From 7bc4ffd0a40b212224d80dd8b0d1ca5239979e80 Mon Sep 17 00:00:00 2001
From: Brian Smith <brian@briansmith.org>
Date: Thu, 5 Apr 2018 16:49:32 -1000
Subject: [PATCH] Revert "Proxy: Refactor DNS name parsing and normalization
 (#673)" (#700)

This reverts commit 311ef410a8baf513153e060ec0f60d9e803af28e.

Signed-off-by: Brian Smith <brian@briansmith.org>
---
 proxy/src/config.rs                    |   4 +-
 proxy/src/control/discovery.rs         |  83 +++++---------
 proxy/src/control/mod.rs               |  10 +-
 proxy/src/dns.rs                       |  91 ++-------------
 proxy/src/fully_qualified_authority.rs | 150 ++++++++++++++++---------
 proxy/src/lib.rs                       |   5 +-
 proxy/src/outbound.rs                  | 107 +++++++++---------
 proxy/src/transport/connect.rs         |  35 ++----
 proxy/src/transport/mod.rs             |   2 +-
 9 files changed, 207 insertions(+), 280 deletions(-)

diff --git a/proxy/src/config.rs b/proxy/src/config.rs
index 2ccdd5607..d79bbf746 100644
--- a/proxy/src/config.rs
+++ b/proxy/src/config.rs
@@ -349,7 +349,7 @@ fn parse_url(s: &str) -> Result<HostAndPort, ParseError> {
     // https://github.com/hyperium/http/issues/127. For now just ignore any
     // fragment that is there.
 
-    HostAndPort::normalize(authority, None)
+    HostAndPort::try_from(authority)
         .map_err(|e| ParseError::UrlError(UrlError::AuthorityError(e)))
 }
 
@@ -366,7 +366,7 @@ fn parse<T, Parse>(strings: &Strings, name: &str, parse: Parse) -> Result<Option
     match strings.get(name)? {
         Some(ref s) => {
             let r = parse(s).map_err(|parse_error| {
-                error!("{}={:?} is not valid: {:?}", name, s, parse_error);
+                error!("{} is not valid: {:?}", name, parse_error);
                 Error::InvalidEnvVar
             })?;
             Ok(Some(r))
diff --git a/proxy/src/control/discovery.rs b/proxy/src/control/discovery.rs
index 8af0df5d6..85ffd179f 100644
--- a/proxy/src/control/discovery.rs
+++ b/proxy/src/control/discovery.rs
@@ -16,14 +16,13 @@ use conduit_proxy_controller_grpc::common::{Destination, TcpAddress};
 use conduit_proxy_controller_grpc::destination::Update as PbUpdate;
 use conduit_proxy_controller_grpc::destination::update::Update as PbUpdate2;
 use conduit_proxy_controller_grpc::destination::client::{Destination as DestinationSvc};
-use transport::DnsNameAndPort;
 
 use control::cache::{Cache, CacheChange, Exists};
 
 /// A handle to start watching a destination for address changes.
 #[derive(Clone, Debug)]
 pub struct Discovery {
-    tx: mpsc::UnboundedSender<(DnsNameAndPort, mpsc::UnboundedSender<Update>)>,
+    tx: mpsc::UnboundedSender<(FullyQualifiedAuthority, mpsc::UnboundedSender<Update>)>,
 }
 
 /// A `tower_discover::Discover`, given to a `tower_balance::Balance`.
@@ -36,28 +35,29 @@ pub struct Watch<B> {
 /// A background handle to eventually bind on the controller thread.
 #[derive(Debug)]
 pub struct Background {
-    rx: mpsc::UnboundedReceiver<(DnsNameAndPort, mpsc::UnboundedSender<Update>)>,
-    default_destination_namespace: String,
+    rx: mpsc::UnboundedReceiver<(FullyQualifiedAuthority, mpsc::UnboundedSender<Update>)>,
 }
 
 /// A future returned from `Background::work()`, doing the work of talking to
 /// the controller destination API.
 // TODO: debug impl
 pub struct DiscoveryWork<T: HttpService<ResponseBody = RecvBody>> {
-    default_destination_namespace: String,
-    destinations: HashMap<DnsNameAndPort, DestinationSet<T>>,
+    destinations: HashMap<
+        FullyQualifiedAuthority,
+        DestinationSet<T>
+    >,
     /// A queue of authorities that need to be reconnected.
-    reconnects: VecDeque<DnsNameAndPort>,
+    reconnects: VecDeque<FullyQualifiedAuthority>,
     /// The Destination.Get RPC client service.
     /// Each poll, records whether the rpc service was till ready.
     rpc_ready: bool,
     /// A receiver of new watch requests.
-    rx: mpsc::UnboundedReceiver<(DnsNameAndPort, mpsc::UnboundedSender<Update>)>,
+    rx: mpsc::UnboundedReceiver<(FullyQualifiedAuthority, mpsc::UnboundedSender<Update>)>,
 }
 
 struct DestinationSet<T: HttpService<ResponseBody = RecvBody>> {
     addrs: Exists<Cache<SocketAddr>>,
-    query: Option<DestinationServiceQuery<T>>,
+    query: DestinationServiceQuery<T>,
     txs: Vec<mpsc::UnboundedSender<Update>>,
 }
 
