server/TrafficController.cpp - platform/system/netd - Git at Google

 /*
  * Copyright (C) 2017 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_TAG "TrafficController"

 #include <inttypes.h>
 #include <linux/bpf.h>
 #include <linux/if_ether.h>
 #include <linux/in.h>
 #include <linux/inet_diag.h>
 #include <linux/netlink.h>
 #include <linux/sock_diag.h>
 #include <linux/unistd.h>
 #include <net/if.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
 #include <sys/wait.h>
 #include <unordered_set>
 #include <vector>

 #include <android-base/stringprintf.h>
 #include <android-base/unique_fd.h>
 #include <logwrap/logwrap.h>
 #include <netdutils/StatusOr.h>

 #include <netdutils/Misc.h>
 #include <netdutils/Syscalls.h>
 #include "TrafficController.h"
 #include "bpf/BpfUtils.h"

 #include "NetlinkListener.h"
 #include "qtaguid/qtaguid.h"

 using namespace android::bpf;

 namespace android {
 namespace net {

 using base::StringPrintf;
 using base::unique_fd;
 using netdutils::extract;
 using netdutils::Slice;
 using netdutils::sSyscalls;
 using netdutils::Status;
 using netdutils::statusFromErrno;
 using netdutils::StatusOr;
 using netdutils::status::ok;

 constexpr int kSockDiagMsgType = SOCK_DIAG_BY_FAMILY;
 constexpr int kSockDiagDoneMsgType = NLMSG_DONE;

 StatusOr<std::unique_ptr<NetlinkListenerInterface>> makeSkDestroyListener() {
     const auto& sys = sSyscalls.get();
     ASSIGN_OR_RETURN(auto event, sys.eventfd(0, EFD_CLOEXEC));
     const int domain = AF_NETLINK;
     const int type = SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK;
     const int protocol = NETLINK_INET_DIAG;
     ASSIGN_OR_RETURN(auto sock, sys.socket(domain, type, protocol));

     sockaddr_nl addr = {
         .nl_family = AF_NETLINK,
         .nl_groups = 1 << (SKNLGRP_INET_TCP_DESTROY - 1) | 1 << (SKNLGRP_INET_UDP_DESTROY - 1) |
                      1 << (SKNLGRP_INET6_TCP_DESTROY - 1) | 1 << (SKNLGRP_INET6_UDP_DESTROY - 1)};
     RETURN_IF_NOT_OK(sys.bind(sock, addr));

     const sockaddr_nl kernel = {.nl_family = AF_NETLINK};
     RETURN_IF_NOT_OK(sys.connect(sock, kernel));

     std::unique_ptr<NetlinkListenerInterface> listener =
         std::make_unique<NetlinkListener>(std::move(event), std::move(sock));

     return listener;
 }

 Status TrafficController::start() {
     ebpfSupported = hasBpfSupport();
     if (!ebpfSupported) {
         return netdutils::status::ok;
     }

     /* When netd restart from a crash without total system reboot, the program
      * is still attached to the cgroup, detach it so the program can be freed
      * and we can load and attach new program into the target cgroup.
      *
      * TODO: Scrape existing socket when run-time restart and clean up the map
      * if the socket no longer exist
      */

     ALOGI("START to load TrafficController");

     ASSIGN_OR_RETURN(mCookieTagMap,
                      setUpBPFMap(sizeof(uint64_t), sizeof(struct UidTag), COOKIE_UID_MAP_SIZE,
                                  COOKIE_UID_MAP_PATH, BPF_MAP_TYPE_HASH));

     // Allow both netd and system server to obtain map fd from the path. Chown the group to
     // net_bw_acct does not grant all process in that group the permission to access bpf maps. They
     // still need correct sepolicy to read/write the map. And only system_server and netd have that
     // permission for now.
     int ret = chown(COOKIE_UID_MAP_PATH, AID_ROOT, AID_NET_BW_ACCT);
     if (ret) {
         return statusFromErrno(errno, "change cookieTagMap group failed.");
     }
     ret = chmod(COOKIE_UID_MAP_PATH, S_IRWXU | S_IRGRP | S_IWGRP);
     if (ret) {
         return statusFromErrno(errno, "change cookieTagMap mode failed.");
     }

