openethereum/util/network-devp2p/src/session.rs
2018-08-17 17:04:03 +03:00

518 lines
17 KiB
Rust

// Copyright 2015-2018 Parity Technologies (UK) Ltd.
// This file is part of Parity.
// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>.
use std::{str, io};
use std::net::SocketAddr;
use std::collections::HashMap;
use std::time::{Duration, Instant};
use mio::*;
use mio::deprecated::{Handler, EventLoop};
use mio::tcp::*;
use ethereum_types::H256;
use rlp::{Rlp, RlpStream, EMPTY_LIST_RLP};
use connection::{EncryptedConnection, Packet, Connection, MAX_PAYLOAD_SIZE};
use handshake::Handshake;
use io::{IoContext, StreamToken};
use network::{Error, ErrorKind, DisconnectReason, SessionInfo, ProtocolId, PeerCapabilityInfo};
use network::SessionCapabilityInfo;
use host::*;
use node_table::NodeId;
use snappy;
// Timeout must be less than (interval - 1).
const PING_TIMEOUT: Duration = Duration::from_secs(60);
const PING_INTERVAL: Duration = Duration::from_secs(120);
const MIN_PROTOCOL_VERSION: u32 = 4;
const MIN_COMPRESSION_PROTOCOL_VERSION: u32 = 5;
#[derive(Debug, Clone)]
enum ProtocolState {
// Packets pending protocol on_connect event return.
Pending(Vec<(Vec<u8>, u8)>),
// Protocol connected.
Connected,
}
/// Peer session over encrypted connection.
/// When created waits for Hello packet exchange and signals ready state.
/// Sends and receives protocol packets and handles basic packets such as ping/pong and disconnect.
pub struct Session {
/// Shared session information
pub info: SessionInfo,
/// Session ready flag. Set after successful Hello packet exchange
had_hello: bool,
/// Session is no longer active flag.
expired: bool,
ping_time: Instant,
pong_time: Option<Instant>,
state: State,
// Protocol states -- accumulates pending packets until signaled as ready.
protocol_states: HashMap<ProtocolId, ProtocolState>,
compression: bool,
}
enum State {
Handshake(Handshake),
Session(EncryptedConnection),
}
/// Structure used to report various session events.
pub enum SessionData {
None,
/// Session is ready to send/receive packets.
Ready,
/// A packet has been received
Packet {
/// Packet data
data: Vec<u8>,
/// Packet protocol ID
protocol: [u8; 3],
/// Zero based packet ID
packet_id: u8,
},
/// Session has more data to be read
Continue,
}
const PACKET_HELLO: u8 = 0x80;
const PACKET_DISCONNECT: u8 = 0x01;
const PACKET_PING: u8 = 0x02;
const PACKET_PONG: u8 = 0x03;
const PACKET_GET_PEERS: u8 = 0x04;
const PACKET_PEERS: u8 = 0x05;
const PACKET_USER: u8 = 0x10;
const PACKET_LAST: u8 = 0x7f;
impl Session {
/// Create a new session out of completed handshake. This clones the handshake connection object
/// and leaves the handshake in limbo to be de-registered from the event loop.
pub fn new<Message>(io: &IoContext<Message>, socket: TcpStream, token: StreamToken, id: Option<&NodeId>,
nonce: &H256, host: &HostInfo) -> Result<Session, Error>
where Message: Send + Clone + Sync + 'static {
let originated = id.is_some();
let mut handshake = Handshake::new(token, id, socket, nonce).expect("Can't create handshake");
let local_addr = handshake.connection.local_addr_str();
handshake.start(io, host, originated)?;
Ok(Session {
state: State::Handshake(handshake),
had_hello: false,
info: SessionInfo {
id: id.cloned(),
client_version: String::new(),
protocol_version: 0,
capabilities: Vec::new(),
peer_capabilities: Vec::new(),
ping: None,
originated,
remote_address: "Handshake".to_owned(),
local_address: local_addr,
},
ping_time: Instant::now(),
pong_time: None,
expired: false,
protocol_states: HashMap::new(),
compression: false,
})
}
fn complete_handshake<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo) -> Result<(), Error> where Message: Send + Sync + Clone {
let connection = if let State::Handshake(ref mut h) = self.state {
self.info.id = Some(h.id);
self.info.remote_address = h.connection.remote_addr_str();
EncryptedConnection::new(h)?
