Adding AccurateECN flag to TCP struct (#1869)

Author: turtleman123

Packet++/header/TcpLayer.h

@@ -28,7 +28,10 @@ namespace pcpp
 		/// Acknowledgment number
 		uint32_t ackNumber;
 #if (BYTE_ORDER == LITTLE_ENDIAN)
-		uint16_t reserved : 4;
+		/// Accurate ECN flag
+		uint16_t accurateEcnFlag : 1;
+		/// Reserved bits
+		uint16_t reserved : 3;
 		/// Specifies the size of the TCP header in 32-bit words
 		uint16_t dataOffset : 4;
 		/// FIN flag
@@ -51,7 +54,9 @@ namespace pcpp
 		/// Specifies the size of the TCP header in 32-bit words
 		uint16_t dataOffset : 4;
 		/// Reserved
-		uint16_t reserved : 4;
+		uint16_t reserved : 3;
+		/// Accurate ECN flag
+		uint16_t accurateEcnFlag : 1;
 		/// CWR flag
 		uint16_t cwrFlag : 1;
 		/// ECE flag

Tests/Packet++Test/PacketExamples/TcpPacketNoOptionsAccEcn.dat

@@ -0,0 +1 @@
+6cf049b2de6e30469a23fbfa080045000115a80040003c06ecd4d4c7ca450a0000010050ebe4beab364af9ffb58e51182d3c4c030000485454502f312e3120333031204d6f766564205065726d616e656e746c790d0a5365727665723a20416b616d616947486f73740d0a436f6e74656e742d4c656e6774683a20300d0a4c6f636174696f6e3a202f686f6d652f302c373334302c4c2d382c30302e68746d6c0d0a43616368652d436f6e74726f6c3a206d61782d6167653d300d0a457870697265733a204672692c2032362053657020323031342032323a32333a323420474d540d0a446174653a204672692c2032362053657020323031342032323a32333a323420474d540d0a436f6e6e656374696f6e3a206b6565702d616c6976650d0a0d0a

Tests/Packet++Test/PacketExamples/TcpPacketNoOptionsAccEcn.pcap

@@ -33,6 +33,7 @@ PTF_TEST_CASE(IPv6ExtensionsTest);
 // Implemented in TcpTests.cpp
 PTF_TEST_CASE(TcpPacketNoOptionsParsing);
 PTF_TEST_CASE(TcpPacketWithOptionsParsing);
+PTF_TEST_CASE(TcpPacketWithAccurateEcnParsing);
 PTF_TEST_CASE(TcpPacketWithOptionsParsing2);
 PTF_TEST_CASE(TcpMalformedPacketParsing);
 PTF_TEST_CASE(TcpPacketCreation);

Tests/Packet++Test/TestDefinition.h

@@ -46,6 +46,7 @@ PTF_TEST_CASE(TcpPacketNoOptionsParsing)
 	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->rstFlag, 0);
 	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->eceFlag, 0);
 	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->reserved, 0);
+	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->accurateEcnFlag, 0);
 
 	// TCP options
 	PTF_ASSERT_EQUAL(tcpLayer->getTcpOptionCount(), 0);
@@ -63,6 +64,23 @@ PTF_TEST_CASE(TcpPacketNoOptionsParsing)
 	PTF_ASSERT_EQUAL(afterTcpLayer->getProtocol(), pcpp::HTTPResponse, enum);
 }  // TcpPacketNoOptionsParsing
 
+PTF_TEST_CASE(TcpPacketWithAccurateEcnParsing)
+{
+	timeval time;
+	gettimeofday(&time, nullptr);
+
+	READ_FILE_AND_CREATE_PACKET(1, "PacketExamples/TcpPacketNoOptionsAccEcn.dat");
+
+	pcpp::Packet TcpPacketWithAccurateEcn(&rawPacket1);
+	PTF_ASSERT_TRUE(TcpPacketWithAccurateEcn.isPacketOfType(pcpp::TCP));
+
+	pcpp::TcpLayer* tcpLayer = TcpPacketWithAccurateEcn.getLayerOfType<pcpp::TcpLayer>();
+	PTF_ASSERT_NOT_NULL(tcpLayer);
+
+	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->reserved, 0);
+	PTF_ASSERT_EQUAL(tcpLayer->getTcpHeader()->accurateEcnFlag, 1);
+}  // TcpPacketWithAccurateEcnParsing
+
 PTF_TEST_CASE(TcpPacketWithOptionsParsing)
 {
 	timeval time;

Tests/Packet++Test/Tests/TcpTests.cpp

@@ -136,6 +136,7 @@ int main(int argc, char* argv[])
 	PTF_RUN_TEST(IPv6ExtensionsTest, "ipv6");
 
 	PTF_RUN_TEST(TcpPacketNoOptionsParsing, "tcp");
+	PTF_RUN_TEST(TcpPacketWithAccurateEcnParsing, "tcp");
 	PTF_RUN_TEST(TcpPacketWithOptionsParsing, "tcp");
 	PTF_RUN_TEST(TcpPacketWithOptionsParsing2, "tcp");
 	PTF_RUN_TEST(TcpPacketCreation, "tcp");