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p2p, p2p/discover, p2p/discv5: implement UDP port sharing (#15200)

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This commit affects p2p/discv5 "topic discovery" by running it on
the same UDP port where the old discovery works. This is realized
by giving an "unhandled" packet channel to the old v4 discovery
packet handler where all invalid packets are sent. These packets
are then processed by v5. v5 packets are always invalid when
interpreted by v4 and vice versa. This is ensured by adding one
to the first byte of the packet hash in v5 packets.

DiscoveryV5Bootnodes is also changed to point to new bootnodes
that are implementing the changed packet format with modified
hash. Existing and new v5 bootnodes are both running on different
ports ATM.
This commit is contained in:
Felföldi Zsolt
2018-01-22 13:38:34 +01:00
committed by Felix Lange
parent 02aeb3d766
commit 92580d69d3
17 changed files with 150 additions and 91 deletions
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44
p2p/discover/udp.go
View File

@ -210,17 +210,15 @@ type reply struct {
matched chan<- bool
}
// ReadPacket is sent to the unhandled channel when it could not be processed
type ReadPacket struct {
Data []byte
Addr *net.UDPAddr
}
// ListenUDP returns a new table that listens for UDP packets on laddr.
func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, error) {
addr, err := net.ResolveUDPAddr("udp", laddr)
if err != nil {
return nil, err
}
conn, err := net.ListenUDP("udp", addr)
if err != nil {
return nil, err
}
tab, _, err := newUDP(priv, conn, natm, nodeDBPath, netrestrict)
func ListenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr, unhandled chan ReadPacket, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, error) {
tab, _, err := newUDP(priv, conn, realaddr, unhandled, nodeDBPath, netrestrict)
if err != nil {
return nil, err
}
@ -228,7 +226,7 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBP
return tab, nil
}
func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, *udp, error) {
func newUDP(priv *ecdsa.PrivateKey, c conn, realaddr *net.UDPAddr, unhandled chan ReadPacket, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, *udp, error) {
udp := &udp{
conn: c,
priv: priv,
@ -237,16 +235,6 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath strin
gotreply: make(chan reply),
addpending: make(chan *pending),
}
realaddr := c.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}
}
}
// TODO: separate TCP port
udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
tab, err := newTable(udp, PubkeyID(&priv.PublicKey), realaddr, nodeDBPath)
@ -256,7 +244,7 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath strin
udp.Table = tab
go udp.loop()
go udp.readLoop()
go udp.readLoop(unhandled)
return udp.Table, udp, nil
}
@ -492,8 +480,11 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) ([]byte,
}
// readLoop runs in its own goroutine. it handles incoming UDP packets.
func (t *udp) readLoop() {
func (t *udp) readLoop(unhandled chan ReadPacket) {
defer t.conn.Close()
if unhandled != nil {
defer close(unhandled)
}
// Discovery packets are defined to be no larger than 1280 bytes.
// Packets larger than this size will be cut at the end and treated
// as invalid because their hash won't match.
@ -509,7 +500,12 @@ func (t *udp) readLoop() {
log.Debug("UDP read error", "err", err)
return
}
t.handlePacket(from, buf[:nbytes])
if t.handlePacket(from, buf[:nbytes]) != nil && unhandled != nil {
select {
case unhandled <- ReadPacket{buf[:nbytes], from}:
default:
}
}
}
}

3
p2p/discover/udp_test.go
View File

@ -70,7 +70,8 @@ func newUDPTest(t *testing.T) *udpTest {
remotekey: newkey(),
remoteaddr: &net.UDPAddr{IP: net.IP{10, 0, 1, 99}, Port: 30303},
}
test.table, test.udp, _ = newUDP(test.localkey, test.pipe, nil, "", nil)
realaddr := test.pipe.LocalAddr().(*net.UDPAddr)
test.table, test.udp, _ = newUDP(test.localkey, test.pipe, realaddr, nil, "", nil)
return test
}