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alistair23-linux/net/bridge/br_device.c
Nikolay Aleksandrov eb7935830d net: bridge: use rhashtable for fdbs 
Before this patch the bridge used a fixed 256 element hash table which
was fine for small use cases (in my tests it starts to degrade
above 1000 entries), but it wasn't enough for medium or large
scale deployments. Modern setups have thousands of participants in a
single bridge, even only enabling vlans and adding a few thousand vlan
entries will cause a few thousand fdbs to be automatically inserted per
participating port. So we need to scale the fdb table considerably to
cope with modern workloads, and this patch converts it to use a
rhashtable for its operations thus improving the bridge scalability.
Tests show the following results (10 runs each), at up to 1000 entries
rhashtable is ~3% slower, at 2000 rhashtable is 30% faster, at 3000 it
is 2 times faster and at 30000 it is 50 times faster.
Obviously this happens because of the properties of the two constructs
and is expected, rhashtable keeps pretty much a constant time even with
10000000 entries (tested), while the fixed hash table struggles
considerably even above 10000.
As a side effect this also reduces the net_bridge struct size from 3248
bytes to 1344 bytes. Also note that the key struct is 8 bytes.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 15:10:01 -05:00

452 lines
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/*
* Device handling code
* Linux ethernet bridge
*
* Authors:
* Lennert Buytenhek <buytenh@gnu.org>
*
* 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/kernel.h>
#include <linux/netdevice.h>
#include <linux/netpoll.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/list.h>
#include <linux/netfilter_bridge.h>
#include <linux/uaccess.h>
#include "br_private.h"
#define COMMON_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA | \
NETIF_F_GSO_MASK | NETIF_F_HW_CSUM)
const struct nf_br_ops __rcu *nf_br_ops __read_mostly;
EXPORT_SYMBOL_GPL(nf_br_ops);
static struct lock_class_key bridge_netdev_addr_lock_key;
/* net device transmit always called with BH disabled */
netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
struct net_bridge_fdb_entry *dst;
struct net_bridge_mdb_entry *mdst;
struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
const struct nf_br_ops *nf_ops;
const unsigned char *dest;
struct ethhdr *eth;
u16 vid = 0;
rcu_read_lock();
nf_ops = rcu_dereference(nf_br_ops);
if (nf_ops && nf_ops->br_dev_xmit_hook(skb)) {
rcu_read_unlock();
return NETDEV_TX_OK;
}
u64_stats_update_begin(&brstats->syncp);
brstats->tx_packets++;
brstats->tx_bytes += skb->len;
u64_stats_update_end(&brstats->syncp);
br_switchdev_frame_unmark(skb);
BR_INPUT_SKB_CB(skb)->brdev = dev;
skb_reset_mac_header(skb);
eth = eth_hdr(skb);
skb_pull(skb, ETH_HLEN);
if (!br_allowed_ingress(br, br_vlan_group_rcu(br), skb, &vid))
goto out;
if (IS_ENABLED(CONFIG_INET) &&
(eth->h_proto == htons(ETH_P_ARP) ||
eth->h_proto == htons(ETH_P_RARP)) &&
br->neigh_suppress_enabled) {
br_do_proxy_suppress_arp(skb, br, vid, NULL);
} else if (IS_ENABLED(CONFIG_IPV6) &&
skb->protocol == htons(ETH_P_IPV6) &&
br->neigh_suppress_enabled &&
pskb_may_pull(skb, sizeof(struct ipv6hdr) +
sizeof(struct nd_msg)) &&
ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
struct nd_msg *msg, _msg;
msg = br_is_nd_neigh_msg(skb, &_msg);
if (msg)
br_do_suppress_nd(skb, br, vid, NULL, msg);
}
dest = eth_hdr(skb)->h_dest;
if (is_broadcast_ether_addr(dest)) {
br_flood(br, skb, BR_PKT_BROADCAST, false, true);
} else if (is_multicast_ether_addr(dest)) {
if (unlikely(netpoll_tx_running(dev))) {
br_flood(br, skb, BR_PKT_MULTICAST, false, true);
goto out;
}
if (br_multicast_rcv(br, NULL, skb, vid)) {
kfree_skb(skb);
goto out;
}
mdst = br_mdb_get(br, skb, vid);
if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
