kernel-hacking-2024-linux-steffo/drivers/w1/w1_netlink.c

/*
 * w1_netlink.c
 *
 * Copyright (c) 2003 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/connector.h>

#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"

#if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
{
	char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
	struct cn_msg *m = (struct cn_msg *)buf;
	struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);

	memset(buf, 0, sizeof(buf));

	m->id.idx = CN_W1_IDX;
	m->id.val = CN_W1_VAL;

	m->seq = dev->seq++;
	m->len = sizeof(struct w1_netlink_msg);

	memcpy(w, msg, sizeof(struct w1_netlink_msg));

	cn_netlink_send(m, 0, GFP_KERNEL);
}

static void w1_send_slave(struct w1_master *dev, u64 rn)
{
	struct cn_msg *msg = dev->priv;
	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
	int avail;

	avail = dev->priv_size - cmd->len;

	if (avail > 8) {
		u64 *data = (void *)(cmd + 1) + cmd->len;

		*data = rn;
		cmd->len += 8;
		hdr->len += 8;
		msg->len += 8;
		return;
	}

	msg->ack++;
	cn_netlink_send(msg, 0, GFP_KERNEL);

	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
	hdr->len = sizeof(struct w1_netlink_cmd);
	cmd->len = 0;
}

static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
		unsigned int avail)
{
	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
	int search_type = (cmd->cmd == W1_CMD_ALARM_SEARCH)?W1_ALARM_SEARCH:W1_SEARCH;

	dev->priv = msg;
	dev->priv_size = avail;

	w1_search_devices(dev, search_type, w1_send_slave);

	msg->ack = 0;
	cn_netlink_send(msg, 0, GFP_KERNEL);

	dev->priv = NULL;
	dev->priv_size = 0;

	return 0;
}

static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_msg,
		struct w1_netlink_msg *req_hdr, struct w1_netlink_cmd *req_cmd)
{
	int err = -EINVAL;
	struct cn_msg *msg;
	struct w1_netlink_msg *hdr;
	struct w1_netlink_cmd *cmd;

	msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	msg->id = req_msg->id;
	msg->seq = req_msg->seq;
	msg->ack = 0;
	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);

	hdr = (struct w1_netlink_msg *)(msg + 1);
	cmd = (struct w1_netlink_cmd *)(hdr + 1);

	hdr->type = W1_MASTER_CMD;
	hdr->id = req_hdr->id;
	hdr->len = sizeof(struct w1_netlink_cmd);

	cmd->cmd = req_cmd->cmd;
	cmd->len = 0;

	switch (cmd->cmd) {
		case W1_CMD_SEARCH:
		case W1_CMD_ALARM_SEARCH:
			err = w1_process_search_command(dev, msg,
				PAGE_SIZE - msg->len - sizeof(struct cn_msg));
			break;
		default:
			cmd->res = EINVAL;
			cn_netlink_send(msg, 0, GFP_KERNEL);
			break;
	}

	kfree(msg);
	return err;
}

static int w1_send_read_reply(struct w1_slave *sl, struct cn_msg *msg,
		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
	void *data;
	struct w1_netlink_msg *h;
	struct w1_netlink_cmd *c;
	struct cn_msg *cm;
	int err;

	data = kzalloc(sizeof(struct cn_msg) +
			sizeof(struct w1_netlink_msg) +
			sizeof(struct w1_netlink_cmd) +
			cmd->len, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	cm = (struct cn_msg *)(data);
	h = (struct w1_netlink_msg *)(cm + 1);
	c = (struct w1_netlink_cmd *)(h + 1);

	memcpy(cm, msg, sizeof(struct cn_msg));
	memcpy(h, hdr, sizeof(struct w1_netlink_msg));
	memcpy(c, cmd, sizeof(struct w1_netlink_cmd));

	cm->ack = msg->seq+1;
	cm->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd) + cmd->len;

	h->len = sizeof(struct w1_netlink_cmd) + cmd->len;

	memcpy(c->data, cmd->data, c->len);

	err = cn_netlink_send(cm, 0, GFP_KERNEL);

	kfree(data);

	return err;
}

static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
	int err = 0;