     ASSIGN_OR_RETURN(mUidCounterSetMap,
                      setUpBPFMap(sizeof(uint32_t), sizeof(uint32_t), UID_COUNTERSET_MAP_SIZE,
                                  UID_COUNTERSET_MAP_PATH, BPF_MAP_TYPE_HASH));
     // Only netd can access the file.
     ret = chmod(UID_COUNTERSET_MAP_PATH, S_IRWXU);
     if (ret) {
         return statusFromErrno(errno, "change uidCounterSetMap mode failed.");
     }

     ASSIGN_OR_RETURN(mUidStatsMap,
                      setUpBPFMap(sizeof(struct StatsKey), sizeof(struct StatsValue),
                                  UID_STATS_MAP_SIZE, UID_STATS_MAP_PATH, BPF_MAP_TYPE_HASH));
     // Change the file mode of pinned map so both netd and system server can get the map fd
     // from it.
     ret = chown(UID_STATS_MAP_PATH, AID_ROOT, AID_NET_BW_ACCT);
     if (ret) {
         return statusFromErrno(errno, "change uidStatsMap group failed.");
     }
     ret = chmod(UID_STATS_MAP_PATH, S_IRWXU | S_IRGRP | S_IWGRP);
     if (ret) {
         return statusFromErrno(errno, "change uidStatsMap mode failed.");
     }

     ASSIGN_OR_RETURN(mTagStatsMap,
                      setUpBPFMap(sizeof(struct StatsKey), sizeof(struct StatsValue),
                                  TAG_STATS_MAP_SIZE, TAG_STATS_MAP_PATH, BPF_MAP_TYPE_HASH));
     // Change the file mode of pinned map so both netd and system server can get the map fd
     // from the path.
     ret = chown(TAG_STATS_MAP_PATH, AID_ROOT, AID_NET_BW_STATS);
     if (ret) {
         return statusFromErrno(errno, "change tagStatsMap group failed.");
     }
     ret = chmod(TAG_STATS_MAP_PATH, S_IRWXU | S_IRGRP | S_IWGRP);
     if (ret) {
         return statusFromErrno(errno, "change tagStatsMap mode failed.");
     }

     auto result = makeSkDestroyListener();
     if (!isOk(result)) {
         ALOGE("Unable to create SkDestroyListener: %s", toString(result).c_str());
     } else {
         mSkDestroyListener = std::move(result.value());
     }
     // Rx handler extracts nfgenmsg looks up and invokes registered dispatch function.
     const auto rxHandler = [this](const nlmsghdr&, const Slice msg) {
         inet_diag_msg diagmsg = {};
         if (extract(msg, diagmsg) < sizeof(inet_diag_msg)) {
             ALOGE("unrecognized netlink message: %s", toString(msg).c_str());
             return;
         }
         uint64_t sock_cookie = static_cast<uint64_t>(diagmsg.id.idiag_cookie[0]) |
                                (static_cast<uint64_t>(diagmsg.id.idiag_cookie[1]) << 32);

         deleteMapEntry(mCookieTagMap, &sock_cookie);
     };
     expectOk(mSkDestroyListener->subscribe(kSockDiagMsgType, rxHandler));

     // In case multiple netlink message comes in as a stream, we need to handle the rxDone message
     // properly.
     const auto rxDoneHandler = [](const nlmsghdr&, const Slice msg) {
         // Ignore NLMSG_DONE  messages
         inet_diag_msg diagmsg = {};
         extract(msg, diagmsg);
     };
     expectOk(mSkDestroyListener->subscribe(kSockDiagDoneMsgType, rxDoneHandler));

     int* status = nullptr;

     std::vector<const char*> prog_args{
         "/system/bin/bpfloader",
     };
     ret = access(BPF_INGRESS_PROG_PATH, R_OK);
     if (ret != 0 && errno == ENOENT) {
         prog_args.push_back((char*)"-i");
     }
     ret = access(BPF_EGRESS_PROG_PATH, R_OK);
     if (ret != 0 && errno == ENOENT) {
         prog_args.push_back((char*)"-e");
     }

     if (prog_args.size() == 1) {
         // both program are loaded already.
         return netdutils::status::ok;
     }

     prog_args.push_back(nullptr);
     ret = android_fork_execvp(prog_args.size(), (char**)prog_args.data(), status, false, true);
     if (ret) {
         ret = errno;
         ALOGE("failed to execute %s: %s", prog_args[0], strerror(errno));
         return statusFromErrno(ret, "run bpf loader failed");
     }
     return netdutils::status::ok;
 }

 int TrafficController::tagSocket(int sockFd, uint32_t tag, uid_t uid) {
     if (legacy_tagSocket(sockFd, tag, uid)) return -errno;
     if (!ebpfSupported) return 0;

     uint64_t sock_cookie = getSocketCookie(sockFd);
     if (sock_cookie == INET_DIAG_NOCOOKIE) return -errno;
     UidTag newKey = {.uid = (uint32_t)uid, .tag = tag};

