libgo/go/net/tcpsock.go

   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         "context"
   9         "internal/itoa"
  10         "io"
  11         "net/netip"
  12         "os"
  13         "syscall"
  14         "time"
  15 )
  16
  17 // BUG(mikio): On JS and Windows, the File method of TCPConn and
  18 // TCPListener is not implemented.
  19
  20 // TCPAddr represents the address of a TCP end point.
  21 type TCPAddr struct {
  22         IP   IP
  23         Port int
  24         Zone string // IPv6 scoped addressing zone
  25 }
  26
  27 // AddrPort returns the TCPAddr a as a netip.AddrPort.
  28 //
  29 // If a.Port does not fit in a uint16, it's silently truncated.
  30 //
  31 // If a is nil, a zero value is returned.
  32 func (a *TCPAddr) AddrPort() netip.AddrPort {
  33         if a == nil {
  34                 return netip.AddrPort{}
  35         }
  36         na, _ := netip.AddrFromSlice(a.IP)
  37         na = na.WithZone(a.Zone)
  38         return netip.AddrPortFrom(na, uint16(a.Port))
  39 }
  40
  41 // Network returns the address's network name, "tcp".
  42 func (a *TCPAddr) Network() string { return "tcp" }
  43
  44 func (a *TCPAddr) String() string {
  45         if a == nil {
  46                 return "<nil>"
  47         }
  48         ip := ipEmptyString(a.IP)
  49         if a.Zone != "" {
  50                 return JoinHostPort(ip+"%"+a.Zone, itoa.Itoa(a.Port))
  51         }
  52         return JoinHostPort(ip, itoa.Itoa(a.Port))
  53 }
  54
  55 func (a *TCPAddr) isWildcard() bool {
  56         if a == nil || a.IP == nil {
  57                 return true
  58         }
  59         return a.IP.IsUnspecified()
  60 }
  61
  62 func (a *TCPAddr) opAddr() Addr {
  63         if a == nil {
  64                 return nil
  65         }
  66         return a
  67 }
  68
  69 // ResolveTCPAddr returns an address of TCP end point.
  70 //
  71 // The network must be a TCP network name.
  72 //
  73 // If the host in the address parameter is not a literal IP address or
  74 // the port is not a literal port number, ResolveTCPAddr resolves the
  75 // address to an address of TCP end point.
  76 // Otherwise, it parses the address as a pair of literal IP address
  77 // and port number.
  78 // The address parameter can use a host name, but this is not
  79 // recommended, because it will return at most one of the host name's
  80 // IP addresses.
  81 //
  82 // See func Dial for a description of the network and address
  83 // parameters.
  84 func ResolveTCPAddr(network, address string) (*TCPAddr, error) {
  85         switch network {
  86         case "tcp", "tcp4", "tcp6":
  87         case "": // a hint wildcard for Go 1.0 undocumented behavior
  88                 network = "tcp"
  89         default:
  90                 return nil, UnknownNetworkError(network)
  91         }
  92         addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
  93         if err != nil {
  94                 return nil, err
  95         }
  96         return addrs.forResolve(network, address).(*TCPAddr), nil
  97 }
  98
  99 // TCPAddrFromAddrPort returns addr as a TCPAddr. If addr.IsValid() is false,
 100 // then the returned TCPAddr will contain a nil IP field, indicating an
 101 // address family-agnostic unspecified address.
 102 func TCPAddrFromAddrPort(addr netip.AddrPort) *TCPAddr {
 103         return &TCPAddr{
 104                 IP:   addr.Addr().AsSlice(),
 105                 Zone: addr.Addr().Zone(),
 106                 Port: int(addr.Port()),
 107         }
 108 }
 109
 110 // TCPConn is an implementation of the Conn interface for TCP network
 111 // connections.
 112 type TCPConn struct {
 113         conn
 114 }
 115
 116 // SyscallConn returns a raw network connection.
 117 // This implements the syscall.Conn interface.
 118 func (c *TCPConn) SyscallConn() (syscall.RawConn, error) {
 119         if !c.ok() {
 120                 return nil, syscall.EINVAL
 121         }
 122         return newRawConn(c.fd)
 123 }
 124
 125 // ReadFrom implements the io.ReaderFrom ReadFrom method.
