Merge pull request #2008 from miminar/honor-x-forwarded-port

Honor X-Forwarded-Port header
This commit is contained in:
Derek McGowan 2016-11-02 12:56:17 -07:00 committed by GitHub
commit fbe6e8d212
4 changed files with 698 additions and 24 deletions

View file

@ -0,0 +1,161 @@
package v2
import (
"fmt"
"regexp"
"strings"
"unicode"
)
var (
// according to rfc7230
reToken = regexp.MustCompile(`^[^"(),/:;<=>?@[\]{}[:space:][:cntrl:]]+`)
reQuotedValue = regexp.MustCompile(`^[^\\"]+`)
reEscapedCharacter = regexp.MustCompile(`^[[:blank:][:graph:]]`)
)
// parseForwardedHeader is a benevolent parser of Forwarded header defined in rfc7239. The header contains
// a comma-separated list of forwarding key-value pairs. Each list element is set by single proxy. The
// function parses only the first element of the list, which is set by the very first proxy. It returns a map
// of corresponding key-value pairs and an unparsed slice of the input string.
//
// Examples of Forwarded header values:
//
// 1. Forwarded: For=192.0.2.43; Proto=https,For="[2001:db8:cafe::17]",For=unknown
// 2. Forwarded: for="192.0.2.43:443"; host="registry.example.org", for="10.10.05.40:80"
//
// The first will be parsed into {"for": "192.0.2.43", "proto": "https"} while the second into
// {"for": "192.0.2.43:443", "host": "registry.example.org"}.
func parseForwardedHeader(forwarded string) (map[string]string, string, error) {
// Following are states of forwarded header parser. Any state could transition to a failure.
const (
// terminating state; can transition to Parameter
stateElement = iota
// terminating state; can transition to KeyValueDelimiter
stateParameter
// can transition to Value
stateKeyValueDelimiter
// can transition to one of { QuotedValue, PairEnd }
stateValue
// can transition to one of { EscapedCharacter, PairEnd }
stateQuotedValue
// can transition to one of { QuotedValue }
stateEscapedCharacter
// terminating state; can transition to one of { Parameter, Element }
statePairEnd
)
var (
parameter string
value string
parse = forwarded[:]
res = map[string]string{}
state = stateElement
)
Loop:
for {
// skip spaces unless in quoted value
if state != stateQuotedValue && state != stateEscapedCharacter {
parse = strings.TrimLeftFunc(parse, unicode.IsSpace)
}
if len(parse) == 0 {
if state != stateElement && state != statePairEnd && state != stateParameter {
return nil, parse, fmt.Errorf("unexpected end of input")
}
// terminating
break
}
switch state {
// terminate at list element delimiter
case stateElement:
if parse[0] == ',' {
parse = parse[1:]
break Loop
}
state = stateParameter
// parse parameter (the key of key-value pair)
case stateParameter:
match := reToken.FindString(parse)
if len(match) == 0 {
return nil, parse, fmt.Errorf("failed to parse token at position %d", len(forwarded)-len(parse))
}
parameter = strings.ToLower(match)
parse = parse[len(match):]
state = stateKeyValueDelimiter
// parse '='
case stateKeyValueDelimiter:
if parse[0] != '=' {
return nil, parse, fmt.Errorf("expected '=', not '%c' at position %d", parse[0], len(forwarded)-len(parse))
}
parse = parse[1:]
state = stateValue
// parse value or quoted value
case stateValue:
if parse[0] == '"' {
parse = parse[1:]
state = stateQuotedValue
} else {
value = reToken.FindString(parse)
if len(value) == 0 {
return nil, parse, fmt.Errorf("failed to parse value at position %d", len(forwarded)-len(parse))
}
if _, exists := res[parameter]; exists {
return nil, parse, fmt.Errorf("duplicate parameter %q at position %d", parameter, len(forwarded)-len(parse))
}
res[parameter] = value
parse = parse[len(value):]
value = ""
state = statePairEnd
}
// parse a part of quoted value until the first backslash
case stateQuotedValue:
match := reQuotedValue.FindString(parse)
value += match
parse = parse[len(match):]
switch {
case len(parse) == 0:
return nil, parse, fmt.Errorf("unterminated quoted string")
case parse[0] == '"':
res[parameter] = value
value = ""
parse = parse[1:]
state = statePairEnd
case parse[0] == '\\':
parse = parse[1:]
state = stateEscapedCharacter
}
// parse escaped character in a quoted string, ignore the backslash
// transition back to QuotedValue state
case stateEscapedCharacter:
c := reEscapedCharacter.FindString(parse)
if len(c) == 0 {
return nil, parse, fmt.Errorf("invalid escape sequence at position %d", len(forwarded)-len(parse)-1)
}
value += c
parse = parse[1:]
state = stateQuotedValue
// expect either a new key-value pair, new list or end of input
case statePairEnd:
switch parse[0] {
case ';':
parse = parse[1:]
state = stateParameter
case ',':
state = stateElement
default:
return nil, parse, fmt.Errorf("expected ',' or ';', not %c at position %d", parse[0], len(forwarded)-len(parse))
}
}
}
return res, parse, nil
}