	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);

	switch (cmd->cmd) {
		case W1_CMD_TOUCH:
			w1_touch_block(sl->master, cmd->data, cmd->len);
			w1_send_read_reply(sl, msg, hdr, cmd);
			break;
		case W1_CMD_READ:
			w1_read_block(sl->master, cmd->data, cmd->len);
			w1_send_read_reply(sl, msg, hdr, cmd);
			break;
		case W1_CMD_WRITE:
			w1_write_block(sl->master, cmd->data, cmd->len);
			break;
		default:
			err = -1;
			break;
	}

	return err;
}

static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mcmd)
{
	struct w1_master *m;
	struct cn_msg *cn;
	struct w1_netlink_msg *w;
	u32 *id;

	if (mcmd->type != W1_LIST_MASTERS) {
		printk(KERN_NOTICE "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
				__func__, msg->id.idx, msg->id.val, mcmd->type, mcmd->len);
		return -EPROTO;
	}

	cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!cn)
		return -ENOMEM;

	cn->id.idx = CN_W1_IDX;
	cn->id.val = CN_W1_VAL;

	cn->seq = msg->seq;
	cn->ack = 1;
	cn->len = sizeof(struct w1_netlink_msg);
	w = (struct w1_netlink_msg *)(cn + 1);

	w->type = W1_LIST_MASTERS;
	w->reserved = 0;
	w->len = 0;
	id = (u32 *)(w + 1);

	mutex_lock(&w1_mlock);
	list_for_each_entry(m, &w1_masters, w1_master_entry) {
		if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
			cn_netlink_send(cn, 0, GFP_KERNEL);
			cn->ack++;
			cn->len = sizeof(struct w1_netlink_msg);
			w->len = 0;
			id = (u32 *)(w + 1);
		}

		*id = m->id;
		w->len += sizeof(*id);
		cn->len += sizeof(*id);
		id++;
	}
	cn->ack = 0;
	cn_netlink_send(cn, 0, GFP_KERNEL);
	mutex_unlock(&w1_mlock);

	kfree(cn);
	return 0;
}

static void w1_cn_callback(void *data)
{
	struct cn_msg *msg = data;
	struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
	struct w1_netlink_cmd *cmd;
	struct w1_slave *sl;
	struct w1_master *dev;
	int err = 0;

	while (msg->len && !err) {
		struct w1_reg_num id;
		u16 mlen = m->len;
		u8 *cmd_data = m->data;

		dev = NULL;
		sl = NULL;

		memcpy(&id, m->id.id, sizeof(id));
#if 0
		printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
				__func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
#endif
		if (m->len + sizeof(struct w1_netlink_msg) > msg->len) {
			err = -E2BIG;
			break;
		}

		if (m->type == W1_MASTER_CMD) {
			dev = w1_search_master_id(m->id.mst.id);
		} else if (m->type == W1_SLAVE_CMD) {
			sl = w1_search_slave(&id);
			if (sl)
				dev = sl->master;
		} else {
			err = w1_process_command_root(msg, m);
			goto out_cont;
		}

		if (!dev) {
			err = -ENODEV;
			goto out_cont;
		}

		err = 0;
		if (!mlen)
			goto out_cont;

		mutex_lock(&dev->mutex);

		if (sl && w1_reset_select_slave(sl)) {
			err = -ENODEV;
			goto out_up;
		}

		while (mlen) {
			cmd = (struct w1_netlink_cmd *)cmd_data;

			if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
				err = -E2BIG;
				break;
			}

			if (sl)
				w1_process_command_slave(sl, msg, m, cmd);
			else
				w1_process_command_master(dev, msg, m, cmd);

			cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
			mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
		}
out_up:
		atomic_dec(&dev->refcnt);
		if (sl)
			atomic_dec(&sl->refcnt);
		mutex_unlock(&dev->mutex);
out_cont:
		msg->len -= sizeof(struct w1_netlink_msg) + m->len;
		m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);

		/*
		 * Let's allow requests for nonexisting devices.
		 */
		if (err == -ENODEV)
			err = 0;
	}
}

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 *msg)
{
}

int w1_init_netlink(void)
{
	return 0;
}

void w1_fini_netlink(void)
{
}
#endif