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-rw-r--r--src/conn.rs17
-rw-r--r--src/error.rs2
-rw-r--r--src/lib.rs26
-rw-r--r--src/message.rs15
-rw-r--r--src/netapp.rs133
-rw-r--r--src/peering/basalt.rs24
-rw-r--r--src/peering/fullmesh.rs12
-rw-r--r--src/proto.rs37
-rw-r--r--src/util.rs6
9 files changed, 206 insertions, 66 deletions
diff --git a/src/conn.rs b/src/conn.rs
index df3b7cf..7f869e8 100644
--- a/src/conn.rs
+++ b/src/conn.rs
@@ -23,10 +23,12 @@ use crate::netapp::*;
use crate::proto::*;
use crate::util::*;
-pub struct ServerConn {
+pub(crate) struct ServerConn {
+ pub(crate) remote_addr: SocketAddr,
+ pub(crate) peer_pk: ed25519::PublicKey,
+
netapp: Arc<NetApp>,
- pub remote_addr: SocketAddr,
- pub peer_pk: ed25519::PublicKey,
+
resp_send: mpsc::UnboundedSender<(RequestID, RequestPriority, Vec<u8>)>,
close_send: watch::Sender<bool>,
}
@@ -115,10 +117,10 @@ impl RecvLoop for ServerConn {
}
}
}
-pub struct ClientConn {
- pub netapp: Arc<NetApp>,
- pub remote_addr: SocketAddr,
- pub peer_pk: ed25519::PublicKey,
+pub(crate) struct ClientConn {
+ pub(crate) remote_addr: SocketAddr,
+ pub(crate) peer_pk: ed25519::PublicKey,
+
query_send: mpsc::UnboundedSender<(RequestID, RequestPriority, Vec<u8>)>,
next_query_number: AtomicU16,
resp_send: mpsc::UnboundedSender<(RequestID, Vec<u8>)>,
@@ -167,7 +169,6 @@ impl ClientConn {
let (close_send, close_recv) = watch::channel(false);
let conn = Arc::new(ClientConn {
- netapp: netapp.clone(),
remote_addr,
peer_pk: remote_pk.clone(),
next_query_number: AtomicU16::from(0u16),
diff --git a/src/error.rs b/src/error.rs
index b54423a..44a3d50 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -41,6 +41,8 @@ impl<T> From<tokio::sync::mpsc::error::SendError<T>> for Error {
}
}
+/// Ths trait adds a `.log_err()` method on `Result<(), E>` types,
+/// which dismisses the error by logging it to stderr.
pub trait LogError {
fn log_err(self, msg: &'static str);
}
diff --git a/src/lib.rs b/src/lib.rs
index 2db8a22..ba365c7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,9 +1,29 @@
+//! Netapp is a Rust library that takes care of a few common tasks in distributed software:
+//!
+//! - establishing secure connections
+//! - managing connection lifetime, reconnecting on failure
+//! - checking peer's state
+//! - peer discovery
+//! - query/response message passing model for communications
+//! - multiplexing transfers over a connection
+//! - overlay networks: full mesh or random peer sampling using Basalt
+//!
+//! Of particular interest, read the documentation for the `netapp::NetApp` type,
+//! the `message::Message` trait, and `proto::RequestPriority` to learn more
+//! about message priorization.
+//! Also check out the examples to learn how to use this crate.
+
#![feature(map_first_last)]
-pub mod conn;
pub mod error;
+pub mod util;
+
+pub mod proto;
pub mod message;
+
+mod conn;
+
pub mod netapp;
pub mod peering;
-pub mod proto;
-pub mod util;
+
+pub use netapp::*;
diff --git a/src/message.rs b/src/message.rs
index bcc5aac..bd54523 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -2,6 +2,21 @@ use serde::{Deserialize, Serialize};
pub type MessageKind = u32;
+/// This trait should be implemented by all messages your application
+/// wants to handle (click to read more).
