Add option to use netlink to create and remove VLAN interfaces

CONFIG_VLAN_NETLINK=y build option can now be used to replace the
ioctl()-based interface for creating and removing VLAN interfaces
with netlink-based interface.

Signed-hostap: M. Braun <michael-dev@fami-braun.de>

hostapd/Android.mk

@@ -151,6 +151,12 @@ ifdef CONFIG_NO_VLAN
 L_CFLAGS += -DCONFIG_NO_VLAN
 else
 OBJS += src/ap/vlan_init.c
+ifdef CONFIG_VLAN_NETLINK
+ifdef CONFIG_FULL_DYNAMIC_VLAN
+OBJS += src/ap/vlan_util.c
+endif
+L_CFLAGS += -DCONFIG_VLAN_NETLINK
+endif
 endif
 
 ifdef CONFIG_NO_CTRL_IFACE

hostapd/Makefile

@@ -123,6 +123,12 @@ ifdef CONFIG_NO_VLAN
 CFLAGS += -DCONFIG_NO_VLAN
 else
 OBJS += ../src/ap/vlan_init.o
+ifdef CONFIG_VLAN_NETLINK
+ifdef CONFIG_FULL_DYNAMIC_VLAN
+OBJS += ../src/ap/vlan_util.o
+endif
+CFLAGS += -DCONFIG_VLAN_NETLINK
+endif
 endif
 
 ifdef CONFIG_NO_CTRL_IFACE

hostapd/defconfig

@@ -167,6 +167,10 @@ CONFIG_IPV6=y
 # automatically create bridge and VLAN interfaces if necessary.
 #CONFIG_FULL_DYNAMIC_VLAN=y
 
+# Use netlink-based kernel API for VLAN operations instead of ioctl()
+# Note: This requires libnl 3.1 or newer.
+#CONFIG_VLAN_NETLINK=y
+
 # Remove support for dumping state into a file on SIGUSR1 signal
 # This can be used to reduce binary size at the cost of disabling a debugging
 # option.

src/ap/vlan_init.c

@@ -21,6 +21,7 @@
 #include "ap_config.h"
 #include "ap_drv_ops.h"
 #include "vlan_init.h"
+#include "vlan_util.h"
 
 
 #ifdef CONFIG_FULL_DYNAMIC_VLAN
@@ -335,7 +336,9 @@ static int br_getnumports(const char *br_name)
 }
 
 
-static int vlan_rem(const char *if_name)
+#ifndef CONFIG_VLAN_NETLINK
+
+int vlan_rem(const char *if_name)
 {
 	int fd;
 	struct vlan_ioctl_args if_request;
@@ -378,7 +381,7 @@ static int vlan_rem(const char *if_name)
 	returns 1 if the interface already exists
 	returns 0 otherwise
 */
-static int vlan_add(const char *if_name, int vid)
+int vlan_add(const char *if_name, int vid, const char *vlan_if_name)
 {
 	int fd;
 	struct vlan_ioctl_args if_request;
@@ -474,6 +477,8 @@ static int vlan_set_name_type(unsigned int name_type)
 	return 0;
 }
 
+#endif /* CONFIG_VLAN_NETLINK */
+
 
 static void vlan_newlink(char *ifname, struct hostapd_data *hapd)
 {
@@ -509,7 +514,8 @@ static void vlan_newlink(char *ifname, struct hostapd_data *hapd)
 						    "vlan%d", vlan->vlan_id);
 
 				ifconfig_up(tagged_interface);
-				if (!vlan_add(tagged_interface, vlan->vlan_id))
+				if (!vlan_add(tagged_interface, vlan->vlan_id,
+					      vlan_ifname))
 					vlan->clean |= DVLAN_CLEAN_VLAN;
 
 				if (!br_addif(br_name, vlan_ifname))
@@ -700,10 +706,12 @@ full_dynamic_vlan_init(struct hostapd_data *hapd)
 	if (priv == NULL)
 		return NULL;
 
