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/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1993, 1994, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
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 *    documentation and/or other materials provided with the distribution.
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 *    may be used to endorse or promote products derived from this software
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 */

#ifndef _NETINET_TCP_SYNCOOKIE_H_
#define _NETINET_TCP_SYNCOOKIE_H_

#include <netinet/tcp_var.h>
#include <sys/types.h>

#ifdef KERNEL_PRIVATE

void tcp_syncookie_init(void);
void tcp_syncookie_syn(struct tcp_inp *tpi, struct sockaddr *local, struct sockaddr *remote);
bool tcp_syncookie_ack(struct tcp_inp *tpi, struct socket **so2, int* dropsocket);

/*
 * Flags for the Accurate ECN setup
 */
#define SC_ECN_SETUP            0x01  /* send classic ECN setup */
#define SC_ACE_SETUP_NOT_ECT    0x02  /* send ACE not-ECT setup */
#define SC_ACE_SETUP_ECT1       0x04  /* send ACE ECT1 setup */
#define SC_ACE_SETUP_ECT0       0x08  /* send ACE ECT0 setup */
#define SC_ACE_SETUP_CE         0x10  /* send ACE CE setup */


#define SYNCOOKIE_SECRET_SIZE   16
#define SYNCOOKIE_LIFETIME      15              /* seconds */

struct syncookie_secret {
	volatile u_int oddeven;
	uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
	uint32_t last_updated;
};

typedef union {
	uint8_t cookie;
	struct {
		uint8_t odd_even:1,
		    sack_ok:1,
		    ecn_ok:1,              /* Only needed for classic ECN */
		    wscale_idx:3,
		    mss_idx:2;
	} flags;
} syncookie;
#endif /* KERNEL_PRIVATE */

#endif /* _NETINET_TCP_SYNCOOKIE_H_ */