/* Copyright (C) 2010-2016  B.A.T.M.A.N. contributors:
 *
 * Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License 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, see <http://www.gnu.org/licenses/>.
 */

#include "debugfs.h"
#include "main.h"

#include <linux/compiler.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/printk.h>
#include <linux/sched.h> /* for linux/wait.h */
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <stdarg.h>

#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "gateway_client.h"
#include "icmp_socket.h"
#include "network-coding.h"
#include "originator.h"
#include "translation-table.h"

static struct dentry *batadv_debugfs;

#ifdef CONFIG_BATMAN_ADV_DEBUG
#define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)

static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN;

static char *batadv_log_char_addr(struct batadv_priv_debug_log *debug_log,
				  size_t idx)
{
	return &debug_log->log_buff[idx & BATADV_LOG_BUFF_MASK];
}

static void batadv_emit_log_char(struct batadv_priv_debug_log *debug_log,
				 char c)
{
	char *char_addr;

	char_addr = batadv_log_char_addr(debug_log, debug_log->log_end);
	*char_addr = c;
	debug_log->log_end++;

	if (debug_log->log_end - debug_log->log_start > batadv_log_buff_len)
		debug_log->log_start = debug_log->log_end - batadv_log_buff_len;
}

__printf(2, 3)
static int batadv_fdebug_log(struct batadv_priv_debug_log *debug_log,
			     const char *fmt, ...)
{
	va_list args;
	static char debug_log_buf[256];
	char *p;

	if (!debug_log)
		return 0;

	spin_lock_bh(&debug_log->lock);
	va_start(args, fmt);
	vscnprintf(debug_log_buf, sizeof(debug_log_buf), fmt, args);
	va_end(args);

	for (p = debug_log_buf; *p != 0; p++)
		batadv_emit_log_char(debug_log, *p);

	spin_unlock_bh(&debug_log->lock);

	wake_up(&debug_log->queue_wait);

	return 0;
}

int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
{
	va_list args;
	char tmp_log_buf[256];

	va_start(args, fmt);
	vscnprintf(tmp_log_buf, sizeof(tmp_log_buf), fmt, args);
	batadv_fdebug_log(bat_priv->debug_log, "[%10u] %s",
			  jiffies_to_msecs(jiffies), tmp_log_buf);
	va_end(args);

	return 0;
}

static int batadv_log_open(struct inode *inode, struct file *file)
{
	if (!try_module_get(THIS_MODULE))
		return -EBUSY;

	nonseekable_open(inode, file);
	file->private_data = inode->i_private;
	return 0;
}

static int batadv_log_release(struct inode *inode, struct file *file)
{
	module_put(THIS_MODULE);
	return 0;
}

static bool batadv_log_empty(struct batadv_priv_debug_log *debug_log)
{
	return !(debug_log->log_start - debug_log->log_end);
}

static ssize_t batadv_log_read(struct file *file, char __user *buf,
			       size_t count, loff_t *ppos)
{
	struct batadv_priv *bat_priv = file->private_data;
	struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;
	int error, i = 0;
	char *char_addr;
	char c;

	if ((file->f_flags & O_NONBLOCK) && batadv_log_empty(debug_log))
		return -EAGAIN;

	if (!buf)
		return -EINVAL;

	if (count == 0)
		return 0;

	if (!access_ok(VERIFY_WRITE, buf, count))
		return -EFAULT;

	error = wait_event_interruptible(debug_log->queue_wait,
					 (!batadv_log_empty(debug_log)));

	if (error)
		return error;

	spin_lock_bh(&debug_log->lock);

	while ((!error) && (i < count) &&
	       (debug_log->log_start != debug_log->log_end)) {
		char_addr = batadv_log_char_addr(debug_log,
						 debug_log->log_start);
		c = *char_addr;

		debug_log->log_start++;

		spin_unlock_bh(&debug_log->lock);

		error = __put_user(c, buf);

		spin_lock_bh(&debug_log->lock);

		buf++;
		i++;
	}

	spin_unlock_bh(&debug_log->lock);

	if (!error)
		return i;

	return error;
}

static unsigned int batadv_log_poll(struct file *file, poll_table *wait)
{
	struct batadv_priv *bat_priv = file->private_data;
	struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;

	poll_wait(file, &debug_log->queue_wait, wait);

	if (!batadv_log_empty(debug_log))
		return POLLIN | POLLRDNORM;

	return 0;
}

static const struct file_operations batadv_log_fops = {
	.open           = batadv_log_open,
	.release        = batadv_log_release,
	.read           = batadv_log_read,
	.poll           = batadv_log_poll,
	.llseek         = no_llseek,
};

static int batadv_debug_log_setup(struct batadv_priv *bat_priv)
{
	struct dentry *d;

	if (!bat_priv->debug_dir)
		goto err;

	bat_priv->debug_log = kzalloc(sizeof(*bat_priv->debug_log), GFP_ATOMIC);
	if (!bat_priv->debug_log)
		goto err;

	spin_lock_init(&bat_priv->debug_log->lock);
	init_waitqueue_head(&bat_priv->debug_log->queue_wait);

