resolved: add a DNS client stub resolver

Let's turn resolved into a something truly useful: a fully asynchronous
DNS stub resolver that subscribes to network changes.

(More to come: caching, LLMNR, mDNS/DNS-SD, DNSSEC, IDN, NSS module)

1 files changed, 97 insertions, 0 deletions

diff --git a/src/resolve/resolved-dns-query.h b/src/resolve/resolved-dns-query.h
new file mode 100644
index 0000000000..a07f174706
--- /dev/null
+++ b/src/resolve/resolved-dns-query.h
@@ -0,0 +1,97 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+
+#include "sd-bus.h"
+#include "util.h"
+
+typedef struct DnsQuery DnsQuery;
+typedef struct DnsQueryTransaction DnsQueryTransaction;
+
+#include "resolved.h"
+#include "resolved-dns-scope.h"
+#include "resolved-dns-rr.h"
+#include "resolved-dns-packet.h"
+
+typedef enum DnsQueryState {
+        DNS_QUERY_NULL,
+        DNS_QUERY_SENT,
+        DNS_QUERY_FAILURE,
+        DNS_QUERY_SUCCESS,
+        DNS_QUERY_SKIPPED,
+        DNS_QUERY_TIMEOUT,
+        DNS_QUERY_ATTEMPTS_MAX,
+        DNS_QUERY_INVALID_REPLY,
+} DnsQueryState;
+
+struct DnsQueryTransaction {
+        DnsQuery *query;
+        DnsScope *scope;
+
+        DnsQueryState state;
+        uint16_t id;
+
+        sd_event_source *timeout_event_source;
+        unsigned n_attempts;
+
+        DnsPacket *packet;
+
+        LIST_FIELDS(DnsQueryTransaction, transactions_by_query);
+        LIST_FIELDS(DnsQueryTransaction, transactions_by_scope);
+};
+
+struct DnsQuery {
+        Manager *manager;
+
+        DnsResourceKey *keys;
+        unsigned n_keys;
+
+        DnsQueryState state;
+
+        sd_event_source *timeout_event_source;
+
+        uint16_t rcode;
+        DnsPacket *packet;
+
+        sd_bus_message *request;
+        unsigned char request_family;
+        const char *request_hostname;
+        union in_addr_union request_address;
+
+        void (*complete)(DnsQuery* q);
+
+        LIST_HEAD(DnsQueryTransaction, transactions);
+        LIST_FIELDS(DnsQuery, queries);
+};
+
+int dns_query_new(Manager *m, DnsQuery **q, DnsResourceKey *keys, unsigned n_keys);
+DnsQuery *dns_query_free(DnsQuery *q);
+int dns_query_start(DnsQuery *q);
+void dns_query_finish(DnsQuery *q);
+
+DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t);
+int dns_query_transaction_start(DnsQueryTransaction *t);
+int dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQuery*, dns_query_free);