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#include <unistd.h>
#include <arpa/inet.h>
#include <pcap.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <time.h>
u_char *packet;
struct pcap_pkthdr *header;
pcap_t *handle;
char *fichier = NULL;
/* Taille max de paquet */
#define SNAP_LEN 1518
/* taille en-tete ethernet */
#define SIZE_ETHERNET 14
/* adresse ethernet */
#define ETHER_ADDR_LEN 6
/* en-tete ethernet */
struct sniff_ethernet {
u_char ether_dhost[ETHER_ADDR_LEN]; /* adresse destination */
u_char ether_shost[ETHER_ADDR_LEN]; /* adresse source */
u_short ether_type; /* type de protocole */
};
/* en-tete IP */
struct sniff_ip {
u_char ip_vhl; /* version << 4 | header length >> 2 */
u_char ip_tos; /* type of service */
u_short ip_len; /* total length */
u_short ip_id; /* identification */
u_short ip_off; /* fragment offset field */
#define IP_RF 0x8000 /* reserved fragment flag */
#define IP_DF 0x4000 /* dont fragment flag */
#define IP_MF 0x2000 /* more fragments flag */
#define IP_OFFMASK 0x1fff /* mask for fragmenting bits */
u_char ip_ttl; /* time to live */
u_char ip_p; /* protocol */
u_short ip_sum; /* checksum */
struct in_addr ip_src,ip_dst; /* source and dest address */
};
#define IP_HL(ip) (((ip)->ip_vhl) & 0x0f)
#define IP_V(ip) (((ip)->ip_vhl) >> 4)
/* en-tete TCP */
typedef u_int tcp_seq;
struct sniff_tcp {
u_short th_sport; /* port source */
u_short th_dport; /* port destination */
tcp_seq th_seq; /* sequence number */
tcp_seq th_ack; /* acknowledgement number */
u_char th_offx2; /* data offset, rsvd */
#define TH_OFF(th) (((th)->th_offx2 & 0xf0) >> 4)
u_char th_flags;
#define TH_FIN 0x01
#define TH_SYN 0x02
#define TH_RST 0x04
#define TH_PUSH 0x08
#define TH_ACK 0x10
#define TH_URG 0x20
#define TH_ECE 0x40
#define TH_CWR 0x80
#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
u_short th_win; /* window */
u_short th_sum; /* checksum */
u_short th_urp; /* urgent pointer */
};
void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet);
void print_payload(const u_char *payload, int len);
void print_hex_ascii_line(const u_char *payload, int len, int offset);
void dump_packet(u_char * args, const struct pcap_pkthdr *header, const u_char *packet)
{
pcap_dump_open(handle, fichier);
pcap_dump((u_char *) args,header,packet);
}
void print_hex_ascii_line(const u_char *payload, int len, int offset)
{
int i;
int gap;
const u_char *ch;
/* offset */
printf("%05d ", offset);
/* hex */
ch = payload;
for(i = 0; i < len; i++) {
printf("%02x ", *ch);
ch++;
/* print extra space after 8th byte for visual aid */
if (i == 7)
printf(" ");
}
/* print space to handle line less than 8 bytes */
if (len < 8)
printf(" ");
/* fill hex gap with spaces if not full line */
if (len < 16) {
gap = 16 - len;
for (i = 0; i < gap; i++) {
printf(" ");
}
}
printf(" ");
/* ascii (if printable) */
ch = payload;
for(i = 0; i < len; i++) {
if (isprint(*ch))
printf("%c", *ch);
else
printf(".");
ch++;
}
printf("\n");
return;
}
void print_payload(const u_char *payload, int len)
{
int len_rem = len;
int line_width = 16; /* number of bytes per line */
int line_len;
int offset = 0; /* zero-based offset counter */
const u_char *ch = payload;
if (len <= 0)
return;
/* data fits on one line */
if (len <= line_width) {
print_hex_ascii_line(ch, len, offset);
return;
}
/* data spans multiple lines */
for ( ;; ) {
/* compute current line length */
line_len = line_width % len_rem;
/* print line */
print_hex_ascii_line(ch, line_len, offset);
/* compute total remaining */
len_rem = len_rem - line_len;
/* shift pointer to remaining bytes to print */
ch = ch + line_len;
/* add offset */
offset = offset + line_width;
/* check if we have line width chars or less */
if (len_rem <= line_width) {
/* print last line and get out */
print_hex_ascii_line(ch, len_rem, offset);
break;
}
}
return;
}
void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet)
{
dump_packet(args,header,packet);
static int count = 1; /* packet counter */
/* declare pointers to packet headers */
const struct sniff_ethernet *ethernet; /* The ethernet header [1] */
const struct sniff_ip *ip; /* The IP header */
const struct sniff_tcp *tcp; /* The TCP header */
const char *payload; /* Packet payload */
int size_ip;
int size_tcp;
int size_payload;
printf("\nPaquet Numero %d:\n", count);
count++;
/* define ethernet header */
ethernet = (struct sniff_ethernet*)(packet);
/* define/compute ip header offset */
ip = (struct sniff_ip*)(packet + SIZE_ETHERNET);
size_ip = IP_HL(ip)*4;
if (size_ip < 20) {
printf(" * Longueur en-tete IP invalide: %u octets\n", size_ip);
return;
}
/* print source and destination IP addresses */
printf(" Source: %s\n", inet_ntoa(ip->ip_src));
printf("Destination: %s\n", inet_ntoa(ip->ip_dst));
/* determine protocol */
switch(ip->ip_p) {
case IPPROTO_TCP:
printf(" Protocole: TCP\n");
break;
case IPPROTO_UDP:
printf(" Protocole: UDP\n");
return;
case IPPROTO_ICMP:
printf(" Protocole: ICMP\n");
return;
case IPPROTO_IP:
printf(" Protocole: IP\n");
return;
default:
printf(" Protocole: inconnu\n");
return;
}
/*
* OK, this packet is TCP.
