Se mejora el redireccionado al padre, se usan solo padres no nulos.

[z.facultad/75.74/practicos.git] / practicas / pipi / src / nameserver.cpp

diff --git a/practicas/pipi/src/nameserver.cpp b/practicas/pipi/src/nameserver.cpp
index 1e6e19c323097a33e6ad1949bf621345f776145f..cf7dac33208141847e82138977b0f5d2902c326c 100644 (file)
--- a/practicas/pipi/src/nameserver.cpp
+++ b/practicas/pipi/src/nameserver.cpp
@@ -211,10 +211,11 @@ struct search_zone: std::unary_function< NameServer::Zone, bool >
     }
 };
 
-ResolvProtoResponse NameServer::resolv_next(const Name& n)
+/// Resuelve un nombre de forma directa (no recursiva)
+ResolvProtoResponse NameServer::resolv_direct(const Name& n)
 {
 #ifdef DEBUG_RESOLV
-    std::cerr << "resolv_next -> tratando de resolver: " << n << "\n";
+    std::cerr << "resolv_direct -> tratando de resolver: " << n << "\n";
 #endif
     search_zone zs(n);
     bool found;
@@ -224,14 +225,14 @@ ResolvProtoResponse NameServer::resolv_next(const Name& n)
     if (found)
     {
 #ifdef DEBUG_RESOLV
-        std::cerr << "resolv_next found (local/hijo): " << zs.resp << "\n";
+        std::cerr << "resolv_direct found (local/hijo): " << zs.resp << "\n";
 #endif
         return zs.resp;
     }
     if (zs.local)
     {
 #ifdef DEBUG_RESOLV
-        std::cerr << "resolv_next NOT FOUND (es local pero no existe)\n";
+        std::cerr << "resolv_direct NOT FOUND (es local pero no existe)\n";
 #endif
         return ResolvProtoResponse(ResolvProtoResponse::R_NOTFOUND);
     }
@@ -240,27 +241,129 @@ ResolvProtoResponse NameServer::resolv_next(const Name& n)
     if (i != cache.end())
     {
 #ifdef DEBUG_RESOLV
-        std::cerr << "resolv_next found (en cache): " << i->second << "\n";
+        std::cerr << "resolv_direct found (en cache): " << i->second << "\n";
 #endif
         const CacheRecord& cr = i->second;
         return ResolvProtoResponse(ResolvProtoResponse::R_A, cr.ttl, cr.ips);
     }
     if (zones.size())
     {
+        // Busco una zona con padre para ver si puedo "trepar"
+        for (zones_t::const_iterator i = zones.begin(); i != zones.end(); ++i)
+        {
 #ifdef DEBUG_RESOLV
-        std::cerr << "resolv_next found (al padre): " << zones.front().parent
+            std::cerr << "resolv_direct -> evaluando padre " << i->parent
                 << "\n";
-        ResolvProtoResponse rpr(ResolvProtoResponse::R_NS, zones.front().ttl);
-        rpr.ips.push_back(zones.front().parent);
-        return rpr;
 #endif
+            if (i->parent != IPAddr(0))
+            {
+#ifdef DEBUG_RESOLV
+                std::cerr << "resolv_direct found (al padre): "
+                    << i->parent << "\n";
+#endif
+                ResolvProtoResponse rpr(ResolvProtoResponse::R_NS, i->ttl);
+                rpr.ips.push_back(i->parent);
+                return rpr;
+            }
+        }
     }
 #ifdef DEBUG_RESOLV
-    std::cerr << "resolv_next NOT FOUND (no hay padre)\n";
+    std::cerr << "resolv_direct NOT FOUND (no hay padre)\n";
 #endif
+    // No hay padre, no puedo hacer nada más
     return ResolvProtoResponse(ResolvProtoResponse::R_NOTFOUND);
 }
 
+/// Resuelve un nombre de forma recursiva
+ResolvProtoResponse NameServer::resolv_recursive(const Name& n)
+{
+    ResolvProtoResponse rpr = resolv_direct(n);
+    switch (rpr.ret)
+    {
+        case ResolvProtoResponse::R_NS:
+#ifdef DEBUG_RESOLV
+            std::cerr << "resolv_recursive -> redirect a " << rpr << "\n";
+#endif
+            return resolv_recursive_r(n, rpr); // Sigo "bajando"
+        case ResolvProtoResponse::R_A:
+#ifdef DEBUG_RESOLV
+            std::cerr << "resolv_recursive -> gotcha! " << rpr << "\n";
+#endif
+            // TODO agregar a cache
+            break;
+    }
+    return rpr; // Devuelvo el A o NOTFOUND
+}
+
+/// Resuelve un nombre de forma recursiva entrando a otros ns
+ResolvProtoResponse NameServer::resolv_recursive_r(const Name& n,
+        ResolvProtoResponse rpr)
+{
+    ResolvProtoResponse r;
+    for (ResolvProtoResponse::ipvec_t::const_iterator ip = rpr.ips.begin();
+            ip != rpr.ips.end(); ++ip)
+    {
+        r = query(n, *ip);
+        switch (r.ret)
+        {
+            case ResolvProtoResponse::R_NS:
+#ifdef DEBUG_RESOLV
+                std::cerr << "resolv_recursive_r -> redirect a " << r << "\n";
+#endif
+                return resolv_recursive_r(n, r); // Sigo "bajando"
+            case ResolvProtoResponse::R_NOTFOUND:
+#ifdef DEBUG_RESOLV
+                std::cerr << "resolv_recursive_r -> NOT FOUND en " << *ip
+                    << ", sigo probando\n";
+#endif
+                break; // Sigo probando del mismo nivel
+            case ResolvProtoResponse::R_A:
+#ifdef DEBUG_RESOLV
+                std::cerr << "resolv_recursive_r -> gotcha! " << r << "\n";
+#endif
+                // TODO agregar a cache
+                return r; // Gotcha!
+        }
+    }
+#ifdef DEBUG_RESOLV
+    std::cerr << "resolv_recursive_r -> NOT FOUND, no hay más por hacer\n";
+#endif
+    return r; // NOTFOUND
+}
+
+/// Consulta a otro name server sobre un nombre
+ResolvProtoResponse NameServer::query(const Name& n, const IPAddr& ip)
+{
+    // TODO IMPLEMENTAR!!!
+#ifdef DEBUG_RESOLV
+    std::cerr << "query -> Haciendo query dummy\n";
+#endif
+    if (ip == IPAddr("10.10.10.1"))
+    {
+        ResolvProtoResponse r(ResolvProtoResponse::R_NS, 500);
+        r.ips.push_back(IPAddr("10.10.10.2"));
+        r.ips.push_back(IPAddr("10.10.10.3"));
+        return r;
+    }
+    else if (ip == IPAddr("10.10.10.2"))
+    {
+        return ResolvProtoResponse(ResolvProtoResponse::R_NOTFOUND);
+    }
+    else if (ip == IPAddr("10.10.10.3"))
+    {
+        ResolvProtoResponse r(ResolvProtoResponse::R_NS, 666);
+        r.ips.push_back(IPAddr("10.10.10.4"));
+        return r;
+    }
+    else
+    {
+        ResolvProtoResponse r(ResolvProtoResponse::R_A, 1500);
+        r.ips.push_back(IPAddr("10.10.10.5"));
+        r.ips.push_back(IPAddr("10.10.10.6"));
+        return r;
+    }
+}
+
 std::ostream& operator<< (std::ostream& os, const NameServer::Record::type_t& t)
 {
     if (t == NameServer::Record::NS)