1 files changed, 1114 insertions, 505 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 6acb541c9091..97d57c52b9ad 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -1,3 +1,4 @@
+// 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
@@ -6,11 +7,6 @@
  *		Support for INET connection oriented protocols.
  *
  * Authors:	See the TCP sources
- *
- *		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>
@@ -23,229 +19,591 @@
 #include <net/route.h>
 #include <net/tcp_states.h>
 #include <net/xfrm.h>
+#include <net/tcp.h>
+#include <net/sock_reuseport.h>
+#include <net/addrconf.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+/* match_sk*_wildcard == true:  IPV6_ADDR_ANY equals to any IPv6 addresses
+ *				if IPv6 only, and any IPv4 addresses
+ *				if not IPv6 only
+ * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
+ *				IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
+ *				and 0.0.0.0 equals to 0.0.0.0 only
+ */
+static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
+				 const struct in6_addr *sk2_rcv_saddr6,
+				 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
+				 bool sk1_ipv6only, bool sk2_ipv6only,
+				 bool match_sk1_wildcard,
+				 bool match_sk2_wildcard)
+{
+	int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
+	int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
+
+	/* if both are mapped, treat as IPv4 */
+	if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
+		if (!sk2_ipv6only) {
+			if (sk1_rcv_saddr == sk2_rcv_saddr)
+				return true;
+			return (match_sk1_wildcard && !sk1_rcv_saddr) ||
+				(match_sk2_wildcard && !sk2_rcv_saddr);
+		}
+		return false;
+	}
+
+	if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
+		return true;
+
+	if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard &&
+	    !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
+		return true;
+
+	if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard &&
+	    !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
+		return true;
+
+	if (sk2_rcv_saddr6 &&
+	    ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
+		return true;
+
+	return false;
+}
+#endif
+
+/* match_sk*_wildcard == true:  0.0.0.0 equals to any IPv4 addresses
+ * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
+ *				0.0.0.0 only equals to 0.0.0.0
+ */
+static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
+				 bool sk2_ipv6only, bool match_sk1_wildcard,
+				 bool match_sk2_wildcard)
+{
+	if (!sk2_ipv6only) {
+		if (sk1_rcv_saddr == sk2_rcv_saddr)
+			return true;
+		return (match_sk1_wildcard && !sk1_rcv_saddr) ||
+			(match_sk2_wildcard && !sk2_rcv_saddr);
+	}
+	return false;
+}
 
-#ifdef INET_CSK_DEBUG
-const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
-EXPORT_SYMBOL(inet_csk_timer_bug_msg);
+bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
+			  bool match_wildcard)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6)
+		return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
+					    inet6_rcv_saddr(sk2),
+					    sk->sk_rcv_saddr,
+					    sk2->sk_rcv_saddr,
+					    ipv6_only_sock(sk),
+					    ipv6_only_sock(sk2),
+					    match_wildcard,
+					    match_wildcard);
 #endif
+	return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
+				    ipv6_only_sock(sk2), match_wildcard,
+				    match_wildcard);
+}
+EXPORT_SYMBOL(inet_rcv_saddr_equal);
 
-/*
- * This struct holds the first and last local port number.
+bool inet_rcv_saddr_any(const struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6)
+		return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
+#endif
+	return !sk->sk_rcv_saddr;
+}
+
+/**
+ *	inet_sk_get_local_port_range - fetch ephemeral ports range
+ *	@sk: socket
+ *	@low: pointer to low port
+ *	@high: pointer to high port
+ *
+ *	Fetch netns port range (/proc/sys/net/ipv4/ip_local_port_range)
+ *	Range can be overridden if socket got IP_LOCAL_PORT_RANGE option.
+ *	Returns true if IP_LOCAL_PORT_RANGE was set on this socket.
  */
-struct local_ports sysctl_local_ports __read_mostly = {
-	.lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock),
-	.range = { 32768, 61000 },
-};
+bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
+{
+	int lo, hi, sk_lo, sk_hi;
+	bool local_range = false;
+	u32 sk_range;
+
+	inet_get_local_port_range(sock_net(sk), &lo, &hi);
+
+	sk_range = READ_ONCE(inet_sk(sk)->local_port_range);
+	if (unlikely(sk_range)) {
+		sk_lo = sk_range & 0xffff;
+		sk_hi = sk_range >> 16;
+
+		if (lo <= sk_lo && sk_lo <= hi)
+			lo = sk_lo;
+		if (lo <= sk_hi && sk_hi <= hi)
+			hi = sk_hi;
+		local_range = true;
+	}
+
+	*low = lo;
+	*high = hi;
+	return local_range;
+}
+EXPORT_SYMBOL(inet_sk_get_local_port_range);
+
+static bool inet_use_bhash2_on_bind(const struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6) {
+		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
+			return false;
+
+		if (!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
+			return true;
+	}
+#endif
+	return sk->sk_rcv_saddr != htonl(INADDR_ANY);
+}
 
-unsigned long *sysctl_local_reserved_ports;
-EXPORT_SYMBOL(sysctl_local_reserved_ports);
+static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2,
+			       kuid_t uid, bool relax,
+			       bool reuseport_cb_ok, bool reuseport_ok)
+{
+	int bound_dev_if2;
+
+	if (sk == sk2)
+		return false;
+
+	bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if);
+
+	if (!sk->sk_bound_dev_if || !bound_dev_if2 ||
+	    sk->sk_bound_dev_if == bound_dev_if2) {
+		if (sk->sk_reuse && sk2->sk_reuse &&
+		    sk2->sk_state != TCP_LISTEN) {
+			if (!relax || (!reuseport_ok && sk->sk_reuseport &&
+				       sk2->sk_reuseport && reuseport_cb_ok &&
+				       (sk2->sk_state == TCP_TIME_WAIT ||
+					uid_eq(uid, sk_uid(sk2)))))
+				return true;
+		} else if (!reuseport_ok || !sk->sk_reuseport ||
+			   !sk2->sk_reuseport || !reuseport_cb_ok ||
+			   (sk2->sk_state != TCP_TIME_WAIT &&
+			    !uid_eq(uid, sk_uid(sk2)))) {
+			return true;
+		}
+	}
+	return false;
+}
 
-void inet_get_local_port_range(int *low, int *high)
+static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2,
+				   kuid_t uid, bool relax,
+				   bool reuseport_cb_ok, bool reuseport_ok)
 {
-	unsigned int seq;
+	if (ipv6_only_sock(sk2)) {
+		if (sk->sk_family == AF_INET)
+			return false;
 
-	do {
-		seq = read_seqbegin(&sysctl_local_ports.lock);
+#if IS_ENABLED(CONFIG_IPV6)
+		if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
+			return false;
+#endif
+	}
 
-		*low = sysctl_local_ports.range[0];
-		*high = sysctl_local_ports.range[1];
-	} while (read_seqretry(&sysctl_local_ports.lock, seq));
+	return inet_bind_conflict(sk, sk2, uid, relax,
+				  reuseport_cb_ok, reuseport_ok);
 }
-EXPORT_SYMBOL(inet_get_local_port_range);
 
-int inet_csk_bind_conflict(const struct sock *sk,
-			   const struct inet_bind_bucket *tb, bool relax)
+static bool inet_bhash2_conflict(const struct sock *sk,
+				 const struct inet_bind2_bucket *tb2,
+				 kuid_t uid,
+				 bool relax, bool reuseport_cb_ok,
+				 bool reuseport_ok)
 {
 	struct sock *sk2;
-	int reuse = sk->sk_reuse;
-	int reuseport = sk->sk_reuseport;
-	kuid_t uid = sock_i_uid((struct sock *)sk);
 
