2 * Copyright (C) 2014 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 // The methods in this file are called from multiple threads (from CommandListener, FwmarkServer
20 // and DnsProxyListener). So, all accesses to shared state are guarded by a lock.
22 // In some cases, a single non-const method acquires and releases the lock several times, like so:
23 // if (isValidNetwork(...)) { // isValidNetwork() acquires and releases the lock.
24 // setDefaultNetwork(...); // setDefaultNetwork() also acquires and releases the lock.
26 // It might seem that this allows races where the state changes between the two statements, but in
27 // fact there are no races because:
28 // 1. This pattern only occurs in non-const methods (i.e., those that mutate state).
29 // 2. Only CommandListener calls these non-const methods. The others call only const methods.
30 // 3. CommandListener only processes one command at a time. I.e., it's serialized.
31 // Thus, no other mutation can occur in between the two statements above.
33 #include "NetworkController.h"
35 #define LOG_TAG "Netd"
38 #include "cutils/misc.h"
39 #include "resolv_netid.h"
41 #include "Controllers.h"
42 #include "DummyNetwork.h"
43 #include "DumpWriter.h"
45 #include "LocalNetwork.h"
46 #include "PhysicalNetwork.h"
47 #include "RouteController.h"
48 #include "VirtualNetwork.h"
52 // Keep these in sync with ConnectivityService.java.
53 const unsigned MIN_NET_ID = 100;
54 const unsigned MAX_NET_ID = 65535;
58 const unsigned NetworkController::MIN_OEM_ID = 1;
59 const unsigned NetworkController::MAX_OEM_ID = 50;
60 const unsigned NetworkController::DUMMY_NET_ID = 51;
61 // NetIds 52..98 are reserved for future use.
62 const unsigned NetworkController::LOCAL_NET_ID = 99;
64 // All calls to methods here are made while holding a write lock on mRWLock.
65 class NetworkController::DelegateImpl : public PhysicalNetwork::Delegate {
67 explicit DelegateImpl(NetworkController* networkController);
68 virtual ~DelegateImpl();
70 int modifyFallthrough(unsigned vpnNetId, const std::string& physicalInterface,
71 Permission permission, bool add) WARN_UNUSED_RESULT;
74 int addFallthrough(const std::string& physicalInterface,
75 Permission permission) override WARN_UNUSED_RESULT;
76 int removeFallthrough(const std::string& physicalInterface,
77 Permission permission) override WARN_UNUSED_RESULT;
79 int modifyFallthrough(const std::string& physicalInterface, Permission permission,
80 bool add) WARN_UNUSED_RESULT;
82 NetworkController* const mNetworkController;
85 NetworkController::DelegateImpl::DelegateImpl(NetworkController* networkController) :
86 mNetworkController(networkController) {
89 NetworkController::DelegateImpl::~DelegateImpl() {
92 int NetworkController::DelegateImpl::modifyFallthrough(unsigned vpnNetId,
93 const std::string& physicalInterface,
94 Permission permission, bool add) {
96 if (int ret = RouteController::addVirtualNetworkFallthrough(vpnNetId,
97 physicalInterface.c_str(),
99 ALOGE("failed to add fallthrough to %s for VPN netId %u", physicalInterface.c_str(),
104 if (int ret = RouteController::removeVirtualNetworkFallthrough(vpnNetId,
105 physicalInterface.c_str(),
107 ALOGE("failed to remove fallthrough to %s for VPN netId %u", physicalInterface.c_str(),
115 int NetworkController::DelegateImpl::addFallthrough(const std::string& physicalInterface,
116 Permission permission) {
117 return modifyFallthrough(physicalInterface, permission, true);
120 int NetworkController::DelegateImpl::removeFallthrough(const std::string& physicalInterface,
121 Permission permission) {
122 return modifyFallthrough(physicalInterface, permission, false);
125 int NetworkController::DelegateImpl::modifyFallthrough(const std::string& physicalInterface,
126 Permission permission, bool add) {
127 for (const auto& entry : mNetworkController->mNetworks) {
128 if (entry.second->getType() == Network::VIRTUAL) {
129 if (int ret = modifyFallthrough(entry.first, physicalInterface, permission, add)) {
137 NetworkController::NetworkController() :
138 mDelegateImpl(new NetworkController::DelegateImpl(this)), mDefaultNetId(NETID_UNSET),
139 mProtectableUsers({AID_VPN}) {
