wext.c

linux 内核源代码

/*
 * Calculate size of private arguments
 */
static inline int get_priv_size(__u16	args)
{
	int	num = args & IW_PRIV_SIZE_MASK;
	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;

	return num * iw_priv_type_size[type];
}

/* ---------------------------------------------------------------- */
/*
 * Re-calculate the size of private arguments
 */
static inline int adjust_priv_size(__u16		args,
				   union iwreq_data *	wrqu)
{
	int	num = wrqu->data.length;
	int	max = args & IW_PRIV_SIZE_MASK;
	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;

	/* Make sure the driver doesn't goof up */
	if (max < num)
		num = max;

	return num * iw_priv_type_size[type];
}

/* ---------------------------------------------------------------- */
/*
 * Standard Wireless Handler : get wireless stats
 *	Allow programatic access to /proc/net/wireless even if /proc
 *	doesn't exist... Also more efficient...
 */
static int iw_handler_get_iwstats(struct net_device *		dev,
				  struct iw_request_info *	info,
				  union iwreq_data *		wrqu,
				  char *			extra)
{
	/* Get stats from the driver */
	struct iw_statistics *stats;

	stats = get_wireless_stats(dev);
	if (stats) {
		/* Copy statistics to extra */
		memcpy(extra, stats, sizeof(struct iw_statistics));
		wrqu->data.length = sizeof(struct iw_statistics);

		/* Check if we need to clear the updated flag */
		if (wrqu->data.flags != 0)
			stats->qual.updated &= ~IW_QUAL_ALL_UPDATED;
		return 0;
	} else
		return -EOPNOTSUPP;
}

/* ---------------------------------------------------------------- */
/*
 * Standard Wireless Handler : get iwpriv definitions
 * Export the driver private handler definition
 * They will be picked up by tools like iwpriv...
 */
static int iw_handler_get_private(struct net_device *		dev,
				  struct iw_request_info *	info,
				  union iwreq_data *		wrqu,
				  char *			extra)
{
	/* Check if the driver has something to export */
	if ((dev->wireless_handlers->num_private_args == 0) ||
	   (dev->wireless_handlers->private_args == NULL))
		return -EOPNOTSUPP;

	/* Check if there is enough buffer up there */
	if (wrqu->data.length < dev->wireless_handlers->num_private_args) {
		/* User space can't know in advance how large the buffer
		 * needs to be. Give it a hint, so that we can support
		 * any size buffer we want somewhat efficiently... */
		wrqu->data.length = dev->wireless_handlers->num_private_args;
		return -E2BIG;
	}

	/* Set the number of available ioctls. */
	wrqu->data.length = dev->wireless_handlers->num_private_args;

	/* Copy structure to the user buffer. */
	memcpy(extra, dev->wireless_handlers->private_args,
	       sizeof(struct iw_priv_args) * wrqu->data.length);

	return 0;
}


/******************** /proc/net/wireless SUPPORT ********************/
/*
 * The /proc/net/wireless file is a human readable user-space interface
 * exporting various wireless specific statistics from the wireless devices.
 * This is the most popular part of the Wireless Extensions ;-)
 *
 * This interface is a pure clone of /proc/net/dev (in net/core/dev.c).
 * The content of the file is basically the content of "struct iw_statistics".
 */

#ifdef CONFIG_PROC_FS

/* ---------------------------------------------------------------- */
/*
 * Print one entry (line) of /proc/net/wireless
 */
static void wireless_seq_printf_stats(struct seq_file *seq,
				      struct net_device *dev)
{
	/* Get stats from the driver */
	struct iw_statistics *stats = get_wireless_stats(dev);

	if (stats) {
		seq_printf(seq, "%6s: %04x  %3d%c  %3d%c  %3d%c  %6d %6d %6d "
				"%6d %6d   %6d\n",
			   dev->name, stats->status, stats->qual.qual,
			   stats->qual.updated & IW_QUAL_QUAL_UPDATED
			   ? '.' : ' ',
			   ((__s32) stats->qual.level) -
			   ((stats->qual.updated & IW_QUAL_DBM) ? 0x100 : 0),
			   stats->qual.updated & IW_QUAL_LEVEL_UPDATED
			   ? '.' : ' ',
			   ((__s32) stats->qual.noise) -
			   ((stats->qual.updated & IW_QUAL_DBM) ? 0x100 : 0),
			   stats->qual.updated & IW_QUAL_NOISE_UPDATED
			   ? '.' : ' ',
			   stats->discard.nwid, stats->discard.code,
			   stats->discard.fragment, stats->discard.retries,
			   stats->discard.misc, stats->miss.beacon);
		stats->qual.updated &= ~IW_QUAL_ALL_UPDATED;
	}
}

