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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// This file implements a server that can handle multiple connections.
use std::{
cell::RefCell,
cmp::min,
collections::HashSet,
ops::{Deref, DerefMut},
path::PathBuf,
rc::Rc,
time::Instant,
};
use neqo_common::{
event::Provider, hex, qdebug, qerror, qinfo, qlog::NeqoQlog, qtrace, qwarn, Datagram, Role,
};
use neqo_crypto::{
encode_ech_config, AntiReplay, Cipher, PrivateKey, PublicKey, ZeroRttCheckResult,
ZeroRttChecker,
};
pub use crate::addr_valid::ValidateAddress;
use crate::{
addr_valid::{AddressValidation, AddressValidationResult},
cid::{ConnectionId, ConnectionIdGenerator, ConnectionIdRef},
connection::{Connection, Output, State},
packet::{PacketBuilder, PacketType, PublicPacket, MIN_INITIAL_PACKET_SIZE},
ConnectionParameters, Res, Version,
};
/// A `ServerZeroRttChecker` is a simple wrapper around a single checker.
/// It uses `RefCell` so that the wrapped checker can be shared between
/// multiple connections created by the server.
#[derive(Clone, Debug)]
struct ServerZeroRttChecker {
checker: Rc<RefCell<Box<dyn ZeroRttChecker>>>,
}
impl ServerZeroRttChecker {
pub fn new(checker: Box<dyn ZeroRttChecker>) -> Self {
Self {
checker: Rc::new(RefCell::new(checker)),
}
}
}
impl ZeroRttChecker for ServerZeroRttChecker {
fn check(&self, token: &[u8]) -> ZeroRttCheckResult {
self.checker.borrow().check(token)
}
}
/// `InitialDetails` holds important information for processing `Initial` packets.
struct InitialDetails {
src_cid: ConnectionId,
dst_cid: ConnectionId,
token: Vec<u8>,
version: Version,
}
impl InitialDetails {
fn new(packet: &PublicPacket) -> Self {
Self {
src_cid: ConnectionId::from(packet.scid()),
dst_cid: ConnectionId::from(packet.dcid()),
token: packet.token().to_vec(),
version: packet.version().unwrap(),
}
}
}
struct EchConfig {
config: u8,
public_name: String,
sk: PrivateKey,
pk: PublicKey,
encoded: Vec<u8>,
}
impl EchConfig {
fn new(config: u8, public_name: &str, sk: &PrivateKey, pk: &PublicKey) -> Res<Self> {
let encoded = encode_ech_config(config, public_name, pk)?;
Ok(Self {
config,
public_name: String::from(public_name),
sk: sk.clone(),
pk: pk.clone(),
encoded,
})
}
}
pub struct Server {
/// The names of certificates.
certs: Vec<String>,
/// The ALPN values that the server supports.
protocols: Vec<String>,
/// The cipher suites that the server supports.
ciphers: Vec<Cipher>,
/// Anti-replay configuration for 0-RTT.
anti_replay: AntiReplay,
/// A function for determining if 0-RTT can be accepted.
zero_rtt_checker: ServerZeroRttChecker,
/// A connection ID generator.
cid_generator: Rc<RefCell<dyn ConnectionIdGenerator>>,
/// Connection parameters.
conn_params: ConnectionParameters,
/// All connections.
connections: Vec<Rc<RefCell<Connection>>>,
/// Address validation logic, which determines whether we send a Retry.
address_validation: Rc<RefCell<AddressValidation>>,
/// Directory to create qlog traces in
qlog_dir: Option<PathBuf>,
/// Encrypted client hello (ECH) configuration.
ech_config: Option<EchConfig>,
}
impl Server {
/// Construct a new server.
/// * `now` is the time that the server is instantiated.
/// * `certs` is a list of the certificates that should be configured.
/// * `protocols` is the preference list of ALPN values.
/// * `anti_replay` is an anti-replay context.
