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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "WakeupController"
     18 
     19 #include <endian.h>
     20 #include <linux/netfilter/nfnetlink.h>
     21 #include <linux/netfilter/nfnetlink_log.h>
     22 #include <iostream>
     23 
     24 #include <android-base/stringprintf.h>
     25 #include <cutils/log.h>
     26 #include <netdutils/Netfilter.h>
     27 #include <netdutils/Netlink.h>
     28 
     29 #include "IptablesRestoreController.h"
     30 #include "NetlinkManager.h"
     31 #include "WakeupController.h"
     32 
     33 namespace android {
     34 namespace net {
     35 
     36 using base::StringPrintf;
     37 using netdutils::Slice;
     38 using netdutils::Status;
     39 
     40 const char WakeupController::LOCAL_MANGLE_INPUT[] = "wakeupctrl_mangle_INPUT";
     41 
     42 WakeupController::~WakeupController() {
     43     expectOk(mListener->unsubscribe(NetlinkManager::NFLOG_WAKEUP_GROUP));
     44 }
     45 
     46 netdutils::Status WakeupController::init(NFLogListenerInterface* listener) {
     47     mListener = listener;
     48     const auto msgHandler = [this](const nlmsghdr&, const nfgenmsg&, const Slice msg) {
     49         std::string prefix;
     50         uid_t uid = -1;
     51         gid_t gid = -1;
     52         uint64_t timestampNs = -1;
     53         const auto attrHandler = [&prefix, &uid, &gid, &timestampNs](const nlattr attr,
     54                                                                      const Slice payload) {
     55             switch (attr.nla_type) {
     56                 case NFULA_TIMESTAMP: {
     57                     timespec timespec = {};
     58                     extract(payload, timespec);
     59                     constexpr uint64_t kNsPerS = 1000000000ULL;
     60                     timestampNs = be32toh(timespec.tv_nsec) + (be32toh(timespec.tv_sec) * kNsPerS);
     61                     break;
     62                 }
     63                 case NFULA_PREFIX:
     64                     // Strip trailing '\0'
     65                     prefix = toString(take(payload, payload.size() - 1));
     66                     break;
     67                 case NFULA_UID:
     68                     extract(payload, uid);
     69                     uid = be32toh(uid);
     70                     break;
     71                 case NFULA_GID:
     72                     extract(payload, gid);
     73                     gid = be32toh(gid);
     74                     break;
     75                 default:
     76                     break;
     77             }
     78         };
     79         forEachNetlinkAttribute(msg, attrHandler);
     80         mReport(prefix, uid, gid, timestampNs);
     81     };
     82     return mListener->subscribe(NetlinkManager::NFLOG_WAKEUP_GROUP, msgHandler);
     83 }
     84 
     85 Status WakeupController::addInterface(const std::string& ifName, const std::string& prefix,
     86                                     uint32_t mark, uint32_t mask) {
     87     return execIptables("-A", ifName, prefix, mark, mask);
     88 }
     89 
     90 Status WakeupController::delInterface(const std::string& ifName, const std::string& prefix,
     91                                     uint32_t mark, uint32_t mask) {
     92     return execIptables("-D", ifName, prefix, mark, mask);
     93 }
     94 
     95 Status WakeupController::execIptables(const std::string& action, const std::string& ifName,
     96                                       const std::string& prefix, uint32_t mark, uint32_t mask) {
     97     // NFLOG messages to batch before releasing to userspace
     98     constexpr int kBatch = 8;
     99     // Max log message rate in packets/second
    100     constexpr int kRateLimit = 10;
    101     const char kFormat[] =
    102         "*mangle\n%s %s -i %s -j NFLOG --nflog-prefix %s --nflog-group %d --nflog-threshold %d"
    103         " -m mark --mark 0x%08x/0x%08x -m limit --limit %d/s\nCOMMIT\n";
    104     const auto cmd = StringPrintf(
    105         kFormat, action.c_str(), WakeupController::LOCAL_MANGLE_INPUT, ifName.c_str(),
    106         prefix.c_str(), NetlinkManager::NFLOG_WAKEUP_GROUP, kBatch, mark, mask, kRateLimit);
    107 
    108     std::string out;
    109     auto rv = mIptables->execute(V4V6, cmd, &out);
    110     if (rv != 0) {
    111         auto s = Status(rv, "Failed to execute iptables cmd: " + cmd + ", out: " + out);
    112         ALOGE("%s", toString(s).c_str());
    113         return s;
    114     }
    115     return netdutils::status::ok;
    116 }
    117 
    118 }  // namespace net
    119 }  // namespace android
    120