1 files changed, 933 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
new file mode 100644
index 000000000..5295a579e
--- /dev/null
+++ b/net/ipv4/inet_hashtables.c
@@ -0,0 +1,933 @@
+/*
+ * 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.
+ *
+ *		Generic INET transport hashtables
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/vmalloc.h>
+#include <linux/bootmem.h>
+
+#include <net/addrconf.h>
+#include <net/inet_connection_sock.h>
+#include <net/inet_hashtables.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/inet6_hashtables.h>
+#endif
+#include <net/secure_seq.h>
+#include <net/ip.h>
+#include <net/tcp.h>
+#include <net/sock_reuseport.h>
+
+static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
+			const __u16 lport, const __be32 faddr,
+			const __be16 fport)
+{
+	static u32 inet_ehash_secret __read_mostly;
+
+	net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
+
+	return __inet_ehashfn(laddr, lport, faddr, fport,
+			      inet_ehash_secret + net_hash_mix(net));
+}
+
+/* This function handles inet_sock, but also timewait and request sockets
+ * for IPv4/IPv6.
+ */
+static u32 sk_ehashfn(const struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6 &&
+	    !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+		return inet6_ehashfn(sock_net(sk),
+				     &sk->sk_v6_rcv_saddr, sk->sk_num,
+				     &sk->sk_v6_daddr, sk->sk_dport);
+#endif
+	return inet_ehashfn(sock_net(sk),
+			    sk->sk_rcv_saddr, sk->sk_num,
+			    sk->sk_daddr, sk->sk_dport);
+}
+
+/*
+ * Allocate and initialize a new local port bind bucket.
+ * The bindhash mutex for snum's hash chain must be held here.
+ */
+struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
+						 struct net *net,
+						 struct inet_bind_hashbucket *head,
+						 const unsigned short snum)
+{
+	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
+
+	if (tb) {
+		write_pnet(&tb->ib_net, net);
+		tb->port      = snum;
+		tb->fastreuse = 0;
+		tb->fastreuseport = 0;
+		INIT_HLIST_HEAD(&tb->owners);
+		hlist_add_head(&tb->node, &head->chain);
+	}
+	return tb;
+}
+
+/*
+ * Caller must hold hashbucket lock for this tb with local BH disabled
+ */
+void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
+{
+	if (hlist_empty(&tb->owners)) {
+		__hlist_del(&tb->node);
+		kmem_cache_free(cachep, tb);
+	}
+}
+
+void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
+		    const unsigned short snum)
+{
+	inet_sk(sk)->inet_num = snum;
+	sk_add_bind_node(sk, &tb->owners);
+	inet_csk(sk)->icsk_bind_hash = tb;
+}
+
+/*
+ * Get rid of any references to a local port held by the given sock.
+ */
+static void __inet_put_port(struct sock *sk)
+{
+	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
+			hashinfo->bhash_size);
+	struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
+	struct inet_bind_bucket *tb;
+
+	spin_lock(&head->lock);
+	tb = inet_csk(sk)->icsk_bind_hash;
+	__sk_del_bind_node(sk);
+	inet_csk(sk)->icsk_bind_hash = NULL;
+	inet_sk(sk)->inet_num = 0;
+	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
+	spin_unlock(&head->lock);
+}
+
+void inet_put_port(struct sock *sk)
+{
+	local_bh_disable();
+	__inet_put_port(sk);
+	local_bh_enable();
+}
+EXPORT_SYMBOL(inet_put_port);
+
+int __inet_inherit_port(const struct sock *sk, struct sock *child)
+{
+	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
+	unsigned short port = inet_sk(child)->inet_num;
+	const int bhash = inet_bhashfn(sock_net(sk), port,
