1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
6 #include <linux/slab.h>
7 #include <linux/skbuff.h>
8 #include <linux/netlink.h>
9 #include <linux/connector.h>
11 #include "w1_internal.h"
12 #include "w1_netlink.h"
14 #if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
16 /* Bundle together everything required to process a request in one memory
21 u32 portid; /* Sending process port ID */
22 /* maximum value for first_cn->len */
24 /* pointers to building up the reply message */
25 struct cn_msg *first_cn; /* fixed once the structure is populated */
26 struct cn_msg *cn; /* advances as cn_msg is appeneded */
27 struct w1_netlink_msg *msg; /* advances as w1_netlink_msg is appened */
28 struct w1_netlink_cmd *cmd; /* advances as cmds are appened */
29 struct w1_netlink_msg *cur_msg; /* currently message being processed */
30 /* copy of the original request follows */
31 struct cn_msg request_cn;
32 /* followed by variable length:
33 * cn_msg, data (w1_netlink_msg and w1_netlink_cmd)
34 * one or more struct w1_cb_node
35 * reply first_cn, data (w1_netlink_msg and w1_netlink_cmd)
39 struct w1_async_cmd async;
40 /* pointers within w1_cb_block and cn data */
41 struct w1_cb_block *block;
42 struct w1_netlink_msg *msg;
44 struct w1_master *dev;
48 * w1_reply_len() - calculate current reply length, compare to maxlen
49 * @block: block to calculate
51 * Calculates the current message length including possible multiple
52 * cn_msg and data, excludes the first sizeof(struct cn_msg). Direclty
53 * compariable to maxlen and usable to send the message.
55 static u16 w1_reply_len(struct w1_cb_block *block)
59 return (u8 *)block->cn - (u8 *)block->first_cn + block->cn->len;
62 static void w1_unref_block(struct w1_cb_block *block)
64 if (atomic_sub_return(1, &block->refcnt) == 0) {
65 u16 len = w1_reply_len(block);
67 cn_netlink_send_mult(block->first_cn, len,
68 block->portid, 0, GFP_KERNEL);
75 * w1_reply_make_space() - send message if needed to make space
76 * @block: block to make space on
77 * @space: how many bytes requested
79 * Verify there is enough room left for the caller to add "space" bytes to the
80 * message, if there isn't send the message and reset.
82 static void w1_reply_make_space(struct w1_cb_block *block, u16 space)
84 u16 len = w1_reply_len(block);
85 if (len + space >= block->maxlen) {
86 cn_netlink_send_mult(block->first_cn, len, block->portid, 0, GFP_KERNEL);
87 block->first_cn->len = 0;
94 /* Early send when replies aren't bundled. */
95 static void w1_netlink_check_send(struct w1_cb_block *block)
97 if (!(block->request_cn.flags & W1_CN_BUNDLE) && block->cn)
98 w1_reply_make_space(block, block->maxlen);
102 * w1_netlink_setup_msg() - prepare to write block->msg
103 * @block: block to operate on
104 * @ack: determines if cn can be reused
106 * block->cn will be setup with the correct ack, advancing if needed
107 * block->cn->len does not include space for block->msg
108 * block->msg advances but remains uninitialized
110 static void w1_netlink_setup_msg(struct w1_cb_block *block, u32 ack)
112 if (block->cn && block->cn->ack == ack) {
113 block->msg = (struct w1_netlink_msg *)(block->cn->data + block->cn->len);
115 /* advance or set to data */
117 block->cn = (struct cn_msg *)(block->cn->data +
120 block->cn = block->first_cn;
122 memcpy(block->cn, &block->request_cn, sizeof(*block->cn));
124 block->cn->ack = ack;
125 block->msg = (struct w1_netlink_msg *)block->cn->data;
129 /* Append cmd to msg, include cmd->data as well. This is because
130 * any following data goes with the command and in the case of a read is
133 static void w1_netlink_queue_cmd(struct w1_cb_block *block,
134 struct w1_netlink_cmd *cmd)
137 w1_reply_make_space(block, sizeof(struct cn_msg) +
138 sizeof(struct w1_netlink_msg) + sizeof(*cmd) + cmd->len);
140 /* There's a status message sent after each command, so no point
141 * in trying to bundle this cmd after an existing one, because
142 * there won't be one. Allocate and copy over a new cn_msg.
