use std::net::TcpStream; use std::time::Duration; use std::io::Read; use crypto::digest::Digest; use crypto::blake2b::Blake2b; use rand::{Rng, OsRng}; use protobuf::Message; use protobuf::parse_from_bytes; use integer_encoding::{VarIntReader, VarIntWriter}; use errors::*; use network_proto::*; #[derive(Debug)] pub enum DatNetMessage { Register(Feed), Handshake(Handshake), Status(Info), Have(Have), Unhave(Unhave), Want(Want), Unwant(Unwant), Request(Request), Cancel(Cancel), Data(Data), } fn msg_code(msg: &DatNetMessage) -> u8 { match msg { &DatNetMessage::Register(_) => 0, &DatNetMessage::Handshake(_) => 1, &DatNetMessage::Status(_) => 2, &DatNetMessage::Have(_) => 3, &DatNetMessage::Unhave(_) => 4, &DatNetMessage::Want(_) => 5, &DatNetMessage::Unwant(_) => 6, &DatNetMessage::Request(_) => 7, &DatNetMessage::Cancel(_) => 8, &DatNetMessage::Data(_) => 9, } } fn msg_sugar(msg: &DatNetMessage) -> &Message { match msg { &DatNetMessage::Register(ref m) => m, &DatNetMessage::Handshake(ref m) => m, &DatNetMessage::Status(ref m) => m, &DatNetMessage::Have(ref m) => m, &DatNetMessage::Unhave(ref m) => m, &DatNetMessage::Want(ref m) => m, &DatNetMessage::Unwant(ref m) => m, &DatNetMessage::Request(ref m) => m, &DatNetMessage::Cancel(ref m) => m, &DatNetMessage::Data(ref m) => m, } } /// Represents a bi-directional connection to a network peer /// /// Spec says nonce is 32 bytes, by dat implementation (hypercore-protocol) is 24 bytes. pub struct DatConnection { nonce: [u8; 24], remote_nonce: [u8; 24], id: [u8; 32], remote_id: [u8; 32], tcp: TcpStream, live: bool, } impl DatConnection { pub fn connect(host_port: &str, key: &[u8], live: bool) -> Result { let timeout = Duration::new(7, 0); let mut rng = OsRng::new()?; let mut nonce = [0; 24]; rng.fill_bytes(&mut nonce); let mut local_id = [0; 32]; rng.fill_bytes(&mut local_id); // Connect to server println!("Connecting to {}", host_port); // TODO: timeout on connect (socketaddr dance) let tcp = TcpStream::connect(host_port)?; tcp.set_read_timeout(Some(timeout))?; tcp.set_write_timeout(Some(timeout))?; let mut dc = DatConnection { nonce: nonce, remote_nonce: [0; 24], id: local_id, tcp, live, remote_id: [0; 32] }; // Exchange register/feed dc.tcp.set_nodelay(true)?; // Faster handshake // calculate discovery key let mut discovery_key = [0; 32]; let mut hash = Blake2b::new_keyed(32, key); hash.input(&"hypercore".as_bytes()); hash.result(&mut discovery_key); // send register let mut register_msg = Feed::new(); register_msg.set_discoveryKey(discovery_key.to_vec()); register_msg.set_nonce(nonce.to_vec()); dc.send_msg(false, &DatNetMessage::Register(register_msg))?; // read register let (was_content, msg) = dc.recv_msg()?; if was_content { bail!("Expected metadata msg, not content"); } if let DatNetMessage::Register(registration) = msg { if registration.get_discoveryKey()[0..32] != discovery_key[..] { bail!("Remote peer not sharing same discovery key"); } // TODO: more satisfying way to do this copy let rn = registration.get_nonce(); for i in 0..24 { dc.remote_nonce[i] = rn[i]; } } else { bail!("Expected Registration message, got something else"); } // send handshake let mut handshake_msg = Handshake::new(); handshake_msg.set_live(live); handshake_msg.set_id(local_id.to_vec()); dc.send_msg(false, &DatNetMessage::Handshake(handshake_msg))?; // read handshake let (was_content, msg) = dc.recv_msg()?; if was_content { bail!("Expected metadata msg, not content"); } if let DatNetMessage::Handshake(handshake) = msg { // TODO: more satisfying way to do this copy let hid = handshake.get_id(); for i in 0..32 { dc.remote_id[i] = hid[i]; } } else { bail!