/* ---------------------------------------------------------------- */
/*
 * Print info for /proc/net/wireless (print all entries)
 */
static int wireless_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "Inter-| sta-|   Quality        |   Discarded "
				"packets               | Missed | WE\n"
				" face | tus | link level noise |  nwid  "
				"crypt   frag  retry   misc | beacon | %d\n",
			   WIRELESS_EXT);
	else
		wireless_seq_printf_stats(seq, v);
	return 0;
}

static const struct seq_operations wireless_seq_ops = {
	.start = dev_seq_start,
	.next  = dev_seq_next,
	.stop  = dev_seq_stop,
	.show  = wireless_seq_show,
};

static int wireless_seq_open(struct inode *inode, struct file *file)
{
	struct seq_file *seq;
	int res;
	res = seq_open(file, &wireless_seq_ops);
	if (!res) {
		seq = file->private_data;
		seq->private = get_proc_net(inode);
		if (!seq->private) {
			seq_release(inode, file);
			res = -ENXIO;
		}
	}
	return res;
}

static int wireless_seq_release(struct inode *inode, struct file *file)
{
	struct seq_file *seq = file->private_data;
	struct net *net = seq->private;
	put_net(net);
	return seq_release(inode, file);
}

static const struct file_operations wireless_seq_fops = {
	.owner	 = THIS_MODULE,
	.open    = wireless_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = wireless_seq_release,
};

int wext_proc_init(struct net *net)
{
	/* Create /proc/net/wireless entry */
	if (!proc_net_fops_create(net, "wireless", S_IRUGO, &wireless_seq_fops))
		return -ENOMEM;

	return 0;
}

void wext_proc_exit(struct net *net)
{
	proc_net_remove(net, "wireless");
}
#endif	/* CONFIG_PROC_FS */

/************************** IOCTL SUPPORT **************************/
/*
 * The original user space API to configure all those Wireless Extensions
 * is through IOCTLs.
 * In there, we check if we need to call the new driver API (iw_handler)
 * or just call the driver ioctl handler.
 */

/* ---------------------------------------------------------------- */
/*
 * Wrapper to call a standard Wireless Extension handler.
 * We do various checks and also take care of moving data between
 * user space and kernel space.
 */
static int ioctl_standard_call(struct net_device *	dev,
			       struct ifreq *		ifr,
			       unsigned int		cmd,
			       iw_handler		handler)
{
	struct iwreq *				iwr = (struct iwreq *) ifr;
	const struct iw_ioctl_description *	descr;
	struct iw_request_info			info;
	int					ret = -EINVAL;

	/* Get the description of the IOCTL */
	if ((cmd - SIOCIWFIRST) >= standard_ioctl_num)
		return -EOPNOTSUPP;
	descr = &(standard_ioctl[cmd - SIOCIWFIRST]);

	/* Prepare the call */
	info.cmd = cmd;
	info.flags = 0;

	/* Check if we have a pointer to user space data or not */
	if (descr->header_type != IW_HEADER_TYPE_POINT) {

		/* No extra arguments. Trivial to handle */
		ret = handler(dev, &info, &(iwr->u), NULL);

		/* Generate an event to notify listeners of the change */
		if ((descr->flags & IW_DESCR_FLAG_EVENT) &&
		   ((ret == 0) || (ret == -EIWCOMMIT)))
			wireless_send_event(dev, cmd, &(iwr->u), NULL);
	} else {
		char *	extra;
		int	extra_size;
		int	user_length = 0;
		int	err;
		int	essid_compat = 0;

		/* Calculate space needed by arguments. Always allocate
		 * for max space. Easier, and won't last long... */
		extra_size = descr->max_tokens * descr->token_size;

