Gecko [ waterstats.dev.bestseocompanymiami.com ]

Name	Size	Permission
http	[ DIR ]	drwxr-xr-x
internal	[ DIR ]	drwxr-xr-x
mail	[ DIR ]	drwxr-xr-x
netip	[ DIR ]	drwxr-xr-x
rpc	[ DIR ]	drwxr-xr-x
smtp	[ DIR ]	drwxr-xr-x
testdata	[ DIR ]	drwxr-xr-x
textproto	[ DIR ]	drwxr-xr-x
url	[ DIR ]	drwxr-xr-x
addrselect.go	9.69 KB	-rw-r--r--
addrselect_test.go	8.5 KB	-rw-r--r--
cgo_aix.go	582 B	-rw-r--r--
cgo_android.go	272 B	-rw-r--r--
cgo_bsd.go	343 B	-rw-r--r--
cgo_darwin.go	298 B	-rw-r--r--
cgo_linux.go	642 B	-rw-r--r--
cgo_netbsd.go	276 B	-rw-r--r--
cgo_openbsd.go	276 B	-rw-r--r--
cgo_resnew.go	580 B	-rw-r--r--
cgo_resold.go	579 B	-rw-r--r--
cgo_socknew.go	753 B	-rw-r--r--
cgo_sockold.go	842 B	-rw-r--r--
cgo_solaris.go	343 B	-rw-r--r--
cgo_stub.go	1.33 KB	-rw-r--r--
cgo_unix.go	11.42 KB	-rw-r--r--
cgo_unix_cgo.go	2.24 KB	-rw-r--r--
cgo_unix_cgo_res.go	892 B	-rw-r--r--
cgo_unix_cgo_resn.go	979 B	-rw-r--r--
cgo_unix_syscall.go	3 KB	-rw-r--r--
cgo_unix_test.go	1.44 KB	-rw-r--r--
conf.go	15.48 KB	-rw-r--r--
conf_test.go	12.29 KB	-rw-r--r--
conn_test.go	1.82 KB	-rw-r--r--
dial.go	26.85 KB	-rw-r--r--
dial_test.go	30.28 KB	-rw-r--r--
dial_unix_test.go	2.77 KB	-rw-r--r--
dnsclient.go	5.67 KB	-rw-r--r--
dnsclient_test.go	1.51 KB	-rw-r--r--
dnsclient_unix.go	24.66 KB	-rw-r--r--
dnsclient_unix_test.go	72.77 KB	-rw-r--r--
dnsconfig.go	2.19 KB	-rw-r--r--
dnsconfig_unix.go	4.12 KB	-rw-r--r--
dnsconfig_unix_test.go	7.07 KB	-rw-r--r--
dnsconfig_windows.go	1.61 KB	-rw-r--r--
dnsname_test.go	1.96 KB	-rw-r--r--
error_plan9.go	224 B	-rw-r--r--
error_plan9_test.go	437 B	-rw-r--r--
error_posix.go	543 B	-rw-r--r--
error_posix_test.go	981 B	-rw-r--r--
error_test.go	20.32 KB	-rw-r--r--
error_unix.go	382 B	-rw-r--r--
error_unix_test.go	723 B	-rw-r--r--
error_windows.go	355 B	-rw-r--r--
error_windows_test.go	757 B	-rw-r--r--
example_test.go	8.45 KB	-rw-r--r--
external_test.go	4.05 KB	-rw-r--r--
fd_fake.go	3.79 KB	-rw-r--r--
fd_js.go	627 B	-rw-r--r--
fd_plan9.go	3.56 KB	-rw-r--r--
fd_posix.go	4.29 KB	-rw-r--r--
fd_unix.go	5.43 KB	-rw-r--r--
fd_wasip1.go	496 B	-rw-r--r--
fd_windows.go	6.21 KB	-rw-r--r--
file.go	1.69 KB	-rw-r--r--
file_plan9.go	2.77 KB	-rw-r--r--
file_stub.go	481 B	-rw-r--r--
file_test.go	6.43 KB	-rw-r--r--
file_unix.go	2.55 KB	-rw-r--r--
file_unix_test.go	2.07 KB	-rw-r--r--
file_wasip1.go	2.2 KB	-rw-r--r--
file_wasip1_test.go	3.76 KB	-rw-r--r--
file_windows.go	521 B	-rw-r--r--
hook.go	934 B	-rw-r--r--
hook_plan9.go	211 B	-rw-r--r--
hook_unix.go	658 B	-rw-r--r--
hook_windows.go	720 B	-rw-r--r--
hosts.go	3.48 KB	-rw-r--r--
hosts_test.go	5.6 KB	-rw-r--r--
interface.go	7.57 KB	-rw-r--r--
interface_aix.go	4.46 KB	-rw-r--r--
interface_bsd.go	2.82 KB	-rw-r--r--
interface_bsd_test.go	1.44 KB	-rw-r--r--
