lib/wlan/mlme/client/bss.cpp - garnet - Git at Google

 // Copyright 2017 The Fuchsia 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 <wlan/mlme/client/bss.h>

 #include <wlan/common/channel.h>

 #include <string>

 namespace wlan {

 namespace wlan_mlme = ::fuchsia::wlan::mlme;

 // TODO(NET-500): This file needs some clean-up.

 zx_status_t Bss::ProcessBeacon(const Beacon& beacon, size_t frame_len,
                                const wlan_rx_info_t* rx_info) {
     if (!IsBeaconValid(beacon)) { return ZX_ERR_INTERNAL; }

     Renew(beacon, rx_info);

     if (!HasBeaconChanged(beacon, frame_len)) {
         // If unchanged, it is sufficient to renew the BSS. Bail out.
         return ZX_OK;
     }

     if (bcn_len_ != 0) {
         // TODO(porce): Identify varying IE, and do IE-by-IE comparison.
         // BSS had been discovered, but the beacon changed.
         // Suspicious situation. Consider Deauth if in assoc.
         debugbcn("BSSID %s beacon change detected. (len %zu -> %zu)\n", bssid_.ToString().c_str(),
                  bcn_len_, frame_len);
     }

     auto status = Update(beacon, frame_len);
     if (status != ZX_OK) {
         debugbcn("BSSID %s failed to update its BSS object: (%d)\n", bssid_.ToString().c_str(),
                  status);

         return status;
     }

     return ZX_OK;
 }

 std::string Bss::ToString() const {
     // TODO(porce): Convert to finspect Describe()
     char buf[1024];
     snprintf(
         buf, sizeof(buf), "BSSID %s Infra %s  RSSI %3d  Country %3s Channel %4s Cap %04x SSID [%s]",
         bssid_.ToString().c_str(), GetBssType() == wlan_mlme::BSSTypes::INFRASTRUCTURE ? "Y" : "N",
         rssi_dbm_.val, country_.c_str(), common::ChanStr(bcn_rx_chan_).c_str(), cap_.val(),
         SsidToString().c_str());
     return std::string(buf);
 }

 bool Bss::IsBeaconValid(const Beacon& beacon) const {
     // TODO(porce): Place holder. Add sanity logics.

     if (timestamp_ > beacon.timestamp) {
         // Suspicious. Wrap around?
         // TODO(porce): deauth if the client was in association.
     }

     // TODO(porce): Size check.
     // Note: Some beacons in 5GHz may not include DSSS Parameter Set IE

     return true;
 }

 void Bss::Renew(const Beacon& beacon, const wlan_rx_info_t* rx_info) {
     timestamp_ = beacon.timestamp;

     // TODO(porce): Take a deep look. Which resolution do we want to track?
     ts_refreshed_ = zx::clock::get(ZX_CLOCK_UTC);

     // Radio statistics.
     if (rx_info == nullptr) return;

     bcn_rx_chan_ = rx_info->chan;

     // If the latest beacons lack measurements, keep the last report.
     // TODO(NET-856): Change DDK wlan_rx_info_t and do translation in the vendor device driver.
     if (rx_info->valid_fields & WLAN_RX_INFO_VALID_RSSI) { rssi_dbm_.val = rx_info->rssi_dbm; }
     if (rx_info->valid_fields & WLAN_RX_INFO_VALID_RCPI) { rcpi_dbmh_.val = rx_info->rcpi_dbmh; }
     if (rx_info->valid_fields & WLAN_RX_INFO_VALID_SNR) { rsni_dbh_.val = rx_info->snr_dbh; }
 }

 bool Bss::HasBeaconChanged(const Beacon& beacon, size_t frame_len) const {
     // Test changes in beacon, except for the timestamp field.
     if (frame_len != bcn_len_) { return true; }
     auto sig = GetBeaconSignature(beacon, frame_len);
     if (sig != bcn_hash_) { return true; }
     return false;
 }

 zx_status_t Bss::Update(const Beacon& beacon, size_t frame_len) {
     // To be used to detect a change in Beacon.
     bcn_len_ = frame_len;
     bcn_hash_ = GetBeaconSignature(beacon, frame_len);

     // Fields that are always present.
     bcn_interval_ = beacon.beacon_interval;
     cap_ = beacon.cap;

     // IE's.
     auto ie_chains = beacon.elements;
     auto ie_chains_len = frame_len - sizeof(Beacon);  // Subtract the beacon header len.

