IdletimerController.cpp - platform/system/netd - Git at Google

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // #define LOG_NDEBUG 0

 /*
  * MODUS OPERANDI
  * --------------
  *
  * IPTABLES command sequence:
  *
  * iptables -F
  *
  * iptables -t raw -F idletimer_PREROUTING
  * iptables -t mangle -F idletimer_POSTROUTING
  *
  *
  * iptables -t raw -N idletimer_PREROUTING
  * iptables -t mangle -N idletimer_POSTROUTING
  *
  * iptables -t raw -D PREROUTING -j idletimer_PREROUTING
  * iptables -t mangle -D POSTROUTING -j idletimer_POSTROUTING
  *
  *
  * iptables -t raw -I PREROUTING -j idletimer_PREROUTING
  * iptables -t mangle -I POSTROUTING -j idletimer_POSTROUTING
  *
  * # For notifications to work the lable name must match the name of a valid interface.
  * # If the label name does match an interface, the rules will be a no-op.
  *
  * iptables -t raw -A idletimer_PREROUTING -i rmnet0 -j IDLETIMER  --timeout 5 --label test-chain --send_nl_msg 1
  * iptables -t mangle -A idletimer_POSTROUTING -o rmnet0 -j IDLETIMER  --timeout 5 --label test-chain --send_nl_msg 1
  *
  * iptables -nxvL -t raw
  * iptables -nxvL -t mangle
  *
  * =================
  *
  * ndc command sequence
  * ------------------
  * ndc idletimer enable
  * ndc idletimer add <iface> <timeout> <class label>
  * ndc idletimer remove <iface> <timeout> <class label>
  *
  * Monitor effect on the iptables chains after each step using:
  *     iptables -nxvL -t raw
  *     iptables -nxvL -t mangle
  *
  * Remember that the timeout value has to be same at the time of the
  * removal.
  *
  * =================
  *
  * Verifying the iptables rule
  * ---------------------------
  * We want to make sure the iptable rules capture every packet. It can be
  * verified with tcpdump. First take a note of the pkts count for the two rules:
  *
  * adb shell iptables -t mangle -L idletimer_mangle_POSTROUTING -v && adb shell iptables -t raw -L idletimer_raw_PREROUTING -v
  *
  * And then, before any network traffics happen on the device, run tcpdump:
  *
  * adb shell tcpdump | tee tcpdump.log
  *
  * After a while run iptables commands again, you could then count the number
  * of incoming and outgoing packets captured by tcpdump, and compare that with
  * the numbers reported by iptables command. There shouldn't be too much
  * difference on these numbers, i.e., with 2000 packets captured it should
  * differ by less than 5.
  *
  * =================
  *
  * Note that currently if the name of the iface is incorrect, iptables
  * will setup rules without checking if it is the name of a valid
  * interface (although no notifications will ever be received).  It is
  * the responsibility of code in Java land to ensure that the interface name
  * is correct. The benefit of this, is that idletimers can be setup on
  * interfaces than come and go.
  *
  * A remove should be called for each add command issued during cleanup, as duplicate
  * entries of the rule may exist and will all have to removed.
  *
  */

 #include <stdlib.h>
 #include <errno.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <fcntl.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <string.h>
 #include <cutils/properties.h>

 #define LOG_TAG "IdletimerController"
 #include <cutils/log.h>
 #include <logwrap/logwrap.h>

 #include "IdletimerController.h"
 #include "NetdConstants.h"

 const char* IdletimerController::LOCAL_RAW_PREROUTING = "idletimer_raw_PREROUTING";
 const char* IdletimerController::LOCAL_MANGLE_POSTROUTING = "idletimer_mangle_POSTROUTING";

 IdletimerController::IdletimerController() {
 }

 IdletimerController::~IdletimerController() {
 }
 /* return 0 or non-zero */
 int IdletimerController::runIpxtablesCmd(int argc, const char **argv) {
     int res;

     res = android_fork_execvp(argc, (char **)argv, NULL, false, false);
     ALOGV("runCmd() res=%d", res);
     return res;
 }

 bool IdletimerController::setupIptablesHooks() {
     return true;
 }

 int IdletimerController::setDefaults() {
   int res;
   const char *cmd1[] = {
       IPTABLES_PATH,
       "-t",
       "raw",
       "-F",
       LOCAL_RAW_PREROUTING
   };
   res = runIpxtablesCmd(ARRAY_SIZE(cmd1), cmd1);

   if (res)
     return res;

