#include <sstream>
#include <algorithm>
#include <iterator>
-#ifdef DEBUG2
+#include <sstream>
+#include <functional>
+#ifdef DEBUG
#include <iostream>
#endif
-static void parsename(const std::string& s, NameServer::name_t& name)
+#define DEBUG_RESOLV
+
+NameServer::Name::Name(const std::string& s)
{
std::istringstream iss(s);
std::string tok;
while (std::getline(iss, tok, '.'))
- {
- name.push_back(tok);
- }
+ push_back(tok);
}
-static std::ostream& operator<< (std::ostream& os, const NameServer::name_t& name)
+std::ostream& operator<< (std::ostream& os, const NameServer::Name& name)
{
if (name.empty())
return os;
return os << name.back();
}
+NameServer::Name::operator std::string ()
+{
+ std::stringstream ss;
+ ss << *this;
+ return ss.str();
+}
+
/// Parsea una zona
static std::istream& parsezone(std::istream& is, NameServer::Zone& z)
throw (std::runtime_error)
std::istringstream iss(line);
if (!(iss >> sname >> z.ttl >> ip))
throw std::runtime_error("Error al parsear");
- parsename(sname, z.name);
-#ifdef DEBUG2
+ z.name = sname;
+#ifdef DEBUG_PARSER
std::cerr << "parsezone: IP = " << ip << "\n\n";
#endif
z.parent = IPAddr(ip);
if (!(iss >> key >> type >> ip))
throw std::runtime_error("Error al parsear");
typedef NameServer::Record Rec;
-#ifdef DEBUG2
+#ifdef DEBUG_PARSER
std::cerr << "parsezone: IP = " << ip << "\n\n";
#endif
Rec r((type == "NS") ? Rec::NS : Rec::A, IPAddr(ip));
z.records.insert(NameServer::Zone::records_t::value_type(key, r));
}
-#ifdef DEBUG2
+#ifdef DEBUG_PARSER
std::cerr << "parsezone: " << z << "\n\n";
#endif
return is;
/// Constructor
NameServer::Zone::Zone(std::string sname, size_t ttl, const IPAddr& parent):
- ttl(ttl), parent(parent)
+ name(sname), ttl(ttl), parent(parent)
{
- parsename(sname, name);
}
/// Constructor
{
zones.push_back(z);
z.clear();
-#ifdef DEBUG2
+#ifdef DEBUG_PARSER
std::cerr << "NameServer: " << z << "\n\n";
#endif
}
}
-std::ostream& operator<< (std::ostream& os, const NameServer::Record& r)
+/// Devuelve la parte izquierda de n, si la parte derecha coincide exactamente
+/// con m, si no devuelve un vector vacío.
+/// Elemplo: name_split("mi.domi.nio", "domi.nio") == ["mi"]
+/// name_split("dos.mi.domi.nio", "domi.nio") == ["dos", "mi"]
+/// name_split("domi.nio", "domi.nio") == []
+/// name_split("papeli.nio", "domi.nio") == []
+static NameServer::Name
+name_split(NameServer::Name n, NameServer::Name m)
+{
+ NameServer::Name r;
+ std::reverse(n.begin(), n.end());
+ std::reverse(m.begin(), m.end());
+ // Si m es más grande o igual que n, no hay nada que hacer
+ if (n.size() <= m.size())
+ return r;
+ // Si no coincide la parte derecha, no hay nada que hacer
+ NameServer::Name::size_type i;
+ for (i = 0; i < m.size(); ++i)
+ if (n[i] != m[i])
+ return r;
+ // Si era todo igual y sobran cosas, devolvemos lo que "sobra"
+ while (i < n.size())
+ r.push_back(n[i++]);
+ std::reverse(r.begin(), r.end());
+#ifdef DEBUG_NAME
+ std::cerr << "name_split(" << n << ", " << m << ") -> " << r << "\n";
+#endif
+ return r;
+}
+
+/// Devuelve -1 si es un nombre "hijo" (la parte derecha de n está contenida
+/// completamente en m, pero m y n no son iguales), 0 si m == n y 1 si es
+/// "padre" (m no coincide con la parte derecha de n).
+/// Elemplo: namecmp("mi.domi.nio", "domi.nio") == -1
+/// namecmp("otra.cosa", "domi.nio") == 1
+/// namecmp("papeli.nio", "domi.nio") == 1
+/// namecmp("domi.nio", "domi.nio") == 0
+/*enum name_cmp_t
+{
+ NC_DIRECT_CHILD, ///> Hijo directo, es decir, está en la zona m
+ NC_CHILD, ///> Hijo indirecto, está en una zona que cuelga de m
+ NC_EQUAL, ///> Es el host de la zona m
+ NC_DIRECT_PARENT, ///> Padre directo, es decir, coincide en parte con m
+ NC_PARENT ///> Padre indirecto, es completamente distinto a m
+};*/
+#if 0
+static int name_cmp(const NameServer::Name& n, const NameServer::Name& m)
+{
+ // Si m es más grande que n, seguro es padre
+ if (n.size() < m.size())
+ return 1;
+ // Si no coincide la parte derecha, seguro es padre
+ NameServer::Name::size_type i;
+ for (i = m.size(); i > 0; --i)
+ if (n[i-1] != m[i-1])
+ return 1;
+ // Si era todo igual y sobran cosas, es hijo
+ if (i)
+ return -1;
+ // Si no, son iguales.