     // Update the tag information of a socket to the cookieUidMap. Use BPF_ANY
     // flag so it will insert a new entry to the map if that value doesn't exist
     // yet. And update the tag if there is already a tag stored. Since the eBPF
     // program in kernel only read this map, and is protected by rcu read lock. It
     // should be fine to cocurrently update the map while eBPF program is running.
     int res = writeToMapEntry(mCookieTagMap, &sock_cookie, &newKey, BPF_ANY);
     if (res < 0) {
         res = -errno;
         ALOGE("Failed to tag the socket: %s, fd: %d", strerror(errno), mCookieTagMap.get());
     }

     return res;
 }

 int TrafficController::untagSocket(int sockFd) {
     if (legacy_untagSocket(sockFd)) return -errno;
     if (!ebpfSupported) return 0;
     uint64_t sock_cookie = getSocketCookie(sockFd);

     if (sock_cookie == INET_DIAG_NOCOOKIE) return -errno;
     int res = deleteMapEntry(mCookieTagMap, &sock_cookie);
     if (res) {
         res = -errno;
         ALOGE("Failed to untag socket: %s\n", strerror(errno));
     }
     return res;
 }

 int TrafficController::setCounterSet(int counterSetNum, uid_t uid) {
     if (counterSetNum < 0 || counterSetNum >= COUNTERSETS_LIMIT) return -EINVAL;
     int res;
     if (legacy_setCounterSet(counterSetNum, uid)) return -errno;
     if (!ebpfSupported) return 0;

     // The default counter set for all uid is 0, so deleting the current counterset for that uid
     // will automatically set it to 0.
     if (counterSetNum == 0) {
         res = deleteMapEntry(mUidCounterSetMap, &uid);
         if (res == 0 || (res == -1 && errno == ENOENT)) {
             return 0;
         } else {
             ALOGE("Failed to delete the counterSet: %s\n", strerror(errno));
             return -errno;
         }
     }

     res = writeToMapEntry(mUidCounterSetMap, &uid, &counterSetNum, BPF_ANY);
     if (res < 0) {
         res = -errno;
         ALOGE("Failed to set the counterSet: %s, fd: %d", strerror(errno), mUidCounterSetMap.get());
     }
     return res;
 }

 // TODO: Add a lock for delete tag Data so when several request for different uid comes in, they do
 // not race with each other.
 int TrafficController::deleteTagData(uint32_t tag, uid_t uid) {
     int res = 0;

     if (legacy_deleteTagData(tag, uid)) return -errno;
     if (!ebpfSupported) return 0;

     uint64_t curCookie = NONEXIST_COOKIE;
     uint64_t nextCookie = 0;
     UidTag tmp_uidtag;
     std::vector<uint64_t> cookieList;
     // First we go through the cookieTagMap to delete the target uid tag combination. Or delete all
     // the tags related to the uid if the tag is 0, we start the map iteration with a cookie of
     // INET_DIAG_NOCOOKIE because it's guaranteed that that will not be in the map.
     while (getNextMapKey(mCookieTagMap, &curCookie, &nextCookie) != -1) {
         res = findMapEntry(mCookieTagMap, &nextCookie, &tmp_uidtag);
         if (res < 0) {
             res = -errno;
             ALOGE("Failed to get tag info(cookie = %" PRIu64 ": %s\n", nextCookie, strerror(errno));
             // Continue to look for next entry.
             curCookie = nextCookie;
             continue;
         }

         if (tmp_uidtag.uid == uid && (tmp_uidtag.tag == tag || tag == 0)) {
             res = deleteMapEntry(mCookieTagMap, &nextCookie);
             if (res < 0 && errno != ENOENT) {
                 res = -errno;
                 ALOGE("Failed to delete data(cookie = %" PRIu64 "): %s\n", nextCookie,
                       strerror(errno));
             }
         } else {
             // Move forward to next cookie in the map.
             curCookie = nextCookie;
         }
     }