-	/*
-	 * Unlike other sk lookup places we do not check
+	sk_for_each_bound(sk2, &tb2->owners) {
+		if (__inet_bhash2_conflict(sk, sk2, uid, relax,
+					   reuseport_cb_ok, reuseport_ok))
+			return true;
+	}
+
+	return false;
+}
+
+#define sk_for_each_bound_bhash(__sk, __tb2, __tb)			\
+	hlist_for_each_entry(__tb2, &(__tb)->bhash2, bhash_node)	\
+		sk_for_each_bound((__sk), &(__tb2)->owners)
+
+/* This should be called only when the tb and tb2 hashbuckets' locks are held */
+static int inet_csk_bind_conflict(const struct sock *sk,
+				  const struct inet_bind_bucket *tb,
+				  const struct inet_bind2_bucket *tb2, /* may be null */
+				  bool relax, bool reuseport_ok)
+{
+	struct sock_reuseport *reuseport_cb;
+	kuid_t uid = sk_uid(sk);
+	bool reuseport_cb_ok;
+	struct sock *sk2;
+
+	rcu_read_lock();
+	reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
+	/* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
+	reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
+	rcu_read_unlock();
+
+	/* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
+	 * ipv4) should have been checked already. We need to do these two
+	 * checks separately because their spinlocks have to be acquired/released
+	 * independently of each other, to prevent possible deadlocks
+	 */
+	if (inet_use_bhash2_on_bind(sk))
+		return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax,
+						   reuseport_cb_ok, reuseport_ok);
+
+	/* Unlike other sk lookup places we do not check
 	 * for sk_net here, since _all_ the socks listed
-	 * in tb->owners list belong to the same net - the
-	 * one this bucket belongs to.
+	 * in tb->owners and tb2->owners list belong
+	 * to the same net - the one this bucket belongs to.
 	 */
+	sk_for_each_bound_bhash(sk2, tb2, tb) {
+		if (!inet_bind_conflict(sk, sk2, uid, relax, reuseport_cb_ok, reuseport_ok))
+			continue;
+
+		if (inet_rcv_saddr_equal(sk, sk2, true))
+			return true;
+	}
+
+	return false;
+}
 
-	sk_for_each_bound(sk2, &tb->owners) {
-		if (sk != sk2 &&
-		    !inet_v6_ipv6only(sk2) &&
-		    (!sk->sk_bound_dev_if ||
-		     !sk2->sk_bound_dev_if ||
-		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
-			if ((!reuse || !sk2->sk_reuse ||
-			    sk2->sk_state == TCP_LISTEN) &&
-			    (!reuseport || !sk2->sk_reuseport ||
-			    (sk2->sk_state != TCP_TIME_WAIT &&
-			     !uid_eq(uid, sock_i_uid(sk2))))) {
-				const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
-				if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
-				    sk2_rcv_saddr == sk_rcv_saddr(sk))
-					break;
+/* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or
+ * INADDR_ANY (if ipv4) socket.
+ *
+ * Caller must hold bhash hashbucket lock with local bh disabled, to protect
+ * against concurrent binds on the port for addr any
+ */
+static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev,
+					  bool relax, bool reuseport_ok)
+{
+	const struct net *net = sock_net(sk);
+	struct sock_reuseport *reuseport_cb;
+	struct inet_bind_hashbucket *head2;
+	struct inet_bind2_bucket *tb2;
+	kuid_t uid = sk_uid(sk);
+	bool conflict = false;
+	bool reuseport_cb_ok;
+
+	rcu_read_lock();
+	reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
+	/* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
+	reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
+	rcu_read_unlock();
+
+	head2 = inet_bhash2_addr_any_hashbucket(sk, net, port);
+
+	spin_lock(&head2->lock);
+
+	inet_bind_bucket_for_each(tb2, &head2->chain) {
+		if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
+			continue;
+
+		if (!inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,	reuseport_ok))
+			continue;
+
+		conflict = true;
+		break;
+	}
+
+	spin_unlock(&head2->lock);
+
+	return conflict;
+}
+
+/*
+ * Find an open port number for the socket.  Returns with the
+ * inet_bind_hashbucket locks held if successful.
+ */
+static struct inet_bind_hashbucket *
+inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret,
+			struct inet_bind2_bucket **tb2_ret,
+			struct inet_bind_hashbucket **head2_ret, int *port_ret)
+{
+	struct inet_hashinfo *hinfo = tcp_get_hashinfo(sk);
+	int i, low, high, attempt_half, port, l3mdev;
+	struct inet_bind_hashbucket *head, *head2;
+	struct net *net = sock_net(sk);
+	struct inet_bind2_bucket *tb2;
+	struct inet_bind_bucket *tb;
+	u32 remaining, offset;
+	bool relax = false;
+
+	l3mdev = inet_sk_bound_l3mdev(sk);
+ports_exhausted:
+	attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
+other_half_scan:
+	inet_sk_get_local_port_range(sk, &low, &high);
+	high++; /* [32768, 60999] -> [32768, 61000[ */
+	if (high - low < 4)
+		attempt_half = 0;
+	if (attempt_half) {
+		int half = low + (((high - low) >> 2) << 1);
+
+		if (attempt_half == 1)
+			high = half;
+		else
+			low = half;
+	}
+	remaining = high - low;
+	if (likely(remaining > 1))
+		remaining &= ~1U;
+
+	offset = get_random_u32_below(remaining);
+	/* __inet_hash_connect() favors ports having @low parity
+	 * We do the opposite to not pollute connect() users.
+	 */
+	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);
+		if (inet_use_bhash2_on_bind(sk)) {
+			if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false))
+				goto next_port;
+		}
+
+		head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
+		spin_lock(&head2->lock);
+		tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
+		inet_bind_bucket_for_each(tb, &head->chain)
+			if (inet_bind_bucket_match(tb, net, port, l3mdev)) {
+				if (!inet_csk_bind_conflict(sk, tb, tb2,
+							    relax, false))
+					goto success;
+				spin_unlock(&head2->lock);
+				goto next_port;
 			}
-			if (!relax && reuse && sk2->sk_reuse &&
-			    sk2->sk_state != TCP_LISTEN) {
-				const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
+		tb = NULL;
+		goto success;
+next_port:
+		spin_unlock_bh(&head->lock);
+		cond_resched();
+	}
 
