| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package net |
| |
| import ( |
| "context" |
| "io" |
| "os" |
| "syscall" |
| "time" |
| ) |
| |
| // BUG(mikio): On Windows, the File method of TCPListener is not |
| // implemented. |
| |
| // TCPAddr represents the address of a TCP end point. |
| type TCPAddr struct { |
| IP IP |
| Port int |
| Zone string // IPv6 scoped addressing zone |
| } |
| |
| // Network returns the address's network name, "tcp". |
| func (a *TCPAddr) Network() string { return "tcp" } |
| |
| func (a *TCPAddr) String() string { |
| if a == nil { |
| return "<nil>" |
| } |
| ip := ipEmptyString(a.IP) |
| if a.Zone != "" { |
| return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port)) |
| } |
| return JoinHostPort(ip, itoa(a.Port)) |
| } |
| |
| func (a *TCPAddr) isWildcard() bool { |
| if a == nil || a.IP == nil { |
| return true |
| } |
| return a.IP.IsUnspecified() |
| } |
| |
| func (a *TCPAddr) opAddr() Addr { |
| if a == nil { |
| return nil |
| } |
| return a |
| } |
| |
| // ResolveTCPAddr parses addr as a TCP address of the form "host:port" |
| // or "[ipv6-host%zone]:port" and resolves a pair of domain name and |
| // port name on the network net, which must be "tcp", "tcp4" or |
| // "tcp6". A literal address or host name for IPv6 must be enclosed |
| // in square brackets, as in "[::1]:80", "[ipv6-host]:http" or |
| // "[ipv6-host%zone]:80". |
| func ResolveTCPAddr(net, addr string) (*TCPAddr, error) { |
| switch net { |
| case "tcp", "tcp4", "tcp6": |
| case "": // a hint wildcard for Go 1.0 undocumented behavior |
| net = "tcp" |
| default: |
| return nil, UnknownNetworkError(net) |
| } |
| addrs, err := internetAddrList(context.Background(), net, addr) |
| if err != nil { |
| return nil, err |
| } |
| return addrs.first(isIPv4).(*TCPAddr), nil |
| } |
| |
| // TCPConn is an implementation of the Conn interface for TCP network |
| // connections. |
| type TCPConn struct { |
| conn |
| } |
| |
| // ReadFrom implements the io.ReaderFrom ReadFrom method. |
| func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) { |
| if !c.ok() { |
| return 0, syscall.EINVAL |
| } |
| n, err := c.readFrom(r) |
| if err != nil && err != io.EOF { |
| err = &OpError{Op: "readfrom", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return n, err |
| } |
| |
| // CloseRead shuts down the reading side of the TCP connection. |
| // Most callers should just use Close. |
| func (c *TCPConn) CloseRead() error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := c.fd.closeRead(); err != nil { |
| return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| // CloseWrite shuts down the writing side of the TCP connection. |
| // Most callers should just use Close. |
| func (c *TCPConn) CloseWrite() error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := c.fd.closeWrite(); err != nil { |
| return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| // SetLinger sets the behavior of Close on a connection which still |
| // has data waiting to be sent or to be acknowledged. |
| // |
| // If sec < 0 (the default), the operating system finishes sending the |
| // data in the background. |
| // |
| // If sec == 0, the operating system discards any unsent or |
| // unacknowledged data. |
| // |
| // If sec > 0, the data is sent in the background as with sec < 0. On |
| // some operating systems after sec seconds have elapsed any remaining |
| // unsent data may be discarded. |
| func (c *TCPConn) SetLinger(sec int) error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := setLinger(c.fd, sec); err != nil { |
| return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| // SetKeepAlive sets whether the operating system should send |
| // keepalive messages on the connection. |
| func (c *TCPConn) SetKeepAlive(keepalive bool) error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := setKeepAlive(c.fd, keepalive); err != nil { |
| return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| // SetKeepAlivePeriod sets period between keep alives. |
| func (c *TCPConn) SetKeepAlivePeriod(d time.Duration) error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := setKeepAlivePeriod(c.fd, d); err != nil { |
| return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| // SetNoDelay controls whether the operating system should delay |
| // packet transmission in hopes of sending fewer packets (Nagle's |
