From ce74752e9171ce21efa226e9435d66441a1b9a1c Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Mon, 21 Apr 2014 02:43:45 +0200
Subject: [PATCH] Common: Add a PCAP writer module

---
 Source/Core/Common/CMakeLists.txt         |  1 +
 Source/Core/Common/Common.vcxproj         |  2 +
 Source/Core/Common/Common.vcxproj.filters |  2 +
 Source/Core/Common/PcapFile.cpp           | 66 +++++++++++++++++++++++
 Source/Core/Common/PcapFile.h             | 44 +++++++++++++++
 5 files changed, 115 insertions(+)
 create mode 100644 Source/Core/Common/PcapFile.cpp
 create mode 100644 Source/Core/Common/PcapFile.h

diff --git a/Source/Core/Common/CMakeLists.txt b/Source/Core/Common/CMakeLists.txt
index 90385653f7..a9535a1799 100644
--- a/Source/Core/Common/CMakeLists.txt
+++ b/Source/Core/Common/CMakeLists.txt
@@ -14,6 +14,7 @@ set(SRCS	BreakPoints.cpp
 			MsgHandler.cpp
 			NandPaths.cpp
 			Network.cpp
+			PcapFile.cpp
 			SettingsHandler.cpp
 			SDCardUtil.cpp
 			StringUtil.cpp
diff --git a/Source/Core/Common/Common.vcxproj b/Source/Core/Common/Common.vcxproj
index 00bcb07c80..87c14c321c 100644
--- a/Source/Core/Common/Common.vcxproj
+++ b/Source/Core/Common/Common.vcxproj
@@ -78,6 +78,7 @@
     <ClInclude Include="MsgHandler.h" />
     <ClInclude Include="NandPaths.h" />
     <ClInclude Include="Network.h" />
+    <ClInclude Include="PcapFile.h" />
     <ClInclude Include="SDCardUtil.h" />
     <ClInclude Include="SettingsHandler.h" />
     <ClInclude Include="stdafx.h" />
@@ -114,6 +115,7 @@
     <ClCompile Include="MsgHandler.cpp" />
     <ClCompile Include="NandPaths.cpp" />
     <ClCompile Include="Network.cpp" />
+    <ClCompile Include="PcapFile.cpp" />
     <ClCompile Include="SDCardUtil.cpp" />
     <ClCompile Include="SettingsHandler.cpp" />
     <ClCompile Include="stdafx.cpp">
diff --git a/Source/Core/Common/Common.vcxproj.filters b/Source/Core/Common/Common.vcxproj.filters
index 5f9b211828..bca6b0c68e 100644
--- a/Source/Core/Common/Common.vcxproj.filters
+++ b/Source/Core/Common/Common.vcxproj.filters
@@ -39,6 +39,7 @@
     <ClInclude Include="MsgHandler.h" />
     <ClInclude Include="NandPaths.h" />
     <ClInclude Include="Network.h" />
+    <ClInclude Include="PcapFile.h" />
     <ClInclude Include="SDCardUtil.h" />
     <ClInclude Include="SettingsHandler.h" />
     <ClInclude Include="StdConditionVariable.h" />
@@ -86,6 +87,7 @@
     <ClCompile Include="MsgHandler.cpp" />
     <ClCompile Include="NandPaths.cpp" />
     <ClCompile Include="Network.cpp" />
+    <ClCompile Include="PcapFile.cpp" />
     <ClCompile Include="SDCardUtil.cpp" />
     <ClCompile Include="SettingsHandler.cpp" />
     <ClCompile Include="StringUtil.cpp" />
diff --git a/Source/Core/Common/PcapFile.cpp b/Source/Core/Common/PcapFile.cpp
new file mode 100644
index 0000000000..9a28daca2d
--- /dev/null
+++ b/Source/Core/Common/PcapFile.cpp
@@ -0,0 +1,66 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <chrono>
+
+#include "Common/CommonTypes.h"
+#include "Common/FileUtil.h"
+#include "Common/PcapFile.h"
+
+namespace {
+
+const u32 PCAP_MAGIC = 0xa1b2c3d4;
+const u16 PCAP_VERSION_MAJOR = 2;
+const u16 PCAP_VERSION_MINOR = 4;
+const u32 PCAP_CAPTURE_LENGTH = 65535;
+
+// TODO(delroth): Make this configurable at PCAP creation time?
+const u32 PCAP_DATA_LINK_TYPE = 147;  // Reserved for internal use.
+
+// Designed to be directly written into the PCAP file. The PCAP format is
+// endian independent, so this works just fine.
+#pragma pack(push, 1)
+struct PCAPHeader
+{
+	u32 magic_number;
+	u16 version_major;
+	u16 version_minor;
+	s32 tz_offset;       // Offset in seconds from the GMT timezone.
+	u32 ts_accuracy;     // In practice, 0.
+	u32 capture_length;  // Size at which we truncate packets.
+	u32 data_link_type;
+};
+
+struct PCAPRecordHeader
+{
+	u32 ts_sec;
+	u32 ts_usec;
+	u32 size_in_file;  // Size after eventual truncation.
+	u32 real_size;     // Size before eventual truncation.
+};
+#pragma pack(pop)
+
+}  // namespace
+
+void PCAP::AddHeader()
+{
+	PCAPHeader hdr = {
+		PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR,
+		0, 0, PCAP_CAPTURE_LENGTH, PCAP_DATA_LINK_TYPE
+	};
+	m_fp->WriteBytes(&hdr, sizeof (hdr));
+}
+
+void PCAP::AddPacket(const u8* bytes, size_t size)
+{
+	std::chrono::system_clock::time_point now(std::chrono::system_clock::now());
+	auto ts = now.time_since_epoch();
+	PCAPRecordHeader rec_hdr = {
+		(u32)std::chrono::duration_cast<std::chrono::seconds>(ts).count(),
+		(u32)(std::chrono::duration_cast<std::chrono::microseconds>(ts).count() % 1000000),
+		(u32)size, (u32)size
+	};
+	m_fp->WriteBytes(&rec_hdr, sizeof (rec_hdr));
+	m_fp->WriteBytes(bytes, size);
+}
diff --git a/Source/Core/Common/PcapFile.h b/Source/Core/Common/PcapFile.h
new file mode 100644
index 0000000000..f3bc98d23c
--- /dev/null
+++ b/Source/Core/Common/PcapFile.h
@@ -0,0 +1,44 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+// PCAP is a standard file format for network capture files. This also extends
+// to any capture of packetized intercommunication data. This file provides a
+// class called PCAP which is a very light wrapper around the file format,
+// allowing only creating a new PCAP capture file and appending packets to it.
+//
+// Example use:
+//   PCAP pcap(new IOFile("test.pcap", "wb"));
+//   pcap.AddPacket(pkt);  // pkt is automatically casted to u8*
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+
+#include "Common/CommonTypes.h"
+#include "Common/FileUtil.h"
+
+class PCAP final : public NonCopyable
+{
+public:
+	// Takes ownership of the file object. Assumes the file object is already
+	// opened in write mode.
+	explicit PCAP(File::IOFile* fp) : m_fp(fp)
+	{
+		AddHeader();
+	}
+
+	template <typename T>
+	void AddPacket(const T& obj)
+	{
+		AddPacket(reinterpret_cast<const u8*>(&obj), sizeof (obj));
+	}
+
+	void AddPacket(const u8* bytes, size_t size);
+
+private:
+	void AddHeader();
+
+	std::unique_ptr<File::IOFile> m_fp;
+};