NDISC: Improve the representation layer for NDISC
Each given NDISC packet type may only include one of a few options. Instead of including the options in the NDISC repr as a &[u8] include the packet types available options as `Option<T>`. Closes: #194 Approved by: whitequark
This commit is contained in:
Dan Robertson
Homu
parent
13fe5734ec
commit
867eb1b7f8
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@ -186,6 +186,8 @@ pub use self::ndisc::Repr as NdiscRepr;
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pub use self::ndiscoption::{NdiscOption,
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Repr as NdiscOptionRepr,
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Type as NdiscOptionType,
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PrefixInformation as NdiscPrefixInformation,
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RedirectedHeader as NdiscRedirectedHeader,
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PrefixInfoFlags as NdiscPrefixInfoFlags};
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pub use self::udp::{Packet as UdpPacket,
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@ -2,6 +2,8 @@ use byteorder::{ByteOrder, NetworkEndian};
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use {Error, Result};
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use super::icmpv6::{field, Message, NeighborFlags, Packet, RouterFlags};
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use wire::{EthernetAddress, Ipv6Repr, Ipv6Packet};
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use wire::{NdiscOption, NdiscOptionRepr, NdiscOptionType, NdiscPrefixInformation, NdiscRedirectedHeader};
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use time::Duration;
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use super::Ipv6Address;
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@ -185,7 +187,7 @@ impl<T: AsRef<[u8]> + AsMut<[u8]>> Packet<T> {
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub enum Repr<'a> {
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RouterSolicit {
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options: &'a [u8]
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lladdr: Option<EthernetAddress>
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},
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RouterAdvert {
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hop_limit: u8,
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@ -193,21 +195,24 @@ pub enum Repr<'a> {
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router_lifetime: Duration,
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reachable_time: Duration,
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retrans_time: Duration,
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options: &'a [u8]
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lladdr: Option<EthernetAddress>,
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mtu: Option<u32>,
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prefix_info: Option<NdiscPrefixInformation>
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},
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NeighborSolicit {
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target_addr: Ipv6Address,
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options: &'a [u8]
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lladdr: Option<EthernetAddress>
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},
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NeighborAdvert {
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flags: NeighborFlags,
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target_addr: Ipv6Address,
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options: &'a [u8]
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lladdr: Option<EthernetAddress>
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},
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Redirect {
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target_addr: Ipv6Address,
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dest_addr: Ipv6Address,
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options: &'a [u8]
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lladdr: Option<EthernetAddress>,
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redirected_hdr: Option<NdiscRedirectedHeader<'a>>
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}
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}
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@ -219,38 +224,100 @@ impl<'a> Repr<'a> {
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where T: AsRef<[u8]> + ?Sized {
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match packet.msg_type() {
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Message::RouterSolicit => {
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Ok(Repr::RouterSolicit {
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options: packet.payload()
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})
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let lladdr = if packet.payload().len() > 0 {
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let opt = NdiscOption::new_checked(packet.payload())?;
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match opt.option_type() {
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NdiscOptionType::SourceLinkLayerAddr => Some(opt.link_layer_addr()),
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_ => { return Err(Error::Unrecognized); }
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}
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} else {
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None
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};
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Ok(Repr::RouterSolicit { lladdr })
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},
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Message::RouterAdvert => {
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let mut offset = 0;
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let (mut lladdr, mut mtu, mut prefix_info) = (None, None, None);
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while packet.payload().len() - offset > 0 {
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let pkt = NdiscOption::new_checked(&packet.payload()[offset..])?;
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let opt = NdiscOptionRepr::parse(&pkt)?;
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match opt {
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NdiscOptionRepr::SourceLinkLayerAddr(addr) => lladdr = Some(addr),
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NdiscOptionRepr::Mtu(val) => mtu = Some(val),
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NdiscOptionRepr::PrefixInformation(info) => prefix_info = Some(info),
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_ => { return Err(Error::Unrecognized); }
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}
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offset += opt.buffer_len();
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}
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Ok(Repr::RouterAdvert {
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hop_limit: packet.current_hop_limit(),
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flags: packet.router_flags(),
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router_lifetime: packet.router_lifetime(),
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reachable_time: packet.reachable_time(),
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retrans_time: packet.retrans_time(),
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options: packet.payload()
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lladdr, mtu, prefix_info
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})
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},
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Message::NeighborSolicit => {
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let lladdr = if packet.payload().len() > 0 {
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let opt = NdiscOption::new_checked(packet.payload())?;
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match opt.option_type() {
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NdiscOptionType::SourceLinkLayerAddr => Some(opt.link_layer_addr()),
