WIP- Fabric gossip component

This is a commit that contains only APIs and protobuff
The API between the ledger and the gossip component is in gossip/api/api.go

Change-Id: I9f6aef85f3b03e2d3a6b9850148e9cf4d1a93ce3
Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>

gossip/api/api.go

@@ -0,0 +1,93 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package api
+
+import (
+ "github.com/hyperledger/fabric/gossip/discovery"
+ "google.golang.org/grpc"
+)
+
+type GossipEmitterFactory interface {
+ NewGossipEmitter(id string, discSvc discovery.DiscoveryService) GossipService
+}
+
+// GossipService is used to publish new blocks to the gossip network
+type GossipService interface {
+ // payload: Holds the block's content, hash and seqNum
+ Publish(payload Payload) error
+}
+
+type BindAddress struct {
+ Host string
+ Port int16
+}
+
+// Payload defines an object that contains a ledger block
+type Payload struct {
+ Data []byte // The content of the message, possibly encrypted or signed
+ Hash string // The message hash
+ SeqNum uint64 // The message sequence number
+}
+
+type GossipMemberFactory interface {
+ NewGossipMember(discovery.DiscoveryService, ReplicationProvider, MessageCryptoService, MessagePolicyVerifier, *grpc.Server) GossipMember
+
+ NewGossipMemberWithRPCServer(discovery.DiscoveryService, ReplicationProvider, MessageCryptoService, MessagePolicyVerifier, BindAddress) (GossipMember, error)
+}
+
+// GossipMember is used to obtain new blocks from the gossip network
+type GossipMember interface {
+ // RegisterCallback registers a callback that is invoked on messages
+ // from startSeq to endSeq and invokes the callback when they arrive
+ RegisterCallback(startSeq uint64, endSeq uint64, callback func([]Payload))
+}
+
+// ReplicationProvider used by the GossipMember in order to obtain Blocks of
+// certain seqNum range to be sent to the requester
+type ReplicationProvider interface {
+ // GetData used by the gossip component to obtain certain blocks from the ledger.
+ // Returns the blocks requested with the given sequence numbers, or an error if
+ // some block requested is not available.
+ GetData(startSeqNum uint64, endSeqNum uint64) ([]Payload, error)
+
+ // LastBlockSeq used by the gossip component to obtain the last sequence of a block the ledger has.
+ LastBlockSeq() uint64
+}
+
+// MessageCryptoVerifier verifies the message's authenticity,
+// if messages are cryptographically signed
+type MessageCryptoService interface {
+ // Verify returns nil whether the message and its identifier are authentic,
+ // otherwise returns an error
+ Verify(seqNum uint64, sender string, payload Payload) error
+
+ // Sign signs the payload
+ Sign(sender string, Payload Payload) Payload
+
+ // SignBlob signs a blob
+ SignBlob([]byte) []byte
+
+ // VerifyBlob verifies a blob, returns error on failure
+ // and nil if the blob is correctly signed
+ VerifyBlob(sender string, blob []byte) error
+}
+
+// MessagePolicyVerifier verifies whether the message conforms to all required policies,
+// and can be safely delivered to the user.
+type MessagePolicyVerifier interface {
+ Verify(seqNum uint64, sender string, payload Payload) error
+}

gossip/comm/comm.go

@@ -0,0 +1,53 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package comm
+
+import (
+ "github.com/hyperledger/fabric/gossip/proto"
+ "sync"
+)
+
+type CommModule interface {
+ // Send sends a message to endpoints
+ Send(msg *proto.GossipMessage, endpoints ...string)
+
+ // Probe probes a remote node and returns nil if its responsive
+ Probe(endpoint string) error
+
+ // Accept returns a dedicated read-only channel for messages sent by other nodes that match a certain predicate.
+ // Each message from the channel can be used to send a reply back to the sender
+ Accept(MessageAcceptor) <-chan *ReceivedMessage
+
+ // PresumedDead returns a read-only channel for node endpoints that are suspected to be offline
+ PresumedDead() <-chan string
+
+ // CloseConn closes a connection to a certain endpoint
+ CloseConn(endpoint string)
+
+ // Stop stops the module
+ Stop()
+}
+
+
+type MessageAcceptor func(*proto.GossipMessage) bool
+
+type ReceivedMessage struct {
+ *proto.GossipMessage
+ lock *sync.Mutex
+ srvStream proto.Gossip_GossipStreamServer
+ clStream proto.Gossip_GossipStreamClient
+}

