1 files changed, 421 insertions, 0 deletions
diff --git a/net/wimax/op-msg.c b/net/wimax/op-msg.c
new file mode 100644
index 0000000..cb3b4ad
--- /dev/null
+++ b/net/wimax/op-msg.c
@@ -0,0 +1,421 @@
+/*
+ * Linux WiMAX
+ * Generic messaging interface between userspace and driver/device
+ *
+ *
+ * Copyright (C) 2007-2008 Intel Corporation <linux-wimax@intel.com>
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * This implements a direct communication channel between user space and
+ * the driver/device, by which free form messages can be sent back and
+ * forth.
+ *
+ * This is intended for device-specific features, vendor quirks, etc.
+ *
+ * See include/net/wimax.h
+ *
+ * GENERIC NETLINK ENCODING AND CAPACITY
+ *
+ * A destination "pipe name" is added to each message; it is up to the
+ * drivers to assign or use those names (if using them at all).
+ *
+ * Messages are encoded as a binary netlink attribute using nla_put()
+ * using type NLA_UNSPEC (as some versions of libnl still in
+ * deployment don't yet understand NLA_BINARY).
+ *
+ * The maximum capacity of this transport is PAGESIZE per message (so
+ * the actual payload will be bit smaller depending on the
+ * netlink/generic netlink attributes and headers).
+ *
+ * RECEPTION OF MESSAGES
+ *
+ * When a message is received from user space, it is passed verbatim
+ * to the driver calling wimax_dev->op_msg_from_user(). The return
+ * value from this function is passed back to user space as an ack
+ * over the generic netlink protocol.
+ *
+ * The stack doesn't do any processing or interpretation of these
+ * messages.
+ *
+ * SENDING MESSAGES
+ *
+ * Messages can be sent with wimax_msg().
+ *
+ * If the message delivery needs to happen on a different context to
+ * that of its creation, wimax_msg_alloc() can be used to get a
+ * pointer to the message that can be delivered later on with
+ * wimax_msg_send().
+ *
+ * ROADMAP
+ *
+ * wimax_gnl_doit_msg_from_user()    Process a message from user space
+ *   wimax_dev_get_by_genl_info()
+ *   wimax_dev->op_msg_from_user()   Delivery of message to the driver
+ *
+ * wimax_msg()                       Send a message to user space
+ *   wimax_msg_alloc()
+ *   wimax_msg_send()
+ */
+#include <linux/device.h>
+#include <net/genetlink.h>
+#include <linux/netdevice.h>
+#include <linux/wimax.h>
+#include <linux/security.h>
+#include "wimax-internal.h"
+
+
+#define D_SUBMODULE op_msg
+#include "debug-levels.h"
+
+
+/**
+ * wimax_msg_alloc - Create a new skb for sending a message to userspace
+ *
+ * @wimax_dev: WiMAX device descriptor
+ * @pipe_name: "named pipe" the message will be sent to
+ * @msg: pointer to the message data to send
+ * @size: size of the message to send (in bytes), including the header.
+ * @gfp_flags: flags for memory allocation.
+ *
+ * Returns: %0 if ok, negative errno code on error
+ *
+ * Description:
+ *
+ * Allocates an skb that will contain the message to send to user
+ * space over the messaging pipe and initializes it, copying the
+ * payload.
+ *
+ * Once this call is done, you can deliver it with
+ * wimax_msg_send().
+ *
+ * IMPORTANT:
+ *
+ * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as
+ * wimax_msg_send() depends on skb->data being placed at the
+ * beginning of the user message.
+ */
+struct sk_buff *wimax_msg_alloc(struct wimax_dev *wimax_dev,
+				const char *pipe_name,
+				const void *msg, size_t size,
+				gfp_t gfp_flags)
+{
+	int result;
+	struct device *dev = wimax_dev->net_dev->dev.parent;
+	size_t msg_size;
+	void *genl_msg;
+	struct sk_buff *skb;
+
+	msg_size = nla_total_size(size)
+		+ nla_total_size(sizeof(u32))
+		+ (pipe_name ? nla_total_size(strlen(pipe_name)) : 0);
+	result = -ENOMEM;
+	skb = genlmsg_new(msg_size, gfp_flags);
+	if (skb == NULL)
+		goto error_new;
+	genl_msg = genlmsg_put(skb, 0, 0, &wimax_gnl_family,
+			       0, WIMAX_GNL_OP_MSG_TO_USER);
+	if (genl_msg == NULL) {
+		dev_err(dev, "no memory to create generic netlink message\n");
+		goto error_genlmsg_put;
+	}
+	result = nla_put_u32(skb, WIMAX_GNL_MSG_IFIDX,
+			     wimax_dev->net_dev->ifindex);
+	if (result < 0) {
+		dev_err(dev, "no memory to add ifindex attribute\n");
+		goto error_nla_put;
+	}
+	if (pipe_name) {
+		result = nla_put_string(skb, WIMAX_GNL_MSG_PIPE_NAME,
+					pipe_name);
+		if (result < 0) {
+			dev_err(dev, "no memory to add pipe_name attribute\n");
+			goto error_nla_put;
+		}
+	}
+	result = nla_put(skb, WIMAX_GNL_MSG_DATA, size, msg);
+	if (result < 0) {
+		dev_err(dev, "no memory to add payload in attribute\n");
+		goto error_nla_put;
+	}
+	genlmsg_end(skb, genl_msg);
+	return skb;
+
+error_nla_put:
+error_genlmsg_put:
+error_new:
+	nlmsg_free(skb);
+	return ERR_PTR(result);
+
+}
+EXPORT_SYMBOL_GPL(wimax_msg_alloc);
+
+
+/**
+ * wimax_msg_data_len - Return a pointer and size of a message's payload
+ *
+ * @msg: Pointer to a message created with wimax_msg_alloc()
+ * @size: Pointer to where to store the message's size
+ *
+ * Returns the pointer to the message data.
