path: root/net/mac80211/iface.c

/*
 * Interface handling (except master interface)
 *
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
 * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "debugfs_netdev.h"
#include "mesh.h"
#include "led.h"
#include "driver-ops.h"

/**
 * DOC: Interface list locking
 *
 * The interface list in each struct ieee80211_local is protected
 * three-fold:
 *
 * (1) modifications may only be done under the RTNL
 * (2) modifications and readers are protected against each other by
 *     the iflist_mtx.
 * (3) modifications are done in an RCU manner so atomic readers
 *     can traverse the list in RCU-safe blocks.
 *
 * As a consequence, reads (traversals) of the list can be protected
 * by either the RTNL, the iflist_mtx or RCU.
 */


static int ieee80211_change_mtu(struct net_device *dev, int new_mtu)
{
	int meshhdrlen;
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	meshhdrlen = (sdata->vif.type == NL80211_IFTYPE_MESH_POINT) ? 5 : 0;

	/* FIX: what would be proper limits for MTU?
	 * This interface uses 802.3 frames. */
	if (new_mtu < 256 ||
	    new_mtu > IEEE80211_MAX_DATA_LEN - 24 - 6 - meshhdrlen) {
		return -EINVAL;
	}

#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	printk(KERN_DEBUG "%s: setting MTU %d\n", dev->name, new_mtu);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
	dev->mtu = new_mtu;
	return 0;
}

static inline int identical_mac_addr_allowed(int type1, int type2)
{
	return type1 == NL80211_IFTYPE_MONITOR ||
		type2 == NL80211_IFTYPE_MONITOR ||
		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_WDS) ||
		(type1 == NL80211_IFTYPE_WDS &&
			(type2 == NL80211_IFTYPE_WDS ||
			 type2 == NL80211_IFTYPE_AP)) ||
		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_AP_VLAN) ||
		(type1 == NL80211_IFTYPE_AP_VLAN &&
			(type2 == NL80211_IFTYPE_AP ||
			 type2 == NL80211_IFTYPE_AP_VLAN));
}

static int ieee80211_open(struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_sub_if_data *nsdata;
	struct ieee80211_local *local = sdata->local;
	struct sta_info *sta;
	struct ieee80211_if_init_conf conf;
	u32 changed = 0;
	int res;
	u32 hw_reconf_flags = 0;
	u8 null_addr[ETH_ALEN] = {0};

	/* fail early if user set an invalid address */
	if (compare_ether_addr(dev->dev_addr, null_addr) &&
	    !is_valid_ether_addr(dev->dev_addr))
		return -EADDRNOTAVAIL;

	/* we hold the RTNL here so can safely walk the list */
	list_for_each_entry(nsdata, &local->interfaces, list) {
		struct net_device *ndev = nsdata->dev;

		if (ndev != dev && netif_running(ndev)) {
			/*
			 * Allow only a single IBSS interface to be up at any
			 * time. This is restricted because beacon distribution
			 * cannot work properly if both are in the same IBSS.
			 *
			 * To remove this restriction we'd have to disallow them
			 * from setting the same SSID on different IBSS interfaces
			 * belonging to the same hardware. Then, however, we're
			 * faced with having to adopt two different TSF timers...
			 */
			if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
			    nsdata->vif.type == NL80211_IFTYPE_ADHOC)
				return -EBUSY;

			/*
			 * The remaining checks are only performed for interfaces
			 * with the same MAC address.
			 */
			if (compare_ether_addr(dev->dev_addr, ndev->dev_addr))
				continue;

			/*
			 * check whether it may have the same address
			 */
			if (!identical_mac_addr_allowed(sdata->vif.type,
							nsdata->vif.type))
				return -ENOTUNIQ;

			/*
			 * can only add VLANs to enabled APs
			 */
			if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
			    nsdata->vif.type == NL80211_IFTYPE_AP)
				sdata->bss = &nsdata->u.ap;
		}
	}

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_WDS:
		if (!is_valid_ether_addr(sdata->u.wds.remote_addr))
			return -ENOLINK;
		break;
	case NL80211_IFTYPE_AP_VLAN:
		if (!sdata->bss)
			return -ENOLINK;
		list_add(&sdata->u.vlan.list, &sdata->bss->vlans);
		break;
	case NL80211_IFTYPE_AP:
		sdata->bss = &sdata->u.ap;
		break;
	case NL80211_IFTYPE_MESH_POINT:
		if (!ieee80211_vif_is_mesh(&sdata->vif))
			break;
		/* mesh ifaces must set allmulti to forward mcast traffic */
		atomic_inc(&local->iff_allmultis);
		break;
	case NL80211_IFTYPE_STATION:
	case NL80211_IFTYPE_MONITOR:
	case NL80211_IFTYPE_ADHOC:
		/* no special treatment */
		break;
	case NL80211_IFTYPE_UNSPECIFIED:
	case __NL80211_IFTYPE_AFTER_LAST:
		/* cannot happen */
		WARN_ON(1);