// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      Sysfs attributes of bridge ports
 *      Linux ethernet bridge
 *
 *      Authors:
 *      Stephen Hemminger               <shemminger@osdl.org>
 */

#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 <linux/sched/signal.h>

#include "br_private.h"

/* IMPORTANT: new bridge port options must be added with netlink support only
 *            please do not add new sysfs entries
 */

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

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

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

#define BRPORT_ATTR_FLAG(_name, _mask)                          \
static ssize_t show_##_name(struct net_bridge_port *p, char *buf) \
{                                                               \
        return sysfs_emit(buf, "%d\n", !!(p->flags & _mask));   \
}                                                               \
static int store_##_name(struct net_bridge_port *p, unsigned long v) \
{                                                               \
        return store_flag(p, v, _mask);                         \
}                                                               \
static BRPORT_ATTR(_name, 0644,                                 \
                   show_##_name, store_##_name)

static int store_flag(struct net_bridge_port *p, unsigned long v,
                      unsigned long mask)
{
        struct netlink_ext_ack extack = {0};
        unsigned long flags = p->flags;
        int err;

        if (v)
                flags |= mask;
        else
                flags &= ~mask;

        if (flags != p->flags) {
                err = br_switchdev_set_port_flag(p, flags, mask, &extack);
                if (err) {
                        netdev_err(p->dev, "%s\n", extack._msg);
                        return err;
                }

                p->flags = flags;
                br_port_flags_change(p, mask);
        }
        return 0;
}

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

static BRPORT_ATTR(path_cost, 0644,
                   show_path_cost, br_stp_set_path_cost);

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

static BRPORT_ATTR(priority, 0644,
                         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, 0444, 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, 0444, show_designated_bridge, NULL);

static ssize_t show_designated_port(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%d\n", p->designated_port);
}
static BRPORT_ATTR(designated_port, 0444, show_designated_port, NULL);

static ssize_t show_designated_cost(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%d\n", p->designated_cost);
}
static BRPORT_ATTR(designated_cost, 0444, show_designated_cost, NULL);

static ssize_t show_port_id(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "0x%x\n", p->port_id);
}
static BRPORT_ATTR(port_id, 0444, show_port_id, NULL);

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

static BRPORT_ATTR(port_no, 0444, show_port_no, NULL);

static ssize_t show_change_ack(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%d\n", p->topology_change_ack);
}
static BRPORT_ATTR(change_ack, 0444, show_change_ack, NULL);

static ssize_t show_config_pending(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%d\n", p->config_pending);
}
static BRPORT_ATTR(config_pending, 0444, show_config_pending, NULL);

static ssize_t show_port_state(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%d\n", p->state);
}
static BRPORT_ATTR(state, 0444, show_port_state, NULL);

static ssize_t show_message_age_timer(struct net_bridge_port *p,
                                            char *buf)
{
        return sysfs_emit(buf, "%ld\n", br_timer_value(&p->message_age_timer));
}
static BRPORT_ATTR(message_age_timer, 0444, show_message_age_timer, NULL);

static ssize_t show_forward_delay_timer(struct net_bridge_port *p,
                                            char *buf)
{
        return sysfs_emit(buf, "%ld\n", br_timer_value(&p->forward_delay_timer));
}
static BRPORT_ATTR(forward_delay_timer, 0444, show_forward_delay_timer, NULL);

static ssize_t show_hold_timer(struct net_bridge_port *p,
                                            char *buf)
{
        return sysfs_emit(buf, "%ld\n", br_timer_value(&p->hold_timer));
}
static BRPORT_ATTR(hold_timer, 0444, 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, 0); // Don't delete local entry
        return 0;
}
static BRPORT_ATTR(flush, 0200, NULL, store_flush);

static ssize_t show_group_fwd_mask(struct net_bridge_port *p, char *buf)
{
        return sysfs_emit(buf, "%#x\n", p->group_fwd_mask);
}

static int store_group_fwd_mask(struct net_bridge_port *p,
                                unsigned long v)
{
        if (v & BR_GROUPFWD_MACPAUSE)
                return -EINVAL;
        p->group_fwd_mask = v;

        return 0;
}
static BRPORT_ATTR(group_fwd_mask, 0644, show_group_fwd_mask,
                   store_group_fwd_mask);