+ return 0;
+}
+#endif
+
+struct search_zone: std::unary_function< NameServer::Zone, bool >
+{
+ bool local;
+ NameServer::CacheRecord crecord;
+ const NameServer::Name& name;
+ search_zone(const NameServer::Name& n): local(false), name(n) {}
+ bool operator() (const NameServer::Zone& z)
+ {
+ bool found = false;
+ NameServer::Name local_part = name_split(name, z.name);
+ if (!local_part.empty()) // Está en esta zona
+ {
+ local = true;
+ std::string n = local_part.back(); // Obtengo última parte
+ // busco
+ typedef NameServer::Zone::records_t::const_iterator itt;
+ std::pair<itt, itt> p = z.records.equal_range(n);
+ for (; p.first != p.second; ++p.first)
+ {
+ const NameServer::Record& r = (*p.first).second;
+ // Tiene que buscar solo A porque era un nombre
+ if ((local_part.size() == 1) && (r.type != NameServer::Record::A))
+ continue;
+ // Tiene que seguir para abajo, solo busca NS
+ if ((local_part.size() > 1) && r.type != NameServer::Record::NS)
+ continue;
+ found = true;
+ crecord.ttl = z.ttl;
+ crecord.records.push_back(r);
+ }
+ }
+ return found;
+ }
+};
+
+void NameServer::resolv_next(const Name& n)
+{
+#ifdef DEBUG_RESOLV
+ std::cerr<< "resolv_next -> tratando de resolver: " << n << "\n";
+#endif
+ search_zone zs(n);
+ bool found;
+ for (zones_t::const_iterator i = zones.begin(); i!= zones.end(); ++i)
+ if ((found = zs(*i)))
+ break;
+ if (found)
+ {
+ // TODO mandar resultados?
+#ifdef DEBUG_RESOLV
+ std::cerr<< "resolv_next found (local/hijo): " << zs.crecord << "\n";
+#endif
+ return;
+ }
+ if (zs.local)
+ {
+ // TODO mandar NOT FOUND
+#ifdef DEBUG_RESOLV
+ std::cerr<< "resolv_next NOT FOUND (es local pero no existe)\n";
+#endif
+ return;
+ }
+ cache_t::const_iterator i = cache.find(n);
+ if (i != cache.end())
+ {
+ // TODO mandar resultados?
+#ifdef DEBUG_RESOLV
+ std::cerr<< "resolv_next found (en cache): " << i->second << "\n";
+#endif
+ return;
+ }
+ // TODO enviar nameserver padre, si no hay padre, mandar NOT FOUND
+ if (zones.size())
+ {
+#ifdef DEBUG_RESOLV
+ std::cerr << "resolv_next found (al padre): " << zones.front().parent
+ << "\n";
+ return;
+#endif
+ }
+ // TODO enviar NOT FOUND
+#ifdef DEBUG_RESOLV
+ std::cerr<< "resolv_next NOT FOUND (no hay padre)\n";
+#endif
+}
+
+std::ostream& operator<< (std::ostream& os, const NameServer::Record::type_t& t)
{
- if (r.type == NameServer::Record::NS)
- os << "NS ";
+ if (t == NameServer::Record::NS)
+ return os << "NS";
else
- os << "A ";
- return os << r.ip;
+ return os << "A";
+}
+
+std::ostream& operator<< (std::ostream& os, const NameServer::Record& r)
+{
+ return os << r.type << " " << r.ip;
}
std::ostream& operator<< (std::ostream& os,
return os;
}
+std::ostream& operator<< (std::ostream& os, const NameServer::CacheRecord& cr)
+{
+ os << "CacheRecord(ttl=" << cr.ttl << ", records=";
+ std::copy(cr.records.begin(), cr.records.end(),
+ std::ostream_iterator< NameServer::Record >(os, ","));
+ return os << ")";
+}
+
std::ostream& operator<< (std::ostream& os, const NameServer& ns)
{
os << "NameServer: zones[" << ns.zones.size() << "] (\n\n";
{
/// Nombre de un dominio dividido en tokens
- typedef std::vector< std::string > name_t;
+ struct Name: std::vector< std::string >
+ {
+ /// Constructor
+ Name() {}
+ Name(const std::string& name);
+ operator std::string ();
+ };
/// Registro de una zona
struct Record
struct Zone
{
/// Nombre
- name_t name;
+ Name name;
/// Time to live
size_t ttl;
/// Nodo padre
void clear();
};
- //TODO cache de _records_ (no zonas)
-
/// Zonas para las que este servidor de nombres es autoridad
typedef std::vector< Zone > zones_t;
zones_t zones;
+ /// Cache de un registro
+ struct CacheRecord
+ {
+ /// Time to live
+ size_t ttl;
+ /// Dirección IP del registro
+ typedef std::vector< Record > records_t;
+ records_t records;
+ /// Constructor
+ CacheRecord(): ttl(0) {}
+ CacheRecord(size_t ttl, const records_t& records):
+ ttl(ttl), records(records) {}
+ };
+
+ /// Cache de records
+ typedef std::map< Name, CacheRecord > cache_t;
+ cache_t cache;
+
/// Constructor
NameServer(std::istream& is) throw (std::runtime_error);
+ /// Resuelve un nombre de forma no recursiva
+ void resolv_next(const Name& n);
};
/// Impresión (para debug)
std::ostream& operator<< (std::ostream& os, const NameServer& ns);
+std::ostream& operator<< (std::ostream& os, const NameServer::Name& name);
std::ostream& operator<< (std::ostream& os, const NameServer::Record& r);
std::ostream& operator<< (std::ostream& os, const NameServer::Zone& z);
+std::ostream& operator<< (std::ostream& os, const NameServer::CacheRecord& cr);
#endif // _NAMESERVER_H_
projects / z.facultad / 75.74 / practicos.git / commitdiff