-				if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
-				    sk2_rcv_saddr == sk_rcv_saddr(sk))
-					break;
+	offset--;
+	if (!(offset & 1))
+		goto other_parity_scan;
+
+	if (attempt_half == 1) {
+		/* OK we now try the upper half of the range */
+		attempt_half = 2;
+		goto other_half_scan;
+	}
+
+	if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) {
+		/* We still have a chance to connect to different destinations */
+		relax = true;
+		goto ports_exhausted;
+	}
+	return NULL;
+success:
+	*port_ret = port;
+	*tb_ret = tb;
+	*tb2_ret = tb2;
+	*head2_ret = head2;
+	return head;
+}
+
+static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
+				     const struct sock *sk)
+{
+	if (tb->fastreuseport <= 0)
+		return 0;
+	if (!sk->sk_reuseport)
+		return 0;
+	if (rcu_access_pointer(sk->sk_reuseport_cb))
+		return 0;
+	if (!uid_eq(tb->fastuid, sk_uid(sk)))
+		return 0;
+	/* We only need to check the rcv_saddr if this tb was once marked
+	 * without fastreuseport and then was reset, as we can only know that
+	 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
+	 * owners list.
+	 */
+	if (tb->fastreuseport == FASTREUSEPORT_ANY)
+		return 1;
+#if IS_ENABLED(CONFIG_IPV6)
+	if (tb->fast_sk_family == AF_INET6)
+		return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
+					    inet6_rcv_saddr(sk),
+					    tb->fast_rcv_saddr,
+					    sk->sk_rcv_saddr,
+					    tb->fast_ipv6_only,
+					    ipv6_only_sock(sk), true, false);
+#endif
+	return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
+				    ipv6_only_sock(sk), true, false);
+}
+
+void inet_csk_update_fastreuse(const struct sock *sk,
+			       struct inet_bind_bucket *tb,
+			       struct inet_bind2_bucket *tb2)
+{
+	bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
+
+	if (hlist_empty(&tb->bhash2)) {
+		tb->fastreuse = reuse;
+		if (sk->sk_reuseport) {
+			tb->fastreuseport = FASTREUSEPORT_ANY;
+			tb->fastuid = sk_uid(sk);
+			tb->fast_rcv_saddr = sk->sk_rcv_saddr;
+			tb->fast_ipv6_only = ipv6_only_sock(sk);
+			tb->fast_sk_family = sk->sk_family;
+#if IS_ENABLED(CONFIG_IPV6)
+			tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
+#endif
+		} else {
+			tb->fastreuseport = 0;
+		}
+	} else {
+		if (!reuse)
+			tb->fastreuse = 0;
+		if (sk->sk_reuseport) {
+			/* We didn't match or we don't have fastreuseport set on
+			 * the tb, but we have sk_reuseport set on this socket
+			 * and we know that there are no bind conflicts with
+			 * this socket in this tb, so reset our tb's reuseport
+			 * settings so that any subsequent sockets that match
+			 * our current socket will be put on the fast path.
+			 *
+			 * If we reset we need to set FASTREUSEPORT_STRICT so we
+			 * do extra checking for all subsequent sk_reuseport
+			 * socks.
+			 */
+			if (!sk_reuseport_match(tb, sk)) {
+				tb->fastreuseport = FASTREUSEPORT_STRICT;
+				tb->fastuid = sk_uid(sk);
+				tb->fast_rcv_saddr = sk->sk_rcv_saddr;
+				tb->fast_ipv6_only = ipv6_only_sock(sk);
+				tb->fast_sk_family = sk->sk_family;
+#if IS_ENABLED(CONFIG_IPV6)
+				tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
+#endif
 			}
+		} else {
+			tb->fastreuseport = 0;
 		}
 	}
-	return sk2 != NULL;
+
+	tb2->fastreuse = tb->fastreuse;
+	tb2->fastreuseport = tb->fastreuseport;
 }
-EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
 
 /* Obtain a reference to a local port for the given sock,
  * if snum is zero it means select any available local port.
+ * We try to allocate an odd port (and leave even ports for connect())
  */
 int inet_csk_get_port(struct sock *sk, unsigned short snum)
 {
-	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-	struct inet_bind_hashbucket *head;
-	struct inet_bind_bucket *tb;
-	int ret, attempts = 5;
+	bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
+	bool found_port = false, check_bind_conflict = true;
+	bool bhash_created = false, bhash2_created = false;
+	struct inet_hashinfo *hinfo = tcp_get_hashinfo(sk);
+	int ret = -EADDRINUSE, port = snum, l3mdev;
+	struct inet_bind_hashbucket *head, *head2;
+	struct inet_bind2_bucket *tb2 = NULL;
+	struct inet_bind_bucket *tb = NULL;
+	bool head2_lock_acquired = false;
 	struct net *net = sock_net(sk);
-	int smallest_size = -1, smallest_rover;
-	kuid_t uid = sock_i_uid(sk);
-
-	local_bh_disable();
-	if (!snum) {
-		int remaining, rover, low, high;
-
-again:
-		inet_get_local_port_range(&low, &high);
-		remaining = (high - low) + 1;
-		smallest_rover = rover = net_random() % remaining + low;
-
-		smallest_size = -1;
-		do {
-			if (inet_is_reserved_local_port(rover))
-				goto next_nolock;
-			head = &hashinfo->bhash[inet_bhashfn(net, rover,
-					hashinfo->bhash_size)];
-			spin_lock(&head->lock);
-			inet_bind_bucket_for_each(tb, &head->chain)
-				if (net_eq(ib_net(tb), net) && tb->port == rover) {
-					if (((tb->fastreuse > 0 &&
-					      sk->sk_reuse &&
-					      sk->sk_state != TCP_LISTEN) ||
-					     (tb->fastreuseport > 0 &&
-					      sk->sk_reuseport &&
-					      uid_eq(tb->fastuid, uid))) &&
-					    (tb->num_owners < smallest_size || smallest_size == -1)) {
-						smallest_size = tb->num_owners;
-						smallest_rover = rover;
-						if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&
-						    !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
-							snum = smallest_rover;
-							goto tb_found;
-						}
-					}
-					if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
-						snum = rover;
-						goto tb_found;
-					}
-					goto next;
-				}
-			break;
-		next:
-			spin_unlock(&head->lock);
-		next_nolock:
-			if (++rover > high)
-				rover = low;
-		} while (--remaining > 0);
-
-		/* Exhausted local port range during search?  It is not
-		 * possible for us to be holding one of the bind hash
-		 * locks if this test triggers, because if 'remaining'
-		 * drops to zero, we broke out of the do/while loop at
-		 * the top level, not from the 'break;' statement.
-		 */
-		ret = 1;
-		if (remaining <= 0) {
-			if (smallest_size != -1) {
-				snum = smallest_rover;
-				goto have_snum;
-			}
-			goto fail;
-		}
-		/* OK, here is the one we will use.  HEAD is
-		 * non-NULL and we hold it's mutex.
-		 */
-		snum = rover;
+
+	l3mdev = inet_sk_bound_l3mdev(sk);
+
+	if (!port) {
+		head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port);
+		if (!head)
+			return ret;
+
+		head2_lock_acquired = true;
+
+		if (tb && tb2)
+			goto success;
+		found_port = true;
 	} else {
-have_snum:
-		head = &hashinfo->bhash[inet_bhashfn(net, snum,
-				hashinfo->bhash_size)];
-		spin_lock(&head->lock);
+		head = &hinfo->bhash[inet_bhashfn(net, port,
+						  hinfo->bhash_size)];
+		spin_lock_bh(&head->lock);
 		inet_bind_bucket_for_each(tb, &head->chain)
-			if (net_eq(ib_net(tb), net) && tb->port == snum)
-				goto tb_found;
-	}
-	tb = NULL;
-	goto tb_not_found;
-tb_found:
-	if (!hlist_empty(&tb->owners)) {
-		if (sk->sk_reuse == SK_FORCE_REUSE)
-			goto success;
+			if (inet_bind_bucket_match(tb, net, port, l3mdev))
+				break;
+	}
 
-		if (((tb->fastreuse > 0 &&
-		      sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
-		     (tb->fastreuseport > 0 &&
-		      sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
-		    smallest_size == -1) {
-			goto success;
-		} else {
-			ret = 1;
-			if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
-				if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
-				     (tb->fastreuseport > 0 &&
-				      sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
-				    smallest_size != -1 && --attempts >= 0) {
-					spin_unlock(&head->lock);
-					goto again;
-				}
+	if (!tb) {
+		tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net,
+					     head, port, l3mdev);
+		if (!tb)
+			goto fail_unlock;
+		bhash_created = true;
+	}
 
