/** @file
 * @brief IPv6 and IPv4 definitions
 *
 * Generic IPv6 and IPv4 address definitions.
 */

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#ifndef __NET_IP_H
#define __NET_IP_H

/**
 * @brief IPv4/IPv6 primitives and helpers
 * @defgroup ip_4_6 IPv4/IPv6 primitives and helpers
 * @ingroup networking
 * @{
 */

#include <string.h>
#include <zephyr/types.h>
#include <stdbool.h>
#include <misc/byteorder.h>
#include <toolchain.h>

#include <net/net_linkaddr.h>

#ifdef __cplusplus
extern "C" {
#endif

/** Protocol families */
#define PF_UNSPEC	0	/* Unspecified.  */
#define PF_INET		2	/* IP protocol family.  */
#define PF_INET6	10	/* IP version 6.  */

/** Address families.  */
#define AF_UNSPEC	PF_UNSPEC
#define AF_INET		PF_INET
#define AF_INET6	PF_INET6

/** Protocol numbers from IANA */
enum net_ip_protocol {
	IPPROTO_ICMP = 1,
	IPPROTO_TCP = 6,
	IPPROTO_UDP = 17,
	IPPROTO_ICMPV6 = 58,
};

/** Socket type */
enum net_sock_type {
	SOCK_STREAM = 1,
	SOCK_DGRAM,
};

#define ntohs(x) sys_be16_to_cpu(x)
#define ntohl(x) sys_be32_to_cpu(x)
#define htons(x) sys_cpu_to_be16(x)
#define htonl(x) sys_cpu_to_be32(x)

/** IPv6 address structure */
struct in6_addr {
	union {
		u8_t		u6_addr8[16];
		u16_t		u6_addr16[8]; /* In big endian */
		u32_t		u6_addr32[4]; /* In big endian */
	} in6_u;
#define s6_addr			in6_u.u6_addr8
#define s6_addr16		in6_u.u6_addr16
#define s6_addr32		in6_u.u6_addr32
};

/** IPv4 address */
struct in_addr {
	union {
		u8_t		u4_addr8[4];
		u16_t		u4_addr16[2]; /* In big endian */
		u32_t		u4_addr32[1]; /* In big endian */
	} in4_u;
#define s4_addr			in4_u.u4_addr8
#define s4_addr16		in4_u.u4_addr16
#define s4_addr32		in4_u.u4_addr32

#define s_addr			s4_addr32[0]
};

typedef unsigned short int sa_family_t;
typedef size_t socklen_t;

/**
 * Note that the sin_port and sin6_port are in network byte order
 * in various sockaddr* structs.
 */
struct sockaddr_in6 {
	sa_family_t		sin6_family;   /* AF_INET6               */
	u16_t			sin6_port;     /* Port number            */
	struct in6_addr		sin6_addr;     /* IPv6 address           */
	u8_t			sin6_scope_id; /* interfaces for a scope */
};

struct sockaddr_in6_ptr {
	sa_family_t		sin6_family;   /* AF_INET6               */
	u16_t			sin6_port;     /* Port number            */
	struct in6_addr		*sin6_addr;    /* IPv6 address           */
	u8_t			sin6_scope_id; /* interfaces for a scope */
};

struct sockaddr_in {
	sa_family_t		sin_family;    /* AF_INET      */
	u16_t			sin_port;      /* Port number  */
	struct in_addr		sin_addr;      /* IPv4 address */
};

struct sockaddr_in_ptr {
	sa_family_t		sin_family;    /* AF_INET      */
	u16_t			sin_port;      /* Port number  */
	struct in_addr		*sin_addr;     /* IPv4 address */
};

