![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
422 lines
13 KiB
C
422 lines
13 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 _INET_HASHTABLES_H
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#define _INET_HASHTABLES_H
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#include <linux/config.h>
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#include <linux/interrupt.h>
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#include <linux/ipv6.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/socket.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/wait.h>
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#include <net/inet_connection_sock.h>
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#include <net/sock.h>
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#include <net/tcp_states.h>
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#include <asm/atomic.h>
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#include <asm/byteorder.h>
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/* This is for all connections with a full identity, no wildcards.
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* New scheme, half the table is for TIME_WAIT, the other half is
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* for the rest. I'll experiment with dynamic table growth later.
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*/
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struct inet_ehash_bucket {
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rwlock_t lock;
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struct hlist_head chain;
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} __attribute__((__aligned__(8)));
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/* There are a few simple rules, which allow for local port reuse by
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* an application. In essence:
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*
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* 1) Sockets bound to different interfaces may share a local port.
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* Failing that, goto test 2.
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* 2) If all sockets have sk->sk_reuse set, and none of them are in
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* TCP_LISTEN state, the port may be shared.
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* Failing that, goto test 3.
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* 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
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* address, and none of them are the same, the port may be
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* shared.
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* Failing this, the port cannot be shared.
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*
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* The interesting point, is test #2. This is what an FTP server does
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* all day. To optimize this case we use a specific flag bit defined
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* below. As we add sockets to a bind bucket list, we perform a
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* check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
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* As long as all sockets added to a bind bucket pass this test,
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* the flag bit will be set.
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* The resulting situation is that tcp_v[46]_verify_bind() can just check
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* for this flag bit, if it is set and the socket trying to bind has
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* sk->sk_reuse set, we don't even have to walk the owners list at all,
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* we return that it is ok to bind this socket to the requested local port.
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*
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* Sounds like a lot of work, but it is worth it. In a more naive
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* implementation (ie. current FreeBSD etc.) the entire list of ports
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* must be walked for each data port opened by an ftp server. Needless
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* to say, this does not scale at all. With a couple thousand FTP
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* users logged onto your box, isn't it nice to know that new data
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* ports are created in O(1) time? I thought so. ;-) -DaveM
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*/
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struct inet_bind_bucket {
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unsigned short port;
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signed short fastreuse;
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struct hlist_node node;
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struct hlist_head owners;
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};
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#define inet_bind_bucket_for_each(tb, node, head) \
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hlist_for_each_entry(tb, node, head, node)
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struct inet_bind_hashbucket {
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spinlock_t lock;
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struct hlist_head chain;
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};
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/* This is for listening sockets, thus all sockets which possess wildcards. */
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#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
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struct inet_hashinfo {
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/* This is for sockets with full identity only. Sockets here will
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* always be without wildcards and will have the following invariant:
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*
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* TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
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*
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* First half of the table is for sockets not in TIME_WAIT, second half
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* is for TIME_WAIT sockets only.
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*/
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struct inet_ehash_bucket *ehash;
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/* Ok, let's try this, I give up, we do need a local binding
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* TCP hash as well as the others for fast bind/connect.
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*/
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struct inet_bind_hashbucket *bhash;
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int bhash_size;
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int ehash_size;
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/* All sockets in TCP_LISTEN state will be in here. This is the only
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* table where wildcard'd TCP sockets can exist. Hash function here
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* is just local port number.
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*/
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struct hlist_head listening_hash[INET_LHTABLE_SIZE];
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/* All the above members are written once at bootup and
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* never written again _or_ are predominantly read-access.
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*
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* Now align to a new cache line as all the following members
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* are often dirty.
