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391 lines
11 KiB
391 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Linux WiMAX |
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* Generic messaging interface between userspace and driver/device |
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* |
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* Copyright (C) 2007-2008 Intel Corporation <[email protected]> |
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* Inaky Perez-Gonzalez <[email protected]> |
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* |
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* This implements a direct communication channel between user space and |
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* the driver/device, by which free form messages can be sent back and |
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* forth. |
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* |
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* This is intended for device-specific features, vendor quirks, etc. |
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* |
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* See include/net/wimax.h |
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* |
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* GENERIC NETLINK ENCODING AND CAPACITY |
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* |
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* A destination "pipe name" is added to each message; it is up to the |
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* drivers to assign or use those names (if using them at all). |
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* |
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* Messages are encoded as a binary netlink attribute using nla_put() |
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* using type NLA_UNSPEC (as some versions of libnl still in |
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* deployment don't yet understand NLA_BINARY). |
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* |
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* The maximum capacity of this transport is PAGESIZE per message (so |
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* the actual payload will be bit smaller depending on the |
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* netlink/generic netlink attributes and headers). |
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* |
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* RECEPTION OF MESSAGES |
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* |
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* When a message is received from user space, it is passed verbatim |
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* to the driver calling wimax_dev->op_msg_from_user(). The return |
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* value from this function is passed back to user space as an ack |
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* over the generic netlink protocol. |
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* |
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* The stack doesn't do any processing or interpretation of these |
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* messages. |
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* |
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* SENDING MESSAGES |
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* |
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* Messages can be sent with wimax_msg(). |
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* |
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* If the message delivery needs to happen on a different context to |
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* that of its creation, wimax_msg_alloc() can be used to get a |
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* pointer to the message that can be delivered later on with |
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* wimax_msg_send(). |
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* |
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* ROADMAP |
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* |
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* wimax_gnl_doit_msg_from_user() Process a message from user space |
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* wimax_dev_get_by_genl_info() |
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* wimax_dev->op_msg_from_user() Delivery of message to the driver |
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* |
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* wimax_msg() Send a message to user space |
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* wimax_msg_alloc() |
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* wimax_msg_send() |
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*/ |
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#include <linux/device.h> |
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#include <linux/slab.h> |
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#include <net/genetlink.h> |
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#include <linux/netdevice.h> |
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#include <linux/wimax.h> |
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#include <linux/security.h> |
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#include <linux/export.h> |
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#include "wimax-internal.h" |
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#define D_SUBMODULE op_msg |
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#include "debug-levels.h" |
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/** |
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* wimax_msg_alloc - Create a new skb for sending a message to userspace |
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* |
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* @wimax_dev: WiMAX device descriptor |
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* @pipe_name: "named pipe" the message will be sent to |
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* @msg: pointer to the message data to send |
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* @size: size of the message to send (in bytes), including the header. |
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* @gfp_flags: flags for memory allocation. |
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* |
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* Returns: %0 if ok, negative errno code on error |
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* |
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* Description: |
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* |
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* Allocates an skb that will contain the message to send to user |
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* space over the messaging pipe and initializes it, copying the |
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* payload. |
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* |
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* Once this call is done, you can deliver it with |
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* wimax_msg_send(). |
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* |
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* IMPORTANT: |
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* |
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* Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as |
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* wimax_msg_send() depends on skb->data being placed at the |
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* beginning of the user message. |
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* |
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* Unlike other WiMAX stack calls, this call can be used way early, |
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* even before wimax_dev_add() is called, as long as the |
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* wimax_dev->net_dev pointer is set to point to a proper |
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* net_dev. This is so that drivers can use it early in case they need |
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* to send stuff around or communicate with user space. |
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*/ |
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struct sk_buff *wimax_msg_alloc(struct wimax_dev *wimax_dev, |
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const char *pipe_name, |
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const void *msg, size_t size, |
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gfp_t gfp_flags) |
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{ |
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int result; |
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struct device *dev = wimax_dev_to_dev(wimax_dev); |
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size_t msg_size; |
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void *genl_msg; |
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struct sk_buff *skb; |
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msg_size = nla_total_size(size) |
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+ nla_total_size(sizeof(u32)) |
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+ (pipe_name ? nla_total_size(strlen(pipe_name)) : 0); |
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result = -ENOMEM; |
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skb = genlmsg_new(msg_size, gfp_flags); |
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if (skb == NULL) |
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goto error_new; |
