hyp/client/main.go

61 lines
1.2 KiB
Go

package main
import (
"fmt"
"log"
"net"
"os"
"time"
"deadbeef.codes/steven/hyp/otphyp"
)
// MaxNetworkLatency specifies the number of milliseconds
// A packet-switched network... more like "race condition factory"
const MaxNetworkLatency = 500
func main() {
// validate number of input arguments
if len(os.Args) < 2 {
usage()
os.Exit(1)
}
// load secret and generate ports using secret and current time
secretBytes, err := os.ReadFile("hyp.secret")
if err != nil {
log.Fatalf("failed to read file 'hyp.secret': %v", err)
}
sharedSecret := string(secretBytes)
ports, err := otphyp.GeneratePorts(sharedSecret, time.Now())
if err != nil {
log.Fatalf("failed to generate ports from shared secret: %v", err)
}
// Transmit
fmt.Println("Transmitting knock sequence:", ports)
for _, port := range ports {
conn, _ := net.Dial("udp", fmt.Sprintf("%s:%d", os.Args[1], port))
conn.Write([]byte{0})
conn.Close()
time.Sleep(time.Millisecond * MaxNetworkLatency)
}
}
func usage() {
fmt.Print(`hyp <server>
Example Usage:
# Transmit an authentic knock sequence to a server
hyp 10.69.4.20
# You can use a DNS name too
hyp hyp.stevenpolley.net
`)
os.Exit(1)
}