[Feature] Rework librdns to interact with external upstreams

diff --git a/contrib/librdns/dns_private.h b/contrib/librdns/dns_private.h
index 76e32496d6dacce333234f745253967c8fe7444b..28ab60a596e98168f2fe1169a554563eab5f3832 100644 (file)
--- a/contrib/librdns/dns_private.h
+++ b/contrib/librdns/dns_private.h
@@ -51,6 +51,7 @@ struct rdns_server {
        unsigned int io_cnt;
 
        struct rdns_io_channel **io_channels;
+       void *ups_elt;
        upstream_entry_t up;
 };
 
@@ -112,7 +113,7 @@ struct rdns_resolver {
        struct rdns_io_channel *io_channels; /**< hash of io chains indexed by socket        */
        struct rdns_async_context *async; /** async callbacks */
        void *periodic; /** periodic event for resolver */
-
+       struct rdns_upstream_context *ups;
        struct rdns_plugin *curve_plugin;
 
        rdns_log_function logger;

diff --git a/contrib/librdns/rdns.h b/contrib/librdns/rdns.h
index a1cfad4d31c6a2d1c4e0d7a4e28bd1a4b4129fa5..0728e5b9cbb34c364cd7860617a02976cfdc5396 100644 (file)
--- a/contrib/librdns/rdns.h
+++ b/contrib/librdns/rdns.h
@@ -126,7 +126,7 @@ enum dns_rcode {
        RDNS_RC_NETERR = 12,
        RDNS_RC_NOREC = 13
 };
-       
+
 struct rdns_reply {
        struct rdns_request *request;
        struct rdns_resolver *resolver;
@@ -152,11 +152,26 @@ struct rdns_async_context {
        void (*cleanup)(void *priv_data);
 };
 
+struct rdns_upstream_elt {
+       void *server;
+       void *lib_data;
+};
+
+struct rdns_upstream_context {
+       void *data;
+       struct rdns_upstream_elt* (*select)(const char *name,
+                       size_t len, void *ups_data);
+       struct rdns_upstream_elt* (*select_retransmit)(const char *name,
+                       size_t len, void *ups_data);
+       void (*ok)(struct rdns_upstream_elt *elt, void *ups_data);
+       void (*fail)(struct rdns_upstream_elt *elt, void *ups_data);
+};
+
 /**
  * Type of rdns plugin
  */
 enum rdns_plugin_type {
-       RDNS_PLUGIN_CURVE = 0//!< use the specified plugin instead of send/recv functions
+       RDNS_PLUGIN_CURVE = 0
 };
 
 typedef ssize_t (*rdns_network_send_callback) (struct rdns_request *req, void *plugin_data);
@@ -226,9 +241,9 @@ void rdns_resolver_async_bind (struct rdns_resolver *resolver,
  * @param name name of DNS server (should be ipv4 or ipv6 address)
  * @param priority priority (can be 0 for fair round-robin)
  * @param io_cnt a number of sockets that are simultaneously opened to this server
- * @return true if a server has been added to resolver
+ * @return opaque pointer that could be used to select upstream
  */
-bool rdns_resolver_add_server (struct rdns_resolver *resolver,
+void* rdns_resolver_add_server (struct rdns_resolver *resolver,
                const char *name, unsigned int port,
                int priority, unsigned int io_cnt);
 
@@ -259,6 +274,15 @@ void rdns_resolver_set_logger (struct rdns_resolver *resolver,
 void rdns_resolver_set_log_level (struct rdns_resolver *resolver,
                enum rdns_log_level level);
 
+/**
+ * Set upstream library for selecting DNS upstreams
+ * @param resolver resolver object
+ * @param ups_ctx upstream functions
+ * @param ups_data opaque data
+ */
+void rdns_resolver_set_upstream_lib (struct rdns_resolver *resolver,
+               struct rdns_upstream_context *ups_ctx,
+               void *ups_data);
 
