xref: /freebsd/sys/netinet/tcp_syncache.h (revision 3cbb4cc200f8a0ad7ed08233425ea54524a21f1c)
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  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
32  * $FreeBSD$
33  */
34 
35 #ifndef _NETINET_TCP_SYNCACHE_H_
36 #define _NETINET_TCP_SYNCACHE_H_
37 #ifdef _KERNEL
38 
39 void	 syncache_init(void);
40 #ifdef VIMAGE
41 void	syncache_destroy(void);
42 #endif
43 void	 syncache_unreach(struct in_conninfo *, tcp_seq);
44 int	 syncache_expand(struct in_conninfo *, struct tcpopt *,
45 	     struct tcphdr *, struct socket **, struct mbuf *);
46 int	 syncache_add(struct in_conninfo *, struct tcpopt *,
47 	     struct tcphdr *, struct inpcb *, struct socket **, struct mbuf *,
48 	     void *, void *, uint8_t);
49 void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *, struct mbuf *);
50 void	 syncache_badack(struct in_conninfo *);
51 int	 syncache_pcblist(struct sysctl_req *);
52 
53 struct syncache {
54 	TAILQ_ENTRY(syncache)	sc_hash;
55 	struct		in_conninfo sc_inc;	/* addresses */
56 	int		sc_rxttime;		/* retransmit time */
57 	u_int16_t	sc_rxmits;		/* retransmit counter */
58 	u_int32_t	sc_tsreflect;		/* timestamp to reflect */
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;		/* TTL / Hop Limit */
67 	u_int8_t	sc_ip_tos;		/* TOS / Traffic Class */
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 	void		*sc_tfo_cookie;		/* for TCP Fast Open response */
78 	void		*sc_pspare;		/* TCP_SIGNATURE */
79 	u_int32_t	sc_spare[2];		/* UTO */
80 };
81 
82 /*
83  * Flags for the sc_flags field.
84  */
85 #define SCF_NOOPT	0x01			/* no TCP options */
86 #define SCF_WINSCALE	0x02			/* negotiated window scaling */
87 #define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
88 						/* MSS is implicit */
89 #define SCF_UNREACH	0x10			/* icmp unreachable received */
90 #define SCF_SIGNATURE	0x20			/* send MD5 digests */
91 #define SCF_SACK	0x80			/* send SACK option */
92 #define SCF_ECN		0x100			/* send ECN setup packet */
93 #define SCF_ACE_N	0x200			/* send ACE non-ECT setup */
94 #define SCF_ACE_0	0x400			/* send ACE ECT0 setup */
95 #define SCF_ACE_1	0x800			/* send ACE ECT1 setup */
96 #define SCF_ACE_CE	0x1000			/* send ACE CE setup */
97 
98 struct 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 
111 struct 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 
121 struct 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 };
138 
139 /* Internal use for the syncookie functions. */
140 union syncookie {
141 	uint8_t cookie;
142 	struct {
143 		uint8_t odd_even:1,
144 			sack_ok:1,
145 			wscale_idx:3,
146 			mss_idx:3;
147 	} flags;
148 };
149 
150 #endif /* _KERNEL */
151 #endif /* !_NETINET_TCP_SYNCACHE_H_ */
152