/**
 *   Copyright (C) 2012 Steven Barth <steven@midlink.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2
 *   as published by the Free Software Foundation.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License version 2 for more details.
 *
 */
#pragma once

#include <libubox/ustream.h>
#include "odhcpd.h"

#define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
		0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}

#define ALL_DHCPV6_SERVERS {{{0xff, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
		0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x03}}}

#define DHCPV6_CLIENT_PORT 546
#define DHCPV6_SERVER_PORT 547

#define DHCPV6_MSG_SOLICIT 1
#define DHCPV6_MSG_ADVERTISE 2
#define DHCPV6_MSG_REQUEST 3
#define DHCPV6_MSG_CONFIRM 4
#define DHCPV6_MSG_RENEW 5
#define DHCPV6_MSG_REBIND 6
#define DHCPV6_MSG_REPLY 7
#define DHCPV6_MSG_RELEASE 8
#define DHCPV6_MSG_DECLINE 9
#define DHCPV6_MSG_RECONFIGURE 10
#define DHCPV6_MSG_INFORMATION_REQUEST 11
#define DHCPV6_MSG_RELAY_FORW 12
#define DHCPV6_MSG_RELAY_REPL 13

#define DHCPV6_OPT_CLIENTID 1
#define DHCPV6_OPT_SERVERID 2
#define DHCPV6_OPT_IA_NA 3
#define DHCPV6_OPT_IA_ADDR 5
#define DHCPV6_OPT_ORO 6
#define DHCPV6_OPT_STATUS 13
#define DHCPV6_OPT_RELAY_MSG 9
#define DHCPV6_OPT_AUTH 11
#define DHCPV6_OPT_USER_CLASS 15
#define DHCPV6_OPT_INTERFACE_ID 18
#define DHCPV6_OPT_RECONF_MSG 19
#define DHCPV6_OPT_RECONF_ACCEPT 20
#define DHCPV6_OPT_DNS_SERVERS 23
#define DHCPV6_OPT_DNS_DOMAIN 24
#define DHCPV6_OPT_IA_PD 25
#define DHCPV6_OPT_IA_PREFIX 26
#define DHCPV6_OPT_INFO_REFRESH 32
#define DHCPV6_OPT_FQDN 39
#define DHCPV6_OPT_SOL_MAX_RT 82
#define DHCPV6_OPT_INF_MAX_RT 83

#define DHCPV6_DUID_VENDOR 2

#define DHCPV6_STATUS_OK 0
#define DHCPV6_STATUS_NOADDRSAVAIL 2
#define DHCPV6_STATUS_NOBINDING 3
#define DHCPV6_STATUS_NOTONLINK 4
#define DHCPV6_STATUS_USEMULTICAST 5
#define DHCPV6_STATUS_NOPREFIXAVAIL 6

// I just remembered I have an old one lying around...
#define DHCPV6_ENT_NO  30462
#define DHCPV6_ENT_TYPE 1


#define DHCPV6_HOP_COUNT_LIMIT 32

struct dhcpv6_client_header {
	uint8_t msg_type;
	uint8_t transaction_id[3];
} __attribute__((packed));

struct dhcpv6_relay_header {
	uint8_t msg_type;
	uint8_t hop_count;
	struct in6_addr link_address;
	struct in6_addr peer_address;
	uint8_t options[];
} __attribute__((packed));

struct dhcpv6_relay_forward_envelope {
	uint8_t msg_type;
	uint8_t hop_count;
	struct in6_addr link_address;
	struct in6_addr peer_address;
	uint16_t interface_id_type;
	uint16_t interface_id_len;
	uint32_t interface_id_data;
	uint16_t relay_message_type;
	uint16_t relay_message_len;
} __attribute__((packed));

struct dhcpv6_auth_reconfigure {
	uint16_t type;
	uint16_t len;
	uint8_t protocol;
	uint8_t algorithm;
	uint8_t rdm;
	uint32_t replay[2];
	uint8_t reconf_type;
	uint8_t key[16];
} _packed;

struct dhcpv6_ia_hdr {
	uint16_t type;
	uint16_t len;
	uint32_t iaid;
	uint32_t t1;
	uint32_t t2;
} _packed;

struct dhcpv6_ia_prefix {
	uint16_t type;
	uint16_t len;
	uint32_t preferred;
	uint32_t valid;
	uint8_t prefix;
	struct in6_addr addr;
} _packed;

struct dhcpv6_ia_addr {
	uint16_t type;
	uint16_t len;
	struct in6_addr addr;
	uint32_t preferred;
	uint32_t valid;
} _packed;

struct dhcpv6_assignment {
	struct list_head head;
	struct sockaddr_in6 peer;
	time_t valid_until;
	time_t reconf_sent;
	int reconf_cnt;
	char *hostname;
	uint8_t key[16];
	uint32_t assigned;
	uint32_t iaid;
	uint8_t mac[6];
	uint8_t length; // length == 128 -> IA_NA, length <= 64 -> IA_PD
	bool accept_reconf;

	struct odhcpd_ipaddr *managed;
	ssize_t managed_size;
	struct ustream_fd managed_sock;

	uint32_t leasetime;
	unsigned int flags;

	uint8_t clid_len;
	uint8_t clid_data[];
};

struct dhcpv6_cer_id {
	uint16_t type;
	uint16_t len;
	uint16_t reserved;
	uint16_t auth_type;
	uint8_t auth[16];
	struct in6_addr addr;
};

typedef void (*dhcpv6_binding_cb_handler_t)(struct in6_addr *addr, int prefix,
						uint32_t pref, uint32_t valid,
						void *arg);

#define dhcpv6_for_each_option(start, end, otype, olen, odata)\
	for (uint8_t *_o = (uint8_t*)(start); _o + 4 <= (end) &&\
		((otype) = _o[0] << 8 | _o[1]) && ((odata) = (void*)&_o[4]) &&\
		((olen) = _o[2] << 8 | _o[3]) + (odata) <= (end); \
		_o += 4 + (_o[2] << 8 | _o[3]))

int dhcpv6_init_ia(struct interface *iface, int socket);
ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
		const struct sockaddr_in6 *addr, const void *data, const uint8_t *end);
int dhcpv6_ia_init(void);
int setup_dhcpv6_ia_interface(struct interface *iface, bool enable);
void dhcpv6_enum_ia_addrs(struct interface *iface, struct dhcpv6_assignment *c, time_t now,
				dhcpv6_binding_cb_handler_t func, void *arg);
void dhcpv6_write_statefile(void);
void dhcpv6_ia_preupdate(struct interface *iface);
void dhcpv6_ia_postupdate(struct interface *iface, time_t now);