View file

@ -0,0 +1,161 @@
package v2
import (
"testing"
)
func TestParseForwardedHeader(t *testing.T) {
for _, tc := range []struct {
name string
raw string
expected map[string]string
expectedRest string
expectedError bool
}{
{
name: "empty",
raw: "",
},
{
name: "one pair",
raw: " key = value ",
expected: map[string]string{"key": "value"},
},
{
name: "two pairs",
raw: " key1 = value1; key2=value2",
expected: map[string]string{"key1": "value1", "key2": "value2"},
},
{
name: "uppercase parameter",
raw: "KeY=VaL",
expected: map[string]string{"key": "VaL"},
},
{
name: "missing key=value pair - be tolerant",
raw: "key=val;",
expected: map[string]string{"key": "val"},
},
{
name: "quoted values",
raw: `key="val";param = "[[ $((1 + 1)) == 3 ]] && echo panic!;" ; p=" abcd "`,
expected: map[string]string{"key": "val", "param": "[[ $((1 + 1)) == 3 ]] && echo panic!;", "p": " abcd "},
},
{
name: "empty quoted value",
raw: `key=""`,
expected: map[string]string{"key": ""},
},
{
name: "quoted double quotes",
raw: `key="\"value\""`,
expected: map[string]string{"key": `"value"`},
},
{
name: "quoted backslash",
raw: `key="\"\\\""`,
expected: map[string]string{"key": `"\"`},
},
{
name: "ignore subsequent elements",
raw: "key=a, param= b",
expected: map[string]string{"key": "a"},
expectedRest: " param= b",
},
{
name: "empty element - be tolerant",
raw: " , key=val",
expectedRest: " key=val",
},
{
name: "obscure key",
raw: `ob₷C&r€ = value`,
expected: map[string]string{`ob₷c&r€`: "value"},
},
{
name: "duplicate parameter",
raw: "key=a; p=b; key=c",
expectedError: true,
},
{
name: "empty parameter",
raw: "=value",
expectedError: true,
},
{
name: "empty value",
raw: "key= ",
expectedError: true,
},
{
name: "empty value before a new element ",
raw: "key=,",
expectedError: true,
},
{
name: "empty value before a new pair",
raw: "key=;",
expectedError: true,
},
{
name: "just parameter",
raw: "key",
expectedError: true,
},
{
name: "missing key-value",
raw: "a=b;;",
expectedError: true,
},
{
name: "unclosed quoted value",
raw: `key="value`,
expectedError: true,
},
{
name: "escaped terminating dquote",
raw: `key="value\"`,
expectedError: true,
},
{
name: "just a quoted value",
raw: `"key=val"`,
expectedError: true,
},
{
name: "quoted key",
raw: `"key"=val`,
expectedError: true,
},
} {
parsed, rest, err := parseForwardedHeader(tc.raw)
if err != nil && !tc.expectedError {
t.Errorf("[%s] got unexpected error: %v", tc.name, err)
}
if err == nil && tc.expectedError {
t.Errorf("[%s] got unexpected non-error", tc.name)
}
if err != nil || tc.expectedError {
continue
}
for key, value := range tc.expected {
v, exists := parsed[key]
if !exists {
t.Errorf("[%s] missing expected parameter %q", tc.name, key)
continue
}
if v != value {
t.Errorf("[%s] got unexpected value for parameter %q: %q != %q", tc.name, key, v, value)
}
}
for key, value := range parsed {
if _, exists := tc.expected[key]; !exists {
t.Errorf("[%s] got unexpected key/value pair: %q=%q", tc.name, key, value)
}
}
if rest != tc.expectedRest {
t.Errorf("[%s] got unexpected unparsed string: %q != %q", tc.name, rest, tc.expectedRest)
}
}
}

