1 files changed, 53 insertions, 30 deletions

diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 99e6e19b57c..7f830ff67f0 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -27,19 +27,13 @@ struct sk_buff;
 struct dst_entry;
 struct proto;
 
-/* empty to "strongly type" an otherwise void parameter.
- */
-struct request_values {
-};
-
 struct request_sock_ops {
 	int		family;
 	int		obj_size;
 	struct kmem_cache	*slab;
 	char		*slab_name;
 	int		(*rtx_syn_ack)(struct sock *sk,
-				       struct request_sock *req,
-				       struct request_values *rvp);
+				       struct request_sock *req);
 	void		(*send_ack)(struct sock *sk, struct sk_buff *skb,
 				    struct request_sock *req);
 	void		(*send_reset)(struct sock *sk,
@@ -49,13 +43,17 @@ struct request_sock_ops {
 					   struct request_sock *req);
 };
 
+int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req);
+
 /* struct request_sock - mini sock to represent a connection request
  */
 struct request_sock {
-	struct request_sock		*dl_next; /* Must be first member! */
+	struct sock_common		__req_common;
+	struct request_sock		*dl_next;
 	u16				mss;
-	u8				retrans;
-	u8				cookie_ts; /* syncookie: encode tcpopts in timestamp */
+	u8				num_retrans; /* number of retransmits */
+	u8				cookie_ts:1; /* syncookie: encode tcpopts in timestamp */
+	u8				num_timeout:7; /* number of timeouts */
 	/* The following two fields can be easily recomputed I think -AK */
 	u32				window_clamp; /* window clamp at creation time */
 	u32				rcv_wnd;	  /* rcv_wnd offered first time */
@@ -96,7 +94,8 @@ extern int sysctl_max_syn_backlog;
  */
 struct listen_sock {
 	u8			max_qlen_log;
-	/* 3 bytes hole, try to use */
+	u8			synflood_warned;
+	/* 2 bytes hole, try to use */
 	int			qlen;
 	int			qlen_young;
 	int			clock_hand;
@@ -105,6 +104,34 @@ struct listen_sock {
 	struct request_sock	*syn_table[0];
 };
 
+/*
+ * For a TCP Fast Open listener -
+ *	lock - protects the access to all the reqsk, which is co-owned by
+ *		the listener and the child socket.
+ *	qlen - pending TFO requests (still in TCP_SYN_RECV).
+ *	max_qlen - max TFO reqs allowed before TFO is disabled.
+ *
+ *	XXX (TFO) - ideally these fields can be made as part of "listen_sock"
+ *	structure above. But there is some implementation difficulty due to
+ *	listen_sock being part of request_sock_queue hence will be freed when
+ *	a listener is stopped. But TFO related fields may continue to be
+ *	accessed even after a listener is closed, until its sk_refcnt drops
+ *	to 0 implying no more outstanding TFO reqs. One solution is to keep
+ *	listen_opt around until	sk_refcnt drops to 0. But there is some other
+ *	complexity that needs to be resolved. E.g., a listener can be disabled
+ *	temporarily through shutdown()->tcp_disconnect(), and re-enabled later.
+ */
+struct fastopen_queue {
+	struct request_sock	*rskq_rst_head; /* Keep track of past TFO */
+	struct request_sock	*rskq_rst_tail; /* requests that caused RST.
+						 * This is part of the defense
+						 * against spoofing attack.
+						 */
+	spinlock_t	lock;
+	int		qlen;		/* # of pending (TCP_SYN_RECV) reqs */
+	int		max_qlen;	/* != 0 iff TFO is currently enabled */
+};
+
 /** struct request_sock_queue - queue of request_socks
  *
  * @rskq_accept_head - FIFO head of established children
@@ -128,13 +155,21 @@ struct request_sock_queue {
 	u8			rskq_defer_accept;
 	/* 3 bytes hole, try to pack */
 	struct listen_sock	*listen_opt;
+	struct fastopen_queue	*fastopenq; /* This is non-NULL iff TFO has been
+					     * enabled on this listener. Check
+					     * max_qlen != 0 in fastopen_queue
+					     * to determine if TFO is enabled
+					     * right at this moment.
+					     */
 };
 
-extern int reqsk_queue_alloc(struct request_sock_queue *queue,
-			     unsigned int nr_table_entries);
+int reqsk_queue_alloc(struct request_sock_queue *queue,
+		      unsigned int nr_table_entries);
 
-extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
-extern void reqsk_queue_destroy(struct request_sock_queue *queue);
+void __reqsk_queue_destroy(struct request_sock_queue *queue);
+void reqsk_queue_destroy(struct request_sock_queue *queue);
+void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
+			   bool reset);
 
 static inline struct request_sock *
 	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
@@ -189,25 +224,12 @@ static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue
 	return req;
 }
 
-static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
-						 struct sock *parent)
-{
-	struct request_sock *req = reqsk_queue_remove(queue);
-	struct sock *child = req->sk;
-
-	WARN_ON(child == NULL);
-
-	sk_acceptq_removed(parent);
-	__reqsk_free(req);
-	return child;
-}
-
 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
 				      struct request_sock *req)
 {
 	struct listen_sock *lopt = queue->listen_opt;
 
-	if (req->retrans == 0)
+	if (req->num_timeout == 0)
 		--lopt->qlen_young;
 
 	return --lopt->qlen;
@@ -245,7 +267,8 @@ static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
 	struct listen_sock *lopt = queue->listen_opt;
 
 	req->expires = jiffies + timeout;
-	req->retrans = 0;
+	req->num_retrans = 0;
+	req->num_timeout = 0;
 	req->sk = NULL;
 	req->dl_next = lopt->syn_table[hash];