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, 98 insertions, 0 deletions

diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
new file mode 100644
index 0000000000..4e0220b7d8
--- /dev/null
+++ b/src/resolve/resolved-dns-server.c
@@ -0,0 +1,98 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  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 "resolved-dns-server.h"
+
+int dns_server_new(
+                Manager *m,
+                DnsServer **ret,
+                DnsServerSource source,
+                Link *l,
+                unsigned char family,
+                union in_addr_union *in_addr) {
+
+        DnsServer *s, *tail;
+
+        assert(m);
+        assert(in_addr);
+        assert(source < _DNS_SERVER_SOURCE_MAX);
+
+        s = new0(DnsServer, 1);
+        if (!s)
+                return -ENOMEM;
+
+        s->source = source;
+        s->family = family;
+        s->address = *in_addr;
+
+        if (source == DNS_SERVER_LINK) {
+                assert(l);
+                LIST_FIND_TAIL(servers, l->link_dns_servers, tail);
+                LIST_INSERT_AFTER(servers, l->link_dns_servers, tail, s);
+                s->link = l;
+        } else if (source == DNS_SERVER_DHCP) {
+                assert(l);
+                LIST_FIND_TAIL(servers, l->dhcp_dns_servers, tail);
+                LIST_INSERT_AFTER(servers, l->dhcp_dns_servers, tail, s);
+                s->link = l;
+        } else {
+                assert(!l);
+                LIST_FIND_TAIL(servers, m->dns_servers, tail);
+                LIST_INSERT_AFTER(servers, m->dns_servers, tail, s);
+        }
+
+        s->manager = m;
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+DnsServer* dns_server_free(DnsServer *s)  {
+        if (!s)
+                return NULL;
+
+        if (s->source == DNS_SERVER_LINK) {
+
+                if (s->link)
+                        LIST_REMOVE(servers, s->link->link_dns_servers, s);
+        } else if (s->source == DNS_SERVER_DHCP) {
+
+                if (s->link)
+                        LIST_REMOVE(servers, s->link->dhcp_dns_servers, s);
+
+        } else if (s->source == DNS_SERVER_SYSTEM) {
+
+                if (s->manager)
+                        LIST_REMOVE(servers, s->manager->dns_servers, s);
+        }
+
+        if (s->link && s->link->current_dns_server == s)
+                s->link->current_dns_server = NULL;
+
+        if (s->manager && s->manager->current_dns_server == s)
+                s->manager->current_dns_server = NULL;
+
+        free(s);
+
+        return NULL;
+}