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//go:build linux
package quic
import (
"errors"
"syscall"
"golang.org/x/sys/unix"
"github.com/quic-go/quic-go/internal/utils"
)
func setDF(rawConn syscall.RawConn) (bool, error) {
// Enabling IP_MTU_DISCOVER will force the kernel to return "sendto: message too long"
// and the datagram will not be fragmented
var errDFIPv4, errDFIPv6 error
if err := rawConn.Control(func(fd uintptr) {
errDFIPv4 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_PROBE)
errDFIPv6 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_MTU_DISCOVER, unix.IPV6_PMTUDISC_PROBE)
}); err != nil {
return false, err
}
switch {
case errDFIPv4 == nil && errDFIPv6 == nil:
utils.DefaultLogger.Debugf("Setting DF for IPv4 and IPv6.")
case errDFIPv4 == nil && errDFIPv6 != nil:
utils.DefaultLogger.Debugf("Setting DF for IPv4.")
case errDFIPv4 != nil && errDFIPv6 == nil:
utils.DefaultLogger.Debugf("Setting DF for IPv6.")
case errDFIPv4 != nil && errDFIPv6 != nil:
return false, errors.New("setting DF failed for both IPv4 and IPv6")
}
return true, nil
}
func isSendMsgSizeErr(err error) bool {
// https://man7.org/linux/man-pages/man7/udp.7.html
return errors.Is(err, unix.EMSGSIZE)
}
func isRecvMsgSizeErr(error) bool { return false }
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