#if defined(CONFIG_NET_IPV6)
#define NET_SOCKADDR_MAX_SIZE (sizeof(struct sockaddr_in6))
#define NET_SOCKADDR_PTR_MAX_SIZE (sizeof(struct sockaddr_in6_ptr))
#elif defined(CONFIG_NET_IPV4)
#define NET_SOCKADDR_MAX_SIZE (sizeof(struct sockaddr_in))
#define NET_SOCKADDR_PTR_MAX_SIZE (sizeof(struct sockaddr_in_ptr))
#else
#if !defined(CONFIG_NET_RAW_MODE)
#error "Either IPv6 or IPv4 needs to be selected."
#else
#define NET_SOCKADDR_MAX_SIZE (sizeof(struct sockaddr_in6))
#define NET_SOCKADDR_PTR_MAX_SIZE (sizeof(struct sockaddr_in6_ptr))
#endif
#endif

struct sockaddr {
	sa_family_t sa_family;
	char data[NET_SOCKADDR_MAX_SIZE - sizeof(sa_family_t)];
};

struct sockaddr_ptr {
	sa_family_t family;
	char data[NET_SOCKADDR_PTR_MAX_SIZE - sizeof(sa_family_t)];
};

/* Same as sockaddr in our case */
struct sockaddr_storage {
	sa_family_t ss_family;
	char data[NET_SOCKADDR_MAX_SIZE - sizeof(sa_family_t)];
};

struct net_addr {
	sa_family_t family;
	union {
#if defined(CONFIG_NET_IPV6)
		struct in6_addr in6_addr;
#endif
#if defined(CONFIG_NET_IPV4)
		struct in_addr in_addr;
#endif
	};
};

#define IN6ADDR_ANY_INIT { { { 0, 0, 0, 0, 0, 0, 0, 0, 0, \
				0, 0, 0, 0, 0, 0, 0 } } }
#define IN6ADDR_LOOPBACK_INIT { { { 0, 0, 0, 0, 0, 0, 0, \
				0, 0, 0, 0, 0, 0, 0, 0, 1 } } }

extern const struct in6_addr in6addr_any;
extern const struct in6_addr in6addr_loopback;

#define INET6_ADDRSTRLEN 46
#define NET_IPV6_ADDR_LEN sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx")
#define NET_IPV4_ADDR_LEN sizeof("xxx.xxx.xxx.xxx")

#define INADDR_ANY 0
#define INADDR_ANY_INIT { { { INADDR_ANY } } }

#define NET_IPV6_MTU 1280
#define NET_IPV4_MTU  576

/** IPv6 extension headers types */
#define NET_IPV6_NEXTHDR_HBHO        0
#define NET_IPV6_NEXTHDR_DESTO       60
#define NET_IPV6_NEXTHDR_ROUTING     43
#define NET_IPV6_NEXTHDR_FRAG        44
#define NET_IPV6_NEXTHDR_NONE        59

/** IPv6/IPv4 network connection tuple */
struct net_tuple {
	/** IPv6/IPv4 remote address */
	struct net_addr *remote_addr;
	/** IPv6/IPv4 local address */
	struct net_addr *local_addr;
	/** UDP/TCP remote port */
	u16_t remote_port;
	/** UDP/TCP local port */
	u16_t local_port;
	/** IP protocol */
	enum net_ip_protocol ip_proto;
};

/** How the network address is assigned to network interface */
enum net_addr_type {
	NET_ADDR_ANY = 0,
	NET_ADDR_AUTOCONF,
	NET_ADDR_DHCP,
	NET_ADDR_MANUAL,
};

#if NET_LOG_ENABLED > 0
static inline char *net_addr_type2str(enum net_addr_type type)
{
	switch (type) {
	case NET_ADDR_AUTOCONF:
		return "AUTO";
	case NET_ADDR_DHCP:
		return "DHCP";
	case NET_ADDR_MANUAL:
		return "MANUAL";
	case NET_ADDR_ANY:
	default:
		break;
	}

	return "<unknown>";
}
#else /* NET_LOG_ENABLED */
static inline char *net_addr_type2str(enum net_addr_type type)
{
	ARG_UNUSED(type);

	return NULL;
}
#endif /* NET_LOG_ENABLED */

/** What is the current state of the network address */
enum net_addr_state {
	NET_ADDR_ANY_STATE = -1,
	NET_ADDR_TENTATIVE = 0,
	NET_ADDR_PREFERRED,
	NET_ADDR_DEPRECATED,
};