 /**
  * Set maximum number of dns requests to be sent to a socket to be refreshed

diff --git a/contrib/librdns/resolver.c b/contrib/librdns/resolver.c
index 9741f7bf9b484345fbee9d3a1a823b002205ba0e..4027bf0ab79ec0c9730a2979fc2603e762c45691 100644 (file)
--- a/contrib/librdns/resolver.c
+++ b/contrib/librdns/resolver.c
@@ -87,13 +87,13 @@ rdns_send_request (struct rdns_request *req, int fd, bool new_req)
                         * should take care about events processing
                         */
                        return 0;
-               } 
+               }
                else {
                        rdns_debug ("send failed: %s for server %s", strerror (errno), serv->name);
                        return -1;
                }
        }
-       
+
        if (new_req) {
                /* Add request to hash table */
                HASH_ADD_INT (req->io->requests, id, req);
@@ -131,7 +131,7 @@ rdns_find_dns_request (uint8_t *in, struct rdns_io_channel *ioc)
        struct rdns_request *req;
        int id;
        struct rdns_resolver *resolver = ioc->resolver;
-       
+
        id = header->qid;
        HASH_FIND_INT (ioc->requests, &id, req);
        if (req == NULL) {
@@ -170,7 +170,7 @@ rdns_parse_reply (uint8_t *in, int r, struct rdns_request *req,
                return false;
        }
 
-       /* 
+       /*
         * Now we have request and query data is now at the end of header, so compare
         * request QR section and reply QR section
         */
@@ -221,7 +221,7 @@ rdns_parse_reply (uint8_t *in, int r, struct rdns_request *req,
                        }
                }
        }
-       
+
        if (!found && type != RDNS_REQUEST_ANY) {
                /* We have not found the requested RR type */
                rep->code = RDNS_RC_NOREC;
@@ -251,7 +251,7 @@ rdns_process_read (int fd, void *arg)
        uint8_t in[UDP_PACKET_SIZE];
 
        resolver = ioc->resolver;
-       
+
        /* First read packet from socket */
        if (resolver->curve_plugin == NULL) {
                r = read (fd, in, sizeof (in));
@@ -271,6 +271,12 @@ rdns_process_read (int fd, void *arg)
        if (req != NULL) {
                if (rdns_parse_reply (in, r, req, &rep)) {
                        UPSTREAM_OK (req->io->srv);
+
+                       if (req->resolver->ups && req->io->srv->ups_elt) {
+                               req->resolver->ups->ok (req->io->srv->ups_elt,
+                                               req->resolver->ups->data);
+                       }
+
                        req->state = RDNS_REQUEST_REPLIED;
                        rdns_request_unschedule (req);
                        req->func (rep, req->arg);
@@ -297,7 +303,14 @@ rdns_process_timer (void *arg)
        resolver = req->resolver;
 
        if (req->retransmits == 0) {
-               UPSTREAM_FAIL (req->io->srv, time (NULL));
+               if (req->resolver->ups && req->io->srv->ups_elt) {
+                       req->resolver->ups->fail (req->io->srv->ups_elt,
+                                       req->resolver->ups->data);
+               }
+               else {
+                       UPSTREAM_FAIL (req->io->srv, time (NULL));
+               }
+
                rep = rdns_make_reply (req, RDNS_RC_TIMEOUT);
                req->state = RDNS_REQUEST_REPLIED;
                rdns_request_unschedule (req);
@@ -307,13 +320,29 @@ rdns_process_timer (void *arg)
                return;
        }
 
-       if (!req->io->active) {
+       if (!req->io->active || req->retransmits == 1) {
                /* Do not reschedule IO requests on inactive sockets */
                rdns_debug ("reschedule request with id: %d", (int)req->id);
                rdns_request_unschedule (req);
                REF_RELEASE (req->io);
 
-               UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+               if (resolver->ups) {
+                       struct rdns_upstream_elt *elt;
+
+                       elt = resolver->ups->select_retransmit (req->requested_names[0].name,
+                                       req->requested_names[0].len, resolver->ups->data);
+
+                       if (elt) {
+                               serv = elt->server;
+                               serv->ups_elt = elt;
+                       }
+                       else {
+                               UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+                       }
+               }
+               else {
+                       UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+               }
 
