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31 * @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
35 #ifndef _NETINET_TCP_SYNCACHE_H_
36 #define _NETINET_TCP_SYNCACHE_H_
39 void syncache_init(void);
41 void syncache_destroy(void);
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 *);
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;
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 */
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 */
83 * Flags for the sc_flags field.
85 #define SCF_NOOPT 0x01 /* no TCP options */
86 #define SCF_WINSCALE 0x02 /* negotiated window scaling */
87 #define SCF_TIMESTAMP 0x04 /* negotiated timestamps */
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 */
98 struct syncache_head {
100 TAILQ_HEAD(sch_head, syncache) sch_bucket;
101 struct callout sch_timer;
104 struct tcp_syncache *sch_sc;
105 time_t sch_last_overflow;
108 #define SYNCOOKIE_SECRET_SIZE 16
109 #define SYNCOOKIE_LIFETIME 15 /* seconds */
111 struct syncookie_secret {
112 volatile u_int oddeven;
113 uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
114 struct callout reseed;
118 #define TCP_SYNCACHE_PAUSE_TIME SYNCOOKIE_LIFETIME
119 #define TCP_SYNCACHE_MAX_BACKOFF 6 /* 16 minutes */
121 struct tcp_syncache {
122 struct syncache_head *hashbase;
129 uint32_t hash_secret;
131 struct syncookie_secret secret;
132 struct mtx pause_mtx;
133 struct callout pause_co;
135 uint8_t pause_backoff;
136 volatile bool paused;
139 /* Internal use for the syncookie functions. */
151 #endif /* !_NETINET_TCP_SYNCACHE_H_ */