forked from xjdrew/gopf
/
gopf.go
270 lines (225 loc) · 5.37 KB
/
gopf.go
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//
// date : 2014-05-23 17:35
// author: xjdrew
//
package main
import(
"log"
"log/syslog"
"fmt"
"flag"
"time"
"os"
"os/signal"
"syscall"
"encoding/json"
"math/rand"
"net"
"sync"
"sync/atomic"
)
func usage() {
fmt.Fprintf(os.Stderr, "usage: %s [config]\n", os.Args[0])
flag.PrintDefaults()
os.Exit(1)
}
type Host struct {
Addr string
Weight int
addr *net.TCPAddr
}
type Settings struct {
Hosts []Host
weight int
}
type Status struct {
actives int32
}
type PF struct {
// host list
config_file string
settings *Settings
// listen port
localAddr string
// listen port
ln *net.TCPListener
wg sync.WaitGroup
status Status
}
var pf PF
var logger *log.Logger
func readSettings(config_file string) *Settings {
fp, err := os.Open(config_file)
if err != nil {
logger.Printf("open config file failed:%s", err.Error())
return nil
}
defer fp.Close()
var settings Settings
dec := json.NewDecoder(fp)
err = dec.Decode(&settings)
if err != nil {
logger.Printf("decode config file failed:%s", err.Error())
return nil
}
for i := range settings.Hosts {
host := &settings.Hosts[i]
host.addr, err = net.ResolveTCPAddr("tcp", host.Addr)
if err != nil {
logger.Printf("resolve local addr failed:%s", err.Error())
return nil
}
settings.weight += host.Weight
}
logger.Printf("config:%v", settings)
return &settings
}
func chooseHost(weight int, hosts []Host) *Host {
if weight <= 0 {
return nil
}
v := rand.Intn(weight)
for _, host := range(hosts) {
if host.Weight >= v {
return &host
}
v -= host.Weight
}
return nil
}
func forward(source *net.TCPConn, dest *net.TCPConn) {
defer func() {
dest.Close()
}()
bufsz := 1 << 12
cache := make([]byte, bufsz)
for {
// pump from source
n, err1 := source.Read(cache)
// pour into dest
c := 0
var err2 error
for c < n {
i, err2 := dest.Write(cache[c:n])
if err2 != nil {
break
}
c += i
}
if err1 != nil || err2 != nil {
break
}
}
}
func handleClient(pf* PF, source *net.TCPConn) {
atomic.AddInt32(&pf.status.actives, 1)
defer func() {
atomic.AddInt32(&pf.status.actives, -1)
pf.wg.Done()
}()
settings := pf.settings
host := chooseHost(settings.weight, settings.Hosts)
if host == nil {
source.Close()
logger.Println("choose host failed")
return
}
dest,err := net.DialTCP("tcp", nil, host.addr)
if err != nil {
source.Close()
logger.Printf("connect to %s failed: %s", host.addr, err.Error())
return
}
source.SetKeepAlive(true)
source.SetKeepAlivePeriod(time.Second * 60)
source.SetLinger(-1)
dest.SetLinger(-1)
go forward(source, dest)
forward(dest, source)
//logger.Printf("forward finished, %v -> %v", source.RemoteAddr(), host)
}
func start(pf *PF) {
pf.wg.Add(1)
defer func() {
pf.wg.Done()
}()
laddr, err := net.ResolveTCPAddr("tcp", pf.localAddr)
if err != nil {
logger.Printf("resolve local addr failed:%s", err.Error())
return
}
ln, err := net.ListenTCP("tcp", laddr)
if err != nil {
logger.Printf("build listener failed:%s", err.Error())
return
}
pf.ln = ln
for {
conn, err := pf.ln.AcceptTCP()
if err != nil {
logger.Printf("accept failed:%s", err.Error())
break
}
pf.wg.Add(1)
go handleClient(pf, conn)
}
}
const SIG_RELOAD = syscall.Signal(34)
const SIG_STATUS = syscall.Signal(35)
func reload() {
settings := readSettings(pf.config_file)
if settings == nil {
logger.Println("reload failed")
return
}
pf.settings = settings
logger.Println("reload succeed")
}
func status() {
logger.Printf("status: actives-> %d", pf.status.actives)
}
func handleSignal() {
c := make(chan os.Signal, 1)
signal.Notify(c, SIG_RELOAD, SIG_STATUS, syscall.SIGTERM)
for sig := range(c) {
switch sig {
case SIG_RELOAD:
reload()
case SIG_STATUS:
status()
case syscall.SIGTERM:
logger.Println("catch sigterm, ignore")
}
}
}
func init() {
var err error
logger, err = syslog.NewLogger(syslog.LOG_LOCAL0, 0)
if err != nil {
fmt.Printf("create logger failed:%s", err.Error())
os.Exit(1)
}
logger.Println("are you lucky? go!")
rand.Seed(time.Now().Unix())
}
func main() {
flag.StringVar(&pf.localAddr, "listen_addr", "0.0.0.0:1248", "local listen port(0.0.0.0:1248)")
flag.Usage = usage
flag.Parse()
args := flag.Args()
if len(args) < 1 {
logger.Println("config file is missing.")
os.Exit(1)
}
pf.config_file = args[0]
logger.Printf("config file is: %s", pf.config_file)
pf.settings = readSettings(pf.config_file)
if pf.settings == nil {
logger.Println("parse config failed")
os.Exit(1)
}
go handleSignal()
// run
start(&pf)
pf.wg.Wait()
}