Add MidHandshakeSslStream

Allows recognizing when a stream is still in handshake mode and can gracefully
transition when ready. The blocking usage of the API should still be the same,
just helps nonblocking implementations!

1 files changed, 112 insertions, 8 deletions

diff --git a/openssl/src/ssl/mod.rs b/openssl/src/ssl/mod.rs
index b18df7b3..9215a928 100644
--- a/openssl/src/ssl/mod.rs
+++ b/openssl/src/ssl/mod.rs
@@ -5,6 +5,7 @@ use std::ffi::{CStr, CString};
 use std::fmt;
 use std::io;
 use std::io::prelude::*;
+use std::error as stderror;
 use std::mem;
 use std::str;
 use std::path::Path;
@@ -832,6 +833,10 @@ impl Ssl {
         unsafe { ffi::SSL_accept(self.ssl) }
     }
 
+    fn handshake(&self) -> c_int {
+        unsafe { ffi::SSL_do_handshake(self.ssl) }
+    }
+
     fn read(&self, buf: &mut [u8]) -> c_int {
         let len = cmp::min(c_int::max_value() as usize, buf.len()) as c_int;
         unsafe { ffi::SSL_read(self.ssl, buf.as_ptr() as *mut c_void, len) }
@@ -1081,31 +1086,49 @@ impl<S: Read + Write> SslStream<S> {
     }
 
     /// Creates an SSL/TLS client operating over the provided stream.
-    pub fn connect<T: IntoSsl>(ssl: T, stream: S) -> Result<Self, Error> {
-        let ssl = try!(ssl.into_ssl());
+    pub fn connect<T: IntoSsl>(ssl: T, stream: S)
+                               -> Result<Self, HandshakeError<S>>{
+        let ssl = try!(ssl.into_ssl().map_err(|e| {
+            HandshakeError::Failure(Error::Ssl(e))
+        }));
         let mut stream = Self::new_base(ssl, stream);
         let ret = stream.ssl.connect();
         if ret > 0 {
             Ok(stream)
         } else {
             match stream.make_error(ret) {
-                Error::WantRead(..) | Error::WantWrite(..) => Ok(stream),
-                err => Err(err)
+                e @ Error::WantWrite(_) |
+                e @ Error::WantRead(_) => {
+                    Err(HandshakeError::Interrupted(MidHandshakeSslStream {
+                        stream: stream,
+                        error: e,
+                    }))
+                }
+                err => Err(HandshakeError::Failure(err)),
             }
         }
     }
 
     /// Creates an SSL/TLS server operating over the provided stream.
-    pub fn accept<T: IntoSsl>(ssl: T, stream: S) -> Result<Self, Error> {
-        let ssl = try!(ssl.into_ssl());
+    pub fn accept<T: IntoSsl>(ssl: T, stream: S)
+                              -> Result<Self, HandshakeError<S>> {
+        let ssl = try!(ssl.into_ssl().map_err(|e| {
+            HandshakeError::Failure(Error::Ssl(e))
+        }));
         let mut stream = Self::new_base(ssl, stream);
         let ret = stream.ssl.accept();
         if ret > 0 {
             Ok(stream)
         } else {
             match stream.make_error(ret) {
-                Error::WantRead(..) | Error::WantWrite(..) => Ok(stream),
-                err => Err(err)
+                e @ Error::WantWrite(_) |
+                e @ Error::WantRead(_) => {
+                    Err(HandshakeError::Interrupted(MidHandshakeSslStream {
+                        stream: stream,
+                        error: e,
+                    }))
+                }
+                err => Err(HandshakeError::Failure(err)),
             }
         }
     }
@@ -1137,6 +1160,87 @@ impl<S: Read + Write> SslStream<S> {
     }
 }
 
+/// An error or intermediate state after a TLS handshake attempt.
+#[derive(Debug)]
+pub enum HandshakeError<S> {
+    /// The handshake failed.
+    Failure(Error),
+    /// The handshake was interrupted midway through.
+    Interrupted(MidHandshakeSslStream<S>),
+}
+
+impl<S: Any + fmt::Debug> stderror::Error for HandshakeError<S> {
+    fn description(&self) -> &str {
+        match *self {
+            HandshakeError::Failure(ref e) => e.description(),
+            HandshakeError::Interrupted(ref e) => e.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&stderror::Error> {
+        match *self {
+            HandshakeError::Failure(ref e) => Some(e),
+            HandshakeError::Interrupted(ref e) => Some(&e.error),
+        }
+    }
+}
+
+impl<S: Any + fmt::Debug> fmt::Display for HandshakeError<S> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        try!(f.write_str(stderror::Error::description(self)));
+        if let Some(e) = stderror::Error::cause(self) {
+           try!(write!(f, ": {}", e));
+        }
+        Ok(())
+    }
+}
+
+/// An SSL stream midway through the handshake process.
+#[derive(Debug)]
+pub struct MidHandshakeSslStream<S> {
+    stream: SslStream<S>,
+    error: Error,
+}
+
+impl<S> MidHandshakeSslStream<S> {
+    /// Returns a shared reference to the inner stream.
+    pub fn get_ref(&self) -> &S {
+        self.stream.get_ref()
+    }
+
+    /// Returns a mutable reference to the inner stream.
+    pub fn get_mut(&mut self) -> &mut S {
+        self.stream.get_mut()
+    }
+
+    /// Returns a shared reference to the `SslContext` of the stream.
+    pub fn ssl(&self) -> &Ssl {
+        self.stream.ssl()
+    }
+
+    /// Returns the underlying error which interrupted this handshake.
+    pub fn error(&self) -> &Error {
+        &self.error
+    }
+
+    /// Restarts the handshake process.
+    pub fn handshake(mut self) -> Result<SslStream<S>, HandshakeError<S>> {
+        let ret = self.stream.ssl.handshake();
+        if ret > 0 {
+            Ok(self.stream)
+        } else {
+            match self.stream.make_error(ret) {
+                e @ Error::WantWrite(_) |
+                e @ Error::WantRead(_) => {
+                    self.error = e;
+                    Err(HandshakeError::Interrupted(self))
+                }
+                err => Err(HandshakeError::Failure(err)),
+            }
+        }
+    }
+}
+
 impl<S> SslStream<S> {
     fn make_error(&mut self, ret: c_int) -> Error {
         self.check_panic();