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Merge pull request #2447 from tifayuki/cloudfront-s3-filter

Browse source 
add s3 region filters for cloudfront
This commit is contained in:
Derek McGowan 2017-12-07 10:04:35 -08:00 committed by GitHub
commit f411848591
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GPG key ID: 4AEE18F83AFDEB23
11 changed files with 716 additions and 1548 deletions
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1
.gitignore vendored
View file

@ -35,3 +35,4 @@ bin/*
# Editor/IDE specific files.
*.sublime-project
*.sublime-workspace
.idea/*

2
context/logger.go
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@ -39,6 +39,8 @@ type Logger interface {
Warn(args ...interface{})
Warnf(format string, args ...interface{})
Warnln(args ...interface{})
WithError(err error) *logrus.Entry
}
type loggerKey struct{}

16
docs/configuration.md
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@ -183,6 +183,10 @@ middleware:
privatekey: /path/to/pem
keypairid: cloudfrontkeypairid
duration: 3000s
ipfilteredby: awsregion
awsregion: us-east-1, use-east-2
updatefrenquency: 12h
iprangesurl: https://ip-ranges.amazonaws.com/ip-ranges.json
storage:
- name: redirect
options:
@ -636,6 +640,10 @@ middleware:
privatekey: /path/to/pem
keypairid: cloudfrontkeypairid
duration: 3000s
ipfilteredby: awsregion
awsregion: us-east-1, use-east-2
updatefrenquency: 12h
iprangesurl: https://ip-ranges.amazonaws.com/ip-ranges.json
```
Each middleware entry has `name` and `options` entries. The `name` must
@ -655,6 +663,14 @@ interpretation of the options.
| `privatekey` | yes | The private key for Cloudfront, provided by AWS. |
| `keypairid` | yes | The key pair ID provided by AWS. |
| `duration` | no | An integer and unit for the duration of the Cloudfront session. Valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, or `h`. For example, `3000s` is valid, but `3000 s` is not. If you do not specify a `duration` or you specify an integer without a time unit, the duration defaults to `20m` (20 minutes).|
|`ipfilteredby`|no | A string with the following value `none|aws|awsregion`. |
|`awsregion`|no | A comma separated string of AWS regions, only available when `ipfilteredby` is `awsregion`. For example, `us-east-1, us-west-2`|
|`updatefrenquency`|no | The frequency to update AWS IP regions, default: `12h`|
|`iprangesurl`|no | The URL contains the AWS IP ranges information, default: `https://ip-ranges.amazonaws.com/ip-ranges.json`|
Then value of ipfilteredby:
`none`: default, do not filter by IP
`aws`: IP from AWS goes to S3 directly
`awsregion`: IP from certain AWS regions goes to S3 directly, use together with `awsregion`
### `redirect`

79
registry/storage/driver/middleware/cloudfront/middleware.go
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@ -16,7 +16,7 @@ import (
"github.com/aws/aws-sdk-go/service/cloudfront/sign"
dcontext "github.com/docker/distribution/context"
storagedriver "github.com/docker/distribution/registry/storage/driver"
storagemiddleware "github.com/docker/distribution/registry/storage/driver/middleware"
"github.com/docker/distribution/registry/storage/driver/middleware"
)
// cloudFrontStorageMiddleware provides a simple implementation of layerHandler that
@ -24,6 +24,7 @@ import (
// then issues HTTP Temporary Redirects to this CloudFront content URL.
type cloudFrontStorageMiddleware struct {
storagedriver.StorageDriver
awsIPs *awsIPs
urlSigner *sign.URLSigner
baseURL string
duration time.Duration
@ -34,7 +35,13 @@ var _ storagedriver.StorageDriver = &cloudFrontStorageMiddleware{}
// newCloudFrontLayerHandler constructs and returns a new CloudFront
// LayerHandler implementation.
// Required options: baseurl, privatekey, keypairid
// Optional options: ipFilteredBy, awsregion
// ipfilteredby: valid value "none|aws|awsregion". "none", do not filter any IP, default value. "aws", only aws IP goes
// to S3 directly. "awsregion", only regions listed in awsregion options goes to S3 directly
// awsregion: a comma separated string of AWS regions.
func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, options map[string]interface{}) (storagedriver.StorageDriver, error) {
// parse baseurl
base, ok := options["baseurl"]
if !ok {
return nil, fmt.Errorf("no baseurl provided")
@ -52,6 +59,8 @@ func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, o
if _, err := url.Parse(baseURL); err != nil {
return nil, fmt.Errorf("invalid baseurl: %v", err)
}
// parse privatekey to get pkPath
pk, ok := options["privatekey"]
if !ok {
return nil, fmt.Errorf("no privatekey provided")
@ -60,6 +69,8 @@ func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, o
if !ok {
return nil, fmt.Errorf("privatekey must be a string")
}
// parse keypairid
kpid, ok := options["keypairid"]
if !ok {
return nil, fmt.Errorf("no keypairid provided")
@ -69,6 +80,7 @@ func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, o
return nil, fmt.Errorf("keypairid must be a string")
}
// get urlSigner from the file specified in pkPath
pkBytes, err := ioutil.ReadFile(pkPath)
if err != nil {
return nil, fmt.Errorf("failed to read privatekey file: %s", err)
@ -82,12 +94,11 @@ func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, o
if err != nil {
return nil, err
}
urlSigner := sign.NewURLSigner(keypairID, privateKey)
// parse duration
duration := 20 * time.Minute
d, ok := options["duration"]
if ok {
if d, ok := options["duration"]; ok {
switch d := d.(type) {
case time.Duration:
duration = d
@ -100,11 +111,62 @@ func newCloudFrontStorageMiddleware(storageDriver storagedriver.StorageDriver, o
}
}
// parse updatefrenquency
updateFrequency := defaultUpdateFrequency
if u, ok := options["updatefrenquency"]; ok {
switch u := u.(type) {
case time.Duration:
updateFrequency = u
case string:
updateFreq, err := time.ParseDuration(u)
if err != nil {
return nil, fmt.Errorf("invalid updatefrenquency: %s", err)
}
duration = updateFreq
}
}
// parse iprangesurl
ipRangesURL := defaultIPRangesURL
if i, ok := options["iprangesurl"]; ok {
if iprangeurl, ok := i.(string); ok {
ipRangesURL = iprangeurl
} else {
return nil, fmt.Errorf("iprangesurl must be a string")
}
}
// parse ipfilteredby
var awsIPs *awsIPs
if ipFilteredBy := options["ipfilteredby"].(string); ok {
switch strings.ToLower(strings.TrimSpace(ipFilteredBy)) {
case "", "none":
awsIPs = nil
case "aws":
newAWSIPs(ipRangesURL, updateFrequency, nil)
case "awsregion":
var awsRegion []string
if regions, ok := options["awsregion"].(string); ok {
for _, awsRegions := range strings.Split(regions, ",") {
awsRegion = append(awsRegion, strings.ToLower(strings.TrimSpace(awsRegions)))
}
awsIPs = newAWSIPs(ipRangesURL, updateFrequency, awsRegion)
} else {
return nil, fmt.Errorf("awsRegion must be a comma separated string of valid aws regions")
}
default:
return nil, fmt.Errorf("ipfilteredby only allows a string the following value: none|aws|awsregion")
}
} else {
return nil, fmt.Errorf("ipfilteredby only allows a string with the following value: none|aws|awsregion")
}
return &cloudFrontStorageMiddleware{
StorageDriver: storageDriver,
urlSigner: urlSigner,
baseURL: baseURL,
duration: duration,
awsIPs: awsIPs,
}, nil
}
@ -114,8 +176,8 @@ type S3BucketKeyer interface {
S3BucketKey(path string) string
}
// Resolve returns an http.Handler which can serve the contents of the given
// Layer, or an error if not supported by the storagedriver.
// URLFor attempts to find a url which may be used to retrieve the file at the given path.
// Returns an error if the file cannot be found.
func (lh *cloudFrontStorageMiddleware) URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) {
// TODO(endophage): currently only supports S3
keyer, ok := lh.StorageDriver.(S3BucketKeyer)
@ -124,6 +186,11 @@ func (lh *cloudFrontStorageMiddleware) URLFor(ctx context.Context, path string,
return lh.StorageDriver.URLFor(ctx, path, options)
}
if eligibleForS3(ctx, lh.awsIPs) {
return lh.StorageDriver.URLFor(ctx, path, options)
}
// Get signed cloudfront url.
cfURL, err := lh.urlSigner.Sign(lh.baseURL+keyer.S3BucketKey(path), time.Now().Add(lh.duration))
if err != nil {
return "", err

223
registry/storage/driver/middleware/cloudfront/s3filter.go Normal file
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@ -0,0 +1,223 @@
package middleware
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"net"
"net/http"
"strings"
"sync"
"time"
dcontext "github.com/docker/distribution/context"
)
const (
// ipRangesURL is the URL to get definition of AWS IPs
defaultIPRangesURL = "https://ip-ranges.amazonaws.com/ip-ranges.json"
// updateFrequency tells how frequently AWS IPs need to be updated
defaultUpdateFrequency = time.Hour * 12
)
// newAWSIPs returns a New awsIP object.
