Files
h2/src/frame/headers.rs
2017-08-30 18:16:21 -04:00

558 lines
14 KiB
Rust

use super::{StreamId, StreamDependency};
use ConnectionError;
use hpack;
use frame::{self, Frame, Head, Kind, Error};
use HeaderMap;
use error::Reason::*;
use http::{version, uri, Request, Response, Method, StatusCode, Uri};
use http::header::{self, HeaderName, HeaderValue};
use bytes::{BytesMut, Bytes};
use byteorder::{BigEndian, ByteOrder};
use string::String;
use std::fmt;
use std::io::Cursor;
/// Header frame
///
/// This could be either a request or a response.
#[derive(Debug)]
pub struct Headers {
/// The ID of the stream with which this frame is associated.
stream_id: StreamId,
/// The stream dependency information, if any.
stream_dep: Option<StreamDependency>,
/// The decoded header fields
fields: HeaderMap,
/// Pseudo headers, these are broken out as they must be sent as part of the
/// headers frame.
pseudo: Pseudo,
/// The associated flags
flags: HeadersFlag,
}
#[derive(Copy, Clone, Eq, PartialEq)]
pub struct HeadersFlag(u8);
#[derive(Debug)]
pub struct PushPromise {
/// The ID of the stream with which this frame is associated.
stream_id: StreamId,
/// The ID of the stream being reserved by this PushPromise.
promised_id: StreamId,
/// The associated flags
flags: PushPromiseFlag,
}
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub struct PushPromiseFlag(u8);
#[derive(Debug)]
pub struct Continuation {
/// Stream ID of continuation frame
stream_id: StreamId,
/// Argument to pass to the HPACK encoder to resume encoding
hpack: hpack::EncodeState,
/// remaining headers to encode
headers: Iter,
}
#[derive(Debug, Default)]
pub struct Pseudo {
// Request
method: Option<Method>,
scheme: Option<String<Bytes>>,
authority: Option<String<Bytes>>,
path: Option<String<Bytes>>,
// Response
status: Option<StatusCode>,
}
#[derive(Debug)]
pub struct Iter {
/// Pseudo headers
pseudo: Option<Pseudo>,
/// Header fields
fields: header::IntoIter<HeaderValue>,
}
const END_STREAM: u8 = 0x1;
const END_HEADERS: u8 = 0x4;
const PADDED: u8 = 0x8;
const PRIORITY: u8 = 0x20;
const ALL: u8 = END_STREAM
| END_HEADERS
| PADDED
| PRIORITY;
// ===== impl Headers =====
impl Headers {
/// Create a new HEADERS frame
pub fn new(stream_id: StreamId, pseudo: Pseudo, fields: HeaderMap) -> Self {
Headers {
stream_id: stream_id,
stream_dep: None,
fields: fields,
pseudo: pseudo,
flags: HeadersFlag::default(),
}
}
pub fn trailers(stream_id: StreamId, fields: HeaderMap) -> Self {
let mut flags = HeadersFlag::default();
flags.set_end_stream();
Headers {
stream_id,
stream_dep: None,
fields: fields,
pseudo: Pseudo::default(),
flags: flags,
}
}
/// Loads the header frame but doesn't actually do HPACK decoding.
///
/// HPACK decoding is done in the `load_hpack` step.
pub fn load(head: Head, mut src: BytesMut)
-> Result<(Self, BytesMut), Error>
{
let flags = HeadersFlag(head.flag());
let mut pad = 0;
trace!("loading headers; flags={:?}", flags);
// Read the padding length
if flags.is_padded() {
// TODO: Ensure payload is sized correctly
pad = src[0] as usize;
// Drop the padding
let _ = src.split_to(1);
}
// Read the stream dependency
let stream_dep = if flags.is_priority() {
let stream_dep = StreamDependency::load(&src[..5])?;
if stream_dep.dependency_id() == head.stream_id() {
return Err(Error::InvalidDependencyId);
}
// Drop the next 5 bytes
let _ = src.split_to(5);
Some(stream_dep)
} else {
None
};
if pad > 0 {
if pad > src.len() {
return Err(Error::TooMuchPadding);
}
let len = src.len() - pad;
src.truncate(len);
}
let headers = Headers {
stream_id: head.stream_id(),
stream_dep: stream_dep,
fields: HeaderMap::new(),
pseudo: Pseudo::default(),
flags: flags,
};
Ok((headers, src))
}
pub fn load_hpack(&mut self,
src: BytesMut,
decoder: &mut hpack::Decoder)
-> Result<(), Error>
{
let mut reg = false;
let mut malformed = false;
macro_rules! set_pseudo {
($field:ident, $val:expr) => {{
if reg {
trace!("load_hpack; header malformed -- pseudo not at head of block");
malformed = true;
} else if self.pseudo.$field.is_some() {
trace!("load_hpack; header malformed -- repeated pseudo");
malformed = true;
} else {
self.pseudo.$field = Some($val);
}
}}
}
let mut src = Cursor::new(src.freeze());
// At this point, we're going to assume that the hpack encoded headers
// contain the entire payload. Later, we need to check for stream
// priority.
