/* * 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 _INET_HASHTABLES_H #define _INET_HASHTABLES_H #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* This is for all connections with a full identity, no wildcards. * One chain is dedicated to TIME_WAIT sockets. * I'll experiment with dynamic table growth later. */ struct inet_ehash_bucket { struct hlist_head chain; struct hlist_head twchain; }; /* There are a few simple rules, which allow for local port reuse by * an application. In essence: * * 1) Sockets bound to different interfaces may share a local port. * Failing that, goto test 2. * 2) If all sockets have sk->sk_reuse set, and none of them are in * TCP_LISTEN state, the port may be shared. * Failing that, goto test 3. * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local * address, and none of them are the same, the port may be * shared. * Failing this, the port cannot be shared. * * The interesting point, is test #2. This is what an FTP server does * all day. To optimize this case we use a specific flag bit defined * below. As we add sockets to a bind bucket list, we perform a * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) * As long as all sockets added to a bind bucket pass this test, * the flag bit will be set. * The resulting situation is that tcp_v[46]_verify_bind() can just check * for this flag bit, if it is set and the socket trying to bind has * sk->sk_reuse set, we don't even have to walk the owners list at all, * we return that it is ok to bind this socket to the requested local port. * * Sounds like a lot of work, but it is worth it. In a more naive * implementation (ie. current FreeBSD etc.) the entire list of ports * must be walked for each data port opened by an ftp server. Needless * to say, this does not scale at all. With a couple thousand FTP * users logged onto your box, isn't it nice to know that new data * ports are created in O(1) time? I thought so. ;-) -DaveM */ struct inet_bind_bucket { struct net *ib_net; unsigned short port; signed short fastreuse; struct hlist_node node; struct hlist_head owners; }; #define inet_bind_bucket_for_each(tb, node, head) \ hlist_for_each_entry(tb, node, head, node) struct inet_bind_hashbucket { spinlock_t lock; struct hlist_head chain; }; /* This is for listening sockets, thus all sockets which possess wildcards. */ #define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ struct inet_hashinfo { /* This is for sockets with full identity only. Sockets here will * always be without wildcards and will have the following invariant: * * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE * * TIME_WAIT sockets use a separate chain (twchain). */ struct inet_ehash_bucket *ehash; rwlock_t *ehash_locks; unsigned int ehash_size; unsigned int ehash_locks_mask; /* Ok, let's try this, I give up, we do need a local binding * TCP hash as well as the others for fast bind/connect. */ struct inet_bind_hashbucket *bhash; unsigned int bhash_size; /* Note : 4 bytes padding on 64 bit arches */ /* All sockets in TCP_LISTEN state will be in here. This is the only * table where wildcard'd TCP sockets can exist. Hash function here * is just local port number. */ struct hlist_head listening_hash[INET_LHTABLE_SIZE]; /* All the above members are written once at bootup and * never written again _or_ are predominantly read-access. * * Now align to a new cache line as all the following members * are often dirty. */ rwlock_t lhash_lock ____cacheline_aligned; atomic_t lhash_users; wait_queue_head_t lhash_wait; struct kmem_cache *bind_bucket_cachep; }; static inline struct inet_ehash_bucket *inet_ehash_bucket( struct inet_hashinfo *hashinfo, unsigned int hash) { return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)]; } static inline rwlock_t *inet_ehash_lockp( struct inet_hashinfo *hashinfo, unsigned int hash) { return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; } static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) { unsigned int i, size = 256; #if defined(CONFIG_PROVE_LOCKING) unsigned int nr_pcpus = 2; #else unsigned int nr_pcpus = num_possible_cpus(); #endif if (nr_pcpus >= 4) size = 512; if (nr_pcpus >= 8) size = 1024; if (nr_pcpus >= 16) size = 2048; if (nr_pcpus >= 32) size = 4096; if (sizeof(rwlock_t) != 0) { #ifdef CONFIG_NUMA if (size * sizeof(rwlock_t) > PAGE_SIZE) hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t)); else #endif hashinfo->ehash_locks = kmalloc(size * sizeof(rwlock_t), GFP_KERNEL); if (!hashinfo->ehash_locks) return ENOMEM; for (i = 0; i < size; i++) rwlock_init(&hashinfo->ehash_locks[i]); } hashinfo->ehash_locks_mask = size - 1; return 0; } static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) { if (hashinfo->ehash_locks) { #ifdef CONFIG_NUMA unsigned int size = (hashinfo->ehash_locks_mask + 1) * sizeof(rwlock_t); if (size > PAGE_SIZE) vfree(hashinfo->ehash_locks); else #endif kfree(hashinfo->ehash_locks); hashinfo->ehash_locks = NULL; } } extern struct inet_bind_bucket * inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, struct inet_bind_hashbucket *head, const unsigned short snum); extern void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb); static inline int inet_bhashfn(struct net *net, const __u16 lport, const int bhash_size) { return (lport + net_hash_mix(net)) & (bhash_size - 1); } extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, const unsigned short snum); /* These can have wildcards, don't try too hard. */ static inline int inet_lhashfn(struct net *net, const unsigned short num) { return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); } static inline