nl80211.c

/*
 * This is the new netlink-based wireless configuration interface.
 *
 * Copyright 2006, 2007	Johannes Berg <johannes@sipsolutions.net>
 */

#include <linux/if.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/if_ether.h>
#include <linux/ieee80211.h>
#include <linux/nl80211.h>
#include <linux/rtnetlink.h>
#include <linux/netlink.h>
#include <net/genetlink.h>
#include <net/cfg80211.h>
#include "core.h"
#include "nl80211.h"

/* the netlink family */
static struct genl_family nl80211_fam = {
	.id = GENL_ID_GENERATE,	/* don't bother with a hardcoded ID */
	.name = "nl80211",	/* have users key off the name instead */
	.hdrsize = 0,		/* no private header */
	.version = 1,		/* no particular meaning now */
	.maxattr = NL80211_ATTR_MAX,
};

/* internal helper: get drv and dev */
static int get_drv_dev_by_info_ifindex(struct genl_info *info,
				       struct cfg80211_registered_device **drv,
				       struct net_device **dev)
{
	int ifindex;

	if (!info->attrs[NL80211_ATTR_IFINDEX])
		return -EINVAL;

	ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
	*dev = dev_get_by_index(&init_net, ifindex);
	if (!*dev)
		return -ENODEV;

	*drv = cfg80211_get_dev_from_ifindex(ifindex);
	if (IS_ERR(*drv)) {
		dev_put(*dev);
		return PTR_ERR(*drv);
	}

	return 0;
}

/* policy for the attributes */
static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
	[NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
	[NL80211_ATTR_WIPHY_NAME] = { .type = NLA_NUL_STRING,
				      .len = BUS_ID_SIZE-1 },

	[NL80211_ATTR_IFTYPE] = { .type = NLA_U32 },
	[NL80211_ATTR_IFINDEX] = { .type = NLA_U32 },
	[NL80211_ATTR_IFNAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ-1 },
};

/* message building helper */
static inline void *nl80211hdr_put(struct sk_buff *skb, u32 pid, u32 seq,
				   int flags, u8 cmd)
{
	/* since there is no private header just add the generic one */
	return genlmsg_put(skb, pid, seq, &nl80211_fam, flags, cmd);
}

/* netlink command implementations */

static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
			      struct cfg80211_registered_device *dev)
{
	void *hdr;

	hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_WIPHY);
	if (!hdr)
		return -1;

	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, dev->idx);
	NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
	return genlmsg_end(msg, hdr);

 nla_put_failure:
	return genlmsg_cancel(msg, hdr);
}

static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
{
	int idx = 0;
	int start = cb->args[0];
	struct cfg80211_registered_device *dev;

	mutex_lock(&cfg80211_drv_mutex);
	list_for_each_entry(dev, &cfg80211_drv_list, list) {
		if (++idx < start)
			continue;
		if (nl80211_send_wiphy(skb, NETLINK_CB(cb->skb).pid,
				       cb->nlh->nlmsg_seq, NLM_F_MULTI,
				       dev) < 0)
			break;
	}
	mutex_unlock(&cfg80211_drv_mutex);

	cb->args[0] = idx;

	return skb->len;
}

static int nl80211_get_wiphy(struct sk_buff *skb, struct genl_info *info)
{
	struct sk_buff *msg;
	struct cfg80211_registered_device *dev;

	dev = cfg80211_get_dev_from_info(info);
	if (IS_ERR(dev))
		return PTR_ERR(dev);

	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!msg)
		goto out_err;

	if (nl80211_send_wiphy(msg, info->snd_pid, info->snd_seq, 0, dev) < 0)
		goto out_free;

	cfg80211_put_dev(dev);

	return genlmsg_unicast(msg, info->snd_pid);

 out_free:
	nlmsg_free(msg);
 out_err:
	cfg80211_put_dev(dev);
	return -ENOBUFS;
}

static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *rdev;
	int result;

	if (!info->attrs[NL80211_ATTR_WIPHY_NAME])
		return -EINVAL;

	rdev = cfg80211_get_dev_from_info(info);
	if (IS_ERR(rdev))
		return PTR_ERR(rdev);

	result = cfg80211_dev_rename(rdev, nla_data(info->attrs[NL80211_ATTR_WIPHY_NAME]));

	cfg80211_put_dev(rdev);
	return result;
}


static int nl80211_send_iface(struct sk_buff *msg, u32 pid, u32 seq, int flags,
			      struct net_device *dev)
{
	void *hdr;

	hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_INTERFACE);
	if (!hdr)
		return -1;

	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, dev->ifindex);
	NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, dev->name);
	/* TODO: interface type */
	return genlmsg_end(msg, hdr);

 nla_put_failure:
	return genlmsg_cancel(msg, hdr);
}

static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *cb)
{
	int wp_idx = 0;
	int if_idx = 0;
	int wp_start = cb->args[0];
	int if_start = cb->args[1];
	struct cfg80211_registered_device *dev;
	struct wireless_dev *wdev;

	mutex_lock(&cfg80211_drv_mutex);
	list_for_each_entry(dev, &cfg80211_drv_list, list) {
		if (++wp_idx < wp_start)
			continue;
		if_idx = 0;

		mutex_lock(&dev->devlist_mtx);
		list_for_each_entry(wdev, &dev->netdev_list, list) {
			if (++if_idx < if_start)
				continue;
			if (nl80211_send_iface(skb, NETLINK_CB(cb->skb).pid,
					       cb->nlh->nlmsg_seq, NLM_F_MULTI,
					       wdev->netdev) < 0)
				break;
		}
		mutex_unlock(&dev->devlist_mtx);
	}
	mutex_unlock(&cfg80211_drv_mutex);

	cb->args[0] = wp_idx;
	cb->args[1] = if_idx;

	return skb->len;
}

static int nl80211_get_interface(struct sk_buff *skb, struct genl_info *info)
{
	struct sk_buff *msg;
	struct cfg80211_registered_device *dev;
	struct net_device *netdev;
	int err;

	err = get_drv_dev_by_info_ifindex(info, &dev, &netdev);
	if (err)
		return err;

