step

lib/dnsbox-base/src/common_types/classes.rs

@@ -133,7 +133,6 @@ impl Class {
 	///
 	/// Avoids conflict with parsing RRTYPE mnemonics.
 	pub fn from_known_name_without_any(name: &str) -> Option<Self> {
-		use std::ascii::AsciiExt;
 		if name.eq_ignore_ascii_case("IN") { return Some(IN); }
 		if name.eq_ignore_ascii_case("CH") { return Some(CH); }
 		if name.eq_ignore_ascii_case("HS") { return Some(HS); }
@@ -143,7 +142,6 @@ impl Class {
 
 	/// parses known names (mnemonics)
 	pub fn from_known_name(name: &str) -> Option<Self> {
-		use std::ascii::AsciiExt;
 		Self::from_known_name_without_any(name).or_else(|| {
 			if name.eq_ignore_ascii_case("ANY") { return Some(ANY); }
 			None
@@ -152,7 +150,6 @@ impl Class {
 
 	/// parses generic names of the form "CLASS..."
 	pub fn from_generic_name(name: &str) -> Option<Self> {
-		use std::ascii::AsciiExt;
 		if name.len() > 5 && name.as_bytes()[0..5].eq_ignore_ascii_case(b"CLASS") {
 			name[5..].parse::<u16>().ok().map(Class)
 		} else {

lib/dnsbox-base/src/common_types/name/canonical_name.rs

@@ -0,0 +1,127 @@
+use bytes::Bytes;
+use errors::*;
+use ser::packet::{DnsPacketData, DnsPacketWriteContext};
+use ser::text::{DnsTextData, DnsTextFormatter, DnsTextContext, next_field, parse_with};
+use std::fmt;
+use std::io::Cursor;
+use std::ops::{Deref, DerefMut};
+use std::str::FromStr;
+
+use super::{DnsName, DnsNameIterator, DnsLabelRef};
+
+/// names that should be written in canonical form for DNSSEC according
+/// to https://tools.ietf.org/html/rfc4034#section-6.2
+///
+/// DnsCompressedName always needs to be written in canonical form for
+/// DNSSEC.
+#[derive(Clone)]
+pub struct DnsCanonicalName(pub DnsName);
+
+impl DnsCanonicalName {
+	/// Create new name representing the DNS root (".")
+	pub fn new_root() -> Self {
+		DnsCanonicalName(DnsName::new_root())
+	}
+
+	/// Parse text representation of a domain name
+	pub fn parse(context: &DnsTextContext, value: &str) -> Result<Self>
+	{
+		Ok(DnsCanonicalName(DnsName::parse(context, value)?))
+	}
+}
+
+impl Deref for DnsCanonicalName {
+	type Target = DnsName;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl DerefMut for DnsCanonicalName {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.0
+	}
+}
+
+impl AsRef<DnsName> for DnsCanonicalName {
+	fn as_ref(&self) -> &DnsName {
+		&self.0
+	}
+}
+
+impl AsMut<DnsName> for DnsCanonicalName {
+	fn as_mut(&mut self) -> &mut DnsName {
+		&mut self.0
+	}
+}
+
+impl<'a> IntoIterator for &'a DnsCanonicalName {
+	type Item = DnsLabelRef<'a>;
+	type IntoIter = DnsNameIterator<'a>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.labels()
+	}
+}
+
+impl PartialEq<DnsName> for DnsCanonicalName
+{
+	fn eq(&self, rhs: &DnsName) -> bool {
+		let this: &DnsName = self;
+		this == rhs
+	}
+}
+
+impl<T> PartialEq<T> for DnsCanonicalName
+where
+	T: AsRef<DnsName>
+{
+	fn eq(&self, rhs: &T) -> bool {
+		let this: &DnsName = self.as_ref();
+		this == rhs
+	}
+}
+
+impl Eq for DnsCanonicalName{}
+
+impl fmt::Debug for DnsCanonicalName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		self.0.fmt(w)
+	}
+}
+
+impl fmt::Display for DnsCanonicalName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		self.0.fmt(w)
+	}
+}
+
+impl FromStr for DnsCanonicalName {
+	type Err = ::failure::Error;
+
+	fn from_str(s: &str) -> Result<Self> {
+		parse_with(s, |data| DnsCanonicalName::dns_parse(&DnsTextContext::new(), data))
+	}
+}
+
+impl DnsTextData for DnsCanonicalName {
+	fn dns_parse(context: &DnsTextContext, data: &mut &str) -> Result<Self> {
+		let field = next_field(data)?;
+		DnsCanonicalName::parse(context, field)
+	}
+
+	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
+		self.0.dns_format(f)
+	}
+}
+
+impl DnsPacketData for DnsCanonicalName {
+	fn deserialize(data: &mut Cursor<Bytes>) -> Result<Self> {
+		Ok(DnsCanonicalName(super::name_packet_parser::deserialize_name(data, false)?))
+	}
+
+	fn serialize(&self, context: &mut DnsPacketWriteContext, packet: &mut Vec<u8>) -> Result<()> {
+		context.write_canonical_name(packet, self)
+	}
+}

