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Implement IPv4 packet support.

v0.7.x
whitequark 2016-12-12 17:26:06 +00:00
parent 7f1b88ef45
commit 921ca353b4
7 changed files with 415 additions and 18 deletions
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4
src/iface/ethernet.rs
View File

@ -111,8 +111,8 @@ impl<'a, DeviceT: Device, ArpCacheT: ArpCache> Interface<'a, DeviceT, ArpCacheT>
let tx_size = self.device.mtu();
let tx_buffer = try!(self.device.transmit(tx_size));
let mut frame = try!(EthernetFrame::new(tx_buffer));
frame.set_source(self.hardware_addr);
frame.set_destination(match repr {
frame.set_src_addr(self.hardware_addr);
frame.set_dst_addr(match repr {
ArpRepr::EthernetIpv4 { target_hardware_addr, .. } => target_hardware_addr,
_ => unreachable!()
});

7
src/lib.rs
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@ -1,4 +1,4 @@
#![feature(associated_consts, const_fn)]
#![feature(associated_consts, const_fn, step_by)]
#![no_std]
extern crate byteorder;
@ -21,8 +21,10 @@ pub enum Error {
/// A packet could not be parsed or emitted because a field was out of bounds
/// for the underlying buffer.
Truncated,
/// A packet could not be recognized and was dropped.
/// An incoming packet could not be recognized and was dropped.
Unrecognized,
/// An incoming packet had an incorrect checksum and was dropped.
Checksum,
#[doc(hidden)]
__Nonexhaustive
@ -33,6 +35,7 @@ impl fmt::Display for Error {
match self {
&Error::Truncated => write!(f, "truncated packet"),
&Error::Unrecognized => write!(f, "unrecognized packet"),
&Error::Checksum => write!(f, "checksum error"),
&Error::__Nonexhaustive => unreachable!()
}
}

14
src/wire/arp.rs
View File

@ -19,7 +19,7 @@ enum_with_unknown! {
}
}
/// A read/write wrapper around an Address Resolution Protocol packet.
/// A read/write wrapper around an Address Resolution Protocol packet buffer.
#[derive(Debug)]
pub struct Packet<T: AsRef<[u8]>> {
buffer: T
@ -28,7 +28,7 @@ pub struct Packet<T: AsRef<[u8]>> {
mod field {
#![allow(non_snake_case)]
use ::wire::field::*;
use wire::field::*;
pub const HTYPE: Field = 0..2;
pub const PTYPE: Field = 2..4;
@ -84,6 +84,7 @@ impl<T: AsRef<[u8]>> Packet<T> {
}
/// Return the hardware type field.
#[inline(always)]
pub fn hardware_type(&self) -> HardwareType {
let data = self.buffer.as_ref();
let raw = NetworkEndian::read_u16(&data[field::HTYPE]);
@ -91,6 +92,7 @@ impl<T: AsRef<[u8]>> Packet<T> {
}
/// Return the protocol type field.
#[inline(always)]
pub fn protocol_type(&self) -> ProtocolType {
let data = self.buffer.as_ref();
let raw = NetworkEndian::read_u16(&data[field::PTYPE]);
@ -98,18 +100,21 @@ impl<T: AsRef<[u8]>> Packet<T> {
}
/// Return the hardware length field.
#[inline(always)]
pub fn hardware_len(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::HLEN]
}
/// Return the protocol length field.
#[inline(always)]
pub fn protocol_len(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::PLEN]
}
/// Return the operation field.
#[inline(always)]
pub fn operation(&self) -> Operation {
let data = self.buffer.as_ref();
let raw = NetworkEndian::read_u16(&data[field::OPER]);
@ -143,30 +148,35 @@ impl<T: AsRef<[u8]>> Packet<T> {
impl<T: AsRef<[u8]> + AsMut<[u8]>> Packet<T> {
/// Set the hardware type field.
#[inline(always)]
pub fn set_hardware_type(&mut self, value: HardwareType) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::HTYPE], value.into())
}
/// Set the protocol type field.
#[inline(always)]
pub fn set_protocol_type(&mut self, value: ProtocolType) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::PTYPE], value.into())
}
/// Set the hardware length field.
#[inline(always)]
pub fn set_hardware_len(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::HLEN] = value
}
/// Set the protocol length field.
#[inline(always)]
pub fn set_protocol_len(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::PLEN] = value
}
/// Set the operation field.
#[inline(always)]
pub fn set_operation(&mut self, value: Operation) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::OPER], value.into())