   const char *cmd2[] = {
       IPTABLES_PATH,
       "-t",
       "mangle",
       "-F",
       LOCAL_MANGLE_POSTROUTING
   };
   res = runIpxtablesCmd(ARRAY_SIZE(cmd2), cmd2);

   return res;
 }

 int IdletimerController::enableIdletimerControl() {
     int res = setDefaults();
     return res;
 }

 int IdletimerController::disableIdletimerControl() {
     int res = setDefaults();
     return res;
 }

 int IdletimerController::modifyInterfaceIdletimer(IptOp op, const char *iface,
                                                   uint32_t timeout,
                                                   const char *classLabel) {
   int res;
   char timeout_str[11]; //enough to store any 32-bit unsigned decimal

   snprintf(timeout_str, sizeof(timeout_str), "%u", timeout);

   const char *cmd1[] = {
       IPTABLES_PATH,
       "-t",
       "raw",
       (op == IptOpAdd) ? "-A" : "-D",
       LOCAL_RAW_PREROUTING,
       "-i",
       iface,
       "-j",
       "IDLETIMER",
       "--timeout",
       timeout_str,
       "--label",
       classLabel,
       "--send_nl_msg",
       "1"
   };
   res = runIpxtablesCmd(ARRAY_SIZE(cmd1), cmd1);

   if (res)
     return res;

   const char *cmd2[] = {
       IPTABLES_PATH,
       "-t",
       "mangle",
       (op == IptOpAdd) ? "-A" : "-D",
       LOCAL_MANGLE_POSTROUTING,
       "-o",
       iface,
       "-j",
       "IDLETIMER",
       "--timeout",
       timeout_str,
       "--label",
       classLabel,
       "--send_nl_msg",
       "1"
   };
   res = runIpxtablesCmd(ARRAY_SIZE(cmd2), cmd2);

   return res;
 }

 int IdletimerController::addInterfaceIdletimer(const char *iface,
                                                uint32_t timeout,
                                                const char *classLabel) {
   return modifyInterfaceIdletimer(IptOpAdd, iface, timeout, classLabel);
 }

 int IdletimerController::removeInterfaceIdletimer(const char *iface,
                                                   uint32_t timeout,
                                                   const char *classLabel) {
   return modifyInterfaceIdletimer(IptOpDelete, iface, timeout, classLabel);
 }
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// #define LOG_NDEBUG 0

	/*
	* MODUS OPERANDI
	* --------------
	*
	* IPTABLES command sequence:
	*
	* iptables -F
	*
	* iptables -t raw -F idletimer_PREROUTING
	* iptables -t mangle -F idletimer_POSTROUTING
	*
	*
	* iptables -t raw -N idletimer_PREROUTING
	* iptables -t mangle -N idletimer_POSTROUTING
	*
	* iptables -t raw -D PREROUTING -j idletimer_PREROUTING
	* iptables -t mangle -D POSTROUTING -j idletimer_POSTROUTING
	*
	*
	* iptables -t raw -I PREROUTING -j idletimer_PREROUTING
	* iptables -t mangle -I POSTROUTING -j idletimer_POSTROUTING
	*
	* # For notifications to work the lable name must match the name of a valid interface.
	* # If the label name does match an interface, the rules will be a no-op.
	*
	* iptables -t raw -A idletimer_PREROUTING -i rmnet0 -j IDLETIMER --timeout 5 --label test-chain --send_nl_msg 1
	* iptables -t mangle -A idletimer_POSTROUTING -o rmnet0 -j IDLETIMER --timeout 5 --label test-chain --send_nl_msg 1
	*
	* iptables -nxvL -t raw
	* iptables -nxvL -t mangle
	*
	* =================
	*
	* ndc command sequence
	* ------------------
	* ndc idletimer enable
	* ndc idletimer add <iface> <timeout> <class label>
	* ndc idletimer remove <iface> <timeout> <class label>
	*
	* Monitor effect on the iptables chains after each step using:
	* iptables -nxvL -t raw
	* iptables -nxvL -t mangle
	*
	* Remember that the timeout value has to be same at the time of the
	* removal.
	*
	* =================
	*
	* Verifying the iptables rule
	* ---------------------------
	* We want to make sure the iptable rules capture every packet. It can be
	* verified with tcpdump. First take a note of the pkts count for the two rules:
	*
	* adb shell iptables -t mangle -L idletimer_mangle_POSTROUTING -v && adb shell iptables -t raw -L idletimer_raw_PREROUTING -v
	*
	* And then, before any network traffics happen on the device, run tcpdump:
	*
	* adb shell tcpdump \| tee tcpdump.log
	*
	* After a while run iptables commands again, you could then count the number
	* of incoming and outgoing packets captured by tcpdump, and compare that with
	* the numbers reported by iptables command. There shouldn't be too much
	* difference on these numbers, i.e., with 2000 packets captured it should
	* differ by less than 5.
	*
	* =================
	*
	* Note that currently if the name of the iface is incorrect, iptables
	* will setup rules without checking if it is the name of a valid
	* interface (although no notifications will ever be received). It is
	* the responsibility of code in Java land to ensure that the interface name
	* is correct. The benefit of this, is that idletimers can be setup on
	* interfaces than come and go.
	*
	* A remove should be called for each add command issued during cleanup, as duplicate
	* entries of the rule may exist and will all have to removed.
	*
	*/