lib/dnsbox-base/src/common_types/name/compressed_name.rs

@@ -0,0 +1,124 @@
+use bytes::Bytes;
+use errors::*;
+use ser::packet::{DnsPacketData, DnsPacketWriteContext};
+use ser::text::{DnsTextData, DnsTextFormatter, DnsTextContext, next_field, parse_with};
+use std::fmt;
+use std::io::Cursor;
+use std::ops::{Deref, DerefMut};
+use std::str::FromStr;
+
+use super::{DnsName, DnsNameIterator, DnsLabelRef};
+
+/// Similar to `DnsName`, but allows using compressed labels in the
+/// serialized form
+#[derive(Clone)]
+pub struct DnsCompressedName(pub DnsName);
+
+impl DnsCompressedName {
+	/// Create new name representing the DNS root (".")
+	pub fn new_root() -> Self {
+		DnsCompressedName(DnsName::new_root())
+	}
+
+	/// Parse text representation of a domain name
+	pub fn parse(context: &DnsTextContext, value: &str) -> Result<Self>
+	{
+		Ok(DnsCompressedName(DnsName::parse(context, value)?))
+	}
+}
+
+impl Deref for DnsCompressedName {
+	type Target = DnsName;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl DerefMut for DnsCompressedName {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.0
+	}
+}
+
+impl AsRef<DnsName> for DnsCompressedName {
+	fn as_ref(&self) -> &DnsName {
+		&self.0
+	}
+}
+
+impl AsMut<DnsName> for DnsCompressedName {
+	fn as_mut(&mut self) -> &mut DnsName {
+		&mut self.0
+	}
+}
+
+impl<'a> IntoIterator for &'a DnsCompressedName {
+	type Item = DnsLabelRef<'a>;
+	type IntoIter = DnsNameIterator<'a>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.labels()
+	}
+}
+
+impl PartialEq<DnsName> for DnsCompressedName
+{
+	fn eq(&self, rhs: &DnsName) -> bool {
+		let this: &DnsName = self;
+		this == rhs
+	}
+}
+
+impl<T> PartialEq<T> for DnsCompressedName
+where
+	T: AsRef<DnsName>
+{
+	fn eq(&self, rhs: &T) -> bool {
+		let this: &DnsName = self.as_ref();
+		this == rhs
+	}
+}
+
+impl Eq for DnsCompressedName{}
+
+impl fmt::Debug for DnsCompressedName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		self.0.fmt(w)
+	}
+}
+
+impl fmt::Display for DnsCompressedName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		self.0.fmt(w)
+	}
+}
+
+impl FromStr for DnsCompressedName {
+	type Err = ::failure::Error;
+
+	fn from_str(s: &str) -> Result<Self> {
+		parse_with(s, |data| DnsCompressedName::dns_parse(&DnsTextContext::new(), data))
+	}
+}
+
+impl DnsTextData for DnsCompressedName {
+	fn dns_parse(context: &DnsTextContext, data: &mut &str) -> Result<Self> {
+		let field = next_field(data)?;
+		DnsCompressedName::parse(context, field)
+	}
+
+	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
+		self.0.dns_format(f)
+	}
+}
+
+impl DnsPacketData for DnsCompressedName {
+	fn deserialize(data: &mut Cursor<Bytes>) -> Result<Self> {
+		Ok(DnsCompressedName(super::name_packet_parser::deserialize_name(data, true)?))
+	}
+
+	fn serialize(&self, context: &mut DnsPacketWriteContext, packet: &mut Vec<u8>) -> Result<()> {
+		context.write_compressed_name(packet, self)
+	}
+}

lib/dnsbox-base/src/common_types/name/label_offsets.rs

@@ -0,0 +1,44 @@
+use smallvec::SmallVec;
+
+#[derive(Clone,Copy,PartialEq,Eq,PartialOrd,Ord,Hash,Debug)]
+pub enum LabelOffset {
+	LabelStart(u8),
+	PacketStart(u16),
+}
+
+// the heap meta data is usually at least 2*usize big; assuming 64-bit
+// platforms it should be ok to use 16 bytes in the smallvec.
+#[derive(Clone,PartialEq,Eq,PartialOrd,Ord,Hash,Debug)]
+pub enum LabelOffsets {
+	Uncompressed(SmallVec<[u8;16]>),
+	Compressed(usize, SmallVec<[LabelOffset;4]>),
+}
+
+impl LabelOffsets {
+	pub fn len(&self) -> u8 {
+		let l = match *self {
+			LabelOffsets::Uncompressed(ref offs) => offs.len(),
+			LabelOffsets::Compressed(_, ref offs) => offs.len(),
+		};
+		debug_assert!(l < 128);
+		l as u8
+	}
+
+	pub fn label_pos(&self, ndx: u8) -> usize {
+		debug_assert!(ndx < 127);
+		match *self {
+			LabelOffsets::Uncompressed(ref offs) => offs[ndx as usize] as usize,
+			LabelOffsets::Compressed(start, ref offs) => match offs[ndx as usize] {
+				LabelOffset::LabelStart(o) => start + (o as usize),
+				LabelOffset::PacketStart(o) => o as usize,
+			}
+		}
+	}
+
+	pub fn is_compressed(&self) -> bool {
+		match *self {
+			LabelOffsets::Uncompressed(_) => false,
+			LabelOffsets::Compressed(_, _) => true,
+		}
+	}
+}

lib/dnsbox-base/src/common_types/name/mod.rs

@@ -3,543 +3,27 @@
 
 use bytes::Bytes;
 use errors::*;
-use ser::packet::{DnsPacketData, DnsPacketWriteContext};
 use smallvec::SmallVec;
-use std::fmt;
 use std::io::Cursor;
-use std::ops::{Deref, DerefMut};
 
+pub use self::canonical_name::*;
+pub use self::compressed_name::*;
 pub use self::display::*;
 pub use self::label::*;
+pub use self::name_iterator::*;
+pub use self::name::*;
+use self::label_offsets::*;
 
+mod canonical_name;
+mod compressed_name;
 mod display;
 mod label;
+mod label_offsets;
+mod name;
+mod name_iterator;
 mod name_mutations;
 mod name_packet_parser;
 mod name_text_parser;
 