+	if (!found_port) {
+		if (!hlist_empty(&tb->bhash2)) {
+			if (sk->sk_reuse == SK_FORCE_REUSE ||
+			    (tb->fastreuse > 0 && reuse) ||
+			    sk_reuseport_match(tb, sk))
+				check_bind_conflict = false;
+		}
+
+		if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) {
+			if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true))
 				goto fail_unlock;
-			}
 		}
+
+		head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
+		spin_lock(&head2->lock);
+		head2_lock_acquired = true;
+		tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
 	}
-tb_not_found:
-	ret = 1;
-	if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
-					net, head, snum)) == NULL)
-		goto fail_unlock;
-	if (hlist_empty(&tb->owners)) {
-		if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
-			tb->fastreuse = 1;
-		else
-			tb->fastreuse = 0;
-		if (sk->sk_reuseport) {
-			tb->fastreuseport = 1;
-			tb->fastuid = uid;
-		} else
-			tb->fastreuseport = 0;
-	} else {
-		if (tb->fastreuse &&
-		    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
-			tb->fastreuse = 0;
-		if (tb->fastreuseport &&
-		    (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid)))
-			tb->fastreuseport = 0;
+
+	if (!tb2) {
+		tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
+					       net, head2, tb, sk);
+		if (!tb2)
+			goto fail_unlock;
+		bhash2_created = true;
 	}
+
+	if (!found_port && check_bind_conflict) {
+		if (inet_csk_bind_conflict(sk, tb, tb2, true, true))
+			goto fail_unlock;
+	}
+
 success:
+	inet_csk_update_fastreuse(sk, tb, tb2);
+
 	if (!inet_csk(sk)->icsk_bind_hash)
-		inet_bind_hash(sk, tb, snum);
+		inet_bind_hash(sk, tb, tb2, port);
 	WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
+	WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2);
 	ret = 0;
 
 fail_unlock:
-	spin_unlock(&head->lock);
-fail:
-	local_bh_enable();
+	if (ret) {
+		if (bhash2_created)
+			inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, tb2);
+		if (bhash_created)
+			inet_bind_bucket_destroy(tb);
+	}
+	if (head2_lock_acquired)
+		spin_unlock(&head2->lock);
+	spin_unlock_bh(&head->lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(inet_csk_get_port);
@@ -280,6 +638,7 @@ static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
 		release_sock(sk);
 		if (reqsk_queue_empty(&icsk->icsk_accept_queue))
 			timeo = schedule_timeout(timeo);
+		sched_annotate_sleep();
 		lock_sock(sk);
 		err = 0;
 		if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
@@ -301,12 +660,12 @@ static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
 /*
  * This will accept the next outstanding connection.
  */
-struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
+struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
-	struct sock *newsk;
 	struct request_sock *req;
+	struct sock *newsk;
 	int error;
 
 	lock_sock(sk);
@@ -320,7 +679,7 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
 
 	/* Find already established connection */
 	if (reqsk_queue_empty(queue)) {
-		long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+		long timeo = sock_rcvtimeo(sk, arg->flags & O_NONBLOCK);
 
 		/* If this is a non blocking socket don't sleep */
 		error = -EAGAIN;
@@ -331,13 +690,14 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
 		if (error)
 			goto out_err;
 	}
-	req = reqsk_queue_remove(queue);
+	req = reqsk_queue_remove(queue, sk);
+	arg->is_empty = reqsk_queue_empty(queue);
 	newsk = req->sk;
 
-	sk_acceptq_removed(sk);
-	if (sk->sk_protocol == IPPROTO_TCP && queue->fastopenq != NULL) {
-		spin_lock_bh(&queue->fastopenq->lock);
-		if (tcp_rsk(req)->listener) {
+	if (sk->sk_protocol == IPPROTO_TCP &&
+	    tcp_rsk(req)->tfo_listener) {
+		spin_lock_bh(&queue->fastopenq.lock);
+		if (tcp_rsk(req)->tfo_listener) {
 			/* We are still waiting for the final ACK from 3WHS
 			 * so can't free req now. Instead, we set req->sk to
 			 * NULL to signify that the child socket is taken
@@ -347,18 +707,21 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
 			req->sk = NULL;
 			req = NULL;
 		}
-		spin_unlock_bh(&queue->fastopenq->lock);
+		spin_unlock_bh(&queue->fastopenq.lock);
 	}
-out:
+
 	release_sock(sk);
+
 	if (req)
-		__reqsk_free(req);
+		reqsk_put(req);
+
+	inet_init_csk_locks(newsk);
 	return newsk;
+
 out_err:
-	newsk = NULL;
-	req = NULL;
-	*err = error;
-	goto out;
+	release_sock(sk);
+	arg->err = error;
+	return NULL;
 }
 EXPORT_SYMBOL(inet_csk_accept);
 
@@ -368,222 +731,340 @@ EXPORT_SYMBOL(inet_csk_accept);
  * to optimize.
  */
 void inet_csk_init_xmit_timers(struct sock *sk,
-			       void (*retransmit_handler)(unsigned long),
-			       void (*delack_handler)(unsigned long),
-			       void (*keepalive_handler)(unsigned long))
+			       void (*retransmit_handler)(struct timer_list *t),
+			       void (*delack_handler)(struct timer_list *t),
+			       void (*keepalive_handler)(struct timer_list *t))
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
-	setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
-			(unsigned long)sk);
-	setup_timer(&icsk->icsk_delack_timer, delack_handler,
-			(unsigned long)sk);
-	setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
+	timer_setup(&sk->tcp_retransmit_timer, retransmit_handler, 0);
+	timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
+	timer_setup(&icsk->icsk_keepalive_timer, keepalive_handler, 0);
 	icsk->icsk_pending = icsk->icsk_ack.pending = 0;
 }
-EXPORT_SYMBOL(inet_csk_init_xmit_timers);
 
 void inet_csk_clear_xmit_timers(struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
-	icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
+	smp_store_release(&icsk->icsk_pending, 0);
+	smp_store_release(&icsk->icsk_ack.pending, 0);
 
-	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
+	sk_stop_timer(sk, &sk->tcp_retransmit_timer);
 	sk_stop_timer(sk, &icsk->icsk_delack_timer);
-	sk_stop_timer(sk, &sk->sk_timer);
+	sk_stop_timer(sk, &icsk->icsk_keepalive_timer);
 }
-EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
 
-void inet_csk_delete_keepalive_timer(struct sock *sk)
+void inet_csk_clear_xmit_timers_sync(struct sock *sk)
 {
-	sk_stop_timer(sk, &sk->sk_timer);
-}
-EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
+	struct inet_connection_sock *icsk = inet_csk(sk);
 
-void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
-{
-	sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
+	/* ongoing timer handlers need to acquire socket lock. */
+	sock_not_owned_by_me(sk);
+
+	smp_store_release(&icsk->icsk_pending, 0);
+	smp_store_release(&icsk->icsk_ack.pending, 0);
+
+	sk_stop_timer_sync(sk, &sk->tcp_retransmit_timer);
+	sk_stop_timer_sync(sk, &icsk->icsk_delack_timer);
+	sk_stop_timer_sync(sk, &icsk->icsk_keepalive_timer);
 }
-EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
 
-struct dst_entry *inet_csk_route_req(struct sock *sk,
+struct dst_entry *inet_csk_route_req(const struct sock *sk,
 				     struct flowi4 *fl4,
 				     const struct request_sock *req)
 {
-	struct rtable *rt;
 	const struct inet_request_sock *ireq = inet_rsk(req);
-	struct ip_options_rcu *opt = inet_rsk(req)->opt;
-	struct net *net = sock_net(sk);
-	int flags = inet_sk_flowi_flags(sk);
-
-	flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
-			   RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
-			   sk->sk_protocol,
-			   flags,
-			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
-			   ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
-	security_req_classify_flow(req, flowi4_to_flowi(fl4));
+	struct net *net = read_pnet(&ireq->ireq_net);
+	struct ip_options_rcu *opt;
+	struct rtable *rt;
+
+	rcu_read_lock();
+	opt = rcu_dereference(ireq->ireq_opt);
+
+	flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
+			   ip_sock_rt_tos(sk), ip_sock_rt_scope(sk),
+			   sk->sk_protocol, inet_sk_flowi_flags(sk),
+			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
+			   ireq->ir_loc_addr, ireq->ir_rmt_port,
+			   htons(ireq->ir_num), sk_uid(sk));
+	security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
 	rt = ip_route_output_flow(net, fl4, sk);
 	if (IS_ERR(rt))
 		goto no_route;
 	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
 		goto route_err;
+	rcu_read_unlock();
 	return &rt->dst;
 
 route_err:
 	ip_rt_put(rt);
 no_route:
-	IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+	rcu_read_unlock();
+	__IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(inet_csk_route_req);
 
-struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
+struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 					    struct sock *newsk,
 					    const struct request_sock *req)
 {
 	const struct inet_request_sock *ireq = inet_rsk(req);
+	struct net *net = read_pnet(&ireq->ireq_net);
 	struct inet_sock *newinet = inet_sk(newsk);
 	struct ip_options_rcu *opt;
-	struct net *net = sock_net(sk);
 	struct flowi4 *fl4;
 	struct rtable *rt;
 
+	opt = rcu_dereference(ireq->ireq_opt);
 	fl4 = &newinet->cork.fl.u.ip4;
 
-	rcu_read_lock();
-	opt = rcu_dereference(newinet->inet_opt);
-	flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
-			   RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
+	flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
+			   ip_sock_rt_tos(sk), ip_sock_rt_scope(sk),
 			   sk->sk_protocol, inet_sk_flowi_flags(sk),
-			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
-			   ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
-	security_req_classify_flow(req, flowi4_to_flowi(fl4));
+			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
+			   ireq->ir_loc_addr, ireq->ir_rmt_port,
+			   htons(ireq->ir_num), sk_uid(sk));
+	security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
 	rt = ip_route_output_flow(net, fl4, sk);
 	if (IS_ERR(rt))
 		goto no_route;
 	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
 		goto route_err;
-	rcu_read_unlock();
 	return &rt->dst;
 
 route_err:
 	ip_rt_put(rt);
 no_route:
-	rcu_read_unlock();
-	IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+	__IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
 
-static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
-				 const u32 rnd, const u32 synq_hsize)
+/* Decide when to expire the request and when to resend SYN-ACK */
+static void syn_ack_recalc(struct request_sock *req,
+			   const int max_syn_ack_retries,
+			   const u8 rskq_defer_accept,
+			   int *expire, int *resend)
+{
+	if (!rskq_defer_accept) {
+		*expire = req->num_timeout >= max_syn_ack_retries;
+		*resend = 1;
+		return;
+	}
+	*expire = req->num_timeout >= max_syn_ack_retries &&
+		  (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
+	/* Do not resend while waiting for data after ACK,
+	 * start to resend on end of deferring period to give
+	 * last chance for data or ACK to create established socket.
+	 */
+	*resend = !inet_rsk(req)->acked ||
+		  req->num_timeout >= rskq_defer_accept - 1;
+}
+
+static struct request_sock *
+reqsk_alloc_noprof(const struct request_sock_ops *ops, struct sock *sk_listener,
+		   bool attach_listener)
 {
-	return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
+	struct request_sock *req;
+
+	req = kmem_cache_alloc_noprof(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
+	if (!req)
+		return NULL;
+	req->rsk_listener = NULL;
+	if (attach_listener) {
+		if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) {
+			kmem_cache_free(ops->slab, req);
+			return NULL;
+		}
+		req->rsk_listener = sk_listener;
+	}
+	req->rsk_ops = ops;
+	req_to_sk(req)->sk_prot = sk_listener->sk_prot;
+	sk_node_init(&req_to_sk(req)->sk_node);
+	sk_tx_queue_clear(req_to_sk(req));
+	req->saved_syn = NULL;
+	req->syncookie = 0;
+	req->num_timeout = 0;
+	req->num_retrans = 0;
+	req->sk = NULL;
+	refcount_set(&req->rsk_refcnt, 0);
+
+	return req;
 }
+#define reqsk_alloc(...)	alloc_hooks(reqsk_alloc_noprof(__VA_ARGS__))
+
+struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
+				      struct sock *sk_listener,
+				      bool attach_listener)
+{
+	struct request_sock *req = reqsk_alloc(ops, sk_listener,
+					       attach_listener);
+
+	if (req) {
+		struct inet_request_sock *ireq = inet_rsk(req);
 
+		ireq->ireq_opt = NULL;
 #if IS_ENABLED(CONFIG_IPV6)
-#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
-#else
-#define AF_INET_FAMILY(fam) 1
+		ireq->pktopts = NULL;
 #endif
+		atomic64_set(&ireq->ir_cookie, 0);
+		ireq->ireq_state = TCP_NEW_SYN_RECV;
+		write_pnet(&ireq->ireq_net, sock_net(sk_listener));
+		ireq->ireq_family = sk_listener->sk_family;
+	}
+
+	return req;
+}
+EXPORT_SYMBOL(inet_reqsk_alloc);
 
-struct request_sock *inet_csk_search_req(const struct sock *sk,
-					 struct request_sock ***prevp,
-					 const __be16 rport, const __be32 raddr,
-					 const __be32 laddr)
+static struct request_sock *inet_reqsk_clone(struct request_sock *req,
+					     struct sock *sk)
 {
-	const struct inet_connection_sock *icsk = inet_csk(sk);
-	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
-	struct request_sock *req, **prev;
-
-	for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
-						    lopt->nr_table_entries)];
-	     (req = *prev) != NULL;
-	     prev = &req->dl_next) {
-		const struct inet_request_sock *ireq = inet_rsk(req);
-
-		if (ireq->rmt_port == rport &&
-		    ireq->rmt_addr == raddr &&
-		    ireq->loc_addr == laddr &&
-		    AF_INET_FAMILY(req->rsk_ops->family)) {
-			WARN_ON(req->sk);
-			*prevp = prev;
-			break;
-		}
+	struct sock *req_sk, *nreq_sk;
+	struct request_sock *nreq;
+
+	nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
+	if (!nreq) {
+		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
+
+		/* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
+		sock_put(sk);
+		return NULL;
 	}
 
-	return req;
+	req_sk = req_to_sk(req);
+	nreq_sk = req_to_sk(nreq);
+
+	memcpy(nreq_sk, req_sk,
+	       offsetof(struct sock, sk_dontcopy_begin));
+	unsafe_memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
+		      req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end),
+		      /* alloc is larger than struct, see above */);
+
+	sk_node_init(&nreq_sk->sk_node);
+	nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
+#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
+	nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
+#endif
+	nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
+
+	nreq->rsk_listener = sk;
+
+	/* We need not acquire fastopenq->lock
+	 * because the child socket is locked in inet_csk_listen_stop().
+	 */
+	if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener)
+		rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
+
+	return nreq;
 }
-EXPORT_SYMBOL_GPL(inet_csk_search_req);
 
-void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
-				   unsigned long timeout)
+static void reqsk_queue_migrated(struct request_sock_queue *queue,
+				 const struct request_sock *req)
 {
-	struct inet_connection_sock *icsk = inet_csk(sk);
-	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
-	const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
-				     lopt->hash_rnd, lopt->nr_table_entries);
+	if (req->num_timeout == 0)
+		atomic_inc(&queue->young);
+	atomic_inc(&queue->qlen);
+}
 
-	reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
-	inet_csk_reqsk_queue_added(sk, timeout);
+static void reqsk_migrate_reset(struct request_sock *req)
+{
+	req->saved_syn = NULL;
+#if IS_ENABLED(CONFIG_IPV6)
+	inet_rsk(req)->ipv6_opt = NULL;
+	inet_rsk(req)->pktopts = NULL;
+#else
+	inet_rsk(req)->ireq_opt = NULL;
+#endif
 }
-EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
 
-/* Only thing we need from tcp.h */
-extern int sysctl_tcp_synack_retries;
+/* return true if req was found in the ehash table */
+static bool reqsk_queue_unlink(struct request_sock *req)
+{
+	struct sock *sk = req_to_sk(req);
+	bool found = false;
+
+	if (sk_hashed(sk)) {
+		struct inet_hashinfo *hashinfo = tcp_get_hashinfo(sk);
+		spinlock_t *lock;
 
+		lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
+		spin_lock(lock);
+		found = __sk_nulls_del_node_init_rcu(sk);
+		spin_unlock(lock);
+	}
 
