netapp/src/netapp.rs

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use std::any::Any;
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use std::collections::HashMap;
use std::net::SocketAddr;
use std::pin::Pin;
use std::sync::{Arc, RwLock};
use std::future::Future;
use log::{debug, info};
use arc_swap::{ArcSwap, ArcSwapOption};
use bytes::Bytes;
use sodiumoxide::crypto::auth;
use sodiumoxide::crypto::sign::ed25519;
use tokio::net::{TcpListener, TcpStream};
use crate::conn::*;
use crate::error::*;
use crate::message::*;
use crate::proto::*;
use crate::util::*;
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type DynMsg = Box<dyn Any + Send + Sync + 'static>;
pub(crate) struct Handler {
pub(crate) local_handler:
Box<dyn Fn(DynMsg) -> Pin<Box<dyn Future<Output = DynMsg> + Sync + Send>> + Sync + Send>,
pub(crate) net_handler: Box<
dyn Fn(ed25519::PublicKey, Bytes) -> Pin<Box<dyn Future<Output = Vec<u8>> + Sync + Send>>
+ Sync
+ Send,
>,
}
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/// NetApp is the main class that handles incoming and outgoing connections.
///
/// The `request()` method can be used to send a message to any peer to which we have
/// an outgoing connection, or to ourself. On the server side, these messages are
/// processed by the handlers that have been defined using `add_msg_handler()`.
///
/// NetApp can be used in a stand-alone fashion or together with a peering strategy.
/// If using it alone, you will want to set `on_connect` and `on_disconnect` events
/// in order to manage information about the current peer list.
///
/// It is generally not necessary to use NetApp stand-alone, as the provided full mesh
/// and RPS peering strategies take care of the most common use cases.
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pub struct NetApp {
pub listen_addr: SocketAddr,
pub netid: auth::Key,
pub pubkey: ed25519::PublicKey,
pub privkey: ed25519::SecretKey,
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server_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ServerConn>>>,
client_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ClientConn>>>,
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pub(crate) msg_handlers: ArcSwap<HashMap<MessageKind, Arc<Handler>>>,
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on_connected_handler:
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ArcSwapOption<Box<dyn Fn(ed25519::PublicKey, SocketAddr, bool) + Send + Sync>>,
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on_disconnected_handler: ArcSwapOption<Box<dyn Fn(ed25519::PublicKey, bool) + Send + Sync>>,
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}
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async fn net_handler_aux<M, F, R>(
handler: Arc<F>,
remote: ed25519::PublicKey,
bytes: Bytes,
) -> Vec<u8>
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where
M: Message + 'static,
F: Fn(ed25519::PublicKey, M) -> R + Send + Sync + 'static,
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R: Future<Output = <M as Message>::Response> + Send + Sync,
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{
debug!(
"Handling message of kind {:08x} from {}",
M::KIND,
hex::encode(remote)
);
let res = match rmp_serde::decode::from_read_ref::<_, M>(&bytes[..]) {
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Ok(msg) => Ok(handler(remote, msg).await),
Err(e) => Err(e.to_string()),
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};
rmp_to_vec_all_named(&res).unwrap_or(vec![])
}
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async fn local_handler_aux<M, F, R>(
handler: Arc<F>,
remote: ed25519::PublicKey,
msg: DynMsg,
) -> DynMsg
where
M: Message + 'static,
F: Fn(ed25519::PublicKey, M) -> R + Send + Sync + 'static,
R: Future<Output = <M as Message>::Response> + Send + Sync,
{
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debug!("Handling message of kind {:08x} from ourself", M::KIND);
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let msg = (msg as Box<dyn Any + 'static>).downcast::<M>().unwrap();
let res = handler(remote, *msg).await;
Box::new(res)
}
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impl NetApp {
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/// Creates a new instance of NetApp. No background process is
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pub fn new(
listen_addr: SocketAddr,
netid: auth::Key,
privkey: ed25519::SecretKey,
) -> Arc<Self> {
let pubkey = privkey.public_key();
let netapp = Arc::new(Self {
listen_addr,
netid,
pubkey,
privkey,
server_conns: RwLock::new(HashMap::new()),
client_conns: RwLock::new(HashMap::new()),
msg_handlers: ArcSwap::new(Arc::new(HashMap::new())),
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on_connected_handler: ArcSwapOption::new(None),
on_disconnected_handler: ArcSwapOption::new(None),
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});
let netapp2 = netapp.clone();
netapp.add_msg_handler::<HelloMessage, _, _>(
move |from: ed25519::PublicKey, msg: HelloMessage| {
netapp2.handle_hello_message(from, msg);
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async { () }
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},
);
netapp
}
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/// Set the handler to be called when a new connection (incoming or outgoing) has
/// been successfully established. Do not set this if using a peering strategy,
/// as the peering strategy will need to set this itself.
