Change if

exec.sh

@@ -3,4 +3,4 @@
 
 sudo bpftool btf dump file /sys/kernel/btf/vmlinux format c > src/vmlinux.h
 make clean
-make all && sudo ./dns-trace
+make all && sudo ./dns-trace -i enx98e743c667fc

src/dns-trace.c

@@ -21,6 +21,7 @@ static struct arguments arguments;
 static int running = 1;
 
 struct arguments {
+    char *interface;
     char *filename;
     int to_output;
 };
@@ -40,6 +41,9 @@ static error_t parse_opts(int key, char *arg, struct argp_state *state){
             arguments->filename = arg;
             arguments->to_output = 0;
             break;
+        case 'i':
+            arguments->interface = arg;
+            break;
         case 'o':
             arguments->to_output = 1;
             break;
@@ -56,12 +60,14 @@ static error_t parse_opts(int key, char *arg, struct argp_state *state){
 
 struct arguments parse_args(int argc, char *argv[]){
     static const struct argp_option opts[] = {
+        {"interface", 'i', "INTERFACE", 0, "Ifname for listening"},
         {"filename", 'f', "FILENAME", 0, "Save result to logs"},
         {"to-output", 'o', NULL, 0, "Print to output"},
         {NULL, 'h', NULL, OPTION_HIDDEN, "help"},
         {},
     };
     struct arguments arguments;
+    arguments.interface = NULL;
     arguments.filename = NULL;
     arguments.to_output = 1;
     static struct argp argp = {opts, parse_opts, args_doc, doc};
@@ -76,8 +82,7 @@ static void signalHandler(int signum){
     running = 0;
 }
 
-static int open_raw_sock(const char *name)
-{
+static int open_raw_sock(const char *name) {
 	struct sockaddr_ll sll;
 	int sock;
 
@@ -92,7 +97,6 @@ static int open_raw_sock(const char *name)
 	sll.sll_ifindex = if_nametoindex(name);
 	sll.sll_protocol = htons(ETH_P_ALL);
 	if (bind(sock, (struct sockaddr *)&sll, sizeof(sll)) < 0) {
-		//printf("bind to %s: %s\n", name, strerror(errno));
         printf("Failed to bind the interface %s\n", name);
 		close(sock);
 		return -1;
@@ -340,9 +344,22 @@ int main(int argc, char *argv[]){
     struct ring_buffer *rb;
     int err;
     int fd_map_data;
+    int sock;
 
     arguments = parse_args(argc, argv); // Parsing arguments
 
+    if (arguments.interface == NULL){
+        printf("You must specified the interface name");
+        exit(-1);
+    }
+    printf("Listen to %s\n", arguments.interface);
+
+    sock = open_raw_sock(arguments.interface);
+    if (sock == -1){
+        printf("Failed to listen to the interface %s\n", arguments.interface);
+        exit(-1);
+    }
+
     signal(SIGINT, signalHandler);
 
     /* Open and load our eBPF object */
@@ -376,12 +393,8 @@ int main(int argc, char *argv[]){
     }
 
     bpf_program__attach(programSkb);
-    int sock = open_raw_sock("wlp0s20f3");
-    //int sock = open_raw_sock("enx98e743c667fc");
-    //int sock = open_raw_sock("lo");
-    printf("Socket: %d\n", sock);
     int prog_fd = bpf_program__fd(programSkb);
-    printf("Program fd: %d\n", prog_fd);
+
     setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, sizeof(int));
 
     /* Start the ringbuffer */