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use super::super::*;
use crate::err::ipv6_exts::ExtPayloadLenError;
use arrayvec::ArrayVec;
use core::fmt::{Debug, Formatter};
/// Deprecated. Use [Ipv6RawExtHeader] instead.
#[deprecated(
since = "0.14.0",
note = "Please use the type Ipv6RawExtHeader instead"
)]
pub type Ipv6RawExtensionHeader = Ipv6RawExtHeader;
/// Raw IPv6 extension header (undecoded payload).
///
/// IPv6 extension header with only minimal data interpretation. NOTE only ipv6 header
/// extensions with the first two bytes representing the next header and the header length
/// in 8-octets (- 8 octets) can be represented with this struct. This excludes the "Authentication
/// Header" (AH) and "Encapsulating Security Payload" (ESP).
///
/// The following headers can be represented in a [`Ipv6RawExtHeader`]:
/// * Hop by Hop
/// * Destination Options
/// * Routing
/// * Mobility
/// * Host Identity Protocol
/// * Shim6 Protocol
#[derive(Clone)]
pub struct Ipv6RawExtHeader {
/// IP protocol number specifying the next header or transport layer protocol.
///
/// See [IpNumber] or [ip_number] for a definition of the known values.
pub next_header: IpNumber,
/// Length of the extension header in 8 octets (minus the first 8 octets).
header_length: u8,
//// The data contained in the extension header (excluding next_header & hdr length).
payload_buffer: [u8; 0xff * 8 + 6],
}
impl Debug for Ipv6RawExtHeader {
fn fmt(&self, f: &mut Formatter) -> Result<(), core::fmt::Error> {
let mut s = f.debug_struct("Ipv6RawExtHeader");
s.field("next_header", &self.next_header);
s.field("payload", &self.payload());
s.finish()
}
}
impl PartialEq for Ipv6RawExtHeader {
fn eq(&self, other: &Self) -> bool {
self.next_header == other.next_header && self.payload() == other.payload()
}
}
impl Eq for Ipv6RawExtHeader {}
impl Default for Ipv6RawExtHeader {
fn default() -> Self {
Ipv6RawExtHeader {
next_header: IpNumber(255),
header_length: 0,
payload_buffer: [0; 0xff * 8 + 6],
}
}
}
impl Ipv6RawExtHeader {
/// Minimum length of an raw IPv6 extension header in bytes/octets.
pub const MIN_LEN: usize = 8;
/// Maximum length of an raw IPv6 extension header in bytes/octets.
///
/// This number is calculated by multiplying the maximum "hdr ext len"
/// (0xff) with 8 and adding 8. As RFC8200 states that "hdr ext len" is
/// defined as "8-bit unsigned integer. Length of the Hop-by-Hop Options
/// header in 8-octet units, not including the first 8 octets."
pub const MAX_LEN: usize = 8 + (8 * 0xff);
/// Minimum length of a [Ipv6RawExtHeader] payload
pub const MIN_PAYLOAD_LEN: usize = 6;
/// Maximum length of a [Ipv6RawExtHeader] the payload
pub const MAX_PAYLOAD_LEN: usize = 0xff * 8 + 6;
/// Returns true if the given header type ip number can be represented in an `Ipv6ExtensionHeader`.
pub fn header_type_supported(next_header: IpNumber) -> bool {
use crate::ip_number::*;
matches!(
next_header,
IPV6_HOP_BY_HOP | IPV6_ROUTE | IPV6_DEST_OPTIONS | MOBILITY | HIP | SHIM6
)
}
/// Creates an generic IPv6 extension header with the given data.
///
/// # Arguments
///
/// * `next_header` - type of content after this header (protocol number)
/// * `payload` - slice containing the data of the header. This must NOT contain the `next header` and `extended header length` fields of the header.
///
/// Note that `payload` must have at least the length of 6 bytes and only supports
/// length increases in steps of 8. This measn that the following expression must be true `(payload.len() + 2) % 8 == 0`.
/// The maximum length of the payload is `2046` bytes ([`Ipv6RawExtHeader::MAX_PAYLOAD_LEN`]).