24
src/wire/ethernet.rs
View File

@ -17,7 +17,7 @@ impl fmt::Display for EtherType {
&EtherType::Ipv4 => write!(f, "IPv4"),
&EtherType::Ipv6 => write!(f, "IPv6"),
&EtherType::Arp => write!(f, "ARP"),
&EtherType::Unknown(ty) => write!(f, "0x{:04x}", ty)
&EtherType::Unknown(id) => write!(f, "0x{:04x}", id)
}
}
}
@ -63,14 +63,14 @@ impl fmt::Display for Address {
}
}
/// A read/write wrapper around an Ethernet II frame.
/// A read/write wrapper around an Ethernet II frame buffer.
#[derive(Debug)]
pub struct Frame<T: AsRef<[u8]>> {
buffer: T
}
mod field {
use ::wire::field::*;
use wire::field::*;
pub const DESTINATION: Field = 0..6;
pub const SOURCE: Field = 6..12;
@ -97,14 +97,14 @@ impl<T: AsRef<[u8]>> Frame<T> {
/// Return the destination address field.
#[inline(always)]
pub fn destination(&self) -> Address {
pub fn dst_addr(&self) -> Address {
let data = self.buffer.as_ref();
Address::from_bytes(&data[field::DESTINATION])
}
/// Return the source address field.
#[inline(always)]
pub fn source(&self) -> Address {
pub fn src_addr(&self) -> Address {
let data = self.buffer.as_ref();
Address::from_bytes(&data[field::SOURCE])
}
@ -128,14 +128,14 @@ impl<T: AsRef<[u8]>> Frame<T> {
impl<T: AsRef<[u8]> + AsMut<[u8]>> Frame<T> {
/// Set the destination address field.
#[inline(always)]
pub fn set_destination(&mut self, value: Address) {
pub fn set_dst_addr(&mut self, value: Address) {
let data = self.buffer.as_mut();
data[field::DESTINATION].copy_from_slice(value.as_bytes())
}
/// Set the source address field.
#[inline(always)]
pub fn set_source(&mut self, value: Address) {
pub fn set_src_addr(&mut self, value: Address) {
let data = self.buffer.as_mut();
data[field::SOURCE].copy_from_slice(value.as_bytes())
}
@ -158,7 +158,7 @@ impl<T: AsRef<[u8]> + AsMut<[u8]>> Frame<T> {
impl<T: AsRef<[u8]>> fmt::Display for Frame<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "EthernetII src={} dst={} type={}",
self.source(), self.destination(), self.ethertype())
self.src_addr(), self.dst_addr(), self.ethertype())
}
}
@ -210,8 +210,8 @@ mod test {
#[test]
fn test_deconstruct() {
let frame = Frame::new(&FRAME_BYTES[..]).unwrap();
assert_eq!(frame.destination(), Address([0x01, 0x02, 0x03, 0x04, 0x05, 0x06]));
assert_eq!(frame.source(), Address([0x11, 0x12, 0x13, 0x14, 0x15, 0x16]));
assert_eq!(frame.dst_addr(), Address([0x01, 0x02, 0x03, 0x04, 0x05, 0x06]));
assert_eq!(frame.src_addr(), Address([0x11, 0x12, 0x13, 0x14, 0x15, 0x16]));
assert_eq!(frame.ethertype(), EtherType::Ipv4);
assert_eq!(frame.payload(), &PAYLOAD_BYTES[..]);
}
@ -220,8 +220,8 @@ mod test {
fn test_construct() {
let mut bytes = vec![0; 64];
let mut frame = Frame::new(&mut bytes).unwrap();
frame.set_destination(Address([0x01, 0x02, 0x03, 0x04, 0x05, 0x06]));
frame.set_source(Address([0x11, 0x12, 0x13, 0x14, 0x15, 0x16]));
frame.set_dst_addr(Address([0x01, 0x02, 0x03, 0x04, 0x05, 0x06]));
frame.set_src_addr(Address([0x11, 0x12, 0x13, 0x14, 0x15, 0x16]));
frame.set_ethertype(EtherType::Ipv4);
frame.payload_mut().copy_from_slice(&PAYLOAD_BYTES[..]);
assert_eq!(&frame.into_inner()[..], &FRAME_BYTES[..]);

