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/*
* Copyright (c) 2017-2021 Cisco and/or its affiliates.
* 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:
*
* http://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 <core/facade.h>
#include <protocols/rtc/rtc_packet.h>
#include <protocols/rtc/rtc_verifier.h>
namespace transport {
namespace protocol {
namespace rtc {
RTCVerifier::RTCVerifier(std::shared_ptr<auth::Verifier> verifier,
uint32_t max_unverified_delay)
: verifier_(verifier), max_unverified_delay_(max_unverified_delay) {}
void RTCVerifier::setState(std::shared_ptr<RTCState> rtc_state) {
rtc_state_ = rtc_state;
}
void RTCVerifier::setVerifier(std::shared_ptr<auth::Verifier> verifier) {
verifier_ = verifier;
}
void RTCVerifier::setMaxUnverifiedDelay(uint32_t max_unverified_delay) {
max_unverified_delay_ = max_unverified_delay;
}
auth::VerificationPolicy RTCVerifier::verify(
core::ContentObject &content_object, bool is_fec) {
uint32_t suffix = content_object.getName().getSuffix();
core::PayloadType payload_type = content_object.getPayloadType();
bool is_probe = ProbeHandler::getProbeType(suffix) != ProbeType::NOT_PROBE;
bool is_nack = !is_probe && content_object.payloadSize() == NACK_HEADER_SIZE;
bool is_manifest = !is_probe && !is_nack && !is_fec &&
payload_type == core::PayloadType::MANIFEST;
bool is_data = !is_probe && !is_nack && !is_fec &&
payload_type == core::PayloadType::DATA;
if (is_probe) return verifyProbe(content_object);
if (is_nack) return verifyNack(content_object);
if (is_fec) return verifyFec(content_object);
if (is_data) return verifyData(content_object);
if (is_manifest) return verifyManifest(content_object);
auth::VerificationPolicy policy = auth::VerificationPolicy::ABORT;
verifier_->callVerificationFailedCallback(suffix, policy);
return policy;
}
auth::VerificationPolicy RTCVerifier::verifyProbe(
core::ContentObject &content_object) {
switch (ProbeHandler::getProbeType(content_object.getName().getSuffix())) {
case ProbeType::INIT: {
auth::VerificationPolicy policy = verifyManifest(content_object);
if (policy != auth::VerificationPolicy::ACCEPT) {
return policy;
}
return processManifest(content_object);
}
case ProbeType::RTT:
return verifyNack(content_object);
default:
auth::VerificationPolicy policy = auth::VerificationPolicy::ABORT;
verifier_->callVerificationFailedCallback(
content_object.getName().getSuffix(), policy);
return policy;
}
}
auth::VerificationPolicy RTCVerifier::verifyNack(
core::ContentObject &content_object) {
return verifier_->verifyPackets(&content_object);
}
auth::VerificationPolicy RTCVerifier::verifyFec(
core::ContentObject &content_object) {
return verifier_->verifyPackets(&content_object);
}
auth::VerificationPolicy RTCVerifier::verifyData(
core::ContentObject &content_object) {
uint32_t suffix = content_object.getName().getSuffix();
if (_is_ah(content_object.getFormat())) {
return verifier_->verifyPackets(&content_object);
}
unverified_bytes_[suffix] =
content_object.headerSize() + content_object.payloadSize();
unverified_packets_[suffix] =
content_object.computeDigest(manifest_hash_algo_);
// An alert is raised when too much packets remain unverified
if (getTotalUnverified() > max_unverified_bytes_) {
unverified_bytes_.clear();
unverified_packets_.clear();
auth::VerificationPolicy policy = auth::VerificationPolicy::ABORT;
verifier_->callVerificationFailedCallback(suffix, policy);
return policy;
}
return auth::VerificationPolicy::ACCEPT;
}
auth::VerificationPolicy RTCVerifier::verifyManifest(
core::ContentObject &content_object) {
return verifier_->verifyPackets(&content_object);
}
auth::VerificationPolicy RTCVerifier::processManifest(
core::ContentObject &content_object) {
uint32_t suffix = content_object.getName().getSuffix();
core::ContentObjectManifest manifest(content_object);
manifest.decode();
// Update last manifest
if (suffix > last_manifest_) {
last_manifest_ = suffix;
}
// Extract parameters
manifest_hash_algo_ = manifest.getHashAlgorithm();
core::ParamsRTC params = manifest.getParamsRTC();
if (params.prod_rate > 0) {
max_unverified_bytes_ = static_cast<uint64_t>(
(max_unverified_delay_ / 1000.0) * params.prod_rate);
}
if (max_unverified_bytes_ == 0 || !rtc_state_) {
auth::VerificationPolicy policy = auth::VerificationPolicy::ABORT;
verifier_->callVerificationFailedCallback(suffix, policy);
return policy;
}
// Extract hashes
auth::Verifier::SuffixMap suffix_map =
core::ContentObjectManifest::getSuffixMap(&manifest);
// Return early if the manifest is empty
if (suffix_map.empty()) {
return auth::VerificationPolicy::ACCEPT;
}
// Remove lost packets from digest map
manifest_digests_.insert(suffix_map.begin(), suffix_map.end());
for (auto it = manifest_digests_.begin(); it != manifest_digests_.end();) {
if (rtc_state_->getPacketState(it->first) == PacketState::DEFINITELY_LOST) {
unverified_packets_.erase(it->first);
unverified_bytes_.erase(it->first);
it = manifest_digests_.erase(it);
} else {
++it;
}
}
// Verify packets
auth::Verifier::PolicyMap policies =
verifier_->verifyHashes(unverified_packets_, manifest_digests_);
for (const auto &policy : policies) {
switch (policy.second) {
case auth::VerificationPolicy::ACCEPT: {
manifest_digests_.erase(policy.first);
unverified_packets_.erase(policy.first);
unverified_bytes_.erase(policy.first);
break;
}
case auth::VerificationPolicy::UNKNOWN:
break;
case auth::VerificationPolicy::DROP:
case auth::VerificationPolicy::ABORT:
auth::VerificationPolicy p = policy.second;
verifier_->callVerificationFailedCallback(policy.first, p);
return p;
}
}
return auth::VerificationPolicy::ACCEPT;
}
void RTCVerifier::onDataRecoveredFec(uint32_t suffix) {
manifest_digests_.erase(suffix);
}
void RTCVerifier::onJumpForward(uint32_t next_suffix) {
if (next_suffix <= last_manifest_ + 1) {
return;
}
// When we jump forward in the suffix sequence, we remove packets that
// probably won't be verified. Those packets have a suffix in the range
// [last_manifest_ + 1, next_suffix[.
for (auto it = unverified_packets_.begin();
it != unverified_packets_.end();) {
if (it->first > last_manifest_) {
unverified_bytes_.erase(it->first);
it = unverified_packets_.erase(it);
} else {
++it;
}
}
}
uint32_t RTCVerifier::getTotalUnverified() const {
uint32_t total = 0;
for (auto bytes : unverified_bytes_) {
if (bytes.second > UINT32_MAX - total) {
total = UINT32_MAX;
break;
}
total += bytes.second;
}
return total;
}
uint32_t RTCVerifier::getMaxUnverified() const { return max_unverified_bytes_; }
} // end namespace rtc
} // end namespace protocol
} // end namespace transport
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