537 lines
13 KiB
Go
537 lines
13 KiB
Go
// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
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//go:generate go run genassets.go gui auto/gui.go
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package main
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import (
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"bytes"
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"compress/gzip"
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"crypto/tls"
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"encoding/json"
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"flag"
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"fmt"
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"io/ioutil"
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"log"
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"math/rand"
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"mime"
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"net"
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"net/http"
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"net/url"
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"path/filepath"
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"strings"
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"time"
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"github.com/golang/groupcache/lru"
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"github.com/juju/ratelimit"
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"github.com/oschwald/geoip2-golang"
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"github.com/syncthing/relaypoolsrv/auto"
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"github.com/syncthing/syncthing/lib/relay/client"
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"github.com/syncthing/syncthing/lib/sync"
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"github.com/syncthing/syncthing/lib/tlsutil"
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)
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type location struct {
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Latitude float64 `json:"latitude"`
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Longitude float64 `json:"longitude"`
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}
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type relay struct {
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URL string `json:"url"`
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Location location `json:"location"`
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uri *url.URL
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}
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func (r relay) String() string {
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return r.URL
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}
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type request struct {
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relay relay
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uri *url.URL
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result chan result
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}
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type result struct {
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err error
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eviction time.Duration
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}
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var (
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binDir string
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testCert tls.Certificate
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listen string = ":80"
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dir string = ""
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evictionTime time.Duration = time.Hour
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debug bool = false
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getLRUSize int = 10 << 10
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getLimitBurst int64 = 10
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getLimitAvg = 1
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postLRUSize int = 1 << 10
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postLimitBurst int64 = 2
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postLimitAvg = 1
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getLimit time.Duration
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postLimit time.Duration
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permRelaysFile string
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ipHeader string
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geoipPath string
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getMut sync.RWMutex = sync.NewRWMutex()
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getLRUCache *lru.Cache
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postMut sync.RWMutex = sync.NewRWMutex()
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postLRUCache *lru.Cache
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requests = make(chan request, 10)
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mut sync.RWMutex = sync.NewRWMutex()
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knownRelays []relay = make([]relay, 0)
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permanentRelays []relay = make([]relay, 0)
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evictionTimers map[string]*time.Timer = make(map[string]*time.Timer)
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)
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func main() {
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flag.StringVar(&listen, "listen", listen, "Listen address")
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flag.StringVar(&dir, "keys", dir, "Directory where http-cert.pem and http-key.pem is stored for TLS listening")
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flag.BoolVar(&debug, "debug", debug, "Enable debug output")
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flag.DurationVar(&evictionTime, "eviction", evictionTime, "After how long the relay is evicted")
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flag.IntVar(&getLRUSize, "get-limit-cache", getLRUSize, "Get request limiter cache size")
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flag.IntVar(&getLimitAvg, "get-limit-avg", 2, "Allowed average get request rate, per 10 s")
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flag.Int64Var(&getLimitBurst, "get-limit-burst", getLimitBurst, "Allowed burst get requests")
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flag.IntVar(&postLRUSize, "post-limit-cache", postLRUSize, "Post request limiter cache size")
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flag.IntVar(&postLimitAvg, "post-limit-avg", 2, "Allowed average post request rate, per minute")
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flag.Int64Var(&postLimitBurst, "post-limit-burst", postLimitBurst, "Allowed burst post requests")
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flag.StringVar(&permRelaysFile, "perm-relays", "", "Path to list of permanent relays")
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flag.StringVar(&ipHeader, "ip-header", "", "Name of header which holds clients ip:port. Only meaningful when running behind a reverse proxy.")