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genl_msg = genlmsg_put(skb, 0, 0, &wimax_gnl_family, |
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0, WIMAX_GNL_OP_MSG_TO_USER); |
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if (genl_msg == NULL) { |
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dev_err(dev, "no memory to create generic netlink message\n"); |
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goto error_genlmsg_put; |
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} |
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result = nla_put_u32(skb, WIMAX_GNL_MSG_IFIDX, |
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wimax_dev->net_dev->ifindex); |
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if (result < 0) { |
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dev_err(dev, "no memory to add ifindex attribute\n"); |
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goto error_nla_put; |
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} |
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if (pipe_name) { |
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result = nla_put_string(skb, WIMAX_GNL_MSG_PIPE_NAME, |
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pipe_name); |
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if (result < 0) { |
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dev_err(dev, "no memory to add pipe_name attribute\n"); |
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goto error_nla_put; |
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} |
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} |
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result = nla_put(skb, WIMAX_GNL_MSG_DATA, size, msg); |
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if (result < 0) { |
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dev_err(dev, "no memory to add payload (msg %p size %zu) in " |
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"attribute: %d\n", msg, size, result); |
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goto error_nla_put; |
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} |
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genlmsg_end(skb, genl_msg); |
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return skb; |
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error_nla_put: |
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error_genlmsg_put: |
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error_new: |
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nlmsg_free(skb); |
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return ERR_PTR(result); |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg_alloc); |
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/** |
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* wimax_msg_data_len - Return a pointer and size of a message's payload |
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* |
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* @msg: Pointer to a message created with wimax_msg_alloc() |
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* @size: Pointer to where to store the message's size |
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* |
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* Returns the pointer to the message data. |
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*/ |
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const void *wimax_msg_data_len(struct sk_buff *msg, size_t *size) |
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{ |
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struct nlmsghdr *nlh = (void *) msg->head; |
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struct nlattr *nla; |
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nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), |
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WIMAX_GNL_MSG_DATA); |
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if (nla == NULL) { |
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pr_err("Cannot find attribute WIMAX_GNL_MSG_DATA\n"); |
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return NULL; |
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} |
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*size = nla_len(nla); |
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return nla_data(nla); |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg_data_len); |
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/** |
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* wimax_msg_data - Return a pointer to a message's payload |
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* |
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* @msg: Pointer to a message created with wimax_msg_alloc() |
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*/ |
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const void *wimax_msg_data(struct sk_buff *msg) |
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{ |
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struct nlmsghdr *nlh = (void *) msg->head; |
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struct nlattr *nla; |
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nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), |
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WIMAX_GNL_MSG_DATA); |
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if (nla == NULL) { |
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pr_err("Cannot find attribute WIMAX_GNL_MSG_DATA\n"); |
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return NULL; |
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} |
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return nla_data(nla); |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg_data); |
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/** |
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* wimax_msg_len - Return a message's payload length |
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* |
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* @msg: Pointer to a message created with wimax_msg_alloc() |
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*/ |
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ssize_t wimax_msg_len(struct sk_buff *msg) |
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{ |
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struct nlmsghdr *nlh = (void *) msg->head; |
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struct nlattr *nla; |
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nla = nlmsg_find_attr(nlh, sizeof(struct genlmsghdr), |
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WIMAX_GNL_MSG_DATA); |
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if (nla == NULL) { |
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pr_err("Cannot find attribute WIMAX_GNL_MSG_DATA\n"); |
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return -EINVAL; |
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} |
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return nla_len(nla); |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg_len); |
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/** |
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* wimax_msg_send - Send a pre-allocated message to user space |
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* |
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* @wimax_dev: WiMAX device descriptor |
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* |
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* @skb: &struct sk_buff returned by wimax_msg_alloc(). Note the |
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* ownership of @skb is transferred to this function. |
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* |
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* Returns: 0 if ok, < 0 errno code on error |
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* |
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* Description: |
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* |
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* Sends a free-form message that was preallocated with |
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* wimax_msg_alloc() and filled up. |
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* |
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* Assumes that once you pass an skb to this function for sending, it |
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* owns it and will release it when done (on success). |
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* |
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* IMPORTANT: |
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* |
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* Don't use skb_push()/skb_pull()/skb_reserve() on the skb, as |
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* wimax_msg_send() depends on skb->data being placed at the |
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* beginning of the user message. |
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* |
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* Unlike other WiMAX stack calls, this call can be used way early, |
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* even before wimax_dev_add() is called, as long as the |
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* wimax_dev->net_dev pointer is set to point to a proper |
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* net_dev. This is so that drivers can use it early in case they need |
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* to send stuff around or communicate with user space. |
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*/ |
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int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb) |
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{ |
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struct device *dev = wimax_dev_to_dev(wimax_dev); |
