Skip to content

tun/netstack: fix race during (*netTun).Close() #134

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
134130 wants to merge 1 commit into
base: master
Choose a base branch
from
Open

tun/netstack: fix race during (*netTun).Close() #134

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
62 changes: 27 additions & 35 deletions tun/netstack/tun.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,14 +40,14 @@ import (
)

type netTun struct {
ep *channel.Endpoint
stack *stack.Stack
events chan tun.Event
notifyHandle *channel.NotificationHandle
incomingPacket chan *buffer.View
mtu int
dnsServers []netip.Addr
hasV4, hasV6 bool
ep *channel.Endpoint
stack *stack.Stack
events chan tun.Event
ctx context.Context
cancel context.CancelFunc
mtu int
dnsServers []netip.Addr
hasV4, hasV6 bool
}

type Net netTun
Expand All @@ -58,20 +58,23 @@ func CreateNetTUN(localAddresses, dnsServers []netip.Addr, mtu int) (tun.Device,
TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol, udp.NewProtocol, icmp.NewProtocol6, icmp.NewProtocol4},
HandleLocal: true,
}

ctx, cancel := context.WithCancel(context.Background())

dev := &netTun{
ep: channel.New(1024, uint32(mtu), ""),
stack: stack.New(opts),
events: make(chan tun.Event, 10),
incomingPacket: make(chan *buffer.View),
dnsServers: dnsServers,
mtu: mtu,
ep: channel.New(1024, uint32(mtu), ""),
stack: stack.New(opts),
events: make(chan tun.Event, 10),
ctx: ctx,
cancel: cancel,
dnsServers: dnsServers,
mtu: mtu,
}
sackEnabledOpt := tcpip.TCPSACKEnabled(true) // TCP SACK is disabled by default
tcpipErr := dev.stack.SetTransportProtocolOption(tcp.ProtocolNumber, &sackEnabledOpt)
if tcpipErr != nil {
return nil, nil, fmt.Errorf("could not enable TCP SACK: %v", tcpipErr)
}
dev.notifyHandle = dev.ep.AddNotify(dev)
tcpipErr = dev.stack.CreateNIC(1, dev.ep)
if tcpipErr != nil {
return nil, nil, fmt.Errorf("CreateNIC: %v", tcpipErr)
Expand Down Expand Up @@ -121,11 +124,12 @@ func (tun *netTun) Events() <-chan tun.Event {
}

func (tun *netTun) Read(buf [][]byte, sizes []int, offset int) (int, error) {
view, ok := <-tun.incomingPacket
if !ok {
pkb := tun.ep.ReadContext(tun.ctx)
if pkb == nil {
return 0, os.ErrClosed
}

view := pkb.ToView()
pkb.DecRef()
Copy link
Author

@134130 134130 Nov 29, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

need to add view.Release

n, err := view.Read(buf[0][offset:])
if err != nil {
return 0, err
Expand All @@ -135,6 +139,10 @@ func (tun *netTun) Read(buf [][]byte, sizes []int, offset int) (int, error) {
}

func (tun *netTun) Write(buf [][]byte, offset int) (int, error) {
if tun.ctx.Err() != nil {
return 0, os.ErrClosed
}

for _, buf := range buf {
packet := buf[offset:]
if len(packet) == 0 {
Expand All @@ -154,32 +162,16 @@ func (tun *netTun) Write(buf [][]byte, offset int) (int, error) {
return len(buf), nil
}

func (tun *netTun) WriteNotify() {
pkt := tun.ep.Read()
if pkt == nil {
return
}

view := pkt.ToView()
pkt.DecRef()

tun.incomingPacket <- view
}

func (tun *netTun) Close() error {
tun.cancel()
tun.stack.RemoveNIC(1)
tun.stack.Close()
tun.ep.RemoveNotify(tun.notifyHandle)
tun.ep.Close()

if tun.events != nil {
close(tun.events)
}

if tun.incomingPacket != nil {
close(tun.incomingPacket)
}

return nil
}

Expand Down