	d = debugfs_create_file("log", S_IFREG | S_IRUSR,
				bat_priv->debug_dir, bat_priv,
				&batadv_log_fops);
	if (!d)
		goto err;

	return 0;

err:
	return -ENOMEM;
}

static void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
{
	kfree(bat_priv->debug_log);
	bat_priv->debug_log = NULL;
}
#else /* CONFIG_BATMAN_ADV_DEBUG */
static int batadv_debug_log_setup(struct batadv_priv *bat_priv)
{
	return 0;
}

static void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
{
}
#endif

static int batadv_algorithms_open(struct inode *inode, struct file *file)
{
	return single_open(file, batadv_algo_seq_print_text, NULL);
}

static int neighbors_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_hardif_neigh_seq_print_text, net_dev);
}

static int batadv_originators_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_orig_seq_print_text, net_dev);
}

/**
 * batadv_originators_hardif_open - handles debugfs output for the
 *  originator table of an hard interface
 * @inode: inode pointer to debugfs file
 * @file: pointer to the seq_file
 *
 * Return: 0 on success or negative error number in case of failure
 */
static int batadv_originators_hardif_open(struct inode *inode,
					  struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_orig_hardif_seq_print_text, net_dev);
}

static int batadv_gateways_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_gw_client_seq_print_text, net_dev);
}

static int batadv_transtable_global_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_tt_global_seq_print_text, net_dev);
}

#ifdef CONFIG_BATMAN_ADV_BLA
static int batadv_bla_claim_table_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_bla_claim_table_seq_print_text,
			   net_dev);
}

static int batadv_bla_backbone_table_open(struct inode *inode,
					  struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_bla_backbone_table_seq_print_text,
			   net_dev);
}

#endif

#ifdef CONFIG_BATMAN_ADV_DAT
/**
 * batadv_dat_cache_open - Prepare file handler for reads from dat_chache
 * @inode: inode which was opened
 * @file: file handle to be initialized
 *
 * Return: 0 on success or negative error number in case of failure
 */
static int batadv_dat_cache_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_dat_cache_seq_print_text, net_dev);
}
#endif

static int batadv_transtable_local_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_tt_local_seq_print_text, net_dev);
}

struct batadv_debuginfo {
	struct attribute attr;
	const struct file_operations fops;
};

#ifdef CONFIG_BATMAN_ADV_NC
static int batadv_nc_nodes_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;

	return single_open(file, batadv_nc_nodes_seq_print_text, net_dev);
}
#endif

#define BATADV_DEBUGINFO(_name, _mode, _open)		\
struct batadv_debuginfo batadv_debuginfo_##_name = {	\
	.attr = {					\
		.name = __stringify(_name),		\
		.mode = _mode,				\
	},						\
	.fops = {					\
		.owner = THIS_MODULE,			\
		.open = _open,				\
		.read	= seq_read,			\
		.llseek = seq_lseek,			\
		.release = single_release,		\
	},						\
}

/* the following attributes are general and therefore they will be directly
 * placed in the BATADV_DEBUGFS_SUBDIR subdirectory of debugfs
 */
static BATADV_DEBUGINFO(routing_algos, S_IRUGO, batadv_algorithms_open);

static struct batadv_debuginfo *batadv_general_debuginfos[] = {
	&batadv_debuginfo_routing_algos,
	NULL,
};

/* The following attributes are per soft interface */
static BATADV_DEBUGINFO(neighbors, S_IRUGO, neighbors_open);
static BATADV_DEBUGINFO(originators, S_IRUGO, batadv_originators_open);
static BATADV_DEBUGINFO(gateways, S_IRUGO, batadv_gateways_open);
static BATADV_DEBUGINFO(transtable_global, S_IRUGO,
			batadv_transtable_global_open);
#ifdef CONFIG_BATMAN_ADV_BLA
static BATADV_DEBUGINFO(bla_claim_table, S_IRUGO, batadv_bla_claim_table_open);
static BATADV_DEBUGINFO(bla_backbone_table, S_IRUGO,
			batadv_bla_backbone_table_open);
#endif
#ifdef CONFIG_BATMAN_ADV_DAT
static BATADV_DEBUGINFO(dat_cache, S_IRUGO, batadv_dat_cache_open);
#endif
static BATADV_DEBUGINFO(transtable_local, S_IRUGO,
			batadv_transtable_local_open);
#ifdef CONFIG_BATMAN_ADV_NC
static BATADV_DEBUGINFO(nc_nodes, S_IRUGO, batadv_nc_nodes_open);
#endif

static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
	&batadv_debuginfo_neighbors,
	&batadv_debuginfo_originators,
	&batadv_debuginfo_gateways,
	&batadv_debuginfo_transtable_global,
#ifdef CONFIG_BATMAN_ADV_BLA
	&batadv_debuginfo_bla_claim_table,
	&batadv_debuginfo_bla_backbone_table,
#endif
#ifdef CONFIG_BATMAN_ADV_DAT
	&batadv_debuginfo_dat_cache,
#endif
	&batadv_debuginfo_transtable_local,
#ifdef CONFIG_BATMAN_ADV_NC
	&batadv_debuginfo_nc_nodes,
#endif
	NULL,
};

