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packet_listener.go
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packet_listener.go
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package socket_listener
import (
"errors"
"fmt"
"net"
"net/url"
"os"
"strconv"
"strings"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
)
type packetListener struct {
Encoding string
MaxDecompressionSize int64
SocketMode string
ReadBufferSize int
Parser telegraf.Parser
Log telegraf.Logger
conn net.PacketConn
decoder internal.ContentDecoder
path string
}
func (l *packetListener) listen(acc telegraf.Accumulator) {
buf := make([]byte, 64*1024) // 64kb - maximum size of IP packet
for {
n, _, err := l.conn.ReadFrom(buf)
if err != nil {
if !strings.HasSuffix(err.Error(), ": use of closed network connection") {
acc.AddError(err)
}
break
}
body, err := l.decoder.Decode(buf[:n])
if err != nil {
acc.AddError(fmt.Errorf("unable to decode incoming packet: %w", err))
}
metrics, err := l.Parser.Parse(body)
if err != nil {
acc.AddError(fmt.Errorf("unable to parse incoming packet: %w", err))
// TODO rate limit
continue
}
for _, m := range metrics {
acc.AddMetric(m)
}
}
}
func (l *packetListener) setupUnixgram(u *url.URL, socketMode string) error {
err := os.Remove(u.Path)
if err != nil && !errors.Is(err, os.ErrNotExist) {
return fmt.Errorf("removing socket failed: %w", err)
}
conn, err := net.ListenPacket(u.Scheme, u.Path)
if err != nil {
return fmt.Errorf("listening (unixgram) failed: %w", err)
}
l.path = u.Path
l.conn = conn
// Set permissions on socket
if socketMode != "" {
// Convert from octal in string to int
i, err := strconv.ParseUint(socketMode, 8, 32)
if err != nil {
return fmt.Errorf("converting socket mode failed: %w", err)
}
perm := os.FileMode(uint32(i))
if err := os.Chmod(u.Path, perm); err != nil {
return fmt.Errorf("changing socket permissions failed: %w", err)
}
}
// Create a decoder for the given encoding
var options []internal.DecodingOption
if l.MaxDecompressionSize > 0 {
options = append(options, internal.WithMaxDecompressionSize(l.MaxDecompressionSize))
}
decoder, err := internal.NewContentDecoder(l.Encoding, options...)
if err != nil {
return fmt.Errorf("creating decoder failed: %w", err)
}
l.decoder = decoder
return nil
}
func (l *packetListener) setupUDP(u *url.URL, ifname string, bufferSize int) error {
var conn *net.UDPConn
addr, err := net.ResolveUDPAddr(u.Scheme, u.Host)
if err != nil {
return fmt.Errorf("resolving UDP address failed: %w", err)
}
if addr.IP.IsMulticast() {
var iface *net.Interface
if ifname != "" {
var err error
iface, err = net.InterfaceByName(ifname)
if err != nil {
return fmt.Errorf("resolving address of %q failed: %w", ifname, err)
}
}
conn, err = net.ListenMulticastUDP(u.Scheme, iface, addr)
if err != nil {
return fmt.Errorf("listening (udp multicast) failed: %w", err)
}
} else {
conn, err = net.ListenUDP(u.Scheme, addr)
if err != nil {
return fmt.Errorf("listening (udp) failed: %w", err)
}
}
if bufferSize > 0 {
if err := conn.SetReadBuffer(bufferSize); err != nil {
l.Log.Warnf("Setting read buffer on %s socket failed: %v", u.Scheme, err)
}
}
l.conn = conn
// Create a decoder for the given encoding
var options []internal.DecodingOption
if l.MaxDecompressionSize > 0 {
options = append(options, internal.WithMaxDecompressionSize(l.MaxDecompressionSize))
}
decoder, err := internal.NewContentDecoder(l.Encoding, options...)
if err != nil {
return fmt.Errorf("creating decoder failed: %w", err)
}
l.decoder = decoder
return nil
}
func (l *packetListener) setupIP(u *url.URL) error {
conn, err := net.ListenPacket(u.Scheme, u.Host)
if err != nil {
return fmt.Errorf("listening (ip) failed: %w", err)
}
l.conn = conn
// Create a decoder for the given encoding
var options []internal.DecodingOption
if l.MaxDecompressionSize > 0 {
options = append(options, internal.WithMaxDecompressionSize(l.MaxDecompressionSize))
}
decoder, err := internal.NewContentDecoder(l.Encoding, options...)
if err != nil {
return fmt.Errorf("creating decoder failed: %w", err)
}
l.decoder = decoder
return nil
}
func (l *packetListener) addr() net.Addr {
return l.conn.LocalAddr()
}
func (l *packetListener) close() error {
if err := l.conn.Close(); err != nil {
return err
}
if l.path != "" {
err := os.Remove(l.path)
if err != nil && !errors.Is(err, os.ErrNotExist) {
// Ignore file-not-exists errors when removing the socket
return err
}
}
return nil
}