	#include <stdlib.h>
	#include <errno.h>
	#include <sys/socket.h>
	#include <sys/stat.h>
	#include <sys/wait.h>
	#include <fcntl.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <string.h>
	#include <cutils/properties.h>

	#define LOG_TAG "IdletimerController"
	#include <cutils/log.h>
	#include <logwrap/logwrap.h>

	#include "IdletimerController.h"
	#include "NetdConstants.h"

	const char* IdletimerController::LOCAL_RAW_PREROUTING = "idletimer_raw_PREROUTING";
	const char* IdletimerController::LOCAL_MANGLE_POSTROUTING = "idletimer_mangle_POSTROUTING";

	IdletimerController::IdletimerController() {
	}

	IdletimerController::~IdletimerController() {
	}
	/* return 0 or non-zero */
	int IdletimerController::runIpxtablesCmd(int argc, const char **argv) {
	int res;

	res = android_fork_execvp(argc, (char **)argv, NULL, false, false);
	ALOGV("runCmd() res=%d", res);
	return res;
	}

	bool IdletimerController::setupIptablesHooks() {
	return true;
	}

	int IdletimerController::setDefaults() {
	int res;
	const char *cmd1[] = {
	IPTABLES_PATH,
	"-t",
	"raw",
	"-F",
	LOCAL_RAW_PREROUTING
	};
	res = runIpxtablesCmd(ARRAY_SIZE(cmd1), cmd1);

	if (res)
	return res;

	const char *cmd2[] = {
	IPTABLES_PATH,
	"-t",
	"mangle",
	"-F",
	LOCAL_MANGLE_POSTROUTING
	};
	res = runIpxtablesCmd(ARRAY_SIZE(cmd2), cmd2);

	return res;
	}

	int IdletimerController::enableIdletimerControl() {
	int res = setDefaults();
	return res;
	}

	int IdletimerController::disableIdletimerControl() {
	int res = setDefaults();
	return res;
	}

	int IdletimerController::modifyInterfaceIdletimer(IptOp op, const char *iface,
	uint32_t timeout,
	const char *classLabel) {
	int res;
	char timeout_str[11]; //enough to store any 32-bit unsigned decimal

	snprintf(timeout_str, sizeof(timeout_str), "%u", timeout);

	const char *cmd1[] = {
	IPTABLES_PATH,
	"-t",
	"raw",
	(op == IptOpAdd) ? "-A" : "-D",
	LOCAL_RAW_PREROUTING,
	"-i",
	iface,
	"-j",
	"IDLETIMER",
	"--timeout",
	timeout_str,
	"--label",
	classLabel,
	"--send_nl_msg",
	"1"
	};
	res = runIpxtablesCmd(ARRAY_SIZE(cmd1), cmd1);

	if (res)
	return res;

	const char *cmd2[] = {
	IPTABLES_PATH,
	"-t",
	"mangle",
	(op == IptOpAdd) ? "-A" : "-D",
	LOCAL_MANGLE_POSTROUTING,
	"-o",
	iface,
	"-j",
	"IDLETIMER",
	"--timeout",
	timeout_str,
	"--label",
	classLabel,
	"--send_nl_msg",
	"1"
	};
	res = runIpxtablesCmd(ARRAY_SIZE(cmd2), cmd2);

	return res;
	}

	int IdletimerController::addInterfaceIdletimer(const char *iface,
	uint32_t timeout,
	const char *classLabel) {
	return modifyInterfaceIdletimer(IptOpAdd, iface, timeout, classLabel);
	}

	int IdletimerController::removeInterfaceIdletimer(const char *iface,
	uint32_t timeout,
	const char *classLabel) {
	return modifyInterfaceIdletimer(IptOpDelete, iface, timeout, classLabel);
	}