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);
48int syncache_pcblist(struct sysctl_req *);
49
50struct syncache {
51 TAILQ_ENTRY(syncache) sc_hash;
52 struct in_conninfo sc_inc; /* addresses */
53 int sc_rxttime; /* retransmit time */
54 u_int16_t sc_rxmits; /* retransmit counter */
55 u_int16_t sc_port; /* remote UDP encaps port */
56 u_int32_t sc_tsreflect; /* timestamp to reflect */
57 u_int32_t sc_tsoff; /* ts offset w/ syncookies */
58 u_int32_t sc_flowlabel; /* IPv6 flowlabel */
59 tcp_seq sc_irs; /* seq from peer */
60 tcp_seq sc_iss; /* our ISS */
61 struct mbuf *sc_ipopts; /* source route */
62 u_int16_t sc_peer_mss; /* peer's MSS */
63 u_int16_t sc_wnd; /* advertised window */
64 u_int8_t sc_ip_ttl; /* TTL / Hop Limit */
65 u_int8_t sc_ip_tos; /* TOS / Traffic Class */
66 u_int8_t sc_requested_s_scale:4,
67 sc_requested_r_scale:4;
68 u_int16_t sc_flags;
69 u_int32_t sc_challenge_ack_cnt; /* chall. ACKs sent in epoch */
70 sbintime_t sc_challenge_ack_end; /* End of chall. ack epoch */
71#if defined(TCP_OFFLOAD)
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_MASK 0x700 /* ECN codepoint mask */
93#define SCF_ECN 0x100 /* send ECN setup packet */
94#define SCF_ACE_N 0x400 /* send ACE non-ECT setup */
95#define SCF_ACE_0 0x500 /* send ACE ECT0 setup */
96#define SCF_ACE_1 0x600 /* send ACE ECT1 setup */
97#define SCF_ACE_CE 0x700 /* send ACE CE setup */
98
99struct syncache_head {
100 struct mtx sch_mtx;
101 TAILQ_HEAD(sch_head, syncache) sch_bucket;
102 struct callout sch_timer;
103 int sch_nextc;
104 u_int sch_length;
105 struct tcp_syncache *sch_sc;
106 time_t sch_last_overflow;
107};
108
109#define SYNCOOKIE_SECRET_SIZE 16
110#define SYNCOOKIE_LIFETIME 15 /* seconds */
111
112struct syncookie_secret {
113 volatile u_int oddeven;
114 uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
115 struct callout reseed;
116 u_int lifetime;
117};
118
119#define TCP_SYNCACHE_PAUSE_TIME SYNCOOKIE_LIFETIME
120#define TCP_SYNCACHE_MAX_BACKOFF 6 /* 16 minutes */
121
122struct tcp_syncache {
123 struct syncache_head *hashbase;
124 uma_zone_t zone;
125 u_int hashsize;
126 u_int hashmask;
127 u_int bucket_limit;
128 u_int cache_limit;
129 u_int rexmt_limit;
130 uint32_t hash_secret;
131#ifdef VIMAGE
132 struct vnet *vnet;
133#endif
134 struct syncookie_secret secret;
135 struct mtx pause_mtx;
136 struct callout pause_co;
137 time_t pause_until;
138 uint8_t pause_backoff;
139 volatile bool paused;
140 bool see_other;
141};
142
143/* Internal use for the syncookie functions. */
144union syncookie {
145 uint8_t cookie;
146 struct {
147 uint8_t odd_even:1,
148 sack_ok:1,
149 wscale_idx:3,
150 mss_idx:3;
151 } flags;
152};
153
154#endif /* _KERNEL */
155#endif /* !_NETINET_TCP_SYNCACHE_H_ */