This reverts commit edb2377540.
See https://github.com/snapview/tungstenite-rs/pull/328#issuecomment-1480349206
pull/341/head
Daniel Abramov
2 years ago
parent
edb2377540
commit
42b8797e8b
File diff suppressed because it is too large
Load Diff
@ -1,442 +0,0 @@ |
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use std::convert::TryFrom; |
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|
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use bytes::BytesMut; |
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use flate2::{Compress, Compression, Decompress, FlushCompress, FlushDecompress, Status}; |
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use headers::WebsocketExtension; |
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use http::HeaderValue; |
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use thiserror::Error; |
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|
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use crate::protocol::Role; |
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|
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const PER_MESSAGE_DEFLATE: &str = "permessage-deflate"; |
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const CLIENT_NO_CONTEXT_TAKEOVER: &str = "client_no_context_takeover"; |
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const SERVER_NO_CONTEXT_TAKEOVER: &str = "server_no_context_takeover"; |
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const CLIENT_MAX_WINDOW_BITS: &str = "client_max_window_bits"; |
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const SERVER_MAX_WINDOW_BITS: &str = "server_max_window_bits"; |
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|
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const TRAILER: [u8; 4] = [0x00, 0x00, 0xff, 0xff]; |
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|
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/// Errors from `permessage-deflate` extension.
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#[derive(Debug, Error)] |
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pub enum DeflateError { |
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/// Compress failed
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#[error("Failed to compress")] |
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Compress(#[source] std::io::Error), |
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/// Decompress failed
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#[error("Failed to decompress")] |
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Decompress(#[source] std::io::Error), |
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/// Extension negotiation failed.
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#[error("Extension negotiation failed")] |
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Negotiation(#[source] NegotiationError), |
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} |
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|
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/// Errors from `permessage-deflate` extension negotiation.
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#[derive(Debug, Error)] |
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pub enum NegotiationError { |
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/// Unknown parameter in a negotiation response.
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#[error("Unknown parameter in a negotiation response: {0}")] |
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UnknownParameter(String), |
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/// Duplicate parameter in a negotiation response.
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#[error("Duplicate parameter in a negotiation response: {0}")] |
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DuplicateParameter(String), |
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/// Received `client_max_window_bits` in a negotiation response for an offer without it.
|
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#[error("Received client_max_window_bits in a negotiation response for an offer without it")] |
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UnexpectedClientMaxWindowBits, |
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/// Received unsupported `server_max_window_bits` in a negotiation response.
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#[error("Received unsupported server_max_window_bits in a negotiation response")] |
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ServerMaxWindowBitsNotSupported, |
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/// Invalid `client_max_window_bits` value in a negotiation response.
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#[error("Invalid client_max_window_bits value in a negotiation response: {0}")] |
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InvalidClientMaxWindowBitsValue(String), |
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/// Invalid `server_max_window_bits` value in a negotiation response.
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#[error("Invalid server_max_window_bits value in a negotiation response: {0}")] |
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InvalidServerMaxWindowBitsValue(String), |
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/// Missing `server_max_window_bits` value in a negotiation response.
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#[error("Missing server_max_window_bits value in a negotiation response")] |
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MissingServerMaxWindowBitsValue, |
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} |
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|
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// Parameters `server_max_window_bits` and `client_max_window_bits` are not supported for now
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// because custom window size requires `flate2/zlib` feature.
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/// Configurations for `permessage-deflate` Per-Message Compression Extension.
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#[derive(Clone, Copy, Debug, Default)] |
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pub struct DeflateConfig { |
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/// Compression level.
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pub compression: Compression, |
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/// Request the peer server not to use context takeover.
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pub server_no_context_takeover: bool, |
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/// Hint that context takeover is not used.
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pub client_no_context_takeover: bool, |
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} |
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impl DeflateConfig { |
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pub(crate) fn name(&self) -> &str { |
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PER_MESSAGE_DEFLATE |
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} |
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/// Value for `Sec-WebSocket-Extensions` request header.
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pub(crate) fn generate_offer(&self) -> WebsocketExtension { |
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let mut offers = Vec::new(); |
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if self.server_no_context_takeover { |
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offers.push(HeaderValue::from_static(SERVER_NO_CONTEXT_TAKEOVER)); |
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} |
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|
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// > a client informs the peer server of a hint that even if the server doesn't include the
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// > "client_no_context_takeover" extension parameter in the corresponding
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// > extension negotiation response to the offer, the client is not going
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// > to use context takeover.
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// > https://www.rfc-editor.org/rfc/rfc7692#section-7.1.1.2
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if self.client_no_context_takeover { |
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offers.push(HeaderValue::from_static(CLIENT_NO_CONTEXT_TAKEOVER)); |
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} |
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to_header_value(&offers) |
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} |
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/// Returns negotiation response based on offers and `DeflateContext` to manage per message compression.
