AP MLD: Create link based hostapd control sockets

Create link based control sockets to access the link based commands
through hostapd_cli. This will create the link interfaces in the name of
<ifname>_link<X>

Example:
To fetch link 0 status from wlan0, below command can be used -
    $ hostapd_cli -i wlan0 -l 0 status

On failure of link/interface selection, below error will be observed
    $ hostapd_cli -i wlan0 -l 2 status
    Failed to connect to hostapd - wpa_ctrl_open: No such file or directory

Signed-off-by: Karthikeyan Kathirvel <quic_kathirve@quicinc.com>
Co-developed-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>

hostapd/ctrl_iface.c

@@ -4739,18 +4739,26 @@ static char * hostapd_ctrl_iface_path(struct hostapd_data *hapd)
 {
 	char *buf;
 	size_t len;
+	const char *ctrl_sock_iface;
+
+#ifdef CONFIG_IEEE80211BE
+	ctrl_sock_iface = hapd->ctrl_sock_iface;
+#else /* CONFIG_IEEE80211BE */
+	ctrl_sock_iface = hapd->conf->iface;
+#endif /* CONFIG_IEEE80211BE */
 
 	if (hapd->conf->ctrl_interface == NULL)
 		return NULL;
 
 	len = os_strlen(hapd->conf->ctrl_interface) +
-		os_strlen(hapd->conf->iface) + 2;
+		os_strlen(ctrl_sock_iface) + 2;
+
 	buf = os_malloc(len);
 	if (buf == NULL)
 		return NULL;
 
 	os_snprintf(buf, len, "%s/%s",
-		    hapd->conf->ctrl_interface, hapd->conf->iface);
+		    hapd->conf->ctrl_interface, ctrl_sock_iface);
 	buf[len - 1] = '\0';
 	return buf;
 }
@@ -4866,6 +4874,7 @@ fail:
 	struct sockaddr_un addr;
 	int s = -1;
 	char *fname = NULL;
+	size_t iflen;
 
 	if (hapd->ctrl_sock > -1) {
 		wpa_printf(MSG_DEBUG, "ctrl_iface already exists!");
@@ -4920,8 +4929,13 @@ fail:
 	}
 #endif /* ANDROID */
 
+#ifdef CONFIG_IEEE80211BE
+	iflen = os_strlen(hapd->ctrl_sock_iface);
+#else /* CONFIG_IEEE80211BE */
+	iflen = os_strlen(hapd->conf->iface);
+#endif /* CONFIG_IEEE80211BE */
 	if (os_strlen(hapd->conf->ctrl_interface) + 1 +
-	    os_strlen(hapd->conf->iface) >= sizeof(addr.sun_path))
+	    iflen >= sizeof(addr.sun_path))
 		goto fail;
 
 	s = socket(PF_UNIX, SOCK_DGRAM, 0);

hostapd/hostapd_cli.c

@@ -54,7 +54,11 @@ static void usage(void)
 	fprintf(stderr, "%s\n", hostapd_cli_version);
 	fprintf(stderr,
 		"\n"
-		"usage: hostapd_cli [-p<path>] [-i<ifname>] [-hvBr] "
+		"usage: hostapd_cli [-p<path>] [-i<ifname>] "
+#ifdef CONFIG_IEEE80211BE
+		"[-l<link_id>] "
+#endif /* CONFIG_IEEE80211BE */
+		"[-hvBr] "
 		"[-a<path>] \\\n"
 		"                   [-P<pid file>] [-G<ping interval>] [command..]\n"
 		"\n"
@@ -74,7 +78,11 @@ static void usage(void)
 		"   -B           run a daemon in the background\n"
 		"   -i<ifname>   Interface to listen on (default: first "
 		"interface found in the\n"
-		"                socket path)\n\n");
+		"                socket path)\n"
+#ifdef CONFIG_IEEE80211BE
+		"   -l<link_id>  Link ID of the interface in case of Multi-Link Operation\n"
+#endif /* CONFIG_IEEE80211BE */
+		"\n");
 	print_help(stderr, NULL);
 }
 