} else {
panic!("Unexpected state");
};
self.state = State::Session(connection);
self.write_hello(io, host)?;
Ok(())
}
fn connection(&self) -> &Connection {
match self.state {
State::Handshake(ref h) => &h.connection,
State::Session(ref s) => &s.connection,
}
}
/// Get id of the remote peer
pub fn id(&self) -> Option<&NodeId> {
self.info.id.as_ref()
}
/// Check if session is ready to send/receive data
pub fn is_ready(&self) -> bool {
self.had_hello
}
/// Mark this session as inactive to be deleted lated.
pub fn set_expired(&mut self) {
self.expired = true;
}
/// Check if this session is expired.
pub fn expired(&self) -> bool {
match self.state {
State::Handshake(ref h) => self.expired || h.expired(),
_ => self.expired,
}
}
/// Check if this session is over and there is nothing to be sent.
pub fn done(&self) -> bool {
self.expired() && !self.connection().is_sending()
}
/// Get remote peer address
pub fn remote_addr(&self) -> io::Result<SocketAddr> {
self.connection().remote_addr()
}
/// Readable IO handler. Returns packet data if available.
pub fn readable<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo) -> Result<SessionData, Error> where Message: Send + Sync + Clone {
if self.expired() {
return Ok(SessionData::None)
}
let mut create_session = false;
let mut packet_data = None;
match self.state {
State::Handshake(ref mut h) => {
h.readable(io, host)?;
if h.done() {
create_session = true;
}
}
State::Session(ref mut c) => {
match c.readable(io)? {
data @ Some(_) => packet_data = data,
None => return Ok(SessionData::None)
}
}
}
if let Some(data) = packet_data {
return Ok(self.read_packet(io, &data, host)?);
}
if create_session {
self.complete_handshake(io, host)?;
io.update_registration(self.token()).unwrap_or_else(|e| debug!(target: "network", "Token registration error: {:?}", e));
}
Ok(SessionData::None)
}
/// Writable IO handler. Sends pending packets.
pub fn writable<Message>(&mut self, io: &IoContext<Message>, _host: &HostInfo) -> Result<(), Error> where Message: Send + Sync + Clone {
match self.state {
State::Handshake(ref mut h) => h.writable(io),
State::Session(ref mut s) => s.writable(io),
}
}
/// Checks if peer supports given capability
pub fn have_capability(&self, protocol: [u8; 3]) -> bool {
self.info.capabilities.iter().any(|c| c.protocol == protocol)
}
/// Checks if peer supports given capability
pub fn capability_version(&self, protocol: [u8; 3]) -> Option<u8> {
self.info.capabilities.iter().filter_map(|c| if c.protocol == protocol { Some(c.version) } else { None }).max()
}
/// Register the session socket with the event loop
pub fn register_socket<Host:Handler<Timeout = Token>>(&self, reg: Token, event_loop: &mut EventLoop<Host>) -> Result<(), Error> {
if self.expired() {
return Ok(());
}
self.connection().register_socket(reg, event_loop)?;
Ok(())
}
/// Update registration with the event loop. Should be called at the end of the IO handler.
pub fn update_socket<Host:Handler>(&self, reg:Token, event_loop: &mut EventLoop<Host>) -> Result<(), Error> {
self.connection().update_socket(reg, event_loop)?;
Ok(())
}
/// Delete registration
pub fn deregister_socket<Host:Handler>(&self, event_loop: &mut EventLoop<Host>) -> Result<(), Error> {
self.connection().deregister_socket(event_loop)?;
Ok(())
}
/// Send a protocol packet to peer.
