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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.
#![allow(clippy::module_name_repetitions)]
use std::ops::Deref;
use neqo_common::{Decoder, Encoder};
use neqo_crypto::{ZeroRttCheckResult, ZeroRttChecker};
use crate::{Error, Http3Parameters, Res};
type SettingsType = u64;
/// Increment this version number if a new setting is added and that might
/// cause 0-RTT to be accepted where shouldn't be.
const SETTINGS_ZERO_RTT_VERSION: u64 = 1;
const SETTINGS_MAX_HEADER_LIST_SIZE: SettingsType = 0x6;
const SETTINGS_QPACK_MAX_TABLE_CAPACITY: SettingsType = 0x1;
const SETTINGS_QPACK_BLOCKED_STREAMS: SettingsType = 0x7;
const SETTINGS_ENABLE_WEB_TRANSPORT: SettingsType = 0x2b60_3742;
// draft-ietf-masque-h3-datagram-04.
// We also use this old value because the current web-platform test only supports
// this value.
const SETTINGS_H3_DATAGRAM_DRAFT04: SettingsType = 0x00ff_d277;
const SETTINGS_H3_DATAGRAM: SettingsType = 0x33;
pub const H3_RESERVED_SETTINGS: &[SettingsType] = &[0x2, 0x3, 0x4, 0x5];
#[derive(Clone, PartialEq, Eq, Debug, Copy)]
pub enum HSettingType {
MaxHeaderListSize,
MaxTableCapacity,
BlockedStreams,
EnableWebTransport,
EnableH3Datagram,
}
const fn hsetting_default(setting_type: HSettingType) -> u64 {
match setting_type {
HSettingType::MaxHeaderListSize => 1 << 62,
HSettingType::MaxTableCapacity
| HSettingType::BlockedStreams
| HSettingType::EnableWebTransport
| HSettingType::EnableH3Datagram => 0,
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct HSetting {
pub setting_type: HSettingType,
pub value: u64,
}
impl HSetting {
#[must_use]
pub const fn new(setting_type: HSettingType, value: u64) -> Self {
Self {
setting_type,
value,
}
}
}
#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct HSettings {
settings: Vec<HSetting>,
}
impl HSettings {
#[must_use]
pub fn new(settings: &[HSetting]) -> Self {
Self {
settings: settings.to_vec(),
}
}
#[must_use]
pub fn get(&self, setting: HSettingType) -> u64 {
self.settings
.iter()
.find(|s| s.setting_type == setting)
.map_or_else(|| hsetting_default(setting), |v| v.value)
}
pub fn encode_frame_contents(&self, enc: &mut Encoder) {
enc.encode_vvec_with(|enc_inner| {
for iter in &self.settings {
match iter.setting_type {
HSettingType::MaxHeaderListSize => {
enc_inner.encode_varint(SETTINGS_MAX_HEADER_LIST_SIZE);
enc_inner.encode_varint(iter.value);
}
HSettingType::MaxTableCapacity => {
enc_inner.encode_varint(SETTINGS_QPACK_MAX_TABLE_CAPACITY);
enc_inner.encode_varint(iter.value);
}
HSettingType::BlockedStreams => {
enc_inner.encode_varint(SETTINGS_QPACK_BLOCKED_STREAMS);
enc_inner.encode_varint(iter.value);
}
HSettingType::EnableWebTransport => {
enc_inner.encode_varint(SETTINGS_ENABLE_WEB_TRANSPORT);
enc_inner.encode_varint(iter.value);
}
HSettingType::EnableH3Datagram => {
if iter.value == 1 {
enc_inner.encode_varint(SETTINGS_H3_DATAGRAM_DRAFT04);
enc_inner.encode_varint(iter.value);
enc_inner.encode_varint(SETTINGS_H3_DATAGRAM);
enc_inner.encode_varint(iter.value);
}
}
}
}
});
}
/// # Errors
///
/// Returns an error if settings types are reserved of settings value are not permitted.