		/* Check need for ESSID compatibility for WE < 21 */
		switch (cmd) {
		case SIOCSIWESSID:
		case SIOCGIWESSID:
		case SIOCSIWNICKN:
		case SIOCGIWNICKN:
			if (iwr->u.data.length == descr->max_tokens + 1)
				essid_compat = 1;
			else if (IW_IS_SET(cmd) && (iwr->u.data.length != 0)) {
				char essid[IW_ESSID_MAX_SIZE + 1];

				err = copy_from_user(essid, iwr->u.data.pointer,
						     iwr->u.data.length *
						     descr->token_size);
				if (err)
					return -EFAULT;

				if (essid[iwr->u.data.length - 1] == '\0')
					essid_compat = 1;
			}
			break;
		default:
			break;
		}

		iwr->u.data.length -= essid_compat;

		/* Check what user space is giving us */
		if (IW_IS_SET(cmd)) {
			/* Check NULL pointer */
			if ((iwr->u.data.pointer == NULL) &&
			   (iwr->u.data.length != 0))
				return -EFAULT;
			/* Check if number of token fits within bounds */
			if (iwr->u.data.length > descr->max_tokens)
				return -E2BIG;
			if (iwr->u.data.length < descr->min_tokens)
				return -EINVAL;
		} else {
			/* Check NULL pointer */
			if (iwr->u.data.pointer == NULL)
				return -EFAULT;
			/* Save user space buffer size for checking */
			user_length = iwr->u.data.length;

			/* Don't check if user_length > max to allow forward
			 * compatibility. The test user_length < min is
			 * implied by the test at the end. */

			/* Support for very large requests */
			if ((descr->flags & IW_DESCR_FLAG_NOMAX) &&
			   (user_length > descr->max_tokens)) {
				/* Allow userspace to GET more than max so
				 * we can support any size GET requests.
				 * There is still a limit : -ENOMEM. */
				extra_size = user_length * descr->token_size;
				/* Note : user_length is originally a __u16,
				 * and token_size is controlled by us,
				 * so extra_size won't get negative and
				 * won't overflow... */
			}
		}

		/* Create the kernel buffer */
		/*    kzalloc ensures NULL-termination for essid_compat */
		extra = kzalloc(extra_size, GFP_KERNEL);
		if (extra == NULL)
			return -ENOMEM;

		/* If it is a SET, get all the extra data in here */
		if (IW_IS_SET(cmd) && (iwr->u.data.length != 0)) {
			err = copy_from_user(extra, iwr->u.data.pointer,
					     iwr->u.data.length *
					     descr->token_size);
			if (err) {
				kfree(extra);
				return -EFAULT;
			}
		}

		/* Call the handler */
		ret = handler(dev, &info, &(iwr->u), extra);

		iwr->u.data.length += essid_compat;

		/* If we have something to return to the user */
		if (!ret && IW_IS_GET(cmd)) {
			/* Check if there is enough buffer up there */
			if (user_length < iwr->u.data.length) {
				kfree(extra);
				return -E2BIG;
			}

			err = copy_to_user(iwr->u.data.pointer, extra,
					   iwr->u.data.length *
					   descr->token_size);
			if (err)
				ret =  -EFAULT;
		}

		/* Generate an event to notify listeners of the change */
		if ((descr->flags & IW_DESCR_FLAG_EVENT) &&
		   ((ret == 0) || (ret == -EIWCOMMIT))) {
			if (descr->flags & IW_DESCR_FLAG_RESTRICT)
				/* If the event is restricted, don't
				 * export the payload */
				wireless_send_event(dev, cmd, &(iwr->u), NULL);
			else
				wireless_send_event(dev, cmd, &(iwr->u),
						    extra);
		}

		/* Cleanup - I told you it wasn't that long ;-) */
		kfree(extra);
	}

	/* Call commit handler if needed and defined */
	if (ret == -EIWCOMMIT)
		ret = call_commit_handler(dev);

