proxy dialer

go.mod

@@ -3,7 +3,8 @@ module github.com/Snawoot/dumbproxy
 go 1.13
 
 require (
-	github.com/tg123/go-htpasswd v1.2.0 // indirect
+	github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b // indirect
+	github.com/tg123/go-htpasswd v1.2.0
 	golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90
-	golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b // indirect
+	golang.org/x/net v0.5.0 // indirect
 )

go.sum

@@ -1,29 +1,54 @@
 github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962 h1:KeNholpO2xKjgaaSyd+DyQRrsQjhbSeS7qe4nEw8aQw=
 github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962/go.mod h1:kC29dT1vFpj7py2OvG1khBdQpo3kInWP+6QipLbdngo=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b h1:xZ59n7Frzh8CwyfAapUZLSg+gXH5m63YEaFCMpDHhpI=
+github.com/magisterquis/connectproxy v0.0.0-20200725203833-3582e84f0c9b/go.mod h1:uDd4sYVYsqcxAB8j+Q7uhL6IJCs/r1kxib1HV4bgOMg=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/tg123/go-htpasswd v1.2.0 h1:UKp34m9H467/xklxUxU15wKRru7fwXoTojtxg25ITF0=
 github.com/tg123/go-htpasswd v1.2.0/go.mod h1:h7IzlfpvIWnVJhNZ0nQ9HaFxHb7pn5uFJYLlEUJa2sM=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20190228161510-8dd112bcdc25/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90 h1:Y/gsMcFOcR+6S6f3YeMKl5g+dZMEWqcz5Czj/GWYbkM=
 golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b h1:ZmngSVLe/wycRns9MKikG9OWIEjGcGAkacif7oYQaUY=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
-golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
+golang.org/x/net v0.5.0 h1:GyT4nK/YDHSqa1c4753ouYCDajOYKTja9Xb/OHtgvSw=
+golang.org/x/net v0.5.0/go.mod h1:DivGGAXEgPSlEBzxGzZI+ZLohi+xUj054jfeKui00ws=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 h1:WIoqL4EROvwiPdUtaip4VcDdpZ4kha7wBWZrbVKCIZg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18=
+golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.4.0 h1:O7UWfv5+A2qiuulQk30kVinPoMtoIPeVaKLEgLpVkvg=
+golang.org/x/term v0.4.0/go.mod h1:9P2UbLfCdcvo3p/nzKvsmas4TnlujnuoV9hGgYzW1lQ=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.6.0 h1:3XmdazWV+ubf7QgHSTWeykHOci5oeekaGJBLkrkaw4k=
+golang.org/x/text v0.6.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -70,6 +70,7 @@ type CLIArgs struct {
 	passwd            string
 	passwdCost        int
 	positionalArgs    []string
+	proxy             []string
 }
 
 func parse_args() CLIArgs {
@@ -95,6 +96,10 @@ func parse_args() CLIArgs {
 	flag.StringVar(&args.passwd, "passwd", "", "update given htpasswd file and add/set password for username. "+
 		"Username and password can be passed as positional arguments or requested interactively")
 	flag.IntVar(&args.passwdCost, "passwd-cost", bcrypt.MinCost, "bcrypt password cost (for -passwd mode)")
+	flag.Func("proxy", "upstream proxy URL. Can be repeated multiple times to chain proxies", func(p string) error {
+		args.proxy = append(args.proxy, p)
+		return nil
+	})
 	flag.Parse()
 	args.positionalArgs = flag.Args()
 	return args
@@ -140,9 +145,19 @@ func run() int {
 	}
 	defer auth.Stop()
 
+	var dialer Dialer = new(net.Dialer)
+	for _, proxyURL := range args.proxy {
+		newDialer, err := proxyDialerFromURL(proxyURL, dialer)
+		if err != nil {
+			mainLogger.Critical("Failed to create dialer for proxy %q: %v", proxyURL, err)
+			return 3
+		}
+		dialer = newDialer
+	}
+
 	server := http.Server{
 		Addr:              args.bind_address,
-		Handler:           NewProxyHandler(args.timeout, auth, new(net.Dialer), proxyLogger),
+		Handler:           NewProxyHandler(args.timeout, auth, maybeWrapWithContextDialer(dialer), proxyLogger),
 		ErrorLog:          log.New(logWriter, "HTTPSRV : ", log.LstdFlags|log.Lshortfile),
 		ReadTimeout:       0,
 		ReadHeaderTimeout: 0,
@@ -187,7 +202,9 @@ func run() int {
 		}
 		server.TLSConfig = cfg
 		err = server.ListenAndServeTLS("", "")
+		mainLogger.Info("Proxy server started.")
 	} else {
+		mainLogger.Info("Proxy server started.")
 		err = server.ListenAndServe()
 	}
 	mainLogger.Critical("Server terminated with a reason: %v", err)

utils.go

@@ -12,13 +12,16 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/magisterquis/connectproxy"
 	"golang.org/x/crypto/bcrypt"
 	"golang.org/x/crypto/ssh/terminal"
+	xproxy "golang.org/x/net/proxy"
 )
 
 const COPY_BUF = 128 * 1024
@@ -300,3 +303,60 @@ func prompt(prompt string, secure bool) (string, error) {
 	}
 	return input, nil
 }
+
+type Dialer xproxy.Dialer
+type ContextDialer xproxy.ContextDialer
+
+var registerDialerTypesOnce sync.Once
+
+func proxyDialerFromURL(proxyURL string, forward Dialer) (Dialer, error) {
+	registerDialerTypesOnce.Do(func() {
+		xproxy.RegisterDialerType("http", connectproxy.New)
+		xproxy.RegisterDialerType("https", connectproxy.New)
+	})
+	parsedURL, err := url.Parse(proxyURL)
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse proxy URL: %w", err)
+	}
+	d, err := xproxy.FromURL(parsedURL, forward)
+	if err != nil {
+		return nil, fmt.Errorf("unable to construct proxy dialer from URL %q: %w", proxyURL, err)
+	}
+	return d, nil
+}
+
+type wrappedDialer struct {
+	d Dialer
+}
+
+func (wd wrappedDialer) Dial(net, address string) (net.Conn, error) {
+	return wd.d.Dial(net, address)
+}
+
+func (wd wrappedDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	var (
+		conn net.Conn
+		done = make(chan struct{}, 1)
+		err  error
+	)
+	go func() {
+		conn, err = wd.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
+}
+
+func maybeWrapWithContextDialer(d Dialer) ContextDialer {
+	if xd, ok := d.(ContextDialer); ok {
+		return xd
+	}
+	return wrappedDialer{d}
+}