fb8d8d8fca
runtime.GOOS=="android" (not "linux"), so StdNetBind enabled UDP_GRO and read rxOffload=true, but the GRO receive dispatcher in bind_std.go is gated on GOOS=="linux" → dead on android. A coalesced GRO super-packet was read as one datagram, corrupting the WG transport stream → download died on no-detour WG-endpoint (detour path uses ClientBind, no offload, so it worked). Gate both the UDP_GRO setsockopt (controlfns_linux.go) and the rxOffload readback (features_linux.go) behind !android. TX/GSO untouched, so non-android linux performance is unchanged. Confirmed on device (CPH2411/Android-15: probe gave rxOffload=true + dispatch=single). See SPECS/010-B-O-WG_ENDPOINT_GRO_SPLIT_BRAIN.
52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
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*/
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package conn
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import (
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"net"
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"runtime"
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"golang.org/x/sys/unix"
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)
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const (
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// TODO: upstream to x/sys/unix
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socketOptionLevelUDP = 17
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socketOptionUDPSegment = 103
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socketOptionUDPGRO = 104
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)
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func supportsUDPOffload(conn *net.UDPConn) (txOffload, rxOffload bool) {
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rc, err := conn.SyscallConn()
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if err != nil {
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return
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}
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err = rc.Control(func(fd uintptr) {
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_, errSyscall := unix.GetsockoptInt(int(fd), unix.IPPROTO_UDP, socketOptionUDPSegment)
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if errSyscall != nil {
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return
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}
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txOffload = true
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// lx(010): never advertise RX offload on android. runtime.GOOS=="android"
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// (not "linux"), so the GRO receive dispatcher in bind_std.go (gated on
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// GOOS=="linux") is dead there — a coalesced GRO super-packet would be read
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// as one datagram and corrupt the WG transport stream, killing download.
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// Confirmed on device (CPH2411/Android-15: rxOffload=true, dispatch=single).
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// TX is left untouched. See SPECS/010-B-O-WG_ENDPOINT_GRO_SPLIT_BRAIN.
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if runtime.GOOS == "android" {
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return
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}
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opt, errSyscall := unix.GetsockoptInt(int(fd), unix.IPPROTO_UDP, socketOptionUDPGRO)
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if errSyscall != nil {
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return
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}
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rxOffload = opt == 1
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})
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if err != nil {
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return false, false
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}
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return txOffload, rxOffload
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}
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