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// Copyright 2010 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 (
"errors"
"time"
)
// A Dialer contains options for connecting to an address.
//
// The zero value for each field is equivalent to dialing
// without that option. Dialing with the zero value of Dialer
// is therefore equivalent to just calling the Dial function.
type Dialer struct {
// Timeout is the maximum amount of time a dial will wait for
// a connect to complete. If Deadline is also set, it may fail
// earlier.
//
// The default is no timeout.
//
// With or without a timeout, the operating system may impose
// its own earlier timeout. For instance, TCP timeouts are
// often around 3 minutes.
Timeout time.Duration
// Deadline is the absolute point in time after which dials
// will fail. If Timeout is set, it may fail earlier.
// Zero means no deadline, or dependent on the operating system
// as with the Timeout option.
Deadline time.Time
// LocalAddr is the local address to use when dialing an
// address. The address must be of a compatible type for the
// network being dialed.
// If nil, a local address is automatically chosen.
LocalAddr Addr
}
// Return either now+Timeout or Deadline, whichever comes first.
// Or zero, if neither is set.
func (d *Dialer) deadline() time.Time {
if d.Timeout == 0 {
return d.Deadline
}
timeoutDeadline := time.Now().Add(d.Timeout)
if d.Deadline.IsZero() || timeoutDeadline.Before(d.Deadline) {
return timeoutDeadline
} else {
return d.Deadline
}
}
func parseNetwork(net string) (afnet string, proto int, err error) {
i := last(net, ':')
if i < 0 { // no colon
switch net {
case "tcp", "tcp4", "tcp6":
case "udp", "udp4", "udp6":
case "ip", "ip4", "ip6":
case "unix", "unixgram", "unixpacket":
default:
return "", 0, UnknownNetworkError(net)
}
return net, 0, nil
}
afnet = net[:i]
switch afnet {
case "ip", "ip4", "ip6":
protostr := net[i+1:]
proto, i, ok := dtoi(protostr, 0)
if !ok || i != len(protostr) {
proto, err = lookupProtocol(protostr)
if err != nil {
return "", 0, err
}
}
return afnet, proto, nil
}
return "", 0, UnknownNetworkError(net)
}
func resolveAddr(op, net, addr string, deadline time.Time) (Addr, error) {
afnet, _, err := parseNetwork(net)
if err != nil {
return nil, &OpError{op, net, nil, err}
}
if op == "dial" && addr == "" {
return nil, &OpError{op, net, nil, errMissingAddress}
}
switch afnet {
case "unix", "unixgram", "unixpacket":
return ResolveUnixAddr(afnet, addr)
}
return resolveInternetAddr(afnet, addr, deadline)
}
// Dial connects to the address on the named network.
//
// Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only),
// "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4"
// (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and
// "unixpacket".
//
// For TCP and UDP networks, addresses have the form host:port.
// If host is a literal IPv6 address or host name, it must be enclosed
// in square brackets as in "[::1]:80", "[ipv6-host]:http" or
// "[ipv6-host%zone]:80".
// The functions JoinHostPort and SplitHostPort manipulate addresses
// in this form.
//
// Examples:
// Dial("tcp", "12.34.56.78:80")
// Dial("tcp", "google.com:http")
// Dial("tcp", "[2001:db8::1]:http")
// Dial("tcp", "[fe80::1%lo0]:80")
//
// For IP networks, the network must be "ip", "ip4" or "ip6" followed
// by a colon and a protocol number or name and the addr must be a
// literal IP address.
//
// Examples:
// Dial("ip4:1", "127.0.0.1")
// Dial("ip6:ospf", "::1")
//
// For Unix networks, the address must be a file system path.
func Dial(network, address string) (Conn, error) {
var d Dialer
return d.Dial(network, address)
}
// DialTimeout acts like Dial but takes a timeout.
// The timeout includes name resolution, if required.
func DialTimeout(network, address string, timeout time.Duration) (Conn, error) {
d := Dialer{Timeout: timeout}
return d.Dial(network, address)
}
// Dial connects to the address on the named network.
//
// See func Dial for a description of the network and address
// parameters.
func (d *Dialer) Dial(network, address string) (Conn, error) {
return resolveAndDial(network, address, d.LocalAddr, d.deadline())
}
func dial(net, addr string, la, ra Addr, deadline time.Time) (c Conn, err error) {
if la != nil && la.Network() != ra.Network() {
return nil, &OpError{"dial", net, ra, errors.New("mismatched local addr type " + la.Network())}
}
switch ra := ra.(type) {
case *TCPAddr:
la, _ := la.(*TCPAddr)
c, err = dialTCP(net, la, ra, deadline)
case *UDPAddr:
la, _ := la.(*UDPAddr)
c, err = dialUDP(net, la, ra, deadline)
case *IPAddr:
la, _ := la.(*IPAddr)
c, err = dialIP(net, la, ra, deadline)
case *UnixAddr:
la, _ := la.(*UnixAddr)
c, err = dialUnix(net, la, ra, deadline)
default:
err = &OpError{"dial", net + " " + addr, ra, UnknownNetworkError(net)}
}
if err != nil {
return nil, err
}
return
}
type stringAddr struct {
net, addr string
}
func (a stringAddr) Network() string { return a.net }
func (a stringAddr) String() string { return a.addr }
// Listen announces on the local network address laddr.
// The network net must be a stream-oriented network: "tcp", "tcp4",
// "tcp6", "unix" or "unixpacket".
// See Dial for the syntax of laddr.
func Listen(net, laddr string) (Listener, error) {
la, err := resolveAddr("listen", net, laddr, noDeadline)
if err != nil {
return nil, err
}
switch la := la.(type) {
case *TCPAddr:
return ListenTCP(net, la)
case *UnixAddr:
return ListenUnix(net, la)
}
return nil, UnknownNetworkError(net)
}
// ListenPacket announces on the local network address laddr.
// The network net must be a packet-oriented network: "udp", "udp4",
// "udp6", "ip", "ip4", "ip6" or "unixgram".
// See Dial for the syntax of laddr.
func ListenPacket(net, laddr string) (PacketConn, error) {
la, err := resolveAddr("listen", net, laddr, noDeadline)
if err != nil {
return nil, err
}
switch la := la.(type) {
case *UDPAddr:
return ListenUDP(net, la)
case *IPAddr:
return ListenIP(net, la)
case *UnixAddr:
return ListenUnixgram(net, la)
}
return nil, UnknownNetworkError(net)
}
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