/*      $OpenBSD: bfd.h,v 1.14 2025/07/24 00:49:22 jsg Exp $    */

/*
 * Copyright (c) 2016 Peter Hessler <phessler@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Support for Bi-directional Forwarding Detection (RFC 5880 / 5881)
 */

#ifndef _NET_BFD_H_
#define _NET_BFD_H_

/* Public Interface */

#define BFD_MODE_ASYNC                  1
#define BFD_MODE_DEMAND                 2

/* Diagnostic Code (RFC 5880 Page 8) */
#define BFD_DIAG_NONE                   0
#define BFD_DIAG_EXPIRED                1
#define BFD_DIAG_ECHO_FAILED            2
#define BFD_DIAG_NEIGHBOR_SIGDOWN       3
#define BFD_DIAG_FIB_RESET              4
#define BFD_DIAG_PATH_DOWN              5
#define BFD_DIAG_CONCAT_PATH_DOWN       6
#define BFD_DIAG_ADMIN_DOWN             7
#define BFD_DIAG_CONCAT_REVERSE_DOWN    8

/* State (RFC 5880 Page 8) */
#define BFD_STATE_ADMINDOWN             0
#define BFD_STATE_DOWN                  1
#define BFD_STATE_INIT                  2
#define BFD_STATE_UP                    3

/* Flags (RFC 5880 Page 8) */
#define BFD_FLAG_P                      0x20
#define BFD_FLAG_F                      0x10
#define BFD_FLAG_C                      0x08
#define BFD_FLAG_A                      0x04
#define BFD_FLAG_D                      0x02
#define BFD_FLAG_M                      0x01

struct sockaddr_bfd {
        uint8_t         bs_len;         /* total length */
        uint8_t         bs_family;      /* address family */
        /* above matches sockaddr_storage */

        /* Sorted for bit boundaries */
        uint16_t        bs_mode;
        uint32_t        bs_localdiscr;

        int64_t         bs_uptime;

        int64_t         bs_lastuptime;

        uint32_t        bs_mintx;
        uint32_t        bs_minrx;

        uint32_t        bs_minecho;
        uint32_t        bs_localdiag;

        uint32_t        bs_remotediscr;
        uint32_t        bs_remotediag;

        uint16_t        bs_multiplier;
        uint16_t        bs_pad0;
        unsigned int    bs_state;
        unsigned int    bs_remotestate;
        unsigned int    bs_laststate;
        unsigned int    bs_error;

        /* add padding to reach a power of two */
        uint64_t        bs_pad1;
};

struct bfd_msghdr {
        uint16_t        bm_msglen;
        uint8_t         bm_version;
        uint8_t         bm_type;
        uint16_t        bm_hdrlen;
        uint16_t        bm_index;

        uint16_t        bm_tableid;
        uint8_t         bm_priority;
        uint8_t         bm_mpls;
        int             bm_addrs;
        int             bm_flags;
        /* above matches rt_msghdr */
        uint16_t        bm_pad0;        /* for 4 byte boundary */

        struct sockaddr_bfd     bm_sa;  /* bfd msg for userland */
};

#ifdef _KERNEL
/* state machine from RFC 5880 6.8.1*/
struct bfd_neighbor {
        uint32_t        bn_lstate;              /* SessionState */
        uint32_t        bn_rstate;              /* RemoteSessionState */
        uint32_t        bn_ldiscr;              /* LocalDiscr */
        uint32_t        bn_rdiscr;              /* RemoteDiscr */
        uint32_t        bn_ldiag;               /* LocalDiag */
        uint32_t        bn_rdiag;               /* RemoteDiag */
        uint32_t        bn_mintx;               /* DesiredMinTxInterval */
        uint32_t        bn_req_minrx;           /* RequiredMinRxInterval */
        uint32_t        bn_rminrx;              /* RemoteMinRxInterval */
        uint32_t        bn_demand;              /* DemandMode */
        uint32_t        bn_rdemand;             /* RemoteDemandMode */
        uint32_t        bn_authtype;            /* AuthType */
        uint32_t        bn_rauthseq;            /* RcvAuthSeq */
        uint32_t        bn_lauthseq;            /* XmitAuthSeq */
        uint32_t        bn_authseqknown;        /* AuthSeqKnown */
        uint16_t        bn_mult;                /* DetectMult */
};

struct bfd_config {
        TAILQ_ENTRY(bfd_config)  bc_entry;
        struct socket           *bc_so;
        struct socket           *bc_upcallso;
        struct socket           *bc_soecho;
        struct socket           *bc_sosend;
        struct rtentry          *bc_rt;
        struct bfd_neighbor     *bc_neighbor;
        struct timeval          *bc_time;
        struct task              bc_bfd_task;
        struct task              bc_bfd_send_task;
        struct task              bc_upcall_task;
        struct task              bc_clear_task;
        struct timeout           bc_timo_rx;
        struct timeout           bc_timo_tx;
        time_t                   bc_lastuptime;
        unsigned int             bc_laststate;
        unsigned int             bc_state;
        unsigned int             bc_poll;
        unsigned int             bc_error;
        uint32_t                 bc_minrx;
        uint32_t                 bc_mintx;
        uint32_t                 bc_minecho;
        uint16_t                 bc_multiplier;
        uint16_t                 bc_mode;
};

struct sockaddr *bfd2sa(const struct rtentry *, struct sockaddr_bfd *);

int              bfdset(struct rtentry *);
void             bfdclear(struct rtentry *);
void             bfdinit(void);

#endif /* _KERNEL */

#endif /* _NET_BFD_H_ */