c2047754c3
Compiler changes: * Change map assignment to use mapassign and assign value directly. * Change string iteration to use decoderune, faster for ASCII strings. * Change makeslice to take int, and use makeslice64 for larger values. * Add new noverflow field to hmap struct used for maps. Unresolved problems, to be fixed later: * Commented out test in go/types/sizes_test.go that doesn't compile. * Commented out reflect.TestStructOf test for padding after zero-sized field. Reviewed-on: https://go-review.googlesource.com/35231 gotools/: Updates for Go 1.8rc1. * Makefile.am (go_cmd_go_files): Add bug.go. (s-zdefaultcc): Write defaultPkgConfig. * Makefile.in: Rebuild. From-SVN: r244456
601 lines
17 KiB
Go
601 lines
17 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"context"
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"internal/nettrace"
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"time"
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)
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// A Dialer contains options for connecting to an address.
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//
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// The zero value for each field is equivalent to dialing
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// without that option. Dialing with the zero value of Dialer
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// is therefore equivalent to just calling the Dial function.
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type Dialer struct {
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// Timeout is the maximum amount of time a dial will wait for
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// a connect to complete. If Deadline is also set, it may fail
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// earlier.
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//
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// The default is no timeout.
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//
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// When dialing a name with multiple IP addresses, the timeout
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// may be divided between them.
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//
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// With or without a timeout, the operating system may impose
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// its own earlier timeout. For instance, TCP timeouts are
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// often around 3 minutes.
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Timeout time.Duration
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// Deadline is the absolute point in time after which dials
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// will fail. If Timeout is set, it may fail earlier.
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// Zero means no deadline, or dependent on the operating system
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// as with the Timeout option.
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Deadline time.Time
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// LocalAddr is the local address to use when dialing an
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// address. The address must be of a compatible type for the
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// network being dialed.
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// If nil, a local address is automatically chosen.
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LocalAddr Addr
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// DualStack enables RFC 6555-compliant "Happy Eyeballs" dialing
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// when the network is "tcp" and the destination is a host name
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// with both IPv4 and IPv6 addresses. This allows a client to
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// tolerate networks where one address family is silently broken.
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DualStack bool
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// FallbackDelay specifies the length of time to wait before
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// spawning a fallback connection, when DualStack is enabled.
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// If zero, a default delay of 300ms is used.
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FallbackDelay time.Duration
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// KeepAlive specifies the keep-alive period for an active
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// network connection.
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// If zero, keep-alives are not enabled. Network protocols
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// that do not support keep-alives ignore this field.
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KeepAlive time.Duration
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// Resolver optionally specifies an alternate resolver to use.
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Resolver *Resolver
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// Cancel is an optional channel whose closure indicates that
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// the dial should be canceled. Not all types of dials support
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// cancelation.
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//
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// Deprecated: Use DialContext instead.
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Cancel <-chan struct{}
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}
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func minNonzeroTime(a, b time.Time) time.Time {
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if a.IsZero() {
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return b
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}
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if b.IsZero() || a.Before(b) {
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return a
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}
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return b
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}
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// deadline returns the earliest of:
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// - now+Timeout
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// - d.Deadline
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// - the context's deadline
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// Or zero, if none of Timeout, Deadline, or context's deadline is set.
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func (d *Dialer) deadline(ctx context.Context, now time.Time) (earliest time.Time) {
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if d.Timeout != 0 { // including negative, for historical reasons
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earliest = now.Add(d.Timeout)
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}
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if d, ok := ctx.Deadline(); ok {
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earliest = minNonzeroTime(earliest, d)
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}
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return minNonzeroTime(earliest, d.Deadline)
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}
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func (d *Dialer) resolver() *Resolver {
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if d.Resolver != nil {
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return d.Resolver
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}
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return DefaultResolver
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}
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// partialDeadline returns the deadline to use for a single address,
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// when multiple addresses are pending.
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func partialDeadline(now, deadline time.Time, addrsRemaining int) (time.Time, error) {
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if deadline.IsZero() {
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return deadline, nil
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}
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timeRemaining := deadline.Sub(now)
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if timeRemaining <= 0 {
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return time.Time{}, errTimeout
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}
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// Tentatively allocate equal time to each remaining address.