140 mNetworks[LOCAL_NET_ID] = new LocalNetwork(LOCAL_NET_ID);
141 mNetworks[DUMMY_NET_ID] = new DummyNetwork(DUMMY_NET_ID);
144 unsigned NetworkController::getDefaultNetwork() const {
145 android::RWLock::AutoRLock lock(mRWLock);
146 return mDefaultNetId;
149 int NetworkController::setDefaultNetwork(unsigned netId) {
150 android::RWLock::AutoWLock lock(mRWLock);
152 if (netId == mDefaultNetId) {
156 if (netId != NETID_UNSET) {
157 Network* network = getNetworkLocked(netId);
159 ALOGE("no such netId %u", netId);
162 if (network->getType() != Network::PHYSICAL) {
163 ALOGE("cannot set default to non-physical network with netId %u", netId);
166 if (int ret = static_cast<PhysicalNetwork*>(network)->addAsDefault()) {
171 if (mDefaultNetId != NETID_UNSET) {
172 Network* network = getNetworkLocked(mDefaultNetId);
173 if (!network || network->getType() != Network::PHYSICAL) {
174 ALOGE("cannot find previously set default network with netId %u", mDefaultNetId);
177 if (int ret = static_cast<PhysicalNetwork*>(network)->removeAsDefault()) {
182 mDefaultNetId = netId;
186 uint32_t NetworkController::getNetworkForDns(unsigned* netId, uid_t uid) const {
187 android::RWLock::AutoRLock lock(mRWLock);
189 fwmark.protectedFromVpn = true;
190 fwmark.permission = PERMISSION_SYSTEM;
191 if (checkUserNetworkAccessLocked(uid, *netId) == 0) {
192 // If a non-zero NetId was explicitly specified, and the user has permission for that
193 // network, use that network's DNS servers. Do not fall through to the default network even
194 // if the explicitly selected network is a split tunnel VPN: the explicitlySelected bit
195 // ensures that the VPN fallthrough rule does not match.
196 fwmark.explicitlySelected = true;
198 // If the network is a VPN and it doesn't have DNS servers, use the default network's DNS
199 // servers (through the default network). Otherwise, the query is guaranteed to fail.
201 Network *network = getNetworkLocked(*netId);
202 if (network && network->getType() == Network::VIRTUAL &&
203 !static_cast<VirtualNetwork *>(network)->getHasDns()) {
204 *netId = mDefaultNetId;
207 // If the user is subject to a VPN and the VPN provides DNS servers, use those servers
208 // (possibly falling through to the default network if the VPN doesn't provide a route to
209 // them). Otherwise, use the default network's DNS servers.
210 VirtualNetwork* virtualNetwork = getVirtualNetworkForUserLocked(uid);
211 if (virtualNetwork && virtualNetwork->getHasDns()) {
212 *netId = virtualNetwork->getNetId();
214 // TODO: return an error instead of silently doing the DNS lookup on the wrong network.
216 *netId = mDefaultNetId;
219 fwmark.netId = *netId;
220 return fwmark.intValue;
223 // Returns the NetId that a given UID would use if no network is explicitly selected. Specifically,
224 // the VPN that applies to the UID if any; otherwise, the default network.
225 unsigned NetworkController::getNetworkForUser(uid_t uid) const {
226 android::RWLock::AutoRLock lock(mRWLock);
227 if (VirtualNetwork* virtualNetwork = getVirtualNetworkForUserLocked(uid)) {
228 return virtualNetwork->getNetId();
230 return mDefaultNetId;
233 // Returns the NetId that will be set when a socket connect()s. This is the bypassable VPN that
234 // applies to the user if any; otherwise, the default network.
236 // In general, we prefer to always set the default network's NetId in connect(), so that if the VPN
237 // is a split-tunnel and disappears later, the socket continues working (since the default network's
238 // NetId is still valid). Secure VPNs will correctly grab the socket's traffic since they have a
239 // high-priority routing rule that doesn't care what NetId the socket has.
241 // But bypassable VPNs have a very low priority rule, so we need to mark the socket with the
242 // bypassable VPN's NetId if we expect it to get any traffic at all. If the bypassable VPN is a
243 // split-tunnel, that's okay, because we have fallthrough rules that will direct the fallthrough
244 // traffic to the default network. But it does mean that if the bypassable VPN goes away (and thus
245 // the fallthrough rules also go away), the socket that used to fallthrough to the default network
246 // will stop working.
