/usr/share/gocode/src/github.com/cockroachdb/cmux/cmux.go is in golang-github-cockroachdb-cmux-dev 0.0~git20170110.0.30d10be-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 | // 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 (
"bytes"
"fmt"
"io"
"net"
"sync"
)
// Matcher matches a connection based on its content.
type Matcher func(io.Reader) bool
// ErrorHandler handles an error and returns whether
// the mux should continue serving the listener.
type ErrorHandler func(error) bool
var _ net.Error = ErrNotMatched{}
// ErrNotMatched is returned whenever a connection is not matched by any of
// the matchers registered in the multiplexer.
type ErrNotMatched struct {
c net.Conn
}
func (e ErrNotMatched) Error() string {
return fmt.Sprintf("mux: connection %v not matched by an matcher",
e.c.RemoteAddr())
}
// Temporary implements the net.Error interface.
func (e ErrNotMatched) Temporary() bool { return true }
// Timeout implements the net.Error interface.
func (e ErrNotMatched) Timeout() bool { return false }
type errListenerClosed string
func (e errListenerClosed) Error() string { return string(e) }
func (e errListenerClosed) Temporary() bool { return false }
func (e errListenerClosed) Timeout() bool { return false }
// ErrListenerClosed is returned from muxListener.Accept when the underlying
// listener is closed.
var ErrListenerClosed = errListenerClosed("mux: listener closed")
// New instantiates a new connection multiplexer.
func New(l net.Listener) CMux {
return &cMux{
root: l,
bufLen: 1024,
errh: func(_ error) bool { return true },
donec: make(chan struct{}),
}
}
// CMux is a multiplexer for network connections.
type CMux interface {
// Match returns a net.Listener that sees (i.e., accepts) only
// the connections matched by at least one of the matcher.
//
// The order used to call Match determines the priority of matchers.
Match(...Matcher) net.Listener
// Serve starts multiplexing the listener. Serve blocks and perhaps
// should be invoked concurrently within a go routine.
Serve() error
// HandleError registers an error handler that handles listener errors.
HandleError(ErrorHandler)
}
type matchersListener struct {
ss []Matcher
l muxListener
}
type cMux struct {
root net.Listener
bufLen int
errh ErrorHandler
donec chan struct{}
sls []matchersListener
}
func (m *cMux) Match(matchers ...Matcher) net.Listener {
ml := muxListener{
Listener: m.root,
connc: make(chan net.Conn, m.bufLen),
}
m.sls = append(m.sls, matchersListener{ss: matchers, l: ml})
return ml
}
func (m *cMux) Serve() error {
var wg sync.WaitGroup
defer func() {
close(m.donec)
wg.Wait()
for _, sl := range m.sls {
close(sl.l.connc)
// Drain the connections enqueued for the listener.
for c := range sl.l.connc {
_ = c.Close()
}
}
}()
for {
c, err := m.root.Accept()
if err != nil {
if !m.handleErr(err) {
return err
}
continue
}
wg.Add(1)
go m.serve(c, m.donec, &wg)
}
}
func (m *cMux) serve(c net.Conn, donec <-chan struct{}, wg *sync.WaitGroup) {
defer wg.Done()
muc := newMuxConn(c)
for _, sl := range m.sls {
for _, s := range sl.ss {
matched := s(muc.getSniffer())
if matched {
select {
case sl.l.connc <- muc:
case <-donec:
_ = c.Close()
}
return
}
}
}
_ = c.Close()
err := ErrNotMatched{c: c}
if !m.handleErr(err) {
_ = m.root.Close()
}
}
func (m *cMux) HandleError(h ErrorHandler) {
m.errh = h
}
func (m *cMux) handleErr(err error) bool {
if !m.errh(err) {
return false
}
if ne, ok := err.(net.Error); ok {
return ne.Temporary()
}
return false
}
type muxListener struct {
net.Listener
connc chan net.Conn
}
func (l muxListener) Accept() (net.Conn, error) {
c, ok := <-l.connc
if !ok {
return nil, ErrListenerClosed
}
return c, nil
}
// MuxConn wraps a net.Conn and provides transparent sniffing of connection data.
type MuxConn struct {
net.Conn
buf bytes.Buffer
sniffer bufferedReader
}
func newMuxConn(c net.Conn) *MuxConn {
return &MuxConn{
Conn: c,
}
}
// From the io.Reader documentation:
//
// When Read encounters an error or end-of-file condition after
// successfully reading n > 0 bytes, it returns the number of
// bytes read. It may return the (non-nil) error from the same call
// or return the error (and n == 0) from a subsequent call.
// An instance of this general case is that a Reader returning
// a non-zero number of bytes at the end of the input stream may
// return either err == EOF or err == nil. The next Read should
// return 0, EOF.
func (m *MuxConn) Read(p []byte) (int, error) {
if n, err := m.buf.Read(p); err != io.EOF {
return n, err
}
return m.Conn.Read(p)
}
func (m *MuxConn) getSniffer() io.Reader {
m.sniffer = bufferedReader{source: m.Conn, buffer: &m.buf, bufferSize: m.buf.Len()}
return &m.sniffer
}
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