resolved: when rereading /etc/resolv.conf, always start using first DNS server again

[elogind.git] / src / resolve / resolved-dns-server.c

diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
index 07754a0bdb436174fe388b9badec354b3915b661..caf06fe4506781945a6f37ad040fc4bd2fcf984f 100644 (file)
--- a/src/resolve/resolved-dns-server.c
+++ b/src/resolve/resolved-dns-server.c
@@ -19,48 +19,55 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include "siphash24.h"
+
 #include "resolved-dns-server.h"
 
 int dns_server_new(
                 Manager *m,
                 DnsServer **ret,
-                DnsServerSource source,
+                DnsServerType type,
                 Link *l,
-                unsigned char family,
+                int family,
                 const union in_addr_union *in_addr) {
 
         DnsServer *s, *tail;
 
         assert(m);
+        assert((type == DNS_SERVER_LINK) == !!l);
         assert(in_addr);
-        assert(source < _DNS_SERVER_SOURCE_MAX);
 
         s = new0(DnsServer, 1);
         if (!s)
                 return -ENOMEM;
 
-        s->source = source;
+        s->type = type;
         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);
+        if (type == DNS_SERVER_LINK) {
+                LIST_FIND_TAIL(servers, l->dns_servers, tail);
+                LIST_INSERT_AFTER(servers, l->dns_servers, tail, s);
                 s->link = l;
-        } else {
-                assert(!l);
+        } else if (type == DNS_SERVER_SYSTEM) {
                 LIST_FIND_TAIL(servers, m->dns_servers, tail);
                 LIST_INSERT_AFTER(servers, m->dns_servers, tail, s);
-        }
+        } else if (type == DNS_SERVER_FALLBACK) {
+                LIST_FIND_TAIL(servers, m->fallback_dns_servers, tail);
+                LIST_INSERT_AFTER(servers, m->fallback_dns_servers, tail, s);
+        } else
+                assert_not_reached("Unknown server type");
 
         s->manager = m;
 
+        /* A new DNS server that isn't fallback is added and the one
+         * we used so far was a fallback one? Then let's try to pick
+         * the new one */
+        if (type != DNS_SERVER_FALLBACK &&
+            m->current_dns_server &&
+            m->current_dns_server->type == DNS_SERVER_FALLBACK)
+                manager_set_dns_server(m, NULL);
+
         if (ret)
                 *ret = s;
 
@@ -71,28 +78,50 @@ 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)
+        if (s->manager) {
+                if (s->type == DNS_SERVER_LINK)
+                        LIST_REMOVE(servers, s->link->dns_servers, s);
+                else if (s->type == DNS_SERVER_SYSTEM)
                         LIST_REMOVE(servers, s->manager->dns_servers, s);
+                else if (s->type == DNS_SERVER_FALLBACK)
+                        LIST_REMOVE(servers, s->manager->fallback_dns_servers, s);
+                else
+                        assert_not_reached("Unknown server type");
+
+                if (s->manager->current_dns_server == s)
+                        manager_set_dns_server(s->manager, NULL);
         }
 
         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;
+                link_set_dns_server(s->link, NULL);
 
         free(s);
 
         return NULL;
 }
+
+static unsigned long dns_server_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+        const DnsServer *s = p;
+        uint64_t u;
+
+        siphash24((uint8_t*) &u, &s->address, FAMILY_ADDRESS_SIZE(s->family), hash_key);
+        u = u * hash_key[0] + u + s->family;
+
+        return u;
+}
+
+static int dns_server_compare_func(const void *a, const void *b) {
+        const DnsServer *x = a, *y = b;
+
+        if (x->family < y->family)
+                return -1;
+        if (x->family > y->family)
+                return 1;
+
+        return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
+}
+
+const struct hash_ops dns_server_hash_ops = {
+        .hash = dns_server_hash_func,
+        .compare = dns_server_compare_func
+};