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timeout := timeRemaining / time.Duration(addrsRemaining)
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// If the time per address is too short, steal from the end of the list.
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const saneMinimum = 2 * time.Second
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if timeout < saneMinimum {
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if timeRemaining < saneMinimum {
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timeout = timeRemaining
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} else {
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timeout = saneMinimum
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}
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}
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return now.Add(timeout), nil
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}
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func (d *Dialer) fallbackDelay() time.Duration {
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if d.FallbackDelay > 0 {
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return d.FallbackDelay
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} else {
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return 300 * time.Millisecond
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}
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}
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func parseNetwork(ctx context.Context, net string) (afnet string, proto int, err error) {
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i := last(net, ':')
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if i < 0 { // no colon
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switch net {
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case "tcp", "tcp4", "tcp6":
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case "udp", "udp4", "udp6":
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case "ip", "ip4", "ip6":
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case "unix", "unixgram", "unixpacket":
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default:
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return "", 0, UnknownNetworkError(net)
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}
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return net, 0, nil
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}
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afnet = net[:i]
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switch afnet {
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case "ip", "ip4", "ip6":
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protostr := net[i+1:]
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proto, i, ok := dtoi(protostr)
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if !ok || i != len(protostr) {
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proto, err = lookupProtocol(ctx, protostr)
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if err != nil {
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return "", 0, err
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}
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}
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return afnet, proto, nil
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}
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return "", 0, UnknownNetworkError(net)
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}
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// resolveAddrList resolves addr using hint and returns a list of
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// addresses. The result contains at least one address when error is
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// nil.
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func (r *Resolver) resolveAddrList(ctx context.Context, op, network, addr string, hint Addr) (addrList, error) {
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afnet, _, err := parseNetwork(ctx, network)
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if err != nil {
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return nil, err
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}
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if op == "dial" && addr == "" {
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return nil, errMissingAddress
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}
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switch afnet {
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case "unix", "unixgram", "unixpacket":
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addr, err := ResolveUnixAddr(afnet, addr)
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if err != nil {
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return nil, err
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}
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if op == "dial" && hint != nil && addr.Network() != hint.Network() {
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return nil, &AddrError{Err: "mismatched local address type", Addr: hint.String()}
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}
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return addrList{addr}, nil
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}
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addrs, err := r.internetAddrList(ctx, afnet, addr)
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if err != nil || op != "dial" || hint == nil {
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return addrs, err
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}
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var (
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tcp *TCPAddr
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udp *UDPAddr
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ip *IPAddr
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wildcard bool
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)
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switch hint := hint.(type) {
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case *TCPAddr:
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tcp = hint
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wildcard = tcp.isWildcard()
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case *UDPAddr:
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udp = hint
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wildcard = udp.isWildcard()
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case *IPAddr:
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ip = hint
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wildcard = ip.isWildcard()
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}
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naddrs := addrs[:0]
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for _, addr := range addrs {
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if addr.Network() != hint.Network() {
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return nil, &AddrError{Err: "mismatched local address type", Addr: hint.String()}
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}
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switch addr := addr.(type) {
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case *TCPAddr:
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if !wildcard && !addr.isWildcard() && !addr.IP.matchAddrFamily(tcp.IP) {
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continue
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}
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naddrs = append(naddrs, addr)
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case *UDPAddr:
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if !wildcard && !addr.isWildcard() && !addr.IP.matchAddrFamily(udp.IP) {
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continue
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}
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naddrs = append(naddrs, addr)
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case *IPAddr:
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if !wildcard && !addr.isWildcard() && !addr.IP.matchAddrFamily(ip.IP) {
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continue
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}
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naddrs = append(naddrs, addr)
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}
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}
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if len(naddrs) == 0 {
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return nil, &AddrError{Err: errNoSuitableAddress.Error(), Addr: hint.String()}
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}
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return naddrs, nil
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}
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// Dial connects to the address on the named network.
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//
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// Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only),
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// "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4"
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// (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and
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// "unixpacket".
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//
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// For TCP and UDP networks, addresses have the form host:port.
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// If host is a literal IPv6 address it must be enclosed
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// in square brackets as in "[::1]:80" or "[ipv6-host%zone]:80".
