syncthing/cmd/strelaypoolsrv/main.go
2016-12-21 14:53:45 +01:00

540 lines
13 KiB
Go

// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
//go:generate go run ../../script/genassets.go gui >auto/gui.go
package main
import (
"bytes"
"compress/gzip"
"crypto/tls"
"encoding/json"
"flag"
"fmt"
"io/ioutil"
"log"
"math/rand"
"mime"
"net"
"net/http"
"net/url"
"path/filepath"
"strings"
"time"
"github.com/golang/groupcache/lru"
"github.com/juju/ratelimit"
"github.com/oschwald/geoip2-golang"
"github.com/syncthing/syncthing/cmd/strelaypoolsrv/auto"
"github.com/syncthing/syncthing/lib/relay/client"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/tlsutil"
)
type location struct {
Latitude float64 `json:"latitude"`
Longitude float64 `json:"longitude"`
}
type relay struct {
URL string `json:"url"`
Location location `json:"location"`
uri *url.URL
}
func (r relay) String() string {
return r.URL
}
type request struct {
relay relay
uri *url.URL
result chan result
}
type result struct {
err error
eviction time.Duration
}
var (
testCert tls.Certificate
listen = ":80"
dir string
evictionTime = time.Hour
debug bool
getLRUSize = 10 << 10
getLimitBurst int64 = 10
getLimitAvg = 1
postLRUSize = 1 << 10
postLimitBurst int64 = 2
postLimitAvg = 1
getLimit time.Duration
postLimit time.Duration
permRelaysFile string
ipHeader string
geoipPath string
proto string
getMut = sync.NewRWMutex()
getLRUCache *lru.Cache
postMut = sync.NewRWMutex()
postLRUCache *lru.Cache
requests = make(chan request, 10)
mut = sync.NewRWMutex()
knownRelays = make([]relay, 0)
permanentRelays = make([]relay, 0)
evictionTimers = make(map[string]*time.Timer)
)
func main() {
flag.StringVar(&listen, "listen", listen, "Listen address")
flag.StringVar(&dir, "keys", dir, "Directory where http-cert.pem and http-key.pem is stored for TLS listening")
flag.BoolVar(&debug, "debug", debug, "Enable debug output")
flag.DurationVar(&evictionTime, "eviction", evictionTime, "After how long the relay is evicted")
flag.IntVar(&getLRUSize, "get-limit-cache", getLRUSize, "Get request limiter cache size")
flag.IntVar(&getLimitAvg, "get-limit-avg", 2, "Allowed average get request rate, per 10 s")
flag.Int64Var(&getLimitBurst, "get-limit-burst", getLimitBurst, "Allowed burst get requests")
flag.IntVar(&postLRUSize, "post-limit-cache", postLRUSize, "Post request limiter cache size")
flag.IntVar(&postLimitAvg, "post-limit-avg", 2, "Allowed average post request rate, per minute")
flag.Int64Var(&postLimitBurst, "post-limit-burst", postLimitBurst, "Allowed burst post requests")
flag.StringVar(&permRelaysFile, "perm-relays", "", "Path to list of permanent relays")
flag.StringVar(&ipHeader, "ip-header", "", "Name of header which holds clients ip:port. Only meaningful when running behind a reverse proxy.")