+#ifndef CONFIG_VLAN_NETLINK
 	vlan_set_name_type(hapd->conf->ssid.vlan_naming ==
 			   DYNAMIC_VLAN_NAMING_WITH_DEVICE ?
 			   VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD :
 			   VLAN_NAME_TYPE_PLUS_VID_NO_PAD);
+#endif /* CONFIG_VLAN_NETLINK */
 
 	priv->s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 	if (priv->s < 0) {

src/ap/vlan_util.c

@@ -0,0 +1,177 @@
+/*
+ * hostapd / VLAN netlink api
+ * Copyright (c) 2012, Michael Braun <michael-dev@fami-braun.de>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+#include <sys/ioctl.h>
+#include <linux/sockios.h>
+#include <linux/if_vlan.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/family.h>
+#include <netlink/genl/ctrl.h>
+#include <netlink/route/link.h>
+#include <netlink/route/link/vlan.h>
+
+#include "utils/common.h"
+#include "utils/eloop.h"
+#include "hostapd.h"
+#include "vlan_util.h"
+
+/*
+ * Add a vlan interface with name 'vlan_if_name', VLAN ID 'vid' and
+ * tagged interface 'if_name'.
+ *
+ * returns -1 on error
+ * returns 1 if the interface already exists
+ * returns 0 otherwise
+*/
+int vlan_add(const char *if_name, int vid, const char *vlan_if_name)
+{
+	int ret = -1;
+	struct nl_sock *handle = NULL;
+	struct nl_cache *cache = NULL;
+	struct rtnl_link *rlink = NULL;
+	int if_idx = 0;
+
+	wpa_printf(MSG_DEBUG, "VLAN: vlan_add(if_name=%s, vid=%d, "
+		   "vlan_if_name=%s)", if_name, vid, vlan_if_name);
+
+	if ((os_strlen(if_name) + 1) > IFNAMSIZ) {
+		wpa_printf(MSG_ERROR, "VLAN: Interface name too long: '%s'",
+			   if_name);
+		return -1;
+	}
+
+	if ((os_strlen(vlan_if_name) + 1) > IFNAMSIZ) {
+		wpa_printf(MSG_ERROR, "VLAN: Interface name too long: '%s'",
+			   vlan_if_name);
+		return -1;
+	}
+
+	handle = nl_socket_alloc();
+	if (!handle) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to open netlink socket");
+		goto vlan_add_error;
+	}
+
+	if (nl_connect(handle, NETLINK_ROUTE) < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to connect to netlink");
+		goto vlan_add_error;
+	}
+
+	if (rtnl_link_alloc_cache(handle, AF_UNSPEC, &cache) < 0) {
+		cache = NULL;
+		wpa_printf(MSG_ERROR, "VLAN: failed to alloc cache");
+		goto vlan_add_error;
+	}
+
+	if (!(if_idx = rtnl_link_name2i(cache, if_name))) {
+		/* link does not exist */
+		wpa_printf(MSG_ERROR, "VLAN: interface %s does not exist",
+			   if_name);
+		goto vlan_add_error;
+	}
+
+	if ((rlink = rtnl_link_get_by_name(cache, vlan_if_name))) {
+		/* link does exist */
+		rtnl_link_put(rlink);
+		rlink = NULL;
+		wpa_printf(MSG_ERROR, "VLAN: interface %s already exists",
+			   vlan_if_name);
+		ret = 1;
+		goto vlan_add_error;
+	}
+
+	rlink = rtnl_link_alloc();
+	if (!rlink) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to allocate new link");
+		goto vlan_add_error;
+	}
+
+	if (rtnl_link_set_type(rlink, "vlan") < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to set link type");
+		goto vlan_add_error;
+	}
+
+	rtnl_link_set_link(rlink, if_idx);
+	rtnl_link_set_name(rlink, vlan_if_name);
+
+	if (rtnl_link_vlan_set_id(rlink, vid) < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to set link vlan id");
+		goto vlan_add_error;
+	}
+
+	if (rtnl_link_add(handle, rlink, NLM_F_CREATE) < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to create link %s for "
+			   "vlan %d on %s (%d)",
+			   vlan_if_name, vid, if_name, if_idx);
+		goto vlan_add_error;
+	}
+
+	ret = 0;
+
+vlan_add_error:
+	if (rlink)
+		rtnl_link_put(rlink);
+	if (cache)
+		nl_cache_free(cache);
+	if (handle)
+		nl_socket_free(handle);
+	return ret;
+}
+
+
+int vlan_rem(const char *if_name)
+{
+	int ret = -1;
+	struct nl_sock *handle = NULL;
+	struct nl_cache *cache = NULL;
+	struct rtnl_link *rlink = NULL;
+
+	wpa_printf(MSG_DEBUG, "VLAN: vlan_rem(if_name=%s)", if_name);
+
+	handle = nl_socket_alloc();
+	if (!handle) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to open netlink socket");
+		goto vlan_rem_error;
+	}
+
+	if (nl_connect(handle, NETLINK_ROUTE) < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to connect to netlink");
+		goto vlan_rem_error;
+	}
+
+	if (rtnl_link_alloc_cache(handle, AF_UNSPEC, &cache) < 0) {
+		cache = NULL;
+		wpa_printf(MSG_ERROR, "VLAN: failed to alloc cache");
+		goto vlan_rem_error;
+	}
+
+	if (!(rlink = rtnl_link_get_by_name(cache, if_name))) {
+		/* link does not exist */
+		wpa_printf(MSG_ERROR, "VLAN: interface %s does not exists",
+			   if_name);
+		goto vlan_rem_error;
+	}
+
+	if (rtnl_link_delete(handle, rlink) < 0) {
+		wpa_printf(MSG_ERROR, "VLAN: failed to remove link %s",
+			   if_name);
+		goto vlan_rem_error;
+	}
+
+	ret = 0;
+
+vlan_rem_error:
+	if (rlink)
+		rtnl_link_put(rlink);
+	if (cache)
+		nl_cache_free(cache);
+	if (handle)
+		nl_socket_free(handle);
+	return ret;
+}

