resolved: when picking a new hostname make sure two hosts pick different ones

[elogind.git] / src / resolve / resolved-manager.c

diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index db346cc0e54ff5abe63c99570eb37a8a6f516ced..988aa6e3b1a2fec802c848fddb84bef0345c9d9c 100644 (file)
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -77,6 +77,10 @@ static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userda
                 if (r < 0)
                         goto fail;
 
+                r = link_update_monitor(l);
+                if (r < 0)
+                        goto fail;
+
                 if (is_new)
                         log_debug("Found new link %i/%s", ifindex, l->name);
 
@@ -550,6 +554,7 @@ Manager *manager_free(Manager *m) {
 
         manager_llmnr_stop(m);
 
+        sd_bus_slot_unref(m->prepare_for_sleep_slot);
         sd_event_source_unref(m->bus_retry_event_source);
         sd_bus_unref(m->bus);
 
@@ -1215,38 +1220,34 @@ static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *u
         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
         DnsTransaction *t = NULL;
         Manager *m = userdata;
+        DnsScope *scope;
         int r;
 
         r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p);
         if (r <= 0)
                 return r;
 
+        scope = manager_find_scope(m, p);
+        if (!scope) {
+                log_warning("Got LLMNR UDP packet on unknown scope. Ignoring.");
+                return 0;
+        }
+
         if (dns_packet_validate_reply(p) > 0) {
                 log_debug("Got reply packet for id %u", DNS_PACKET_ID(p));
 
-                t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
-                if (!t)
-                        return 0;
-
-                dns_transaction_process_reply(t, p);
-
-        } else if (dns_packet_validate_query(p) > 0) {
-                Link *l;
+                dns_scope_check_conflicts(scope, p);
 
-                l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
-                if (l) {
-                        DnsScope *scope = NULL;
+                t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
+                if (t)
+                        dns_transaction_process_reply(t, p);
 
-                        if (p->family == AF_INET)
-                                scope = l->llmnr_ipv4_scope;
-                        else if (p->family == AF_INET6)
-                                scope = l->llmnr_ipv6_scope;
+        } else if (dns_packet_validate_query(p) > 0)  {
+                log_debug("Got query packet for id %u", DNS_PACKET_ID(p));
 
-                        if (scope)
-                                dns_scope_process_query(scope, NULL, p);
-                }
+                dns_scope_process_query(scope, NULL, p);
         } else
-                log_debug("Invalid LLMNR packet.");
+                log_debug("Invalid LLMNR UDP packet.");
 
         return 0;
 }
@@ -1409,29 +1410,26 @@ fail:
 }
 
 static int on_llmnr_stream_packet(DnsStream *s) {
-        assert(s);
+        DnsScope *scope;
 
-        if (dns_packet_validate_query(s->read_packet) > 0) {
-                Link *l;
+        assert(s);
 
-                l = hashmap_get(s->manager->links, INT_TO_PTR(s->read_packet->ifindex));
-                if (l) {
-                        DnsScope *scope = NULL;
+        scope = manager_find_scope(s->manager, s->read_packet);
+        if (!scope) {
+                log_warning("Got LLMNR TCP packet on unknown scope. Ignroing.");
+                return 0;
+        }
 
-                        if (s->read_packet->family == AF_INET)
-                                scope = l->llmnr_ipv4_scope;
-                        else if (s->read_packet->family == AF_INET6)
-                                scope = l->llmnr_ipv6_scope;
+        if (dns_packet_validate_query(s->read_packet) > 0) {
+                log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet));
 
-                        if (scope) {
-                                dns_scope_process_query(scope, s, s->read_packet);
+                dns_scope_process_query(scope, s, s->read_packet);
 
-                                /* If no reply packet was set, we free the stream */
-                                if (s->write_packet)
-                                        return 0;
-                        }
-                }
-        }
+                /* If no reply packet was set, we free the stream */
+                if (s->write_packet)
+                        return 0;
+        } else
+                log_debug("Invalid LLMNR TCP packet.");
 
         dns_stream_free(s);
         return 0;
@@ -1648,7 +1646,7 @@ void manager_refresh_rrs(Manager *m) {
 
 int manager_next_hostname(Manager *m) {
         const char *p;
-        uint64_t u;
+        uint64_t u, a;
         char *h;
 
         assert(m);
@@ -1666,7 +1664,15 @@ int manager_next_hostname(Manager *m) {
         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
                 u = 1;
 
-        u++;
+        /* Add a random number to the old value. This way we can avoid
+         * that two hosts pick the same hostname, win on IPv4 and lose
+         * on IPv6 (or vice versa), and pick the same hostname
+         * replacement hostname, ad infinitum. We still want the
+         * numbers to go up monotonically, hence we just add a random
+         * value 1..10 */
+
+        random_bytes(&a, sizeof(a));
+        u += 1 + a % 10;
 
         if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->hostname), m->hostname, u) < 0)
                 return -ENOMEM;
@@ -1698,13 +1704,42 @@ LinkAddress* manager_find_link_address(Manager *m, int family, const union in_ad
         return NULL;
 }
 
-int manager_our_packet(Manager *m, DnsPacket *p) {
+bool manager_our_packet(Manager *m, DnsPacket *p) {
         assert(m);
         assert(p);
 
         return !!manager_find_link_address(m, p->family, &p->sender);
 }
 
+DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
+        Link *l;
+
+        assert(m);
+        assert(p);
+
+        l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
+        if (!l)
+                return NULL;
+
+        if (p->protocol == DNS_PROTOCOL_LLMNR) {
+                if (p->family == AF_INET)
+                        return l->llmnr_ipv4_scope;
+                else if (p->family == AF_INET6)
+                        return l->llmnr_ipv6_scope;
+        }
+
+        return NULL;
+}
+
+void manager_verify_all(Manager *m) {
+        DnsScope *s;
+
+        assert(m);
+
+        LIST_FOREACH(scopes, s, m->dns_scopes)
+                dns_zone_verify_all(&s->zone);
+}
+
 static const char* const support_table[_SUPPORT_MAX] = {
         [SUPPORT_NO] = "no",
         [SUPPORT_YES] = "yes",