+///
+/// It defines a `KIND`, which should be a **unique**
+/// `u32` that distinguishes these messages from other types of messages
+/// (it is used by our communication protocol), as well as an associated
+/// `Response` type that defines the type of the response that is given
+/// to the message. It is your responsibility to ensure that `KIND` is a
+/// unique `u32` that is not used by any other protocol messages.
+/// All `KIND` values of the form `0x42xxxxxx` are reserved by the netapp
+/// crate for internal purposes.
+///
+/// A handler for this message has type `Self -> Self::Response`.
+/// If you need to return an error, the `Response` type should be
+/// a `Result<_, _>`.
pub trait Message: Serialize + for<'de> Deserialize<'de> + Send + Sync {
const KIND: MessageKind;
type Response: Serialize + for<'de> Deserialize<'de> + Send + Sync;
diff --git a/src/netapp.rs b/src/netapp.rs
index 25c3b5a..e903f44 100644
--- a/src/netapp.rs
+++ b/src/netapp.rs
@@ -33,17 +33,31 @@ pub(crate) struct Handler {
>,
}
+/// 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.
pub struct NetApp {
pub listen_addr: SocketAddr,
pub netid: auth::Key,
pub pubkey: ed25519::PublicKey,
pub privkey: ed25519::SecretKey,
- pub server_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ServerConn>>>,
- pub client_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ClientConn>>>,
+
+ server_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ServerConn>>>,
+ client_conns: RwLock<HashMap<ed25519::PublicKey, Arc<ClientConn>>>,
+
pub(crate) msg_handlers: ArcSwap<HashMap<MessageKind, Arc<Handler>>>,
- pub(crate) on_connected:
+ on_connected_handler:
ArcSwapOption<Box<dyn Fn(ed25519::PublicKey, SocketAddr, bool) + Send + Sync>>,
- pub(crate) on_disconnected: ArcSwapOption<Box<dyn Fn(ed25519::PublicKey, bool) + Send + Sync>>,
+ on_disconnected_handler: ArcSwapOption<Box<dyn Fn(ed25519::PublicKey, bool) + Send + Sync>>,
}
async fn net_handler_aux<M, F, R>(
@@ -78,13 +92,14 @@ where
F: Fn(ed25519::PublicKey, M) -> R + Send + Sync + 'static,
R: Future<Output = <M as Message>::Response> + Send + Sync,
{
- debug!("Handling message of kind {:08x} from ourself", M::KIND,);
+ debug!("Handling message of kind {:08x} from ourself", M::KIND);
let msg = (msg as Box<dyn Any + 'static>).downcast::<M>().unwrap();
let res = handler(remote, *msg).await;
Box::new(res)
}
impl NetApp {
+ /// Creates a new instance of NetApp. No background process is
pub fn new(
listen_addr: SocketAddr,
netid: auth::Key,
@@ -99,8 +114,8 @@ impl NetApp {
server_conns: RwLock::new(HashMap::new()),
client_conns: RwLock::new(HashMap::new()),
msg_handlers: ArcSwap::new(Arc::new(HashMap::new())),
- on_connected: ArcSwapOption::new(None),
- on_disconnected: ArcSwapOption::new(None),
+ on_connected_handler: ArcSwapOption::new(None),
+ on_disconnected_handler: ArcSwapOption::new(None),
});
let netapp2 = netapp.clone();
@@ -114,6 +129,26 @@ impl NetApp {
netapp
}
+ /// 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.
pub fn add_msg_handler<M, F, R>(&self, handler: F)
where
M: Message + 'static,
@@ -122,10 +157,10 @@ impl NetApp {
{
let handler = Arc::new(handler);
- let handler1 = handler.clone();
+ let handler2 = handler.clone();
let net_handler = Box::new(move |remote: ed25519::PublicKey, bytes: Bytes| {
let fun: Pin<Box<dyn Future<Output = Vec<u8>> + Sync + Send>> =
- Box::pin(net_handler_aux(handler1.clone(), remote, bytes));
+ Box::pin(net_handler_aux(handler2.clone(), remote, bytes));
fun
});
@@ -146,6 +181,8 @@ impl NetApp {
self.msg_handlers.store(Arc::new(handlers));
}
+ /// Main listening process for our app. This future runs during the whole
+ /// run time of our application.
