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      1 /*
      2  * Copyright (C) 2017 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 #include "common/libs/net/network_interface_manager.h"
     17 
     18 #include <arpa/inet.h>
     19 #include <linux/if_addr.h>
     20 #include <linux/if_link.h>
     21 #include <linux/netlink.h>
     22 #include <linux/rtnetlink.h>
     23 #include <net/if.h>
     24 
     25 #include <memory>
     26 
     27 #include "common/libs/glog/logging.h"
     28 #include "common/libs/net/network_interface.h"
     29 
     30 namespace cvd {
     31 namespace {
     32 NetlinkRequest BuildLinkRequest(
     33     const NetworkInterface& interface) {
     34   NetlinkRequest request(RTM_SETLINK, 0);
     35   request.AddIfInfo(interface.Index(), interface.IsOperational());
     36   if (!interface.Name().empty()) {
     37     request.AddString(IFLA_IFNAME, interface.Name());
     38   }
     39 
     40   return request;
     41 }
     42 
     43 NetlinkRequest BuildAddrRequest(
     44     const NetworkInterface& interface) {
     45   NetlinkRequest request(RTM_NEWADDR, 0);
     46   request.AddAddrInfo(interface.Index(), interface.PrefixLength());
     47   in_addr_t address{inet_addr(interface.Address().c_str())};
     48   request.AddInt32(IFA_LOCAL, address);
     49   request.AddInt32(IFA_ADDRESS, address);
     50   request.AddInt32(IFA_BROADCAST,
     51                     inet_addr(interface.BroadcastAddress().c_str()));
     52 
     53   return request;
     54 }
     55 }  // namespace
     56 
     57 std::unique_ptr<NetworkInterfaceManager> NetworkInterfaceManager::New(
     58     NetlinkClientFactory* nl_factory) {
     59   std::unique_ptr<NetworkInterfaceManager> mgr;
     60 
     61   if (nl_factory == NULL) {
     62     nl_factory = NetlinkClientFactory::Default();
     63   }
     64 
     65   auto client = nl_factory->New(NETLINK_ROUTE);
     66   if (client) {
     67     mgr.reset(new NetworkInterfaceManager(std::move(client)));
     68   }
     69 
     70   return mgr;
     71 }
     72 
     73 NetworkInterfaceManager::NetworkInterfaceManager(
     74     std::unique_ptr<NetlinkClient> nl_client)
     75     : nl_client_(std::move(nl_client)) {}
     76 
     77 std::unique_ptr<NetworkInterface> NetworkInterfaceManager::Open(
     78     const std::string& if_name, const std::string& if_name_alt) {
     79   std::unique_ptr<NetworkInterface> iface;
     80   // NOTE: do not replace this code with an IOCTL call.
     81   // On SELinux enabled Androids, RILD is not permitted to execute an IOCTL
     82   // and this call will fail.
     83   int32_t index = if_nametoindex(if_name.c_str());
     84   if (index == 0) {
     85     // Try the alternate name. This will be renamed to our preferred name
     86     // by the kernel, because we specify IFLA_IFNAME, but open by index.
     87     LOG(ERROR) << "Failed to get interface (" << if_name << ") index, "
     88                << "trying alternate.";
     89     index = if_nametoindex(if_name_alt.c_str());
     90     if (index == 0) {
     91       LOG(ERROR) << "Failed to get interface (" << if_name_alt << ") index.";
     92       return iface;
     93     }
     94   }
     95 
     96   iface.reset(new NetworkInterface(index));
     97   return iface;
     98 }
     99 
    100 bool NetworkInterfaceManager::ApplyChanges(const NetworkInterface& iface) {
    101   if (!nl_client_->Send(BuildLinkRequest(iface))) return false;
    102   // Terminate immediately if interface is down.
    103   if (!iface.IsOperational()) return true;
    104   return nl_client_->Send(BuildAddrRequest(iface));
    105 }
    106 
    107 }  // namespace cvd
    108