/// * `zero_rtt_checker` determines whether 0-RTT should be accepted. This will be passed the
/// value of the `extra` argument that was passed to `Connection::send_ticket` to see if it is
/// OK.
/// * `cid_generator` is responsible for generating connection IDs and parsing them; connection
/// IDs produced by the manager cannot be zero-length.
/// # Errors
/// When address validation state cannot be created.
pub fn new(
now: Instant,
certs: &[impl AsRef<str>],
protocols: &[impl AsRef<str>],
anti_replay: AntiReplay,
zero_rtt_checker: Box<dyn ZeroRttChecker>,
cid_generator: Rc<RefCell<dyn ConnectionIdGenerator>>,
conn_params: ConnectionParameters,
) -> Res<Self> {
let validation = AddressValidation::new(now, ValidateAddress::Never)?;
Ok(Self {
certs: certs.iter().map(|x| String::from(x.as_ref())).collect(),
protocols: protocols.iter().map(|x| String::from(x.as_ref())).collect(),
ciphers: Vec::new(),
anti_replay,
zero_rtt_checker: ServerZeroRttChecker::new(zero_rtt_checker),
cid_generator,
conn_params,
connections: Vec::new(),
address_validation: Rc::new(RefCell::new(validation)),
qlog_dir: None,
ech_config: None,
})
}
/// Set or clear directory to create logs of connection events in QLOG format.
pub fn set_qlog_dir(&mut self, dir: Option<PathBuf>) {
self.qlog_dir = dir;
}
/// Set the policy for address validation.
pub fn set_validation(&self, v: ValidateAddress) {
self.address_validation.borrow_mut().set_validation(v);
}
/// Set the cipher suites that should be used. Set an empty value to use
/// default values.
pub fn set_ciphers(&mut self, ciphers: impl AsRef<[Cipher]>) {
self.ciphers = Vec::from(ciphers.as_ref());
}
/// # Errors
/// When the configuration is invalid.
pub fn enable_ech(
&mut self,
config: u8,
public_name: &str,
sk: &PrivateKey,
pk: &PublicKey,
) -> Res<()> {
self.ech_config = Some(EchConfig::new(config, public_name, sk, pk)?);
Ok(())
}
#[must_use]
pub fn ech_config(&self) -> &[u8] {
self.ech_config.as_ref().map_or(&[], |cfg| &cfg.encoded)
}
fn handle_initial(
&mut self,
initial: InitialDetails,
dgram: Datagram<impl AsRef<[u8]>>,
now: Instant,
) -> Output {
qdebug!([self], "Handle initial");
let res = self
.address_validation
.borrow()
.validate(&initial.token, dgram.source(), now);
match res {
AddressValidationResult::Invalid => Output::None,
AddressValidationResult::Pass => self.accept_connection(initial, dgram, None, now),
AddressValidationResult::ValidRetry(orig_dcid) => {
self.accept_connection(initial, dgram, Some(orig_dcid), now)
}
AddressValidationResult::Validate => {
qinfo!([self], "Send retry for {:?}", initial.dst_cid);
let res = self.address_validation.borrow().generate_retry_token(
&initial.dst_cid,
dgram.source(),
now,
);
let Ok(token) = res else {
qerror!([self], "unable to generate token, dropping packet");
return Output::None;
};
if let Some(new_dcid) = self.cid_generator.borrow_mut().generate_cid() {
let packet = PacketBuilder::retry(
initial.version,
&initial.src_cid,
&new_dcid,
&token,
&initial.dst_cid,
);
packet.map_or_else(
|_| {
qerror!([self], "unable to encode retry, dropping packet");
Output::None
},
|p| {
Output::Datagram(Datagram::new(
dgram.destination(),
dgram.source(),
dgram.tos(),
p,
))
},
)
} else {
qerror!([self], "no connection ID for retry, dropping packet");
Output::None
}
}
}
}
fn create_qlog_trace(&self, odcid: ConnectionIdRef<'_>) -> NeqoQlog {
self.qlog_dir
.as_ref()
.map_or_else(NeqoQlog::disabled, |qlog_dir| {
NeqoQlog::enabled_with_file(
qlog_dir.clone(),
Role::Server,
Some("Neqo server qlog".to_string()),
Some("Neqo server qlog".to_string()),
odcid,
)
.unwrap_or_else(|e| {
qerror!("failed to create NeqoQlog: {}", e);
NeqoQlog::disabled()
})
})
}
fn setup_connection(
&self,
c: &mut Connection,
initial: InitialDetails,
orig_dcid: Option<ConnectionId>,
) {
let zcheck = self.zero_rtt_checker.clone();
if c.server_enable_0rtt(&self.anti_replay, zcheck).is_err() {
qwarn!([self], "Unable to enable 0-RTT");
}
if let Some(odcid) = &orig_dcid {
// There was a retry, so set the connection IDs for.