pub async fn listen(self: Arc<Self>) {
let mut listener = TcpListener::bind(self.listen_addr).await.unwrap();
info!("Listening on {}", self.listen_addr);
@@ -166,16 +203,21 @@ impl NetApp {
}
}
+ /// 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`
pub async fn try_connect(
self: Arc<Self>,
ip: SocketAddr,
pk: ed25519::PublicKey,
) -> Result<(), Error> {
+ // Don't connect to ourself, we don't care
+ // but pretend we did
if pk == self.pubkey {
- // Don't connect to ourself, we don't care
- // but pretend we did
tokio::spawn(async move {
- if let Some(h) = self.on_connected.load().as_ref() {
+ if let Some(h) = self.on_connected_handler.load().as_ref() {
h(pk, ip, false);
}
});
@@ -193,11 +235,16 @@ impl NetApp {
Ok(())
}
- pub fn disconnect(self: Arc<Self>, pk: &ed25519::PublicKey) {
+ /// 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) {
+ // Don't disconnect from ourself (we aren't connected anyways)
+ // but pretend we did
if *pk == self.pubkey {
let pk = *pk;
+ let self2 = self.clone();
tokio::spawn(async move {
- if let Some(h) = self.on_disconnected.load().as_ref() {
+ if let Some(h) = self2.on_disconnected_handler.load().as_ref() {
h(pk, false);
}
});
@@ -206,10 +253,30 @@ impl NetApp {
let conn = self.client_conns.read().unwrap().get(pk).cloned();
if let Some(c) = conn {
+ debug!("Closing connection to {} ({})",
+ hex::encode(c.peer_pk),
+ c.remote_addr);
c.close();
}
}
+ /// 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.
pub(crate) fn connected_as_server(&self, id: ed25519::PublicKey, conn: Arc<ServerConn>) {
info!("Accepted connection from {}", hex::encode(id));
@@ -217,8 +284,13 @@ impl NetApp {
conn_list.insert(id.clone(), conn);
}
+ // 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
fn handle_hello_message(&self, id: ed25519::PublicKey, msg: HelloMessage) {
- if let Some(h) = self.on_connected.load().as_ref() {
+ if let Some(h) = self.on_connected_handler.load().as_ref() {
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);
@@ -226,6 +298,9 @@ impl NetApp {
}
}
+ // 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
pub(crate) fn disconnected_as_server(&self, id: &ed25519::PublicKey, conn: Arc<ServerConn>) {
info!("Connection from {} closed", hex::encode(id));
@@ -235,12 +310,19 @@ impl NetApp {
conn_list.remove(id);
}
- if let Some(h) = self.on_disconnected.load().as_ref() {
+ if let Some(h) = self.on_disconnected_handler.load().as_ref() {
h(conn.peer_pk, true);
}
}
}
+ // 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)
pub(crate) fn connected_as_client(&self, id: ed25519::PublicKey, conn: Arc<ClientConn>) {
info!("Connection established to {}", hex::encode(id));
@@ -251,32 +333,39 @@ impl NetApp {
}
}
- if let Some(h) = self.on_connected.load().as_ref() {
+ if let Some(h) = self.on_connected_handler.load().as_ref() {
h(conn.peer_pk, conn.remote_addr, false);
}
+ let server_port = self.listen_addr.port();
tokio::spawn(async move {
- let server_port = conn.netapp.listen_addr.port();
- conn.request(HelloMessage { server_port }, prio::NORMAL)
+ conn.request(HelloMessage { server_port }, PRIO_NORMAL)
.await
.log_err("Sending hello message");
});
}
+ // Called from conn.rs when an outgoinc connection is closed.
