Make IPv6 NA multicast-to-unicast conversion configurable

This can be used with Proxy ARP to allow multicast NAs to be forwarded
to associated STAs using link layer unicast delivery. This used to be
hardcoded to be enabled, but it is now disabled by default and can be
enabled with na_mcast_to_ucast=1. This functionality may not be desired
in all networks and most cases work without it, so the new
default-to-disabled is more appropriate.

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

hostapd/config_file.c

@@ -3138,6 +3138,8 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 		bss->disable_dgaf = atoi(pos);
 	} else if (os_strcmp(buf, "proxy_arp") == 0) {
 		bss->proxy_arp = atoi(pos);
+	} else if (os_strcmp(buf, "na_mcast_to_ucast") == 0) {
+		bss->na_mcast_to_ucast = atoi(pos);
 	} else if (os_strcmp(buf, "osen") == 0) {
 		bss->osen = atoi(pos);
 	} else if (os_strcmp(buf, "anqp_domain_id") == 0) {

hostapd/hostapd.conf

@@ -1493,6 +1493,13 @@ own_ip_addr=127.0.0.1
 # 1 = enabled
 #proxy_arp=1
 
+# IPv6 Neighbor Advertisement multicast-to-unicast conversion
+# This can be used with Proxy ARP to allow multicast NAs to be forwarded to
+# associated STAs using link layer unicast delivery.
+# 0 = disabled (default)
+# 1 = enabled
+#na_mcast_to_ucast=0
+
 ##### IEEE 802.11u-2011 #######################################################
 
 # Enable Interworking service

src/ap/ap_config.h

@@ -490,6 +490,7 @@ struct hostapd_bss_config {
 
 	int osen;
 	int proxy_arp;
+	int na_mcast_to_ucast;
 #ifdef CONFIG_HS20
 	int hs20;
 	int disable_dgaf;

src/ap/ndisc_snoop.c

@@ -81,6 +81,18 @@ static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)
 }
 
 
+static void ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)
+{
+	struct sta_info *sta;
+
+	for (sta = hapd->sta_list; sta; sta = sta->next) {
+		if (!(sta->flags & WLAN_STA_AUTHORIZED))
+			continue;
+		x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);
+	}
+}
+
+
 static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
 			 size_t len)
 {
@@ -133,16 +145,12 @@ static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,
 		}
 		break;
 	case ROUTER_ADVERTISEMENT:
-		if (!hapd->conf->disable_dgaf)
-			return;
-		/* fall through */
+		if (hapd->conf->disable_dgaf)
+			ucast_to_stas(hapd, buf, len);
+		break;
 	case NEIGHBOR_ADVERTISEMENT:
-		for (sta = hapd->sta_list; sta; sta = sta->next) {
-			if (!(sta->flags & WLAN_STA_AUTHORIZED))
-				continue;
-			x_snoop_mcast_to_ucast_convert_send(hapd, sta,
-							    (u8 *) buf, len);
-		}
+		if (hapd->conf->na_mcast_to_ucast)
+			ucast_to_stas(hapd, buf, len);
 		break;
 	default:
 		break;