// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
/*
 * 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/can-ml.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 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",
};

/*
 * af_can statistics stuff
 */

static void can_init_stats(struct net *net)
{
        struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
        struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
        /*
         * 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(pkg_stats, 0, sizeof(struct can_pkg_stats));
        pkg_stats->jiffies_init = jiffies;

        rcv_lists_stats->stats_reset++;

        if (user_reset) {
                user_reset = 0;
                rcv_lists_stats->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\n",
                       count);
                return 99999999;
        }

        rate = (count * HZ) / (newjif - oldjif);

        return rate;
}

void can_stat_update(struct timer_list *t)
{
        struct net *net = from_timer(net, t, can.stattimer);
        struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
        unsigned long j = jiffies; /* snapshot */

        /* restart counting in timer context on user request */
        if (user_reset)
                can_init_stats(net);

        /* restart counting on jiffies overflow */
        if (j < pkg_stats->jiffies_init)
                can_init_stats(net);

        /* prevent overflow in calc_rate() */
        if (pkg_stats->rx_frames > (ULONG_MAX / HZ))
                can_init_stats(net);

        /* prevent overflow in calc_rate() */
        if (pkg_stats->tx_frames > (ULONG_MAX / HZ))
                can_init_stats(net);

        /* matches overflow - very improbable */
        if (pkg_stats->matches > (ULONG_MAX / 100))
                can_init_stats(net);

        /* calc total values */
        if (pkg_stats->rx_frames)
                pkg_stats->total_rx_match_ratio = (pkg_stats->matches * 100) /
                        pkg_stats->rx_frames;

        pkg_stats->total_tx_rate = calc_rate(pkg_stats->jiffies_init, j,
                                            pkg_stats->tx_frames);
        pkg_stats->total_rx_rate = calc_rate(pkg_stats->jiffies_init, j,
                                            pkg_stats->rx_frames);

        /* calc current values */
        if (pkg_stats->rx_frames_delta)
                pkg_stats->current_rx_match_ratio =
                        (pkg_stats->matches_delta * 100) /
                        pkg_stats->rx_frames_delta;

        pkg_stats->current_tx_rate = calc_rate(0, HZ, pkg_stats->tx_frames_delta);
        pkg_stats->current_rx_rate = calc_rate(0, HZ, pkg_stats->rx_frames_delta);

        /* check / update maximum values */
        if (pkg_stats->max_tx_rate < pkg_stats->current_tx_rate)
                pkg_stats->max_tx_rate = pkg_stats->current_tx_rate;

        if (pkg_stats->max_rx_rate < pkg_stats->current_rx_rate)
                pkg_stats->max_rx_rate = pkg_stats->current_rx_rate;

        if (pkg_stats->max_rx_match_ratio < pkg_stats->current_rx_match_ratio)
                pkg_stats->max_rx_match_ratio = pkg_stats->current_rx_match_ratio;

        /* clear values for 'current rate' calculation */
        pkg_stats->tx_frames_delta = 0;
        pkg_stats->rx_frames_delta = 0;
        pkg_stats->matches_delta   = 0;

        /* restart timer (one second) */
        mod_timer(&net->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\n" :
                        "   %-5s     %03x    %08x  %pK  %pK  %8ld  %s\n";

                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\n");
}

static int can_stats_proc_show(struct seq_file *m, void *v)
{
        struct net *net = m->private;
        struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
        struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;

        seq_putc(m, '\n');
        seq_printf(m, " %8ld transmitted frames (TXF)\n", pkg_stats->tx_frames);
        seq_printf(m, " %8ld received frames (RXF)\n", pkg_stats->rx_frames);
        seq_printf(m, " %8ld matched frames (RXMF)\n", pkg_stats->matches);

        seq_putc(m, '\n');

        if (net->can.stattimer.function == can_stat_update) {
                seq_printf(m, " %8ld %% total match ratio (RXMR)\n",
                                pkg_stats->total_rx_match_ratio);

                seq_printf(m, " %8ld frames/s total tx rate (TXR)\n",
                                pkg_stats->total_tx_rate);
                seq_printf(m, " %8ld frames/s total rx rate (RXR)\n",
                                pkg_stats->total_rx_rate);

                seq_putc(m, '\n');

                seq_printf(m, " %8ld %% current match ratio (CRXMR)\n",
                                pkg_stats->current_rx_match_ratio);

                seq_printf(m, " %8ld frames/s current tx rate (CTXR)\n",
                                pkg_stats->current_tx_rate);
                seq_printf(m, " %8ld frames/s current rx rate (CRXR)\n",
                                pkg_stats->current_rx_rate);

                seq_putc(m, '\n');

                seq_printf(m, " %8ld %% max match ratio (MRXMR)\n",
                                pkg_stats->max_rx_match_ratio);