c.set_retry_cids(odcid, initial.src_cid, &initial.dst_cid);
}
c.set_validation(&self.address_validation);
c.set_qlog(self.create_qlog_trace(orig_dcid.unwrap_or(initial.dst_cid).as_cid_ref()));
if let Some(cfg) = &self.ech_config {
if c.server_enable_ech(cfg.config, &cfg.public_name, &cfg.sk, &cfg.pk)
.is_err()
{
qwarn!([self], "Unable to enable ECH");
}
}
}
fn accept_connection(
&mut self,
initial: InitialDetails,
dgram: Datagram<impl AsRef<[u8]>>,
orig_dcid: Option<ConnectionId>,
now: Instant,
) -> Output {
qinfo!(
[self],
"Accept connection {:?}",
orig_dcid.as_ref().unwrap_or(&initial.dst_cid)
);
// The internal connection ID manager that we use is not used directly.
// Instead, wrap it so that we can save connection IDs.
let mut params = self.conn_params.clone();
params.get_versions_mut().set_initial(initial.version);
let sconn = Connection::new_server(
&self.certs,
&self.protocols,
Rc::clone(&self.cid_generator),
params,
);
match sconn {
Ok(mut c) => {
self.setup_connection(&mut c, initial, orig_dcid);
let out = c.process(Some(dgram), now);
self.connections.push(Rc::new(RefCell::new(c)));
out
}
Err(e) => {
qwarn!([self], "Unable to create connection");
if e == crate::Error::VersionNegotiation {
crate::qlog::server_version_information_failed(
&self.create_qlog_trace(orig_dcid.unwrap_or(initial.dst_cid).as_cid_ref()),
self.conn_params.get_versions().all(),
initial.version.wire_version(),
now,
);
}
Output::None
}
}
}
fn process_input(&mut self, dgram: Datagram<impl AsRef<[u8]>>, now: Instant) -> Output {
qtrace!("Process datagram: {}", hex(&dgram[..]));
// This is only looking at the first packet header in the datagram.
// All packets in the datagram are routed to the same connection.
let res = PublicPacket::decode(&dgram[..], self.cid_generator.borrow().as_decoder());
let Ok((packet, _remainder)) = res else {
qtrace!([self], "Discarding {:?}", dgram);
return Output::None;
};
// Finding an existing connection. Should be the most common case.
if let Some(c) = self
.connections
.iter_mut()
.find(|c| c.borrow().is_valid_local_cid(packet.dcid()))
{
return c.borrow_mut().process(Some(dgram), now);
}
if packet.packet_type() == PacketType::Short {
// TODO send a stateless reset here.
