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// Copyright 2016 The CMux Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
package cmux
import (
"bufio"
"io"
"io/ioutil"
"net/http"
"strings"
"golang.org/x/net/http2"
"golang.org/x/net/http2/hpack"
)
// Any is a Matcher that matches any connection.
func Any() Matcher {
return func(r io.Reader) bool { return true }
}
// PrefixMatcher returns a matcher that matches a connection if it
// starts with any of the strings in strs.
func PrefixMatcher(strs ...string) Matcher {
pt := newPatriciaTreeString(strs...)
return pt.matchPrefix
}
var defaultHTTPMethods = []string{
"OPTIONS",
"GET",
"HEAD",
"POST",
"PUT",
"DELETE",
"TRACE",
"CONNECT",
}
// HTTP1Fast only matches the methods in the HTTP request.
//
// This matcher is very optimistic: if it returns true, it does not mean that
// the request is a valid HTTP response. If you want a correct but slower HTTP1
// matcher, use HTTP1 instead.
func HTTP1Fast(extMethods ...string) Matcher {
return PrefixMatcher(append(defaultHTTPMethods, extMethods...)...)
}
const maxHTTPRead = 4096
// HTTP1 parses the first line or upto 4096 bytes of the request to see if
// the conection contains an HTTP request.
func HTTP1() Matcher {
return func(r io.Reader) bool {
br := bufio.NewReader(&io.LimitedReader{R: r, N: maxHTTPRead})
l, part, err := br.ReadLine()
if err != nil || part {
return false
}
_, _, proto, ok := parseRequestLine(string(l))
if !ok {
return false
}
v, _, ok := http.ParseHTTPVersion(proto)
return ok && v == 1
}
}
// grabbed from net/http.
func parseRequestLine(line string) (method, uri, proto string, ok bool) {
s1 := strings.Index(line, " ")
s2 := strings.Index(line[s1+1:], " ")
if s1 < 0 || s2 < 0 {
return
}
s2 += s1 + 1
return line[:s1], line[s1+1 : s2], line[s2+1:], true
}
// HTTP2 parses the frame header of the first frame to detect whether the
// connection is an HTTP2 connection.
func HTTP2() Matcher {
return hasHTTP2Preface
}
// HTTP1HeaderField returns a matcher matching the header fields of the first
// request of an HTTP 1 connection.
func HTTP1HeaderField(name, value string) Matcher {
return func(r io.Reader) bool {
return matchHTTP1Field(r, name, value)
}
}
// HTTP2HeaderField resturns a matcher matching the header fields of the first
// headers frame.
func HTTP2HeaderField(name, value string) Matcher {
return func(r io.Reader) bool {
return matchHTTP2Field(ioutil.Discard, r, name, value)
}
}
// HTTP2MatchHeaderFieldSendSettings matches the header field and writes the
// settings to the server. Prefer HTTP2HeaderField over this one, if the client
// does not block on receiving a SETTING frame.
func HTTP2MatchHeaderFieldSendSettings(name, value string) MatchWriter {
return func(w io.Writer, r io.Reader) bool {
return matchHTTP2Field(w, r, name, value)
}
}
func hasHTTP2Preface(r io.Reader) bool {
var b [len(http2.ClientPreface)]byte
if _, err := io.ReadFull(r, b[:]); err != nil {
return false
}
return string(b[:]) == http2.ClientPreface
}
func matchHTTP1Field(r io.Reader, name, value string) (matched bool) {
req, err := http.ReadRequest(bufio.NewReader(r))
if err != nil {
return false
}
return req.Header.Get(name) == value
}
func matchHTTP2Field(w io.Writer, r io.Reader, name, value string) (matched bool) {
if !hasHTTP2Preface(r) {
return false
}
done := false
framer := http2.NewFramer(w, r)
hdec := hpack.NewDecoder(uint32(4<<10), func(hf hpack.HeaderField) {
if hf.Name == name {
done = true
if hf.Value == value {
matched = true
}
}
})
for {
f, err := framer.ReadFrame()
if err != nil {
return false
}
switch f := f.(type) {
case *http2.SettingsFrame:
if err := framer.WriteSettings(); err != nil {
return false
}
case *http2.ContinuationFrame:
if _, err := hdec.Write(f.HeaderBlockFragment()); err != nil {
return false
}
done = done || f.FrameHeader.Flags&http2.FlagHeadersEndHeaders != 0
case *http2.HeadersFrame:
if _, err := hdec.Write(f.HeaderBlockFragment()); err != nil {
return false
}
done = done || f.FrameHeader.Flags&http2.FlagHeadersEndHeaders != 0
}
if done {
return matched
}
}
}
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