pub fn send_packet<Message>(&mut self, io: &IoContext<Message>, protocol: Option<[u8; 3]>, packet_id: u8, data: &[u8]) -> Result<(), Error>
where Message: Send + Sync + Clone {
if protocol.is_some() && (self.info.capabilities.is_empty() || !self.had_hello) {
debug!(target: "network", "Sending to unconfirmed session {}, protocol: {:?}, packet: {}", self.token(), protocol.as_ref().map(|p| str::from_utf8(&p[..]).unwrap_or("??")), packet_id);
bail!(ErrorKind::BadProtocol);
}
if self.expired() {
return Err(ErrorKind::Expired.into());
}
let mut i = 0usize;
let pid = match protocol {
Some(protocol) => {
while protocol != self.info.capabilities[i].protocol {
i += 1;
if i == self.info.capabilities.len() {
debug!(target: "network", "Unknown protocol: {:?}", protocol);
return Ok(())
}
}
self.info.capabilities[i].id_offset + packet_id
},
None => packet_id
};
let mut rlp = RlpStream::new();
rlp.append(&(u32::from(pid)));
let mut compressed = Vec::new();
let mut payload = data; // create a reference with local lifetime
if self.compression {
if payload.len() > MAX_PAYLOAD_SIZE {
bail!(ErrorKind::OversizedPacket);
}
let len = snappy::compress_into(&payload, &mut compressed);
trace!(target: "network", "compressed {} to {}", payload.len(), len);
payload = &compressed[0..len];
}
rlp.append_raw(payload, 1);
self.send(io, &rlp.drain())
}
/// Keep this session alive. Returns false if ping timeout happened
pub fn keep_alive<Message>(&mut self, io: &IoContext<Message>) -> bool where Message: Send + Sync + Clone {
if let State::Handshake(_) = self.state {
return true;
}
let timed_out = if let Some(pong) = self.pong_time {
pong.duration_since(self.ping_time) > PING_TIMEOUT
} else {
self.ping_time.elapsed() > PING_TIMEOUT
};
if !timed_out && self.ping_time.elapsed() > PING_INTERVAL {
if let Err(e) = self.send_ping(io) {
debug!("Error sending ping message: {:?}", e);
}
}
!timed_out
}
pub fn token(&self) -> StreamToken {
self.connection().token()
}
/// Signal that a subprotocol has handled the connection successfully and
/// get all pending packets in order received.
pub fn mark_connected(&mut self, protocol: ProtocolId) -> Vec<(ProtocolId, u8, Vec<u8>)> {
match self.protocol_states.insert(protocol, ProtocolState::Connected) {
None => Vec::new(),
Some(ProtocolState::Connected) => {
debug!(target: "network", "Protocol {:?} marked as connected more than once", protocol);
Vec::new()
}
Some(ProtocolState::Pending(pending)) =>
pending.into_iter().map(|(data, id)| (protocol, id, data)).collect(),
}
}
fn read_packet<Message>(&mut self, io: &IoContext<Message>, packet: &Packet, host: &HostInfo) -> Result<SessionData, Error>
where Message: Send + Sync + Clone {
if packet.data.len() < 2 {
return Err(ErrorKind::BadProtocol.into());
}
let packet_id = packet.data[0];
if packet_id != PACKET_HELLO && packet_id != PACKET_DISCONNECT && !self.had_hello {
return Err(ErrorKind::BadProtocol.into());
}
let data = if self.compression {
let compressed = &packet.data[1..];
if snappy::decompressed_len(&compressed)? > MAX_PAYLOAD_SIZE {
bail!(ErrorKind::OversizedPacket);
}
snappy::decompress(&compressed)?
} else {
packet.data[1..].to_owned()
};
match packet_id {
PACKET_HELLO => {
let rlp = Rlp::new(&data); //TODO: validate rlp expected size
self.read_hello(io, &rlp, host)?;
Ok(SessionData::Ready)
},
PACKET_DISCONNECT => {
let rlp = Rlp::new(&data);
let reason: u8 = rlp.val_at(0)?;
if self.had_hello {
debug!(target:"network", "Disconnected: {}: {:?}", self.token(), DisconnectReason::from_u8(reason));
}
Err(ErrorKind::Disconnect(DisconnectReason::from_u8(reason)).into())
}
PACKET_PING => {
self.send_pong(io)?;
Ok(SessionData::Continue)
},
PACKET_PONG => {
let time = Instant::now();
self.pong_time = Some(time);
self.info.ping = Some(time.duration_since(self.ping_time));
Ok(SessionData::Continue)
},
PACKET_GET_PEERS => Ok(SessionData::None), //TODO;
PACKET_PEERS => Ok(SessionData::None),
PACKET_USER ... PACKET_LAST => {
let mut i = 0usize;
while packet_id >= self.info.capabilities[i].id_offset + self.info.capabilities[i].packet_count {
i += 1;
if i == self.info.capabilities.len() {
debug!(target: "network", "Unknown packet: {:?}", packet_id);
return Ok(SessionData::Continue)
}
}
// map to protocol
let protocol = self.info.capabilities[i].protocol;