-#[derive(Clone,Copy,PartialEq,Eq,PartialOrd,Ord,Hash,Debug)]
-enum LabelOffset {
-	LabelStart(u8),
-	PacketStart(u16),
-}
-
-// the heap meta data is usually at least 2*usize big; assuming 64-bit
-// platforms it should be ok to use 16 bytes in the smallvec.
-#[derive(Clone,PartialEq,Eq,PartialOrd,Ord,Hash,Debug)]
-enum LabelOffsets {
-	Uncompressed(SmallVec<[u8;16]>),
-	Compressed(usize, SmallVec<[LabelOffset;4]>),
-}
-
-impl LabelOffsets {
-	fn len(&self) -> u8 {
-		let l = match *self {
-			LabelOffsets::Uncompressed(ref offs) => offs.len(),
-			LabelOffsets::Compressed(_, ref offs) => offs.len(),
-		};
-		debug_assert!(l < 128);
-		l as u8
-	}
-
-	fn label_pos(&self, ndx: u8) -> usize {
-		debug_assert!(ndx < 127);
-		match *self {
-			LabelOffsets::Uncompressed(ref offs) => offs[ndx as usize] as usize,
-			LabelOffsets::Compressed(start, ref offs) => match offs[ndx as usize] {
-				LabelOffset::LabelStart(o) => start + (o as usize),
-				LabelOffset::PacketStart(o) => o as usize,
-			}
-		}
-	}
-
-	fn is_compressed(&self) -> bool {
-		match *self {
-			LabelOffsets::Uncompressed(_) => false,
-			LabelOffsets::Compressed(_, _) => true,
-		}
-	}
-}
-
-/// A DNS name
-/// 
-/// Uses the "original" raw representation for storage (i.e. can share
-/// memory with a parsed packet)
-#[derive(Clone)]
-pub struct DnsName {
-	// in uncompressed form always includes terminating null octect;
-	// but even in uncompressed form can include unused bytes at the
-	// beginning
-	//
-	// may be empty for the root name (".", no labels)
-	data: Bytes,
-	// either uncompressed or compressed offsets
-	label_offsets: LabelOffsets,
-	// length of encoded form
-	total_len: u8,
-}
-
-impl DnsName {
-	/// Create new name representing the DNS root (".")
-	pub fn new_root() -> Self {
-		DnsName{
-			data: Bytes::new(),
-			label_offsets: LabelOffsets::Uncompressed(SmallVec::new()),
-			total_len: 1,
-		}
-	}
-
-	/// Create new name representing the DNS root (".") and pre-allocate
-	/// storage
-	pub fn with_capacity(labels: u8, total_len: u8) -> Self {
-		DnsName{
-			data: Bytes::with_capacity(total_len as usize),
-			label_offsets: LabelOffsets::Uncompressed(SmallVec::with_capacity(labels as usize)),
-			total_len: 1,
-		}
-	}
-
-	/// Returns whether name represents the DNS root (".")
-	pub fn is_root(&self) -> bool {
-		0 == self.label_count()
-	}
-
-	/// How many labels the name has (without the trailing empty label,
-	/// at most 127)
-	pub fn label_count(&self) -> u8 {
-		self.label_offsets.len()
-	}
-
-	/// Iterator over the labels (in the order they are stored in memory,
-	/// i.e. top-level name last).
-	pub fn labels<'a>(&'a self) -> DnsNameIterator<'a> {
-		DnsNameIterator{
-			name: &self,
-			front_label: 0,
-			back_label: self.label_offsets.len(),
-		}
-	}
-
-	/// Return label at index `ndx`
-	///
-	/// # Panics
-	///
-	/// panics if `ndx >= self.label_count()`.
-	pub fn label_ref<'a>(&'a self, ndx: u8) -> DnsLabelRef<'a> {
-		let pos = self.label_offsets.label_pos(ndx);
-		let label_len = self.data[pos];
-		debug_assert!(label_len < 64);
-		let end = pos + 1 + label_len as usize;
-		DnsLabelRef{label: &self.data[pos + 1..end]}
-	}
-
-	/// Return label at index `ndx`
-	///
-	/// # Panics
-	///
-	/// panics if `ndx >= self.label_count()`.
-	pub fn label(&self, ndx: u8) -> DnsLabel {
-		let pos = self.label_offsets.label_pos(ndx);
-		let label_len = self.data[pos];
-		debug_assert!(label_len < 64);
-		let end = pos + 1 + label_len as usize;
-		DnsLabel{label: self.data.slice(pos + 1, end) }
-	}
-}
-
-impl<'a> IntoIterator for &'a DnsName {
-	type Item = DnsLabelRef<'a>;
-	type IntoIter = DnsNameIterator<'a>;
-
-	fn into_iter(self) -> Self::IntoIter {
-		self.labels()
-	}
-}
-
-impl PartialEq<DnsName> for DnsName {
-	fn eq(&self, rhs: &DnsName) -> bool {
-		let a_labels = self.labels();
-		let b_labels = rhs.labels();
-		if a_labels.len() != b_labels.len() { return false; }
-		a_labels.zip(b_labels).all(|(a,b)| a == b)
-	}
-}
-
-impl Eq for DnsName{}
-
-impl fmt::Debug for DnsName {
-	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
-		DisplayLabels{
-			labels: self,
-			options: Default::default(),
-		}.fmt(w)
-	}
-}
-
-impl fmt::Display for DnsName {
-	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
-		DisplayLabels{
-			labels: self,
-			options: Default::default(),
-		}.fmt(w)
-	}
-}
-
-impl DnsPacketData for DnsName {
-	fn deserialize(data: &mut Cursor<Bytes>) -> Result<Self> {
-		DnsName::parse_name(data, false)
-	}
-
-	fn serialize(&self, context: &mut DnsPacketWriteContext, packet: &mut Vec<u8>) -> Result<()> {
-		context.write_uncompressed_name(packet, self)
-	}
-}
-
-/// Similar to `DnsName`, but allows using compressed labels in the
-/// serialized form
-#[derive(Clone)]
-pub struct DnsCompressedName(pub DnsName);
-
-impl DnsCompressedName {
-	/// Create new name representing the DNS root (".")
-	pub fn new_root() -> Self {
-		DnsCompressedName(DnsName::new_root())
-	}
-}
-
-impl Deref for DnsCompressedName {
-	type Target = DnsName;
-
-	fn deref(&self) -> &Self::Target {
-		&self.0
-	}
-}
-
-impl DerefMut for DnsCompressedName {
-	fn deref_mut(&mut self) -> &mut Self::Target {
-		&mut self.0
-	}
-}
-
-impl<'a> IntoIterator for &'a DnsCompressedName {
-	type Item = DnsLabelRef<'a>;
-	type IntoIter = DnsNameIterator<'a>;
-
-	fn into_iter(self) -> Self::IntoIter {
-		self.labels()
-	}
-}
-
-impl PartialEq<DnsCompressedName> for DnsCompressedName {
-	fn eq(&self, rhs: &DnsCompressedName) -> bool {
-		self.0 == rhs.0
-	}
-}
-
-impl PartialEq<DnsName> for DnsCompressedName {
-	fn eq(&self, rhs: &DnsName) -> bool {
-		&self.0 == rhs
-	}
-}
-
-impl PartialEq<DnsCompressedName> for DnsName {
-	fn eq(&self, rhs: &DnsCompressedName) -> bool {
-		self == &rhs.0
-	}
-}
-
-impl Eq for DnsCompressedName{}
-
-impl fmt::Debug for DnsCompressedName {
-	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
-		self.0.fmt(w)
-	}
-}
-
-impl fmt::Display for DnsCompressedName {
-	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
-		self.0.fmt(w)
-	}
-}
-
-impl DnsPacketData for DnsCompressedName {
-	fn deserialize(data: &mut Cursor<Bytes>) -> Result<Self> {
-		Ok(DnsCompressedName(DnsName::parse_name(data, true)?))
-	}
-
-	fn serialize(&self, context: &mut DnsPacketWriteContext, packet: &mut Vec<u8>) -> Result<()> {
-		context.write_compressed_name(packet, self)
-	}
-}
-
-/// names that should be written in canonical form for DNSSEC according
