1 files changed, 247 insertions, 0 deletions
diff --git a/toolkit/system/windowsDHCPClient/DHCPUtils.cpp b/toolkit/system/windowsDHCPClient/DHCPUtils.cpp
new file mode 100644
index 0000000000..956c2adbf0
--- /dev/null
+++ b/toolkit/system/windowsDHCPClient/DHCPUtils.cpp
@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DHCPUtils.h"
+#include <vector>
+#include "mozilla/Logging.h"
+#include "nsString.h"
+
+#define MOZ_WORKING_BUFFER_SIZE_NETWORK_ADAPTERS 15000
+#define MOZ_WORKING_BUFFER_SIZE_DHCP_PARAMS 1000
+#define MOZ_MAX_TRIES 3
+namespace mozilla {
+namespace toolkit {
+namespace system {
+namespace windowsDHCPClient {
+
+//
+// The comments on this page reference the following Microsoft documentation
+// pages (both retrieved 2017-06-27)
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365915(v=vs.85).aspx
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363298(v=vs.85).aspx
+mozilla::LazyLogModule gDhcpUtilsLog("dhcpUtils");
+
+#undef LOG
+#define LOG(args) MOZ_LOG(gDhcpUtilsLog, LogLevel::Debug, args)
+
+bool IsCurrentAndHasDHCP(PIP_ADAPTER_ADDRESSES aAddresses) {
+  return aAddresses->OperStatus == 1 &&
+         (aAddresses->Dhcpv4Server.iSockaddrLength ||
+          aAddresses->Dhcpv6Server.iSockaddrLength);
+}
+
+nsresult GetActiveDHCPNetworkAdapterName(
+    nsACString& aNetworkAdapterName,
+    WindowsNetworkFunctionsWrapper* aWindowsNetworkFunctionsWrapper) {
+  /* Declare and initialize variables */
+
+  uint32_t dwRetVal = 0;
+  nsresult rv = NS_ERROR_FAILURE;
+
+  // Set the flags to pass to GetAdaptersAddresses
+  uint32_t flags = GAA_FLAG_INCLUDE_PREFIX;
+
+  // default to unspecified address family (both)
+  uint32_t family = AF_UNSPEC;
+
+  // Allocate a 15 KB buffer to start with.
+  uint32_t outBufLen = MOZ_WORKING_BUFFER_SIZE_NETWORK_ADAPTERS;
+  uint32_t iterations = 0;
+
+  aNetworkAdapterName.Truncate();
+
+  // Now we try calling the GetAdaptersAddresses method until the return value
+  // is not ERROR_BUFFER_OVERFLOW. According to [1]
+  //
+  //
+  // > When the return value is ERROR_BUFFER_OVERFLOW, the SizePointer parameter
+  // returned > points to the required size of the buffer to hold the adapter
+  // information. > Note that it is possible for the buffer size required for
+  // the IP_ADAPTER_ADDRESSES > structures pointed to by the AdapterAddresses
+  // parameter to change between > subsequent calls to the GetAdaptersAddresses
+  // function if an adapter address > is added or removed. However, this method
+  // of using the GetAdaptersAddresses > function is strongly discouraged. This
+  // method requires calling the > GetAdaptersAddresses function multiple times.
+  // >
+  // > The recommended method of calling the GetAdaptersAddresses function is
+  // > to pre-allocate a 15KB working buffer pointed to by the AdapterAddresses
+  // parameter. > On typical computers, this dramatically reduces the chances
+  // that the > GetAdaptersAddresses function returns ERROR_BUFFER_OVERFLOW,
+  // which would require > calling GetAdaptersAddresses function multiple times.
+  //
+  //
+  // The possibility of the buffer size changing between calls to
+  // GetAdaptersAddresses is why we allow the following code to be called
+  // several times, rather than just the two that would be neccessary if we
+  // could rely on the value returned in outBufLen being the true size needed.