@@ -2212,12 +2220,15 @@ int main(int argc, char *argv[])
 	int c;
 	int daemonize = 0;
 	int reconnect = 0;
+#ifdef CONFIG_IEEE80211BE
+	int link_id = -1;
+#endif /* CONFIG_IEEE80211BE */
 
 	if (os_program_init())
 		return -1;
 
 	for (;;) {
-		c = getopt(argc, argv, "a:BhG:i:p:P:rs:v");
+		c = getopt(argc, argv, "a:BhG:i:l:p:P:rs:v");
 		if (c < 0)
 			break;
 		switch (c) {
@@ -2252,6 +2263,11 @@ int main(int argc, char *argv[])
 		case 's':
 			client_socket_dir = optarg;
 			break;
+#ifdef CONFIG_IEEE80211BE
+		case 'l':
+			link_id = atoi(optarg);
+			break;
+#endif /* CONFIG_IEEE80211BE */
 		default:
 			usage();
 			return -1;
@@ -2285,6 +2301,24 @@ int main(int argc, char *argv[])
 				closedir(dir);
 			}
 		}
+
+#ifdef CONFIG_IEEE80211BE
+		if (link_id >= 0 && ctrl_ifname) {
+			int ret;
+			char buf[300];
+
+			ret = os_snprintf(buf, sizeof(buf), "%s_%s%d",
+					  ctrl_ifname, WPA_CTRL_IFACE_LINK_NAME,
+					  link_id);
+			if (os_snprintf_error(sizeof(buf), ret))
+				return -1;
+
+			os_free(ctrl_ifname);
+			ctrl_ifname = os_strdup(buf);
+			link_id = -1;
+		}
+#endif /* CONFIG_IEEE80211BE */
+
 		hostapd_cli_reconnect(ctrl_ifname);
 		if (ctrl_conn) {
 			if (warning_displayed)

src/ap/hostapd.c

@@ -1824,12 +1824,36 @@ int hostapd_set_acl(struct hostapd_data *hapd)
 }
 
 
+static int hostapd_set_ctrl_sock_iface(struct hostapd_data *hapd)
+{
+#ifdef CONFIG_IEEE80211BE
+	int ret;
+
+	if (hapd->conf->mld_ap) {
+		ret = os_snprintf(hapd->ctrl_sock_iface,
+				  sizeof(hapd->ctrl_sock_iface), "%s_%s%d",
+				  hapd->conf->iface, WPA_CTRL_IFACE_LINK_NAME,
+				  hapd->mld_link_id);
+		if (os_snprintf_error(sizeof(hapd->ctrl_sock_iface), ret))
+			return -1;
+	} else {
+		os_strlcpy(hapd->ctrl_sock_iface, hapd->conf->iface,
+			   sizeof(hapd->ctrl_sock_iface));
+	}
+#endif /* CONFIG_IEEE80211BE */
+	return 0;
+}
+
+
 static int start_ctrl_iface_bss(struct hostapd_data *hapd)
 {
 	if (!hapd->iface->interfaces ||
 	    !hapd->iface->interfaces->ctrl_iface_init)
 		return 0;
 
+	if (hostapd_set_ctrl_sock_iface(hapd))
+		return -1;
+
 	if (hapd->iface->interfaces->ctrl_iface_init(hapd)) {
 		wpa_printf(MSG_ERROR,
 			   "Failed to setup control interface for %s",
@@ -1850,6 +1874,10 @@ static int start_ctrl_iface(struct hostapd_iface *iface)
 
 	for (i = 0; i < iface->num_bss; i++) {
 		struct hostapd_data *hapd = iface->bss[i];
+
+		if (hostapd_set_ctrl_sock_iface(hapd))
+			return -1;
+
 		if (iface->interfaces->ctrl_iface_init(hapd)) {
 			wpa_printf(MSG_ERROR,
 				   "Failed to setup control interface for %s",

src/ap/hostapd.h

@@ -495,6 +495,10 @@ struct hostapd_data {
 	/* Cached partner info for ML probe response */
 	struct mld_link_info partner_links[MAX_NUM_MLD_LINKS];
 
+	/* 5 characters for "_link", up to 2 characters for <link ID>, so in
+	 * total, additional 7 characters required. */
+	char ctrl_sock_iface[IFNAMSIZ + 7 + 1];
+
 #ifdef CONFIG_TESTING_OPTIONS
 	u8 eht_mld_link_removal_count;
 #endif /* CONFIG_TESTING_OPTIONS */

src/common/wpa_ctrl.h

@@ -13,6 +13,8 @@
 extern "C" {
 #endif
 
+#define WPA_CTRL_IFACE_LINK_NAME	"link"
+
 /* wpa_supplicant control interface - fixed message prefixes */
 
 /** Interactive request for identity/password/pin */