//
// TODO: Provide a way to abort decoding if an error is hit.
let res = decoder.decode(&mut src, |header| {
use hpack::Header::*;
match header {
Field { name, value } => {
// Connection level header fields are not supported and must
// result in a protocol error.
if name == header::CONNECTION {
trace!("load_hpack; connection level header");
malformed = true;
} else if name == header::TE && value != "trailers" {
trace!("load_hpack; TE header not set to trailers; val={:?}", value);
malformed = true;
} else {
reg = true;
self.fields.append(name, value);
}
}
Authority(v) => set_pseudo!(authority, v),
Method(v) => set_pseudo!(method, v),
Scheme(v) => set_pseudo!(scheme, v),
Path(v) => set_pseudo!(path, v),
Status(v) => set_pseudo!(status, v),
}
});
if let Err(e) = res {
trace!("hpack decoding error; err={:?}", e);
return Err(e.into());
}
if malformed {
trace!("malformed message");
return Err(Error::MalformedMessage.into());
}
Ok(())
}
pub fn stream_id(&self) -> StreamId {
self.stream_id
}
pub fn is_end_headers(&self) -> bool {
self.flags.is_end_headers()
}
pub fn is_end_stream(&self) -> bool {
self.flags.is_end_stream()
}
pub fn set_end_stream(&mut self) {
self.flags.set_end_stream()
}
pub fn into_response(self) -> Result<Response<()>, ConnectionError> {
let mut b = Response::builder();
if let Some(status) = self.pseudo.status {
b.status(status);
}
let mut response = try!(b.body(()));
*response.headers_mut() = self.fields;
Ok(response)
}
pub fn into_request(self) -> Result<Request<()>, ConnectionError> {
let mut b = Request::builder();
b.version(version::HTTP_2);
if let Some(method) = self.pseudo.method {
b.method(method);
}
// Specifying :status for a request is a protocol error
if self.pseudo.status.is_some() {
return Err(ProtocolError.into());
}
// Convert the URI
let mut parts = uri::Parts::default();
if let Some(scheme) = self.pseudo.scheme {
// TODO: Don't unwrap
parts.scheme = Some(uri::Scheme::from_shared(scheme.into_inner()).unwrap());
}
if let Some(authority) = self.pseudo.authority {
// TODO: Don't unwrap
parts.authority = Some(uri::Authority::from_shared(authority.into_inner()).unwrap());
}
if let Some(path) = self.pseudo.path {
// TODO: Don't unwrap
parts.path_and_query = Some(uri::PathAndQuery::from_shared(path.into_inner()).unwrap());
}
b.uri(parts);
let mut request = try!(b.body(()));
*request.headers_mut() = self.fields;
Ok(request)
}
pub fn into_fields(self) -> HeaderMap {
self.fields
}
pub fn encode(self, encoder: &mut hpack::Encoder, dst: &mut BytesMut)
-> Option<Continuation>
{
let head = self.head();
let pos = dst.len();
// At this point, we don't know how big the h2 frame will be.
// So, we write the head with length 0, then write the body, and
// finally write the length once we know the size.