 126 func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
 127         if !c.ok() {
 128                 return 0, syscall.EINVAL
 129         }
 130         n, err := c.readFrom(r)
 131         if err != nil && err != io.EOF {
 132                 err = &OpError{Op: "readfrom", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 133         }
 134         return n, err
 135 }
 136
 137 // CloseRead shuts down the reading side of the TCP connection.
 138 // Most callers should just use Close.
 139 func (c *TCPConn) CloseRead() error {
 140         if !c.ok() {
 141                 return syscall.EINVAL
 142         }
 143         if err := c.fd.closeRead(); err != nil {
 144                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 145         }
 146         return nil
 147 }
 148
 149 // CloseWrite shuts down the writing side of the TCP connection.
 150 // Most callers should just use Close.
 151 func (c *TCPConn) CloseWrite() error {
 152         if !c.ok() {
 153                 return syscall.EINVAL
 154         }
 155         if err := c.fd.closeWrite(); err != nil {
 156                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 157         }
 158         return nil
 159 }
 160
 161 // SetLinger sets the behavior of Close on a connection which still
 162 // has data waiting to be sent or to be acknowledged.
 163 //
 164 // If sec < 0 (the default), the operating system finishes sending the
 165 // data in the background.
 166 //
 167 // If sec == 0, the operating system discards any unsent or
 168 // unacknowledged data.
 169 //
 170 // If sec > 0, the data is sent in the background as with sec < 0. On
 171 // some operating systems after sec seconds have elapsed any remaining
 172 // unsent data may be discarded.
 173 func (c *TCPConn) SetLinger(sec int) error {
 174         if !c.ok() {
 175                 return syscall.EINVAL
 176         }
 177         if err := setLinger(c.fd, sec); err != nil {
 178                 return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 179         }
 180         return nil
 181 }
 182
 183 // SetKeepAlive sets whether the operating system should send
 184 // keep-alive messages on the connection.
 185 func (c *TCPConn) SetKeepAlive(keepalive bool) error {
 186         if !c.ok() {
 187                 return syscall.EINVAL
 188         }
 189         if err := setKeepAlive(c.fd, keepalive); err != nil {
 190                 return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 191         }
 192         return nil
 193 }
 194
 195 // SetKeepAlivePeriod sets period between keep-alives.
 196 func (c *TCPConn) SetKeepAlivePeriod(d time.Duration) error {
 197         if !c.ok() {
 198                 return syscall.EINVAL
 199         }
 200         if err := setKeepAlivePeriod(c.fd, d); err != nil {
 201                 return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 202         }
 203         return nil
 204 }
 205
 206 // SetNoDelay controls whether the operating system should delay
 207 // packet transmission in hopes of sending fewer packets (Nagle's
 208 // algorithm).  The default is true (no delay), meaning that data is
 209 // sent as soon as possible after a Write.
 210 func (c *TCPConn) SetNoDelay(noDelay bool) error {
 211         if !c.ok() {
 212                 return syscall.EINVAL
 213         }
 214         if err := setNoDelay(c.fd, noDelay); err != nil {
 215                 return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 216         }
 217         return nil
 218 }
 219
 220 func newTCPConn(fd *netFD) *TCPConn {
 221         c := &TCPConn{conn{fd}}
 222         setNoDelay(c.fd, true)
 223         return c
 224 }
 225
 226 // DialTCP acts like Dial for TCP networks.
 227 //
 228 // The network must be a TCP network name; see func Dial for details.
 229 //
 230 // If laddr is nil, a local address is automatically chosen.
 231 // If the IP field of raddr is nil or an unspecified IP address, the
 232 // local system is assumed.
 233 func DialTCP(network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
 234         switch network {
 235         case "tcp", "tcp4", "tcp6":
 236         default:
 237                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
 238         }
 239         if raddr == nil {
 240                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
 241         }
 242         sd := &sysDialer{network: network, address: raddr.String()}
 243         c, err := sd.dialTCP(context.Background(), laddr, raddr)
 244         if err != nil {
 245                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 246         }
 247         return c, nil
 248 }
 249
 250 // TCPListener is a TCP network listener. Clients should typically
 251 // use variables of type Listener instead of assuming TCP.
