/** @file
 @brief ICMPv6 handler

 This is not to be included by the application.
 */

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __ICMPV6_H
#define __ICMPV6_H

#include <misc/slist.h>
#include <stdint.h>

#include <net/net_ip.h>
#include <net/nbuf.h>

struct net_icmpv6_ns_hdr {
	uint32_t reserved;
	struct in6_addr tgt;
} __packed;

struct net_icmpv6_nd_opt_hdr {
	uint8_t type;
	uint8_t len;
} __packed;

struct net_icmpv6_na_hdr {
	uint8_t flags;
	uint8_t reserved[3];
	struct in6_addr tgt;
} __packed;

struct net_icmpv6_rs_hdr {
	uint32_t reserved;
} __packed;

struct net_icmpv6_ra_hdr {
	uint8_t cur_hop_limit;
	uint8_t flags;
	uint16_t router_lifetime;
	uint32_t reachable_time;
	uint32_t retrans_timer;
} __packed;

struct net_icmpv6_nd_opt_mtu {
	uint8_t type;
	uint8_t len;
	uint16_t reserved;
	uint32_t mtu;
} __packed;

struct net_icmpv6_nd_opt_prefix_info {
	uint8_t type;
	uint8_t len;
	uint8_t prefix_len;
	uint8_t flags;
	uint32_t valid_lifetime;
	uint32_t preferred_lifetime;
	uint32_t reserved;
	struct in6_addr prefix;
} __packed;

#define NET_ICMPV6_NS_BUF(buf)						\
	((struct net_icmpv6_ns_hdr *)(net_nbuf_icmp_data(buf) +		\
				      sizeof(struct net_icmp_hdr)))

#define NET_ICMPV6_ND_OPT_HDR_BUF(buf)					\
	((struct net_icmpv6_nd_opt_hdr *)(net_nbuf_icmp_data(buf) +	\
					  sizeof(struct net_icmp_hdr) +	\
					  net_nbuf_ext_opt_len(buf)))

#define NET_ICMPV6_NA_BUF(buf)						\
	((struct net_icmpv6_na_hdr *)(net_nbuf_icmp_data(buf) +		\
				      sizeof(struct net_icmp_hdr)))

#define NET_ICMPV6_RS_BUF(buf)						\
	((struct net_icmpv6_rs_hdr *)(net_nbuf_icmp_data(buf) +		\
				      sizeof(struct net_icmp_hdr)))

#define NET_ICMPV6_RA_BUF(buf)						\
	((struct net_icmpv6_ra_hdr *)(net_nbuf_icmp_data(buf) +		\
				      sizeof(struct net_icmp_hdr)))

#define NET_ICMPV6_ND_O_FLAG(flag) ((flag) & 0x40)
#define NET_ICMPV6_ND_M_FLAG(flag) ((flag) & 0x80)

#define NET_ICMPV6_ND_OPT_SLLAO       1
#define NET_ICMPV6_ND_OPT_TLLAO       2
#define NET_ICMPV6_ND_OPT_PREFIX_INFO 3
#define NET_ICMPV6_ND_OPT_MTU         5
#define NET_ICMPV6_ND_OPT_RDNSS       25
#define NET_ICMPV6_ND_OPT_DNSSL       31

#define NET_ICMPV6_OPT_TYPE_OFFSET   0
#define NET_ICMPV6_OPT_LEN_OFFSET    1
#define NET_ICMPV6_OPT_DATA_OFFSET   2

#define NET_ICMPV6_NA_FLAG_ROUTER     0x80
#define NET_ICMPV6_NA_FLAG_SOLICITED  0x40
#define NET_ICMPV6_NA_FLAG_OVERRIDE   0x20
#define NET_ICMPV6_RA_FLAG_ONLINK     0x80
#define NET_ICMPV6_RA_FLAG_AUTONOMOUS 0x40

#define NET_ICMPV6_DST_UNREACH    1	/* Destination unreachable */
#define NET_ICMPV6_ECHO_REQUEST 128
#define NET_ICMPV6_ECHO_REPLY   129
#define NET_ICMPV6_RS           133	/* Router Solicitation */
#define NET_ICMPV6_RA           134	/* Router Advertisement */
#define NET_ICMPV6_NS           135	/* Neighbor Solicitation */
#define NET_ICMPV6_NA           136	/* Neighbor Advertisement */

/* Codes for ICMPv6 Destination Unreachable message */
#define NET_ICMPV6_DST_UNREACH_NO_ROUTE  0 /* No route to destination */
#define NET_ICMPV6_DST_UNREACH_ADMIN     1 /* Admin prohibited communication */
#define NET_ICMPV6_DST_UNREACH_SCOPE     2 /* Beoynd scope of source address */
#define NET_ICMPV6_DST_UNREACH_NO_ADDR   3 /* Address unrechable */
#define NET_ICMPV6_DST_UNREACH_NO_PORT   4 /* Port unreachable */
#define NET_ICMPV6_DST_UNREACH_SRC_ADDR  5 /* Source address failed */
#define NET_ICMPV6_DST_UNREACH_REJ_ROUTE 6 /* Reject route to destination */

/* ICMPv6 header has 4 unused bytes that must be zero, RFC 4443 ch 3.1 */
#define NET_ICMPV6_UNUSED_LEN 4

typedef enum net_verdict (*icmpv6_callback_handler_t)(struct net_buf *buf);

struct net_icmpv6_handler {
	sys_snode_t node;
	uint8_t type;
	uint8_t code;
	icmpv6_callback_handler_t handler;
};

/**
 * @brief Send ICMPv6 error message.
 * @param buf Network buffer that this error is related to.
 * @param type Type of the error message.
 * @param code Code of the type of the error message.
 * @return Return 0 if the sending succeed, <0 otherwise.
 */
int net_icmpv6_send_error(struct net_buf *buf, uint8_t type, uint8_t code);

void net_icmpv6_register_handler(struct net_icmpv6_handler *handler);
enum net_verdict net_icmpv6_input(struct net_buf *buf, uint16_t len,
				  uint8_t type, uint8_t code);
#if defined(CONFIG_NET_IPV6)
void net_icmpv6_init(void);
#else
#define net_icmpv6_init(...)
#endif

#endif /* __ICMPV6_H */