core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * This is the linux wireless configuration interface.
 *
 * Copyright 2006-2010		Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 * Copyright 2015-2017	Intel Deutschland GmbH
 * Copyright (C) 2018-2020 Intel Corporation
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/if.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/nl80211.h>
#include <linux/debugfs.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <net/genetlink.h>
#include <net/cfg80211.h>
#include "nl80211.h"
#include "core.h"
#include "sysfs.h"
#include "debugfs.h"
#include "wext-compat.h"
#include "rdev-ops.h"

/* name for sysfs, %d is appended */
#define PHY_NAME "phy"

MODULE_AUTHOR("Johannes Berg");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("wireless configuration support");
MODULE_ALIAS_GENL_FAMILY(NL80211_GENL_NAME);

/* RCU-protected (and RTNL for writers) */
LIST_HEAD(cfg80211_rdev_list);
int cfg80211_rdev_list_generation;

/* for debugfs */
static struct dentry *ieee80211_debugfs_dir;

/* for the cleanup, scan and event works */
struct workqueue_struct *cfg80211_wq;

static bool cfg80211_disable_40mhz_24ghz;
module_param(cfg80211_disable_40mhz_24ghz, bool, 0644);
MODULE_PARM_DESC(cfg80211_disable_40mhz_24ghz,
		 "Disable 40MHz support in the 2.4GHz band");

struct cfg80211_registered_device *cfg80211_rdev_by_wiphy_idx(int wiphy_idx)
{
	struct cfg80211_registered_device *result = NULL, *rdev;

	ASSERT_RTNL();

	list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
		if (rdev->wiphy_idx == wiphy_idx) {
			result = rdev;
			break;
		}
	}

	return result;
}

int get_wiphy_idx(struct wiphy *wiphy)
{
	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);

	return rdev->wiphy_idx;
}

struct wiphy *wiphy_idx_to_wiphy(int wiphy_idx)
{
	struct cfg80211_registered_device *rdev;

	ASSERT_RTNL();

	rdev = cfg80211_rdev_by_wiphy_idx(wiphy_idx);
	if (!rdev)
		return NULL;
	return &rdev->wiphy;
}

static int cfg80211_dev_check_name(struct cfg80211_registered_device *rdev,
				   const char *newname)
{
	struct cfg80211_registered_device *rdev2;
	int wiphy_idx, taken = -1, digits;

	ASSERT_RTNL();

	if (strlen(newname) > NL80211_WIPHY_NAME_MAXLEN)
		return -EINVAL;

	/* prohibit calling the thing phy%d when %d is not its number */
	sscanf(newname, PHY_NAME "%d%n", &wiphy_idx, &taken);
	if (taken == strlen(newname) && wiphy_idx != rdev->wiphy_idx) {
		/* count number of places needed to print wiphy_idx */
		digits = 1;
		while (wiphy_idx /= 10)
			digits++;
		/*
		 * deny the name if it is phy<idx> where <idx> is printed
		 * without leading zeroes. taken == strlen(newname) here
		 */
		if (taken == strlen(PHY_NAME) + digits)
			return -EINVAL;
	}

	/* Ensure another device does not already have this name. */
	list_for_each_entry(rdev2, &cfg80211_rdev_list, list)
		if (strcmp(newname, wiphy_name(&rdev2->wiphy)) == 0)
			return -EINVAL;

	return 0;
}

int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
			char *newname)
{
	int result;

	ASSERT_RTNL();

	/* Ignore nop renames */
	if (strcmp(newname, wiphy_name(&rdev->wiphy)) == 0)
		return 0;

	result = cfg80211_dev_check_name(rdev, newname);
	if (result < 0)
		return result;

	result = device_rename(&rdev->wiphy.dev, newname);
	if (result)
		return result;

	if (!IS_ERR_OR_NULL(rdev->wiphy.debugfsdir))
		debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
			       rdev->wiphy.debugfsdir,
			       rdev->wiphy.debugfsdir->d_parent, newname);

	nl80211_notify_wiphy(rdev, NL80211_CMD_NEW_WIPHY);

	return 0;
}

int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
			  struct net *net)
{
	struct wireless_dev *wdev;
	int err = 0;

	if (!(rdev->wiphy.flags & WIPHY_FLAG_NETNS_OK))
		return -EOPNOTSUPP;

	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
		if (!wdev->netdev)
			continue;
		wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
		err = dev_change_net_namespace(wdev->netdev, net, "wlan%d");
		if (err)
			break;
		wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
	}

	if (err) {
		/* failed -- clean up to old netns */
		net = wiphy_net(&rdev->wiphy);

		list_for_each_entry_continue_reverse(wdev,
						     &rdev->wiphy.wdev_list,
						     list) {
			if (!wdev->netdev)
				continue;
			wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
			err = dev_change_net_namespace(wdev->netdev, net,
							"wlan%d");
			WARN_ON(err);
			wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
		}

		return err;
	}

	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
		if (!wdev->netdev)
			continue;
		nl80211_notify_iface(rdev, wdev, NL80211_CMD_DEL_INTERFACE);
	}
	nl80211_notify_wiphy(rdev, NL80211_CMD_DEL_WIPHY);

	wiphy_net_set(&rdev->wiphy, net);