head.encode(0, dst);
// Encode the frame
let mut headers = Iter {
pseudo: Some(self.pseudo),
fields: self.fields.into_iter(),
};
let ret = match encoder.encode(None, &mut headers, dst) {
hpack::Encode::Full => None,
hpack::Encode::Partial(state) => {
Some(Continuation {
stream_id: self.stream_id,
hpack: state,
headers: headers,
})
}
};
// Compute the frame length
let len = (dst.len() - pos) - frame::HEADER_LEN;
// Write the frame length
BigEndian::write_uint(&mut dst[pos..pos+3], len as u64, 3);
ret
}
fn head(&self) -> Head {
Head::new(Kind::Headers, self.flags.into(), self.stream_id)
}
}
impl<T> From<Headers> for Frame<T> {
fn from(src: Headers) -> Self {
Frame::Headers(src)
}
}
// ===== impl PushPromise =====
impl PushPromise {
pub fn load(head: Head, payload: &[u8])
-> Result<Self, Error>
{
let flags = PushPromiseFlag(head.flag());
// TODO: Handle padding
let (promised_id, _) = StreamId::parse(&payload[..4]);
Ok(PushPromise {
stream_id: head.stream_id(),
promised_id: promised_id,
flags: flags,
})
}
pub fn stream_id(&self) -> StreamId {
self.stream_id
}
pub fn promised_id(&self) -> StreamId {
self.promised_id
}
}
impl<T> From<PushPromise> for Frame<T> {
fn from(src: PushPromise) -> Self {
Frame::PushPromise(src)
}
}
// ===== impl Pseudo =====
impl Pseudo {
pub fn request(method: Method, uri: Uri) -> Self {
let parts = uri::Parts::from(uri);
fn to_string(src: Bytes) -> String<Bytes> {
unsafe { String::from_utf8_unchecked(src) }
}
let path = parts.path_and_query
.map(|v| v.into())
.unwrap_or_else(|| Bytes::from_static(b"/"));
let mut pseudo = Pseudo {
method: Some(method),
scheme: None,
authority: None,
path: Some(to_string(path)),
status: None,
};
// If the URI includes a scheme component, add it to the pseudo headers
//
// TODO: Scheme must be set...
if let Some(scheme) = parts.scheme {
pseudo.set_scheme(to_string(scheme.into()));
}
// If the URI includes an authority component, add it to the pseudo
// headers
if let Some(authority) = parts.authority {
pseudo.set_authority(to_string(authority.into()));
}
pseudo
}
pub fn response(status: StatusCode) -> Self {
Pseudo {
method: None,
scheme: None,
authority: None,
path: None,
status: Some(status),
}
}
pub fn set_scheme(&mut self, scheme: String<Bytes>) {
self.scheme = Some(scheme);
}
pub fn set_authority(&mut self, authority: String<Bytes>) {
self.authority = Some(authority);
}
}
// ===== impl Iter =====
impl Iterator for Iter {
type Item = hpack::Header<Option<HeaderName>>;
fn next(&mut self) -> Option<Self::Item> {
use hpack::Header::*;
if let Some(ref mut pseudo) = self.pseudo {
if let Some(method) = pseudo.method.take() {
return Some(Method(method));
}
if let Some(scheme) = pseudo.scheme.take() {
return Some(Scheme(scheme));
}
if let Some(authority) = pseudo.authority.take() {
return Some(Authority(authority));
}
if let Some(path) = pseudo.path.take() {
return Some(Path(path));
}
if let Some(status) = pseudo.status.take() {
return Some(Status(status));
}
}
self.pseudo = None;
self.fields.next()
.map(|(name, value)| {
Field { name: name, value: value}
})
}
}
// ===== impl HeadersFlag =====
impl HeadersFlag {
pub fn empty() -> HeadersFlag {
HeadersFlag(0)
}
pub fn load(bits: u8) -> HeadersFlag {
HeadersFlag(bits & ALL)
}
pub fn is_end_stream(&self) -> bool {
self.0 & END_STREAM == END_STREAM
}
pub fn set_end_stream(&mut self) {
self.0 |= END_STREAM
}
pub fn is_end_headers(&self) -> bool {
self.0 & END_HEADERS == END_HEADERS
}
pub fn is_padded(&self) -> bool {
self.0 & PADDED == PADDED
}
pub fn is_priority(&self) -> bool {
self.0 & PRIORITY == PRIORITY
}
}
impl Default for HeadersFlag {
/// Returns a `HeadersFlag` value with `END_HEADERS` set.
fn default() -> Self {
HeadersFlag(END_HEADERS)
}
}
impl From<HeadersFlag> for u8 {
fn from(src: HeadersFlag) -> u8 {
src.0
}
}
impl fmt::Debug for HeadersFlag {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
fmt.debug_struct("HeadersFlag")
.field("end_stream", &self.is_end_stream())
.field("end_headers", &self.is_end_headers())
.field("padded", &self.is_padded())
.field("priority", &self.is_priority())
.finish()
}
}