diff options
Diffstat (limited to 'drivers/w1/w1_netlink.c')
| -rw-r--r-- | drivers/w1/w1_netlink.c | 742 |
1 files changed, 742 insertions, 0 deletions
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c new file mode 100644 index 000000000..691978cdd --- /dev/null +++ b/drivers/w1/w1_netlink.c @@ -0,0 +1,742 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net> + */ + +#include <linux/slab.h> +#include <linux/skbuff.h> +#include <linux/netlink.h> +#include <linux/connector.h> + +#include "w1_internal.h" +#include "w1_netlink.h" + +#if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE))) + +/* Bundle together everything required to process a request in one memory + * allocation. + */ +struct w1_cb_block { + atomic_t refcnt; + u32 portid; /* Sending process port ID */ + /* maximum value for first_cn->len */ + u16 maxlen; + /* pointers to building up the reply message */ + struct cn_msg *first_cn; /* fixed once the structure is populated */ + struct cn_msg *cn; /* advances as cn_msg is appeneded */ + struct w1_netlink_msg *msg; /* advances as w1_netlink_msg is appened */ + struct w1_netlink_cmd *cmd; /* advances as cmds are appened */ + struct w1_netlink_msg *cur_msg; /* currently message being processed */ + /* copy of the original request follows */ + struct cn_msg request_cn; + /* followed by variable length: + * cn_msg, data (w1_netlink_msg and w1_netlink_cmd) + * one or more struct w1_cb_node + * reply first_cn, data (w1_netlink_msg and w1_netlink_cmd) + */ +}; +struct w1_cb_node { + struct w1_async_cmd async; + /* pointers within w1_cb_block and cn data */ + struct w1_cb_block *block; + struct w1_netlink_msg *msg; + struct w1_slave *sl; + struct w1_master *dev; +}; + +/** + * w1_reply_len() - calculate current reply length, compare to maxlen + * @block: block to calculate + * + * Calculates the current message length including possible multiple + * cn_msg and data, excludes the first sizeof(struct cn_msg). Direclty + * compariable to maxlen and usable to send the message. + */ +static u16 w1_reply_len(struct w1_cb_block *block) +{ + if (!block->cn) + return 0; + return (u8 *)block->cn - (u8 *)block->first_cn + block->cn->len; +} + +static void w1_unref_block(struct w1_cb_block *block) +{ + if (atomic_sub_return(1, &block->refcnt) == 0) { + u16 len = w1_reply_len(block); + if (len) { + cn_netlink_send_mult(block->first_cn, len, + block->portid, 0, + GFP_KERNEL, NULL, NULL); + } + kfree(block); + } +} + +/** + * w1_reply_make_space() - send message if needed to make space + * @block: block to make space on + * @space: how many bytes requested + * + * Verify there is enough room left for the caller to add "space" bytes to the + * message, if there isn't send the message and reset. + */ +static void w1_reply_make_space(struct w1_cb_block *block, u16 space) +{ + u16 len = w1_reply_len(block); + if (len + space >= block->maxlen) { + cn_netlink_send_mult(block->first_cn, len, block->portid, + 0, GFP_KERNEL, NULL, NULL); + block->first_cn->len = 0; + block->cn = NULL; + block->msg = NULL; + block->cmd = NULL; + } +} + +/* Early send when replies aren't bundled. */ +static void w1_netlink_check_send(struct w1_cb_block *block) +{ + if (!(block->request_cn.flags & W1_CN_BUNDLE) && block->cn) + w1_reply_make_space(block, block->maxlen); +} + +/** + * w1_netlink_setup_msg() - prepare to write block->msg + * @block: block to operate on + * @ack: determines if cn can be reused + * + * block->cn will be setup with the correct ack, advancing if needed + * block->cn->len does not include space for block->msg + * block->msg advances but remains uninitialized + */ +static void w1_netlink_setup_msg(struct w1_cb_block *block, u32 ack) +{ + if (block->cn && block->cn->ack == ack) { + block->msg = (struct w1_netlink_msg *)(block->cn->data + block->cn->len); + } else { + /* advance or set to data */ + if (block->cn) + block->cn = (struct cn_msg *)(block->cn->data + + block->cn->len); + else + block->cn = block->first_cn; + + memcpy(block->cn, &block->request_cn, sizeof(*block->cn)); + block->cn->len = 0; + block->cn->ack = ack; + block->msg = (struct w1_netlink_msg *)block->cn->data; + } +} + +/* Append cmd to msg, include cmd->data as well. This is because + * any following data goes with the command and in the case of a read is + * the results. + */ +static void w1_netlink_queue_cmd(struct w1_cb_block *block, + struct w1_netlink_cmd *cmd) +{ + u32 space; + w1_reply_make_space(block, sizeof(struct cn_msg) + + sizeof(struct w1_netlink_msg) + sizeof(*cmd) + cmd->len); + + /* There's a status message sent after each command, so no point + * in trying to bundle this cmd after an existing one, because + * there won't be one. Allocate and copy over a new cn_msg. + */ + w1_netlink_setup_msg(block, block->request_cn.seq + 1); + memcpy(block->msg, block->cur_msg, sizeof(*block->msg)); + block->cn->len += sizeof(*block->msg); + block->msg->len = 0; + block->cmd = (struct w1_netlink_cmd *)(block->msg->data); + + space = sizeof(*cmd) + cmd->len; + if (block->cmd != cmd) + memcpy(block->cmd, cmd, space); + block->cn->len += space; + block->msg->len += space; +} + +/* Append req_msg and req_cmd, no other commands and no data from req_cmd are + * copied. + */ +static void w1_netlink_queue_status(struct w1_cb_block *block, + struct w1_netlink_msg *req_msg, struct w1_netlink_cmd *req_cmd, + int error) +{ + u16 space = sizeof(struct cn_msg) + sizeof(*req_msg) + sizeof(*req_cmd); + w1_reply_make_space(block, space); + w1_netlink_setup_msg(block, block->request_cn.ack); + + memcpy(block->msg, req_msg, sizeof(*req_msg)); + block->cn->len += sizeof(*req_msg); + block->msg->len = 0; + block->msg->status = (u8)-error; + if (req_cmd) { + struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)block->msg->data; + memcpy(cmd, req_cmd, sizeof(*cmd)); + block->cn->len += sizeof(*cmd); + block->msg->len += sizeof(*cmd); + cmd->len = 0; + } + w1_netlink_check_send(block); +} + +/** + * w1_netlink_send_error() - sends the error message now + * @cn: original cn_msg + * @msg: original w1_netlink_msg + * @portid: where to send it + * @error: error status + * + * Use when a block isn't available to queue the message to and cn, msg + * might not be contiguous. + */ +static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg, + int portid, int error) +{ + struct { + struct cn_msg cn; + struct w1_netlink_msg msg; + } packet; + memcpy(&packet.cn, cn, sizeof(packet.cn)); + memcpy(&packet.msg, msg, sizeof(packet.msg)); + packet.cn.len = sizeof(packet.msg); + packet.msg.len = 0; + packet.msg.status = (u8)-error; + cn_netlink_send(&packet.cn, portid, 0, GFP_KERNEL); +} + +/** + * w1_netlink_send() - sends w1 netlink notifications + * @dev: w1_master the even is associated with or for + * @msg: w1_netlink_msg message to be sent + * + * This are notifications generated from the kernel. + */ +void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg) +{ + struct { + struct cn_msg cn; + struct w1_netlink_msg msg; + } packet; + memset(&packet, 0, sizeof(packet)); + + packet.cn.id.idx = CN_W1_IDX; + packet.cn.id.val = CN_W1_VAL; + + packet.cn.seq = dev->seq++; + packet.cn.len = sizeof(*msg); + + memcpy(&packet.msg, msg, sizeof(*msg)); + packet.msg.len = 0; + + cn_netlink_send(&packet.cn, 0, 0, GFP_KERNEL); +} + +static void w1_send_slave(struct w1_master *dev, u64 rn) +{ + struct w1_cb_block *block = dev->priv; + struct w1_netlink_cmd *cache_cmd = block->cmd; + u64 *data; + + w1_reply_make_space(block, sizeof(*data)); + + /* Add cmd back if the packet was sent */ + if (!block->cmd) { + cache_cmd->len = 0; + w1_netlink_queue_cmd(block, cache_cmd); + } + + data = (u64 *)(block->cmd->data + block->cmd->len); + + *data = rn; + block->cn->len += sizeof(*data); + block->msg->len += sizeof(*data); + block->cmd->len += sizeof(*data); +} + +static void w1_found_send_slave(struct w1_master *dev, u64 rn) +{ + /* update kernel slave list */ + w1_slave_found(dev, rn); + + w1_send_slave(dev, rn); +} + +/* Get the current slave list, or search (with or without alarm) */ +static int w1_get_slaves(struct w1_master *dev, struct w1_netlink_cmd *req_cmd) +{ + struct w1_slave *sl; + + req_cmd->len = 0; + w1_netlink_queue_cmd(dev->priv, req_cmd); + + if (req_cmd->cmd == W1_CMD_LIST_SLAVES) { + u64 rn; + mutex_lock(&dev->list_mutex); + list_for_each_entry(sl, &dev->slist, w1_slave_entry) { + memcpy(&rn, &sl->reg_num, sizeof(rn)); + w1_send_slave(dev, rn); + } + mutex_unlock(&dev->list_mutex); + } else { + w1_search_process_cb(dev, req_cmd->cmd == W1_CMD_ALARM_SEARCH ? + W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave); + } + + return 0; +} + +static int w1_process_command_io(struct w1_master *dev, + struct w1_netlink_cmd *cmd) +{ + int err = 0; + + switch (cmd->cmd) { + case W1_CMD_TOUCH: + w1_touch_block(dev, cmd->data, cmd->len); + w1_netlink_queue_cmd(dev->priv, cmd); + break; + case W1_CMD_READ: + w1_read_block(dev, cmd->data, cmd->len); + w1_netlink_queue_cmd(dev->priv, cmd); + break; + case W1_CMD_WRITE: + w1_write_block(dev, cmd->data, cmd->len); + break; + default: + err = -EINVAL; + break; + } + + return err; +} + +static int w1_process_command_addremove(struct w1_master *dev, + struct w1_netlink_cmd *cmd) +{ + struct w1_slave *sl; + int err = 0; + struct w1_reg_num *id; + + if (cmd->len != sizeof(*id)) + return -EINVAL; + + id = (struct w1_reg_num *)cmd->data; + + sl = w1_slave_search_device(dev, id); + switch (cmd->cmd) { + case W1_CMD_SLAVE_ADD: + if (sl) + err = -EINVAL; + else + err = w1_attach_slave_device(dev, id); + break; + case W1_CMD_SLAVE_REMOVE: + if (sl) + w1_slave_detach(sl); + else + err = -EINVAL; + break; + default: + err = -EINVAL; + break; + } + + return err; +} + +static int w1_process_command_master(struct w1_master *dev, + struct w1_netlink_cmd *req_cmd) +{ + int err = -EINVAL; + + /* drop bus_mutex for search (does it's own locking), and add/remove + * which doesn't use the bus + */ + switch (req_cmd->cmd) { + case W1_CMD_SEARCH: + case W1_CMD_ALARM_SEARCH: + case W1_CMD_LIST_SLAVES: + mutex_unlock(&dev->bus_mutex); + err = w1_get_slaves(dev, req_cmd); + mutex_lock(&dev->bus_mutex); + break; + case W1_CMD_READ: + case W1_CMD_WRITE: + case W1_CMD_TOUCH: + err = w1_process_command_io(dev, req_cmd); + break; + case W1_CMD_RESET: + err = w1_reset_bus(dev); + break; + case W1_CMD_SLAVE_ADD: + case W1_CMD_SLAVE_REMOVE: + mutex_unlock(&dev->bus_mutex); + mutex_lock(&dev->mutex); + err = w1_process_command_addremove(dev, req_cmd); + mutex_unlock(&dev->mutex); + mutex_lock(&dev->bus_mutex); + break; + default: + err = -EINVAL; + break; + } + + return err; +} + +static int w1_process_command_slave(struct w1_slave *sl, + struct w1_netlink_cmd *cmd) +{ + dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n", + __func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id, + sl->reg_num.crc, cmd->cmd, cmd->len); + + return w1_process_command_io(sl->master, cmd); +} + +static int w1_process_command_root(struct cn_msg *req_cn, u32 portid) +{ + struct w1_master *dev; + struct cn_msg *cn; + struct w1_netlink_msg *msg; + u32 *id; + + cn = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!cn) + return -ENOMEM; + + cn->id.idx = CN_W1_IDX; + cn->id.val = CN_W1_VAL; + + cn->seq = req_cn->seq; + cn->ack = req_cn->seq + 1; + cn->len = sizeof(struct w1_netlink_msg); + msg = (struct w1_netlink_msg *)cn->data; + + msg->type = W1_LIST_MASTERS; + msg->status = 0; + msg->len = 0; + id = (u32 *)msg->data; + + mutex_lock(&w1_mlock); + list_for_each_entry(dev, &w1_masters, w1_master_entry) { + if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) { + cn_netlink_send(cn, portid, 0, GFP_KERNEL); + cn->len = sizeof(struct w1_netlink_msg); + msg->len = 0; + id = (u32 *)msg->data; + } + + *id = dev->id; + msg->len += sizeof(*id); + cn->len += sizeof(*id); + id++; + } + cn_netlink_send(cn, portid, 0, GFP_KERNEL); + mutex_unlock(&w1_mlock); + + kfree(cn); + return 