/*      $OpenBSD: sync.h,v 1.6 2025/06/04 21:16:25 dlg Exp $    */

/*
 * Copyright (c) 2008, Bob Beck <beck@openbsd.org>
 * Copyright (c) 2006, 2007 Reyk Floeter <reyk@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.
 */

#ifndef _DHCPD_SYNC
#define _DHCPD_SYNC

/*
 * dhcpd(8) synchronisation protocol.
 *
 * This protocol has been designed for realtime synchronisation between
 * multiple machines running dhcpd(8), running the same config.
 * It is a simple Type-Length-Value based protocol, it allows easy
 * extension with future subtypes and bulk transfers by sending multiple
 * entries at once. The unencrypted messages will be authenticated using
 * HMAC-SHA1.
 *
 */

#define DHCP_SYNC_VERSION       1
#define DHCP_SYNC_MCASTADDR     "224.0.1.240"   /* XXX choose valid address */
#define DHCP_SYNC_MCASTTTL      IP_DEFAULT_MULTICAST_TTL
#define DHCP_SYNC_HMAC_LEN      20      /* SHA1 */
#define DHCP_SYNC_MAXSIZE       1408
#define DHCP_SYNC_KEY           "/var/db/dhcpd.key"

#define DHCP_ALIGNBYTES         (15)
#define DHCP_ALIGN(p)           (((u_int)(p) + DHCP_ALIGNBYTES) &~ DHCP_ALIGNBYTES)

struct dhcp_synchdr {
        u_int8_t        sh_version;
        u_int8_t        sh_af;
        u_int16_t       sh_length;
        u_int32_t       sh_counter;
        u_int8_t        sh_hmac[DHCP_SYNC_HMAC_LEN];
        u_int8_t        sh_pad[4];
} __packed;

struct dhcp_synctlv_hdr {
        u_int16_t       st_type;
        u_int16_t       st_length;
} __packed;

struct dhcp_synctlv_lease {
        u_int16_t       lv_type;
        u_int16_t       lv_length;
        u_int32_t       lv_starts, lv_ends, lv_timestamp;
        struct iaddr    lv_ip_addr;
        struct hardware lv_hardware_addr;
} __packed;

#define DHCP_SYNC_END           0x0000
#define DHCP_SYNC_LEASE         0x0001

extern int       sync_init(const char *, const char *, u_short);
extern int       sync_addhost(const char *, u_short);
extern void      sync_lease(struct lease *);
#endif /* _DHCPD_SYNC */