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| 1 | +use std::borrow::Cow; |
| 2 | + |
| 3 | +use tracing::debug; |
| 4 | + |
| 5 | +use crate::{ |
| 6 | + proto::{Decode, Decoded, Encode, MessageType, Packet}, |
| 7 | + Connection, |
| 8 | +}; |
| 9 | + |
| 10 | +pub trait Service { |
| 11 | + fn packet_types(&self) -> &'static [u8]; |
| 12 | + fn handle_packet(&mut self, packet: Packet<'_>); |
| 13 | +} |
| 14 | + |
| 15 | +pub struct ServiceRunner<F> { |
| 16 | + services: Vec<Box<dyn Service>>, |
| 17 | + outgoing_receiver: tokio::sync::mpsc::UnboundedReceiver<Box<dyn Encode>>, |
| 18 | + outgoing_sender: tokio::sync::mpsc::UnboundedSender<Box<dyn Encode>>, |
| 19 | + connection: Connection, |
| 20 | + service_provider: F, |
| 21 | +} |
| 22 | + |
| 23 | +#[derive(Debug, Clone, Copy)] |
| 24 | +#[allow(unused)] |
| 25 | +enum DisconnectReason { |
| 26 | + HostNotAllowedToConnect, |
| 27 | + ProtocolError, |
| 28 | + KeyExchangeFailed, |
| 29 | + Reserved, |
| 30 | + MacError, |
| 31 | + CompressionError, |
| 32 | + ServiceNotAvailable, |
| 33 | + ProtocolVersionNotSupported, |
| 34 | + HostKeyNotVerifiable, |
| 35 | + ConnectionLost, |
| 36 | + ByApplication, |
| 37 | + TooManyConnections, |
| 38 | + AuthCancelledByUser, |
| 39 | + NoMoreAuthMethodsAvailable, |
| 40 | + IllegalUserName, |
| 41 | + Unknown(u32), |
| 42 | +} |
| 43 | + |
| 44 | +impl Encode for DisconnectReason { |
| 45 | + fn encode(&self, buf: &mut Vec<u8>) { |
| 46 | + match self { |
| 47 | + Self::HostNotAllowedToConnect => 1, |
| 48 | + Self::ProtocolError => 2, |
| 49 | + Self::KeyExchangeFailed => 3, |
| 50 | + Self::Reserved => 4, |
| 51 | + Self::MacError => 5, |
| 52 | + Self::CompressionError => 6, |
| 53 | + Self::ServiceNotAvailable => 7, |
| 54 | + Self::ProtocolVersionNotSupported => 8, |
| 55 | + Self::HostKeyNotVerifiable => 9, |
| 56 | + Self::ConnectionLost => 10, |
| 57 | + Self::ByApplication => 11, |
| 58 | + Self::TooManyConnections => 12, |
| 59 | + Self::AuthCancelledByUser => 13, |
| 60 | + Self::NoMoreAuthMethodsAvailable => 14, |
| 61 | + Self::IllegalUserName => 15, |
| 62 | + Self::Unknown(v) => *v, |
| 63 | + } |
| 64 | + .encode(buf); |
| 65 | + } |
| 66 | +} |
| 67 | + |
| 68 | +struct DisconnectMsg(DisconnectReason); |
| 69 | + |
| 70 | +impl Encode for DisconnectMsg { |
| 71 | + fn encode(&self, buf: &mut Vec<u8>) { |
| 72 | + MessageType::Disconnect.encode(buf); |
| 73 | + self.0.encode(buf); |
| 74 | + b"".encode(buf); |
| 75 | + b"".encode(buf); |
| 76 | + } |
| 77 | +} |
| 78 | + |
| 79 | +struct ServiceAcceptMsg<'a> { |
| 80 | + name: Cow<'a, [u8]>, |
| 81 | +} |
| 82 | + |
| 83 | +impl Encode for ServiceAcceptMsg<'_> { |
| 84 | + fn encode(&self, buf: &mut Vec<u8>) { |
| 85 | + MessageType::ServiceAccept.encode(buf); |
| 86 | + self.name.encode(buf); |
| 87 | + } |
| 88 | +} |
| 89 | + |
| 90 | +struct UnimplementedMsg { |
| 91 | + sequence_no: u32, |
| 92 | +} |
| 93 | + |
| 94 | +impl Encode for UnimplementedMsg { |
| 95 | + fn encode(&self, buf: &mut Vec<u8>) { |
| 96 | + MessageType::Unimplemented.encode(buf); |
| 97 | + self.sequence_no.encode(buf); |
| 98 | + } |
| 99 | +} |
| 100 | + |
| 101 | +impl< |
| 102 | + F: FnMut( |
| 103 | + &[u8], |
| 104 | + tokio::sync::mpsc::UnboundedSender<Box<dyn Encode>>, |
| 105 | + ) -> Option<Box<dyn Service>>, |
| 106 | + > ServiceRunner<F> |
| 107 | +{ |
| 108 | + pub fn new(connection: Connection, service_provider: F) -> Self { |
| 109 | + let (outgoing_sender, outgoing_receiver) = tokio::sync::mpsc::unbounded_channel(); |
| 110 | + Self { |
| 111 | + services: vec![], |
| 112 | + outgoing_receiver, |
| 113 | + outgoing_sender, |
| 114 | + connection, |
| 115 | + service_provider, |
| 116 | + } |
| 117 | + } |
| 118 | + |
| 119 | + pub async fn run(mut self) { |
| 120 | + enum SelectResult<'a> { |
| 121 | + Recv(anyhow::Result<Packet<'a>>), |
| 122 | + Send(Option<Box<dyn Encode>>), |
| 123 | + } |
