40 lines
1.2 KiB
Go
40 lines
1.2 KiB
Go
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//go:build linux
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package quic
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import (
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"errors"
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"syscall"
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"github.com/lucas-clemente/quic-go/internal/utils"
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"golang.org/x/sys/unix"
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)
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func setDF(rawConn syscall.RawConn) error {
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// Enabling IP_MTU_DISCOVER will force the kernel to return "sendto: message too long"
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// and the datagram will not be fragmented
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var errDFIPv4, errDFIPv6 error
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if err := rawConn.Control(func(fd uintptr) {
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errDFIPv4 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_DO)
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errDFIPv6 = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_MTU_DISCOVER, unix.IPV6_PMTUDISC_DO)
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}); err != nil {
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return err
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}
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switch {
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case errDFIPv4 == nil && errDFIPv6 == nil:
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utils.DefaultLogger.Debugf("Setting DF for IPv4 and IPv6.")
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case errDFIPv4 == nil && errDFIPv6 != nil:
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utils.DefaultLogger.Debugf("Setting DF for IPv4.")
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case errDFIPv4 != nil && errDFIPv6 == nil:
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utils.DefaultLogger.Debugf("Setting DF for IPv6.")
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case errDFIPv4 != nil && errDFIPv6 != nil:
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return errors.New("setting DF failed for both IPv4 and IPv6")
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}
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return nil
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}
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func isMsgSizeErr(err error) bool {
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// https://man7.org/linux/man-pages/man7/udp.7.html
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return errors.Is(err, unix.EMSGSIZE)
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}
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