interface_bsdvar.go	718 B	-rw-r--r--
interface_darwin.go	1.29 KB	-rw-r--r--
interface_freebsd.go	1.29 KB	-rw-r--r--
interface_linux.go	6.96 KB	-rw-r--r--
interface_linux_test.go	3.65 KB	-rw-r--r--
interface_plan9.go	4.74 KB	-rw-r--r--
interface_solaris.go	2.13 KB	-rw-r--r--
interface_stub.go	814 B	-rw-r--r--
interface_test.go	9.76 KB	-rw-r--r--
interface_unix_test.go	4.85 KB	-rw-r--r--
interface_windows.go	5.49 KB	-rw-r--r--
ip.go	13.97 KB	-rw-r--r--
ip_test.go	25.69 KB	-rw-r--r--
iprawsock.go	7.11 KB	-rw-r--r--
iprawsock_plan9.go	874 B	-rw-r--r--
iprawsock_posix.go	3.89 KB	-rw-r--r--
iprawsock_test.go	5.98 KB	-rw-r--r--
ipsock.go	9.43 KB	-rw-r--r--
ipsock_plan9.go	7.48 KB	-rw-r--r--
ipsock_plan9_test.go	645 B	-rw-r--r--
ipsock_posix.go	8.62 KB	-rw-r--r--
ipsock_test.go	6.81 KB	-rw-r--r--
listen_test.go	20.5 KB	-rw-r--r--
lookup.go	28.6 KB	-rw-r--r--
lookup_plan9.go	9.89 KB	-rw-r--r--
lookup_test.go	41.45 KB	-rw-r--r--
lookup_unix.go	3.35 KB	-rw-r--r--
lookup_windows.go	14.19 KB	-rw-r--r--
lookup_windows_test.go	8.7 KB	-rw-r--r--
mac.go	1.88 KB	-rw-r--r--
mac_test.go	3.26 KB	-rw-r--r--
main_cloexec_test.go	693 B	-rw-r--r--
main_conf_test.go	2.45 KB	-rw-r--r--
main_plan9_test.go	392 B	-rw-r--r--
main_posix_test.go	1.37 KB	-rw-r--r--
main_test.go	7.53 KB	-rw-r--r--
main_unix_test.go	1.19 KB	-rw-r--r--
main_wasm_test.go	284 B	-rw-r--r--
main_windows_test.go	1 KB	-rw-r--r--
mockserver_test.go	13.28 KB	-rw-r--r--
mptcpsock_linux.go	3.96 KB	-rw-r--r--
mptcpsock_linux_test.go	4.06 KB	-rw-r--r--
mptcpsock_stub.go	542 B	-rw-r--r--
net.go	27.12 KB	-rw-r--r--
net_fake.go	26.45 KB	-rw-r--r--
net_fake_test.go	2.79 KB	-rw-r--r--
net_test.go	13.3 KB	-rw-r--r--
net_windows_test.go	16.28 KB	-rw-r--r--
netcgo_off.go	222 B	-rw-r--r--
netcgo_on.go	220 B	-rw-r--r--
netgo_netcgo.go	453 B	-rw-r--r--
netgo_off.go	220 B	-rw-r--r--
netgo_on.go	218 B	-rw-r--r--
nss.go	5.48 KB	-rw-r--r--
nss_test.go	3.4 KB	-rw-r--r--
packetconn_test.go	3.02 KB	-rw-r--r--
parse.go	5.66 KB	-rw-r--r--
parse_test.go	1.65 KB	-rw-r--r--
pipe.go	5.43 KB	-rw-r--r--
pipe_test.go	1.2 KB	-rw-r--r--
platform_test.go	4.33 KB	-rw-r--r--
port.go	1.46 KB	-rw-r--r--
port_test.go	1.34 KB	-rw-r--r--
port_unix.go	1.24 KB	-rw-r--r--
protoconn_test.go	7.44 KB	-rw-r--r--
rawconn.go	2.7 KB	-rw-r--r--
rawconn_stub_test.go	631 B	-rw-r--r--
rawconn_test.go	4.33 KB	-rw-r--r--
rawconn_unix_test.go	2.96 KB	-rw-r--r--
rawconn_windows_test.go	3.12 KB	-rw-r--r--
resolverdialfunc_test.go	8.25 KB	-rw-r--r--
rlimit_js.go	346 B	-rw-r--r--
rlimit_unix.go	1.1 KB	-rw-r--r--
sendfile_linux.go	1.15 KB	-rw-r--r--
sendfile_stub.go	403 B	-rw-r--r--
sendfile_test.go	12.06 KB	-rw-r--r--
sendfile_unix_alt.go	2.27 KB	-rw-r--r--
sendfile_windows.go	1.05 KB	-rw-r--r--
server_test.go	11.67 KB	-rw-r--r--