int inet_sk_listen_hashfn(const struct sock *sk) { return inet_lhashfn(sock_net(sk), inet_sk(sk)->num); } /* Caller must disable local BH processing. */ extern void __inet_inherit_port(struct sock *sk, struct sock *child); extern void inet_put_port(struct sock *sk); extern void inet_listen_wlock(struct inet_hashinfo *hashinfo); /* * - We may sleep inside this lock. * - If sleeping is not required (or called from BH), * use plain read_(un)lock(&inet_hashinfo.lhash_lock). */ static inline void inet_listen_lock(struct inet_hashinfo *hashinfo) { /* read_lock synchronizes to candidates to writers */ read_lock(&hashinfo->lhash_lock); atomic_inc(&hashinfo->lhash_users); read_unlock(&hashinfo->lhash_lock); } static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo) { if (atomic_dec_and_test(&hashinfo->lhash_users)) wake_up(&hashinfo->lhash_wait); } extern void __inet_hash_nolisten(struct sock *sk); extern void inet_hash(struct sock *sk); extern void inet_unhash(struct sock *sk); extern struct sock *__inet_lookup_listener(struct net *net, struct inet_hashinfo *hashinfo, const __be32 daddr, const unsigned short hnum, const int dif); static inline struct sock *inet_lookup_listener(struct net *net, struct inet_hashinfo *hashinfo, __be32 daddr, __be16 dport, int dif) { return __inet_lookup_listener(net, hashinfo, daddr, ntohs(dport), dif); } /* Socket demux engine toys. */ /* What happens here is ugly; there's a pair of adjacent fields in struct inet_sock; __be16 dport followed by __u16 num. We want to search by pair, so we combine the keys into a single 32bit value and compare with 32bit value read from &...->dport. Let's at least make sure that it's not mixed with anything else... On 64bit targets we combine comparisons with pair of adjacent __be32 fields in the same way. */ typedef __u32 __bitwise __portpair; #ifdef __BIG_ENDIAN #define INET_COMBINED_PORTS(__sport, __dport) \ ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport))) #else /* __LITTLE_ENDIAN */ #define INET_COMBINED_PORTS(__sport, __dport) \ ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport))) #endif #if (BITS_PER_LONG == 64) typedef __u64 __bitwise __addrpair; #ifdef __BIG_ENDIAN #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const __addrpair __name = (__force __addrpair) ( \ (((__force __u64)(__be32)(__saddr)) << 32) | \ ((__force __u64)(__be32)(__daddr))); #else /* __LITTLE_ENDIAN */ #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const __addrpair __name = (__force __addrpair) ( \ (((__force __u64)(__be32)(__daddr)) << 32) | \ ((__force __u64)(__be32)(__saddr))); #endif /* __BIG_ENDIAN */ #define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) && sock_net((__sk)) == (__net) && \ ((*((__addrpair *)&(inet_sk(__sk)->daddr))) == (__cookie)) && \ ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) #define INET_TW_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) && sock_net((__sk)) == (__net) && \ ((*((__addrpair *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \ ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) #else /* 32-bit arch */ #define INET_ADDR_COOKIE(__name, __saddr, __daddr) #define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif) \ (((__sk)->sk_hash == (__hash)) && sock_net((__sk)) == (__net) && \ (inet_sk(__sk)->daddr == (__saddr)) && \ (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) #define INET_TW_MATCH(__sk, __net, __hash,__cookie, __saddr, __daddr, __ports, __dif) \ (((__sk)->sk_hash == (__hash)) && sock_net((__sk)) == (__net) && \ (inet_twsk(__sk)->tw_daddr == (__saddr)) && \ (inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \ ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) #endif /* 64-bit arch */ /* * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need * not check it for lookups anymore, thanks Alexey. -DaveM * * Local BH must be disabled here. */ extern struct sock * __inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const u16 hnum, const int dif); static inline struct sock * inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const __be16 dport, const int dif) { return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); } static inline struct sock *__inet_lookup(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const __be16 dport, const int dif) { u16 hnum = ntohs(dport); struct sock *sk = __inet_lookup_established(net, hashinfo, saddr, sport, daddr, hnum, dif); return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif); } static inline struct sock *inet_lookup(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const __be16 dport, const int dif) { struct sock *sk; local_bh_disable(); sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif); local_bh_enable(); return sk; } static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, struct sk_buff *skb, const __be16 sport, const __be16 dport) { struct sock *sk; const struct iphdr *iph = ip_hdr(skb); if (unlikely(sk = skb_steal_sock(skb))) return sk; #ifdef CONFIG_AVM_PA sk = __inet_lookup(dev_net(skb->dst->dev), hashinfo, iph->saddr, sport, iph->daddr, dport, inet_iif(skb)); if (sk) avm_pa_add_local_session(skb, sk); return sk; #else return __inet_lookup(dev_net(skb->dst->dev), hashinfo, iph->saddr, sport, iph->daddr, dport, inet_iif(skb)); #endif } extern int __inet_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk, u32 port_offset, int (*check_established)(struct inet_timewait_death_row *, struct sock *, __u16, struct inet_timewait_sock **), void (*hash)(struct sock *sk)); extern int inet_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk); #endif /* _INET_HASHTABLES_H */