1/*-
2 * Copyright (c) 1982, 1986, 1993, 1994, 1995
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
30 * $FreeBSD: stable/10/sys/netinet/tcp_syncache.h 322315 2017-08-09 13:26:12Z tuexen $
31 */
32
33#ifndef _NETINET_TCP_SYNCACHE_H_
34#define _NETINET_TCP_SYNCACHE_H_
35#ifdef _KERNEL
36
37void	 syncache_init(void);
38#ifdef VIMAGE
39void	syncache_destroy(void);
40#endif
41void	 syncache_unreach(struct in_conninfo *, struct tcphdr *);
42int	 syncache_expand(struct in_conninfo *, struct tcpopt *,
43	     struct tcphdr *, struct socket **, struct mbuf *);
44int	 syncache_add(struct in_conninfo *, struct tcpopt *,
45	     struct tcphdr *, struct inpcb *, struct socket **, struct mbuf *,
46	     void *, void *);
47void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *);
48void	 syncache_badack(struct in_conninfo *);
49int	 syncache_pcbcount(void);
50int	 syncache_pcblist(struct sysctl_req *req, int max_pcbs, int *pcbs_exported);
51
52struct syncache {
53	TAILQ_ENTRY(syncache)	sc_hash;
54	struct		in_conninfo sc_inc;	/* addresses */
55	int		sc_rxttime;		/* retransmit time */
56	u_int16_t	sc_rxmits;		/* retransmit counter */
57	u_int32_t	sc_tsreflect;		/* timestamp to reflect */
58	u_int32_t	sc_ts;			/* our timestamp to send */
59	u_int32_t	sc_tsoff;		/* ts offset w/ syncookies */
60	u_int32_t	sc_flowlabel;		/* IPv6 flowlabel */
61	tcp_seq		sc_irs;			/* seq from peer */
62	tcp_seq		sc_iss;			/* our ISS */
63	struct		mbuf *sc_ipopts;	/* source route */
64	u_int16_t	sc_peer_mss;		/* peer's MSS */
65	u_int16_t	sc_wnd;			/* advertised window */
66	u_int8_t	sc_ip_ttl;		/* IPv4 TTL */
67	u_int8_t	sc_ip_tos;		/* IPv4 TOS */
68	u_int8_t	sc_requested_s_scale:4,
69			sc_requested_r_scale:4;
70	u_int16_t	sc_flags;
71#if defined(TCP_OFFLOAD) || !defined(TCP_OFFLOAD_DISABLE)
72	struct toedev	*sc_tod;		/* entry added by this TOE */
73	void		*sc_todctx;		/* TOE driver context */
74#endif
75	struct label	*sc_label;		/* MAC label reference */
76	struct ucred	*sc_cred;		/* cred cache for jail checks */
77#ifdef TCP_RFC7413
78	void		*sc_tfo_cookie;		/* for TCP Fast Open response */
79#endif
80	void		*sc_pspare;		/* TCP_SIGNATURE */
81	u_int32_t	sc_spare[2];		/* UTO */
82};
83
84/*
85 * Flags for the sc_flags field.
86 */
87#define SCF_NOOPT	0x01			/* no TCP options */
88#define SCF_WINSCALE	0x02			/* negotiated window scaling */
89#define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
90						/* MSS is implicit */
91#define SCF_UNREACH	0x10			/* icmp unreachable received */
92#define SCF_SIGNATURE	0x20			/* send MD5 digests */
93#define SCF_SACK	0x80			/* send SACK option */
94#define SCF_ECN		0x100			/* send ECN setup packet */
95
96struct syncache_head {
97	struct mtx	sch_mtx;
98	TAILQ_HEAD(sch_head, syncache)	sch_bucket;
99	struct callout	sch_timer;
100	int		sch_nextc;
101	u_int		sch_length;
102	struct tcp_syncache *sch_sc;
103	time_t		sch_last_overflow;
104};
105
106#define	SYNCOOKIE_SECRET_SIZE	16
107#define	SYNCOOKIE_LIFETIME	15		/* seconds */
108
109struct syncookie_secret {
110	volatile u_int oddeven;
111	uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
112	struct callout reseed;
113	u_int lifetime;
114};
115
116struct tcp_syncache {
117	struct	syncache_head *hashbase;
118	uma_zone_t zone;
119	u_int	hashsize;
120	u_int	hashmask;
121	u_int	bucket_limit;
122	u_int	cache_limit;
123	u_int	rexmt_limit;
124	u_int	hash_secret;
125	struct vnet *vnet;
126	struct syncookie_secret secret;
127};
128
129/* Internal use for the syncookie functions. */
130union syncookie {
131	uint8_t cookie;
132	struct {
133		uint8_t odd_even:1,
134			sack_ok:1,
135			wscale_idx:3,
136			mss_idx:3;
137	} flags;
138};
139
140#endif /* _KERNEL */
141#endif /* !_NETINET_TCP_SYNCACHE_H_ */
142