packet, /* the buffer containing headers and data */
((tcph->doff)<<2), /* total length of our packet */
0, (struct sockaddr *) &dest, sizeof (struct sockaddr)) < 0)
printf ("error: sendto()\n");
fd_set readfs; /* file descriptor set */
FD_ZERO (&readfs); FD_SET (raw_sock_tcp, &readfs);
struct timeval timeout = {0, 0}; /* 0s */
while (select (raw_sock_tcp+1, &readfs, NULL, NULL, &timeout)) {
bzero (buf, 512);
int n_recv;
n_recv = recvfrom(raw_sock_tcp, buf, 512, 0, NULL, NULL);
if(n_recv < 40) { continue; } /* 20byte ip header + 20byte tcp header */
if(buf [33] == 0x12) {
printf ("%d.%d.%d.%d %d\n", buf[12], buf[13], buf[14], buf[15],
((buf[20]<<8)&0XFF00 | buf[21]&0XFF));
}
}
}
}
return 0;
}