[FAB-13805] Unify Step and Submit into a stream

This change set removes Step RPC from the cluster protobuf,
and renames Submit stream to a Step stream, and makes both
transaction forwarding and consensus messages use the
new Step stream.

It also makes both egress Send() and Recv(), have a maximum
timeout (the RPC timeout in the config).
A Send or Recv that is used to send a consensus message,
or send (receive) a transaction (status) will now abort prematurely
in order to protect against any liveness issue on the remote node,
and also to return an answer to clients within a timely manner.

Change-Id: Id942b248212f5c324e12af34fce48f96fdbb6aea
Signed-off-by: yacovm <yacovm@il.ibm.com>

core/comm/util.go

@@ -115,7 +115,7 @@ func noopBinding(_ context.Context, _ []byte) error {
 // ExtractCertificateHashFromContext extracts the hash of the certificate from the given context.
 // If the certificate isn't present, nil is returned
 func ExtractCertificateHashFromContext(ctx context.Context) []byte {
-	rawCert := ExtractCertificateFromContext(ctx)
+	rawCert := ExtractRawCertificateFromContext(ctx)
 	if len(rawCert) == 0 {
 		return nil
 	}
@@ -126,7 +126,7 @@ func ExtractCertificateHashFromContext(ctx context.Context) []byte {
 
 // ExtractCertificateFromContext returns the TLS certificate (if applicable)
 // from the given context of a gRPC stream
-func ExtractCertificateFromContext(ctx context.Context) []byte {
+func ExtractCertificateFromContext(ctx context.Context) *x509.Certificate {
 	pr, extracted := peer.FromContext(ctx)
 	if !extracted {
 		return nil
@@ -145,5 +145,15 @@ func ExtractCertificateFromContext(ctx context.Context) []byte {
 	if len(certs) == 0 {
 		return nil
 	}
-	return certs[0].Raw
+	return certs[0]
+}
+
+// ExtractRawCertificateFromContext returns the raw TLS certificate (if applicable)
+// from the given context of a gRPC stream
+func ExtractRawCertificateFromContext(ctx context.Context) []byte {
+	cert := ExtractCertificateFromContext(ctx)
+	if cert == nil {
+		return nil
+	}
+	return cert.Raw
 }