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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
use crate::{
callbacks::*,
enums::*,
error::{Error, Fallible},
security,
};
use core::{convert::TryInto, ptr::NonNull};
use s2n_tls_sys::*;
use std::{
ffi::{c_void, CString},
path::Path,
pin::Pin,
sync::atomic::{AtomicUsize, Ordering},
task::Poll,
time::{Duration, SystemTime},
};
#[derive(Debug, PartialEq)]
pub struct Config(NonNull<s2n_config>);
/// # Safety
///
/// Safety: s2n_config objects can be sent across threads
unsafe impl Send for Config {}
/// # Safety
///
/// Safety: All C methods that mutate the s2n_config are wrapped
/// in Rust methods that require a mutable reference.
unsafe impl Sync for Config {}
impl Config {
/// Returns a Config object with pre-defined defaults.
///
/// Use the [`Builder`] if custom configuration is desired.
pub fn new() -> Self {
Self::default()
}
/// Returns a Builder which can be used to configure the Config
pub fn builder() -> Builder {
Builder::default()
}
/// # Safety
///
/// This config _MUST_ have been initialized with a [`Builder`].
/// Additionally, this does NOT increment the config reference count,
/// so consider cloning the result if the source pointer is still
/// valid and usable afterwards.
pub(crate) unsafe fn from_raw(config: NonNull<s2n_config>) -> Self {
let config = Self(config);
// Check if the context can be retrieved.
// If it can't, this is not a valid config.
config.context();
config
}
pub(crate) fn as_mut_ptr(&mut self) -> *mut s2n_config {
self.0.as_ptr()
}
/// Retrieve a reference to the [`Context`] stored on the config.
pub(crate) fn context(&self) -> &Context {
let mut ctx = core::ptr::null_mut();
unsafe {
s2n_config_get_ctx(self.0.as_ptr(), &mut ctx)
.into_result()
.unwrap();
&*(ctx as *const Context)
}
}
/// Retrieve a mutable reference to the [`Context`] stored on the config.
pub(crate) fn context_mut(&mut self) -> &mut Context {
let mut ctx = core::ptr::null_mut();
unsafe {
s2n_config_get_ctx(self.as_mut_ptr(), &mut ctx)
.into_result()
.unwrap();
&mut *(ctx as *mut Context)
}
}
#[cfg(test)]
/// Get the refcount associated with the config
pub fn test_get_refcount(&self) -> Result<usize, Error> {
let context = self.context();
Ok(context.refcount.load(Ordering::SeqCst))
}
}
impl Default for Config {
fn default() -> Self {
Builder::new().build().unwrap()
}
}
impl Clone for Config {
fn clone(&self) -> Self {
let context = self.context();
// Safety
//
// Using a relaxed ordering is alright here, as knowledge of the
// original reference prevents other threads from erroneously deleting
// the object.
// https://github.com/rust-lang/rust/blob/e012a191d768adeda1ee36a99ef8b92d51920154/library/alloc/src/sync.rs#L1329
let _count = context.refcount.fetch_add(1, Ordering::Relaxed);
Self(self.0)
}
}
impl Drop for Config {
fn drop(&mut self) {
let context = self.context_mut();
let count = context.refcount.fetch_sub(1, Ordering::Release);
debug_assert!(count > 0, "refcount should not drop below 1 instance");
// only free the config if this is the last instance
if count != 1 {
return;
}
// Safety
//
// The use of Ordering and fence mirrors the `Arc` implementation in
// the standard library.
//
// This fence is needed to prevent reordering of use of the data and
// deletion of the data. Because it is marked `Release`, the decreasing
// of the reference count synchronizes with this `Acquire` fence. This
// means that use of the data happens before decreasing the reference
// count, which happens before this fence, which happens before the
// deletion of the data.