("Expected Handshake message, got something else"); } dc.tcp.set_nodelay(false)?; // Back to normal Ok(dc) } fn send_msg(&mut self, is_content: bool, dnm: &DatNetMessage) -> Result<()> { let header_int: u8 = (is_content as u8) << 4 | (msg_code(dnm) & 0x0F); let msg: &Message = msg_sugar(dnm); let total_message_size = (msg.compute_size() as usize) + 1; println!("SEND total_len={} header={} is_content={}", total_message_size, header_int, is_content); // send both header varints, and data self.tcp.write_varint(total_message_size as u64)?; self.tcp.write_varint(header_int as u32)?; match dnm { &DatNetMessage::Register(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Handshake(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Status(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Have(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Unhave(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Want(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Unwant(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Request(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Cancel(ref m) => m.write_to_writer(&mut self.tcp)?, &DatNetMessage::Data(ref m) => m.write_to_writer(&mut self.tcp)?, } Ok(()) } fn recv_msg(&mut self) -> Result<(bool, DatNetMessage)> { let total_len: u64 = self.tcp.read_varint()?; let header: u8 = self.tcp.read_varint()?; let is_content = (header & (1 << 4)) != 0; if header > 0x1F { bail!("Invalid header received"); } println!("RECV total_len={} header={} is_content={}", total_len, header, is_content); let msg_len = (total_len - 1) as usize; let mut buf = vec![0; msg_len]; self.tcp.read_exact(&mut buf[0..msg_len])?; let dnm = match header & 0x0F { 0 => DatNetMessage::Register(parse_from_bytes::(&mut buf)?), 1 => DatNetMessage::Handshake(parse_from_bytes::(&mut buf)?), 2 => DatNetMessage::Status(parse_from_bytes::(&mut buf)?), 3 => DatNetMessage::Have(parse_from_bytes::(&mut buf)?), 4 => DatNetMessage::Unhave(parse_from_bytes::(&mut buf)?), 5 => DatNetMessage::Want(parse_from_bytes::(&mut buf)?), 6 => DatNetMessage::Unwant(parse_from_bytes::(&mut buf)?), 7 => DatNetMessage::Request(parse_from_bytes::(&mut buf)?), 8 => DatNetMessage::Cancel(parse_from_bytes::(&mut buf)?), 9 => DatNetMessage::Data(parse_from_bytes::(&mut buf)?), other => bail!("Unimplemented message type received: {}", other), }; Ok((is_content, dnm)) } pub fn receive_all(&mut self, is_content: bool) -> Result<()> { // Status: downloading, not uploading let mut sm = Info::new(); sm.set_uploading(false); sm.set_downloading(true); self.send_msg(is_content, &DatNetMessage::Status(sm))?; // Want: everything let mut wm = Want::new(); wm.set_start(0); self.send_msg(is_content, &DatNetMessage::Want(wm))?; // listen for Have let length; loop { let (was_content, msg) = self.recv_msg()?; if was_content != is_content{ continue; } if let DatNetMessage::Have(have) = msg { length = have.get_length(); break; } else { info!("Expected Want message, got: {:?}", &msg); continue; } }; // Request / Data loop for i in 0..length { let mut rm = Request::new(); rm.set_index(i); self.send_msg(is_content, &DatNetMessage::Request(rm))?; let (was_content, msg) = self.recv_msg()?; if was_content != is_content{ info!("Expected other message channel"); } if let DatNetMessage::Data(dm) = msg { println!("Got metadata: {}", dm.get_index()); } else { info!("Expected Data message, got: {:?}", &msg); continue; } } Ok(()) } }