#define BATADV_HARDIF_DEBUGINFO(_name, _mode, _open)		\
struct batadv_debuginfo batadv_hardif_debuginfo_##_name = {	\
	.attr = {						\
		.name = __stringify(_name),			\
		.mode = _mode,					\
	},							\
	.fops = {						\
		.owner = THIS_MODULE,				\
		.open = _open,					\
		.read	= seq_read,				\
		.llseek = seq_lseek,				\
		.release = single_release,			\
	},							\
}

static BATADV_HARDIF_DEBUGINFO(originators, S_IRUGO,
			       batadv_originators_hardif_open);

static struct batadv_debuginfo *batadv_hardif_debuginfos[] = {
	&batadv_hardif_debuginfo_originators,
	NULL,
};

void batadv_debugfs_init(void)
{
	struct batadv_debuginfo **bat_debug;
	struct dentry *file;

	batadv_debugfs = debugfs_create_dir(BATADV_DEBUGFS_SUBDIR, NULL);
	if (batadv_debugfs == ERR_PTR(-ENODEV))
		batadv_debugfs = NULL;

	if (!batadv_debugfs)
		goto err;

	for (bat_debug = batadv_general_debuginfos; *bat_debug; ++bat_debug) {
		file = debugfs_create_file(((*bat_debug)->attr).name,
					   S_IFREG | ((*bat_debug)->attr).mode,
					   batadv_debugfs, NULL,
					   &(*bat_debug)->fops);
		if (!file) {
			pr_err("Can't add general debugfs file: %s\n",
			       ((*bat_debug)->attr).name);
			goto err;
		}
	}

	return;
err:
	debugfs_remove_recursive(batadv_debugfs);
	batadv_debugfs = NULL;
}

void batadv_debugfs_destroy(void)
{
	debugfs_remove_recursive(batadv_debugfs);
	batadv_debugfs = NULL;
}

/**
 * batadv_debugfs_add_hardif - creates the base directory for a hard interface
 *  in debugfs.
 * @hard_iface: hard interface which should be added.
 *
 * Return: 0 on success or negative error number in case of failure
 */
int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
{
	struct batadv_debuginfo **bat_debug;
	struct dentry *file;

	if (!batadv_debugfs)
		goto out;

	hard_iface->debug_dir = debugfs_create_dir(hard_iface->net_dev->name,
						   batadv_debugfs);
	if (!hard_iface->debug_dir)
		goto out;

	for (bat_debug = batadv_hardif_debuginfos; *bat_debug; ++bat_debug) {
		file = debugfs_create_file(((*bat_debug)->attr).name,
					   S_IFREG | ((*bat_debug)->attr).mode,
					   hard_iface->debug_dir,
					   hard_iface->net_dev,
					   &(*bat_debug)->fops);
		if (!file)
			goto rem_attr;
	}

	return 0;
rem_attr:
	debugfs_remove_recursive(hard_iface->debug_dir);
	hard_iface->debug_dir = NULL;
out:
	return -ENOMEM;
}

/**
 * batadv_debugfs_del_hardif - delete the base directory for a hard interface
 *  in debugfs.
 * @hard_iface: hard interface which is deleted.
 */
void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface)
{
	if (batadv_debugfs) {
		debugfs_remove_recursive(hard_iface->debug_dir);
		hard_iface->debug_dir = NULL;
	}
}

int batadv_debugfs_add_meshif(struct net_device *dev)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	struct batadv_debuginfo **bat_debug;
	struct dentry *file;

	if (!batadv_debugfs)
		goto out;

	bat_priv->debug_dir = debugfs_create_dir(dev->name, batadv_debugfs);
	if (!bat_priv->debug_dir)
		goto out;

	if (batadv_socket_setup(bat_priv) < 0)
		goto rem_attr;

	if (batadv_debug_log_setup(bat_priv) < 0)
		goto rem_attr;

	for (bat_debug = batadv_mesh_debuginfos; *bat_debug; ++bat_debug) {
		file = debugfs_create_file(((*bat_debug)->attr).name,
					   S_IFREG | ((*bat_debug)->attr).mode,
					   bat_priv->debug_dir,
					   dev, &(*bat_debug)->fops);
		if (!file) {
			batadv_err(dev, "Can't add debugfs file: %s/%s\n",
				   dev->name, ((*bat_debug)->attr).name);
			goto rem_attr;
		}
	}

	if (batadv_nc_init_debugfs(bat_priv) < 0)
		goto rem_attr;

	return 0;
rem_attr:
	debugfs_remove_recursive(bat_priv->debug_dir);
	bat_priv->debug_dir = NULL;
out:
	return -ENOMEM;
}

void batadv_debugfs_del_meshif(struct net_device *dev)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);

	batadv_debug_log_cleanup(bat_priv);

	if (batadv_debugfs) {
		debugfs_remove_recursive(bat_priv->debug_dir);
		bat_priv->debug_dir = NULL;
	}
}