+			table->bhash_size);
+	struct inet_bind_hashbucket *head = &table->bhash[bhash];
+	struct inet_bind_bucket *tb;
+
+	spin_lock(&head->lock);
+	tb = inet_csk(sk)->icsk_bind_hash;
+	if (unlikely(!tb)) {
+		spin_unlock(&head->lock);
+		return -ENOENT;
+	}
+	if (tb->port != port) {
+		/* NOTE: using tproxy and redirecting skbs to a proxy
+		 * on a different listener port breaks the assumption
+		 * that the listener socket's icsk_bind_hash is the same
+		 * as that of the child socket. We have to look up or
+		 * create a new bind bucket for the child here. */
+		inet_bind_bucket_for_each(tb, &head->chain) {
+			if (net_eq(ib_net(tb), sock_net(sk)) &&
+			    tb->port == port)
+				break;
+		}
+		if (!tb) {
+			tb = inet_bind_bucket_create(table->bind_bucket_cachep,
+						     sock_net(sk), head, port);
+			if (!tb) {
+				spin_unlock(&head->lock);
+				return -ENOMEM;
+			}
+		}
+		inet_csk_update_fastreuse(tb, child);
+	}
+	inet_bind_hash(child, tb, port);
+	spin_unlock(&head->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__inet_inherit_port);
+
+static struct inet_listen_hashbucket *
+inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
+{
+	u32 hash;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6)
+		hash = ipv6_portaddr_hash(sock_net(sk),
+					  &sk->sk_v6_rcv_saddr,
+					  inet_sk(sk)->inet_num);
+	else
+#endif
+		hash = ipv4_portaddr_hash(sock_net(sk),
+					  inet_sk(sk)->inet_rcv_saddr,
+					  inet_sk(sk)->inet_num);
+	return inet_lhash2_bucket(h, hash);
+}
+
+static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
+{
+	struct inet_listen_hashbucket *ilb2;
+
+	if (!h->lhash2)
+		return;
+
+	ilb2 = inet_lhash2_bucket_sk(h, sk);
+
+	spin_lock(&ilb2->lock);
+	if (sk->sk_reuseport && sk->sk_family == AF_INET6)
+		hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
+				   &ilb2->head);
+	else
+		hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
+				   &ilb2->head);
+	ilb2->count++;
+	spin_unlock(&ilb2->lock);
+}
+
+static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
+{
+	struct inet_listen_hashbucket *ilb2;
+
+	if (!h->lhash2 ||
+	    WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
+		return;
+
+	ilb2 = inet_lhash2_bucket_sk(h, sk);
+
+	spin_lock(&ilb2->lock);
+	hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
+	ilb2->count--;
+	spin_unlock(&ilb2->lock);
+}
+
+static inline int compute_score(struct sock *sk, struct net *net,
+				const unsigned short hnum, const __be32 daddr,
+				const int dif, const int sdif, bool exact_dif)
+{
+	int score = -1;
+	struct inet_sock *inet = inet_sk(sk);
+
+	if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
+			!ipv6_only_sock(sk)) {
+		__be32 rcv_saddr = inet->inet_rcv_saddr;
+		score = sk->sk_family == PF_INET ? 2 : 1;
+		if (rcv_saddr) {
+			if (rcv_saddr != daddr)
+				return -1;
+			score += 4;
+		}
+		if (sk->sk_bound_dev_if || exact_dif) {
+			bool dev_match = (sk->sk_bound_dev_if == dif ||
+					  sk->sk_bound_dev_if == sdif);
+
+			if (!dev_match)
+				return -1;
+			if (sk->sk_bound_dev_if)
+				score += 4;
+		}
+		if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
+			score++;
+	}
+	return score;
+}
+
+/*
+ * Here are some nice properties to exploit here. The BSD API
+ * does not allow a listening sock to specify the remote port nor the
+ * remote address for the connection. So always assume those are both
+ * wildcarded during the search since they can never be otherwise.