flag.StringVar(&geoipPath, "geoip", "GeoLite2-City.mmdb", "Path to GeoLite2-City database")
flag.StringVar(&proto, "protocol", "tcp", "Protocol used for listening. 'tcp' for IPv4 and IPv6, 'tcp4' for IPv4, 'tcp6' for IPv6")
flag.Parse()
getLimit = 10 * time.Second / time.Duration(getLimitAvg)
postLimit = time.Minute / time.Duration(postLimitAvg)
getLRUCache = lru.New(getLRUSize)
postLRUCache = lru.New(postLRUSize)
var listener net.Listener
var err error
if permRelaysFile != "" {
loadPermanentRelays(permRelaysFile)
}
testCert = createTestCertificate()
go requestProcessor()
if dir != "" {
if debug {
log.Println("Starting TLS listener on", listen)
}
certFile, keyFile := filepath.Join(dir, "http-cert.pem"), filepath.Join(dir, "http-key.pem")
var cert tls.Certificate
cert, err = tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
log.Fatalln("Failed to load HTTP X509 key pair:", err)
}
tlsCfg := &tls.Config{
Certificates: []tls.Certificate{cert},
MinVersion: tls.VersionTLS10, // No SSLv3
CipherSuites: []uint16{
// No RC4
tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
tls.TLS_RSA_WITH_AES_128_CBC_SHA,
tls.TLS_RSA_WITH_AES_256_CBC_SHA,
tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
},
}
listener, err = tls.Listen(proto, listen, tlsCfg)
} else {
if debug {
log.Println("Starting plain listener on", listen)
}
listener, err = net.Listen(proto, listen)
}
if err != nil {
log.Fatalln("listen:", err)
}
handler := http.NewServeMux()
handler.HandleFunc("/", handleAssets)
handler.HandleFunc("/endpoint", handleRequest)
srv := http.Server{
Handler: handler,
ReadTimeout: 10 * time.Second,
}
err = srv.Serve(listener)
if err != nil {
log.Fatalln("serve:", err)
}
}
func handleAssets(w http.ResponseWriter, r *http.Request) {
assets := auto.Assets()
path := r.URL.Path[1:]
if path == "" {
path = "index.html"
}
bs, ok := assets[path]
if !ok {
w.WriteHeader(http.StatusNotFound)
return
}
mtype := mimeTypeForFile(path)
if len(mtype) != 0 {
w.Header().Set("Content-Type", mtype)
}
if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
w.Header().Set("Content-Encoding", "gzip")
} else {
// ungzip if browser not send gzip accepted header
var gr *gzip.Reader
gr, _ = gzip.NewReader(bytes.NewReader(bs))
bs, _ = ioutil.ReadAll(gr)
gr.Close()
}
w.Header().Set("Content-Length", fmt.Sprintf("%d", len(bs)))
w.Write(bs)
}
func mimeTypeForFile(file string) string {
// We use a built in table of the common types since the system
// TypeByExtension might be unreliable. But if we don't know, we delegate
// to the system.
ext := filepath.Ext(file)
switch ext {
case ".htm", ".html":
return "text/html"
case ".css":
return "text/css"
case ".js":
return "application/javascript"
case ".json":
return "application/json"
case ".png":
return "image/png"
case ".ttf":
return "application/x-font-ttf"
case ".woff":
return "application/x-font-woff"
case ".svg":
return "image/svg+xml"
default:
return mime.TypeByExtension(ext)
}
}
func handleRequest(w http.ResponseWriter, r *http.Request) {
if ipHeader != "" {
r.RemoteAddr = r.Header.Get(ipHeader)
}
w.Header().Set("Access-Control-Allow-Origin", "*")
switch r.Method {
case "GET":
if limit(r.RemoteAddr, getLRUCache, getMut, getLimit, getLimitBurst) {
w.WriteHeader(429)
return
}
handleGetRequest(w, r)
case "POST":
if limit(r.RemoteAddr, postLRUCache, postMut, postLimit, postLimitBurst) {
w.WriteHeader(429)
return
}
handlePostRequest(w, r)
default:
if debug {
log.Println("Unhandled HTTP method", r.Method)
}
http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
}
}
func handleGetRequest(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json; charset=utf-8")
mut.RLock()
relays := append(permanentRelays, knownRelays...)
mut.RUnlock()
// Shuffle
for i := range relays {
j := rand.Intn(i + 1)
relays[i], relays[j] = relays[j], relays[i]
}
json.NewEncoder(w).Encode(map[string][]relay{
"relays": relays,
})
}
func handlePostRequest(w http.ResponseWriter, r *http.Request) {
var newRelay relay
err := json.NewDecoder(r.Body).Decode(&newRelay)
r.Body.Close()
if err != nil {
if debug {
log.Println("Failed to parse payload")
}
http.Error(w, err.Error(), 500)
return
}
uri, err := url.Parse(newRelay.URL)
if err != nil {
if debug {
log.Println("Failed to parse URI", newRelay.URL)
}
http.Error(w, err.Error(), 500)
return
}
host, port, err := net.SplitHostPort(uri.Host)
if err != nil {
if debug {
log.Println("Failed to split URI", newRelay.URL)
}
http.Error(w, err.Error(), 500)
return
}
// Get the IP address of the client
rhost, _, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
if debug {
log.Println("Failed to split remote address", r.RemoteAddr)
}
http.Error(w, err.Error(), 500)
return
}
ip := net.ParseIP(host)
// The client did not provide an IP address, use the IP address of the client.