// If awsRegion is `nil`, it accepts any region. Otherwise, it only allow the regions specified
func newAWSIPs(host string, updateFrequency time.Duration, awsRegion []string) *awsIPs {
ips := &awsIPs{
host: host,
updateFrequency: updateFrequency,
awsRegion: awsRegion,
updaterStopChan: make(chan bool),
}
if err := ips.tryUpdate(); err != nil {
dcontext.GetLogger(context.Background()).WithError(err).Warn("failed to update AWS IP")
}
go ips.updater()
return ips
}
// awsIPs tracks a list of AWS ips, filtered by awsRegion
type awsIPs struct {
host string
updateFrequency time.Duration
ipv4 []net.IPNet
ipv6 []net.IPNet
mutex sync.RWMutex
awsRegion []string
updaterStopChan chan bool
initialized bool
}
type awsIPResponse struct {
Prefixes []prefixEntry `json:"prefixes"`
V6Prefixes []prefixEntry `json:"ipv6_prefixes"`
}
type prefixEntry struct {
IPV4Prefix string `json:"ip_prefix"`
IPV6Prefix string `json:"ipv6_prefix"`
Region string `json:"region"`
Service string `json:"service"`
}
func fetchAWSIPs(url string) (awsIPResponse, error) {
var response awsIPResponse
resp, err := http.Get(url)
if err != nil {
return response, err
}
if resp.StatusCode != 200 {
body, _ := ioutil.ReadAll(resp.Body)
return response, fmt.Errorf("failed to fetch network data. response = %s", body)
}
decoder := json.NewDecoder(resp.Body)
err = decoder.Decode(&response)
if err != nil {
return response, err
}
return response, nil
}
// tryUpdate attempts to download the new set of ip addresses.
// tryUpdate must be thread safe with contains
func (s *awsIPs) tryUpdate() error {
response, err := fetchAWSIPs(s.host)
if err != nil {
return err
}
var ipv4 []net.IPNet
var ipv6 []net.IPNet
processAddress := func(output *[]net.IPNet, prefix string, region string) {
regionAllowed := false
if len(s.awsRegion) > 0 {
for _, ar := range s.awsRegion {
if strings.ToLower(region) == ar {
regionAllowed = true
break
}
}
} else {
regionAllowed = true
}
_, network, err := net.ParseCIDR(prefix)
if err != nil {
dcontext.GetLoggerWithFields(dcontext.Background(), map[interface{}]interface{}{
"cidr": prefix,
}).Error("unparseable cidr")
return
}
if regionAllowed {
*output = append(*output, *network)
}
}
for _, prefix := range response.Prefixes {
processAddress(&ipv4, prefix.IPV4Prefix, prefix.Region)
}
for _, prefix := range response.V6Prefixes {
processAddress(&ipv6, prefix.IPV6Prefix, prefix.Region)
}
s.mutex.Lock()
defer s.mutex.Unlock()
// Update each attr of awsips atomically.
s.ipv4 = ipv4
s.ipv6 = ipv6
s.initialized = true
return nil
}
// This function is meant to be run in a background goroutine.
// It will periodically update the ips from aws.
func (s *awsIPs) updater() {
defer close(s.updaterStopChan)
for {
time.Sleep(s.updateFrequency)
select {
case <-s.updaterStopChan:
dcontext.GetLogger(context.Background()).Info("aws ip updater received stop signal")
return
default:
err := s.tryUpdate()
if err != nil {
dcontext.GetLogger(context.Background()).WithError(err).Error("git AWS IP")
}
}
}
}
// getCandidateNetworks returns either the ipv4 or ipv6 networks
// that were last read from aws. The networks returned
// have the same type as the ip address provided.
func (s *awsIPs) getCandidateNetworks(ip net.IP) []net.IPNet {
s.mutex.RLock()
defer s.mutex.RUnlock()
if ip.To4() != nil {
return s.ipv4
} else if ip.To16() != nil {
return s.ipv6
} else {
dcontext.GetLoggerWithFields(dcontext.Background(), map[interface{}]interface{}{
"ip": ip,
}).Error("unknown ip address format")
// assume mismatch, pass through cloudfront
return nil
}
}
// Contains determines whether the host is within aws.
func (s *awsIPs) contains(ip net.IP) bool {
networks := s.getCandidateNetworks(ip)
for _, network := range networks {
if network.Contains(ip) {
return true
}
}
return false
}
// parseIPFromRequest attempts to extract the ip address of the
// client that made the request
func parseIPFromRequest(ctx context.Context) (net.IP, error) {
request, err := dcontext.GetRequest(ctx)
if err != nil {
return nil, err
}
ipStr := dcontext.RemoteIP(request)
ip := net.ParseIP(ipStr)
if ip == nil {
return nil, fmt.Errorf("invalid ip address from requester: %s", ipStr)
}
return ip, nil
}
// eligibleForS3 checks if a request is eligible for using S3 directly
// Return true only when the IP belongs to a specific aws region and user-agent is docker
func eligibleForS3(ctx context.Context, awsIPs *awsIPs) bool {
if awsIPs != nil && awsIPs.initialized {
if addr, err := parseIPFromRequest(ctx); err == nil {
request, err := dcontext.GetRequest(ctx)
if err != nil {
dcontext.GetLogger(ctx).Warnf("the CloudFront middleware cannot parse the request: %s", err)
} else {
loggerField := map[interface{}]interface{}{
"user-client": request.UserAgent(),
"ip": dcontext.RemoteIP(request),
}
if awsIPs.contains(addr) {
dcontext.GetLoggerWithFields(ctx, loggerField).Info("request from the allowed AWS region, skipping CloudFront")
return true
}
dcontext.GetLoggerWithFields(ctx, loggerField).Warn("request not from the allowed AWS region, fallback to CloudFront")
}
} else {
dcontext.GetLogger(ctx).WithError(err).Warn("failed to parse ip address from context, fallback to CloudFront")
}
}
return false
}

401
registry/storage/driver/middleware/cloudfront/s3filter_test.go Normal file
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@ -0,0 +1,401 @@
package middleware
import (
"context"
"crypto/rand"
"encoding/json"
"fmt"
dcontext "github.com/docker/distribution/context"
"net"
"net/http"
"net/http/httptest"
"testing"
"time"
"reflect" // used as a replacement for testify
)
// Rather than pull in all of testify
func assertEqual(t *testing.T, x, y interface{}) {
if !reflect.DeepEqual(x, y) {
t.Errorf("%s: Not equal! Expected='%v', Actual='%v'\n", t.Name(), x, y)
t.FailNow()
}
}
type mockIPRangeHandler struct {
data awsIPResponse
}
func (m mockIPRangeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
bytes, err := json.Marshal(m.data)
if err != nil {
w.WriteHeader(500)
return
}
w.Write(bytes)
}
func newTestHandler(data awsIPResponse) *httptest.Server {
return httptest.NewServer(mockIPRangeHandler{
data: data,
})
}
func serverIPRanges(server *httptest.Server) string {
return fmt.Sprintf("%s/", server.URL)
}
func setupTest(data awsIPResponse) *httptest.Server {
// This is a basic schema which only claims the exact ip
// is in aws.
server := newTestHandler(data)
return server
}
func TestS3TryUpdate(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{IPV4Prefix: "123.231.123.231/32"},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
assertEqual(t, 1, len(ips.ipv4))
assertEqual(t, 0, len(ips.ipv6))
}
func TestMatchIPV6(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
V6Prefixes: []prefixEntry{
{IPV6Prefix: "ff00::/16"},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
ips.tryUpdate()
assertEqual(t, true, ips.contains(net.ParseIP("ff00::")))
assertEqual(t, 1, len(ips.ipv6))
assertEqual(t, 0, len(ips.ipv4))
}
func TestMatchIPV4(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{IPV4Prefix: "192.168.0.0/24"},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
ips.tryUpdate()
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.0")))
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.1")))
assertEqual(t, false, ips.contains(net.ParseIP("192.169.0.0")))
}
func TestMatchIPV4_2(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{
IPV4Prefix: "192.168.0.0/24",
Region: "us-east-1",
},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
ips.tryUpdate()
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.0")))
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.1")))
assertEqual(t, false, ips.contains(net.ParseIP("192.169.0.0")))
}
func TestMatchIPV4WithRegionMatched(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{
IPV4Prefix: "192.168.0.0/24",
Region: "us-east-1",
},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, []string{"us-east-1"})
ips.tryUpdate()
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.0")))
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.1")))
assertEqual(t, false, ips.contains(net.ParseIP("192.169.0.0")))
}
func TestMatchIPV4WithRegionMatch_2(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{
IPV4Prefix: "192.168.0.0/24",
Region: "us-east-1",
},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, []string{"us-west-2", "us-east-1"})
ips.tryUpdate()
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.0")))
assertEqual(t, true, ips.contains(net.ParseIP("192.168.0.1")))
assertEqual(t, false, ips.contains(net.ParseIP("192.169.0.0")))
}
func TestMatchIPV4WithRegionNotMatched(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{
IPV4Prefix: "192.168.0.0/24",
Region: "us-east-1",
},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, []string{"us-west-2"})
ips.tryUpdate()
assertEqual(t, false, ips.contains(net.ParseIP("192.168.0.0")))
assertEqual(t, false, ips.contains(net.ParseIP("192.168.0.1")))
assertEqual(t, false, ips.contains(net.ParseIP("192.169.0.0")))
}
func TestInvalidData(t *testing.T) {
t.Parallel()
// Invalid entries from aws should be ignored.