struct net_ipv6_hdr {
	u8_t vtc;
	u8_t tcflow;
	u16_t flow;
	u8_t len[2];
	u8_t nexthdr;
	u8_t hop_limit;
	struct in6_addr src;
	struct in6_addr dst;
} __packed;

struct net_ipv6_frag_hdr {
	u8_t nexthdr;
	u8_t reserved;
	u16_t offset;
	u32_t id;
} __packed;

struct net_ipv4_hdr {
	u8_t vhl;
	u8_t tos;
	u8_t len[2];
	u8_t id[2];
	u8_t offset[2];
	u8_t ttl;
	u8_t proto;
	u16_t chksum;
	struct in_addr src;
	struct in_addr dst;
} __packed;

struct net_icmp_hdr {
	u8_t type;
	u8_t code;
	u16_t chksum;
} __packed;

struct net_udp_hdr {
	u16_t src_port;
	u16_t dst_port;
	u16_t len;
	u16_t chksum;
} __packed;

struct net_tcp_hdr {
	u16_t src_port;
	u16_t dst_port;
	u8_t seq[4];
	u8_t ack[4];
	u8_t offset;
	u8_t flags;
	u8_t wnd[2];
	u16_t chksum;
	u8_t urg[2];
	u8_t optdata[0];
} __packed;

#define NET_UDPH_LEN	8			/* Size of UDP header */
#define NET_TCPH_LEN	20			/* Size of TCP header */
#define NET_ICMPH_LEN	4			/* Size of ICMP header */

#define NET_IPV6H_LEN	   40			/* Size of IPv6 header */
#define NET_ICMPV6H_LEN	   NET_ICMPH_LEN	/* Size of ICMPv6 header */
#define NET_IPV6UDPH_LEN   (NET_UDPH_LEN + NET_IPV6H_LEN) /* IPv6 + UDP */
#define NET_IPV6TCPH_LEN   (NET_TCPH_LEN + NET_IPV6H_LEN) /* IPv6 + TCP */
#define NET_IPV6ICMPH_LEN  (NET_IPV6H_LEN + NET_ICMPH_LEN) /* ICMPv6 + IPv6 */
#define NET_IPV6_FRAGH_LEN 8

#define NET_IPV4H_LEN	   20			/* Size of IPv4 header */
#define NET_ICMPV4H_LEN	   NET_ICMPH_LEN	/* Size of ICMPv4 header */
#define NET_IPV4UDPH_LEN   (NET_UDPH_LEN + NET_IPV4H_LEN) /* IPv4 + UDP */
#define NET_IPV4TCPH_LEN   (NET_TCPH_LEN + NET_IPV4H_LEN) /* IPv4 + TCP */
#define NET_IPV4ICMPH_LEN  (NET_IPV4H_LEN + NET_ICMPH_LEN) /* ICMPv4 + IPv4 */

/**
 * @brief Check if the IPv6 address is a loopback address (::1).
 *
 * @param addr IPv6 address
 *
 * @return True if address is a loopback address, False otherwise.
 */
static inline bool net_is_ipv6_addr_loopback(struct in6_addr *addr)
{
	return UNALIGNED_GET(&addr->s6_addr32[0]) == 0 &&
		UNALIGNED_GET(&addr->s6_addr32[1]) == 0 &&
		UNALIGNED_GET(&addr->s6_addr32[2]) == 0 &&
		ntohl(UNALIGNED_GET(&addr->s6_addr32[3])) == 1;
}

/**
 * @brief Check if the IPv6 address is a multicast address.
 *
 * @param addr IPv6 address
 *
 * @return True if address is multicast address, False otherwise.
 */
static inline bool net_is_ipv6_addr_mcast(const struct in6_addr *addr)
{
	return addr->s6_addr[0] == 0xFF;
}

struct net_if;

extern struct net_if_addr *net_if_ipv6_addr_lookup(const struct in6_addr *addr,
						   struct net_if **iface);