+ */
+const void *wimax_msg_data_len(struct sk_buff *msg, size_t *size)
+{
+	struct nlmsghdr *nlh = (void *) msg->head;
+	struct nlattr *nla;
+
+	nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
+			      WIMAX_GNL_MSG_DATA);
+	if (nla == NULL) {
+		printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
+		return NULL;
+	}
+	*size = nla_len(nla);
+	return nla_data(nla);
+}
+EXPORT_SYMBOL_GPL(wimax_msg_data_len);
+
+
+/**
+ * wimax_msg_data - Return a pointer to a message's payload
+ *
+ * @msg: Pointer to a message created with wimax_msg_alloc()
+ */
+const void *wimax_msg_data(struct sk_buff *msg)
+{
+	struct nlmsghdr *nlh = (void *) msg->head;
+	struct nlattr *nla;
+
+	nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
+			      WIMAX_GNL_MSG_DATA);
+	if (nla == NULL) {
+		printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
+		return NULL;
+	}
+	return nla_data(nla);
+}
+EXPORT_SYMBOL_GPL(wimax_msg_data);
+
+
+/**
+ * wimax_msg_len - Return a message's payload length
+ *
+ * @msg: Pointer to a message created with wimax_msg_alloc()
+ */
+ssize_t wimax_msg_len(struct sk_buff *msg)
+{
+	struct nlmsghdr *nlh = (void *) msg->head;
+	struct nlattr *nla;
+
+	nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr),
+			      WIMAX_GNL_MSG_DATA);
+	if (nla == NULL) {
+		printk(KERN_ERR "Cannot find attribute WIMAX_GNL_MSG_DATA\n");
+		return -EINVAL;
+	}
+	return nla_len(nla);
+}
+EXPORT_SYMBOL_GPL(wimax_msg_len);
+
+
+/**
+ * wimax_msg_send - Send a pre-allocated message to user space
+ *
+ * @wimax_dev: WiMAX device descriptor
+ *
+ * @skb: &struct sk_buff returned by wimax_msg_alloc(). Note the
+ *     ownership of @skb is transferred to this function.
+ *
+ * Returns: 0 if ok, < 0 errno code on error
+ *
+ * Description:
+ *
+ * Sends a free-form message that was preallocated with
+ * wimax_msg_alloc() and filled up.
+ *
+ * Assumes that once you pass an skb to this function for sending, it
+ * owns it and will release it when done (on success).
+ *
+ * IMPORTANT:
+ *
+ * Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as
+ * wimax_msg_send() depends on skb->data being placed at the
+ * beginning of the user message.
+ */
+int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb)
+{
+	int result;
+	struct device *dev = wimax_dev->net_dev->dev.parent;
+	void *msg = skb->data;
+	size_t size = skb->len;
+	might_sleep();
+
+	d_printf(1, dev, "CTX: wimax msg, %zu bytes\n", size);
+	d_dump(2, dev, msg, size);
+	result = genlmsg_multicast(skb, 0, wimax_gnl_mcg.id, GFP_KERNEL);
+	d_printf(1, dev, "CTX: genl multicast result %d\n", result);
+	if (result == -ESRCH)	/* Nobody connected, ignore it */
+		result = 0;	/* btw, the skb is freed already */
+	return result;
+}
+EXPORT_SYMBOL_GPL(wimax_msg_send);
+
+
+/**
+ * wimax_msg - Send a message to user space
+ *
+ * @wimax_dev: WiMAX device descriptor (properly referenced)
+ * @pipe_name: "named pipe" the message will be sent to
+ * @buf: pointer to the message to send.
+ * @size: size of the buffer pointed to by @buf (in bytes).
+ * @gfp_flags: flags for memory allocation.
+ *
+ * Returns: %0 if ok, negative errno code on error.
+ *
+ * Description:
+ *
+ * Sends a free-form message to user space on the device @wimax_dev.
+ *
+ * NOTES:
+ *
+ * Once the @skb is given to this function, who will own it and will
+ * release it when done (unless it returns error).
