wext.c

linux 内核源代码

	if (ret == -EIWCOMMIT)
		ret = call_commit_handler(dev);

	return ret;
}

/* ---------------------------------------------------------------- */
/*
 * Main IOCTl dispatcher.
 * Check the type of IOCTL and call the appropriate wrapper...
 */
static int wireless_process_ioctl(struct net *net, struct ifreq *ifr, unsigned int cmd)
{
	struct net_device *dev;
	iw_handler	handler;

	/* Permissions are already checked in dev_ioctl() before calling us.
	 * The copy_to/from_user() of ifr is also dealt with in there */

	/* Make sure the device exist */
	if ((dev = __dev_get_by_name(net, ifr->ifr_name)) == NULL)
		return -ENODEV;

	/* A bunch of special cases, then the generic case...
	 * Note that 'cmd' is already filtered in dev_ioctl() with
	 * (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) */
	if (cmd == SIOCGIWSTATS)
		return ioctl_standard_call(dev, ifr, cmd,
					   &iw_handler_get_iwstats);

	if (cmd == SIOCGIWPRIV && dev->wireless_handlers)
		return ioctl_standard_call(dev, ifr, cmd,
					   &iw_handler_get_private);

	/* Basic check */
	if (!netif_device_present(dev))
		return -ENODEV;

	/* New driver API : try to find the handler */
	handler = get_handler(dev, cmd);
	if (handler) {
		/* Standard and private are not the same */
		if (cmd < SIOCIWFIRSTPRIV)
			return ioctl_standard_call(dev, ifr, cmd, handler);
		else
			return ioctl_private_call(dev, ifr, cmd, handler);
	}
	/* Old driver API : call driver ioctl handler */
	if (dev->do_ioctl)
		return dev->do_ioctl(dev, ifr, cmd);
	return -EOPNOTSUPP;
}

/* entry point from dev ioctl */
int wext_handle_ioctl(struct net *net, struct ifreq *ifr, unsigned int cmd,
		      void __user *arg)
{
	int ret;

	/* If command is `set a parameter', or
	 * `get the encoding parameters', check if
	 * the user has the right to do it */
	if ((IW_IS_SET(cmd) || cmd == SIOCGIWENCODE || cmd == SIOCGIWENCODEEXT)
	    && !capable(CAP_NET_ADMIN))
		return -EPERM;

	dev_load(net, ifr->ifr_name);
	rtnl_lock();
	ret = wireless_process_ioctl(net, ifr, cmd);
	rtnl_unlock();
	if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct iwreq)))
		return -EFAULT;
	return ret;
}

/************************* EVENT PROCESSING *************************/
/*
 * Process events generated by the wireless layer or the driver.
 * Most often, the event will be propagated through rtnetlink
 */

/* ---------------------------------------------------------------- */
/*
 * Locking...
 * ----------
 *
 * Thanks to Herbert Xu <[e-mail]> for fixing
 * the locking issue in here and implementing this code !
 *
 * The issue : wireless_send_event() is often called in interrupt context,
 * while the Netlink layer can never be called in interrupt context.
 * The fully formed RtNetlink events are queued, and then a tasklet is run
 * to feed those to Netlink.
 * The skb_queue is interrupt safe, and its lock is not held while calling
 * Netlink, so there is no possibility of dealock.
 * Jean II
 */

static struct sk_buff_head wireless_nlevent_queue;

static int __init wireless_nlevent_init(void)
{
	skb_queue_head_init(&wireless_nlevent_queue);
	return 0;
}

subsys_initcall(wireless_nlevent_init);

static void wireless_nlevent_process(unsigned long data)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&wireless_nlevent_queue)))
		rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
}

static DECLARE_TASKLET(wireless_nlevent_tasklet, wireless_nlevent_process, 0);