     ZX_DEBUG_ASSERT(ie_chains != nullptr);
     ZX_DEBUG_ASSERT(ie_chains_len <= frame_len);
     return ParseIE(ie_chains, ie_chains_len);
 }

 zx_status_t Bss::ParseIE(const uint8_t* ie_chains, size_t ie_chains_len) {
     ElementReader reader(ie_chains, ie_chains_len);

     debugbcn("Parsing IEs for BSSID %s\n", bssid_.ToString().c_str());
     uint8_t ie_cnt = 0;
     uint8_t ie_unparsed_cnt = 0;

     has_dsss_param_set_chan_ = false;

     char dbgmsghdr[128];
     while (reader.is_valid()) {
         ie_cnt++;

         const ElementHeader* hdr = reader.peek();
         if (hdr == nullptr) break;

         // TODO(porce): Process HT Capabilities IE's HT Capabilites Info to get CBW announcement.

         snprintf(dbgmsghdr, sizeof(dbgmsghdr), "  IE %3u (Len %3u): ", hdr->id, hdr->len);
         switch (hdr->id) {
         case element_id::kSsid: {
             auto ie = reader.read<SsidElement>();
             if (ie == nullptr) {
                 debugbcn("%s Failed to parse\n", dbgmsghdr);
                 return ZX_ERR_INTERNAL;
             }

             ssid_len_ = ie->hdr.len;
             memcpy(ssid_, ie->ssid, ssid_len_);

             debugbcn("%s SSID: [%s]\n", dbgmsghdr, SsidToString().c_str());
             break;
         }
         case element_id::kSuppRates: {
             auto ie = reader.read<SupportedRatesElement>();
             if (ie == nullptr) {
                 debugbcn("%s Failed to parse\n", dbgmsghdr);
                 return ZX_ERR_INTERNAL;
             }

             for (uint8_t idx = 0; idx < ie->hdr.len; idx++) {
                 supported_rates_.push_back(ie->rates[idx]);
             }
             debugbcn("%s Supported rates: %s\n", dbgmsghdr, SupportedRatesToString().c_str());
             break;
         }
         case element_id::kDsssParamSet: {
             auto ie = reader.read<DsssParamSetElement>();
             if (ie == nullptr) {
                 debugbcn("%s Failed to parse\n", dbgmsghdr);
                 return ZX_ERR_INTERNAL;
             }

             has_dsss_param_set_chan_ = true;
             dsss_param_set_chan_ = ie->current_chan;
             debugbcn("%s Current channel: %u\n", dbgmsghdr, ie->current_chan);
             break;
         }
         case element_id::kCountry: {
             // TODO(porce): Handle Subband Triplet Sequence field.
             auto ie = reader.read<CountryElement>();
             if (ie == nullptr) {
                 debugbcn("%s Failed to parse\n", dbgmsghdr);
                 return ZX_ERR_INTERNAL;
             }

             char buf[CountryElement::kCountryLen + 1];
             snprintf(buf, sizeof(buf), "%s", ie->country);
             country_ = std::string(buf);
             debugbcn("%s Country: %s\n", dbgmsghdr, country_.c_str());
             break;
         }
         case element_id::kRsn: {
             auto ie = reader.read<RsnElement>();
             if (ie == nullptr) {
                 debugbcn("%s Failed to parse\n", dbgmsghdr);
                 return ZX_ERR_INTERNAL;
             }