-/* Decide when to expire the request and when to resend SYN-ACK */
-static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
-				  const int max_retries,
-				  const u8 rskq_defer_accept,
-				  int *expire, int *resend)
+	return found;
+}
+
+static bool __inet_csk_reqsk_queue_drop(struct sock *sk,
+					struct request_sock *req,
+					bool from_timer)
 {
-	if (!rskq_defer_accept) {
-		*expire = req->num_timeout >= thresh;
-		*resend = 1;
-		return;
+	bool unlinked = reqsk_queue_unlink(req);
+
+	if (!from_timer && timer_delete_sync(&req->rsk_timer))
+		reqsk_put(req);
+
+	if (unlinked) {
+		reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
+		reqsk_put(req);
 	}
-	*expire = req->num_timeout >= thresh &&
-		  (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
-	/*
-	 * Do not resend while waiting for data after ACK,
-	 * start to resend on end of deferring period to give
-	 * last chance for data or ACK to create established socket.
-	 */
-	*resend = !inet_rsk(req)->acked ||
-		  req->num_timeout >= rskq_defer_accept - 1;
+
+	return unlinked;
 }
 
-int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req)
+bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
 {
-	int err = req->rsk_ops->rtx_syn_ack(parent, req);
+	return __inet_csk_reqsk_queue_drop(sk, req, false);
+}
 
-	if (!err)
-		req->num_retrans++;
-	return err;
+void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
+{
+	inet_csk_reqsk_queue_drop(sk, req);
+	reqsk_put(req);
 }
-EXPORT_SYMBOL(inet_rtx_syn_ack);
+EXPORT_IPV6_MOD(inet_csk_reqsk_queue_drop_and_put);
 
-void inet_csk_reqsk_queue_prune(struct sock *parent,
-				const unsigned long interval,
-				const unsigned long timeout,
-				const unsigned long max_rto)
+static void reqsk_timer_handler(struct timer_list *t)
 {
-	struct inet_connection_sock *icsk = inet_csk(parent);
-	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
-	struct listen_sock *lopt = queue->listen_opt;
-	int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
-	int thresh = max_retries;
-	unsigned long now = jiffies;
-	struct request_sock **reqp, *req;
-	int i, budget;
-
-	if (lopt == NULL || lopt->qlen == 0)
-		return;
+	struct request_sock *req = timer_container_of(req, t, rsk_timer);
+	struct request_sock *nreq = NULL, *oreq = req;
+	struct sock *sk_listener = req->rsk_listener;
+	struct inet_connection_sock *icsk;
+	struct request_sock_queue *queue;
+	struct net *net;
+	int max_syn_ack_retries, qlen, expire = 0, resend = 0;
+
+	if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {
+		struct sock *nsk;
+
+		nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL);
+		if (!nsk)
+			goto drop;
+
+		nreq = inet_reqsk_clone(req, nsk);
+		if (!nreq)
+			goto drop;
+
+		/* The new timer for the cloned req can decrease the 2
+		 * by calling inet_csk_reqsk_queue_drop_and_put(), so
+		 * hold another count to prevent use-after-free and
+		 * call reqsk_put() just before return.
+		 */
+		refcount_set(&nreq->rsk_refcnt, 2 + 1);
+		timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
+		reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req);
+
+		req = nreq;
+		sk_listener = nsk;
+	}
 
+	icsk = inet_csk(sk_listener);
+	net = sock_net(sk_listener);
+	max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? :
+		READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);
 	/* Normally all the openreqs are young and become mature
 	 * (i.e. converted to established socket) for first timeout.
 	 * If synack was not acknowledged for 1 second, it means
@@ -601,67 +1082,105 @@ void inet_csk_reqsk_queue_prune(struct sock *parent,
 	 * embrions; and abort old ones without pity, if old
 	 * ones are about to clog our table.
 	 */
-	if (lopt->qlen>>(lopt->max_qlen_log-1)) {
-		int young = (lopt->qlen_young<<1);
+	queue = &icsk->icsk_accept_queue;
+	qlen = reqsk_queue_len(queue);
+	if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
+		int young = reqsk_queue_len_young(queue) << 1;
 
-		while (thresh > 2) {
-			if (lopt->qlen < young)
+		while (max_syn_ack_retries > 2) {
+			if (qlen < young)
 				break;
-			thresh--;
+			max_syn_ack_retries--;
 			young <<= 1;
 		}
 	}
 
-	if (queue->rskq_defer_accept)
-		max_retries = queue->rskq_defer_accept;
-
-	budget = 2 * (lopt->nr_table_entries / (timeout / interval));
-	i = lopt->clock_hand;
-
-	do {
-		reqp=&lopt->syn_table[i];
-		while ((req = *reqp) != NULL) {
-			if (time_after_eq(now, req->expires)) {
-				int expire = 0, resend = 0;
-
-				syn_ack_recalc(req, thresh, max_retries,
-					       queue->rskq_defer_accept,
-					       &expire, &resend);
-				req->rsk_ops->syn_ack_timeout(parent, req);
-				if (!expire &&
-				    (!resend ||
-				     !inet_rtx_syn_ack(parent, req) ||
-				     inet_rsk(req)->acked)) {
-					unsigned long timeo;
-
-					if (req->num_timeout++ == 0)
-						lopt->qlen_young--;
-					timeo = min(timeout << req->num_timeout,
-						    max_rto);
-					req->expires = now + timeo;
-					reqp = &req->dl_next;
-					continue;
-				}
-
-				/* Drop this request */
-				inet_csk_reqsk_queue_unlink(parent, req, reqp);
-				reqsk_queue_removed(queue, req);
-				reqsk_free(req);
-				continue;
-			}
-			reqp = &req->dl_next;
+	syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
+		       &expire, &resend);
+	tcp_syn_ack_timeout(req);
+
+	if (!expire &&
+	    (!resend ||
+	     !tcp_rtx_synack(sk_listener, req) ||
+	     inet_rsk(req)->acked)) {
+		if (req->num_timeout++ == 0)
+			atomic_dec(&queue->young);
+		mod_timer(&req->rsk_timer, jiffies + tcp_reqsk_timeout(req));
+
+		if (!nreq)
+			return;
+
+		if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) {
+			/* delete timer */
+			__inet_csk_reqsk_queue_drop(sk_listener, nreq, true);
+			goto no_ownership;
 		}
 
-		i = (i + 1) & (lopt->nr_table_entries - 1);
+		__NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
+		reqsk_migrate_reset(oreq);
+		reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq);
+		reqsk_put(oreq);
+
+		reqsk_put(nreq);
+		return;
+	}
+
+	/* Even if we can clone the req, we may need not retransmit any more
+	 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
+	 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
+	 */
+	if (nreq) {
+		__NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
+no_ownership:
+		reqsk_migrate_reset(nreq);
+		reqsk_queue_removed(queue, nreq);
+		__reqsk_free(nreq);
+	}
+
+drop:
+	__inet_csk_reqsk_queue_drop(sk_listener, oreq, true);
+	reqsk_put(oreq);
+}
+
+static bool reqsk_queue_hash_req(struct request_sock *req)
+{
+	bool found_dup_sk = false;
+
+	if (!inet_ehash_insert(req_to_sk(req), NULL, &found_dup_sk))
+		return false;
+
+	/* The timer needs to be setup after a successful insertion. */
+	req->timeout = tcp_timeout_init((struct sock *)req);
+	timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
+	mod_timer(&req->rsk_timer, jiffies + req->timeout);
+
+	/* before letting lookups find us, make sure all req fields
+	 * are committed to memory and refcnt initialized.
+	 */
+	smp_wmb();
+	refcount_set(&req->rsk_refcnt, 2 + 1);
+	return true;
+}
+
+bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req)
+{
+	if (!reqsk_queue_hash_req(req))
+		return false;
+
+	inet_csk_reqsk_queue_added(sk);
+	return true;
+}
 