     // Now we go through the Tag stats map and delete the data entry with correct uid and tag
     // combination. Or all tag stats under that uid if the target tag is 0. The initial key is
     // set to the nonexist_statskey because it will never be in the map, and thus getNextMapKey will
     // return 0 and set nextKey to the first key in the map.
     struct StatsKey curKey, nextKey;
     curKey = android::bpf::NONEXISTENT_STATSKEY;
     while (getNextMapKey(mTagStatsMap, &curKey, &nextKey) != -1) {
         if (nextKey.uid == uid && (nextKey.tag == tag || tag == 0)) {
             res = deleteMapEntry(mTagStatsMap, &nextKey);
             if (res < 0 && errno != ENOENT) {
                 // Skip the current entry if unexpected error happened.
                 ALOGE("Failed to delete data(uid=%u, tag=%u): %s\n", nextKey.uid, nextKey.tag,
                       strerror(errno));
                 curKey = nextKey;
             }
         } else {
             curKey = nextKey;
         }
     }

     // If the tag is not zero, we already deleted all the data entry required. If tag is 0, we also
     // need to delete the stats stored in uidStatsMap and counterSet map.
     if (tag != 0) return 0;

     res = deleteMapEntry(mUidCounterSetMap, &uid);
     if (res < 0 && errno != ENOENT) {
         ALOGE("Failed to delete counterSet data(uid=%u, tag=%u): %s\n", uid, tag, strerror(errno));
     }

     // For the uid stats deleted from the map, move them into a special
     // removed uid entry. The removed uid is stored in uid 0, tag 0 and
     // counterSet as COUNTERSETS_LIMIT.
     StatsKey removedStatsKey = {0, 0, COUNTERSETS_LIMIT, 0};
     StatsValue removedStatsTotal = {};
     res = findMapEntry(mUidStatsMap, &removedStatsKey, &removedStatsTotal);
     if (res < 0 && errno != ENOENT) {
         ALOGE("Failed to get stats of removed uid: %s", strerror(errno));
     }

     curKey = android::bpf::NONEXISTENT_STATSKEY;
     while (getNextMapKey(mUidStatsMap, &curKey, &nextKey) != -1) {
         if (nextKey.uid == uid) {
             StatsValue old_stats = {};
             res = findMapEntry(mUidStatsMap, &nextKey, &old_stats);
             if (res < 0) {
                 if (errno != ENOENT) {
                     // if errno is ENOENT Somebody else deleted nextKey. Lookup the next key from
                     // curKey. If we have other error. Skip this key to avoid an infinite loop.
                     curKey = nextKey;
                 }
                 continue;
             }
             res = deleteMapEntry(mUidStatsMap, &nextKey);
             if (res < 0 && errno != ENOENT) {
                 ALOGE("Failed to delete data(uid=%u, tag=%u): %s\n", nextKey.uid, nextKey.tag,
                       strerror(errno));
                 curKey = nextKey;
                 continue;
             }
             removedStatsTotal.rxTcpPackets += old_stats.rxTcpPackets;
             removedStatsTotal.rxTcpBytes += old_stats.rxTcpBytes;
             removedStatsTotal.txTcpPackets += old_stats.txTcpPackets;
             removedStatsTotal.txTcpBytes += old_stats.txTcpBytes;
             removedStatsTotal.rxUdpPackets += old_stats.rxUdpPackets;
             removedStatsTotal.rxUdpBytes += old_stats.rxUdpBytes;
             removedStatsTotal.txUdpPackets += old_stats.txUdpPackets;
             removedStatsTotal.txUdpBytes += old_stats.txUdpBytes;
             removedStatsTotal.rxOtherPackets += old_stats.rxOtherPackets;
             removedStatsTotal.rxOtherBytes += old_stats.rxOtherBytes;
             removedStatsTotal.txOtherPackets += old_stats.txOtherPackets;
             removedStatsTotal.txOtherBytes += old_stats.txOtherBytes;
         } else {
             curKey = nextKey;
         }
     }

     res = writeToMapEntry(mUidStatsMap, &removedStatsKey, &removedStatsTotal, BPF_ANY);
     if (res) {
         res = -errno;
         ALOGE("Failed to add deleting stats to removed uid: %s", strerror(errno));
     }
     return res;
 }

 bool TrafficController::checkBpfStatsEnable() {
     return ebpfSupported;
 }

 }  // namespace net
 }  // namespace android
	/*
	* Copyright (C) 2017 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_TAG "TrafficController"

