// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Userspace interface
* Linux ethernet bridge
*
* Authors:
* Lennert Buytenhek <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/netpoll.h>
#include <linux/ethtool.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <linux/if_ether.h>
#include <linux/slab.h>
#include <net/dsa.h>
#include <net/sock.h>
#include <linux/if_vlan.h>
#include <net/switchdev.h>
#include <net/net_namespace.h>
#include "br_private.h"
/*
* Determine initial path cost based on speed.
* using recommendations from 802.1d standard
*
* Since driver might sleep need to not be holding any locks.
*/
static int port_cost(struct net_device *dev)
{
struct ethtool_link_ksettings ecmd;
if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
switch (ecmd.base.speed) {
case SPEED_10000:
return 2;
case SPEED_5000:
return 3;
case SPEED_2500:
return 4;
case SPEED_1000:
return 5;
case SPEED_100:
return 19;
case SPEED_10:
return 100;
case SPEED_UNKNOWN:
return 100;
default:
if (ecmd.base.speed > SPEED_10000)
return 1;
}
}
/* Old silly heuristics based on name */
if (!strncmp(dev->name, "lec", 3))
return 7;
if (!strncmp(dev->name, "plip", 4))
return 2500;
return 100; /* assume old 10Mbps */
}
/* Check for port carrier transitions. */
void br_port_carrier_check(struct net_bridge_port *p, bool *notified)
{
struct net_device *dev = p->dev;
struct net_bridge *br = p->br;
if (!(p->flags & BR_ADMIN_COST) &&
netif_running(dev) && netif_oper_up(dev))
p->path_cost = port_cost(dev);
*notified = false;
if (!netif_running(br->dev))
return;
spin_lock_bh(&br->lock);
if (netif_running(dev) && netif_oper_up(dev)) {
if (p->state == BR_STATE_DISABLED) {
br_stp_enable_port(p);
*notified = true;
}
} else {
if (p->state != BR_STATE_DISABLED) {
br_stp_disable_port(p);
*notified = true;
}
}
spin_unlock_bh(&br->lock);
}
static void br_port_set_promisc(struct net_bridge_port *p)
{
int err = 0;
if (br_promisc_port(p))
return;
err = dev_set_promiscuity(p->dev, 1);
if (err)
return;
br_fdb_unsync_static(p->br, p);
p->flags |= BR_PROMISC;
}
static void br_port_clear_promisc(struct net_bridge_port *p)
{
int err;
/* Check if the port is already non-promisc or if it doesn't
* support UNICAST filtering. Without unicast filtering support
* we'll end up re-enabling promisc mode anyway, so just check for
* it here.
*/
if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
return;
/* Since we'll be clearing the promisc mode, program the port
* first so that we don't have interruption in traffic.
*/
err = br_fdb_sync_static(p->br, p);
if (err)
return;
dev_set_promiscuity(p->dev, -1);
p->flags &= ~BR_PROMISC;
}
/* When a port is added or removed or when certain port flags
* change, this function is called to automatically manage
* promiscuity setting of all the bridge ports. We are always called
* under RTNL so can skip using rcu primitives.
*/
void br_manage_promisc(struct net_bridge *br)
{
struct net_bridge_port *p;
bool set_all = false;
/* If vlan filtering is disabled or bridge interface is placed
* into promiscuous mode, place all ports in promiscuous mode.
*/
if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br->dev))
set_all = true;
list_for_each_entry(p, &br->port_list, list) {
if (set_all) {
br_port_set_promisc(p);
} else {
/* If the number of auto-ports is <= 1, then all other
* ports will have their output configuration
* statically specified through fdbs. Since ingress
* on the auto-port becomes forwarding/egress to other
* ports and egress configuration is statically known,
* we can say that ingress configuration of the
* auto-port is also statically known.
* This lets us disable promiscuous mode and write
* this config to hw.