sock_bsd.go	918 B	-rw-r--r--
sock_cloexec.go	730 B	-rw-r--r--
sock_cloexec_solaris.go	1.43 KB	-rw-r--r--
sock_linux.go	993 B	-rw-r--r--
sock_linux_test.go	575 B	-rw-r--r--
sock_plan9.go	262 B	-rw-r--r--
sock_posix.go	6.29 KB	-rw-r--r--
sock_stub.go	390 B	-rw-r--r--
sock_windows.go	802 B	-rw-r--r--
sockaddr_posix.go	1.45 KB	-rw-r--r--
sockopt_aix.go	1.43 KB	-rw-r--r--
sockopt_bsd.go	2.21 KB	-rw-r--r--
sockopt_fake.go	955 B	-rw-r--r--
sockopt_linux.go	1.25 KB	-rw-r--r--
sockopt_plan9.go	406 B	-rw-r--r--
sockopt_posix.go	2.13 KB	-rw-r--r--
sockopt_solaris.go	1.25 KB	-rw-r--r--
sockopt_windows.go	1.51 KB	-rw-r--r--
sockoptip_bsdvar.go	867 B	-rw-r--r--
sockoptip_linux.go	735 B	-rw-r--r--
sockoptip_posix.go	1.38 KB	-rw-r--r--
sockoptip_stub.go	769 B	-rw-r--r--
sockoptip_windows.go	786 B	-rw-r--r--
splice_linux.go	1.71 KB	-rw-r--r--
splice_linux_test.go	14.49 KB	-rw-r--r--
splice_stub.go	376 B	-rw-r--r--
sys_cloexec.go	962 B	-rw-r--r--
tcpconn_keepalive_conf_darwin_...	430 B	-rw-r--r--
tcpconn_keepalive_conf_posix_t...	1.55 KB	-rw-r--r--
tcpconn_keepalive_conf_solaris...	1.77 KB	-rw-r--r--
tcpconn_keepalive_conf_unix_te...	490 B	-rw-r--r--
tcpconn_keepalive_conf_windows...	987 B	-rw-r--r--
tcpconn_keepalive_illumos_test...	3.98 KB	-rw-r--r--
tcpconn_keepalive_posix_test.g...	2.52 KB	-rw-r--r--
tcpconn_keepalive_solaris_test...	5.67 KB	-rw-r--r--
tcpconn_keepalive_test.go	4.15 KB	-rw-r--r--
tcpsock.go	13.67 KB	-rw-r--r--
tcpsock_plan9.go	2.3 KB	-rw-r--r--
tcpsock_posix.go	6.27 KB	-rw-r--r--
tcpsock_solaris.go	1.32 KB	-rw-r--r--
tcpsock_test.go	17.68 KB	-rw-r--r--
tcpsock_unix.go	1.05 KB	-rw-r--r--
tcpsock_unix_test.go	2.34 KB	-rw-r--r--
tcpsock_windows.go	1.31 KB	-rw-r--r--
tcpsockopt_darwin.go	1.4 KB	-rw-r--r--
tcpsockopt_openbsd.go	759 B	-rw-r--r--
tcpsockopt_plan9.go	762 B	-rw-r--r--
tcpsockopt_posix.go	442 B	-rw-r--r--
tcpsockopt_solaris.go	3.35 KB	-rw-r--r--
tcpsockopt_stub.go	570 B	-rw-r--r--
tcpsockopt_unix.go	1.32 KB	-rw-r--r--
tcpsockopt_windows.go	3.76 KB	-rw-r--r--
timeout_test.go	30.01 KB	-rw-r--r--
udpsock.go	11.83 KB	-rw-r--r--
udpsock_plan9.go	4.64 KB	-rw-r--r--
udpsock_plan9_test.go	1.31 KB	-rw-r--r--
udpsock_posix.go	7.53 KB	-rw-r--r--
udpsock_test.go	17.24 KB	-rw-r--r--
unixsock.go	10.12 KB	-rw-r--r--
unixsock_linux_test.go	2.29 KB	-rw-r--r--
unixsock_plan9.go	1.24 KB	-rw-r--r--
unixsock_posix.go	6.64 KB	-rw-r--r--
unixsock_readmsg_cloexec.go	654 B	-rw-r--r--
unixsock_readmsg_cmsg_cloexec....	332 B	-rw-r--r--
unixsock_readmsg_other.go	275 B	-rw-r--r--
unixsock_readmsg_test.go	2.51 KB	-rw-r--r--
unixsock_test.go	10.64 KB	-rw-r--r--
unixsock_windows_test.go	1.83 KB	-rw-r--r--
write_unix_test.go	1.61 KB	-rw-r--r--
writev_test.go	5.03 KB	-rw-r--r--
writev_unix.go	666 B	-rw-r--r--