                seq_printf(m, " %8ld frames/s max tx rate (MTXR)\n",
                                pkg_stats->max_tx_rate);
                seq_printf(m, " %8ld frames/s max rx rate (MRXR)\n",
                                pkg_stats->max_rx_rate);

                seq_putc(m, '\n');
        }

        seq_printf(m, " %8ld current receive list entries (CRCV)\n",
                        rcv_lists_stats->rcv_entries);
        seq_printf(m, " %8ld maximum receive list entries (MRCV)\n",
                        rcv_lists_stats->rcv_entries_max);

        if (rcv_lists_stats->stats_reset)
                seq_printf(m, "\n %8ld statistic resets (STR)\n",
                                rcv_lists_stats->stats_reset);

        if (rcv_lists_stats->user_reset)
                seq_printf(m, " %8ld user statistic resets (USTR)\n",
                                rcv_lists_stats->user_reset);

        seq_putc(m, '\n');
        return 0;
}

static int can_reset_stats_proc_show(struct seq_file *m, void *v)
{
        struct net *net = m->private;
        struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
        struct can_pkg_stats *pkg_stats = net->can.pkg_stats;

        user_reset = 1;

        if (net->can.stattimer.function == can_stat_update) {
                seq_printf(m, "Scheduled statistic reset #%ld.\n",
                                rcv_lists_stats->stats_reset + 1);
        } else {
                if (pkg_stats->jiffies_init != jiffies)
                        can_init_stats(net);

                seq_printf(m, "Performed statistic reset #%ld.\n",
                                rcv_lists_stats->stats_reset);
        }
        return 0;
}

static int can_version_proc_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%s\n", CAN_VERSION_STRING);
        return 0;
}

static inline void can_rcvlist_proc_show_one(struct seq_file *m, int idx,
                                             struct net_device *dev,
                                             struct can_dev_rcv_lists *dev_rcv_lists)
{
        if (!hlist_empty(&dev_rcv_lists->rx[idx])) {
                can_print_recv_banner(m);
                can_print_rcvlist(m, &dev_rcv_lists->rx[idx], dev);
        } else
                seq_printf(m, "  (%s: no entry)\n", DNAME(dev));

}

static int can_rcvlist_proc_show(struct seq_file *m, void *v)
{
        /* double cast to prevent GCC warning */
        int idx = (int)(long)PDE_DATA(m->file->f_inode);
        struct net_device *dev;
        struct can_dev_rcv_lists *dev_rcv_lists;
        struct net *net = m->private;

        seq_printf(m, "\nreceive list '%s':\n", rx_list_name[idx]);

        rcu_read_lock();

        /* receive list for 'all' CAN devices (dev == NULL) */
        dev_rcv_lists = net->can.rx_alldev_list;
        can_rcvlist_proc_show_one(m, idx, NULL, dev_rcv_lists);

        /* receive list for registered CAN devices */
        for_each_netdev_rcu(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, '\n');
        return 0;
}

static inline void can_rcvlist_proc_show_array(struct seq_file *m,
                                               struct net_device *dev,
                                               struct hlist_head *rcv_array,
                                               unsigned int rcv_array_sz)
{
        unsigned int i;
        int all_empty = 1;

        /* check whether at least one list is non-empty */
        for (i = 0; i < rcv_array_sz; i++)
                if (!hlist_empty(&rcv_array[i])) {
                        all_empty = 0;
                        break;
                }

        if (!all_empty) {
                can_print_recv_banner(m);
                for (i = 0; i < rcv_array_sz; i++) {
                        if (!hlist_empty(&rcv_array[i]))
                                can_print_rcvlist(m, &rcv_array[i], dev);
                }
        } else
                seq_printf(m, "  (%s: no entry)\n", DNAME(dev));
}

static int can_rcvlist_sff_proc_show(struct seq_file *m, void *v)
{
        struct net_device *dev;
        struct can_dev_rcv_lists *dev_rcv_lists;
        struct net *net = m->private;

        /* RX_SFF */
        seq_puts(m, "\nreceive list 'rx_sff':\n");

        rcu_read_lock();

        /* sff receive list for 'all' CAN devices (dev == NULL) */
        dev_rcv_lists = net->can.rx_alldev_list;
        can_rcvlist_proc_show_array(m, NULL, dev_rcv_lists->rx_sff,
                                    ARRAY_SIZE(dev_rcv_lists->rx_sff));

        /* sff receive list for registered CAN devices */
        for_each_netdev_rcu(net, dev) {
                if (dev->type == ARPHRD_CAN && dev->ml_priv) {
                        dev_rcv_lists = dev->ml_priv;
                        can_rcvlist_proc_show_array(m, dev, dev_rcv_lists->rx_sff,
                                                    ARRAY_SIZE(dev_rcv_lists->rx_sff));
                }
        }

        rcu_read_unlock();

        seq_putc(m, '\n');
        return 0;
}

static int can_rcvlist_eff_proc_show(struct seq_file *m, void *v)
{
        struct net_device *dev;
        struct can_dev_rcv_lists *dev_rcv_lists;
        struct net *net = m->private;

