Allow -1 as value to disable frag_threshold

To be consistent with the internal representation of how to disable
framentation, allow -1 as a value to disable it in configuration.

Signed-off-by: Matthias May <matthias.may@neratec.com>

hostapd/config_file.c

@@ -2700,8 +2700,10 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 		}
 	} else if (os_strcmp(buf, "fragm_threshold") == 0) {
 		conf->fragm_threshold = atoi(pos);
-		if (conf->fragm_threshold < 256 ||
-		    conf->fragm_threshold > 2346) {
+		if (conf->fragm_threshold == -1) {
+			/* allow a value of -1 */
+		} else if (conf->fragm_threshold < 256 ||
+			   conf->fragm_threshold > 2346) {
 			wpa_printf(MSG_ERROR,
 				   "Line %d: invalid fragm_threshold %d",
 				   line, conf->fragm_threshold);

hostapd/hostapd.conf

@@ -197,11 +197,11 @@ max_num_sta=255
 # RTS threshold and 'iwconfig wlan# rts <val>' can be used to set it.
 rts_threshold=-1
 
-# Fragmentation threshold; 2346 = disabled (default); range 256..2346
+# Fragmentation threshold; -1 = disabled (default); range -1, 256..2346
 # If this field is not included in hostapd.conf, hostapd will not control
 # fragmentation threshold and 'iwconfig wlan# frag <val>' can be used to set
 # it.
-fragm_threshold=2346
+fragm_threshold=-1
 
 # Rate configuration
 # Default is to enable all rates supported by the hardware. This configuration