static ssize_t show_backup_port(struct net_bridge_port *p, char *buf)
{
        struct net_bridge_port *backup_p;
        int ret = 0;

        rcu_read_lock();
        backup_p = rcu_dereference(p->backup_port);
        if (backup_p)
                ret = sysfs_emit(buf, "%s\n", backup_p->dev->name);
        rcu_read_unlock();

        return ret;
}

static int store_backup_port(struct net_bridge_port *p, char *buf)
{
        struct net_device *backup_dev = NULL;
        char *nl = strchr(buf, '\n');

        if (nl)
                *nl = '\0';

        if (strlen(buf) > 0) {
                backup_dev = __dev_get_by_name(dev_net(p->dev), buf);
                if (!backup_dev)
                        return -ENOENT;
        }

        return nbp_backup_change(p, backup_dev);
}
static BRPORT_ATTR_RAW(backup_port, 0644, show_backup_port, store_backup_port);

BRPORT_ATTR_FLAG(hairpin_mode, BR_HAIRPIN_MODE);
BRPORT_ATTR_FLAG(bpdu_guard, BR_BPDU_GUARD);
BRPORT_ATTR_FLAG(root_block, BR_ROOT_BLOCK);
BRPORT_ATTR_FLAG(learning, BR_LEARNING);
BRPORT_ATTR_FLAG(unicast_flood, BR_FLOOD);
BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
BRPORT_ATTR_FLAG(multicast_flood, BR_MCAST_FLOOD);
BRPORT_ATTR_FLAG(broadcast_flood, BR_BCAST_FLOOD);
BRPORT_ATTR_FLAG(neigh_suppress, BR_NEIGH_SUPPRESS);
BRPORT_ATTR_FLAG(isolated, BR_ISOLATED);

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

static int store_multicast_router(struct net_bridge_port *p,
                                      unsigned long v)
{
        return br_multicast_set_port_router(&p->multicast_ctx, v);
}
static BRPORT_ATTR(multicast_router, 0644, show_multicast_router,
                   store_multicast_router);

BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
BRPORT_ATTR_FLAG(multicast_to_unicast, BR_MULTICAST_TO_UNICAST);
#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,
        &brport_attr_bpdu_guard,
        &brport_attr_root_block,
        &brport_attr_learning,
        &brport_attr_unicast_flood,
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
        &brport_attr_multicast_router,
        &brport_attr_multicast_fast_leave,
        &brport_attr_multicast_to_unicast,
#endif
        &brport_attr_proxyarp,
        &brport_attr_proxyarp_wifi,
        &brport_attr_multicast_flood,
        &brport_attr_broadcast_flood,
        &brport_attr_group_fwd_mask,
        &brport_attr_neigh_suppress,
        &brport_attr_isolated,
        &brport_attr_backup_port,
        NULL
};

#define to_brport_attr(_at) container_of(_at, struct brport_attribute, attr)

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 = kobj_to_brport(kobj);

        if (!brport_attr->show)
                return -EINVAL;

        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 = kobj_to_brport(kobj);
        ssize_t ret = -EINVAL;
        unsigned long val;
        char *endp;

        if (!ns_capable(dev_net(p->dev)->user_ns, CAP_NET_ADMIN))
                return -EPERM;

        if (!rtnl_trylock())
                return restart_syscall();

        if (brport_attr->store_raw) {
                char *buf_copy;

                buf_copy = kstrndup(buf, count, GFP_KERNEL);
                if (!buf_copy) {
                        ret = -ENOMEM;
                        goto out_unlock;
                }
                spin_lock_bh(&p->br->lock);
                ret = brport_attr->store_raw(p, buf_copy);
                spin_unlock_bh(&p->br->lock);
                kfree(buf_copy);
        } else if (brport_attr->store) {
                val = simple_strtoul(buf, &endp, 0);
                if (endp == buf)
                        goto out_unlock;
                spin_lock_bh(&p->br->lock);
                ret = brport_attr->store(p, val);
                spin_unlock_bh(&p->br->lock);
        }

        if (!ret) {
                br_ifinfo_notify(RTM_NEWLINK, NULL, p);
                ret = count;
        }
out_unlock:
        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;
        }

        strscpy(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
                strscpy(p->sysfs_name, p->dev->name, IFNAMSIZ);

        return err;
}