From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 15 Dec 2022 13:57:04 +0100
Subject: [PATCH] hostapd: add support for automatically setting RADIUS own-ip
 dynamically

Some servers use the NAS-IP-Address attribute as a destination address

--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2632,6 +2632,8 @@ static int hostapd_config_fill(struct ho
 	} else if (os_strcmp(buf, "iapp_interface") == 0) {
 		wpa_printf(MSG_INFO, "DEPRECATED: iapp_interface not used");
 #endif /* CONFIG_IAPP */
+	} else if (os_strcmp(buf, "dynamic_own_ip_addr") == 0) {
+		bss->dynamic_own_ip_addr = atoi(pos);
 	} else if (os_strcmp(buf, "own_ip_addr") == 0) {
 		if (hostapd_parse_ip_addr(pos, &bss->own_ip_addr)) {
 			wpa_printf(MSG_ERROR,
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -312,6 +312,7 @@ struct hostapd_bss_config {
 	unsigned int eap_sim_db_timeout;
 	int eap_server_erp; /* Whether ERP is enabled on internal EAP server */
 	struct hostapd_ip_addr own_ip_addr;
+	int dynamic_own_ip_addr;
 	char *nas_identifier;
 	struct hostapd_radius_servers *radius;
 	int radius_require_message_authenticator;
--- a/src/ap/ieee802_1x.c
+++ b/src/ap/ieee802_1x.c
@@ -602,6 +602,10 @@ int add_common_radius_attr(struct hostap
 	struct hostapd_radius_attr *attr;
 	int len;
 
+	if (hapd->conf->dynamic_own_ip_addr)
+		radius_client_get_local_addr(hapd->radius,
+					     &hapd->conf->own_ip_addr);
+
 	if (!hostapd_config_get_radius_attr(req_attr,
 					    RADIUS_ATTR_NAS_IP_ADDRESS) &&
 	    hapd->conf->own_ip_addr.af == AF_INET &&
--- a/src/radius/radius_client.c
+++ b/src/radius/radius_client.c
@@ -165,6 +165,8 @@ struct radius_client_data {
 	 */
 	void *ctx;
 
+	struct hostapd_ip_addr local_ip;
+
 	/**
 	 * conf - RADIUS client configuration (list of RADIUS servers to use)
 	 */
@@ -822,6 +824,30 @@ static void radius_close_acct_socket(str
 
 
 /**
+ * radius_client_send - Get local address for the RADIUS auth socket
+ * @radius: RADIUS client context from radius_client_init()
+ * @addr: pointer to store the address
+ *
+ * This function returns the local address for the connection to the RADIUS
+ * auth server. It also opens the socket if it's not available yet.
+ */
+int radius_client_get_local_addr(struct radius_client_data *radius,
+				 struct hostapd_ip_addr *addr)
+{
+	struct hostapd_radius_servers *conf = radius->conf;
+
+	if (conf->auth_server && radius->auth_sock < 0)
+		radius_client_init_auth(radius);
+
+	if (radius->auth_sock < 0)
+		return -1;
+
+	memcpy(addr, &radius->local_ip, sizeof(*addr));
+
+	return 0;
+}
+
+/**
  * radius_client_send - Send a RADIUS request
  * @radius: RADIUS client context from radius_client_init()
  * @msg: RADIUS message to be sent
@@ -1733,6 +1759,10 @@ radius_change_server(struct radius_clien
 			wpa_printf(MSG_DEBUG, "RADIUS local address: %s:%u",
 				   inet_ntoa(claddr.sin_addr),
 				   ntohs(claddr.sin_port));
+			if (auth) {
+				radius->local_ip.af = AF_INET;
+				radius->local_ip.u.v4 = claddr.sin_addr;
+			}
 		}
 		break;
 #ifdef CONFIG_IPV6
@@ -1744,6 +1774,10 @@ radius_change_server(struct radius_clien
 				   inet_ntop(AF_INET6, &claddr6.sin6_addr,
 					     abuf, sizeof(abuf)),
 				   ntohs(claddr6.sin6_port));
+			if (auth) {
+				radius->local_ip.af = AF_INET6;
+				radius->local_ip.u.v6 = claddr6.sin6_addr;
+			}
 		}
 		break;
 	}
--- a/src/radius/radius_client.h
+++ b/src/radius/radius_client.h
@@ -274,6 +274,8 @@ int radius_client_register(struct radius
 void radius_client_set_interim_error_cb(struct radius_client_data *radius,
 					void (*cb)(const u8 *addr, void *ctx),
 					void *ctx);
+int radius_client_get_local_addr(struct radius_client_data *radius,
+				 struct hostapd_ip_addr * addr);
 int radius_client_send(struct radius_client_data *radius,
 		       struct radius_msg *msg,
 		       RadiusType msg_type, const u8 *addr);
