Enhance syslog reading and ensure proper length is read

This commit is contained in:
Greg Linton 2018-07-03 15:05:59 -06:00
parent a7545e6cac
commit 4ea618ea26
1 changed files with 58 additions and 14 deletions

View File

@ -9,6 +9,7 @@ import (
"net/url"
"os"
"strings"
"strconv"
"sync"
"time"
@ -282,19 +283,16 @@ func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
zero := time.Time{}
for {
// make a temporary bytes var to read from the connection
tmp := make([]byte, 128)
// make 0 length data bytes (since we'll be appending)
data := make([]byte, 0)
tmpLen := make([]byte, 1)
length := make([]byte, 0)
// loop through the connection stream, appending tmp to data
// gather length from beginning of stream
for {
if s.ReadTimeout != nil && s.ReadTimeout.Duration > 0 {
conn.SetReadDeadline(time.Now().Add(s.ReadTimeout.Duration))
}
// read to the tmp var
n, err := conn.Read(tmp)
_, err := conn.Read(tmpLen)
if err != nil {
// read timeout reached, retry
if er, ok := err.(net.Error); ok && er.Timeout() {
@ -309,22 +307,68 @@ func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
return
}
// append read data to full data
data = append(data, tmp[:n]...)
// break if ends with '\n' (todo: need to ensure writing w/o "\n" works)
if tmp[n-1] == '\n' { //|| tmp[n-1] == 'EOF' {
// 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
if s.ReadTimeout != nil && s.ReadTimeout.Duration > 0 {
conn.SetReadDeadline(time.Now().Add(s.ReadTimeout.Duration))
}
n, err := io.Copy(data, conn)
if err != nil {
// read timeout reached, parse what we have
if er, ok := err.(net.Error); ok && er.Timeout() {
goto parseMsg
}
// client has closed connection, return
if err == io.EOF {
if n > 0 {
goto parseMsg
}
return
}
// other error, log and return
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)
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()...)
var p *rfc5425.Parser
if s.BestEffort {
p = rfc5425.NewParser(bytes.NewReader(data), rfc5425.WithBestEffort())
p = rfc5425.NewParser(bytes.NewReader(tdata), rfc5425.WithBestEffort())
} else {
p = rfc5425.NewParser(bytes.NewReader(data))
p = rfc5425.NewParser(bytes.NewReader(tdata))
}
p.ParseExecuting(func(r *rfc5425.Result) {