*/
if ((p->dev->priv_flags & IFF_UNICAST_FLT) &&
(br->auto_cnt == 0 ||
(br->auto_cnt == 1 && br_auto_port(p))))
br_port_clear_promisc(p);
else
br_port_set_promisc(p);
}
}
}
int nbp_backup_change(struct net_bridge_port *p,
struct net_device *backup_dev)
{
struct net_bridge_port *old_backup = rtnl_dereference(p->backup_port);
struct net_bridge_port *backup_p = NULL;
ASSERT_RTNL();
if (backup_dev) {
if (!netif_is_bridge_port(backup_dev))
return -ENOENT;
backup_p = br_port_get_rtnl(backup_dev);
if (backup_p->br != p->br)
return -EINVAL;
}
if (p == backup_p)
return -EINVAL;
if (old_backup == backup_p)
return 0;
/* if the backup link is already set, clear it */
if (old_backup)
old_backup->backup_redirected_cnt--;
if (backup_p)
backup_p->backup_redirected_cnt++;
rcu_assign_pointer(p->backup_port, backup_p);
return 0;
}
static void nbp_backup_clear(struct net_bridge_port *p)
{
nbp_backup_change(p, NULL);
if (p->backup_redirected_cnt) {
struct net_bridge_port *cur_p;
list_for_each_entry(cur_p, &p->br->port_list, list) {
struct net_bridge_port *backup_p;
backup_p = rtnl_dereference(cur_p->backup_port);
if (backup_p == p)
nbp_backup_change(cur_p, NULL);
}
}
WARN_ON(rcu_access_pointer(p->backup_port) || p->backup_redirected_cnt);
}
static void nbp_update_port_count(struct net_bridge *br)
{
struct net_bridge_port *p;
u32 cnt = 0;
list_for_each_entry(p, &br->port_list, list) {
if (br_auto_port(p))
cnt++;
}
if (br->auto_cnt != cnt) {
br->auto_cnt = cnt;
br_manage_promisc(br);
}
}
static void nbp_delete_promisc(struct net_bridge_port *p)
{
/* If port is currently promiscuous, unset promiscuity.
* Otherwise, it is a static port so remove all addresses
* from it.
*/
dev_set_allmulti(p->dev, -1);
if (br_promisc_port(p))
dev_set_promiscuity(p->dev, -1);
else
br_fdb_unsync_static(p->br, p);
}
static void release_nbp(struct kobject *kobj)
{
struct net_bridge_port *p
= container_of(kobj, struct net_bridge_port, kobj);
kfree(p);
}
static void brport_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
{
struct net_bridge_port *p = kobj_to_brport(kobj);
net_ns_get_ownership(dev_net(p->dev), uid, gid);
}
static const struct kobj_type brport_ktype = {
#ifdef CONFIG_SYSFS
.sysfs_ops = &brport_sysfs_ops,
#endif
.release = release_nbp,
.get_ownership = brport_get_ownership,
};
static void destroy_nbp(struct net_bridge_port *p)
{
struct net_device *dev = p->dev;
p->br = NULL;
p->dev = NULL;
netdev_put(dev, &p->dev_tracker);
kobject_put(&p->kobj);
}
static void destroy_nbp_rcu(struct rcu_head *head)
{
struct net_bridge_port *p =
container_of(head, struct net_bridge_port, rcu);
destroy_nbp(p);
}
static unsigned get_max_headroom(struct net_bridge *br)
{
unsigned max_headroom = 0;
struct net_bridge_port *p;
list_for_each_entry(p, &br->port_list, list) {
unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
if (dev_headroom > max_headroom)
max_headroom = dev_headroom;
}
return max_headroom;
}
static void update_headroom(struct net_bridge *br, int new_hr)
{
struct net_bridge_port *p;
list_for_each_entry(p, &br->port_list, list)
netdev_set_rx_headroom(p->dev, new_hr);
br->dev->needed_headroom = new_hr;
}
/* Delete port(interface) from bridge is done in two steps.
* via RCU. First step, marks device as down. That deletes
* all the timers and stops new packets from flowing through.
