393 lines
13 KiB
C
393 lines
13 KiB
C
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/*
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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/interrupt.h>
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#include <linux/ip.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/inet_sock.h>
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#include <net/sock.h>
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#include <net/route.h>
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#include <net/tcp_states.h>
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#include <net/netns/hash.h>
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#include <linux/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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* The 'e' prefix stands for Establish, but we really put all sockets
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* but LISTEN ones.
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*/
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struct inet_ehash_bucket {
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struct hlist_nulls_head chain;
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};
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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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possible_net_t ib_net;
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unsigned short port;
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signed char fastreuse;
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signed char fastreuseport;
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kuid_t fastuid;
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int num_owners;
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struct hlist_node node;
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struct hlist_head owners;
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};
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static inline struct net *ib_net(struct inet_bind_bucket *ib)
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{
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return read_pnet(&ib->ib_net);
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}
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#define inet_bind_bucket_for_each(tb, head) \
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hlist_for_each_entry(tb, 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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/* Sockets can be hashed in established or listening table.
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* We must use different 'nulls' end-of-chain value for all hash buckets :
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* A socket might transition from ESTABLISH to LISTEN state without
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* RCU grace period. A lookup in ehash table needs to handle this case.
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*/
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#define LISTENING_NULLS_BASE (1U << 29)
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struct inet_listen_hashbucket {
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spinlock_t lock;
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union {
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struct hlist_head head;
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struct hlist_nulls_head nulls_head;
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};
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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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*/
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struct inet_ehash_bucket *ehash;
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spinlock_t *ehash_locks;
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unsigned int ehash_mask;
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unsigned int ehash_locks_mask;
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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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unsigned int bhash_size;
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/* 4 bytes hole on 64 bit */
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struct kmem_cache *bind_bucket_cachep;
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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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* might be often dirty.
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*/
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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 inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE]
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____cacheline_aligned_in_smp;
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};
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static inline struct inet_ehash_bucket *inet_ehash_bucket(
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struct inet_hashinfo *hashinfo,
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unsigned int hash)
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{
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return &hashinfo->ehash[hash & hashinfo->ehash_mask];
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}
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static inline spinlock_t *inet_ehash_lockp(
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struct inet_hashinfo *hashinfo,
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unsigned int hash)
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{
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return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
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}
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int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);
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static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
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{
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kvfree(hashinfo->ehash_locks);
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hashinfo->ehash_locks = NULL;
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}
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struct inet_bind_bucket *
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inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
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struct inet_bind_hashbucket *head,
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const unsigned short snum);
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void inet_bind_bucket_destroy(struct kmem_cache *cachep,
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struct inet_bind_bucket *tb);
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static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
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const u32 bhash_size)
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{
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return (lport + net_hash_mix(net)) & (bhash_size - 1);
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}
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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 u32 inet_lhashfn(const struct net *net, const unsigned short num)
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{
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return (num + net_hash_mix(net)) & (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(sock_net(sk), inet_sk(sk)->inet_num);
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}
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/* Caller must disable local BH processing. */
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int __inet_inherit_port(const struct sock *sk, struct sock *child);
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void inet_put_port(struct sock *sk);
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void inet_hashinfo_init(struct inet_hashinfo *h);
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bool inet_ehash_insert(struct sock *sk, struct sock *osk);
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bool inet_ehash_nolisten(struct sock *sk, struct sock *osk);
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int __inet_hash(struct sock *sk, struct sock *osk,
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int (*saddr_same)(const struct sock *sk1,
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const struct sock *sk2,
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bool match_wildcard));
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int inet_hash(struct sock *sk);
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void inet_unhash(struct sock *sk);
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struct sock *__inet_lookup_listener(struct net *net,
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struct inet_hashinfo *hashinfo,
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struct sk_buff *skb, int doff,
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const __be32 saddr, const __be16 sport,
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const __be32 daddr,
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const unsigned short hnum,
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const int dif);
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static inline struct sock *inet_lookup_listener(struct net *net,
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struct inet_hashinfo *hashinfo,
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struct sk_buff *skb, int doff,
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__be32 saddr, __be16 sport,
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__be32 daddr, __be16 dport, int dif)
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{
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return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
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daddr, ntohs(dport), dif);
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}
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/* Socket demux engine toys. */
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/* What happens here is ugly; there's a pair of adjacent fields in
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struct inet_sock; __be16 dport followed by __u16 num. We want to
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search by pair, so we combine the keys into a single 32bit value
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and compare with 32bit value read from &...->dport. Let's at least
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make sure that it's not mixed with anything else...
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On 64bit targets we combine comparisons with pair of adjacent __be32
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fields in the same way.
