Stack-independent helpers for IPv6 over X

This implements some common helper functions for IPv6 over X implementations based on network device types. More...

Detailed Description

This implements some common helper functions for IPv6 over X implementations based on network device types.

Attention

If you add a new network device type have at least a look at the implementation of these functions.

Files
file	l2util.h
	Link-layer helper function definitions.

Macros
#define	L2UTIL_ADDR_MAX_LEN   (8U)
	maximum expected length for addresses

Functions
int	l2util_eui64_from_addr (int dev_type, const uint8_t *addr, size_t addr_len, eui64_t *eui64)
	Converts a given hardware address to an EUI-64. More...
int	l2util_ipv6_iid_from_addr (int dev_type, const uint8_t *addr, size_t addr_len, eui64_t *iid)
	Converts a given hardware address to an IPv6 IID. More...
int	l2util_ipv6_iid_to_addr (int dev_type, const eui64_t *iid, uint8_t *addr)
	Converts an IPv6 IID to a hardware address. More...
int	l2util_ndp_addr_len_from_l2ao (int dev_type, const ndp_opt_t *opt)
	Derives the length of the link-layer address in an NDP link-layer address option from that option's length field and the given device type. More...
int	l2util_ipv6_group_to_l2_group (int dev_type, const ipv6_addr_t *ipv6_group, uint8_t *l2_group)
	Converts an IPv6 multicast address to a multicast address of the respective link layer. More...

Function Documentation

l2util_eui64_from_addr()

int l2util_eui64_from_addr	(	int	dev_type,
		const uint8_t *	addr,
		size_t	addr_len,
		eui64_t *	eui64
	)

Converts a given hardware address to an EUI-64.

Attention

When the link-layer of the interface has link-layer addresses, and NDEBUG is not defined, the node fails with an assertion instead returning -ENOTSUP.

Parameters

[in]	dev_type	The network device type of the device addr came from (either because it is the configured address of the device or from a packet that came over it).
[in]	addr	A hardware address.
[in]	addr_len	Number of bytes in addr.
[out]	eui64	The EUI-64 based on gnrc_netif_t::device_type

Returns

sizeof(eui64_t) on success.

-ENOTSUP, when dev_type does not support EUI-64 conversion.

-EINVAL, when addr_len is invalid for the dev_type.

l2util_ipv6_group_to_l2_group()

int l2util_ipv6_group_to_l2_group	(	int	dev_type,
		const ipv6_addr_t *	ipv6_group,
		uint8_t *	l2_group
	)

Converts an IPv6 multicast address to a multicast address of the respective link layer.

Precondition

There is enough allocated space in l2_group for an address for a device of type dev_type (e.g. 6 bytes for an ethernet address).

Parameters

[in]	dev_type	The network device type of the device l2_addr should be generated for.
[in]	ipv6_group	An IPv6 multicast address.
[out]	l2_group	A link layer multicast address

Returns

Length of l2_group in bytes

-ENOTSUP if link layer does not support multicast.

l2util_ipv6_iid_from_addr()

int l2util_ipv6_iid_from_addr	(	int	dev_type,
		const uint8_t *	addr,
		size_t	addr_len,
		eui64_t *	iid
	)

Converts a given hardware address to an IPv6 IID.

Attention

When the link-layer of the interface has link-layer addresses, and NDEBUG is not defined, the node fails with an assertion instead returning -ENOTSUP.

Parameters

[in]	dev_type	The network device type of the device addr came from (either because it is the configured address of the device or from a packet that came over it).
[in]	addr	A hardware address.
[in]	addr_len	Number of bytes in addr.
[out]	iid	The IID based on gnrc_netif_t::device_type

Returns

sizeof(eui64_t) on success.

-ENOTSUP, when dev_type does not support IID conversion.

-EINVAL, when addr_len is invalid for the dev_type.

l2util_ipv6_iid_to_addr()

int l2util_ipv6_iid_to_addr	(	int	dev_type,
		const eui64_t *	iid,
		uint8_t *	addr
	)

Converts an IPv6 IID to a hardware address.

Precondition

iid was based on a hardware address

The number of bytes available at addr is less or equal to L2UTIL_ADDR_MAX_LEN.

Attention

When NDEBUG is not defined, the node fails with an assertion instead of returning -ENOTSUP

Parameters

[in]	dev_type	The network device type of the device the iid came from (either because it is based on the configured address of the device or from a packet that came over it).
[in]	iid	An IID based on dev_type.
[out]	addr	The hardware address. It is assumed that iid was based on a hardware address and that the available number of bytes in addr are greater or equal to L2UTIL_ADDR_MAX_LEN.

Returns

Length of resulting addr on success.

-ENOTSUP, when dev_type does not support reverse IID conversion.

l2util_ndp_addr_len_from_l2ao()

int l2util_ndp_addr_len_from_l2ao	(	int	dev_type,
		const ndp_opt_t *	opt
	)

Derives the length of the link-layer address in an NDP link-layer address option from that option's length field and the given device type.

Note

If an RFC exists that specifies how IPv6 operates over a link-layer, this function usually implements the section "Unicast Address Mapping".

See also

RFC 4861, section 4.6.1

Attention

When NDEBUG is not defined, the node fails with an assertion instead of returning -ENOTSUP

Parameters

[in]	dev_type	The network device type of the device the opt came over in an NDP message.
[in]	opt	An NDP source/target link-layer address option.

Returns

Length of the link-layer address in opt on success

-ENOTSUP, when implementation does not know how to derive the length of the link-layer address from opt's length field based on dev_type.

-EINVAL if opt->len was an invalid value for the given dev_type.