/* * 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 <linux/slab.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. * * Unlike other WiMAX stack calls, this call can be used way early, * even before wimax_dev_add() is called, as long as the * wimax_dev->net_dev pointer is set to point to a proper * net_dev. This is so that drivers can use it early in case they need * to send stuff around or communicate with user space. */ 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_to_dev(wimax_dev); 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 (msg %p size %zu) in " "attribute: %d\n", msg, size, result); 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. * * Unlike other WiMAX stack calls, this call can be used way early, * even before wimax_dev_add() is called, as long as the * wimax_dev->net_dev pointer is set to point to a proper * net_dev. This is so that drivers can use it early in case they need * to send stuff around or communicate with user space. */ int wimax_msg_send(struct wimax_dev *wimax_dev, struct sk_buff *skb) { struct device *dev = wimax_dev_to_dev(wimax_dev); 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); genlmsg_multicast(skb, 0, wimax_gnl_mcg.id, GFP_KERNEL); d_printf(1, dev, "CTX: genl multicast done\n"); return 0; } 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 (IS_ERR(skb)) result = PTR_ERR(skb); else result = wimax_msg_send(wimax_dev, skb); 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 == -ENOMEDIUM) result = 0; 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, };