/*
   * proc.c - procfs support for Protocol family CAN core module
   *
   * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of Volkswagen nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * Alternatively, provided that this notice is retained in full, this
   * software may be distributed under the terms of the GNU General
   * Public License ("GPL") version 2, in which case the provisions of the
   * GPL apply INSTEAD OF those given above.
   *
   * The provided data structures and external interfaces from this code
   * are not restricted to be used by modules with a GPL compatible license.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   */
  
  #include <linux/module.h>
  #include <linux/proc_fs.h>
  #include <linux/list.h>
  #include <linux/rcupdate.h>
  #include <linux/if_arp.h>
  #include <linux/can/core.h>
  
  #include "af_can.h"
  
  /*
   * proc filenames for the PF_CAN core
   */
  
  #define CAN_PROC_VERSION     "version"
  #define CAN_PROC_STATS       "stats"
  #define CAN_PROC_RESET_STATS "reset_stats"
  #define CAN_PROC_RCVLIST_ALL "rcvlist_all"
  #define CAN_PROC_RCVLIST_FIL "rcvlist_fil"
  #define CAN_PROC_RCVLIST_INV "rcvlist_inv"
  #define CAN_PROC_RCVLIST_SFF "rcvlist_sff"
  #define CAN_PROC_RCVLIST_EFF "rcvlist_eff"
  #define CAN_PROC_RCVLIST_ERR "rcvlist_err"
  
  static struct proc_dir_entry *can_dir;
  static struct proc_dir_entry *pde_version;
  static struct proc_dir_entry *pde_stats;
  static struct proc_dir_entry *pde_reset_stats;
  static struct proc_dir_entry *pde_rcvlist_all;
  static struct proc_dir_entry *pde_rcvlist_fil;
  static struct proc_dir_entry *pde_rcvlist_inv;
  static struct proc_dir_entry *pde_rcvlist_sff;
  static struct proc_dir_entry *pde_rcvlist_eff;
  static struct proc_dir_entry *pde_rcvlist_err;
  
  static int user_reset;
  
  static const char rx_list_name[][8] = {
  	[RX_ERR] = "rx_err",
  	[RX_ALL] = "rx_all",
  	[RX_FIL] = "rx_fil",
  	[RX_INV] = "rx_inv",
  	[RX_EFF] = "rx_eff",
  };
  
  /*
   * af_can statistics stuff
   */
  
  static void can_init_stats(void)
  {
  	/*
  	 * This memset function is called from a timer context (when
  	 * can_stattimer is active which is the default) OR in a process
  	 * context (reading the proc_fs when can_stattimer is disabled).
  	 */
  	memset(&can_stats, 0, sizeof(can_stats));
  	can_stats.jiffies_init = jiffies;
  
  	can_pstats.stats_reset++;
  
  	if (user_reset) {
  		user_reset = 0;
  		can_pstats.user_reset++;
  	}
  }
  
  static unsigned long calc_rate(unsigned long oldjif, unsigned long newjif,
  			       unsigned long count)
  {
  	unsigned long rate;
  
  	if (oldjif == newjif)
  		return 0;
  
  	/* see can_stat_update() - this should NEVER happen! */
  	if (count > (ULONG_MAX / HZ)) {
  		printk(KERN_ERR "can: calc_rate: count exceeded! %ld
  ",
  		       count);
  		return 99999999;
  	}
  
  	rate = (count * HZ) / (newjif - oldjif);
  
  	return rate;
  }
  
  void can_stat_update(unsigned long data)
  {
  	unsigned long j = jiffies; /* snapshot */
  
  	/* restart counting in timer context on user request */
  	if (user_reset)
  		can_init_stats();
  
  	/* restart counting on jiffies overflow */
  	if (j < can_stats.jiffies_init)
  		can_init_stats();
  
  	/* prevent overflow in calc_rate() */
  	if (can_stats.rx_frames > (ULONG_MAX / HZ))
  		can_init_stats();
  
  	/* prevent overflow in calc_rate() */
  	if (can_stats.tx_frames > (ULONG_MAX / HZ))
  		can_init_stats();
  
  	/* matches overflow - very improbable */
  	if (can_stats.matches > (ULONG_MAX / 100))
  		can_init_stats();
  
