gotosocial/vendor/gopkg.in/mcuadros/go-syslog.v2/server.go
tobi c111b239f7
Add optional syslog logrus hook (#343)
* add optional syslog logrus hook

* document syslog
2021-12-12 18:00:20 +01:00

378 lines
8.4 KiB
Go

package syslog
import (
"bufio"
"crypto/tls"
"errors"
"net"
"strings"
"sync"
"time"
"gopkg.in/mcuadros/go-syslog.v2/format"
)
var (
RFC3164 = &format.RFC3164{} // RFC3164: http://www.ietf.org/rfc/rfc3164.txt
RFC5424 = &format.RFC5424{} // RFC5424: http://www.ietf.org/rfc/rfc5424.txt
RFC6587 = &format.RFC6587{} // RFC6587: http://www.ietf.org/rfc/rfc6587.txt - octet counting variant
Automatic = &format.Automatic{} // Automatically identify the format
)
const (
datagramChannelBufferSize = 10
datagramReadBufferSize = 64 * 1024
)
// A function type which gets the TLS peer name from the connection. Can return
// ok=false to terminate the connection
type TlsPeerNameFunc func(tlsConn *tls.Conn) (tlsPeer string, ok bool)
type Server struct {
listeners []net.Listener
connections []net.PacketConn
wait sync.WaitGroup
doneTcp chan bool
datagramChannel chan DatagramMessage
format format.Format
handler Handler
lastError error
readTimeoutMilliseconds int64
tlsPeerNameFunc TlsPeerNameFunc
datagramPool sync.Pool
}
//NewServer returns a new Server
func NewServer() *Server {
return &Server{tlsPeerNameFunc: defaultTlsPeerName, datagramPool: sync.Pool{
New: func() interface{} {
return make([]byte, 65536)
},
}}
}
//Sets the syslog format (RFC3164 or RFC5424 or RFC6587)
func (s *Server) SetFormat(f format.Format) {
s.format = f
}
//Sets the handler, this handler with receive every syslog entry
func (s *Server) SetHandler(handler Handler) {
s.handler = handler
}
//Sets the connection timeout for TCP connections, in milliseconds
func (s *Server) SetTimeout(millseconds int64) {
s.readTimeoutMilliseconds = millseconds
}
// Set the function that extracts a TLS peer name from the TLS connection
func (s *Server) SetTlsPeerNameFunc(tlsPeerNameFunc TlsPeerNameFunc) {
s.tlsPeerNameFunc = tlsPeerNameFunc
}
// Default TLS peer name function - returns the CN of the certificate
func defaultTlsPeerName(tlsConn *tls.Conn) (tlsPeer string, ok bool) {
state := tlsConn.ConnectionState()
if len(state.PeerCertificates) <= 0 {
return "", false
}
cn := state.PeerCertificates[0].Subject.CommonName
return cn, true
}
//Configure the server for listen on an UDP addr
func (s *Server) ListenUDP(addr string) error {
udpAddr, err := net.ResolveUDPAddr("udp", addr)
if err != nil {
return err
}
connection, err := net.ListenUDP("udp", udpAddr)
if err != nil {
return err
}
connection.SetReadBuffer(datagramReadBufferSize)
s.connections = append(s.connections, connection)
return nil
}
//Configure the server for listen on an unix socket
func (s *Server) ListenUnixgram(addr string) error {
unixAddr, err := net.ResolveUnixAddr("unixgram", addr)
if err != nil {
return err
}
connection, err := net.ListenUnixgram("unixgram", unixAddr)
if err != nil {
return err
}
connection.SetReadBuffer(datagramReadBufferSize)
s.connections = append(s.connections, connection)
return nil
}
//Configure the server for listen on a TCP addr
func (s *Server) ListenTCP(addr string) error {
tcpAddr, err := net.ResolveTCPAddr("tcp", addr)
if err != nil {
return err
}
listener, err := net.ListenTCP("tcp", tcpAddr)
if err != nil {
return err
}
s.doneTcp = make(chan bool)
s.listeners = append(s.listeners, listener)
return nil
}
//Configure the server for listen on a TCP addr for TLS
func (s *Server) ListenTCPTLS(addr string, config *tls.Config) error {
listener, err := tls.Listen("tcp", addr, config)
if err != nil {
return err
}
s.doneTcp = make(chan bool)
s.listeners = append(s.listeners, listener)
return nil
}
//Starts the server, all the go routines goes to live
func (s *Server) Boot() error {
if s.format == nil {
return errors.New("please set a valid format")
}
if s.handler == nil {
return errors.New("please set a valid handler")
}
for _, listener := range s.listeners {
s.goAcceptConnection(listener)
}
if len(s.connections) > 0 {
s.goParseDatagrams()
}
