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/*
* Copyright (C) 2014 The 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.
*/
// THREAD-SAFETY
// -------------
// The methods in this file are called from multiple threads (from CommandListener, FwmarkServer
// and DnsProxyListener). So, all accesses to shared state are guarded by a lock.
//
// In some cases, a single non-const method acquires and releases the lock several times, like so:
// if (isValidNetwork(...)) { // isValidNetwork() acquires and releases the lock.
// setDefaultNetwork(...); // setDefaultNetwork() also acquires and releases the lock.
//
// It might seem that this allows races where the state changes between the two statements, but in
// fact there are no races because:
// 1. This pattern only occurs in non-const methods (i.e., those that mutate state).
// 2. Only CommandListener calls these non-const methods. The others call only const methods.
// 3. CommandListener only processes one command at a time. I.e., it's serialized.
// Thus, no other mutation can occur in between the two statements above.
#include "NetworkController.h"
#include "PhysicalNetwork.h"
#include "RouteController.h"
#include "VirtualNetwork.h"
#define LOG_TAG "Netd"
#include "log/log.h"
#include "resolv_netid.h"
namespace {
// Keep these in sync with ConnectivityService.java.
const unsigned MIN_NET_ID = 10;
const unsigned MAX_NET_ID = 65535;
} // namespace
NetworkController::NetworkController() : mDefaultNetId(NETID_UNSET) {
}
unsigned NetworkController::getDefaultNetwork() const {
android::RWLock::AutoRLock lock(mRWLock);
return mDefaultNetId;
}
int NetworkController::setDefaultNetwork(unsigned netId) {
android::RWLock::AutoWLock lock(mRWLock);
if (netId == mDefaultNetId) {
return 0;
}
if (netId != NETID_UNSET) {
Network* network = getNetworkLocked(netId);
if (!network || network->getType() != Network::PHYSICAL) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
if (int ret = static_cast<PhysicalNetwork*>(network)->addAsDefault()) {
return ret;
}
}
if (mDefaultNetId != NETID_UNSET) {
Network* network = getNetworkLocked(mDefaultNetId);
if (!network || network->getType() != Network::PHYSICAL) {
ALOGE("cannot find previously set default network with netId %u", mDefaultNetId);
return -ESRCH;
}
if (int ret = static_cast<PhysicalNetwork*>(network)->removeAsDefault()) {
return ret;
}
}
mDefaultNetId = netId;
return 0;
}
bool NetworkController::setNetworkForUidRange(uid_t uidStart, uid_t uidEnd, unsigned netId,
bool forwardDns) {
if (uidStart > uidEnd || !isValidNetwork(netId)) {
errno = EINVAL;
return false;
}
android::RWLock::AutoWLock lock(mRWLock);
for (UidEntry& entry : mUidMap) {
if (entry.uidStart == uidStart && entry.uidEnd == uidEnd && entry.netId == netId) {
entry.forwardDns = forwardDns;
return true;
}
}
mUidMap.push_front(UidEntry(uidStart, uidEnd, netId, forwardDns));
return true;
}
bool NetworkController::clearNetworkForUidRange(uid_t uidStart, uid_t uidEnd, unsigned netId) {
if (uidStart > uidEnd || !isValidNetwork(netId)) {
errno = EINVAL;
return false;
}
android::RWLock::AutoWLock lock(mRWLock);
for (auto iter = mUidMap.begin(); iter != mUidMap.end(); ++iter) {
if (iter->uidStart == uidStart && iter->uidEnd == uidEnd && iter->netId == netId) {
mUidMap.erase(iter);
return true;
}
}
errno = ENOENT;
return false;
}
unsigned NetworkController::getNetwork(uid_t uid, unsigned requestedNetId, bool forDns) const {
android::RWLock::AutoRLock lock(mRWLock);