// https://github.com/rust-lang/rust/blob/e012a191d768adeda1ee36a99ef8b92d51920154/library/alloc/src/sync.rs#L1637
std::sync::atomic::fence(Ordering::Acquire);
unsafe {
// This is the last instance so free the context.
let context = Box::from_raw(context);
drop(context);
let _ = s2n_config_free(self.0.as_ptr()).into_result();
}
}
}
pub struct Builder {
config: Config,
load_system_certs: bool,
enable_ocsp: bool,
}
impl Builder {
pub fn new() -> Self {
crate::init::init();
let config = unsafe { s2n_config_new_minimal().into_result() }.unwrap();
let context = Box::<Context>::default();
let context = Box::into_raw(context) as *mut c_void;
unsafe {
s2n_config_set_ctx(config.as_ptr(), context)
.into_result()
.unwrap();
// The client hello callback originally did not support async operations,
// so defaults to blocking mode for backwards compatibility with old integrations.
// But these bindings use a polling model, so assume non-blocking mode.
s2n_config_set_client_hello_cb_mode(
config.as_ptr(),
s2n_client_hello_cb_mode::NONBLOCKING,
)
.into_result()
.unwrap();
}
Self {
config: Config(config),
load_system_certs: true,
enable_ocsp: false,
}
}
pub fn set_alert_behavior(&mut self, value: AlertBehavior) -> Result<&mut Self, Error> {
unsafe { s2n_config_set_alert_behavior(self.as_mut_ptr(), value.into()).into_result() }?;
Ok(self)
}
pub fn set_security_policy(&mut self, policy: &security::Policy) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_cipher_preferences(self.as_mut_ptr(), policy.as_cstr().as_ptr())
.into_result()
}?;
Ok(self)
}
/// sets the application protocol preferences on an s2n_config object.
///
/// protocols is a list in order of preference, with most preferred protocol first,
/// and of length protocol_count. When acting as a client the protocol list is
/// included in the Client Hello message as the ALPN extension. As a server, the
/// list is used to negotiate a mutual application protocol with the client. After
/// the negotiation for the connection has completed, the agreed upon protocol can
/// be retrieved with s2n_get_application_protocol
pub fn set_application_protocol_preference<P: IntoIterator<Item = I>, I: AsRef<[u8]>>(
&mut self,
protocols: P,
) -> Result<&mut Self, Error> {
// reset the list
unsafe {
s2n_config_set_protocol_preferences(self.as_mut_ptr(), core::ptr::null(), 0)
.into_result()
}?;
for protocol in protocols {
self.append_application_protocol_preference(protocol.as_ref())?;
}
Ok(self)
}
pub fn append_application_protocol_preference(
&mut self,
protocol: &[u8],
) -> Result<&mut Self, Error> {
unsafe {
s2n_config_append_protocol_preference(
self.as_mut_ptr(),
protocol.as_ptr(),
protocol
.len()
.try_into()
.map_err(|_| Error::INVALID_INPUT)?,
)
.into_result()
}?;
Ok(self)
}
/// Turns off x509 verification
///
/// # Safety
/// This functionality will weaken the security of the connections. As such, it should only
/// be used in development environments where obtaining a valid certificate would not be possible.