	#include <inttypes.h>
	#include <linux/bpf.h>
	#include <linux/if_ether.h>
	#include <linux/in.h>
	#include <linux/inet_diag.h>
	#include <linux/netlink.h>
	#include <linux/sock_diag.h>
	#include <linux/unistd.h>
	#include <net/if.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/utsname.h>
	#include <sys/wait.h>
	#include <unordered_set>
	#include <vector>

	#include <android-base/stringprintf.h>
	#include <android-base/unique_fd.h>
	#include <logwrap/logwrap.h>
	#include <netdutils/StatusOr.h>

	#include <netdutils/Misc.h>
	#include <netdutils/Syscalls.h>
	#include "TrafficController.h"
	#include "bpf/BpfUtils.h"

	#include "NetlinkListener.h"
	#include "qtaguid/qtaguid.h"

	using namespace android::bpf;

	namespace android {
	namespace net {

	using base::StringPrintf;
	using base::unique_fd;
	using netdutils::extract;
	using netdutils::Slice;
	using netdutils::sSyscalls;
	using netdutils::Status;
	using netdutils::statusFromErrno;
	using netdutils::StatusOr;
	using netdutils::status::ok;

	constexpr int kSockDiagMsgType = SOCK_DIAG_BY_FAMILY;
	constexpr int kSockDiagDoneMsgType = NLMSG_DONE;

	StatusOr<std::unique_ptr<NetlinkListenerInterface>> makeSkDestroyListener() {
	const auto& sys = sSyscalls.get();
	ASSIGN_OR_RETURN(auto event, sys.eventfd(0, EFD_CLOEXEC));
	const int domain = AF_NETLINK;
	const int type = SOCK_DGRAM \| SOCK_CLOEXEC \| SOCK_NONBLOCK;
	const int protocol = NETLINK_INET_DIAG;
	ASSIGN_OR_RETURN(auto sock, sys.socket(domain, type, protocol));

	sockaddr_nl addr = {
	.nl_family = AF_NETLINK,
	.nl_groups = 1 << (SKNLGRP_INET_TCP_DESTROY - 1) \| 1 << (SKNLGRP_INET_UDP_DESTROY - 1) \|
	1 << (SKNLGRP_INET6_TCP_DESTROY - 1) \| 1 << (SKNLGRP_INET6_UDP_DESTROY - 1)};
	RETURN_IF_NOT_OK(sys.bind(sock, addr));

	const sockaddr_nl kernel = {.nl_family = AF_NETLINK};
	RETURN_IF_NOT_OK(sys.connect(sock, kernel));

	std::unique_ptr<NetlinkListenerInterface> listener =
	std::make_unique<NetlinkListener>(std::move(event), std::move(sock));

	return listener;
	}

	Status TrafficController::start() {
	ebpfSupported = hasBpfSupport();
	if (!ebpfSupported) {
	return netdutils::status::ok;
	}

	/* When netd restart from a crash without total system reboot, the program
	* is still attached to the cgroup, detach it so the program can be freed
	* and we can load and attach new program into the target cgroup.
	*
	* TODO: Scrape existing socket when run-time restart and clean up the map
	* if the socket no longer exist
	*/

	ALOGI("START to load TrafficController");

	ASSIGN_OR_RETURN(mCookieTagMap,
	setUpBPFMap(sizeof(uint64_t), sizeof(struct UidTag), COOKIE_UID_MAP_SIZE,
	COOKIE_UID_MAP_PATH, BPF_MAP_TYPE_HASH));

	// Allow both netd and system server to obtain map fd from the path. Chown the group to
	// net_bw_acct does not grant all process in that group the permission to access bpf maps. They
	// still need correct sepolicy to read/write the map. And only system_server and netd have that
	// permission for now.
	int ret = chown(COOKIE_UID_MAP_PATH, AID_ROOT, AID_NET_BW_ACCT);
	if (ret) {
	return statusFromErrno(errno, "change cookieTagMap group failed.");
	}
	ret = chmod(COOKIE_UID_MAP_PATH, S_IRWXU \| S_IRGRP \| S_IWGRP);
	if (ret) {
	return statusFromErrno(errno, "change cookieTagMap mode failed.");
	}