+ // The connection is removed from conn_list, and the on_disconnected handler
+ // is called.
pub(crate) fn disconnected_as_client(&self, id: &ed25519::PublicKey, conn: Arc<ClientConn>) {
info!("Connection to {} closed", hex::encode(id));
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);
- }
- if let Some(h) = self.on_disconnected.load().as_ref() {
- h(conn.peer_pk, false);
+ if let Some(h) = self.on_disconnected_handler.load().as_ref() {
+ h(conn.peer_pk, false);
+ }
}
}
}
+ /// 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.
pub async fn request<T>(
&self,
target: &ed25519::PublicKey,
diff --git a/src/peering/basalt.rs b/src/peering/basalt.rs
index 27461ab..5da65e0 100644
--- a/src/peering/basalt.rs
+++ b/src/peering/basalt.rs
@@ -264,18 +264,18 @@ impl Basalt {
});
let basalt2 = basalt.clone();
- netapp.on_connected.store(Some(Arc::new(Box::new(
+ netapp.on_connected(
move |pk: ed25519::PublicKey, addr: SocketAddr, is_incoming: bool| {
basalt2.on_connected(pk, addr, is_incoming);
- },
- ))));
+ }
+ );
let basalt2 = basalt.clone();
- netapp.on_disconnected.store(Some(Arc::new(Box::new(
+ netapp.on_disconnected(
move |pk: ed25519::PublicKey, is_incoming: bool| {
basalt2.on_disconnected(pk, is_incoming);
},
- ))));
+ );
let basalt2 = basalt.clone();
netapp.add_msg_handler::<PullMessage, _, _>(
@@ -331,7 +331,7 @@ impl Basalt {
async fn do_pull(self: Arc<Self>, peer: ed25519::PublicKey) {
match self
.netapp
- .request(&peer, PullMessage {}, prio::NORMAL)
+ .request(&peer, PullMessage {}, PRIO_NORMAL)
.await
{
Ok(resp) => {
@@ -345,7 +345,7 @@ impl Basalt {
async fn do_push(self: Arc<Self>, peer: ed25519::PublicKey) {
let push_msg = self.make_push_message();
- if let Err(e) = self.netapp.request(&peer, push_msg, prio::NORMAL).await {
+ if let Err(e) = self.netapp.request(&peer, push_msg, PRIO_NORMAL).await {
warn!("Error during push exchange: {}", e);
}
}
@@ -448,17 +448,9 @@ impl Basalt {
}
fn close_all_diff(&self, prev_peers: &HashSet<Peer>, new_peers: &HashSet<Peer>) {
- let client_conns = self.netapp.client_conns.read().unwrap();
for peer in prev_peers.iter() {
if !new_peers.contains(peer) {
- if let Some(c) = client_conns.get(&peer.id) {
- debug!(
- "Closing connection to {} ({})",
- hex::encode(peer.id),
- peer.addr
- );
- c.close();
- }
+ self.netapp.disconnect(&peer.id);
}
}
}
diff --git a/src/peering/fullmesh.rs b/src/peering/fullmesh.rs
index 4e9a78d..1b26489 100644
--- a/src/peering/fullmesh.rs
+++ b/src/peering/fullmesh.rs
@@ -177,20 +177,20 @@ impl FullMeshPeeringStrategy {
);
let strat2 = strat.clone();
- netapp.on_connected.store(Some(Arc::new(Box::new(
+ netapp.on_connected(
move |pk: ed25519::PublicKey, addr: SocketAddr, is_incoming: bool| {
let strat2 = strat2.clone();
tokio::spawn(strat2.on_connected(pk, addr, is_incoming));
},
- ))));
+ );
let strat2 = strat.clone();
- netapp.on_disconnected.store(Some(Arc::new(Box::new(
+ netapp.on_disconnected(
move |pk: ed25519::PublicKey, is_incoming: bool| {
let strat2 = strat2.clone();
tokio::spawn(strat2.on_disconnected(pk, is_incoming));
},
- ))));
+ );
strat
}
@@ -271,7 +271,7 @@ impl FullMeshPeeringStrategy {
hex::encode(id),
ping_time
);
