package main import ( "flag" "fmt" "io" "io/ioutil" "log" "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() log.SetOutput(ioutil.Discard) 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() }