///
/// If a payload with a non supported length is provided a [`crate::err::ipv6_exts::ExtPayloadLenError`] is returned.
pub fn new_raw(
next_header: IpNumber,
payload: &[u8],
) -> Result<Ipv6RawExtHeader, ExtPayloadLenError> {
use ExtPayloadLenError::*;
if payload.len() < Self::MIN_PAYLOAD_LEN {
Err(TooSmall(payload.len()))
} else if payload.len() > Self::MAX_PAYLOAD_LEN {
Err(TooBig(payload.len()))
} else if 0 != (payload.len() + 2) % 8 {
Err(Unaligned(payload.len()))
} else {
let mut result = Ipv6RawExtHeader {
next_header,
header_length: ((payload.len() - 6) / 8) as u8,
payload_buffer: [0; Self::MAX_PAYLOAD_LEN],
};
result.payload_buffer[..payload.len()].copy_from_slice(payload);
Ok(result)
}
}
/// Read an Ipv6ExtensionHeader from a slice and return the header & unused parts of the slice.
pub fn from_slice(slice: &[u8]) -> Result<(Ipv6RawExtHeader, &[u8]), err::LenError> {
let s = Ipv6RawExtHeaderSlice::from_slice(slice)?;
let rest = &slice[s.slice().len()..];
let header = s.to_header();
Ok((header, rest))
}
/// Return a slice containing the current payload. This does NOT contain
/// the `next_header` and `header_length` fields. But everything after these
/// two fields.
pub fn payload(&self) -> &[u8] {
&self.payload_buffer[..(6 + usize::from(self.header_length) * 8)]
}
/// Sets the payload (content of the header after the `next_header` & `header_length` fields).
///
/// Note that `payload` must have at least the length of 6 bytes and only supports
/// length increases in steps of 8. This measn that the following expression must be true `(payload.len() + 2) % 8 == 0`.
/// The maximum length of the payload is `2046` bytes ([`crate::Ipv6RawExtHeader::MAX_PAYLOAD_LEN`]).
///
/// If a payload with a non supported length is provided a [`crate::err::ipv6_exts::ExtPayloadLenError`] is returned and the payload of the header is not changed.
pub fn set_payload(&mut self, payload: &[u8]) -> Result<(), ExtPayloadLenError> {
use ExtPayloadLenError::*;
if payload.len() < Self::MIN_PAYLOAD_LEN {
Err(TooSmall(payload.len()))
} else if payload.len() > Self::MAX_PAYLOAD_LEN {
Err(TooBig(payload.len()))
} else if 0 != (payload.len() + 2) % 8 {
Err(Unaligned(payload.len()))
} else {
self.payload_buffer[..payload.len()].copy_from_slice(payload);
self.header_length = ((payload.len() - 6) / 8) as u8;
Ok(())
}
}
/// Read an fragment header from the current reader position.
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
pub fn read<T: std::io::Read + std::io::Seek + Sized>(
reader: &mut T,
) -> Result<Ipv6RawExtHeader, std::io::Error> {
let (next_header, header_length) = {
let mut d: [u8; 2] = [0; 2];
reader.read_exact(&mut d)?;
(IpNumber(d[0]), d[1])
};
Ok(Ipv6RawExtHeader {
next_header,
header_length,
payload_buffer: {
let mut buffer = [0; 0xff * 8 + 6];
reader.read_exact(&mut buffer[..usize::from(header_length) * 8 + 6])?;
buffer
},
})
}
/// Read an fragment header from the current limited reader position.
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
pub fn read_limited<T: std::io::Read + std::io::Seek + Sized>(
reader: &mut crate::io::LimitedReader<T>,
) -> Result<Ipv6RawExtHeader, err::io::LimitedReadError> {
// set layer start
reader.start_layer(err::Layer::Ipv6ExtHeader);
// read next & len
let (next_header, header_length) = {
let mut d: [u8; 2] = [0; 2];
reader.read_exact(&mut d)?;
(IpNumber(d[0]), d[1])
};
Ok(Ipv6RawExtHeader {
next_header,
header_length,
payload_buffer: {
let mut buffer = [0; 0xff * 8 + 6];
reader.read_exact(&mut buffer[..usize::from(header_length) * 8 + 6])?;
buffer
},
})
}
/// Writes a given IPv6 extension header to the current position.
