6LoWPAN over BLE (RFC7668)

Functions
void	ble_addr_to_eui64 (uint8_t *dst, const uint8_t *src, int public_addr)
void	eui64_to_ble_addr (uint8_t *dst, const uint8_t *src)
err_t	rfc7668_set_context (u8_t idx, const ip6_addr_t *context)
err_t	rfc7668_output (struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
err_t	rfc7668_input (struct pbuf *p, struct netif *netif)
err_t	rfc7668_if_init (struct netif *netif)

Detailed Description

This file implements a RFC7668 implementation for 6LoWPAN over Bluetooth Low Energy. The specification is very similar to 6LoWPAN, so most of the code is re-used. Compared to 6LoWPAN, much functionality is already implemented in lower BLE layers (fragmenting, session management,...).

Usage:

• add this netif
  • don't add IPv4 addresses (no IPv4 support in RFC7668), pass 'NULL','NULL','NULL'
  • use the BLE to EUI64 conversation util to create an IPv6 link-local address from the BLE MAC (ble_addr_to_eui64)
  • input function: rfc7668_input
• set the link output function, which transmits output data to an established L2CAP channel
• If data arrives (HCI event "L2CAP_DATA_PACKET"):
  • allocate a PBUF_RAW buffer
  • let the pbuf struct point to the incoming data or copy it to the buffer
  • call netif->input

Function Documentation

ble_addr_to_eui64()

void ble_addr_to_eui64	(	uint8_t *	dst,
		const uint8_t *	src,
		int	public_addr
	)

convert BT address to EUI64 addr

This method converts a Bluetooth MAC address to an EUI64 address, which is used within IPv6 communication

Parameters

dst	IPv6 destination space
src	BLE MAC address source
public_addr	If the LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS option is set, bit 0x02 will be set if param=0 (no public addr); cleared otherwise

See also

LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS

eui64_to_ble_addr()

void eui64_to_ble_addr	(	uint8_t *	dst,
		const uint8_t *	src
	)

convert EUI64 address to Bluetooth MAC addr

This method converts an EUI64 address to a Bluetooth MAC address,

Parameters

dst	BLE MAC address destination
src	IPv6 source

rfc7668_if_init()

err_t rfc7668_if_init

(

struct netif *

netif

)

Initialize the netif

No flags are used (broadcast not possible, not ethernet, ...) The shortname for this netif is "BT"

Parameters

netif

the network interface to be initialized as RFC7668 netif

Returns

ERR_OK if everything went fine

rfc7668_input()

err_t rfc7668_input	(	struct pbuf *	p,
		struct netif *	netif
	)

Process a received raw payload from an L2CAP channel

Parameters

p	the received packet, p->payload pointing to the IPv6 header (maybe compressed)
netif	the network interface on which the packet was received

Returns

ERR_OK if everything was fine

rfc7668_output()

err_t rfc7668_output	(	struct netif *	netif,
		struct pbuf *	q,
		const ip6_addr_t *	ip6addr
	)

Compress outgoing IPv6 packet and pass it on to netif->linkoutput

Parameters

netif	The lwIP network interface which the IP packet will be sent on.
q	The pbuf(s) containing the IP packet to be sent.
ip6addr	The IP address of the packet destination.

Returns

See rfc7668_compress

rfc7668_set_context()

err_t rfc7668_set_context	(	u8_t	idx,
		const ip6_addr_t *	context
	)

Set context id IPv6 address

Store one IPv6 address to a given context id.

Parameters

idx	Context id
context	IPv6 addr for this context

Returns

ERR_OK (if everything is fine), ERR_ARG (if the context id is out of range), ERR_VAL (if contexts disabled)