pub unsafe fn disable_x509_verification(&mut self) -> Result<&mut Self, Error> {
s2n_config_disable_x509_verification(self.as_mut_ptr()).into_result()?;
Ok(self)
}
pub fn add_dhparams(&mut self, pem: &[u8]) -> Result<&mut Self, Error> {
let cstring = CString::new(pem).map_err(|_| Error::INVALID_INPUT)?;
unsafe { s2n_config_add_dhparams(self.as_mut_ptr(), cstring.as_ptr()).into_result() }?;
Ok(self)
}
pub fn load_pem(&mut self, certificate: &[u8], private_key: &[u8]) -> Result<&mut Self, Error> {
let certificate = CString::new(certificate).map_err(|_| Error::INVALID_INPUT)?;
let private_key = CString::new(private_key).map_err(|_| Error::INVALID_INPUT)?;
unsafe {
s2n_config_add_cert_chain_and_key(
self.as_mut_ptr(),
certificate.as_ptr(),
private_key.as_ptr(),
)
.into_result()
}?;
Ok(self)
}
pub fn load_public_pem(&mut self, certificate: &[u8]) -> Result<&mut Self, Error> {
let size: u32 = certificate
.len()
.try_into()
.map_err(|_| Error::INVALID_INPUT)?;
let certificate = certificate.as_ptr() as *mut u8;
unsafe { s2n_config_add_cert_chain(self.as_mut_ptr(), certificate, size) }.into_result()?;
Ok(self)
}
pub fn trust_pem(&mut self, certificate: &[u8]) -> Result<&mut Self, Error> {
let certificate = CString::new(certificate).map_err(|_| Error::INVALID_INPUT)?;
unsafe {
s2n_config_add_pem_to_trust_store(self.as_mut_ptr(), certificate.as_ptr()).into_result()
}?;
Ok(self)
}
/// Adds to the trust store from a CA file or directory containing trusted certificates.
///
/// NOTE: This function is equivalent to `s2n_config_set_verification_ca_location` except it does
/// not automatically enable the client to request OCSP stapling from the server.
pub fn trust_location(
&mut self,
file: Option<&Path>,
dir: Option<&Path>,
) -> Result<&mut Self, Error> {
fn to_cstr(input: Option<&Path>) -> Result<Option<CString>, Error> {
Ok(match input {
Some(input) => {
let string = input.to_str().ok_or(Error::INVALID_INPUT)?;
let cstring = CString::new(string).map_err(|_| Error::INVALID_INPUT)?;
Some(cstring)
}
None => None,
})
}
let file_cstr = to_cstr(file)?;
let file_ptr = file_cstr
.as_ref()
.map(|f| f.as_ptr())
.unwrap_or(core::ptr::null());
let dir_cstr = to_cstr(dir)?;
let dir_ptr = dir_cstr
.as_ref()
.map(|f| f.as_ptr())
.unwrap_or(core::ptr::null());
unsafe {
s2n_config_set_verification_ca_location(self.as_mut_ptr(), file_ptr, dir_ptr)
.into_result()
}?;
// If OCSP has not been explicitly requested, turn off OCSP. This is to prevent this function from
// automatically enabling `OCSP` due to the legacy behavior of `s2n_config_set_verification_ca_location`
if !self.enable_ocsp {
unsafe {
s2n_config_set_status_request_type(self.as_mut_ptr(), s2n_status_request_type::NONE)
.into_result()?
};
}
Ok(self)
}
/// Sets whether or not default system certificates will be loaded into the trust store.
///
/// Set to false for increased performance if system certificates are not needed during
/// certificate validation.
pub fn with_system_certs(&mut self, load_system_certs: bool) -> Result<&mut Self, Error> {
self.load_system_certs = load_system_certs;
Ok(self)
}
pub fn wipe_trust_store(&mut self) -> Result<&mut Self, Error> {
unsafe { s2n_config_wipe_trust_store(self.as_mut_ptr()).into_result()? };
Ok(self)
}
/// Sets whether or not a client certificate should be required to complete the TLS connection.
///
/// See the [Usage Guide](https://github.com/aws/s2n-tls/blob/main/docs/USAGE-GUIDE.md#client-auth-related-calls) for more details.
pub fn set_client_auth_type(&mut self, auth_type: ClientAuthType) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_client_auth_type(self.as_mut_ptr(), auth_type.into()).into_result()
}?;
Ok(self)
}
/// Clients will request OCSP stapling from the server.
pub fn enable_ocsp(&mut self) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_status_request_type(self.as_mut_ptr(), s2n_status_request_type::OCSP)
.into_result()
}?;
self.enable_ocsp = true;
Ok(self)
}
/// Sets the OCSP data for the default certificate chain associated with the Config.