+ */
+
+/* called with rcu_read_lock() : No refcount taken on the socket */
+static struct sock *inet_lhash2_lookup(struct net *net,
+				struct inet_listen_hashbucket *ilb2,
+				struct sk_buff *skb, int doff,
+				const __be32 saddr, __be16 sport,
+				const __be32 daddr, const unsigned short hnum,
+				const int dif, const int sdif)
+{
+	bool exact_dif = inet_exact_dif_match(net, skb);
+	struct inet_connection_sock *icsk;
+	struct sock *sk, *result = NULL;
+	int score, hiscore = 0;
+	u32 phash = 0;
+
+	inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
+		sk = (struct sock *)icsk;
+		score = compute_score(sk, net, hnum, daddr,
+				      dif, sdif, exact_dif);
+		if (score > hiscore) {
+			if (sk->sk_reuseport) {
+				phash = inet_ehashfn(net, daddr, hnum,
+						     saddr, sport);
+				result = reuseport_select_sock(sk, phash,
+							       skb, doff);
+				if (result)
+					return result;
+			}
+			result = sk;
+			hiscore = score;
+		}
+	}
+
+	return result;
+}
+
+struct sock *__inet_lookup_listener(struct net *net,
+				    struct inet_hashinfo *hashinfo,
+				    struct sk_buff *skb, int doff,
+				    const __be32 saddr, __be16 sport,
+				    const __be32 daddr, const unsigned short hnum,
+				    const int dif, const int sdif)
+{
+	unsigned int hash = inet_lhashfn(net, hnum);
+	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
+	bool exact_dif = inet_exact_dif_match(net, skb);
+	struct inet_listen_hashbucket *ilb2;
+	struct sock *sk, *result = NULL;
+	struct hlist_nulls_node *node;
+	int score, hiscore = 0;
+	unsigned int hash2;
+	u32 phash = 0;
+
+	if (ilb->count <= 10 || !hashinfo->lhash2)
+		goto port_lookup;
+
+	/* Too many sk in the ilb bucket (which is hashed by port alone).
+	 * Try lhash2 (which is hashed by port and addr) instead.
+	 */
+
+	hash2 = ipv4_portaddr_hash(net, daddr, hnum);
+	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
+	if (ilb2->count > ilb->count)
+		goto port_lookup;
+
+	result = inet_lhash2_lookup(net, ilb2, skb, doff,
+				    saddr, sport, daddr, hnum,
+				    dif, sdif);
+	if (result)
+		goto done;
+
+	/* Lookup lhash2 with INADDR_ANY */
+
+	hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
+	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
+	if (ilb2->count > ilb->count)
+		goto port_lookup;
+
+	result = inet_lhash2_lookup(net, ilb2, skb, doff,
+				    saddr, sport, daddr, hnum,
+				    dif, sdif);
+	goto done;
+
+port_lookup:
+	sk_nulls_for_each_rcu(sk, node, &ilb->nulls_head) {
+		score = compute_score(sk, net, hnum, daddr,
+				      dif, sdif, exact_dif);
+		if (score > hiscore) {
+			if (sk->sk_reuseport) {
+				phash = inet_ehashfn(net, daddr, hnum,
+						     saddr, sport);
+				result = reuseport_select_sock(sk, phash,
+							       skb, doff);
+				if (result)
+					goto done;
+			}
+			result = sk;
+			hiscore = score;
+		}
+	}
+done:
+	if (unlikely(IS_ERR(result)))
+		return NULL;
+	return result;
+}
+EXPORT_SYMBOL_GPL(__inet_lookup_listener);
+
+/* All sockets share common refcount, but have different destructors */
+void sock_gen_put(struct sock *sk)
+{
+	if (!refcount_dec_and_test(&sk->sk_refcnt))
+		return;
+
+	if (sk->sk_state == TCP_TIME_WAIT)
+		inet_twsk_free(inet_twsk(sk));
+	else if (sk->sk_state == TCP_NEW_SYN_RECV)
+		reqsk_free(inet_reqsk(sk));
+	else
+		sk_free(sk);
+}
+EXPORT_SYMBOL_GPL(sock_gen_put);
+
+void sock_edemux(struct sk_buff *skb)
+{
+	sock_gen_put(skb->sk);
+}
+EXPORT_SYMBOL(sock_edemux);
+
+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)
+{
+	INET_ADDR_COOKIE(acookie, saddr, daddr);
+	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
+	struct sock *sk;
+	const struct hlist_nulls_node *node;
+	/* Optimize here for direct hit, only listening connections can
+	 * have wildcards anyways.
