br_sysfs_if.c

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/*
 *  Sysfs attributes of bridge ports
 *  Linux ethernet bridge
 *
 *  Authors:
 *  Stephen Hemminger       <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/if_bridge.h>
#include <linux/rtnetlink.h>
#include <linux/spinlock.h>

#include "br_private.h"

struct brport_attribute {
    struct attribute    attr;
    ssize_t (*show)(struct net_bridge_port *, char *);
    int (*store)(struct net_bridge_port *, unsigned long);
};

#define BRPORT_ATTR(_name,_mode,_show,_store)               \
const struct brport_attribute brport_attr_##_name = {           \
    .attr = {.name = __stringify(_name),            \
         .mode = _mode },               \
    .show   = _show,                    \
    .store  = _store,                   \
};

static ssize_t show_path_cost(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->path_cost);
}

static BRPORT_ATTR(path_cost, S_IRUGO | S_IWUSR,
           show_path_cost, br_stp_set_path_cost);

static ssize_t show_priority(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->priority);
}

static BRPORT_ATTR(priority, S_IRUGO | S_IWUSR,
             show_priority, br_stp_set_port_priority);

static ssize_t show_designated_root(struct net_bridge_port *p, char *buf)
{
    return br_show_bridge_id(buf, &p->designated_root);
}
static BRPORT_ATTR(designated_root, S_IRUGO, show_designated_root, NULL);

static ssize_t show_designated_bridge(struct net_bridge_port *p, char *buf)
{
    return br_show_bridge_id(buf, &p->designated_bridge);
}
static BRPORT_ATTR(designated_bridge, S_IRUGO, show_designated_bridge, NULL);

static ssize_t show_designated_port(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->designated_port);
}
static BRPORT_ATTR(designated_port, S_IRUGO, show_designated_port, NULL);

static ssize_t show_designated_cost(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->designated_cost);
}
static BRPORT_ATTR(designated_cost, S_IRUGO, show_designated_cost, NULL);

static ssize_t show_port_id(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "0x%x\n", p->port_id);
}
static BRPORT_ATTR(port_id, S_IRUGO, show_port_id, NULL);

static ssize_t show_port_no(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "0x%x\n", p->port_no);
}

static BRPORT_ATTR(port_no, S_IRUGO, show_port_no, NULL);

static ssize_t show_change_ack(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->topology_change_ack);
}
static BRPORT_ATTR(change_ack, S_IRUGO, show_change_ack, NULL);

static ssize_t show_config_pending(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->config_pending);
}
static BRPORT_ATTR(config_pending, S_IRUGO, show_config_pending, NULL);

static ssize_t show_port_state(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->state);
}
static BRPORT_ATTR(state, S_IRUGO, show_port_state, NULL);

static ssize_t show_message_age_timer(struct net_bridge_port *p,
                        char *buf)
{
    return sprintf(buf, "%ld\n", br_timer_value(&p->message_age_timer));
}
static BRPORT_ATTR(message_age_timer, S_IRUGO, show_message_age_timer, NULL);

static ssize_t show_forward_delay_timer(struct net_bridge_port *p,
                        char *buf)
{
    return sprintf(buf, "%ld\n", br_timer_value(&p->forward_delay_timer));
}
static BRPORT_ATTR(forward_delay_timer, S_IRUGO, show_forward_delay_timer, NULL);

static ssize_t show_hold_timer(struct net_bridge_port *p,
                        char *buf)
{
    return sprintf(buf, "%ld\n", br_timer_value(&p->hold_timer));
}
static BRPORT_ATTR(hold_timer, S_IRUGO, show_hold_timer, NULL);

static int store_flush(struct net_bridge_port *p, unsigned long v)
{
    br_fdb_delete_by_port(p->br, p, 0); // Don't delete local entry
    return 0;
}
static BRPORT_ATTR(flush, S_IWUSR, NULL, store_flush);

static ssize_t show_hairpin_mode(struct net_bridge_port *p, char *buf)
{
    int hairpin_mode = (p->flags & BR_HAIRPIN_MODE) ? 1 : 0;
    return sprintf(buf, "%d\n", hairpin_mode);
}
static int store_hairpin_mode(struct net_bridge_port *p, unsigned long v)
{
    if (v)
        p->flags |= BR_HAIRPIN_MODE;
    else
        p->flags &= ~BR_HAIRPIN_MODE;
    return 0;
}
static BRPORT_ATTR(hairpin_mode, S_IRUGO | S_IWUSR,
           show_hairpin_mode, store_hairpin_mode);