21
src/wire/ip.rs Normal file
View File

@ -0,0 +1,21 @@
use core::fmt;
enum_with_unknown! {
/// Internet protocol type.
pub enum ProtocolType(u8) {
Icmp = 0x01,
Tcp = 0x06,
Udp = 0x11
}
}
impl fmt::Display for ProtocolType {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
&ProtocolType::Icmp => write!(f, "ICMP"),
&ProtocolType::Tcp => write!(f, "TCP"),
&ProtocolType::Udp => write!(f, "UDP"),
&ProtocolType::Unknown(id) => write!(f, "0x{:02x}", id)
}
}
}

359
src/wire/ipv4.rs
View File

@ -1,4 +1,8 @@
use core::fmt;
use byteorder::{ByteOrder, NetworkEndian};
use Error;
pub use super::InternetProtocolType as ProtocolType;
/// A four-octet IPv4 address.
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default)]
@ -61,3 +65,358 @@ impl fmt::Display for Address {
write!(f, "{}.{}.{}.{}", bytes[0], bytes[1], bytes[2], bytes[3])
}
}
/// A read/write wrapper around an Internet Protocol version 4 packet buffer.
#[derive(Debug)]
pub struct Packet<T: AsRef<[u8]>> {
buffer: T
}
mod field {
#![allow(non_snake_case)]
use wire::field::*;
pub const VER_IHL: usize = 0;
pub const DSCP_ECN: usize = 1;
pub const LENGTH: Field = 2..4;
pub const IDENT: Field = 4..6;
pub const FLG_OFF1: usize = 6;
pub const FLG_OFF0: usize = 7;
pub const TTL: usize = 8;
pub const PROTOCOL: usize = 9;
pub const CHECKSUM: Field = 10..12;
pub const SRC_ADDR: Field = 12..16;
pub const DST_ADDR: Field = 16..20;
}
fn checksum(data: &[u8]) -> u16 {
let mut accum: u32 = 0;
for i in (0..data.len()).step_by(2) {
if i == field::CHECKSUM.start { continue }
let word = NetworkEndian::read_u16(&data[i..i + 2]) as u32;
accum += word;
}
!(((accum >> 16) as u16) + (accum as u16))
}
impl<T: AsRef<[u8]>> Packet<T> {
/// Wrap a buffer with an IPv4 packet. Returns an error if the buffer
/// is too small to contain one.
pub fn new(buffer: T) -> Result<Packet<T>, Error> {
let len = buffer.as_ref().len();
if len < field::VER_IHL {
Err(Error::Truncated)
} else {
let packet = Packet { buffer: buffer };
if len < packet.header_len() as usize {
Err(Error::Truncated)
} else {
Ok(packet)
}
}
}
/// Consumes the packet, returning the underlying buffer.
pub fn into_inner(self) -> T {
self.buffer
}
/// Return the version field.
#[inline(always)]
pub fn version(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::VER_IHL] & 0x04
}
/// Return the header length, in octets.
#[inline(always)]
pub fn header_len(&self) -> u8 {
let data = self.buffer.as_ref();
(data[field::VER_IHL] >> 4) * 4
}
/// Return the Differential Services Code Point field.
pub fn dscp(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::DSCP_ECN] & 0x3f
}
/// Return the Explicit Congestion Notification field.
pub fn ecn(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::DSCP_ECN] >> 6
}
/// Return the total length field.
#[inline(always)]
pub fn total_len(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::LENGTH])
}
/// Return the fragment identification field.
#[inline(always)]
pub fn ident(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::IDENT])
}
/// Return the "don't fragment" flag.
#[inline(always)]
pub fn dont_frag(&self) -> bool {
let data = self.buffer.as_ref();
data[field::FLG_OFF1] & 0x02 != 0
}
/// Return the "more fragments" flag.
#[inline(always)]
pub fn more_frags(&self) -> bool {
let data = self.buffer.as_ref();
data[field::FLG_OFF1] & 0x04 != 0
}
/// Return the fragment offset, in octets.