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void *msg = skb->data; |
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size_t size = skb->len; |
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might_sleep(); |
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d_printf(1, dev, "CTX: wimax msg, %zu bytes\n", size); |
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d_dump(2, dev, msg, size); |
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genlmsg_multicast(&wimax_gnl_family, skb, 0, 0, GFP_KERNEL); |
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d_printf(1, dev, "CTX: genl multicast done\n"); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg_send); |
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/** |
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* wimax_msg - Send a message to user space |
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* |
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* @wimax_dev: WiMAX device descriptor (properly referenced) |
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* @pipe_name: "named pipe" the message will be sent to |
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* @buf: pointer to the message to send. |
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* @size: size of the buffer pointed to by @buf (in bytes). |
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* @gfp_flags: flags for memory allocation. |
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* |
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* Returns: %0 if ok, negative errno code on error. |
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* |
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* Description: |
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* |
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* Sends a free-form message to user space on the device @wimax_dev. |
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* |
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* NOTES: |
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* |
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* Once the @skb is given to this function, who will own it and will |
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* release it when done (unless it returns error). |
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*/ |
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int wimax_msg(struct wimax_dev *wimax_dev, const char *pipe_name, |
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const void *buf, size_t size, gfp_t gfp_flags) |
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{ |
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int result = -ENOMEM; |
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struct sk_buff *skb; |
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skb = wimax_msg_alloc(wimax_dev, pipe_name, buf, size, gfp_flags); |
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if (IS_ERR(skb)) |
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result = PTR_ERR(skb); |
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else |
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result = wimax_msg_send(wimax_dev, skb); |
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return result; |
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} |
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EXPORT_SYMBOL_GPL(wimax_msg); |
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/* |
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* Relays a message from user space to the driver |
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* |
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* The skb is passed to the driver-specific function with the netlink |
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* and generic netlink headers already stripped. |
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* |
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* This call will block while handling/relaying the message. |
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*/ |
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int wimax_gnl_doit_msg_from_user(struct sk_buff *skb, struct genl_info *info) |
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{ |
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int result, ifindex; |
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struct wimax_dev *wimax_dev; |
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struct device *dev; |
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struct nlmsghdr *nlh = info->nlhdr; |
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char *pipe_name; |
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void *msg_buf; |
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size_t msg_len; |
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might_sleep(); |
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d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info); |
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result = -ENODEV; |
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if (info->attrs[WIMAX_GNL_MSG_IFIDX] == NULL) { |
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pr_err("WIMAX_GNL_MSG_FROM_USER: can't find IFIDX attribute\n"); |
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goto error_no_wimax_dev; |
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} |
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ifindex = nla_get_u32(info->attrs[WIMAX_GNL_MSG_IFIDX]); |
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wimax_dev = wimax_dev_get_by_genl_info(info, ifindex); |
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if (wimax_dev == NULL) |
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goto error_no_wimax_dev; |
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dev = wimax_dev_to_dev(wimax_dev); |
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/* Unpack arguments */ |
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result = -EINVAL; |
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if (info->attrs[WIMAX_GNL_MSG_DATA] == NULL) { |
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dev_err(dev, "WIMAX_GNL_MSG_FROM_USER: can't find MSG_DATA " |
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"attribute\n"); |
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goto error_no_data; |
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} |
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msg_buf = nla_data(info->attrs[WIMAX_GNL_MSG_DATA]); |
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msg_len = nla_len(info->attrs[WIMAX_GNL_MSG_DATA]); |
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if (info->attrs[WIMAX_GNL_MSG_PIPE_NAME] == NULL) |
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pipe_name = NULL; |
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else { |
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struct nlattr *attr = info->attrs[WIMAX_GNL_MSG_PIPE_NAME]; |
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size_t attr_len = nla_len(attr); |
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/* libnl-1.1 does not yet support NLA_NUL_STRING */ |
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result = -ENOMEM; |
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pipe_name = kstrndup(nla_data(attr), attr_len + 1, GFP_KERNEL); |
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if (pipe_name == NULL) |
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goto error_alloc; |
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pipe_name[attr_len] = 0; |
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} |
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mutex_lock(&wimax_dev->mutex); |
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result = wimax_dev_is_ready(wimax_dev); |
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if (result == -ENOMEDIUM) |
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result = 0; |
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if (result < 0) |
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goto error_not_ready; |
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result = -ENOSYS; |
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if (wimax_dev->op_msg_from_user == NULL) |
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goto error_noop; |
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d_printf(1, dev, |
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"CRX: nlmsghdr len %u type %u flags 0x%04x seq 0x%x pid %u\n", |
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nlh->nlmsg_len, nlh->nlmsg_type, nlh->nlmsg_flags, |
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nlh->nlmsg_seq, nlh->nlmsg_pid); |
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d_printf(1, dev, "CRX: wimax message %zu bytes\n", msg_len); |
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d_dump(2, dev, msg_buf, msg_len); |
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result = wimax_dev->op_msg_from_user(wimax_dev, pipe_name, |
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msg_buf, msg_len, info); |
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error_noop: |
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error_not_ready: |
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mutex_unlock(&wimax_dev->mutex); |
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error_alloc: |
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kfree(pipe_name); |
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error_no_data: |
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dev_put(wimax_dev->net_dev); |
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error_no_wimax_dev: |
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d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result); |
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return result; |
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}
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