kernel-ark/include/net/inet6_hashtables.h
Eric Dumazet 3b24d854cb tcp/dccp: do not touch listener sk_refcnt under synflood
When a SYNFLOOD targets a non SO_REUSEPORT listener, multiple
cpus contend on sk->sk_refcnt and sk->sk_wmem_alloc changes.

By letting listeners use SOCK_RCU_FREE infrastructure,
we can relax TCP_LISTEN lookup rules and avoid touching sk_refcnt

Note that we still use SLAB_DESTROY_BY_RCU rules for other sockets,
only listeners are impacted by this change.

Peak performance under SYNFLOOD is increased by ~33% :

On my test machine, I could process 3.2 Mpps instead of 2.4 Mpps

Most consuming functions are now skb_set_owner_w() and sock_wfree()
contending on sk->sk_wmem_alloc when cooking SYNACK and freeing them.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-04 22:11:20 -04:00

120 lines
3.5 KiB
C

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Authors: Lotsa people, from code originally in tcp
*
* 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.
*/
#ifndef _INET6_HASHTABLES_H
#define _INET6_HASHTABLES_H
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/types.h>
#include <linux/jhash.h>
#include <net/inet_sock.h>
#include <net/ipv6.h>
#include <net/netns/hash.h>
struct inet_hashinfo;
static inline unsigned int __inet6_ehashfn(const u32 lhash,
const u16 lport,
const u32 fhash,
const __be16 fport,
const u32 initval)
{
const u32 ports = (((u32)lport) << 16) | (__force u32)fport;
return jhash_3words(lhash, fhash, ports, initval);
}
/*
* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
* we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
*
* The sockhash lock must be held as a reader here.
*/
struct sock *__inet6_lookup_established(struct net *net,
struct inet_hashinfo *hashinfo,
const struct in6_addr *saddr,
const __be16 sport,
const struct in6_addr *daddr,
const u16 hnum, const int dif);
struct sock *inet6_lookup_listener(struct net *net,
struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
const struct in6_addr *saddr,
const __be16 sport,
const struct in6_addr *daddr,
const unsigned short hnum, const int dif);
static inline struct sock *__inet6_lookup(struct net *net,
struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
const struct in6_addr *saddr,
const __be16 sport,
const struct in6_addr *daddr,
const u16 hnum,
const int dif,
bool *refcounted)
{
struct sock *sk = __inet6_lookup_established(net, hashinfo, saddr,
sport, daddr, hnum, dif);
*refcounted = true;
if (sk)
return sk;
*refcounted = false;
return inet6_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
daddr, hnum, dif);
}
static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
const __be16 sport,
const __be16 dport,
int iif,
bool *refcounted)
{
struct sock *sk = skb_steal_sock(skb);
*refcounted = true;
if (sk)
return sk;
return __inet6_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
doff, &ipv6_hdr(skb)->saddr, sport,
&ipv6_hdr(skb)->daddr, ntohs(dport),
iif, refcounted);
}
struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
const struct in6_addr *saddr, const __be16 sport,
const struct in6_addr *daddr, const __be16 dport,
const int dif);
int inet6_hash(struct sock *sk);
#endif /* IS_ENABLED(CONFIG_IPV6) */
#define INET6_MATCH(__sk, __net, __saddr, __daddr, __ports, __dif) \
(((__sk)->sk_portpair == (__ports)) && \
((__sk)->sk_family == AF_INET6) && \
ipv6_addr_equal(&(__sk)->sk_v6_daddr, (__saddr)) && \
ipv6_addr_equal(&(__sk)->sk_v6_rcv_saddr, (__daddr)) && \
(!(__sk)->sk_bound_dev_if || \
((__sk)->sk_bound_dev_if == (__dif))) && \
net_eq(sock_net(__sk), (__net)))
#endif /* _INET6_HASHTABLES_H */