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linux/net/bridge/br_sysfs_if.c

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// 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 sprintf(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)
{
unsigned long flags;
flags = p->flags;
if (v)
flags |= mask;
else
flags &= ~mask;
if (flags != p->flags) {
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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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 sprintf(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);
net: bridge: add support for backup port This patch adds a new port attribute - IFLA_BRPORT_BACKUP_PORT, which allows to set a backup port to be used for known unicast traffic if the port has gone carrier down. The backup pointer is rcu protected and set only under RTNL, a counter is maintained so when deleting a port we know how many other ports reference it as a backup and we remove it from all. Also the pointer is in the first cache line which is hot at the time of the check and thus in the common case we only add one more test. The backup port will be used only for the non-flooding case since it's a part of the bridge and the flooded packets will be forwarded to it anyway. To remove the forwarding just send a 0/non-existing backup port. This is used to avoid numerous scalability problems when using MLAG most notably if we have thousands of fdbs one would need to change all of them on port carrier going down which takes too long and causes a storm of fdb notifications (and again when the port comes back up). In a Multi-chassis Link Aggregation setup usually hosts are connected to two different switches which act as a single logical switch. Those switches usually have a control and backup link between them called peerlink which might be used for communication in case a host loses connectivity to one of them. We need a fast way to failover in case a host port goes down and currently none of the solutions (like bond) cannot fulfill the requirements because the participating ports are actually the "master" devices and must have the same peerlink as their backup interface and at the same time all of them must participate in the bridge device. As Roopa noted it's normal practice in routing called fast re-route where a precalculated backup path is used when the main one is down. Another use case of this is with EVPN, having a single vxlan device which is backup of every port. Due to the nature of master devices it's not currently possible to use one device as a backup for many and still have all of them participate in the bridge (which is master itself). More detailed information about MLAG is available at the link below. https://docs.cumulusnetworks.com/display/DOCS/Multi-Chassis+Link+Aggregation+-+MLAG Further explanation and a diagram by Roopa: Two switches acting in a MLAG pair are connected by the peerlink interface which is a bridge port. the config on one of the switches looks like the below. The other switch also has a similar config. eth0 is connected to one port on the server. And the server is connected to both switches. br0 -- team0---eth0 | -- switch-peerlink Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-23 08:16:59 +00:00
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 = sprintf(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 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, 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,
net: bridge: add support for backup port This patch adds a new port attribute - IFLA_BRPORT_BACKUP_PORT, which allows to set a backup port to be used for known unicast traffic if the port has gone carrier down. The backup pointer is rcu protected and set only under RTNL, a counter is maintained so when deleting a port we know how many other ports reference it as a backup and we remove it from all. Also the pointer is in the first cache line which is hot at the time of the check and thus in the common case we only add one more test. The backup port will be used only for the non-flooding case since it's a part of the bridge and the flooded packets will be forwarded to it anyway. To remove the forwarding just send a 0/non-existing backup port. This is used to avoid numerous scalability problems when using MLAG most notably if we have thousands of fdbs one would need to change all of them on port carrier going down which takes too long and causes a storm of fdb notifications (and again when the port comes back up). In a Multi-chassis Link Aggregation setup usually hosts are connected to two different switches which act as a single logical switch. Those switches usually have a control and backup link between them called peerlink which might be used for communication in case a host loses connectivity to one of them. We need a fast way to failover in case a host port goes down and currently none of the solutions (like bond) cannot fulfill the requirements because the participating ports are actually the "master" devices and must have the same peerlink as their backup interface and at the same time all of them must participate in the bridge device. As Roopa noted it's normal practice in routing called fast re-route where a precalculated backup path is used when the main one is down. Another use case of this is with EVPN, having a single vxlan device which is backup of every port. Due to the nature of master devices it's not currently possible to use one device as a backup for many and still have all of them participate in the bridge (which is master itself). More detailed information about MLAG is available at the link below. https://docs.cumulusnetworks.com/display/DOCS/Multi-Chassis+Link+Aggregation+-+MLAG Further explanation and a diagram by Roopa: Two switches acting in a MLAG pair are connected by the peerlink interface which is a bridge port. the config on one of the switches looks like the below. The other switch also has a similar config. eth0 is connected to one port on the server. And the server is connected to both switches. br0 -- team0---eth0 | -- switch-peerlink Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-23 08:16:59 +00:00
&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;
}
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;
}