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https://github.com/torvalds/linux
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08dcdbf6a7
It looks like its possible to open thousands of TCP IPv6 sessions on a server, all landing in a single slot of TCP hash table. Incoming packets have to lookup sockets in a very long list. We should hash all bits from foreign IPv6 addresses, using a salt and hash mix, not a simple XOR. inet6_ehashfn() can also separately use the ports, instead of xoring them. Reported-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Authors: Lotsa people, from code originally in tcp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _INET6_HASHTABLES_H
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#define _INET6_HASHTABLES_H
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#if IS_ENABLED(CONFIG_IPV6)
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#include <linux/in6.h>
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#include <linux/ipv6.h>
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#include <linux/types.h>
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#include <linux/jhash.h>
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#include <net/inet_sock.h>
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#include <net/ipv6.h>
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#include <net/netns/hash.h>
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struct inet_hashinfo;
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static inline unsigned int inet6_ehashfn(struct net *net,
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const struct in6_addr *laddr, const u16 lport,
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const struct in6_addr *faddr, const __be16 fport)
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{
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u32 ports = (((u32)lport) << 16) | (__force u32)fport;
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return jhash_3words((__force u32)laddr->s6_addr32[3],
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ipv6_addr_jhash(faddr),
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ports,
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inet_ehash_secret + net_hash_mix(net));
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}
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static inline int inet6_sk_ehashfn(const struct sock *sk)
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{
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const struct inet_sock *inet = inet_sk(sk);
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const struct ipv6_pinfo *np = inet6_sk(sk);
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const struct in6_addr *laddr = &np->rcv_saddr;
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const struct in6_addr *faddr = &np->daddr;
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const __u16 lport = inet->inet_num;
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const __be16 fport = inet->inet_dport;
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struct net *net = sock_net(sk);
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return inet6_ehashfn(net, laddr, lport, faddr, fport);
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}
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extern int __inet6_hash(struct sock *sk, struct inet_timewait_sock *twp);
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/*
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* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
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* we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
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*
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* The sockhash lock must be held as a reader here.
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*/
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extern struct sock *__inet6_lookup_established(struct net *net,
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struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr,
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const __be16 sport,
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const struct in6_addr *daddr,
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const u16 hnum,
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const int dif);
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extern struct sock *inet6_lookup_listener(struct net *net,
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struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr,
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const __be16 sport,
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const struct in6_addr *daddr,
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const unsigned short hnum,
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const int dif);
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static inline struct sock *__inet6_lookup(struct net *net,
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struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr,
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const __be16 sport,
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const struct in6_addr *daddr,
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const u16 hnum,
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const int dif)
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{
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struct sock *sk = __inet6_lookup_established(net, hashinfo, saddr,
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sport, daddr, hnum, dif);
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if (sk)
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return sk;
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return inet6_lookup_listener(net, hashinfo, saddr, sport,
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daddr, hnum, dif);
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}
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static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
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struct sk_buff *skb,
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const __be16 sport,
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const __be16 dport)
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{
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struct sock *sk = skb_steal_sock(skb);
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if (sk)
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return sk;
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return __inet6_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
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&ipv6_hdr(skb)->saddr, sport,
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&ipv6_hdr(skb)->daddr, ntohs(dport),
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inet6_iif(skb));
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}
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extern struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr, const __be16 sport,
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const struct in6_addr *daddr, const __be16 dport,
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const int dif);
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#endif /* IS_ENABLED(CONFIG_IPV6) */
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#endif /* _INET6_HASHTABLES_H */
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