tcp_syncache.h

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/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1993, 1994, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)tcp_var.h   8.4 (Berkeley) 5/24/95
 * $FreeBSD$
 */
 
#ifndef _NETINET_TCP_SYNCACHE_H_
#define _NETINET_TCP_SYNCACHE_H_
#ifdef _KERNEL
 
void     syncache_init(void);
#ifdef VIMAGE
void    syncache_destroy(void);
#endif
void     syncache_unreach(struct in_conninfo *, tcp_seq, uint16_t);
int      syncache_expand(struct in_conninfo *, struct tcpopt *,
             struct tcphdr *, struct socket **, struct mbuf *, uint16_t);
struct socket *  syncache_add(struct in_conninfo *, struct tcpopt *,
             struct tcphdr *, struct inpcb *, struct socket *, struct mbuf *,
             void *, void *, uint8_t, uint16_t);
void     syncache_chkrst(struct in_conninfo *, struct tcphdr *, struct mbuf *,
             uint16_t);
void     syncache_badack(struct in_conninfo *, uint16_t);
int      syncache_pcblist(struct sysctl_req *);
 
struct syncache {
        TAILQ_ENTRY(syncache)   sc_hash;
        struct          in_conninfo sc_inc;     /* addresses */
        int             sc_rxttime;             /* retransmit time */
        u_int16_t       sc_rxmits;              /* retransmit counter */
        u_int16_t       sc_port;                /* remote UDP encaps port */
        u_int32_t       sc_tsreflect;           /* timestamp to reflect */
        u_int32_t       sc_tsoff;               /* ts offset w/ syncookies */
        u_int32_t       sc_flowlabel;           /* IPv6 flowlabel */
        tcp_seq         sc_irs;                 /* seq from peer */
        tcp_seq         sc_iss;                 /* our ISS */
        struct          mbuf *sc_ipopts;        /* source route */
        u_int16_t       sc_peer_mss;            /* peer's MSS */
        u_int16_t       sc_wnd;                 /* advertised window */
        u_int8_t        sc_ip_ttl;              /* TTL / Hop Limit */
        u_int8_t        sc_ip_tos;              /* TOS / Traffic Class */
        u_int8_t        sc_requested_s_scale:4,
                        sc_requested_r_scale:4;
        u_int16_t       sc_flags;
#if defined(TCP_OFFLOAD) || !defined(TCP_OFFLOAD_DISABLE)
        struct toedev   *sc_tod;                /* entry added by this TOE */
        void            *sc_todctx;             /* TOE driver context */
#endif
        struct label    *sc_label;              /* MAC label reference */
        struct ucred    *sc_cred;               /* cred cache for jail checks */
        void            *sc_tfo_cookie;         /* for TCP Fast Open response */
        void            *sc_pspare;             /* TCP_SIGNATURE */
        u_int32_t       sc_spare[2];            /* UTO */
};
 
/*
 * Flags for the sc_flags field.
 */
#define SCF_NOOPT       0x01                    /* no TCP options */
#define SCF_WINSCALE    0x02                    /* negotiated window scaling */
#define SCF_TIMESTAMP   0x04                    /* negotiated timestamps */
                                                /* MSS is implicit */
#define SCF_UNREACH     0x10                    /* icmp unreachable received */
#define SCF_SIGNATURE   0x20                    /* send MD5 digests */
#define SCF_SACK        0x80                    /* send SACK option */
#define SCF_ECN_MASK    0x700                   /* ECN codepoint mask */
#define SCF_ECN         0x100                   /* send ECN setup packet */
#define SCF_ACE_N       0x400                   /* send ACE non-ECT setup */
#define SCF_ACE_0       0x500                   /* send ACE ECT0 setup */
#define SCF_ACE_1       0x600                   /* send ACE ECT1 setup */
#define SCF_ACE_CE      0x700                   /* send ACE CE setup */
 
struct syncache_head {
        struct mtx      sch_mtx;
        TAILQ_HEAD(sch_head, syncache)  sch_bucket;
        struct callout  sch_timer;
        int             sch_nextc;
        u_int           sch_length;
        struct tcp_syncache *sch_sc;
        time_t          sch_last_overflow;
};
 
#define SYNCOOKIE_SECRET_SIZE   16
#define SYNCOOKIE_LIFETIME      15              /* seconds */
 
struct syncookie_secret {
        volatile u_int oddeven;
        uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
        struct callout reseed;
        u_int lifetime;
};
 
#define TCP_SYNCACHE_PAUSE_TIME         SYNCOOKIE_LIFETIME
#define TCP_SYNCACHE_MAX_BACKOFF        6       /* 16 minutes */
 
struct tcp_syncache {
        struct  syncache_head *hashbase;
        uma_zone_t zone;
        u_int   hashsize;
        u_int   hashmask;
        u_int   bucket_limit;
        u_int   cache_limit;
        u_int   rexmt_limit;
        uint32_t hash_secret;
        struct vnet *vnet;
        struct syncookie_secret secret;
        struct mtx pause_mtx;
        struct callout pause_co;
        time_t  pause_until;
        uint8_t pause_backoff;
        volatile bool paused;
        bool see_other;
};
 
/* Internal use for the syncookie functions. */
union syncookie {
        uint8_t cookie;
        struct {
                uint8_t odd_even:1,
                        sack_ok:1,
                        wscale_idx:3,
                        mss_idx:3;
        } flags;
};
 
#endif /* _KERNEL */
#endif /* !_NETINET_TCP_SYNCACHE_H_ */