  	/* calc total values */
  	if (can_stats.rx_frames)
  		can_stats.total_rx_match_ratio = (can_stats.matches * 100) /
  			can_stats.rx_frames;
  
  	can_stats.total_tx_rate = calc_rate(can_stats.jiffies_init, j,
  					    can_stats.tx_frames);
  	can_stats.total_rx_rate = calc_rate(can_stats.jiffies_init, j,
  					    can_stats.rx_frames);
  
  	/* calc current values */
  	if (can_stats.rx_frames_delta)
  		can_stats.current_rx_match_ratio =
  			(can_stats.matches_delta * 100) /
  			can_stats.rx_frames_delta;
  
  	can_stats.current_tx_rate = calc_rate(0, HZ, can_stats.tx_frames_delta);
  	can_stats.current_rx_rate = calc_rate(0, HZ, can_stats.rx_frames_delta);
  
  	/* check / update maximum values */
  	if (can_stats.max_tx_rate < can_stats.current_tx_rate)
  		can_stats.max_tx_rate = can_stats.current_tx_rate;
  
  	if (can_stats.max_rx_rate < can_stats.current_rx_rate)
  		can_stats.max_rx_rate = can_stats.current_rx_rate;
  
  	if (can_stats.max_rx_match_ratio < can_stats.current_rx_match_ratio)
  		can_stats.max_rx_match_ratio = can_stats.current_rx_match_ratio;
  
  	/* clear values for 'current rate' calculation */
  	can_stats.tx_frames_delta = 0;
  	can_stats.rx_frames_delta = 0;
  	can_stats.matches_delta   = 0;
  
  	/* restart timer (one second) */
  	mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
  }
  
  /*
   * proc read functions
   */
  
  static void can_print_rcvlist(struct seq_file *m, struct hlist_head *rx_list,
  			      struct net_device *dev)
  {
  	struct receiver *r;
  
  	hlist_for_each_entry_rcu(r, rx_list, list) {
  		char *fmt = (r->can_id & CAN_EFF_FLAG)?
  			"   %-5s  %08x  %08x  %pK  %pK  %8ld  %s
  " :
  			"   %-5s     %03x    %08x  %pK  %pK  %8ld  %s
  ";
  
  		seq_printf(m, fmt, DNAME(dev), r->can_id, r->mask,
  				r->func, r->data, r->matches, r->ident);
  	}
  }
  
  static void can_print_recv_banner(struct seq_file *m)
  {
  	/*
  	 *                  can1.  00000000  00000000  00000000
  	 *                 .......          0  tp20
  	 */
  	seq_puts(m, "  device   can_id   can_mask  function"
  			"  userdata   matches  ident
  ");
  }
  
  static int can_stats_proc_show(struct seq_file *m, void *v)
  {
  	seq_putc(m, '
  ');
  	seq_printf(m, " %8ld transmitted frames (TXF)
  ", can_stats.tx_frames);
  	seq_printf(m, " %8ld received frames (RXF)
  ", can_stats.rx_frames);
  	seq_printf(m, " %8ld matched frames (RXMF)
  ", can_stats.matches);
  
  	seq_putc(m, '
  ');
  
  	if (can_stattimer.function == can_stat_update) {
  		seq_printf(m, " %8ld %% total match ratio (RXMR)
  ",
  				can_stats.total_rx_match_ratio);
  
  		seq_printf(m, " %8ld frames/s total tx rate (TXR)
  ",
  				can_stats.total_tx_rate);
  		seq_printf(m, " %8ld frames/s total rx rate (RXR)
  ",
  				can_stats.total_rx_rate);
  
  		seq_putc(m, '
  ');
  
  		seq_printf(m, " %8ld %% current match ratio (CRXMR)
  ",
  				can_stats.current_rx_match_ratio);
  
  		seq_printf(m, " %8ld frames/s current tx rate (CTXR)
  ",
  				can_stats.current_tx_rate);
  		seq_printf(m, " %8ld frames/s current rx rate (CRXR)
  ",
  				can_stats.current_rx_rate);
  
  		seq_putc(m, '
  ');
  
  		seq_printf(m, " %8ld %% max match ratio (MRXMR)
  ",
  				can_stats.max_rx_match_ratio);
  
  		seq_printf(m, " %8ld frames/s max tx rate (MTXR)
  ",
  				can_stats.max_tx_rate);
  		seq_printf(m, " %8ld frames/s max rx rate (MRXR)
  ",
  				can_stats.max_rx_rate);
  
