1 /**
2  * Copyright (c) 2021, 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 #include "unsolicited_event_listener.h"
18 
19 #include <thread>
20 
21 #include <android-base/chrono_utils.h>
22 #include <android-base/format.h>
23 
24 namespace android::net::resolv::aidl {
25 
26 using ::aidl::android::net::resolv::aidl::DnsHealthEventParcel;
27 using ::aidl::android::net::resolv::aidl::IDnsResolverUnsolicitedEventListener;
28 using ::aidl::android::net::resolv::aidl::Nat64PrefixEventParcel;
29 using ::aidl::android::net::resolv::aidl::PrivateDnsValidationEventParcel;
30 using android::base::Error;
31 using android::base::Result;
32 using android::base::ScopedLockAssertion;
33 using std::chrono::milliseconds;
34 
35 constexpr milliseconds kEventTimeoutMs{5000};
36 
onDnsHealthEvent(const DnsHealthEventParcel & event)37 ::ndk::ScopedAStatus UnsolicitedEventListener::onDnsHealthEvent(const DnsHealthEventParcel& event) {
38     std::lock_guard lock(mMutex);
39     if (event.netId == mNetId) mDnsHealthResultRecords.push(event.healthResult);
40     mCv.notify_all();
41     return ::ndk::ScopedAStatus::ok();
42 }
43 
onNat64PrefixEvent(const Nat64PrefixEventParcel & event)44 ::ndk::ScopedAStatus UnsolicitedEventListener::onNat64PrefixEvent(
45         const Nat64PrefixEventParcel& event) {
46     std::lock_guard lock(mMutex);
47     mUnexpectedNat64PrefixUpdates++;
48     if (event.netId == mNetId) {
49         mNat64PrefixAddress = (event.prefixOperation ==
50                                IDnsResolverUnsolicitedEventListener::PREFIX_OPERATION_ADDED)
51                                       ? event.prefixAddress
52                                       : "";
53     }
54     mCv.notify_all();
55     return ::ndk::ScopedAStatus::ok();
56 }
57 
onPrivateDnsValidationEvent(const PrivateDnsValidationEventParcel & event)58 ::ndk::ScopedAStatus UnsolicitedEventListener::onPrivateDnsValidationEvent(
59         const PrivateDnsValidationEventParcel& event) {
60     {
61         std::lock_guard lock(mMutex);
62         // keep updating the server to have latest validation status.
63         mValidationRecords.insert_or_assign({event.netId, event.ipAddress, event.protocol},
64                                             event.validation);
65     }
66     mCv.notify_all();
67     return ::ndk::ScopedAStatus::ok();
68 }
69 
waitForPrivateDnsValidation(const std::string & serverAddr,int validation,int protocol)70 bool UnsolicitedEventListener::waitForPrivateDnsValidation(const std::string& serverAddr,
71                                                            int validation, int protocol) {
72     std::unique_lock lock(mMutex);
73     return mCv.wait_for(lock, kEventTimeoutMs, [&]() REQUIRES(mMutex) {
74         return findAndRemoveValidationRecord({mNetId, serverAddr, protocol}, validation);
75     });
76 }
77 
findAndRemoveValidationRecord(const ServerKey & key,int value)78 bool UnsolicitedEventListener::findAndRemoveValidationRecord(const ServerKey& key, int value) {
79     auto it = mValidationRecords.find(key);
80     if (it != mValidationRecords.end() && it->second == value) {
81         mValidationRecords.erase(it);
82         return true;
83     }
84     return false;
85 }
86 
waitForNat64Prefix(int operation,const milliseconds & timeout)87 bool UnsolicitedEventListener::waitForNat64Prefix(int operation, const milliseconds& timeout) {
88     const auto now = std::chrono::steady_clock::now();
89 
90     std::unique_lock lock(mMutex);
91     ScopedLockAssertion assume_lock(mMutex);
92 
93     if (mCv.wait_for(lock, timeout, [&]() REQUIRES(mMutex) {
94             return (operation == IDnsResolverUnsolicitedEventListener::PREFIX_OPERATION_ADDED &&
95                     !mNat64PrefixAddress.empty()) ||
96                    (operation == IDnsResolverUnsolicitedEventListener::PREFIX_OPERATION_REMOVED &&
97                     mNat64PrefixAddress.empty());
98         })) {
99         mUnexpectedNat64PrefixUpdates--;
100         return true;
101     }
102 
103     // Timeout.
104     return false;
105 }
106 
popDnsHealthResult()107 Result<int> UnsolicitedEventListener::popDnsHealthResult() {
108     std::unique_lock lock(mMutex);
109     ScopedLockAssertion assume_lock(mMutex);
110 
111     if (!mCv.wait_for(lock, kEventTimeoutMs,
112                       [&]() REQUIRES(mMutex) { return !mDnsHealthResultRecords.empty(); })) {
113         return Error() << "Dns health result record is empty";
114     }
115 
116     auto ret = mDnsHealthResultRecords.front();
117     mDnsHealthResultRecords.pop();
118     return ret;
119 }
120 
121 }  // namespace android::net::resolv::aidl
122