add password protocol extension, simplify protocol extension api

wisp/src/extensions.rs

@@ -88,7 +88,7 @@ pub trait ProtocolExtension: std::fmt::Debug {
     fn box_clone(&self) -> Box<dyn ProtocolExtension + Sync + Send>;
 }
 
-/// Trait to build a Wisp protocol extension for the client.
+/// Trait to build a Wisp protocol extension from a payload.
 pub trait ProtocolExtensionBuilder {
     /// Get the protocol extension ID.
     ///
@@ -96,7 +96,11 @@ pub trait ProtocolExtensionBuilder {
     fn get_id(&self) -> u8;
 
     /// Build a protocol extension from the extension's metadata.
-    fn build(&self, bytes: Bytes, role: Role) -> AnyProtocolExtension;
+    fn build_from_bytes(&self, bytes: Bytes, role: Role)
+        -> Result<AnyProtocolExtension, WispError>;
+
+    /// Build a protocol extension to send to the other side.
+    fn build_to_extension(&self, role: Role) -> AnyProtocolExtension;
 }
 
 pub mod udp {
@@ -108,7 +112,6 @@ pub mod udp {
     //!     rx,
     //!     tx,
     //!     128,
-    //!     Some(vec![UdpProtocolExtension().into()]),
     //!     Some(&[&UdpProtocolExtensionBuilder()])
     //! );
     //! ```
@@ -154,7 +157,6 @@ pub mod udp {
             Ok(())
         }
 
-        /// Handle receiving a packet.
         async fn handle_packet(
             &mut self,
             _: Bytes,
@@ -180,11 +182,294 @@ pub mod udp {
 
     impl ProtocolExtensionBuilder for UdpProtocolExtensionBuilder {
         fn get_id(&self) -> u8 {
-            0x01
+            UdpProtocolExtension::ID
         }
 