*
* Final cleanup doesn't occur until after all CPU's finished
* processing packets.
*
* Protected from multiple admin operations by RTNL mutex
*/
static void del_nbp(struct net_bridge_port *p)
{
struct net_bridge *br = p->br;
struct net_device *dev = p->dev;
sysfs_remove_link(br->ifobj, p->dev->name);
nbp_delete_promisc(p);
spin_lock_bh(&br->lock);
br_stp_disable_port(p);
spin_unlock_bh(&br->lock);
br_mrp_port_del(br, p);
br_cfm_port_del(br, p);
br_ifinfo_notify(RTM_DELLINK, NULL, p);
list_del_rcu(&p->list);
if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
update_headroom(br, get_max_headroom(br));
netdev_reset_rx_headroom(dev);
nbp_vlan_flush(p);
br_fdb_delete_by_port(br, p, 0, 1);
switchdev_deferred_process();
nbp_backup_clear(p);
nbp_update_port_count(br);
netdev_upper_dev_unlink(dev, br->dev);
dev->priv_flags &= ~IFF_BRIDGE_PORT;
netdev_rx_handler_unregister(dev);
br_multicast_del_port(p);
kobject_uevent(&p->kobj, KOBJ_REMOVE);
kobject_del(&p->kobj);
br_netpoll_disable(p);
call_rcu(&p->rcu, destroy_nbp_rcu);
}
/* Delete bridge device */
void br_dev_delete(struct net_device *dev, struct list_head *head)
{
struct net_bridge *br = netdev_priv(dev);
struct net_bridge_port *p, *n;
list_for_each_entry_safe(p, n, &br->port_list, list) {
del_nbp(p);
}
br_recalculate_neigh_suppress_enabled(br);
br_fdb_delete_by_port(br, NULL, 0, 1);
cancel_delayed_work_sync(&br->gc_work);
br_sysfs_delbr(br->dev);
unregister_netdevice_queue(br->dev, head);
}
/* find an available port number */
static int find_portno(struct net_bridge *br)
{
int index;
struct net_bridge_port *p;
unsigned long *inuse;
inuse = bitmap_zalloc(BR_MAX_PORTS, GFP_KERNEL);
if (!inuse)
return -ENOMEM;
__set_bit(0, inuse); /* zero is reserved */
list_for_each_entry(p, &br->port_list, list)
__set_bit(p->port_no, inuse);
index = find_first_zero_bit(inuse, BR_MAX_PORTS);
bitmap_free(inuse);
return (index >= BR_MAX_PORTS) ? -EXFULL : index;
}
/* called with RTNL but without bridge lock */
static struct net_bridge_port *new_nbp(struct net_bridge *br,
struct net_device *dev)
{
struct net_bridge_port *p;
int index, err;
index = find_portno(br);
if (index < 0)
return ERR_PTR(index);
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (p == NULL)
return ERR_PTR(-ENOMEM);
p->br = br;
netdev_hold(dev, &p->dev_tracker, GFP_KERNEL);
p->dev = dev;
p->path_cost = port_cost(dev);
p->priority = 0x8000 >> BR_PORT_BITS;
p->port_no = index;
p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD;
br_init_port(p);
br_set_state(p, BR_STATE_DISABLED);
br_stp_port_timer_init(p);
err = br_multicast_add_port(p);
if (err) {
netdev_put(dev, &p->dev_tracker);
kfree(p);
p = ERR_PTR(err);
}
return p;
}
int br_add_bridge(struct net *net, const char *name)
{
struct net_device *dev;
int res;
dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
br_dev_setup);
if (!dev)
return -ENOMEM;
dev_net_set(dev, net);
dev->rtnl_link_ops = &br_link_ops;
res = register_netdevice(dev);
if (res)
free_netdev(dev);
return res;
}
int br_del_bridge(struct net *net, const char *name)
{
struct net_device *dev;
int ret = 0;
dev = __dev_get_by_name(net, name);
if (dev == NULL)
ret = -ENXIO; /* Could not find device */
else if (!netif_is_bridge_master(dev)) {
/* Attempt to delete non bridge device! */
ret = -EPERM;
}
else if (dev->flags & IFF_UP) {
/* Not shutdown yet. */
ret = -EBUSY;
}
else
br_dev_delete(dev, NULL);
