1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package net 6 7 import ( 8 "io" 9 "os" 10 "syscall" 11 "time" 12 ) 13 14 // TCPConn is an implementation of the Conn interface for TCP network 15 // connections. 16 type TCPConn struct { 17 conn 18 } 19 20 func newTCPConn(fd *netFD) *TCPConn { 21 return &TCPConn{conn{fd}} 22 } 23 24 // ReadFrom implements the io.ReaderFrom ReadFrom method. 25 func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) { 26 n, err := genericReadFrom(c, r) 27 if err != nil && err != io.EOF { 28 err = &OpError{Op: "read", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 29 } 30 return n, err 31 } 32 33 // CloseRead shuts down the reading side of the TCP connection. 34 // Most callers should just use Close. 35 func (c *TCPConn) CloseRead() error { 36 if !c.ok() { 37 return syscall.EINVAL 38 } 39 err := c.fd.closeRead() 40 if err != nil { 41 err = &OpError{Op: "close", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 42 } 43 return err 44 } 45 46 // CloseWrite shuts down the writing side of the TCP connection. 47 // Most callers should just use Close. 48 func (c *TCPConn) CloseWrite() error { 49 if !c.ok() { 50 return syscall.EINVAL 51 } 52 err := c.fd.closeWrite() 53 if err != nil { 54 err = &OpError{Op: "close", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 55 } 56 return err 57 } 58 59 // SetLinger sets the behavior of Close on a connection which still 60 // has data waiting to be sent or to be acknowledged. 61 // 62 // If sec < 0 (the default), the operating system finishes sending the 63 // data in the background. 64 // 65 // If sec == 0, the operating system discards any unsent or 66 // unacknowledged data. 67 // 68 // If sec > 0, the data is sent in the background as with sec < 0. On 69 // some operating systems after sec seconds have elapsed any remaining 70 // unsent data may be discarded. 71 func (c *TCPConn) SetLinger(sec int) error { 72 return &OpError{Op: "set", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: syscall.EPLAN9} 73 } 74 75 // SetKeepAlive sets whether the operating system should send 76 // keepalive messages on the connection. 77 func (c *TCPConn) SetKeepAlive(keepalive bool) error { 78 if !c.ok() { 79 return syscall.EPLAN9 80 } 81 if err := setKeepAlive(c.fd, keepalive); err != nil { 82 return &OpError{Op: "set", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 83 } 84 return nil 85 } 86 87 // SetKeepAlivePeriod sets period between keep alives. 88 func (c *TCPConn) SetKeepAlivePeriod(d time.Duration) error { 89 if !c.ok() { 90 return syscall.EPLAN9 91 } 92 if err := setKeepAlivePeriod(c.fd, d); err != nil { 93 return &OpError{Op: "set", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 94 } 95 return nil 96 } 97 98 // SetNoDelay controls whether the operating system should delay 99 // packet transmission in hopes of sending fewer packets (Nagle's 100 // algorithm). The default is true (no delay), meaning that data is 101 // sent as soon as possible after a Write. 102 func (c *TCPConn) SetNoDelay(noDelay bool) error { 103 return &OpError{Op: "set", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: syscall.EPLAN9} 104 } 105 106 // DialTCP connects to the remote address raddr on the network net, 107 // which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is 108 // used as the local address for the connection. 