                if (serv == NULL) {
                        rdns_warn ("cannot find suitable server for request");
@@ -340,7 +369,14 @@ rdns_process_timer (void *arg)
                req->state = RDNS_REQUEST_REGISTERED;
        }
        else if (r == -1) {
-               UPSTREAM_FAIL (req->io->srv, time (NULL));
+               if (req->resolver->ups && req->io->srv->ups_elt) {
+                       req->resolver->ups->fail (req->io->srv->ups_elt,
+                                       req->resolver->ups->data);
+               }
+               else {
+                       UPSTREAM_FAIL (req->io->srv, time (NULL));
+               }
+
                rep = rdns_make_reply (req, RDNS_RC_NETERR);
                req->state = RDNS_REQUEST_REPLIED;
                rdns_request_unschedule (req);
@@ -426,7 +462,14 @@ rdns_process_retransmit (int fd, void *arg)
                req->state = RDNS_REQUEST_REGISTERED;
        }
        else if (r == -1) {
-               UPSTREAM_FAIL (req->io->srv, time (NULL));
+               if (req->resolver->ups && req->io->srv->ups_elt) {
+                       req->resolver->ups->fail (req->io->srv->ups_elt,
+                                       req->resolver->ups->data);
+               }
+               else {
+                       UPSTREAM_FAIL (req->io->srv, time (NULL));
+               }
+
                rep = rdns_make_reply (req, RDNS_RC_NETERR);
                req->state = RDNS_REQUEST_REPLIED;
                req->func (rep, req->arg);
@@ -487,7 +530,7 @@ rdns_make_request_full (
        req->curve_plugin_data = NULL;
 #endif
        REF_INIT_RETAIN (req, rdns_request_free);
-       
+
        /* Calculate packet's total length based on records count */
        va_start (args, queries);
        for (i = 0; i < queries * 2; i += 2) {
@@ -554,18 +597,34 @@ rdns_make_request_full (
        req->state = RDNS_REQUEST_NEW;
        req->async = resolver->async;
 
-       UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+       if (resolver->ups) {
+               struct rdns_upstream_elt *elt;
+
+               elt = resolver->ups->select (req->requested_names[0].name,
+                               req->requested_names[0].len, resolver->ups->data);
+
+               if (elt) {
+                       serv = elt->server;
+                       serv->ups_elt = elt;
+               }
+               else {
+                       UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+               }
+       }
+       else {
+               UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+       }
 
        if (serv == NULL) {
                rdns_warn ("cannot find suitable server for request");
                REF_RELEASE (req);
                return NULL;
        }
-       
+
        /* Select random IO channel */
        req->io = serv->io_channels[ottery_rand_uint32 () % serv->io_cnt];
        req->io->uses ++;
-       
+
        /* Now send request to server */
        r = rdns_send_request (req, req->io->sock, true);
 
@@ -590,7 +649,7 @@ rdns_resolver_init (struct rdns_resolver *resolver)
        if (!resolver->async_binded) {
                return false;
        }
-       
+
        if (resolver->servers == NULL) {
                return false;
        }
@@ -644,7 +703,7 @@ rdns_resolver_register_plugin (struct rdns_resolver *resolver,
        }
 }
 
-bool
+void *
 rdns_resolver_add_server (struct rdns_resolver *resolver,
                const char *name, unsigned int port,
                int priority, unsigned int io_cnt)
@@ -658,24 +717,24 @@ rdns_resolver_add_server (struct rdns_resolver *resolver,
        if (inet_pton (AF_INET, name, &addr) == 0 &&
                inet_pton (AF_INET6, name, &addr) == 0) {
                /* Invalid IP */
-               return false;
+               return NULL;
        }
 
        if (io_cnt == 0) {
-               return false;
+               return NULL;
        }
        if (port == 0 || port > UINT16_MAX) {
-               return false;
+               return NULL;
        }
 
        serv = calloc (1, sizeof (struct rdns_server));
        if (serv == NULL) {
-               return false;
+               return NULL;
        }
        serv->name = strdup (name);
        if (serv->name == NULL) {
                free (serv);
-               return false;
+               return NULL;
        }
 
        serv->io_cnt = io_cnt;
@@ -683,7 +742,7 @@ rdns_resolver_add_server (struct rdns_resolver *resolver,
 
        UPSTREAM_ADD (resolver->servers, serv, priority);
 
-       return true;
+       return serv;
 }
 
 void
@@ -701,6 +760,15 @@ rdns_resolver_set_log_level (struct rdns_resolver *resolver,
        resolver->log_level = level;
 }
 
+void
+rdns_resolver_set_upstream_lib (struct rdns_resolver *resolver,
+               struct rdns_upstream_context *ups_ctx,
+               void *ups_data)
+{
+       resolver->ups = ups_ctx;
+       resolver->ups->data = ups_data;
+}
+
 
 void
 rdns_resolver_set_max_io_uses (struct rdns_resolver *resolver,