-	} while (--budget > 0);
+static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
+			   const gfp_t priority)
+{
+	struct inet_connection_sock *icsk = inet_csk(newsk);
 
-	lopt->clock_hand = i;
+	if (!icsk->icsk_ulp_ops)
+		return;
 
-	if (lopt->qlen)
-		inet_csk_reset_keepalive_timer(parent, interval);
+	icsk->icsk_ulp_ops->clone(req, newsk, priority);
 }
-EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
 
 /**
  *	inet_csk_clone_lock - clone an inet socket, and lock its clone
@@ -676,30 +1195,61 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
 				 const gfp_t priority)
 {
 	struct sock *newsk = sk_clone_lock(sk, priority);
+	struct inet_connection_sock *newicsk;
+	struct inet_request_sock *ireq;
+	struct inet_sock *newinet;
 
-	if (newsk != NULL) {
-		struct inet_connection_sock *newicsk = inet_csk(newsk);
+	if (!newsk)
+		return NULL;
 
-		newsk->sk_state = TCP_SYN_RECV;
-		newicsk->icsk_bind_hash = NULL;
+	newicsk = inet_csk(newsk);
+	newinet = inet_sk(newsk);
+	ireq = inet_rsk(req);
 
-		inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
-		inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
-		inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
-		newsk->sk_write_space = sk_stream_write_space;
+	newicsk->icsk_bind_hash = NULL;
+	newicsk->icsk_bind2_hash = NULL;
 
-		newicsk->icsk_retransmits = 0;
-		newicsk->icsk_backoff	  = 0;
-		newicsk->icsk_probes_out  = 0;
+	newinet->inet_dport = ireq->ir_rmt_port;
+	newinet->inet_num = ireq->ir_num;
+	newinet->inet_sport = htons(ireq->ir_num);
 
-		/* Deinitialize accept_queue to trap illegal accesses. */
-		memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
+	newsk->sk_bound_dev_if = ireq->ir_iif;
+
+	newsk->sk_daddr = ireq->ir_rmt_addr;
+	newsk->sk_rcv_saddr = ireq->ir_loc_addr;
+	newinet->inet_saddr = ireq->ir_loc_addr;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
+	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
+#endif
+
+	/* listeners have SOCK_RCU_FREE, not the children */
+	sock_reset_flag(newsk, SOCK_RCU_FREE);
+
+	inet_sk(newsk)->mc_list = NULL;
+
+	newsk->sk_mark = inet_rsk(req)->ir_mark;
+	atomic64_set(&newsk->sk_cookie,
+		     atomic64_read(&inet_rsk(req)->ir_cookie));
+
+	newicsk->icsk_retransmits = 0;
+	newicsk->icsk_backoff	  = 0;
+	newicsk->icsk_probes_out  = 0;
+	newicsk->icsk_probes_tstamp = 0;
+
+	/* Deinitialize accept_queue to trap illegal accesses. */
+	memset(&newicsk->icsk_accept_queue, 0,
+	       sizeof(newicsk->icsk_accept_queue));
+
+	inet_sk_set_state(newsk, TCP_SYN_RECV);
+
+	inet_clone_ulp(req, newsk, priority);
+
+	security_inet_csk_clone(newsk, req);
 
-		security_inet_csk_clone(newsk, req);
-	}
 	return newsk;
 }
-EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
 
 /*
  * At this point, there should be no process reference to this
@@ -724,15 +1274,21 @@ void inet_csk_destroy_sock(struct sock *sk)
 
 	xfrm_sk_free_policy(sk);
 
-	sk_refcnt_debug_release(sk);
+	tcp_orphan_count_dec();
 
-	percpu_counter_dec(sk->sk_prot->orphan_count);
 	sock_put(sk);
 }
 EXPORT_SYMBOL(inet_csk_destroy_sock);
 
+void inet_csk_prepare_for_destroy_sock(struct sock *sk)
+{
+	/* The below has to be done to allow calling inet_csk_destroy_sock */
+	sock_set_flag(sk, SOCK_DEAD);
+	tcp_orphan_count_inc();
+}
+
 /* This function allows to force a closure of a socket after the call to
- * tcp/dccp_create_openreq_child().
+ * tcp_create_openreq_child().
  */
 void inet_csk_prepare_forced_close(struct sock *sk)
 	__releases(&sk->sk_lock.slock)
@@ -740,24 +1296,33 @@ void inet_csk_prepare_forced_close(struct sock *sk)
 	/* sk_clone_lock locked the socket and set refcnt to 2 */
 	bh_unlock_sock(sk);
 	sock_put(sk);
-
-	/* The below has to be done to allow calling inet_csk_destroy_sock */
-	sock_set_flag(sk, SOCK_DEAD);
-	percpu_counter_inc(sk->sk_prot->orphan_count);
+	inet_csk_prepare_for_destroy_sock(sk);
 	inet_sk(sk)->inet_num = 0;
 }
 EXPORT_SYMBOL(inet_csk_prepare_forced_close);
 
-int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
+static int inet_ulp_can_listen(const struct sock *sk)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
+		return -EINVAL;
+
+	return 0;
+}
+
+int inet_csk_listen_start(struct sock *sk)
 {
-	struct inet_sock *inet = inet_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
-	int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
+	struct inet_sock *inet = inet_sk(sk);
+	int err;
+
+	err = inet_ulp_can_listen(sk);
+	if (unlikely(err))
+		return err;
 
-	if (rc != 0)
-		return rc;
+	reqsk_queue_alloc(&icsk->icsk_accept_queue);
 
-	sk->sk_max_ack_backlog = 0;
 	sk->sk_ack_backlog = 0;
 	inet_csk_delack_init(sk);
 
@@ -766,21 +1331,115 @@ int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
 	 * It is OK, because this socket enters to hash table only
 	 * after validation is complete.
 	 */
-	sk->sk_state = TCP_LISTEN;
-	if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
+	inet_sk_state_store(sk, TCP_LISTEN);
+	err = sk->sk_prot->get_port(sk, inet->inet_num);
+	if (!err) {
 		inet->inet_sport = htons(inet->inet_num);
 
 		sk_dst_reset(sk);
-		sk->sk_prot->hash(sk);
+		err = sk->sk_prot->hash(sk);
 
-		return 0;
+		if (likely(!err))
+			return 0;
 	}
 
-	sk->sk_state = TCP_CLOSE;
-	__reqsk_queue_destroy(&icsk->icsk_accept_queue);
-	return -EADDRINUSE;
+	inet_sk_set_state(sk, TCP_CLOSE);
+	return err;
+}
+
+static void inet_child_forget(struct sock *sk, struct request_sock *req,
+			      struct sock *child)
+{
+	sk->sk_prot->disconnect(child, O_NONBLOCK);
+
+	sock_orphan(child);
+
+	tcp_orphan_count_inc();
+
+	if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
+		BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
+		BUG_ON(sk != req->rsk_listener);
+
+		/* Paranoid, to prevent race condition if
+		 * an inbound pkt destined for child is
+		 * blocked by sock lock in tcp_v4_rcv().
+		 * Also to satisfy an assertion in
+		 * tcp_v4_destroy_sock().
+		 */
+		RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
+	}
+	inet_csk_destroy_sock(child);
+}
+
+struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
+				      struct request_sock *req,
+				      struct sock *child)
+{
+	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
+
+	spin_lock(&queue->rskq_lock);
+	if (unlikely(sk->sk_state != TCP_LISTEN)) {
+		inet_child_forget(sk, req, child);
+		child = NULL;
+	} else {
+		req->sk = child;
+		req->dl_next = NULL;
+		if (queue->rskq_accept_head == NULL)
+			WRITE_ONCE(queue->rskq_accept_head, req);
+		else
+			queue->rskq_accept_tail->dl_next = req;
+		queue->rskq_accept_tail = req;
+		sk_acceptq_added(sk);
+	}
+	spin_unlock(&queue->rskq_lock);
+	return child;
+}
+EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
+
+struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
+					 struct request_sock *req, bool own_req)
+{
+	if (own_req) {
+		inet_csk_reqsk_queue_drop(req->rsk_listener, req);
+		reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req);
+
+		if (sk != req->rsk_listener) {
+			/* another listening sk has been selected,
+			 * migrate the req to it.
+			 */
+			struct request_sock *nreq;
+
+			/* hold a refcnt for the nreq->rsk_listener
+			 * which is assigned in inet_reqsk_clone()
+			 */
+			sock_hold(sk);
+			nreq = inet_reqsk_clone(req, sk);
+			if (!nreq) {
+				inet_child_forget(sk, req, child);
+				goto child_put;
+			}
+
+			refcount_set(&nreq->rsk_refcnt, 1);
+			if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
+				__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
+				reqsk_migrate_reset(req);
+				reqsk_put(req);
+				return child;
+			}
+
+			__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
+			reqsk_migrate_reset(nreq);
+			__reqsk_free(nreq);
+		} else if (inet_csk_reqsk_queue_add(sk, req, child)) {
+			return child;
+		}
+	}
+	/* Too bad, another child took ownership of the request, undo. */
+child_put:
+	bh_unlock_sock(child);
+	sock_put(child);
+	return NULL;
 }
-EXPORT_SYMBOL_GPL(inet_csk_listen_start);
 