+ */
+int wimax_msg(struct wimax_dev *wimax_dev, const char *pipe_name,
+	      const void *buf, size_t size, gfp_t gfp_flags)
+{
+	int result = -ENOMEM;
+	struct sk_buff *skb;
+
+	skb = wimax_msg_alloc(wimax_dev, pipe_name, buf, size, gfp_flags);
+	if (skb == NULL)
+		goto error_msg_new;
+	result = wimax_msg_send(wimax_dev, skb);
+error_msg_new:
+	return result;
+}
+EXPORT_SYMBOL_GPL(wimax_msg);
+
+
+static const
+struct nla_policy wimax_gnl_msg_policy[WIMAX_GNL_ATTR_MAX + 1] = {
+	[WIMAX_GNL_MSG_IFIDX] = {
+		.type = NLA_U32,
+	},
+	[WIMAX_GNL_MSG_DATA] = {
+		.type = NLA_UNSPEC,	/* libnl doesn't grok BINARY yet */
+	},
+};
+
+
+/*
+ * Relays a message from user space to the driver
+ *
+ * The skb is passed to the driver-specific function with the netlink
+ * and generic netlink headers already stripped.
+ *
+ * This call will block while handling/relaying the message.
+ */
+static
+int wimax_gnl_doit_msg_from_user(struct sk_buff *skb, struct genl_info *info)
+{
+	int result, ifindex;
+	struct wimax_dev *wimax_dev;
+	struct device *dev;
+	struct nlmsghdr *nlh = info->nlhdr;
+	char *pipe_name;
+	void *msg_buf;
+	size_t msg_len;
+
+	might_sleep();
+	d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
+	result = -ENODEV;
+	if (info->attrs[WIMAX_GNL_MSG_IFIDX] == NULL) {
+		printk(KERN_ERR "WIMAX_GNL_MSG_FROM_USER: can't find IFIDX "
+		       "attribute\n");
+		goto error_no_wimax_dev;
+	}
+	ifindex = nla_get_u32(info->attrs[WIMAX_GNL_MSG_IFIDX]);
+	wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
+	if (wimax_dev == NULL)
+		goto error_no_wimax_dev;
+	dev = wimax_dev_to_dev(wimax_dev);
+
+	/* Unpack arguments */
+	result = -EINVAL;
+	if (info->attrs[WIMAX_GNL_MSG_DATA] == NULL) {
+		dev_err(dev, "WIMAX_GNL_MSG_FROM_USER: can't find MSG_DATA "
+			"attribute\n");
+		goto error_no_data;
+	}
+	msg_buf = nla_data(info->attrs[WIMAX_GNL_MSG_DATA]);
+	msg_len = nla_len(info->attrs[WIMAX_GNL_MSG_DATA]);
+
+	if (info->attrs[WIMAX_GNL_MSG_PIPE_NAME] == NULL)
+		pipe_name = NULL;
+	else {
+		struct nlattr *attr = info->attrs[WIMAX_GNL_MSG_PIPE_NAME];
+		size_t attr_len = nla_len(attr);
+		/* libnl-1.1 does not yet support NLA_NUL_STRING */
+		result = -ENOMEM;
+		pipe_name = kstrndup(nla_data(attr), attr_len + 1, GFP_KERNEL);
+		if (pipe_name == NULL)
+			goto error_alloc;
+		pipe_name[attr_len] = 0;
+	}
+	mutex_lock(&wimax_dev->mutex);
+	result = wimax_dev_is_ready(wimax_dev);
+	if (result < 0)
+		goto error_not_ready;
+	result = -ENOSYS;
+	if (wimax_dev->op_msg_from_user == NULL)
+		goto error_noop;
+
+	d_printf(1, dev,
+		 "CRX: nlmsghdr len %u type %u flags 0x%04x seq 0x%x pid %u\n",
+		 nlh->nlmsg_len, nlh->nlmsg_type, nlh->nlmsg_flags,
+		 nlh->nlmsg_seq, nlh->nlmsg_pid);
+	d_printf(1, dev, "CRX: wimax message %zu bytes\n", msg_len);
+	d_dump(2, dev, msg_buf, msg_len);
+
+	result = wimax_dev->op_msg_from_user(wimax_dev, pipe_name,
+					     msg_buf, msg_len, info);
+error_noop:
+error_not_ready:
+	mutex_unlock(&wimax_dev->mutex);
+error_alloc:
+	kfree(pipe_name);
+error_no_data:
+	dev_put(wimax_dev->net_dev);
+error_no_wimax_dev:
+	d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
+	return result;
+}
+
+
+/*
+ * Generic Netlink glue
+ */
+
+struct genl_ops wimax_gnl_msg_from_user = {
+	.cmd = WIMAX_GNL_OP_MSG_FROM_USER,
+	.flags = GENL_ADMIN_PERM,
+	.policy = wimax_gnl_msg_policy,
+	.doit = wimax_gnl_doit_msg_from_user,
+	.dumpit = NULL,
+};
+