for (const UidEntry& entry : mUidMap) {
if (entry.uidStart <= uid && uid <= entry.uidEnd) {
if (forDns && !entry.forwardDns) {
break;
}
return entry.netId;
}
}
return getNetworkLocked(requestedNetId) ? requestedNetId : mDefaultNetId;
}
unsigned NetworkController::getNetworkId(const char* interface) const {
android::RWLock::AutoRLock lock(mRWLock);
for (const auto& entry : mNetworks) {
if (entry.second->hasInterface(interface)) {
return entry.first;
}
}
return NETID_UNSET;
}
bool NetworkController::isValidNetwork(unsigned netId) const {
android::RWLock::AutoRLock lock(mRWLock);
return getNetworkLocked(netId);
}
int NetworkController::createNetwork(unsigned netId, Permission permission) {
if (netId < MIN_NET_ID || netId > MAX_NET_ID) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
if (isValidNetwork(netId)) {
ALOGE("duplicate netId %u", netId);
return -EEXIST;
}
PhysicalNetwork* physicalNetwork = new PhysicalNetwork(netId);
if (int ret = physicalNetwork->setPermission(permission)) {
ALOGE("inconceivable! setPermission cannot fail on an empty network");
delete physicalNetwork;
return ret;
}
android::RWLock::AutoWLock lock(mRWLock);
mNetworks[netId] = physicalNetwork;
return 0;
}
int NetworkController::createVpn(unsigned netId) {
if (netId < MIN_NET_ID || netId > MAX_NET_ID) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
if (isValidNetwork(netId)) {
ALOGE("duplicate netId %u", netId);
return -EEXIST;
}
android::RWLock::AutoWLock lock(mRWLock);
mNetworks[netId] = new VirtualNetwork(netId);
return 0;
}
int NetworkController::destroyNetwork(unsigned netId) {
if (!isValidNetwork(netId)) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
// TODO: ioctl(SIOCKILLADDR, ...) to kill all sockets on the old network.
android::RWLock::AutoWLock lock(mRWLock);
Network* network = getNetworkLocked(netId);
if (int ret = network->clearInterfaces()) {
return ret;
}
if (mDefaultNetId == netId) {
if (int ret = static_cast<PhysicalNetwork*>(network)->removeAsDefault()) {
ALOGE("inconceivable! removeAsDefault cannot fail on an empty network");
return ret;
}
mDefaultNetId = NETID_UNSET;
}
mNetworks.erase(netId);
delete network;
_resolv_delete_cache_for_net(netId);
return 0;
}
int NetworkController::addInterfaceToNetwork(unsigned netId, const char* interface) {
if (!isValidNetwork(netId)) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
unsigned existingNetId = getNetworkId(interface);
if (existingNetId != NETID_UNSET && existingNetId != netId) {
ALOGE("interface %s already assigned to netId %u", interface, existingNetId);
return -EBUSY;
}
android::RWLock::AutoWLock lock(mRWLock);
return getNetworkLocked(netId)->addInterface(interface);
}
int NetworkController::removeInterfaceFromNetwork(unsigned netId, const char* interface) {
if (!isValidNetwork(netId)) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
android::RWLock::AutoWLock lock(mRWLock);
return getNetworkLocked(netId)->removeInterface(interface);
}
Permission NetworkController::getPermissionForUser(uid_t uid) const {
android::RWLock::AutoRLock lock(mRWLock);
auto iter = mUsers.find(uid);
return iter == mUsers.end() ? PERMISSION_NONE : iter->second;
}
void NetworkController::setPermissionForUsers(Permission permission,
const std::vector<uid_t>& uids) {
android::RWLock::AutoWLock lock(mRWLock);
for (uid_t uid : uids) {
if (permission == PERMISSION_NONE) {
mUsers.erase(uid);
} else {
mUsers[uid] = permission;
}
}
}
// TODO: Handle VPNs.