@@ -129,7 +129,7 @@ pub trait Bind {
 ///
 /// The `Discovery` is used by a listener, the `Background` is consumed
 /// on the controller thread.
-pub fn new(default_destination_namespace: String) -> (Discovery, Background) {
+pub fn new() -> (Discovery, Background) {
     let (tx, rx) = mpsc::unbounded();
     (
         Discovery {
@@ -137,7 +137,6 @@ pub fn new(default_destination_namespace: String) -> (Discovery, Background) {
         },
         Background {
             rx,
-            default_destination_namespace,
         },
     )
 }
@@ -146,7 +145,7 @@ pub fn new(default_destination_namespace: String) -> (Discovery, Background) {
 
 impl Discovery {
     /// Start watching for address changes for a certain authority.
-    pub fn resolve<B>(&self, authority: &DnsNameAndPort, bind: B) -> Watch<B> {
+    pub fn resolve<B>(&self, authority: &FullyQualifiedAuthority, bind: B) -> Watch<B> {
         trace!("resolve; authority={:?}", authority);
         let (tx, rx) = mpsc::unbounded();
         self.tx
@@ -203,7 +202,6 @@ impl Background {
           T::Error: fmt::Debug,
     {
         DiscoveryWork {
-            default_destination_namespace: self.default_destination_namespace,
             destinations: HashMap::new(),
             reconnects: VecDeque::new(),
             rpc_ready: false,
@@ -278,11 +276,7 @@ where
                         }
                         Entry::Vacant(vac) => {
                             let query =
-                                DestinationServiceQuery::connect_maybe(
-                                    &self.default_destination_namespace,
-                                    client,
-                                    vac.key(),
-                                    "connect");
+                                DestinationServiceQuery::connect(client, vac.key(), "connect");
                             vac.insert(DestinationSet {
                                 addrs: Exists::Unknown,
                                 query,
@@ -307,11 +301,7 @@ where
 
         while let Some(auth) = self.reconnects.pop_front() {
             if let Some(set) = self.destinations.get_mut(&auth) {
-                set.query = DestinationServiceQuery::connect_maybe(
-                    &self.default_destination_namespace,
-                    client,
-                    &auth,
-                    "reconnect");
+                set.query = DestinationServiceQuery::connect(client, &auth, "reconnect");
                 return true;
             } else {
                 trace!("reconnect no longer needed: {:?}", auth);
@@ -324,11 +314,10 @@ where
         for (auth, set) in &mut self.destinations {
             let needs_reconnect = 'set: loop {
                 let poll_result = match set.query {
-                    None |
-                    Some(DestinationServiceQuery::NeedsReconnect) => {
+                    DestinationServiceQuery::NeedsReconnect => {
                         continue;
                     },
-                    Some(DestinationServiceQuery::ConnectedOrConnecting{ ref mut rx }) => {
+                    DestinationServiceQuery::ConnectedOrConnecting{ ref mut rx } => {
                         rx.poll()
                     }
                 };
@@ -364,9 +353,9 @@ where
 
             };
             if needs_reconnect {
-                set.query = Some(DestinationServiceQuery::NeedsReconnect);
+                set.query = DestinationServiceQuery::NeedsReconnect;
                 set.reset_on_next_modification();
-                self.reconnects.push_back(auth.clone());
+                self.reconnects.push_back(FullyQualifiedAuthority::clone(auth));
             }
         }
     }
@@ -376,28 +365,16 @@ where
 // ===== impl DestinationServiceQuery =====
 