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_ => { return Err(Error::Unrecognized); }
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}
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} else {
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None
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};
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Ok(Repr::NeighborSolicit {
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target_addr: packet.target_addr(),
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options: packet.payload()
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target_addr: packet.target_addr(), lladdr
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})
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},
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Message::NeighborAdvert => {
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let lladdr = if packet.payload().len() > 0 {
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let opt = NdiscOption::new_checked(packet.payload())?;
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match opt.option_type() {
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NdiscOptionType::TargetLinkLayerAddr => Some(opt.link_layer_addr()),
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_ => { return Err(Error::Unrecognized); }
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}
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} else {
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None
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};
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Ok(Repr::NeighborAdvert {
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flags: packet.neighbor_flags(),
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target_addr: packet.target_addr(),
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options: packet.payload()
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lladdr
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})
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},
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Message::Redirect => {
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let mut offset = 0;
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let (mut lladdr, mut redirected_hdr) = (None, None);
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while packet.payload().len() - offset > 0 {
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let opt = NdiscOption::new_checked(&packet.payload()[offset..])?;
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match opt.option_type() {
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NdiscOptionType::SourceLinkLayerAddr => {
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lladdr = Some(opt.link_layer_addr());
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offset += 8;
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},
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NdiscOptionType::RedirectedHeader => {
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if opt.data_len() < 6 {
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return Err(Error::Truncated)
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} else {
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let ip_packet = Ipv6Packet::new(&opt.data()[offset + 8..]);
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let ip_repr = Ipv6Repr::parse(&ip_packet)?;
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let data = &opt.data()[offset + 8 + ip_repr.buffer_len()..];
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redirected_hdr = Some(NdiscRedirectedHeader {
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header: ip_repr, data
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});
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offset += 8 + ip_repr.buffer_len() + data.len();
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}
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}
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_ => { return Err(Error::Unrecognized); }
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}
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}
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Ok(Repr::Redirect {
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target_addr: packet.target_addr(),
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dest_addr: packet.dest_addr(),
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options: packet.payload()
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lladdr, redirected_hdr
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})
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},
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_ => Err(Error::Unrecognized)
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@ -259,17 +326,40 @@ impl<'a> Repr<'a> {
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pub fn buffer_len(&self) -> usize {
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match self {
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&Repr::RouterSolicit { options, .. } => {
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field::UNUSED.end + options.len()
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&Repr::RouterSolicit { lladdr } => {
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match lladdr {
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Some(_) => field::UNUSED.end + 8,
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None => field::UNUSED.end,
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}
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},
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&Repr::RouterAdvert { options, .. } => {
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field::RETRANS_TM.end + options.len()
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&Repr::RouterAdvert { lladdr, mtu, prefix_info, .. } => {
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let mut offset = 0;
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if lladdr.is_some() {
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offset += 8;
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}
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if mtu.is_some() {
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offset += 8;
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}
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if prefix_info.is_some() {
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offset += 32;
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}
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field::RETRANS_TM.end + offset
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},
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&Repr::NeighborSolicit { options, .. } | &Repr::NeighborAdvert { options, .. } => {
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field::TARGET_ADDR.end + options.len()
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&Repr::NeighborSolicit { lladdr, .. } | &Repr::NeighborAdvert { lladdr, .. } => {
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match lladdr {
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Some(_) => field::TARGET_ADDR.end + 8,
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None => field::TARGET_ADDR.end,
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}
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},
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&Repr::Redirect { options, .. } => {
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field::DEST_ADDR.end + options.len()
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&Repr::Redirect { lladdr, redirected_hdr, .. } => {
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let mut offset = 0;
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if lladdr.is_some() {
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offset += 8;
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}
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if let Some(NdiscRedirectedHeader { header, data }) = redirected_hdr {
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offset += 8 + header.buffer_len() + data.len();
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}
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field::DEST_ADDR.end + offset
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}
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}