br_multicast_querier_exists(br, eth_hdr(skb)))
br_multicast_flood(mdst, skb, false, true);
else
br_flood(br, skb, BR_PKT_MULTICAST, false, true);
} else if ((dst = br_fdb_find_rcu(br, dest, vid)) != NULL) {
br_forward(dst->dst, skb, false, true);
} else {
br_flood(br, skb, BR_PKT_UNICAST, false, true);
}
out:
rcu_read_unlock();
return NETDEV_TX_OK;
}
static void br_set_lockdep_class(struct net_device *dev)
{
lockdep_set_class(&dev->addr_list_lock, &bridge_netdev_addr_lock_key);
}
static int br_dev_init(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
int err;
br->stats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
if (!br->stats)
return -ENOMEM;
err = br_fdb_hash_init(br);
if (err) {
free_percpu(br->stats);
return err;
}
err = br_vlan_init(br);
if (err) {
free_percpu(br->stats);
br_fdb_hash_fini(br);
return err;
}
err = br_multicast_init_stats(br);
if (err) {
free_percpu(br->stats);
br_vlan_flush(br);
br_fdb_hash_fini(br);
}
br_set_lockdep_class(dev);
return err;
}
static void br_dev_uninit(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
br_multicast_dev_del(br);
br_multicast_uninit_stats(br);
br_vlan_flush(br);
br_fdb_hash_fini(br);
free_percpu(br->stats);
}
static int br_dev_open(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
netdev_update_features(dev);
netif_start_queue(dev);
br_stp_enable_bridge(br);
br_multicast_open(br);
return 0;
}
static void br_dev_set_multicast_list(struct net_device *dev)
{
}
static void br_dev_change_rx_flags(struct net_device *dev, int change)
{
if (change & IFF_PROMISC)
br_manage_promisc(netdev_priv(dev));
}
static int br_dev_stop(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
br_stp_disable_bridge(br);
br_multicast_stop(br);
netif_stop_queue(dev);
return 0;
}
static void br_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
struct net_bridge *br = netdev_priv(dev);
struct pcpu_sw_netstats tmp, sum = { 0 };
unsigned int cpu;
for_each_possible_cpu(cpu) {
unsigned int start;
const struct pcpu_sw_netstats *bstats
= per_cpu_ptr(br->stats, cpu);
do {
start = u64_stats_fetch_begin_irq(&bstats->syncp);
memcpy(&tmp, bstats, sizeof(tmp));
} while (u64_stats_fetch_retry_irq(&bstats->syncp, start));
sum.tx_bytes += tmp.tx_bytes;
sum.tx_packets += tmp.tx_packets;
sum.rx_bytes += tmp.rx_bytes;
sum.rx_packets += tmp.rx_packets;
}
stats->tx_bytes = sum.tx_bytes;
stats->tx_packets = sum.tx_packets;
stats->rx_bytes = sum.rx_bytes;
stats->rx_packets = sum.rx_packets;
}
static int br_change_mtu(struct net_device *dev, int new_mtu)
{
struct net_bridge *br = netdev_priv(dev);
if (new_mtu > br_min_mtu(br))
return -EINVAL;
dev->mtu = new_mtu;
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
/* remember the MTU in the rtable for PMTU */
dst_metric_set(&br->fake_rtable.dst, RTAX_MTU, new_mtu);
#endif
return 0;
}
/* Allow setting mac address to any valid ethernet address. */
static int br_set_mac_address(struct net_device *dev, void *p)
{
struct net_bridge *br = netdev_priv(dev);
struct sockaddr *addr = p;
if (!is_valid_ether_addr(addr->sa_data))
return -EADDRNOTAVAIL;
spin_lock_bh(&br->lock);
if (!ether_addr_equal(dev->dev_addr, addr->sa_data)) {
/* Mac address will be changed in br_stp_change_bridge_id(). */
br_stp_change_bridge_id(br, addr->sa_data);
}
spin_unlock_bh(&br->lock);
return 0;
}
static void br_getinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
strlcpy(info->driver, "bridge", sizeof(info->driver));
strlcpy(info->version, BR_VERSION, sizeof(info->version));
strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
strlcpy(info->bus_info, "N/A", sizeof(info->bus_info));
}
static netdev_features_t br_fix_features(struct net_device *dev,
netdev_features_t features)
{
struct net_bridge *br = netdev_priv(dev);
return br_features_recompute(br, features);
}
#ifdef CONFIG_NET_POLL_CONTROLLER
static void br_poll_controller(struct net_device *br_dev)
{
}
