Provides build and send functions for neighbor discovery packets. More...

Detailed Description

Provides build and send functions for neighbor discovery packets.

Files
file	ndp.h
	GNRC-specific neighbor discovery definitions.

Macros
#define	GNRC_NETTYPE_NDP (GNRC_NETTYPE_IPV6) /* usual configuration */
	gnrc_nettype: Protocol type to send NDP packets to

Functions
gnrc_pktsnip_t *	gnrc_ndp_nbr_sol_build (const ipv6_addr_t tgt, gnrc_pktsnip_t options)
	Builds a neighbor solicitation message for sending.

gnrc_pktsnip_t *	gnrc_ndp_nbr_adv_build (const ipv6_addr_t tgt, uint8_t flags, gnrc_pktsnip_t options)
	Builds a neighbor advertisement message for sending.

gnrc_pktsnip_t *	gnrc_ndp_rtr_sol_build (gnrc_pktsnip_t *options)
	Builds a router solicitation message for sending.

gnrc_pktsnip_t *	gnrc_ndp_rtr_adv_build (uint8_t cur_hl, uint8_t flags, uint16_t ltime, uint32_t reach_time, uint32_t retrans_timer, gnrc_pktsnip_t *options)
	Builds a router advertisement message for sending.

gnrc_pktsnip_t *	gnrc_ndp_opt_build (uint8_t type, size_t size, gnrc_pktsnip_t *next)
	Builds a generic NDP option.

gnrc_pktsnip_t *	gnrc_ndp_opt_sl2a_build (const uint8_t l2addr, uint8_t l2addr_len, gnrc_pktsnip_t next)
	Builds the source link-layer address option.

gnrc_pktsnip_t *	gnrc_ndp_opt_tl2a_build (const uint8_t l2addr, uint8_t l2addr_len, gnrc_pktsnip_t next)
	Builds the target link-layer address option.

gnrc_pktsnip_t *	gnrc_ndp_opt_pi_build (const ipv6_addr_t prefix, uint8_t prefix_len, uint32_t valid_ltime, uint32_t pref_ltime, uint8_t flags, gnrc_pktsnip_t next)
	Builds the prefix information option.

gnrc_pktsnip_t *	gnrc_ndp_opt_ri_build (const ipv6_addr_t prefix, uint8_t prefix_len, uint32_t route_ltime, uint8_t flags, gnrc_pktsnip_t next)
	Builds the route information option.

gnrc_pktsnip_t *	gnrc_ndp_opt_mtu_build (uint32_t mtu, gnrc_pktsnip_t *next)
	Builds the MTU option.

gnrc_pktsnip_t *	gnrc_ndp_opt_rdnss_build (uint32_t lifetime, ipv6_addr_t addrs, unsigned addrs_num, gnrc_pktsnip_t next)
	Builts the recursive DNS server option.

void	gnrc_ndp_nbr_sol_send (const ipv6_addr_t tgt, gnrc_netif_t netif, const ipv6_addr_t src, const ipv6_addr_t dst, gnrc_pktsnip_t *ext_opts)
	Send pre-compiled neighbor solicitation depending on a given network interface.

void	gnrc_ndp_nbr_adv_send (const ipv6_addr_t tgt, gnrc_netif_t netif, const ipv6_addr_t dst, bool supply_tl2a, gnrc_pktsnip_t ext_opts)
	Send pre-compiled neighbor advertisement depending on a given network interface.

void	gnrc_ndp_rtr_sol_send (gnrc_netif_t netif, const ipv6_addr_t dst)
	Send pre-compiled router solicitation depending on a given network interface.

void	gnrc_ndp_rtr_adv_send (gnrc_netif_t netif, const ipv6_addr_t src, const ipv6_addr_t dst, bool fin, gnrc_pktsnip_t ext_opts)
	Send pre-compiled router advertisement depending on a given network interface.

Macro Definition Documentation

◆ GNRC_NETTYPE_NDP

#define GNRC_NETTYPE_NDP (GNRC_NETTYPE_IPV6) /* usual configuration */

gnrc_nettype: Protocol type to send NDP packets to

Definition at line 39 of file ndp.h.

Function Documentation

◆ gnrc_ndp_nbr_adv_build()

gnrc_pktsnip_t * gnrc_ndp_nbr_adv_build	(	const ipv6_addr_t *	tgt,
		uint8_t	flags,
		gnrc_pktsnip_t *	options
	)

Builds a neighbor advertisement message for sending.

