upstream: add tests

upstream/upstream.go

@@ -11,6 +11,7 @@ import (
 	"net"
 	"net/netip"
 	"net/url"
+	"strconv"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -181,32 +182,51 @@ func AddressToUpstream(addr string, opts *Options) (u Upstream, err error) {
 		if err != nil {
 			return nil, fmt.Errorf("failed to parse %s: %w", addr, err)
 		}
+	} else {
+		uu = &url.URL{
+			Scheme: "udp",
+			Host:   addr,
+		}
+	}
 
-		// TODO(s.chzhen):  Validate hostname.  Consider DNS Stamp.
-		return urlToUpstream(uu, opts)
+	err = validateUpstreamURL(uu)
+	if err != nil {
+		// Don't wrap the error, because it's informative enough as is.
+		return nil, err
 	}
 
-	uu = &url.URL{
-		Scheme: "udp",
-		Host:   addr,
+	return urlToUpstream(uu, opts)
+}
+
+// validateUpstreamURL returns an error if the upstream URL is not valid.
+func validateUpstreamURL(u *url.URL) (err error) {
+	if u.Scheme == "sdns" {
+		return nil
 	}
 
-	_, err = netip.ParseAddr(addr)
-	if err == nil {
-		return urlToUpstream(uu, opts)
+	host := u.Host
+	h, port, splitErr := net.SplitHostPort(host)
+	if splitErr == nil {
+		// Validate port.
+		_, err = strconv.ParseUint(port, 10, 16)
+		if err != nil {
+			return fmt.Errorf("invalid port %s: %w", port, err)
+		}
+
+		host = h
 	}
 
-	_, err = netip.ParseAddrPort(addr)
+	_, err = netip.ParseAddr(host)
 	if err == nil {
-		return urlToUpstream(uu, opts)
+		return nil
 	}
 
-	err = netutil.ValidateHostname(addr)
+	err = netutil.ValidateHostname(host)
 	if err != nil {
-		return nil, fmt.Errorf("invalid address %s: %w", addr, err)
+		return fmt.Errorf("invalid address %s: %w", host, err)
 	}
 
-	return urlToUpstream(uu, opts)
+	return nil
 }
 
 // urlToUpstream converts uu to an Upstream using opts.

upstream/upstream_test.go

@@ -225,6 +225,14 @@ func TestAddressToUpstream(t *testing.T) {
 		addr: "1.1.1.1",
 		opt:  nil,
 		want: "1.1.1.1:53",
+	}, {
+		addr: "1.1.1.1:5353",
+		opt:  nil,
+		want: "1.1.1.1:5353",
+	}, {
+		addr: "one:5353",
+		opt:  nil,
+		want: "one:5353",
 	}, {
 		addr: "one.one.one.one",
 		opt:  nil,
@@ -271,17 +279,18 @@ func TestAddressToUpstream_bads(t *testing.T) {
 		wantErrMsg: "unsupported url scheme: asdf",
 	}, {
 		addr: "12345.1.1.1:1234567",
-		wantErrMsg: `invalid address 12345.1.1.1:1234567: bad hostname ` +
-			`"12345.1.1.1:1234567": bad top-level domain name label "1:1234567": ` +
-			`bad top-level domain name label rune ':'`,
+		wantErrMsg: `invalid port 1234567: strconv.ParseUint: parsing "1234567": ` +
+			`value out of range`,
 	}, {
 		addr: ":1234567",
-		wantErrMsg: `invalid address :1234567: bad hostname ":1234567": bad top-level ` +
-			`domain name label ":1234567": bad top-level domain name label rune ':'`,
+		wantErrMsg: `invalid port 1234567: strconv.ParseUint: parsing "1234567": ` +
+			`value out of range`,
 	}, {
-		addr: "host:",
-		wantErrMsg: `invalid address host:: bad hostname "host:": bad top-level ` +
-			`domain name label "host:": bad top-level domain name label rune ':'`,
+		addr:       "host:",
+		wantErrMsg: `invalid port : strconv.ParseUint: parsing "": invalid syntax`,
+	}, {
+		addr:       ":53",
+		wantErrMsg: `invalid address : bad hostname "": hostname is empty`,
 	}, {
 		addr: "!!!",
 		wantErrMsg: `invalid address !!!: bad hostname "!!!": bad top-level domain name ` +
@@ -290,6 +299,28 @@ func TestAddressToUpstream_bads(t *testing.T) {
 		addr: "123",
 		wantErrMsg: `invalid address 123: bad hostname "123": bad top-level domain name ` +
 			`label "123": all octets are numeric`,
+	}, {
+		addr: "tcp://12345.1.1.1:1234567",
+		wantErrMsg: `invalid port 1234567: strconv.ParseUint: parsing "1234567": ` +
+			`value out of range`,
+	}, {
+		addr: "tcp://:1234567",
+		wantErrMsg: `invalid port 1234567: strconv.ParseUint: parsing "1234567": ` +
+			`value out of range`,
+	}, {
+		addr:       "tcp://host:",
+		wantErrMsg: `invalid port : strconv.ParseUint: parsing "": invalid syntax`,
+	}, {
+		addr:       "tcp://:53",
+		wantErrMsg: `invalid address : bad hostname "": hostname is empty`,
+	}, {
+		addr: "tcp://!!!",
+		wantErrMsg: `invalid address !!!: bad hostname "!!!": bad top-level domain name ` +
+			`label "!!!": bad top-level domain name label rune '!'`,
+	}, {
+		addr: "tcp://123",
+		wantErrMsg: `invalid address 123: bad hostname "123": bad top-level domain name ` +
+			`label "123": all octets are numeric`,
 	}}
 
 	for _, tc := range testCases {