Add Windows and Mac network list implementation

chrome/browser/media/router/discovery/discovery_network_list_win.cc

 // Copyright (c) 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/media/router/discovery/discovery_network_list.h"
 
-// TODO(btolsch): Implement this for Windows.
+#include <winsock2.h>
+#include <ws2tcpip.h>
+
+#include <iphlpapi.h>  // NOLINT
+
+#include <windot11.h>  // NOLINT
+#include <wlanapi.h>   // NOLINT
+
+#include <algorithm>
+#include <utility>
+#include <vector>
+
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_number_conversions.h"
+
+namespace {
+
+void IfTable2Deleter(PMIB_IF_TABLE2 interface_table) {
+  if (interface_table) {
+    FreeMibTable(interface_table);
+  }
+}
+
+void WlanApiDeleter(void* p) {
+  if (p) {
+    WlanFreeMemory(p);
+  }
+}
+
+struct MAC {
+  MAC() : data{} {}
+  MAC(const uint8_t* src, ULONG length) : data{} { assign(src, length); }
+  void assign(const uint8_t* src, ULONG length) {
+    DCHECK_LE(length, 6UL);
+    memcpy(data, src, length);
+  }
+  bool operator==(const MAC& o) const { return memcmp(o.data, data, 6) == 0; }
+  uint8_t data[6];
+};
+
+std::vector<std::pair<GUID, MAC>> GetInterfaceGuidMap() {
+  PMIB_IF_TABLE2 interface_table_raw = nullptr;
+  auto result = GetIfTable2(&interface_table_raw);
+  if (result != ERROR_SUCCESS) {
+    DVLOG(2) << "GetIfTable2() failed";
+    return {};
+  }
+  auto interface_table =
+      std::unique_ptr<MIB_IF_TABLE2, decltype(&IfTable2Deleter)>(
+          interface_table_raw, IfTable2Deleter);
+
+  std::vector<std::pair<GUID, MAC>> guid_map;
+  guid_map.reserve(interface_table->NumEntries);
+  for (ULONG i = 0; i < interface_table->NumEntries; ++i) {
+    const auto* interface_row = &interface_table->Table[i];
+    guid_map.push_back(
+        std::make_pair(interface_row->InterfaceGuid,
+                       MAC{interface_row->PhysicalAddress,
+                           interface_row->PhysicalAddressLength}));
+  }
+
+  return guid_map;
+}
+
+std::vector<std::pair<MAC, std::string>> GetConnectionInfo() {
+  HANDLE client_handle = nullptr;
+  constexpr DWORD client_version = 2;
+  DWORD current_version = 0;
+
+  auto result =
+      WlanOpenHandle(client_version, nullptr, &current_version, &client_handle);
+  if (result != ERROR_SUCCESS) {
+    DVLOG(2) << "Failed to open Wlan client handle";
+    return {};
+  }
+
+  PWLAN_INTERFACE_INFO_LIST wlan_interface_list_raw = nullptr;
+  result = WlanEnumInterfaces(client_handle, nullptr, &wlan_interface_list_raw);
+  if (result != ERROR_SUCCESS) {
+    DVLOG(2) << "Failed to enumerate wireless interfaces";
+    return {};
+  }
+  auto wlan_interface_list =
+      std::unique_ptr<WLAN_INTERFACE_INFO_LIST, decltype(&WlanApiDeleter)>(
+          wlan_interface_list_raw, WlanApiDeleter);
+
+  auto guid_mac_map = GetInterfaceGuidMap();
+
+  std::vector<std::pair<MAC, std::string>> mac_ssid_map;
+  for (DWORD i = 0; i < wlan_interface_list->dwNumberOfItems; ++i) {
+    const auto* interface_info = &wlan_interface_list->InterfaceInfo[i];
+    MAC interface_mac;
+    bool found_mac = false;
+    for (const auto& guid_entry : guid_mac_map) {
+      if (guid_entry.first == interface_info->InterfaceGuid) {
+        interface_mac = guid_entry.second;
+        found_mac = true;
+        break;
+      }
+    }
+    if (!found_mac) {
+      continue;
+    }
+
+    WLAN_CONNECTION_ATTRIBUTES* connection_info = nullptr;
+    DWORD connection_info_size = 0;
+    result = WlanQueryInterface(
+        client_handle, &interface_info->InterfaceGuid,
+        wlan_intf_opcode_current_connection, nullptr, &connection_info_size,
+        reinterpret_cast<void**>(&connection_info), nullptr);
+    if (result != ERROR_SUCCESS) {
+      // We can't get the SSID for this interface so its network ID will
+      // fall back to its MAC address below.
+      DVLOG(2) << "Failed to get wireless connection info";
+      continue;
+    }
+    auto connection_attributes =
+        std::unique_ptr<WLAN_CONNECTION_ATTRIBUTES, decltype(&WlanApiDeleter)>(