return ret;
}
/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
static int br_mtu_min(const struct net_bridge *br)
{
const struct net_bridge_port *p;
int ret_mtu = 0;
list_for_each_entry(p, &br->port_list, list)
if (!ret_mtu || ret_mtu > p->dev->mtu)
ret_mtu = p->dev->mtu;
return ret_mtu ? ret_mtu : ETH_DATA_LEN;
}
void br_mtu_auto_adjust(struct net_bridge *br)
{
ASSERT_RTNL();
/* if the bridge MTU was manually configured don't mess with it */
if (br_opt_get(br, BROPT_MTU_SET_BY_USER))
return;
/* change to the minimum MTU and clear the flag which was set by
* the bridge ndo_change_mtu callback
*/
dev_set_mtu(br->dev, br_mtu_min(br));
br_opt_toggle(br, BROPT_MTU_SET_BY_USER, false);
}
static void br_set_gso_limits(struct net_bridge *br)
{
unsigned int tso_max_size = TSO_MAX_SIZE;
const struct net_bridge_port *p;
u16 tso_max_segs = TSO_MAX_SEGS;
list_for_each_entry(p, &br->port_list, list) {
tso_max_size = min(tso_max_size, p->dev->tso_max_size);
tso_max_segs = min(tso_max_segs, p->dev->tso_max_segs);
}
netif_set_tso_max_size(br->dev, tso_max_size);
netif_set_tso_max_segs(br->dev, tso_max_segs);
}
/*
* Recomputes features using slave's features
*/
netdev_features_t br_features_recompute(struct net_bridge *br,
netdev_features_t features)
{
struct net_bridge_port *p;
netdev_features_t mask;
if (list_empty(&br->port_list))
return features;
mask = features;
features &= ~NETIF_F_ONE_FOR_ALL;
list_for_each_entry(p, &br->port_list, list) {
features = netdev_increment_features(features,
p->dev->features, mask);
}
features = netdev_add_tso_features(features, mask);
return features;
}
/* called with RTNL */
int br_add_if(struct net_bridge *br, struct net_device *dev,
struct netlink_ext_ack *extack)
{
struct net_bridge_port *p;
int err = 0;
unsigned br_hr, dev_hr;
bool changed_addr, fdb_synced = false;
/* Don't allow bridging non-ethernet like devices. */
if ((dev->flags & IFF_LOOPBACK) ||
dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
!is_valid_ether_addr(dev->dev_addr))
return -EINVAL;
/* No bridging of bridges */
if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
NL_SET_ERR_MSG(extack,
"Can not enslave a bridge to a bridge");
return -ELOOP;
}
/* Device has master upper dev */
if (netdev_master_upper_dev_get(dev))
return -EBUSY;
/* No bridging devices that dislike that (e.g. wireless) */
if (dev->priv_flags & IFF_DONT_BRIDGE) {
NL_SET_ERR_MSG(extack,
"Device does not allow enslaving to a bridge");
return -EOPNOTSUPP;
}
p = new_nbp(br, dev);
if (IS_ERR(p))
return PTR_ERR(p);
call_netdevice_notifiers(NETDEV_JOIN, dev);
err = dev_set_allmulti(dev, 1);
if (err) {
br_multicast_del_port(p);
netdev_put(dev, &p->dev_tracker);
kfree(p); /* kobject not yet init'd, manually free */
goto err1;
}
err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
SYSFS_BRIDGE_PORT_ATTR);
if (err)
goto err2;
err = br_sysfs_addif(p);
if (err)
goto err2;
err = br_netpoll_enable(p);
if (err)
goto err3;
err = netdev_rx_handler_register(dev, br_get_rx_handler(dev), p);
if (err)
goto err4;
dev->priv_flags |= IFF_BRIDGE_PORT;
err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, extack);
if (err)
goto err5;
dev_disable_lro(dev);
list_add_rcu(&p->list, &br->port_list);
nbp_update_port_count(br);
if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) {
/* When updating the port count we also update all ports'
* promiscuous mode.