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// The functions JoinHostPort and SplitHostPort manipulate addresses
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// in this form.
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// If the host is empty, as in ":80", the local system is assumed.
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//
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// Examples:
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// Dial("tcp", "192.0.2.1:80")
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// Dial("tcp", "golang.org:http")
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// Dial("tcp", "[2001:db8::1]:http")
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// Dial("tcp", "[fe80::1%lo0]:80")
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// Dial("tcp", ":80")
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//
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// For IP networks, the network must be "ip", "ip4" or "ip6" followed
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// by a colon and a protocol number or name and the addr must be a
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// literal IP address.
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//
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// Examples:
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// Dial("ip4:1", "192.0.2.1")
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// Dial("ip6:ipv6-icmp", "2001:db8::1")
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//
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// For Unix networks, the address must be a file system path.
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//
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// If the host is resolved to multiple addresses,
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// Dial will try each address in order until one succeeds.
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func Dial(network, address string) (Conn, error) {
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var d Dialer
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return d.Dial(network, address)
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}
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// DialTimeout acts like Dial but takes a timeout.
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// The timeout includes name resolution, if required.
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func DialTimeout(network, address string, timeout time.Duration) (Conn, error) {
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d := Dialer{Timeout: timeout}
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return d.Dial(network, address)
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}
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// dialParam contains a Dial's parameters and configuration.
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type dialParam struct {
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Dialer
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network, address string
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}
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// Dial connects to the address on the named network.
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//
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// See func Dial for a description of the network and address
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// parameters.
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func (d *Dialer) Dial(network, address string) (Conn, error) {
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return d.DialContext(context.Background(), network, address)
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}
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// DialContext connects to the address on the named network using
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// the provided context.
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//
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// The provided Context must be non-nil. If the context expires before
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// the connection is complete, an error is returned. Once successfully
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// connected, any expiration of the context will not affect the
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// connection.
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//
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// When using TCP, and the host in the address parameter resolves to multiple
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// network addresses, any dial timeout (from d.Timeout or ctx) is spread
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// over each consecutive dial, such that each is given an appropriate
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// fraction of the time to connect.
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// For example, if a host has 4 IP addresses and the timeout is 1 minute,
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// the connect to each single address will be given 15 seconds to complete
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// before trying the next one.
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//
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// See func Dial for a description of the network and address
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// parameters.
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func (d *Dialer) DialContext(ctx context.Context, network, address string) (Conn, error) {
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if ctx == nil {
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panic("nil context")
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}
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deadline := d.deadline(ctx, time.Now())
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if !deadline.IsZero() {
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if d, ok := ctx.Deadline(); !ok || deadline.Before(d) {
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subCtx, cancel := context.WithDeadline(ctx, deadline)
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defer cancel()
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ctx = subCtx
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}
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}
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if oldCancel := d.Cancel; oldCancel != nil {
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subCtx, cancel := context.WithCancel(ctx)
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defer cancel()
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go func() {
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select {
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case <-oldCancel:
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cancel()
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case <-subCtx.Done():
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}
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}()
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ctx = subCtx
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}
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// Shadow the nettrace (if any) during resolve so Connect events don't fire for DNS lookups.
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resolveCtx := ctx
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if trace, _ := ctx.Value(nettrace.TraceKey{}).(*nettrace.Trace); trace != nil {
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shadow := *trace
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shadow.ConnectStart = nil
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shadow.ConnectDone = nil
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resolveCtx = context.WithValue(resolveCtx, nettrace.TraceKey{}, &shadow)
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}
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addrs, err := d.resolver().resolveAddrList(resolveCtx, "dial", network, address, d.LocalAddr)
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if err != nil {
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return nil, &OpError{Op: "dial", Net: network, Source: nil, Addr: nil, Err: err}
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}
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dp := &dialParam{
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Dialer: *d,
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network: network,
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address: address,
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}
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var primaries, fallbacks addrList
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if d.DualStack && network == "tcp" {
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primaries, fallbacks = addrs.partition(isIPv4)
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} else {
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primaries = addrs
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}
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var c Conn
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if len(fallbacks) > 0 {
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c, err = dialParallel(ctx, dp, primaries, fallbacks)
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} else {
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c, err = dialSerial(ctx, dp, primaries)
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}
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if err != nil {
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return nil, err
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}
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if tc, ok := c.(*TCPConn); ok && d.KeepAlive > 0 {
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setKeepAlive(tc.fd, true)
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setKeepAlivePeriod(tc.fd, d.KeepAlive)
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testHookSetKeepAlive()
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}
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return c, nil
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}
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// dialParallel races two copies of dialSerial, giving the first a
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// head start. It returns the first established connection and
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// closes the others. Otherwise it returns an error from the first
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// primary address.
