Crate bacnet_npdu 

The BACnet network-layer vocabulary (Clause 6), in one place, for every layer of rusty-bacnet and for firmware.

The crate is no_std, needs no allocator and has no dependencies. It holds what the portable cores, the hosted transports and network layer, and the owned codec of bacnet-encoding all speak, so each concept has one definition:

• Npdu: a borrowed view of an NPDU’s control information and its payload. Npdu::decode reads one in place, telling an address too long for any data link (DecodeError::AddressTooLong) apart from every other fault (Malformed); Npdu::encoded_len and Npdu::encode_into write one into the caller’s buffer, refusing anything the decoder would refuse before writing an octet.
• NetworkMessageType and RejectMessageReason: the open sets of wire codes for network-layer messages and their reject reasons.
• RejectMessageToNetwork: a reject’s data, its reason and network, read and written in place, refused with RejectLengthError when it isn’t three octets.
• NetworkPriority: the closed, two-bit network priority.
• NpduLimits: the longest NPDU a link carries each way, and MAX_NPDU, the longest any data link here carries.
• Mac: a link-layer address of up to MAX_MAC_LEN octets, stored inline.

The other network-layer messages’ payloads, the routing table and the router itself are bacnet-router-core’s.

Example

use bacnet_npdu::{Address, Npdu, NetworkPriority};

// A confirmed request for station 5 on network 2, at urgent priority.
let mut request = Npdu::apdu(&[0x00, 0x05, 0x01, 0x0C]);
request.destination = Some(Address { network: 2, mac: &[5] });
request.expecting_reply = true;
request.priority = NetworkPriority::Urgent;

let mut frame = [0u8; 32];
let len = request.encode_into(&mut frame)?;
assert_eq!(len, request.encoded_len());
assert_eq!(&frame[..len], &[0x01, 0x25, 0x00, 0x02, 0x01, 0x05, 0xFF, 0x00, 0x05, 0x01, 0x0C]);

let decoded = Npdu::decode(&frame[..len]).expect("an NPDU");
assert_eq!(decoded.destination, request.destination);
assert_eq!(decoded.priority, NetworkPriority::Urgent);
assert_eq!(decoded.payload, request.payload);

Structs

Address

A network and a MAC on it: a DNET and DADR, or an SNET and SADR.

Mac

A link-layer address of up to MAX_MAC_LEN octets, stored inline, so a route or a pending reply holds one without an allocator.

MacTooLong

A MAC longer than MAX_MAC_LEN octets was offered to Mac.

NetworkMessageType

A network-layer message type: the octet after an NPDU’s addresses that says which message it carries (Clause 6.2.4).

Npdu

An NPDU’s control information, with its payload, borrowed from a frame.

NpduLimits

The longest NPDU a link carries, in octets, to one node and to every node on it (Table 6-1).

PriorityError

A value NetworkPriority::try_from refuses: a network priority is two bits, 0 to 3.

RejectLengthError

A Reject-Message-To-Network’s data isn’t RejectMessageToNetwork::LEN octets: it ends inside the network, or goes on past it.

RejectMessageReason

The reason a Reject-Message-To-Network gives (Clause 6.4.4).

RejectMessageToNetwork

What a Reject-Message-To-Network carries after its type (Clause 6.4.4): one reason octet, then the two-octet network the refused message was for.

Enums

AddressField

Which address a DecodeError::AddressTooLong concerns.

DecodeError

Why Npdu::decode refused a frame.

EncodeError

Why Npdu::encode_into refused an NPDU. Nothing was written.

Malformed

What made a frame malformed.

NetworkPriority

An NPDU’s network priority (Clause 6.2.2): the control octet’s two low bits, in increasing order of urgency.

Constants

GLOBAL_NETWORK

The DNET of a global broadcast.

MAX_MAC_LEN

The longest DADR, SADR or link MAC the stack accepts, in octets (#1141).

MAX_NPDU

The longest NPDU, in octets, that B/IP, B/IPv6, Ethernet and MS/TP with extended frames carry (Table 6-1; Clause 9.3 for MS/TP).

VERSION

The protocol version every NPDU starts with.