 /*
  *	This routine closes sockets which have been at least partially
@@ -790,13 +1449,7 @@ void inet_csk_listen_stop(struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
-	struct request_sock *acc_req;
-	struct request_sock *req;
-
-	inet_csk_delete_keepalive_timer(sk);
-
-	/* make all the listen_opt local to us */
-	acc_req = reqsk_queue_yank_acceptq(queue);
+	struct request_sock *next, *req;
 
 	/* Following specs, it would be better either to send FIN
 	 * (and enter FIN-WAIT-1, it is normal close)
@@ -806,117 +1459,74 @@ void inet_csk_listen_stop(struct sock *sk)
 	 * To be honest, we are not able to make either
 	 * of the variants now.			--ANK
 	 */
-	reqsk_queue_destroy(queue);
-
-	while ((req = acc_req) != NULL) {
-		struct sock *child = req->sk;
-
-		acc_req = req->dl_next;
+	while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
+		struct sock *child = req->sk, *nsk;
+		struct request_sock *nreq;
 
 		local_bh_disable();
 		bh_lock_sock(child);
 		WARN_ON(sock_owned_by_user(child));
 		sock_hold(child);
 
-		sk->sk_prot->disconnect(child, O_NONBLOCK);
-
-		sock_orphan(child);
-
-		percpu_counter_inc(sk->sk_prot->orphan_count);
-
-		if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->listener) {
-			BUG_ON(tcp_sk(child)->fastopen_rsk != req);
-			BUG_ON(sk != tcp_rsk(req)->listener);
+		nsk = reuseport_migrate_sock(sk, child, NULL);
+		if (nsk) {
+			nreq = inet_reqsk_clone(req, nsk);
+			if (nreq) {
+				refcount_set(&nreq->rsk_refcnt, 1);
+
+				if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
+					__NET_INC_STATS(sock_net(nsk),
+							LINUX_MIB_TCPMIGRATEREQSUCCESS);
+					reqsk_migrate_reset(req);
+				} else {
+					__NET_INC_STATS(sock_net(nsk),
+							LINUX_MIB_TCPMIGRATEREQFAILURE);
+					reqsk_migrate_reset(nreq);
+					__reqsk_free(nreq);
+				}
 
-			/* Paranoid, to prevent race condition if
-			 * an inbound pkt destined for child is
-			 * blocked by sock lock in tcp_v4_rcv().
-			 * Also to satisfy an assertion in
-			 * tcp_v4_destroy_sock().
-			 */
-			tcp_sk(child)->fastopen_rsk = NULL;
-			sock_put(sk);
+				/* inet_csk_reqsk_queue_add() has already
+				 * called inet_child_forget() on failure case.
+				 */
+				goto skip_child_forget;
+			}
 		}
-		inet_csk_destroy_sock(child);
 
+		inet_child_forget(sk, req, child);
+skip_child_forget:
+		reqsk_put(req);
 		bh_unlock_sock(child);
 		local_bh_enable();
 		sock_put(child);
 
-		sk_acceptq_removed(sk);
-		__reqsk_free(req);
+		cond_resched();
 	}
-	if (queue->fastopenq != NULL) {
+	if (queue->fastopenq.rskq_rst_head) {
 		/* Free all the reqs queued in rskq_rst_head. */
-		spin_lock_bh(&queue->fastopenq->lock);
-		acc_req = queue->fastopenq->rskq_rst_head;
-		queue->fastopenq->rskq_rst_head = NULL;
-		spin_unlock_bh(&queue->fastopenq->lock);
-		while ((req = acc_req) != NULL) {
-			acc_req = req->dl_next;
-			__reqsk_free(req);
+		spin_lock_bh(&queue->fastopenq.lock);
+		req = queue->fastopenq.rskq_rst_head;
+		queue->fastopenq.rskq_rst_head = NULL;
+		spin_unlock_bh(&queue->fastopenq.lock);
+		while (req != NULL) {
+			next = req->dl_next;
+			reqsk_put(req);
+			req = next;
 		}
 	}
-	WARN_ON(sk->sk_ack_backlog);
+	WARN_ON_ONCE(sk->sk_ack_backlog);
 }
 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
 
-void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
-{
-	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
-	const struct inet_sock *inet = inet_sk(sk);
-
-	sin->sin_family		= AF_INET;
-	sin->sin_addr.s_addr	= inet->inet_daddr;
-	sin->sin_port		= inet->inet_dport;
-}
-EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
-
-#ifdef CONFIG_COMPAT
-int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
-			       char __user *optval, int __user *optlen)
-{
-	const struct inet_connection_sock *icsk = inet_csk(sk);
-
-	if (icsk->icsk_af_ops->compat_getsockopt != NULL)
-		return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
-							    optval, optlen);
-	return icsk->icsk_af_ops->getsockopt(sk, level, optname,
-					     optval, optlen);
-}
-EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
-
-int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
-			       char __user *optval, unsigned int optlen)
-{
-	const struct inet_connection_sock *icsk = inet_csk(sk);
-
-	if (icsk->icsk_af_ops->compat_setsockopt != NULL)
-		return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
-							    optval, optlen);
-	return icsk->icsk_af_ops->setsockopt(sk, level, optname,
-					     optval, optlen);
-}
-EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
-#endif
-
 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
 {
 	const struct inet_sock *inet = inet_sk(sk);
-	const struct ip_options_rcu *inet_opt;
-	__be32 daddr = inet->inet_daddr;
 	struct flowi4 *fl4;
 	struct rtable *rt;
 
 	rcu_read_lock();
-	inet_opt = rcu_dereference(inet->inet_opt);
-	if (inet_opt && inet_opt->opt.srr)
-		daddr = inet_opt->opt.faddr;
 	fl4 = &fl->u.ip4;
-	rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
-				   inet->inet_saddr, inet->inet_dport,
-				   inet->inet_sport, sk->sk_protocol,
-				   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
+	inet_sk_init_flowi4(inet, fl4);
+	rt = ip_route_output_flow(sock_net(sk), fl4, sk);
 	if (IS_ERR(rt))
 		rt = NULL;
 	if (rt)
@@ -936,7 +1546,7 @@ struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
 		if (!dst)
 			goto out;
 	}
-	dst->ops->update_pmtu(dst, sk, NULL, mtu);
+	dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
 
 	dst = __sk_dst_check(sk, 0);
 	if (!dst)
@@ -944,4 +1554,3 @@ struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
 out:
 	return dst;
 }
-EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);