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func dialParallel(ctx context.Context, dp *dialParam, primaries, fallbacks addrList) (Conn, error) {
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if len(fallbacks) == 0 {
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return dialSerial(ctx, dp, primaries)
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}
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returned := make(chan struct{})
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defer close(returned)
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type dialResult struct {
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Conn
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error
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primary bool
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done bool
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}
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results := make(chan dialResult) // unbuffered
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startRacer := func(ctx context.Context, primary bool) {
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ras := primaries
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if !primary {
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ras = fallbacks
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}
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c, err := dialSerial(ctx, dp, ras)
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select {
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case results <- dialResult{Conn: c, error: err, primary: primary, done: true}:
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case <-returned:
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if c != nil {
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c.Close()
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}
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}
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}
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var primary, fallback dialResult
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// Start the main racer.
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primaryCtx, primaryCancel := context.WithCancel(ctx)
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defer primaryCancel()
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go startRacer(primaryCtx, true)
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// Start the timer for the fallback racer.
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fallbackTimer := time.NewTimer(dp.fallbackDelay())
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defer fallbackTimer.Stop()
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for {
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select {
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case <-fallbackTimer.C:
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fallbackCtx, fallbackCancel := context.WithCancel(ctx)
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defer fallbackCancel()
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go startRacer(fallbackCtx, false)
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case res := <-results:
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if res.error == nil {
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return res.Conn, nil
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}
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if res.primary {
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primary = res
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} else {
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fallback = res
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}
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if primary.done && fallback.done {
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return nil, primary.error
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}
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if res.primary && fallbackTimer.Stop() {
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// If we were able to stop the timer, that means it
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// was running (hadn't yet started the fallback), but
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// we just got an error on the primary path, so start
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// the fallback immediately (in 0 nanoseconds).
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fallbackTimer.Reset(0)
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}
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}
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}
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}
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// dialSerial connects to a list of addresses in sequence, returning
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// either the first successful connection, or the first error.
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func dialSerial(ctx context.Context, dp *dialParam, ras addrList) (Conn, error) {
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var firstErr error // The error from the first address is most relevant.
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for i, ra := range ras {
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select {
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case <-ctx.Done():
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return nil, &OpError{Op: "dial", Net: dp.network, Source: dp.LocalAddr, Addr: ra, Err: mapErr(ctx.Err())}
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default:
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}
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deadline, _ := ctx.Deadline()
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partialDeadline, err := partialDeadline(time.Now(), deadline, len(ras)-i)
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if err != nil {
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// Ran out of time.
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if firstErr == nil {
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firstErr = &OpError{Op: "dial", Net: dp.network, Source: dp.LocalAddr, Addr: ra, Err: err}
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}
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break
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}
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dialCtx := ctx
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if partialDeadline.Before(deadline) {
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var cancel context.CancelFunc
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dialCtx, cancel = context.WithDeadline(ctx, partialDeadline)
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defer cancel()
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}
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c, err := dialSingle(dialCtx, dp, ra)
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if err == nil {
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return c, nil
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}
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if firstErr == nil {
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firstErr = err
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}
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}
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if firstErr == nil {
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firstErr = &OpError{Op: "dial", Net: dp.network, Source: nil, Addr: nil, Err: errMissingAddress}
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}
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return nil, firstErr
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}
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|
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// dialSingle attempts to establish and returns a single connection to
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// the destination address.