	/* Here, we will generate the appropriate event if needed */

	return ret;
}

/* ---------------------------------------------------------------- */
/*
 * Wrapper to call a private Wireless Extension handler.
 * We do various checks and also take care of moving data between
 * user space and kernel space.
 * It's not as nice and slimline as the standard wrapper. The cause
 * is struct iw_priv_args, which was not really designed for the
 * job we are going here.
 *
 * IMPORTANT : This function prevent to set and get data on the same
 * IOCTL and enforce the SET/GET convention. Not doing it would be
 * far too hairy...
 * If you need to set and get data at the same time, please don't use
 * a iw_handler but process it in your ioctl handler (i.e. use the
 * old driver API).
 */
static int ioctl_private_call(struct net_device *dev, struct ifreq *ifr,
			      unsigned int cmd, iw_handler handler)
{
	struct iwreq *			iwr = (struct iwreq *) ifr;
	const struct iw_priv_args *	descr = NULL;
	struct iw_request_info		info;
	int				extra_size = 0;
	int				i;
	int				ret = -EINVAL;

	/* Get the description of the IOCTL */
	for (i = 0; i < dev->wireless_handlers->num_private_args; i++)
		if (cmd == dev->wireless_handlers->private_args[i].cmd) {
			descr = &(dev->wireless_handlers->private_args[i]);
			break;
		}

	/* Compute the size of the set/get arguments */
	if (descr != NULL) {
		if (IW_IS_SET(cmd)) {
			int	offset = 0;	/* For sub-ioctls */
			/* Check for sub-ioctl handler */
			if (descr->name[0] == '\0')
				/* Reserve one int for sub-ioctl index */
				offset = sizeof(__u32);

			/* Size of set arguments */
			extra_size = get_priv_size(descr->set_args);

			/* Does it fits in iwr ? */
			if ((descr->set_args & IW_PRIV_SIZE_FIXED) &&
			   ((extra_size + offset) <= IFNAMSIZ))
				extra_size = 0;
		} else {
			/* Size of get arguments */
			extra_size = get_priv_size(descr->get_args);

			/* Does it fits in iwr ? */
			if ((descr->get_args & IW_PRIV_SIZE_FIXED) &&
			   (extra_size <= IFNAMSIZ))
				extra_size = 0;
		}
	}

	/* Prepare the call */
	info.cmd = cmd;
	info.flags = 0;

	/* Check if we have a pointer to user space data or not. */
	if (extra_size == 0) {
		/* No extra arguments. Trivial to handle */
		ret = handler(dev, &info, &(iwr->u), (char *) &(iwr->u));
	} else {
		char *	extra;
		int	err;

		/* Check what user space is giving us */
		if (IW_IS_SET(cmd)) {
			/* Check NULL pointer */
			if ((iwr->u.data.pointer == NULL) &&
			   (iwr->u.data.length != 0))
				return -EFAULT;

			/* Does it fits within bounds ? */
			if (iwr->u.data.length > (descr->set_args &
						 IW_PRIV_SIZE_MASK))
				return -E2BIG;
		} else if (iwr->u.data.pointer == NULL)
			return -EFAULT;

		/* Always allocate for max space. Easier, and won't last
		 * long... */
		extra = kmalloc(extra_size, GFP_KERNEL);
		if (extra == NULL)
			return -ENOMEM;

		/* If it is a SET, get all the extra data in here */
		if (IW_IS_SET(cmd) && (iwr->u.data.length != 0)) {
			err = copy_from_user(extra, iwr->u.data.pointer,
					     extra_size);
			if (err) {
				kfree(extra);
				return -EFAULT;
			}
		}

		/* Call the handler */
		ret = handler(dev, &info, &(iwr->u), extra);

		/* If we have something to return to the user */
		if (!ret && IW_IS_GET(cmd)) {

			/* Adjust for the actual length if it's variable,
			 * avoid leaking kernel bits outside. */
			if (!(descr->get_args & IW_PRIV_SIZE_FIXED)) {
				extra_size = adjust_priv_size(descr->get_args,
							      &(iwr->u));
			}

			err = copy_to_user(iwr->u.data.pointer, extra,
					   extra_size);
			if (err)
				ret =  -EFAULT;
		}

		/* Cleanup - I told you it wasn't that long ;-) */
		kfree(extra);
	}


	/* Call commit handler if needed and defined */