shill/wifi/wifi_rf.cc

// Copyright 2022 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <linux/nl80211.h>

#include "shill/wifi/wifi_rf.h"

#include <chromeos/dbus/shill/dbus-constants.h>

namespace shill {

std::string WiFiBandName(WiFiBand band) {
  switch (band) {
    case WiFiBand::kLowBand:
      return kBand2GHz;
    case WiFiBand::kHighBand:
      return kBand5GHz;
    case WiFiBand::kAllBands:
      return kBandAll;
    case WiFiBand::kUnknownBand:
    default:
      return kBandUnknown;
  }
}

WiFiBand WiFiBandFromName(const std::string& name) {
  if (name == kBand2GHz) {
    return WiFiBand::kLowBand;
  } else if (name == kBand5GHz) {
    return WiFiBand::kHighBand;
  } else if (name == kBandAll) {
    return WiFiBand::kAllBands;
  } else {
    return WiFiBand::kUnknownBand;
  }
}

int WiFiBandToNl(WiFiBand band) {
  switch (band) {
    case WiFiBand::kLowBand:
      return NL80211_BAND_2GHZ;
    case WiFiBand::kHighBand:
      return NL80211_BAND_5GHZ;
    default:
      return -1;
  }
}

bool IsWiFiLimitedFreq(uint32_t freq) {
  if (freq > 2462 && freq <= 2495) {
    // Channel 12 and 13 should be avoided as it is only allowed in low power
    // operation. Channel 14 should be avoided as it only allows non-OFDM mode
    // in JP.
    return true;
  }

  if (freq > 5815) {
    // Wi-Fi use of U-NII-4 channels (5850MHz - 5925MHz) has been approved by
    // FCC and ETSI in late 2020.
    // https://www.fcc.gov/document/fcc-modernizes-59-ghz-band-improve-wi-fi-and-automotive-safety-0
    // Some device cannot detect these channels due to old hardware. Mask them
    // out to avoid compatibility issues. Also mask channel 165 (5815MHz -
    // 5835MHz) out as 40MHz or 80MHz channel width with channel 165 as primary
    // channel also extends to the U-NII-4 bands.
    return true;
  }

  return false;
}

}  // namespace shill