wlantest: Add -F option for assuming FCS is included

When using DLT_IEEE802_11 datalink type in a pcap file, wlantest can now
be instructed to assume there is an FCS included in the frame by adding
the new -F command line argument. This will make wlantest validate the
FCS and strip it from the frame before processing.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

wlantest/process.c

@@ -380,5 +380,19 @@ void wlantest_process_prism(struct wlantest *wt, const u8 *data, size_t len)
 void wlantest_process_80211(struct wlantest *wt, const u8 *data, size_t len)
 {
 	wpa_hexdump(MSG_EXCESSIVE, "Process data", data, len);
+
+	if (wt->assume_fcs && len >= 4) {
+		const u8 *fcspos;
+
+		len -= 4;
+		fcspos = data + len;
+		if (check_fcs(data, len, fcspos) < 0) {
+			wpa_printf(MSG_EXCESSIVE, "Drop RX frame with invalid "
+				   "FCS");
+			wt->fcs_error++;
+			return;
+		}
+	}
+
 	rx_frame(wt, data, len);
 }

wlantest/wlantest.c

@@ -25,7 +25,7 @@ static void wlantest_terminate(int sig, void *signal_ctx)
 
 static void usage(void)
 {
-	printf("wlantest [-cddhqq] [-i<ifname>] [-r<pcap file>] "
+	printf("wlantest [-cddhqqF] [-i<ifname>] [-r<pcap file>] "
 	       "[-p<passphrase>]\n"
 		"         [-I<wired ifname>] [-R<wired pcap file>] "
 	       "[-P<RADIUS shared secret>]\n"
@@ -208,7 +208,7 @@ int main(int argc, char *argv[])
 	wlantest_init(&wt);
 
 	for (;;) {
-		c = getopt(argc, argv, "cdf:hi:I:p:P:qr:R:w:W:");
+		c = getopt(argc, argv, "cdf:Fhi:I:p:P:qr:R:w:W:");
 		if (c < 0)
 			break;
 		switch (c) {
@@ -223,6 +223,9 @@ int main(int argc, char *argv[])
 			if (add_pmk_file(&wt, optarg) < 0)
 				return -1;
 			break;
+		case 'F':
+			wt.assume_fcs = 1;
+			break;
 		case 'h':
 			usage();
 			return 0;

wlantest/wlantest.h

@@ -175,6 +175,8 @@ struct wlantest {
 	u8 last_hdr[30];
 	size_t last_len;
 	int last_mgmt_valid;
+
+	unsigned int assume_fcs:1;
 };
 
 int add_wep(struct wlantest *wt, const char *key);