v4.19.13 snapshot.
diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
new file mode 100644
index 0000000..d7d2495
--- /dev/null
+++ b/include/net/secure_seq.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_SECURE_SEQ
+#define _NET_SECURE_SEQ
+
+#include <linux/types.h>
+
+u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
+u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+ __be16 dport);
+u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
+ __be16 sport, __be16 dport);
+u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr);
+u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
+ __be16 sport, __be16 dport);
+u32 secure_tcpv6_ts_off(const struct net *net,
+ const __be32 *saddr, const __be32 *daddr);
+u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
+ __be16 sport, __be16 dport);
+u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+ __be16 sport, __be16 dport);
+
+#endif /* _NET_SECURE_SEQ */