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/*
* Copyright (C) 2020 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 TRACE_TAG TRANSPORT
#include "adb_mdns.h"
#include <set>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include "adb_trace.h"
#define ADB_SECURE_SERVICE_VERSION_TXT_RECORD(ver) ("v=" #ver)
const char* kADBSecurePairingServiceTxtRecord =
ADB_SECURE_SERVICE_VERSION_TXT_RECORD(ADB_SECURE_SERVICE_VERSION);
const char* kADBSecureConnectServiceTxtRecord =
ADB_SECURE_SERVICE_VERSION_TXT_RECORD(ADB_SECURE_SERVICE_VERSION);
#define ADB_FULL_MDNS_SERVICE_TYPE(atype) ("_" atype "._tcp")
const char* kADBDNSServices[] = {ADB_FULL_MDNS_SERVICE_TYPE(ADB_MDNS_SERVICE_TYPE),
ADB_FULL_MDNS_SERVICE_TYPE(ADB_MDNS_TLS_PAIRING_TYPE),
ADB_FULL_MDNS_SERVICE_TYPE(ADB_MDNS_TLS_CONNECT_TYPE)};
const char* kADBDNSServiceTxtRecords[] = {
nullptr,
kADBSecurePairingServiceTxtRecord,
kADBSecureConnectServiceTxtRecord,
};
#if ADB_HOST
namespace {
std::atomic<bool> g_allowedlist_configured{false};
[[clang::no_destroy]] std::set<int> g_autoconn_allowedlist;
void config_auto_connect_services() {
bool expected = false;
if (!g_allowedlist_configured.compare_exchange_strong(expected, true)) {
return;
}
// ADB_MDNS_AUTO_CONNECT is a comma-delimited list of mdns services
// that are allowed to auto-connect. By default, only allow "adb-tls-connect"
// to auto-connect, since this is filtered down to auto-connect only to paired
// devices.
g_autoconn_allowedlist.insert(kADBSecureConnectServiceRefIndex);
const char* srvs = getenv("ADB_MDNS_AUTO_CONNECT");
if (!srvs) {
return;
}
if (strcmp(srvs, "0") == 0) {
D("Disabling all auto-connecting");
g_autoconn_allowedlist.clear();
return;
}
if (strcmp(srvs, "all") == 0) {
D("Allow all auto-connecting");
g_autoconn_allowedlist.insert(kADBTransportServiceRefIndex);
return;
}
// Selectively choose which services to allow auto-connect.
// E.g. ADB_MDNS_AUTO_CONNECT=adb,adb-tls-connect would allow
// _adb._tcp and _adb-tls-connnect._tcp services to auto-connect.
auto srvs_list = android::base::Split(srvs, ",");
std::set<int> new_allowedlist;
for (const auto& item : srvs_list) {
auto full_srv = android::base::StringPrintf("_%s._tcp", item.data());
std::optional<int> idx = adb_DNSServiceIndexByName(full_srv);
if (idx.has_value()) {
new_allowedlist.insert(*idx);
}
}
if (!new_allowedlist.empty()) {
g_autoconn_allowedlist = std::move(new_allowedlist);
}
std::string res;
std::for_each(g_autoconn_allowedlist.begin(), g_autoconn_allowedlist.end(), [&](const int& i) {
res += kADBDNSServices[i];
res += ",";
});
D("mdns auto-connect allowedlist: [%s]", res.data());
}
} // namespace
std::optional<int> adb_DNSServiceIndexByName(std::string_view reg_type) {
for (int i = 0; i < kNumADBDNSServices; ++i) {
if (!strncmp(reg_type.data(), kADBDNSServices[i], strlen(kADBDNSServices[i]))) {
return i;
}
}
return std::nullopt;
}
bool adb_DNSServiceShouldAutoConnect(std::string_view reg_type, std::string_view service_name) {
config_auto_connect_services();
// Try to auto-connect to any "_adb" or "_adb-tls-connect" services excluding emulator services.
std::optional<int> index = adb_DNSServiceIndexByName(reg_type);
if (!index ||
(index != kADBTransportServiceRefIndex && index != kADBSecureConnectServiceRefIndex)) {
return false;
}
if (g_autoconn_allowedlist.find(*index) == g_autoconn_allowedlist.end()) {
D("Auto-connect for reg_type '%s' disabled", reg_type.data());
return false;
}
// Ignore adb-EMULATOR* service names, as it interferes with the
// emulator ports that are already connected.
if (android::base::StartsWith(service_name, "adb-EMULATOR")) {
LOG(INFO) << "Ignoring emulator transport service [" << service_name << "]";
return false;
}
return true;
}
#endif // ADB_HOST