tailscale/net/neterror/neterror_linux.go
Jordan Whited f475e5550c
net/neterror, wgengine/magicsock: use UDP GSO and GRO on Linux (#7791)
This commit implements UDP offloading for Linux. GSO size is passed to
and from the kernel via socket control messages. Support is probed at
runtime.

UDP GSO is dependent on checksum offload support on the egress netdev.
UDP GSO will be disabled in the event sendmmsg() returns EIO, which is
a strong signal that the egress netdev does not support checksum
offload.

Updates tailscale/corp#8734

Signed-off-by: Jordan Whited <jordan@tailscale.com>
2023-04-04 16:32:16 -07:00

27 lines
768 B
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package neterror
import (
"errors"
"os"
"golang.org/x/sys/unix"
)
func init() {
shouldDisableUDPGSO = func(err error) bool {
var serr *os.SyscallError
if errors.As(err, &serr) {
// EIO is returned by udp_send_skb() if the device driver does not
// have tx checksumming enabled, which is a hard requirement of
// UDP_SEGMENT. See:
// https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man7/udp.7?id=806eabd74910447f21005160e90957bde4db0183#n228
// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/udp.c?h=v6.2&id=c9c3395d5e3dcc6daee66c6908354d47bf98cb0c#n942
return serr.Err == unix.EIO
}
return false
}
}