// Copyright 2023 The Chromium Authors

//

// 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

//

//     https://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.

#include "ip_util.h"

BSSL_NAMESPACE_BEGIN

bool IsValidNetmask(der::Input mask) {

  if (mask.size() != kIPv4AddressSize && mask.size() != kIPv6AddressSize) {

    return false;

  }

  for (size_t i = 0; i < mask.size(); i++) {

    uint8_t b = mask[i];

    if (b != 0xff) {

      // b must be all ones followed by all zeros, so ~b must be all zeros

      // followed by all ones.

      uint8_t inv = ~b;

      if ((inv & (inv + 1)) != 0) {

        return false;

      }

      // The remaining bytes must be all zeros.

      for (size_t j = i + 1; j < mask.size(); j++) {

        if (mask[j] != 0) {

          return false;

        }

      }

      return true;

    }

  }

  return true;

}

bool IPAddressMatchesWithNetmask(der::Input addr1, der::Input addr2,

                                 der::Input mask) {

  if (addr1.size() != addr2.size() || addr1.size() != mask.size()) {

    return false;

  }

  for (size_t i = 0; i < addr1.size(); i++) {

    if ((addr1[i] & mask[i]) != (addr2[i] & mask[i])) {

      return false;

    }

  }

  return true;

}

BSSL_NAMESPACE_END