From 4fbb5170d2e46e6a6201e33630e8404796496ef3 Mon Sep 17 00:00:00 2001
From: Sergei Fedosov <s.fedosov@corp.mail.ru>
Date: Fri, 2 Oct 2020 14:41:51 +0300
Subject: [PATCH] tpingd.go: do not use net/http

---
 tpingd.go | 56 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 35 insertions(+), 21 deletions(-)

diff --git a/tpingd.go b/tpingd.go
index 647d5a4..9bd524e 100644
--- a/tpingd.go
+++ b/tpingd.go
@@ -1,11 +1,10 @@
 package main
-// vim: set ft=go noet ai ts=4 sw=4 sts=4:
 
 import (
 	"fmt"
 	"net"
+	"os"
 	"time"
-	"net/http"
 )
 
 var result = false
@@ -25,33 +24,48 @@ func mycheck() {
 	}
 }
 
-// create a handler struct
-type HttpHandler struct{}
+func handleConnection(conn net.Conn) {
+	buf := make([]byte, 1024)
+	bufLen, err := conn.Read(buf)
 
-// implement `ServeHTTP` method on `HttpHandler` struct
-func (h HttpHandler) ServeHTTP(res http.ResponseWriter, req *http.Request) {
-	// create response binary data
-	data := []byte("Unreachable\n") // slice of bytes
+	if err == nil {
+		tail := string(buf[bufLen - 4 : bufLen])
 
-	if result {
-		data = []byte("Reachable\n")
+		// ah, fuck, yea. if you check buffer with \n\r\n\r against "\n\r\n\r" you'll get always FALSE, but if check against hex values, it works
+		if bufLen > 4 && fmt.Sprintf("%x", tail) == "0d0a0d0a" {
+			if result {
+				conn.Write([]byte("HTTP/1.1 200 OK\nContent-Type: text/plain\nConnection: close\n\nReachable\n"))
+			} else {
+				conn.Write([]byte("HTTP/1.1 200 OK\nContent-Type: text/plain\nConnection: close\n\nUnreachable\n"))
+			}
+
+			conn.Close()
+		} else {
+			conn.Write([]byte("HTTP/1.1 400 Bad Request\nContent-Type: text/plain\nConnection: close\n\nBad Request\n"))
+			conn.Close()
+		}
 	}
-
-	// write data to response
-	res.Write(data)
 }
 
-
 func main() {
-	// spawn goroutine, it "backgrounds" automatically
-	go mycheck()
-
-	// create a new handler
-	handler := HttpHandler{}
-	// listen and serve
-	e := http.ListenAndServe("127.0.0.1:9000", handler)
+	ln, e := net.Listen("tcp", "127.0.0.1:9000")
 
 	if e != nil {
 		fmt.Println(e)
+		os.Exit(1)
+	}
+
+	// spawn check goroutine
+	go mycheck()
+
+	for {
+		conn, e := ln.Accept()
+
+		if e != nil {
+			// shit happens, let's try one more time
+			continue
+		}
+
+		go handleConnection(conn)
 	}
 }