pub fn decode_frame_contents(&mut self, dec: &mut Decoder) -> Res<()> {
while dec.remaining() > 0 {
let t = dec.decode_varint();
let v = dec.decode_varint();
if let Some(settings_type) = t {
if H3_RESERVED_SETTINGS.contains(&settings_type) {
return Err(Error::HttpSettings);
}
}
match (t, v) {
(Some(SETTINGS_MAX_HEADER_LIST_SIZE), Some(value)) => self
.settings
.push(HSetting::new(HSettingType::MaxHeaderListSize, value)),
(Some(SETTINGS_QPACK_MAX_TABLE_CAPACITY), Some(value)) => self
.settings
.push(HSetting::new(HSettingType::MaxTableCapacity, value)),
(Some(SETTINGS_QPACK_BLOCKED_STREAMS), Some(value)) => self
.settings
.push(HSetting::new(HSettingType::BlockedStreams, value)),
(Some(SETTINGS_ENABLE_WEB_TRANSPORT), Some(value)) => {
if value > 1 {
return Err(Error::HttpSettings);
}
self.settings
.push(HSetting::new(HSettingType::EnableWebTransport, value));
}
(Some(SETTINGS_H3_DATAGRAM_DRAFT04), Some(value)) => {
if value > 1 {
return Err(Error::HttpSettings);
}
if !self
.settings
.iter()
.any(|s| s.setting_type == HSettingType::EnableH3Datagram)
{
self.settings
.push(HSetting::new(HSettingType::EnableH3Datagram, value));
}
}
(Some(SETTINGS_H3_DATAGRAM), Some(value)) => {
if value > 1 {
return Err(Error::HttpSettings);
}
if !self
.settings
.iter()
.any(|s| s.setting_type == HSettingType::EnableH3Datagram)
{
self.settings
.push(HSetting::new(HSettingType::EnableH3Datagram, value));
}
}
// other supported settings here
(Some(_), Some(_)) => {} // ignore unknown setting, it is fine.
_ => return Err(Error::NotEnoughData),
};
}
Ok(())
}
}
impl Deref for HSettings {
type Target = [HSetting];
fn deref(&self) -> &Self::Target {
&self.settings
}
}
impl From<&Http3Parameters> for HSettings {
fn from(conn_param: &Http3Parameters) -> Self {
Self {
settings: vec![
HSetting {
setting_type: HSettingType::MaxTableCapacity,
value: conn_param.get_max_table_size_decoder(),
},
HSetting {
setting_type: HSettingType::BlockedStreams,
value: u64::from(conn_param.get_max_blocked_streams()),
},
HSetting {
setting_type: HSettingType::EnableWebTransport,
value: u64::from(conn_param.get_webtransport()),
},
HSetting {
setting_type: HSettingType::EnableH3Datagram,
value: u64::from(conn_param.get_http3_datagram()),
},
],
}
}
}
#[derive(Debug)]
pub struct HttpZeroRttChecker {
settings: Http3Parameters,
}
impl HttpZeroRttChecker {
/// Right now we only have QPACK settings, so that is all this takes.
#[must_use]
pub const fn new(settings: Http3Parameters) -> Self {
Self { settings }
}
/// Save the settings that matter for 0-RTT.
#[must_use]
pub fn save(settings: &Http3Parameters) -> Vec<u8> {
let mut enc = Encoder::new();
enc.encode_varint(SETTINGS_ZERO_RTT_VERSION)
.encode_varint(SETTINGS_QPACK_MAX_TABLE_CAPACITY)
.encode_varint(settings.get_max_table_size_decoder())
.encode_varint(SETTINGS_QPACK_BLOCKED_STREAMS)
.encode_varint(settings.get_max_blocked_streams());
if settings.get_webtransport() {
enc.encode_varint(SETTINGS_ENABLE_WEB_TRANSPORT)
.encode_varint(true);
}
if settings.get_http3_datagram() {
enc.encode_varint(SETTINGS_H3_DATAGRAM).encode_varint(true);
}
enc.into()
}
}
impl ZeroRttChecker for HttpZeroRttChecker {
fn check(&self, token: &[u8]) -> ZeroRttCheckResult {
let mut dec = Decoder::from(token);
// Read and check the version.
if let Some(version) = dec.decode_varint() {
if version != SETTINGS_ZERO_RTT_VERSION {
return ZeroRttCheckResult::Reject;
}
} else {
return ZeroRttCheckResult::Fail;
}
// Now treat the rest as a settings frame.
let mut settings = HSettings::new(&[]);
if settings.decode_frame_contents(&mut dec).is_err() {
return ZeroRttCheckResult::Fail;
}
if settings.iter().all(|setting| match setting.setting_type {
HSettingType::BlockedStreams => {
u64::from(self.settings.get_max_blocked_streams()) >= setting.value
}
HSettingType::MaxTableCapacity => {
self.settings.get_max_table_size_decoder() >= setting.value
}
HSettingType::EnableWebTransport => {
if setting.value > 1 {
return false;
}
let value = setting.value == 1;
self.settings.get_webtransport() || !value
}
HSettingType::EnableH3Datagram => {
if setting.value > 1 {
return false;
}
let value = setting.value == 1;
self.settings.get_http3_datagram() || !value
}
HSettingType::MaxHeaderListSize => true,
}) {
ZeroRttCheckResult::Accept
} else {
ZeroRttCheckResult::Reject
}
}
}