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pub(crate) fn accept_offer( |
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&self, |
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offers: &headers::SecWebsocketExtensions, |
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) -> Option<(WebsocketExtension, DeflateContext)> { |
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// Accept the first valid offer for `permessage-deflate`.
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// A server MUST decline an extension negotiation offer for this
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// extension if any of the following conditions are met:
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// 1. The negotiation offer contains an extension parameter not defined for use in an offer.
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// 2. The negotiation offer contains an extension parameter with an invalid value.
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// 3. The negotiation offer contains multiple extension parameters with the same name.
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// 4. The server doesn't support the offered configuration.
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offers.iter().find_map(|extension| { |
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if let Some(params) = (extension.name() == self.name()).then(|| extension.params()) { |
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let mut config = |
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DeflateConfig { compression: self.compression, ..DeflateConfig::default() }; |
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let mut agreed = Vec::new(); |
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let mut seen_server_no_context_takeover = false; |
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let mut seen_client_no_context_takeover = false; |
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let mut seen_client_max_window_bits = false; |
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for (key, val) in params { |
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match key { |
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SERVER_NO_CONTEXT_TAKEOVER => { |
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// Invalid offer with multiple params with same name is declined.
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if seen_server_no_context_takeover { |
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return None; |
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} |
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seen_server_no_context_takeover = true; |
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config.server_no_context_takeover = true; |
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agreed.push(HeaderValue::from_static(SERVER_NO_CONTEXT_TAKEOVER)); |
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} |
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CLIENT_NO_CONTEXT_TAKEOVER => { |
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// Invalid offer with multiple params with same name is declined.
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if seen_client_no_context_takeover { |
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return None; |
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} |
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seen_client_no_context_takeover = true; |
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config.client_no_context_takeover = true; |
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agreed.push(HeaderValue::from_static(CLIENT_NO_CONTEXT_TAKEOVER)); |
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} |
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// Max window bits are not supported at the moment.
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SERVER_MAX_WINDOW_BITS => { |
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// Decline offer with invalid parameter value.
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// `server_max_window_bits` requires a value in range [8, 15].
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if let Some(bits) = val { |
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if !is_valid_max_window_bits(bits) { |
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return None; |
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} |
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} else { |
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return None; |
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} |
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// A server declines an extension negotiation offer with this parameter
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// if the server doesn't support it.
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return None; |
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} |
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// Not supported, but server may ignore and accept the offer.
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CLIENT_MAX_WINDOW_BITS => { |
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// Decline offer with invalid parameter value.
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// `client_max_window_bits` requires a value in range [8, 15] or no value.
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if let Some(bits) = val { |
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if !is_valid_max_window_bits(bits) { |
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return None; |
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} |
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} |
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// Invalid offer with multiple params with same name is declined.
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if seen_client_max_window_bits { |
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return None; |
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} |
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seen_client_max_window_bits = true; |
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} |
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// Offer with unknown parameter MUST be declined.
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_ => { |
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return None; |
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} |
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} |
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} |
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Some((to_header_value(&agreed), DeflateContext::new(Role::Server, config))) |
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} else { |
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None |
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} |
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}) |
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} |
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pub(crate) fn accept_response<'a>( |
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&'a self, |
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agreed: impl Iterator<Item = (&'a str, Option<&'a str>)>, |
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) -> Result<DeflateContext, DeflateError> { |
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let mut config = DeflateConfig { |
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compression: self.compression, |
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// If this was hinted in the offer, the client won't use context takeover
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// even if the response doesn't include it.
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// See `generate_offer`.
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client_no_context_takeover: self.client_no_context_takeover, |
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..DeflateConfig::default() |
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}; |
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let mut seen_server_no_context_takeover = false; |
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let mut seen_client_no_context_takeover = false; |
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// A client MUST _Fail the WebSocket Connection_ if the peer server
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// accepted an extension negotiation offer for this extension with an
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// extension negotiation response meeting any of the following
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// conditions:
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// 1. The negotiation response contains an extension parameter not defined for use in a response.
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// 2. The negotiation response contains an extension parameter with an invalid value.
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// 3. The negotiation response contains multiple extension parameters with the same name.
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// 4. The client does not support the configuration that the response represents.
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for (key, val) in agreed { |
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match key { |
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SERVER_NO_CONTEXT_TAKEOVER => { |
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// Fail the connection when the response contains multiple parameters with the same name.