	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!msg)
		goto out_err;

	if (nl80211_send_iface(msg, info->snd_pid, info->snd_seq, 0, netdev) < 0)
		goto out_free;

	dev_put(netdev);
	cfg80211_put_dev(dev);

	return genlmsg_unicast(msg, info->snd_pid);

 out_free:
	nlmsg_free(msg);
 out_err:
	dev_put(netdev);
	cfg80211_put_dev(dev);
	return -ENOBUFS;
}

static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *drv;
	int err, ifindex;
	enum nl80211_iftype type;
	struct net_device *dev;

	if (info->attrs[NL80211_ATTR_IFTYPE]) {
		type = nla_get_u32(info->attrs[NL80211_ATTR_IFTYPE]);
		if (type > NL80211_IFTYPE_MAX)
			return -EINVAL;
	} else
		return -EINVAL;

	err = get_drv_dev_by_info_ifindex(info, &drv, &dev);
	if (err)
		return err;
	ifindex = dev->ifindex;
	dev_put(dev);

	if (!drv->ops->change_virtual_intf) {
		err = -EOPNOTSUPP;
		goto unlock;
	}

	rtnl_lock();
	err = drv->ops->change_virtual_intf(&drv->wiphy, ifindex, type);
	rtnl_unlock();

 unlock:
	cfg80211_put_dev(drv);
	return err;
}

static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *drv;
	int err;
	enum nl80211_iftype type = NL80211_IFTYPE_UNSPECIFIED;

	if (!info->attrs[NL80211_ATTR_IFNAME])
		return -EINVAL;

	if (info->attrs[NL80211_ATTR_IFTYPE]) {
		type = nla_get_u32(info->attrs[NL80211_ATTR_IFTYPE]);
		if (type > NL80211_IFTYPE_MAX)
			return -EINVAL;
	}

	drv = cfg80211_get_dev_from_info(info);
	if (IS_ERR(drv))
		return PTR_ERR(drv);

	if (!drv->ops->add_virtual_intf) {
		err = -EOPNOTSUPP;
		goto unlock;
	}

	rtnl_lock();
	err = drv->ops->add_virtual_intf(&drv->wiphy,
		nla_data(info->attrs[NL80211_ATTR_IFNAME]), type);
	rtnl_unlock();

 unlock:
	cfg80211_put_dev(drv);
	return err;
}

static int nl80211_del_interface(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *drv;
	int ifindex, err;
	struct net_device *dev;

	err = get_drv_dev_by_info_ifindex(info, &drv, &dev);
	if (err)
		return err;
	ifindex = dev->ifindex;
	dev_put(dev);

	if (!drv->ops->del_virtual_intf) {
		err = -EOPNOTSUPP;
		goto out;
	}

	rtnl_lock();
	err = drv->ops->del_virtual_intf(&drv->wiphy, ifindex);
	rtnl_unlock();

 out:
	cfg80211_put_dev(drv);
	return err;
}

static struct genl_ops nl80211_ops[] = {
	{
		.cmd = NL80211_CMD_GET_WIPHY,
		.doit = nl80211_get_wiphy,
		.dumpit = nl80211_dump_wiphy,
		.policy = nl80211_policy,
		/* can be retrieved by unprivileged users */
	},
	{
		.cmd = NL80211_CMD_SET_WIPHY,
		.doit = nl80211_set_wiphy,
		.policy = nl80211_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = NL80211_CMD_GET_INTERFACE,
		.doit = nl80211_get_interface,
		.dumpit = nl80211_dump_interface,
		.policy = nl80211_policy,
		/* can be retrieved by unprivileged users */
	},
	{
		.cmd = NL80211_CMD_SET_INTERFACE,
		.doit = nl80211_set_interface,
		.policy = nl80211_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = NL80211_CMD_NEW_INTERFACE,
		.doit = nl80211_new_interface,
		.policy = nl80211_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = NL80211_CMD_DEL_INTERFACE,
		.doit = nl80211_del_interface,
		.policy = nl80211_policy,
		.flags = GENL_ADMIN_PERM,
	},
};

/* multicast groups */
static struct genl_multicast_group nl80211_config_mcgrp = {
	.name = "config",
};

/* notification functions */

void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev)
{
	struct sk_buff *msg;

	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!msg)
		return;

	if (nl80211_send_wiphy(msg, 0, 0, 0, rdev) < 0) {
		nlmsg_free(msg);
		return;
	}

	genlmsg_multicast(msg, 0, nl80211_config_mcgrp.id, GFP_KERNEL);
}

/* initialisation/exit functions */

int nl80211_init(void)
{
	int err, i;

	err = genl_register_family(&nl80211_fam);
	if (err)
		return err;

	for (i = 0; i < ARRAY_SIZE(nl80211_ops); i++) {
		err = genl_register_ops(&nl80211_fam, &nl80211_ops[i]);
		if (err)
			goto err_out;
	}

	err = genl_register_mc_group(&nl80211_fam, &nl80211_config_mcgrp);
	if (err)
		goto err_out;

	return 0;
 err_out:
	genl_unregister_family(&nl80211_fam);
	return err;
}

void nl80211_exit(void)
{
	genl_unregister_family(&nl80211_fam);
}