109 func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) { 110 return dialTCP(net, laddr, raddr, noDeadline) 111 } 112 113 func dialTCP(net string, laddr, raddr *TCPAddr, deadline time.Time) (*TCPConn, error) { 114 if !deadline.IsZero() { 115 panic("net.dialTCP: deadline not implemented on Plan 9") 116 } 117 switch net { 118 case "tcp", "tcp4", "tcp6": 119 default: 120 return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)} 121 } 122 if raddr == nil { 123 return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress} 124 } 125 fd, err := dialPlan9(net, laddr, raddr) 126 if err != nil { 127 return nil, err 128 } 129 return newTCPConn(fd), nil 130 } 131 132 // TCPListener is a TCP network listener. Clients should typically 133 // use variables of type Listener instead of assuming TCP. 134 type TCPListener struct { 135 fd *netFD 136 } 137 138 // AcceptTCP accepts the next incoming call and returns the new 139 // connection. 140 func (l *TCPListener) AcceptTCP() (*TCPConn, error) { 141 if l == nil || l.fd == nil || l.fd.ctl == nil { 142 return nil, syscall.EINVAL 143 } 144 fd, err := l.fd.acceptPlan9() 145 if err != nil { 146 return nil, err 147 } 148 return newTCPConn(fd), nil 149 } 150 151 // Accept implements the Accept method in the Listener interface; it 152 // waits for the next call and returns a generic Conn. 153 func (l *TCPListener) Accept() (Conn, error) { 154 if l == nil || l.fd == nil || l.fd.ctl == nil { 155 return nil, syscall.EINVAL 156 } 157 c, err := l.AcceptTCP() 158 if err != nil { 159 return nil, err 160 } 161 return c, nil 162 } 163 164 // Close stops listening on the TCP address. 165 // Already Accepted connections are not closed. 166 func (l *TCPListener) Close() error { 167 if l == nil || l.fd == nil || l.fd.ctl == nil { 168 return syscall.EINVAL 169 } 170 if _, err := l.fd.ctl.WriteString("hangup"); err != nil { 171 l.fd.ctl.Close() 172 return &OpError{Op: "close", Net: l.fd.dir, Source: nil, Addr: l.fd.laddr, Err: err} 173 } 174 err := l.fd.ctl.Close() 175 if err != nil { 176 err = &OpError{Op: "close", Net: l.fd.dir, Source: nil, Addr: l.fd.laddr, Err: err} 177 } 178 return err 179 } 180 181 // Addr returns the listener's network address, a *TCPAddr. 182 // The Addr returned is shared by all invocations of Addr, so 183 // do not modify it. 184 func (l *TCPListener) Addr() Addr { return l.fd.laddr } 185 186 // SetDeadline sets the deadline associated with the listener. 187 // A zero time value disables the deadline. 188 func (l *TCPListener) SetDeadline(t time.Time) error { 189 if l == nil || l.fd == nil || l.fd.ctl == nil { 190 return syscall.EINVAL 191 } 192 if err := l.fd.setDeadline(t); err != nil { 193 return &OpError{Op: "set", Net: l.fd.dir, Source: nil, Addr: l.fd.laddr, Err: err} 194 } 195 return nil 196 } 197 198 // File returns a copy of the underlying os.File, set to blocking 199 // mode. It is the caller's responsibility to close f when finished. 200 // Closing l does not affect f, and closing f does not affect l. 201 // 202 // The returned os.File's file descriptor is different from the 203 // connection's. Attempting to change properties of the original 204 // using this duplicate may or may not have the desired effect. 205 func (l *TCPListener) File() (f *os.File, err error) { 206 f, err = l.dup() 207 if err != nil { 208 err = &OpError{Op: "file", Net: l.fd.dir, Source: nil, Addr: l.fd.laddr, Err: err} 209 } 210 return 211 } 212 213 // ListenTCP announces on the TCP address laddr and returns a TCP 214 // listener. Net must be "tcp", "tcp4", or "tcp6". If laddr has a 215 // port of 0, ListenTCP will choose an available port. The caller can 216 // use the Addr method of TCPListener to retrieve the chosen address. 217 func ListenTCP(net string, laddr *TCPAddr) (*TCPListener, error) { 218 switch net { 219 case "tcp", "tcp4", "tcp6": 220 default: 221 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)} 222 } 223 if laddr == nil { 224 laddr = &TCPAddr{} 225 } 226 fd, err := listenPlan9(net, laddr) 227 if err != nil { 228 return nil, err 229 } 230 return &TCPListener{fd}, nil 231 } 232