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*/
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rwlock_t lhash_lock ____cacheline_aligned;
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atomic_t lhash_users;
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wait_queue_head_t lhash_wait;
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spinlock_t portalloc_lock;
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kmem_cache_t *bind_bucket_cachep;
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int port_rover;
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};
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static inline int inet_ehashfn(const __u32 laddr, const __u16 lport,
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const __u32 faddr, const __u16 fport,
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const int ehash_size)
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{
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int h = (laddr ^ lport) ^ (faddr ^ fport);
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h ^= h >> 16;
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h ^= h >> 8;
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return h & (ehash_size - 1);
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}
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static inline int inet_sk_ehashfn(const struct sock *sk, const int ehash_size)
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{
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const struct inet_sock *inet = inet_sk(sk);
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const __u32 laddr = inet->rcv_saddr;
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const __u16 lport = inet->num;
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const __u32 faddr = inet->daddr;
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const __u16 fport = inet->dport;
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return inet_ehashfn(laddr, lport, faddr, fport, ehash_size);
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}
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extern struct inet_bind_bucket *
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inet_bind_bucket_create(kmem_cache_t *cachep,
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struct inet_bind_hashbucket *head,
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const unsigned short snum);
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extern void inet_bind_bucket_destroy(kmem_cache_t *cachep,
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struct inet_bind_bucket *tb);
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static inline int inet_bhashfn(const __u16 lport, const int bhash_size)
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{
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return lport & (bhash_size - 1);
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}
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extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
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const unsigned short snum);
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/* These can have wildcards, don't try too hard. */
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static inline int inet_lhashfn(const unsigned short num)
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{
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return num & (INET_LHTABLE_SIZE - 1);
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}
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static inline int inet_sk_listen_hashfn(const struct sock *sk)
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{
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return inet_lhashfn(inet_sk(sk)->num);
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}
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/* Caller must disable local BH processing. */
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static inline void __inet_inherit_port(struct inet_hashinfo *table,
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struct sock *sk, struct sock *child)
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{
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const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size);
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struct inet_bind_hashbucket *head = &table->bhash[bhash];
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struct inet_bind_bucket *tb;
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spin_lock(&head->lock);
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tb = inet_csk(sk)->icsk_bind_hash;
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sk_add_bind_node(child, &tb->owners);
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inet_csk(child)->icsk_bind_hash = tb;
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spin_unlock(&head->lock);
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}
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static inline void inet_inherit_port(struct inet_hashinfo *table,
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struct sock *sk, struct sock *child)
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{
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local_bh_disable();
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__inet_inherit_port(table, sk, child);
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local_bh_enable();
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}
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extern void inet_put_port(struct inet_hashinfo *table, struct sock *sk);
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extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);
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/*
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* - We may sleep inside this lock.
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* - If sleeping is not required (or called from BH),
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* use plain read_(un)lock(&inet_hashinfo.lhash_lock).
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*/
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static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
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{
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/* read_lock synchronizes to candidates to writers */
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read_lock(&hashinfo->lhash_lock);
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atomic_inc(&hashinfo->lhash_users);
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read_unlock(&hashinfo->lhash_lock);
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}
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static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
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{
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if (atomic_dec_and_test(&hashinfo->lhash_users))
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wake_up(&hashinfo->lhash_wait);
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}
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static inline void __inet_hash(struct inet_hashinfo *hashinfo,
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struct sock *sk, const int listen_possible)
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{
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struct hlist_head *list;
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rwlock_t *lock;
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BUG_TRAP(sk_unhashed(sk));
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if (listen_possible && sk->sk_state == TCP_LISTEN) {
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list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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lock = &hashinfo->lhash_lock;
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inet_listen_wlock(hashinfo);
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} else {
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sk->sk_hashent = inet_sk_ehashfn(sk, hashinfo->ehash_size);
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list = &hashinfo->ehash[sk->sk_hashent].chain;
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lock = &hashinfo->ehash[sk->sk_hashent].lock;
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write_lock(lock);
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}
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__sk_add_node(sk, list);
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sock_prot_inc_use(sk->sk_prot);
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write_unlock(lock);
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if (listen_possible && sk->sk_state == TCP_LISTEN)
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wake_up(&hashinfo->lhash_wait);
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}
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static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
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{
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if (sk->sk_state != TCP_CLOSE) {
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local_bh_disable();
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__inet_hash(hashinfo, sk, 1);
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local_bh_enable();
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}
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}
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static inline void inet_unhash(struct inet_hashinfo *hashinfo, struct sock *sk)
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{
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rwlock_t *lock;
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if (sk_unhashed(sk))
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goto out;
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if (sk->sk_state == TCP_LISTEN) {
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local_bh_disable();
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inet_listen_wlock(hashinfo);
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lock = &hashinfo->lhash_lock;
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} else {
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struct inet_ehash_bucket *head = &hashinfo->ehash[sk->sk_hashent];
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lock = &head->lock;
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write_lock_bh(&head->lock);
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}
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if (__sk_del_node_init(sk))
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sock_prot_dec_use(sk->sk_prot);
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write_unlock_bh(lock);
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out:
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if (sk->sk_state == TCP_LISTEN)
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wake_up(&hashinfo->lhash_wait);
