/*      $OpenBSD: dhcp.h,v 1.1 2017/03/17 14:45:16 rzalamena Exp $      */

/*
 * Copyright (c) 2017 Rafael Zalamena <rzalamena@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 _DHCP_H_
#define _DHCP_H_

/* Maximum DHCP packet size. */
#define DHCP_MTU_MAX            1500

/*
 * Enterprise numbers can be found at:
 * http://www.iana.org/assignments/enterprise-numbers
 */
#define OPENBSD_ENTERPRISENO    30155
#define ENTERPRISENO_LEN        sizeof(uint32_t)

/*
 * DHCPv6 definitions and structures defined by the protocol
 * specification (RFC 3315).
 *
 * The relay part of DHCPv6 is specified in section 20 of RFC 3315 and
 * in the RFC 6221.
 */

/*
 * RFC 3315 Section 5.1 Multicast Addresses:
 * All_DHCP_Relay_Agents_and_Servers: FF02::1:2
 * All_DHCP_Servers: FF05::1:3
 */
#define DHCP6_ADDR_RELAYSERVER          "FF02::1:2"
#define DHCP6_ADDR_SERVER               "FF05::1:3"

/* DHCPv6 client/server ports */
#define DHCP6_CLIENT_PORT               546
#define DHCP6_CLIENT_PORT_STR           "546"
#define DHCP6_SERVER_PORT               547
#define DHCP6_SERVER_PORT_STR           "547"

/* DHCPv6 message types. */
#define DHCP6_MT_SOLICIT                1
#define DHCP6_MT_ADVERTISE              2
#define DHCP6_MT_REQUEST                3
#define DHCP6_MT_CONFIRM                4
#define DHCP6_MT_RENEW                  5
#define DHCP6_MT_REBIND                 6
#define DHCP6_MT_REPLY                  7
#define DHCP6_MT_RELEASE                8
#define DHCP6_MT_DECLINE                9
#define DHCP6_MT_RECONFIGURE            10
#define DHCP6_MT_INFORMATIONREQUEST     11
#define DHCP6_MT_RELAYFORW              12
#define DHCP6_MT_RELAYREPL              13

/* Maximum amount of hops limit by default. */
#define DHCP6_HOP_LIMIT                 32

/* DHCPv6 option definitions. */
#define DHCP6_OPT_CLIENTID              1
#define DHCP6_OPT_SERVERID              2
/* IANA - Identity Association for Non-temporary Address */
#define DHCP6_OPT_IANA                  3
/* IATA - Identity Association for Temporary Address */
#define DHCP6_OPT_IATA                  4
/* IA Addr - Identity Association Address */
#define DHCP6_OPT_IAADDR                5
/* ORO - Option Request Option */
#define DHCP6_OPT_ORO                   6
#define DHCP6_OPT_PREFERENCE            7
#define DHCP6_OPT_ELAPSED_TIME          8
#define DHCP6_OPT_RELAY_MSG             9
#define DHCP6_OPT_AUTH                  11
#define DHCP6_OPT_UNICAST               12
#define DHCP6_OPT_STATUSCODE            13
#define DHCP6_OPT_RAPIDCOMMIT           14
#define DHCP6_OPT_USERCLASS             15
#define DHCP6_OPT_VENDORCLASS           16
#define DHCP6_OPT_VENDOROPTS            17
#define DHCP6_OPT_INTERFACEID           18
#define DHCP6_OPT_RECONFMSG             19
#define DHCP6_OPT_RECONFACCEPT          20
/* Remote-ID is defined at RFC 4649. */
#define DHCP6_OPT_REMOTEID              37

/* DHCP option used in DHCP request/reply/relay packets. */
struct dhcp6_option {
        /* DHCP option code. */
        uint16_t                 dso_code;
        /* DHCP option payload length. */
        uint16_t                 dso_length;
        /* DHCP option data. */
        uint8_t                  dso_data[];
} __packed;

/* Client / Server message format. */
struct dhcp6_packet {
        uint8_t                  ds_msgtype;            /* message type */
        uint8_t                  ds_transactionid[3];   /* transaction id */
        struct dhcp6_option      ds_options[];
} __packed;

/* Relay Agent/Server message format. */
struct dhcp6_relay_packet {
        /* Message type: DHCP6_MT_RELAYFORW or DHCP6_MT_RELAYREPL */
        uint8_t                  dsr_msgtype;

        /* Number of relay agents that relayed this message. */
        uint8_t                  dsr_hopcount;

        /*
         * A global or site local address used by the server to Identify
         * the client link.
         */
        struct in6_addr          dsr_linkaddr;

        /*
         * The address of the client or relay agent from which the relayed
         * message was received.
         */
        struct in6_addr          dsr_peer;

        /* Must include a relay message option. */
        struct dhcp6_option      dsr_options[];
} __packed;

#endif /* _DHCP_H_ */