             // TODO(porce): Consider pre-allocate max memory and recycle it.
             // if (rsne_) delete[] rsne_;
             size_t ie_len = sizeof(ElementHeader) + ie->hdr.len;
             rsne_.reset(new uint8_t[ie_len]);
             memcpy(rsne_.get(), ie, ie_len);
             rsne_len_ = ie_len;
             debugbcn("%s RSN\n", dbgmsghdr);
             break;
         }
         default:
             ie_unparsed_cnt++;
             debugbcn("%s Unparsed\n", dbgmsghdr);
             reader.skip(sizeof(ElementHeader) + hdr->len);
             break;
         }
     }

     debugbcn("  IE Summary: parsed %u / all %u\n", (ie_cnt - ie_unparsed_cnt), ie_cnt);
     return ZX_OK;
 }

 BeaconHash Bss::GetBeaconSignature(const Beacon& beacon, size_t frame_len) const {
     auto arr = reinterpret_cast<const uint8_t*>(&beacon);

     // Get a hash of the beacon except for its first field: timestamp.
     arr += sizeof(beacon.timestamp);
     frame_len -= sizeof(beacon.timestamp);

     BeaconHash hash = 0;
     // TODO(porce): Change to a less humble version.
     for (size_t idx = 0; idx < frame_len; idx++) {
         hash += *(arr + idx);
     }
     return hash;
 }

 fidl::StringPtr Bss::SsidToFidlString() {
     // TODO(porce): Merge into SSID Element upon IE revamp.
     return fidl::StringPtr(reinterpret_cast<const char*>(ssid_), ssid_len_);
 }

 wlan_mlme::BSSDescription Bss::ToFidl() {
     // Translates the Bss object into FIDL message.
     // Note, this API does not directly handle Beacon frame or ProbeResponse frame.

     wlan_mlme::BSSDescription fidl;

     std::memcpy(fidl.bssid.mutable_data(), bssid_.byte, common::kMacAddrLen);

     fidl.bss_type = GetBssType();
     fidl.ssid = SsidToFidlString();

     fidl.beacon_period = bcn_interval_;  // TODO(porce): consistent naming.
     fidl.timestamp = timestamp_;

     if (has_dsss_param_set_chan_ == true) {
         // Channel was explicitly announced by the AP
         fidl.chan.primary = dsss_param_set_chan_;
     } else {
         // Fallback to the inference
         fidl.chan.primary = bcn_rx_chan_.primary;
     }
     fidl.chan.cbw = static_cast<wlan_mlme::CBW>(bcn_rx_chan_.cbw);

     // Stats
     fidl.rssi_dbm = rssi_dbm_.val;
     fidl.rcpi_dbmh = rcpi_dbmh_.val;
     fidl.rsni_dbh = rsni_dbh_.val;

     // RSN
     fidl.rsn.reset();
     if (rsne_len_ > 0) {
         fidl.rsn = fidl::VectorPtr<uint8_t>::New(rsne_len_);
         memcpy(fidl.rsn->data(), rsne_.get(), rsne_len_);
     }

     return fidl;
 }

 std::string Bss::SsidToString() const {
     // SSID is of UTF-8 codepoints that may include NULL character.
     // Convert that to human-readable form in best effort.

     // TODO(porce): Implement this half-baked PoC code.

     bool is_printable = true;  // printable ascii
     for (size_t idx = 0; idx < ssid_len_; idx++) {
         if (ssid_[idx] < 32 || ssid_[idx] > 127) {
             is_printable = false;
             break;
         }
     }

     if (is_printable) {
         char buf[SsidElement::kMaxLen + 1];
         memcpy(buf, ssid_, ssid_len_);
         buf[ssid_len_] = '\0';  // NULL termination.
         return std::string(buf);
     }

     // Good luck
     char utf_buf[SsidElement::kMaxLen * 3];
     char* ptr = utf_buf;
     ptr += std::snprintf(ptr, 10, "[utf8] ");
     for (size_t idx = 0; idx < ssid_len_; idx++) {
         ptr += std::snprintf(ptr, 4, "%02x ", ssid_[idx]);
     }
     return std::string(utf_buf);
 }

 std::string Bss::SupportedRatesToString() const {
     // TODO(porce): Distinguish BSSBasicRateSet, OperationalRateSet, BSSMembershipSelectorSet.
     return "NOT_IMPLEMENTED";
 }

