fastboot: fix TCP protocol version check.

Currently the TCP handshake fails if the device TCP protocol version
doesn't match the host exactly, but the protocol is supposed to allow
for forwards compatibility by accepting any protocol version >= itself.
That way the other side can potentially lower its protocol to match and
keep going.

This CL fixes the protocol version check and adds corresponding unit
tests.

Bug: http://b/27220700
Change-Id: Ib17f0a55eb910105a27609bc94bf76a30442e92e

1 files changed, 12 insertions, 2 deletions

diff --git a/fastboot/tcp_test.cpp b/fastboot/tcp_test.cpp
index 7d80d76f5..6e867ae85 100644
--- a/fastboot/tcp_test.cpp
+++ b/fastboot/tcp_test.cpp
@@ -42,6 +42,16 @@ TEST(TcpConnectTest, TestSuccess) {
     EXPECT_EQ("", error);
 }
 
+TEST(TcpConnectTest, TestNewerVersionSuccess) {
+    std::unique_ptr<SocketMock> mock(new SocketMock);
+    mock->ExpectSend("FB01");
+    mock->AddReceive("FB99");
+
+    std::string error;
+    EXPECT_NE(nullptr, tcp::internal::Connect(std::move(mock), &error));
+    EXPECT_EQ("", error);
+}
+
 TEST(TcpConnectTest, TestSendFailure) {
     std::unique_ptr<SocketMock> mock(new SocketMock);
     mock->ExpectSendFailure("FB01");
@@ -74,11 +84,11 @@ TEST(TcpConnectTest, TestBadResponseFailure) {
 TEST(TcpConnectTest, TestUnknownVersionFailure) {
     std::unique_ptr<SocketMock> mock(new SocketMock);
     mock->ExpectSend("FB01");
-    mock->AddReceive("FB02");
+    mock->AddReceive("FB00");
 
     std::string error;
     EXPECT_EQ(nullptr, tcp::internal::Connect(std::move(mock), &error));
-    EXPECT_EQ("Unknown TCP protocol version 02 (host version 01)", error);
+    EXPECT_EQ("Unknown TCP protocol version 00 (host version 01)", error);
 }
 
 // Fixture to configure a SocketMock for a successful TCP connection.