1 files changed, 80 insertions, 43 deletions

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 19ad9586c720..7d945a527daf 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -1,14 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/crypto.h>
-#include <linux/err.h>
-#include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/list.h>
 #include <linux/tcp.h>
 #include <linux/rcupdate.h>
-#include <linux/rculist.h>
-#include <net/inetpeer.h>
 #include <net/tcp.h>
+#include <net/busy_poll.h>
 
 void tcp_fastopen_init_key_once(struct net *net)
 {
@@ -38,7 +33,7 @@ static void tcp_fastopen_ctx_free(struct rcu_head *head)
 	struct tcp_fastopen_context *ctx =
 	    container_of(head, struct tcp_fastopen_context, rcu);
 
-	kzfree(ctx);
+	kfree_sensitive(ctx);
 }
 
 void tcp_fastopen_destroy_cipher(struct sock *sk)
@@ -55,12 +50,7 @@ void tcp_fastopen_ctx_destroy(struct net *net)
 {
 	struct tcp_fastopen_context *ctxt;
 
-	spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
-
-	ctxt = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
-				lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
-	rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, NULL);
-	spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
+	ctxt = unrcu_pointer(xchg(&net->ipv4.tcp_fastopen_ctx, NULL));
 
 	if (ctxt)
 		call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
@@ -89,18 +79,13 @@ int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
 		ctx->num = 1;
 	}
 
-	spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
 	if (sk) {
 		q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
-		octx = rcu_dereference_protected(q->ctx,
-			lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
-		rcu_assign_pointer(q->ctx, ctx);
+		octx = unrcu_pointer(xchg(&q->ctx, RCU_INITIALIZER(ctx)));
 	} else {
-		octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
-			lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
-		rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx);
+		octx = unrcu_pointer(xchg(&net->ipv4.tcp_fastopen_ctx,
+					  RCU_INITIALIZER(ctx)));
 	}
-	spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
 
 	if (octx)
 		call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
@@ -108,6 +93,29 @@ out:
 	return err;
 }
 
+int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk,
+			    u64 *key)
+{
+	struct tcp_fastopen_context *ctx;
+	int n_keys = 0, i;
+
+	rcu_read_lock();
+	if (icsk)
+		ctx = rcu_dereference(icsk->icsk_accept_queue.fastopenq.ctx);
+	else
+		ctx = rcu_dereference(net->ipv4.tcp_fastopen_ctx);
+	if (ctx) {
+		n_keys = tcp_fastopen_context_len(ctx);
+		for (i = 0; i < n_keys; i++) {
+			put_unaligned_le64(ctx->key[i].key[0], key + (i * 2));
+			put_unaligned_le64(ctx->key[i].key[1], key + (i * 2) + 1);
+		}
+	}
+	rcu_read_unlock();
+
+	return n_keys;
+}
+
 static bool __tcp_fastopen_cookie_gen_cipher(struct request_sock *req,
 					     struct sk_buff *syn,
 					     const siphash_key_t *key,
@@ -171,7 +179,7 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb)
 	if (!skb)
 		return;
 
-	skb_dst_drop(skb);
+	tcp_cleanup_skb(skb);
 	/* segs_in has been initialized to 1 in tcp_create_openreq_child().
 	 * Hence, reset segs_in to 0 before calling tcp_segs_in()
 	 * to avoid double counting.  Also, tcp_segs_in() expects
@@ -188,7 +196,7 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb)
 	TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN;
 
 	tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
-	__skb_queue_tail(&sk->sk_receive_queue, skb);
+	tcp_add_receive_queue(sk, skb);
 	tp->syn_data_acked = 1;
 
 	/* u64_stats_update_begin(&tp->syncp) not needed here,
@@ -266,13 +274,16 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk,
 	 * The request socket is not added to the ehash
 	 * because it's been added to the accept queue directly.
 	 */
-	inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS,
-				  TCP_TIMEOUT_INIT, TCP_RTO_MAX);
+	req->timeout = tcp_timeout_init(child);
+	tcp_reset_xmit_timer(child, ICSK_TIME_RETRANS,
+			     req->timeout, false);
 
 	refcount_set(&req->rsk_refcnt, 2);
 
+	sk_mark_napi_id_set(child, skb);
+
 	/* Now finish processing the fastopen child socket. */
-	tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
+	tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, skb);
 
 	tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
 
@@ -289,6 +300,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk,
 static bool tcp_fastopen_queue_check(struct sock *sk)
 {
 	struct fastopen_queue *fastopenq;
+	int max_qlen;
 
 	/* Make sure the listener has enabled fastopen, and we don't
 	 * exceed the max # of pending TFO requests allowed before trying
@@ -301,10 +313,11 @@ static bool tcp_fastopen_queue_check(struct sock *sk)
 	 * temporarily vs a server not supporting Fast Open at all.
 	 */
 	fastopenq = &inet_csk(sk)->icsk_accept_queue.fastopenq;
-	if (fastopenq->max_qlen == 0)
+	max_qlen = READ_ONCE(fastopenq->max_qlen);
+	if (max_qlen == 0)
 		return false;
 
