1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91
|
// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_DNS_DNS_RESPONSE_RESULT_EXTRACTOR_H_
#define NET_DNS_DNS_RESPONSE_RESULT_EXTRACTOR_H_
#include <stdint.h>
#include <memory>
#include <set>
#include <string_view>
#include "base/memory/raw_ptr.h"
#include "base/time/clock.h"
#include "base/time/default_clock.h"
#include "base/time/default_tick_clock.h"
#include "base/types/expected.h"
#include "net/base/net_export.h"
#include "net/dns/host_cache.h"
#include "net/dns/public/dns_query_type.h"
namespace net {
class DnsResponse;
class HostResolverInternalResult;
// Higher-level parser to take a DnsResponse and extract results.
class NET_EXPORT_PRIVATE DnsResponseResultExtractor {
public:
enum class ExtractionError {
kOk = 0,
// Record failed to parse.
kMalformedRecord,
// Malformed CNAME
kMalformedCname,
// Found CNAME or result record with an unexpected name.
kNameMismatch,
// Malformed result record
kMalformedResult,
// CNAME record after a result record
kCnameAfterResult,
// Multiple CNAME records for the same owner name.
kMultipleCnames,
// Invalid alias chain, e.g. contains loops or disjoint aliases.
kBadAliasChain,
};
static constexpr std::string_view kHasValidCnameRecordsHistogram =
"Net.DNS.DnsTask.HasValidCnameRecords";
using ResultsOrError =
base::expected<std::set<std::unique_ptr<HostResolverInternalResult>>,
ExtractionError>;
// References must stay alive for the life of the created extractor.
explicit DnsResponseResultExtractor(
const DnsResponse& response,
const base::Clock& clock = *base::DefaultClock::GetInstance(),
const base::TickClock& tick_clock =
*base::DefaultTickClock::GetInstance());
~DnsResponseResultExtractor();
DnsResponseResultExtractor(const DnsResponseResultExtractor&) = delete;
DnsResponseResultExtractor& operator=(const DnsResponseResultExtractor&) =
delete;
// Extract results from the response. `query_type` must match the qtype from
// the DNS query, and it must have already been validated (expected to be done
// by DnsTransaction) that the response matches the query.
//
// `original_domain_name` is the query name (in dotted form) before any
// aliasing or prepending port/scheme. It is expected to be the name under
// which any basic query types, e.g. A or AAAA, are queried.
//
// May have the side effect of recording metrics about DnsResponses as they
// are parsed, so while not an absolute requirement, any given DnsResponse
// should only be used and extracted from at most once.
ResultsOrError ExtractDnsResults(DnsQueryType query_type,
std::string_view original_domain_name,
uint16_t request_port) const;
private:
const raw_ref<const DnsResponse> response_;
const raw_ref<const base::Clock> clock_;
const raw_ref<const base::TickClock> tick_clock_;
};
} // namespace net
#endif // NET_DNS_DNS_RESPONSE_RESULT_EXTRACTOR_H_
|