View file

@ -1,8 +1,10 @@
package v2
import (
"net"
"net/http"
"net/url"
"strconv"
"strings"
"github.com/docker/distribution/reference"
@ -49,10 +51,14 @@ func NewURLBuilderFromRequest(r *http.Request, relative bool) *URLBuilder {
var scheme string
forwardedProto := r.Header.Get("X-Forwarded-Proto")
// TODO: log the error
forwardedHeader, _, _ := parseForwardedHeader(r.Header.Get("Forwarded"))
switch {
case len(forwardedProto) > 0:
scheme = forwardedProto
case len(forwardedHeader["proto"]) > 0:
scheme = forwardedHeader["proto"]
case r.TLS != nil:
scheme = "https"
case len(r.URL.Scheme) > 0:
@ -62,14 +68,46 @@ func NewURLBuilderFromRequest(r *http.Request, relative bool) *URLBuilder {
}
host := r.Host
forwardedHost := r.Header.Get("X-Forwarded-Host")
if len(forwardedHost) > 0 {
if forwardedHost := r.Header.Get("X-Forwarded-Host"); len(forwardedHost) > 0 {
// According to the Apache mod_proxy docs, X-Forwarded-Host can be a
// comma-separated list of hosts, to which each proxy appends the
// requested host. We want to grab the first from this comma-separated
// list.
hosts := strings.SplitN(forwardedHost, ",", 2)
host = strings.TrimSpace(hosts[0])
} else if addr, exists := forwardedHeader["for"]; exists {
host = addr
} else if h, exists := forwardedHeader["host"]; exists {
host = h
}
portLessHost, port := host, ""
if !isIPv6Address(portLessHost) {
// with go 1.6, this would treat the last part of IPv6 address as a port
portLessHost, port, _ = net.SplitHostPort(host)
}
if forwardedPort := r.Header.Get("X-Forwarded-Port"); len(port) == 0 && len(forwardedPort) > 0 {
ports := strings.SplitN(forwardedPort, ",", 2)
forwardedPort = strings.TrimSpace(ports[0])
if _, err := strconv.ParseInt(forwardedPort, 10, 32); err == nil {
port = forwardedPort
}
}
if len(portLessHost) > 0 {
host = portLessHost
}
if len(port) > 0 {
// remove enclosing brackets of ipv6 address otherwise they will be duplicated
if len(host) > 1 && host[0] == '[' && host[len(host)-1] == ']' {
host = host[1 : len(host)-1]
}
// JoinHostPort properly encloses ipv6 addresses in square brackets
host = net.JoinHostPort(host, port)
} else if isIPv6Address(host) && host[0] != '[' {
// ipv6 needs to be enclosed in square brackets in urls
host = "[" + host + "]"
}
basePath := routeDescriptorsMap[RouteNameBase].Path
@ -249,3 +287,28 @@ func appendValues(u string, values ...url.Values) string {
return appendValuesURL(up, values...).String()
}
// isIPv6Address returns true if given string is a valid IPv6 address. No port is allowed. The address may be
// enclosed in square brackets.
func isIPv6Address(host string) bool {
if len(host) > 1 && host[0] == '[' && host[len(host)-1] == ']' {
host = host[1 : len(host)-1]
}
// The IPv6 scoped addressing zone identifier starts after the last percent sign.
if i := strings.LastIndexByte(host, '%'); i > 0 {
host = host[:i]
}
ip := net.ParseIP(host)
if ip == nil {
return false
}
if ip.To16() == nil {
return false
}
if ip.To4() == nil {
return true
}
// dot can be present in ipv4-mapped address, it needs to come after a colon though
i := strings.IndexAny(host, ":.")
return i >= 0 && host[i] == ':'
}