- match self.netapp.request(&id, ping_msg, prio::HIGH).await {
+ match self.netapp.request(&id, ping_msg, PRIO_HIGH).await {
Err(e) => warn!("Error pinging {}: {}", hex::encode(id), e),
Ok(ping_resp) => {
let resp_time = Instant::now();
@@ -300,7 +300,7 @@ impl FullMeshPeeringStrategy {
async fn exchange_peers(self: Arc<Self>, id: &ed25519::PublicKey) {
let peer_list = KnownHosts::map_into_vec(&self.known_hosts.read().unwrap().list);
let pex_message = PeerListMessage { list: peer_list };
- match self.netapp.request(id, pex_message, prio::BACKGROUND).await {
+ match self.netapp.request(id, pex_message, PRIO_BACKGROUND).await {
Err(e) => warn!("Error doing peer exchange: {}", e),
Ok(resp) => {
self.handle_peer_list(&resp.list[..]);
diff --git a/src/proto.rs b/src/proto.rs
index 58c914e..b044280 100644
--- a/src/proto.rs
+++ b/src/proto.rs
@@ -16,19 +16,36 @@ use crate::error::*;
use kuska_handshake::async_std::{BoxStreamRead, BoxStreamWrite, TokioCompat};
-const MAX_CHUNK_SIZE: usize = 0x4000;
+/// Priority of a request (click to read more about priorities).
+///
+/// This priority value is used to priorize messages
+/// in the send queue of the client, and their responses in the send queue of the
+/// server. Lower values mean higher priority.
+///
+/// This mechanism is usefull for messages bigger than the maximum chunk size
+/// (set at `0x4000` bytes), such as large file transfers.
+/// In such case, all of the messages in the send queue with the highest priority
+/// will take turns to send individual chunks, in a round-robin fashion.
+/// Once all highest priority messages are sent successfully, the messages with
+/// the next highest priority will begin being sent in the same way.
+///
+/// The same priority value is given to a request and to its associated response.
+pub type RequestPriority = u8;
-pub mod prio {
- pub const HIGH: u8 = 0x20;
- pub const NORMAL: u8 = 0x40;
- pub const BACKGROUND: u8 = 0x80;
+/// Priority class: high
+pub const PRIO_HIGH: RequestPriority = 0x20;
+/// Priority class: normal
+pub const PRIO_NORMAL: RequestPriority = 0x40;
+/// Priority class: background
+pub const PRIO_BACKGROUND: RequestPriority = 0x80;
+/// Priority: primary among given class
+pub const PRIO_PRIMARY: RequestPriority = 0x00;
+/// Priority: secondary among given class (ex: `PRIO_HIGH || PRIO_SECONDARY`)
+pub const PRIO_SECONDARY: RequestPriority = 0x01;
- pub const PRIMARY: u8 = 0x00;
- pub const SECONDARY: u8 = 0x01;
-}
+const MAX_CHUNK_SIZE: usize = 0x4000;
-pub type RequestID = u16;
-pub type RequestPriority = u8;
+pub(crate) type RequestID = u16;
struct SendQueueItem {
id: RequestID,
diff --git a/src/util.rs b/src/util.rs
index e83822e..f09a3bc 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,6 +1,10 @@
use serde::Serialize;
-// util
+/// Utility function: encodes any serializable value in MessagePack binary format
+/// using the RMP library.
+///
+/// Field names and variant names are included in the serialization.
+/// This is used internally by the netapp communication protocol.
pub fn rmp_to_vec_all_named<T>(val: &T) -> Result<Vec<u8>, rmp_serde::encode::Error>
where
T: Serialize + ?Sized,
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-18 22:25:42 +0000