 impl<T: HttpService<RequestBody = BoxBody, ResponseBody = RecvBody>> DestinationServiceQuery<T> {
-    // Initiates a query `query` to the Destination service and returns it as `Some(query)` if the
-    // given authority's host is of a form suitable for using to query the Destination service.
-    // Otherwise, returns `None`.
-    fn connect_maybe(
-        default_destination_namespace: &str,
-        client: &mut T,
-        auth: &DnsNameAndPort,
-        connect_or_reconnect: &str)
-        -> Option<Self>
-    {
+    fn connect(client: &mut T, auth: &FullyQualifiedAuthority, connect_or_reconnect: &str) -> Self {
         trace!("DestinationServiceQuery {} {:?}", connect_or_reconnect, auth);
-        FullyQualifiedAuthority::normalize(auth, default_destination_namespace)
-            .map(|auth| {
-                let req = Destination {
-                    scheme: "k8s".into(),
-                    path: auth.without_trailing_dot().to_owned(),
-                };
-                // TODO: Can grpc::Request::new be removed?
-                let mut svc = DestinationSvc::new(client.lift_ref());
-                let response = svc.get(grpc::Request::new(req));
-                DestinationServiceQuery::ConnectedOrConnecting { rx: UpdateRx::Waiting(response) }
-            })
+        let req = Destination {
+            scheme: "k8s".into(),
+            path: auth.without_trailing_dot().as_str().into(),
+        };
+        // TODO: Can grpc::Request::new be removed?
+        let mut svc = DestinationSvc::new(client.lift_ref());
+        let response = svc.get(grpc::Request::new(req));
+        DestinationServiceQuery::ConnectedOrConnecting { rx: UpdateRx::Waiting(response) }
     }
 }
 
@@ -414,7 +391,7 @@ impl <T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
         }
     }
 
-    fn add<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_add: A)
+    fn add<A>(&mut self, authority_for_logging: &FullyQualifiedAuthority, addrs_to_add: A)
         where A: Iterator<Item = SocketAddr>
     {
         let mut cache = match self.addrs.take() {
@@ -428,7 +405,7 @@ impl <T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
         self.addrs = Exists::Yes(cache);
     }
 
-    fn remove<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_remove: A)
+    fn remove<A>(&mut self, authority_for_logging: &FullyQualifiedAuthority, addrs_to_remove: A)
         where A: Iterator<Item = SocketAddr>
     {
         let cache = match self.addrs.take() {
@@ -444,7 +421,7 @@ impl <T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
         self.addrs = Exists::Yes(cache);
     }
 
-    fn no_endpoints(&mut self, authority_for_logging: &DnsNameAndPort, exists: bool) {
+    fn no_endpoints(&mut self, authority_for_logging: &FullyQualifiedAuthority, exists: bool) {
         trace!("no endpoints for {:?} that is known to {}", authority_for_logging,
                if exists { "exist" } else { "not exist" });
         match self.addrs.take() {
@@ -463,7 +440,7 @@ impl <T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
     }
 
     fn on_change(txs: &mut Vec<mpsc::UnboundedSender<Update>>,
-                 authority_for_logging: &DnsNameAndPort,
+                 authority_for_logging: &FullyQualifiedAuthority,
                  addr: SocketAddr,
                  change: CacheChange) {
         let (update_str, update_constructor): (&'static str, fn(SocketAddr) -> Update) =
diff --git a/proxy/src/control/mod.rs b/proxy/src/control/mod.rs
index 630b07a18..5095206f6 100644
--- a/proxy/src/control/mod.rs
+++ b/proxy/src/control/mod.rs
@@ -17,7 +17,8 @@ use tower_h2;
 use tower_reconnect::{Error as ReconnectError, Reconnect};
 
 use dns;
-use transport::{DnsNameAndPort, HostAndPort, LookupAddressAndConnect};
+use fully_qualified_authority::FullyQualifiedAuthority;
+use transport::{HostAndPort, LookupAddressAndConnect};
 use timeout::{Timeout, TimeoutError};
 
 mod cache;
@@ -40,9 +41,8 @@ pub struct Background {
     disco: DiscoBg,
 }
 
-pub fn new(default_destination_namespace: String) -> (Control, Background)
-{
-    let (tx, rx) = self::discovery::new(default_destination_namespace);
+pub fn new() -> (Control, Background) {
+    let (tx, rx) = self::discovery::new();
 
     let c = Control {
         disco: tx,
@@ -58,7 +58,7 @@ pub fn new(default_destination_namespace: String) -> (Control, Background)
 // ===== impl Control =====
 
 impl Control {
-    pub fn resolve<B>(&self, auth: &DnsNameAndPort, bind: B) -> Watch<B> {
+    pub fn resolve<B>(&self, auth: &FullyQualifiedAuthority, bind: B) -> Watch<B> {
         self.disco.resolve(auth, bind)
     }
 }
diff --git a/proxy/src/dns.rs b/proxy/src/dns.rs
index a4cb31ab0..39e0b239e 100644
--- a/proxy/src/dns.rs
+++ b/proxy/src/dns.rs
@@ -3,7 +3,6 @@ use abstract_ns::HostResolve;
 use domain;
 use futures::prelude::*;
 use ns_dns_tokio;
-use std::fmt;
 use std::net::IpAddr;
 use std::path::Path;
 use std::str::FromStr;
@@ -19,46 +18,15 @@ pub struct Resolver(ns_dns_tokio::DnsResolver);
 pub enum IpAddrFuture {
     DNS(ns_dns_tokio::HostFuture),
     Fixed(IpAddr),
+    InvalidDNSName(String),
 }
 
 pub enum Error {
+    InvalidDNSName(String),
     NoAddressesFound,
     ResolutionFailed(<ns_dns_tokio::HostFuture as Future>::Error),
 }
 
