1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 18:47:34 +00:00

LookupServer: Introduce DNSName

This is a wrapper around a string representing a domain name (such as
"example.com"). It never has a trailing dot.

For now, this class doesn't do much except wrap the raw string. Subsequent
commits will add or move more functionality to it.
This commit is contained in:
Sergey Bugaev 2021-02-14 15:02:02 +03:00 committed by Andreas Kling
parent de811faf55
commit ae1e82fd2f
9 changed files with 117 additions and 38 deletions

View file

@ -3,6 +3,7 @@ compile_ipc(LookupClient.ipc LookupClientEndpoint.h)
set(SOURCES
DNSAnswer.cpp
DNSName.cpp
DNSPacket.cpp
LookupServer.cpp
LookupServerEndpoint.h

View file

@ -29,7 +29,7 @@
namespace LookupServer {
DNSAnswer::DNSAnswer(const String& name, u16 type, u16 class_code, u32 ttl, const String& record_data)
DNSAnswer::DNSAnswer(const DNSName& name, u16 type, u16 class_code, u32 ttl, const String& record_data)
: m_name(name)
, m_type(type)
, m_class_code(class_code)

View file

@ -26,6 +26,7 @@
#pragma once
#include "DNSName.h"
#include <AK/String.h>
#include <AK/Types.h>
@ -33,9 +34,9 @@ namespace LookupServer {
class DNSAnswer {
public:
DNSAnswer(const String& name, u16 type, u16 class_code, u32 ttl, const String& record_data);
DNSAnswer(const DNSName& name, u16 type, u16 class_code, u32 ttl, const String& record_data);
const String& name() const { return m_name; }
const DNSName& name() const { return m_name; }
u16 type() const { return m_type; }
u16 class_code() const { return m_class_code; }
u32 ttl() const { return m_ttl; }
@ -44,7 +45,7 @@ public:
bool has_expired() const;
private:
String m_name;
DNSName m_name;
u16 m_type { 0 };
u16 m_class_code { 0 };
u32 m_ttl { 0 };

View file

@ -0,0 +1,39 @@
/*
* Copyright (c) 2021, Sergey Bugaev <bugaevc@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "DNSName.h"
namespace LookupServer {
DNSName::DNSName(const String& name)
{
if (name.ends_with('.'))
m_name = name.substring(0, name.length() - 1);
else
m_name = name;
}
}

View file

@ -0,0 +1,42 @@
/*
* Copyright (c) 2021, Sergey Bugaev <bugaevc@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/String.h>
namespace LookupServer {
class DNSName {
public:
DNSName(const String&);
const String& as_string() const { return m_name; }
private:
String m_name;
};
}

View file

@ -58,9 +58,6 @@ void DNSPacket::add_question(const String& name, u16 record_type, ShouldRandomiz
builder.append(ch);
}
if (name[name.length() - 1] != '.')
builder.append('.');
m_questions.empend(builder.to_string(), record_type, (u16)C_IN);
}
@ -85,7 +82,7 @@ ByteBuffer DNSPacket::to_byte_buffer() const
stream << ReadonlyBytes { &header, sizeof(header) };
for (auto& question : m_questions) {
auto parts = question.name().split('.');
auto parts = question.name().as_string().split('.');
for (auto& part : parts) {
stream << (u8)part.length();
stream << part.bytes();
@ -95,7 +92,7 @@ ByteBuffer DNSPacket::to_byte_buffer() const
stream << htons(question.class_code());
}
for (auto& answer : m_answers) {
auto parts = answer.name().split('.');
auto parts = answer.name().as_string().split('.');
for (auto& part : parts) {
stream << (u8)part.length();
stream << part.bytes();

View file

@ -26,12 +26,14 @@
#pragma once
#include <AK/String.h>
#include "DNSName.h"
#include <AK/Types.h>
namespace LookupServer {
class DNSQuestion {
public:
DNSQuestion(const String& name, u16 record_type, u16 class_code)
DNSQuestion(const DNSName& name, u16 record_type, u16 class_code)
: m_name(name)
, m_record_type(record_type)
, m_class_code(class_code)
@ -40,20 +42,12 @@ public:
u16 record_type() const { return m_record_type; }
u16 class_code() const { return m_class_code; }
const String& name() const { return m_name; }
bool operator==(const DNSQuestion& other) const
{
return m_name == other.m_name && m_record_type == other.m_record_type && m_class_code == other.m_class_code;
}
bool operator!=(const DNSQuestion& other) const
{
return !(*this == other);
}
const DNSName& name() const { return m_name; }
private:
String m_name;
DNSName m_name;
u16 m_record_type { 0 };
u16 m_class_code { 0 };
};
}