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*/
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#ifdef __BIG_ENDIAN
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#define INET_COMBINED_PORTS(__sport, __dport) \
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((__force __portpair)(((__force __u32)(__be16)(__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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((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__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 __addrpair __name = (__force __addrpair) ( \
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(((__force __u64)(__be32)(__saddr)) << 32) | \
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((__force __u64)(__be32)(__daddr)))
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#else /* __LITTLE_ENDIAN */
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#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
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const __addrpair __name = (__force __addrpair) ( \
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(((__force __u64)(__be32)(__daddr)) << 32) | \
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((__force __u64)(__be32)(__saddr)))
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#endif /* __BIG_ENDIAN */
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#define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \
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(((__sk)->sk_portpair == (__ports)) && \
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((__sk)->sk_addrpair == (__cookie)) && \
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(!(__sk)->sk_bound_dev_if || \
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((__sk)->sk_bound_dev_if == (__dif))) && \
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net_eq(sock_net(__sk), (__net)))
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#else /* 32-bit arch */
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#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
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const int __name __deprecated __attribute__((unused))
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#define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \
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(((__sk)->sk_portpair == (__ports)) && \
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((__sk)->sk_daddr == (__saddr)) && \
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((__sk)->sk_rcv_saddr == (__daddr)) && \
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(!(__sk)->sk_bound_dev_if || \
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((__sk)->sk_bound_dev_if == (__dif))) && \
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net_eq(sock_net(__sk), (__net)))
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#endif /* 64-bit arch */
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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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struct sock *__inet_lookup_established(struct net *net,
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struct inet_hashinfo *hashinfo,
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const __be32 saddr, const __be16 sport,
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const __be32 daddr, const u16 hnum,
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const int dif);
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static inline struct sock *
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inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
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const __be32 saddr, const __be16 sport,
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const __be32 daddr, const __be16 dport,
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const int dif)
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{
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return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
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ntohs(dport), dif);
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}
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static inline struct sock *__inet_lookup(struct net *net,
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struct inet_hashinfo *hashinfo,
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struct sk_buff *skb, int doff,
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const __be32 saddr, const __be16 sport,
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const __be32 daddr, const __be16 dport,
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const int dif,
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bool *refcounted)
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{
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u16 hnum = ntohs(dport);
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struct sock *sk;
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sk = __inet_lookup_established(net, hashinfo, saddr, sport,
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daddr, hnum, dif);
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*refcounted = true;
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if (sk)
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return sk;
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*refcounted = false;
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return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
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sport, daddr, hnum, dif);
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}
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static inline struct sock *inet_lookup(struct net *net,
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struct inet_hashinfo *hashinfo,
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struct sk_buff *skb, int doff,
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const __be32 saddr, const __be16 sport,
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const __be32 daddr, const __be16 dport,
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const int dif)
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{
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struct sock *sk;
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bool refcounted;
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sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
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dport, dif, &refcounted);
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if (sk && !refcounted && !atomic_inc_not_zero(&sk->sk_refcnt))
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sk = NULL;
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return sk;
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}
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static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
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struct sk_buff *skb,
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int doff,
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const __be16 sport,
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const __be16 dport,
|
||
|
|
bool *refcounted)
|
||
|
|
{
|
||
|
|
struct sock *sk = skb_steal_sock(skb);
|
||
|
|
const struct iphdr *iph = ip_hdr(skb);
|
||
|
|
|
||
|
|
*refcounted = true;
|
||
|
|
if (sk)
|
||
|
|
return sk;
|
||
|
|
|
||
|
|
return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
|
||
|
|
doff, iph->saddr, sport,
|
||
|
|
iph->daddr, dport, inet_iif(skb),
|
||
|
|
refcounted);
|
||
|
|
}
|
||
|
|
|
||
|
|
u32 sk_ehashfn(const struct sock *sk);
|
||
|
|
u32 inet6_ehashfn(const struct net *net,
|
||
|
|
const struct in6_addr *laddr, const u16 lport,
|
||
|
|
const struct in6_addr *faddr, const __be16 fport);
|
||
|
|
|
||
|
|
static inline void sk_daddr_set(struct sock *sk, __be32 addr)
|
||
|
|
{
|
||
|
|
sk->sk_daddr = addr; /* alias of inet_daddr */
|
||
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
||
|
|
ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
|
||
|
|
{
|
||
|
|
sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
|
||
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
||
|
|
ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
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 **));
|
||
|
|
|
||
|
|
int inet_hash_connect(struct inet_timewait_death_row *death_row,
|
||
|
|
struct sock *sk);
|
||
|
|
#endif /* _INET_HASHTABLES_H */
|