NetDriver.cpp

/**
 * Copyright (C) ARM Limited 2013-2014. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

// Define to get format macros from inttypes.h
#define __STDC_FORMAT_MACROS

#include "NetDriver.h"

#include <inttypes.h>

#include "Logging.h"
#include "SessionData.h"

class NetCounter : public DriverCounter {
public:
	NetCounter(DriverCounter *next, char *const name, int64_t *const value);
	~NetCounter();

	int64_t read();

private:
	int64_t *const mValue;
	int64_t mPrev;

	// Intentionally unimplemented
	NetCounter(const NetCounter &);
	NetCounter &operator=(const NetCounter &);
};

NetCounter::NetCounter(DriverCounter *next, char *const name, int64_t *const value) : DriverCounter(next, name), mValue(value), mPrev(0) {
}

NetCounter::~NetCounter() {
}

int64_t NetCounter::read() {
	int64_t result = *mValue - mPrev;
	mPrev = *mValue;
	return result;
}

NetDriver::NetDriver() : mBuf(), mReceiveBytes(0), mTransmitBytes(0) {
}

NetDriver::~NetDriver() {
}

void NetDriver::readEvents(mxml_node_t *const) {
	// Only for use with perf
	if (!gSessionData->perf.isSetup()) {
		return;
	}

	setCounters(new NetCounter(getCounters(), strdup("Linux_net_rx"), &mReceiveBytes));
	setCounters(new NetCounter(getCounters(), strdup("Linux_net_tx"), &mTransmitBytes));
}

bool NetDriver::doRead() {
	if (!countersEnabled()) {
		return true;
	}

	if (!mBuf.read("/proc/net/dev")) {
		return false;
	}

	// Skip the header
	char *key;
	if (((key = strchr(mBuf.getBuf(), '\n')) == NULL) ||
			((key = strchr(key + 1, '\n')) == NULL)) {
		return false;
	}
	key = key + 1;

	mReceiveBytes = 0;
	mTransmitBytes = 0;

	char *colon;
	while ((colon = strchr(key, ':')) != NULL) {
		char *end = strchr(colon + 1, '\n');
		if (end != NULL) {
			*end = '\0';
		}
		*colon = '\0';

		int64_t receiveBytes;
		int64_t transmitBytes;
		const int count = sscanf(colon + 1, " %" SCNu64 " %*u %*u %*u %*u %*u %*u %*u %" SCNu64, &receiveBytes, &transmitBytes);
		if (count != 2) {
			return false;
		}
		mReceiveBytes += receiveBytes;
		mTransmitBytes += transmitBytes;

		if (end == NULL) {
			break;
		}
		key = end + 1;
	}

	return true;
}

void NetDriver::start() {
	if (!doRead()) {
		logg->logError(__FILE__, __LINE__, "Unable to read network stats");
		handleException();
	}
	// Initialize previous values
	for (DriverCounter *counter = getCounters(); counter != NULL; counter = counter->getNext()) {
		if (!counter->isEnabled()) {
			continue;
		}
		counter->read();
	}
}

void NetDriver::read(Buffer *const buffer) {
	if (!doRead()) {
		logg->logError(__FILE__, __LINE__, "Unable to read network stats");
		handleException();
	}
	super::read(buffer);
}