View file

@ -113,17 +113,17 @@ void LookupServer::load_etc_hosts()
}
}
Vector<String> LookupServer::lookup(const String& name, unsigned short record_type)
Vector<String> LookupServer::lookup(const DNSName& name, unsigned short record_type)
{
#if LOOKUPSERVER_DEBUG
dbgln("Got request for '{}'", name);
dbgln("Got request for '{}'", name.as_string());
#endif
Vector<String> responses;
if (auto known_host = m_etc_hosts.get(name); known_host.has_value()) {
if (auto known_host = m_etc_hosts.get(name.as_string()); known_host.has_value()) {
responses.append(known_host.value());
} else if (!name.is_empty()) {
} else if (!name.as_string().is_empty()) {
for (auto& nameserver : m_nameservers) {
#if LOOKUPSERVER_DEBUG
dbgln("Doing lookup using nameserver '{}'", nameserver);
@ -153,15 +153,15 @@ Vector<String> LookupServer::lookup(const String& name, unsigned short record_ty
return move(responses);
}
Vector<String> LookupServer::lookup(const String& hostname, const String& nameserver, bool& did_get_response, unsigned short record_type, ShouldRandomizeCase should_randomize_case)
Vector<String> LookupServer::lookup(const DNSName& name, const String& nameserver, bool& did_get_response, unsigned short record_type, ShouldRandomizeCase should_randomize_case)
{
if (auto it = m_lookup_cache.find(hostname); it != m_lookup_cache.end()) {
if (auto it = m_lookup_cache.find(name.as_string()); it != m_lookup_cache.end()) {
auto& cached_lookup = it->value;
if (cached_lookup.question.record_type() == record_type) {
Vector<String> responses;
for (auto& cached_answer : cached_lookup.answers) {
#if LOOKUPSERVER_DEBUG
dbgln("Cache hit: {} -> {}, expired: {}", hostname, cached_answer.record_data(), cached_answer.has_expired());
dbgln("Cache hit: {} -> {}, expired: {}", name.as_string(), cached_answer.record_data(), cached_answer.has_expired());
#endif
if (!cached_answer.has_expired())
responses.append(cached_answer.record_data());
@ -175,7 +175,7 @@ Vector<String> LookupServer::lookup(const String& hostname, const String& namese
DNSPacket request;
request.set_is_query();
request.set_id(arc4random_uniform(UINT16_MAX));
request.add_question(hostname, record_type, should_randomize_case);
request.add_question(name.as_string(), record_type, should_randomize_case);
auto buffer = request.to_byte_buffer();
@ -219,7 +219,7 @@ Vector<String> LookupServer::lookup(const String& hostname, const String& namese
if (response.code() == DNSPacket::Code::REFUSED) {
if (should_randomize_case == ShouldRandomizeCase::Yes) {
// Retry with 0x20 case randomization turned off.
return lookup(hostname, nameserver, did_get_response, record_type, ShouldRandomizeCase::No);
return lookup(name, nameserver, did_get_response, record_type, ShouldRandomizeCase::No);
}
return {};
}
@ -229,13 +229,17 @@ Vector<String> LookupServer::lookup(const String& hostname, const String& namese
return {};
}
// Verify the questions in our request and in their response match exactly, including case.
for (size_t i = 0; i < request.question_count(); ++i) {
auto& request_question = request.questions()[i];
auto& response_question = response.questions()[i];
if (request_question != response_question) {
bool exact_match = request_question.class_code() == response_question.class_code()
&& request_question.record_type() == response_question.record_type()
&& request_question.name().as_string() == response_question.name().as_string();
if (!exact_match) {
dbgln("Request and response questions do not match");
dbgln(" Request: name=_{}_, type={}, class={}", request_question.name(), response_question.record_type(), response_question.class_code());
dbgln(" Response: name=_{}_, type={}, class={}", response_question.name(), response_question.record_type(), response_question.class_code());
dbgln(" Request: name=_{}_, type={}, class={}", request_question.name().as_string(), response_question.record_type(), response_question.class_code());
dbgln(" Response: name=_{}_, type={}, class={}", response_question.name().as_string(), response_question.record_type(), response_question.class_code());
return {};
}
}
@ -258,7 +262,7 @@ Vector<String> LookupServer::lookup(const String& hostname, const String& namese
if (!cacheable_answers.is_empty()) {
if (m_lookup_cache.size() >= 256)
m_lookup_cache.remove(m_lookup_cache.begin());
m_lookup_cache.set(hostname, { request.questions()[0], move(cacheable_answers) });
m_lookup_cache.set(name.as_string(), { request.questions()[0], move(cacheable_answers) });
}
return responses;
}

View file

@ -27,6 +27,7 @@
#pragma once
#include "DNSPacket.h"
#include "DNSName.h"
#include <LibCore/Object.h>
namespace LookupServer {
@ -38,13 +39,13 @@ class LookupServer final : public Core::Object {
public:
static LookupServer& the();
Vector<String> lookup(const String& name, unsigned short record_type);
Vector<String> lookup(const DNSName& name, unsigned short record_type);
private:
LookupServer();
void load_etc_hosts();
Vector<String> lookup(const String& hostname, const String& nameserver, bool& did_get_response, unsigned short record_type, ShouldRandomizeCase = ShouldRandomizeCase::Yes);
Vector<String> lookup(const DNSName& hostname, const String& nameserver, bool& did_get_response, unsigned short record_type, ShouldRandomizeCase = ShouldRandomizeCase::Yes);
struct CachedLookup {
DNSQuestion question;