Common: Add a PCAP writer module

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);
+}