feat: download metadata on Scaleway using low source port

This feature allow to us use low source port <1024 to make a http calls.

Signed-off-by: Serge Logvinov <serge.logvinov@sinextra.dev>
Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

go.mod

@@ -59,6 +59,7 @@ require (
 	github.com/google/uuid v1.3.0
 	github.com/gosuri/uiprogress v0.0.1
 	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
+	github.com/hashicorp/go-cleanhttp v0.5.2
 	github.com/hashicorp/go-getter v1.5.11
 	github.com/hashicorp/go-multierror v1.1.1
 	github.com/hashicorp/go-version v1.4.0
@@ -188,7 +189,6 @@ require (
 	github.com/gosuri/uilive v0.0.4 // indirect
 	github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
-	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-immutable-radix v1.3.1 // indirect
 	github.com/hashicorp/go-memdb v1.3.2 // indirect
 	github.com/hashicorp/go-safetemp v1.0.0 // indirect

internal/app/machined/pkg/runtime/v1alpha1/platform/scaleway/scaleway.go

@@ -24,6 +24,8 @@ import (
 const (
 	// ScalewayMetadataEndpoint is the local Scaleway endpoint.
 	ScalewayMetadataEndpoint = "http://169.254.42.42/conf?format=json"
+	// ScalewayUserDataEndpoint is the local Scaleway endpoint for the config.
+	ScalewayUserDataEndpoint = "http://169.254.42.42/user_data/cloud-init"
 )
 
 // Scaleway is the concrete type that implements the runtime.Platform interface.
@@ -125,11 +127,10 @@ func (s *Scaleway) ParseMetadata(metadataConfig *instance.Metadata) (*runtime.Pl
 
 // Configuration implements the runtime.Platform interface.
 func (s *Scaleway) Configuration(ctx context.Context) ([]byte, error) {
-	log.Printf("fetching machine config from scaleway metadata server")
+	log.Printf("fetching machine config from %q", ScalewayUserDataEndpoint)
 
-	instanceAPI := instance.NewMetadataAPI()
+	machineConfigDl, err := download.Download(ctx, ScalewayUserDataEndpoint,
-
+		download.WithLowSrcPort())
-	machineConfigDl, err := instanceAPI.GetUserData("cloud-init")
 	if err != nil {
 		return nil, errors.ErrNoConfigSource
 	}

pkg/download/download.go

@@ -9,10 +9,14 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io/ioutil"
+	"math/rand"
+	"net"
 	"net/http"
 	"net/url"
+	"strconv"
 	"time"
 
+	"github.com/hashicorp/go-cleanhttp"
 	"github.com/talos-systems/go-retry/retry"
 )
 
@@ -21,6 +25,7 @@ const b64 = "base64"
 type downloadOptions struct {
 	Headers    map[string]string
 	Format     string
+	LowSrcPort bool
 
 	ErrorOnNotFound      error
 	ErrorOnEmptyResponse error
@@ -57,6 +62,14 @@ func WithHeaders(headers map[string]string) Option {
 	}
 }
 
+// WithLowSrcPort sets low source port to download
+// the config.
+func WithLowSrcPort() Option {
+	return func(d *downloadOptions) {
+		d.LowSrcPort = true
+	}
+}
+
 // WithErrorOnNotFound provides specific error to return when response has HTTP 404 error.
 func WithErrorOnNotFound(e error) Option {
 	return func(d *downloadOptions) {
@@ -130,6 +143,25 @@ func Download(ctx context.Context, endpoint string, opts ...Option) (b []byte, e
 func download(req *http.Request, dlOpts *downloadOptions) (data []byte, err error) {
 	client := &http.Client{}
 
+	if dlOpts.LowSrcPort {
+		port := 100 + rand.Intn(512)
+
+		localTCPAddr, tcperr := net.ResolveTCPAddr("tcp", ":"+strconv.Itoa(port))
+		if tcperr != nil {
+			return nil, retry.ExpectedError(fmt.Errorf("resolving source tcp address: %s", tcperr.Error()))
+		}
+
+		d := (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+			LocalAddr: localTCPAddr,
+		}).DialContext
+
+		client.Transport = cleanhttp.DefaultTransport()
+		client.Transport.(*http.Transport).DialContext = d
+	}
+
 	resp, err := client.Do(req)
 	if err != nil {
 		return data, retry.ExpectedError(err)