#[inline(always)]
pub fn frag_offset(&self) -> u16 {
let data = self.buffer.as_ref();
let chunks = (((data[field::FLG_OFF1] >> 3) as u16) << 8) |
data[field::FLG_OFF0] as u16;
chunks * 8
}
/// Return the time to live field.
#[inline(always)]
pub fn ttl(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::TTL]
}
/// Return the protocol field.
#[inline(always)]
pub fn protocol(&self) -> ProtocolType {
let data = self.buffer.as_ref();
ProtocolType::from(data[field::PROTOCOL])
}
/// Return the header checksum field.
#[inline(always)]
pub fn checksum(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::CHECKSUM])
}
/// Return the source address field.
#[inline(always)]
pub fn src_addr(&self) -> Address {
let data = self.buffer.as_ref();
Address::from_bytes(&data[field::SRC_ADDR])
}
/// Return the destination address field.
#[inline(always)]
pub fn dst_addr(&self) -> Address {
let data = self.buffer.as_ref();
Address::from_bytes(&data[field::DST_ADDR])
}
/// Return a pointer to the payload.
#[inline(always)]
pub fn payload(&self) -> &[u8] {
let range = self.header_len() as usize;
let data = self.buffer.as_ref();
&data[range..]
}
/// Validate the header checksum.
pub fn verify_checksum(&self) -> bool {
let checksum = {
let data = self.buffer.as_ref();
checksum(&data[..self.header_len() as usize])
};
self.checksum() == checksum
}
}
impl<T: AsRef<[u8]> + AsMut<[u8]>> Packet<T> {
/// Set the version field.
#[inline(always)]
pub fn set_version(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::VER_IHL] = (data[field::VER_IHL] & !0x04) | (value & 0x04);
}
/// Set the header length, in octets.
#[inline(always)]
pub fn set_header_len(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::VER_IHL] = (data[field::VER_IHL] & !0x40) | ((value / 4) << 4);
}
/// Set the Differential Services Code Point field.
pub fn set_dscp(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::DSCP_ECN] = (data[field::DSCP_ECN] & !0x3f) | (value & 0x3f)
}
/// Set the Explicit Congestion Notification field.
pub fn set_ecn(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::DSCP_ECN] = (data[field::DSCP_ECN] & 0x3f) | (value << 6)
}
/// Set the total length field.
#[inline(always)]
pub fn set_total_len(&mut self, value: u16) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::LENGTH], value)
}
/// Set the fragment identification field.
#[inline(always)]
pub fn set_ident(&mut self, value: u16) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::IDENT], value)
}
/// Set the "don't fragment" flag.
#[inline(always)]
pub fn set_dont_frag(&mut self, value: bool) {
let data = self.buffer.as_mut();
let raw = data[field::FLG_OFF1];
data[field::FLG_OFF1] = if value { raw | 0x02 } else { raw & !0x02 };
}
/// Set the "more fragments" flag.
#[inline(always)]
pub fn set_more_frags(&mut self, value: bool) {
let data = self.buffer.as_mut();
let raw = data[field::FLG_OFF1];
data[field::FLG_OFF1] = if value { raw | 0x04 } else { raw & !0x04 };
}
/// Set the fragment offset, in octets.
#[inline(always)]
pub fn set_frag_offset(&mut self, value: u16) {
let data = self.buffer.as_mut();
let chunks = value / 8;
let raw = data[field::FLG_OFF1] & 0x7;
data[field::FLG_OFF1] = raw | (((chunks >> 8) << 3) as u8);
data[field::FLG_OFF0] = chunks as u8;
}
/// Set the time to live field.
#[inline(always)]
pub fn set_ttl(&mut self, value: u8) {
let data = self.buffer.as_mut();