 }  // namespace wlan
	// Copyright 2017 The Fuchsia 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 <wlan/mlme/client/bss.h>

	#include <wlan/common/channel.h>

	#include <string>

	namespace wlan {

	namespace wlan_mlme = ::fuchsia::wlan::mlme;

	// TODO(NET-500): This file needs some clean-up.

	zx_status_t Bss::ProcessBeacon(const Beacon& beacon, size_t frame_len,
	const wlan_rx_info_t* rx_info) {
	if (!IsBeaconValid(beacon)) { return ZX_ERR_INTERNAL; }

	Renew(beacon, rx_info);

	if (!HasBeaconChanged(beacon, frame_len)) {
	// If unchanged, it is sufficient to renew the BSS. Bail out.
	return ZX_OK;
	}

	if (bcn_len_ != 0) {
	// TODO(porce): Identify varying IE, and do IE-by-IE comparison.
	// BSS had been discovered, but the beacon changed.
	// Suspicious situation. Consider Deauth if in assoc.
	debugbcn("BSSID %s beacon change detected. (len %zu -> %zu)\n", bssid_.ToString().c_str(),
	bcn_len_, frame_len);
	}

	auto status = Update(beacon, frame_len);
	if (status != ZX_OK) {
	debugbcn("BSSID %s failed to update its BSS object: (%d)\n", bssid_.ToString().c_str(),
	status);

	return status;
	}

	return ZX_OK;
	}

	std::string Bss::ToString() const {
	// TODO(porce): Convert to finspect Describe()
	char buf[1024];
	snprintf(
	buf, sizeof(buf), "BSSID %s Infra %s RSSI %3d Country %3s Channel %4s Cap %04x SSID [%s]",
	bssid_.ToString().c_str(), GetBssType() == wlan_mlme::BSSTypes::INFRASTRUCTURE ? "Y" : "N",
	rssi_dbm_.val, country_.c_str(), common::ChanStr(bcn_rx_chan_).c_str(), cap_.val(),
	SsidToString().c_str());
	return std::string(buf);
	}

	bool Bss::IsBeaconValid(const Beacon& beacon) const {
	// TODO(porce): Place holder. Add sanity logics.

	if (timestamp_ > beacon.timestamp) {
	// Suspicious. Wrap around?
	// TODO(porce): deauth if the client was in association.
	}

	// TODO(porce): Size check.
	// Note: Some beacons in 5GHz may not include DSSS Parameter Set IE

	return true;
	}

	void Bss::Renew(const Beacon& beacon, const wlan_rx_info_t* rx_info) {
	timestamp_ = beacon.timestamp;

	// TODO(porce): Take a deep look. Which resolution do we want to track?
	ts_refreshed_ = zx::clock::get(ZX_CLOCK_UTC);

	// Radio statistics.
	if (rx_info == nullptr) return;

	bcn_rx_chan_ = rx_info->chan;

	// If the latest beacons lack measurements, keep the last report.
	// TODO(NET-856): Change DDK wlan_rx_info_t and do translation in the vendor device driver.
	if (rx_info->valid_fields & WLAN_RX_INFO_VALID_RSSI) { rssi_dbm_.val = rx_info->rssi_dbm; }
	if (rx_info->valid_fields & WLAN_RX_INFO_VALID_RCPI) { rcpi_dbmh_.val = rx_info->rcpi_dbmh; }
	if (rx_info->valid_fields & WLAN_RX_INFO_VALID_SNR) { rsni_dbh_.val = rx_info->snr_dbh; }
	}

	bool Bss::HasBeaconChanged(const Beacon& beacon, size_t frame_len) const {
	// Test changes in beacon, except for the timestamp field.
	if (frame_len != bcn_len_) { return true; }
	auto sig = GetBeaconSignature(beacon, frame_len);
	if (sig != bcn_hash_) { return true; }
	return false;
	}

	zx_status_t Bss::Update(const Beacon& beacon, size_t frame_len) {
	// To be used to detect a change in Beacon.
	bcn_len_ = frame_len;
	bcn_hash_ = GetBeaconSignature(beacon, frame_len);

	// Fields that are always present.
	bcn_interval_ = beacon.beacon_interval;
	cap_ = beacon.cap;

	// IE's.
	auto ie_chains = beacon.elements;
	auto ie_chains_len = frame_len - sizeof(Beacon); // Subtract the beacon header len.