/* ---------------------------------------------------------------- */
/*
 * Fill a rtnetlink message with our event data.
 * Note that we propage only the specified event and don't dump the
 * current wireless config. Dumping the wireless config is far too
 * expensive (for each parameter, the driver need to query the hardware).
 */
static int rtnetlink_fill_iwinfo(struct sk_buff *skb, struct net_device *dev,
				 int type, char *event, int event_len)
{
	struct ifinfomsg *r;
	struct nlmsghdr  *nlh;

	nlh = nlmsg_put(skb, 0, 0, type, sizeof(*r), 0);
	if (nlh == NULL)
		return -EMSGSIZE;

	r = nlmsg_data(nlh);
	r->ifi_family = AF_UNSPEC;
	r->__ifi_pad = 0;
	r->ifi_type = dev->type;
	r->ifi_index = dev->ifindex;
	r->ifi_flags = dev_get_flags(dev);
	r->ifi_change = 0;	/* Wireless changes don't affect those flags */

	/* Add the wireless events in the netlink packet */
	NLA_PUT(skb, IFLA_WIRELESS, event_len, event);

	return nlmsg_end(skb, nlh);

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

/* ---------------------------------------------------------------- */
/*
 * Create and broadcast and send it on the standard rtnetlink socket
 * This is a pure clone rtmsg_ifinfo() in net/core/rtnetlink.c
 * Andrzej Krzysztofowicz mandated that I used a IFLA_XXX field
 * within a RTM_NEWLINK event.
 */
static void rtmsg_iwinfo(struct net_device *dev, char *event, int event_len)
{
	struct sk_buff *skb;
	int err;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!skb)
		return;

	err = rtnetlink_fill_iwinfo(skb, dev, RTM_NEWLINK, event, event_len);
	if (err < 0) {
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		return;
	}

	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
	skb_queue_tail(&wireless_nlevent_queue, skb);
	tasklet_schedule(&wireless_nlevent_tasklet);
}

/* ---------------------------------------------------------------- */
/*
 * Main event dispatcher. Called from other parts and drivers.
 * Send the event on the appropriate channels.
 * May be called from interrupt context.
 */
void wireless_send_event(struct net_device *	dev,
			 unsigned int		cmd,
			 union iwreq_data *	wrqu,
			 char *			extra)
{
	const struct iw_ioctl_description *	descr = NULL;
	int extra_len = 0;
	struct iw_event  *event;		/* Mallocated whole event */
	int event_len;				/* Its size */
	int hdr_len;				/* Size of the event header */
	int wrqu_off = 0;			/* Offset in wrqu */
	/* Don't "optimise" the following variable, it will crash */
	unsigned	cmd_index;		/* *MUST* be unsigned */

	/* Get the description of the Event */
	if (cmd <= SIOCIWLAST) {
		cmd_index = cmd - SIOCIWFIRST;
		if (cmd_index < standard_ioctl_num)
			descr = &(standard_ioctl[cmd_index]);
	} else {
		cmd_index = cmd - IWEVFIRST;
		if (cmd_index < standard_event_num)
			descr = &(standard_event[cmd_index]);
	}
	/* Don't accept unknown events */
	if (descr == NULL) {
		/* Note : we don't return an error to the driver, because
		 * the driver would not know what to do about it. It can't
		 * return an error to the user, because the event is not
		 * initiated by a user request.
		 * The best the driver could do is to log an error message.
		 * We will do it ourselves instead...
		 */
		printk(KERN_ERR "%s (WE) : Invalid/Unknown Wireless Event (0x%04X)\n",
		       dev->name, cmd);
		return;
	}

	/* Check extra parameters and set extra_len */
	if (descr->header_type == IW_HEADER_TYPE_POINT) {
		/* Check if number of token fits within bounds */
		if (wrqu->data.length > descr->max_tokens) {
			printk(KERN_ERR "%s (WE) : Wireless Event too big (%d)\n", dev->name, wrqu->data.length);
			return;
		}
		if (wrqu->data.length < descr->min_tokens) {
			printk(KERN_ERR "%s (WE) : Wireless Event too small (%d)\n", dev->name, wrqu->data.length);
			return;
		}
		/* Calculate extra_len - extra is NULL for restricted events */
		if (extra != NULL)
			extra_len = wrqu->data.length * descr->token_size;
		/* Always at an offset in wrqu */
		wrqu_off = IW_EV_POINT_OFF;
	}