144 w1_netlink_setup_msg(block, block->request_cn.seq + 1);
145 memcpy(block->msg, block->cur_msg, sizeof(*block->msg));
146 block->cn->len += sizeof(*block->msg);
148 block->cmd = (struct w1_netlink_cmd *)(block->msg->data);
150 space = sizeof(*cmd) + cmd->len;
151 if (block->cmd != cmd)
152 memcpy(block->cmd, cmd, space);
153 block->cn->len += space;
154 block->msg->len += space;
157 /* Append req_msg and req_cmd, no other commands and no data from req_cmd are
160 static void w1_netlink_queue_status(struct w1_cb_block *block,
161 struct w1_netlink_msg *req_msg, struct w1_netlink_cmd *req_cmd,
164 u16 space = sizeof(struct cn_msg) + sizeof(*req_msg) + sizeof(*req_cmd);
165 w1_reply_make_space(block, space);
166 w1_netlink_setup_msg(block, block->request_cn.ack);
168 memcpy(block->msg, req_msg, sizeof(*req_msg));
169 block->cn->len += sizeof(*req_msg);
171 block->msg->status = (u8)-error;
173 struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)block->msg->data;
174 memcpy(cmd, req_cmd, sizeof(*cmd));
175 block->cn->len += sizeof(*cmd);
176 block->msg->len += sizeof(*cmd);
179 w1_netlink_check_send(block);
183 * w1_netlink_send_error() - sends the error message now
184 * @cn: original cn_msg
185 * @msg: original w1_netlink_msg
186 * @portid: where to send it
187 * @error: error status
189 * Use when a block isn't available to queue the message to and cn, msg
190 * might not be contiguous.
192 static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg,
193 int portid, int error)
197 struct w1_netlink_msg msg;
199 memcpy(&packet.cn, cn, sizeof(packet.cn));
200 memcpy(&packet.msg, msg, sizeof(packet.msg));
201 packet.cn.len = sizeof(packet.msg);
203 packet.msg.status = (u8)-error;
204 cn_netlink_send(&packet.cn, portid, 0, GFP_KERNEL);
208 * w1_netlink_send() - sends w1 netlink notifications
209 * @dev: w1_master the even is associated with or for
210 * @msg: w1_netlink_msg message to be sent
212 * This are notifications generated from the kernel.
214 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
218 struct w1_netlink_msg msg;
220 memset(&packet, 0, sizeof(packet));
222 packet.cn.id.idx = CN_W1_IDX;
223 packet.cn.id.val = CN_W1_VAL;
225 packet.cn.seq = dev->seq++;
226 packet.cn.len = sizeof(*msg);
228 memcpy(&packet.msg, msg, sizeof(*msg));
231 cn_netlink_send(&packet.cn, 0, 0, GFP_KERNEL);
234 static void w1_send_slave(struct w1_master *dev, u64 rn)
236 struct w1_cb_block *block = dev->priv;
237 struct w1_netlink_cmd *cache_cmd = block->cmd;
240 w1_reply_make_space(block, sizeof(*data));
242 /* Add cmd back if the packet was sent */
245 w1_netlink_queue_cmd(block, cache_cmd);
248 data = (u64 *)(block->cmd->data + block->cmd->len);
251 block->cn->len += sizeof(*data);
252 block->msg->len += sizeof(*data);
253 block->cmd->len += sizeof(*data);
256 static void w1_found_send_slave(struct w1_master *dev, u64 rn)
258 /* update kernel slave list */
259 w1_slave_found(dev, rn);
261 w1_send_slave(dev, rn);
264 /* Get the current slave list, or search (with or without alarm) */
265 static int w1_get_slaves(struct w1_master *dev, struct w1_netlink_cmd *req_cmd)
270 w1_netlink_queue_cmd(dev->priv, req_cmd);
272 if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
274 mutex_lock(&dev->list_mutex);
275 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
276 memcpy(&rn, &sl->reg_num, sizeof(rn));
277 w1_send_slave(dev, rn);
279 mutex_unlock(&dev->list_mutex);
281 w1_search_process_cb(dev, req_cmd->cmd == W1_CMD_ALARM_SEARCH ?
