// startBrokerClient starts an individual broker client.
// It takes as input the broker information.
func (p *Publisher) startBrokerClient(broker brokerInfo) {
var opts []grpc.DialOption
opts = append(opts, grpc.WithInsecure(), grpc.WithBlock())
conn, err := grpc.Dial(broker.addr, opts...)
if err != nil {
fmt.Printf("Error while connecting to server: %v\n", err)
return
}
defer conn.Close()
client := pb.NewPubBrokerClient(conn)
ch := p.addChannel(broker.id)
for {
pub := <-ch
pub.MAC = common.CreatePublicationMAC(&pub, p.brokers[broker.id].key)
// Handle publish request and response
resp, err := client.Publish(context.Background(), &pub)
if err != nil {
fmt.Printf("Error publishing to %v, %v\n", broker.id, err)
p.statusCh <- -1
continue
}
p.statusCh <- resp.Status
}
}
// addMACsRecursive adds MACs to the chain of MACs.
// It takes as input the publication,
// the current node ID string in the tree (should start with the local node's children),
// and the number of generations to add.
func (p *Publisher) addMACs(pub *pb.Publication, currentStr string, generations uint64) {
if generations > 1 {
// Add MACs for all the children
for _, childStr := range p.chainNodes[currentStr].children {
chainMAC := pb.ChainMAC{
From: p.localStr,
To: childStr,
MAC: common.CreatePublicationMAC(pub, p.chainNodes[childStr].key),
}
pub.ChainMACs = append(pub.ChainMACs, &chainMAC)
// Recursively add child macs for next generation
p.addMACs(pub, childStr, generations-1)
}
}
}
// addMACsRecursive adds MACs to the chain of MACs. Some older MACs may need to be kept depending
// on the number of generations in the chain.
// It takes as input the new publication,
// the old publication,
// the current node ID string in the tree (should start with the local node's children),
// and the number of generations to add.
func (b *Broker) addMACsRecursive(pub *pb.Publication, oldPub *pb.Publication, currentStr string, generations uint64) {
// Add any old chain MACs that add going to the child node
for _, oldChainMAC := range oldPub.ChainMACs {
if oldChainMAC.To == currentStr {
pub.ChainMACs = append(pub.ChainMACs, oldChainMAC)
}
}
if generations > 1 {
// Add MACs for all the broker children
for _, childStr := range b.chainNodes[currentStr].children {
addMAC := true
// Check if the subscriber is subscribed to this topic
if strings.HasPrefix(childStr, "S") {
childID, _ := strconv.ParseUint(childStr[1:], 10, 64)
b.subscribersMutex.RLock()
if b.subscribers[childID].topics[pub.TopicID] == false {
// Don't add the MAC is the subscriber isn't interested in this topic
addMAC = false
}
b.subscribersMutex.RUnlock()
}
if addMAC {
chainMAC := pb.ChainMAC{
From: b.localStr,
To: childStr,
MAC: common.CreatePublicationMAC(pub, b.chainNodes[childStr].key),
}
pub.ChainMACs = append(pub.ChainMACs, &chainMAC)
// Recursively add child macs for next generation
b.addMACsRecursive(pub, oldPub, childStr, generations-1)
}
}
}
}
// Subscribe handles incoming Subscribe requests from subscribers
func (b *Broker) Subscribe(stream pb.SubBroker_SubscribeServer) error {
// Read initial subscribe message
req, err := stream.Recv()
if err == io.EOF {
return err
} else if err != nil {
return err
}
subscriber, exists := b.subscribers[req.SubscriberID]
// Check MAC
if !exists || common.CheckSubscriptionMAC(req, req.MAC, subscriber.key) == false {
fmt.Printf("***BAD MAC: Subscribe*** %v\n", *req)
return fmt.Errorf("***BAD MAC: Subscribe*** %v\n", *req)
}
id := req.SubscriberID
ch := b.addToSubChannel(id)
// Add initial subscribe for processing
b.fromSubscriberCh <- *req
// Write loop
go func() {
for {
pub := <-ch
if b.maliciousPercent > 0 {
if b.maliciousPercent > 100 {
continue
} else {
pub = b.alterPublication(&pub)
}
}
pub.MAC = common.CreatePublicationMAC(&pub, b.subscribers[id].key)
// fmt.Printf("Send Publication %v, Publisher %v, Broker %v to Subscriber %v.\n", pub.PublicationID, pub.PublisherID, pub.BrokerID, id)
err := stream.Send(&pub)
if err != nil {
b.removeToSubChannel(id)
break
}
}
}()
// Read loop
for {
req, err := stream.Recv()
if err == io.EOF {
b.removeToSubChannel(id)
return err
} else if err != nil {
b.removeToSubChannel(id)
return err
}
// Check MAC
if common.CheckSubscriptionMAC(req, req.MAC, subscriber.key) == false {
//fmt.Printf("***BAD MAC: Subscribe*** %v\n", *req)
continue
}
b.fromSubscriberCh <- *req
}
return nil
}
// connectToBroker connects to a single broker.
// It takes as input the remote broker's ID and address. It also takes as input whether or not
// to be malicous to this remote broker in BRB publications and chain publications.
func (b *Broker) connectToBroker(brokerID uint64, brokerAddr string, brbMalicious bool, chainMalicious bool) {
fmt.Printf("Trying to connect to %v\n", brokerAddr)
var opts []grpc.DialOption
opts = append(opts, grpc.WithInsecure(), grpc.WithBlock())
// Create a gRPC connection
conn, err := grpc.Dial(brokerAddr, opts...)
if err != nil {
fmt.Printf("Error while connecting to server: %v\n", err)
return
}
defer conn.Close()
client := pb.NewInterBrokerClient(conn)
toEchoCh, toReadyCh, toChainCh := b.addBrokerChannels(brokerID)
// Write loop.
for {
select {
case pub := <-toEchoCh:
if brbMalicious {
if b.maliciousPercent > 100 {
continue
} else {
pub = b.alterPublication(&pub)
}
}
pub.MAC = common.CreatePublicationMAC(&pub, b.remoteBrokers[brokerID].key)
_, err := client.Echo(context.Background(), &pub)
if err != nil {
}
case pub := <-toReadyCh:
if brbMalicious {
if b.maliciousPercent > 100 {
continue
} else {
pub = b.alterPublication(&pub)
}
}
pub.MAC = common.CreatePublicationMAC(&pub, b.remoteBrokers[brokerID].key)
_, err := client.Ready(context.Background(), &pub)
if err != nil {
}
case pub := <-toChainCh:
if chainMalicious {
if b.maliciousPercent > 100 {
continue
} else {
pub = b.alterPublication(&pub)
}
}
pub.MAC = common.CreatePublicationMAC(&pub, b.remoteBrokers[brokerID].key)
for sent := false; sent == false; {
resp, err := client.Chain(context.Background(), &pub)
if err != nil {
sent = false
} else if resp.Status == pb.ChainResponse_WAIT {
b.setBusy()
time.Sleep(100 * time.Microsecond)
sent = false
} else {
sent = true
}
}
}
}
}