From: Felix Fietkau <nbd@nbd.name>
Date: Tue, 27 Jul 2021 20:28:58 +0200
Subject: [PATCH] hostapd: make the snooping interface (for proxyarp)
 configurable

Use the VLAN interface instead of the bridge, to ensure that hostapd receives
untagged DHCP packets

--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2451,6 +2451,8 @@ static int hostapd_config_fill(struct ho
 			os_strlcpy(bss->wds_bridge, pos, sizeof(bss->wds_bridge));
 	} else if (os_strcmp(buf, "bridge_hairpin") == 0) {
 		bss->bridge_hairpin = atoi(pos);
+	} else if (os_strcmp(buf, "snoop_iface") == 0) {
+		os_strlcpy(bss->snoop_iface, pos, sizeof(bss->snoop_iface));
 	} else if (os_strcmp(buf, "vlan_bridge") == 0) {
 		os_strlcpy(bss->vlan_bridge, pos, sizeof(bss->vlan_bridge));
 	} else if (os_strcmp(buf, "wds_bridge") == 0) {
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -284,6 +284,7 @@ struct hostapd_bss_config {
 	char iface[IFNAMSIZ + 1];
 	char bridge[IFNAMSIZ + 1];
 	char ft_iface[IFNAMSIZ + 1];
+	char snoop_iface[IFNAMSIZ + 1];
 	char vlan_bridge[IFNAMSIZ + 1];
 	char wds_bridge[IFNAMSIZ + 1];
 	int bridge_hairpin; /* hairpin_mode on bridge members */
--- a/src/ap/ap_drv_ops.h
+++ b/src/ap/ap_drv_ops.h
@@ -366,12 +366,12 @@ static inline int hostapd_drv_br_port_se
 
 static inline int hostapd_drv_br_set_net_param(struct hostapd_data *hapd,
 					       enum drv_br_net_param param,
-					       unsigned int val)
+					       const char *ifname, unsigned int val)
 {
 	if (hapd->driver == NULL || hapd->drv_priv == NULL ||
 	    hapd->driver->br_set_net_param == NULL)
 		return -1;
-	return hapd->driver->br_set_net_param(hapd->drv_priv, param, val);
+	return hapd->driver->br_set_net_param(hapd->drv_priv, param, ifname, val);
 }
 
 static inline int hostapd_drv_vendor_cmd(struct hostapd_data *hapd,
--- a/src/ap/x_snoop.c
+++ b/src/ap/x_snoop.c
@@ -33,28 +33,31 @@ int x_snoop_init(struct hostapd_data *ha
 
 	hapd->x_snoop_initialized = true;
 
-	if (hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_HAIRPIN_MODE,
+	if (!conf->snoop_iface[0] &&
+	    hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_HAIRPIN_MODE,
 					 1)) {
 		wpa_printf(MSG_DEBUG,
 			   "x_snoop: Failed to enable hairpin_mode on the bridge port");
 		return -1;
 	}
 
-	if (hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_PROXYARP, 1)) {
+	if (!conf->snoop_iface[0] &&
+	    hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_PROXYARP, 1)) {
 		wpa_printf(MSG_DEBUG,
 			   "x_snoop: Failed to enable proxyarp on the bridge port");
 		return -1;
 	}
 
 	if (hostapd_drv_br_set_net_param(hapd, DRV_BR_NET_PARAM_GARP_ACCEPT,
-					 1)) {
+					 conf->snoop_iface[0] ? conf->snoop_iface : NULL, 1)) {
 		wpa_printf(MSG_DEBUG,
 			   "x_snoop: Failed to enable accepting gratuitous ARP on the bridge");
 		return -1;
 	}
 
 #ifdef CONFIG_IPV6
-	if (hostapd_drv_br_set_net_param(hapd, DRV_BR_MULTICAST_SNOOPING, 1)) {
+	if (!conf->snoop_iface[0] &&
+	    hostapd_drv_br_set_net_param(hapd, DRV_BR_MULTICAST_SNOOPING, NULL, 1)) {
 		wpa_printf(MSG_DEBUG,
 			   "x_snoop: Failed to enable multicast snooping on the bridge");
 		return -1;
@@ -73,8 +76,12 @@ x_snoop_get_l2_packet(struct hostapd_dat
 {
 	struct hostapd_bss_config *conf = hapd->conf;
 	struct l2_packet_data *l2;
+	const char *ifname = conf->bridge;
+
+	if (conf->snoop_iface[0])
+		ifname = conf->snoop_iface;
 
-	l2 = l2_packet_init(conf->bridge, NULL, ETH_P_ALL, handler, hapd, 1);
+	l2 = l2_packet_init(ifname, NULL, ETH_P_ALL, handler, hapd, 1);
 	if (l2 == NULL) {
 		wpa_printf(MSG_DEBUG,
 			   "x_snoop: Failed to initialize L2 packet processing %s",
@@ -127,9 +134,12 @@ void x_snoop_mcast_to_ucast_convert_send
 
 void x_snoop_deinit(struct hostapd_data *hapd)
 {
+	struct hostapd_bss_config *conf = hapd->conf;
+
 	if (!hapd->x_snoop_initialized)
 		return;
-	hostapd_drv_br_set_net_param(hapd, DRV_BR_NET_PARAM_GARP_ACCEPT, 0);
+	hostapd_drv_br_set_net_param(hapd, DRV_BR_NET_PARAM_GARP_ACCEPT,
+				     conf->snoop_iface[0] ? conf->snoop_iface : NULL, 0);
 	hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_PROXYARP, 0);
 	hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_HAIRPIN_MODE, 0);
 	hapd->x_snoop_initialized = false;
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -4278,7 +4278,7 @@ struct wpa_driver_ops {
 	 * Returns: 0 on success, negative (<0) on failure
 	 */
 	int (*br_set_net_param)(void *priv, enum drv_br_net_param param,
-				unsigned int val);
+				const char *ifname, unsigned int val);
 
 	/**
 	 * get_wowlan - Get wake-on-wireless status
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -12376,7 +12376,7 @@ static const char * drv_br_net_param_str
 
 
 static int wpa_driver_br_set_net_param(void *priv, enum drv_br_net_param param,
-				       unsigned int val)
+				       const char *ifname, unsigned int val)
 {
 	struct i802_bss *bss = priv;
 	char path[128];
@@ -12402,8 +12402,11 @@ static int wpa_driver_br_set_net_param(v
 			return -EINVAL;
 	}
 
+	if (!ifname)
+		ifname = bss->brname;
+
 	os_snprintf(path, sizeof(path), "/proc/sys/net/ipv%d/conf/%s/%s",
-		    ip_version, bss->brname, param_txt);
+		    ip_version, ifname, param_txt);
 
 set_val:
 	if (linux_write_system_file(path, val))