-/// to https://tools.ietf.org/html/rfc4034#section-6.2
-///
-/// TODO: make it a newtype.
-/// 
-/// DnsCompressedName always needs to be written in canonical form for
-/// DNSSEC.
-pub type DnsCanonicalName = DnsName;
-
-/// Iterator type for [`DnsName::labels`]
-///
-/// [`DnsName::labels`]: struct.DnsName.html#method.labels
-#[derive(Clone)]
-pub struct DnsNameIterator<'a> {
-	name: &'a DnsName,
-	front_label: u8,
-	back_label: u8,
-}
-
-impl<'a> Iterator for DnsNameIterator<'a> {
-	type Item = DnsLabelRef<'a>;
-
-	fn next(&mut self) -> Option<Self::Item> {
-		if self.front_label >= self.back_label { return None }
-		let label = self.name.label_ref(self.front_label);
-		self.front_label += 1;
-		Some(label)
-	}
-
-	fn size_hint(&self) -> (usize, Option<usize>) {
-		let count = self.len();
-		(count, Some(count))
-	}
-
-	fn count(self) -> usize {
-		self.len()
-	}
-}
-
-impl<'a> ExactSizeIterator for DnsNameIterator<'a> {
-	fn len(&self) -> usize {
-		(self.back_label - self.front_label) as usize
-	}
-}
-
-impl<'a> DoubleEndedIterator for DnsNameIterator<'a> {
-	fn next_back(&mut self) -> Option<Self::Item> {
-		if self.front_label >= self.back_label { return None }
-		self.back_label -= 1;
-		let label = self.name.label_ref(self.back_label);
-		Some(label)
-	}
-}
-
 #[cfg(test)]
-mod tests {
+mod tests;
-	use ser::packet;
-	use super::*;
-
-/*
-	fn deserialize(bytes: &'static [u8]) -> Result<DnsName> {
-		let result = packet::deserialize_with(Bytes::from_static(bytes), DnsName::deserialize)?;
-		{
-			let check_result = packet::deserialize_with(result.clone().encode(), DnsName::deserialize).unwrap();
-			assert_eq!(check_result, result);
-		}
-		Ok(result)
-	}
-*/
-
-	fn de_uncompressed(bytes: &'static [u8]) -> Result<DnsName> {
-		let result = packet::deserialize_with(Bytes::from_static(bytes), DnsName::deserialize)?;
-		assert_eq!(bytes, result.clone().encode());
-		Ok(result)
-	}
-
-	fn check_uncompressed_display(bytes: &'static [u8], txt: &str, label_count: u8) {
-		let name = de_uncompressed(bytes).unwrap();
-		assert_eq!(
-			name.labels().count(),
-			label_count as usize
-		);
-		assert_eq!(
-			format!("{}", name),
-			txt
-		);
-	}
-
-	fn check_uncompressed_debug(bytes: &'static [u8], txt: &str) {
-		let name = de_uncompressed(bytes).unwrap();
-		assert_eq!(
-			format!("{:?}", name),
-			txt
-		);
-	}
-
-	#[test]
-	fn parse_and_display_name() {
-		check_uncompressed_display(
-			b"\x07example\x03com\x00",
-			"example.com.",
-			2,
-		);
-		check_uncompressed_display(
-			b"\x07e!am.l\\\x03com\x00",
-			"e\\033am\\.l\\\\.com.",
-			2,
-		);
-		check_uncompressed_debug(
-			b"\x07e!am.l\\\x03com\x00",
-			r#""e\\033am\\.l\\\\.com.""#,
-		);
-	}
-
-	#[test]
-	fn parse_and_reverse_name() {
-		let name = de_uncompressed(b"\x03www\x07example\x03com\x00").unwrap();
-		assert_eq!(
-			format!(
-				"{}",
-				DisplayLabels{
-					labels: name.labels().rev(),
-					options: DisplayLabelsOptions{
-						separator: " ",
-						trailing: false,
-					},
-				}
-			),
-			"com example www"
-		);
-	}
-
-	#[test]
-	fn modifications() {
-		let mut name = de_uncompressed(b"\x07example\x03com\x00").unwrap();
-
-		name.push_front(DnsLabelRef::new(b"www").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"www.example.com."
-		);
-
-		name.push_back(DnsLabelRef::new(b"org").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"www.example.com.org."
-		);
-
-		name.pop_front();
-		assert_eq!(
-			format!("{}", name),
-			"example.com.org."
-		);
-
-		name.push_front(DnsLabelRef::new(b"mx").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"mx.example.com.org."
-		);
-		// the "mx" label should fit into the place "www" used before,
-		// make sure the buffer was reused and the name not moved within
-		assert_eq!(1, name.label_offsets.label_pos(0));
-
-		name.push_back(DnsLabelRef::new(b"com").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"mx.example.com.org.com."
-		);
-	}
-
-
-
-	fn de_compressed(bytes: &'static [u8], offset: usize) -> Result<DnsCompressedName> {
-		use bytes::Buf;
-
-		let mut c = Cursor::new(Bytes::from_static(bytes));
-		c.set_position(offset as u64);
-		let result = DnsPacketData::deserialize(&mut c)?;
-		if c.remaining() != 0 {
-			bail!("data remaining: {}", c.remaining())
-		}
-		Ok(result)
-	}
-
-	fn check_compressed_display(bytes: &'static [u8], offset: usize, txt: &str, label_count: u8) {
-		let name = de_compressed(bytes, offset).unwrap();
-		assert_eq!(
-			name.labels().count(),
-			label_count as usize
-		);
-		assert_eq!(
-			format!("{}", name),
-			txt
-		);
-	}
-
-	fn check_compressed_debug(bytes: &'static [u8], offset: usize, txt: &str) {
-		let name = de_compressed(bytes, offset).unwrap();
-		assert_eq!(
-			format!("{:?}", name),
-			txt
-		);
-	}
-
-	#[test]
-	fn parse_invalid_compressed_name() {
-		de_compressed(b"\x11com\x00\x07example\xc0\x00", 5).unwrap_err();
-		de_compressed(b"\x10com\x00\x07example\xc0\x00", 5).unwrap_err();
-	}
-
-	#[test]
-	fn parse_and_display_compressed_name() {
-		check_compressed_display(
-			b"\x03com\x00\x07example\xc0\x00", 5,
-			"example.com.",
-			2,
-		);
-		check_compressed_display(
-			b"\x03com\x00\x07e!am.l\\\xc0\x00", 5,
-			"e\\033am\\.l\\\\.com.",
-			2,
-		);
-		check_compressed_debug(
-			b"\x03com\x00\x07e!am.l\\\xc0\x00", 5,
-			r#""e\\033am\\.l\\\\.com.""#,
-		);
-		check_compressed_display(
-			b"\x03com\x00\x07example\xc0\x00\x03www\xc0\x05", 15,
-			"www.example.com.",
-			3,
-		);
-	}
-
-	#[test]
-	fn modifications_compressed() {
-		let mut name = de_compressed(b"\x03com\x00\x07example\xc0\x00\xc0\x05", 15).unwrap();
-
-		name.push_front(DnsLabelRef::new(b"www").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"www.example.com."
-		);
-
-		name.push_back(DnsLabelRef::new(b"org").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"www.example.com.org."
-		);
-
-		name.pop_front();
-		assert_eq!(
-			format!("{}", name),
-			"example.com.org."
-		);
-
-		name.push_front(DnsLabelRef::new(b"mx").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"mx.example.com.org."
-		);
-		// the "mx" label should fit into the place "www" used before,
-		// make sure the buffer was reused and the name not moved within
-		assert_eq!(1, name.label_offsets.label_pos(0));
-
-		name.push_back(DnsLabelRef::new(b"com").unwrap()).unwrap();
-		assert_eq!(
-			format!("{}", name),
-			"mx.example.com.org.com."
-		);
-	}
-}