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if seen_server_no_context_takeover { |
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return Err(DeflateError::Negotiation( |
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NegotiationError::DuplicateParameter(key.to_owned()), |
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)); |
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} |
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seen_server_no_context_takeover = true; |
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// A server MAY include the "server_no_context_takeover" extension
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// parameter in an extension negotiation response even if the extension
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// negotiation offer being accepted by the extension negotiation
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// response didn't include the "server_no_context_takeover" extension
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// parameter.
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config.server_no_context_takeover = true; |
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} |
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CLIENT_NO_CONTEXT_TAKEOVER => { |
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// Fail the connection when the response contains multiple parameters with the same name.
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if seen_client_no_context_takeover { |
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return Err(DeflateError::Negotiation( |
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NegotiationError::DuplicateParameter(key.to_owned()), |
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)); |
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} |
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seen_client_no_context_takeover = true; |
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// The server may include this parameter in the response and the client MUST support it.
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config.client_no_context_takeover = true; |
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} |
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SERVER_MAX_WINDOW_BITS => { |
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// Fail the connection when the response contains a parameter with invalid value.
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if let Some(bits) = val { |
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if !is_valid_max_window_bits(bits) { |
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return Err(DeflateError::Negotiation( |
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NegotiationError::InvalidServerMaxWindowBitsValue(bits.to_owned()), |
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)); |
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} |
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} else { |
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return Err(DeflateError::Negotiation( |
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NegotiationError::MissingServerMaxWindowBitsValue, |
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)); |
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} |
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// A server may include the "server_max_window_bits" extension parameter
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// in an extension negotiation response even if the extension
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// negotiation offer being accepted by the response didn't include the
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// "server_max_window_bits" extension parameter.
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//
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// However, but we need to fail the connection because we don't support it (condition 4).
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return Err(DeflateError::Negotiation( |
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NegotiationError::ServerMaxWindowBitsNotSupported, |
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)); |
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} |
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CLIENT_MAX_WINDOW_BITS => { |
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// Fail the connection when the response contains a parameter with invalid value.
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if let Some(bits) = val { |
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if !is_valid_max_window_bits(bits) { |
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return Err(DeflateError::Negotiation( |
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NegotiationError::InvalidClientMaxWindowBitsValue(bits.to_owned()), |
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)); |
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} |
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} |
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|
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// Fail the connection because the parameter is invalid when the client didn't offer.
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//
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// If a received extension negotiation offer doesn't have the
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// "client_max_window_bits" extension parameter, the corresponding
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// extension negotiation response to the offer MUST NOT include the
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// "client_max_window_bits" extension parameter.
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return Err(DeflateError::Negotiation( |
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NegotiationError::UnexpectedClientMaxWindowBits, |
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)); |
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} |
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// Response with unknown parameter MUST fail the WebSocket connection.
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_ => { |
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return Err(DeflateError::Negotiation(NegotiationError::UnknownParameter( |
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key.to_owned(), |
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))); |
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} |
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} |
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} |
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Ok(DeflateContext::new(Role::Client, config)) |
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} |
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} |
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|
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// A valid `client_max_window_bits` is no value or an integer in range `[8, 15]` without leading zeros.
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// A valid `server_max_window_bits` is an integer in range `[8, 15]` without leading zeros.
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fn is_valid_max_window_bits(bits: &str) -> bool { |
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// Note that values from `headers::SecWebSocketExtensions` is unquoted.
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matches!(bits, "8" | "9" | "10" | "11" | "12" | "13" | "14" | "15") |
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} |
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#[cfg(test)] |
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mod tests { |
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use super::is_valid_max_window_bits; |
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#[test] |
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fn valid_max_window_bits() { |
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for bits in 8..=15 { |
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assert!(is_valid_max_window_bits(&bits.to_string())); |
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} |
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} |
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|
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#[test] |
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fn invalid_max_window_bits() { |
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assert!(!is_valid_max_window_bits("")); |
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assert!(!is_valid_max_window_bits("0")); |
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assert!(!is_valid_max_window_bits("08")); |
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assert!(!is_valid_max_window_bits("+8")); |
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assert!(!is_valid_max_window_bits("-8")); |
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} |
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} |
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|
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#[derive(Debug)] |
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/// Manages per message compression using DEFLATE.
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pub struct DeflateContext { |
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role: Role, |
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config: DeflateConfig, |
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compressor: Compress, |
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decompressor: Decompress, |
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} |
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|
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impl DeflateContext { |
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fn new(role: Role, config: DeflateConfig) -> Self { |
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DeflateContext { |
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role, |
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config, |
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compressor: Compress::new(config.compression, false), |
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decompressor: Decompress::new(false), |
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} |
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} |
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|
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fn own_context_takeover(&self) -> bool { |
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match self.role { |
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Role::Server => !self.config.server_no_context_takeover, |
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Role::Client => !self.config.client_no_context_takeover, |
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} |
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} |
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|
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fn peer_context_takeover(&self) -> bool { |
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match self.role { |
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Role::Server => !self.config.client_no_context_takeover, |
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Role::Client => !self.config.server_no_context_takeover, |
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} |
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} |
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|
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// Compress the data of message.