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{IPV4Prefix: "9000"},
{IPV4Prefix: "192.168.0.0/24"},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
ips.tryUpdate()
assertEqual(t, 1, len(ips.ipv4))
}
func TestInvalidNetworkType(t *testing.T) {
t.Parallel()
server := setupTest(awsIPResponse{
Prefixes: []prefixEntry{
{IPV4Prefix: "192.168.0.0/24"},
},
V6Prefixes: []prefixEntry{
{IPV6Prefix: "ff00::/8"},
{IPV6Prefix: "fe00::/8"},
},
})
defer server.Close()
ips := newAWSIPs(serverIPRanges(server), time.Hour, nil)
assertEqual(t, 0, len(ips.getCandidateNetworks(make([]byte, 17)))) // 17 bytes does not correspond to any net type
assertEqual(t, 1, len(ips.getCandidateNetworks(make([]byte, 4)))) // netv4 networks
assertEqual(t, 2, len(ips.getCandidateNetworks(make([]byte, 16)))) // netv6 networks
}
func TestParsing(t *testing.T) {
var data = `{
"prefixes": [{
"ip_prefix": "192.168.0.0",
"region": "someregion",
"service": "s3"}],
"ipv6_prefixes": [{
"ipv6_prefix": "2001:4860:4860::8888",
"region": "anotherregion",
"service": "ec2"}]
}`
rawMockHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Write([]byte(data)) })
t.Parallel()
server := httptest.NewServer(rawMockHandler)
defer server.Close()
schema, err := fetchAWSIPs(server.URL)
assertEqual(t, nil, err)
assertEqual(t, 1, len(schema.Prefixes))
assertEqual(t, prefixEntry{
IPV4Prefix: "192.168.0.0",
Region: "someregion",
Service: "s3",
}, schema.Prefixes[0])
assertEqual(t, 1, len(schema.V6Prefixes))
assertEqual(t, prefixEntry{
IPV6Prefix: "2001:4860:4860::8888",
Region: "anotherregion",
Service: "ec2",
}, schema.V6Prefixes[0])
}
func TestUpdateCalledRegularly(t *testing.T) {
t.Parallel()
updateCount := 0
server := httptest.NewServer(http.HandlerFunc(
func(rw http.ResponseWriter, req *http.Request) {
updateCount++
rw.Write([]byte("ok"))
}))
defer server.Close()
newAWSIPs(fmt.Sprintf("%s/", server.URL), time.Second, nil)
time.Sleep(time.Second*4 + time.Millisecond*500)
if updateCount < 4 {
t.Errorf("Update should have been called at least 4 times, actual=%d", updateCount)
}
}
func TestEligibleForS3(t *testing.T) {
awsIPs := &awsIPs{
ipv4: []net.IPNet{{
IP: net.ParseIP("192.168.1.1"),
Mask: net.IPv4Mask(255, 255, 255, 0),
}},
initialized: true,
}
empty := context.TODO()
makeContext := func(ip string) context.Context {
req := &http.Request{
RemoteAddr: ip,
}
return dcontext.WithRequest(empty, req)
}
cases := []struct {
Context context.Context
Expected bool
}{
{Context: empty, Expected: false},
{Context: makeContext("192.168.1.2"), Expected: true},
{Context: makeContext("192.168.0.2"), Expected: false},
}
for _, testCase := range cases {
name := fmt.Sprintf("Client IP = %v",
testCase.Context.Value("http.request.ip"))
t.Run(name, func(t *testing.T) {
assertEqual(t, testCase.Expected, eligibleForS3(testCase.Context, awsIPs))
})
}
}
func TestEligibleForS3WithAWSIPNotInitialized(t *testing.T) {
awsIPs := &awsIPs{
ipv4: []net.IPNet{{
IP: net.ParseIP("192.168.1.1"),
Mask: net.IPv4Mask(255, 255, 255, 0),
}},
initialized: false,
}
empty := context.TODO()
makeContext := func(ip string) context.Context {
req := &http.Request{
RemoteAddr: ip,
}
return dcontext.WithRequest(empty, req)
}
cases := []struct {
Context context.Context
Expected bool
}{
{Context: empty, Expected: false},
{Context: makeContext("192.168.1.2"), Expected: false},
{Context: makeContext("192.168.0.2"), Expected: false},
}
for _, testCase := range cases {
name := fmt.Sprintf("Client IP = %v",
testCase.Context.Value("http.request.ip"))
t.Run(name, func(t *testing.T) {
assertEqual(t, testCase.Expected, eligibleForS3(testCase.Context, awsIPs))
})
}
}
// populate ips with a number of different ipv4 and ipv6 networks, for the purposes
// of benchmarking contains() performance.
func populateRandomNetworks(b *testing.B, ips *awsIPs, ipv4Count, ipv6Count int) {
generateNetworks := func(dest *[]net.IPNet, bytes int, count int) {
for i := 0; i < count; i++ {
ip := make([]byte, bytes)
_, err := rand.Read(ip)
if err != nil {
b.Fatalf("failed to generate network for test : %s", err.Error())
}
mask := make([]byte, bytes)
for i := 0; i < bytes; i++ {
mask[i] = 0xff
}
*dest = append(*dest, net.IPNet{
IP: ip,
Mask: mask,
})
}
}
generateNetworks(&ips.ipv4, 4, ipv4Count)
generateNetworks(&ips.ipv6, 16, ipv6Count)
}
func BenchmarkContainsRandom(b *testing.B) {
// Generate a random network configuration, of size comparable to
// aws official networks list
// curl -s https://ip-ranges.amazonaws.com/ip-ranges.json | jq '.prefixes | length'
// 941
numNetworksPerType := 1000 // keep in sync with the above
// intentionally skip constructor when creating awsIPs, to avoid updater routine.
// This benchmark is only concerned with contains() performance.
awsIPs := awsIPs{}
populateRandomNetworks(b, &awsIPs, numNetworksPerType, numNetworksPerType)
ipv4 := make([][]byte, b.N)
ipv6 := make([][]byte, b.N)
for i := 0; i < b.N; i++ {
ipv4[i] = make([]byte, 4)
ipv6[i] = make([]byte, 16)
rand.Read(ipv4[i])
rand.Read(ipv6[i])
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
awsIPs.contains(ipv4[i])
awsIPs.contains(ipv6[i])
}
}
func BenchmarkContainsProd(b *testing.B) {
awsIPs := newAWSIPs(defaultIPRangesURL, defaultUpdateFrequency, nil)
ipv4 := make([][]byte, b.N)
ipv6 := make([][]byte, b.N)
for i := 0; i < b.N; i++ {
ipv4[i] = make([]byte, 4)
ipv6[i] = make([]byte, 16)
rand.Read(ipv4[i])
rand.Read(ipv6[i])
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
awsIPs.contains(ipv4[i])
awsIPs.contains(ipv6[i])
}
}

340
vendor/github.com/miekg/dns/msg_generate.go generated vendored
View file

@ -1,340 +0,0 @@
//+build ignore
// msg_generate.go is meant to run with go generate. It will use
// go/{importer,types} to track down all the RR struct types. Then for each type
// it will generate pack/unpack methods based on the struct tags. The generated source is
// written to zmsg.go, and is meant to be checked into git.
package main
import (
"bytes"
"fmt"
"go/format"
"go/importer"
"go/types"
"log"
"os"
"strings"
)
var packageHdr = `
// *** DO NOT MODIFY ***
// AUTOGENERATED BY go generate from msg_generate.go
package dns
`
// getTypeStruct will take a type and the package scope, and return the
// (innermost) struct if the type is considered a RR type (currently defined as
// those structs beginning with a RR_Header, could be redefined as implementing
// the RR interface). The bool return value indicates if embedded structs were
// resolved.
