1 files changed, 93 insertions, 72 deletions

diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index dd37a5bf6881..d4c781a0667f 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -15,7 +15,8 @@
 #include <net/inet_hashtables.h>
 #include <net/inet_timewait_sock.h>
 #include <net/ip.h>
-
+#include <net/tcp.h>
+#include <net/psp.h>
 
 /**
  *	inet_twsk_bind_unhash - unhash a timewait socket from bind hash
@@ -35,13 +36,11 @@ void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 	if (!tb)
 		return;
 
-	__hlist_del(&tw->tw_bind_node);
+	__sk_del_bind_node((struct sock *)tw);
 	tw->tw_tb = NULL;
-	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
-
-	__hlist_del(&tw->tw_bind2_node);
 	tw->tw_tb2 = NULL;
 	inet_bind2_bucket_destroy(hashinfo->bind2_bucket_cachep, tb2);
+	inet_bind_bucket_destroy(tb);
 
 	__sock_put((struct sock *)tw);
 }
@@ -76,7 +75,8 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
 void inet_twsk_free(struct inet_timewait_sock *tw)
 {
 	struct module *owner = tw->tw_prot->owner;
-	twsk_destructor((struct sock *)tw);
+
+	tcp_twsk_destructor((struct sock *)tw);
 	kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);
 	module_put(owner);
 }
@@ -88,86 +88,79 @@ void inet_twsk_put(struct inet_timewait_sock *tw)
 }
 EXPORT_SYMBOL_GPL(inet_twsk_put);
 
-static void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
-				   struct hlist_nulls_head *list)
-{
-	hlist_nulls_add_head_rcu(&tw->tw_node, list);
-}
-
-static void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
-				    struct hlist_head *list)
+static void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
 {
-	hlist_add_head(&tw->tw_bind_node, list);
-}
-
-static void inet_twsk_add_bind2_node(struct inet_timewait_sock *tw,
-				     struct hlist_head *list)
-{
-	hlist_add_head(&tw->tw_bind2_node, list);
+	__inet_twsk_schedule(tw, timeo, false);
 }
 
 /*
- * Enter the time wait state. This is called with locally disabled BH.
+ * Enter the time wait state.
  * Essentially we whip up a timewait bucket, copy the relevant info into it
  * from the SK, and mess with hash chains and list linkage.
+ *
+ * The caller must not access @tw anymore after this function returns.
  */
-void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
-			   struct inet_hashinfo *hashinfo)
+void inet_twsk_hashdance_schedule(struct inet_timewait_sock *tw,
+				  struct sock *sk,
+				  struct inet_hashinfo *hashinfo,
+				  int timeo)
 {
 	const struct inet_sock *inet = inet_sk(sk);
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);
 	spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 	struct inet_bind_hashbucket *bhead, *bhead2;
 
-	/* Step 1: Put TW into bind hash. Original socket stays there too.
-	   Note, that any socket with inet->num != 0 MUST be bound in
-	   binding cache, even if it is closed.
+	/* Put TW into bind hash. Original socket stays there too.
+	 * Note, that any socket with inet->num != 0 MUST be bound in
+	 * binding cache, even if it is closed.
 	 */
 	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
 			hashinfo->bhash_size)];
 	bhead2 = inet_bhashfn_portaddr(hashinfo, sk, twsk_net(tw), inet->inet_num);
 
+	local_bh_disable();
 	spin_lock(&bhead->lock);
 	spin_lock(&bhead2->lock);
 
 	tw->tw_tb = icsk->icsk_bind_hash;
 	WARN_ON(!icsk->icsk_bind_hash);
-	inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
 
 	tw->tw_tb2 = icsk->icsk_bind2_hash;
 	WARN_ON(!icsk->icsk_bind2_hash);
-	inet_twsk_add_bind2_node(tw, &tw->tw_tb2->deathrow);
+	sk_add_bind_node((struct sock *)tw, &tw->tw_tb2->owners);
 
 	spin_unlock(&bhead2->lock);
 	spin_unlock(&bhead->lock);
 
 	spin_lock(lock);
 
-	inet_twsk_add_node_rcu(tw, &ehead->chain);
-
-	/* Step 3: Remove SK from hash chain */
-	if (__sk_nulls_del_node_init_rcu(sk))
-		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-
-	spin_unlock(lock);
-
 	/* tw_refcnt is set to 3 because we have :
 	 * - one reference for bhash chain.
 	 * - one reference for ehash chain.
 	 * - one reference for timer.
-	 * We can use atomic_set() because prior spin_lock()/spin_unlock()
-	 * committed into memory all tw fields.
 	 * Also note that after this point, we lost our implicit reference
 	 * so we are not allowed to use tw anymore.
 	 */
 	refcount_set(&tw->tw_refcnt, 3);
+
+	/* Ensure tw_refcnt has been set before tw is published.
+	 * smp_wmb() provides the necessary memory barrier to enforce this
+	 * ordering.
+	 */
+	smp_wmb();
+
+	hlist_nulls_replace_init_rcu(&sk->sk_nulls_node, &tw->tw_node);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+
+	inet_twsk_schedule(tw, timeo);
+
+	spin_unlock(lock);
+	local_bh_enable();
 }
-EXPORT_SYMBOL_GPL(inet_twsk_hashdance);
 
 static void tw_timer_handler(struct timer_list *t)
 {
-	struct inet_timewait_sock *tw = from_timer(tw, t, tw_timer);
+	struct inet_timewait_sock *tw = timer_container_of(tw, t, tw_timer);
 