///
/// Servers will send the data in response to OCSP stapling requests from clients.
//
// NOTE: this modifies a certificate chain, NOT the Config itself. This is currently safe
// because the certificate chain is set with s2n_config_add_cert_chain_and_key, which
// creates a new certificate chain only accessible by the given config. It will
// NOT be safe when we add support for the newer s2n_config_add_cert_chain_and_key_to_store API,
// which allows certificate chains to be shared across configs.
// In that case, we'll need additional guard rails either in these bindings or in the underlying C.
pub fn set_ocsp_data(&mut self, data: &[u8]) -> Result<&mut Self, Error> {
let size: u32 = data.len().try_into().map_err(|_| Error::INVALID_INPUT)?;
unsafe {
s2n_config_set_extension_data(
self.as_mut_ptr(),
s2n_tls_extension_type::OCSP_STAPLING,
data.as_ptr(),
size,
)
.into_result()
}?;
self.enable_ocsp()
}
/// Sets the callback to use for verifying that a hostname from an X.509 certificate is
/// trusted.
///
/// The callback may be called more than once during certificate validation as each SAN on
/// the certificate will be checked.
///
/// Corresponds to the underlying C API
/// [s2n_config_set_verify_host_callback](https://aws.github.io/s2n-tls/doxygen/s2n_8h.html).
pub fn set_verify_host_callback<T: 'static + VerifyHostNameCallback>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
unsafe extern "C" fn verify_host_cb_fn(
host_name: *const ::libc::c_char,
host_name_len: usize,
context: *mut ::libc::c_void,
) -> u8 {
let context = &mut *(context as *mut Context);
let handler = context.verify_host_callback.as_mut().unwrap();
verify_host(host_name, host_name_len, handler)
}
self.config.context_mut().verify_host_callback = Some(Box::new(handler));
unsafe {
s2n_config_set_verify_host_callback(
self.as_mut_ptr(),
Some(verify_host_cb_fn),
self.config.context_mut() as *mut Context as *mut c_void,
)
.into_result()?;
}
Ok(self)
}
/// # Safety
/// THIS SHOULD BE USED FOR DEBUGGING PURPOSES ONLY!
/// The `context` pointer must live at least as long as the config
pub unsafe fn set_key_log_callback(
&mut self,
callback: s2n_key_log_fn,
context: *mut core::ffi::c_void,
) -> Result<&mut Self, Error> {
s2n_config_set_key_log_cb(self.as_mut_ptr(), callback, context).into_result()?;
Ok(self)
}
pub fn set_max_cert_chain_depth(&mut self, depth: u16) -> Result<&mut Self, Error> {
unsafe { s2n_config_set_max_cert_chain_depth(self.as_mut_ptr(), depth).into_result() }?;
Ok(self)
}
pub fn set_send_buffer_size(&mut self, size: u32) -> Result<&mut Self, Error> {
unsafe { s2n_config_set_send_buffer_size(self.as_mut_ptr(), size).into_result() }?;
Ok(self)
}
/// Set a custom callback function which is run after parsing the client hello.