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}
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extern struct sock *__inet_lookup_listener(const struct hlist_head *head,
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const u32 daddr,
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const unsigned short hnum,
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const int dif);
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/* Optimize the common listener case. */
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static inline struct sock *
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inet_lookup_listener(struct inet_hashinfo *hashinfo,
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const u32 daddr,
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const unsigned short hnum, const int dif)
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{
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struct sock *sk = NULL;
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const struct hlist_head *head;
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read_lock(&hashinfo->lhash_lock);
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head = &hashinfo->listening_hash[inet_lhashfn(hnum)];
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if (!hlist_empty(head)) {
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const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
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if (inet->num == hnum && !sk->sk_node.next &&
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(!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
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(sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
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!sk->sk_bound_dev_if)
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goto sherry_cache;
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sk = __inet_lookup_listener(head, daddr, hnum, dif);
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}
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if (sk) {
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sherry_cache:
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sock_hold(sk);
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}
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read_unlock(&hashinfo->lhash_lock);
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return sk;
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}
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/* Socket demux engine toys. */
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#ifdef __BIG_ENDIAN
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#define INET_COMBINED_PORTS(__sport, __dport) \
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(((__u32)(__sport) << 16) | (__u32)(__dport))
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#else /* __LITTLE_ENDIAN */
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#define INET_COMBINED_PORTS(__sport, __dport) \
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(((__u32)(__dport) << 16) | (__u32)(__sport))
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#endif
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#if (BITS_PER_LONG == 64)
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#ifdef __BIG_ENDIAN
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#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
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const __u64 __name = (((__u64)(__saddr)) << 32) | ((__u64)(__daddr));
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#else /* __LITTLE_ENDIAN */
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#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
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const __u64 __name = (((__u64)(__daddr)) << 32) | ((__u64)(__saddr));
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#endif /* __BIG_ENDIAN */
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#define INET_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
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(((*((__u64 *)&(inet_sk(__sk)->daddr))) == (__cookie)) && \
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((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \
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(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
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#define INET_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
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(((*((__u64 *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \
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((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \
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(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
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#else /* 32-bit arch */
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#define INET_ADDR_COOKIE(__name, __saddr, __daddr)
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#define INET_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif) \
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((inet_sk(__sk)->daddr == (__saddr)) && \
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(inet_sk(__sk)->rcv_saddr == (__daddr)) && \
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((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \
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(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
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#define INET_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif) \
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((inet_twsk(__sk)->tw_daddr == (__saddr)) && \
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(inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \
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((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \
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(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
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#endif /* 64-bit arch */
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/*
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* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
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* not check it for lookups anymore, thanks Alexey. -DaveM
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*
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* Local BH must be disabled here.
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*/
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static inline struct sock *
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__inet_lookup_established(struct inet_hashinfo *hashinfo,
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const u32 saddr, const u16 sport,
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const u32 daddr, const u16 hnum,
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const int dif)
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{
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INET_ADDR_COOKIE(acookie, saddr, daddr)
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const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
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struct sock *sk;
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const struct hlist_node *node;
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/* Optimize here for direct hit, only listening connections can
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* have wildcards anyways.
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*/
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const int hash = inet_ehashfn(daddr, hnum, saddr, sport, hashinfo->ehash_size);
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struct inet_ehash_bucket *head = &hashinfo->ehash[hash];
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read_lock(&head->lock);
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sk_for_each(sk, node, &head->chain) {
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if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif))
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goto hit; /* You sunk my battleship! */
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}
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/* Must check for a TIME_WAIT'er before going to listener hash. */
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sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
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if (INET_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
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goto hit;
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}
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sk = NULL;
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out:
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read_unlock(&head->lock);
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return sk;
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hit:
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sock_hold(sk);
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goto out;
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}
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static inline struct sock *__inet_lookup(struct inet_hashinfo *hashinfo,
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const u32 saddr, const u16 sport,
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const u32 daddr, const u16 hnum,
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const int dif)
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{
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struct sock *sk = __inet_lookup_established(hashinfo, saddr, sport, daddr,
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hnum, dif);
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return sk ? : inet_lookup_listener(hashinfo, daddr, hnum, dif);
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}
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static inline struct sock *inet_lookup(struct inet_hashinfo *hashinfo,
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const u32 saddr, const u16 sport,
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const u32 daddr, const u16 dport,
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const int dif)
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{
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struct sock *sk;
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local_bh_disable();
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sk = __inet_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
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local_bh_enable();
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return sk;
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}
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#endif /* _INET_HASHTABLES_H */
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