-/// A DNS name.
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
-pub struct Name(abstract_ns::Name);
-
-impl fmt::Display for Name {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        self.0.fmt(f)
-    }
-}
-
-impl Name {
-    /// Parses the input string as a DNS name, normalizing it to lowercase.
-    pub fn normalize(s: &str) -> Result<Self, ()> {
-        // XXX: `abstract_ns::Name::from_str()` wrongly accepts IP addresses as
-        // domain names. Protect against this. TODO: Fix abstract_ns.
-        if let Ok(_) = IpAddr::from_str(s) {
-            return Err(());
-        }
-        // XXX: `abstract_ns::Name::from_str()` doesn't accept uppercase letters.
-        //  TODO: Avoid this extra allocation.
-        let s = s.to_ascii_lowercase();
-        abstract_ns::Name::from_str(&s)
-            .map(Name)
-            .map_err(|_| ())
-    }
-}
-
-impl AsRef<str> for Name {
-    fn as_ref(&self) -> &str {
-        self.0.as_ref()
-    }
-}
-
 impl Config {
     /// Note that this ignores any errors reading or parsing the resolve.conf
     /// file, just like the `domain` crate does.
@@ -81,7 +49,10 @@ impl Resolver {
         match *host {
             transport::Host::DnsName(ref name) => {
                 trace!("resolve {}", name);
-                IpAddrFuture::DNS(self.0.resolve_host(&name.0))
+                match abstract_ns::Name::from_str(name) {
+                    Ok(name) => IpAddrFuture::DNS(self.0.resolve_host(&name)),
+                    Err(_) => IpAddrFuture::InvalidDNSName(name.clone()),
+                }
             }
             transport::Host::Ip(addr) => IpAddrFuture::Fixed(addr),
         }
@@ -103,55 +74,7 @@ impl Future for IpAddrFuture {
                 Err(e) => Err(Error::ResolutionFailed(e)),
             },
             IpAddrFuture::Fixed(addr) => Ok(Async::Ready(addr)),
-        }
-    }
-}
-
-
-#[cfg(test)]
-mod tests {
-    use super::Name;
-
-    #[test]
-    fn test_dns_name_parsing() {
-        struct Case {
-            input: &'static str,
-            output: &'static str,
-        }
-
-        static VALID: &[Case] = &[
-            // Almost all digits and dots, similar to IPv4 addresses.
-            Case { input: "1.2.3.x", output: "1.2.3.x", },
-            Case { input: "1.2.3.x", output: "1.2.3.x", },
-            Case { input: "1.2.3.4A", output: "1.2.3.4a", },
-            Case { input: "a.1.2.3", output: "a.1.2.3", },
-            Case { input: "1.2.x.3", output: "1.2.x.3", },
-            Case { input: "a.b.c.d", output: "a.b.c.d", },
-
-            // Uppercase letters in labels
-            Case { input: "A.b.c.d", output: "a.b.c.d", },
-            Case { input: "a.mIddle.c", output: "a.middle.c", },
-            Case { input: "a.b.c.D", output: "a.b.c.d", },
-        ];
-
-        for case in VALID {
-            let name = Name::normalize(case.input).expect("is a valid DNS name");
-            assert_eq!(name.as_ref(), case.output);
-        }
-
-        static INVALID: &[&str] = &[
-            "",
-            "1.2.3.4",
-            "::1",
-            "[::1]",
-            ":1234",
-            "1.2.3.4:11234",
-            "abc.com:1234",
-        ];
-
-        for case in INVALID {
-            assert!(Name::normalize(case).is_err(),
-                    "{} is invalid", case);
+            IpAddrFuture::InvalidDNSName(ref name) => Err(Error::InvalidDNSName(name.clone())),
         }
     }
 }
diff --git a/proxy/src/fully_qualified_authority.rs b/proxy/src/fully_qualified_authority.rs
index 52bd85030..1a01e3057 100644
--- a/proxy/src/fully_qualified_authority.rs
+++ b/proxy/src/fully_qualified_authority.rs
@@ -1,28 +1,60 @@
-use bytes::{BytesMut};
+use bytes::BytesMut;
 
-use transport::DnsNameAndPort;
+use std::net::IpAddr;
+use std::str::FromStr;
+
+use http::uri::Authority;
 
