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Code Issues Releases Wiki Activity

Refactored DNS records.

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This commit is contained in:
Matias Fontanini
2012-09-17 00:11:24 -03:00
parent fc0ccffe18
commit ef8344394c
6 changed files with 499 additions and 246 deletions
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101
include/dns.h
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@@ -30,6 +30,7 @@
#include <map>
#include "pdu.h"
#include "endianness.h"
#include "dns_record.h"
namespace Tins {
class IPv4Address;
@@ -152,11 +153,6 @@ namespace Tins {
*/
DNS();
/**
* \brief Destructor.
*/
~DNS();
/**
* \brief Constructor which creates a DNS object from a buffer
* and adds all identifiable PDUs found in the buffer as
@@ -167,16 +163,6 @@ namespace Tins {
*/
DNS(const uint8_t *buffer, uint32_t total_sz);
/**
* \brief Copy constructor.
*/
DNS(const DNS& rhs);
/**
* \brief Copy assignment operator.
*/
DNS& operator=(const DNS& rhs);
// Getters
/**
@@ -518,81 +504,12 @@ namespace Tins {
authority, additional;
} __attribute__((packed));
struct ResourceRecord {
struct Info {
uint16_t type, qclass;
uint32_t ttl;
} __attribute__((packed)) info;
std::vector<uint8_t> data;
ResourceRecord(const uint8_t *d = 0, uint16_t len = 0) {
if(d && len)
data.assign(d, d + len);
}
virtual ~ResourceRecord() {}
virtual ResourceRecord *clone() const = 0;
uint32_t write(uint8_t *buffer) const;
virtual uint32_t do_write(uint8_t *buffer) const = 0;
virtual uint32_t size() const = 0;
virtual bool matches(const std::string &dname) { return false; }
uint32_t data_size() const {
return data.size();
}
const uint8_t *data_pointer() const {
return &data[0];
}
virtual const std::string *dname_pointer() const { return 0; }
};
struct OffsetedResourceRecord : public ResourceRecord {
uint16_t offset;
OffsetedResourceRecord(uint16_t off, const uint8_t *data = 0, uint16_t len = 0)
: ResourceRecord(data,len), offset(off | 0xc0) {}
uint32_t do_write(uint8_t *buffer) const {
std::memcpy(buffer, &offset, sizeof(offset));
return sizeof(offset);
}
uint32_t size() const {
return sizeof(ResourceRecord::info) + sizeof(offset) + data.size() + sizeof(uint16_t);
}
ResourceRecord *clone() const;
};
struct NamedResourceRecord : public ResourceRecord {
std::string name;
NamedResourceRecord(const std::string &nm, const uint8_t *data = 0, uint16_t len = 0)
: ResourceRecord(data,len), name(nm) {}
uint32_t do_write(uint8_t *buffer) const {
std::memcpy(buffer, name.c_str(), name.size() + 1);
return name.size() + 1;
}
uint32_t size() const {
return sizeof(ResourceRecord::info) + name.size() + 1 + data.size() + sizeof(uint16_t);
}
bool matches(const std::string &dname) {
return dname == name;
}
const std::string *dname_pointer() const {
return &name;
}
ResourceRecord *clone() const;
};
typedef std::map<uint16_t, std::string> SuffixMap;
typedef std::map<uint16_t, uint16_t> SuffixIndices;
typedef std::list<ResourceRecord*> ResourcesType;
typedef std::list<DNSResourceRecord> ResourcesType;
typedef std::list<Query> QueriesType;
const uint8_t *build_resource_list(std::list<ResourceRecord*> &lst, const uint8_t *ptr, uint32_t &sz, uint16_t nrecs);
const uint8_t *build_resource_list(ResourcesType &lst, const uint8_t *ptr, uint32_t &sz, uint16_t nrecs);
uint32_t find_domain_name(const std::string &dname);
bool find_domain_name(const std::string &dname, const ResourcesType &lst, uint16_t &out);
void parse_domain_name(const std::string &dn, std::string &out) const;
@@ -601,23 +518,19 @@ namespace Tins {
uint8_t *serialize_list(const ResourcesType &lst, uint8_t *buffer) const;
void compose_name(const uint8_t *ptr, uint32_t sz, std::string &out);
void convert_resources(const ResourcesType &lst, std::list<Resource> &res);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const std::string &dname);
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const uint8_t *ptr, uint32_t len);
DNSResourceRecord make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip);
DNSResourceRecord make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const std::string &dname);
DNSResourceRecord make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, const uint8_t *ptr, uint32_t len);
void add_suffix(uint32_t index, const uint8_t *data, uint32_t sz);
uint32_t build_suffix_map(uint32_t index, const ResourcesType &lst);
uint32_t build_suffix_map(uint32_t index, const QueriesType &lst);
void build_suffix_map();
void copy_list(const ResourcesType &from, ResourcesType &to) const;
bool contains_dname(uint16_t type);
void free_list(ResourcesType &lst);
void copy_fields(const DNS *other);
dnshdr dns;
uint32_t extra_size;
std::list<Query> queries;
std::list<ResourceRecord*> ans, arity, addit;
ResourcesType ans, arity, addit;
SuffixMap suffixes;
SuffixIndices suffix_indices;
};

