privval: Add IPCPV and fix SocketPV (#2568)

Ref: #2563

I added IPC as an unencrypted alternative to SocketPV.

Besides I fixed the following aspects of SocketPV:

Added locking since we are operating on a single socket
The connection deadline is extended every time a successful packet exchange happens; otherwise the connection would always die permanently x seconds after the connection was established.
Added a ping/heartbeat mechanism to keep the connection alive; native TCP keepalives do not work in this use-case


* Extend the SecureConn socket to extend its deadline
* Add locking & ping/heartbeat packets to SocketPV
* Implement IPC PV and abstract socket signing
* Refactored IPC and SocketPV
* Implement @melekes comments
* Fixes to rebase

privval/ipc_test.go

@@ -0,0 +1,147 @@
+package privval
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/log"
+	"github.com/tendermint/tendermint/types"
+)
+
+func TestIPCPVVote(t *testing.T) {
+	var (
+		chainID = cmn.RandStr(12)
+		sc, rs  = testSetupIPCSocketPair(t, chainID, types.NewMockPV())
+
+		ts    = time.Now()
+		vType = types.PrecommitType
+		want  = &types.Vote{Timestamp: ts, Type: vType}
+		have  = &types.Vote{Timestamp: ts, Type: vType}
+	)
+	defer sc.Stop()
+	defer rs.Stop()
+
+	require.NoError(t, rs.privVal.SignVote(chainID, want))
+	require.NoError(t, sc.SignVote(chainID, have))
+	assert.Equal(t, want.Signature, have.Signature)
+}
+
+func TestIPCPVVoteResetDeadline(t *testing.T) {
+	var (
+		chainID = cmn.RandStr(12)
+		sc, rs  = testSetupIPCSocketPair(t, chainID, types.NewMockPV())
+
+		ts    = time.Now()
+		vType = types.PrecommitType
+		want  = &types.Vote{Timestamp: ts, Type: vType}
+		have  = &types.Vote{Timestamp: ts, Type: vType}
+	)
+	defer sc.Stop()
+	defer rs.Stop()
+
+	time.Sleep(3 * time.Millisecond)
+
+	require.NoError(t, rs.privVal.SignVote(chainID, want))
+	require.NoError(t, sc.SignVote(chainID, have))
+	assert.Equal(t, want.Signature, have.Signature)
+
+	// This would exceed the deadline if it was not extended by the previous message
+	time.Sleep(3 * time.Millisecond)
+
+	require.NoError(t, rs.privVal.SignVote(chainID, want))
+	require.NoError(t, sc.SignVote(chainID, have))
+	assert.Equal(t, want.Signature, have.Signature)
+}
+
+func TestIPCPVVoteKeepalive(t *testing.T) {
+	var (
+		chainID = cmn.RandStr(12)
+		sc, rs  = testSetupIPCSocketPair(t, chainID, types.NewMockPV())
+
+		ts    = time.Now()
+		vType = types.PrecommitType
+		want  = &types.Vote{Timestamp: ts, Type: vType}
+		have  = &types.Vote{Timestamp: ts, Type: vType}
+	)
+	defer sc.Stop()
+	defer rs.Stop()
+
+	time.Sleep(10 * time.Millisecond)
+
+	require.NoError(t, rs.privVal.SignVote(chainID, want))
+	require.NoError(t, sc.SignVote(chainID, have))
+	assert.Equal(t, want.Signature, have.Signature)
+}
+
+func testSetupIPCSocketPair(
+	t *testing.T,
+	chainID string,
+	privValidator types.PrivValidator,
+) (*IPCVal, *IPCRemoteSigner) {
+	addr, err := testUnixAddr()
+	require.NoError(t, err)
+
+	var (
+		logger  = log.TestingLogger()
+		privVal = privValidator
+		readyc  = make(chan struct{})
+		rs      = NewIPCRemoteSigner(
+			logger,
+			chainID,
+			addr,
+			privVal,
+		)
+		sc = NewIPCVal(
+			logger,
+			addr,
+		)
+	)
+
+	IPCValConnTimeout(5 * time.Millisecond)(sc)
+	IPCValHeartbeat(time.Millisecond)(sc)
+
+	IPCRemoteSignerConnDeadline(time.Millisecond * 5)(rs)
+
+	testStartIPCRemoteSigner(t, readyc, rs)
+
+	<-readyc
+
+	require.NoError(t, sc.Start())
+	assert.True(t, sc.IsRunning())
+
+	return sc, rs
+}
+
+func testStartIPCRemoteSigner(t *testing.T, readyc chan struct{}, rs *IPCRemoteSigner) {
+	go func(rs *IPCRemoteSigner) {
+		require.NoError(t, rs.Start())
+		assert.True(t, rs.IsRunning())
+
+		readyc <- struct{}{}
+	}(rs)
+}
+
+func testUnixAddr() (string, error) {
+	f, err := ioutil.TempFile("/tmp", "nettest")
+	if err != nil {
+		return "", err
+	}
+
+	addr := f.Name()
+	err = f.Close()
+	if err != nil {
+		return "", err
+	}
+	err = os.Remove(addr)
+	if err != nil {
+		return "", err
+	}
+
+	return addr, nil
+}