First implementation

vendor/golang.org/x/net/proxy/dial.go

@@ -0,0 +1,54 @@
+// Copyright 2019 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 proxy
+
+import (
+	"context"
+	"net"
+)
+
+// A ContextDialer dials using a context.
+type ContextDialer interface {
+	DialContext(ctx context.Context, network, address string) (net.Conn, error)
+}
+
+// Dial works like DialContext on net.Dialer but using a dialer returned by FromEnvironment.
+//
+// The passed ctx is only used for returning the Conn, not the lifetime of the Conn.
+//
+// Custom dialers (registered via RegisterDialerType) that do not implement ContextDialer
+// can leak a goroutine for as long as it takes the underlying Dialer implementation to timeout.
+//
+// A Conn returned from a successful Dial after the context has been cancelled will be immediately closed.
+func Dial(ctx context.Context, network, address string) (net.Conn, error) {
+	d := FromEnvironment()
+	if xd, ok := d.(ContextDialer); ok {
+		return xd.DialContext(ctx, network, address)
+	}
+	return dialContext(ctx, d, network, address)
+}
+
+// WARNING: this can leak a goroutine for as long as the underlying Dialer implementation takes to timeout
+// A Conn returned from a successful Dial after the context has been cancelled will be immediately closed.
+func dialContext(ctx context.Context, d Dialer, network, address string) (net.Conn, error) {
+	var (
+		conn net.Conn
+		done = make(chan struct{}, 1)
+		err  error
+	)
+	go func() {
+		conn, err = d.Dial(network, address)
+		close(done)
+		if conn != nil && ctx.Err() != nil {
+			conn.Close()
+		}
+	}()
+	select {
+	case <-ctx.Done():
+		err = ctx.Err()
+	case <-done:
+	}
+	return conn, err
+}

vendor/golang.org/x/net/proxy/direct.go

@@ -0,0 +1,31 @@
+// Copyright 2011 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 proxy
+
+import (
+	"context"
+	"net"
+)
+
+type direct struct{}
+
+// Direct implements Dialer by making network connections directly using net.Dial or net.DialContext.
+var Direct = direct{}
+
+var (
+	_ Dialer        = Direct
+	_ ContextDialer = Direct
+)
+
+// Dial directly invokes net.Dial with the supplied parameters.
+func (direct) Dial(network, addr string) (net.Conn, error) {
+	return net.Dial(network, addr)
+}
+
+// DialContext instantiates a net.Dialer and invokes its DialContext receiver with the supplied parameters.
+func (direct) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	var d net.Dialer
+	return d.DialContext(ctx, network, addr)
+}

