feat: add support for tftp download

This adds support for downloading the machine config over TFTP. This
will allow users to avoid having to setup an HTTP server, and use
whatever they are using for PXE.

Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>

go.mod

@@ -50,6 +50,7 @@ require (
 	github.com/opencontainers/image-spec v1.0.1 // indirect
 	github.com/opencontainers/runc v1.0.0-rc8 // indirect
 	github.com/opencontainers/runtime-spec v1.0.1
+	github.com/pin/tftp v2.1.0+incompatible
 	github.com/prometheus/procfs v0.0.6
 	github.com/ryanuber/columnize v2.1.0+incompatible
 	github.com/spf13/cobra v0.0.5

go.sum

@@ -362,6 +362,8 @@ github.com/pborman/uuid v0.0.0-20150603214016-ca53cad383ca h1:dKRMHfduZ/ZqOHuYGk
 github.com/pborman/uuid v0.0.0-20150603214016-ca53cad383ca/go.mod h1:VyrYX9gd7irzKovcSS6BIIEwPRkP2Wm2m9ufcdFSJ34=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
+github.com/pin/tftp v2.1.0+incompatible h1:Yng4J7jv6lOc6IF4XoB5mnd3P7ZrF60XQq+my3FAMus=
+github.com/pin/tftp v2.1.0+incompatible/go.mod h1:xVpZOMCXTy+A5QMjEVN0Glwa1sUvaJhFXbr/aAxuxGY=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=

hack/test/integration/docker-compose.yaml

@@ -10,6 +10,7 @@ services:
         ipv4_address: 172.28.1.1
     volumes:
       - ./dnsmasq/talos0.conf:/etc/dnsmasq.conf:Z
+      - ./dnsmasq/tftpboot:/var/lib/tftpboot
     cap_add:
       - NET_ADMIN
     restart: always

hack/test/integration/libvirt.sh

@@ -53,7 +53,7 @@ function up {
     echo ${INSTALLER}
     cp $PWD/../../../build/initramfs.xz ./matchbox/assets/
     cp $PWD/../../../build/vmlinuz ./matchbox/assets/
-    cd matchbox/assets
+    cd ./matchbox/assets
     $PWD/../../../../../build/osctl-linux-amd64 config generate --install-image ${INSTALLER} integration-test https://kubernetes.talos.dev:6443
     yq w -i init.yaml machine.install.extraKernelArgs[+] 'console=ttyS0'
     yq w -i init.yaml cluster.network.cni.name 'custom'

pkg/download/download.go

@@ -67,8 +67,9 @@ func Download(endpoint string, opts ...Option) (b []byte, err error) {
 		opt(dlOpts)
 	}
 
-	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
-	if err != nil {
+	var req *http.Request
+
+	if req, err = http.NewRequest(http.MethodGet, u.String(), nil); err != nil {
 		return b, err
 	}
 
@@ -82,27 +83,26 @@ func Download(endpoint string, opts ...Option) (b []byte, err error) {
 			return retry.ExpectedError(err)
 		}
 
-		if dlOpts.Format == b64 {
-			var b64 []byte
-
-			b64, err = base64.StdEncoding.DecodeString(string(b))
-			if err != nil {
-				return err
-			}
-
-			b = b64
-		}
-
 		return nil
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to download config from %q: %w", u.String(), err)
 	}
 
+	if dlOpts.Format == b64 {
+		var b64 []byte
+
+		b64, err = base64.StdEncoding.DecodeString(string(b))
+		if err != nil {
+			return nil, err
+		}
+
+		b = b64
+	}
+
 	return b, nil
 }
 
-// download handles the actual http request
 func download(req *http.Request) (data []byte, err error) {
 	client := &http.Client{}
 
@@ -124,3 +124,8 @@ func download(req *http.Request) (data []byte, err error) {
 
 	return data, err
 }
+
+func init() {
+	transport := (http.DefaultTransport.(*http.Transport))
+	transport.RegisterProtocol("tftp", NewTFTPTransport())
+}

pkg/download/tftp.go

@@ -0,0 +1,66 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package download
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/pin/tftp"
+)
+
+// NewTFTPTransport returns an http.RoundTripper capable of handling the TFTP
+// protocol.
+func NewTFTPTransport() http.RoundTripper {
+	return &tftpRoundTripper{}
+}
+
+var _ http.RoundTripper = &tftpRoundTripper{}
+
+type tftpRoundTripper struct{}
+
+func (t *tftpRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	addr := req.URL.Host
+
+	if req.URL.Port() == "" {
+		addr += ":69"
+	}
+
+	c, err := tftp.NewClient(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	w, err := c.Receive(req.URL.Path, "octet")
+	if err != nil {
+		return nil, err
+	}
+
+	buf := &bytes.Buffer{}
+
+	written, err := w.WriteTo(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	if expected, ok := w.(tftp.IncomingTransfer).Size(); ok {
+		if written != expected {
+			return nil, fmt.Errorf("expected %d bytes, got %d", expected, written)
+		}
+	}
+
+	return &http.Response{
+		Status:        "200 OK",
+		StatusCode:    200,
+		Proto:         "TFTP/1.0",
+		ProtoMajor:    1,
+		ProtoMinor:    0,
+		Body:          ioutil.NopCloser(buf),
+		ContentLength: -1,
+		Request:       req,
+	}, nil
+}