pub fn set_client_hello_callback<T: 'static + ClientHelloCallback>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
unsafe extern "C" fn client_hello_cb(
connection_ptr: *mut s2n_connection,
_context: *mut core::ffi::c_void,
) -> libc::c_int {
with_context(connection_ptr, |conn, context| {
let callback = context.client_hello_callback.as_ref();
let future = callback
.map(|c| c.on_client_hello(conn))
.unwrap_or(Ok(None));
AsyncCallback::trigger_client_hello_cb(future, conn)
})
.into()
}
let handler = Box::new(handler);
let context = self.config.context_mut();
context.client_hello_callback = Some(handler);
unsafe {
s2n_config_set_client_hello_cb(
self.as_mut_ptr(),
Some(client_hello_cb),
core::ptr::null_mut(),
)
.into_result()?;
}
Ok(self)
}
pub fn set_connection_initializer<T: 'static + ConnectionInitializer>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
// Store callback in config context
let handler = Box::new(handler);
let context = self.config.context_mut();
context.connection_initializer = Some(handler);
Ok(self)
}
/// Sets a custom callback which provides access to session tickets when they arrive
pub fn set_session_ticket_callback<T: 'static + SessionTicketCallback>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
// enable session tickets automatically
self.enable_session_tickets(true)?;
// Define C callback function that can be set on the s2n_config struct
unsafe extern "C" fn session_ticket_cb(
conn_ptr: *mut s2n_connection,
_context: *mut ::libc::c_void,
session_ticket: *mut s2n_session_ticket,
) -> libc::c_int {
let session_ticket = SessionTicket::from_ptr(&*session_ticket);
with_context(conn_ptr, |conn, context| {
let callback = context.session_ticket_callback.as_ref();
callback.map(|c| c.on_session_ticket(conn, session_ticket))
});
CallbackResult::Success.into()
}
// Store callback in context
let handler = Box::new(handler);
let context = self.config.context_mut();
context.session_ticket_callback = Some(handler);
unsafe {
s2n_config_set_session_ticket_cb(
self.as_mut_ptr(),
Some(session_ticket_cb),
self.config.context_mut() as *mut Context as *mut c_void,
)
.into_result()
}?;
Ok(self)
}
/// Set a callback function triggered by operations requiring the private key.
///
/// See https://github.com/aws/s2n-tls/blob/main/docs/USAGE-GUIDE.md#private-key-operation-related-calls
pub fn set_private_key_callback<T: 'static + PrivateKeyCallback>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
unsafe extern "C" fn private_key_cb(
conn_ptr: *mut s2n_connection,
op_ptr: *mut s2n_async_pkey_op,
) -> libc::c_int {
with_context(conn_ptr, |conn, context| {
let state = PrivateKeyOperation::try_from_cb(conn, op_ptr);
let callback = context.private_key_callback.as_ref();
let future_result = state.and_then(|state| {
callback.map_or(Ok(None), |callback| callback.handle_operation(conn, state))
});
AsyncCallback::trigger(future_result, conn)
})
.into()
}
let handler = Box::new(handler);
let context = self.config.context_mut();
context.private_key_callback = Some(handler);
unsafe {
s2n_config_set_async_pkey_callback(self.as_mut_ptr(), Some(private_key_cb))
.into_result()?;
}
Ok(self)
}
/// Set a callback function that will be used to get the system time.
///
/// The wall clock time is the best-guess at the real time, measured since the epoch.
/// Unlike monotonic time, it CAN move backwards.
/// It is used by s2n-tls for timestamps.
pub fn set_wall_clock<T: 'static + WallClock>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
unsafe extern "C" fn clock_cb(
context: *mut ::libc::c_void,
time_in_nanos: *mut u64,
) -> libc::c_int {
let context = &mut *(context as *mut Context);
if let Some(handler) = context.wall_clock.as_mut() {
if let Ok(nanos) = handler.get_time_since_epoch().as_nanos().try_into() {
*time_in_nanos = nanos;
return CallbackResult::Success.into();
}
}
CallbackResult::Failure.into()
}
let handler = Box::new(handler);
let context = self.config.context_mut();
context.wall_clock = Some(handler);
unsafe {
s2n_config_set_wall_clock(
self.as_mut_ptr(),
Some(clock_cb),
self.config.context_mut() as *mut _ as *mut c_void,
)
.into_result()?;
}
Ok(self)
}
/// Set a callback function that will be used to get the monotonic time.
///
/// The monotonic time is the time since an arbitrary, unspecified point.
/// Unlike wall clock time, it MUST never move backwards.