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
pub fn write<W: std::io::Write + Sized>(&self, writer: &mut W) -> Result<(), std::io::Error> {
writer.write_all(&[self.next_header.0, self.header_length])?;
writer.write_all(self.payload())?;
Ok(())
}
/// Returns the serialized header.
pub fn to_bytes(&self) -> ArrayVec<u8, { Ipv6RawExtHeader::MAX_LEN }> {
let mut result = ArrayVec::new();
result.extend([self.next_header.0, self.header_length]);
// Unwrap Panic Safety:
// The following unwrap should never panic, as
// the payload length can at most have the size max
// header length - 2 and as the internal buffer used to
// store the payload data has exactly this size.
result.try_extend_from_slice(self.payload()).unwrap();
result
}
/// Length of the header in bytes.
pub fn header_len(&self) -> usize {
2 + (6 + usize::from(self.header_length) * 8)
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::test_gens::*;
use alloc::{format, vec::Vec};
use proptest::prelude::*;
use std::io::Cursor;
#[test]
fn default() {
let default_header = Ipv6RawExtHeader {
..Default::default()
};
assert_eq!(default_header.next_header, IpNumber(255));
assert_eq!(default_header.header_length, 0);
assert_eq!(default_header.payload_buffer, [0; 0xff * 8 + 6])
}
proptest! {
#[test]
fn debug(header in ipv6_raw_ext_any()) {
assert_eq!(
format!("{:?}", header),
format!(
"Ipv6RawExtHeader {{ next_header: {:?}, payload: {:?} }}",
header.next_header,
header.payload()
)
);
}
}
proptest! {
#[test]
fn clone_eq(header in ipv6_raw_ext_any()) {
assert_eq!(header.clone(), header);
}
}
#[test]
fn header_type_supported() {
use ip_number::*;
for value in 0..=u8::MAX {
let expected_supported = match IpNumber(value) {
IPV6_HOP_BY_HOP | IPV6_DEST_OPTIONS | IPV6_ROUTE | MOBILITY | HIP | SHIM6 => true,
_ => false,
};
assert_eq!(
expected_supported,
Ipv6RawExtHeader::header_type_supported(IpNumber(value))
);
}
}
proptest! {
#[test]
fn new_raw(header in ipv6_raw_ext_any()) {
use ExtPayloadLenError::*;
// ok
{
let actual = Ipv6RawExtHeader::new_raw(header.next_header, header.payload()).unwrap();
assert_eq!(actual.next_header, header.next_header);
assert_eq!(actual.payload(), header.payload());
}
// smaller then minimum
for len in 0..Ipv6RawExtHeader::MIN_PAYLOAD_LEN {
assert_eq!(
Ipv6RawExtHeader::new_raw(header.next_header, &header.payload()[..len]).unwrap_err(),
TooSmall(len)
);
}
// bigger then maximum
{
let bytes = [0u8;Ipv6RawExtHeader::MAX_PAYLOAD_LEN + 1];
assert_eq!(
Ipv6RawExtHeader::new_raw(header.next_header, &bytes).unwrap_err(),
TooBig(bytes.len())
);
}
// non aligned payload
{
let mut bytes = header.to_bytes();
bytes.pop().unwrap();
bytes.pop().unwrap();
for offset in 1..8 {
if offset + header.header_len() < Ipv6RawExtHeader::MAX_LEN {
bytes.push(0);
assert_eq!(
Ipv6RawExtHeader::new_raw(header.next_header, &bytes).unwrap_err(),
Unaligned(bytes.len())
);
}
}
}
}
}
proptest! {
#[test]
fn from_slice(header in ipv6_raw_ext_any()) {
// ok
{
let mut bytes = Vec::with_capacity(header.header_len() + 2);
