1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
use std::convert::TryFrom;
use crate::proto::{frame, varint::VarInt};
/// Configures the HTTP/3 connection
#[derive(Debug, Clone, Copy)]
#[non_exhaustive]
pub struct Config {
/// Just like in HTTP/2, HTTP/3 also uses the concept of "grease"
/// to prevent potential interoperability issues in the future.
/// In HTTP/3, the concept of grease is used to ensure that the protocol can evolve
/// and accommodate future changes without breaking existing implementations.
pub(crate) send_grease: bool,
#[cfg(test)]
pub(crate) send_settings: bool,
/// HTTP/3 Settings
pub settings: Settings,
}
/// HTTP/3 Settings
#[derive(Debug, Clone, Copy)]
pub struct Settings {
/// The MAX_FIELD_SECTION_SIZE in HTTP/3 refers to the maximum size of the dynamic table used in HPACK compression.
/// HPACK is the compression algorithm used in HTTP/3 to reduce the size of the header fields in HTTP requests and responses.
/// In HTTP/3, the MAX_FIELD_SECTION_SIZE is set to 12.
/// This means that the dynamic table used for HPACK compression can have a maximum size of 2^12 bytes, which is 4KB.
pub(crate) max_field_section_size: u64,
/// https://datatracker.ietf.org/doc/html/draft-ietf-webtrans-http3/#section-3.1
/// Sets `SETTINGS_ENABLE_WEBTRANSPORT` if enabled
pub(crate) enable_webtransport: bool,
/// https://www.rfc-editor.org/info/rfc8441 defines an extended CONNECT method in Section 4,
/// enabled by the SETTINGS_ENABLE_CONNECT_PROTOCOL parameter.
/// That parameter is only defined for HTTP/2.
/// for extended CONNECT in HTTP/3; instead, the SETTINGS_ENABLE_WEBTRANSPORT setting implies that an endpoint supports extended CONNECT.
pub(crate) enable_extended_connect: bool,
/// Enable HTTP Datagrams, see https://datatracker.ietf.org/doc/rfc9297/ for details
pub(crate) enable_datagram: bool,
/// The maximum number of concurrent streams that can be opened by the peer.
pub(crate) max_webtransport_sessions: u64,
}
impl From<&frame::Settings> for Settings {
fn from(settings: &frame::Settings) -> Self {
let defaults: Self = Default::default();
Self {
max_field_section_size: settings
.get(frame::SettingId::MAX_HEADER_LIST_SIZE)
.unwrap_or(defaults.max_field_section_size),
enable_webtransport: settings
.get(frame::SettingId::ENABLE_WEBTRANSPORT)
.map(|value| value != 0)
.unwrap_or(defaults.enable_webtransport),
max_webtransport_sessions: settings
.get(frame::SettingId::WEBTRANSPORT_MAX_SESSIONS)
.unwrap_or(defaults.max_webtransport_sessions),
enable_datagram: settings
.get(frame::SettingId::H3_DATAGRAM)
.map(|value| value != 0)
.unwrap_or(defaults.enable_datagram),
enable_extended_connect: settings
.get(frame::SettingId::ENABLE_CONNECT_PROTOCOL)
.map(|value| value != 0)
.unwrap_or(defaults.enable_extended_connect),
}
}
}
impl TryFrom<Config> for frame::Settings {
type Error = frame::SettingsError;
fn try_from(value: Config) -> Result<Self, Self::Error> {
let mut settings = frame::Settings::default();
let Config {
send_grease,
#[cfg(test)]
send_settings: _,
settings:
Settings {
max_field_section_size,
enable_webtransport,
enable_extended_connect,
enable_datagram,
max_webtransport_sessions,
},
} = value;
if send_grease {
// Grease Settings (https://www.rfc-editor.org/rfc/rfc9114.html#name-defined-settings-parameters)
//= https://www.rfc-editor.org/rfc/rfc9114#section-7.2.4.1
//# Setting identifiers of the format 0x1f * N + 0x21 for non-negative
//# integer values of N are reserved to exercise the requirement that
//# unknown identifiers be ignored. Such settings have no defined
//# meaning. Endpoints SHOULD include at least one such setting in their
//# SETTINGS frame.
//= https://www.rfc-editor.org/rfc/rfc9114#section-7.2.4.1
//# Setting identifiers that were defined in [HTTP/2] where there is no
//# corresponding HTTP/3 setting have also been reserved
//# (Section 11.2.2). These reserved settings MUST NOT be sent, and
//# their receipt MUST be treated as a connection error of type
//# H3_SETTINGS_ERROR.
match settings.insert(frame::SettingId::grease(), 0) {
Ok(_) => (),
Err(_err) => {
#[cfg(feature = "tracing")]
tracing::warn!("Error when adding the grease Setting. Reason {}", _err);
}
}
}
settings.insert(
frame::SettingId::MAX_HEADER_LIST_SIZE,
max_field_section_size,
)?;
settings.insert(
frame::SettingId::ENABLE_CONNECT_PROTOCOL,
enable_extended_connect as u64,
)?;
settings.insert(
frame::SettingId::ENABLE_WEBTRANSPORT,
enable_webtransport as u64,
)?;
settings.insert(frame::SettingId::H3_DATAGRAM, enable_datagram as u64)?;
settings.insert(
frame::SettingId::WEBTRANSPORT_MAX_SESSIONS,
max_webtransport_sessions,
)?;
Ok(settings)
}
}
impl Default for Settings {
fn default() -> Self {
Self {
max_field_section_size: VarInt::MAX.0,
enable_webtransport: false,
enable_extended_connect: false,
enable_datagram: false,
max_webtransport_sessions: 0,
}
}
}
impl Settings {
/// https://datatracker.ietf.org/doc/html/draft-ietf-webtrans-http3/#section-3.1
/// Sets `SETTINGS_ENABLE_WEBTRANSPORT` if enabled
pub fn enable_webtransport(&self) -> bool {
self.enable_webtransport
}
/// Enable HTTP Datagrams, see https://datatracker.ietf.org/doc/rfc9297/ for details
pub fn enable_datagram(&self) -> bool {
self.enable_datagram
}
/// https://www.rfc-editor.org/info/rfc8441 defines an extended CONNECT method in Section 4,
/// enabled by the SETTINGS_ENABLE_CONNECT_PROTOCOL parameter.
/// That parameter is only defined for HTTP/2.
/// for extended CONNECT in HTTP/3; instead, the SETTINGS_ENABLE_WEBTRANSPORT setting implies that an endpoint supports extended CONNECT.
pub fn enable_extended_connect(&self) -> bool {
self.enable_extended_connect
}
}
impl Default for Config {
fn default() -> Self {
Self {
send_grease: true,
#[cfg(test)]
send_settings: true,
settings: Default::default(),
}
}
}