282 W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
288 static int w1_process_command_io(struct w1_master *dev,
289 struct w1_netlink_cmd *cmd)
295 w1_touch_block(dev, cmd->data, cmd->len);
296 w1_netlink_queue_cmd(dev->priv, cmd);
299 w1_read_block(dev, cmd->data, cmd->len);
300 w1_netlink_queue_cmd(dev->priv, cmd);
303 w1_write_block(dev, cmd->data, cmd->len);
313 static int w1_process_command_addremove(struct w1_master *dev,
314 struct w1_netlink_cmd *cmd)
318 struct w1_reg_num *id;
320 if (cmd->len != sizeof(*id))
323 id = (struct w1_reg_num *)cmd->data;
325 sl = w1_slave_search_device(dev, id);
327 case W1_CMD_SLAVE_ADD:
331 err = w1_attach_slave_device(dev, id);
333 case W1_CMD_SLAVE_REMOVE:
347 static int w1_process_command_master(struct w1_master *dev,
348 struct w1_netlink_cmd *req_cmd)
352 /* drop bus_mutex for search (does it's own locking), and add/remove
353 * which doesn't use the bus
355 switch (req_cmd->cmd) {
357 case W1_CMD_ALARM_SEARCH:
358 case W1_CMD_LIST_SLAVES:
359 mutex_unlock(&dev->bus_mutex);
360 err = w1_get_slaves(dev, req_cmd);
361 mutex_lock(&dev->bus_mutex);
366 err = w1_process_command_io(dev, req_cmd);
369 err = w1_reset_bus(dev);
371 case W1_CMD_SLAVE_ADD:
372 case W1_CMD_SLAVE_REMOVE:
373 mutex_unlock(&dev->bus_mutex);
374 mutex_lock(&dev->mutex);
375 err = w1_process_command_addremove(dev, req_cmd);
376 mutex_unlock(&dev->mutex);
377 mutex_lock(&dev->bus_mutex);
387 static int w1_process_command_slave(struct w1_slave *sl,
388 struct w1_netlink_cmd *cmd)
390 dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
391 __func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
392 sl->reg_num.crc, cmd->cmd, cmd->len);
394 return w1_process_command_io(sl->master, cmd);
397 static int w1_process_command_root(struct cn_msg *req_cn, u32 portid)
399 struct w1_master *dev;
401 struct w1_netlink_msg *msg;
404 cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
408 cn->id.idx = CN_W1_IDX;
409 cn->id.val = CN_W1_VAL;
411 cn->seq = req_cn->seq;
412 cn->ack = req_cn->seq + 1;
413 cn->len = sizeof(struct w1_netlink_msg);
414 msg = (struct w1_netlink_msg *)cn->data;
416 msg->type = W1_LIST_MASTERS;
419 id = (u32 *)msg->data;
421 mutex_lock(&w1_mlock);
422 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
423 if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
424 cn_netlink_send(cn, portid, 0, GFP_KERNEL);
425 cn->len = sizeof(struct w1_netlink_msg);
427 id = (u32 *)msg->data;
431 msg->len += sizeof(*id);
432 cn->len += sizeof(*id);
435 cn_netlink_send(cn, portid, 0, GFP_KERNEL);
436 mutex_unlock(&w1_mlock);
442 static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
444 struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
446 u16 mlen = node->msg->len;
449 struct w1_slave *sl = node->sl;
450 struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)node->msg->data;
452 mutex_lock(&dev->bus_mutex);
453 dev->priv = node->block;
454 if (sl && w1_reset_select_slave(sl))
456 node->block->cur_msg = node->msg;
458 while (mlen && !err) {
459 if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
465 err = w1_process_command_slave(sl, cmd);
467 err = w1_process_command_master(dev, cmd);
468 w1_netlink_check_send(node->block);
470 w1_netlink_queue_status(node->block, node->msg, cmd, err);
473 len = sizeof(*cmd) + cmd->len;
474 cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
479 w1_netlink_queue_status(node->block, node->msg, cmd, err);
481 /* ref taken in w1_search_slave or w1_search_master_id when building
487 atomic_dec(&dev->refcnt);
489 mutex_unlock(&dev->bus_mutex);
491 mutex_lock(&dev->list_mutex);
492 list_del(&async_cmd->async_entry);
493 mutex_unlock(&dev->list_mutex);
495 w1_unref_block(node->block);
498 static void w1_list_count_cmds(struct w1_netlink_msg *msg, int *cmd_count,
501 struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)msg->data;
506 if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen)
511 case W1_CMD_ALARM_SEARCH:
512 case W1_CMD_LIST_SLAVES:
516 len = sizeof(*cmd) + cmd->len;
517 cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
522 struct w1_master *dev = w1_search_master_id(msg->id.mst.id);
524 /* Bytes, and likely an overstimate, and if it isn't
525 * the results can still be split between packets.
527 *slave_len += sizeof(struct w1_reg_num) * slave_list *
528 (dev->slave_count + dev->max_slave_count);
529 /* search incremented it */
530 atomic_dec(&dev->refcnt);
535 static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp)
537 struct w1_netlink_msg *msg = (struct w1_netlink_msg *)(cn + 1);
539 struct w1_master *dev;
543 struct w1_cb_block *block = NULL;
544 struct w1_cb_node *node = NULL;
548 /* If any unknown flag is set let the application know, that way
549 * applications can detect the absence of features in kernels that
550 * don't know about them. http://lwn.net/Articles/587527/
552 if (cn->flags & ~(W1_CN_BUNDLE)) {
553 w1_netlink_send_error(cn, msg, nsp->portid, -EINVAL);
557 /* Count the number of master or slave commands there are to allocate
558 * space for one cb_node each.