Precondition: (tgt != NULL) && !ipv6_addr_is_multicast(tgt)

See also: [RFC 4861, section 4.4](https://tools.ietf.org/html/rfc4861#section-4.4")

Parameters

[in]	tgt	For solicited advertisements, the Target Address field in the neighbor solicitaton. For and unsolicited advertisement, the address whose link-layer address has changed. Must not be NULL or a multicast address.
[in]	flags	Neighbor advertisement flags: NDP_NBR_ADV_FLAGS_R == 1 indicates, that the sender is a router, NDP_NBR_ADV_FLAGS_S == 1 indicates that the advertisement was sent in response to a neighbor solicitation, NDP_NBR_ADV_FLAGS_O == 1 indicates that the advertisement should override an existing cache entry and update the cached link-layer address.
[in]	options	Options to append to the neighbor advertisement. May be NULL for none.

Returns: The resulting ICMPv6 packet on success.; NULL, if packet buffer is full.

◆ gnrc_ndp_nbr_adv_send()

void gnrc_ndp_nbr_adv_send	(	const ipv6_addr_t *	tgt,
		gnrc_netif_t *	netif,
		const ipv6_addr_t *	dst,
		bool	supply_tl2a,
		gnrc_pktsnip_t *	ext_opts
	)

Send pre-compiled neighbor advertisement depending on a given network interface.

Precondition: (tgt != NULL) && !ipv6_addr_is_multicast(tgt); (netif != NULL) && (dst != NULL)

If netif is a forwarding interface and router advertisements are activated the NDP_NBR_ADV_FLAGS_R is set in the neighbor advertisement. If dst is IPV6_ADDR_UNSPECIFIED it will be replaced with IPV6_ADDR_ALL_NODES_LINK_LOCAL and* supply_tl2a is set to true implicitly. Otherwise, the NDP_NBR_ADV_FLAGS_S will be set. If tgt is an anycast address on netif the NDP_NBR_ADV_FLAGS_O flag will be set.

The source address of the IPv6 packet will be left unspecified, so the IPv6 module selects a fitting IPv6 address.

Parameters

[in]	tgt	Target address for the neighbor advertisement. May not be NULL and MUST NOT be multicast.
[in]	netif	Interface to send over. Must not be NULL.
[in]	dst	Destination address for neighbor advertisement. May not be NULL. Is set to IPV6_ADDR_ALL_NODES_LINK_LOCAL when equal to IPV6_ADDR_UNSPECIFIED (to allow for simple reply mechanisms to neighbor solicitations). This also implies that `supply_tl2a` must be true and the parameter will be reset accordingly. If `dst` is not IPV6_ADDR_UNSPECIFIED, the NDP_NBR_ADV_FLAGS_S flag will be set implicitly.
[in]	supply_tl2a	Add target link-layer address option to neighbor advertisement if link-layer has addresses. If `dst` is IPV6_ADDR_UNSPECIFIED, it will be set to true.
[in]	ext_opts	External options for the neighbor advertisement. Leave NULL for none. Warning: these are not tested if they are suitable for a neighbor advertisement so be sure to check that. Will be released in an error case.

◆ gnrc_ndp_nbr_sol_build()

gnrc_pktsnip_t * gnrc_ndp_nbr_sol_build	(	const ipv6_addr_t *	tgt,
		gnrc_pktsnip_t *	options
	)

Builds a neighbor solicitation message for sending.

Precondition: (tgt != NULL) && !ipv6_addr_is_multicast(tgt)

See also: RFC 4861, section 4.3

Parameters

[in]	tgt	The target address of the neighbor solicitation. Must not be NULL or a multicast address.
[in]	options	Options to append to the neighbor solicitation. May be NULL for none.

Returns: The resulting ICMPv6 packet on success.; NULL, if packet buffer is full.

◆ gnrc_ndp_nbr_sol_send()

void gnrc_ndp_nbr_sol_send	(	const ipv6_addr_t *	tgt,
		gnrc_netif_t *	netif,
		const ipv6_addr_t *	src,
		const ipv6_addr_t *	dst,
		gnrc_pktsnip_t *	ext_opts
	)

Send pre-compiled neighbor solicitation depending on a given network interface.

Precondition: (tgt != NULL) && !ipv6_addr_is_multicast(tgt); (netif != NULL) && (dst != NULL)

Parameters

[in]	tgt	The target address of the neighbor solicitation. Must not be NULL or a multicast address.
[in]	netif	Interface to send over. Must not be NULL.
[in]	src	Source address for the neighbor solicitation. Will be chosen from the interface according to `dst`, if NULL.
[in]	dst	Destination address for neighbor solicitation. Must not be NULL.
[in]	ext_opts	External options for the neighbor advertisement. Leave NULL for none. Warning: these are not tested if they are suitable for a neighbor solicitation so be sure to check that. Will be released in an error case.

◆ gnrc_ndp_opt_build()

gnrc_pktsnip_t * gnrc_ndp_opt_build	(	uint8_t	type,
		size_t	size,
		gnrc_pktsnip_t *	next
	)

Builds a generic NDP option.

