1 /*
2  * Copyright (C) 2019 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 
18 #include "DnsQueryLog.h"
19 
20 #include "util.h"
21 
22 namespace android::net {
23 
24 namespace {
25 
26 std::string maskHostname(const std::string& hostname) {
27     // Boundary issue is handled in substr().
28     return hostname.substr(0, 1) + "***";
29 }
30 
31 // Return the string of masked addresses of the first v4 address and the first v6 address.
32 std::string maskIps(const std::vector<std::string>& ips) {
33     std::string ret;
34     bool v4Found = false, v6Found = false;
35     for (const auto& ip : ips) {
36         if (auto pos = ip.find_first_of(':'); pos != ip.npos && !v6Found) {
37             ret += ip.substr(0, pos + 1) + "***, ";
38             v6Found = true;
39         } else if (auto pos = ip.find_first_of('.'); pos != ip.npos && !v4Found) {
40             ret += ip.substr(0, pos + 1) + "***, ";
41             v4Found = true;
42         }
43         if (v6Found && v4Found) break;
44     }
45     return ret.empty() ? "" : ret.substr(0, ret.length() - 2);
46 }
47 
48 }  // namespace
49 
50 void DnsQueryLog::push(Record&& record) {
51     mQueue.push(std::move(record));
52 }
53 
54 void DnsQueryLog::dump(netdutils::DumpWriter& dw) const {
55     dw.println("DNS query log (last %lld minutes):", (mValidityTimeMs / 60000).count());
56     netdutils::ScopedIndent indentStats(dw);
57     const auto now = std::chrono::system_clock::now();
58 
59     for (const auto& record : mQueue.copy()) {
60         if (now - record.timestamp > mValidityTimeMs) continue;
61 
62         const std::string maskedHostname = maskHostname(record.hostname);
63         const std::string maskedIpsStr = maskIps(record.addrs);
64         const std::string time = timestampToString(record.timestamp);
65         dw.println("time=%s netId=%u uid=%u pid=%d hostname=%s answer=[%s] (%dms)", time.c_str(),
66                    record.netId, record.uid, record.pid, maskedHostname.c_str(),
67                    maskedIpsStr.c_str(), record.timeTaken);
68     }
69 }
70 
71 }  // namespace android::net
72