561 while (msg_len && !err) {
562 if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {
567 /* count messages for nodes and allocate any additional space
568 * required for slave lists
570 if (msg->type == W1_MASTER_CMD || msg->type == W1_SLAVE_CMD) {
572 w1_list_count_cmds(msg, &cmd_count, &slave_len);
575 msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
576 msg = (struct w1_netlink_msg *)(((u8 *)msg) +
577 sizeof(struct w1_netlink_msg) + msg->len);
579 msg = (struct w1_netlink_msg *)(cn + 1);
582 int reply_size = sizeof(*cn) + cn->len + slave_len;
583 if (cn->flags & W1_CN_BUNDLE) {
584 /* bundling duplicats some of the messages */
585 reply_size += 2 * cmd_count * (sizeof(struct cn_msg) +
586 sizeof(struct w1_netlink_msg) +
587 sizeof(struct w1_netlink_cmd));
589 reply_size = min(CONNECTOR_MAX_MSG_SIZE, reply_size);
591 /* allocate space for the block, a copy of the original message,
592 * one node per cmd to point into the original message,
593 * space for replies which is the original message size plus
594 * space for any list slave data and status messages
595 * cn->len doesn't include itself which is part of the block
597 size = /* block + original message */
598 sizeof(struct w1_cb_block) + sizeof(*cn) + cn->len +
599 /* space for nodes */
600 node_count * sizeof(struct w1_cb_node) +
602 sizeof(struct cn_msg) + reply_size;
603 block = kzalloc(size, GFP_KERNEL);
605 /* if the system is already out of memory,
606 * (A) will this work, and (B) would it be better
609 w1_netlink_send_error(cn, msg, nsp->portid, -ENOMEM);
612 atomic_set(&block->refcnt, 1);
613 block->portid = nsp->portid;
614 memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len);
615 node = (struct w1_cb_node *)(block->request_cn.data + cn->len);
617 /* Sneeky, when not bundling, reply_size is the allocated space
618 * required for the reply, cn_msg isn't part of maxlen so
619 * it should be reply_size - sizeof(struct cn_msg), however
620 * when checking if there is enough space, w1_reply_make_space
621 * is called with the full message size including cn_msg,
622 * because it isn't known at that time if an additional cn_msg
623 * will need to be allocated. So an extra cn_msg is added
626 block->maxlen = reply_size;
627 block->first_cn = (struct cn_msg *)(node + node_count);
628 memset(block->first_cn, 0, sizeof(*block->first_cn));
632 while (msg_len && !err) {
637 if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {
642 /* execute on this thread, no need to process later */
643 if (msg->type == W1_LIST_MASTERS) {
644 err = w1_process_command_root(cn, nsp->portid);
648 /* All following message types require additional data,
649 * check here before references are taken.
656 /* both search calls take references */
657 if (msg->type == W1_MASTER_CMD) {
658 dev = w1_search_master_id(msg->id.mst.id);
659 } else if (msg->type == W1_SLAVE_CMD) {
660 sl = w1_search_slave((struct w1_reg_num *)msg->id.id);
664 pr_notice("%s: cn: %x.%x, wrong type: %u, len: %u.\n",
665 __func__, cn->id.idx, cn->id.val,
666 msg->type, msg->len);
678 atomic_inc(&block->refcnt);
679 node->async.cb = w1_process_cb;
681 node->msg = (struct w1_netlink_msg *)((u8 *)&block->request_cn +
682 (size_t)((u8 *)msg - (u8 *)cn));
686 mutex_lock(&dev->list_mutex);
687 list_add_tail(&node->async.async_entry, &dev->async_list);
688 wake_up_process(dev->thread);
689 mutex_unlock(&dev->list_mutex);
693 /* Can't queue because that modifies block and another
694 * thread could be processing the messages by now and
695 * there isn't a lock, send directly.
698 w1_netlink_send_error(cn, msg, nsp->portid, err);
699 msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
700 msg = (struct w1_netlink_msg *)(((u8 *)msg) +
701 sizeof(struct w1_netlink_msg) + msg->len);
704 * Let's allow requests for nonexisting devices.
710 w1_unref_block(block);
713 int w1_init_netlink(void)
715 struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
717 return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
720 void w1_fini_netlink(void)
722 struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
724 cn_del_callback(&w1_id);
727 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *cn)
731 int w1_init_netlink(void)
736 void w1_fini_netlink(void)