func getTypeStruct(t types.Type, scope *types.Scope) (*types.Struct, bool) {
st, ok := t.Underlying().(*types.Struct)
if !ok {
return nil, false
}
if st.Field(0).Type() == scope.Lookup("RR_Header").Type() {
return st, false
}
if st.Field(0).Anonymous() {
st, _ := getTypeStruct(st.Field(0).Type(), scope)
return st, true
}
return nil, false
}
func main() {
// Import and type-check the package
pkg, err := importer.Default().Import("github.com/miekg/dns")
fatalIfErr(err)
scope := pkg.Scope()
// Collect actual types (*X)
var namedTypes []string
for _, name := range scope.Names() {
o := scope.Lookup(name)
if o == nil || !o.Exported() {
continue
}
if st, _ := getTypeStruct(o.Type(), scope); st == nil {
continue
}
if name == "PrivateRR" {
continue
}
// Check if corresponding TypeX exists
if scope.Lookup("Type"+o.Name()) == nil && o.Name() != "RFC3597" {
log.Fatalf("Constant Type%s does not exist.", o.Name())
}
namedTypes = append(namedTypes, o.Name())
}
b := &bytes.Buffer{}
b.WriteString(packageHdr)
fmt.Fprint(b, "// pack*() functions\n\n")
for _, name := range namedTypes {
o := scope.Lookup(name)
st, _ := getTypeStruct(o.Type(), scope)
fmt.Fprintf(b, "func (rr *%s) pack(msg []byte, off int, compression map[string]int, compress bool) (int, error) {\n", name)
fmt.Fprint(b, `off, err := rr.Hdr.pack(msg, off, compression, compress)
if err != nil {
return off, err
}
headerEnd := off
`)
for i := 1; i < st.NumFields(); i++ {
o := func(s string) {
fmt.Fprintf(b, s, st.Field(i).Name())
fmt.Fprint(b, `if err != nil {
return off, err
}
`)
}
if _, ok := st.Field(i).Type().(*types.Slice); ok {
switch st.Tag(i) {
case `dns:"-"`: // ignored
case `dns:"txt"`:
o("off, err = packStringTxt(rr.%s, msg, off)\n")
case `dns:"opt"`:
o("off, err = packDataOpt(rr.%s, msg, off)\n")
case `dns:"nsec"`:
o("off, err = packDataNsec(rr.%s, msg, off)\n")
case `dns:"domain-name"`:
o("off, err = packDataDomainNames(rr.%s, msg, off, compression, compress)\n")
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
continue
}
switch {
case st.Tag(i) == `dns:"-"`: // ignored
case st.Tag(i) == `dns:"cdomain-name"`:
fallthrough
case st.Tag(i) == `dns:"domain-name"`:
o("off, err = PackDomainName(rr.%s, msg, off, compression, compress)\n")
case st.Tag(i) == `dns:"a"`:
o("off, err = packDataA(rr.%s, msg, off)\n")
case st.Tag(i) == `dns:"aaaa"`:
o("off, err = packDataAAAA(rr.%s, msg, off)\n")
case st.Tag(i) == `dns:"uint48"`:
o("off, err = packUint48(rr.%s, msg, off)\n")
case st.Tag(i) == `dns:"txt"`:
o("off, err = packString(rr.%s, msg, off)\n")
case strings.HasPrefix(st.Tag(i), `dns:"size-base32`): // size-base32 can be packed just like base32
fallthrough
case st.Tag(i) == `dns:"base32"`:
o("off, err = packStringBase32(rr.%s, msg, off)\n")
case strings.HasPrefix(st.Tag(i), `dns:"size-base64`): // size-base64 can be packed just like base64
fallthrough
case st.Tag(i) == `dns:"base64"`:
o("off, err = packStringBase64(rr.%s, msg, off)\n")
case strings.HasPrefix(st.Tag(i), `dns:"size-hex:SaltLength`): // Hack to fix empty salt length for NSEC3
o("if rr.%s == \"-\" { /* do nothing, empty salt */ }\n")
continue
case strings.HasPrefix(st.Tag(i), `dns:"size-hex`): // size-hex can be packed just like hex
fallthrough
case st.Tag(i) == `dns:"hex"`:
o("off, err = packStringHex(rr.%s, msg, off)\n")
case st.Tag(i) == `dns:"octet"`:
o("off, err = packStringOctet(rr.%s, msg, off)\n")
case st.Tag(i) == "":
switch st.Field(i).Type().(*types.Basic).Kind() {
case types.Uint8:
o("off, err = packUint8(rr.%s, msg, off)\n")
case types.Uint16:
o("off, err = packUint16(rr.%s, msg, off)\n")
case types.Uint32:
o("off, err = packUint32(rr.%s, msg, off)\n")
case types.Uint64:
o("off, err = packUint64(rr.%s, msg, off)\n")
case types.String:
o("off, err = packString(rr.%s, msg, off)\n")
default:
log.Fatalln(name, st.Field(i).Name())
}
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
}
// We have packed everything, only now we know the rdlength of this RR
fmt.Fprintln(b, "rr.Header().Rdlength = uint16(off-headerEnd)")
fmt.Fprintln(b, "return off, nil }\n")
}
fmt.Fprint(b, "// unpack*() functions\n\n")
for _, name := range namedTypes {
o := scope.Lookup(name)
st, _ := getTypeStruct(o.Type(), scope)
fmt.Fprintf(b, "func unpack%s(h RR_Header, msg []byte, off int) (RR, int, error) {\n", name)
fmt.Fprintf(b, "rr := new(%s)\n", name)
fmt.Fprint(b, "rr.Hdr = h\n")
fmt.Fprint(b, `if noRdata(h) {
return rr, off, nil
}
var err error
rdStart := off
_ = rdStart
`)
for i := 1; i < st.NumFields(); i++ {
o := func(s string) {
fmt.Fprintf(b, s, st.Field(i).Name())
fmt.Fprint(b, `if err != nil {
return rr, off, err
}
`)
}
// size-* are special, because they reference a struct member we should use for the length.
if strings.HasPrefix(st.Tag(i), `dns:"size-`) {
structMember := structMember(st.Tag(i))
structTag := structTag(st.Tag(i))
switch structTag {
case "hex":
fmt.Fprintf(b, "rr.%s, off, err = unpackStringHex(msg, off, off + int(rr.%s))\n", st.Field(i).Name(), structMember)
case "base32":
fmt.Fprintf(b, "rr.%s, off, err = unpackStringBase32(msg, off, off + int(rr.%s))\n", st.Field(i).Name(), structMember)
case "base64":
fmt.Fprintf(b, "rr.%s, off, err = unpackStringBase64(msg, off, off + int(rr.%s))\n", st.Field(i).Name(), structMember)
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
fmt.Fprint(b, `if err != nil {
return rr, off, err
}
`)
continue
}
if _, ok := st.Field(i).Type().(*types.Slice); ok {
switch st.Tag(i) {
case `dns:"-"`: // ignored
case `dns:"txt"`:
o("rr.%s, off, err = unpackStringTxt(msg, off)\n")
case `dns:"opt"`:
o("rr.%s, off, err = unpackDataOpt(msg, off)\n")
case `dns:"nsec"`:
o("rr.%s, off, err = unpackDataNsec(msg, off)\n")
case `dns:"domain-name"`:
o("rr.%s, off, err = unpackDataDomainNames(msg, off, rdStart + int(rr.Hdr.Rdlength))\n")
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
continue
}
switch st.Tag(i) {
case `dns:"-"`: // ignored
case `dns:"cdomain-name"`:
fallthrough
case `dns:"domain-name"`:
o("rr.%s, off, err = UnpackDomainName(msg, off)\n")
case `dns:"a"`:
o("rr.%s, off, err = unpackDataA(msg, off)\n")
case `dns:"aaaa"`:
o("rr.%s, off, err = unpackDataAAAA(msg, off)\n")
case `dns:"uint48"`:
o("rr.%s, off, err = unpackUint48(msg, off)\n")
case `dns:"txt"`:
o("rr.%s, off, err = unpackString(msg, off)\n")
case `dns:"base32"`:
o("rr.%s, off, err = unpackStringBase32(msg, off, rdStart + int(rr.Hdr.Rdlength))\n")
case `dns:"base64"`:
o("rr.%s, off, err = unpackStringBase64(msg, off, rdStart + int(rr.Hdr.Rdlength))\n")
case `dns:"hex"`:
o("rr.%s, off, err = unpackStringHex(msg, off, rdStart + int(rr.Hdr.Rdlength))\n")
case `dns:"octet"`:
o("rr.%s, off, err = unpackStringOctet(msg, off)\n")
case "":
switch st.Field(i).Type().(*types.Basic).Kind() {
case types.Uint8:
o("rr.%s, off, err = unpackUint8(msg, off)\n")
case types.Uint16:
o("rr.%s, off, err = unpackUint16(msg, off)\n")
case types.Uint32:
o("rr.%s, off, err = unpackUint32(msg, off)\n")
case types.Uint64:
o("rr.%s, off, err = unpackUint64(msg, off)\n")
case types.String:
o("rr.%s, off, err = unpackString(msg, off)\n")
default:
log.Fatalln(name, st.Field(i).Name())
}
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
// If we've hit len(msg) we return without error.
if i < st.NumFields()-1 {
fmt.Fprintf(b, `if off == len(msg) {
return rr, off, nil
}
`)
}
}
fmt.Fprintf(b, "return rr, off, err }\n\n")
}
// Generate typeToUnpack map
fmt.Fprintln(b, "var typeToUnpack = map[uint16]func(RR_Header, []byte, int) (RR, int, error){")
for _, name := range namedTypes {
if name == "RFC3597" {
continue
}
fmt.Fprintf(b, "Type%s: unpack%s,\n", name, name)
}
fmt.Fprintln(b, "}\n")
// gofmt
res, err := format.Source(b.Bytes())
if err != nil {
b.WriteTo(os.Stderr)
log.Fatal(err)
}
// write result
f, err := os.Create("zmsg.go")
fatalIfErr(err)
defer f.Close()
f.Write(res)
}
// structMember will take a tag like dns:"size-base32:SaltLength" and return the last part of this string.
