132 lines
3.6 KiB
C
132 lines
3.6 KiB
C
//
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// Created by ako on 8/22/25.
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//
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netinet/ip.h>
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#include <netinet/if_ether.h>
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#include <netpacket/packet.h>
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#include <net/ethernet.h>
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#include <errno.h>
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#include "nethdr.h"
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#include "npcap_handle.h"
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#include <netpacket/packet.h>
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#include <net/if.h>
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#include <netinet/ip_icmp.h>
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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void cleanup(int socket, unsigned char* buffer) {
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close(socket);
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free(buffer);
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}
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int main()
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{
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if (geteuid() != 0)
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{
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printf("Please run me as root.\n");
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return 1;
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}
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int sock_raw = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
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if (sock_raw < 0)
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{
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fprintf(stderr, "Unable to connect to network socket.\n");
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return -1;
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}
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unsigned char *buffer = (unsigned char *) calloc(65536, sizeof(unsigned char));
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if (buffer == NULL) {
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fprintf(stderr, "Unable to connect to allocate memory.\n");
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cleanup(sock_raw, buffer);
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return 1;
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}
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struct sockaddr_ll sourceaddr;
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socklen_t sourceaddr_len = sizeof(sourceaddr);
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int loopback_ifindex = if_nametoindex("lo");
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if (loopback_ifindex == 0) {
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perror("if_nametoindex for lo");
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cleanup(sock_raw, buffer);
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return 1;
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}
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while (1) {
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ssize_t buflen = recvfrom(sock_raw, buffer, 65536, 0, (struct sockaddr *)&sourceaddr, &sourceaddr_len);
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if (buflen == -1) {
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perror("Couldn't read from socket");
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cleanup(sock_raw, buffer);
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return 1;
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}
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if (sourceaddr.sll_ifindex == loopback_ifindex) {
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continue;
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}
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printf("\n===== Paquet reçu =====\n");
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printf("Paquet de %ld octets\n", buflen);
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// Debug
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printf("Hexdump des 32 premiers octets:\n");
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for (int i = 0; i < 32 && i < buflen; i++) {
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printf("%02x ", buffer[i]);
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if ((i + 1) % 8 == 0) printf(" ");
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}
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printf("\n");
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//
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// COUCHE 2
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//
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// Décodage entête Ethernet
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struct ethhdr *eth = (struct ethhdr *)buffer;
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handle_eth(eth);
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//
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// COUCHE 3
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//
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switch (ntohs(eth->h_proto))
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{
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// Décodage entête ARP
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case ETH_P_ARP:
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struct arphdr_c *arp = (struct arphdr_c *) (buffer + sizeof(struct ethhdr));
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handle_arp(arp);
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break;
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case ETH_P_IP:
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struct iphdr *ip = (struct iphdr *) (buffer + sizeof(struct ethhdr));
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handle_ip(ip);
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switch (ip->protocol) {
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case 0x01:
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struct icmphdr *icmp = (struct icmphdr *) (buffer + sizeof(struct ethhdr) + ip->ihl * 4);
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handle_icmp(icmp);
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break;
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case 0x06:
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struct tcphdr *tcp = (struct tcphdr *) (buffer + sizeof(struct ethhdr) + ip->ihl * 4);
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handle_tcp(tcp);
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break;
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case 0x11:
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struct udphdr *udp = (struct udphdr *) (buffer + sizeof(struct ethhdr) + ip->ihl * 4);
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handle_udp(udp);
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break;
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default:
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break;
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}
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break;
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}
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// printf("\n=======================\n");
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}
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cleanup(sock_raw, buffer);
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}
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