diff options
Diffstat (limited to 'include/net/inet_hashtables.h')
| -rw-r--r-- | include/net/inet_hashtables.h | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h new file mode 100644 index 000000000..c9e387d17 --- /dev/null +++ b/include/net/inet_hashtables.h @@ -0,0 +1,413 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Authors: Lotsa people, from code originally in tcp + */ + +#ifndef _INET_HASHTABLES_H +#define _INET_HASHTABLES_H + + +#include <linux/interrupt.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/socket.h> +#include <linux/spinlock.h> +#include <linux/types.h> +#include <linux/wait.h> + +#include <net/inet_connection_sock.h> +#include <net/inet_sock.h> +#include <net/sock.h> +#include <net/route.h> +#include <net/tcp_states.h> +#include <net/netns/hash.h> + +#include <linux/refcount.h> +#include <asm/byteorder.h> + +/* This is for all connections with a full identity, no wildcards. + * The 'e' prefix stands for Establish, but we really put all sockets + * but LISTEN ones. + */ +struct inet_ehash_bucket { + struct hlist_nulls_head chain; +}; + +/* There are a few simple rules, which allow for local port reuse by + * an application. In essence: + * + * 1) Sockets bound to different interfaces may share a local port. + * Failing that, goto test 2. + * 2) If all sockets have sk->sk_reuse set, and none of them are in + * TCP_LISTEN state, the port may be shared. + * Failing that, goto test 3. + * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local + * address, and none of them are the same, the port may be + * shared. + * Failing this, the port cannot be shared. + * + * The interesting point, is test #2. This is what an FTP server does + * all day. To optimize this case we use a specific flag bit defined + * below. As we add sockets to a bind bucket list, we perform a + * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) + * As long as all sockets added to a bind bucket pass this test, + * the flag bit will be set. + * The resulting situation is that tcp_v[46]_verify_bind() can just check + * for this flag bit, if it is set and the socket trying to bind has + * sk->sk_reuse set, we don't even have to walk the owners list at all, + * we return that it is ok to bind this socket to the requested local port. + * + * Sounds like a lot of work, but it is worth it. In a more naive + * implementation (ie. current FreeBSD etc.) the entire list of ports + * must be walked for each data port opened by an ftp server. Needless + * to say, this does not scale at all. With a couple thousand FTP + * users logged onto your box, isn't it nice to know that new data + * ports are created in O(1) time? I thought so. ;-) -DaveM + */ +#define FASTREUSEPORT_ANY 1 +#define FASTREUSEPORT_STRICT 2 + +struct inet_bind_bucket { + possible_net_t ib_net; + int l3mdev; + unsigned short port; + signed char fastreuse; + signed char fastreuseport; + kuid_t fastuid; +#if IS_ENABLED(CONFIG_IPV6) + struct in6_addr fast_v6_rcv_saddr; +#endif + __be32 fast_rcv_saddr; + unsigned short fast_sk_family; + bool fast_ipv6_only; + struct hlist_node node; + struct hlist_head owners; +}; + +static inline struct net *ib_net(struct inet_bind_bucket *ib) +{ + return read_pnet(&ib->ib_net); +} + +#define inet_bind_bucket_for_each(tb, head) \ + hlist_for_each_entry(tb, head, node) + +struct inet_bind_hashbucket { + spinlock_t lock; + struct hlist_head chain; +}; + +/* Sockets can be hashed in established or listening table. + * We must use different 'nulls' end-of-chain value for all hash buckets : + * A socket might transition from ESTABLISH to LISTEN state without + * RCU grace period. A lookup in ehash table needs to handle this case. + */ +#define LISTENING_NULLS_BASE (1U << 29) +struct inet_listen_hashbucket { + spinlock_t lock; + unsigned int count; + union { + struct hlist_head head; + struct hlist_nulls_head nulls_head; + }; +}; + +/* This is for listening sockets, thus all sockets which possess wildcards. */ +#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ + +struct inet_hashinfo { + /* This is for sockets with full identity only. Sockets here will + * always be without wildcards and will have the following invariant: + * + * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE + * + */ + struct inet_ehash_bucket *ehash; + spinlock_t *ehash_locks; + unsigned int ehash_mask; + unsigned int ehash_locks_mask; + + /* Ok, let's try this, I give up, we do need a local binding + * TCP hash as well as the others for fast bind/connect. + */ + struct kmem_cache *bind_bucket_cachep; + struct inet_bind_hashbucket *bhash; + unsigned int bhash_size; + + /* The 2nd listener table hashed by local port and address */ + unsigned int lhash2_mask; + struct inet_listen_hashbucket *lhash2; + + /* All the above members are written once at bootup and + * never written again _or_ are predominantly read-access. + * + * Now align to a new cache line as all the following members + * might be often dirty. + */ + /* All sockets in TCP_LISTEN state will be in listening_hash. + * This is the only table where wildcard'd TCP sockets can + * exist. listening_hash is only hashed by local port number. + * If lhash2 is initialized, the same socket will also be hashed + * to lhash2 by port and address. + */ + struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] + ____cacheline_aligned_in_smp; +}; + +#define inet_lhash2_for_each_icsk_rcu(__icsk, list) \ + hlist_for_each_entry_rcu(__icsk, list, icsk_listen_portaddr_node) + +static inline struct inet_listen_hashbucket * +inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash) +{ + return &h->lhash2[hash & h->lhash2_mask]; +} + +static inline struct inet_ehash_bucket *inet_ehash_bucket( + struct inet_hashinfo *hashinfo, + unsigned int hash) +{ + return &hashinfo->ehash[hash & hashinfo->ehash_mask]; +} + +static inline spinlock_t *inet_ehash_lockp( + struct inet_hashinfo *hashinfo, + unsigned int hash) +{ + return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; +} + +int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo); + +static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h) +{ + kfree(h->lhash2); + h->lhash2 = NULL; +} + +static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) +{ + kvfree(hashinfo->ehash_locks); + hashinfo->ehash_locks = NULL; +} + +struct inet_bind_bucket * +inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, + struct inet_bind_hashbucket *head, + const unsigned short snum, int l3mdev); +void inet_bind_bucket_destroy(struct kmem_cache *cachep, + struct inet_bind_bucket *tb); + +static inline u32 inet_bhashfn(const struct net *net, const __u16 lport, + const u32 bhash_size) +{ + return (lport + net_hash_mix(net)) & (bhash_size - 1); +} + +void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, + const unsigned short snum); + +/* These can have wildcards, don't try too hard. */ +static inline u32 inet_lhashfn(const struct net *net, const unsigned short num) +{ + return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); +} + +static inline int inet_sk_listen_hashfn(const struct sock *sk) +{ + return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); +} + +/* Caller must disable local BH processing. */ +int __inet_inherit_port(const struct sock *sk, struct sock *child); + +void inet_put_port(struct sock *sk); + +void inet_hashinfo_init(struct inet_hashinfo *h); +void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, + unsigned long numentries, int scale, + unsigned long low_limit, + unsigned long high_limit); +int inet_hashinfo2_init_mod(struct inet_hashinfo *h); + +bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk); +bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, + bool *found_dup_sk); +int __inet_hash(struct sock *sk, struct sock *osk); +int inet_hash(struct sock *sk); +void inet_unhash(struct sock *sk); + +struct sock *__inet_lookup_listener(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + const __be32 saddr, const __be16 sport, + const __be32 daddr, + const unsigned short hnum, + const int dif, const int sdif); + +static inline struct sock *inet_lookup_listener(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + __be32 saddr, __be16 sport, + __be32 daddr, __be16 dport, int dif, int sdif) +{ + return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport, + daddr, ntohs(dport), dif, sdif); +} + +/* Socket demux engine toys. */ +/* What happens here is ugly; there's a pair of adjacent fields in + struct inet_sock; __be16 dport followed by __u16 num. We want to + search by pair, so we combine the keys into a single 32bit value + and compare with 32bit value read from &...->dport. Let's at least + make sure that it's not mixed with anything else... + On 64bit targets we combine comparisons with pair of adjacent __be32 + fields in the same way. +*/ +#ifdef __BIG_ENDIAN +#define INET_COMBINED_PORTS(__sport, __dport) \ + ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport))) +#else /* __LITTLE_ENDIAN */ +#define INET_COMBINED_PORTS(__sport, __dport) \ + ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport))) +#endif + +#ifdef __BIG_ENDIAN +#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ + const __addrpair __name = (__force __addrpair) ( \ + (((__force __u64)(__be32)(__saddr)) << 32) | \ + ((__force __u64)(__be32)(__daddr))) +#else /* __LITTLE_ENDIAN */ +#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ + const __addrpair __name = (__force __addrpair) ( \ + (((__force __u64)(__be32)(__daddr)) << 32) | \ + ((__force __u64)(__be32)(__saddr))) +#endif /* __BIG_ENDIAN */ + +static inline bool INET_MATCH(struct net *net, const struct sock *sk, + const __addrpair cookie, const __portpair ports, + int dif, int sdif) +{ + if (!net_eq(sock_net(sk), net) || + sk->sk_portpair != ports || + sk->sk_addrpair != cookie) + return false; + + /* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */ + return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif, + sdif); +} + +/* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need + * not check it for lookups anymore, thanks Alexey. -DaveM + */ +struct sock *__inet_lookup_established(struct net *net, + struct inet_hashinfo *hashinfo, + const __be32 saddr, const __be16 sport, + const __be32 daddr, const u16 hnum, + const int dif, const int sdif); + +static inline struct sock * + inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, + const __be32 saddr, const __be16 sport, + const __be32 daddr, const __be16 dport, + const int dif) +{ + return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, + ntohs(dport), dif, 0); +} + +static inline struct sock *__inet_lookup(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + const __be32 saddr, const __be16 sport, + const __be32 daddr, const __be16 dport, + const int dif, const int sdif, + bool *refcounted) +{ + u16 hnum = ntohs(dport); + struct sock *sk; + + sk = __inet_lookup_established(net, hashinfo, saddr, sport, + daddr, hnum, dif, sdif); + *refcounted = true; + if (sk) + return sk; + *refcounted = false; + return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, + sport, daddr, hnum, dif, sdif); +} + +static inline struct sock *inet_lookup(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + const __be32 saddr, const __be16 sport, + const __be32 daddr, const __be16 dport, + const int dif) +{ + struct sock *sk; + bool refcounted; + + sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, + dport, dif, 0, &refcounted); + + if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) + sk = NULL; + return sk; +} + +static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, + struct sk_buff *skb, + int doff, + const __be16 sport, + const __be16 dport, + const int sdif, + bool *refcounted) +{ + struct sock *sk = skb_steal_sock(skb, refcounted); + const struct iphdr *iph = ip_hdr(skb); + + 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), sdif, + refcounted); +} + +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, u64 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 */ |