Initial import

1 files changed, 416 insertions, 0 deletions

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
new file mode 100644
index 000000000..73fe0f952
--- /dev/null
+++ b/include/net/inet_hashtables.h
@@ -0,0 +1,416 @@
+/*
+ * 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 <linux/vmalloc.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
+ */
+struct inet_bind_bucket {
+	possible_net_t		ib_net;
+	unsigned short		port;
+	signed char		fastreuse;
+	signed char		fastreuseport;
+	kuid_t			fastuid;
+	int			num_owners;
+	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 listening
+ * hash table, or we might find a socket that was closed and
+ * reallocated/inserted into established hash table
+ */
+#define LISTENING_NULLS_BASE (1U << 29)
+struct inet_listen_hashbucket {
+	spinlock_t		lock;
+	struct hlist_nulls_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;
+
+	atomic_t			bsockets;
+};
+
+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];
+}
+
+static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
+{
+	unsigned int i, size = 256;
+#if defined(CONFIG_PROVE_LOCKING)
+	unsigned int nr_pcpus = 2;
+#else
+	unsigned int nr_pcpus = num_possible_cpus();
+#endif
+	if (nr_pcpus >= 4)
+		size = 512;
+	if (nr_pcpus >= 8)
+		size = 1024;
+	if (nr_pcpus >= 16)
+		size = 2048;
+	if (nr_pcpus >= 32)
+		size = 4096;
+	if (sizeof(spinlock_t) != 0) {
+#ifdef CONFIG_NUMA
+		if (size * sizeof(spinlock_t) > PAGE_SIZE)
+			hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
+		else
+#endif
+		hashinfo->ehash_locks =	kmalloc(size * sizeof(spinlock_t),
+						GFP_KERNEL);
+		if (!hashinfo->ehash_locks)
+			return ENOMEM;
+		for (i = 0; i < size; i++)
+			spin_lock_init(&hashinfo->ehash_locks[i]);
+	}
+	hashinfo->ehash_locks_mask = size - 1;
+	return 0;
+}
+
+static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
+{
+	if (hashinfo->ehash_locks) {
+#ifdef CONFIG_NUMA
+		unsigned int size = (hashinfo->ehash_locks_mask + 1) *
+							sizeof(spinlock_t);
+		if (size > PAGE_SIZE)
+			vfree(hashinfo->ehash_locks);
+		else
+#endif
+		kfree(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);
+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(struct sock *sk, struct sock *child);
+
+void inet_put_port(struct sock *sk);
+
+void inet_hashinfo_init(struct inet_hashinfo *h);
+
+int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw);
+int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw);
+void inet_hash(struct sock *sk);
+void inet_unhash(struct sock *sk);
+
+struct sock *__inet_lookup_listener(struct net *net,
+				    struct inet_hashinfo *hashinfo,
+				    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,
+		__be32 saddr, __be16 sport,
+		__be32 daddr, __be16 dport, int dif)
+{
+	return __inet_lookup_listener(net, hashinfo, saddr, sport,
+				      daddr, ntohs(dport), dif);
+}
+
+/* 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
+ *
+ * Local BH must be disabled here.
+ */
+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);
+}
+
+static inline struct sock *__inet_lookup(struct net *net,
+					 struct inet_hashinfo *hashinfo,
+					 const __be32 saddr, const __be16 sport,
+					 const __be32 daddr, const __be16 dport,
+					 const int dif)
+{
+	u16 hnum = ntohs(dport);
+	struct sock *sk = __inet_lookup_established(net, hashinfo,
+				saddr, sport, daddr, hnum, dif);
+
+	return sk ? : __inet_lookup_listener(net, hashinfo, saddr, sport,
+					     daddr, hnum, dif);
+}
+
+static inline struct sock *inet_lookup(struct net *net,
+				       struct inet_hashinfo *hashinfo,
+				       const __be32 saddr, const __be16 sport,
+				       const __be32 daddr, const __be16 dport,
+				       const int dif)
+{
+	struct sock *sk;
+
+	local_bh_disable();
+	sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif);
+	local_bh_enable();
+
+	return sk;
+}
+
+static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
+					     struct sk_buff *skb,
+					     const __be16 sport,
+					     const __be16 dport)
+{
+	struct sock *sk = skb_steal_sock(skb);
+	const struct iphdr *iph = ip_hdr(skb);
+
+	if (sk)
+		return sk;
+	else
+		return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
+				     iph->saddr, sport,
+				     iph->daddr, dport, inet_iif(skb));
+}
+
+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 */