+	 */
+	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
+	unsigned int slot = hash & hashinfo->ehash_mask;
+	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
+
+begin:
+	sk_nulls_for_each_rcu(sk, node, &head->chain) {
+		if (sk->sk_hash != hash)
+			continue;
+		if (likely(INET_MATCH(sk, net, acookie,
+				      saddr, daddr, ports, dif, sdif))) {
+			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
+				goto out;
+			if (unlikely(!INET_MATCH(sk, net, acookie,
+						 saddr, daddr, ports,
+						 dif, sdif))) {
+				sock_gen_put(sk);
+				goto begin;
+			}
+			goto found;
+		}
+	}
+	/*
+	 * if the nulls value we got at the end of this lookup is
+	 * not the expected one, we must restart lookup.
+	 * We probably met an item that was moved to another chain.
+	 */
+	if (get_nulls_value(node) != slot)
+		goto begin;
+out:
+	sk = NULL;
+found:
+	return sk;
+}
+EXPORT_SYMBOL_GPL(__inet_lookup_established);
+
+/* called with local bh disabled */
+static int __inet_check_established(struct inet_timewait_death_row *death_row,
+				    struct sock *sk, __u16 lport,
+				    struct inet_timewait_sock **twp)
+{
+	struct inet_hashinfo *hinfo = death_row->hashinfo;
+	struct inet_sock *inet = inet_sk(sk);
+	__be32 daddr = inet->inet_rcv_saddr;
+	__be32 saddr = inet->inet_daddr;
+	int dif = sk->sk_bound_dev_if;
+	struct net *net = sock_net(sk);
+	int sdif = l3mdev_master_ifindex_by_index(net, dif);
+	INET_ADDR_COOKIE(acookie, saddr, daddr);
+	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
+	unsigned int hash = inet_ehashfn(net, daddr, lport,
+					 saddr, inet->inet_dport);
+	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
+	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
+	struct sock *sk2;
+	const struct hlist_nulls_node *node;
+	struct inet_timewait_sock *tw = NULL;
+
+	spin_lock(lock);
+
+	sk_nulls_for_each(sk2, node, &head->chain) {
+		if (sk2->sk_hash != hash)
+			continue;
+
+		if (likely(INET_MATCH(sk2, net, acookie,
+					 saddr, daddr, ports, dif, sdif))) {
+			if (sk2->sk_state == TCP_TIME_WAIT) {
+				tw = inet_twsk(sk2);
+				if (twsk_unique(sk, sk2, twp))
+					break;
+			}
+			goto not_unique;
+		}
+	}
+
+	/* Must record num and sport now. Otherwise we will see
+	 * in hash table socket with a funny identity.
+	 */
+	inet->inet_num = lport;
+	inet->inet_sport = htons(lport);
+	sk->sk_hash = hash;
+	WARN_ON(!sk_unhashed(sk));
+	__sk_nulls_add_node_rcu(sk, &head->chain);
+	if (tw) {
+		sk_nulls_del_node_init_rcu((struct sock *)tw);
+		__NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
+	}
+	spin_unlock(lock);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+
+	if (twp) {
+		*twp = tw;
+	} else if (tw) {
+		/* Silly. Should hash-dance instead... */
+		inet_twsk_deschedule_put(tw);
+	}
+	return 0;
+
+not_unique:
+	spin_unlock(lock);
+	return -EADDRNOTAVAIL;
+}
+
+static u64 inet_sk_port_offset(const struct sock *sk)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+
+	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
+					  inet->inet_daddr,
+					  inet->inet_dport);
+}
+
+/* Searches for an exsiting socket in the ehash bucket list.
+ * Returns true if found, false otherwise.