	ASSIGN_OR_RETURN(mUidCounterSetMap,
	setUpBPFMap(sizeof(uint32_t), sizeof(uint32_t), UID_COUNTERSET_MAP_SIZE,
	UID_COUNTERSET_MAP_PATH, BPF_MAP_TYPE_HASH));
	// Only netd can access the file.
	ret = chmod(UID_COUNTERSET_MAP_PATH, S_IRWXU);
	if (ret) {
	return statusFromErrno(errno, "change uidCounterSetMap mode failed.");
	}

	ASSIGN_OR_RETURN(mUidStatsMap,
	setUpBPFMap(sizeof(struct StatsKey), sizeof(struct StatsValue),
	UID_STATS_MAP_SIZE, UID_STATS_MAP_PATH, BPF_MAP_TYPE_HASH));
	// Change the file mode of pinned map so both netd and system server can get the map fd
	// from it.
	ret = chown(UID_STATS_MAP_PATH, AID_ROOT, AID_NET_BW_ACCT);
	if (ret) {
	return statusFromErrno(errno, "change uidStatsMap group failed.");
	}
	ret = chmod(UID_STATS_MAP_PATH, S_IRWXU \| S_IRGRP \| S_IWGRP);
	if (ret) {
	return statusFromErrno(errno, "change uidStatsMap mode failed.");
	}

	ASSIGN_OR_RETURN(mTagStatsMap,
	setUpBPFMap(sizeof(struct StatsKey), sizeof(struct StatsValue),
	TAG_STATS_MAP_SIZE, TAG_STATS_MAP_PATH, BPF_MAP_TYPE_HASH));
	// Change the file mode of pinned map so both netd and system server can get the map fd
	// from the path.
	ret = chown(TAG_STATS_MAP_PATH, AID_ROOT, AID_NET_BW_STATS);
	if (ret) {
	return statusFromErrno(errno, "change tagStatsMap group failed.");
	}
	ret = chmod(TAG_STATS_MAP_PATH, S_IRWXU \| S_IRGRP \| S_IWGRP);
	if (ret) {
	return statusFromErrno(errno, "change tagStatsMap mode failed.");
	}

	auto result = makeSkDestroyListener();
	if (!isOk(result)) {
	ALOGE("Unable to create SkDestroyListener: %s", toString(result).c_str());
	} else {
	mSkDestroyListener = std::move(result.value());
	}
	// Rx handler extracts nfgenmsg looks up and invokes registered dispatch function.
	const auto rxHandler = [this](const nlmsghdr&, const Slice msg) {
	inet_diag_msg diagmsg = {};
	if (extract(msg, diagmsg) < sizeof(inet_diag_msg)) {
	ALOGE("unrecognized netlink message: %s", toString(msg).c_str());
	return;
	}
	uint64_t sock_cookie = static_cast<uint64_t>(diagmsg.id.idiag_cookie[0]) \|
	(static_cast<uint64_t>(diagmsg.id.idiag_cookie[1]) << 32);

	deleteMapEntry(mCookieTagMap, &sock_cookie);
	};
	expectOk(mSkDestroyListener->subscribe(kSockDiagMsgType, rxHandler));

	// In case multiple netlink message comes in as a stream, we need to handle the rxDone message
	// properly.
	const auto rxDoneHandler = [](const nlmsghdr&, const Slice msg) {
	// Ignore NLMSG_DONE messages
	inet_diag_msg diagmsg = {};
	extract(msg, diagmsg);
	};
	expectOk(mSkDestroyListener->subscribe(kSockDiagDoneMsgType, rxDoneHandler));

	int* status = nullptr;

	std::vector<const char*> prog_args{
	"/system/bin/bpfloader",
	};
	ret = access(BPF_INGRESS_PROG_PATH, R_OK);
	if (ret != 0 && errno == ENOENT) {
	prog_args.push_back((char*)"-i");
	}
	ret = access(BPF_EGRESS_PROG_PATH, R_OK);
	if (ret != 0 && errno == ENOENT) {
	prog_args.push_back((char*)"-e");
	}

	if (prog_args.size() == 1) {
	// both program are loaded already.
	return netdutils::status::ok;
	}

	prog_args.push_back(nullptr);
	ret = android_fork_execvp(prog_args.size(), (char**)prog_args.data(), status, false, true);
	if (ret) {
	ret = errno;
	ALOGE("failed to execute %s: %s", prog_args[0], strerror(errno));
	return statusFromErrno(ret, "run bpf loader failed");
	}
	return netdutils::status::ok;
	}

	int TrafficController::tagSocket(int sockFd, uint32_t tag, uid_t uid) {
	if (legacy_tagSocket(sockFd, tag, uid)) return -errno;
	if (!ebpfSupported) return 0;

	uint64_t sock_cookie = getSocketCookie(sockFd);
	if (sock_cookie == INET_DIAG_NOCOOKIE) return -errno;
	UidTag newKey = {.uid = (uint32_t)uid, .tag = tag};

