53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
#include <pcap.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <arpa/inet.h>
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struct ipheader {
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unsigned char iph_ihl:4, iph_ver:4;
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unsigned char iph_tos;
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unsigned short int iph_len;
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unsigned short int iph_ident;
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unsigned short int iph_flag:3, iph_offset:13;
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unsigned char iph_ttl;
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unsigned char iph_protocol;
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unsigned short int iph_chksum;
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struct in_addr iph_sourceip;
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struct in_addr iph_destip;
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};
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void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet)
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{
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struct ipheader *ip = (struct ipheader *)(packet + 14); // Skip ethernet header
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printf("Got a packet\n");
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printf(" From: %s\n", inet_ntoa(ip->iph_sourceip));
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printf(" To: %s\n", inet_ntoa(ip->iph_destip));
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fflush(stdout);
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}
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int main()
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{
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pcap_t *handle;
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char errbuf[PCAP_ERRBUF_SIZE];
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struct bpf_program fp;
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char filter_exp[] = "icmp";
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bpf_u_int32 net;
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// Change interface name to the correct one
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handle = pcap_open_live("br-603d3788c443", BUFSIZ, 1, 1000, errbuf);
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if (handle == NULL) {
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fprintf(stderr, "Couldn't open device: %s\n", errbuf);
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return 2;
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}
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pcap_compile(handle, &fp, filter_exp, 0, net);
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if (pcap_setfilter(handle, &fp) != 0) {
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pcap_perror(handle, "Error:");
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exit(EXIT_FAILURE);
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}
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pcap_loop(handle, -1, got_packet, NULL);
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pcap_close(handle);
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return 0;
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}
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