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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
Download Patch File Download Diff File Expand all files Collapse all files

46
p2p/discv5/udp.go
View File

@ -37,7 +37,7 @@ const Version = 4
// Errors
var (
errPacketTooSmall = errors.New("too small")
errBadHash = errors.New("bad hash")
errBadPrefix = errors.New("bad prefix")
errExpired = errors.New("expired")
errUnsolicitedReply = errors.New("unsolicited reply")
errUnknownNode = errors.New("unknown node")
@ -145,10 +145,11 @@ type (
}
)
const (
macSize = 256 / 8
sigSize = 520 / 8
headSize = macSize + sigSize // space of packet frame data
var (
versionPrefix = []byte("temporary discovery v5")
versionPrefixSize = len(versionPrefix)
sigSize = 520 / 8
headSize = versionPrefixSize + sigSize // space of packet frame data
)
// Neighbors replies are sent across multiple packets to
@ -237,12 +238,12 @@ type udp struct {
}
// 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) (*Network, error) {
transport, err := listenUDP(priv, laddr)
func ListenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr, nodeDBPath string, netrestrict *netutil.Netlist) (*Network, error) {
transport, err := listenUDP(priv, conn, realaddr)
if err != nil {
return nil, err
}
net, err := newNetwork(transport, priv.PublicKey, natm, nodeDBPath, netrestrict)
net, err := newNetwork(transport, priv.PublicKey, nodeDBPath, netrestrict)
if err != nil {
return nil, err
}
@ -251,16 +252,8 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBP
return net, nil
}
func listenUDP(priv *ecdsa.PrivateKey, laddr string) (*udp, 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
}
return &udp{conn: conn, priv: priv, ourEndpoint: makeEndpoint(addr, uint16(addr.Port))}, nil
func listenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr) (*udp, error) {
return &udp{conn: conn, priv: priv, ourEndpoint: makeEndpoint(realaddr, uint16(realaddr.Port))}, nil
}
func (t *udp) localAddr() *net.UDPAddr {
@ -372,11 +365,9 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) (p, hash
log.Error(fmt.Sprint("could not sign packet:", err))
return nil, nil, err
}
copy(packet[macSize:], sig)
// add the hash to the front. Note: this doesn't protect the
// packet in any way.
hash = crypto.Keccak256(packet[macSize:])
copy(packet, hash)
copy(packet, versionPrefix)
copy(packet[versionPrefixSize:], sig)
hash = crypto.Keccak256(packet[versionPrefixSize:])
return packet, hash, nil
}
@ -420,17 +411,16 @@ func decodePacket(buffer []byte, pkt *ingressPacket) error {
}
buf := make([]byte, len(buffer))
copy(buf, buffer)
hash, sig, sigdata := buf[:macSize], buf[macSize:headSize], buf[headSize:]
shouldhash := crypto.Keccak256(buf[macSize:])
if !bytes.Equal(hash, shouldhash) {
return errBadHash
prefix, sig, sigdata := buf[:versionPrefixSize], buf[versionPrefixSize:headSize], buf[headSize:]
if !bytes.Equal(prefix, versionPrefix) {
return errBadPrefix
}
fromID, err := recoverNodeID(crypto.Keccak256(buf[headSize:]), sig)
if err != nil {
return err
}
pkt.rawData = buf
pkt.hash = hash
pkt.hash = crypto.Keccak256(buf[versionPrefixSize:])
pkt.remoteID = fromID
switch pkt.ev = nodeEvent(sigdata[0]); pkt.ev {
case pingPacket: