/* 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 int 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;
        }
}