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}
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@ -277,14 +367,18 @@ impl<'a> Repr<'a> {
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pub fn emit<T>(&self, packet: &mut Packet<&mut T>)
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where T: AsRef<[u8]> + AsMut<[u8]> + ?Sized {
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match self {
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&Repr::RouterSolicit { options } => {
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&Repr::RouterSolicit { lladdr } => {
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packet.set_msg_type(Message::RouterSolicit);
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packet.set_msg_code(0);
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packet.clear_reserved();
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packet.payload_mut().copy_from_slice(&options[..]);
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if let Some(lladdr) = lladdr {
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let mut opt_pkt = NdiscOption::new(packet.payload_mut());
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NdiscOptionRepr::SourceLinkLayerAddr(lladdr).emit(&mut opt_pkt);
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}
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},
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&Repr::RouterAdvert { hop_limit, flags, router_lifetime, reachable_time, retrans_time, options } => {
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&Repr::RouterAdvert { hop_limit, flags, router_lifetime, reachable_time,
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retrans_time, lladdr, mtu, prefix_info } => {
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packet.set_msg_type(Message::RouterAdvert);
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packet.set_msg_code(0);
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packet.set_current_hop_limit(hop_limit);
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@ -292,33 +386,64 @@ impl<'a> Repr<'a> {
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packet.set_router_lifetime(router_lifetime);
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packet.set_reachable_time(reachable_time);
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packet.set_retrans_time(retrans_time);
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packet.payload_mut().copy_from_slice(&options[..]);
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let mut offset = 0;
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if let Some(lladdr) = lladdr {
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let mut opt_pkt = NdiscOption::new(packet.payload_mut());
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NdiscOptionRepr::SourceLinkLayerAddr(lladdr).emit(&mut opt_pkt);
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offset += 8;
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}
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if let Some(mtu) = mtu {
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let mut opt_pkt = NdiscOption::new(&mut packet.payload_mut()[offset..]);
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NdiscOptionRepr::Mtu(mtu).emit(&mut opt_pkt);
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offset += 8;
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}
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if let Some(prefix_info) = prefix_info {
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let mut opt_pkt = NdiscOption::new(&mut packet.payload_mut()[offset..]);
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NdiscOptionRepr::PrefixInformation(prefix_info).emit(&mut opt_pkt)
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}
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},
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&Repr::NeighborSolicit { target_addr, options } => {
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&Repr::NeighborSolicit { target_addr, lladdr } => {
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packet.set_msg_type(Message::NeighborSolicit);
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packet.set_msg_code(0);
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packet.clear_reserved();
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packet.set_target_addr(target_addr);
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packet.payload_mut().copy_from_slice(&options[..]);
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if let Some(lladdr) = lladdr {
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let mut opt_pkt = NdiscOption::new(packet.payload_mut());
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NdiscOptionRepr::SourceLinkLayerAddr(lladdr).emit(&mut opt_pkt);
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}
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},
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&Repr::NeighborAdvert { flags, target_addr, options } => {
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&Repr::NeighborAdvert { flags, target_addr, lladdr } => {
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packet.set_msg_type(Message::NeighborAdvert);
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packet.set_msg_code(0);
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packet.clear_reserved();
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packet.set_neighbor_flags(flags);
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packet.set_target_addr(target_addr);
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packet.payload_mut().copy_from_slice(&options[..]);
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if let Some(lladdr) = lladdr {
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let mut opt_pkt = NdiscOption::new(packet.payload_mut());
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NdiscOptionRepr::TargetLinkLayerAddr(lladdr).emit(&mut opt_pkt);
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}
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},
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&Repr::Redirect { target_addr, dest_addr, options } => {
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&Repr::Redirect { target_addr, dest_addr, lladdr, redirected_hdr } => {
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packet.set_msg_type(Message::Redirect);
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packet.set_msg_code(0);
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packet.clear_reserved();
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packet.set_target_addr(target_addr);
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packet.set_dest_addr(dest_addr);
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packet.payload_mut().copy_from_slice(&options[..]);
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let offset = match lladdr {
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Some(lladdr) => {
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let mut opt_pkt = NdiscOption::new(packet.payload_mut());
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NdiscOptionRepr::TargetLinkLayerAddr(lladdr).emit(&mut opt_pkt);
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8
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},
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None => 0,
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};
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if let Some(redirected_hdr) = redirected_hdr {
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let mut opt_pkt = NdiscOption::new(&mut packet.payload_mut()[offset..]);
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NdiscOptionRepr::RedirectedHeader(redirected_hdr).emit(&mut opt_pkt);
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}
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},
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}
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}
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@ -348,7 +473,9 @@ mod test {
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router_lifetime: Duration::from_secs(900),
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reachable_time: Duration::from_millis(900),
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retrans_time: Duration::from_millis(900),
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options: &SOURCE_LINK_LAYER_OPT[..]