Parameters

[in]	type	Type of the option.
[in]	size	Size in byte of the option (will be rounded up to the next multiple of 8).
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_opt_mtu_build()

gnrc_pktsnip_t * gnrc_ndp_opt_mtu_build	(	uint32_t	mtu,
		gnrc_pktsnip_t *	next
	)

Builds the MTU option.

See also: RFC 4861, section 4.6.4

Note: Should only be used with router advertisemnents. This is not checked however, since nodes should silently ignore it in other NDP messages.

Parameters

[in]	mtu	The recommended MTU for the link.
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_opt_pi_build()

gnrc_pktsnip_t * gnrc_ndp_opt_pi_build	(	const ipv6_addr_t *	prefix,
		uint8_t	prefix_len,
		uint32_t	valid_ltime,
		uint32_t	pref_ltime,
		uint8_t	flags,
		gnrc_pktsnip_t *	next
	)

Builds the prefix information option.

Precondition: prefix != NULL; !ipv6_addr_is_link_local(prefix) && !ipv6_addr_is_multicast(prefix); prefix_len <= 128

See also: RFC 4861, section 4.6.2

Note: Should only be used with router advertisemnents. This is not checked however, since nodes should silently ignore it in other NDP messages.

Parameters

[in]	prefix	An IPv6 address or a prefix of an IPv6 address. Must not be NULL or be a link-local or multicast address.
[in]	prefix_len	The length of `prefix` in bits. Must be between 0 and 128.
[in]	valid_ltime	Length of time in seconds that `prefix` is valid. UINT32_MAX represents infinity.
[in]	pref_ltime	Length of time in seconds that addresses using `prefix` remain preferred. UINT32_MAX represents infinity.
[in]	flags	Flags as defined in net/ndp.h. NDP_OPT_PI_FLAGS_L == 1 indicates, that `prefix` can be used for on-link determination, NDP_OPT_PI_FLAGS_A == 1 indicates, that `prefix` can be used for stateless address configuration.
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_opt_rdnss_build()

gnrc_pktsnip_t * gnrc_ndp_opt_rdnss_build	(	uint32_t	lifetime,
		ipv6_addr_t *	addrs,
		unsigned	addrs_num,
		gnrc_pktsnip_t *	next
	)

Builts the recursive DNS server option.

See also: RFC 8106, section 5.1

Precondition: addrs != NULL; addrs_num > 0

Note: Should only be used with router advertisemnents. This is not checked however, since nodes should silently ignore it in other NDP messages.

Parameters

[in]	lifetime	The lifetime of the recursive DNS servers
[in]	addrs	The addresses of the recursive DNS servers
[in]	addrs_num	The number of addresses in `addrs`
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; next, if RDNSS is not supported; NULL, if packet buffer is full

◆ gnrc_ndp_opt_ri_build()

gnrc_pktsnip_t * gnrc_ndp_opt_ri_build	(	const ipv6_addr_t *	prefix,
		uint8_t	prefix_len,
		uint32_t	route_ltime,
		uint8_t	flags,
		gnrc_pktsnip_t *	next
	)

Builds the route information option.

Precondition: prefix != NULL; !ipv6_addr_is_link_local(prefix) && !ipv6_addr_is_multicast(prefix); prefix_len <= 128

See also: RFC 4191, section 2.3

Note: Should only be used with router advertisemnents. This is not checked however, since nodes should silently ignore it in other NDP messages.

Parameters

[in]	prefix	An IPv6 address or a prefix of an IPv6 address. Must not be NULL or be a link-local or multicast address.
[in]	prefix_len	The length of `prefix` in bits. Must be between 0 and 128.
[in]	route_ltime	Length of time in seconds that `prefix` is valid. UINT32_MAX represents infinity.
[in]	flags	Flags as defined in net/ndp.h.
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_opt_sl2a_build()

gnrc_pktsnip_t * gnrc_ndp_opt_sl2a_build	(	const uint8_t *	l2addr,
		uint8_t	l2addr_len,
		gnrc_pktsnip_t *	next
	)

Builds the source link-layer address option.

Precondition: (l2addr != NULL) && (l2addr_len != 0)

See also: RFC 4861, section 4.6.1

Note: Should only be used with neighbor solicitations, router solicitations, and router advertisements. This is not checked however, since hosts should silently ignore it in other NDP messages.

Parameters

[in]	l2addr	A link-layer address of variable length. Must not be NULL.
[in]	l2addr_len	Length of `l2addr`. Must not be 0.
[in]	next	More options in the packet. NULL, if there are none.

Returns: The packet snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_opt_tl2a_build()

gnrc_pktsnip_t * gnrc_ndp_opt_tl2a_build	(	const uint8_t *	l2addr,
		uint8_t	l2addr_len,
		gnrc_pktsnip_t *	next
	)

Builds the target link-layer address option.

