AP: Add support for setting bridge port attributes

This allows setting a bridge port attribute. Specifically, the bridge
port in this context is the port to which the BSS belongs.

This commit adds the needed functionality in driver_nl80211.c for the
Linux bridge implementation. In theory, this could be shared with
multiple Linux driver interfaces, but for now, only the main nl80211
interface is supported.

Signed-off-by: Kyeyoon Park <kyeyoonp@qca.qualcomm.com>

src/ap/ap_drv_ops.h

@@ -300,6 +300,16 @@ static inline int hostapd_drv_br_delete_ip_neigh(struct hostapd_data *hapd,
 	return hapd->driver->br_delete_ip_neigh(hapd->drv_priv, ipaddr);
 }
 
+static inline int hostapd_drv_br_port_set_attr(struct hostapd_data *hapd,
+					       enum drv_br_port_attr attr,
+					       unsigned int val)
+{
+	if (hapd->driver == NULL || hapd->drv_priv == NULL ||
+	    hapd->driver->br_port_set_attr == NULL)
+		return -1;
+	return hapd->driver->br_port_set_attr(hapd->drv_priv, attr, val);
+}
+
 static inline int hostapd_drv_vendor_cmd(struct hostapd_data *hapd,
 					 int vendor_id, int subcmd,
 					 const u8 *data, size_t data_len,

src/drivers/driver.h

@@ -1373,6 +1373,11 @@ struct macsec_init_params {
 };
 #endif /* CONFIG_MACSEC */
 
+enum drv_br_port_attr {
+	DRV_BR_PORT_ATTR_PROXYARP,
+	DRV_BR_PORT_ATTR_HAIRPIN_MODE,
+};
+
 
 /**
  * struct wpa_driver_ops - Driver interface API definition
@@ -2619,6 +2624,15 @@ struct wpa_driver_ops {
 	 */
 	int (*br_delete_ip_neigh)(void *priv, be32 ipaddr);
 
+	/**
+	 * br_port_set_attr - Set a bridge port attribute
+	 * @attr: Bridge port attribute to set
+	 * @val: Value to be set
+	 * Returns: 0 on success, negative (<0) on failure
+	 */
+	int (*br_port_set_attr)(void *priv, enum drv_br_port_attr attr,
+				unsigned int val);
+
 	/**
 	 * set_wowlan - Set wake-on-wireless triggers
 	 * @priv: Private driver interface data

src/drivers/driver_nl80211.c

@@ -12,6 +12,7 @@
 
 #include "includes.h"
 #include <sys/types.h>
+#include <fcntl.h>
 #include <net/if.h>
 #include <netlink/genl/genl.h>
 #include <netlink/genl/ctrl.h>
@@ -8974,6 +8975,66 @@ errout:
 }
 
 
+static int linux_write_system_file(const char *path, unsigned int val)
+{
+	char buf[50];
+	int fd, len;
+
+	len = os_snprintf(buf, sizeof(buf), "%u\n", val);
+	if (len < 0)
+		return -1;
+
+	fd = open(path, O_WRONLY);
+	if (fd < 0)
+		return -1;
+
+	if (write(fd, buf, len) < 0) {
+		wpa_printf(MSG_DEBUG,
+			   "nl80211: Failed to write Linux system file: %s with the value of %d",
+			   path, val);
+		close(fd);
+		return -1;
+	}
+	close(fd);
+
+	return 0;
+}
+
+
+static const char * drv_br_port_attr_str(enum drv_br_port_attr attr)
+{
+	switch (attr) {
+	case DRV_BR_PORT_ATTR_PROXYARP:
+		return "proxyarp";
+	case DRV_BR_PORT_ATTR_HAIRPIN_MODE:
+		return "hairpin_mode";
+	}
+
+	return NULL;
+}
+
+
+static int wpa_driver_br_port_set_attr(void *priv, enum drv_br_port_attr attr,
+				       unsigned int val)
+{
+	struct i802_bss *bss = priv;
+	char path[128];
+	const char *attr_txt;
+
+	attr_txt = drv_br_port_attr_str(attr);
+	if (attr_txt == NULL)
+		return -EINVAL;
+
+	os_snprintf(path, sizeof(path), "/sys/class/net/%s/brport/%s",
+		    bss->ifname, attr_txt);
+
+	if (linux_write_system_file(path, val))
+		return -1;
+
+	return 0;
+}
+
+
 const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.name = "nl80211",
 	.desc = "Linux nl80211/cfg80211",
@@ -9074,4 +9135,5 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 #endif /* CONFIG_MESH */
 	.br_add_ip_neigh = wpa_driver_br_add_ip_neigh,
 	.br_delete_ip_neigh = wpa_driver_br_delete_ip_neigh,
+	.br_port_set_attr = wpa_driver_br_port_set_attr,
 };