gossip/discovery/discovery.go

@@ -0,0 +1,78 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package discovery
+
+import "github.com/hyperledger/fabric/gossip/proto"
+
+// CryptoService is an interface that the discovery expects to be implemented and passed on creation
+type CryptoService interface {
+ // validateAliveMsg validates that an Alive message is authentic
+ ValidateAliveMsg(*proto.AliveMessage) bool
+
+ // SignMessage signs an AliveMessage and updates its signature field
+ SignMessage(*proto.AliveMessage) *proto.AliveMessage
+}
+
+// CommService is an interface that the discovery expects to be implemented and passed on creation
+type CommService interface {
+ // Gossip gossips a message
+ Gossip(msg *proto.GossipMessage)
+
+ // SendToPeer sends to a given peer a message.
+ // The nonce can be anything since the communication module handles the nonce itself
+ SendToPeer(peer *NetworkMember, msg *proto.GossipMessage)
+
+ // Ping probes a remote peer and returns if it's responsive or not
+ Ping(peer *NetworkMember) bool
+
+ // Accept returns a read-only channel for membership messages sent from remote peers
+ Accept() <-chan GossipMsg
+
+ // PresumedDead returns a read-only channel for peers that are presumed to be dead
+ PresumedDead() <-chan string
+
+ // CloseConn orders to close the connection with a certain peer
+ CloseConn(id string)
+}
+
+type GossipMsg interface {
+ GetGossipMessage() *proto.GossipMessage
+}
+
+type NetworkMember struct {
+ Id string
+ Endpoint string
+ Metadata []byte
+}
+
+type DiscoveryService interface {
+
+ // Self returns this instance's membership information
+ Self() NetworkMember
+
+ // UpdateMetadata updates this instance's metadata
+ UpdateMetadata([]byte)
+
+ // UpdateEndpoint updates this instance's endpoint
+ UpdateEndpoint(string)
+
+ // Stops this instance
+ Stop()
+
+ // GetMembership returns the alive members in the view
+ GetMembership() []NetworkMember
+}

gossip/gossip/gossip.go

@@ -0,0 +1,60 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package gossip
+
+import (
+ "github.com/hyperledger/fabric/gossip/discovery"
+ "github.com/hyperledger/fabric/gossip/proto"
+ "time"
+)
+
+type GossipService interface {
+
+ // GetPeersMetadata returns a mapping of endpoint --> metadata
+ GetPeersMetadata() map[string][]byte
+
+ // UpdateMetadata updates the self metadata of the discovery layer
+ UpdateMetadata([]byte)
+
+ // Gossip sends a message to other peers to the network
+ Gossip(msg *proto.GossipMessage)
+
+ // Accept returns a channel that outputs messages from other peers
+ Accept(MessageAcceptor) <-chan *proto.GossipMessage
+
+ // Stop stops the gossip component
+ Stop()
+}
+
+type MessageAcceptor func(*proto.GossipMessage) bool
+
+type GossipConfig struct {
+ BindPort int
+ Id string
+ SelfEndpoint string
+ BootstrapPeers []*discovery.NetworkMember
+ PropagateIterations int
+ PropagatePeerNum int
+
+ MaxMessageCountToStore int
+
+ MaxPropagationBurstSize int
+ MaxPropagationBurstLatency time.Duration
+
+ PullInterval time.Duration
+ PullPeerNum int
+}