Update buffer allocation strategy and maximum buffer size when using TCP as transport

src/system/SystemConfig.h

@@ -358,6 +358,26 @@
 #define CHIP_SYSTEM_CONFIG_PACKETBUFFER_POOL_SIZE 15
 #endif /* CHIP_SYSTEM_CONFIG_PACKETBUFFER_POOL_SIZE */
 
+/**
+ *  @def CHIP_CONFIG_TCP_SUPPORT_CLIENT
+ *
+ *  @brief
+ *      Indicates whether the current node supports TCP Client
+ */
+#ifndef CHIP_CONFIG_TCP_SUPPORT_CLIENT
+#define CHIP_CONFIG_TCP_SUPPORT_CLIENT 0
+#endif /* CHIP_CONFIG_TCP_SUPPORT_CLIENT */
+
+/**
+ *  @def CHIP_CONFIG_TCP_SUPPORT_SERVER
+ *
+ *  @brief
+ *      Indicates whether the current node supports TCP Server
+ */
+#ifndef CHIP_CONFIG_TCP_SUPPORT_SERVER
+#define CHIP_CONFIG_TCP_SUPPORT_SERVER 0
+#endif /* CHIP_CONFIG_TCP_SUPPORT_SERVER */
+
 /**
  *  @def CHIP_SYSTEM_CONFIG_PACKETBUFFER_LWIP_PBUF_RAM
  *

src/transport/raw/MessageHeader.h

@@ -42,38 +42,49 @@
 
 namespace chip {
 
+static constexpr size_t kMaxTagLen = 16;
+
 namespace detail {
 // Figure out the max size of a packet we can allocate, including all headers.
-static constexpr size_t kMaxIPPacketSizeBytes       = 1280;
+static constexpr size_t kMaxUdpIPPacketSizeBytes       = 1280;
+static constexpr size_t kMaxTcpIPPacketSizeBytes       = 12800;
 static constexpr size_t kMaxUDPAndIPHeaderSizeBytes = 48;
 
-static_assert(kMaxIPPacketSizeBytes >= kMaxUDPAndIPHeaderSizeBytes + CHIP_SYSTEM_HEADER_RESERVE_SIZE,
+static_assert(kMaxUdpIPPacketSizeBytes >= kMaxUDPAndIPHeaderSizeBytes + CHIP_SYSTEM_HEADER_RESERVE_SIZE,
               "Matter headers and IP headers must fit in an MTU.");
 
 // Max space we have for our Application Payload and MIC, per spec.
 static constexpr size_t kMaxPerSpecApplicationPayloadAndMICSizeBytes =
-    kMaxIPPacketSizeBytes - kMaxUDPAndIPHeaderSizeBytes - CHIP_SYSTEM_HEADER_RESERVE_SIZE;
+    kMaxUdpIPPacketSizeBytes - kMaxUDPAndIPHeaderSizeBytes - CHIP_SYSTEM_HEADER_RESERVE_SIZE;
 
 // Max space we have for our Application Payload and MIC in our actual packet
 // buffers.  This is the size _excluding_ the header reserve.
 static constexpr size_t kMaxPacketBufferApplicationPayloadAndMICSizeBytes = System::PacketBuffer::kMaxSize;
 
-static constexpr size_t kMaxApplicationPayloadAndMICSizeBytes =
+static constexpr size_t kMaxApplicationUdpPayloadAndMICSizeBytes =
     min(kMaxPerSpecApplicationPayloadAndMICSizeBytes, kMaxPacketBufferApplicationPayloadAndMICSizeBytes);
 
-} // namespace detail
+static constexpr size_t kMaxApplicationTcpPayloadAndMICSizeBytes =
+    kMaxTcpIPPacketSizeBytes - CHIP_SYSTEM_HEADER_RESERVE_SIZE;
 
-static constexpr size_t kMaxTagLen = 16;
-
-static_assert(detail::kMaxApplicationPayloadAndMICSizeBytes > kMaxTagLen, "Need to be able to fit our tag in a message");
+static_assert(detail::kMaxApplicationUdpPayloadAndMICSizeBytes > kMaxTagLen, "Need to be able to fit our tag in a message");
+static_assert(detail::kMaxApplicationTcpPayloadAndMICSizeBytes > kMaxTagLen, "Need to be able to fit our tag in a message");
 
 // This is somewhat of an under-estimate, because in practice any time we have a
 // tag we will not have source/destination node IDs, but above we are including
 // those in the header sizes.
-static constexpr size_t kMaxAppMessageLen = detail::kMaxApplicationPayloadAndMICSizeBytes - kMaxTagLen;
+static constexpr size_t kMaxUdpAppMessageLen = kMaxApplicationUdpPayloadAndMICSizeBytes - kMaxTagLen;
+static constexpr size_t kMaxTcpAppMessageLen = kMaxApplicationTcpPayloadAndMICSizeBytes - kMaxTagLen;
+} // namespace detail
 
 static constexpr uint16_t kMsgUnicastSessionIdUnsecured = 0x0000;
 
+#if CHIP_CONFIG_TCP_SUPPORT_SERVER || CHIP_CONFIG_TCP_SUPPORT_CLIENT
+static constexpr size_t kMaxAppMessageLen = detail::kMaxTcpAppMessageLen;
+#else
+static constexpr size_t kMaxAppMessageLen = detail::kMaxUdpAppMessageLen;
+#endif
+
 typedef int PacketHeaderFlags;
 
 namespace Header {