 	inet_twsk_kill(tw);
 }
@@ -204,10 +197,14 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 		tw->tw_hash	    = sk->sk_hash;
 		tw->tw_ipv6only	    = 0;
 		tw->tw_transparent  = inet_test_bit(TRANSPARENT, sk);
+		tw->tw_connect_bind = !!(sk->sk_userlocks & SOCK_CONNECT_BIND);
 		tw->tw_prot	    = sk->sk_prot_creator;
 		atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
 		twsk_net_set(tw, sock_net(sk));
-		timer_setup(&tw->tw_timer, tw_timer_handler, TIMER_PINNED);
+		timer_setup(&tw->tw_timer, tw_timer_handler, 0);
+#ifdef CONFIG_SOCK_VALIDATE_XMIT
+		tw->tw_validate_xmit_skb = NULL;
+#endif
 		/*
 		 * Because we use RCU lookups, we should not set tw_refcnt
 		 * to a non null value before everything is setup for this
@@ -216,11 +213,11 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 		refcount_set(&tw->tw_refcnt, 0);
 
 		__module_get(tw->tw_prot->owner);
+		psp_twsk_init(tw, sk);
 	}
 
 	return tw;
 }
-EXPORT_SYMBOL_GPL(inet_twsk_alloc);
 
 /* These are always called from BH context.  See callers in
  * tcp_input.c to verify this.
@@ -232,7 +229,34 @@ EXPORT_SYMBOL_GPL(inet_twsk_alloc);
  */
 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw)
 {
-	if (del_timer_sync(&tw->tw_timer))
+	struct inet_hashinfo *hashinfo = tw->tw_dr->hashinfo;
+	spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
+
+	/* inet_twsk_purge() walks over all sockets, including tw ones,
+	 * and removes them via inet_twsk_deschedule_put() after a
+	 * refcount_inc_not_zero().
+	 *
+	 * inet_twsk_hashdance_schedule() must (re)init the refcount before
+	 * arming the timer, i.e. inet_twsk_purge can obtain a reference to
+	 * a twsk that did not yet schedule the timer.
+	 *
+	 * The ehash lock synchronizes these two:
+	 * After acquiring the lock, the timer is always scheduled (else
+	 * timer_shutdown returns false), because hashdance_schedule releases
+	 * the ehash lock only after completing the timer initialization.
+	 *
+	 * Without grabbing the ehash lock, we get:
+	 * 1) cpu x sets twsk refcount to 3
+	 * 2) cpu y bumps refcount to 4
+	 * 3) cpu y calls inet_twsk_deschedule_put() and shuts timer down
+	 * 4) cpu x tries to start timer, but mod_timer is a noop post-shutdown
+	 * -> timer refcount is never decremented.
+	 */
+	spin_lock(lock);
+	/*  Makes sure hashdance_schedule() has completed */
+	spin_unlock(lock);
+
+	if (timer_shutdown_sync(&tw->tw_timer))
 		inet_twsk_kill(tw);
 	inet_twsk_put(tw);
 }
@@ -276,54 +300,52 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 		mod_timer_pending(&tw->tw_timer, jiffies + timeo);
 	}
 }
-EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
 
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
+/* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */
+void inet_twsk_purge(struct inet_hashinfo *hashinfo)
 {
-	struct inet_timewait_sock *tw;
-	struct sock *sk;
+	struct inet_ehash_bucket *head = &hashinfo->ehash[0];
+	unsigned int ehash_mask = hashinfo->ehash_mask;
 	struct hlist_nulls_node *node;
 	unsigned int slot;
+	struct sock *sk;
+
+	for (slot = 0; slot <= ehash_mask; slot++, head++) {
+		if (hlist_nulls_empty(&head->chain))
+			continue;
 
-	for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
-		struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 restart_rcu:
 		cond_resched();
 		rcu_read_lock();
 restart:
 		sk_nulls_for_each_rcu(sk, node, &head->chain) {
-			if (sk->sk_state != TCP_TIME_WAIT) {
-				/* A kernel listener socket might not hold refcnt for net,
-				 * so reqsk_timer_handler() could be fired after net is
-				 * freed.  Userspace listener and reqsk never exist here.
-				 */
-				if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV &&
-					     hashinfo->pernet)) {
-					struct request_sock *req = inet_reqsk(sk);
-
-					inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req);
-				}
+			int state = inet_sk_state_load(sk);
 
+			if ((1 << state) & ~(TCPF_TIME_WAIT |
+					     TCPF_NEW_SYN_RECV))
 				continue;
-			}
 
-			tw = inet_twsk(sk);
-			if ((tw->tw_family != family) ||
-				refcount_read(&twsk_net(tw)->ns.count))
+			if (check_net(sock_net(sk)))
 				continue;
 
-			if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
+			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 				continue;
 
-			if (unlikely((tw->tw_family != family) ||
-				     refcount_read(&twsk_net(tw)->ns.count))) {
-				inet_twsk_put(tw);
+			if (check_net(sock_net(sk))) {
+				sock_gen_put(sk);
 				goto restart;
 			}
 
 			rcu_read_unlock();
 			local_bh_disable();
-			inet_twsk_deschedule_put(tw);
+			if (state == TCP_TIME_WAIT) {
+				inet_twsk_deschedule_put(inet_twsk(sk));
+			} else {
+				struct request_sock *req = inet_reqsk(sk);
+
+				inet_csk_reqsk_queue_drop_and_put(req->rsk_listener,
+								  req);
+			}
 			local_bh_enable();
 			goto restart_rcu;
 		}
@@ -336,4 +358,3 @@ restart:
 		rcu_read_unlock();
 	}
 }
-EXPORT_SYMBOL_GPL(inet_twsk_purge);