* A port leaving promiscuous mode normally gets the bridge's
* fdb synced to the unicast filter (if supported), however,
* `br_port_clear_promisc` does not distinguish between
* non-promiscuous ports and *new* ports, so we need to
* sync explicitly here.
*/
fdb_synced = br_fdb_sync_static(br, p) == 0;
if (!fdb_synced)
netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n");
}
netdev_update_features(br->dev);
br_hr = br->dev->needed_headroom;
dev_hr = netdev_get_fwd_headroom(dev);
if (br_hr < dev_hr)
update_headroom(br, dev_hr);
else
netdev_set_rx_headroom(dev, br_hr);
if (br_fdb_add_local(br, p, dev->dev_addr, 0))
netdev_err(dev, "failed insert local address bridge forwarding table\n");
if (br->dev->addr_assign_type != NET_ADDR_SET) {
/* Ask for permission to use this MAC address now, even if we
* don't end up choosing it below.
*/
err = dev_pre_changeaddr_notify(br->dev, dev->dev_addr, extack);
if (err)
goto err6;
}
err = nbp_vlan_init(p, extack);
if (err) {
netdev_err(dev, "failed to initialize vlan filtering on this port\n");
goto err6;
}
spin_lock_bh(&br->lock);
changed_addr = br_stp_recalculate_bridge_id(br);
if (netif_running(dev) && netif_oper_up(dev) &&
(br->dev->flags & IFF_UP))
br_stp_enable_port(p);
spin_unlock_bh(&br->lock);
br_ifinfo_notify(RTM_NEWLINK, NULL, p);
if (changed_addr)
call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
br_mtu_auto_adjust(br);
br_set_gso_limits(br);
kobject_uevent(&p->kobj, KOBJ_ADD);
return 0;
err6:
if (fdb_synced)
br_fdb_unsync_static(br, p);
list_del_rcu(&p->list);
br_fdb_delete_by_port(br, p, 0, 1);
nbp_update_port_count(br);
netdev_upper_dev_unlink(dev, br->dev);
err5:
dev->priv_flags &= ~IFF_BRIDGE_PORT;
netdev_rx_handler_unregister(dev);
err4:
br_netpoll_disable(p);
err3:
sysfs_remove_link(br->ifobj, p->dev->name);
err2:
br_multicast_del_port(p);
netdev_put(dev, &p->dev_tracker);
kobject_put(&p->kobj);
dev_set_allmulti(dev, -1);
err1:
return err;
}
/* called with RTNL */
int br_del_if(struct net_bridge *br, struct net_device *dev)
{
struct net_bridge_port *p;
bool changed_addr;
p = br_port_get_rtnl(dev);
if (!p || p->br != br)
return -EINVAL;
/* Since more than one interface can be attached to a bridge,
* there still maybe an alternate path for netconsole to use;
* therefore there is no reason for a NETDEV_RELEASE event.
*/
del_nbp(p);
br_mtu_auto_adjust(br);
br_set_gso_limits(br);
spin_lock_bh(&br->lock);
changed_addr = br_stp_recalculate_bridge_id(br);
spin_unlock_bh(&br->lock);
if (changed_addr)
call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
netdev_update_features(br->dev);
return 0;
}
void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
{
struct net_bridge *br = p->br;
if (mask & BR_AUTO_MASK)
nbp_update_port_count(br);
if (mask & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS))
br_recalculate_neigh_suppress_enabled(br);
}
bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag)
{
struct net_bridge_port *p;
p = br_port_get_rtnl_rcu(dev);
if (!p)
return false;
return p->flags & flag;
}
EXPORT_SYMBOL_GPL(br_port_flag_is_set);
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