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lladdr: Some(EthernetAddress([0x52, 0x54, 0x00, 0x12, 0x34, 0x56])),
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mtu: None,
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prefix_info: None
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})
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}
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@ -391,23 +391,28 @@ impl<'a, T: AsRef<[u8]> + ?Sized> fmt::Display for NdiscOption<&'a T> {
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}
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}
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub struct PrefixInformation {
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pub prefix_len: u8,
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pub flags: PrefixInfoFlags,
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pub valid_lifetime: Duration,
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pub preferred_lifetime: Duration,
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pub prefix: Ipv6Address
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}
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub struct RedirectedHeader<'a> {
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pub header: Ipv6Repr,
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pub data: &'a [u8]
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}
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/// A high-level representation of an NDISC Option.
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub enum Repr<'a> {
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SourceLinkLayerAddr(EthernetAddress),
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TargetLinkLayerAddr(EthernetAddress),
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PrefixInformation {
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prefix_len: u8,
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flags: PrefixInfoFlags,
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valid_lifetime: Duration,
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preferred_lifetime: Duration,
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prefix: Ipv6Address
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},
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RedirectedHeader {
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header: Ipv6Repr,
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data: &'a [u8]
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},
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PrefixInformation(PrefixInformation),
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RedirectedHeader(RedirectedHeader<'a>),
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Mtu(u32),
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Unknown {
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type_: u8,
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@ -437,13 +442,13 @@ impl<'a> Repr<'a> {
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},
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Type::PrefixInformation => {
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if opt.data_len() == 4 {
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Ok(Repr::PrefixInformation {
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Ok(Repr::PrefixInformation(PrefixInformation {
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prefix_len: opt.prefix_len(),
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flags: opt.prefix_flags(),
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valid_lifetime: opt.valid_lifetime(),
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preferred_lifetime: opt.preferred_lifetime(),
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prefix: opt.prefix()
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})
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}))
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} else {
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Err(Error::Malformed)
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}
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@ -457,10 +462,10 @@ impl<'a> Repr<'a> {
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} else {
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let ip_packet = Ipv6Packet::new(&opt.data()[field::IP_DATA..]);
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let ip_repr = Ipv6Repr::parse(&ip_packet)?;
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Ok(Repr::RedirectedHeader {
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Ok(Repr::RedirectedHeader(RedirectedHeader {
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header: ip_repr,
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data: &opt.data()[field::IP_DATA + ip_repr.buffer_len()..]