247 unsigned NetworkController::getNetworkForConnect(uid_t uid) const {
248 android::RWLock::AutoRLock lock(mRWLock);
249 VirtualNetwork* virtualNetwork = getVirtualNetworkForUserLocked(uid);
250 if (virtualNetwork && !virtualNetwork->isSecure()) {
251 return virtualNetwork->getNetId();
253 return mDefaultNetId;
256 void NetworkController::getNetworkContext(
257 unsigned netId, uid_t uid, struct android_net_context* netcontext) const {
258 struct android_net_context nc = {
260 .app_mark = MARK_UNSET,
262 .dns_mark = MARK_UNSET,
266 // |netId| comes directly (via dnsproxyd) from the value returned by netIdForResolv() in the
267 // client process. This value is nonzero iff.:
269 // 1. The app specified a netid/nethandle to a DNS resolution method such as:
270 // - [Java] android.net.Network#getAllByName()
271 // - [C/++] android_getaddrinfofornetwork()
272 // 2. The app specified a netid/nethandle to be used as a process default via:
273 // - [Java] android.net.ConnectivityManager#bindProcessToNetwork()
274 // - [C/++] android_setprocnetwork()
275 // 3. The app called android.net.ConnectivityManager#startUsingNetworkFeature().
277 // In all these cases (with the possible exception of #3), the right thing to do is to treat
278 // such cases as explicitlySelected.
279 const bool explicitlySelected = (nc.app_netid != NETID_UNSET);
280 if (!explicitlySelected) {
281 nc.app_netid = getNetworkForConnect(uid);
285 fwmark.netId = nc.app_netid;
286 fwmark.explicitlySelected = explicitlySelected;
287 fwmark.protectedFromVpn = canProtect(uid);
288 fwmark.permission = getPermissionForUser(uid);
289 nc.app_mark = fwmark.intValue;
291 nc.dns_mark = getNetworkForDns(&(nc.dns_netid), uid);
298 unsigned NetworkController::getNetworkForInterface(const char* interface) const {
299 android::RWLock::AutoRLock lock(mRWLock);
300 for (const auto& entry : mNetworks) {
301 if (entry.second->hasInterface(interface)) {
308 bool NetworkController::isVirtualNetwork(unsigned netId) const {
309 android::RWLock::AutoRLock lock(mRWLock);
310 Network* network = getNetworkLocked(netId);
311 return network && network->getType() == Network::VIRTUAL;
314 int NetworkController::createPhysicalNetwork(unsigned netId, Permission permission) {
315 if (!((MIN_NET_ID <= netId && netId <= MAX_NET_ID) ||
316 (MIN_OEM_ID <= netId && netId <= MAX_OEM_ID))) {
317 ALOGE("invalid netId %u", netId);
321 if (isValidNetwork(netId)) {
322 ALOGE("duplicate netId %u", netId);
326 PhysicalNetwork* physicalNetwork = new PhysicalNetwork(netId, mDelegateImpl);
327 if (int ret = physicalNetwork->setPermission(permission)) {
328 ALOGE("inconceivable! setPermission cannot fail on an empty network");
329 delete physicalNetwork;
333 android::RWLock::AutoWLock lock(mRWLock);
334 mNetworks[netId] = physicalNetwork;
338 int NetworkController::createVirtualNetwork(unsigned netId, bool hasDns, bool secure) {
339 if (!(MIN_NET_ID <= netId && netId <= MAX_NET_ID)) {
340 ALOGE("invalid netId %u", netId);
344 if (isValidNetwork(netId)) {
345 ALOGE("duplicate netId %u", netId);
349 android::RWLock::AutoWLock lock(mRWLock);
350 if (int ret = modifyFallthroughLocked(netId, true)) {
353 mNetworks[netId] = new VirtualNetwork(netId, hasDns, secure);
357 int NetworkController::destroyNetwork(unsigned netId) {
358 if (netId == LOCAL_NET_ID) {
359 ALOGE("cannot destroy local network");
362 if (!isValidNetwork(netId)) {
363 ALOGE("no such netId %u", netId);
367 // TODO: ioctl(SIOCKILLADDR, ...) to kill all sockets on the old network.
369 android::RWLock::AutoWLock lock(mRWLock);
370 Network* network = getNetworkLocked(netId);
372 // If we fail to destroy a network, things will get stuck badly. Therefore, unlike most of the
373 // other network code, ignore failures and attempt to clear out as much state as possible, even
374 // if we hit an error on the way. Return the first error that we see.
