From 6f4bd9ad82e5de5bd0dcc3706569d021210b45c6 Mon Sep 17 00:00:00 2001
From: Greg Linton <g2linton@gmail.com>
Date: Tue, 3 Jul 2018 15:58:03 -0600
Subject: [PATCH] Don't read/check msg length

---
 plugins/inputs/syslog/syslog.go | 66 ++++-----------------------------
 1 file changed, 8 insertions(+), 58 deletions(-)

diff --git a/plugins/inputs/syslog/syslog.go b/plugins/inputs/syslog/syslog.go
index daa9b3a46..7d41230e9 100644
--- a/plugins/inputs/syslog/syslog.go
+++ b/plugins/inputs/syslog/syslog.go
@@ -9,7 +9,6 @@ import (
 	"net/url"
 	"os"
 	"strings"
-	"strconv"
 	"sync"
 	"time"
 
@@ -281,46 +280,7 @@ func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
 		conn.Close()
 	}()
 
-	zero := time.Time{}
 	for {
-		tmpLen := make([]byte, 1)
-		length := make([]byte, 0)
-
-		// gather length from beginning of stream
-		for {
-			if s.ReadTimeout != nil && s.ReadTimeout.Duration > 0 {
-				conn.SetReadDeadline(time.Now().Add(s.ReadTimeout.Duration))
-			}
-
-			_, err := conn.Read(tmpLen)
-			if err != nil {
-				// read timeout reached, retry
-				if er, ok := err.(net.Error); ok && er.Timeout() {
-					continue
-				}
-				// client has closed connection, return
-				if err == io.EOF {
-					return
-				}
-				// other error, log and return
-				s.store(rfc5425.Result{Error: fmt.Errorf("failed reading from syslog client - %s", err.Error())}, acc)
-				return
-			}
-
-			// if space found start parsing
-			if tmpLen[0] == byte(32) {
-				break
-			}
-
-			// if byte read is not a number, error
-			if !(tmpLen[0] >= 48 && tmpLen[0] <= 57) {
-				s.store(rfc5425.Result{Error: fmt.Errorf("bad format received")}, acc)
-				return
-			}
-
-			length = append(length, tmpLen[0])
-		}
-
 		data := &bytes.Buffer{}
 
 		// read the data
@@ -332,6 +292,9 @@ func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
 		if err != nil {
 			// read timeout reached, parse what we have
 			if er, ok := err.(net.Error); ok && er.Timeout() {
+				if n == 0 {
+					continue
+				}
 				goto parseMsg
 			}
 			// client has closed connection, return
@@ -345,30 +308,17 @@ func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
 			s.store(rfc5425.Result{Error: fmt.Errorf("failed reading from syslog client - %s", err.Error())}, acc)
 			return
 		}
-
-parseMsg:
-		x, err := strconv.Atoi(string(length))
-		if err != nil {
-			s.store(rfc5425.Result{Error: fmt.Errorf("bad length received - %s", err.Error())}, acc)
+		// handle client disconnect
+		if n == 0 {
 			return
 		}
 
-		if n < int64(x) {
-			s.store(rfc5425.Result{Error: fmt.Errorf("failed reading all of msg; got %d, expected %d", n, x)}, acc)
-			return
-		}
-
-		conn.SetReadDeadline(zero)
-
-		// reconstruct syslog payload for parser
-		length = append(length, byte(32))
-		tdata := append(length, data.Bytes()...)
-
+	parseMsg:
 		var p *rfc5425.Parser
 		if s.BestEffort {
-			p = rfc5425.NewParser(bytes.NewReader(tdata), rfc5425.WithBestEffort())
+			p = rfc5425.NewParser(data, rfc5425.WithBestEffort())
 		} else {
-			p = rfc5425.NewParser(bytes.NewReader(tdata))
+			p = rfc5425.NewParser(data)
 		}
 
 		p.ParseExecuting(func(r *rfc5425.Result) {