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package main
import (
"flag"
"fmt"
"io"
"net"
)
func main() {
target := flag.String("target", "", "the server address")
payload := flag.String("message", "", "the message to send to the server")
protocol := flag.String("protocol", "tcp", "the protocol to use with the server [udp,tcp], default tcp")
flag.Parse()
if *target == "" || *payload == "" {
flag.Usage()
panic("invalid arguments")
}
switch *protocol {
case "tcp":
connectTCP(*target, *payload)
case "udp":
connectUDP(*target, *payload)
default:
panic("invalid protocol")
}
}
func connectTCP(target, payload string) {
conn, err := net.Dial("tcp", target)
if err != nil {
panic(fmt.Sprintf("Failed to open connection to [%s] %v", target, err))
}
defer conn.Close()
_, err = conn.Write([]byte(payload))
if err != nil {
panic("Failed to send payload")
}
_, err = conn.Write([]byte("\n"))
if err != nil {
panic("Failed to send payload")
}
buf := make([]byte, 1024)
for {
n, err := conn.Read(buf)
fmt.Print(string(buf[:n]))
if err == io.EOF {
break
}
if err != nil {
panic("Failed to read from socket")
}
}
}
// UDP uses a constant source port to trigger conntrack problems
func connectUDP(target, payload string) {
LocalAddr, err := net.ResolveUDPAddr("udp", ":54321")
if err != nil {
panic(fmt.Sprintf("Failed to resolve UDP local address on port 54321 %v", err))
}
RemoteAddr, err := net.ResolveUDPAddr("udp", target)
if err != nil {
panic(fmt.Sprintf("Failed to resolve UDP remote address [%s] %v", target, err))
}
conn, err := net.DialUDP("udp", LocalAddr, RemoteAddr)
if err != nil {
panic(fmt.Sprintf("Failed to open connection to [%s] %v", target, err))
}
defer conn.Close()
_, err = conn.Write([]byte(payload))
if err != nil {
panic("Failed to send payload")
}
_, err = conn.Write([]byte("\n"))
if err != nil {
panic("Failed to send payload")
}
buf := make([]byte, 1024)
n, err := conn.Read(buf)
if err != nil {
panic("Failed to read from socket")
}
fmt.Print(string(buf[:n]))
}
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