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Code Issues Releases Wiki Activity

DNS is working. Constructor from buffer is not implemented yet.

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This commit is contained in:
Matias Fontanini
2012-03-30 01:03:36 -03:00
parent e81d9b7ea7
commit b55bafaedd
3 changed files with 467 additions and 10 deletions
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320
include/dns.h
View File

@@ -23,6 +23,8 @@
#define __DNS_H
#include <stdint.h>
#include <list>
#include <string>
#include "pdu.h"
namespace Tins {
@@ -33,6 +35,209 @@ namespace Tins {
RESPONSE = 1
};
/**
* \brief Query types enum.
*/
enum QueryType {
A = 1,
NS,
MD,
MF,
CNAME,
SOA,
MB,
MG,
MR,
NULL_R,
WKS,
PTR,
HINFO,
MINFO,
MX,
TXT,
RP,
AFSDB,
X25,
ISDN,
RT,
NSAP,
NSAP_PTR,
SIG,
KEY,
PX,
GPOS,
AAAA,
LOC,
NXT,
EID,
NIMLOC,
SRV,
ATMA,
NAPTR,
KX,
CERT,
A6,
DNAM,
SINK,
OPT,
APL,
DS,
SSHFP,
IPSECKEY,
RRSIG,
NSEC,
DNSKEY,
DHCID,
NSEC3,
NSEC3PARAM
};
enum QueryClass {
IN = 1,
CH = 3,
HS = 4,
ANY = 255
};
/**
* \brief Default constructor.
*
* This constructor initializes every field to 0.
*/
DNS();
/**
* \brief Destructor.
*/
~DNS();
// Getters
/**
* \brief Setter for the id field.
*
* \return uint16_t containing the value of the id field.
*/
uint16_t id() { return dns.id; }
/**
* \brief Setter for the query response field.
*
* \return QRType containing the value of the query response
* field.
*/
QRType type() { return static_cast<QRType>(dns.qr); }
/**
* \brief Setter for the opcode field.
*
* \return uint8_t containing the value of the opcode field.
*/
uint8_t opcode() { return dns.opcode; }
/**
* \brief Setter for the authoritative answer field.
*
* \return uint8_t containing the value of the authoritative
* answer field.
*/
uint8_t authoritative_answer() { return dns.aa; }
/**
* \brief Setter for the truncated field.
*
* \return uint8_t containing the value of the truncated field.
*/
uint8_t truncated() { return dns.tc; }
/**
* \brief Setter for the recursion desired field.
*
* \return uint8_t containing the value of the recursion
* desired field.
*/
uint8_t recursion_desired() { return dns.rd; }
/**
* \brief Setter for the recursion available field.
*
* \return uint8_t containing the value of the recursion
* available field.
*/
uint8_t recursion_available() { return dns.ra; }
/**
* \brief Setter for the z desired field.
*
* \return uint8_t containing the value of the z field.
*/
uint8_t z() { return dns.z; }
/**
* \brief Setter for the authenticated data field.
*
* \return uint8_t containing the value of the authenticated
* data field.
*/
uint8_t authenticated_data() { return dns.ad; }
/**
* \brief Setter for the checking disabled field.
*
* \return uint8_t containing the value of the checking
* disabled field.
*/
uint8_t checking_disabled() { return dns.cd; }
/**
* \brief Setter for the rcode field.
*
* \return uint8_t containing the value of the rcode field.
*/
uint8_t rcode() { return dns.rcode; }
/**
* \brief Setter for the questions field.
*
* \return uint16_t containing the value of the questions field.
*/
uint16_t questions() { return dns.questions; }
/**
* \brief Setter for the answers field.
*
* \return uint16_t containing the value of the answers field.
*/
uint16_t answers() { return dns.answers; }
/**
* \brief Setter for the authority field.
*
* \return uint16_t containing the value of the authority field.
*/
uint16_t authority() { return dns.authority; }
/**
* \brief Setter for the additional field.
*
* \return uint16_t containing the value of the additional field.