pub fn on_connected<F>(&self, handler: F)
where F: Fn(ed25519::PublicKey, SocketAddr, bool) + Sized + Send + Sync + 'static
{
self.on_connected_handler.store(Some(Arc::new(Box::new(handler))));
}
/// Set the handler to be called when an existing connection (incoming or outgoing) has
/// been closed by either party. Do not set this if using a peering strategy,
/// as the peering strategy will need to set this itself.
pub fn on_disconnected<F>(&self, handler: F)
where F: Fn(ed25519::PublicKey, bool) + Sized + Send + Sync + 'static
{
self.on_disconnected_handler.store(Some(Arc::new(Box::new(handler))));
}
/// Add a handler for a certain message type. Note that only one handler
/// can be specified for each message type.
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pub fn add_msg_handler<M, F, R>(&self, handler: F)
where
M: Message + 'static,
F: Fn(ed25519::PublicKey, M) -> R + Send + Sync + 'static,
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R: Future<Output = <M as Message>::Response> + Send + Sync + 'static,
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{
let handler = Arc::new(handler);
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let handler2 = handler.clone();
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let net_handler = Box::new(move |remote: ed25519::PublicKey, bytes: Bytes| {
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let fun: Pin<Box<dyn Future<Output = Vec<u8>> + Sync + Send>> =
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Box::pin(net_handler_aux(handler2.clone(), remote, bytes));
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fun
});
let self_id = self.pubkey.clone();
let local_handler = Box::new(move |msg: DynMsg| {
let fun: Pin<Box<dyn Future<Output = DynMsg> + Sync + Send>> =
Box::pin(local_handler_aux(handler.clone(), self_id, msg));
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fun
});
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let funs = Arc::new(Handler {
net_handler,
local_handler,
});
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let mut handlers = self.msg_handlers.load().as_ref().clone();
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handlers.insert(M::KIND, funs);
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self.msg_handlers.store(Arc::new(handlers));
}
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/// Main listening process for our app. This future runs during the whole
/// run time of our application.
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pub async fn listen(self: Arc<Self>) {
let mut listener = TcpListener::bind(self.listen_addr).await.unwrap();
info!("Listening on {}", self.listen_addr);
loop {
// The second item contains the IP and port of the new connection.
let (socket, _) = listener.accept().await.unwrap();
info!(
"Incoming connection from {}, negotiating handshake...",
socket.peer_addr().unwrap()
);
let self2 = self.clone();
tokio::spawn(async move {
ServerConn::run(self2, socket)
.await
.log_err("ServerConn::run");
});
}
}
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/// Attempt to connect to a peer, given by its ip:port and its public key.
/// The public key will be checked during the secret handshake process.
/// This function returns once the connection has been established and a
/// successfull handshake was made. At this point we can send messages to
/// the other node with `Netapp::request`
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pub async fn try_connect(
self: Arc<Self>,
ip: SocketAddr,
pk: ed25519::PublicKey,
) -> Result<(), Error> {
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// Don't connect to ourself, we don't care
// but pretend we did
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if pk == self.pubkey {
tokio::spawn(async move {
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if let Some(h) = self.on_connected_handler.load().as_ref() {
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h(pk, ip, false);
}
});
return Ok(());
}
// Don't connect if already connected
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if self.client_conns.read().unwrap().contains_key(&pk) {
return Ok(());
}
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let socket = TcpStream::connect(ip).await?;
info!("Connected to {}, negotiating handshake...", ip);
ClientConn::init(self, socket, pk.clone()).await?;
Ok(())
}
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/// Close the outgoing connection we have to a node specified by its public key,
/// if such a connection is currently open.
pub fn disconnect(self: &Arc<Self>, pk: &ed25519::PublicKey) {
// If pk is ourself, we're not supposed to have a connection open
if *pk != self.pubkey {
let conn = self.client_conns.read().unwrap().remove(pk);
if let Some(c) = conn {
debug!("Closing connection to {} ({})",
hex::encode(c.peer_pk),
c.remote_addr);
c.close();
} else {
return;
}
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}
// call on_disconnected_handler immediately, since the connection
// was removed
// (if pk == self.pubkey, we pretend we disconnected)
let pk = *pk;
let self2 = self.clone();
tokio::spawn(async move {
if let Some(h) = self2.on_disconnected_handler.load().as_ref() {
h(pk, false);
}
});
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}
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/// Close the incoming connection from a certain client to us,
/// if such a connection is currently open.
pub fn server_disconnect(self: &Arc<Self>, pk: &ed25519::PublicKey) {
let conn = self.server_conns.read().unwrap().get(pk).cloned();
if let Some(c) = conn {
debug!("Closing incoming connection from {} ({})",
hex::encode(c.peer_pk),
c.remote_addr);
c.close();
}
}
// Called from conn.rs when an incoming connection is successfully established
// Registers the connection in our list of connections
// Do not yet call the on_connected handler, because we don't know if the remote
// has an actual IP address and port we can call them back on.
