1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1993, 1994, 1995
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef _NETINET_TCP_SYNCACHE_H_
33#define _NETINET_TCP_SYNCACHE_H_
34#ifdef _KERNEL
35
36void	 syncache_init(void);
37#ifdef VIMAGE
38void	syncache_destroy(void);
39#endif
40void	 syncache_unreach(struct in_conninfo *, tcp_seq, uint16_t);
41int	 syncache_expand(struct in_conninfo *, struct tcpopt *,
42	     struct tcphdr *, struct socket **, struct mbuf *, uint16_t);
43struct socket *	 syncache_add(struct in_conninfo *, struct tcpopt *,
44	     struct tcphdr *, struct inpcb *, struct socket *, struct mbuf *,
45	     void *, void *, uint8_t, uint16_t);
46void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *, struct mbuf *,
47	     uint16_t);
48void	 syncache_badack(struct in_conninfo *, uint16_t);
49int	 syncache_pcblist(struct sysctl_req *);
50
51struct syncache {
52	TAILQ_ENTRY(syncache)	sc_hash;
53	struct		in_conninfo sc_inc;	/* addresses */
54	int		sc_rxttime;		/* retransmit time */
55	u_int16_t	sc_rxmits;		/* retransmit counter */
56	u_int16_t	sc_port;		/* remote UDP encaps port */
57	u_int32_t	sc_tsreflect;		/* timestamp to reflect */
58	u_int32_t	sc_tsoff;		/* ts offset w/ syncookies */
59	u_int32_t	sc_flowlabel;		/* IPv6 flowlabel */
60	tcp_seq		sc_irs;			/* seq from peer */
61	tcp_seq		sc_iss;			/* our ISS */
62	struct		mbuf *sc_ipopts;	/* source route */
63	u_int16_t	sc_peer_mss;		/* peer's MSS */
64	u_int16_t	sc_wnd;			/* advertised window */
65	u_int8_t	sc_ip_ttl;		/* TTL / Hop Limit */
66	u_int8_t	sc_ip_tos;		/* TOS / Traffic Class */
67	u_int8_t	sc_requested_s_scale:4,
68			sc_requested_r_scale:4;
69	u_int16_t	sc_flags;
70#if defined(TCP_OFFLOAD) || !defined(TCP_OFFLOAD_DISABLE)
71	struct toedev	*sc_tod;		/* entry added by this TOE */
72	void		*sc_todctx;		/* TOE driver context */
73#endif
74	struct label	*sc_label;		/* MAC label reference */
75	struct ucred	*sc_cred;		/* cred cache for jail checks */
76	void		*sc_tfo_cookie;		/* for TCP Fast Open response */
77	void		*sc_pspare;		/* TCP_SIGNATURE */
78	u_int32_t	sc_spare[2];		/* UTO */
79};
80
81/*
82 * Flags for the sc_flags field.
83 */
84#define SCF_NOOPT	0x01			/* no TCP options */
85#define SCF_WINSCALE	0x02			/* negotiated window scaling */
86#define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
87						/* MSS is implicit */
88#define SCF_UNREACH	0x10			/* icmp unreachable received */
89#define SCF_SIGNATURE	0x20			/* send MD5 digests */
90#define SCF_SACK	0x80			/* send SACK option */
91#define SCF_ECN_MASK	0x700			/* ECN codepoint mask */
92#define SCF_ECN 	0x100			/* send ECN setup packet */
93#define SCF_ACE_N	0x400			/* send ACE non-ECT setup */
94#define SCF_ACE_0	0x500			/* send ACE ECT0 setup */
95#define SCF_ACE_1	0x600			/* send ACE ECT1 setup */
96#define SCF_ACE_CE	0x700			/* send ACE CE setup */
97
98struct syncache_head {
99	struct mtx	sch_mtx;
100	TAILQ_HEAD(sch_head, syncache)	sch_bucket;
101	struct callout	sch_timer;
102	int		sch_nextc;
103	u_int		sch_length;
104	struct tcp_syncache *sch_sc;
105	time_t		sch_last_overflow;
106};
107
108#define	SYNCOOKIE_SECRET_SIZE	16
109#define	SYNCOOKIE_LIFETIME	15		/* seconds */
110
111struct syncookie_secret {
112	volatile u_int oddeven;
113	uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
114	struct callout reseed;
115	u_int lifetime;
116};
117
118#define	TCP_SYNCACHE_PAUSE_TIME		SYNCOOKIE_LIFETIME
119#define	TCP_SYNCACHE_MAX_BACKOFF	6	/* 16 minutes */
120
121struct tcp_syncache {
122	struct	syncache_head *hashbase;
123	uma_zone_t zone;
124	u_int	hashsize;
125	u_int	hashmask;
126	u_int	bucket_limit;
127	u_int	cache_limit;
128	u_int	rexmt_limit;
129	uint32_t hash_secret;
130	struct vnet *vnet;
131	struct syncookie_secret secret;
132	struct mtx pause_mtx;
133	struct callout pause_co;
134	time_t	pause_until;
135	uint8_t pause_backoff;
136	volatile bool paused;
137	bool see_other;
138};
139
140/* Internal use for the syncookie functions. */
141union syncookie {
142	uint8_t cookie;
143	struct {
144		uint8_t odd_even:1,
145			sack_ok:1,
146			wscale_idx:3,
147			mss_idx:3;
148	} flags;
149};
150
151#endif /* _KERNEL */
152#endif /* !_NETINET_TCP_SYNCACHE_H_ */
153