+            connection_info, WlanApiDeleter);
+    const auto* ssid =
+        &connection_attributes->wlanAssociationAttributes.dot11Ssid;
+    mac_ssid_map.push_back(std::make_pair(
+        interface_mac,
+        std::string(reinterpret_cast<const char*>(&ssid->ucSSID[0]),
+                    ssid->uSSIDLength)));
+  }
+  return mac_ssid_map;
+}
+
+}  // namespace
+
 std::vector<DiscoveryNetworkInfo> GetDiscoveryNetworkInfoList() {
-  return std::vector<DiscoveryNetworkInfo>();
-}
+  // Max number of times to retry GetAdaptersAddresses due to
+  // ERROR_BUFFER_OVERFLOW. If GetAdaptersAddresses returns this indefinitely
+  // due to an unforseen reason, we don't want to be stuck in an endless loop.
+  static constexpr int kMaxGetAdaptersAddressTries = 10;
+  // Use an initial buffer size of 15KB, as recommended by MSDN. See:
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/aa365915(v=vs.85).aspx
+  static constexpr int kInitialBufferSize = 15000;
+  constexpr ULONG address_flags =  // TODO: include all interfaces flag?
+      GAA_FLAG_SKIP_UNICAST | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST |
+      GAA_FLAG_SKIP_DNS_SERVER;
+  std::vector<DiscoveryNetworkInfo> network_ids;
+
+  ULONG addresses_buffer_size = kInitialBufferSize;
+  char initial_buf[kInitialBufferSize];
+  std::unique_ptr<char[]> addresses_buffer;
+
+  PIP_ADAPTER_ADDRESSES adapter_addresses =
+      reinterpret_cast<PIP_ADAPTER_ADDRESSES>(initial_buf);
+  auto result = GetAdaptersAddresses(AF_UNSPEC, address_flags, nullptr,
+                                     adapter_addresses, &addresses_buffer_size);
+
+  for (int i = 1;
+       result == ERROR_BUFFER_OVERFLOW && i < kMaxGetAdaptersAddressTries;
+       ++i) {
+    addresses_buffer.reset(new char[addresses_buffer_size]);
+    adapter_addresses =
+        reinterpret_cast<PIP_ADAPTER_ADDRESSES>(addresses_buffer.get());
+    result = GetAdaptersAddresses(AF_UNSPEC, address_flags, nullptr,
+                                  adapter_addresses, &addresses_buffer_size);
+  }
+
+  if (result != NO_ERROR) {
+    return std::vector<DiscoveryNetworkInfo>();
+  }
+
+  auto mac_ssid_map = GetConnectionInfo();
+  for (const IP_ADAPTER_ADDRESSES* current_adapter = adapter_addresses;
+       current_adapter != nullptr; current_adapter = current_adapter->Next) {
+    if (current_adapter->OperStatus != IfOperStatusUp ||
+        (current_adapter->IfType != IF_TYPE_ETHERNET_CSMACD &&
+         current_adapter->IfType != IF_TYPE_IEEE80211)) {
+      continue;
+    }
+    std::string name(current_adapter->AdapterName);
+    // We have to use a slightly roundabout way to get the SSID for each
+    // adapter:
+    // - Enumerate wifi devices to get list of interface GUIDs.
+    // - Enumerate interfaces to get interface GUID -> physical address map.
+    // - Map interface GUIDs to SSID.
+    // - Use GUID -> MAC map to do MAC -> interface GUID  -> SSID.
+    // Although it's theoretically possible to have multiple interfaces per
+    // adapter, most wireless cards don't actually allow multiple
+    // managed-mode interfaces.  However, in the event that there really
+    // are multiple interfaces per adapter, we will simply choose the first
+    // one in this list.
+    if (current_adapter->IfType == IF_TYPE_IEEE80211) {
+      MAC adapter_mac(current_adapter->PhysicalAddress,
+                      current_adapter->PhysicalAddressLength);
+      bool found_ssid = false;
+      for (const auto& ssid_entry : mac_ssid_map) {
+        if (ssid_entry.first == adapter_mac) {
+          network_ids.push_back({name, ssid_entry.second});
+          found_ssid = true;
+          break;
+        }
+      }
+      if (found_ssid) {
+        continue;
+      }
+    }
+    network_ids.push_back(
+        {name, base::HexEncode(current_adapter->PhysicalAddress,
+                               current_adapter->PhysicalAddressLength)});
+  }
+
+  StableSortDiscoveryNetworkInfo(network_ids.begin(), network_ids.end());
+
+  return network_ids;
+}