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func dialSingle(ctx context.Context, dp *dialParam, ra Addr) (c Conn, err error) {
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trace, _ := ctx.Value(nettrace.TraceKey{}).(*nettrace.Trace)
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if trace != nil {
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raStr := ra.String()
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if trace.ConnectStart != nil {
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trace.ConnectStart(dp.network, raStr)
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}
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if trace.ConnectDone != nil {
|
|
defer func() { trace.ConnectDone(dp.network, raStr, err) }()
|
|
}
|
|
}
|
|
la := dp.LocalAddr
|
|
switch ra := ra.(type) {
|
|
case *TCPAddr:
|
|
la, _ := la.(*TCPAddr)
|
|
c, err = dialTCP(ctx, dp.network, la, ra)
|
|
case *UDPAddr:
|
|
la, _ := la.(*UDPAddr)
|
|
c, err = dialUDP(ctx, dp.network, la, ra)
|
|
case *IPAddr:
|
|
la, _ := la.(*IPAddr)
|
|
c, err = dialIP(ctx, dp.network, la, ra)
|
|
case *UnixAddr:
|
|
la, _ := la.(*UnixAddr)
|
|
c, err = dialUnix(ctx, dp.network, la, ra)
|
|
default:
|
|
return nil, &OpError{Op: "dial", Net: dp.network, Source: la, Addr: ra, Err: &AddrError{Err: "unexpected address type", Addr: dp.address}}
|
|
}
|
|
if err != nil {
|
|
return nil, &OpError{Op: "dial", Net: dp.network, Source: la, Addr: ra, Err: err} // c is non-nil interface containing nil pointer
|
|
}
|
|
return c, nil
|
|
}
|
|
|
|
// Listen announces on the local network address laddr.
|
|
// The network net must be a stream-oriented network: "tcp", "tcp4",
|
|
// "tcp6", "unix" or "unixpacket".
|
|
// For TCP and UDP, the syntax of laddr is "host:port", like "127.0.0.1:8080".
|
|
// If host is omitted, as in ":8080", Listen listens on all available interfaces
|
|
// instead of just the interface with the given host address.
|
|
// See Dial for more details about address syntax.
|
|
//
|
|
// Listening on a hostname is not recommended because this creates a socket
|
|
// for at most one of its IP addresses.
|
|
func Listen(net, laddr string) (Listener, error) {
|
|
addrs, err := DefaultResolver.resolveAddrList(context.Background(), "listen", net, laddr, nil)
|
|
if err != nil {
|
|
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: nil, Err: err}
|
|
}
|
|
var l Listener
|
|
switch la := addrs.first(isIPv4).(type) {
|
|
case *TCPAddr:
|
|
l, err = ListenTCP(net, la)
|
|
case *UnixAddr:
|
|
l, err = ListenUnix(net, la)
|
|
default:
|
|
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: la, Err: &AddrError{Err: "unexpected address type", Addr: laddr}}
|
|
}
|
|
if err != nil {
|
|
return nil, err // l is non-nil interface containing nil pointer
|
|
}
|
|
return l, nil
|
|
}
|
|
|
|
// 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".
|
|
// For TCP and UDP, the syntax of laddr is "host:port", like "127.0.0.1:8080".
|
|
// If host is omitted, as in ":8080", ListenPacket listens on all available interfaces
|
|
// instead of just the interface with the given host address.
|
|
// See Dial for the syntax of laddr.
|
|
//
|
|
// Listening on a hostname is not recommended because this creates a socket
|
|
// for at most one of its IP addresses.
|
|
func ListenPacket(net, laddr string) (PacketConn, error) {
|
|
addrs, err := DefaultResolver.resolveAddrList(context.Background(), "listen", net, laddr, nil)
|
|
if err != nil {
|
|
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: nil, Err: err}
|
|
}
|
|
var l PacketConn
|
|
switch la := addrs.first(isIPv4).(type) {
|
|
case *UDPAddr:
|
|
l, err = ListenUDP(net, la)
|
|
case *IPAddr:
|
|
l, err = ListenIP(net, la)
|
|
case *UnixAddr:
|
|
l, err = ListenUnixgram(net, la)
|
|
default:
|
|
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: la, Err: &AddrError{Err: "unexpected address type", Addr: laddr}}
|
|
}
|
|
if err != nil {
|
|
return nil, err // l is non-nil interface containing nil pointer
|
|
}
|
|
return l, nil
|
|
}
|