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pub(crate) fn compress(&mut self, data: &[u8]) -> Result<Vec<u8>, DeflateError> { |
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// https://datatracker.ietf.org/doc/html/rfc7692#section-7.2.1
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// 1. Compress all the octets of the payload of the message using DEFLATE.
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let mut output = Vec::with_capacity(data.len()); |
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let before_in = self.compressor.total_in() as usize; |
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while (self.compressor.total_in() as usize) - before_in < data.len() { |
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let offset = (self.compressor.total_in() as usize) - before_in; |
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match self |
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.compressor |
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.compress_vec(&data[offset..], &mut output, FlushCompress::None) |
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.map_err(|e| DeflateError::Compress(e.into()))? |
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{ |
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Status::Ok => continue, |
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Status::BufError => output.reserve(4096), |
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Status::StreamEnd => break, |
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} |
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} |
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// 2. If the resulting data does not end with an empty DEFLATE block
|
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// with no compression (the "BTYPE" bits are set to 00), append an
|
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// empty DEFLATE block with no compression to the tail end.
|
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while !output.ends_with(&TRAILER) { |
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output.reserve(5); |
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match self |
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.compressor |
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.compress_vec(&[], &mut output, FlushCompress::Sync) |
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.map_err(|e| DeflateError::Compress(e.into()))? |
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{ |
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Status::Ok | Status::BufError => continue, |
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Status::StreamEnd => break, |
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} |
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} |
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// 3. Remove 4 octets (that are 0x00 0x00 0xff 0xff) from the tail end.
|
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// After this step, the last octet of the compressed data contains
|
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// (possibly part of) the DEFLATE header bits with the "BTYPE" bits
|
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// set to 00.
|
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output.truncate(output.len() - 4); |
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|
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if !self.own_context_takeover() { |
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self.compressor.reset(); |
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} |
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|
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Ok(output) |
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} |
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|
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pub(crate) fn decompress( |
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&mut self, |
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mut data: Vec<u8>, |
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is_final: bool, |
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) -> Result<Vec<u8>, DeflateError> { |
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if is_final { |
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data.extend_from_slice(&TRAILER); |
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} |
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|
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let before_in = self.decompressor.total_in() as usize; |
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let mut output = Vec::with_capacity(2 * data.len()); |
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loop { |
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let offset = (self.decompressor.total_in() as usize) - before_in; |
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match self |
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.decompressor |
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.decompress_vec(&data[offset..], &mut output, FlushDecompress::None) |
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.map_err(|e| DeflateError::Decompress(e.into()))? |
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{ |
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Status::Ok => output.reserve(2 * output.len()), |
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Status::BufError | Status::StreamEnd => break, |
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} |
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} |
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|
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if is_final && !self.peer_context_takeover() { |
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self.decompressor.reset(false); |
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} |
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|
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Ok(output) |
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} |
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} |
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|
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fn to_header_value(params: &[HeaderValue]) -> WebsocketExtension { |
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let mut buf = BytesMut::from(PER_MESSAGE_DEFLATE.as_bytes()); |
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for param in params { |
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buf.extend_from_slice(b"; "); |
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buf.extend_from_slice(param.as_bytes()); |
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} |
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let header = HeaderValue::from_maybe_shared(buf.freeze()) |
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.expect("semicolon separated HeaderValue is valid"); |
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WebsocketExtension::try_from(header).expect("valid extension") |
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} |
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@ -1,4 +0,0 @@ |
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//! [Per-Message Compression Extensions][rfc7692]
|
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//!
|
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//! [rfc7692]: https://tools.ietf.org/html/rfc7692
|
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pub mod deflate; |
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@ -1,18 +0,0 @@ |
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//! WebSocket extensions.
|
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// Only `permessage-deflate` is supported at the moment.
|
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|
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#[cfg(feature = "deflate")] |
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mod compression; |
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#[cfg(feature = "deflate")] |
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use compression::deflate::DeflateContext; |
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#[cfg(feature = "deflate")] |
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pub use compression::deflate::{DeflateConfig, DeflateError}; |
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|
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/// Container for configured extensions.
|
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#[derive(Debug, Default)] |
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#[allow(missing_copy_implementations)] |
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pub struct Extensions { |
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// Per-Message Compression. Only `permessage-deflate` is supported.
|
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#[cfg(feature = "deflate")] |
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pub(crate) compression: Option<DeflateContext>, |
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} |
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