func structMember(s string) string {
fields := strings.Split(s, ":")
if len(fields) == 0 {
return ""
}
f := fields[len(fields)-1]
// f should have a closing "
if len(f) > 1 {
return f[:len(f)-1]
}
return f
}
// structTag will take a tag like dns:"size-base32:SaltLength" and return base32.
func structTag(s string) string {
fields := strings.Split(s, ":")
if len(fields) < 2 {
return ""
}
return fields[1][len("\"size-"):]
}
func fatalIfErr(err error) {
if err != nil {
log.Fatal(err)
}
}

271
vendor/github.com/miekg/dns/types_generate.go generated vendored
View file

@ -1,271 +0,0 @@
//+build ignore
// types_generate.go is meant to run with go generate. It will use
// go/{importer,types} to track down all the RR struct types. Then for each type
// it will generate conversion tables (TypeToRR and TypeToString) and banal
// methods (len, Header, copy) based on the struct tags. The generated source is
// written to ztypes.go, and is meant to be checked into git.
package main
import (
"bytes"
"fmt"
"go/format"
"go/importer"
"go/types"
"log"
"os"
"strings"
"text/template"
)
var skipLen = map[string]struct{}{
"NSEC": {},
"NSEC3": {},
"OPT": {},
}
var packageHdr = `
// *** DO NOT MODIFY ***
// AUTOGENERATED BY go generate from type_generate.go
package dns
import (
"encoding/base64"
"net"
)
`
var TypeToRR = template.Must(template.New("TypeToRR").Parse(`
// TypeToRR is a map of constructors for each RR type.
var TypeToRR = map[uint16]func() RR{
{{range .}}{{if ne . "RFC3597"}} Type{{.}}: func() RR { return new({{.}}) },
{{end}}{{end}} }
`))
var typeToString = template.Must(template.New("typeToString").Parse(`
// TypeToString is a map of strings for each RR type.
var TypeToString = map[uint16]string{
{{range .}}{{if ne . "NSAPPTR"}} Type{{.}}: "{{.}}",
{{end}}{{end}} TypeNSAPPTR: "NSAP-PTR",
}
`))
var headerFunc = template.Must(template.New("headerFunc").Parse(`
// Header() functions
{{range .}} func (rr *{{.}}) Header() *RR_Header { return &rr.Hdr }
{{end}}
`))
// getTypeStruct will take a type and the package scope, and return the
// (innermost) struct if the type is considered a RR type (currently defined as
// those structs beginning with a RR_Header, could be redefined as implementing
// the RR interface). The bool return value indicates if embedded structs were
// resolved.
func getTypeStruct(t types.Type, scope *types.Scope) (*types.Struct, bool) {
st, ok := t.Underlying().(*types.Struct)
if !ok {
return nil, false
}
if st.Field(0).Type() == scope.Lookup("RR_Header").Type() {
return st, false
}
if st.Field(0).Anonymous() {
st, _ := getTypeStruct(st.Field(0).Type(), scope)
return st, true
}
return nil, false
}
func main() {
// Import and type-check the package
pkg, err := importer.Default().Import("github.com/miekg/dns")
fatalIfErr(err)
scope := pkg.Scope()
// Collect constants like TypeX
var numberedTypes []string
for _, name := range scope.Names() {
o := scope.Lookup(name)
if o == nil || !o.Exported() {
continue
}
b, ok := o.Type().(*types.Basic)
if !ok || b.Kind() != types.Uint16 {
continue
}
if !strings.HasPrefix(o.Name(), "Type") {
continue
}
name := strings.TrimPrefix(o.Name(), "Type")
if name == "PrivateRR" {
continue
}
numberedTypes = append(numberedTypes, name)
}
// Collect actual types (*X)
var namedTypes []string
for _, name := range scope.Names() {
o := scope.Lookup(name)
if o == nil || !o.Exported() {
continue
}
if st, _ := getTypeStruct(o.Type(), scope); st == nil {
continue
}
if name == "PrivateRR" {
continue
}
// Check if corresponding TypeX exists
if scope.Lookup("Type"+o.Name()) == nil && o.Name() != "RFC3597" {
log.Fatalf("Constant Type%s does not exist.", o.Name())
}
namedTypes = append(namedTypes, o.Name())
}
b := &bytes.Buffer{}
b.WriteString(packageHdr)
// Generate TypeToRR
fatalIfErr(TypeToRR.Execute(b, namedTypes))
// Generate typeToString
fatalIfErr(typeToString.Execute(b, numberedTypes))
// Generate headerFunc
fatalIfErr(headerFunc.Execute(b, namedTypes))
// Generate len()
fmt.Fprint(b, "// len() functions\n")
for _, name := range namedTypes {
if _, ok := skipLen[name]; ok {
continue
}
o := scope.Lookup(name)
st, isEmbedded := getTypeStruct(o.Type(), scope)
if isEmbedded {
continue
}
fmt.Fprintf(b, "func (rr *%s) len() int {\n", name)
fmt.Fprintf(b, "l := rr.Hdr.len()\n")
for i := 1; i < st.NumFields(); i++ {
o := func(s string) { fmt.Fprintf(b, s, st.Field(i).Name()) }
if _, ok := st.Field(i).Type().(*types.Slice); ok {
switch st.Tag(i) {
case `dns:"-"`:
// ignored
case `dns:"cdomain-name"`, `dns:"domain-name"`, `dns:"txt"`:
o("for _, x := range rr.%s { l += len(x) + 1 }\n")
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
continue
}
switch {
case st.Tag(i) == `dns:"-"`:
// ignored
case st.Tag(i) == `dns:"cdomain-name"`, st.Tag(i) == `dns:"domain-name"`:
o("l += len(rr.%s) + 1\n")
case st.Tag(i) == `dns:"octet"`:
o("l += len(rr.%s)\n")
case strings.HasPrefix(st.Tag(i), `dns:"size-base64`):
fallthrough
case st.Tag(i) == `dns:"base64"`:
o("l += base64.StdEncoding.DecodedLen(len(rr.%s))\n")
case strings.HasPrefix(st.Tag(i), `dns:"size-hex`):
fallthrough
case st.Tag(i) == `dns:"hex"`:
o("l += len(rr.%s)/2 + 1\n")
case st.Tag(i) == `dns:"a"`:
o("l += net.IPv4len // %s\n")
case st.Tag(i) == `dns:"aaaa"`:
o("l += net.IPv6len // %s\n")
case st.Tag(i) == `dns:"txt"`:
o("for _, t := range rr.%s { l += len(t) + 1 }\n")
case st.Tag(i) == `dns:"uint48"`:
o("l += 6 // %s\n")
case st.Tag(i) == "":
switch st.Field(i).Type().(*types.Basic).Kind() {
case types.Uint8:
o("l += 1 // %s\n")
case types.Uint16:
o("l += 2 // %s\n")
case types.Uint32:
o("l += 4 // %s\n")
case types.Uint64:
o("l += 8 // %s\n")
case types.String:
o("l += len(rr.%s) + 1\n")
default:
log.Fatalln(name, st.Field(i).Name())
}
default:
log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
}
}
fmt.Fprintf(b, "return l }\n")
}
// Generate copy()
fmt.Fprint(b, "// copy() functions\n")
for _, name := range namedTypes {
o := scope.Lookup(name)
st, isEmbedded := getTypeStruct(o.Type(), scope)
if isEmbedded {
continue
}
fmt.Fprintf(b, "func (rr *%s) copy() RR {\n", name)
fields := []string{"*rr.Hdr.copyHeader()"}
for i := 1; i < st.NumFields(); i++ {
f := st.Field(i).Name()
if sl, ok := st.Field(i).Type().(*types.Slice); ok {
t := sl.Underlying().String()
t = strings.TrimPrefix(t, "[]")
if strings.Contains(t, ".") {
splits := strings.Split(t, ".")
t = splits[len(splits)-1]
}
fmt.Fprintf(b, "%s := make([]%s, len(rr.%s)); copy(%s, rr.%s)\n",
f, t, f, f, f)
fields = append(fields, f)
continue
}
if st.Field(i).Type().String() == "net.IP" {
fields = append(fields, "copyIP(rr."+f+")")
continue
}
fields = append(fields, "rr."+f)
}
fmt.Fprintf(b, "return &%s{%s}\n", name, strings.Join(fields, ","))
fmt.Fprintf(b, "}\n")
}
// gofmt
res, err := format.Source(b.Bytes())
if err != nil {
b.WriteTo(os.Stderr)
log.Fatal(err)
}
// write result
f, err := os.Create("ztypes.go")
fatalIfErr(err)
defer f.Close()
f.Write(res)
}
func fatalIfErr(err error) {
if err != nil {
log.Fatal(err)
}
}

68
vendor/golang.org/x/net/idna/idna.go generated vendored
View file

@ -1,68 +0,0 @@
// Copyright 2012 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 idna implements IDNA2008 (Internationalized Domain Names for
// Applications), defined in RFC 5890, RFC 5891, RFC 5892, RFC 5893 and
// RFC 5894.