for _, connection := range s.connections {
s.goReceiveDatagrams(connection)
}
return nil
}
func (s *Server) goAcceptConnection(listener net.Listener) {
s.wait.Add(1)
go func(listener net.Listener) {
loop:
for {
select {
case <-s.doneTcp:
break loop
default:
}
connection, err := listener.Accept()
if err != nil {
continue
}
s.goScanConnection(connection)
}
s.wait.Done()
}(listener)
}
func (s *Server) goScanConnection(connection net.Conn) {
scanner := bufio.NewScanner(connection)
if sf := s.format.GetSplitFunc(); sf != nil {
scanner.Split(sf)
}
remoteAddr := connection.RemoteAddr()
var client string
if remoteAddr != nil {
client = remoteAddr.String()
}
tlsPeer := ""
if tlsConn, ok := connection.(*tls.Conn); ok {
// Handshake now so we get the TLS peer information
if err := tlsConn.Handshake(); err != nil {
connection.Close()
return
}
if s.tlsPeerNameFunc != nil {
var ok bool
tlsPeer, ok = s.tlsPeerNameFunc(tlsConn)
if !ok {
connection.Close()
return
}
}
}
var scanCloser *ScanCloser
scanCloser = &ScanCloser{scanner, connection}
s.wait.Add(1)
go s.scan(scanCloser, client, tlsPeer)
}
func (s *Server) scan(scanCloser *ScanCloser, client string, tlsPeer string) {
loop:
for {
select {
case <-s.doneTcp:
break loop
default:
}
if s.readTimeoutMilliseconds > 0 {
scanCloser.closer.SetReadDeadline(time.Now().Add(time.Duration(s.readTimeoutMilliseconds) * time.Millisecond))
}
if scanCloser.Scan() {
s.parser([]byte(scanCloser.Text()), client, tlsPeer)
} else {
break loop
}
}
scanCloser.closer.Close()
s.wait.Done()
}
func (s *Server) parser(line []byte, client string, tlsPeer string) {
parser := s.format.GetParser(line)
err := parser.Parse()
if err != nil {
s.lastError = err
}
logParts := parser.Dump()
logParts["client"] = client
if logParts["hostname"] == "" && (s.format == RFC3164 || s.format == Automatic) {
if i := strings.Index(client, ":"); i > 1 {
logParts["hostname"] = client[:i]
} else {
logParts["hostname"] = client
}
}
logParts["tls_peer"] = tlsPeer
s.handler.Handle(logParts, int64(len(line)), err)
}
//Returns the last error
func (s *Server) GetLastError() error {
return s.lastError
}
//Kill the server
func (s *Server) Kill() error {
for _, connection := range s.connections {
err := connection.Close()
if err != nil {
return err
}
}
for _, listener := range s.listeners {
err := listener.Close()
if err != nil {
return err
}
}
// Only need to close channel once to broadcast to all waiting
if s.doneTcp != nil {
close(s.doneTcp)
}
if s.datagramChannel != nil {
close(s.datagramChannel)
}
return nil
}
//Waits until the server stops
func (s *Server) Wait() {
s.wait.Wait()
}
type TimeoutCloser interface {
Close() error
SetReadDeadline(t time.Time) error
}
type ScanCloser struct {
*bufio.Scanner
closer TimeoutCloser
}
type DatagramMessage struct {
message []byte
client string
}
func (s *Server) goReceiveDatagrams(packetconn net.PacketConn) {
s.wait.Add(1)
go func() {
defer s.wait.Done()
for {
buf := s.datagramPool.Get().([]byte)
n, addr, err := packetconn.ReadFrom(buf)
if err == nil {
// Ignore trailing control characters and NULs
for ; (n > 0) && (buf[n-1] < 32); n-- {
}
if n > 0 {
var address string
if addr != nil {
address = addr.String()
}
s.datagramChannel <- DatagramMessage{buf[:n], address}
}
} else {
// there has been an error. Either the server has been killed
// or may be getting a transitory error due to (e.g.) the
// interface being shutdown in which case sleep() to avoid busy wait.
opError, ok := err.(*net.OpError)
if (ok) && !opError.Temporary() && !opError.Timeout() {
return
}
time.Sleep(10 * time.Millisecond)
}
}
}()
}
func (s *Server) goParseDatagrams() {
s.datagramChannel = make(chan DatagramMessage, datagramChannelBufferSize)
s.wait.Add(1)
go func() {
defer s.wait.Done()
for {
select {
case msg, ok := (<-s.datagramChannel):
if !ok {
return
}
if sf := s.format.GetSplitFunc(); sf != nil {
if _, token, err := sf(msg.message, true); err == nil {
s.parser(token, msg.client, "")
}
} else {
s.parser(msg.message, msg.client, "")
}
s.datagramPool.Put(msg.message[:cap(msg.message)])
}
}
}()
}