-        fn build(&self, _: Bytes, _: crate::Role) -> AnyProtocolExtension {
-            AnyProtocolExtension(Box::new(UdpProtocolExtension()))
+        fn build_from_bytes(
+            &self,
+            _: Bytes,
+            _: crate::Role,
+        ) -> Result<AnyProtocolExtension, WispError> {
+            Ok(UdpProtocolExtension().into())
+        }
+
+        fn build_to_extension(&self, _: crate::Role) -> AnyProtocolExtension {
+            UdpProtocolExtension().into()
+        }
+    }
+}
+
+pub mod password {
+    //! Password protocol extension.
+    //!
+    //! # Example
+    //! Server:
+    //! ```
+    //! let mut passwords = HashMap::new();
+    //! passwords.insert("user1".to_string(), "pw".to_string());
+    //! let (mux, fut) = ServerMux::new(
+    //!     rx,
+    //!     tx,
+    //!     128,
+    //!     Some(&[&PasswordProtocolExtensionBuilder::new_server(passwords)])
+    //! );
+    //! ```
+    //!
+    //! Client:
+    //! ```
+    //! let (mux, fut) = ClientMux::new(
+    //!     rx,
+    //!     tx,
+    //!     128,
+    //!     Some(&[
+    //!         &PasswordProtocolExtensionBuilder::new_client(
+    //!             "user1".to_string(),
+    //!             "pw".to_string()
+    //!         )
+    //!     ])
+    //! );
+    //! ```
+    //! See [the docs](https://github.com/MercuryWorkshop/wisp-protocol/blob/main/protocol.md#0x02---password-authentication)
+
+    use std::{collections::HashMap, error::Error, fmt::Display, string::FromUtf8Error};
+
+    use async_trait::async_trait;
+    use bytes::{Buf, BufMut, Bytes, BytesMut};
+
+    use crate::{
+        ws::{LockedWebSocketWrite, WebSocketRead},
+        Role, WispError,
+    };
+
+    use super::{AnyProtocolExtension, ProtocolExtension, ProtocolExtensionBuilder};
+
+    #[derive(Debug, Clone)]
+    /// Password protocol extension.
+    ///
+    /// **This extension will panic when encoding if the username's length does not fit within a u8
+    /// or the password's length does not fit within a u16.**
+    pub struct PasswordProtocolExtension {
+        /// The username to log in with.
+        ///
+        /// This string's length must fit within a u8.
+        pub username: String,
+        /// The password to log in with.
+        ///
+        /// This string's length must fit within a u16.
+        pub password: String,
+        role: Role,
+    }
+
+    impl PasswordProtocolExtension {
+        /// Password protocol extension ID.
+        pub const ID: u8 = 0x02;
+
+        /// Create a new password protocol extension for the server.
+        ///
+        /// This signifies that the server requires a password.
+        pub fn new_server() -> Self {
+            Self {
+                username: String::new(),
+                password: String::new(),
+                role: Role::Server,
+            }
+        }
+
+        /// Create a new password protocol extension for the client, with a username and password.
+        ///
+        /// The username's length must fit within a u8. The password's length must fit within a
+        /// u16.
+        pub fn new_client(username: String, password: String) -> Self {
+            Self {
+                username,
+                password,
+                role: Role::Client,
+            }
+        }
+    }
+
+    #[async_trait]
+    impl ProtocolExtension for PasswordProtocolExtension {
+        fn get_id(&self) -> u8 {
+            Self::ID
+        }
+
+        fn get_supported_packets(&self) -> &'static [u8] {
+            &[]
+        }
+
+        fn encode(&self) -> Bytes {
+            match self.role {
+                Role::Server => Bytes::new(),
+                Role::Client => {
+                    let username = Bytes::from(self.username.clone().into_bytes());
+                    let password = Bytes::from(self.password.clone().into_bytes());
+                    let username_len = u8::try_from(username.len()).expect("username was too long");
+                    let password_len =
+                        u16::try_from(username.len()).expect("password was too long");
+
+                    let mut bytes =
+                        BytesMut::with_capacity(3 + username_len as usize + password_len as usize);
+                    bytes.put_u8(username_len);
+                    bytes.put_u16_le(password_len);
+                    bytes.extend(username);
+                    bytes.extend(password);
+                    bytes.freeze()
+                }
+            }
+        }
+
+        async fn handle_handshake(
+            &mut self,
+            _: &mut dyn WebSocketRead,
+            _: &LockedWebSocketWrite,
+        ) -> Result<(), WispError> {
+            Ok(())
+        }
+
+        async fn handle_packet(
+            &mut self,
+            _: Bytes,
+            _: &mut dyn WebSocketRead,
+            _: &LockedWebSocketWrite,
+        ) -> Result<(), WispError> {
+            Ok(())
+        }
+
+        fn box_clone(&self) -> Box<dyn ProtocolExtension + Sync + Send> {
+            Box::new(self.clone())
+        }
+    }
+
+    #[derive(Debug)]
+    enum PasswordProtocolExtensionError {
+        Utf8Error(FromUtf8Error),
+        InvalidUsername,
+        InvalidPassword,
+    }
+
+    impl Display for PasswordProtocolExtensionError {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            use PasswordProtocolExtensionError as E;
+            match self {
+                E::Utf8Error(e) => write!(f, "{}", e),
+                E::InvalidUsername => write!(f, "Invalid username"),
+                E::InvalidPassword => write!(f, "Invalid password"),
+            }
+        }
+    }
+
+    impl Error for PasswordProtocolExtensionError {}
+
+    impl From<PasswordProtocolExtensionError> for WispError {
+        fn from(value: PasswordProtocolExtensionError) -> Self {
+            WispError::ExtensionImplError(Box::new(value))
+        }
+    }
+
+    impl From<FromUtf8Error> for PasswordProtocolExtensionError {
+        fn from(value: FromUtf8Error) -> Self {
+            PasswordProtocolExtensionError::Utf8Error(value)
+        }
+    }
+
+    impl From<PasswordProtocolExtension> for AnyProtocolExtension {
+        fn from(value: PasswordProtocolExtension) -> Self {
+            AnyProtocolExtension(Box::new(value))
+        }
+    }
+
+    /// Password protocol extension builder. 
+    pub struct PasswordProtocolExtensionBuilder {
+        /// Map of users and their passwords to allow. Only used on server.
+        pub users: HashMap<String, String>,
+        /// Username to authenticate with. Only used on client.
+        pub username: String,
+        /// Password to authenticate with. Only used on client.
+        pub password: String,
+    }
+
+    impl PasswordProtocolExtensionBuilder {
+        /// Create a new password protocol extension builder for the server, with a map of users
+        /// and passwords to allow.
+        pub fn new_server(users: HashMap<String, String>) -> Self {
+            Self {
+                users,
+                username: String::new(),
+                password: String::new(),
+            }
+        }
+
+        /// Create a new password protocol extension builder for the client, with a username and
+        /// password to authenticate with.
+        pub fn new_client(username: String, password: String) -> Self {
+            Self {
+                users: HashMap::new(),
+                username,
+                password,
+            }
+        }
+    }
+
+    impl ProtocolExtensionBuilder for PasswordProtocolExtensionBuilder {
+        fn get_id(&self) -> u8 {
+            PasswordProtocolExtension::ID
+        }
+
+        fn build_from_bytes(
+            &self,
+            mut payload: Bytes,
+            role: crate::Role,
+        ) -> Result<AnyProtocolExtension, WispError> {
+            match role {
+                Role::Server => {
+                    if payload.remaining() < 3 {
+                        return Err(WispError::PacketTooSmall);
+                    }
+
+                    let username_len = payload.get_u8();
+                    let password_len = payload.get_u16_le();
+                    if payload.remaining() < (password_len + username_len as u16) as usize {
+                        return Err(WispError::PacketTooSmall);
+                    }
+
+                    use PasswordProtocolExtensionError as EError;
+                    let username =
+                        String::from_utf8(payload.copy_to_bytes(username_len as usize).to_vec())
+                            .map_err(|x| WispError::from(EError::from(x)))?;
+                    let password =
+                        String::from_utf8(payload.copy_to_bytes(password_len as usize).to_vec())
+                            .map_err(|x| WispError::from(EError::from(x)))?;
+
+                    let Some(user) = self.users.iter().find(|x| *x.0 == username) else {
+                        return Err(EError::InvalidUsername.into());
+                    };
+
+                    if *user.1 != password {
+                        return Err(EError::InvalidPassword.into());
+                    }
+                    Ok(PasswordProtocolExtension {
+                        username,
+                        password,
+                        role,
+                    }
+                    .into())
+                }
+                Role::Client => {
+                    Ok(PasswordProtocolExtension::new_client(String::new(), String::new()).into())
+                }
+            }
+        }
+
+        fn build_to_extension(&self, role: Role) -> AnyProtocolExtension {
+            match role {
+                Role::Server => PasswordProtocolExtension::new_server(),
+                Role::Client => PasswordProtocolExtension::new_client(
+                    self.username.clone(),
+                    self.password.clone(),
+                ),
+            }
+            .into()
         }
     }
 }