231
include/dns_record.h Normal file
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@@ -0,0 +1,231 @@
/*
* libtins is a net packet wrapper library for crafting and
* interpreting sniffed packets.
*
* Copyright (C) 2011 Nasel
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef TINS_DNS_RECORD_H
#define TINS_DNS_RECORD_H
#include <string>
#include <vector>
#include <stdint.h>
namespace Tins {
class DNSRRImpl;
/**
* \brief Abstracts a DNS resource record.
*/
class DNSResourceRecord {
public:
/**
* \brief The type used to store resource records' information.
*/
struct Info {
uint16_t type, qclass;
uint32_t ttl;
} __attribute__((packed));
/**
* \brief Constructs a record.
* \param impl A pointer to the impl object.
* \param data A pointer to the start of the data buffer.
* \param len The length of the data.
*/
DNSResourceRecord(DNSRRImpl *impl = 0, const uint8_t *data = 0, uint16_t len = 0);
/**
* \brief Constructs a record.
* \param buffer A pointer to the start of the data buffer.
* \param len The length of the data.
*/
DNSResourceRecord(const uint8_t *buffer, uint32_t size);
/**
* \brief Constructs a record from an input range.
* \param impl A pointer to the impl object.
* \param start The begining of the range.
* \param end The end of the range.
*/
template<typename ForwardIterator>
DNSResourceRecord(DNSRRImpl *impl, ForwardIterator start, ForwardIterator end)
: impl(impl), data(start, end)
{ }
/**
* \brief Copy constructor.
*
* This handles cloning the impl object.
* \param rhs The record which will be copied.
*/
DNSResourceRecord(const DNSResourceRecord &rhs);
/**
* \brief Copy assignment operator.
*
* This handles cloning the impl object.
* \param rhs The record which will be copied.
*/
DNSResourceRecord& operator=(const DNSResourceRecord &rhs);
/**
* \brief Destructor.
*
* This frees the impl object.
*/
~DNSResourceRecord();
/**
* \brief Writes this record to a buffer.
*
* \param buffer The buffer in which to store the serialization.
* \return uint32_t containing the number of bytes written.
*/
uint32_t write(uint8_t *buffer) const;
/**
* \brief Returns the size of the data in this record.
*/
uint32_t data_size() const {
return data.size();
}
/**
* \brief Returns the pointer to the start of the data buffer.
*/
const uint8_t *data_ptr() const {
return &data[0];
}
/**
* \brief Returns a bool indicating whether this record contains
* a domain name as the name being resolved.
*/
bool has_domain_name() const;
/**
* \brief Returns a pointer to the domain name stored in this record.
*
* This will throw a std::bad_cast exception if the impl object is
* not of the type NamedDNSRRImpl.
*/
const std::string *dname() const;
/**
* \brief Returns the offset stored in this record.
*
* This will throw a std::bad_cast exception if the impl object is
* not of the type OffsetedDNSRRImpl.
*/
uint16_t offset() const;
/**
* \brief Returns the size of this record.
*/
uint32_t size() const;
/**
* \brief Returns a reference to the info field.
*/
Info &info() {
return info_;
}
/**
* \brief Returns a const reference to the info field.
*/
const Info &info() const {
return info_;
}
/**
* \brief Checks if the domain name stored in this record matches
* the given one.
*
* This is a shortcut
*/
bool matches(const std::string &dname) const;
private:
DNSRRImpl *clone_impl() const;
size_t impl_size() const;
Info info_;
std::vector<uint8_t> data;
DNSRRImpl *impl;
};
/**
* \cond
*/
class DNSRRImpl {
public:
virtual ~DNSRRImpl() {}
virtual uint32_t size() const = 0;
virtual uint32_t do_write(uint8_t *buffer) const = 0;
virtual bool matches(const std::string &dname) const { return false; }
virtual DNSRRImpl *clone() const = 0;
};
class OffsetedDNSRRImpl : public DNSRRImpl {
public:
OffsetedDNSRRImpl(uint16_t off);
uint32_t do_write(uint8_t *buffer) const;
uint32_t size() const;
OffsetedDNSRRImpl *clone() const;
uint16_t offset() const;
private:
uint16_t offset_;
};
class NamedDNSRRImpl : public DNSRRImpl {
public:
NamedDNSRRImpl(const std::string &nm);
template<typename ForwardIterator>
NamedDNSRRImpl(ForwardIterator start, ForwardIterator end)
: name(start, end)
{ }
uint32_t do_write(uint8_t *buffer) const;
uint32_t size() const;
bool matches(const std::string &dname) const;
const std::string *dname_pointer() const;
NamedDNSRRImpl *clone() const;
private:
std::string name;
};
/**
* \endcond
*/
inline DNSResourceRecord make_offseted_record(uint16_t offset, const uint8_t *data = 0, uint32_t size = 0) {
return DNSResourceRecord(new OffsetedDNSRRImpl(offset), data, size);
}
inline DNSResourceRecord make_named_record(const std::string &name, const uint8_t *data = 0, uint32_t size = 0) {
return DNSResourceRecord(new NamedDNSRRImpl(name), data, size);
}
}
#endif // TINS_DNS_RECORD_H