proc.c

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/*
 * 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\n",
               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;
    struct hlist_node *n;

    hlist_for_each_entry_rcu(r, n, 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)
{
    seq_putc(m, '\n');
    seq_printf(m, " %8ld transmitted frames (TXF)\n", can_stats.tx_frames);
    seq_printf(m, " %8ld received frames (RXF)\n", can_stats.rx_frames);
    seq_printf(m, " %8ld matched frames (RXMF)\n", can_stats.matches);

    seq_putc(m, '\n');

    if (can_stattimer.function == can_stat_update) {
        seq_printf(m, " %8ld %% total match ratio (RXMR)\n",
                can_stats.total_rx_match_ratio);

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

        seq_putc(m, '\n');

        seq_printf(m, " %8ld %% current match ratio (CRXMR)\n",
                can_stats.current_rx_match_ratio);

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

        seq_putc(m, '\n');

        seq_printf(m, " %8ld %% max match ratio (MRXMR)\n",
                can_stats.max_rx_match_ratio);

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

        seq_putc(m, '\n');
    }

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

    if (can_pstats.stats_reset)
        seq_printf(m, "\n %8ld statistic resets (STR)\n",
                can_pstats.stats_reset);

    if (can_pstats.user_reset)
        seq_printf(m, " %8ld user statistic resets (USTR)\n",
                can_pstats.user_reset);

    seq_putc(m, '\n');
    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.\n",
                can_pstats.stats_reset + 1);

    } else {
        if (can_stats.jiffies_init != jiffies)
            can_init_stats();

        seq_printf(m, "Performed statistic reset #%ld.\n",
                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\n", 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)\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)m->private;
    struct net_device *dev;
    struct dev_rcv_lists *d;

    seq_printf(m, "\nreceive list '%s':\n", 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, '\n');
    return 0;
}

static int can_rcvlist_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, can_rcvlist_proc_show, PDE(inode)->data);
}

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 wether 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)\n", 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, "\nreceive list 'rx_sff':\n");

    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, '\n');
    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?\n");
        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)
        proc_net_remove(&init_net, "can");
}