tailscale/wgengine/magicsock/blockforever_conn.go

56 lines
1.4 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package magicsock
import (
"errors"
"net"
"net/netip"
"sync"
"syscall"
"time"
)
// blockForeverConn is a net.PacketConn whose reads block until it is closed.
type blockForeverConn struct {
mu sync.Mutex
cond *sync.Cond
closed bool
}
func (c *blockForeverConn) ReadFromUDPAddrPort(p []byte) (n int, addr netip.AddrPort, err error) {
c.mu.Lock()
for !c.closed {
c.cond.Wait()
}
c.mu.Unlock()
return 0, netip.AddrPort{}, net.ErrClosed
}
func (c *blockForeverConn) WriteToUDPAddrPort(p []byte, addr netip.AddrPort) (int, error) {
// Silently drop writes.
return len(p), nil
}
func (c *blockForeverConn) LocalAddr() net.Addr {
// Return a *net.UDPAddr because lots of code assumes that it will.
return new(net.UDPAddr)
}
func (c *blockForeverConn) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.closed {
return net.ErrClosed
}
c.closed = true
c.cond.Broadcast()
return nil
}
func (c *blockForeverConn) SetDeadline(t time.Time) error { return errors.New("unimplemented") }
func (c *blockForeverConn) SetReadDeadline(t time.Time) error { return errors.New("unimplemented") }
func (c *blockForeverConn) SetWriteDeadline(t time.Time) error { return errors.New("unimplemented") }
func (c *blockForeverConn) SyscallConn() (syscall.RawConn, error) { return nil, errUnsupportedConnType }