#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
{
    return sprintf(buf, "%d\n", p->multicast_router);
}

static int store_multicast_router(struct net_bridge_port *p,
                      unsigned long v)
{
    return br_multicast_set_port_router(p, v);
}
static BRPORT_ATTR(multicast_router, S_IRUGO | S_IWUSR, show_multicast_router,
           store_multicast_router);
#endif

static const struct brport_attribute *brport_attrs[] = {
    &brport_attr_path_cost,
    &brport_attr_priority,
    &brport_attr_port_id,
    &brport_attr_port_no,
    &brport_attr_designated_root,
    &brport_attr_designated_bridge,
    &brport_attr_designated_port,
    &brport_attr_designated_cost,
    &brport_attr_state,
    &brport_attr_change_ack,
    &brport_attr_config_pending,
    &brport_attr_message_age_timer,
    &brport_attr_forward_delay_timer,
    &brport_attr_hold_timer,
    &brport_attr_flush,
    &brport_attr_hairpin_mode,
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
    &brport_attr_multicast_router,
#endif
    NULL
};

#define to_brport_attr(_at) container_of(_at, struct brport_attribute, attr)
#define to_brport(obj)  container_of(obj, struct net_bridge_port, kobj)

static ssize_t brport_show(struct kobject * kobj,
               struct attribute * attr, char * buf)
{
    struct brport_attribute * brport_attr = to_brport_attr(attr);
    struct net_bridge_port * p = to_brport(kobj);

    return brport_attr->show(p, buf);
}

static ssize_t brport_store(struct kobject * kobj,
                struct attribute * attr,
                const char * buf, size_t count)
{
    struct brport_attribute * brport_attr = to_brport_attr(attr);
    struct net_bridge_port * p = to_brport(kobj);
    ssize_t ret = -EINVAL;
    char *endp;
    unsigned long val;

    if (!capable(CAP_NET_ADMIN))
        return -EPERM;

    val = simple_strtoul(buf, &endp, 0);
    if (endp != buf) {
        if (!rtnl_trylock())
            return restart_syscall();
        if (p->dev && p->br && brport_attr->store) {
            spin_lock_bh(&p->br->lock);
            ret = brport_attr->store(p, val);
            spin_unlock_bh(&p->br->lock);
            if (ret == 0)
                ret = count;
        }
        rtnl_unlock();
    }
    return ret;
}

const struct sysfs_ops brport_sysfs_ops = {
    .show = brport_show,
    .store = brport_store,
};

/*
 * Add sysfs entries to ethernet device added to a bridge.
 * Creates a brport subdirectory with bridge attributes.
 * Puts symlink in bridge's brif subdirectory
 */
int br_sysfs_addif(struct net_bridge_port *p)
{
    struct net_bridge *br = p->br;
    const struct brport_attribute **a;
    int err;

    err = sysfs_create_link(&p->kobj, &br->dev->dev.kobj,
                SYSFS_BRIDGE_PORT_LINK);
    if (err)
        return err;

    for (a = brport_attrs; *a; ++a) {
        err = sysfs_create_file(&p->kobj, &((*a)->attr));
        if (err)
            return err;
    }

    strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);
    return sysfs_create_link(br->ifobj, &p->kobj, p->sysfs_name);
}

/* Rename bridge's brif symlink */
int br_sysfs_renameif(struct net_bridge_port *p)
{
    struct net_bridge *br = p->br;
    int err;

    /* If a rename fails, the rollback will cause another
     * rename call with the existing name.
     */
    if (!strncmp(p->sysfs_name, p->dev->name, IFNAMSIZ))
        return 0;

    err = sysfs_rename_link(br->ifobj, &p->kobj,
                p->sysfs_name, p->dev->name);
    if (err)
        netdev_notice(br->dev, "unable to rename link %s to %s",
                  p->sysfs_name, p->dev->name);
    else
        strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);

    return err;
}