/// It is used by s2n-tls for timers.
pub fn set_monotonic_clock<T: 'static + MonotonicClock>(
&mut self,
handler: T,
) -> Result<&mut Self, Error> {
unsafe extern "C" fn clock_cb(
context: *mut ::libc::c_void,
time_in_nanos: *mut u64,
) -> libc::c_int {
let context = &mut *(context as *mut Context);
if let Some(handler) = context.monotonic_clock.as_mut() {
if let Ok(nanos) = handler.get_time().as_nanos().try_into() {
*time_in_nanos = nanos;
return CallbackResult::Success.into();
}
}
CallbackResult::Failure.into()
}
let handler = Box::new(handler);
let context = self.config.context_mut();
context.monotonic_clock = Some(handler);
unsafe {
s2n_config_set_monotonic_clock(
self.as_mut_ptr(),
Some(clock_cb),
self.config.context_mut() as *mut _ as *mut c_void,
)
.into_result()?;
}
Ok(self)
}
/// Enable negotiating session tickets in a TLS connection
pub fn enable_session_tickets(&mut self, enable: bool) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_session_tickets_onoff(self.as_mut_ptr(), enable.into()).into_result()
}?;
Ok(self)
}
/// Adds a key which will be used to encrypt and decrypt session tickets. The intro_time parameter is time since
/// the Unix epoch (Midnight, January 1st, 1970). The key must be at least 16 bytes.
pub fn add_session_ticket_key(
&mut self,
key_name: &[u8],
key: &[u8],
intro_time: SystemTime,
) -> Result<&mut Self, Error> {
let key_name_len: u32 = key_name
.len()
.try_into()
.map_err(|_| Error::INVALID_INPUT)?;
let key_len: u32 = key.len().try_into().map_err(|_| Error::INVALID_INPUT)?;
let intro_time = intro_time
.duration_since(std::time::UNIX_EPOCH)
.map_err(|_| Error::INVALID_INPUT)?;
// Ticket keys should be at least 128 bits in strength
// https://www.rfc-editor.org/rfc/rfc5077#section-5.5
if key_len < 16 {
return Err(Error::INVALID_INPUT);
}
self.enable_session_tickets(true)?;
unsafe {
s2n_config_add_ticket_crypto_key(
self.as_mut_ptr(),
key_name.as_ptr(),
key_name_len,
// s2n-tls doesn't mutate key, it's just mut for easier use with stuffers and blobs
key.as_ptr() as *mut u8,
key_len,
intro_time.as_secs(),
)
.into_result()
}?;
Ok(self)
}
// Sets how long a session ticket key will be able to be used for both encryption
// and decryption of tickets
pub fn set_ticket_key_encrypt_decrypt_lifetime(
&mut self,
lifetime: Duration,
) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_ticket_encrypt_decrypt_key_lifetime(
self.as_mut_ptr(),
lifetime.as_secs(),
)
.into_result()
}?;
Ok(self)
}
// Sets how long a session ticket key will be able to be used for only decryption
pub fn set_ticket_key_decrypt_lifetime(
&mut self,
lifetime: Duration,
) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_ticket_decrypt_key_lifetime(self.as_mut_ptr(), lifetime.as_secs())
.into_result()
}?;
Ok(self)
}
/// Sets the expected connection serialization version. Must be set
/// before serializing the connection.