lib/dnsbox-base/src/common_types/name/name.rs

@@ -0,0 +1,178 @@
+use bytes::Bytes;
+use errors::*;
+use ser::packet::{DnsPacketData, DnsPacketWriteContext};
+use ser::text::{DnsTextData, DnsTextFormatter, DnsTextContext, next_field, parse_with};
+use smallvec::SmallVec;
+use std::fmt;
+use std::io::Cursor;
+use std::str::FromStr;
+
+use super::{LabelOffsets, DnsNameIterator, DnsLabelRef, DnsLabel, DisplayLabels};
+
+/// A DNS name
+/// 
+/// Uses the "original" raw representation for storage (i.e. can share
+/// memory with a parsed packet)
+#[derive(Clone)]
+pub struct DnsName {
+	// in uncompressed form always includes terminating null octect;
+	// but even in uncompressed form can include unused bytes at the
+	// beginning
+	//
+	// may be empty for the root name (".", no labels)
+	pub(super) data: Bytes,
+	// either uncompressed or compressed offsets
+	pub(super) label_offsets: LabelOffsets,
+	// length of encoded form
+	pub(super) total_len: u8,
+}
+
+impl DnsName {
+	/// Create new name representing the DNS root (".")
+	pub fn new_root() -> Self {
+		DnsName{
+			data: Bytes::new(),
+			label_offsets: LabelOffsets::Uncompressed(SmallVec::new()),
+			total_len: 1,
+		}
+	}
+
+	/// Create new name representing the DNS root (".") and pre-allocate
+	/// storage
+	pub fn with_capacity(labels: u8, total_len: u8) -> Self {
+		DnsName{
+			data: Bytes::with_capacity(total_len as usize),
+			label_offsets: LabelOffsets::Uncompressed(SmallVec::with_capacity(labels as usize)),
+			total_len: 1,
+		}
+	}
+
+	/// Parse text representation of a domain name
+	pub fn parse(context: &DnsTextContext, value: &str) -> Result<Self> {
+		super::name_text_parser::parse_name(context, value)
+	}
+
+	/// Returns whether name represents the DNS root (".")
+	pub fn is_root(&self) -> bool {
+		0 == self.label_count()
+	}
+
+	/// How many labels the name has (without the trailing empty label,
+	/// at most 127)
+	pub fn label_count(&self) -> u8 {
+		self.label_offsets.len()
+	}
+
+	/// Iterator over the labels (in the order they are stored in memory,
+	/// i.e. top-level name last).
+	pub fn labels<'a>(&'a self) -> DnsNameIterator<'a> {
+		DnsNameIterator{
+			name: &self,
+			front_label: 0,
+			back_label: self.label_offsets.len(),
+		}
+	}
+
+	/// Return label at index `ndx`
+	///
+	/// # Panics
+	///
+	/// panics if `ndx >= self.label_count()`.
+	pub fn label_ref<'a>(&'a self, ndx: u8) -> DnsLabelRef<'a> {
+		let pos = self.label_offsets.label_pos(ndx);
+		let label_len = self.data[pos];
+		debug_assert!(label_len < 64);
+		let end = pos + 1 + label_len as usize;
+		DnsLabelRef{label: &self.data[pos + 1..end]}
+	}
+
+	/// Return label at index `ndx`
+	///
+	/// # Panics
+	///
+	/// panics if `ndx >= self.label_count()`.
+	pub fn label(&self, ndx: u8) -> DnsLabel {
+		let pos = self.label_offsets.label_pos(ndx);
+		let label_len = self.data[pos];
+		debug_assert!(label_len < 64);
+		let end = pos + 1 + label_len as usize;
+		DnsLabel{label: self.data.slice(pos + 1, end) }
+	}
+}
+
+impl<'a> IntoIterator for &'a DnsName {
+	type Item = DnsLabelRef<'a>;
+	type IntoIter = DnsNameIterator<'a>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.labels()
+	}
+}
+
+impl PartialEq<DnsName> for DnsName
+{
+	fn eq(&self, rhs: &DnsName) -> bool {
+		let a_labels = self.labels();
+		let b_labels = rhs.labels();
+		if a_labels.len() != b_labels.len() { return false; }
+		a_labels.zip(b_labels).all(|(a,b)| a == b)
+	}
+}
+
+impl<T> PartialEq<T> for DnsName
+where
+	T: AsRef<DnsName>
+{
+	fn eq(&self, rhs: &T) -> bool {
+		self == rhs.as_ref()
+	}
+}
+
+impl Eq for DnsName{}
+
+impl fmt::Debug for DnsName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		DisplayLabels{
+			labels: self,
+			options: Default::default(),
+		}.fmt(w)
+	}
+}
+
+impl fmt::Display for DnsName {
+	fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+		DisplayLabels{
+			labels: self,
+			options: Default::default(),
+		}.fmt(w)
+	}
+}
+
+impl FromStr for DnsName {
+	type Err = ::failure::Error;
+
+	fn from_str(s: &str) -> Result<Self> {
+		parse_with(s, |data| DnsName::dns_parse(&DnsTextContext::new(), data))
+	}
+}
+
+impl DnsTextData for DnsName {
+	fn dns_parse(context: &DnsTextContext, data: &mut &str) -> Result<Self> {
+		let field = next_field(data)?;
+		DnsName::parse(context, field)
+	}
+
+	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
+		write!(f, "{}", self)
+	}
+}
+
+impl DnsPacketData for DnsName {
+	fn deserialize(data: &mut Cursor<Bytes>) -> Result<Self> {
+		super::name_packet_parser::deserialize_name(data, false)
+	}
+
+	fn serialize(&self, context: &mut DnsPacketWriteContext, packet: &mut Vec<u8>) -> Result<()> {
+		context.write_uncompressed_name(packet, self)
+	}
+}