/**
 * @brief Check if IPv6 address is found in one of the network interfaces.
 *
 * @param addr IPv6 address
 *
 * @return True if address was found, False otherwise.
 */
static inline bool net_is_my_ipv6_addr(struct in6_addr *addr)
{
	return net_if_ipv6_addr_lookup(addr, NULL) != NULL;
}

extern struct net_if_mcast_addr *net_if_ipv6_maddr_lookup(
	const struct in6_addr *addr, struct net_if **iface);

/**
 * @brief Check if IPv6 multicast address is found in one of the
 * network interfaces.
 *
 * @param maddr Multicast IPv6 address
 *
 * @return True if address was found, False otherwise.
 */
static inline bool net_is_my_ipv6_maddr(struct in6_addr *maddr)
{
	return net_if_ipv6_maddr_lookup(maddr, NULL) != NULL;
}

/**
 * @brief Check if two IPv6 addresses are same when compared after prefix mask.
 *
 * @param addr1 First IPv6 address.
 * @param addr2 Second IPv6 address.
 * @param length Prefix length (max length is 128).
 *
 * @return True if IPv6 prefixes are the same, False otherwise.
 */
static inline bool net_is_ipv6_prefix(const u8_t *addr1,
				      const u8_t *addr2,
				      u8_t length)
{
	u8_t bits = 128 - length;
	u8_t bytes = length / 8;
	u8_t remain = bits % 8;
	u8_t mask;

	if (length > 128) {
		return false;
	}

	if (memcmp(addr1, addr2, bytes)) {
		return false;
	}

	if (!remain) {
		/* No remaining bits, the prefixes are the same as first
		 * bytes are the same.
		 */
		return true;
	}

	/* Create a mask that has remaining most significant bits set */
	mask = ((0xff << (8 - remain)) ^ 0xff) << remain;

	return (addr1[bytes] & mask) == (addr2[bytes] & mask);
}

/**
 * @brief Check if the IPv4 address is a loopback address (127.0.0.0/8).
 *
 * @param addr IPv4 address
 *
 * @return True if address is a loopback address, False otherwise.
 */
static inline bool net_is_ipv4_addr_loopback(struct in_addr *addr)
{
	return addr->s4_addr[0] == 127;
}

/**
 *  @brief Check if the IPv4 address is unspecified (all bits zero)
 *
 *  @param addr IPv4 address.
 *
 *  @return True if the address is unspecified, false otherwise.
 */
static inline bool net_is_ipv4_addr_unspecified(const struct in_addr *addr)
{
	return addr->s_addr == 0;
}

/**
 * @brief Check if the IPv4 address is a multicast address.
 *
 * @param addr IPv4 address
 *
 * @return True if address is multicast address, False otherwise.
 */
static inline bool net_is_ipv4_addr_mcast(const struct in_addr *addr)
{
	return (ntohl(addr->s_addr) & 0xE0000000) == 0xE0000000;
}

extern struct net_if_addr *net_if_ipv4_addr_lookup(const struct in_addr *addr,
						   struct net_if **iface);

/**
 * @brief Check if the IPv4 address is assigned to any network interface
 * in the system.
 *
 * @param addr A valid pointer on an IPv4 address
 *
 * @return True if IPv4 address is found in one of the network interfaces,
 * False otherwise.
 */
static inline bool net_is_my_ipv4_addr(const struct in_addr *addr)
{
	return net_if_ipv4_addr_lookup(addr, NULL) != NULL;
}

/**
 *  @def net_ipaddr_copy
 *  @brief Copy an IPv4 or IPv6 address
 *
 *  @param dest Destination IP address.
 *  @param src Source IP address.
 *
 *  @return Destination address.
 */
#define net_ipaddr_copy(dest, src) \
	UNALIGNED_PUT(UNALIGNED_GET(src), dest)