	/* Total length of the event */
	hdr_len = event_type_size[descr->header_type];
	event_len = hdr_len + extra_len;

	/* Create temporary buffer to hold the event */
	event = kmalloc(event_len, GFP_ATOMIC);
	if (event == NULL)
		return;

	/* Fill event */
	event->len = event_len;
	event->cmd = cmd;
	memcpy(&event->u, ((char *) wrqu) + wrqu_off, hdr_len - IW_EV_LCP_LEN);
	if (extra)
		memcpy(((char *) event) + hdr_len, extra, extra_len);

	/* Send via the RtNetlink event channel */
	rtmsg_iwinfo(dev, (char *) event, event_len);

	/* Cleanup */
	kfree(event);

	return;		/* Always success, I guess ;-) */
}
EXPORT_SYMBOL(wireless_send_event);

/********************** ENHANCED IWSPY SUPPORT **********************/
/*
 * In the old days, the driver was handling spy support all by itself.
 * Now, the driver can delegate this task to Wireless Extensions.
 * It needs to use those standard spy iw_handler in struct iw_handler_def,
 * push data to us via wireless_spy_update() and include struct iw_spy_data
 * in its private part (and export it in net_device->wireless_data->spy_data).
 * One of the main advantage of centralising spy support here is that
 * it becomes much easier to improve and extend it without having to touch
 * the drivers. One example is the addition of the Spy-Threshold events.
 */

/* ---------------------------------------------------------------- */
/*
 * Return the pointer to the spy data in the driver.
 * Because this is called on the Rx path via wireless_spy_update(),
 * we want it to be efficient...
 */
static inline struct iw_spy_data *get_spydata(struct net_device *dev)
{
	/* This is the new way */
	if (dev->wireless_data)
		return dev->wireless_data->spy_data;
	return NULL;
}

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : set Spy List
 */
int iw_handler_set_spy(struct net_device *	dev,
		       struct iw_request_info *	info,
		       union iwreq_data *	wrqu,
		       char *			extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct sockaddr *	address = (struct sockaddr *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Disable spy collection while we copy the addresses.
	 * While we copy addresses, any call to wireless_spy_update()
	 * will NOP. This is OK, as anyway the addresses are changing. */
	spydata->spy_number = 0;

	/* We want to operate without locking, because wireless_spy_update()
	 * most likely will happen in the interrupt handler, and therefore
	 * have its own locking constraints and needs performance.
	 * The rtnl_lock() make sure we don't race with the other iw_handlers.
	 * This make sure wireless_spy_update() "see" that the spy list
	 * is temporarily disabled. */
	smp_wmb();

	/* Are there are addresses to copy? */
	if (wrqu->data.length > 0) {
		int i;

		/* Copy addresses */
		for (i = 0; i < wrqu->data.length; i++)
			memcpy(spydata->spy_address[i], address[i].sa_data,
			       ETH_ALEN);
		/* Reset stats */
		memset(spydata->spy_stat, 0,
		       sizeof(struct iw_quality) * IW_MAX_SPY);
	}

	/* Make sure above is updated before re-enabling */
	smp_wmb();

	/* Enable addresses */
	spydata->spy_number = wrqu->data.length;

	return 0;
}
EXPORT_SYMBOL(iw_handler_set_spy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : get Spy List
 */
int iw_handler_get_spy(struct net_device *	dev,
		       struct iw_request_info *	info,
		       union iwreq_data *	wrqu,
		       char *			extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct sockaddr *	address = (struct sockaddr *) extra;
	int			i;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	wrqu->data.length = spydata->spy_number;