375 int ret = network->clearInterfaces();
377 if (mDefaultNetId == netId) {
378 if (int err = static_cast<PhysicalNetwork*>(network)->removeAsDefault()) {
379 ALOGE("inconceivable! removeAsDefault cannot fail on an empty network");
384 mDefaultNetId = NETID_UNSET;
385 } else if (network->getType() == Network::VIRTUAL) {
386 if (int err = modifyFallthroughLocked(netId, false)) {
392 mNetworks.erase(netId);
394 _resolv_delete_cache_for_net(netId);
398 int NetworkController::addInterfaceToNetwork(unsigned netId, const char* interface) {
399 if (!isValidNetwork(netId)) {
400 ALOGE("no such netId %u", netId);
404 unsigned existingNetId = getNetworkForInterface(interface);
405 if (existingNetId != NETID_UNSET && existingNetId != netId) {
406 ALOGE("interface %s already assigned to netId %u", interface, existingNetId);
410 android::RWLock::AutoWLock lock(mRWLock);
411 return getNetworkLocked(netId)->addInterface(interface);
414 int NetworkController::removeInterfaceFromNetwork(unsigned netId, const char* interface) {
415 if (!isValidNetwork(netId)) {
416 ALOGE("no such netId %u", netId);
420 android::RWLock::AutoWLock lock(mRWLock);
421 return getNetworkLocked(netId)->removeInterface(interface);
424 Permission NetworkController::getPermissionForUser(uid_t uid) const {
425 android::RWLock::AutoRLock lock(mRWLock);
426 return getPermissionForUserLocked(uid);
429 void NetworkController::setPermissionForUsers(Permission permission,
430 const std::vector<uid_t>& uids) {
431 android::RWLock::AutoWLock lock(mRWLock);
432 for (uid_t uid : uids) {
433 mUsers[uid] = permission;
437 int NetworkController::checkUserNetworkAccess(uid_t uid, unsigned netId) const {
438 android::RWLock::AutoRLock lock(mRWLock);
439 return checkUserNetworkAccessLocked(uid, netId);
442 int NetworkController::setPermissionForNetworks(Permission permission,
443 const std::vector<unsigned>& netIds) {
444 android::RWLock::AutoWLock lock(mRWLock);
445 for (unsigned netId : netIds) {
446 Network* network = getNetworkLocked(netId);
448 ALOGE("no such netId %u", netId);
451 if (network->getType() != Network::PHYSICAL) {
452 ALOGE("cannot set permissions on non-physical network with netId %u", netId);
456 if (int ret = static_cast<PhysicalNetwork*>(network)->setPermission(permission)) {
463 int NetworkController::addUsersToNetwork(unsigned netId, const UidRanges& uidRanges) {
464 android::RWLock::AutoWLock lock(mRWLock);
465 Network* network = getNetworkLocked(netId);
467 ALOGE("no such netId %u", netId);
470 if (network->getType() != Network::VIRTUAL) {
471 ALOGE("cannot add users to non-virtual network with netId %u", netId);
474 if (int ret = static_cast<VirtualNetwork*>(network)->addUsers(uidRanges, mProtectableUsers)) {
480 int NetworkController::removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges) {
481 android::RWLock::AutoWLock lock(mRWLock);
482 Network* network = getNetworkLocked(netId);
484 ALOGE("no such netId %u", netId);
487 if (network->getType() != Network::VIRTUAL) {
488 ALOGE("cannot remove users from non-virtual network with netId %u", netId);
491 if (int ret = static_cast<VirtualNetwork*>(network)->removeUsers(uidRanges,
492 mProtectableUsers)) {
498 int NetworkController::addRoute(unsigned netId, const char* interface, const char* destination,
499 const char* nexthop, bool legacy, uid_t uid) {
500 return modifyRoute(netId, interface, destination, nexthop, true, legacy, uid);
503 int NetworkController::removeRoute(unsigned netId, const char* interface, const char* destination,
504 const char* nexthop, bool legacy, uid_t uid) {
505 return modifyRoute(netId, interface, destination, nexthop, false, legacy, uid);
508 bool NetworkController::canProtect(uid_t uid) const {
509 android::RWLock::AutoRLock lock(mRWLock);
510 return ((getPermissionForUserLocked(uid) & PERMISSION_SYSTEM) == PERMISSION_SYSTEM) ||
511 mProtectableUsers.find(uid) != mProtectableUsers.end();
514 void NetworkController::allowProtect(const std::vector<uid_t>& uids) {
515 android::RWLock::AutoWLock lock(mRWLock);
516 mProtectableUsers.insert(uids.begin(), uids.end());
519 void NetworkController::denyProtect(const std::vector<uid_t>& uids) {
520 android::RWLock::AutoWLock lock(mRWLock);
521 for (uid_t uid : uids) {
522 mProtectableUsers.erase(uid);
526 void NetworkController::dump(DumpWriter& dw) {
527 android::RWLock::AutoRLock lock(mRWLock);
