netstack_testing_common/
packets.rs

1// Copyright 2022 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5//! Packet parsing helpers.
6
7#![warn(missing_docs)]
8
9use packet::ParsablePacket as _;
10
11/// Parse a packet as a DHCPv6 message.
12///
13/// Returns `None` if the packet is not DHCPv6 in UDP in IPv6 in Ethernet.
14///
15/// # Panics
16///
17/// Panics if parsing fails at any layer.
18pub fn parse_dhcpv6(mut buf: &[u8]) -> Option<packet_formats_dhcp::v6::Message<'_, &[u8]>> {
19    let eth = packet_formats::ethernet::EthernetFrame::parse(
20        &mut buf,
21        packet_formats::ethernet::EthernetFrameLengthCheck::NoCheck,
22    )
23    .expect("failed to parse ethernet frame");
24
25    match eth.ethertype().expect("ethertype missing") {
26        packet_formats::ethernet::EtherType::Ipv6 => {}
27        packet_formats::ethernet::EtherType::Ipv4
28        | packet_formats::ethernet::EtherType::Arp
29        | packet_formats::ethernet::EtherType::Other(_) => {
30            return None;
31        }
32    }
33
34    let (mut ipv6_body, src_ip, dst_ip, proto, _ttl) =
35        packet_formats::testutil::parse_ip_packet::<net_types::ip::Ipv6>(buf)
36            .expect("error parsing IPv6 packet");
37    if proto != packet_formats::ip::Ipv6Proto::Proto(packet_formats::ip::IpProto::Udp) {
38        return None;
39    }
40
41    let udp_packet = packet_formats::udp::UdpPacket::parse(
42        &mut ipv6_body,
43        packet_formats::udp::UdpParseArgs::new(src_ip, dst_ip),
44    )
45    .expect("error parsing UDP datagram");
46
47    let mut udp_body = udp_packet.into_body();
48    Some(
49        packet_formats_dhcp::v6::Message::parse(&mut udp_body, ())
50            .expect("error parsing as DHCPv6 message"),
51    )
52}
netstack_testing_common/packets.rs

netstack_testing_common/
packets.rs