/**
 *  @brief Compare two IPv4 addresses
 *
 *  @param addr1 Pointer to IPv4 address.
 *  @param addr2 Pointer to IPv4 address.
 *
 *  @return True if the addresses are the same, false otherwise.
 */
static inline bool net_ipv4_addr_cmp(const struct in_addr *addr1,
				     const struct in_addr *addr2)
{
	return UNALIGNED_GET(&addr1->s_addr) == UNALIGNED_GET(&addr2->s_addr);
}

/**
 *  @brief Compare two IPv6 addresses
 *
 *  @param addr1 Pointer to IPv6 address.
 *  @param addr2 Pointer to IPv6 address.
 *
 *  @return True if the addresses are the same, false otherwise.
 */
static inline bool net_ipv6_addr_cmp(const struct in6_addr *addr1,
				     const struct in6_addr *addr2)
{
	return !memcmp(addr1, addr2, sizeof(struct in6_addr));
}

/**
 * @brief Check if the given IPv6 address is a link local address.
 *
 * @param addr A valid pointer on an IPv6 address
 *
 * @return True if it is, false otherwise.
 */
static inline bool net_is_ipv6_ll_addr(const struct in6_addr *addr)
{
	return UNALIGNED_GET(&addr->s6_addr16[0]) == htons(0xFE80);
}

/**
 * @brief Return pointer to any (all bits zeros) IPv6 address.
 *
 * @return Any IPv6 address.
 */
const struct in6_addr *net_ipv6_unspecified_address(void);

/**
 * @brief Return pointer to any (all bits zeros) IPv4 address.
 *
 * @return Any IPv4 address.
 */
const struct in_addr *net_ipv4_unspecified_address(void);

/**
 * @brief Return pointer to broadcast (all bits ones) IPv4 address.
 *
 * @return Broadcast IPv4 address.
 */
const struct in_addr *net_ipv4_broadcast_address(void);

struct net_if;
extern bool net_if_ipv4_addr_mask_cmp(struct net_if *iface,
				      struct in_addr *addr);

/**
 * @brief Check if the given address belongs to same subnet that
 * has been configured for the interface.
 *
 * @param iface A valid pointer on an interface
 * @param addr pointer on an address
 *
 * @return True if address is in same subnet, false otherwise.
 */
static inline bool net_ipv4_addr_mask_cmp(struct net_if *iface,
					  struct in_addr *addr)
{
	return net_if_ipv4_addr_mask_cmp(iface, addr);
}

/**
 *  @brief Check if the IPv6 address is unspecified (all bits zero)
 *
 *  @param addr IPv6 address.
 *
 *  @return True if the address is unspecified, false otherwise.
 */
static inline bool net_is_ipv6_addr_unspecified(const struct in6_addr *addr)
{
	return UNALIGNED_GET(&addr->s6_addr32[0]) == 0 &&
		UNALIGNED_GET(&addr->s6_addr32[1]) == 0 &&
		UNALIGNED_GET(&addr->s6_addr32[2]) == 0 &&
		UNALIGNED_GET(&addr->s6_addr32[3]) == 0;
}

/**
 *  @brief Check if the IPv6 address is solicited node multicast address
 *  FF02:0:0:0:0:1:FFXX:XXXX defined in RFC 3513
 *
 *  @param addr IPv6 address.
 *
 *  @return True if the address is solicited node address, false otherwise.
 */
static inline bool net_is_ipv6_addr_solicited_node(const struct in6_addr *addr)
{
	return UNALIGNED_GET(&addr->s6_addr32[0]) == htonl(0xff020000) &&
		UNALIGNED_GET(&addr->s6_addr32[1]) == 0x00000000 &&
		UNALIGNED_GET(&addr->s6_addr32[2]) == htonl(0x00000001) &&
		((UNALIGNED_GET(&addr->s6_addr32[3]) & htonl(0xff000000)) ==
		 htonl(0xff000000));
}