data[field::TTL] = value
}
/// Set the protocol field.
#[inline(always)]
pub fn set_protocol(&mut self, value: ProtocolType) {
let data = self.buffer.as_mut();
data[field::PROTOCOL] = value.into()
}
/// Set the header checksum field.
#[inline(always)]
pub fn set_checksum(&mut self, value: u16) {
let data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::CHECKSUM], value)
}
/// Set the source address field.
#[inline(always)]
pub fn set_src_addr(&mut self, value: Address) {
let data = self.buffer.as_mut();
data[field::SRC_ADDR].copy_from_slice(value.as_bytes())
}
/// Set the destination address field.
#[inline(always)]
pub fn set_dst_addr(&mut self, value: Address) {
let data = self.buffer.as_mut();
data[field::DST_ADDR].copy_from_slice(value.as_bytes())
}
/// Return a mutable pointer to the payload.
#[inline(always)]
pub fn payload_mut(&mut self) -> &mut [u8] {
let range = self.header_len() as usize..;
let data = self.buffer.as_mut();
&mut data[range]
}
/// Compute and fill in the header checksum.
pub fn fill_checksum(&mut self) {
let checksum = {
let data = self.buffer.as_ref();
checksum(&data[..self.header_len() as usize])
};
self.set_checksum(checksum)
}
}
#[cfg(test)]
mod test {
use super::*;
static PACKET_BYTES: [u8; 30] =
[0x54, 0x00, 0x00, 0x1e,
0x01, 0x02, 0x16, 0x03,
0x1a, 0x01, 0x12, 0x6f,
0x11, 0x12, 0x13, 0x14,
0x21, 0x22, 0x23, 0x24,
0xaa, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0xff];
static PAYLOAD_BYTES: [u8; 10] =
[0xaa, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0xff];
#[test]
fn test_deconstruct() {
let packet = Packet::new(&PACKET_BYTES[..]).unwrap();
assert_eq!(packet.version(), 4);
assert_eq!(packet.header_len(), 20);
assert_eq!(packet.dscp(), 0);
assert_eq!(packet.ecn(), 0);
assert_eq!(packet.total_len(), 30);
assert_eq!(packet.ident(), 0x102);
assert_eq!(packet.more_frags(), true);
assert_eq!(packet.dont_frag(), true);
assert_eq!(packet.frag_offset(), 0x203 * 8);
assert_eq!(packet.ttl(), 0x1a);
assert_eq!(packet.protocol(), ProtocolType::Icmp);
assert_eq!(packet.checksum(), 0x126f);
assert_eq!(packet.src_addr(), Address([0x11, 0x12, 0x13, 0x14]));
assert_eq!(packet.dst_addr(), Address([0x21, 0x22, 0x23, 0x24]));
assert_eq!(packet.verify_checksum(), true);
assert_eq!(packet.payload(), &PAYLOAD_BYTES[..]);
}
#[test]
fn test_construct() {
let mut bytes = vec![0; 30];
let mut packet = Packet::new(&mut bytes).unwrap();
packet.set_version(4);
packet.set_header_len(20);
packet.set_dscp(0);
packet.set_ecn(0);
packet.set_total_len(30);
packet.set_ident(0x102);
packet.set_more_frags(true);
packet.set_dont_frag(true);
packet.set_frag_offset(0x203 * 8);
packet.set_ttl(0x1a);
packet.set_protocol(ProtocolType::Icmp);
packet.set_src_addr(Address([0x11, 0x12, 0x13, 0x14]));
packet.set_dst_addr(Address([0x21, 0x22, 0x23, 0x24]));
packet.fill_checksum();
packet.payload_mut().copy_from_slice(&PAYLOAD_BYTES[..]);
assert_eq!(&packet.into_inner()[..], &PACKET_BYTES[..]);
}
}

4
src/wire/mod.rs
View File

@ -59,6 +59,7 @@ pub mod pretty_print;
mod ethernet;
mod arp;
mod ip;
mod ipv4;
pub use self::pretty_print::PrettyPrinter;
@ -73,4 +74,7 @@ pub use self::arp::Operation as ArpOperation;
pub use self::arp::Packet as ArpPacket;
pub use self::arp::Repr as ArpRepr;
pub use self::ip::ProtocolType as InternetProtocolType;
pub use self::ipv4::Address as Ipv4Address;
pub use self::ipv4::Packet as Ipv4Packet;