 /// A normalized `Authority`.
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-pub struct FullyQualifiedAuthority(String);
+pub struct FullyQualifiedAuthority(Authority);
+
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub struct NamedAddress {
+    pub name: FullyQualifiedAuthority,
+    pub use_destination_service: bool
+}
 
 impl FullyQualifiedAuthority {
     /// Normalizes the name according to Kubernetes service naming conventions.
     /// Case folding is not done; that is done internally inside `Authority`.
-    pub fn normalize(authority: &DnsNameAndPort, default_namespace: &str) -> Option<Self> {
-        let name: &str = authority.host.as_ref();
+    ///
+    /// This assumes the authority is syntactically valid.
+    pub fn normalize(authority: &Authority, default_namespace: &str)
+                     -> NamedAddress
+    {
+        // Don't change IP-address-based authorities.
+        if IpAddr::from_str(authority.host()).is_ok() {
+            return NamedAddress {
+                name: FullyQualifiedAuthority(authority.clone()),
+                use_destination_service: false,
+            }
+        };
+
+        // TODO: `Authority` doesn't have a way to get the serialized form of the
+        // port, so do it ourselves.
+        let (name, colon_port) = {
+            let authority = authority.as_str();
+            match authority.rfind(':') {
+                Some(p) => authority.split_at(p),
+                None => (authority, ""),
+            }
+        };
 
         // parts should have a maximum 4 of pieces (name, namespace, svc, zone)
         let mut parts = name.splitn(4, '.');
 
-        // `dns::Name` guarantees the name has at least one part.
+        // `Authority` guarantees the name has at least one part.
         assert!(parts.next().is_some());
 
         // Rewrite "$name" -> "$name.$default_namespace".
         let has_explicit_namespace = match parts.next() {
             Some("") => {
                 // "$name." is an external absolute name.
-                return None;
+                return NamedAddress {
+                    name: FullyQualifiedAuthority(authority.clone()),
+                    use_destination_service: false,
+                };
             },
             Some(_) => true,
             None => false,
@@ -37,14 +69,20 @@ impl FullyQualifiedAuthority {
         let append_svc = if let Some(part) = parts.next() {
             if !part.eq_ignore_ascii_case("svc") {
                 // If not "$name.$namespace.svc", treat as external.
-                return None;
+                return NamedAddress {
+                    name: FullyQualifiedAuthority(authority.clone()),
+                    use_destination_service: false,
+                };
             }
             false
         } else if has_explicit_namespace {
             true
         } else if namespace_to_append.is_none() {
             // We can't append ".svc" without a namespace, so treat as external.
-            return None;
+            return NamedAddress {
+                name: FullyQualifiedAuthority(authority.clone()),
+                use_destination_service: false,
+            }
         } else {
             true
         };
@@ -62,7 +100,10 @@ impl FullyQualifiedAuthority {
                 // "a.b.svc." is an external absolute name.
                 // "a.b.svc.foo" is external if the default zone is not
                 // "foo".
-                return None;
+                return NamedAddress {
+                    name: FullyQualifiedAuthority(authority.clone()),
+                    use_destination_service: false,
+                }
             }
             (None, strip_last)
         } else {
@@ -80,16 +121,17 @@ impl FullyQualifiedAuthority {
             additional_len += 1 + zone.len(); // "." + zone
         }
 
-        let port_str_len = match authority.port {
-            80 => 0, // XXX: Assumes http://, which is all we support right now.
-            p if p >= 10000 => 1 + 5,
-            p if p >= 1000 => 1 + 4,
-            p if p >= 100 => 1 + 3,
-            p if p >= 10 => 1 + 2,
-            _ => 1,
-        };
+        // If we're not going to change anything then don't allocate anything.
+        if additional_len == 0 && !strip_last {
+            return NamedAddress {
+                name: FullyQualifiedAuthority(authority.clone()),
+                use_destination_service: true,
+            }
+        }
 
-        let mut normalized = BytesMut::with_capacity(name.len() + additional_len + port_str_len);
+        // `authority.as_str().len()` includes the length of `colon_port`.
+        let mut normalized =
+            BytesMut::with_capacity(authority.as_str().len() + additional_len);
         normalized.extend_from_slice(name.as_bytes());
         if let Some(namespace) = namespace_to_append {
             normalized.extend_from_slice(b".");
@@ -102,58 +144,52 @@ impl FullyQualifiedAuthority {
             normalized.extend_from_slice(b".");
             normalized.extend_from_slice(zone.as_bytes());
         }
+        normalized.extend_from_slice(colon_port.as_bytes());
 
         if strip_last {
             let new_len = normalized.len() - 1;
             normalized.truncate(new_len);
         }
 