// We will know this when they send a Hello message, which is handled below.
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pub(crate) fn connected_as_server(&self, id: ed25519::PublicKey, conn: Arc<ServerConn>) {
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info!("Accepted connection from {}", hex::encode(id));
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let mut conn_list = self.server_conns.write().unwrap();
conn_list.insert(id.clone(), conn);
}
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// Handle hello message from a client. This message is used for them to tell us
// that they are listening on a certain port number on which we can call them back.
// At this point we know they are a full network member, and not just a client,
// and we call the on_connected handler so that the peering strategy knows
// we have a new potential peer
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fn handle_hello_message(&self, id: ed25519::PublicKey, msg: HelloMessage) {
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if let Some(h) = self.on_connected_handler.load().as_ref() {
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if let Some(c) = self.server_conns.read().unwrap().get(&id) {
let remote_addr = SocketAddr::new(c.remote_addr.ip(), msg.server_port);
h(id, remote_addr, true);
}
}
}
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// Called from conn.rs when an incoming connection is closed.
// We deregister the connection from server_conns and call the
// handler registered by on_disconnected
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pub(crate) fn disconnected_as_server(&self, id: &ed25519::PublicKey, conn: Arc<ServerConn>) {
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info!("Connection from {} closed", hex::encode(id));
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let mut conn_list = self.server_conns.write().unwrap();
if let Some(c) = conn_list.get(id) {
if Arc::ptr_eq(c, &conn) {
conn_list.remove(id);
}
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if let Some(h) = self.on_disconnected_handler.load().as_ref() {
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h(conn.peer_pk, true);
}
}
}
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// Called from conn.rs when an outgoinc connection is successfully established.
// The connection is registered in self.client_conns, and the
// on_connected handler is called.
//
// Since we are ourself listening, we send them a Hello message so that
// they know on which port to call us back. (TODO: don't do this if we are
// just a simple client and not a full p2p node)
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pub(crate) fn connected_as_client(&self, id: ed25519::PublicKey, conn: Arc<ClientConn>) {
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info!("Connection established to {}", hex::encode(id));
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{
let mut conn_list = self.client_conns.write().unwrap();
if let Some(old_c) = conn_list.insert(id.clone(), conn.clone()) {
tokio::spawn(async move { old_c.close() });
}
}
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if let Some(h) = self.on_connected_handler.load().as_ref() {
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h(conn.peer_pk, conn.remote_addr, false);
}
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let server_port = self.listen_addr.port();
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tokio::spawn(async move {
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conn.request(HelloMessage { server_port }, PRIO_NORMAL)
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.await
.log_err("Sending hello message");
});
}
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// Called from conn.rs when an outgoinc connection is closed.
// The connection is removed from conn_list, and the on_disconnected handler
// is called.
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pub(crate) fn disconnected_as_client(&self, id: &ed25519::PublicKey, conn: Arc<ClientConn>) {
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info!("Connection to {} closed", hex::encode(id));
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let mut conn_list = self.client_conns.write().unwrap();
if let Some(c) = conn_list.get(id) {
if Arc::ptr_eq(c, &conn) {
conn_list.remove(id);
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if let Some(h) = self.on_disconnected_handler.load().as_ref() {
h(conn.peer_pk, false);
}
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}
}
// else case: happens if connection was removed in .disconnect()
// in which case on_disconnected_handler was already called
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}
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/// Send a message to a remote host to which a client connection is already
/// established, and await their response. The target is the id of the peer we
/// want to send the message to.
/// The priority is an `u8`, with lower numbers meaning highest priority.
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pub async fn request<T>(
&self,
target: &ed25519::PublicKey,
rq: T,
prio: RequestPriority,
) -> Result<<T as Message>::Response, Error>
where
T: Message + 'static,
{
if *target == self.pubkey {
let handler = self.msg_handlers.load().get(&T::KIND).cloned();
match handler {
None => Err(Error::Message(format!(
"No handler registered for message kind {:08x}",
T::KIND
))),
Some(h) => {
let local_handler = &h.local_handler;
let res = local_handler(Box::new(rq)).await;
let res_t = (res as Box<dyn Any + 'static>)
.downcast::<<T as Message>::Response>()
.unwrap();
Ok(*res_t)
}
}
} else {
let conn = self.client_conns.read().unwrap().get(target).cloned();
match conn {
None => Err(Error::Message(format!(
"Not connected: {}",
hex::encode(target)
))),
Some(c) => c.request(rq, prio).await,
}
}
}
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}