View file

@ -165,50 +165,222 @@ func TestBuilderFromRequest(t *testing.T) {
t.Fatal(err)
}
forwardedProtoHeader := make(http.Header, 1)
forwardedProtoHeader.Set("X-Forwarded-Proto", "https")
forwardedHostHeader1 := make(http.Header, 1)
forwardedHostHeader1.Set("X-Forwarded-Host", "first.example.com")
forwardedHostHeader2 := make(http.Header, 1)
forwardedHostHeader2.Set("X-Forwarded-Host", "first.example.com, proxy1.example.com")
testRequests := []struct {
name string
request *http.Request
base string
configHost url.URL
}{
{
name: "no forwarded header",
request: &http.Request{URL: u, Host: u.Host},
base: "http://example.com",
},
{
request: &http.Request{URL: u, Host: u.Host, Header: forwardedProtoHeader},
base: "http://example.com",
name: "https protocol forwarded with a non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Proto": []string{"https"},
}},
base: "http://example.com",
},
{
request: &http.Request{URL: u, Host: u.Host, Header: forwardedProtoHeader},
base: "https://example.com",
name: "forwarded protocol is the same",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Proto": []string{"https"},
}},
base: "https://example.com",
},
{
request: &http.Request{URL: u, Host: u.Host, Header: forwardedHostHeader1},
base: "http://first.example.com",
name: "forwarded host with a non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com"},
}},
base: "http://first.example.com",
},
{
request: &http.Request{URL: u, Host: u.Host, Header: forwardedHostHeader2},
base: "http://first.example.com",
name: "forwarded multiple hosts a with non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com, proxy1.example.com"},
}},
base: "http://first.example.com",
},
{
request: &http.Request{URL: u, Host: u.Host, Header: forwardedHostHeader2},
base: "https://third.example.com:5000",
name: "host configured in config file takes priority",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com, proxy1.example.com"},
}},
base: "https://third.example.com:5000",
configHost: url.URL{
Scheme: "https",
Host: "third.example.com:5000",
},
},
{
name: "forwarded host and port with just one non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com:443"},
}},
base: "http://first.example.com:443",
},
{
name: "forwarded port with a non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Port": []string{"5000"},
}},
base: "http://example.com:5000",
},
{
name: "forwarded multiple ports with a non-standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Port": []string{"443 , 5001"},
}},
base: "http://example.com:443",
},
{
name: "several non-standard headers",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Proto": []string{"https"},
"X-Forwarded-Host": []string{" first.example.com "},
"X-Forwarded-Port": []string{" 12345 \t"},
}},
base: "http://first.example.com:12345",
},
{
name: "forwarded host with port supplied takes priority",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com:5000"},
"X-Forwarded-Port": []string{"80"},
}},
base: "http://first.example.com:5000",
},
{
name: "malformed forwarded port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Host": []string{"first.example.com"},
"X-Forwarded-Port": []string{"abcd"},
}},
base: "http://first.example.com",
},
{
name: "forwarded protocol and addr using standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`proto=https;for="192.168.22.30:80"`},
}},
base: "https://192.168.22.30:80",
},
{
name: "forwarded addr takes priority over host",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`host=reg.example.com;for="192.168.22.30:5000"`},
}},
base: "http://192.168.22.30:5000",
},
{
name: "forwarded host and protocol using standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`host=reg.example.com;proto=https`},
}},
base: "https://reg.example.com",
},
{
name: "process just the first standard forwarded header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`host="reg.example.com:88";proto=http`, `host=reg.example.com;proto=https`},
}},
base: "http://reg.example.com:88",
},
{
name: "process just the first list element of standard header",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="reg.example.com:443";proto=https, for="reg.example.com:80";proto=http`},
}},
base: "https://reg.example.com:443",
},
{
name: "IPv6 address override port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="2607:f0d0:1002:51::4"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[2607:f0d0:1002:51::4]:5001",
},
{
name: "IPv6 address with port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="[2607:f0d0:1002:51::4]:4000"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[2607:f0d0:1002:51::4]:4000",
},
{
name: "IPv6 long address override port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="2607:f0d0:1002:0051:0000:0000:0000:0004"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[2607:f0d0:1002:0051:0000:0000:0000:0004]:5001",
},
{
