[−][src]Crate jnet

JNeT: japaric's network thingies

There's no IO stuff in this crate. If you are looking for sockets and the like check out the smoltcp crate.

This crate mainly contains an API to work with frames and packets in no_std context.

It doesn't provide you any real parser though; it simply provides an API to mutate or access the header and the payload of a frame / packet in place. This approach is the same as the one used in smoltcp. The difference is that the API of this crate uses type state to (a) avoid foot guns like sending an IPv4 packet with an invalid header checksum, and to (b) provide specialized APIs when the packet type, e.g. ICMP EchoRequest, is known.

If type state is not your cup of tea check out smoltcp's wire module; do note that, as of v0.4.0, smoltcp doesn't provide an API to work with CoAP messages whereas this crate does.

Examples

use jnet::{arp, ether};

let bytes = &[
    255, 255, 255, 255, 255, 255, // eth: destination
    120, 68, 118, 217, 106, 124, // eth: source
    8, 6, // eth: type
    0, 1, // arp: HTYPE = Ethernet
    8, 0, // arp: PTYPE = IPv4
    6, // arp: HLEN
    4, // arp: PLEN
    0, 2, // arp: OPER = Reply
    120, 68, 118, 217, 106, 124, // arp: SHA
    192, 168, 1, 1, // arp: SPA
    32, 24, 3, 1, 0, 0, // arp: THA
    192, 168, 1, 33, // arp: TPA
    0, 0, 0, 0, // eth: padding
];

let eth = ether::Frame::parse(&bytes[..]).unwrap();
let arp = arp::Packet::parse(eth.payload()).unwrap();

assert_eq!(arp.get_htype(), arp::HardwareType::Ethernet);
assert_eq!(arp.get_ptype(), ether::Type::Ipv4);
assert_eq!(arp.get_oper(), arp::Operation::Reply);

The general principle to building frames / packets / messages is to start with an (slightly) oversized buffer and then proceed to shrink it to the right length.

use jnet::{coap, ether, ipv4, mac, udp};

const MAC_SRC: mac::Addr = mac::Addr([0x20, 0x18, 0x03, 0x01, 0x00, 0x00]);
const MAC_DST: mac::Addr = mac::Addr([0x20, 0x18, 0x03, 0x13, 0x00, 0x00]);

const IP_SRC: ipv4::Addr = ipv4::Addr([192, 168, 1, 11]);
const IP_DST: ipv4::Addr = ipv4::Addr([192, 168, 1, 33]);

let mut bytes = [0; 60];
let mut buf = &mut bytes[..];

// clean slate Ethernet frame with a total length of 60 bytes
let mut eth = ether::Frame::new(buf);
eth.set_destination(MAC_DST);
eth.set_source(MAC_SRC);

eth.ipv4(|ip| {
    ip.set_source(IP_SRC);
    ip.set_destination(IP_DST);
    ip.udp(|udp| {
        udp.set_destination(coap::PORT);
        udp.coap(0, |mut coap| {
            coap.set_type(coap::Type::Confirmable);
            coap.set_code(coap::Method::Put);
            coap.add_option(coap::OptionNumber::UriPath, b"led");
            coap.set_payload(b"on")
        })
    });
});

// At this point the Ethernet frame has shrunk to the size of its contents
// The excess memory is inaccessible
assert_eq!(eth.len(), 53);

Modules

arp

ARP: Address Resolution Protocol

coap

CoAP: Constrained Application Protocol

ether

Ethernet II

icmp

ICMP: Internet Control Message Protocol

icmpv6

ICMPv6: Internet Control Message Protocol for IPv6

ieee802154

IEEE 802.15.4

ipv4

IPv4: Internet Protocol v4

ipv6

IPv6: Internet Protocol v6

mac

MAC: Medium Access Control

sixlowpan

6LoWPAN: IPv6 over Low-Power Wireless Personal Area Networks

udp

UDP: User Datagram Protocol

Enums

Invalid

[Type State] Invalid checksum

Unknown

[Type State] Unknown

Valid

[Type State] Valid checksum