-        // Append the port
-        if port_str_len > 0 {
-            normalized.extend_from_slice(b":");
-            let port = authority.port.to_string();
-            normalized.extend_from_slice(port.as_ref());
+        let name = Authority::from_shared(normalized.freeze())
+            .expect("syntactically-valid authority");
+        let name = FullyQualifiedAuthority(name);
+        NamedAddress {
+            name,
+            use_destination_service: true,
         }
-
-        Some(FullyQualifiedAuthority(String::from_utf8(normalized.freeze().to_vec()).unwrap()))
     }
 
-    pub fn without_trailing_dot(&self) -> &str {
+    pub fn without_trailing_dot(&self) -> &Authority {
         &self.0
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use transport::{DnsNameAndPort, Host, HostAndPort};
-    use http::uri::Authority;
-    use std::str::FromStr;
-
     #[test]
     fn test_normalized_authority() {
-        fn dns_name_and_port_from_str(input: &str) -> DnsNameAndPort {
-            let authority = Authority::from_str(input).unwrap();
-            match HostAndPort::normalize(&authority, Some(80)) {
-                Ok(HostAndPort { host: Host::DnsName(host), port }) =>
-                    DnsNameAndPort { host, port },
-                Err(e) => {
-                    unreachable!("{:?} when parsing {:?}", e, input)
-                },
-                _ => unreachable!("Not a DNS name: {:?}", input),
-            }
-        }
-
         fn local(input: &str, default_namespace: &str) -> String {
-            let name = dns_name_and_port_from_str(input);
-            let output = super::FullyQualifiedAuthority::normalize(&name, default_namespace);
-            assert!(output.is_some(), "input: {}", input);
-            output.unwrap().without_trailing_dot().into()
+            use bytes::Bytes;
+            use http::uri::Authority;
+
+            let input = Authority::from_shared(Bytes::from(input.as_bytes()))
+                .unwrap();
+            let output = super::FullyQualifiedAuthority::normalize(
+                &input, default_namespace);
+            assert_eq!(output.use_destination_service, true, "input: {}", input);
+            output.name.without_trailing_dot().as_str().into()
         }
 
         fn external(input: &str, default_namespace: &str) {
-            let name = dns_name_and_port_from_str(input);
-            let output = super::FullyQualifiedAuthority::normalize(&name, default_namespace);
-            assert!(output.is_none(), "input: {}", input);
+            use bytes::Bytes;
+            use http::uri::Authority;
+
+            let input = Authority::from_shared(Bytes::from(input.as_bytes())).unwrap();
+            let output = super::FullyQualifiedAuthority::normalize(
+                &input, default_namespace);
+            assert_eq!(output.use_destination_service, false);
+            assert_eq!(output.name.without_trailing_dot().as_str(), input);
         }
 
         assert_eq!("name.namespace.svc.cluster.local", local("name", "namespace"));
@@ -209,10 +245,20 @@ mod tests {
                    local("name.namespace.svc.cluster.local:1234", "namespace"));
 
         // "SVC" is recognized as being equivalent to "svc"
-        assert_eq!("name.namespace.svc.cluster.local",
+        assert_eq!("name.namespace.SVC.cluster.local",
                    local("name.namespace.SVC", "namespace"));
         external("name.namespace.SVC.cluster", "namespace");
-        assert_eq!("name.namespace.svc.cluster.local",
+        assert_eq!("name.namespace.SVC.cluster.local",
                    local("name.namespace.SVC.cluster.local", "namespace"));
+
+        // IPv4 addresses are left unchanged.
+        external("1.2.3.4", "namespace");
+        external("1.2.3.4:1234", "namespace");
+        external("127.0.0.1", "namespace");
+        external("127.0.0.1:8080", "namespace");
+
+        // IPv6 addresses are left unchanged.
+        external("[::1]", "namespace");
+        external("[::1]:1234", "namespace");
     }
 }
diff --git a/proxy/src/lib.rs b/proxy/src/lib.rs
index 5b59ae016..9320af063 100644
--- a/proxy/src/lib.rs
+++ b/proxy/src/lib.rs
@@ -202,10 +202,11 @@ where
             config.metrics_flush_interval,
         );
 
-        let (control, control_bg) = control::new(config.pod_namespace.clone());
+        let (control, control_bg) = control::new();
+
+        let executor = core.handle();
 
         let dns_config = dns::Config::from_file(&config.resolv_conf_path);
-        let executor = core.handle();
 
         let bind = Bind::new(executor.clone()).with_sensors(sensors.clone());
 
diff --git a/proxy/src/outbound.rs b/proxy/src/outbound.rs
index 52bf5854b..244f6e55d 100644
--- a/proxy/src/outbound.rs
+++ b/proxy/src/outbound.rs
@@ -18,10 +18,9 @@ use bind::{self, Bind, Protocol};
 use control::{self, discovery};
 use control::discovery::Bind as BindTrait;
 use ctx;
-use fully_qualified_authority::FullyQualifiedAuthority;
+use fully_qualified_authority::{FullyQualifiedAuthority, NamedAddress};
 use timeout::Timeout;
 use transparency::h1;
-use transport::{DnsNameAndPort, Host, HostAndPort};
 
 type BindProtocol<B> = bind::BindProtocol<Arc<ctx::Proxy>, B>;
 
