initial commit

client/README.md

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+# hyp-client
+
+The client expects there to be a file named hyp.secret in the same directory.  This file is generated by the hypd server using ./hypd generatesecret.  
+
+```bash
+# Example Usage
+# ./hyp-client <server>
+./hyp-client 192.168.50.5
+```

client/go.mod

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+module deadbeef.codes/steven/hyp-client
+
+go 1.22.0
+
+require deadbeef.codes/steven/hyp/otphyp v0.0.0-20240407035202-7ccdf4d89fee

client/go.sum

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+deadbeef.codes/steven/hyp/otphyp v0.0.0-20240407035202-7ccdf4d89fee h1:r9xdoIGPhc/tXzyOj+lCDb+ReYa/zkysqK3ZRCqpyIU=
+deadbeef.codes/steven/hyp/otphyp v0.0.0-20240407035202-7ccdf4d89fee/go.mod h1:NANpGD/K+nDkW+bkomchwaXMrsXWza58+8AR7Sau3fs=

client/main.go

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+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.Println(os.Args[0], "usage")
+	fmt.Println("Supply an ordered list of ports to knock")
+	fmt.Println(os.Args[0], "server")
+}