        /* RX_EFF */
        seq_puts(m, "\nreceive list 'rx_eff':\n");

        rcu_read_lock();

        /* eff receive list for 'all' CAN devices (dev == NULL) */
        dev_rcv_lists = net->can.rx_alldev_list;
        can_rcvlist_proc_show_array(m, NULL, dev_rcv_lists->rx_eff,
                                    ARRAY_SIZE(dev_rcv_lists->rx_eff));

        /* eff receive list for registered CAN devices */
        for_each_netdev_rcu(net, dev) {
                if (dev->type == ARPHRD_CAN && dev->ml_priv) {
                        dev_rcv_lists = dev->ml_priv;
                        can_rcvlist_proc_show_array(m, dev, dev_rcv_lists->rx_eff,
                                                    ARRAY_SIZE(dev_rcv_lists->rx_eff));
                }
        }

        rcu_read_unlock();

        seq_putc(m, '\n');
        return 0;
}

/*
 * can_init_proc - create main CAN proc directory and procfs entries
 */
void can_init_proc(struct net *net)
{
        /* create /proc/net/can directory */
        net->can.proc_dir = proc_net_mkdir(net, "can", net->proc_net);

        if (!net->can.proc_dir) {
                printk(KERN_INFO "can: failed to create /proc/net/can . "
                           "CONFIG_PROC_FS missing?\n");
                return;
        }

        /* own procfs entries from the AF_CAN core */
        net->can.pde_version = proc_create_net_single(CAN_PROC_VERSION, 0644,
                        net->can.proc_dir, can_version_proc_show, NULL);
        net->can.pde_stats = proc_create_net_single(CAN_PROC_STATS, 0644,
                        net->can.proc_dir, can_stats_proc_show, NULL);
        net->can.pde_reset_stats = proc_create_net_single(CAN_PROC_RESET_STATS,
                        0644, net->can.proc_dir, can_reset_stats_proc_show,
                        NULL);
        net->can.pde_rcvlist_err = proc_create_net_single(CAN_PROC_RCVLIST_ERR,
                        0644, net->can.proc_dir, can_rcvlist_proc_show,
                        (void *)RX_ERR);
        net->can.pde_rcvlist_all = proc_create_net_single(CAN_PROC_RCVLIST_ALL,
                        0644, net->can.proc_dir, can_rcvlist_proc_show,
                        (void *)RX_ALL);
        net->can.pde_rcvlist_fil = proc_create_net_single(CAN_PROC_RCVLIST_FIL,
                        0644, net->can.proc_dir, can_rcvlist_proc_show,
                        (void *)RX_FIL);
        net->can.pde_rcvlist_inv = proc_create_net_single(CAN_PROC_RCVLIST_INV,
                        0644, net->can.proc_dir, can_rcvlist_proc_show,
                        (void *)RX_INV);
        net->can.pde_rcvlist_eff = proc_create_net_single(CAN_PROC_RCVLIST_EFF,
                        0644, net->can.proc_dir, can_rcvlist_eff_proc_show, NULL);
        net->can.pde_rcvlist_sff = proc_create_net_single(CAN_PROC_RCVLIST_SFF,
                        0644, net->can.proc_dir, can_rcvlist_sff_proc_show, NULL);
}

/*
 * can_remove_proc - remove procfs entries and main CAN proc directory
 */
void can_remove_proc(struct net *net)
{
        if (net->can.pde_version)
                remove_proc_entry(CAN_PROC_VERSION, net->can.proc_dir);

        if (net->can.pde_stats)
                remove_proc_entry(CAN_PROC_STATS, net->can.proc_dir);

        if (net->can.pde_reset_stats)
                remove_proc_entry(CAN_PROC_RESET_STATS, net->can.proc_dir);

        if (net->can.pde_rcvlist_err)
                remove_proc_entry(CAN_PROC_RCVLIST_ERR, net->can.proc_dir);

        if (net->can.pde_rcvlist_all)
                remove_proc_entry(CAN_PROC_RCVLIST_ALL, net->can.proc_dir);

        if (net->can.pde_rcvlist_fil)
                remove_proc_entry(CAN_PROC_RCVLIST_FIL, net->can.proc_dir);

        if (net->can.pde_rcvlist_inv)
                remove_proc_entry(CAN_PROC_RCVLIST_INV, net->can.proc_dir);

        if (net->can.pde_rcvlist_eff)
                remove_proc_entry(CAN_PROC_RCVLIST_EFF, net->can.proc_dir);

        if (net->can.pde_rcvlist_sff)
                remove_proc_entry(CAN_PROC_RCVLIST_SFF, net->can.proc_dir);

        if (net->can.proc_dir)
                remove_proc_entry("can", net->proc_net);
}