0; +} + +static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd) +{ + struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node, + async); + u16 mlen = node->msg->len; + u16 len; + int err = 0; + struct w1_slave *sl = node->sl; + struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)node->msg->data; + + mutex_lock(&dev->bus_mutex); + dev->priv = node->block; + if (sl && w1_reset_select_slave(sl)) + err = -ENODEV; + node->block->cur_msg = node->msg; + + while (mlen && !err) { + if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) { + err = -E2BIG; + break; + } + + if (sl) + err = w1_process_command_slave(sl, cmd); + else + err = w1_process_command_master(dev, cmd); + w1_netlink_check_send(node->block); + + w1_netlink_queue_status(node->block, node->msg, cmd, err); + err = 0; + + len = sizeof(*cmd) + cmd->len; + cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len); + mlen -= len; + } + + if (!cmd || err) + w1_netlink_queue_status(node->block, node->msg, cmd, err); + + /* ref taken in w1_search_slave or w1_search_master_id when building + * the block + */ + if (sl) + w1_unref_slave(sl); + else + atomic_dec(&dev->refcnt); + dev->priv = NULL; + mutex_unlock(&dev->bus_mutex); + + mutex_lock(&dev->list_mutex); + list_del(&async_cmd->async_entry); + mutex_unlock(&dev->list_mutex); + + w1_unref_block(node->block); +} + +static void w1_list_count_cmds(struct w1_netlink_msg *msg, int *cmd_count, + u16 *slave_len) +{ + struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)msg->data; + u16 mlen = msg->len; + u16 len; + int slave_list = 0; + while (mlen) { + if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) + break; + + switch (cmd->cmd) { + case W1_CMD_SEARCH: + case W1_CMD_ALARM_SEARCH: + case W1_CMD_LIST_SLAVES: + ++slave_list; + } + ++*cmd_count; + len = sizeof(*cmd) + cmd->len; + cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len); + mlen -= len; + } + + if (slave_list) { + struct w1_master *dev = w1_search_master_id(msg->id.mst.id); + if (dev) { + /* Bytes, and likely an overstimate, and if it isn't + * the results can still be split between packets. + */ + *slave_len += sizeof(struct w1_reg_num) * slave_list * + (dev->slave_count + dev->max_slave_count); + /* search incremented it */ + atomic_dec(&dev->refcnt); + } + } +} + +static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp) +{ + struct w1_netlink_msg *msg = (struct w1_netlink_msg *)(cn + 1); + struct w1_slave *sl; + struct w1_master *dev; + u16 msg_len; + u16 slave_len = 0; + int err = 0; + struct w1_cb_block *block = NULL; + struct w1_cb_node *node = NULL; + int node_count = 0; + int cmd_count = 0; + + /* If any unknown flag is set let the application know, that way + * applications can detect the absence of features in kernels that + * don't know about them. http://lwn.net/Articles/587527/ + */ + if (cn->flags & ~(W1_CN_BUNDLE)) { + w1_netlink_send_error(cn, msg, nsp->portid, -EINVAL); + return; + } + + /* Count the number of master or slave commands there are to allocate + * space for one cb_node each. + */ + msg_len = cn->len; + while (msg_len && !err) { + if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) { + err = -E2BIG; + break; + } + + /* count messages for nodes and allocate any additional space + * required for slave lists + */ + if (msg->type == W1_MASTER_CMD || msg->type == W1_SLAVE_CMD) { + ++node_count; + w1_list_count_cmds(msg, &cmd_count, &slave_len); + } + + msg_len -= sizeof(struct w1_netlink_msg) + msg->len; + msg = (struct w1_netlink_msg *)(((u8 *)msg) + + sizeof(struct w1_netlink_msg) + msg->len); + } + msg = (struct w1_netlink_msg *)(cn + 1); + if (node_count) { + int size; + int reply_size = sizeof(*cn) + cn->len + slave_len; + if (cn->flags & W1_CN_BUNDLE) { + /* bundling duplicats some of the messages */ + reply_size += 2 * cmd_count * (sizeof(struct cn_msg) + + sizeof(struct w1_netlink_msg) + + sizeof(struct w1_netlink_cmd)); + } + reply_size = min(CONNECTOR_MAX_MSG_SIZE, reply_size); + + /* allocate space for the block, a copy of the original message, + * one node per cmd to point into the original message, + * space for replies which is the original message size plus + * space for any list slave data and status messages + * cn->len doesn't include itself which is part of the block + * */ + size = /* block + original message */ + sizeof(struct w1_cb_block) + sizeof(*cn) + cn->len + + /* space for nodes */ + node_count * sizeof(struct w1_cb_node) + + /* replies */ + sizeof(struct cn_msg) + reply_size; + block = kzalloc(size, GFP_KERNEL); + if (!block) { + /* if the system is already out of memory, + * (A) will this work, and (B) would it be better + * to not try? + */ + w1_netlink_send_error(cn, msg, nsp->portid, -ENOMEM); + return; + } + atomic_set(&block->refcnt, 1); + block->portid = nsp->portid; + block->request_cn = *cn; + memcpy(block->request_cn.data, cn->data, cn->len); + node = (struct w1_cb_node *)(block->request_cn.data + cn->len); + + /* Sneeky, when not bundling, reply_size is the allocated space + * required for the reply, cn_msg isn't part of maxlen so + * it should be reply_size - sizeof(struct cn_msg), however + * when checking if there is enough space, w1_reply_make_space + * is called with the full message size including cn_msg, + * because it isn't known at that time if an additional cn_msg + * will need to be allocated. So an extra cn_msg is added + * above in "size". + */ + block->maxlen = reply_size; + block->first_cn = (struct cn_msg *)(node + node_count); + memset(block->first_cn, 0, sizeof(*block->first_cn)); + } + + msg_len = cn->len; + while (msg_len && !err) { + + dev = NULL; + sl = NULL; + + if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) { + err = -E2BIG; + break; + } + + /* execute on this thread, no need to process later */ + if (msg->type == W1_LIST_MASTERS) { + err = w1_process_command_root(cn, nsp->portid); + goto out_cont; + } + + /* All following message types require additional data, + * check here before references are taken. + */ + if (!msg->len) { + err = -EPROTO; + goto out_cont; + } + + /* both search calls take references */ + if (msg->type == W1_MASTER_CMD) { + dev = w1_search_master_id(msg->id.mst.id); + } else if (msg->type == W1_SLAVE_CMD) { + sl = w1_search_slave((struct w1_reg_num *)msg->id.id); + if (sl) + dev = sl->master; + } else { + pr_notice("%s: cn: %x.%x, wrong type: %u, len: %u.\n", + __func__, cn->id.idx, cn->id.val, + msg->type, msg->len); + err = -EPROTO; + goto out_cont; + } + + if (!dev) { + err = -ENODEV; + goto out_cont; + } + + err = 0; + + atomic_inc(&block->refcnt); + node->async.cb = w1_process_cb; + node->block = block; + node->msg = (struct w1_netlink_msg *)((u8 *)&block->request_cn + + (size_t)((u8 *)msg - (u8 *)cn)); + node->sl = sl; + node->dev = dev; + + mutex_lock(&dev->list_mutex); + list_add_tail(&node->async.async_entry, &dev->async_list); + wake_up_process(dev->thread); + mutex_unlock(&dev->list_mutex); + ++node; + +out_cont: + /* Can't queue because that modifies block and another + * thread could be processing the messages by now and + * there isn't a lock, send directly. + */ + if (err) + w1_netlink_send_error(cn, msg, nsp->portid, err); + msg_len -= sizeof(struct w1_netlink_msg) + msg->len; + msg = (struct w1_netlink_msg *)(((u8 *)msg) + + sizeof(struct w1_netlink_msg) + msg->len); + + /* + * Let's allow requests for nonexisting devices. + */ + if (err == -ENODEV) + err = 0; + } + if (block) + w1_unref_block(block); +} + +int w1_init_netlink(void) +{ + struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL}; + + return cn_add_callback(&w1_id, "w1", &w1_cn_callback); +} + +void w1_fini_netlink(void) +{ + struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL}; + + cn_del_callback(&w1_id); +} +#else +void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *cn) +{ +} + +int w1_init_netlink(void) +{ + return 0; +} + +void w1_fini_netlink(void) +{ +} +#endif |