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: releng/12.0/sys/netinet/tcp_syncache.h 339430 2018-10-18 19:21:18Z tuexen $
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 *);
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 *req, int max_pcbs, int *pcbs_exported);
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; /* 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 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
94 struct syncache_head {
95 struct mtx sch_mtx;
96 TAILQ_HEAD(sch_head, syncache) sch_bucket;
97 struct callout sch_timer;
98 int sch_nextc;
99 u_int sch_length;
100 struct tcp_syncache *sch_sc;
101 time_t sch_last_overflow;
102 };
103
104 #define SYNCOOKIE_SECRET_SIZE 16
105 #define SYNCOOKIE_LIFETIME 15 /* seconds */
106
107 struct syncookie_secret {
108 volatile u_int oddeven;
109 uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
110 struct callout reseed;
111 u_int lifetime;
112 };
113
114 struct tcp_syncache {
115 struct syncache_head *hashbase;
116 uma_zone_t zone;
117 u_int hashsize;
118 u_int hashmask;
119 u_int bucket_limit;
120 u_int cache_limit;
121 u_int rexmt_limit;
122 uint32_t hash_secret;
123 struct vnet *vnet;
124 struct syncookie_secret secret;
125 };
126
127 /* Internal use for the syncookie functions. */
128 union syncookie {
129 uint8_t cookie;
130 struct {
131 uint8_t odd_even:1,
132 sack_ok:1,
133 wscale_idx:3,
134 mss_idx:3;
135 } flags;
136 };
137
138 #endif /* _KERNEL */
139 #endif /* !_NETINET_TCP_SYNCACHE_H_ */
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