wisp/src/lib.rs

@@ -458,13 +458,11 @@ pub struct ServerMux {
 impl ServerMux {
     /// Create a new server-side multiplexor.
     ///
-    /// If either extensions or extension_builders are None a Wisp v1 connection is created
-    /// otherwise a Wisp v2 connection is created.
+    /// If extension_builders is None a Wisp v1 connection is created otherwise a Wisp v2 connection is created.
     pub async fn new<R, W>(
         mut read: R,
         write: W,
         buffer_size: u32,
-        extensions: Option<Vec<AnyProtocolExtension>>,
         extension_builders: Option<&[&(dyn ProtocolExtensionBuilder + Sync)]>,
     ) -> Result<(Self, impl Future<Output = Result<(), WispError>> + Send), WispError>
     where
@@ -483,15 +481,17 @@ impl ServerMux {
         let mut extra_packet = Vec::with_capacity(1);
         let mut downgraded = true;
 
-        if let Some(extensions) = extensions {
         if let Some(builders) = extension_builders {
+            let extensions: Vec<_> = builders
+                .iter()
+                .map(|x| x.build_to_extension(Role::Server))
+                .collect();
             let extension_ids: Vec<_> = extensions.iter().map(|x| x.get_id()).collect();
             write
                 .write_frame(Packet::new_info(extensions).into())
                 .await?;
             if let Some(frame) = select! {
                 x = read.wisp_read_frame(&write).fuse() => Some(x?),
-                    // TODO change this to correct timeout once draft 2 is out
                 _ = Delay::new(Duration::from_secs(5)).fuse() => None
             } {
                 let packet = Packet::maybe_parse_info(frame, Role::Server, builders)?;
@@ -507,7 +507,6 @@ impl ServerMux {
                 }
             }
         }
-        }
 
         Ok((
             Self {
@@ -574,12 +573,10 @@ pub struct ClientMux {
 impl ClientMux {
     /// Create a new client side multiplexor.
     ///
-    /// If either extensions or extension_builders are None a Wisp v1 connection is created
-    /// otherwise a Wisp v2 connection is created.
+    /// If extension_builders is None a Wisp v1 connection is created otherwise a Wisp v2 connection is created.
     pub async fn new<R, W>(
         mut read: R,
         write: W,
-        extensions: Option<Vec<AnyProtocolExtension>>,
         extension_builders: Option<&[&(dyn ProtocolExtensionBuilder + Sync)]>,
     ) -> Result<(Self, impl Future<Output = Result<(), WispError>> + Send), WispError>
     where
@@ -596,12 +593,14 @@ impl ClientMux {
             let mut extra_packet = Vec::with_capacity(1);
             let mut downgraded = true;
 
-            if let Some(extensions) = extensions {
             if let Some(builders) = extension_builders {
+                let extensions: Vec<_> = builders
+                    .iter()
+                    .map(|x| x.build_to_extension(Role::Client))
+                    .collect();
                 let extension_ids: Vec<_> = extensions.iter().map(|x| x.get_id()).collect();
                 if let Some(frame) = select! {
                     x = read.wisp_read_frame(&write).fuse() => Some(x?),
-                        // TODO change this to correct timeout once draft 2 is out
                     _ = Delay::new(Duration::from_secs(5)).fuse() => None
                 } {
                     let packet = Packet::maybe_parse_info(frame, Role::Server, builders)?;
@@ -620,7 +619,6 @@ impl ClientMux {
                     }
                 }
             }
-            }
 
             for extension in supported_extensions.iter_mut() {
                 extension.handle_handshake(&mut read, &write).await?;

wisp/src/packet.rs

@@ -444,7 +444,9 @@ impl Packet {
                 return Err(WispError::PacketTooSmall);
             }
             if let Some(builder) = extension_builders.iter().find(|x| x.get_id() == id) {
-                extensions.push(builder.build(bytes.copy_to_bytes(length), role))
+                if let Ok(extension) = builder.build_from_bytes(bytes.copy_to_bytes(length), role) {
+                    extensions.push(extension)
+                }
             } else {
                 bytes.advance(length)
             }