*/
/* define/compute tcp header offset */
tcp = (struct sniff_tcp*)(packet + SIZE_ETHERNET + size_ip);
size_tcp = TH_OFF(tcp)*4;
if (size_tcp < 20) {
printf(" * Longueur en-tete TCP invalide: %u octets\n", size_tcp);
return;
}
printf(" Port source: %d\n", ntohs(tcp->th_sport));
printf("Port destination: %d\n", ntohs(tcp->th_dport));
/* define/compute tcp payload (segment) offset */
payload = (u_char *)(packet + SIZE_ETHERNET + size_ip + size_tcp);
/* compute tcp payload (segment) size */
size_payload = ntohs(ip->ip_len) - (size_ip + size_tcp);
/*
* Print payload data; it might be binary, so don't just
* treat it as a string.
*/
if (size_payload > 0) {
printf(" Payload (%d bytes):\n", size_payload);
print_payload(payload, size_payload);
}
return;
}
int main (int argc, char **argv)
{
char *interface = NULL;
char *filtre = NULL;
int index;
int options;
opterr = 0;
char *device = NULL;
char errbuf[PCAP_ERRBUF_SIZE];
bpf_u_int32 net,mask;
struct in_addr in;
pcap_dumper_t *dumpdesc;
struct bpf_program fp; /* filtre */
/* Récupération des options */
while ((options = getopt (argc, argv, "i:d:f:")) != -1)
switch (options)
{
case 'i':
interface = optarg;
break;
case 'd':
fichier = optarg;
break;
case 'f':
filtre = optarg;
break;
case '?':
if (optopt == 'i')
fprintf (stderr, "Option -%c necessite un argument.\n", optopt);
else if (isprint (optopt))
fprintf (stderr, "Option inconnu `-%c'.\n", optopt);
else
fprintf (stderr, "Option inconnu `\\x%x'.\n", optopt);
if (optopt == 'd')
fprintf (stderr, "Option -%c necessite un argument.\n", optopt);
else if (isprint (optopt))
fprintf (stderr, "Option inconnu `-%c'.\n", optopt);
else
fprintf (stderr,"Option inconnu `\\x%x'.\n", optopt);
if (optopt == 'f')
fprintf (stderr, "Option -%c necessite un argument.\n", optopt);
else if (isprint (optopt))
fprintf (stderr, "Option inconnu `-%c'.\n", optopt);
else
fprintf (stderr,"Option inconnu `\\x%x'.\n", optopt);
return 1;
default:
abort ();
}
//printf ("interface = %s, fichier = %s, filtre = %s\n", interface, fichier, filtre);
for (index = optind; index < argc; index++)
printf ("Argument manquant %s\n", argv[index]);
/* Detection de l'interface de capture */
if (interface == NULL)
{
device = pcap_lookupdev(errbuf);
if (device == NULL) {
printf("Une erreur a été détectée: %s\n", errbuf);
}
} else {
device = interface;
if (device == NULL) {
printf("Une erreur a été détectée: %s\n", errbuf);
} else {
printf("Périphérique de capture: %s\n",device);
}
}
if (pcap_lookupnet(device, &net, &mask, errbuf) == -1) {
printf("Une erreur a été détectée: %s\n", errbuf);
} else {
printf("Périphérique: %s\n", device);
in.s_addr = net;
printf("Réseau: %s\n", inet_ntoa(in));
in.s_addr = mask;
printf("Masque: %s\n", inet_ntoa(in));
}
/* Obtenir un descripteur de capture de paquet */
handle = pcap_open_live(device, SNAP_LEN, 1, 1000, errbuf);
if (handle == NULL) {
fprintf(stderr, "Couldn't open device %s: %s\n", device, errbuf);
exit(EXIT_FAILURE);
}
/* Compiler l'expression filtre */
if (pcap_compile(handle, &fp, filtre, 0, net) == -1) {
fprintf(stderr, "Verifier l'expresion filtre %s: %s\n", &filtre, pcap_geterr(handle));
exit(EXIT_FAILURE);
}
/* Appliquer le filtre */
if (pcap_setfilter(handle, &fp) == -1) {
fprintf(stderr, "erreur lors de l'application du filtre %s: %s\n", &filtre, pcap_geterr(handle));
exit(EXIT_FAILURE);
}
/* fonction callback */
//dumpdesc = pcap_dump_open(handle, fichier);
pcap_loop(handle,-1, got_packet, NULL);
/* cleanup */
pcap_freecode(&fp);
pcap_close(handle);
printf("\nCapture terminé.\n");
return 0;
} |
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