/**
 * @brief Check if the IPv6 address is a global multicast address (FFxE::/16).
 *
 * @param addr IPv6 address.
 *
 * @return True if the address is global multicast address, false otherwise.
*/
static inline bool net_is_ipv6_addr_mcast_global(const struct in6_addr *addr)
{
	return addr->s6_addr[0] == 0xff &&
		(addr->s6_addr[1] & 0x0e) == 0x0e;
}

/**
 *  @brief Create solicited node IPv6 multicast address
 *  FF02:0:0:0:0:1:FFXX:XXXX defined in RFC 3513
 *
 *  @param src IPv6 address.
 *  @param dst IPv6 address.
 */
static inline
void net_ipv6_addr_create_solicited_node(const struct in6_addr *src,
					 struct in6_addr *dst)
{
	dst->s6_addr[0]   = 0xFF;
	dst->s6_addr[1]   = 0x02;
	UNALIGNED_PUT(0, &dst->s6_addr16[1]);
	UNALIGNED_PUT(0, &dst->s6_addr16[2]);
	UNALIGNED_PUT(0, &dst->s6_addr16[3]);
	UNALIGNED_PUT(0, &dst->s6_addr16[4]);
	dst->s6_addr[10]  = 0;
	dst->s6_addr[11]  = 0x01;
	dst->s6_addr[12]  = 0xFF;
	dst->s6_addr[13]  = src->s6_addr[13];
	UNALIGNED_PUT(UNALIGNED_GET(&src->s6_addr16[7]), &dst->s6_addr16[7]);
}

/** @brief Construct an IPv6 address from eight 16-bit words.
 *
 *  @param addr IPv6 address
 *  @param addr0 16-bit word which is part of the address
 *  @param addr1 16-bit word which is part of the address
 *  @param addr2 16-bit word which is part of the address
 *  @param addr3 16-bit word which is part of the address
 *  @param addr4 16-bit word which is part of the address
 *  @param addr5 16-bit word which is part of the address
 *  @param addr6 16-bit word which is part of the address
 *  @param addr7 16-bit word which is part of the address
 */
static inline void net_ipv6_addr_create(struct in6_addr *addr,
					u16_t addr0, u16_t addr1,
					u16_t addr2, u16_t addr3,
					u16_t addr4, u16_t addr5,
					u16_t addr6, u16_t addr7)
{
	UNALIGNED_PUT(htons(addr0), &addr->s6_addr16[0]);
	UNALIGNED_PUT(htons(addr1), &addr->s6_addr16[1]);
	UNALIGNED_PUT(htons(addr2), &addr->s6_addr16[2]);
	UNALIGNED_PUT(htons(addr3), &addr->s6_addr16[3]);
	UNALIGNED_PUT(htons(addr4), &addr->s6_addr16[4]);
	UNALIGNED_PUT(htons(addr5), &addr->s6_addr16[5]);
	UNALIGNED_PUT(htons(addr6), &addr->s6_addr16[6]);
	UNALIGNED_PUT(htons(addr7), &addr->s6_addr16[7]);
}

/**
 *  @brief Create link local allnodes multicast IPv6 address
 *
 *  @param addr IPv6 address
 */
static inline void net_ipv6_addr_create_ll_allnodes_mcast(struct in6_addr *addr)
{
	net_ipv6_addr_create(addr, 0xff02, 0, 0, 0, 0, 0, 0, 0x0001);
}

/**
 *  @brief Create IPv6 address interface identifier
 *
 *  @param addr IPv6 address
 *  @param lladdr Link local address
 */
static inline void net_ipv6_addr_create_iid(struct in6_addr *addr,
					    struct net_linkaddr *lladdr)
{
	addr->s6_addr[0] = 0xfe;
	addr->s6_addr[1] = 0x80;
	UNALIGNED_PUT(0, &addr->s6_addr16[1]);
	UNALIGNED_PUT(0, &addr->s6_addr32[1]);

