xs/demo/client/client.go

86 lines
2.2 KiB
Go

package main
import (
"flag"
"fmt"
"io"
"os"
"sync"
hkex "blitter.com/herradurakex"
)
// Demo of a simple client that dials up to a simple test server to
// send data.
//
// While conforming to the basic net.Conn interface HKex.Conn has extra
// capabilities designed to allow apps to define connection options,
// encryption/hmac settings and operations across the encrypted channel.
//
// Initial setup is the same as using plain net.Dial(), but one may
// specify extra extension tags (strings) to set the cipher and hmac
// setting desired; as well as the intended operation mode for the
// connection (app-specific, passed through to the server to use or
// ignore at its discretion).
func main() {
var wg sync.WaitGroup
var cAlg string
var hAlg string
var server string
flag.StringVar(&cAlg, "c", "C_AES_256", "cipher [\"C_AES_256\" | \"C_TWOFISH_128\" | \"C_BLOWFISH_64\"]")
flag.StringVar(&hAlg, "h", "H_SHA256", "hmac [\"H_SHA256\"]")
flag.StringVar(&server, "s", "localhost:2000", "server hostname/address[:port]")
flag.Parse()
conn, err := hkex.Dial("tcp", server, cAlg, hAlg)
if err != nil {
fmt.Println("Err!")
panic(err)
}
defer conn.Close()
wg.Add(1)
go func() {
// This will guarantee the side that closes first
// marks its direction's goroutine as finished.
// Whichever direction's goroutine finishes first
// will call wg.Done() once more explicitly to
// hang up on the other side so the client
// exits immediately on an EOF from either side.
defer wg.Done()
// io.Copy() expects EOF so this will
// exit with inerr == nil
_, inerr := io.Copy(os.Stdout, conn)
if inerr != nil {
if inerr.Error() != "EOF" {
fmt.Println(inerr)
os.Exit(1)
}
}
fmt.Println("[Got Write EOF]")
wg.Done() // client hanging up, close server read goroutine
}()
wg.Add(1)
go func() {
defer wg.Done()
// io.Copy() expects EOF so this will
// exit with outerr == nil
_, outerr := io.Copy(conn, os.Stdin)
if outerr != nil {
if outerr.Error() != "EOF" {
fmt.Println(outerr)
os.Exit(2)
}
}
fmt.Println("[Got Read EOF]")
wg.Done() // server hung up, close client write goroutine
}()
// Wait until both stdin and stdout goroutines finish
wg.Wait()
}