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})
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}))
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}
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},
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Type::Mtu => {
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@ -485,9 +490,9 @@ impl<'a> Repr<'a> {
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match self {
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&Repr::SourceLinkLayerAddr(_) | &Repr::TargetLinkLayerAddr(_) =>
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field::LL_ADDR.end,
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&Repr::PrefixInformation { .. } =>
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&Repr::PrefixInformation(_) =>
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field::PREFIX.end,
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&Repr::RedirectedHeader { header, data } =>
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&Repr::RedirectedHeader(RedirectedHeader { header, data }) =>
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field::IP_DATA + header.buffer_len() + data.len(),
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&Repr::Mtu(_) =>
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field::MTU.end,
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@ -510,10 +515,10 @@ impl<'a> Repr<'a> {
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opt.set_data_len(1);
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opt.set_link_layer_addr(addr);
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},
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&Repr::PrefixInformation {
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&Repr::PrefixInformation(PrefixInformation {
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prefix_len, flags, valid_lifetime,
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preferred_lifetime, prefix
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} => {
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}) => {
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opt.clear_prefix_reserved();
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opt.set_option_type(Type::PrefixInformation);
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opt.set_data_len(4);
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@ -523,9 +528,9 @@ impl<'a> Repr<'a> {
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opt.set_preferred_lifetime(preferred_lifetime);
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opt.set_prefix(prefix);
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},
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&Repr::RedirectedHeader {
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&Repr::RedirectedHeader(RedirectedHeader {
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header, data
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} => {
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}) => {
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let data_len = data.len() / 8;
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opt.clear_redirected_reserved();
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opt.set_option_type(Type::RedirectedHeader);
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@ -559,16 +564,16 @@ impl<'a> fmt::Display for Repr<'a> {
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&Repr::TargetLinkLayerAddr(addr) => {
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write!(f, "TargetLinkLayer addr={}", addr)
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||||
},
|
||||
&Repr::PrefixInformation {
|
||||
&Repr::PrefixInformation(PrefixInformation {
|
||||
prefix, prefix_len,
|
||||
..
|
||||
} => {
|
||||
}) => {
|
||||
write!(f, "PrefixInformation prefix={}/{}", prefix, prefix_len)
|
||||
},
|
||||
&Repr::RedirectedHeader {
|
||||
&Repr::RedirectedHeader(RedirectedHeader {
|
||||
header,
|
||||
..
|
||||
} => {
|
||||
}) => {
|
||||
write!(f, "RedirectedHeader header={}", header)
|
||||
},
|
||||
&Repr::Mtu(mtu) => {
|
||||
|
|
@ -605,7 +610,7 @@ mod test {
|
|||
use Error;
|
||||
use time::Duration;
|
||||
use wire::{EthernetAddress, Ipv6Address};
|
||||
use super::{NdiscOption, Type, PrefixInfoFlags, Repr};
|
||||
use super::{NdiscOption, Type, PrefixInfoFlags, PrefixInformation, Repr};
|
||||
|
||||
static PREFIX_OPT_BYTES: [u8; 32] = [
|
||||
0x03, 0x04, 0x40, 0xc0,
|
||||
|
|
@ -671,26 +676,26 @@ mod test {
|
|||
|
||||
#[test]
|
||||
fn test_repr_parse_prefix_info() {
|
||||
let repr = Repr::PrefixInformation {
|
||||
let repr = Repr::PrefixInformation(PrefixInformation {
|
||||
prefix_len: 64,
|
||||
flags: PrefixInfoFlags::ON_LINK | PrefixInfoFlags::ADDRCONF,
|
||||
valid_lifetime: Duration::from_secs(900),
|
||||
preferred_lifetime: Duration::from_secs(1000),
|
||||
prefix: Ipv6Address::new(0xfe80, 0, 0, 0, 0, 0, 0, 1)
|
||||
};
|
||||
});
|
||||
assert_eq!(Repr::parse(&NdiscOption::new(&PREFIX_OPT_BYTES)), Ok(repr));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_repr_emit_prefix_info() {
|
||||
let mut bytes = [0x2a; 32];
|
||||
let repr = Repr::PrefixInformation {
|
||||
let repr = Repr::PrefixInformation(PrefixInformation {
|
||||
prefix_len: 64,
|
||||
flags: PrefixInfoFlags::ON_LINK | PrefixInfoFlags::ADDRCONF,
|
||||
valid_lifetime: Duration::from_secs(900),
|
||||
preferred_lifetime: Duration::from_secs(1000),
|
||||
prefix: Ipv6Address::new(0xfe80, 0, 0, 0, 0, 0, 0, 1)
|
||||
};
|
||||
});
|
||||
let mut opt = NdiscOption::new(&mut bytes);
|
||||
repr.emit(&mut opt);
|
||||
assert_eq!(&opt.into_inner()[..], &PREFIX_OPT_BYTES[..]);
|
||||
|
|
|
|||
Loading…
Reference in New Issue