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|
package main
import (
"fmt"
"io"
"log"
"net"
"os"
"strconv"
"sync"
"syscall"
"time"
)
func usage() {
fmt.Fprintf(os.Stderr,
"Usage: porter action host min max\n\n"+
"-- action is any of dial, listen\n"+
"-- min, max is tcp port values\n",
)
os.Exit(2)
}
func parsePositive(s string) int {
n, err := strconv.Atoi(s)
if err != nil || n <= 0 {
return -1
}
return n
}
func setlimit(total int) {
nfds := uint64(total)
rlim := syscall.Rlimit{}
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlim); err != nil {
log.Fatal(err)
}
if nfds > rlim.Max {
log.Fatalf("too big port range %d, max %d", nfds, rlim.Max)
}
if nfds > rlim.Cur {
rlim.Cur = nfds
if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlim); err != nil {
log.Fatal(err)
}
}
}
func dial(host string, min, max int) {
var wg sync.WaitGroup
setlimit((max - min + 1) + 32)
tout := time.Second
for n := min; n <= max; n++ {
wg.Add(1)
go func(port int) {
defer wg.Done()
c, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", host, port), tout)
if err != nil {
fmt.Printf("fail %d dial: %s\n", port, err)
return
}
fmt.Printf("ok %d dial\n", port)
fmt.Fprint(c, "test")
c.Close()
}(n)
}
wg.Wait()
}
func listen(host string, min, max int) {
ready := make(chan struct{})
setlimit(2*(max-min+1) + 32)
for n := min; n <= max; n++ {
l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", host, n))
if err != nil {
log.Fatal(err)
}
go func(l net.Listener, port int) {
<-ready
for {
c, err := l.Accept()
if err != nil {
fmt.Printf("fail %d accept: %s\n", port, err)
continue
}
fmt.Printf("ok %d accept\n", port)
buf := make([]byte, 1024)
for {
n, err := c.Read(buf)
if err != nil {
if err == io.EOF {
fmt.Printf("ok %d close\n", port)
} else {
fmt.Printf("fail %d read: %s\n", port, err)
}
break
}
fmt.Printf("ok %d read %d bytes\n", port, n)
}
c.Close()
}
}(l, n)
}
close(ready)
syscall.Pause()
}
func main() {
log.SetFlags(0)
if len(os.Args) < 5 {
usage()
}
action := os.Args[1]
host := os.Args[2]
min := parsePositive(os.Args[3])
max := parsePositive(os.Args[4])
if min < 0 || max < 0 || min > max {
usage()
}
switch action {
case "dial":
dial(host, min, max)
case "listen":
listen(host, min, max)
default:
usage()
}
}
|
