Inial population of repository.

simulator/sim_lib/vtap_linux.cpp

@@ -0,0 +1,123 @@
+#include "vtap_linux.h"
+
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+#include "utils.h"
+
+const size_t cMaxPacketSize = 2048; // We don't support jumbo packets for now at least
+
+const uint8_t cClosing = 1;
+
+TapAdapter_c::TapAdapter_c() :
+	mDevice(-1),
+	mSignalPipeSend(-1),
+	mSignalPipeRcv(-1)
+{
+	int Pipe[2];
+	if (pipe(Pipe) != 0) throw Generic_x() << "Can't create pipe with error code: " << DecPrinter(errno);
+	mSignalPipeSend = Pipe[1];
+	mSignalPipeRcv = Pipe[0];
+}
+
+TapAdapter_c::~TapAdapter_c() {
+	Close();
+	if (mSignalPipeSend != -1) {
+		if (close(mSignalPipeSend) == -1) std::cout << "TAP Can't close pipe with error code: " << DecPrinter(errno) << std::endl;
+	}
+	if (mSignalPipeRcv != -1) {
+		if (close(mSignalPipeRcv) == -1) std::cout << "TAP Can't close pipe with error code: " << DecPrinter(errno) << std::endl;
+	}
+}
+
+TapAdapter_c::TapAdapter_c(TapAdapter_c &&aAdapter) {
+	mDevice = aAdapter.mDevice;
+	mName = aAdapter.mName;
+}
+
+void TapAdapter_c::CancelRead() {
+	int RetVal = write(mSignalPipeSend, &cClosing, sizeof(cClosing));
+	if (RetVal < 0) {
+		throw Generic_x() << "Error writing to TAP device with error code: " << DecPrinter(errno);
+	} else if (RetVal != sizeof(cClosing)) {
+		throw Generic_x() << "Incomplete packet write to TAP device";
+	}
+}
+
+
+void TapAdapter_c::Close() {
+	if (mDevice != -1) {
+		CancelRead();
+		if (close(mDevice) == -1) {
+			throw Generic_x() << "Error closing TAP file handle with error code: " << DecPrinter(errno);
+		}
+		mDevice = -1;
+	}
+}
+
+void TapAdapter_c::Open() {
+	Close();
+
+	// open the clone device
+	const char *CloneDevName = "/dev/net/tun";
+	int CloneDev = open(CloneDevName, O_RDWR);
+	if (CloneDev < 0) throw Generic_x() << "Can't open " << CloneDevName << " with error code: " << DecPrinter(errno) << ". Maybe tun devices aren't enabled?";
+
+	// Create request to create/open TAP device
+	struct ifreq IfRequest;
+	memset(&IfRequest, 0, sizeof(IfRequest));
+	IfRequest.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_UP;
+	if (mName.length() > 0) {
+		if (mName.length() >= IFNAMSIZ) throw Generic_x() << "TAP device name " << mName << " is too long";
+		strncpy(IfRequest.ifr_name, &mName[0], mName.length());
+	}
+	int RetVal = ioctl(CloneDev, TUNSETIFF, (void *) &IfRequest);
+	if (RetVal < 0 ) {
+		close(CloneDev);
+		throw Generic_x() << "Error creating TAP device " << mName << " with error code: " << DecPrinter(errno);
+	}
+
+	if (mName.length() == 0) mName = IfRequest.ifr_name;
+	
+	mDevice = CloneDev;
+//	std::cout << "Using file handle: " << DecPrinter(mDevice) << std::endl;
+}
+
+std::vector<uint8_t> TapAdapter_c::BlockingReceive() {
+	fd_set DescSet;
+
+	FD_ZERO(&DescSet);
+	FD_SET(mSignalPipeRcv, &DescSet);
+	FD_SET(mDevice, &DescSet);
+
+	int RetVal = TEMP_FAILURE_RETRY(select(std::max(mSignalPipeRcv, mDevice)+1, &DescSet, nullptr, nullptr, nullptr));
+	if (RetVal == -1) throw Generic_x() << "Error in select call with error code: " << DecPrinter(errno);
+	if (!FD_ISSET(mDevice, &DescSet)) {
+		return std::vector<uint8_t>(); // If operation is cancelled, return an empty array
+	}
+	
+	std::vector<uint8_t> Buffer(cMaxPacketSize);
+	int BytesRead =  TEMP_FAILURE_RETRY(read(mDevice,&Buffer[0],Buffer.size()));
+	if (BytesRead < 0) {
+		throw Generic_x() << "Error reading from TAP device with error code: " << DecPrinter(errno);
+	}
+	Buffer.resize(BytesRead);
+	return Buffer;
+}
+
+void TapAdapter_c::Send(std::vector<uint8_t> aPacket) {
+	if (mDevice == -1) {
+		throw Generic_x() << "TAP Device isn't opened";
+	}
+	int RetVal = write(mDevice, &aPacket[0], aPacket.size());
+	if (RetVal < 0) {
+		throw Generic_x() << "Error writing to TAP device with error code: " << DecPrinter(errno);
+	} else if (RetVal != int(aPacket.size())) {
+		throw Generic_x() << "Incomplete packet write to TAP device";
+	}
+}
+