	// Update the tag information of a socket to the cookieUidMap. Use BPF_ANY
	// flag so it will insert a new entry to the map if that value doesn't exist
	// yet. And update the tag if there is already a tag stored. Since the eBPF
	// program in kernel only read this map, and is protected by rcu read lock. It
	// should be fine to cocurrently update the map while eBPF program is running.
	int res = writeToMapEntry(mCookieTagMap, &sock_cookie, &newKey, BPF_ANY);
	if (res < 0) {
	res = -errno;
	ALOGE("Failed to tag the socket: %s, fd: %d", strerror(errno), mCookieTagMap.get());
	}

	return res;
	}

	int TrafficController::untagSocket(int sockFd) {
	if (legacy_untagSocket(sockFd)) return -errno;
	if (!ebpfSupported) return 0;
	uint64_t sock_cookie = getSocketCookie(sockFd);

	if (sock_cookie == INET_DIAG_NOCOOKIE) return -errno;
	int res = deleteMapEntry(mCookieTagMap, &sock_cookie);
	if (res) {
	res = -errno;
	ALOGE("Failed to untag socket: %s\n", strerror(errno));
	}
	return res;
	}

	int TrafficController::setCounterSet(int counterSetNum, uid_t uid) {
	if (counterSetNum < 0 \|\| counterSetNum >= COUNTERSETS_LIMIT) return -EINVAL;
	int res;
	if (legacy_setCounterSet(counterSetNum, uid)) return -errno;
	if (!ebpfSupported) return 0;

	// The default counter set for all uid is 0, so deleting the current counterset for that uid
	// will automatically set it to 0.
	if (counterSetNum == 0) {
	res = deleteMapEntry(mUidCounterSetMap, &uid);
	if (res == 0 \|\| (res == -1 && errno == ENOENT)) {
	return 0;
	} else {
	ALOGE("Failed to delete the counterSet: %s\n", strerror(errno));
	return -errno;
	}
	}

	res = writeToMapEntry(mUidCounterSetMap, &uid, &counterSetNum, BPF_ANY);
	if (res < 0) {
	res = -errno;
	ALOGE("Failed to set the counterSet: %s, fd: %d", strerror(errno), mUidCounterSetMap.get());
	}
	return res;
	}

	// TODO: Add a lock for delete tag Data so when several request for different uid comes in, they do
	// not race with each other.
	int TrafficController::deleteTagData(uint32_t tag, uid_t uid) {
	int res = 0;

	if (legacy_deleteTagData(tag, uid)) return -errno;
	if (!ebpfSupported) return 0;

	uint64_t curCookie = NONEXIST_COOKIE;
	uint64_t nextCookie = 0;
	UidTag tmp_uidtag;
	std::vector<uint64_t> cookieList;
	// First we go through the cookieTagMap to delete the target uid tag combination. Or delete all
	// the tags related to the uid if the tag is 0, we start the map iteration with a cookie of
	// INET_DIAG_NOCOOKIE because it's guaranteed that that will not be in the map.
	while (getNextMapKey(mCookieTagMap, &curCookie, &nextCookie) != -1) {
	res = findMapEntry(mCookieTagMap, &nextCookie, &tmp_uidtag);
	if (res < 0) {
	res = -errno;
	ALOGE("Failed to get tag info(cookie = %" PRIu64 ": %s\n", nextCookie, strerror(errno));
	// Continue to look for next entry.
	curCookie = nextCookie;
	continue;
	}

	if (tmp_uidtag.uid == uid && (tmp_uidtag.tag == tag \|\| tag == 0)) {
	res = deleteMapEntry(mCookieTagMap, &nextCookie);
	if (res < 0 && errno != ENOENT) {
	res = -errno;
	ALOGE("Failed to delete data(cookie = %" PRIu64 "): %s\n", nextCookie,
	strerror(errno));
	}
	} else {
	// Move forward to next cookie in the map.
	curCookie = nextCookie;
	}
	}