package idna // import "golang.org/x/net/idna"
import (
"strings"
"unicode/utf8"
)
// TODO(nigeltao): specify when errors occur. For example, is ToASCII(".") or
// ToASCII("foo\x00") an error? See also http://www.unicode.org/faq/idn.html#11
// acePrefix is the ASCII Compatible Encoding prefix.
const acePrefix = "xn--"
// ToASCII converts a domain or domain label to its ASCII form. For example,
// ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
// ToASCII("golang") is "golang".
func ToASCII(s string) (string, error) {
if ascii(s) {
return s, nil
}
labels := strings.Split(s, ".")
for i, label := range labels {
if !ascii(label) {
a, err := encode(acePrefix, label)
if err != nil {
return "", err
}
labels[i] = a
}
}
return strings.Join(labels, "."), nil
}
// ToUnicode converts a domain or domain label to its Unicode form. For example,
// ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and
// ToUnicode("golang") is "golang".
func ToUnicode(s string) (string, error) {
if !strings.Contains(s, acePrefix) {
return s, nil
}
labels := strings.Split(s, ".")
for i, label := range labels {
if strings.HasPrefix(label, acePrefix) {
u, err := decode(label[len(acePrefix):])
if err != nil {
return "", err
}
labels[i] = u
}
}
return strings.Join(labels, "."), nil
}
func ascii(s string) bool {
for i := 0; i < len(s); i++ {
if s[i] >= utf8.RuneSelf {
return false
}
}
return true
}

200
vendor/golang.org/x/net/idna/punycode.go generated vendored
View file

@ -1,200 +0,0 @@
// Copyright 2012 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 idna
// This file implements the Punycode algorithm from RFC 3492.
import (
"fmt"
"math"
"strings"
"unicode/utf8"
)
// These parameter values are specified in section 5.
//
// All computation is done with int32s, so that overflow behavior is identical
// regardless of whether int is 32-bit or 64-bit.
const (
base int32 = 36
damp int32 = 700
initialBias int32 = 72
initialN int32 = 128
skew int32 = 38
tmax int32 = 26
tmin int32 = 1
)
// decode decodes a string as specified in section 6.2.
func decode(encoded string) (string, error) {
if encoded == "" {
return "", nil
}
pos := 1 + strings.LastIndex(encoded, "-")
if pos == 1 {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
if pos == len(encoded) {
return encoded[:len(encoded)-1], nil
}
output := make([]rune, 0, len(encoded))
if pos != 0 {
for _, r := range encoded[:pos-1] {
output = append(output, r)
}
}
i, n, bias := int32(0), initialN, initialBias
for pos < len(encoded) {
oldI, w := i, int32(1)
for k := base; ; k += base {
if pos == len(encoded) {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
digit, ok := decodeDigit(encoded[pos])
if !ok {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
pos++
i += digit * w
if i < 0 {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
t := k - bias
if t < tmin {
t = tmin
} else if t > tmax {
t = tmax
}
if digit < t {
break
}
w *= base - t
if w >= math.MaxInt32/base {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
}
x := int32(len(output) + 1)
bias = adapt(i-oldI, x, oldI == 0)
n += i / x
i %= x
if n > utf8.MaxRune || len(output) >= 1024 {
return "", fmt.Errorf("idna: invalid label %q", encoded)
}
output = append(output, 0)
copy(output[i+1:], output[i:])
output[i] = n
i++
}
return string(output), nil
}
// encode encodes a string as specified in section 6.3 and prepends prefix to
// the result.
//
// The "while h < length(input)" line in the specification becomes "for
// remaining != 0" in the Go code, because len(s) in Go is in bytes, not runes.
func encode(prefix, s string) (string, error) {
output := make([]byte, len(prefix), len(prefix)+1+2*len(s))
copy(output, prefix)
delta, n, bias := int32(0), initialN, initialBias
b, remaining := int32(0), int32(0)
for _, r := range s {
if r < 0x80 {
b++
output = append(output, byte(r))
} else {
remaining++
}
}
h := b
if b > 0 {
output = append(output, '-')
}
for remaining != 0 {
m := int32(0x7fffffff)
for _, r := range s {
if m > r && r >= n {
m = r
}
}
delta += (m - n) * (h + 1)
if delta < 0 {
return "", fmt.Errorf("idna: invalid label %q", s)
}
n = m
for _, r := range s {
if r < n {
delta++
if delta < 0 {
return "", fmt.Errorf("idna: invalid label %q", s)
}
continue
}
if r > n {
continue
}
q := delta
for k := base; ; k += base {
t := k - bias
if t < tmin {
t = tmin
} else if t > tmax {
t = tmax
}
if q < t {
break
}
output = append(output, encodeDigit(t+(q-t)%(base-t)))
q = (q - t) / (base - t)
}
output = append(output, encodeDigit(q))
bias = adapt(delta, h+1, h == b)
delta = 0
h++
remaining--
}
delta++
n++
}
return string(output), nil
}
func decodeDigit(x byte) (digit int32, ok bool) {
switch {
case '0' <= x && x <= '9':
return int32(x - ('0' - 26)), true
case 'A' <= x && x <= 'Z':
return int32(x - 'A'), true
case 'a' <= x && x <= 'z':
return int32(x - 'a'), true
}
return 0, false
}
func encodeDigit(digit int32) byte {
switch {
case 0 <= digit && digit < 26:
return byte(digit + 'a')
case 26 <= digit && digit < 36:
return byte(digit + ('0' - 26))
}
panic("idna: internal error in punycode encoding")
}
// adapt is the bias adaptation function specified in section 6.1.
func adapt(delta, numPoints int32, firstTime bool) int32 {
if firstTime {
delta /= damp
} else {
delta /= 2
}
delta += delta / numPoints
k := int32(0)
for delta > ((base-tmin)*tmax)/2 {
delta /= base - tmin
k += base
}
return k + (base-tmin+1)*delta/(delta+skew)
}

663
vendor/golang.org/x/net/publicsuffix/gen.go generated vendored
View file

@ -1,663 +0,0 @@
// Copyright 2012 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.
// +build ignore
package main
// This program generates table.go and table_test.go.
// Invoke as:
//
// go run gen.go -version "xxx" >table.go
// go run gen.go -version "xxx" -test >table_test.go
//
// Pass -v to print verbose progress information.
//
// The version is derived from information found at
// https://github.com/publicsuffix/list/commits/master/public_suffix_list.dat
//
// To fetch a particular git revision, such as 5c70ccd250, pass
// -url "https://raw.githubusercontent.com/publicsuffix/list/5c70ccd250/public_suffix_list.dat"
import (
"bufio"
"bytes"
"flag"
"fmt"
"go/format"
"io"
"net/http"
"os"
"regexp"
"sort"
"strings"
"golang.org/x/net/idna"
)
const (
// These sum of these four values must be no greater than 32.
nodesBitsChildren = 9
nodesBitsICANN = 1
nodesBitsTextOffset = 15
nodesBitsTextLength = 6
// These sum of these four values must be no greater than 32.
childrenBitsWildcard = 1
childrenBitsNodeType = 2
childrenBitsHi = 14
childrenBitsLo = 14
)
var (
maxChildren int
maxTextOffset int
maxTextLength int
maxHi uint32
maxLo uint32
)
func max(a, b int) int {
if a < b {
return b
}
return a
}
func u32max(a, b uint32) uint32 {
if a < b {
return b
}
return a
}
const (
nodeTypeNormal = 0
nodeTypeException = 1
nodeTypeParentOnly = 2
numNodeType = 3
)
func nodeTypeStr(n int) string {
switch n {
case nodeTypeNormal:
return "+"
case nodeTypeException:
return "!"
case nodeTypeParentOnly:
return "o"
}
panic("unreachable")
}
var (
labelEncoding = map[string]uint32{}
labelsList = []string{}
labelsMap = map[string]bool{}
rules = []string{}
// validSuffix is used to check that the entries in the public suffix list
// are in canonical form (after Punycode encoding). Specifically, capital
// letters are not allowed.