	switch (lladdr->len) {
	case 2:
		/* The generated IPv6 shall not toggle the
		 * Universal/Local bit. RFC 6282 ch 3.2.2
		 */
		if (lladdr->type == NET_LINK_IEEE802154) {
			UNALIGNED_PUT(0, &addr->s6_addr32[2]);
			addr->s6_addr[11] = 0xff;
			addr->s6_addr[12] = 0xfe;
			addr->s6_addr[13] = 0;
			addr->s6_addr[14] = lladdr->addr[0];
			addr->s6_addr[15] = lladdr->addr[1];
		}

		break;
	case 6:
		/* We do not toggle the Universal/Local bit
		 * in Bluetooth. See RFC 7668 ch 3.2.2
		 */
		memcpy(&addr->s6_addr[8], lladdr->addr, 3);
		addr->s6_addr[11] = 0xff;
		addr->s6_addr[12] = 0xfe;
		memcpy(&addr->s6_addr[13], lladdr->addr + 3, 3);

#if defined(CONFIG_NET_L2_BT_ZEP1656)
		/* Workaround against older Linux kernel BT IPSP code.
		 * This will be removed eventually.
		 */
		if (lladdr->type == NET_LINK_BLUETOOTH) {
			addr->s6_addr[8] ^= 0x02;
		}
#endif

		if (lladdr->type == NET_LINK_ETHERNET) {
			addr->s6_addr[8] ^= 0x02;
		}

		break;
	case 8:
		memcpy(&addr->s6_addr[8], lladdr->addr, lladdr->len);
		addr->s6_addr[8] ^= 0x02;
		break;
	}
}

/**
 *  @brief Check if given address is based on link layer address
 *
 *  @return True if it is, False otherwise
 */
static inline bool net_ipv6_addr_based_on_ll(const struct in6_addr *addr,
					     const struct net_linkaddr *lladdr)
{
	if (!addr || !lladdr) {
		return false;
	}

	switch (lladdr->len) {
	case 2:
		if (!memcmp(&addr->s6_addr[14], lladdr->addr, lladdr->len) &&
		    addr->s6_addr[8]  == 0 &&
		    addr->s6_addr[9]  == 0 &&
		    addr->s6_addr[10] == 0 &&
		    addr->s6_addr[11] == 0xff &&
		    addr->s6_addr[12] == 0xfe) {
			return true;
		}

		break;
	case 6:
		if (lladdr->type == NET_LINK_ETHERNET) {
			if (!memcmp(&addr->s6_addr[9], &lladdr->addr[1], 2) &&
			    !memcmp(&addr->s6_addr[13], &lladdr->addr[3], 3) &&
			    addr->s6_addr[11] == 0xff &&
			    addr->s6_addr[12] == 0xfe &&
			    (addr->s6_addr[8] ^ 0x02) == lladdr->addr[0]) {
				return true;
			}
		} else if (lladdr->type == NET_LINK_BLUETOOTH) {
			if (!memcmp(&addr->s6_addr[9], &lladdr->addr[1], 2) &&
			    !memcmp(&addr->s6_addr[13], &lladdr->addr[3], 3) &&
			    addr->s6_addr[11] == 0xff &&
			    addr->s6_addr[12] == 0xfe
#if defined(CONFIG_NET_L2_BT_ZEP1656)
			    /* Workaround against older Linux kernel BT IPSP
			     * code. This will be removed eventually.
			     */
			    && (addr->s6_addr[8] ^ 0x02) == lladdr->addr[0]
#endif
			    ) {
				return true;
			}
		}

		break;
	case 8:
		if (!memcmp(&addr->s6_addr[9], &lladdr->addr[1],
			    lladdr->len - 1) &&
		    (addr->s6_addr[8] ^ 0x02) == lladdr->addr[0]) {
			return true;
		}

		break;
	}

	return false;
}

/**
 * @brief Get sockaddr_in6 from sockaddr. This is a helper so that
 * the code calling this function can be made shorter.
 *
 * @param addr Socket address
 *
 * @return Pointer to IPv6 socket address
 */
static inline struct sockaddr_in6 *net_sin6(const struct sockaddr *addr)
{
	return (struct sockaddr_in6 *)addr;
}

