NetworkCaptureLogger: PCAP support added

Log TCP/UDP read/write with fake packet.

Source/Core/Common/Network.cpp

@@ -6,6 +6,15 @@
 
 #include <algorithm>
 #include <cctype>
+#include <string_view>
+
+#ifndef _WIN32
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#else
+#include <WinSock2.h>
+#endif
 
 #include <fmt/format.h>
 
@@ -72,4 +81,110 @@ std::optional<MACAddress> StringToMacAddress(std::string_view mac_string)
 
   return std::make_optional(mac);
 }
+
+EthernetHeader::EthernetHeader() = default;
+
+EthernetHeader::EthernetHeader(u16 ether_type)
+{
+  ethertype = htons(ether_type);
+}
+
+u16 EthernetHeader::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+IPv4Header::IPv4Header() = default;
+
+IPv4Header::IPv4Header(u16 data_size, u8 ip_proto, const sockaddr_in& from, const sockaddr_in& to)
+{
+  version_ihl = 0x45;
+  total_len = htons(Size() + data_size);
+  flags_fragment_offset = htons(0x4000);
+  ttl = 0x40;
+  protocol = ip_proto;
+  std::memcpy(&source_addr, &from.sin_addr, IPV4_ADDR_LEN);
+  std::memcpy(&destination_addr, &to.sin_addr, IPV4_ADDR_LEN);
+
+  header_checksum = htons(ComputeNetworkChecksum(this, Size()));
+}
+
+u16 IPv4Header::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+TCPHeader::TCPHeader() = default;
+
+TCPHeader::TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, const u8* data,
+                     u16 length)
+{
+  std::memcpy(&source_port, &from.sin_port, 2);
+  std::memcpy(&destination_port, &to.sin_port, 2);
+  sequence_number = htonl(seq);
+
+  // TODO: Write flags
+  // Write data offset
+  std::memset(&properties, 0x50, 1);
+
+  window_size = 0xFFFF;
+
+  // Compute the TCP checksum with its pseudo header
+  const u32 source_addr = ntohl(from.sin_addr.s_addr);
+  const u32 destination_addr = ntohl(to.sin_addr.s_addr);
+  const u32 initial_value = (source_addr >> 16) + (source_addr & 0xFFFF) +
+                            (destination_addr >> 16) + (destination_addr & 0xFFFF) + IPProto() +
+                            Size() + length;
+  u32 tcp_checksum = ComputeNetworkChecksum(this, Size(), initial_value);
+  tcp_checksum += ComputeNetworkChecksum(data, length);
+  while (tcp_checksum > 0xFFFF)
+    tcp_checksum = (tcp_checksum >> 16) + (tcp_checksum & 0xFFFF);
+  checksum = htons(static_cast<u16>(tcp_checksum));
+}
+
+u16 TCPHeader::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+u8 TCPHeader::IPProto() const
+{
+  return static_cast<u8>(IPPROTO_TCP);
+}
+
+UDPHeader::UDPHeader() = default;
+
+UDPHeader::UDPHeader(const sockaddr_in& from, const sockaddr_in& to, u16 data_length)
+{
+  std::memcpy(&source_port, &from.sin_port, 2);
+  std::memcpy(&destination_port, &to.sin_port, 2);
+  length = htons(Size() + data_length);
+}
+
+u16 UDPHeader::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+u8 UDPHeader::IPProto() const
+{
+  return static_cast<u8>(IPPROTO_UDP);
+}
+
+// Compute the network checksum with a 32-bit accumulator using the
+// "Normal" order, see RFC 1071 for more details.
+u16 ComputeNetworkChecksum(const void* data, u16 length, u32 initial_value)
+{
+  u32 checksum = initial_value;
+  std::size_t index = 0;
+  const std::string_view data_view{reinterpret_cast<const char*>(data), length};
+  for (u8 b : data_view)
+  {
+    const bool is_hi = index++ % 2 == 0;
+    checksum += is_hi ? b << 8 : b;
+  }
+  while (checksum > 0xFFFF)
+    checksum = (checksum >> 16) + (checksum & 0xFFFF);
+  return ~static_cast<u16>(checksum);
+}
 }  // namespace Common