validSuffix = regexp.MustCompile(`^[a-z0-9_\!\*\-\.]+$`)
subset = flag.Bool("subset", false, "generate only a subset of the full table, for debugging")
url = flag.String("url",
"https://publicsuffix.org/list/effective_tld_names.dat",
"URL of the publicsuffix.org list. If empty, stdin is read instead")
v = flag.Bool("v", false, "verbose output (to stderr)")
version = flag.String("version", "", "the effective_tld_names.dat version")
test = flag.Bool("test", false, "generate table_test.go")
)
func main() {
if err := main1(); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}
func main1() error {
flag.Parse()
if nodesBitsTextLength+nodesBitsTextOffset+nodesBitsICANN+nodesBitsChildren > 32 {
return fmt.Errorf("not enough bits to encode the nodes table")
}
if childrenBitsLo+childrenBitsHi+childrenBitsNodeType+childrenBitsWildcard > 32 {
return fmt.Errorf("not enough bits to encode the children table")
}
if *version == "" {
return fmt.Errorf("-version was not specified")
}
var r io.Reader = os.Stdin
if *url != "" {
res, err := http.Get(*url)
if err != nil {
return err
}
if res.StatusCode != http.StatusOK {
return fmt.Errorf("bad GET status for %s: %d", *url, res.Status)
}
r = res.Body
defer res.Body.Close()
}
var root node
icann := false
buf := new(bytes.Buffer)
br := bufio.NewReader(r)
for {
s, err := br.ReadString('\n')
if err != nil {
if err == io.EOF {
break
}
return err
}
s = strings.TrimSpace(s)
if strings.Contains(s, "BEGIN ICANN DOMAINS") {
icann = true
continue
}
if strings.Contains(s, "END ICANN DOMAINS") {
icann = false
continue
}
if s == "" || strings.HasPrefix(s, "//") {
continue
}
s, err = idna.ToASCII(s)
if err != nil {
return err
}
if !validSuffix.MatchString(s) {
return fmt.Errorf("bad publicsuffix.org list data: %q", s)
}
if *subset {
switch {
case s == "ac.jp" || strings.HasSuffix(s, ".ac.jp"):
case s == "ak.us" || strings.HasSuffix(s, ".ak.us"):
case s == "ao" || strings.HasSuffix(s, ".ao"):
case s == "ar" || strings.HasSuffix(s, ".ar"):
case s == "arpa" || strings.HasSuffix(s, ".arpa"):
case s == "cy" || strings.HasSuffix(s, ".cy"):
case s == "dyndns.org" || strings.HasSuffix(s, ".dyndns.org"):
case s == "jp":
case s == "kobe.jp" || strings.HasSuffix(s, ".kobe.jp"):
case s == "kyoto.jp" || strings.HasSuffix(s, ".kyoto.jp"):
case s == "om" || strings.HasSuffix(s, ".om"):
case s == "uk" || strings.HasSuffix(s, ".uk"):
case s == "uk.com" || strings.HasSuffix(s, ".uk.com"):
case s == "tw" || strings.HasSuffix(s, ".tw"):
case s == "zw" || strings.HasSuffix(s, ".zw"):
case s == "xn--p1ai" || strings.HasSuffix(s, ".xn--p1ai"):
// xn--p1ai is Russian-Cyrillic "рф".
default:
continue
}
}
rules = append(rules, s)
nt, wildcard := nodeTypeNormal, false
switch {
case strings.HasPrefix(s, "*."):
s, nt = s[2:], nodeTypeParentOnly
wildcard = true
case strings.HasPrefix(s, "!"):
s, nt = s[1:], nodeTypeException
}
labels := strings.Split(s, ".")
for n, i := &root, len(labels)-1; i >= 0; i-- {
label := labels[i]
n = n.child(label)
if i == 0 {
if nt != nodeTypeParentOnly && n.nodeType == nodeTypeParentOnly {
n.nodeType = nt
}
n.icann = n.icann && icann
n.wildcard = n.wildcard || wildcard
}
labelsMap[label] = true
}
}
labelsList = make([]string, 0, len(labelsMap))
for label := range labelsMap {
labelsList = append(labelsList, label)
}
sort.Strings(labelsList)
p := printReal
if *test {
p = printTest
}
if err := p(buf, &root); err != nil {
return err
}
b, err := format.Source(buf.Bytes())
if err != nil {
return err
}
_, err = os.Stdout.Write(b)
return err
}
func printTest(w io.Writer, n *node) error {
fmt.Fprintf(w, "// generated by go run gen.go; DO NOT EDIT\n\n")
fmt.Fprintf(w, "package publicsuffix\n\nvar rules = [...]string{\n")
for _, rule := range rules {
fmt.Fprintf(w, "%q,\n", rule)
}
fmt.Fprintf(w, "}\n\nvar nodeLabels = [...]string{\n")
if err := n.walk(w, printNodeLabel); err != nil {
return err
}
fmt.Fprintf(w, "}\n")
return nil
}
func printReal(w io.Writer, n *node) error {
const header = `// generated by go run gen.go; DO NOT EDIT
package publicsuffix
const version = %q
const (
nodesBitsChildren = %d
nodesBitsICANN = %d
nodesBitsTextOffset = %d
nodesBitsTextLength = %d
childrenBitsWildcard = %d
childrenBitsNodeType = %d
childrenBitsHi = %d
childrenBitsLo = %d
)
const (
nodeTypeNormal = %d
nodeTypeException = %d
nodeTypeParentOnly = %d
)
// numTLD is the number of top level domains.
const numTLD = %d
`
fmt.Fprintf(w, header, *version,
nodesBitsChildren, nodesBitsICANN, nodesBitsTextOffset, nodesBitsTextLength,
childrenBitsWildcard, childrenBitsNodeType, childrenBitsHi, childrenBitsLo,
nodeTypeNormal, nodeTypeException, nodeTypeParentOnly, len(n.children))
text := combineText(labelsList)
if text == "" {
return fmt.Errorf("internal error: makeText returned no text")
}
for _, label := range labelsList {
offset, length := strings.Index(text, label), len(label)
if offset < 0 {
return fmt.Errorf("internal error: could not find %q in text %q", label, text)
}
maxTextOffset, maxTextLength = max(maxTextOffset, offset), max(maxTextLength, length)
if offset >= 1<<nodesBitsTextOffset {
return fmt.Errorf("text offset %d is too large, or nodeBitsTextOffset is too small", offset)
}
if length >= 1<<nodesBitsTextLength {
return fmt.Errorf("text length %d is too large, or nodeBitsTextLength is too small", length)
}
labelEncoding[label] = uint32(offset)<<nodesBitsTextLength | uint32(length)
}
fmt.Fprintf(w, "// Text is the combined text of all labels.\nconst text = ")
for len(text) > 0 {
n, plus := len(text), ""
if n > 64 {
n, plus = 64, " +"
}
fmt.Fprintf(w, "%q%s\n", text[:n], plus)
text = text[n:]
}
if err := n.walk(w, assignIndexes); err != nil {
return err
}
fmt.Fprintf(w, `
// nodes is the list of nodes. Each node is represented as a uint32, which
// encodes the node's children, wildcard bit and node type (as an index into
// the children array), ICANN bit and text.
//
// In the //-comment after each node's data, the nodes indexes of the children
// are formatted as (n0x1234-n0x1256), with * denoting the wildcard bit. The
// nodeType is printed as + for normal, ! for exception, and o for parent-only
// nodes that have children but don't match a domain label in their own right.
// An I denotes an ICANN domain.
//
// The layout within the uint32, from MSB to LSB, is:
// [%2d bits] unused
// [%2d bits] children index
// [%2d bits] ICANN bit
// [%2d bits] text index
// [%2d bits] text length
var nodes = [...]uint32{
`,
32-nodesBitsChildren-nodesBitsICANN-nodesBitsTextOffset-nodesBitsTextLength,
nodesBitsChildren, nodesBitsICANN, nodesBitsTextOffset, nodesBitsTextLength)
if err := n.walk(w, printNode); err != nil {
return err
}
fmt.Fprintf(w, `}
// children is the list of nodes' children, the parent's wildcard bit and the
// parent's node type. If a node has no children then their children index
// will be in the range [0, 6), depending on the wildcard bit and node type.
//
// The layout within the uint32, from MSB to LSB, is:
// [%2d bits] unused
// [%2d bits] wildcard bit
// [%2d bits] node type
// [%2d bits] high nodes index (exclusive) of children
// [%2d bits] low nodes index (inclusive) of children
var children=[...]uint32{
`,
32-childrenBitsWildcard-childrenBitsNodeType-childrenBitsHi-childrenBitsLo,
childrenBitsWildcard, childrenBitsNodeType, childrenBitsHi, childrenBitsLo)
for i, c := range childrenEncoding {
s := "---------------"
lo := c & (1<<childrenBitsLo - 1)
hi := (c >> childrenBitsLo) & (1<<childrenBitsHi - 1)
if lo != hi {
s = fmt.Sprintf("n0x%04x-n0x%04x", lo, hi)
}
nodeType := int(c>>(childrenBitsLo+childrenBitsHi)) & (1<<childrenBitsNodeType - 1)
wildcard := c>>(childrenBitsLo+childrenBitsHi+childrenBitsNodeType) != 0
fmt.Fprintf(w, "0x%08x, // c0x%04x (%s)%s %s\n",
c, i, s, wildcardStr(wildcard), nodeTypeStr(nodeType))
}
fmt.Fprintf(w, "}\n\n")
fmt.Fprintf(w, "// max children %d (capacity %d)\n", maxChildren, 1<<nodesBitsChildren-1)
fmt.Fprintf(w, "// max text offset %d (capacity %d)\n", maxTextOffset, 1<<nodesBitsTextOffset-1)
fmt.Fprintf(w, "// max text length %d (capacity %d)\n", maxTextLength, 1<<nodesBitsTextLength-1)
fmt.Fprintf(w, "// max hi %d (capacity %d)\n", maxHi, 1<<childrenBitsHi-1)
fmt.Fprintf(w, "// max lo %d (capacity %d)\n", maxLo, 1<<childrenBitsLo-1)
return nil
}
type node struct {
label string
nodeType int
icann bool
wildcard bool
// nodesIndex and childrenIndex are the index of this node in the nodes
// and the index of its children offset/length in the children arrays.
