+static int
+is_wifi(int sock_fd
+#ifndef IW_MODE_MONITOR
+_U_
+#endif
+, const char *device)
+{
+ char *pathstr;
+ struct stat statb;
+#ifdef IW_MODE_MONITOR
+ char errbuf[PCAP_ERRBUF_SIZE];
+#endif
+
+ /*
+ * See if there's a sysfs wireless directory for it.
+ * If so, it's a wireless interface.
+ */
+ if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
+ /*
+ * Just give up here.
+ */
+ return 0;
+ }
+ if (stat(pathstr, &statb) == 0) {
+ free(pathstr);
+ return 1;
+ }
+ free(pathstr);
+
+#ifdef IW_MODE_MONITOR
+ /*
+ * OK, maybe it's not wireless, or maybe this kernel doesn't
+ * support sysfs. Try the wireless extensions.
+ */
+ if (has_wext(sock_fd, device, errbuf) == 1) {
+ /*
+ * It supports the wireless extensions, so it's a Wi-Fi
+ * device.
+ */
+ return 1;
+ }
+#endif
+ return 0;
+}
+