	/* Copy addresses. */
	for (i = 0; i < spydata->spy_number; i++) 	{
		memcpy(address[i].sa_data, spydata->spy_address[i], ETH_ALEN);
		address[i].sa_family = AF_UNIX;
	}
	/* Copy stats to the user buffer (just after). */
	if (spydata->spy_number > 0)
		memcpy(extra  + (sizeof(struct sockaddr) *spydata->spy_number),
		       spydata->spy_stat,
		       sizeof(struct iw_quality) * spydata->spy_number);
	/* Reset updated flags. */
	for (i = 0; i < spydata->spy_number; i++)
		spydata->spy_stat[i].updated &= ~IW_QUAL_ALL_UPDATED;
	return 0;
}
EXPORT_SYMBOL(iw_handler_get_spy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : set spy threshold
 */
int iw_handler_set_thrspy(struct net_device *	dev,
			  struct iw_request_info *info,
			  union iwreq_data *	wrqu,
			  char *		extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct iw_thrspy *	threshold = (struct iw_thrspy *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Just do it */
	memcpy(&(spydata->spy_thr_low), &(threshold->low),
	       2 * sizeof(struct iw_quality));

	/* Clear flag */
	memset(spydata->spy_thr_under, '\0', sizeof(spydata->spy_thr_under));

	return 0;
}
EXPORT_SYMBOL(iw_handler_set_thrspy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : get spy threshold
 */
int iw_handler_get_thrspy(struct net_device *	dev,
			  struct iw_request_info *info,
			  union iwreq_data *	wrqu,
			  char *		extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct iw_thrspy *	threshold = (struct iw_thrspy *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Just do it */
	memcpy(&(threshold->low), &(spydata->spy_thr_low),
	       2 * sizeof(struct iw_quality));

	return 0;
}
EXPORT_SYMBOL(iw_handler_get_thrspy);

/*------------------------------------------------------------------*/
/*
 * Prepare and send a Spy Threshold event
 */
static void iw_send_thrspy_event(struct net_device *	dev,
				 struct iw_spy_data *	spydata,
				 unsigned char *	address,
				 struct iw_quality *	wstats)
{
	union iwreq_data	wrqu;
	struct iw_thrspy	threshold;

	/* Init */
	wrqu.data.length = 1;
	wrqu.data.flags = 0;
	/* Copy address */
	memcpy(threshold.addr.sa_data, address, ETH_ALEN);
	threshold.addr.sa_family = ARPHRD_ETHER;
	/* Copy stats */
	memcpy(&(threshold.qual), wstats, sizeof(struct iw_quality));
	/* Copy also thresholds */
	memcpy(&(threshold.low), &(spydata->spy_thr_low),
	       2 * sizeof(struct iw_quality));

	/* Send event to user space */
	wireless_send_event(dev, SIOCGIWTHRSPY, &wrqu, (char *) &threshold);
}

/* ---------------------------------------------------------------- */
/*
 * Call for the driver to update the spy data.
 * For now, the spy data is a simple array. As the size of the array is
 * small, this is good enough. If we wanted to support larger number of
 * spy addresses, we should use something more efficient...
 */
void wireless_spy_update(struct net_device *	dev,
			 unsigned char *	address,
			 struct iw_quality *	wstats)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	int			i;
	int			match = -1;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return;

	/* Update all records that match */
	for (i = 0; i < spydata->spy_number; i++)
		if (!compare_ether_addr(address, spydata->spy_address[i])) {
			memcpy(&(spydata->spy_stat[i]), wstats,
			       sizeof(struct iw_quality));
			match = i;
		}

	/* Generate an event if we cross the spy threshold.
	 * To avoid event storms, we have a simple hysteresis : we generate
	 * event only when we go under the low threshold or above the
	 * high threshold. */
	if (match >= 0) {
		if (spydata->spy_thr_under[match]) {
			if (wstats->level > spydata->spy_thr_high.level) {
				spydata->spy_thr_under[match] = 0;
				iw_send_thrspy_event(dev, spydata,
						     address, wstats);
			}
		} else {
			if (wstats->level < spydata->spy_thr_low.level) {
				spydata->spy_thr_under[match] = 1;
				iw_send_thrspy_event(dev, spydata,
						     address, wstats);
			}
		}
	}
}
EXPORT_SYMBOL(wireless_spy_update);