cregit-Linux how code gets into the kernel

Release 4.12 include/net/inet_hashtables.h

Directory: include/net
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the BSD Socket
 *              interface as the means of communication with the user level.
 *
 * Authors:     Lotsa people, from code originally in tcp
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#ifndef _INET_HASHTABLES_H

#define _INET_HASHTABLES_H


#include <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/atomic.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;
	
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); }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet23100.00%1100.00%
Total23100.00%1100.00%

#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 */ struct inet_listen_hashbucket { spinlock_t lock; struct hlist_head 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 inet_bind_hashbucket *bhash; unsigned int bhash_size; /* 4 bytes hole on 64 bit */ struct kmem_cache *bind_bucket_cachep; /* 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 here. This is the only * table where wildcard'd TCP sockets can exist. Hash function here * is just local port number. */ struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] ____cacheline_aligned_in_smp; };
static inline struct inet_ehash_bucket *inet_ehash_bucket( struct inet_hashinfo *hashinfo, unsigned int hash) { return &hashinfo->ehash[hash & hashinfo->ehash_mask]; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet31100.00%2100.00%
Total31100.00%2100.00%


static inline spinlock_t *inet_ehash_lockp( struct inet_hashinfo *hashinfo, unsigned int hash) { return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet30100.00%2100.00%
Total30100.00%2100.00%

int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);
static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) { kvfree(hashinfo->ehash_locks); hashinfo->ehash_locks = NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet25100.00%2100.00%
Total25100.00%2100.00%

struct inet_bind_bucket * inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, struct inet_bind_hashbucket *head, const unsigned short snum); 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); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo2259.46%125.00%
Pavel Emelyanov1232.43%250.00%
Eric Dumazet38.11%125.00%
Total37100.00%4100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo2058.82%125.00%
Pavel Emelyanov1235.29%250.00%
Eric Dumazet25.88%125.00%
Total34100.00%4100.00%


static inline int inet_sk_listen_hashfn(const struct sock *sk) { return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo2379.31%133.33%
Pavel Emelyanov517.24%133.33%
Eric Dumazet13.45%133.33%
Total29100.00%3100.00%

/* 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); bool inet_ehash_insert(struct sock *sk, struct sock *osk); bool inet_ehash_nolisten(struct sock *sk, struct sock *osk); 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);
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) { return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport, daddr, ntohs(dport), dif); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu3653.73%120.00%
Craig Gallek1217.91%120.00%
Tom Herbert1014.93%120.00%
Pavel Emelyanov710.45%120.00%
Al Viro22.99%120.00%
Total67100.00%5100.00%

/* 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 #if (BITS_PER_LONG == 64) #ifdef __BIG_ENDIAN #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const __addrpair __name = (__force __addrpair) ( \ (((__force __u64)(__be32)(__saddr)) << 32) | \ ((__force __u64)(__be32)(__daddr))) #else /* __LITTLE_ENDIAN */ #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const __addrpair __name = (__force __addrpair) ( \ (((__force __u64)(__be32)(__daddr)) << 32) | \ ((__force __u64)(__be32)(__saddr))) #endif /* __BIG_ENDIAN */ #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ (((__sk)->sk_portpair == (__ports)) && \ ((__sk)->sk_addrpair == (__cookie)) && \ (!(__sk)->sk_bound_dev_if || \ ((__sk)->sk_bound_dev_if == (__dif))) && \ net_eq(sock_net(__sk), (__net))) #else /* 32-bit arch */ #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const int __name __deprecated __attribute__((unused)) #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ (((__sk)->sk_portpair == (__ports)) && \ ((__sk)->sk_daddr == (__saddr)) && \ ((__sk)->sk_rcv_saddr == (__daddr)) && \ (!(__sk)->sk_bound_dev_if || \ ((__sk)->sk_bound_dev_if == (__dif))) && \ net_eq(sock_net(__sk), (__net))) #endif /* 64-bit arch */ /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need * not check it for lookups anymore, thanks Alexey. -DaveM */ struct sock *__inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const u16 hnum, const int dif);
static inline struct sock * inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, const __be16 sport, const __be32 daddr, const __be16 dport, const int dif) { return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu4981.67%133.33%
Pavel Emelyanov711.67%133.33%
Al Viro46.67%133.33%
Total60100.00%3100.00%


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, bool *refcounted) { u16 hnum = ntohs(dport); struct sock *sk; sk = __inet_lookup_established(net, hashinfo, saddr, sport, daddr, hnum, dif); *refcounted = true; if (sk) return sk; *refcounted = false; return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport, daddr, hnum, dif); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo5948.36%114.29%
Eric Dumazet2419.67%114.29%
Craig Gallek129.84%114.29%
Herbert Xu108.20%114.29%
Pavel Emelyanov97.38%114.29%
Al Viro43.28%114.29%
Tom Herbert43.28%114.29%
Total122100.00%7100.00%


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, &refcounted); if (sk && !refcounted && !atomic_inc_not_zero(&sk->sk_refcnt)) sk = NULL; return sk; }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo5552.88%120.00%
Eric Dumazet2625.00%120.00%
Craig Gallek1211.54%120.00%
Pavel Emelyanov76.73%120.00%
Al Viro43.85%120.00%
Total104100.00%5100.00%


static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, struct sk_buff *skb, int doff, const __be16 sport, 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); }

Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo6864.15%116.67%
Eric Dumazet1413.21%233.33%
KOVACS Krisztian1211.32%116.67%
Craig Gallek76.60%116.67%
David S. Miller54.72%116.67%
Total106100.00%6100.00%

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 }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet40100.00%1100.00%
Total40100.00%1100.00%


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 }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet40100.00%1100.00%
Total40100.00%1100.00%

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 */

Overall Contributors

PersonTokensPropCommitsCommitProp
Arnaldo Carvalho de Melo65845.79%1421.21%
Eric Dumazet38927.07%2436.36%
Pavel Emelyanov1298.98%1015.15%
Herbert Xu976.75%23.03%
Craig Gallek533.69%34.55%
Josef Bacik302.09%11.52%
Tom Herbert302.09%11.52%
Al Viro211.46%23.03%
KOVACS Krisztian120.84%11.52%
David S. Miller50.35%11.52%
Christoph Lameter40.28%11.52%
Joe Perches40.28%11.52%
Arun Sharma10.07%11.52%
Balazs Scheidler10.07%11.52%
Stephen Hemminger10.07%11.52%
Eric W. Biedermann10.07%11.52%
Sasha Levin10.07%11.52%
Total1437100.00%66100.00%
Directory: include/net
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.