bytes.extend_from_slice(&header.to_bytes());
bytes.push(1);
bytes.push(2);
let (actual_header, actual_rest) = Ipv6RawExtHeader::from_slice(&bytes).unwrap();
assert_eq!(actual_header, header);
assert_eq!(actual_rest, &[1, 2]);
}
// length error
{
let bytes = header.to_bytes();
for len in 0..bytes.len() {
assert_eq!(
Ipv6RawExtHeader::from_slice(&bytes[..len]).unwrap_err(),
err::LenError{
required_len: if len < Ipv6RawExtHeader::MIN_LEN {
Ipv6RawExtHeader::MIN_LEN
} else {
header.header_len()
},
len: len,
len_source: LenSource::Slice,
layer: err::Layer::Ipv6ExtHeader,
layer_start_offset: 0,
}
);
}
}
}
}
proptest! {
#[test]
fn set_payload(
header_a in ipv6_raw_ext_any(),
header_b in ipv6_raw_ext_any()
) {
use ExtPayloadLenError::*;
// ok
{
let mut actual = header_a.clone();
actual.set_payload(header_b.payload()).unwrap();
assert_eq!(actual.payload(), header_b.payload());
}
// smaller then minimum
for len in 0..Ipv6RawExtHeader::MIN_PAYLOAD_LEN {
let mut actual = header_a.clone();
assert_eq!(
actual.set_payload(&header_b.payload()[..len]).unwrap_err(),
TooSmall(len)
);
assert_eq!(actual.payload(), header_a.payload());
}
// bigger then maximum
{
let bytes = [0u8;Ipv6RawExtHeader::MAX_PAYLOAD_LEN + 1];
let mut actual = header_a.clone();
assert_eq!(
actual.set_payload(&bytes).unwrap_err(),
TooBig(bytes.len())
);
}
// non aligned payload
{
let mut bytes = header_b.to_bytes();
bytes.pop().unwrap();
bytes.pop().unwrap();
for offset in 1..8 {
if offset + header_b.header_len() < Ipv6RawExtHeader::MAX_LEN {
bytes.push(0);
let mut actual = header_a.clone();
assert_eq!(
actual.set_payload(&bytes).unwrap_err(),
Unaligned(bytes.len())
);
}
}
}
}
}
proptest! {
#[test]
fn read(header in ipv6_raw_ext_any()) {
// ok
{
let bytes = header.to_bytes();
let mut cursor = Cursor::new(&bytes[..]);
let actual = Ipv6RawExtHeader::read(&mut cursor).unwrap();
assert_eq!(actual, header);
}
// length error
{
let bytes = header.to_bytes();
for len in 0..bytes.len() {
let mut cursor = Cursor::new(&bytes[..len]);
assert!(Ipv6RawExtHeader::read(&mut cursor).is_err());
}
}
}
}
proptest! {
#[test]
fn write(header in ipv6_raw_ext_any()) {
// ok case
{
let mut buffer = [0u8;Ipv6RawExtHeader::MAX_LEN];
let len = {
let mut cursor = Cursor::new(&mut buffer[..]);
header.write(&mut cursor).unwrap();
cursor.position() as usize
};
let (dec_header, dec_rest) = Ipv6RawExtHeader::from_slice(&buffer[..len]).unwrap();
assert_eq!(header, dec_header);
assert_eq!(dec_rest, &[]);
}
// length error
for len in 0..header.header_len() {
let mut buffer = [0u8;Ipv6RawExtHeader::MAX_LEN];
let mut cursor = Cursor::new(&mut buffer[..len]);
assert!(header.write(&mut cursor).is_err());
}
}
}
proptest! {
#[test]
fn to_bytes(header in ipv6_raw_ext_any()) {
let bytes = header.to_bytes();
assert_eq!(bytes[0], header.next_header.0);
assert_eq!(bytes[1], header.header_length);
assert_eq!(&bytes[2..], header.payload());
}
}
proptest! {
#[test]
fn header_len(header in ipv6_raw_ext_any()) {
assert_eq!(header.header_len(), header.to_bytes().len());
}
}
}