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p2p/discover: fix race in ListenUDP 

udp.Table was assigned after the readLoop started, so
packets could arrive and be processed before the Table was there.
This commit is contained in:
Felix Lange 2015-02-13 15:04:30 +01:00
parent 5cc1256fd6
commit cf754b9483
1 changed files with 17 additions and 24 deletions
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41
p2p/discover/udp.go
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@ -124,35 +124,14 @@ type reply struct {
// ListenUDP returns a new table that listens for UDP packets on laddr.
func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface) (*Table, error) {
t, realaddr, err := listen(priv, laddr, natm)
addr, err := net.ResolveUDPAddr("udp", laddr)
if err != nil {
return nil, err
}
if natm != nil {
if !realaddr.IP.IsLoopback() {
go nat.Map(natm, t.closing, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
}
// TODO: react to external IP changes over time.
if ext, err := natm.ExternalIP(); err == nil {
realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
}
}
t.Table = newTable(t, PubkeyID(&priv.PublicKey), realaddr)
log.Infoln("Listening, ", t.self)
return t.Table, nil
}
func listen(priv *ecdsa.PrivateKey, laddr string, nat nat.Interface) (*udp, *net.UDPAddr, error) {
addr, err := net.ResolveUDPAddr("udp", laddr)
if err != nil {
return nil, nil, err
}
conn, err := net.ListenUDP("udp", addr)
if err != nil {
return nil, nil, err
return nil, err
}
realaddr := conn.LocalAddr().(*net.UDPAddr)
udp := &udp{
conn: conn,
priv: priv,
@ -160,9 +139,23 @@ func listen(priv *ecdsa.PrivateKey, laddr string, nat nat.Interface) (*udp, *net
addpending: make(chan *pending),
replies: make(chan reply),
}
realaddr := conn.LocalAddr().(*net.UDPAddr)
if natm != nil {
if !realaddr.IP.IsLoopback() {
go nat.Map(natm, udp.closing, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
}
// TODO: react to external IP changes over time.
if ext, err := natm.ExternalIP(); err == nil {
realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
}
}
udp.Table = newTable(udp, PubkeyID(&priv.PublicKey), realaddr)
go udp.loop()
go udp.readLoop()
return udp, realaddr, nil
log.Infoln("Listening, ", udp.self)
return udp.Table, nil
}
func (t *udp) close() {