pub fn set_serialization_version(
&mut self,
version: SerializationVersion,
) -> Result<&mut Self, Error> {
unsafe {
s2n_config_set_serialization_version(self.as_mut_ptr(), version.into()).into_result()
}?;
Ok(self)
}
pub fn build(mut self) -> Result<Config, Error> {
if self.load_system_certs {
unsafe {
s2n_config_load_system_certs(self.as_mut_ptr()).into_result()?;
}
}
Ok(self.config)
}
fn as_mut_ptr(&mut self) -> *mut s2n_config {
self.config.as_mut_ptr()
}
}
#[cfg(feature = "quic")]
impl Builder {
pub fn enable_quic(&mut self) -> Result<&mut Self, Error> {
unsafe { s2n_tls_sys::s2n_config_enable_quic(self.as_mut_ptr()).into_result() }?;
Ok(self)
}
}
impl Default for Builder {
fn default() -> Self {
Self::new()
}
}
pub(crate) struct Context {
refcount: AtomicUsize,
pub(crate) client_hello_callback: Option<Box<dyn ClientHelloCallback>>,
pub(crate) private_key_callback: Option<Box<dyn PrivateKeyCallback>>,
pub(crate) verify_host_callback: Option<Box<dyn VerifyHostNameCallback>>,
pub(crate) session_ticket_callback: Option<Box<dyn SessionTicketCallback>>,
pub(crate) connection_initializer: Option<Box<dyn ConnectionInitializer>>,
pub(crate) wall_clock: Option<Box<dyn WallClock>>,
pub(crate) monotonic_clock: Option<Box<dyn MonotonicClock>>,
}
impl Default for Context {
fn default() -> Self {
// The AtomicUsize is used to manually track the reference count of the Config.
// This mechanism is used to track when the Config object should be freed.
let refcount = AtomicUsize::new(1);
Self {
refcount,
client_hello_callback: None,
private_key_callback: None,
verify_host_callback: None,
session_ticket_callback: None,
connection_initializer: None,
wall_clock: None,
monotonic_clock: None,
}
}
}
/// A trait executed asynchronously before a new connection negotiates TLS.
///
/// Used for dynamic configuration of a specific connection.
///
/// # Safety: This trait is polled to completion at the beginning of the
/// [connection::poll_negotiate](`crate::connection::poll_negotiate()`) function.
/// Therefore, negotiation of the TLS connection will not begin until the Future has completed.
pub trait ConnectionInitializer: 'static + Send + Sync {
/// The application can return an `Ok(None)` to resolve the callback
/// synchronously or return an `Ok(Some(ConnectionFuture))` if it wants to
/// run some asynchronous task before resolving the callback.
fn initialize_connection(
&self,
connection: &mut crate::connection::Connection,
) -> ConnectionFutureResult;
}
impl<A: ConnectionInitializer, B: ConnectionInitializer> ConnectionInitializer for (A, B) {
fn initialize_connection(
&self,
connection: &mut crate::connection::Connection,
) -> ConnectionFutureResult {
let a = self.0.initialize_connection(connection)?;
let b = self.1.initialize_connection(connection)?;
match (a, b) {
(None, None) => Ok(None),
(None, Some(fut)) => Ok(Some(fut)),
(Some(fut), None) => Ok(Some(fut)),
(Some(fut_a), Some(fut_b)) => Ok(Some(Box::pin(ConcurrentConnectionFuture::new([
fut_a, fut_b,
])))),
}
}
}
struct ConcurrentConnectionFuture<const N: usize> {
futures: [Option<Pin<Box<dyn ConnectionFuture>>>; N],
}
impl<const N: usize> ConcurrentConnectionFuture<N> {
fn new(futures: [Pin<Box<dyn ConnectionFuture>>; N]) -> Self {
let futures = futures.map(Some);
Self { futures }
}
}
impl<const N: usize> ConnectionFuture for ConcurrentConnectionFuture<N> {
fn poll(
mut self: std::pin::Pin<&mut Self>,
connection: &mut crate::connection::Connection,
ctx: &mut core::task::Context,
) -> std::task::Poll<Result<(), Error>> {
let mut is_pending = false;
for container in self.futures.iter_mut() {
if let Some(future) = container.as_mut() {
match future.as_mut().poll(connection, ctx) {
Poll::Ready(result) => {
result?;
*container = None;
}
Poll::Pending => is_pending = true,
}
}
}
if is_pending {
Poll::Pending
} else {
Poll::Ready(Ok(()))
}
}
}
#[cfg(test)]
mod tests {
use super::*;
// ensure the config context is send and sync
#[test]
fn context_send_sync_test() {
fn assert_send_sync<T: 'static + Send + Sync>() {}
assert_send_sync::<Context>();
}
}