lib/dnsbox-base/src/common_types/name/name_iterator.rs

@@ -0,0 +1,46 @@
+use super::{DnsName, DnsLabelRef};
+
+/// Iterator type for [`DnsName::labels`]
+///
+/// [`DnsName::labels`]: struct.DnsName.html#method.labels
+#[derive(Clone)]
+pub struct DnsNameIterator<'a> {
+	pub(super) name: &'a DnsName,
+	pub(super) front_label: u8,
+	pub(super) back_label: u8,
+}
+
+impl<'a> Iterator for DnsNameIterator<'a> {
+	type Item = DnsLabelRef<'a>;
+
+	fn next(&mut self) -> Option<Self::Item> {
+		if self.front_label >= self.back_label { return None }
+		let label = self.name.label_ref(self.front_label);
+		self.front_label += 1;
+		Some(label)
+	}
+
+	fn size_hint(&self) -> (usize, Option<usize>) {
+		let count = self.len();
+		(count, Some(count))
+	}
+
+	fn count(self) -> usize {
+		self.len()
+	}
+}
+
+impl<'a> ExactSizeIterator for DnsNameIterator<'a> {
+	fn len(&self) -> usize {
+		(self.back_label - self.front_label) as usize
+	}
+}
+
+impl<'a> DoubleEndedIterator for DnsNameIterator<'a> {
+	fn next_back(&mut self) -> Option<Self::Item> {
+		if self.front_label >= self.back_label { return None }
+		self.back_label -= 1;
+		let label = self.name.label_ref(self.back_label);
+		Some(label)
+	}
+}

lib/dnsbox-base/src/common_types/name/name_packet_parser.rs

@@ -1,13 +1,12 @@
 use bytes::Buf;
 use super::*;
 
-impl DnsName {
+/// `data`: bytes of packet from beginning until at least the end of the name
-	/// `data`: bytes of packet from beginning until at least the end of the name
+/// `start_pos`: position of first byte of the name
-	/// `start_pos`: position of first byte of the name
+/// `uncmpr_offsets`: offsets of uncompressed labels so far
-	/// `uncmpr_offsets`: offsets of uncompressed labels so far
+/// `label_len`: first compressed  label length (`0xc0 | offset-high, offset-low`)
-	/// `label_len`: first compressed  label length (`0xc0 | offset-high, offset-low`)
+/// `total_len`: length of (uncompressed) label encoding so far
-	/// `total_len`: length of (uncompressed) label encoding so far
+fn deserialize_name_compressed_cont(data: Bytes, start_pos: usize, uncmpr_offsets: SmallVec<[u8;16]>, mut total_len: usize, mut label_len: u8) -> Result<DnsName> {
-	fn parse_name_compressed_cont(data: Bytes, start_pos: usize, uncmpr_offsets: SmallVec<[u8;16]>, mut total_len: usize, mut label_len: u8) -> Result<Self> {
 	let mut label_offsets = uncmpr_offsets.into_iter()
 	.map(LabelOffset::LabelStart)
 	.collect::<SmallVec<_>>();
@@ -44,9 +43,9 @@ impl DnsName {
 			pos += 1 + label_len as usize;
 		}
 	}
-	}
+}
 
-	pub(super) fn parse_name(data: &mut Cursor<Bytes>, accept_compressed: bool) -> Result<Self> {
+pub fn deserialize_name(data: &mut Cursor<Bytes>, accept_compressed: bool) -> Result<DnsName> {
 	check_enough_data!(data, 1, "DnsName");
 	let start_pos = data.position() as usize;
 	let mut total_len : usize = 0;
@@ -72,7 +71,7 @@ impl DnsName {
 			let end_pos = data.position() as usize;
 			let data = data.get_ref().slice(0, end_pos);
 
-				return Self::parse_name_compressed_cont(data, start_pos, label_offsets, total_len, label_len as u8);
+			return deserialize_name_compressed_cont(data, start_pos, label_offsets, total_len, label_len as u8);
 		}
 		label_offsets.push(total_len as u8);
 		if label_len > 63 { bail!("Invalid label length {}", label_len) }
@@ -82,5 +81,4 @@ impl DnsName {
 		check_enough_data!(data, (label_len), "DnsName label");
 		data.advance(label_len);
 	}
-	}
 }

lib/dnsbox-base/src/common_types/name/name_text_parser.rs

@@ -1,10 +1,11 @@
-use super::*;
+use errors::*;
-use ser::text::{DnsTextData, DnsTextFormatter, DnsTextContext, next_field, quoted, parse_with};
+use ser::text::{DnsTextContext, quoted};
 
-impl DnsName {
+use super::{DnsName, DnsLabelRef};
-	/// Parse text representation of a domain name
+
-	pub fn parse(context: &DnsTextContext, value: &str) -> Result<Self>
+/// Parse text representation of a domain name
-	{
+pub fn parse_name(context: &DnsTextContext, value: &str) -> Result<DnsName>
+{
 	let raw = value.as_bytes();
 	let mut name = DnsName::new_root();
 	if raw == b"." {
@@ -61,51 +62,4 @@ impl DnsName {
 	}
 