-	if (fastopenq->qlen >= fastopenq->max_qlen) {
+	if (fastopenq->qlen >= max_qlen) {
 		struct request_sock *req1;
 		spin_lock(&fastopenq->lock);
 		req1 = fastopenq->rskq_rst_head;
@@ -326,7 +339,7 @@ static bool tcp_fastopen_no_cookie(const struct sock *sk,
 				   const struct dst_entry *dst,
 				   int flag)
 {
-	return (sock_net(sk)->ipv4.sysctl_tcp_fastopen & flag) ||
+	return (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) & flag) ||
 	       tcp_sk(sk)->fastopen_no_cookie ||
 	       (dst && dst_metric(dst, RTAX_FASTOPEN_NO_COOKIE));
 }
@@ -341,7 +354,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 			      const struct dst_entry *dst)
 {
 	bool syn_data = TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1;
-	int tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
+	int tcp_fastopen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen);
 	struct tcp_fastopen_cookie valid_foc = { .len = -1 };
 	struct sock *child;
 	int ret = 0;
@@ -356,8 +369,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 		return NULL;
 	}
 
-	if (syn_data &&
-	    tcp_fastopen_no_cookie(sk, dst, TFO_SERVER_COOKIE_NOT_REQD))
+	if (tcp_fastopen_no_cookie(sk, dst, TFO_SERVER_COOKIE_NOT_REQD))
 		goto fastopen;
 
 	if (foc->len == 0) {
@@ -392,6 +404,7 @@ fastopen:
 				}
 				NET_INC_STATS(sock_net(sk),
 					      LINUX_MIB_TCPFASTOPENPASSIVE);
+				tcp_sk(child)->syn_fastopen_child = 1;
 				return child;
 			}
 			NET_INC_STATS(sock_net(sk),
@@ -443,7 +456,7 @@ bool tcp_fastopen_defer_connect(struct sock *sk, int *err)
 
 	if (tp->fastopen_connect && !tp->fastopen_req) {
 		if (tcp_fastopen_cookie_check(sk, &mss, &cookie)) {
-			inet_sk(sk)->defer_connect = 1;
+			inet_set_bit(DEFER_CONNECT, sk);
 			return true;
 		}
 
@@ -459,7 +472,7 @@ bool tcp_fastopen_defer_connect(struct sock *sk, int *err)
 	}
 	return false;
 }
-EXPORT_SYMBOL(tcp_fastopen_defer_connect);
+EXPORT_IPV6_MOD(tcp_fastopen_defer_connect);
 
 /*
  * The following code block is to deal with middle box issues with TFO:
@@ -484,8 +497,18 @@ void tcp_fastopen_active_disable(struct sock *sk)
 {
 	struct net *net = sock_net(sk);
 
+	if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout))
+		return;
+
+	/* Paired with READ_ONCE() in tcp_fastopen_active_should_disable() */
+	WRITE_ONCE(net->ipv4.tfo_active_disable_stamp, jiffies);
+
+	/* Paired with smp_rmb() in tcp_fastopen_active_should_disable().
+	 * We want net->ipv4.tfo_active_disable_stamp to be updated first.
+	 */
+	smp_mb__before_atomic();
 	atomic_inc(&net->ipv4.tfo_active_disable_times);
-	net->ipv4.tfo_active_disable_stamp = jiffies;
+
 	NET_INC_STATS(net, LINUX_MIB_TCPFASTOPENBLACKHOLE);
 }
 
@@ -495,18 +518,29 @@ void tcp_fastopen_active_disable(struct sock *sk)
  */
 bool tcp_fastopen_active_should_disable(struct sock *sk)
 {
-	unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout;
-	int tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
+	unsigned int tfo_bh_timeout =
+		READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout);
 	unsigned long timeout;
+	int tfo_da_times;
 	int multiplier;
 
+	if (!tfo_bh_timeout)
+		return false;
+
+	tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
 	if (!tfo_da_times)
 		return false;
 
-	/* Limit timout to max: 2^6 * initial timeout */
+	/* Paired with smp_mb__before_atomic() in tcp_fastopen_active_disable() */
+	smp_rmb();
+
+	/* Limit timeout to max: 2^6 * initial timeout */
 	multiplier = 1 << min(tfo_da_times - 1, 6);
-	timeout = multiplier * tfo_bh_timeout * HZ;
-	if (time_before(jiffies, sock_net(sk)->ipv4.tfo_active_disable_stamp + timeout))
+
+	/* Paired with the WRITE_ONCE() in tcp_fastopen_active_disable(). */
+	timeout = READ_ONCE(sock_net(sk)->ipv4.tfo_active_disable_stamp) +
+		  multiplier * tfo_bh_timeout * HZ;
+	if (time_before(jiffies, timeout))
 		return true;
 
 	/* Mark check bit so we can check for successful active TFO
@@ -525,6 +559,7 @@ bool tcp_fastopen_active_should_disable(struct sock *sk)
 void tcp_fastopen_active_disable_ofo_check(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct net_device *dev;
 	struct dst_entry *dst;
 	struct sk_buff *skb;
 
@@ -541,10 +576,12 @@ void tcp_fastopen_active_disable_ofo_check(struct sock *sk)
 		}
 	} else if (tp->syn_fastopen_ch &&
 		   atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times)) {
-		dst = sk_dst_get(sk);
-		if (!(dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK)))
+		rcu_read_lock();
+		dst = __sk_dst_get(sk);
+		dev = dst ? dst_dev_rcu(dst) : NULL;
+		if (!(dev && (dev->flags & IFF_LOOPBACK)))
 			atomic_set(&sock_net(sk)->ipv4.tfo_active_disable_times, 0);
-		dst_release(dst);
+		rcu_read_unlock();
 	}
 }