qtrace!([self], "Short header packet for an unknown connection");
return Output::None;
}
if packet.packet_type() == PacketType::OtherVersion
|| (packet.packet_type() == PacketType::Initial
&& !self
.conn_params
.get_versions()
.all()
.contains(&packet.version().unwrap()))
{
if dgram.len() < MIN_INITIAL_PACKET_SIZE {
qdebug!([self], "Unsupported version: too short");
return Output::None;
}
qdebug!([self], "Unsupported version: {:x}", packet.wire_version());
let vn = PacketBuilder::version_negotiation(
&packet.scid()[..],
&packet.dcid()[..],
packet.wire_version(),
self.conn_params.get_versions().all(),
);
crate::qlog::server_version_information_failed(
&self.create_qlog_trace(packet.dcid()),
self.conn_params.get_versions().all(),
packet.wire_version(),
now,
);
return Output::Datagram(Datagram::new(
dgram.destination(),
dgram.source(),
dgram.tos(),
vn,
));
}
match packet.packet_type() {
PacketType::Initial => {
if dgram.len() < MIN_INITIAL_PACKET_SIZE {
qdebug!([self], "Drop initial: too short");
return Output::None;
}
// Copy values from `packet` because they are currently still borrowing from
// `dgram`.
let initial = InitialDetails::new(&packet);
self.handle_initial(initial, dgram, now)
}
PacketType::ZeroRtt => {
let dcid = ConnectionId::from(packet.dcid());
qdebug!([self], "Dropping 0-RTT for unknown connection {}", dcid);
Output::None
}
PacketType::OtherVersion => unreachable!(),
_ => {
qtrace!([self], "Not an initial packet");
Output::None
}
}
}
/// Iterate through the pending connections looking for any that might want
/// to send a datagram. Stop at the first one that does.
fn process_next_output(&mut self, now: Instant) -> Output {
let mut callback = None;
for connection in &mut self.connections {
match connection.borrow_mut().process_output(now) {
Output::None => {}
d @ Output::Datagram(_) => return d,
Output::Callback(next) => match callback {
Some(previous) => callback = Some(min(previous, next)),
None => callback = Some(next),
},
}
}
callback.map_or(Output::None, Output::Callback)
}
/// Short-hand for [`Server::process`] without an input datagram.
#[must_use]
pub fn process_output(&mut self, now: Instant) -> Output {
self.process(None::<Datagram>, now)
}
#[must_use]
pub fn process(&mut self, dgram: Option<Datagram<impl AsRef<[u8]>>>, now: Instant) -> Output {
let out = dgram
.map_or(Output::None, |d| self.process_input(d, now))
.or_else(|| self.process_next_output(now));
// Clean-up closed connections.
self.connections
.retain(|c| !matches!(c.borrow().state(), State::Closed(_)));
out
}
/// This lists the connections that have received new events
/// as a result of calling `process()`.
// `ActiveConnectionRef` `Hash` implementation doesn’t access any of the interior mutable types.
#[allow(clippy::mutable_key_type)]
#[must_use]
pub fn active_connections(&self) -> HashSet<ConnectionRef> {
self.connections
.iter()
.filter(|c| c.borrow().has_events())
.map(|c| ConnectionRef { c: Rc::clone(c) })
.collect()
}
/// Whether any connections have received new events as a result of calling
/// `process()`.
#[must_use]
pub fn has_active_connections(&self) -> bool {
self.connections.iter().any(|c| c.borrow().has_events())
}
}
#[derive(Clone, Debug)]
pub struct ConnectionRef {
c: Rc<RefCell<Connection>>,
}
impl ConnectionRef {
#[must_use]
pub fn borrow(&self) -> impl Deref<Target = Connection> + '_ {
self.c.borrow()
}
#[must_use]
pub fn borrow_mut(&self) -> impl DerefMut<Target = Connection> + '_ {
self.c.borrow_mut()
}
#[must_use]
pub fn connection(&self) -> Rc<RefCell<Connection>> {
Rc::clone(&self.c)
}
}
impl std::hash::Hash for ConnectionRef {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
let ptr: *const _ = self.c.as_ref();
ptr.hash(state);
}
}
impl PartialEq for ConnectionRef {
fn eq(&self, other: &Self) -> bool {
Rc::ptr_eq(&self.c, &other.c)
}
}
impl Eq for ConnectionRef {}
impl ::std::fmt::Display for Server {
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, "Server")
}
}