+ */
+static bool inet_ehash_lookup_by_sk(struct sock *sk,
+				    struct hlist_nulls_head *list)
+{
+	const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num);
+	const int sdif = sk->sk_bound_dev_if;
+	const int dif = sk->sk_bound_dev_if;
+	const struct hlist_nulls_node *node;
+	struct net *net = sock_net(sk);
+	struct sock *esk;
+
+	INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr);
+
+	sk_nulls_for_each_rcu(esk, node, list) {
+		if (esk->sk_hash != sk->sk_hash)
+			continue;
+		if (sk->sk_family == AF_INET) {
+			if (unlikely(INET_MATCH(esk, net, acookie,
+						sk->sk_daddr,
+						sk->sk_rcv_saddr,
+						ports, dif, sdif))) {
+				return true;
+			}
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (sk->sk_family == AF_INET6) {
+			if (unlikely(INET6_MATCH(esk, net,
+						 &sk->sk_v6_daddr,
+						 &sk->sk_v6_rcv_saddr,
+						 ports, dif, sdif))) {
+				return true;
+			}
+		}
+#endif
+	}
+	return false;
+}
+
+/* Insert a socket into ehash, and eventually remove another one
+ * (The another one can be a SYN_RECV or TIMEWAIT)
+ * If an existing socket already exists, socket sk is not inserted,
+ * and sets found_dup_sk parameter to true.
+ */
+bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
+{
+	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct hlist_nulls_head *list;
+	struct inet_ehash_bucket *head;
+	spinlock_t *lock;
+	bool ret = true;
+
+	WARN_ON_ONCE(!sk_unhashed(sk));
+
+	sk->sk_hash = sk_ehashfn(sk);
+	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
+	list = &head->chain;
+	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+
+	spin_lock(lock);
+	if (osk) {
+		WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
+		ret = sk_nulls_del_node_init_rcu(osk);
+	} else if (found_dup_sk) {
+		*found_dup_sk = inet_ehash_lookup_by_sk(sk, list);
+		if (*found_dup_sk)
+			ret = false;
+	}
+
+	if (ret)
+		__sk_nulls_add_node_rcu(sk, list);
+
+	spin_unlock(lock);
+
+	return ret;
+}
+
+bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk)
+{
+	bool ok = inet_ehash_insert(sk, osk, found_dup_sk);
+
+	if (ok) {
+		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+	} else {
+		percpu_counter_inc(sk->sk_prot->orphan_count);
+		inet_sk_set_state(sk, TCP_CLOSE);
+		sock_set_flag(sk, SOCK_DEAD);
+		inet_csk_destroy_sock(sk);
+	}
+	return ok;
+}
+EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
+
+static int inet_reuseport_add_sock(struct sock *sk,
+				   struct inet_listen_hashbucket *ilb)
+{
+	struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
+	const struct hlist_nulls_node *node;
+	struct sock *sk2;
+	kuid_t uid = sock_i_uid(sk);
+
+	sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) {
+		if (sk2 != sk &&
+		    sk2->sk_family == sk->sk_family &&
+		    ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
+		    sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
+		    inet_csk(sk2)->icsk_bind_hash == tb &&
+		    sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
+		    inet_rcv_saddr_equal(sk, sk2, false))
+			return reuseport_add_sock(sk, sk2,
+						  inet_rcv_saddr_any(sk));
+	}
+
+	return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
+}
+
+int __inet_hash(struct sock *sk, struct sock *osk)
+{
+	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_listen_hashbucket *ilb;
+	int err = 0;
+
+	if (sk->sk_state != TCP_LISTEN) {
+		inet_ehash_nolisten(sk, osk, NULL);
+		return 0;
+	}
+	WARN_ON(!sk_unhashed(sk));
+	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+
+	spin_lock(&ilb->lock);
+	if (sk->sk_reuseport) {
+		err = inet_reuseport_add_sock(sk, ilb);
+		if (err)
+			goto unlock;
+	}
+	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
+		sk->sk_family == AF_INET6)