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flag.StringVar(&geoipPath, "geoip", "GeoLite2-City.mmdb", "Path to GeoLite2-City database")
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flag.Parse()
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getLimit = 10 * time.Second / time.Duration(getLimitAvg)
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postLimit = time.Minute / time.Duration(postLimitAvg)
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getLRUCache = lru.New(getLRUSize)
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postLRUCache = lru.New(postLRUSize)
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var listener net.Listener
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var err error
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if permRelaysFile != "" {
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loadPermanentRelays(permRelaysFile)
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}
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testCert = createTestCertificate()
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go requestProcessor()
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if dir != "" {
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if debug {
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log.Println("Starting TLS listener on", listen)
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}
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certFile, keyFile := filepath.Join(dir, "http-cert.pem"), filepath.Join(dir, "http-key.pem")
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cert, err := tls.LoadX509KeyPair(certFile, keyFile)
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if err != nil {
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log.Fatalln("Failed to load HTTP X509 key pair:", err)
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}
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tlsCfg := &tls.Config{
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Certificates: []tls.Certificate{cert},
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MinVersion: tls.VersionTLS10, // No SSLv3
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CipherSuites: []uint16{
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// No RC4
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tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
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tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
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tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
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tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
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tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
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tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
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tls.TLS_RSA_WITH_AES_128_CBC_SHA,
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tls.TLS_RSA_WITH_AES_256_CBC_SHA,
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tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
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tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
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},
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}
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listener, err = tls.Listen("tcp", listen, tlsCfg)
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} else {
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if debug {
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log.Println("Starting plain listener on", listen)
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}
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listener, err = net.Listen("tcp", listen)
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}
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if err != nil {
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log.Fatalln("listen:", err)
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}
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handler := http.NewServeMux()
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handler.HandleFunc("/", handleAssets)
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handler.HandleFunc("/endpoint", handleRequest)
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srv := http.Server{
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Handler: handler,
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ReadTimeout: 10 * time.Second,
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}
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err = srv.Serve(listener)
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if err != nil {
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log.Fatalln("serve:", err)
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}
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}
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func handleAssets(w http.ResponseWriter, r *http.Request) {
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assets := auto.Assets()
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path := r.URL.Path[1:]
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if path == "" {
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path = "index.html"
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}
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bs, ok := assets[path]
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if !ok {
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w.WriteHeader(http.StatusNotFound)
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return
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}
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mtype := mimeTypeForFile(path)
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if len(mtype) != 0 {
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w.Header().Set("Content-Type", mtype)
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}
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if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
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w.Header().Set("Content-Encoding", "gzip")
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} else {
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// ungzip if browser not send gzip accepted header
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var gr *gzip.Reader
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gr, _ = gzip.NewReader(bytes.NewReader(bs))
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bs, _ = ioutil.ReadAll(gr)
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gr.Close()
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}
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w.Header().Set("Content-Length", fmt.Sprintf("%d", len(bs)))
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w.Write(bs)
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}
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func mimeTypeForFile(file string) string {
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// We use a built in table of the common types since the system
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// TypeByExtension might be unreliable. But if we don't know, we delegate
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// to the system.
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ext := filepath.Ext(file)
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switch ext {
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case ".htm", ".html":
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return "text/html"
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case ".css":
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return "text/css"
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case ".js":
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return "application/javascript"
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case ".json":
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return "application/json"
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case ".png":
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return "image/png"
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case ".ttf":
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return "application/x-font-ttf"
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case ".woff":
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return "application/x-font-woff"
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case ".svg":
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return "image/svg+xml"
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default:
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return mime.TypeByExtension(ext)
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}
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}
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func handleRequest(w http.ResponseWriter, r *http.Request) {
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if ipHeader != "" {
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r.RemoteAddr = r.Header.Get(ipHeader)
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}
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w.Header().Set("Access-Control-Allow-Origin", "*")
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switch r.Method {
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case "GET":
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if limit(r.RemoteAddr, getLRUCache, getMut, getLimit, int64(getLimitBurst)) {
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w.WriteHeader(429)
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return
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}
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handleGetRequest(w, r)
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case "POST":
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if limit(r.RemoteAddr, postLRUCache, postMut, postLimit, int64(postLimitBurst)) {
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w.WriteHeader(429)
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return
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}
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handlePostRequest(w, r)
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default:
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if debug {
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log.Println("Unhandled HTTP method", r.Method)
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}
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http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
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}
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}
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func handleGetRequest(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("Content-Type", "application/json; charset=utf-8")
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mut.RLock()
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relays := append(permanentRelays, knownRelays...)
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mut.RUnlock()
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// Shuffle
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for i := range relays {
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j := rand.Intn(i + 1)
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relays[i], relays[j] = relays[j], relays[i]
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}
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json.NewEncoder(w).Encode(map[string][]relay{
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"relays": relays,
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})
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}
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func handlePostRequest(w http.ResponseWriter, r *http.Request) {
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var newRelay relay
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err := json.NewDecoder(r.Body).Decode(&newRelay)
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r.Body.Close()
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if err != nil {
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if debug {
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log.Println("Failed to parse payload")
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}
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http.Error(w, err.Error(), 500)
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return
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}
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uri, err := url.Parse(newRelay.URL)
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if err != nil {
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if debug {
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log.Println("Failed to parse URI", newRelay.URL)
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}
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http.Error(w, err.Error(), 500)
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return
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}
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host, port, err := net.SplitHostPort(uri.Host)
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if err != nil {
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if debug {
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log.Println("Failed to split URI", newRelay.URL)
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}
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http.Error(w, err.Error(), 500)
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return
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}
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// Get the IP address of the client
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rhost, _, err := net.SplitHostPort(r.RemoteAddr)
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if err != nil {
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if debug {
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log.Println("Failed to split remote address", r.RemoteAddr)
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}
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http.Error(w, err.Error(), 500)
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return
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}
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// The client did not provide an IP address, use the IP address of the client.