static void br_netpoll_cleanup(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
struct net_bridge_port *p;
list_for_each_entry(p, &br->port_list, list)
br_netpoll_disable(p);
}
static int __br_netpoll_enable(struct net_bridge_port *p)
{
struct netpoll *np;
int err;
np = kzalloc(sizeof(*p->np), GFP_KERNEL);
if (!np)
return -ENOMEM;
err = __netpoll_setup(np, p->dev);
if (err) {
kfree(np);
return err;
}
p->np = np;
return err;
}
int br_netpoll_enable(struct net_bridge_port *p)
{
if (!p->br->dev->npinfo)
return 0;
return __br_netpoll_enable(p);
}
static int br_netpoll_setup(struct net_device *dev, struct netpoll_info *ni)
{
struct net_bridge *br = netdev_priv(dev);
struct net_bridge_port *p;
int err = 0;
list_for_each_entry(p, &br->port_list, list) {
if (!p->dev)
continue;
err = __br_netpoll_enable(p);
if (err)
goto fail;
}
out:
return err;
fail:
br_netpoll_cleanup(dev);
goto out;
}
void br_netpoll_disable(struct net_bridge_port *p)
{
struct netpoll *np = p->np;
if (!np)
return;
p->np = NULL;
__netpoll_free_async(np);
}
#endif
static int br_add_slave(struct net_device *dev, struct net_device *slave_dev,
struct netlink_ext_ack *extack)
{
struct net_bridge *br = netdev_priv(dev);
return br_add_if(br, slave_dev, extack);
}
static int br_del_slave(struct net_device *dev, struct net_device *slave_dev)
{
struct net_bridge *br = netdev_priv(dev);
return br_del_if(br, slave_dev);
}
static const struct ethtool_ops br_ethtool_ops = {
.get_drvinfo = br_getinfo,
.get_link = ethtool_op_get_link,
};
static const struct net_device_ops br_netdev_ops = {
.ndo_open = br_dev_open,
.ndo_stop = br_dev_stop,
.ndo_init = br_dev_init,
.ndo_uninit = br_dev_uninit,
.ndo_start_xmit = br_dev_xmit,
.ndo_get_stats64 = br_get_stats64,
.ndo_set_mac_address = br_set_mac_address,
.ndo_set_rx_mode = br_dev_set_multicast_list,
.ndo_change_rx_flags = br_dev_change_rx_flags,
.ndo_change_mtu = br_change_mtu,
.ndo_do_ioctl = br_dev_ioctl,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_netpoll_setup = br_netpoll_setup,
.ndo_netpoll_cleanup = br_netpoll_cleanup,
.ndo_poll_controller = br_poll_controller,
#endif
.ndo_add_slave = br_add_slave,
.ndo_del_slave = br_del_slave,
.ndo_fix_features = br_fix_features,
.ndo_fdb_add = br_fdb_add,
.ndo_fdb_del = br_fdb_delete,
.ndo_fdb_dump = br_fdb_dump,
.ndo_bridge_getlink = br_getlink,
.ndo_bridge_setlink = br_setlink,
.ndo_bridge_dellink = br_dellink,
.ndo_features_check = passthru_features_check,
};
static struct device_type br_type = {
.name = "bridge",
};
void br_dev_setup(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
eth_hw_addr_random(dev);
ether_setup(dev);
dev->netdev_ops = &br_netdev_ops;
dev->needs_free_netdev = true;
dev->ethtool_ops = &br_ethtool_ops;
SET_NETDEV_DEVTYPE(dev, &br_type);
dev->priv_flags = IFF_EBRIDGE | IFF_NO_QUEUE;
dev->features = COMMON_FEATURES | NETIF_F_LLTX | NETIF_F_NETNS_LOCAL |
NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
dev->hw_features = COMMON_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_STAG_TX;
dev->vlan_features = COMMON_FEATURES;
br->dev = dev;
spin_lock_init(&br->lock);
INIT_LIST_HEAD(&br->port_list);
INIT_HLIST_HEAD(&br->fdb_list);
spin_lock_init(&br->hash_lock);
br->bridge_id.prio[0] = 0x80;
br->bridge_id.prio[1] = 0x00;
ether_addr_copy(br->group_addr, eth_stp_addr);
br->stp_enabled = BR_NO_STP;
br->group_fwd_mask = BR_GROUPFWD_DEFAULT;
br->group_fwd_mask_required = BR_GROUPFWD_DEFAULT;
br->designated_root = br->bridge_id;
br->bridge_max_age = br->max_age = 20 * HZ;
br->bridge_hello_time = br->hello_time = 2 * HZ;
br->bridge_forward_delay = br->forward_delay = 15 * HZ;
br->bridge_ageing_time = br->ageing_time = BR_DEFAULT_AGEING_TIME;
dev->max_mtu = ETH_MAX_MTU;
br_netfilter_rtable_init(br);
br_stp_timer_init(br);
br_multicast_init(br);
INIT_DELAYED_WORK(&br->gc_work, br_fdb_cleanup);
}
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