Code Editor : tcpsock.go

// 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"
	"internal/itoa"
	"io"
	"net/netip"
	"os"
	"syscall"
	"time"
)

// BUG(mikio): On JS and Windows, the File method of TCPConn and
// 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
}

// AddrPort returns the [TCPAddr] a as a [netip.AddrPort].
//
// If a.Port does not fit in a uint16, it's silently truncated.
//
// If a is nil, a zero value is returned.
func (a *TCPAddr) AddrPort() netip.AddrPort {
	if a == nil {
		return netip.AddrPort{}
	}
	na, _ := netip.AddrFromSlice(a.IP)
	na = na.WithZone(a.Zone)
	return netip.AddrPortFrom(na, uint16(a.Port))
}

// 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.Itoa(a.Port))
	}
	return JoinHostPort(ip, itoa.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 returns an address of TCP end point.
//
// The network must be a TCP network name.
//
// If the host in the address parameter is not a literal IP address or
// the port is not a literal port number, ResolveTCPAddr resolves the
// address to an address of TCP end point.
// Otherwise, it parses the address as a pair of literal IP address
// and port number.
// The address parameter can use a host name, but this is not
// recommended, because it will return at most one of the host name's
// IP addresses.
//
// See func [Dial] for a description of the network and address
// parameters.
func ResolveTCPAddr(network, address string) (*TCPAddr, error) {
	switch network {
	case "tcp", "tcp4", "tcp6":
	case "": // a hint wildcard for Go 1.0 undocumented behavior
		network = "tcp"
	default:
		return nil, UnknownNetworkError(network)
	}
	addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
	if err != nil {
		return nil, err
	}
	return addrs.forResolve(network, address).(*TCPAddr), nil
}

// TCPAddrFromAddrPort returns addr as a [TCPAddr]. If addr.IsValid() is false,
// then the returned TCPAddr will contain a nil IP field, indicating an
// address family-agnostic unspecified address.
func TCPAddrFromAddrPort(addr netip.AddrPort) *TCPAddr {
	return &TCPAddr{
		IP:   addr.Addr().AsSlice(),
		Zone: addr.Addr().Zone(),
		Port: int(addr.Port()),
	}
}

// TCPConn is an implementation of the [Conn] interface for TCP network
// connections.
type TCPConn struct {
	conn
}

// KeepAliveConfig contains TCP keep-alive options.
//
// If the Idle, Interval, or Count fields are zero, a default value is chosen.
// If a field is negative, the corresponding socket-level option will be left unchanged.
//
// Note that prior to Windows 10 version 1709, neither setting Idle and Interval
// separately nor changing Count (which is usually 10) is supported.
// Therefore, it's recommended to set both Idle and Interval to non-negative values
// in conjunction with a -1 for Count on those old Windows if you intend to customize
// the TCP keep-alive settings.
// By contrast, if only one of Idle and Interval is set to a non-negative value,
// the other will be set to the system default value, and ultimately,
// set both Idle and Interval to negative values if you want to leave them unchanged.
//
// Note that Solaris and its derivatives do not support setting Interval to a non-negative value
// and Count to a negative value, or vice-versa.
type KeepAliveConfig struct {
	// If Enable is true, keep-alive probes are enabled.
	Enable bool

// Idle is the time that the connection must be idle before
	// the first keep-alive probe is sent.
	// If zero, a default value of 15 seconds is used.
	Idle time.Duration

// Interval is the time between keep-alive probes.
	// If zero, a default value of 15 seconds is used.
	Interval time.Duration

// Count is the maximum number of keep-alive probes that
	// can go unanswered before dropping a connection.
	// If zero, a default value of 9 is used.
	Count int
}

