7d9e5f4221
For tx path, in most cases, we still have to take refcnt on the dst cause the caller is caching the dst somewhere. But it still is beneficial to make use of RT6_LOOKUP_F_DST_NOREF flag while doing the route lookup. It is cause this flag prevents manipulating refcnt on net->ipv6.ip6_null_entry when doing fib6_rule_lookup() to traverse each routing table. The null_entry is a shared object and constant updates on it cause false sharing. We converted the current major lookup function ip6_route_output_flags() to make use of RT6_LOOKUP_F_DST_NOREF. Together with the change in the rx path, we see noticable performance boost: I ran synflood tests between 2 hosts under the same switch. Both hosts have 20G mlx NIC, and 8 tx/rx queues. Sender sends pure SYN flood with random src IPs and ports using trafgen. Receiver has a simple TCP listener on the target port. Both hosts have multiple custom rules: - For incoming packets, only local table is traversed. - For outgoing packets, 3 tables are traversed to find the route. The packet processing rate on the receiver is as follows: - Before the fix: 3.78Mpps - After the fix: 5.50Mpps Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
217 lines
5 KiB
C
217 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/l3mdev/l3mdev.c - L3 master device implementation
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* Copyright (c) 2015 Cumulus Networks
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* Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
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*/
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#include <linux/netdevice.h>
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#include <net/fib_rules.h>
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#include <net/l3mdev.h>
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/**
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* l3mdev_master_ifindex - get index of L3 master device
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* @dev: targeted interface
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*/
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int l3mdev_master_ifindex_rcu(const struct net_device *dev)
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{
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int ifindex = 0;
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if (!dev)
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return 0;
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if (netif_is_l3_master(dev)) {
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ifindex = dev->ifindex;
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} else if (netif_is_l3_slave(dev)) {
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struct net_device *master;
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struct net_device *_dev = (struct net_device *)dev;
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/* netdev_master_upper_dev_get_rcu calls
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* list_first_or_null_rcu to walk the upper dev list.
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* list_first_or_null_rcu does not handle a const arg. We aren't
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* making changes, just want the master device from that list so
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* typecast to remove the const
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*/
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master = netdev_master_upper_dev_get_rcu(_dev);
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if (master)
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ifindex = master->ifindex;
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}
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return ifindex;
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}
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EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
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/**
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* l3mdev_master_upper_ifindex_by_index - get index of upper l3 master
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* device
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* @net: network namespace for device index lookup
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* @ifindex: targeted interface
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*/
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int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
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{
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struct net_device *dev;
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dev = dev_get_by_index_rcu(net, ifindex);
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while (dev && !netif_is_l3_master(dev))
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dev = netdev_master_upper_dev_get(dev);
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return dev ? dev->ifindex : 0;
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}
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EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
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/**
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* l3mdev_fib_table - get FIB table id associated with an L3
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* master interface
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* @dev: targeted interface
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*/
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u32 l3mdev_fib_table_rcu(const struct net_device *dev)
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{
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u32 tb_id = 0;
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if (!dev)
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return 0;
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if (netif_is_l3_master(dev)) {
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if (dev->l3mdev_ops->l3mdev_fib_table)
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tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
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} else if (netif_is_l3_slave(dev)) {
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/* Users of netdev_master_upper_dev_get_rcu need non-const,
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* but current inet_*type functions take a const
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*/
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struct net_device *_dev = (struct net_device *) dev;
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const struct net_device *master;
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master = netdev_master_upper_dev_get_rcu(_dev);
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if (master &&
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master->l3mdev_ops->l3mdev_fib_table)
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tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
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}
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return tb_id;
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}
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EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
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u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
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{
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struct net_device *dev;
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u32 tb_id = 0;
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if (!ifindex)
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return 0;
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rcu_read_lock();
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dev = dev_get_by_index_rcu(net, ifindex);
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if (dev)
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tb_id = l3mdev_fib_table_rcu(dev);
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rcu_read_unlock();
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return tb_id;
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}
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EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
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/**
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* l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
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* local and multicast addresses
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* @net: network namespace for device index lookup
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* @fl6: IPv6 flow struct for lookup
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* This function does not hold refcnt on the returned dst.
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* Caller must hold rcu_read_lock().
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*/
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struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
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struct flowi6 *fl6)
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{
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struct dst_entry *dst = NULL;
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struct net_device *dev;
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WARN_ON_ONCE(!rcu_read_lock_held());
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if (fl6->flowi6_oif) {
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dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
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if (dev && netif_is_l3_slave(dev))
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dev = netdev_master_upper_dev_get_rcu(dev);
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if (dev && netif_is_l3_master(dev) &&
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dev->l3mdev_ops->l3mdev_link_scope_lookup)
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dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);
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}
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return dst;
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}
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EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);
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/**
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* l3mdev_fib_rule_match - Determine if flowi references an
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* L3 master device
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* @net: network namespace for device index lookup
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* @fl: flow struct
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*/
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int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
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struct fib_lookup_arg *arg)
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{
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struct net_device *dev;
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int rc = 0;
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rcu_read_lock();
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dev = dev_get_by_index_rcu(net, fl->flowi_oif);
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if (dev && netif_is_l3_master(dev) &&
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dev->l3mdev_ops->l3mdev_fib_table) {
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arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
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rc = 1;
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goto out;
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}
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dev = dev_get_by_index_rcu(net, fl->flowi_iif);
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if (dev && netif_is_l3_master(dev) &&
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dev->l3mdev_ops->l3mdev_fib_table) {
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arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
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rc = 1;
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goto out;
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}
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out:
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rcu_read_unlock();
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return rc;
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}
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void l3mdev_update_flow(struct net *net, struct flowi *fl)
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{
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struct net_device *dev;
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int ifindex;
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rcu_read_lock();
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if (fl->flowi_oif) {
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dev = dev_get_by_index_rcu(net, fl->flowi_oif);
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if (dev) {
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ifindex = l3mdev_master_ifindex_rcu(dev);
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if (ifindex) {
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fl->flowi_oif = ifindex;
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fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
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goto out;
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}
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}
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}
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if (fl->flowi_iif) {
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dev = dev_get_by_index_rcu(net, fl->flowi_iif);
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if (dev) {
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ifindex = l3mdev_master_ifindex_rcu(dev);
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if (ifindex) {
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fl->flowi_iif = ifindex;
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fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
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}
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}
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}
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out:
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rcu_read_unlock();
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}
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EXPORT_SYMBOL_GPL(l3mdev_update_flow);
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