| 124 | + loop { |
| 125 | + let select_result = tokio::select! { |
| 126 | + recv = self.connection.recv_packet() => SelectResult::Recv(recv), |
| 127 | + send = self.outgoing_receiver.recv() => SelectResult::Send(send), |
| 128 | + }; |
| 129 | + |
| 130 | + match select_result { |
| 131 | + SelectResult::Recv(result) => { |
| 132 | + match result { |
| 133 | + Ok(packet) => { |
| 134 | + match MessageType::decode(packet.payload) { |
| 135 | + Ok(Decoded { |
| 136 | + value: MessageType::Disconnect, |
| 137 | + .. |
| 138 | + }) => { |
| 139 | + return; |
| 140 | + } |
| 141 | + Ok(Decoded { |
| 142 | + value: MessageType::Unknown(v), |
| 143 | + .. |
| 144 | + }) => { |
| 145 | + let mut handled = false; |
| 146 | + for service in self.services.iter_mut() { |
| 147 | + if service.packet_types().contains(&v) { |
| 148 | + service.handle_packet(packet); |
| 149 | + handled = true; |
| 150 | + break; |
| 151 | + } |
| 152 | + } |
| 153 | + if !handled { |
| 154 | + // FIXME: send proper packet sequence number |
| 155 | + if let Err(e) = self |
| 156 | + .connection |
| 157 | + .send_packet(&UnimplementedMsg { sequence_no: 0 }) |
| 158 | + .await |
| 159 | + { |
| 160 | + debug!("Error sending packet: {e}"); |
| 161 | + return; |
| 162 | + } |
| 163 | + } |
| 164 | + } |
| 165 | + Ok(Decoded { |
| 166 | + value: MessageType::ServiceRequest, |
| 167 | + next, |
| 168 | + }) => { |
| 169 | + let service_name = match <&[u8]>::decode(next) { |
| 170 | + Ok(Decoded { value, next: &[] }) => value, |
| 171 | + Ok(_) => { |
| 172 | + debug!("Excess bytes in packet, dropping connection"); |
| 173 | + if let Err(e) = self |
| 174 | + .connection |
| 175 | + .send_packet(&DisconnectMsg( |
| 176 | + DisconnectReason::ProtocolError, |
| 177 | + )) |
| 178 | + .await |
| 179 | + { |
| 180 | + debug!("Error sending packet: {e}"); |
| 181 | + } |
| 182 | + return; |
| 183 | + } |
| 184 | + Err(_) => todo!(), |
| 185 | + }; |
| 186 | + |
| 187 | + if let Some(service) = (self.service_provider)( |
| 188 | + service_name, |
| 189 | + self.outgoing_sender.clone(), |
| 190 | + ) { |
| 191 | + self.services.push(service); |
| 192 | + let packet = ServiceAcceptMsg { |
| 193 | + name: service_name.to_vec().into(), |
| 194 | + }; |
| 195 | + if let Err(e) = self.connection.send_packet(&packet).await { |
| 196 | + debug!("Error sending packet: {e}"); |
| 197 | + return; |
| 198 | + } |
| 199 | + } else { |
| 200 | + debug!( |
| 201 | + "Request for unknown service {}", |
| 202 | + String::from_utf8_lossy(service_name) |
| 203 | + ); |
| 204 | + if let Err(e) = self |
| 205 | + .connection |
| 206 | + .send_packet(&DisconnectMsg( |
| 207 | + DisconnectReason::ServiceNotAvailable, |
| 208 | + )) |
| 209 | + .await |
| 210 | + { |
| 211 | + debug!("Error sending packet: {e}"); |
| 212 | + } |
| 213 | + return; |
| 214 | + } |
| 215 | + } |
| 216 | + Ok(_) => { |
| 217 | + // FIXME: Figure out what to do with the other known message types instead of ignoring |
| 218 | + } |
| 219 | + Err(e) => { |
| 220 | + debug!("Error decoding packet type: {e}"); |
| 221 | + if let Err(e) = self |
| 222 | + .connection |
| 223 | + .send_packet(&DisconnectMsg( |
| 224 | + DisconnectReason::ProtocolError, |
| 225 | + )) |
| 226 | + .await |
| 227 | + { |
| 228 | + debug!("Error sending packet: {e}"); |
| 229 | + } |
| 230 | + return; |
| 231 | + } |
| 232 | + } |
| 233 | + } |
| 234 | + Err(e) => { |
| 235 | + debug!("Receiving packet failed with error {e}, dropping connection"); |
| 236 | + return; |
| 237 | + } |
| 238 | + } |
| 239 | + } |
| 240 | + SelectResult::Send(Some(payload)) => { |
| 241 | + if let Err(e) = self.connection.send_packet(&*payload).await { |
| 242 | + debug!("Error sending packet: {e}"); |
| 243 | + return; |
| 244 | + } |
| 245 | + } |
| 246 | + SelectResult::Send(None) => {} |
| 247 | + } |
| 248 | + } |
| 249 | + } |
| 250 | +} |
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