+
+  std::vector<IP_ADAPTER_ADDRESSES> pAddresses;
+  do {
+    // resize outBufLen up to the next multiple of sizeof(IP_ADAPTER_ADDRESSES)
+    outBufLen = ((outBufLen + sizeof(IP_ADAPTER_ADDRESSES) - 1) /
+                 sizeof(IP_ADAPTER_ADDRESSES)) *
+                sizeof(IP_ADAPTER_ADDRESSES);
+    pAddresses.resize(outBufLen / sizeof(IP_ADAPTER_ADDRESSES));
+    LOG(
+        ("Trying GetAdaptersAddresses with pAddresses sized to %zu and buffer "
+         "length of %d",
+         pAddresses.size(), outBufLen));
+
+    dwRetVal = aWindowsNetworkFunctionsWrapper->GetAdaptersAddressesWrapped(
+        family, flags, nullptr, pAddresses.data(), (PULONG)&outBufLen);
+
+    if (dwRetVal == ERROR_BUFFER_OVERFLOW) {
+      iterations++;
+    }
+  } while (dwRetVal == ERROR_BUFFER_OVERFLOW && iterations < MOZ_MAX_TRIES);
+
+  switch (dwRetVal) {
+    case NO_ERROR: {
+      // set default return value if we don't find a suitable network adapter
+      rv = NS_ERROR_NOT_AVAILABLE;
+      PIP_ADAPTER_ADDRESSES pCurrAddresses = pAddresses.data();
+      while (pCurrAddresses) {
+        if (IsCurrentAndHasDHCP(pCurrAddresses)) {
+          rv = NS_OK;
+          aNetworkAdapterName.Assign(pCurrAddresses->AdapterName);
+          break;
+        }
+        pCurrAddresses = pCurrAddresses->Next;
+      }
+    } break;
+    case ERROR_NO_DATA:
+      rv = NS_ERROR_NOT_AVAILABLE;
+      break;
+    default:
+      MOZ_LOG(gDhcpUtilsLog, mozilla::LogLevel::Warning,
+              ("GetAdaptersAddresses returned %d", dwRetVal));
+      rv = NS_ERROR_FAILURE;
+      break;
+  }
+  return rv;
+}
+
+DWORD
+IterateDHCPInformRequestsUntilBufferLargeEnough(
+    DHCPCAPI_PARAMS& aDhcpRequestedOptionParams,
+    wchar_t* aWideNetworkAdapterName, std::vector<char>& aBuffer,
+    WindowsNetworkFunctionsWrapper* aWindowsNetworkFunctionsWrapper) {
+  uint32_t iterations = 0;
+  uint32_t outBufLen = MOZ_WORKING_BUFFER_SIZE_DHCP_PARAMS;
+
+  DHCPCAPI_PARAMS_ARRAY RequestParams = {1,  // only one option to request
+                                         &aDhcpRequestedOptionParams};
+
+  // According to [2],
+  // the following is for 'Optional data to be requested,
+  // in addition to the data requested in the RecdParams array.'
+  // We are not requesting anything in addition, so this is empty.
+  DHCPCAPI_PARAMS_ARRAY SendParams = {0, nullptr};
+
+  DWORD winAPIResponse;
+  // Now we try calling the DHCPRequestParams method until the return value
+  // is not ERROR_MORE_DATA. According to [2]:
+  //
+  //
+  // > Note that the required size of Buffer may increase during the time that
+  // elapses > between the initial function call's return and a subsequent call;
+  // > therefore, the required size of Buffer (indicated in pSize)
+  // > provides an indication of the approximate size required of Buffer,
+  // > rather than guaranteeing that subsequent calls will return successfully
+  // > if Buffer is set to the size indicated in pSize.
+  //
+  //
+  // This is why we allow this DHCPRequestParams to be called several times,
+  // rather than just the two that would be neccessary if we could rely on the
+  // value returned in outBufLen being the true size needed.