 	Ok(name)
-	}
-}
-
-impl DnsTextData for DnsName {
-	fn dns_parse(context: &DnsTextContext, data: &mut &str) -> Result<Self> {
-		let field = next_field(data)?;
-		DnsName::parse(context, field)
-	}
-
-	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
-		write!(f, "{}", self)
-	}
-}
-
-impl ::std::str::FromStr for DnsName {
-	type Err = ::failure::Error;
-
-	fn from_str(s: &str) -> Result<Self> {
-		parse_with(s, |data| DnsName::dns_parse(&DnsTextContext::new(), data))
-	}
-}
-
-impl DnsCompressedName {
-	/// Parse text representation of a domain name
-	pub fn parse(context: &DnsTextContext, value: &str) -> Result<Self>
-	{
-		Ok(DnsCompressedName(DnsName::parse(context, value)?))
-	}
-}
-
-impl DnsTextData for DnsCompressedName {
-	fn dns_parse(context: &DnsTextContext, data: &mut &str) -> Result<Self> {
-		let field = next_field(data)?;
-		DnsCompressedName::parse(context, field)
-	}
-
-	fn dns_format(&self, f: &mut DnsTextFormatter) -> fmt::Result {
-		self.0.dns_format(f)
-	}
-}
-
-impl ::std::str::FromStr for DnsCompressedName {
-	type Err = ::failure::Error;
-
-	fn from_str(s: &str) -> Result<Self> {
-		parse_with(s, |data| DnsCompressedName::dns_parse(&DnsTextContext::new(), data))
-	}
 }

lib/dnsbox-base/src/common_types/name/tests.rs

@@ -0,0 +1,219 @@
+use bytes::Bytes;
+use ser::packet;
+use ser::packet::DnsPacketData;
+use std::io::Cursor;
+use errors::*;
+
+use super::{DnsName, DnsCompressedName, DnsLabelRef, DisplayLabels, DisplayLabelsOptions};
+
+/*
+fn deserialize(bytes: &'static [u8]) -> Result<DnsName> {
+	let result = packet::deserialize_with(Bytes::from_static(bytes), DnsName::deserialize)?;
+	{
+		let check_result = packet::deserialize_with(result.clone().encode(), DnsName::deserialize).unwrap();
+		assert_eq!(check_result, result);
+	}
+	Ok(result)
+}
+*/
+
+fn de_uncompressed(bytes: &'static [u8]) -> Result<DnsName> {
+	let result = packet::deserialize_with(Bytes::from_static(bytes), DnsName::deserialize)?;
+	assert_eq!(bytes, result.clone().encode());
+	Ok(result)
+}
+
+fn check_uncompressed_display(bytes: &'static [u8], txt: &str, label_count: u8) {
+	let name = de_uncompressed(bytes).unwrap();
+	assert_eq!(
+		name.labels().count(),
+		label_count as usize
+	);
+	assert_eq!(
+		format!("{}", name),
+		txt
+	);
+}
+
+fn check_uncompressed_debug(bytes: &'static [u8], txt: &str) {
+	let name = de_uncompressed(bytes).unwrap();
+	assert_eq!(
+		format!("{:?}", name),
+		txt
+	);
+}
+
+#[test]
+fn parse_and_display_name() {
+	check_uncompressed_display(
+		b"\x07example\x03com\x00",
+		"example.com.",
+		2,
+	);
+	check_uncompressed_display(
+		b"\x07e!am.l\\\x03com\x00",
+		"e\\033am\\.l\\\\.com.",
+		2,
+	);
+	check_uncompressed_debug(
+		b"\x07e!am.l\\\x03com\x00",
+		r#""e\\033am\\.l\\\\.com.""#,
+	);
+}
+
+#[test]
+fn parse_and_reverse_name() {
+	let name = de_uncompressed(b"\x03www\x07example\x03com\x00").unwrap();
+	assert_eq!(
+		format!(
+			"{}",
+			DisplayLabels{
+				labels: name.labels().rev(),
+				options: DisplayLabelsOptions{
+					separator: " ",
+					trailing: false,
+				},
+			}
+		),
+		"com example www"
+	);
+}
+
+#[test]
+fn modifications() {
+	let mut name = de_uncompressed(b"\x07example\x03com\x00").unwrap();
+
+	name.push_front(DnsLabelRef::new(b"www").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"www.example.com."
+	);
+
+	name.push_back(DnsLabelRef::new(b"org").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"www.example.com.org."
+	);
+
+	name.pop_front();
+	assert_eq!(
+		format!("{}", name),
+		"example.com.org."
+	);
+
+	name.push_front(DnsLabelRef::new(b"mx").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"mx.example.com.org."
+	);
+	// the "mx" label should fit into the place "www" used before,
+	// make sure the buffer was reused and the name not moved within
+	assert_eq!(1, name.label_offsets.label_pos(0));
+
+	name.push_back(DnsLabelRef::new(b"com").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"mx.example.com.org.com."
+	);
+}
+
+
+
+fn de_compressed(bytes: &'static [u8], offset: usize) -> Result<DnsCompressedName> {
+	use bytes::Buf;
+
+	let mut c = Cursor::new(Bytes::from_static(bytes));
+	c.set_position(offset as u64);
+	let result = DnsPacketData::deserialize(&mut c)?;
+	if c.remaining() != 0 {
+		bail!("data remaining: {}", c.remaining())
+	}
+	Ok(result)
+}
+
+fn check_compressed_display(bytes: &'static [u8], offset: usize, txt: &str, label_count: u8) {
+	let name = de_compressed(bytes, offset).unwrap();
+	assert_eq!(
+		name.labels().count(),
+		label_count as usize
+	);
+	assert_eq!(
+		format!("{}", name),
+		txt
+	);
+}
+
+fn check_compressed_debug(bytes: &'static [u8], offset: usize, txt: &str) {
+	let name = de_compressed(bytes, offset).unwrap();
+	assert_eq!(
+		format!("{:?}", name),
+		txt
+	);
+}
+
+#[test]
+fn parse_invalid_compressed_name() {
+	de_compressed(b"\x11com\x00\x07example\xc0\x00", 5).unwrap_err();
+	de_compressed(b"\x10com\x00\x07example\xc0\x00", 5).unwrap_err();
+}
+
+#[test]
+fn parse_and_display_compressed_name() {
+	check_compressed_display(
+		b"\x03com\x00\x07example\xc0\x00", 5,
+		"example.com.",
+		2,
+	);
+	check_compressed_display(
+		b"\x03com\x00\x07e!am.l\\\xc0\x00", 5,
+		"e\\033am\\.l\\\\.com.",
+		2,
+	);
+	check_compressed_debug(
+		b"\x03com\x00\x07e!am.l\\\xc0\x00", 5,
+		r#""e\\033am\\.l\\\\.com.""#,
+	);
+	check_compressed_display(
+		b"\x03com\x00\x07example\xc0\x00\x03www\xc0\x05", 15,
+		"www.example.com.",
+		3,
+	);
+}
+
+#[test]
+fn modifications_compressed() {
+	let mut name = de_compressed(b"\x03com\x00\x07example\xc0\x00\xc0\x05", 15).unwrap();
+
+	name.push_front(DnsLabelRef::new(b"www").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"www.example.com."
+	);
+
+	name.push_back(DnsLabelRef::new(b"org").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"www.example.com.org."
+	);
+
+	name.pop_front();
+	assert_eq!(
+		format!("{}", name),
+		"example.com.org."
+	);
+
+	name.push_front(DnsLabelRef::new(b"mx").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"mx.example.com.org."
+	);
+	// the "mx" label should fit into the place "www" used before,
+	// make sure the buffer was reused and the name not moved within
+	assert_eq!(1, name.label_offsets.label_pos(0));
+
+	name.push_back(DnsLabelRef::new(b"com").unwrap()).unwrap();
+	assert_eq!(
+		format!("{}", name),
+		"mx.example.com.org.com."
+	);
+}