| // algorithm). The default is true (no delay), meaning that data is |
| // sent as soon as possible after a Write. |
| func (c *TCPConn) SetNoDelay(noDelay bool) error { |
| if !c.ok() { |
| return syscall.EINVAL |
| } |
| if err := setNoDelay(c.fd, noDelay); err != nil { |
| return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} |
| } |
| return nil |
| } |
| |
| func newTCPConn(fd *netFD) *TCPConn { |
| c := &TCPConn{conn{fd}} |
| setNoDelay(c.fd, true) |
| return c |
| } |
| |
| // DialTCP connects to the remote address raddr on the network net, |
| // which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is |
| // used as the local address for the connection. |
| func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) { |
| switch net { |
| case "tcp", "tcp4", "tcp6": |
| default: |
| return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)} |
| } |
| if raddr == nil { |
| return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress} |
| } |
| c, err := dialTCP(context.Background(), net, laddr, raddr) |
| if err != nil { |
| return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err} |
| } |
| return c, nil |
| } |
| |
| // TCPListener is a TCP network listener. Clients should typically |
| // use variables of type Listener instead of assuming TCP. |
| type TCPListener struct { |
| fd *netFD |
| } |
| |
| // AcceptTCP accepts the next incoming call and returns the new |
| // connection. |
| func (l *TCPListener) AcceptTCP() (*TCPConn, error) { |
| if !l.ok() { |
| return nil, syscall.EINVAL |
| } |
| c, err := l.accept() |
| if err != nil { |
| return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err} |
| } |
| return c, nil |
| } |
| |
| // Accept implements the Accept method in the Listener interface; it |
| // waits for the next call and returns a generic Conn. |
| func (l *TCPListener) Accept() (Conn, error) { |
| if !l.ok() { |
| return nil, syscall.EINVAL |
| } |
| c, err := l.accept() |
| if err != nil { |
| return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err} |
| } |
| return c, nil |
| } |
| |
| // Close stops listening on the TCP address. |
| // Already Accepted connections are not closed. |
| func (l *TCPListener) Close() error { |
| if !l.ok() { |
| return syscall.EINVAL |
| } |
| if err := l.close(); err != nil { |
| return &OpError{Op: "close", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err} |
| } |
| return nil |
| } |
| |
| // Addr returns the listener's network address, a *TCPAddr. |
| // The Addr returned is shared by all invocations of Addr, so |
| // do not modify it. |
| func (l *TCPListener) Addr() Addr { return l.fd.laddr } |
| |
| // SetDeadline sets the deadline associated with the listener. |
| // A zero time value disables the deadline. |
| func (l *TCPListener) SetDeadline(t time.Time) error { |
| if !l.ok() { |
| return syscall.EINVAL |
| } |
| if err := l.fd.setDeadline(t); err != nil { |
| return &OpError{Op: "set", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err} |
| } |
| return nil |
| } |
| |
| // File returns a copy of the underlying os.File, set to blocking |
| // mode. It is the caller's responsibility to close f when finished. |
| // Closing l does not affect f, and closing f does not affect l. |
| // |
| // The returned os.File's file descriptor is different from the |
| // connection's. Attempting to change properties of the original |
| // using this duplicate may or may not have the desired effect. |
| func (l *TCPListener) File() (f *os.File, err error) { |
| if !l.ok() { |
| return nil, syscall.EINVAL |
| } |
| f, err = l.file() |
| if err != nil { |
| return nil, &OpError{Op: "file", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err} |
| } |
| return |
| } |
| |
| // ListenTCP announces on the TCP address laddr and returns a TCP |
| // listener. Net must be "tcp", "tcp4", or "tcp6". If laddr has a |
| // port of 0, ListenTCP will choose an available port. The caller can |
| // use the Addr method of TCPListener to retrieve the chosen address. |
| func ListenTCP(net string, laddr *TCPAddr) (*TCPListener, error) { |
| switch net { |
| case "tcp", "tcp4", "tcp6": |
| default: |
| return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)} |
| } |
| if laddr == nil { |
| laddr = &TCPAddr{} |
| } |
| ln, err := listenTCP(context.Background(), net, laddr) |
| if err != nil { |
| return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: err} |
| } |
| return ln, nil |
| } |