Precondition: (l2addr != NULL) && (l2addr_len != 0)

See also: RFC 4861, section 4.6.1

Note: Should only be used with neighbor advertisemnents and redirect packets. This is not checked however, since hosts should silently ignore it in other NDP messages.

Parameters

[in]	l2addr	A link-layer address of variable length. Must not be NULL.
[in]	l2addr_len	Length of `l2addr`. Must not be 0.
[in]	next	More options in the packet. NULL, if there are none.

Returns: The pkt snip list of options, on success; NULL, if packet buffer is full

◆ gnrc_ndp_rtr_adv_build()

gnrc_pktsnip_t * gnrc_ndp_rtr_adv_build	(	uint8_t	cur_hl,
		uint8_t	flags,
		uint16_t	ltime,
		uint32_t	reach_time,
		uint32_t	retrans_timer,
		gnrc_pktsnip_t *	options
	)

Builds a router advertisement message for sending.

See also: `[RFC 4861, section 4.2](https://tools.ietf.org/html/rfc4861#section-4.2")

Note: The source address for the packet MUST be the link-local address of the interface.

Parameters

[in]	cur_hl	Default hop limit for outgoing IP packets, 0 if unspecified by this router.
[in]	flags	Flags as defined in net/ndp.h. NDP_RTR_ADV_FLAGS_M == 1 indicates, that the addresses are managed by DHCPv6, NDP_RTR_ADV_FLAGS_O == 1 indicates that other configuration information is available via DHCPv6.
[in]	ltime	Lifetime of the default router in seconds.
[in]	reach_time	Time in milliseconds a node should assume a neighbor reachable. 0 means unspecified by the router.
[in]	retrans_timer	Time in milliseconds between retransmitted neighbor solicitations. 0 means unspecified by the router.
[in]	options	Options to append to the router advertisement. May be NULL for none.

Returns: The resulting ICMPv6 packet on success.; NULL, if packet buffer is full.

◆ gnrc_ndp_rtr_adv_send()

void gnrc_ndp_rtr_adv_send	(	gnrc_netif_t *	netif,
		const ipv6_addr_t *	src,
		const ipv6_addr_t *	dst,
		bool	fin,
		gnrc_pktsnip_t *	ext_opts
	)

Send pre-compiled router advertisement depending on a given network interface.

Precondition: (netif != NULL)

This function does not add the PIOs to the router, since they are highly dependent on external set-ups (e.g. if multihop prefix distribution is used). Provide them via ext_opts

Parameters

[in]	netif	Interface to send over. Must not be NULL.
[in]	src	Source address for the router advertisement. May be NULL to be determined by source address selection (:: if `netif` has no address).
[in]	dst	Destination address for router advertisement. ff02::1 if NULL.
[in]	fin	This is part of the router's final batch of router advertisements before ceising to be a router (set's router lifetime field to 0).
[in]	ext_opts	External options for the neighbor advertisement. Leave NULL for none. Warning: these are not tested if they are suitable for a neighbor advertisement so be sure to check that. Will be released in an error case.

◆ gnrc_ndp_rtr_sol_build()

gnrc_pktsnip_t * gnrc_ndp_rtr_sol_build ( gnrc_pktsnip_t * options )

Builds a router solicitation message for sending.

See also: `[RFC 4861, section 4.1](https://tools.ietf.org/html/rfc4861#section-4.1")

Parameters

[in] options Options to append to the router solicitation. May be NULL for none.

Returns: The resulting ICMPv6 packet on success.; NULL, if packet buffer is full.

◆ gnrc_ndp_rtr_sol_send()

void gnrc_ndp_rtr_sol_send	(	gnrc_netif_t *	netif,
		const ipv6_addr_t *	dst
	)

Send pre-compiled router solicitation depending on a given network interface.

Precondition: (netif != NULL)

Parameters

[in]	netif	Interface to send over. Must not be NULL.
[in]	dst	Destination for the router solicitation. ff02::2 if NULL.

Detailed Description

Files

Macros

Functions

Macro Definition Documentation

◆ GNRC_NETTYPE_NDP

Function Documentation

◆ gnrc_ndp_nbr_adv_build()

◆ gnrc_ndp_nbr_adv_send()

◆ gnrc_ndp_nbr_sol_build()

◆ gnrc_ndp_nbr_sol_send()

◆ gnrc_ndp_opt_build()

◆ gnrc_ndp_opt_mtu_build()

◆ gnrc_ndp_opt_pi_build()

◆ gnrc_ndp_opt_rdnss_build()

◆ gnrc_ndp_opt_ri_build()

◆ gnrc_ndp_opt_sl2a_build()

◆ gnrc_ndp_opt_tl2a_build()

◆ gnrc_ndp_rtr_adv_build()

◆ gnrc_ndp_rtr_adv_send()

◆ gnrc_ndp_rtr_sol_build()

◆ gnrc_ndp_rtr_sol_send()