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// Copyright 2017 Google Inc.
//
// 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 tcpproxy
import (
"bufio"
"bytes"
"context"
"net/http"
)
// AddHTTPHostRoute appends a route to the ipPort listener that
// routes to dest if the incoming HTTP/1.x Host header name is
// httpHost. If it doesn't match, rule processing continues for any
// additional routes on ipPort.
//
// The ipPort is any valid net.Listen TCP address.
func (p *Proxy) AddHTTPHostRoute(ipPort, httpHost string, dest Target) {
p.AddHTTPHostMatchRoute(ipPort, equals(httpHost), dest)
}
// AddHTTPHostMatchRoute appends a route to the ipPort listener that
// routes to dest if the incoming HTTP/1.x Host header name is
// accepted by matcher. If it doesn't match, rule processing continues
// for any additional routes on ipPort.
//
// The ipPort is any valid net.Listen TCP address.
func (p *Proxy) AddHTTPHostMatchRoute(ipPort string, match Matcher, dest Target) {
p.addRoute(ipPort, httpHostMatch{match, dest})
}
type httpHostMatch struct {
matcher Matcher
target Target
}
func (m httpHostMatch) match(br *bufio.Reader) (Target, string) {
hh := httpHostHeader(br)
if m.matcher(context.TODO(), hh) {
return m.target, hh
}
return nil, ""
}
// httpHostHeader returns the HTTP Host header from br without
// consuming any of its bytes. It returns "" if it can't find one.
func httpHostHeader(br *bufio.Reader) string {
const maxPeek = 4 << 10
peekSize := 0
for {
peekSize++
if peekSize > maxPeek {
b, _ := br.Peek(br.Buffered())
return httpHostHeaderFromBytes(b)
}
b, err := br.Peek(peekSize)
if n := br.Buffered(); n > peekSize {
b, _ = br.Peek(n)
peekSize = n
}
if len(b) > 0 {
if b[0] < 'A' || b[0] > 'Z' {
// Doesn't look like an HTTP verb
// (GET, POST, etc).
return ""
}
if bytes.Index(b, crlfcrlf) != -1 || bytes.Index(b, lflf) != -1 {
req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(b)))
if err != nil {
return ""
}
if len(req.Header["Host"]) > 1 {
// TODO(bradfitz): what does
// ReadRequest do if there are
// multiple Host headers?
return ""
}
return req.Host
}
}
if err != nil {
return httpHostHeaderFromBytes(b)
}
}
}
var (
lfHostColon = []byte("\nHost:")
lfhostColon = []byte("\nhost:")
crlf = []byte("\r\n")
lf = []byte("\n")
crlfcrlf = []byte("\r\n\r\n")
lflf = []byte("\n\n")
)
func httpHostHeaderFromBytes(b []byte) string {
if i := bytes.Index(b, lfHostColon); i != -1 {
return string(bytes.TrimSpace(untilEOL(b[i+len(lfHostColon):])))
}
if i := bytes.Index(b, lfhostColon); i != -1 {
return string(bytes.TrimSpace(untilEOL(b[i+len(lfhostColon):])))
}
return ""
}
// untilEOL returns v, truncated before the first '\n' byte, if any.
// The returned slice may include a '\r' at the end.
func untilEOL(v []byte) []byte {
if i := bytes.IndexByte(v, '\n'); i != -1 {
return v[:i]
}
return v
}
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