vendor/golang.org/x/net/proxy/per_host.go

@@ -0,0 +1,155 @@
+// Copyright 2011 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 proxy
+
+import (
+	"context"
+	"net"
+	"strings"
+)
+
+// A PerHost directs connections to a default Dialer unless the host name
+// requested matches one of a number of exceptions.
+type PerHost struct {
+	def, bypass Dialer
+
+	bypassNetworks []*net.IPNet
+	bypassIPs      []net.IP
+	bypassZones    []string
+	bypassHosts    []string
+}
+
+// NewPerHost returns a PerHost Dialer that directs connections to either
+// defaultDialer or bypass, depending on whether the connection matches one of
+// the configured rules.
+func NewPerHost(defaultDialer, bypass Dialer) *PerHost {
+	return &PerHost{
+		def:    defaultDialer,
+		bypass: bypass,
+	}
+}
+
+// Dial connects to the address addr on the given network through either
+// defaultDialer or bypass.
+func (p *PerHost) Dial(network, addr string) (c net.Conn, err error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return p.dialerForRequest(host).Dial(network, addr)
+}
+
+// DialContext connects to the address addr on the given network through either
+// defaultDialer or bypass.
+func (p *PerHost) DialContext(ctx context.Context, network, addr string) (c net.Conn, err error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+	d := p.dialerForRequest(host)
+	if x, ok := d.(ContextDialer); ok {
+		return x.DialContext(ctx, network, addr)
+	}
+	return dialContext(ctx, d, network, addr)
+}
+
+func (p *PerHost) dialerForRequest(host string) Dialer {
+	if ip := net.ParseIP(host); ip != nil {
+		for _, net := range p.bypassNetworks {
+			if net.Contains(ip) {
+				return p.bypass
+			}
+		}
+		for _, bypassIP := range p.bypassIPs {
+			if bypassIP.Equal(ip) {
+				return p.bypass
+			}
+		}
+		return p.def
+	}
+
+	for _, zone := range p.bypassZones {
+		if strings.HasSuffix(host, zone) {
+			return p.bypass
+		}
+		if host == zone[1:] {
+			// For a zone ".example.com", we match "example.com"
+			// too.
+			return p.bypass
+		}
+	}
+	for _, bypassHost := range p.bypassHosts {
+		if bypassHost == host {
+			return p.bypass
+		}
+	}
+	return p.def
+}
+
+// AddFromString parses a string that contains comma-separated values
+// specifying hosts that should use the bypass proxy. Each value is either an
+// IP address, a CIDR range, a zone (*.example.com) or a host name
+// (localhost). A best effort is made to parse the string and errors are
+// ignored.
+func (p *PerHost) AddFromString(s string) {
+	hosts := strings.Split(s, ",")
+	for _, host := range hosts {
+		host = strings.TrimSpace(host)
+		if len(host) == 0 {
+			continue
+		}
+		if strings.Contains(host, "/") {
+			// We assume that it's a CIDR address like 127.0.0.0/8
+			if _, net, err := net.ParseCIDR(host); err == nil {
+				p.AddNetwork(net)
+			}
+			continue
+		}
+		if ip := net.ParseIP(host); ip != nil {
+			p.AddIP(ip)
+			continue
+		}
+		if strings.HasPrefix(host, "*.") {
+			p.AddZone(host[1:])
+			continue
+		}
+		p.AddHost(host)
+	}
+}
+
+// AddIP specifies an IP address that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match an IP.
+func (p *PerHost) AddIP(ip net.IP) {
+	p.bypassIPs = append(p.bypassIPs, ip)
+}
+
+// AddNetwork specifies an IP range that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match.
+func (p *PerHost) AddNetwork(net *net.IPNet) {
+	p.bypassNetworks = append(p.bypassNetworks, net)
+}
+
+// AddZone specifies a DNS suffix that will use the bypass proxy. A zone of
+// "example.com" matches "example.com" and all of its subdomains.
+func (p *PerHost) AddZone(zone string) {
+	if strings.HasSuffix(zone, ".") {
+		zone = zone[:len(zone)-1]
+	}
+	if !strings.HasPrefix(zone, ".") {
+		zone = "." + zone
+	}
+	p.bypassZones = append(p.bypassZones, zone)
+}
+
+// AddHost specifies a host name that will use the bypass proxy.
+func (p *PerHost) AddHost(host string) {
+	if strings.HasSuffix(host, ".") {
+		host = host[:len(host)-1]
+	}
+	p.bypassHosts = append(p.bypassHosts, host)
+}

