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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package tsconsensus
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"log"
"net/http"
"time"
"tailscale.com/util/httpm"
)
type joinRequest struct {
RemoteHost string
RemoteID string
}
type commandClient struct {
port uint16
httpClient *http.Client
}
func (rac *commandClient) url(host string, path string) string {
return fmt.Sprintf("http://%s:%d%s", host, rac.port, path)
}
const maxBodyBytes = 1024 * 1024
func readAllMaxBytes(r io.Reader) ([]byte, error) {
return io.ReadAll(io.LimitReader(r, maxBodyBytes+1))
}
func (rac *commandClient) join(host string, jr joinRequest) error {
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
rBs, err := json.Marshal(jr)
if err != nil {
return err
}
url := rac.url(host, "/join")
req, err := http.NewRequestWithContext(ctx, httpm.POST, url, bytes.NewReader(rBs))
if err != nil {
return err
}
resp, err := rac.httpClient.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
respBs, err := readAllMaxBytes(resp.Body)
if err != nil {
return err
}
return fmt.Errorf("remote responded %d: %s", resp.StatusCode, string(respBs))
}
return nil
}
func (rac *commandClient) executeCommand(host string, bs []byte) (CommandResult, error) {
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
url := rac.url(host, "/executeCommand")
req, err := http.NewRequestWithContext(ctx, httpm.POST, url, bytes.NewReader(bs))
if err != nil {
return CommandResult{}, err
}
resp, err := rac.httpClient.Do(req)
if err != nil {
return CommandResult{}, err
}
defer resp.Body.Close()
respBs, err := readAllMaxBytes(resp.Body)
if err != nil {
return CommandResult{}, err
}
if resp.StatusCode != 200 {
return CommandResult{}, fmt.Errorf("remote responded %d: %s", resp.StatusCode, string(respBs))
}
var cr CommandResult
if err = json.Unmarshal(respBs, &cr); err != nil {
return CommandResult{}, err
}
return cr, nil
}
type authedHandler struct {
auth *authorization
handler http.Handler
}
func (h authedHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
err := h.auth.Refresh(r.Context())
if err != nil {
log.Printf("error authedHandler ServeHTTP refresh auth: %v", err)
http.Error(w, "", http.StatusInternalServerError)
return
}
a, err := addrFromServerAddress(r.RemoteAddr)
if err != nil {
log.Printf("error authedHandler ServeHTTP refresh auth: %v", err)
http.Error(w, "", http.StatusInternalServerError)
return
}
allowed := h.auth.AllowsHost(a)
if !allowed {
http.Error(w, "peer not allowed", http.StatusForbidden)
return
}
h.handler.ServeHTTP(w, r)
}
func (c *Consensus) handleJoinHTTP(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
decoder := json.NewDecoder(http.MaxBytesReader(w, r.Body, maxBodyBytes+1))
var jr joinRequest
err := decoder.Decode(&jr)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
_, err = decoder.Token()
if !errors.Is(err, io.EOF) {
http.Error(w, "Request body must only contain a single JSON object", http.StatusBadRequest)
return
}
if jr.RemoteHost == "" {
http.Error(w, "Required: remoteAddr", http.StatusBadRequest)
return
}
if jr.RemoteID == "" {
http.Error(w, "Required: remoteID", http.StatusBadRequest)
return
}
err = c.handleJoin(jr)
if err != nil {
log.Printf("join handler error: %v", err)
http.Error(w, "", http.StatusInternalServerError)
return
}
}
func (c *Consensus) handleExecuteCommandHTTP(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
decoder := json.NewDecoder(r.Body)
var cmd Command
err := decoder.Decode(&cmd)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
result, err := c.executeCommandLocally(cmd)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if err := json.NewEncoder(w).Encode(result); err != nil {
log.Printf("error encoding execute command result: %v", err)
return
}
}
func (c *Consensus) makeCommandMux() *http.ServeMux {
mux := http.NewServeMux()
mux.HandleFunc("POST /join", c.handleJoinHTTP)
mux.HandleFunc("POST /executeCommand", c.handleExecuteCommandHTTP)
return mux
}
func (c *Consensus) makeCommandHandler(auth *authorization) http.Handler {
return authedHandler{
handler: c.makeCommandMux(),
auth: auth,
}
}
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