if ip == nil || ip.IsUnspecified() {
uri.Host = net.JoinHostPort(rhost, port)
newRelay.URL = uri.String()
} else if host != rhost {
if debug {
log.Println("IP address advertised does not match client IP address", r.RemoteAddr, uri)
}
http.Error(w, "IP address does not match client IP", http.StatusUnauthorized)
return
}
newRelay.uri = uri
newRelay.Location = getLocation(uri.Host)
for _, current := range permanentRelays {
if current.uri.Host == newRelay.uri.Host {
if debug {
log.Println("Asked to add a relay", newRelay, "which exists in permanent list")
}
http.Error(w, "Invalid request", 500)
return
}
}
reschan := make(chan result)
select {
case requests <- request{newRelay, uri, reschan}:
result := <-reschan
if result.err != nil {
http.Error(w, result.err.Error(), 500)
return
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
json.NewEncoder(w).Encode(map[string]time.Duration{
"evictionIn": result.eviction,
})
default:
if debug {
log.Println("Dropping request")
}
w.WriteHeader(429)
}
}
func requestProcessor() {
for request := range requests {
if debug {
log.Println("Request for", request.relay)
}
if !client.TestRelay(request.uri, []tls.Certificate{testCert}, time.Second, 2*time.Second, 3) {
if debug {
log.Println("Test for relay", request.relay, "failed")
}
request.result <- result{fmt.Errorf("test failed"), 0}
continue
}
mut.Lock()
timer, ok := evictionTimers[request.relay.uri.Host]
if ok {
if debug {
log.Println("Stopping existing timer for", request.relay)
}
timer.Stop()
}
for i, current := range knownRelays {
if current.uri.Host == request.relay.uri.Host {
if debug {
log.Println("Relay", request.relay, "already exists")
}
// Evict the old entry anyway, as configuration might have changed.
last := len(knownRelays) - 1
knownRelays[i] = knownRelays[last]
knownRelays = knownRelays[:last]
goto found
}
}
if debug {
log.Println("Adding new relay", request.relay)
}
found:
knownRelays = append(knownRelays, request.relay)
evictionTimers[request.relay.uri.Host] = time.AfterFunc(evictionTime, evict(request.relay))
mut.Unlock()
request.result <- result{nil, evictionTime}
}
}
func evict(relay relay) func() {
return func() {
mut.Lock()
defer mut.Unlock()
if debug {
log.Println("Evicting", relay)
}
for i, current := range knownRelays {
if current.uri.Host == relay.uri.Host {
if debug {
log.Println("Evicted", relay)
}
last := len(knownRelays) - 1
knownRelays[i] = knownRelays[last]
knownRelays = knownRelays[:last]
}
}
delete(evictionTimers, relay.uri.Host)
}
}
func limit(addr string, cache *lru.Cache, lock sync.RWMutex, rate time.Duration, burst int64) bool {
host, _, err := net.SplitHostPort(addr)
if err != nil {
return false
}
lock.RLock()
bkt, ok := cache.Get(host)
lock.RUnlock()
if ok {
bkt := bkt.(*ratelimit.Bucket)
if bkt.TakeAvailable(1) != 1 {
// Rate limit
return true
}
} else {
lock.Lock()
cache.Add(host, ratelimit.NewBucket(rate, burst))
lock.Unlock()
}
return false
}
func loadPermanentRelays(file string) {
content, err := ioutil.ReadFile(file)
if err != nil {
log.Fatal(err)
}
for _, line := range strings.Split(string(content), "\n") {
if len(line) == 0 {
continue
}
uri, err := url.Parse(line)
if err != nil {
if debug {
log.Println("Skipping permanent relay", line, "due to parse error", err)
}
continue
}
permanentRelays = append(permanentRelays, relay{
URL: line,
Location: getLocation(uri.Host),
uri: uri,
})
if debug {
log.Println("Adding permanent relay", line)
}
}
}
func createTestCertificate() tls.Certificate {
tmpDir, err := ioutil.TempDir("", "relaypoolsrv")
if err != nil {
log.Fatal(err)
}
certFile, keyFile := filepath.Join(tmpDir, "cert.pem"), filepath.Join(tmpDir, "key.pem")
cert, err := tlsutil.NewCertificate(certFile, keyFile, "relaypoolsrv", 3072)
if err != nil {
log.Fatalln("Failed to create test X509 key pair:", err)
}
return cert
}
func getLocation(host string) location {
db, err := geoip2.Open(geoipPath)
if err != nil {
return location{}
}
defer db.Close()
addr, err := net.ResolveTCPAddr("tcp", host)
if err != nil {
return location{}
}
city, err := db.City(addr.IP)
if err != nil {
return location{}
}
return location{
Latitude: city.Location.Latitude,
Longitude: city.Location.Longitude,
}
}