nodesIndex, childrenIndex int
// firstChild is the index of this node's first child, or zero if this
// node has no children.
firstChild int
// children are the node's children, in strictly increasing node label order.
children []*node
}
func (n *node) walk(w io.Writer, f func(w1 io.Writer, n1 *node) error) error {
if err := f(w, n); err != nil {
return err
}
for _, c := range n.children {
if err := c.walk(w, f); err != nil {
return err
}
}
return nil
}
// child returns the child of n with the given label. The child is created if
// it did not exist beforehand.
func (n *node) child(label string) *node {
for _, c := range n.children {
if c.label == label {
return c
}
}
c := &node{
label: label,
nodeType: nodeTypeParentOnly,
icann: true,
}
n.children = append(n.children, c)
sort.Sort(byLabel(n.children))
return c
}
type byLabel []*node
func (b byLabel) Len() int { return len(b) }
func (b byLabel) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
func (b byLabel) Less(i, j int) bool { return b[i].label < b[j].label }
var nextNodesIndex int
// childrenEncoding are the encoded entries in the generated children array.
// All these pre-defined entries have no children.
var childrenEncoding = []uint32{
0 << (childrenBitsLo + childrenBitsHi), // Without wildcard bit, nodeTypeNormal.
1 << (childrenBitsLo + childrenBitsHi), // Without wildcard bit, nodeTypeException.
2 << (childrenBitsLo + childrenBitsHi), // Without wildcard bit, nodeTypeParentOnly.
4 << (childrenBitsLo + childrenBitsHi), // With wildcard bit, nodeTypeNormal.
5 << (childrenBitsLo + childrenBitsHi), // With wildcard bit, nodeTypeException.
6 << (childrenBitsLo + childrenBitsHi), // With wildcard bit, nodeTypeParentOnly.
}
var firstCallToAssignIndexes = true
func assignIndexes(w io.Writer, n *node) error {
if len(n.children) != 0 {
// Assign nodesIndex.
n.firstChild = nextNodesIndex
for _, c := range n.children {
c.nodesIndex = nextNodesIndex
nextNodesIndex++
}
// The root node's children is implicit.
if firstCallToAssignIndexes {
firstCallToAssignIndexes = false
return nil
}
// Assign childrenIndex.
maxChildren = max(maxChildren, len(childrenEncoding))
if len(childrenEncoding) >= 1<<nodesBitsChildren {
return fmt.Errorf("children table size %d is too large, or nodeBitsChildren is too small", len(childrenEncoding))
}
n.childrenIndex = len(childrenEncoding)
lo := uint32(n.firstChild)
hi := lo + uint32(len(n.children))
maxLo, maxHi = u32max(maxLo, lo), u32max(maxHi, hi)
if lo >= 1<<childrenBitsLo {
return fmt.Errorf("children lo %d is too large, or childrenBitsLo is too small", lo)
}
if hi >= 1<<childrenBitsHi {
return fmt.Errorf("children hi %d is too large, or childrenBitsHi is too small", hi)
}
enc := hi<<childrenBitsLo | lo
enc |= uint32(n.nodeType) << (childrenBitsLo + childrenBitsHi)
if n.wildcard {
enc |= 1 << (childrenBitsLo + childrenBitsHi + childrenBitsNodeType)
}
childrenEncoding = append(childrenEncoding, enc)
} else {
n.childrenIndex = n.nodeType
if n.wildcard {
n.childrenIndex += numNodeType
}
}
return nil
}
func printNode(w io.Writer, n *node) error {
for _, c := range n.children {
s := "---------------"
if len(c.children) != 0 {
s = fmt.Sprintf("n0x%04x-n0x%04x", c.firstChild, c.firstChild+len(c.children))
}
encoding := labelEncoding[c.label]
if c.icann {
encoding |= 1 << (nodesBitsTextLength + nodesBitsTextOffset)
}
encoding |= uint32(c.childrenIndex) << (nodesBitsTextLength + nodesBitsTextOffset + nodesBitsICANN)
fmt.Fprintf(w, "0x%08x, // n0x%04x c0x%04x (%s)%s %s %s %s\n",
encoding, c.nodesIndex, c.childrenIndex, s, wildcardStr(c.wildcard),
nodeTypeStr(c.nodeType), icannStr(c.icann), c.label,
)
}
return nil
}
func printNodeLabel(w io.Writer, n *node) error {
for _, c := range n.children {
fmt.Fprintf(w, "%q,\n", c.label)
}
return nil
}
func icannStr(icann bool) string {
if icann {
return "I"
}
return " "
}
func wildcardStr(wildcard bool) string {
if wildcard {
return "*"
}
return " "
}
// combineText combines all the strings in labelsList to form one giant string.
// Overlapping strings will be merged: "arpa" and "parliament" could yield
// "arparliament".
func combineText(labelsList []string) string {
beforeLength := 0
for _, s := range labelsList {
beforeLength += len(s)
}
text := crush(removeSubstrings(labelsList))
if *v {
fmt.Fprintf(os.Stderr, "crushed %d bytes to become %d bytes\n", beforeLength, len(text))
}
return text
}
type byLength []string
func (s byLength) Len() int { return len(s) }
func (s byLength) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s byLength) Less(i, j int) bool { return len(s[i]) < len(s[j]) }
// removeSubstrings returns a copy of its input with any strings removed
// that are substrings of other provided strings.
func removeSubstrings(input []string) []string {
// Make a copy of input.
ss := append(make([]string, 0, len(input)), input...)
sort.Sort(byLength(ss))
for i, shortString := range ss {
// For each string, only consider strings higher than it in sort order, i.e.
// of equal length or greater.
for _, longString := range ss[i+1:] {
if strings.Contains(longString, shortString) {
ss[i] = ""
break
}
}
}
// Remove the empty strings.
sort.Strings(ss)
for len(ss) > 0 && ss[0] == "" {
ss = ss[1:]
}
return ss
}
// crush combines a list of strings, taking advantage of overlaps. It returns a
// single string that contains each input string as a substring.
func crush(ss []string) string {
maxLabelLen := 0
for _, s := range ss {
if maxLabelLen < len(s) {
maxLabelLen = len(s)
}
}
for prefixLen := maxLabelLen; prefixLen > 0; prefixLen-- {
prefixes := makePrefixMap(ss, prefixLen)
for i, s := range ss {
if len(s) <= prefixLen {
continue
}
mergeLabel(ss, i, prefixLen, prefixes)
}
}
return strings.Join(ss, "")
}
// mergeLabel merges the label at ss[i] with the first available matching label
// in prefixMap, where the last "prefixLen" characters in ss[i] match the first
// "prefixLen" characters in the matching label.
// It will merge ss[i] repeatedly until no more matches are available.
// All matching labels merged into ss[i] are replaced by "".
func mergeLabel(ss []string, i, prefixLen int, prefixes prefixMap) {
s := ss[i]
suffix := s[len(s)-prefixLen:]
for _, j := range prefixes[suffix] {
// Empty strings mean "already used." Also avoid merging with self.
if ss[j] == "" || i == j {
continue
}
if *v {
fmt.Fprintf(os.Stderr, "%d-length overlap at (%4d,%4d): %q and %q share %q\n",
prefixLen, i, j, ss[i], ss[j], suffix)
}
ss[i] += ss[j][prefixLen:]
ss[j] = ""
// ss[i] has a new suffix, so merge again if possible.
// Note: we only have to merge again at the same prefix length. Shorter
// prefix lengths will be handled in the next iteration of crush's for loop.
// Can there be matches for longer prefix lengths, introduced by the merge?
// I believe that any such matches would by necessity have been eliminated
// during substring removal or merged at a higher prefix length. For
// instance, in crush("abc", "cde", "bcdef"), combining "abc" and "cde"
// would yield "abcde", which could be merged with "bcdef." However, in
// practice "cde" would already have been elimintated by removeSubstrings.
mergeLabel(ss, i, prefixLen, prefixes)
return
}
}
// prefixMap maps from a prefix to a list of strings containing that prefix. The
// list of strings is represented as indexes into a slice of strings stored
// elsewhere.
type prefixMap map[string][]int
// makePrefixMap constructs a prefixMap from a slice of strings.
func makePrefixMap(ss []string, prefixLen int) prefixMap {
prefixes := make(prefixMap)
for i, s := range ss {
// We use < rather than <= because if a label matches on a prefix equal to
// its full length, that's actually a substring match handled by
// removeSubstrings.
if prefixLen < len(s) {
prefix := s[:prefixLen]
prefixes[prefix] = append(prefixes[prefix], i)
}
}
return prefixes
}