// SyscallConn returns a raw network connection.
// This implements the [syscall.Conn] interface.
func (c *TCPConn) SyscallConn() (syscall.RawConn, error) {
	if !c.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(c.fd), nil
}

// 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
}

// WriteTo implements the io.WriterTo WriteTo method.
func (c *TCPConn) WriteTo(w io.Writer) (int64, error) {
	if !c.ok() {
		return 0, syscall.EINVAL
	}
	n, err := c.writeTo(w)
	if err != nil && err != io.EOF {
		err = &OpError{Op: "writeto", 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 including Linux, this may cause Close to block
// until all data has been sent or discarded.
// 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
// keep-alive 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 the duration the connection needs to
// remain idle before TCP starts sending keepalive probes.
//
// Note that calling this method on Windows prior to Windows 10 version 1709
// will reset the KeepAliveInterval to the default system value, which is normally 1 second.
func (c *TCPConn) SetKeepAlivePeriod(d time.Duration) error {
	if !c.ok() {
		return syscall.EINVAL
	}
	if err := setKeepAliveIdle(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
}

// MultipathTCP reports whether the ongoing connection is using MPTCP.
//
// If Multipath TCP is not supported by the host, by the other peer or
// intentionally / accidentally filtered out by a device in between, a
// fallback to TCP will be done. This method does its best to check if
// MPTCP is still being used or not.
//
// On Linux, more conditions are verified on kernels >= v5.16, improving
// the results.
func (c *TCPConn) MultipathTCP() (bool, error) {
	if !c.ok() {
		return false, syscall.EINVAL
	}
	return isUsingMultipathTCP(c.fd), nil
}

func newTCPConn(fd *netFD, keepAliveIdle time.Duration, keepAliveCfg KeepAliveConfig, preKeepAliveHook func(*netFD), keepAliveHook func(KeepAliveConfig)) *TCPConn {
	setNoDelay(fd, true)
	if !keepAliveCfg.Enable && keepAliveIdle >= 0 {
		keepAliveCfg = KeepAliveConfig{
			Enable: true,
			Idle:   keepAliveIdle,
		}
	}
	c := &TCPConn{conn{fd}}
	if keepAliveCfg.Enable {
		if preKeepAliveHook != nil {
			preKeepAliveHook(fd)
		}
		c.SetKeepAliveConfig(keepAliveCfg)
		if keepAliveHook != nil {
			keepAliveHook(keepAliveCfg)
		}
	}
	return c
}

// DialTCP acts like [Dial] for TCP networks.
//
// The network must be a TCP network name; see func Dial for details.
//
// If laddr is nil, a local address is automatically chosen.
// If the IP field of raddr is nil or an unspecified IP address, the
// local system is assumed.
func DialTCP(network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
	switch network {
	case "tcp", "tcp4", "tcp6":
	default:
		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
	}
	if raddr == nil {
		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
	}
	sd := &sysDialer{network: network, address: raddr.String()}
	c, err := sd.dialTCP(context.Background(), laddr, raddr)
	if err != nil {
		return nil, &OpError{Op: "dial", Net: network, 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
	lc ListenConfig
}

// SyscallConn returns a raw network connection.
// This implements the [syscall.Conn] interface.
//
// The returned RawConn only supports calling Control. Read and
// Write return an error.
func (l *TCPListener) SyscallConn() (syscall.RawConn, error) {
	if !l.ok() {
		return nil, syscall.EINVAL
	}
	return newRawListener(l.fd), nil
}

// 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
	}
	return l.fd.SetDeadline(t)
}

// File returns a copy of the underlying [os.File].
// 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 acts like [Listen] for TCP networks.
//
// The network must be a TCP network name; see func Dial for details.
//
// If the IP field of laddr is nil or an unspecified IP address,
// ListenTCP listens on all available unicast and anycast IP addresses
// of the local system.
// If the Port field of laddr is 0, a port number is automatically
// chosen.
func ListenTCP(network string, laddr *TCPAddr) (*TCPListener, error) {
	switch network {
	case "tcp", "tcp4", "tcp6":
	default:
		return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
	}
	if laddr == nil {
		laddr = &TCPAddr{}
	}
	sl := &sysListener{network: network, address: laddr.String()}
	ln, err := sl.listenTCP(context.Background(), laddr)
	if err != nil {
		return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
	}
	return ln, nil
}

// roundDurationUp rounds d to the next multiple of to.
func roundDurationUp(d time.Duration, to time.Duration) time.Duration {
	return (d + to - 1) / to
}

${this.title}

Code Editor : tcpsock.go