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use std::collections::HashSet;
use std::io;
use std::net::{SocketAddr, UdpSocket};
use std::sync::mpsc::{self, Receiver};
use bip_handshake::Handshaker;
use bip_util::bt::InfoHash;
use bip_util::net;
use mio::Sender;
use router::Router;
use worker::{self, OneshotTask, DhtEvent, ShutdownCause};
/// Maintains a Distributed Hash (Routing) Table.
pub struct MainlineDht {
send: Sender<OneshotTask>,
}
impl MainlineDht {
/// Start the MainlineDht with the given DhtBuilder and Handshaker.
fn with_builder<H>(builder: DhtBuilder, handshaker: H) -> io::Result<MainlineDht>
where H: Handshaker + 'static
{
let send_sock = try!(UdpSocket::bind(&builder.src_addr));
let recv_sock = try!(send_sock.try_clone());
let kill_sock = try!(send_sock.try_clone());
let kill_addr = try!(send_sock.local_addr());
let send = try!(worker::start_mainline_dht(send_sock,
recv_sock,
builder.read_only,
builder.ext_addr,
handshaker,
kill_sock,
kill_addr));
let nodes: Vec<SocketAddr> = builder.nodes.into_iter().collect();
let routers: Vec<Router> = builder.routers.into_iter().collect();
if send.send(OneshotTask::StartBootstrap(routers, nodes)).is_err() {
warn!("bip_dt: MainlineDht failed to send a start bootstrap message...");
}
Ok(MainlineDht { send: send })
}
/// Perform a search for the given InfoHash with an optional announce on the closest nodes.
///
///
/// Announcing will place your contact information in the DHT so others performing lookups
/// for the InfoHash will be able to find your contact information and initiate a handshake.
///
/// If the initial bootstrap has not finished, the search will be queued and executed once
/// the bootstrap has completed.
pub fn search(&self, hash: InfoHash, announce: bool) {
if self.send.send(OneshotTask::StartLookup(hash, announce)).is_err() {
warn!("bip_dht: MainlineDht failed to send a start lookup message...");
}
}
/// An event Receiver which will receive events occuring within the DHT.
///
/// It is important to at least monitor the DHT for shutdown events as any calls
/// after that event occurs will not be processed but no indication will be given.
pub fn events(&self) -> Receiver<DhtEvent> {
let (send, recv) = mpsc::channel();
if self.send.send(OneshotTask::RegisterSender(send)).is_err() {
warn!("bip_dht: MainlineDht failed to send a register sender message...");
// TODO: Should we push a Shutdown event through the sender here? We would need
// to know the cause or create a new cause for this specific scenario since the
// client could have been lazy and wasnt monitoring this until after it shutdown!
}
recv
}
}
impl Drop for MainlineDht {
fn drop(&mut self) {
if self.send.send(OneshotTask::Shutdown(ShutdownCause::ClientInitiated)).is_err() {
warn!("bip_dht: MainlineDht failed to send a shutdown message (may have already been \
shutdown)...");
}
}
}
// ----------------------------------------------------------------------------//
/// Stores information for initializing a DHT.
#[derive(Clone, Debug)]
pub struct DhtBuilder {
nodes: HashSet<SocketAddr>,
routers: HashSet<Router>,
read_only: bool,
src_addr: SocketAddr,
ext_addr: Option<SocketAddr>,
}
impl DhtBuilder {
/// Create a new DhtBuilder.
///
/// This should not be used directly, force the user to supply builder with
/// some initial bootstrap method.
fn new() -> DhtBuilder {
DhtBuilder {
nodes: HashSet::new(),
routers: HashSet::new(),
read_only: true,
src_addr: net::default_route_v4(),
ext_addr: None,
}
}
/// Creates a DhtBuilder with an initial node for our routing table.
pub fn with_node(node_addr: SocketAddr) -> DhtBuilder {
let dht = DhtBuilder::new();
dht.add_node(node_addr)
}
/// Creates a DhtBuilder with an initial router which will let us gather nodes
/// if our routing table is ever empty.
///
/// Difference between a node and a router is that a router is never put in
/// our routing table.
pub fn with_router(router: Router) -> DhtBuilder {
let dht = DhtBuilder::new();
dht.add_router(router)
}
/// Add nodes which will be distributed within our routing table.
pub fn add_node(mut self, node_addr: SocketAddr) -> DhtBuilder {
self.nodes.insert(node_addr);
self
}
/// Add a router which will let us gather nodes if our routing table is ever empty.
///
/// See DhtBuilder::with_router for difference between a router and a node.
pub fn add_router(mut self, router: Router) -> DhtBuilder {
self.routers.insert(router);
self
}
/// Set the read only flag when communicating with other nodes. Indicates
/// that remote nodes should not add us to their routing table.
///
/// Used when we are behind a restrictive NAT and/or we want to decrease
/// incoming network traffic. Defaults value is true.
pub fn set_read_only(mut self, read_only: bool) -> DhtBuilder {
self.read_only = read_only;
self
}
/// Provide the DHT with our external address. If this is not supplied we will
/// have to deduce this information from remote nodes.
///
/// Purpose of the external address is to generate a NodeId that conforms to
/// BEP 42 so that nodes can safely store information on our node.
pub fn set_external_addr(mut self, addr: SocketAddr) -> DhtBuilder {
self.ext_addr = Some(addr);
self
}
/// Provide the DHT with the source address.
///
/// If this is not supplied we will use the OS default route.
pub fn set_source_addr(mut self, addr: SocketAddr) -> DhtBuilder {
self.src_addr = addr;
self
}
/// Start a mainline DHT with the current configuration.
pub fn start_mainline<H>(self, handshaker: H) -> io::Result<MainlineDht>
where H: Handshaker + 'static
{
MainlineDht::with_builder(self, handshaker)
}
}