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// Copyright 2019 The Chromium 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 "discovery/dnssd/impl/conversion_layer.h"
#include <utility>
#include "absl/strings/str_join.h"
#include "absl/strings/str_split.h"
#include "absl/types/optional.h"
#include "absl/types/span.h"
#include "discovery/dnssd/impl/constants.h"
#include "discovery/dnssd/impl/instance_key.h"
#include "discovery/dnssd/impl/service_key.h"
#include "discovery/dnssd/public/dns_sd_instance.h"
#include "discovery/mdns/mdns_records.h"
#include "discovery/mdns/public/mdns_constants.h"
namespace openscreen {
namespace discovery {
namespace {
void AddServiceInfoToLabels(const std::string& service,
const std::string& domain,
std::vector<std::string>* labels) {
std::vector<std::string> service_labels = absl::StrSplit(service, '.');
labels->insert(labels->end(), service_labels.begin(), service_labels.end());
std::vector<std::string> domain_labels = absl::StrSplit(domain, '.');
labels->insert(labels->end(), domain_labels.begin(), domain_labels.end());
}
DomainName GetPtrDomainName(const std::string& service,
const std::string& domain) {
std::vector<std::string> labels;
AddServiceInfoToLabels(service, domain, &labels);
return DomainName{std::move(labels)};
}
DomainName GetInstanceDomainName(const std::string& instance,
const std::string& service,
const std::string& domain) {
std::vector<std::string> labels;
labels.emplace_back(instance);
AddServiceInfoToLabels(service, domain, &labels);
return DomainName{std::move(labels)};
}
inline DomainName GetInstanceDomainName(const InstanceKey& key) {
return GetInstanceDomainName(key.instance_id(), key.service_id(),
key.domain_id());
}
MdnsRecord CreatePtrRecord(const DnsSdInstance& instance,
const DomainName& domain) {
PtrRecordRdata data(domain);
auto outer_domain =
GetPtrDomainName(instance.service_id(), instance.domain_id());
return MdnsRecord(std::move(outer_domain), DnsType::kPTR, DnsClass::kIN,
RecordType::kShared, kPtrRecordTtl, std::move(data));
}
MdnsRecord CreateSrvRecord(const DnsSdInstance& instance,
const DomainName& domain) {
uint16_t port = instance.port();
SrvRecordRdata data(0, 0, port, domain);
return MdnsRecord(domain, DnsType::kSRV, DnsClass::kIN, RecordType::kUnique,
kSrvRecordTtl, std::move(data));
}
std::vector<MdnsRecord> CreateARecords(const DnsSdInstanceEndpoint& endpoint,
const DomainName& domain) {
std::vector<MdnsRecord> records;
for (const IPAddress& address : endpoint.addresses()) {
if (address.IsV4()) {
ARecordRdata data(address);
records.emplace_back(domain, DnsType::kA, DnsClass::kIN,
RecordType::kUnique, kARecordTtl, std::move(data));
}
}
return records;
}
std::vector<MdnsRecord> CreateAAAARecords(const DnsSdInstanceEndpoint& endpoint,
const DomainName& domain) {
std::vector<MdnsRecord> records;
for (const IPAddress& address : endpoint.addresses()) {
if (address.IsV6()) {
AAAARecordRdata data(address);
records.emplace_back(domain, DnsType::kAAAA, DnsClass::kIN,
RecordType::kUnique, kAAAARecordTtl,
std::move(data));
}
}
return records;
}
MdnsRecord CreateTxtRecord(const DnsSdInstance& endpoint,
const DomainName& domain) {
TxtRecordRdata data(endpoint.txt().GetData());
return MdnsRecord(domain, DnsType::kTXT, DnsClass::kIN, RecordType::kUnique,
kTXTRecordTtl, std::move(data));
}
} // namespace
ErrorOr<DnsSdTxtRecord> CreateFromDnsTxt(const TxtRecordRdata& txt_data) {
DnsSdTxtRecord txt;
if (txt_data.texts().size() == 1 && txt_data.texts()[0] == "") {
return txt;
}
// Iterate backwards so that the first key of each type is the one that is
// present at the end, as pet spec.
for (auto it = txt_data.texts().rbegin(); it != txt_data.texts().rend();
it++) {
const std::string& text = *it;
size_t index_of_eq = text.find_first_of('=');
if (index_of_eq != std::string::npos) {
if (index_of_eq == 0) {
return Error::Code::kParameterInvalid;
}
std::string key = text.substr(0, index_of_eq);
std::string value = text.substr(index_of_eq + 1);
absl::Span<const uint8_t> data(
reinterpret_cast<const uint8_t*>(value.data()), value.size());
const auto set_result =
txt.SetValue(key, std::vector<uint8_t>(data.begin(), data.end()));
if (!set_result.ok()) {
return set_result;
}
} else {
const auto set_result = txt.SetFlag(text, true);
if (!set_result.ok()) {
return set_result;
}
}
}
return txt;
}
DomainName GetDomainName(const InstanceKey& key) {
return GetInstanceDomainName(key.instance_id(), key.service_id(),
key.domain_id());
}
DomainName GetDomainName(const MdnsRecord& record) {
return IsPtrRecord(record)
? absl::get<PtrRecordRdata>(record.rdata()).ptr_domain()
: record.name();
}
DnsQueryInfo GetInstanceQueryInfo(const InstanceKey& key) {
return {GetDomainName(key), DnsType::kANY, DnsClass::kANY};
}
DnsQueryInfo GetPtrQueryInfo(const ServiceKey& key) {
auto domain = GetPtrDomainName(key.service_id(), key.domain_id());
return {std::move(domain), DnsType::kPTR, DnsClass::kANY};
}
bool HasValidDnsRecordAddress(const MdnsRecord& record) {
return HasValidDnsRecordAddress(GetDomainName(record));
}
bool HasValidDnsRecordAddress(const DomainName& domain) {
return InstanceKey::TryCreate(domain).is_value() &&
IsInstanceValid(domain.labels()[0]);
}
bool IsPtrRecord(const MdnsRecord& record) {
return record.dns_type() == DnsType::kPTR;
}
std::vector<MdnsRecord> GetDnsRecords(const DnsSdInstance& instance) {
auto domain = GetInstanceDomainName(InstanceKey(instance));
return {CreatePtrRecord(instance, domain), CreateSrvRecord(instance, domain),
CreateTxtRecord(instance, domain)};
}
std::vector<MdnsRecord> GetDnsRecords(const DnsSdInstanceEndpoint& endpoint) {
auto domain = GetInstanceDomainName(InstanceKey(endpoint));
std::vector<MdnsRecord> records =
GetDnsRecords(static_cast<DnsSdInstance>(endpoint));
std::vector<MdnsRecord> v4 = CreateARecords(endpoint, domain);
std::vector<MdnsRecord> v6 = CreateAAAARecords(endpoint, domain);
records.insert(records.end(), v4.begin(), v4.end());
records.insert(records.end(), v6.begin(), v6.end());
return records;
}
} // namespace discovery
} // namespace openscreen
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