github.com/metacubex/quic-go@v0.44.1-0.20240520163451-20b689a59136/sys_conn_df_linux.go (about) 1 //go:build linux 2 3 package quic 4 5 import ( 6 "errors" 7 "syscall" 8 9 "golang.org/x/sys/unix" 10 11 "github.com/metacubex/quic-go/internal/utils" 12 ) 13 14 func setDF(rawConn syscall.RawConn) (bool, error) { 15 // Enabling IP_MTU_DISCOVER will force the kernel to return "sendto: message too long" 16 // and the datagram will not be fragmented 17 var errDFIPv4, errDFIPv6 error 18 if err := rawConn.Control(func(fd uintptr) { 19 errDFIPv4 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_DO) 20 errDFIPv6 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_MTU_DISCOVER, unix.IPV6_PMTUDISC_DO) 21 }); err != nil { 22 return false, err 23 } 24 switch { 25 case errDFIPv4 == nil && errDFIPv6 == nil: 26 utils.DefaultLogger.Debugf("Setting DF for IPv4 and IPv6.") 27 case errDFIPv4 == nil && errDFIPv6 != nil: 28 utils.DefaultLogger.Debugf("Setting DF for IPv4.") 29 case errDFIPv4 != nil && errDFIPv6 == nil: 30 utils.DefaultLogger.Debugf("Setting DF for IPv6.") 31 case errDFIPv4 != nil && errDFIPv6 != nil: 32 utils.DefaultLogger.Debugf("Setting DF failed for both IPv4 and IPv6.") 33 } 34 return true, nil 35 } 36 37 func isSendMsgSizeErr(err error) bool { 38 // https://man7.org/linux/man-pages/man7/udp.7.html 39 return errors.Is(err, unix.EMSGSIZE) 40 } 41 42 func isRecvMsgSizeErr(error) bool { return false }