*/
uint16_t additional() { return dns.additional; }
/**
* \brief Getter for the PDU's type.
*
* \return Returns the PDUType corresponding to the PDU.
*/
PDUType pdu_type() const { return PDU::DNS; }
/**
* \brief The header's size
*/
uint32_t header_size() const;
// Setters
/**
* \brief Setter for the id field.
*
@@ -114,25 +319,122 @@ namespace Tins {
* \param new_rcode The new rcode value to be set.
*/
void rcode(uint8_t new_rcode);
// Methods
/**
* \brief Add a query to perform.
*
* \param name The name to be resolved.
* \param type The type of this query.
* \param qclass The class of this query.
*/
void add_query(const std::string &name, QueryType type, QueryClass qclass);
/**
* \brief Add a query response.
*
* \param name The resolved name.
* \param type The type of this answer.
* \param qclass The class of this answer.
* \param ttl The time-to-live of this answer.
* \param ip The ip address of the resolved name.
*/
void add_answer(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, uint32_t ip);
/**
* \brief Add an authority record.
*
* \param name The resolved name.
* \param type The type of this record.
* \param qclass The class of this record.
* \param ttl The time-to-live of this record.
* \param ip The ip address of the resolved name.
*/
void add_authority(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, uint32_t ip);
/**
* \brief Add an additional record.
*
* \param name The resolved name.
* \param type The type of this record.
* \param qclass The class of this record.
* \param ttl The time-to-live of this record.
* \param ip The ip address of the resolved name.
*/
void add_additional(const std::string &name, QueryType type, QueryClass qclass,
uint32_t ttl, uint32_t ip);
private:
struct dnshdr {
uint16_t id;
uint16_t
qr:1,
opcode:4,
aa:1,
tc:1,
rd:1,
ra:1,
z:1,
ad:1,
tc:1,
aa:1,
opcode:4,
qr:1,
rcode:4,
cd:1,
rcode:4;
uint32_t questions, answers,
ad:1,
z:1,
ra:1;
uint16_t questions, answers,
authority, additional;
} __attribute__((packed));
struct Query {
std::string name;
uint16_t type, qclass;
Query(const std::string &nm, uint16_t t, uint16_t c) :
name(nm), type(t), qclass(c) {}
};
struct ResourceRecord {
struct {
uint16_t type, qclass;
uint32_t ttl;
uint16_t dlen;
uint32_t data;
} __attribute__((packed)) info;
virtual ~ResourceRecord() {}
uint32_t write(uint8_t *buffer) const;
virtual uint32_t do_write(uint8_t *buffer) const = 0;
virtual uint32_t size() const = 0;
};
struct OffsetedResourceRecord : public ResourceRecord {
uint16_t offset;
OffsetedResourceRecord(uint16_t off) : offset(off | 0xc0) {}
uint32_t do_write(uint8_t *buffer) const;
uint32_t size() const { return sizeof(info) + sizeof(offset); }
};
struct NamedResourceRecord : public ResourceRecord {
std::string name;
NamedResourceRecord(const std::string &nm) : name(nm) {}
uint32_t do_write(uint8_t *buffer) const;
uint32_t size() const { return sizeof(info) + name.size() + 1; }
};
uint32_t find_domain_name(const std::string &dname);
bool find_domain_name(const std::string &dname, const std::list<ResourceRecord*> &lst, uint16_t &out);
void parse_domain_name(const std::string &dn, std::string &out);
void write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent);
void free_list(std::list<ResourceRecord*> &lst);
uint8_t *serialize_list(const std::list<ResourceRecord*> &lst, uint8_t *buffer) const;
ResourceRecord *make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip);
dnshdr dns;
uint32_t extra_size;
std::list<Query> queries;
std::list<ResourceRecord*> ans, arity, addit;
};
};

