// Must be called from the processing goroutine.
func processNack(node uint16, conn *connect.BaseConn, content []byte) {
var msg coproto.Nack
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
store.StartTransaction()
defer store.EndTransaction()
// If we don't consider ourselves the leader, discard.
if !amLeader {
return
}
msgProposal, msgLeader := *msg.Proposal, uint16(*msg.Leader)
proposal, leader := store.Proposal()
if msgProposal == proposal && msgLeader == leader {
return
}
if store.CompareProposals(msgProposal, msgLeader, proposal, leader) {
stopBeingLeader()
store.SetProposal(msgProposal, msgLeader)
}
}
// Must be called from the processing goroutine.
func processAccept(node uint16, conn *connect.BaseConn, content []byte) {
var msg coproto.Accept
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
store.StartTransaction()
defer store.EndTransaction()
proposal, leader := store.Proposal()
msgProposal, msgLeader := *msg.Proposal, node
if proposal != msgProposal || leader != msgLeader {
// Send a nack message and return,
// if this accept relates to an earlier proposal.
if store.CompareProposals(proposal, leader, msgProposal,
msgLeader) {
var nack coproto.Nack
nack.Proposal = new(uint64)
nack.Leader = new(uint32)
*nack.Proposal = proposal
*nack.Leader = uint32(leader)
conn.SendProto(6, &nack)
return
}
store.SetProposal(msgProposal, msgLeader)
}
addAccept(node, &msg)
}
// Must be called from the processing goroutine.
func processPromise(node uint16, conn *connect.BaseConn, content []byte) {
var msg coproto.Promise
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
store.StartTransaction()
defer store.EndTransaction()
if receivedPromises == nil {
// Not attempting to become leader.
log.Print("core/consensus: discarded promise, not becoming "+
"leader, from ", node)
return
}
proposal, leader := store.Proposal()
if proposal != *msg.Proposal || leader != uint16(*msg.Leader) {
log.Print("core/consensus: rejected promise for wrong "+
"proposal number from ", node)
return
}
if receivedPromises[node] != nil {
// Protocol violation; shouldn't get duplicate promises.
log.Print("core/consensus: PROTOCOL VIOLATION: received "+
"duplicate promise from node ", node)
return
}
log.Print("core/consensus: received promise from node ", node)
addPromise(node, &msg)
}
// Must be called from the processing goroutine.
func processAccepted(node uint16, conn *connect.BaseConn, content []byte) {
var msg coproto.Accepted
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
store.StartTransaction()
defer store.EndTransaction()
addAccepted(node, &msg)
}
func handleConn(node uint16, conn *connect.BaseConn) {
for {
msg, ok := <-conn.Received
if !ok {
break
}
// We only have one message type.
if *msg.MsgType != 2 {
conn.Close()
}
handleForward(conn, msg.Content)
}
terminatedConnCh <- receivedConn{node: node, conn: conn}
}
func handleForward(conn *connect.BaseConn, content []byte) {
var msg rproto.Forward
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
userMsg := new(UserMessage)
userMsg.Sender = *msg.Sender
userMsg.Recipient = *msg.Recipient
userMsg.Tag = *msg.Tag
userMsg.Content = *msg.Content
userMsg.Ttl = uint16(*msg.Ttl)
// Call message received callback.
for _, cb := range receivedCallbacks {
cb(userMsg)
}
}
func incomingConn(node uint16, conn *connect.BaseConn) {
store.StartTransaction()
if store.Degraded() {
conn.Close()
store.EndTransaction()
return
}
userConn := new(userConn)
userConn.conn = conn
userConn.deliver = make(chan *relay.UserMessage, 100)
// Add to connections set.
connectionsLock.Lock()
connections[userConn] = true
connectionsLock.Unlock()
store.EndTransaction()
go handleConn(userConn)
}
func handleMsg(node uint16, conn *connect.BaseConn, msg *baseproto.Message) {
if *msg.MsgType == 2 {
// Change Forward message.
forward := new(chproto.ChangeForward)
err := proto.Unmarshal(msg.Content, forward)
if err != nil {
conn.Close()
}
// If this is not a core node,
// and the requesting node is not this node,
// discard the message.
if uint16(*forward.Request.RequestNode) != config.Id() &&
!config.IsCore() {
return
}
// Send a Change Forward Ack message to the sender.
ack := new(chproto.ChangeForwardAck)
ack.RequestNode = forward.Request.RequestNode
ack.RequestId = forward.Request.RequestId
conn.SendProto(3, ack)
// Send the forward message to our processing goroutine.
receivedForwardCh <- receivedForward{forward: forward,
node: node}
} else if *msg.MsgType == 3 {
// Change Forward Ack message.
ack := new(chproto.ChangeForwardAck)
err := proto.Unmarshal(msg.Content, ack)
if err != nil {
conn.Close()
}
// Send the ack message to our processing goroutine.
receivedAckCh <- receivedAck{ack: ack, node: node}
} else {
// Unknown message.
conn.Close()
}
}
// Must be called from the processing goroutine.
func processPrepare(node uint16, conn *connect.BaseConn, content []byte) {
var msg coproto.Prepare
if err := proto.Unmarshal(content, &msg); err != nil {
conn.Close()
return
}
store.StartTransaction()
defer store.EndTransaction()
newProposal, newLeader := *msg.Proposal, node
proposal, leader := store.Proposal()
if store.CompareProposals(newProposal, newLeader, proposal, leader) {
log.Print("core/consensus: sending promise to ", newLeader)
// Create a promise message to send back.
var promise coproto.Promise
promise.Proposal = new(uint64)
promise.Leader = new(uint32)
promise.PrevProposal = new(uint64)
promise.PrevLeader = new(uint32)
*promise.Proposal = newProposal
*promise.Leader = uint32(newLeader)
*promise.PrevProposal = proposal
*promise.PrevLeader = uint32(leader)
// Add all the instructions we've previously accepted or chosen.
slots := store.InstructionSlots()
theirFirstUnapplied := *msg.FirstUnapplied
ourStart := store.InstructionStart()
relativeSlot := int(theirFirstUnapplied - ourStart)
if relativeSlot < 0 {
relativeSlot = 0
}
var accepted []*coproto.Instruction
for ; relativeSlot < len(slots); relativeSlot++ {
slot := slots[relativeSlot]
slotNum := ourStart + uint64(relativeSlot)
for i, _ := range slot {
if slot[i].IsChosen() {
appendInst(&accepted, slotNum, slot[i])
break
}
weAccepted := false
for _, node := range slot[i].Accepted() {
if node == config.Id() {
weAccepted = true
break
}
}
if weAccepted {
appendInst(&accepted, slotNum, slot[i])
break
}
}
}
// Send promise message.
conn.SendProto(3, &promise)
// Accept the other node as our new leader.
store.SetProposal(newProposal, newLeader)
} else {
var nack coproto.Nack
nack.Proposal = new(uint64)
nack.Leader = new(uint32)
*nack.Proposal = proposal
*nack.Leader = uint32(leader)
conn.SendProto(6, &nack)
}
}