mirror of
https://github.com/refraction-networking/uquic.git
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2bcfe5bc4b
* check for WSAEMSGSIZE errors when receiving UDP packets on Windows * check EMSGSIZE error on macOS
80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
//go:build linux
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package quic
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import (
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"errors"
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"log"
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"os"
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"strconv"
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"syscall"
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"unsafe"
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"golang.org/x/sys/unix"
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"github.com/quic-go/quic-go/internal/utils"
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)
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func setDF(rawConn syscall.RawConn) (bool, 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 false, 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 false, errors.New("setting DF failed for both IPv4 and IPv6")
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}
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return true, nil
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}
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func maybeSetGSO(rawConn syscall.RawConn) bool {
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enable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_ENABLE_GSO"))
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if !enable {
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return false
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}
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var setErr error
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if err := rawConn.Control(func(fd uintptr) {
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setErr = unix.SetsockoptInt(int(fd), syscall.IPPROTO_UDP, unix.UDP_SEGMENT, 1)
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}); err != nil {
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setErr = err
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}
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if setErr != nil {
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log.Println("failed to enable GSO")
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return false
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}
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return true
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}
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func isSendMsgSizeErr(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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func isRecvMsgSizeErr(err error) bool { return false }
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func appendUDPSegmentSizeMsg(b []byte, size uint16) []byte {
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startLen := len(b)
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const dataLen = 2 // payload is a uint16
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b = append(b, make([]byte, unix.CmsgSpace(dataLen))...)
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h := (*unix.Cmsghdr)(unsafe.Pointer(&b[startLen]))
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h.Level = syscall.IPPROTO_UDP
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h.Type = unix.UDP_SEGMENT
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h.SetLen(unix.CmsgLen(dataLen))
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// UnixRights uses the private `data` method, but I *think* this achieves the same goal.
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offset := startLen + unix.CmsgSpace(0)
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*(*uint16)(unsafe.Pointer(&b[offset])) = size
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return b
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}
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