src/ap/vlan_util.h

@@ -0,0 +1,15 @@
+/*
+ * hostapd / VLAN netlink api
+ * Copyright (c) 2012, Michael Braun <michael-dev@fami-braun.de>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#ifndef VLAN_UTIL_H
+#define VLAN_UTIL_H
+
+int vlan_add(const char *if_name, int vid, const char *vlan_if_name);
+int vlan_rem(const char *if_name);
+
+#endif /* VLAN_UTIL_H */

src/drivers/drivers.mak

@@ -142,6 +142,28 @@ ifdef NEED_RFKILL
 DRV_OBJS += ../src/drivers/rfkill.o
 endif
 
+ifdef CONFIG_VLAN_NETLINK
+ifdef CONFIG_FULL_DYNAMIC_VLAN
+ifdef CONFIG_LIBNL32
+  DRV_LIBS += -lnl-3
+  DRV_LIBS += -lnl-genl-3
+  DRV_LIBS += -lnl-route-3
+  DRV_CFLAGS += -DCONFIG_LIBNL20
+else
+  ifdef CONFIG_LIBNL_TINY
+    DRV_LIBS += -lnl-tiny
+  else
+    DRV_LIBS += -lnl
+  endif
+
+  ifdef CONFIG_LIBNL20
+    DRV_LIBS += -lnl-genl
+    DRV_LIBS += -lnl-route
+    DRV_CFLAGS += -DCONFIG_LIBNL20
+  endif
+endif
+endif
+endif
 
 ##### COMMON VARS
 DRV_BOTH_CFLAGS := $(DRV_CFLAGS) $(DRV_WPA_CFLAGS) $(DRV_AP_CFLAGS)

src/drivers/drivers.mk

@@ -146,6 +146,29 @@ ifdef CONFIG_DRIVER_CUSTOM
 DRV_CFLAGS += -DCONFIG_DRIVER_CUSTOM
 endif
 
+ifdef CONFIG_VLAN_NETLINK
+ifdef CONFIG_FULL_DYNAMIC_VLAN
+ifdef CONFIG_LIBNL32
+  DRV_LIBS += -lnl-3
+  DRV_LIBS += -lnl-genl-3
+  DRV_LIBS += -lnl-route-3
+  DRV_CFLAGS += -DCONFIG_LIBNL20
+else
+  ifdef CONFIG_LIBNL_TINY
+    DRV_LIBS += -lnl-tiny
+  else
+    DRV_LIBS += -lnl
+  endif
+
+  ifdef CONFIG_LIBNL20
+    DRV_LIBS += -lnl-genl
+    DRV_LIBS += -lnl-route
+    DRV_CFLAGS += -DCONFIG_LIBNL20
+  endif
+endif
+endif
+endif
+
 ##### COMMON VARS
 DRV_BOTH_CFLAGS := $(DRV_CFLAGS) $(DRV_WPA_CFLAGS) $(DRV_AP_CFLAGS)
 DRV_WPA_CFLAGS += $(DRV_CFLAGS)