/**
 * @brief Get sockaddr_in from sockaddr. This is a helper so that
 * the code calling this function can be made shorter.
 *
 * @param addr Socket address
 *
 * @return Pointer to IPv4 socket address
 */
static inline struct sockaddr_in *net_sin(const struct sockaddr *addr)
{
	return (struct sockaddr_in *)addr;
}

/**
 * @brief Get sockaddr_in6_ptr from sockaddr_ptr. This is a helper so that
 * the code calling this function can be made shorter.
 *
 * @param addr Socket address
 *
 * @return Pointer to IPv6 socket address
 */
static inline
struct sockaddr_in6_ptr *net_sin6_ptr(const struct sockaddr_ptr *addr)
{
	return (struct sockaddr_in6_ptr *)addr;
}

/**
 * @brief Get sockaddr_in_ptr from sockaddr_ptr. This is a helper so that
 * the code calling this function can be made shorter.
 *
 * @param addr Socket address
 *
 * @return Pointer to IPv4 socket address
 */
static inline
struct sockaddr_in_ptr *net_sin_ptr(const struct sockaddr_ptr *addr)
{
	return (struct sockaddr_in_ptr *)addr;
}

/**
 * @brief Convert a string to IP address.
 *
 * @param family IP address family (AF_INET or AF_INET6)
 * @param src IP address in a null terminated string
 * @param dst Pointer to struct in_addr if family is AF_INET or
 * pointer to struct in6_addr if family is AF_INET6
 *
 * @note This function doesn't do precise error checking,
 * do not use for untrusted strings.
 *
 * @return 0 if ok, < 0 if error
 */
int net_addr_pton(sa_family_t family, const char *src, void *dst);

/**
 * @brief Convert IP address to string form.
 *
 * @param family IP address family (AF_INET or AF_INET6)
 * @param src Pointer to struct in_addr if family is AF_INET or
 *        pointer to struct in6_addr if family is AF_INET6
 * @param dst IP address in a non-null terminated string
 * @param size Number of bytes available in the buffer
 *
 * @return dst pointer if ok, NULL if error
 */
char *net_addr_ntop(sa_family_t family, const void *src,
		    char *dst, size_t size);

/**
 * @brief Parse a string that contains either IPv4 or IPv6 address
 * and optional port, and store the information in user supplied
 * sockaddr struct.
 *
 * @details Syntax of the IP address string:
 *   192.0.2.1:80
 *   192.0.2.42
 *   [2001:db8::1]:8080
 *   [2001:db8::2]
 *   2001:db::42
 * Note that the str_len parameter is used to restrict the amount of
 * characters that are checked. If the string does not contain port
 * number, then the port number in sockaddr is not modified.
 *
 * @param str String that contains the IP address.
 * @param str_len Length of the string to be parsed.
 * @param addr Pointer to user supplied struct sockaddr.
 *
 * @return True if parsing could be done, false otherwise.
 */
bool net_ipaddr_parse(const char *str, size_t str_len,
		      struct sockaddr *addr);

/**
 * @brief Compare TCP sequence numbers.
 *
 * @details This function compares TCP sequence numbers,
 *          accounting for wraparound effects.
 *
 * @param seq1 First sequence number
 * @param seq2 Seconds sequence number
 *
 * @return < 0 if seq1 < seq2, 0 if seq1 == seq2, > 0 if seq > seq2
 */
static inline s32_t net_tcp_seq_cmp(u32_t seq1, u32_t seq2)
{
	return (s32_t)(seq1 - seq2);
}

/**
 * @brief Check that one TCP sequence number is greater.
 *
 * @details This is convenience function on top of net_tcp_seq_cmp().
 *
 * @param seq1 First sequence number
 * @param seq2 Seconds sequence number
 *
 * @return True if seq > seq2
 */
static inline bool net_tcp_seq_greater(u32_t seq1, u32_t seq2)
{
	return net_tcp_seq_cmp(seq1, seq2) > 0;
}

#ifdef __cplusplus
}
#endif

/**
 * @}
 */


#endif /* __NET_IP_H */