first commit

Sniffing_Spoofing/Labsetup/volumes/sniffer.c

@@ -0,0 +1,39 @@
+#include <pcap.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet) {
+    printf("Got a packet\n");
+}
+
+int main() {
+    pcap_t *handle;
+    char errbuf[PCAP_ERRBUF_SIZE];
+    struct bpf_program fp;
+    char filter_exp[] = "icmp";
+    bpf_u_int32 net;
+
+    // Step 1: Open pcap session on the interface
+    handle = pcap_open_live("br-c031fbf1a197", BUFSIZ, 1, 1000, errbuf);
+    if (handle == NULL) {
+        fprintf(stderr, "Couldn't open device: %s\n", errbuf);
+        return 2;
+    }
+
+    // Step 2: Compile filter_exp into BPF code
+    if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
+        fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
+        return 2;
+    }
+    if (pcap_setfilter(handle, &fp) == -1) {
+        fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
+        return 2;
+    }
+
+    // Step 3: Capture packets
+    printf("Sniffing ICMP packets using C and libpcap...\n");
+    pcap_loop(handle, -1, got_packet, NULL);
+
+    pcap_close(handle);
+    return 0;
+}