	ZX_DEBUG_ASSERT(ie_chains != nullptr);
	ZX_DEBUG_ASSERT(ie_chains_len <= frame_len);
	return ParseIE(ie_chains, ie_chains_len);
	}

	zx_status_t Bss::ParseIE(const uint8_t* ie_chains, size_t ie_chains_len) {
	ElementReader reader(ie_chains, ie_chains_len);

	debugbcn("Parsing IEs for BSSID %s\n", bssid_.ToString().c_str());
	uint8_t ie_cnt = 0;
	uint8_t ie_unparsed_cnt = 0;

	has_dsss_param_set_chan_ = false;

	char dbgmsghdr[128];
	while (reader.is_valid()) {
	ie_cnt++;

	const ElementHeader* hdr = reader.peek();
	if (hdr == nullptr) break;

	// TODO(porce): Process HT Capabilities IE's HT Capabilites Info to get CBW announcement.

	snprintf(dbgmsghdr, sizeof(dbgmsghdr), " IE %3u (Len %3u): ", hdr->id, hdr->len);
	switch (hdr->id) {
	case element_id::kSsid: {
	auto ie = reader.read<SsidElement>();
	if (ie == nullptr) {
	debugbcn("%s Failed to parse\n", dbgmsghdr);
	return ZX_ERR_INTERNAL;
	}

	ssid_len_ = ie->hdr.len;
	memcpy(ssid_, ie->ssid, ssid_len_);

	debugbcn("%s SSID: [%s]\n", dbgmsghdr, SsidToString().c_str());
	break;
	}
	case element_id::kSuppRates: {
	auto ie = reader.read<SupportedRatesElement>();
	if (ie == nullptr) {
	debugbcn("%s Failed to parse\n", dbgmsghdr);
	return ZX_ERR_INTERNAL;
	}

	for (uint8_t idx = 0; idx < ie->hdr.len; idx++) {
	supported_rates_.push_back(ie->rates[idx]);
	}
	debugbcn("%s Supported rates: %s\n", dbgmsghdr, SupportedRatesToString().c_str());
	break;
	}
	case element_id::kDsssParamSet: {
	auto ie = reader.read<DsssParamSetElement>();
	if (ie == nullptr) {
	debugbcn("%s Failed to parse\n", dbgmsghdr);
	return ZX_ERR_INTERNAL;
	}

	has_dsss_param_set_chan_ = true;
	dsss_param_set_chan_ = ie->current_chan;
	debugbcn("%s Current channel: %u\n", dbgmsghdr, ie->current_chan);
	break;
	}
	case element_id::kCountry: {
	// TODO(porce): Handle Subband Triplet Sequence field.
	auto ie = reader.read<CountryElement>();
	if (ie == nullptr) {
	debugbcn("%s Failed to parse\n", dbgmsghdr);
	return ZX_ERR_INTERNAL;
	}

	char buf[CountryElement::kCountryLen + 1];
	snprintf(buf, sizeof(buf), "%s", ie->country);
	country_ = std::string(buf);
	debugbcn("%s Country: %s\n", dbgmsghdr, country_.c_str());
	break;
	}
	case element_id::kRsn: {
	auto ie = reader.read<RsnElement>();
	if (ie == nullptr) {
	debugbcn("%s Failed to parse\n", dbgmsghdr);
	return ZX_ERR_INTERNAL;
	}