 252 type TCPListener struct {
 253         fd *netFD
 254         lc ListenConfig
 255 }
 256
 257 // SyscallConn returns a raw network connection.
 258 // This implements the syscall.Conn interface.
 259 //
 260 // The returned RawConn only supports calling Control. Read and
 261 // Write return an error.
 262 func (l *TCPListener) SyscallConn() (syscall.RawConn, error) {
 263         if !l.ok() {
 264                 return nil, syscall.EINVAL
 265         }
 266         return newRawListener(l.fd)
 267 }
 268
 269 // AcceptTCP accepts the next incoming call and returns the new
 270 // connection.
 271 func (l *TCPListener) AcceptTCP() (*TCPConn, error) {
 272         if !l.ok() {
 273                 return nil, syscall.EINVAL
 274         }
 275         c, err := l.accept()
 276         if err != nil {
 277                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 278         }
 279         return c, nil
 280 }
 281
 282 // Accept implements the Accept method in the Listener interface; it
 283 // waits for the next call and returns a generic Conn.
 284 func (l *TCPListener) Accept() (Conn, error) {
 285         if !l.ok() {
 286                 return nil, syscall.EINVAL
 287         }
 288         c, err := l.accept()
 289         if err != nil {
 290                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 291         }
 292         return c, nil
 293 }
 294
 295 // Close stops listening on the TCP address.
 296 // Already Accepted connections are not closed.
 297 func (l *TCPListener) Close() error {
 298         if !l.ok() {
 299                 return syscall.EINVAL
 300         }
 301         if err := l.close(); err != nil {
 302                 return &OpError{Op: "close", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 303         }
 304         return nil
 305 }
 306
 307 // Addr returns the listener's network address, a *TCPAddr.
 308 // The Addr returned is shared by all invocations of Addr, so
 309 // do not modify it.
 310 func (l *TCPListener) Addr() Addr { return l.fd.laddr }
 311
 312 // SetDeadline sets the deadline associated with the listener.
 313 // A zero time value disables the deadline.
 314 func (l *TCPListener) SetDeadline(t time.Time) error {
 315         if !l.ok() {
 316                 return syscall.EINVAL
 317         }
 318         if err := l.fd.pfd.SetDeadline(t); err != nil {
 319                 return &OpError{Op: "set", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 320         }
 321         return nil
 322 }
 323
 324 // File returns a copy of the underlying os.File.
 325 // It is the caller's responsibility to close f when finished.
 326 // Closing l does not affect f, and closing f does not affect l.
 327 //
 328 // The returned os.File's file descriptor is different from the
 329 // connection's. Attempting to change properties of the original
 330 // using this duplicate may or may not have the desired effect.
 331 func (l *TCPListener) File() (f *os.File, err error) {
 332         if !l.ok() {
 333                 return nil, syscall.EINVAL
 334         }
 335         f, err = l.file()
 336         if err != nil {
 337                 return nil, &OpError{Op: "file", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 338         }
 339         return
 340 }
 341
 342 // ListenTCP acts like Listen for TCP networks.
 343 //
 344 // The network must be a TCP network name; see func Dial for details.
 345 //
 346 // If the IP field of laddr is nil or an unspecified IP address,
 347 // ListenTCP listens on all available unicast and anycast IP addresses
 348 // of the local system.
 349 // If the Port field of laddr is 0, a port number is automatically
 350 // chosen.
 351 func ListenTCP(network string, laddr *TCPAddr) (*TCPListener, error) {
 352         switch network {
 353         case "tcp", "tcp4", "tcp6":
 354         default:
 355                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
 356         }
 357         if laddr == nil {
 358                 laddr = &TCPAddr{}
 359         }
 360         sl := &sysListener{network: network, address: laddr.String()}
 361         ln, err := sl.listenTCP(context.Background(), laddr)
 362         if err != nil {
 363                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
 364         }
 365         return ln, nil
 366 }
 367
 368 // roundDurationUp rounds d to the next multiple of to.
 369 func roundDurationUp(d time.Duration, to time.Duration) time.Duration {
 370         return (d + to - 1) / to
 371 }