3
include/pdu.h
View File

@@ -87,7 +87,8 @@ namespace Tins {
DHCP,
EAPOL,
RC4EAPOL,
RSNEAPOL
RSNEAPOL,
DNS
};
/** \brief PDU constructor

154
src/dns.cpp
View File

@@ -19,9 +19,36 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <cstring>
#include <iostream> //borrame
#include <cassert>
#include "dns.h"
#include "utils.h"
using std::string;
using std::list;
Tins::DNS::DNS() : PDU(255), extra_size(0) {
std::memset(&dns, 0, sizeof(dns));
}
Tins::DNS::~DNS() {
free_list(ans);
free_list(arity);
free_list(addit);
}
void Tins::DNS::free_list(std::list<ResourceRecord*> &lst) {
while(lst.size()) {
delete lst.front();
lst.pop_front();
}
}
uint32_t Tins::DNS::header_size() const {
return sizeof(dns) + extra_size;
}
void Tins::DNS::id(uint16_t new_id) {
dns.id = new_id;
@@ -66,3 +93,130 @@ void Tins::DNS::checking_disabled(uint8_t new_cd) {
void Tins::DNS::rcode(uint8_t new_rcode) {
dns.rcode = new_rcode;
}
void Tins::DNS::add_query(const string &name, QueryType type, QueryClass qclass) {
string new_str;
parse_domain_name(name, new_str);
queries.push_back(
Query(new_str,
Utils::net_to_host_s(type),
Utils::net_to_host_s(qclass))
);
extra_size += new_str.size() + 1 + (sizeof(uint16_t) << 1);
dns.questions = Utils::net_to_host_s(queries.size());
}
void Tins::DNS::add_answer(const string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ResourceRecord *res = make_record(name, type, qclass, ttl, ip);
ans.push_back(res);
dns.answers = Utils::net_to_host_s(ans.size());
}
void Tins::DNS::add_authority(const string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ResourceRecord *res = make_record(name, type, qclass, ttl, ip);
arity.push_back(res);
dns.authority = Utils::net_to_host_s(arity.size());
}
void Tins::DNS::add_additional(const string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
ResourceRecord *res = make_record(name, type, qclass, ttl, ip);
addit.push_back(res);
dns.additional = Utils::net_to_host_s(addit.size());
}
Tins::DNS::ResourceRecord *Tins::DNS::make_record(const std::string &name, QueryType type, QueryClass qclass, uint32_t ttl, uint32_t ip) {
string nm;
parse_domain_name(name, nm);
uint16_t index = find_domain_name(nm);
ResourceRecord *res;
if(index)
res = new OffsetedResourceRecord(Utils::net_to_host_s(index));
else
res = new NamedResourceRecord(nm);
res->info.type = Utils::net_to_host_s(type);
res->info.qclass = Utils::net_to_host_s(qclass);
res->info.ttl = Utils::net_to_host_l(ttl);
res->info.dlen = Utils::net_to_host_s(sizeof(uint32_t));
res->info.data = Utils::net_to_host_l(ip);
extra_size += res->size();
return res;
}
uint32_t Tins::DNS::find_domain_name(const std::string &dname) {
uint16_t index(sizeof(dnshdr));
list<Query>::const_iterator it(queries.begin());
for(; it != queries.end() && it->name != dname; ++it)
index += it->name.size() + 1 + (sizeof(uint16_t) << 1);
if(it != queries.end() ||
find_domain_name(dname, ans, index) ||
find_domain_name(dname, arity, index) ||
find_domain_name(dname, addit, index))
return index;
else
return 0;
}
bool Tins::DNS::find_domain_name(const std::string &dname, const std::list<ResourceRecord*> &lst, uint16_t &out) {
list<ResourceRecord*>::const_iterator it(lst.begin());
NamedResourceRecord *named;
while(it != lst.end()) {
named = dynamic_cast<NamedResourceRecord*>(*it);
if(named && named->name == dname)
break;
out += (*it)->size();
++it;
}
return it != lst.end();
}
void Tins::DNS::parse_domain_name(const std::string &dn, std::string &out) {
size_t last_index(0), index;
while((index = dn.find('.', last_index+1)) != string::npos) {
out.push_back(index - last_index);
out.append(dn.begin() + last_index, dn.begin() + index);
last_index = index + 1; //skip dot
}
out.push_back(dn.size() - last_index);
out.append(dn.begin() + last_index, dn.end());
}
void Tins::DNS::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent) {
assert(total_sz >= sizeof(dns) + extra_size);
std::memcpy(buffer, &dns, sizeof(dns));
buffer += sizeof(dns);
for(list<Query>::const_iterator it(queries.begin()); it != queries.end(); ++it) {
std::memcpy(buffer, it->name.c_str(), it->name.size() + 1);
buffer += it->name.size() + 1;
*((uint16_t*)buffer) = it->type;
buffer += sizeof(uint16_t);
*((uint16_t*)buffer) = it->qclass;
buffer += sizeof(uint16_t);
}
buffer = serialize_list(ans, buffer);
buffer = serialize_list(arity, buffer);
buffer = serialize_list(addit, buffer);
}
uint8_t *Tins::DNS::serialize_list(const std::list<ResourceRecord*> &lst, uint8_t *buffer) const {
for(list<ResourceRecord*>::const_iterator it(lst.begin()); it != lst.end(); ++it)
buffer += (*it)->write(buffer);
return buffer;
}
uint32_t Tins::DNS::ResourceRecord::write(uint8_t *buffer) const {
uint32_t sz(do_write(buffer));
buffer += sz;
std::memcpy(buffer, &info, sizeof(info));
return sz + sizeof(info);
}
uint32_t Tins::DNS::OffsetedResourceRecord::do_write(uint8_t *buffer) const {
std::memcpy(buffer, &offset, sizeof(offset));
return sizeof(offset);
}
uint32_t Tins::DNS::NamedResourceRecord::do_write(uint8_t *buffer) const {
std::memcpy(buffer, name.c_str(), name.size() + 1);
return name.size() + 1;
}