syncthing/cmd/relaysrv/main.go
2015-11-21 00:35:38 +00:00

204 lines
6.6 KiB
Go

// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
package main
import (
"crypto/tls"
"flag"
"fmt"
"log"
"net"
"net/url"
"os"
"os/signal"
"path/filepath"
"runtime"
"strings"
"sync/atomic"
"syscall"
"time"
"github.com/juju/ratelimit"
"github.com/syncthing/syncthing/lib/osutil"
"github.com/syncthing/syncthing/lib/relay/protocol"
"github.com/syncthing/syncthing/lib/tlsutil"
syncthingprotocol "github.com/syncthing/syncthing/lib/protocol"
)
var (
listen string
debug bool = false
sessionAddress []byte
sessionPort uint16
networkTimeout time.Duration = 2 * time.Minute
pingInterval time.Duration = time.Minute
messageTimeout time.Duration = time.Minute
limitCheckTimer *time.Timer
sessionLimitBps int
globalLimitBps int
overLimit int32
descriptorLimit int64
sessionLimiter *ratelimit.Bucket
globalLimiter *ratelimit.Bucket
statusAddr string
poolAddrs string
pools []string
providedBy string
defaultPoolAddrs string = "https://relays.syncthing.net/endpoint"
)
func main() {
log.SetFlags(log.Lshortfile | log.LstdFlags)
var dir, extAddress string
flag.StringVar(&listen, "listen", ":22067", "Protocol listen address")
flag.StringVar(&dir, "keys", ".", "Directory where cert.pem and key.pem is stored")
flag.DurationVar(&networkTimeout, "network-timeout", networkTimeout, "Timeout for network operations between the client and the relay.\n\tIf no data is received between the client and the relay in this period of time, the connection is terminated.\n\tFurthermore, if no data is sent between either clients being relayed within this period of time, the session is also terminated.")
flag.DurationVar(&pingInterval, "ping-interval", pingInterval, "How often pings are sent")
flag.DurationVar(&messageTimeout, "message-timeout", messageTimeout, "Maximum amount of time we wait for relevant messages to arrive")
flag.IntVar(&sessionLimitBps, "per-session-rate", sessionLimitBps, "Per session rate limit, in bytes/s")
flag.IntVar(&globalLimitBps, "global-rate", globalLimitBps, "Global rate limit, in bytes/s")
flag.BoolVar(&debug, "debug", debug, "Enable debug output")
flag.StringVar(&statusAddr, "status-srv", ":22070", "Listen address for status service (blank to disable)")
flag.StringVar(&poolAddrs, "pools", defaultPoolAddrs, "Comma separated list of relay pool addresses to join")
flag.StringVar(&providedBy, "provided-by", "", "An optional description about who provides the relay")
flag.StringVar(&extAddress, "ext-address", "", "An optional address to advertising as being available on.\n\tAllows listening on an unprivileged port with port forwarding from e.g. 443, and be connected to on port 443.")
flag.Parse()
if extAddress == "" {
extAddress = listen
}
addr, err := net.ResolveTCPAddr("tcp", extAddress)
if err != nil {
log.Fatal(err)
}
maxDescriptors, err := osutil.MaximizeOpenFileLimit()
if maxDescriptors > 0 {
// Assume that 20% of FD's are leaked/unaccounted for.
descriptorLimit = int64(maxDescriptors*80) / 100
log.Println("Connection limit", descriptorLimit)
go monitorLimits()
} else if err != nil && runtime.GOOS != "windows" {
log.Println("Assuming no connection limit, due to error retrievign rlimits:", err)
}
sessionAddress = addr.IP[:]
sessionPort = uint16(addr.Port)
certFile, keyFile := filepath.Join(dir, "cert.pem"), filepath.Join(dir, "key.pem")
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
log.Println("Failed to load keypair. Generating one, this might take a while...")
cert, err = tlsutil.NewCertificate(certFile, keyFile, "relaysrv", 3072)
if err != nil {
log.Fatalln("Failed to generate X509 key pair:", err)
}
}
tlsCfg := &tls.Config{
Certificates: []tls.Certificate{cert},
NextProtos: []string{protocol.ProtocolName},
ClientAuth: tls.RequestClientCert,
SessionTicketsDisabled: true,
InsecureSkipVerify: true,
MinVersion: tls.VersionTLS12,
CipherSuites: []uint16{
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,
},
}
id := syncthingprotocol.NewDeviceID(cert.Certificate[0])
if debug {
log.Println("ID:", id)
}
if sessionLimitBps > 0 {
sessionLimiter = ratelimit.NewBucketWithRate(float64(sessionLimitBps), int64(2*sessionLimitBps))
}
if globalLimitBps > 0 {
globalLimiter = ratelimit.NewBucketWithRate(float64(globalLimitBps), int64(2*globalLimitBps))
}
if statusAddr != "" {
go statusService(statusAddr)
}
uri, err := url.Parse(fmt.Sprintf("relay://%s/?id=%s&pingInterval=%s&networkTimeout=%s&sessionLimitBps=%d&globalLimitBps=%d&statusAddr=%s&providedBy=%s", extAddress, id, pingInterval, networkTimeout, sessionLimitBps, globalLimitBps, statusAddr, providedBy))
if err != nil {
log.Fatalln("Failed to construct URI", err)
}
log.Println("URI:", uri.String())
if poolAddrs == defaultPoolAddrs {
log.Println("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
log.Println("!! Joining default relay pools, this relay will be available for public use. !!")
log.Println(`!! Use the -pools="" command line option to make the relay private. !!`)
log.Println("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
}
pools = strings.Split(poolAddrs, ",")
for _, pool := range pools {
pool = strings.TrimSpace(pool)
if len(pool) > 0 {
go poolHandler(pool, uri)
}
}
go listener(listen, tlsCfg)
sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
<-sigs
// Gracefully close all connections, hoping that clients will be faster
// to realize that the relay is now gone.
sessionMut.RLock()
for _, session := range activeSessions {
session.CloseConns()
}
for _, session := range pendingSessions {
session.CloseConns()
}
sessionMut.RUnlock()
outboxesMut.RLock()
for _, outbox := range outboxes {
close(outbox)
}
outboxesMut.RUnlock()
time.Sleep(500 * time.Millisecond)
}
func monitorLimits() {
limitCheckTimer = time.NewTimer(time.Minute)
for range limitCheckTimer.C {
if atomic.LoadInt64(&numConnections)+atomic.LoadInt64(&numProxies) > descriptorLimit {
atomic.StoreInt32(&overLimit, 1)
log.Println("Gone past our connection limits. Starting to refuse new/drop idle connections.")
} else if atomic.CompareAndSwapInt32(&overLimit, 1, 0) {
log.Println("Dropped below our connection limits. Accepting new connections.")
}
limitCheckTimer.Reset(time.Minute)
}
}