lib/dnsbox-base/src/common_types/types.rs

@@ -474,7 +474,6 @@ impl Type {
 
 	/// parses generic names of the form "TYPE..."
 	pub fn from_generic_name(name: &str) -> Option<Self> {
-		use std::ascii::AsciiExt;
 		if name.len() > 4 && name.as_bytes()[0..4].eq_ignore_ascii_case(b"TYPE") {
 			name[4..].parse::<u16>().ok().map(Type)
 		} else {

lib/dnsbox-base/src/records/registry.rs

@@ -1,6 +1,5 @@
 use bytes::Bytes;
 use std::any::TypeId;
-use std::ascii::AsciiExt;
 use std::collections::HashMap;
 use std::io::Cursor;
 use std::marker::PhantomData;

lib/dnsbox-base/src/ser/packet/write.rs

@@ -68,6 +68,24 @@ fn write_name(packet: &mut Vec<u8>, name: &DnsName) {
 	packet.put_u8(0);
 }
 
+fn write_canonical_label(packet: &mut Vec<u8>, label: DnsLabelRef) {
+	let l = label.len();
+	debug_assert!(l < 64);
+	packet.reserve(l as usize + 1);
+	packet.put_u8(l);
+	for c in label.as_raw() {
+		packet.put_u8(c.to_ascii_lowercase());
+	}
+}
+
+fn write_canonical_name(packet: &mut Vec<u8>, name: &DnsName) {
+	for label in name {
+		write_canonical_label(packet, label);
+	}
+	packet.reserve(1);
+	packet.put_u8(0);
+}
+
 fn write_label_remember(packet: &mut Vec<u8>, labels: &mut Vec<LabelEntry>, label: DnsLabelRef, next_entry: usize) {
 	labels.push(LabelEntry {
 		pos: packet.len(),
@@ -76,9 +94,23 @@ fn write_label_remember(packet: &mut Vec<u8>, labels: &mut Vec<LabelEntry>, labe
 	write_label(packet, label);
 }
 
+#[derive(Clone, Debug)]
+enum LabelWriteMethod {
+	Uncompressed,
+	Compressed(Vec<LabelEntry>),
+	Canonical, // DNSSEC, uncompressed + ASCII lower-case
+}
+
+impl Default for LabelWriteMethod {
+	fn default() -> Self {
+		LabelWriteMethod::Uncompressed
+	}
+}
+
 #[derive(Clone, Debug, Default)]
 pub struct DnsPacketWriteContext {
-	labels: Option<Vec<LabelEntry>>,
+	labels: LabelWriteMethod,
+
 }
 
 impl DnsPacketWriteContext {
@@ -86,11 +118,26 @@ impl DnsPacketWriteContext {
 		Default::default()
 	}
 
+	/// Enables writing compressed names
+	///
+	/// Only `DnsCompressedName` uses compression, `DnsName` and
+	/// `DnsCanonicalName` are never compressed.
 	pub fn enable_compression(&mut self) {
-		self.labels = Some(Vec::new());
+		self.labels = LabelWriteMethod::Compressed(Vec::new());
 	}
 
-	pub fn write_uncompressed_name(&mut self, packet: &mut Vec<u8>, name: &DnsName) -> Result<()> {
+	/// Enables writing canonical names
+	///
+	/// Disables compression, and converts `DnsCompressedName` and
+	/// `DnsCanonicalName` to ASCII lowercase.
+	///
+	/// `DnsName` is never compressed, but also never converted to
+	/// lowercase.
+	pub fn enable_canonical(&mut self) {
+		self.labels = LabelWriteMethod::Canonical;
+	}
+
+	pub(crate) fn write_uncompressed_name(&mut self, packet: &mut Vec<u8>, name: &DnsName) -> Result<()> {
 		// for now we don't remember labels of these names.
 		//
 		// if we did: would we want to check whether a suffix is already
@@ -100,19 +147,36 @@ impl DnsPacketWriteContext {
 		Ok(())
 	}
 
-	pub fn write_compressed_name(&mut self, packet: &mut Vec<u8>, name: &DnsCompressedName) -> Result<()> {
+	pub(crate) fn write_canonical_name(&mut self, packet: &mut Vec<u8>, name: &DnsName) -> Result<()> {
+		match self.labels {
+			LabelWriteMethod::Uncompressed | LabelWriteMethod::Compressed(_) => {
+				// uncompressed
+				write_name(packet, name);
+			},
+			LabelWriteMethod::Canonical => {
+				write_canonical_name(packet, name);
+			},
+		}
+		return Ok(())
+	}
+
+	pub(crate) fn write_compressed_name(&mut self, packet: &mut Vec<u8>, name: &DnsCompressedName) -> Result<()> {
+		// for DNSSEC we need to write it canonical
 		if name.is_root() {
 			write_name(packet, name);
 			return Ok(());
 		}
 
 		let labels = match self.labels {
-			Some(ref mut labels) => labels,
+			LabelWriteMethod::Uncompressed => {
-			None => {
-				// compression disabled
 				write_name(packet, name);
 				return Ok(());
-			}
+			},
+			LabelWriteMethod::Compressed(ref mut labels) => labels,
+			LabelWriteMethod::Canonical => {
+				write_canonical_name(packet, name);
+				return Ok(())
+			},
 		};
 
 		let mut best_match = None;