+		__sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head);
+	else
+		__sk_nulls_add_node_rcu(sk, &ilb->nulls_head);
+	inet_hash2(hashinfo, sk);
+	ilb->count++;
+	sock_set_flag(sk, SOCK_RCU_FREE);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+unlock:
+	spin_unlock(&ilb->lock);
+
+	return err;
+}
+EXPORT_SYMBOL(__inet_hash);
+
+int inet_hash(struct sock *sk)
+{
+	int err = 0;
+
+	if (sk->sk_state != TCP_CLOSE) {
+		local_bh_disable();
+		err = __inet_hash(sk, NULL);
+		local_bh_enable();
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(inet_hash);
+
+void inet_unhash(struct sock *sk)
+{
+	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_listen_hashbucket *ilb = NULL;
+	spinlock_t *lock;
+
+	if (sk_unhashed(sk))
+		return;
+
+	if (sk->sk_state == TCP_LISTEN) {
+		ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+		lock = &ilb->lock;
+	} else {
+		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+	}
+	spin_lock_bh(lock);
+	if (sk_unhashed(sk))
+		goto unlock;
+
+	if (rcu_access_pointer(sk->sk_reuseport_cb))
+		reuseport_detach_sock(sk);
+	if (ilb) {
+		inet_unhash2(hashinfo, sk);
+		ilb->count--;
+	}
+	__sk_nulls_del_node_init_rcu(sk);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+unlock:
+	spin_unlock_bh(lock);
+}
+EXPORT_SYMBOL_GPL(inet_unhash);
+
+/* RFC 6056 3.3.4.  Algorithm 4: Double-Hash Port Selection Algorithm
+ * Note that we use 32bit integers (vs RFC 'short integers')
+ * because 2^16 is not a multiple of num_ephemeral and this
+ * property might be used by clever attacker.
+ * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, though
+ * attacks were since demonstrated, thus we use 65536 instead to really
+ * give more isolation and privacy, at the expense of 256kB of kernel
+ * memory.
+ */
+#define INET_TABLE_PERTURB_SHIFT 16
+#define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT)
+static u32 *table_perturb;
+
+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 **))
+{
+	struct inet_hashinfo *hinfo = death_row->hashinfo;
+	struct inet_timewait_sock *tw = NULL;
+	struct inet_bind_hashbucket *head;
+	int port = inet_sk(sk)->inet_num;
+	struct net *net = sock_net(sk);
+	struct inet_bind_bucket *tb;
+	u32 remaining, offset;
+	int ret, i, low, high;
+	u32 index;
+
+	if (port) {
+		head = &hinfo->bhash[inet_bhashfn(net, port,
+						  hinfo->bhash_size)];
+		tb = inet_csk(sk)->icsk_bind_hash;
+		spin_lock_bh(&head->lock);
+		if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
+			inet_ehash_nolisten(sk, NULL, NULL);
+			spin_unlock_bh(&head->lock);
+			return 0;
+		}
+		spin_unlock(&head->lock);
+		/* No definite answer... Walk to established hash table */
+		ret = check_established(death_row, sk, port, NULL);
+		local_bh_enable();
+		return ret;
+	}
+
+	inet_get_local_port_range(net, &low, &high);
+	high++; /* [32768, 60999] -> [32768, 61000[ */
+	remaining = high - low;
+	if (likely(remaining > 1))
+		remaining &= ~1U;
+
+	net_get_random_once(table_perturb,
+			    INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb));
+	index = port_offset & (INET_TABLE_PERTURB_SIZE - 1);
+
+	offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32);
+	offset %= remaining;
+
+	/* In first pass we try ports of @low parity.
+	 * inet_csk_get_port() does the opposite choice.
+	 */
+	offset &= ~1U;
+other_parity_scan:
+	port = low + offset;
+	for (i = 0; i < remaining; i += 2, port += 2) {
+		if (unlikely(port >= high))
+			port -= remaining;
+		if (inet_is_local_reserved_port(net, port))
+			continue;
+		head = &hinfo->bhash[inet_bhashfn(net, port,
+						  hinfo->bhash_size)];
+		spin_lock_bh(&head->lock);
+
+		/* Does not bother with rcv_saddr checks, because
+		 * the established check is already unique enough.