bool NetworkController::isUserPermittedOnNetwork(uid_t uid, unsigned netId) const {
android::RWLock::AutoRLock lock(mRWLock);
auto userIter = mUsers.find(uid);
Permission userPermission = (userIter == mUsers.end() ? PERMISSION_NONE : userIter->second);
Network* network = getNetworkLocked(netId);
if (!network || network->getType() != Network::PHYSICAL) {
return false;
}
Permission networkPermission = static_cast<PhysicalNetwork*>(network)->getPermission();
return (userPermission & networkPermission) == networkPermission;
}
int NetworkController::setPermissionForNetworks(Permission permission,
const std::vector<unsigned>& netIds) {
android::RWLock::AutoWLock lock(mRWLock);
for (unsigned netId : netIds) {
Network* network = getNetworkLocked(netId);
if (!network || network->getType() != Network::PHYSICAL) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
// TODO: ioctl(SIOCKILLADDR, ...) to kill socets on the network that don't have permission.
if (int ret = static_cast<PhysicalNetwork*>(network)->setPermission(permission)) {
return ret;
}
}
return 0;
}
int NetworkController::addUsersToNetwork(unsigned netId, const UidRanges& uidRanges) {
android::RWLock::AutoWLock lock(mRWLock);
Network* network = getNetworkLocked(netId);
if (!network || network->getType() != Network::VIRTUAL) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
if (int ret = static_cast<VirtualNetwork*>(network)->addUsers(uidRanges)) {
return ret;
}
return 0;
}
int NetworkController::removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges) {
android::RWLock::AutoWLock lock(mRWLock);
Network* network = getNetworkLocked(netId);
if (!network || network->getType() != Network::VIRTUAL) {
ALOGE("invalid netId %u", netId);
return -EINVAL;
}
if (int ret = static_cast<VirtualNetwork*>(network)->removeUsers(uidRanges)) {
return ret;
}
return 0;
}
int NetworkController::addRoute(unsigned netId, const char* interface, const char* destination,
const char* nexthop, bool legacy, uid_t uid) {
return modifyRoute(netId, interface, destination, nexthop, true, legacy, uid);
}
int NetworkController::removeRoute(unsigned netId, const char* interface, const char* destination,
const char* nexthop, bool legacy, uid_t uid) {
return modifyRoute(netId, interface, destination, nexthop, false, legacy, uid);
}
void NetworkController::allowProtect(const std::vector<uid_t>& uids) {
android::RWLock::AutoWLock lock(mRWLock);
mProtectableUsers.insert(uids.begin(), uids.end());
}
void NetworkController::denyProtect(const std::vector<uid_t>& uids) {
android::RWLock::AutoWLock lock(mRWLock);
for (uid_t uid : uids) {
mProtectableUsers.erase(uid);
}
}
Network* NetworkController::getNetworkLocked(unsigned netId) const {
auto iter = mNetworks.find(netId);
return iter == mNetworks.end() ? NULL : iter->second;
}
int NetworkController::modifyRoute(unsigned netId, const char* interface, const char* destination,
const char* nexthop, bool add, bool legacy, uid_t uid) {
unsigned existingNetId = getNetworkId(interface);
if (netId == NETID_UNSET || existingNetId != netId) {
ALOGE("interface %s assigned to netId %u, not %u", interface, existingNetId, netId);
return -ENOENT;
}
RouteController::TableType tableType;
if (legacy) {
if (getPermissionForUser(uid) & PERMISSION_CONNECTIVITY_INTERNAL) {
tableType = RouteController::PRIVILEGED_LEGACY;
} else {
tableType = RouteController::LEGACY;
}
} else {
tableType = RouteController::INTERFACE;
}
return add ? RouteController::addRoute(interface, destination, nexthop, tableType) :
RouteController::removeRoute(interface, destination, nexthop, tableType);
}
NetworkController::UidEntry::UidEntry(uid_t uidStart, uid_t uidEnd, unsigned netId,
bool forwardDns) :
uidStart(uidStart), uidEnd(uidEnd), netId(netId), forwardDns(forwardDns) {
}