v4.19.13 snapshot.
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
new file mode 100644
index 0000000..7877503
--- /dev/null
+++ b/include/net/inet_timewait_sock.h
@@ -0,0 +1,128 @@
+/*
+ * 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.
+ *
+ * Definitions for a generic INET TIMEWAIT sock
+ *
+ * From code originally in net/tcp.h
+ *
+ * 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.
+ */
+#ifndef _INET_TIMEWAIT_SOCK_
+#define _INET_TIMEWAIT_SOCK_
+
+#include <linux/list.h>
+#include <linux/timer.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include <net/inet_sock.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/timewait_sock.h>
+
+#include <linux/atomic.h>
+
+struct inet_bind_bucket;
+
+/*
+ * This is a TIME_WAIT sock. It works around the memory consumption
+ * problems of sockets in such a state on heavily loaded servers, but
+ * without violating the protocol specification.
+ */
+struct inet_timewait_sock {
+ /*
+ * Now struct sock also uses sock_common, so please just
+ * don't add nothing before this first member (__tw_common) --acme
+ */
+ struct sock_common __tw_common;
+#define tw_family __tw_common.skc_family
+#define tw_state __tw_common.skc_state
+#define tw_reuse __tw_common.skc_reuse
+#define tw_reuseport __tw_common.skc_reuseport
+#define tw_ipv6only __tw_common.skc_ipv6only
+#define tw_bound_dev_if __tw_common.skc_bound_dev_if
+#define tw_node __tw_common.skc_nulls_node
+#define tw_bind_node __tw_common.skc_bind_node
+#define tw_refcnt __tw_common.skc_refcnt
+#define tw_hash __tw_common.skc_hash
+#define tw_prot __tw_common.skc_prot
+#define tw_net __tw_common.skc_net
+#define tw_daddr __tw_common.skc_daddr
+#define tw_v6_daddr __tw_common.skc_v6_daddr
+#define tw_rcv_saddr __tw_common.skc_rcv_saddr
+#define tw_v6_rcv_saddr __tw_common.skc_v6_rcv_saddr
+#define tw_dport __tw_common.skc_dport
+#define tw_num __tw_common.skc_num
+#define tw_cookie __tw_common.skc_cookie
+#define tw_dr __tw_common.skc_tw_dr
+
+ __u32 tw_mark;
+ volatile unsigned char tw_substate;
+ unsigned char tw_rcv_wscale;
+
+ /* Socket demultiplex comparisons on incoming packets. */
+ /* these three are in inet_sock */
+ __be16 tw_sport;
+ /* And these are ours. */
+ unsigned int tw_kill : 1,
+ tw_transparent : 1,
+ tw_flowlabel : 20,
+ tw_pad : 2, /* 2 bits hole */
+ tw_tos : 8;
+ struct timer_list tw_timer;
+ struct inet_bind_bucket *tw_tb;
+};
+#define tw_tclass tw_tos
+
+static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
+{
+ return (struct inet_timewait_sock *)sk;
+}
+
+void inet_twsk_free(struct inet_timewait_sock *tw);
+void inet_twsk_put(struct inet_timewait_sock *tw);
+
+void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
+ struct inet_hashinfo *hashinfo);
+
+struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
+ struct inet_timewait_death_row *dr,
+ const int state);
+
+void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
+ struct inet_hashinfo *hashinfo);
+
+void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
+ bool rearm);
+
+static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
+{
+ __inet_twsk_schedule(tw, timeo, false);
+}
+
+static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
+{
+ __inet_twsk_schedule(tw, timeo, true);
+}
+
+void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
+
+void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
+
+static inline
+struct net *twsk_net(const struct inet_timewait_sock *twsk)
+{
+ return read_pnet(&twsk->tw_net);
+}
+
+static inline
+void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
+{
+ write_pnet(&twsk->tw_net, net);
+}
+#endif /* _INET_TIMEWAIT_SOCK_ */