+		 */
+		inet_bind_bucket_for_each(tb, &head->chain) {
+			if (net_eq(ib_net(tb), net) && tb->port == port) {
+				if (tb->fastreuse >= 0 ||
+				    tb->fastreuseport >= 0)
+					goto next_port;
+				WARN_ON(hlist_empty(&tb->owners));
+				if (!check_established(death_row, sk,
+						       port, &tw))
+					goto ok;
+				goto next_port;
+			}
+		}
+
+		tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
+					     net, head, port);
+		if (!tb) {
+			spin_unlock_bh(&head->lock);
+			return -ENOMEM;
+		}
+		tb->fastreuse = -1;
+		tb->fastreuseport = -1;
+		goto ok;
+next_port:
+		spin_unlock_bh(&head->lock);
+		cond_resched();
+	}
+
+	offset++;
+	if ((offset & 1) && remaining > 1)
+		goto other_parity_scan;
+
+	return -EADDRNOTAVAIL;
+
+ok:
+	/* Here we want to add a little bit of randomness to the next source
+	 * port that will be chosen. We use a max() with a random here so that
+	 * on low contention the randomness is maximal and on high contention
+	 * it may be inexistent.
+	 */
+	i = max_t(int, i, (prandom_u32() & 7) * 2);
+	WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2);
+
+	/* Head lock still held and bh's disabled */
+	inet_bind_hash(sk, tb, port);
+	if (sk_unhashed(sk)) {
+		inet_sk(sk)->inet_sport = htons(port);
+		inet_ehash_nolisten(sk, (struct sock *)tw, NULL);
+	}
+	if (tw)
+		inet_twsk_bind_unhash(tw, hinfo);
+	spin_unlock(&head->lock);
+	if (tw)
+		inet_twsk_deschedule_put(tw);
+	local_bh_enable();
+	return 0;
+}
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+int inet_hash_connect(struct inet_timewait_death_row *death_row,
+		      struct sock *sk)
+{
+	u64 port_offset = 0;
+
+	if (!inet_sk(sk)->inet_num)
+		port_offset = inet_sk_port_offset(sk);
+	return __inet_hash_connect(death_row, sk, port_offset,
+				   __inet_check_established);
+}
+EXPORT_SYMBOL_GPL(inet_hash_connect);
+
+void inet_hashinfo_init(struct inet_hashinfo *h)
+{
+	int i;
+
+	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
+		spin_lock_init(&h->listening_hash[i].lock);
+		INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head,
+				      i + LISTENING_NULLS_BASE);
+		h->listening_hash[i].count = 0;
+	}
+
+	h->lhash2 = NULL;
+}
+EXPORT_SYMBOL_GPL(inet_hashinfo_init);
+
+void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
+				unsigned long numentries, int scale,
+				unsigned long low_limit,
+				unsigned long high_limit)
+{
+	unsigned int i;
+
+	h->lhash2 = alloc_large_system_hash(name,
+					    sizeof(*h->lhash2),
+					    numentries,
+					    scale,
+					    0,
+					    NULL,
+					    &h->lhash2_mask,
+					    low_limit,
+					    high_limit);
+
+	for (i = 0; i <= h->lhash2_mask; i++) {
+		spin_lock_init(&h->lhash2[i].lock);
+		INIT_HLIST_HEAD(&h->lhash2[i].head);
+		h->lhash2[i].count = 0;
+	}
+
+	/* this one is used for source ports of outgoing connections */
+	table_perturb = kmalloc_array(INET_TABLE_PERTURB_SIZE,
+				      sizeof(*table_perturb), GFP_KERNEL);
+	if (!table_perturb)
+		panic("TCP: failed to alloc table_perturb");
+}
+
+int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
+{
+	unsigned int locksz = sizeof(spinlock_t);
+	unsigned int i, nblocks = 1;
+
+	if (locksz != 0) {
+		/* allocate 2 cache lines or at least one spinlock per cpu */
+		nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
+		nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
+
+		/* no more locks than number of hash buckets */
+		nblocks = min(nblocks, hashinfo->ehash_mask + 1);
+
+		hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
+		if (!hashinfo->ehash_locks)
+			return -ENOMEM;
+
+		for (i = 0; i < nblocks; i++)
+			spin_lock_init(&hashinfo->ehash_locks[i]);
+	}
+	hashinfo->ehash_locks_mask = nblocks - 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);