wext: refactor

Refactor wext to
 * split out iwpriv handling
 * split out iwspy handling
 * split out procfs support
 * allow cfg80211 to have wireless extensions compat code
   w/o CONFIG_WIRELESS_EXT

After this, drivers need to
 - select WIRELESS_EXT	- for wext support
 - select WEXT_PRIV	- for iwpriv support
 - select WEXT_SPY	- for iwspy support

except cfg80211 -- which gets new hooks in wext-core.c
and can then get wext handlers without CONFIG_WIRELESS_EXT.

Wireless extensions procfs support is auto-selected
based on PROC_FS and anything that requires the wext core
(i.e. WIRELESS_EXT or CFG80211_WEXT).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 248 insertions, 0 deletions

diff --git a/net/wireless/wext-priv.c b/net/wireless/wext-priv.c
new file mode 100644
index 00000000000..a3c2277de9e
--- /dev/null
+++ b/net/wireless/wext-priv.c
@@ -0,0 +1,248 @@
+/*
+ * This file implement the Wireless Extensions priv API.
+ *
+ * Authors :	Jean Tourrilhes - HPL - <jt@hpl.hp.com>
+ * Copyright (c) 1997-2007 Jean Tourrilhes, All Rights Reserved.
+ * Copyright	2009 Johannes Berg <johannes@sipsolutions.net>
+ *
+ * (As all part of the Linux kernel, this file is GPL)
+ */
+#include <linux/wireless.h>
+#include <linux/netdevice.h>
+#include <net/iw_handler.h>
+#include <net/wext.h>
+
+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;
+}
+
+/* Size (in bytes) of the various private data types */
+static const char iw_priv_type_size[] = {
+	0,				/* IW_PRIV_TYPE_NONE */
+	1,				/* IW_PRIV_TYPE_BYTE */
+	1,				/* IW_PRIV_TYPE_CHAR */
+	0,				/* Not defined */
+	sizeof(__u32),			/* IW_PRIV_TYPE_INT */
+	sizeof(struct iw_freq),		/* IW_PRIV_TYPE_FLOAT */
+	sizeof(struct sockaddr),	/* IW_PRIV_TYPE_ADDR */
+	0,				/* Not defined */
+};
+
+static 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];
+}
+
+static int adjust_priv_size(__u16 args, struct iw_point *iwp)
+{
+	int	num = iwp->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];
+}
+
+/*
+ * 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 get_priv_descr_and_size(struct net_device *dev, unsigned int cmd,
+				   const struct iw_priv_args **descrp)
+{
+	const struct iw_priv_args *descr;
+	int i, extra_size;
+
+	descr = NULL;
+	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;
+		}
+	}
+
+	extra_size = 0;
+	if (descr) {
+		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;
+		}
+	}
+	*descrp = descr;
+	return extra_size;
+}
+
+static int ioctl_private_iw_point(struct iw_point *iwp, unsigned int cmd,
+				  const struct iw_priv_args *descr,
+				  iw_handler handler, struct net_device *dev,
+				  struct iw_request_info *info, int extra_size)
+{
+	char *extra;
+	int err;
+
+	/* Check what user space is giving us */
+	if (IW_IS_SET(cmd)) {
+		if (!iwp->pointer && iwp->length != 0)
+			return -EFAULT;
+
+		if (iwp->length > (descr->set_args & IW_PRIV_SIZE_MASK))
+			return -E2BIG;
+	} else if (!iwp->pointer)
+		return -EFAULT;
+
+	extra = kmalloc(extra_size, GFP_KERNEL);
+	if (!extra)
+		return -ENOMEM;
+
+	/* If it is a SET, get all the extra data in here */
+	if (IW_IS_SET(cmd) && (iwp->length != 0)) {
+		if (copy_from_user(extra, iwp->pointer, extra_size)) {
+			err = -EFAULT;
+			goto out;
+		}
+	}
+
+	/* Call the handler */
+	err = handler(dev, info, (union iwreq_data *) iwp, extra);
+
+	/* If we have something to return to the user */
+	if (!err && 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, iwp);
+
+		if (copy_to_user(iwp->pointer, extra, extra_size))
+			err =  -EFAULT;
+	}
+
+out:
+	kfree(extra);
+	return err;
+}
+
+int ioctl_private_call(struct net_device *dev, struct iwreq *iwr,
+		       unsigned int cmd, struct iw_request_info *info,
+		       iw_handler handler)
+{
+	int extra_size = 0, ret = -EINVAL;
+	const struct iw_priv_args *descr;
+
+	extra_size = get_priv_descr_and_size(dev, cmd, &descr);
+
+	/* 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 {
+		ret = ioctl_private_iw_point(&iwr->u.data, cmd, descr,
+					     handler, dev, info, extra_size);
+	}
+
+	/* Call commit handler if needed and defined */
+	if (ret == -EIWCOMMIT)
+		ret = call_commit_handler(dev);
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+int compat_private_call(struct net_device *dev, struct iwreq *iwr,
+			unsigned int cmd, struct iw_request_info *info,
+			iw_handler handler)
+{
+	const struct iw_priv_args *descr;
+	int ret, extra_size;
+
+	extra_size = get_priv_descr_and_size(dev, cmd, &descr);
+
+	/* 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 {
+		struct compat_iw_point *iwp_compat;
+		struct iw_point iwp;
+
+		iwp_compat = (struct compat_iw_point *) &iwr->u.data;
+		iwp.pointer = compat_ptr(iwp_compat->pointer);
+		iwp.length = iwp_compat->length;
+		iwp.flags = iwp_compat->flags;
+
+		ret = ioctl_private_iw_point(&iwp, cmd, descr,
+					     handler, dev, info, extra_size);
+
+		iwp_compat->pointer = ptr_to_compat(iwp.pointer);
+		iwp_compat->length = iwp.length;
+		iwp_compat->flags = iwp.flags;
+	}
+
+	/* Call commit handler if needed and defined */
+	if (ret == -EIWCOMMIT)
+		ret = call_commit_handler(dev);
+
+	return ret;
+}
+#endif