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641a90ea33
For eventual use by net/udprelay.Server Updates tailscale/corp#31164 Signed-off-by: Jordan Whited <jordan@tailscale.com>
41 lines
1.2 KiB
Go
41 lines
1.2 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build linux
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package sockopts
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import (
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"net"
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"syscall"
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"tailscale.com/types/nettype"
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)
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// SetBufferSize sets pconn's buffer to size for direction. It attempts
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// (errForce) to set SO_SNDBUFFORCE or SO_RECVBUFFORCE which can overcome the
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// limit of net.core.{r,w}mem_max, but require CAP_NET_ADMIN. It falls back to
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// the portable implementation (errPortable) if that fails, which may be
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// silently capped to net.core.{r,w}mem_max.
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//
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// If pconn is not a [*net.UDPConn], then SetBufferSize is no-op.
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func SetBufferSize(pconn nettype.PacketConn, direction BufferDirection, size int) (errForce error, errPortable error) {
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opt := syscall.SO_RCVBUFFORCE
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if direction == WriteDirection {
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opt = syscall.SO_SNDBUFFORCE
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}
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if c, ok := pconn.(*net.UDPConn); ok {
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var rc syscall.RawConn
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rc, errForce = c.SyscallConn()
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if errForce == nil {
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rc.Control(func(fd uintptr) {
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errForce = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, opt, size)
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})
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}
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if errForce != nil {
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errPortable = portableSetBufferSize(pconn, direction, size)
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}
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}
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return errForce, errPortable
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}
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