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435 lines
14 KiB
435 lines
14 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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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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#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/refcount.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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#define FASTREUSEPORT_ANY 1 |
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#define FASTREUSEPORT_STRICT 2 |
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struct inet_bind_bucket { |
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possible_net_t ib_net; |
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int l3mdev; |
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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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#if IS_ENABLED(CONFIG_IPV6) |
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struct in6_addr fast_v6_rcv_saddr; |
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#endif |
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__be32 fast_rcv_saddr; |
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unsigned short fast_sk_family; |
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bool fast_ipv6_only; |
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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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unsigned int count; |
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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 kmem_cache *bind_bucket_cachep; |
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struct inet_bind_hashbucket *bhash; |
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unsigned int bhash_size; |
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/* The 2nd listener table hashed by local port and address */ |
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unsigned int lhash2_mask; |
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struct inet_listen_hashbucket *lhash2; |
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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 listening_hash. |
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* This is the only table where wildcard'd TCP sockets can |
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* exist. listening_hash is only hashed by local port number. |
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* If lhash2 is initialized, the same socket will also be hashed |
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* to lhash2 by port and address. |
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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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#define inet_lhash2_for_each_icsk_continue(__icsk) \ |
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hlist_for_each_entry_continue(__icsk, icsk_listen_portaddr_node) |
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#define inet_lhash2_for_each_icsk(__icsk, list) \ |
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hlist_for_each_entry(__icsk, list, icsk_listen_portaddr_node) |
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#define inet_lhash2_for_each_icsk_rcu(__icsk, list) \ |
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hlist_for_each_entry_rcu(__icsk, list, icsk_listen_portaddr_node) |
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static inline struct inet_listen_hashbucket * |
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inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash) |
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{ |
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return &h->lhash2[hash & h->lhash2_mask]; |
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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_hashinfo2_free_mod(struct inet_hashinfo *h) |
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{ |
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kfree(h->lhash2); |
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h->lhash2 = NULL; |
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} |
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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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static inline bool inet_sk_bound_dev_eq(struct net *net, int bound_dev_if, |
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int dif, int sdif) |
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{ |
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#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) |
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return inet_bound_dev_eq(!!net->ipv4.sysctl_tcp_l3mdev_accept, |
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bound_dev_if, dif, sdif); |
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#else |
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return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); |
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#endif |
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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, int l3mdev); |
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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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void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, |
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unsigned long numentries, int scale, |
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unsigned long low_limit, |
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unsigned long high_limit); |
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int inet_hashinfo2_init_mod(struct inet_hashinfo *h); |
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bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk); |
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bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, |
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bool *found_dup_sk); |
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int __inet_hash(struct sock *sk, struct sock *osk); |
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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, const int sdif); |
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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, int sdif) |
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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, sdif); |
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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, __sdif) \ |
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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 == (__dif)) || \ |
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((__sk)->sk_bound_dev_if == (__sdif))) && \ |
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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, __sdif) \ |
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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 == (__dif)) || \ |
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((__sk)->sk_bound_dev_if == (__sdif))) && \ |
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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, const int sdif); |
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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, 0); |
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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, const int sdif, |
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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, sdif); |
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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, sdif); |
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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, 0, &refcounted); |
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if (sk && !refcounted && !refcount_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, |
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const int sdif, |
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bool *refcounted) |
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{ |
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struct sock *sk = skb_steal_sock(skb, refcounted); |
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const struct iphdr *iph = ip_hdr(skb); |
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if (sk) |
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return sk; |
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return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb, |
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doff, iph->saddr, sport, |
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iph->daddr, dport, inet_iif(skb), sdif, |
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refcounted); |
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} |
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u32 inet6_ehashfn(const 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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static inline void sk_daddr_set(struct sock *sk, __be32 addr) |
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{ |
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sk->sk_daddr = addr; /* alias of inet_daddr */ |
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#if IS_ENABLED(CONFIG_IPV6) |
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ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr); |
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#endif |
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} |
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static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr) |
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{ |
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sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */ |
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#if IS_ENABLED(CONFIG_IPV6) |
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ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr); |
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#endif |
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} |
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int __inet_hash_connect(struct inet_timewait_death_row *death_row, |
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struct sock *sk, u32 port_offset, |
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int (*check_established)(struct inet_timewait_death_row *, |
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struct sock *, __u16, |
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struct inet_timewait_sock **)); |
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int inet_hash_connect(struct inet_timewait_death_row *death_row, |
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struct sock *sk); |
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#endif /* _INET_HASHTABLES_H */
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