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if host == "" {
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uri.Host = net.JoinHostPort(rhost, port)
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newRelay.URL = uri.String()
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} else if host != rhost {
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if debug {
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log.Println("IP address advertised does not match client IP address", r.RemoteAddr, uri)
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}
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http.Error(w, "IP address does not match client IP", http.StatusUnauthorized)
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return
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}
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newRelay.uri = uri
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newRelay.Location = getLocation(uri.Host)
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for _, current := range permanentRelays {
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if current.uri.Host == newRelay.uri.Host {
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if debug {
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log.Println("Asked to add a relay", newRelay, "which exists in permanent list")
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}
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http.Error(w, "Invalid request", 500)
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return
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}
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}
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reschan := make(chan result)
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select {
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case requests <- request{newRelay, uri, reschan}:
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result := <-reschan
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if result.err != nil {
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http.Error(w, result.err.Error(), 500)
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return
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}
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w.Header().Set("Content-Type", "application/json; charset=utf-8")
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json.NewEncoder(w).Encode(map[string]time.Duration{
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"evictionIn": result.eviction,
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})
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default:
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if debug {
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log.Println("Dropping request")
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}
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w.WriteHeader(429)
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}
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}
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func requestProcessor() {
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for request := range requests {
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if debug {
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log.Println("Request for", request.relay)
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}
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if !client.TestRelay(request.uri, []tls.Certificate{testCert}, time.Second, 2*time.Second, 3) {
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if debug {
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log.Println("Test for relay", request.relay, "failed")
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}
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request.result <- result{fmt.Errorf("test failed"), 0}
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continue
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}
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mut.Lock()
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timer, ok := evictionTimers[request.relay.uri.Host]
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if ok {
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if debug {
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log.Println("Stopping existing timer for", request.relay)
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}
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timer.Stop()
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}
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for i, current := range knownRelays {
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if current.uri.Host == request.relay.uri.Host {
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if debug {
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log.Println("Relay", request.relay, "already exists")
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}
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// Evict the old entry anyway, as configuration might have changed.
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last := len(knownRelays) - 1
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knownRelays[i] = knownRelays[last]
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knownRelays = knownRelays[:last]
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goto found
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}
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}
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if debug {
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log.Println("Adding new relay", request.relay)
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}
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found:
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knownRelays = append(knownRelays, request.relay)
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evictionTimers[request.relay.uri.Host] = time.AfterFunc(evictionTime, evict(request.relay))
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mut.Unlock()
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request.result <- result{nil, evictionTime}
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}
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}
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func evict(relay relay) func() {
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return func() {
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mut.Lock()
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defer mut.Unlock()
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if debug {
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log.Println("Evicting", relay)
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}
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for i, current := range knownRelays {
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if current.uri.Host == relay.uri.Host {
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if debug {
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log.Println("Evicted", relay)
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}
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last := len(knownRelays) - 1
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knownRelays[i] = knownRelays[last]
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knownRelays = knownRelays[:last]
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}
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}
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delete(evictionTimers, relay.uri.Host)
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}
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}
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func limit(addr string, cache *lru.Cache, lock sync.RWMutex, rate time.Duration, burst int64) bool {
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host, _, err := net.SplitHostPort(addr)
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if err != nil {
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return false
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}
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lock.RLock()
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bkt, ok := cache.Get(host)
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lock.RUnlock()
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if ok {
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bkt := bkt.(*ratelimit.Bucket)
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if bkt.TakeAvailable(1) != 1 {
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// Rate limit
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return true
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}
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} else {
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lock.Lock()
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cache.Add(host, ratelimit.NewBucket(rate, burst))
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lock.Unlock()
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}
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return false
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}
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func loadPermanentRelays(file string) {
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content, err := ioutil.ReadFile(file)
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if err != nil {
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log.Fatal(err)
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}
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for _, line := range strings.Split(string(content), "\n") {
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if len(line) == 0 {
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continue
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}
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uri, err := url.Parse(line)
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if err != nil {
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if debug {
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log.Println("Skipping permanent relay", line, "due to parse error", err)
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}
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continue
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}
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permanentRelays = append(permanentRelays, relay{
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URL: line,
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Location: getLocation(uri.Host),
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uri: uri,
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})
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if debug {
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log.Println("Adding permanent relay", line)
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}
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}
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}
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func createTestCertificate() tls.Certificate {
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tmpDir, err := ioutil.TempDir("", "relaypoolsrv")
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if err != nil {
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log.Fatal(err)
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}
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certFile, keyFile := filepath.Join(tmpDir, "cert.pem"), filepath.Join(tmpDir, "key.pem")
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cert, err := tlsutil.NewCertificate(certFile, keyFile, "relaypoolsrv", 3072)
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if err != nil {
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log.Fatalln("Failed to create test X509 key pair:", err)
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}
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return cert
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}
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func getLocation(host string) location {
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db, err := geoip2.Open(geoipPath)
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if err != nil {
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return location{}
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}
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defer db.Close()
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addr, err := net.ResolveTCPAddr("tcp", host)
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if err != nil {
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return location{}
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}
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city, err := db.City(addr.IP)
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if err != nil {
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return location{}
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}
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return location{
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Latitude: city.Location.Latitude,
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Longitude: city.Location.Longitude,
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}
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}
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