@@ -53,11 +52,25 @@ impl<B> Outbound<B> {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum Destination {
-    Hostname(DnsNameAndPort),
-    ExplicitIp(SocketAddr),
-    ImplicitOriginalDst(SocketAddr),
+    LocalSvc(FullyQualifiedAuthority),
+    External(SocketAddr),
 }
 
+impl From<FullyQualifiedAuthority> for Destination {
+    #[inline]
+    fn from(authority: FullyQualifiedAuthority) -> Self {
+        Destination::LocalSvc(authority)
+    }
+}
+
+impl From<SocketAddr> for Destination {
+    #[inline]
+    fn from(addr: SocketAddr) -> Self {
+        Destination::External(addr)
+    }
+}
+
+
 impl<B> Recognize for Outbound<B>
 where
     B: tower_h2::Body + 'static,
@@ -79,46 +92,38 @@ where
         // by `NormalizeUri`, as we need to know whether the request will
         // be routed by Host/authority or by SO_ORIGINAL_DST, in order to
         // determine whether the service is reusable.
-        let authority = req.uri().authority_part()
+        let local = req.uri().authority_part()
             .cloned()
         // Therefore, we need to check the host header as well as the URI
         // for a valid authority, before we fall back to SO_ORIGINAL_DST.
-            .or_else(|| h1::authority_from_host(req));
+            .or_else(|| h1::authority_from_host(req))
+            .map(|authority| {
+                FullyQualifiedAuthority::normalize(
+                    &authority,
+                    &self.default_namespace)
+            });
 
-
-        // TODO: Return error when `HostAndPort::normalize()` fails.
-        let mut dest = match authority.as_ref()
-            .and_then(|auth| HostAndPort::normalize(auth, Some(80)).ok()) {
-            Some(HostAndPort { host: Host::DnsName(dns_name), port }) => {
-                let authority = DnsNameAndPort { host: dns_name, port };
-                // Work around the inability of control/discovery.rs to handle unnormalized names.
-                // TODO: Remove this use of `FullyQualifiedAuthority::normalize()` and use
-                // `Destination::Hostname` for all `Host::DnsName` values once DNS machinery is
-                // added to control/discovery.rs.
-                FullyQualifiedAuthority::normalize(&authority, &self.default_namespace)
-                    .map(|_| Destination::Hostname(authority))
-            },
-            Some(HostAndPort { host: Host::Ip(ip), port }) =>
-                Some(Destination::ExplicitIp(SocketAddr::from((ip, port)))),
-            None => None
-        };
-
-        if dest.is_none() {
-            dest = req.extensions()
+        // If we can't fully qualify the authority as a local service,
+        // and there is no original dst, then we have nothing! In that
+        // case, we return `None`, which results an "unrecognized" error.
+        //
+        // In practice, this shouldn't ever happen, since we expect the proxy
+        // to be run on Linux servers, with iptables setup, so there should
+        // always be an original destination.
+        let dest = if let Some(NamedAddress {
+            name,
+            use_destination_service: true
+        }) = local {
+            Destination::LocalSvc(name)
+        } else {
+            let orig_dst = req.extensions()
                 .get::<Arc<ctx::transport::Server>>()
                 .and_then(|ctx| {
                     ctx.orig_dst_if_not_local()
-                })
-                .map(Destination::ImplicitOriginalDst)
+                });
+            Destination::External(orig_dst?)
         };
 
-        // If there is no authority in the request URI or in the Host header,
-        // and there is no original dst, then we have nothing! In that case,
-        // return `None`, which results an "unrecognized" error. In practice,
-        // this shouldn't ever happen, since we expect the proxy to be run on
-        // Linux servers, with iptables setup, so there should always be an
-        // original destination.
-        let dest = dest?;
 