  		seq_putc(m, '
  ');
  	}
  
  	seq_printf(m, " %8ld current receive list entries (CRCV)
  ",
  			can_pstats.rcv_entries);
  	seq_printf(m, " %8ld maximum receive list entries (MRCV)
  ",
  			can_pstats.rcv_entries_max);
  
  	if (can_pstats.stats_reset)
  		seq_printf(m, "
   %8ld statistic resets (STR)
  ",
  				can_pstats.stats_reset);
  
  	if (can_pstats.user_reset)
  		seq_printf(m, " %8ld user statistic resets (USTR)
  ",
  				can_pstats.user_reset);
  
  	seq_putc(m, '
  ');
  	return 0;
  }
  
  static int can_stats_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, can_stats_proc_show, NULL);
  }
  
  static const struct file_operations can_stats_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= can_stats_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static int can_reset_stats_proc_show(struct seq_file *m, void *v)
  {
  	user_reset = 1;
  
  	if (can_stattimer.function == can_stat_update) {
  		seq_printf(m, "Scheduled statistic reset #%ld.
  ",
  				can_pstats.stats_reset + 1);
  
  	} else {
  		if (can_stats.jiffies_init != jiffies)
  			can_init_stats();
  
  		seq_printf(m, "Performed statistic reset #%ld.
  ",
  				can_pstats.stats_reset);
  	}
  	return 0;
  }
  
  static int can_reset_stats_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, can_reset_stats_proc_show, NULL);
  }
  
  static const struct file_operations can_reset_stats_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= can_reset_stats_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static int can_version_proc_show(struct seq_file *m, void *v)
  {
  	seq_printf(m, "%s
  ", CAN_VERSION_STRING);
  	return 0;
  }
  
  static int can_version_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, can_version_proc_show, NULL);
  }
  
  static const struct file_operations can_version_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= can_version_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static inline void can_rcvlist_proc_show_one(struct seq_file *m, int idx,
  					     struct net_device *dev,
  					     struct dev_rcv_lists *d)
  {
  	if (!hlist_empty(&d->rx[idx])) {
  		can_print_recv_banner(m);
  		can_print_rcvlist(m, &d->rx[idx], dev);
  	} else
  		seq_printf(m, "  (%s: no entry)
  ", DNAME(dev));
  
  }
  
  static int can_rcvlist_proc_show(struct seq_file *m, void *v)
  {
  	/* double cast to prevent GCC warning */
  	int idx = (int)(long)m->private;
  	struct net_device *dev;
  	struct dev_rcv_lists *d;
  
  	seq_printf(m, "
  receive list '%s':
  ", rx_list_name[idx]);
  
  	rcu_read_lock();
  
  	/* receive list for 'all' CAN devices (dev == NULL) */
  	d = &can_rx_alldev_list;
  	can_rcvlist_proc_show_one(m, idx, NULL, d);
  
  	/* receive list for registered CAN devices */
  	for_each_netdev_rcu(&init_net, dev) {
  		if (dev->type == ARPHRD_CAN && dev->ml_priv)
  			can_rcvlist_proc_show_one(m, idx, dev, dev->ml_priv);
  	}
  
  	rcu_read_unlock();
  
  	seq_putc(m, '
  ');
  	return 0;
  }
  
  static int can_rcvlist_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, can_rcvlist_proc_show, PDE_DATA(inode));
  }
  
  static const struct file_operations can_rcvlist_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= can_rcvlist_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static inline void can_rcvlist_sff_proc_show_one(struct seq_file *m,
  						 struct net_device *dev,
  						 struct dev_rcv_lists *d)
  {
  	int i;
  	int all_empty = 1;
  
  	/* check whether at least one list is non-empty */
  	for (i = 0; i < 0x800; i++)
  		if (!hlist_empty(&d->rx_sff[i])) {
  			all_empty = 0;
  			break;
  		}
  
  	if (!all_empty) {
  		can_print_recv_banner(m);
  		for (i = 0; i < 0x800; i++) {
  			if (!hlist_empty(&d->rx_sff[i]))
  				can_print_rcvlist(m, &d->rx_sff[i], dev);
  		}
  	} else
  		seq_printf(m, "  (%s: no entry)
  ", DNAME(dev));
  }
  
  static int can_rcvlist_sff_proc_show(struct seq_file *m, void *v)
  {
  	struct net_device *dev;
  	struct dev_rcv_lists *d;
  
