client/tailscale: move API client for the control admin API

This was work done Nov-Dec 2020 by @c22wen and @chungdaniel.

This is just moving it to another repo.

Co-Authored-By: Christina Wen <37028905+c22wen@users.noreply.github.com>
Co-Authored-By: Christina Wen <christina@tailscale.com>
Co-Authored-By: Daniel Chung <chungdaniel@users.noreply.github.com>
Co-Authored-By: Daniel Chung <daniel@tailscale.com>

Change-Id: I6da3b05b972b54771f796b5be82de5aa463635ca
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

client/tailscale/routes.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"inet.af/netaddr"
+)
+
+// Routes contains the lists of subnet routes that are currently advertised by a device,
+// as well as the subnets that are enabled to be routed by the device.
+type Routes struct {
+	AdvertisedRoutes []netaddr.IPPrefix `json:"advertisedRoutes"`
+	EnabledRoutes    []netaddr.IPPrefix `json:"enabledRoutes"`
+}
+
+// Routes retrieves the list of subnet routes that have been enabled for a device.
+// The routes that are returned are not necessarily advertised by the device,
+// they have only been preapproved.
+func (c *Client) Routes(ctx context.Context, deviceID string) (routes *Routes, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.Routes: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/device/%s/routes", c.BaseURL, deviceID)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	var sr Routes
+	err = json.Unmarshal(b, &sr)
+	return &sr, err
+}
+
+type postRoutesParams struct {
+	Routes []netaddr.IPPrefix `json:"routes"`
+}
+
+// SetRoutes updates the list of subnets that are enabled for a device.
+// Subnets must be parsable by inet.af/netaddr.ParseIPPrefix.
+// Subnets do not have to be currently advertised by a device, they may be pre-enabled.
+// Returns the updated list of enabled and advertised subnet routes in a *Routes object.
+func (c *Client) SetRoutes(ctx context.Context, deviceID string, subnets []netaddr.IPPrefix) (routes *Routes, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetRoutes: %w", err)
+		}
+	}()
+	params := &postRoutesParams{Routes: subnets}
+	data, err := json.Marshal(params)
+	if err != nil {
+		return nil, err
+	}
+	path := fmt.Sprintf("%s/api/v2/device/%s/routes", c.BaseURL, deviceID)
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(data))
+	if err != nil {
+		return nil, err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	var srr *Routes
+	if err := json.Unmarshal(b, &srr); err != nil {
+		return nil, err
+	}
+	return srr, err
+}