         Some(proto.into_key(dest))
     }
@@ -140,15 +145,16 @@ where
         debug!("building outbound {:?} client to {:?}", protocol, dest);
 
         let resolve = match *dest {
-            Destination::Hostname(ref authority) =>
-                Discovery::NamedSvc(self.discovery.resolve(
+            Destination::LocalSvc(ref authority) => {
+                Discovery::LocalSvc(self.discovery.resolve(
                     authority,
                     self.bind.clone().with_protocol(protocol.clone()),
-                )),
-            Destination::ExplicitIp(addr) =>
-                Discovery::ExplicitIp((addr, self.bind.clone().with_protocol(protocol.clone()))),
-            Destination::ImplicitOriginalDst(addr) =>
-                Discovery::External(Some((addr, self.bind.clone().with_protocol(protocol.clone())))),
+                ))
+            },
+            Destination::External(addr) => {
+                Discovery::External(Some((addr, self.bind.clone()
+                    .with_protocol(protocol.clone()))))
+            }
         };
 
         let loaded = tower_balance::load::WithPendingRequests::new(resolve);
@@ -170,8 +176,7 @@ where
 }
 
 pub enum Discovery<B> {
-    NamedSvc(discovery::Watch<BindProtocol<B>>),
-    ExplicitIp((SocketAddr, BindProtocol<B>)),
+    LocalSvc(discovery::Watch<BindProtocol<B>>),
     External(Option<(SocketAddr, BindProtocol<B>)>),
 }
 
@@ -188,18 +193,8 @@ where
 
     fn poll(&mut self) -> Poll<Change<Self::Key, Self::Service>, Self::DiscoverError> {
         match *self {
-            Discovery::NamedSvc(ref mut w) => w.poll()
+            Discovery::LocalSvc(ref mut w) => w.poll()
                 .map_err(|_| BindError::Internal),
-            Discovery::ExplicitIp((addr, ref bind)) => {
-                // This "discovers" a single address for a fixed IP address
-                // that never has another change. This can mean it floats
-                // in the Balancer forever. However, when we finally add
-                // circuit-breaking, this should be able to take care of itself,
-                // closing down when the connection is no longer usable.
-                let svc = bind.bind(&addr)
-                    .map_err(|_| BindError::External{ addr })?;
-                Ok(Async::Ready(Change::Insert(addr, svc)))
-            },
             Discovery::External(ref mut opt) => {
                 // This "discovers" a single address for an external service
                 // that never has another change. This can mean it floats
diff --git a/proxy/src/transport/connect.rs b/proxy/src/transport/connect.rs
index a46e7b88f..bba7581c0 100644
--- a/proxy/src/transport/connect.rs
+++ b/proxy/src/transport/connect.rs
@@ -9,6 +9,7 @@ use std::str::FromStr;
 use http;
 
 use connection;
+use convert;
 use dns;
 
 #[derive(Debug, Clone)]
@@ -23,24 +24,14 @@ pub struct HostAndPort {
     pub port: u16,
 }
 
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
-pub struct DnsNameAndPort {
-    pub host: dns::Name,
-    pub port: u16,
-}
-
-
 #[derive(Clone, Debug)]
 pub enum Host {
-    DnsName(dns::Name),
+    DnsName(String),
     Ip(IpAddr),
 }
 
 #[derive(Clone, Copy, Debug)]
 pub enum HostAndPortError {
-    /// The host is not a valid DNS name or IP address.
-    InvalidHost,
-
     /// The port is missing.
     MissingPort,
 }
@@ -54,23 +45,17 @@ pub struct LookupAddressAndConnect {
 
 // ===== impl HostAndPort =====
 
-impl HostAndPort {
-    pub fn normalize(a: &http::uri::Authority, default_port: Option<u16>)
-        -> Result<Self, HostAndPortError>
-    {
+impl<'a> convert::TryFrom<&'a http::uri::Authority> for HostAndPort {
+    type Err = HostAndPortError;
+    fn try_from(a: &http::uri::Authority) -> Result<Self, Self::Err> {
         let host = {
-            match dns::Name::normalize(a.host()) {
-                Ok(host) => Host::DnsName(host),
-                Err(_) => {
-                    let ip: IpAddr = IpAddr::from_str(a.host())
-                        .map_err(|_| HostAndPortError::InvalidHost)?;
-                    Host::Ip(ip)
-                },
+            let host = a.host();
+            match IpAddr::from_str(host) {
+                Err(_) => Host::DnsName(host.to_owned()),
+                Ok(ip) => Host::Ip(ip),
             }
         };
-        let port = a.port()
-            .or(default_port)
-            .ok_or_else(|| HostAndPortError::MissingPort)?;
+        let port = a.port().ok_or_else(|| HostAndPortError::MissingPort)?;
         Ok(HostAndPort {
             host,
             port
diff --git a/proxy/src/transport/mod.rs b/proxy/src/transport/mod.rs
index 7f75bedf3..4440de7d5 100644
--- a/proxy/src/transport/mod.rs
+++ b/proxy/src/transport/mod.rs
@@ -3,7 +3,7 @@ mod so_original_dst;
 
 pub use self::connect::{
     Connect,
-    DnsNameAndPort, Host, HostAndPort, HostAndPortError,
+    Host, HostAndPort, HostAndPortError,
     LookupAddressAndConnect,
 };
 pub use self::so_original_dst::{GetOriginalDst, SoOriginalDst};