let protocol_packet_id = packet_id - self.info.capabilities[i].id_offset;
match *self.protocol_states.entry(protocol).or_insert_with(|| ProtocolState::Pending(Vec::new())) {
ProtocolState::Connected => {
trace!(target: "network", "Packet {} mapped to {:?}:{}, i={}, capabilities={:?}", packet_id, protocol, protocol_packet_id, i, self.info.capabilities);
Ok(SessionData::Packet { data, protocol, packet_id: protocol_packet_id } )
}
ProtocolState::Pending(ref mut pending) => {
trace!(target: "network", "Packet {} deferred until protocol connection event completion", packet_id);
pending.push((data, protocol_packet_id));
Ok(SessionData::Continue)
}
}
},
_ => {
debug!(target: "network", "Unknown packet: {:?}", packet_id);
Ok(SessionData::Continue)
}
}
}
fn write_hello<Message>(&mut self, io: &IoContext<Message>, host: &HostInfo) -> Result<(), Error> where Message: Send + Sync + Clone {
let mut rlp = RlpStream::new();
rlp.append_raw(&[PACKET_HELLO as u8], 0);
rlp.begin_list(5)
.append(&host.protocol_version)
.append(&host.client_version())
.append_list(&host.capabilities)
.append(&host.local_endpoint.address.port())
.append(host.id());
self.send(io, &rlp.drain())
}
fn read_hello<Message>(&mut self, io: &IoContext<Message>, rlp: &Rlp, host: &HostInfo) -> Result<(), Error>
where Message: Send + Sync + Clone {
let protocol = rlp.val_at::<u32>(0)?;
let client_version = rlp.val_at::<String>(1)?;
let peer_caps: Vec<PeerCapabilityInfo> = rlp.list_at(2)?;
let id = rlp.val_at::<NodeId>(4)?;
// Intersect with host capabilities
// Leave only highset mutually supported capability version
let mut caps: Vec<SessionCapabilityInfo> = Vec::new();
for hc in &host.capabilities {
if peer_caps.iter().any(|c| c.protocol == hc.protocol && c.version == hc.version) {
caps.push(SessionCapabilityInfo {
protocol: hc.protocol,
version: hc.version,
id_offset: 0,
packet_count: hc.packet_count,
});
}
}
caps.retain(|c| host.capabilities.iter().any(|hc| hc.protocol == c.protocol && hc.version == c.version));
let mut i = 0;
while i < caps.len() {
if caps.iter().any(|c| c.protocol == caps[i].protocol && c.version > caps[i].version) {
caps.remove(i);
} else {
i += 1;
}
}
// Sort capabilities alphabetically.
caps.sort();
i = 0;
let mut offset: u8 = PACKET_USER;
while i < caps.len() {
caps[i].id_offset = offset;
offset += caps[i].packet_count;
i += 1;
}
debug!(target: "network", "Hello: {} v{} {} {:?}", client_version, protocol, id, caps);
let protocol = ::std::cmp::min(protocol, host.protocol_version);
self.info.protocol_version = protocol;
self.info.client_version = client_version;
self.info.capabilities = caps;
self.info.peer_capabilities = peer_caps;
if self.info.capabilities.is_empty() {
trace!(target: "network", "No common capabilities with peer.");
return Err(self.disconnect(io, DisconnectReason::UselessPeer));
}
if protocol < MIN_PROTOCOL_VERSION {
trace!(target: "network", "Peer protocol version mismatch: {}", protocol);
return Err(self.disconnect(io, DisconnectReason::UselessPeer));
}
self.compression = protocol >= MIN_COMPRESSION_PROTOCOL_VERSION;
self.send_ping(io)?;
self.had_hello = true;
Ok(())
}
/// Send ping packet
pub fn send_ping<Message>(&mut self, io: &IoContext<Message>) -> Result<(), Error> where Message: Send + Sync + Clone {
self.send_packet(io, None, PACKET_PING, &EMPTY_LIST_RLP)?;
self.ping_time = Instant::now();
self.pong_time = None;
Ok(())
}
fn send_pong<Message>(&mut self, io: &IoContext<Message>) -> Result<(), Error> where Message: Send + Sync + Clone {
self.send_packet(io, None, PACKET_PONG, &EMPTY_LIST_RLP)
}
/// Disconnect this session
pub fn disconnect<Message>(&mut self, io: &IoContext<Message>, reason: DisconnectReason) -> Error where Message: Send + Sync + Clone {
if let State::Session(_) = self.state {
let mut rlp = RlpStream::new();
rlp.begin_list(1);
rlp.append(&(reason as u32));
self.send_packet(io, None, PACKET_DISCONNECT, &rlp.drain()).ok();
}
ErrorKind::Disconnect(reason).into()
}
fn send<Message>(&mut self, io: &IoContext<Message>, data: &[u8]) -> Result<(), Error> where Message: Send + Sync + Clone {
match self.state {
State::Handshake(_) => {
warn!(target:"network", "Unexpected send request");
},
State::Session(ref mut s) => {
s.send_packet(io, data)?
},
}
Ok(())
}
}