	// TODO(porce): Consider pre-allocate max memory and recycle it.
	// if (rsne_) delete[] rsne_;
	size_t ie_len = sizeof(ElementHeader) + ie->hdr.len;
	rsne_.reset(new uint8_t[ie_len]);
	memcpy(rsne_.get(), ie, ie_len);
	rsne_len_ = ie_len;
	debugbcn("%s RSN\n", dbgmsghdr);
	break;
	}
	default:
	ie_unparsed_cnt++;
	debugbcn("%s Unparsed\n", dbgmsghdr);
	reader.skip(sizeof(ElementHeader) + hdr->len);
	break;
	}
	}

	debugbcn(" IE Summary: parsed %u / all %u\n", (ie_cnt - ie_unparsed_cnt), ie_cnt);
	return ZX_OK;
	}

	BeaconHash Bss::GetBeaconSignature(const Beacon& beacon, size_t frame_len) const {
	auto arr = reinterpret_cast<const uint8_t*>(&beacon);

	// Get a hash of the beacon except for its first field: timestamp.
	arr += sizeof(beacon.timestamp);
	frame_len -= sizeof(beacon.timestamp);

	BeaconHash hash = 0;
	// TODO(porce): Change to a less humble version.
	for (size_t idx = 0; idx < frame_len; idx++) {
	hash += *(arr + idx);
	}
	return hash;
	}

	fidl::StringPtr Bss::SsidToFidlString() {
	// TODO(porce): Merge into SSID Element upon IE revamp.
	return fidl::StringPtr(reinterpret_cast<const char*>(ssid_), ssid_len_);
	}

	wlan_mlme::BSSDescription Bss::ToFidl() {
	// Translates the Bss object into FIDL message.
	// Note, this API does not directly handle Beacon frame or ProbeResponse frame.

	wlan_mlme::BSSDescription fidl;

	std::memcpy(fidl.bssid.mutable_data(), bssid_.byte, common::kMacAddrLen);

	fidl.bss_type = GetBssType();
	fidl.ssid = SsidToFidlString();

	fidl.beacon_period = bcn_interval_; // TODO(porce): consistent naming.
	fidl.timestamp = timestamp_;

	if (has_dsss_param_set_chan_ == true) {
	// Channel was explicitly announced by the AP
	fidl.chan.primary = dsss_param_set_chan_;
	} else {
	// Fallback to the inference
	fidl.chan.primary = bcn_rx_chan_.primary;
	}
	fidl.chan.cbw = static_cast<wlan_mlme::CBW>(bcn_rx_chan_.cbw);

	// Stats
	fidl.rssi_dbm = rssi_dbm_.val;
	fidl.rcpi_dbmh = rcpi_dbmh_.val;
	fidl.rsni_dbh = rsni_dbh_.val;

	// RSN
	fidl.rsn.reset();
	if (rsne_len_ > 0) {
	fidl.rsn = fidl::VectorPtr<uint8_t>::New(rsne_len_);
	memcpy(fidl.rsn->data(), rsne_.get(), rsne_len_);
	}

	return fidl;
	}

	std::string Bss::SsidToString() const {
	// SSID is of UTF-8 codepoints that may include NULL character.
	// Convert that to human-readable form in best effort.

	// TODO(porce): Implement this half-baked PoC code.

	bool is_printable = true; // printable ascii
	for (size_t idx = 0; idx < ssid_len_; idx++) {
	if (ssid_[idx] < 32 \|\| ssid_[idx] > 127) {
	is_printable = false;
	break;
	}
	}

	if (is_printable) {
	char buf[SsidElement::kMaxLen + 1];
	memcpy(buf, ssid_, ssid_len_);
	buf[ssid_len_] = '\0'; // NULL termination.
	return std::string(buf);
	}

	// Good luck
	char utf_buf[SsidElement::kMaxLen * 3];
	char* ptr = utf_buf;
	ptr += std::snprintf(ptr, 10, "[utf8] ");
	for (size_t idx = 0; idx < ssid_len_; idx++) {
	ptr += std::snprintf(ptr, 4, "%02x ", ssid_[idx]);
	}
	return std::string(utf_buf);
	}

	std::string Bss::SupportedRatesToString() const {
	// TODO(porce): Distinguish BSSBasicRateSet, OperationalRateSet, BSSMembershipSelectorSet.
	return "NOT_IMPLEMENTED";
	}

	} // namespace wlan