+  do {
+    aBuffer.resize(outBufLen);
+
+    winAPIResponse = aWindowsNetworkFunctionsWrapper->DhcpRequestParamsWrapped(
+        DHCPCAPI_REQUEST_SYNCHRONOUS,  // Flags
+        nullptr,                       // Reserved
+        aWideNetworkAdapterName,       // Adapter Name
+        nullptr,                       // not using class id
+        SendParams,                    // sent parameters
+        RequestParams,                 // requesting params
+        (PBYTE)aBuffer.data(),         // buffer for the output of RequestParams
+        (PULONG)&outBufLen,            // buffer size
+        nullptr  // Request ID for persistent requests - not needed here
+    );
+
+    if (winAPIResponse == ERROR_MORE_DATA) {
+      iterations++;
+    }
+  } while (winAPIResponse == ERROR_MORE_DATA && iterations < MOZ_MAX_TRIES);
+  return winAPIResponse;
+}
+
+nsresult RetrieveOption(
+    const nsACString& aAdapterName, uint8_t aOption,
+    std::vector<char>& aOptionValueBuf, uint32_t* aOptionSize,
+    WindowsNetworkFunctionsWrapper* aWindowsNetworkFunctionsWrapper) {
+  nsresult rv;
+  nsAutoString wideNetworkAdapterName = NS_ConvertUTF8toUTF16(aAdapterName);
+
+  DHCPCAPI_PARAMS DhcpRequestedOptionParams = {
+      0,        //  Flags - Reserved, must be set to zero [2]
+      aOption,  // OptionId
+      false,    // whether this is vendor specific - let's assume not
+      nullptr,  // data filled in on return
+      0         // nBytes used by return data
+  };
+
+  std::vector<char> tmpBuffer(
+      MOZ_WORKING_BUFFER_SIZE_DHCP_PARAMS);  // a buffer for the DHCP response
+                                             // object
+  DWORD winAPIResponse = IterateDHCPInformRequestsUntilBufferLargeEnough(
+      DhcpRequestedOptionParams, wideNetworkAdapterName.get(), tmpBuffer,
+      aWindowsNetworkFunctionsWrapper);
+
+  switch (winAPIResponse) {
+    case NO_ERROR: {
+      if (DhcpRequestedOptionParams.nBytesData == 0) {
+        *aOptionSize = 0;
+        rv = NS_ERROR_NOT_AVAILABLE;
+        break;
+      }
+
+      if (*aOptionSize >= DhcpRequestedOptionParams.nBytesData) {
+        rv = NS_OK;
+      } else {
+        rv = NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+      }
+
+      uint32_t actualSizeReturned =
+          *aOptionSize > DhcpRequestedOptionParams.nBytesData
+              ? DhcpRequestedOptionParams.nBytesData
+              : *aOptionSize;
+
+      memcpy(aOptionValueBuf.data(), DhcpRequestedOptionParams.Data,
+             actualSizeReturned);
+      *aOptionSize = DhcpRequestedOptionParams.nBytesData;
+      break;
+    }
+    case ERROR_INVALID_PARAMETER:
+      MOZ_LOG(gDhcpUtilsLog, mozilla::LogLevel::Warning,
+              ("RetrieveOption returned %lu (ERROR_INVALID_PARAMETER) when "
+               "option %d requested",
+               winAPIResponse, aOption));
+      rv = NS_ERROR_INVALID_ARG;
+      break;
+    default:
+      MOZ_LOG(gDhcpUtilsLog, mozilla::LogLevel::Warning,
+              ("RetrieveOption returned %lu when option %d requested",
+               winAPIResponse, aOption));
+      rv = NS_ERROR_FAILURE;
+  }
+  return rv;
+}
+
+}  // namespace windowsDHCPClient
+}  // namespace system
+}  // namespace toolkit
+}  // namespace mozilla