	// Now we go through the Tag stats map and delete the data entry with correct uid and tag
	// combination. Or all tag stats under that uid if the target tag is 0. The initial key is
	// set to the nonexist_statskey because it will never be in the map, and thus getNextMapKey will
	// return 0 and set nextKey to the first key in the map.
	struct StatsKey curKey, nextKey;
	curKey = android::bpf::NONEXISTENT_STATSKEY;
	while (getNextMapKey(mTagStatsMap, &curKey, &nextKey) != -1) {
	if (nextKey.uid == uid && (nextKey.tag == tag \|\| tag == 0)) {
	res = deleteMapEntry(mTagStatsMap, &nextKey);
	if (res < 0 && errno != ENOENT) {
	// Skip the current entry if unexpected error happened.
	ALOGE("Failed to delete data(uid=%u, tag=%u): %s\n", nextKey.uid, nextKey.tag,
	strerror(errno));
	curKey = nextKey;
	}
	} else {
	curKey = nextKey;
	}
	}

	// If the tag is not zero, we already deleted all the data entry required. If tag is 0, we also
	// need to delete the stats stored in uidStatsMap and counterSet map.
	if (tag != 0) return 0;

	res = deleteMapEntry(mUidCounterSetMap, &uid);
	if (res < 0 && errno != ENOENT) {
	ALOGE("Failed to delete counterSet data(uid=%u, tag=%u): %s\n", uid, tag, strerror(errno));
	}

	// For the uid stats deleted from the map, move them into a special
	// removed uid entry. The removed uid is stored in uid 0, tag 0 and
	// counterSet as COUNTERSETS_LIMIT.
	StatsKey removedStatsKey = {0, 0, COUNTERSETS_LIMIT, 0};
	StatsValue removedStatsTotal = {};
	res = findMapEntry(mUidStatsMap, &removedStatsKey, &removedStatsTotal);
	if (res < 0 && errno != ENOENT) {
	ALOGE("Failed to get stats of removed uid: %s", strerror(errno));
	}

	curKey = android::bpf::NONEXISTENT_STATSKEY;
	while (getNextMapKey(mUidStatsMap, &curKey, &nextKey) != -1) {
	if (nextKey.uid == uid) {
	StatsValue old_stats = {};
	res = findMapEntry(mUidStatsMap, &nextKey, &old_stats);
	if (res < 0) {
	if (errno != ENOENT) {
	// if errno is ENOENT Somebody else deleted nextKey. Lookup the next key from
	// curKey. If we have other error. Skip this key to avoid an infinite loop.
	curKey = nextKey;
	}
	continue;
	}
	res = deleteMapEntry(mUidStatsMap, &nextKey);
	if (res < 0 && errno != ENOENT) {
	ALOGE("Failed to delete data(uid=%u, tag=%u): %s\n", nextKey.uid, nextKey.tag,
	strerror(errno));
	curKey = nextKey;
	continue;
	}
	removedStatsTotal.rxTcpPackets += old_stats.rxTcpPackets;
	removedStatsTotal.rxTcpBytes += old_stats.rxTcpBytes;
	removedStatsTotal.txTcpPackets += old_stats.txTcpPackets;
	removedStatsTotal.txTcpBytes += old_stats.txTcpBytes;
	removedStatsTotal.rxUdpPackets += old_stats.rxUdpPackets;
	removedStatsTotal.rxUdpBytes += old_stats.rxUdpBytes;
	removedStatsTotal.txUdpPackets += old_stats.txUdpPackets;
	removedStatsTotal.txUdpBytes += old_stats.txUdpBytes;
	removedStatsTotal.rxOtherPackets += old_stats.rxOtherPackets;
	removedStatsTotal.rxOtherBytes += old_stats.rxOtherBytes;
	removedStatsTotal.txOtherPackets += old_stats.txOtherPackets;
	removedStatsTotal.txOtherBytes += old_stats.txOtherBytes;
	} else {
	curKey = nextKey;
	}
	}

	res = writeToMapEntry(mUidStatsMap, &removedStatsKey, &removedStatsTotal, BPF_ANY);
	if (res) {
	res = -errno;
	ALOGE("Failed to add deleting stats to removed uid: %s", strerror(errno));
	}
	return res;
	}

	bool TrafficController::checkBpfStatsEnable() {
	return ebpfSupported;
	}

	} // namespace net
	} // namespace android