  	/* RX_SFF */
  	seq_puts(m, "
  receive list 'rx_sff':
  ");
  
  	rcu_read_lock();
  
  	/* sff receive list for 'all' CAN devices (dev == NULL) */
  	d = &can_rx_alldev_list;
  	can_rcvlist_sff_proc_show_one(m, NULL, d);
  
  	/* sff receive list for registered CAN devices */
  	for_each_netdev_rcu(&init_net, dev) {
  		if (dev->type == ARPHRD_CAN && dev->ml_priv)
  			can_rcvlist_sff_proc_show_one(m, dev, dev->ml_priv);
  	}
  
  	rcu_read_unlock();
  
  	seq_putc(m, '
  ');
  	return 0;
  }
  
  static int can_rcvlist_sff_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, can_rcvlist_sff_proc_show, NULL);
  }
  
  static const struct file_operations can_rcvlist_sff_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= can_rcvlist_sff_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  /*
   * proc utility functions
   */
  
  static void can_remove_proc_readentry(const char *name)
  {
  	if (can_dir)
  		remove_proc_entry(name, can_dir);
  }
  
  /*
   * can_init_proc - create main CAN proc directory and procfs entries
   */
  void can_init_proc(void)
  {
  	/* create /proc/net/can directory */
  	can_dir = proc_mkdir("can", init_net.proc_net);
  
  	if (!can_dir) {
  		printk(KERN_INFO "can: failed to create /proc/net/can . "
  		       "CONFIG_PROC_FS missing?
  ");
  		return;
  	}
  
  	/* own procfs entries from the AF_CAN core */
  	pde_version     = proc_create(CAN_PROC_VERSION, 0644, can_dir,
  				      &can_version_proc_fops);
  	pde_stats       = proc_create(CAN_PROC_STATS, 0644, can_dir,
  				      &can_stats_proc_fops);
  	pde_reset_stats = proc_create(CAN_PROC_RESET_STATS, 0644, can_dir,
  				      &can_reset_stats_proc_fops);
  	pde_rcvlist_err = proc_create_data(CAN_PROC_RCVLIST_ERR, 0644, can_dir,
  					   &can_rcvlist_proc_fops, (void *)RX_ERR);
  	pde_rcvlist_all = proc_create_data(CAN_PROC_RCVLIST_ALL, 0644, can_dir,
  					   &can_rcvlist_proc_fops, (void *)RX_ALL);
  	pde_rcvlist_fil = proc_create_data(CAN_PROC_RCVLIST_FIL, 0644, can_dir,
  					   &can_rcvlist_proc_fops, (void *)RX_FIL);
  	pde_rcvlist_inv = proc_create_data(CAN_PROC_RCVLIST_INV, 0644, can_dir,
  					   &can_rcvlist_proc_fops, (void *)RX_INV);
  	pde_rcvlist_eff = proc_create_data(CAN_PROC_RCVLIST_EFF, 0644, can_dir,
  					   &can_rcvlist_proc_fops, (void *)RX_EFF);
  	pde_rcvlist_sff = proc_create(CAN_PROC_RCVLIST_SFF, 0644, can_dir,
  				      &can_rcvlist_sff_proc_fops);
  }
  
  /*
   * can_remove_proc - remove procfs entries and main CAN proc directory
   */
  void can_remove_proc(void)
  {
  	if (pde_version)
  		can_remove_proc_readentry(CAN_PROC_VERSION);
  
  	if (pde_stats)
  		can_remove_proc_readentry(CAN_PROC_STATS);
  
  	if (pde_reset_stats)
  		can_remove_proc_readentry(CAN_PROC_RESET_STATS);
  
  	if (pde_rcvlist_err)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_ERR);
  
  	if (pde_rcvlist_all)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_ALL);
  
  	if (pde_rcvlist_fil)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_FIL);
  
  	if (pde_rcvlist_inv)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_INV);
  
  	if (pde_rcvlist_eff)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_EFF);
  
  	if (pde_rcvlist_sff)
  		can_remove_proc_readentry(CAN_PROC_RCVLIST_SFF);
  
  	if (can_dir)
  		remove_proc_entry("can", init_net.proc_net);
  }