vendor/golang.org/x/net/proxy/proxy.go

@@ -0,0 +1,149 @@
+// Copyright 2011 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 proxy provides support for a variety of protocols to proxy network
+// data.
+package proxy // import "golang.org/x/net/proxy"
+
+import (
+	"errors"
+	"net"
+	"net/url"
+	"os"
+	"sync"
+)
+
+// A Dialer is a means to establish a connection.
+// Custom dialers should also implement ContextDialer.
+type Dialer interface {
+	// Dial connects to the given address via the proxy.
+	Dial(network, addr string) (c net.Conn, err error)
+}
+
+// Auth contains authentication parameters that specific Dialers may require.
+type Auth struct {
+	User, Password string
+}
+
+// FromEnvironment returns the dialer specified by the proxy-related
+// variables in the environment and makes underlying connections
+// directly.
+func FromEnvironment() Dialer {
+	return FromEnvironmentUsing(Direct)
+}
+
+// FromEnvironmentUsing returns the dialer specify by the proxy-related
+// variables in the environment and makes underlying connections
+// using the provided forwarding Dialer (for instance, a *net.Dialer
+// with desired configuration).
+func FromEnvironmentUsing(forward Dialer) Dialer {
+	allProxy := allProxyEnv.Get()
+	if len(allProxy) == 0 {
+		return forward
+	}
+
+	proxyURL, err := url.Parse(allProxy)
+	if err != nil {
+		return forward
+	}
+	proxy, err := FromURL(proxyURL, forward)
+	if err != nil {
+		return forward
+	}
+
+	noProxy := noProxyEnv.Get()
+	if len(noProxy) == 0 {
+		return proxy
+	}
+
+	perHost := NewPerHost(proxy, forward)
+	perHost.AddFromString(noProxy)
+	return perHost
+}
+
+// proxySchemes is a map from URL schemes to a function that creates a Dialer
+// from a URL with such a scheme.
+var proxySchemes map[string]func(*url.URL, Dialer) (Dialer, error)
+
+// RegisterDialerType takes a URL scheme and a function to generate Dialers from
+// a URL with that scheme and a forwarding Dialer. Registered schemes are used
+// by FromURL.
+func RegisterDialerType(scheme string, f func(*url.URL, Dialer) (Dialer, error)) {
+	if proxySchemes == nil {
+		proxySchemes = make(map[string]func(*url.URL, Dialer) (Dialer, error))
+	}
+	proxySchemes[scheme] = f
+}
+
+// FromURL returns a Dialer given a URL specification and an underlying
+// Dialer for it to make network requests.
+func FromURL(u *url.URL, forward Dialer) (Dialer, error) {
+	var auth *Auth
+	if u.User != nil {
+		auth = new(Auth)
+		auth.User = u.User.Username()
+		if p, ok := u.User.Password(); ok {
+			auth.Password = p
+		}
+	}
+
+	switch u.Scheme {
+	case "socks5", "socks5h":
+		addr := u.Hostname()
+		port := u.Port()
+		if port == "" {
+			port = "1080"
+		}
+		return SOCKS5("tcp", net.JoinHostPort(addr, port), auth, forward)
+	}
+
+	// If the scheme doesn't match any of the built-in schemes, see if it
+	// was registered by another package.
+	if proxySchemes != nil {
+		if f, ok := proxySchemes[u.Scheme]; ok {
+			return f(u, forward)
+		}
+	}
+
+	return nil, errors.New("proxy: unknown scheme: " + u.Scheme)
+}
+
+var (
+	allProxyEnv = &envOnce{
+		names: []string{"ALL_PROXY", "all_proxy"},
+	}
+	noProxyEnv = &envOnce{
+		names: []string{"NO_PROXY", "no_proxy"},
+	}
+)
+
+// envOnce looks up an environment variable (optionally by multiple
+// names) once. It mitigates expensive lookups on some platforms
+// (e.g. Windows).
+// (Borrowed from net/http/transport.go)
+type envOnce struct {
+	names []string
+	once  sync.Once
+	val   string
+}
+
+func (e *envOnce) Get() string {
+	e.once.Do(e.init)
+	return e.val
+}
+
+func (e *envOnce) init() {
+	for _, n := range e.names {
+		e.val = os.Getenv(n)
+		if e.val != "" {
+			return
+		}
+	}
+}
+
+// reset is used by tests
+func (e *envOnce) reset() {
+	e.once = sync.Once{}
+	e.val = ""
+}

vendor/golang.org/x/net/proxy/socks5.go

@@ -0,0 +1,42 @@
+// Copyright 2011 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 proxy
+
+import (
+	"context"
+	"net"
+
+	"golang.org/x/net/internal/socks"
+)
+
+// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given
+// address with an optional username and password.
+// See RFC 1928 and RFC 1929.
+func SOCKS5(network, address string, auth *Auth, forward Dialer) (Dialer, error) {
+	d := socks.NewDialer(network, address)
+	if forward != nil {
+		if f, ok := forward.(ContextDialer); ok {
+			d.ProxyDial = func(ctx context.Context, network string, address string) (net.Conn, error) {
+				return f.DialContext(ctx, network, address)
+			}
+		} else {
+			d.ProxyDial = func(ctx context.Context, network string, address string) (net.Conn, error) {
+				return dialContext(ctx, forward, network, address)
+			}
+		}
+	}
+	if auth != nil {
+		up := socks.UsernamePassword{
+			Username: auth.User,
+			Password: auth.Password,
+		}
+		d.AuthMethods = []socks.AuthMethod{
+			socks.AuthMethodNotRequired,
+			socks.AuthMethodUsernamePassword,
+		}
+		d.Authenticate = up.Authenticate
+	}
+	return d, nil
+}