name: "IPv6 long address enclosed in brackets - be benevolent",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="[2607:f0d0:1002:0051:0000:0000:0000:0004]"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[2607:f0d0:1002:0051:0000:0000:0000:0004]:5001",
},
{
name: "IPv6 long address with port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="[2607:f0d0:1002:0051:0000:0000:0000:0004]:4321"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[2607:f0d0:1002:0051:0000:0000:0000:0004]:4321",
},
{
name: "IPv6 address with zone ID",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="fe80::bd0f:a8bc:6480:238b%11"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[fe80::bd0f:a8bc:6480:238b%2511]:5001",
},
{
name: "IPv6 address with zone ID and port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="[fe80::bd0f:a8bc:6480:238b%eth0]:12345"`},
"X-Forwarded-Port": []string{"5001"},
}},
base: "http://[fe80::bd0f:a8bc:6480:238b%25eth0]:12345",
},
{
name: "IPv6 address without port",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"Forwarded": []string{`for="::FFFF:129.144.52.38"`},
}},
base: "http://[::FFFF:129.144.52.38]",
},
{
name: "non-standard and standard forward headers",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Proto": []string{`https`},
"X-Forwarded-Host": []string{`first.example.com`},
"X-Forwarded-Port": []string{``},
"Forwarded": []string{`host=first.example.com; proto=https`},
}},
base: "https://first.example.com",
},
{
name: "non-standard headers take precedence over standard one",
request: &http.Request{URL: u, Host: u.Host, Header: http.Header{
"X-Forwarded-Proto": []string{`http`},
"Forwarded": []string{`host=second.example.com; proto=https`},
"X-Forwarded-Host": []string{`first.example.com`},
"X-Forwarded-Port": []string{`4000`},
}},
base: "http://first.example.com:4000",
},
}
doTest := func(relative bool) {
for _, tr := range testRequests {
var builder *URLBuilder
@ -221,7 +393,7 @@ func TestBuilderFromRequest(t *testing.T) {
for _, testCase := range makeURLBuilderTestCases(builder) {
buildURL, err := testCase.build()
if err != nil {
t.Fatalf("%s: error building url: %v", testCase.description, err)
t.Fatalf("[relative=%t, request=%q, case=%q]: error building url: %v", relative, tr.name, testCase.description, err)
}
var expectedURL string
@ -244,11 +416,12 @@ func TestBuilderFromRequest(t *testing.T) {
}
if buildURL != expectedURL {
t.Fatalf("%s: %q != %q", testCase.description, buildURL, expectedURL)
t.Errorf("[relative=%t, request=%q, case=%q]: %q != %q", relative, tr.name, testCase.description, buildURL, expectedURL)
}
}
}
}
doTest(true)
doTest(false)
}
@ -332,3 +505,119 @@ func TestBuilderFromRequestWithPrefix(t *testing.T) {
}
}
}
func TestIsIPv6Address(t *testing.T) {
for _, tc := range []struct {
name string
address string
isIPv6 bool
}{
{
name: "IPv6 short address",
address: `2607:f0d0:1002:51::4`,
isIPv6: true,
},
{
name: "IPv6 short address enclosed in brackets",
address: "[2607:f0d0:1002:51::4]",
isIPv6: true,
},
{
name: "IPv6 address",
address: `2607:f0d0:1002:0051:0000:0000:0000:0004`,
isIPv6: true,
},
{
name: "IPv6 address with numeric zone ID",
address: `fe80::bd0f:a8bc:6480:238b%11`,
isIPv6: true,
},
{
name: "IPv6 address with device name as zone ID",
address: `fe80::bd0f:a8bc:6480:238b%eth0`,
isIPv6: true,
},
{
name: "IPv6 address with device name as zone ID enclosed in brackets",
address: `[fe80::bd0f:a8bc:6480:238b%eth0]`,
isIPv6: true,
},
{
name: "IPv4-mapped address",
address: "::FFFF:129.144.52.38",
isIPv6: true,
},
{
name: "localhost",
address: "::1",
isIPv6: true,
},
{
name: "localhost",
address: "::1",
isIPv6: true,
},
{
name: "long localhost address",
address: "0:0:0:0:0:0:0:1",
isIPv6: true,
},
{
name: "IPv6 long address with port",
address: "[2607:f0d0:1002:0051:0000:0000:0000:0004]:4321",
isIPv6: false,
},
{
name: "too many groups",
address: "2607:f0d0:1002:0051:0000:0000:0000:0004:4321",
isIPv6: false,
},
{
name: "square brackets don't make an IPv6 address",
address: "[2607:f0d0]",
isIPv6: false,
},
{
name: "require two consecutive colons in localhost",
address: ":1",
isIPv6: false,
},
{
name: "more then 4 hexadecimal digits",
address: "2607:f0d0b:1002:0051:0000:0000:0000:0004",
isIPv6: false,
},
{
name: "too short address",
address: `2607:f0d0:1002:0000:0000:0000:0004`,
isIPv6: false,
},
{
name: "IPv4 address",
address: `192.168.100.1`,
isIPv6: false,
},
{
name: "unclosed bracket",
address: `[2607:f0d0:1002:0051:0000:0000:0000:0004`,
isIPv6: false,
},
{
name: "trailing bracket",
address: `2607:f0d0:1002:0051:0000:0000:0000:0004]`,
isIPv6: false,
},
{
name: "domain name",
address: `localhost`,
isIPv6: false,
},
} {
isIPv6 := isIPv6Address(tc.address)
if isIPv6 && !tc.isIPv6 {
t.Errorf("[%s] address %q falsely detected as IPv6 address", tc.name, tc.address)
} else if !isIPv6 && tc.isIPv6 {
t.Errorf("[%s] address %q not recognized as IPv6", tc.name, tc.address)
}
}
}