530 dw.println("NetworkController");
533 dw.println("Default network: %u", mDefaultNetId);
536 dw.println("Networks:");
538 for (const auto& i : mNetworks) {
539 Network* network = i.second;
540 dw.println(network->toString().c_str());
541 if (network->getType() == Network::PHYSICAL) {
543 Permission permission = reinterpret_cast<PhysicalNetwork*>(network)->getPermission();
544 dw.println("Required permission: %s", permissionToName(permission));
547 android::net::gCtls->resolverCtrl.dump(dw, i.first);
557 bool NetworkController::isValidNetwork(unsigned netId) const {
558 android::RWLock::AutoRLock lock(mRWLock);
559 return getNetworkLocked(netId);
562 Network* NetworkController::getNetworkLocked(unsigned netId) const {
563 auto iter = mNetworks.find(netId);
564 return iter == mNetworks.end() ? NULL : iter->second;
567 VirtualNetwork* NetworkController::getVirtualNetworkForUserLocked(uid_t uid) const {
568 for (const auto& entry : mNetworks) {
569 if (entry.second->getType() == Network::VIRTUAL) {
570 VirtualNetwork* virtualNetwork = static_cast<VirtualNetwork*>(entry.second);
571 if (virtualNetwork->appliesToUser(uid)) {
572 return virtualNetwork;
579 Permission NetworkController::getPermissionForUserLocked(uid_t uid) const {
580 auto iter = mUsers.find(uid);
581 if (iter != mUsers.end()) {
584 return uid < FIRST_APPLICATION_UID ? PERMISSION_SYSTEM : PERMISSION_NONE;
587 int NetworkController::checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const {
588 Network* network = getNetworkLocked(netId);
593 // If uid is INVALID_UID, this likely means that we were unable to retrieve the UID of the peer
594 // (using SO_PEERCRED). Be safe and deny access to the network, even if it's valid.
595 if (uid == INVALID_UID) {
598 Permission userPermission = getPermissionForUserLocked(uid);
599 if ((userPermission & PERMISSION_SYSTEM) == PERMISSION_SYSTEM) {
602 if (network->getType() == Network::VIRTUAL) {
603 return static_cast<VirtualNetwork*>(network)->appliesToUser(uid) ? 0 : -EPERM;
605 VirtualNetwork* virtualNetwork = getVirtualNetworkForUserLocked(uid);
606 if (virtualNetwork && virtualNetwork->isSecure() &&
607 mProtectableUsers.find(uid) == mProtectableUsers.end()) {
610 Permission networkPermission = static_cast<PhysicalNetwork*>(network)->getPermission();
611 return ((userPermission & networkPermission) == networkPermission) ? 0 : -EACCES;
614 int NetworkController::modifyRoute(unsigned netId, const char* interface, const char* destination,
615 const char* nexthop, bool add, bool legacy, uid_t uid) {
616 if (!isValidNetwork(netId)) {
617 ALOGE("no such netId %u", netId);
620 unsigned existingNetId = getNetworkForInterface(interface);
621 if (existingNetId == NETID_UNSET) {
622 ALOGE("interface %s not assigned to any netId", interface);
625 if (existingNetId != netId) {
626 ALOGE("interface %s assigned to netId %u, not %u", interface, existingNetId, netId);
630 RouteController::TableType tableType;
631 if (netId == LOCAL_NET_ID) {
632 tableType = RouteController::LOCAL_NETWORK;
634 if ((getPermissionForUser(uid) & PERMISSION_SYSTEM) == PERMISSION_SYSTEM) {
635 tableType = RouteController::LEGACY_SYSTEM;
637 tableType = RouteController::LEGACY_NETWORK;
640 tableType = RouteController::INTERFACE;
643 return add ? RouteController::addRoute(interface, destination, nexthop, tableType) :
644 RouteController::removeRoute(interface, destination, nexthop, tableType);
647 int NetworkController::modifyFallthroughLocked(unsigned vpnNetId, bool add) {
648 if (mDefaultNetId == NETID_UNSET) {
651 Network* network = getNetworkLocked(mDefaultNetId);
653 ALOGE("cannot find previously set default network with netId %u", mDefaultNetId);
656 if (network->getType() != Network::PHYSICAL) {
657 ALOGE("inconceivable! default network must be a physical network");
660 Permission permission = static_cast<PhysicalNetwork*>(network)->getPermission();
661 for (const auto& physicalInterface : network->getInterfaces()) {
662 if (int ret = mDelegateImpl->modifyFallthrough(vpnNetId, physicalInterface, permission,
670 int NetworkController::setMetricsReportingLevel(const int level) {
671 if (level < 0 || level > 1) {
672 ALOGE("Invalid reporting level %d", level);
675 mReportingLevel = level;
679 int NetworkController::getMetricsReportingLevel() const {
680 return mReportingLevel;