94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
package syslogserver
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import (
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"fmt"
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"net"
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"strings"
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"time"
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log "github.com/sirupsen/logrus"
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"gopkg.in/tomb.v2"
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)
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type SyslogServer struct {
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listenAddr string
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port int
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channel chan SyslogMessage
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udpConn *net.UDPConn
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Logger *log.Entry
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MaxMessageLen int
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}
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type SyslogMessage struct {
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Message []byte
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Client string
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}
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func (s *SyslogServer) Listen(listenAddr string, port int) error {
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s.listenAddr = listenAddr
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s.port = port
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udpAddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", s.listenAddr, s.port))
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if err != nil {
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return fmt.Errorf("could not resolve addr %s: %w", s.listenAddr, err)
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}
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udpConn, err := net.ListenUDP("udp", udpAddr)
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if err != nil {
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return fmt.Errorf("could not listen on port %d: %w", s.port, err)
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}
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s.Logger.Debugf("listening on %s:%d", s.listenAddr, s.port)
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s.udpConn = udpConn
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err = s.udpConn.SetReadDeadline(time.Now().UTC().Add(100 * time.Millisecond))
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if err != nil {
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return fmt.Errorf("could not set read deadline on UDP socket: %w", err)
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}
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return nil
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}
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func (s *SyslogServer) SetChannel(c chan SyslogMessage) {
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s.channel = c
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}
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func (s *SyslogServer) StartServer() *tomb.Tomb {
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t := tomb.Tomb{}
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t.Go(func() error {
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for {
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select {
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case <-t.Dying():
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s.Logger.Info("Syslog server tomb is dying")
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err := s.KillServer()
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return err
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default:
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//RFC3164 says 1024 bytes max
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//RFC5424 says 480 bytes minimum, and should support up to 2048 bytes
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b := make([]byte, s.MaxMessageLen)
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n, addr, err := s.udpConn.ReadFrom(b)
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if err != nil && !strings.Contains(err.Error(), "i/o timeout") {
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s.Logger.Errorf("error while reading from socket : %s", err)
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s.udpConn.Close()
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return err
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}
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if err == nil {
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s.channel <- SyslogMessage{Message: b[:n], Client: strings.Split(addr.String(), ":")[0]}
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}
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err = s.udpConn.SetReadDeadline(time.Now().UTC().Add(100 * time.Millisecond))
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if err != nil {
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return err
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}
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}
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}
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})
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return &t
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}
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func (s *SyslogServer) KillServer() error {
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err := s.udpConn.Close()
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if err != nil {
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return fmt.Errorf("could not close UDP connection: %w", err)
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}
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close(s.channel)
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return nil
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}
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