resolved: respond to local resolver requests on 127.0.0.53:53

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

diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
index 43ec92f4f0711cbe513595b7863270aaeee29f5c..7226111c075ea922cb165b524f587868edf8f997 100644 (file)
--- a/src/resolve/resolved-dns-server.c
+++ b/src/resolve/resolved-dns-server.c
@@ -1,5 +1,3 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
 /***
   This file is part of systemd.
 
@@ -23,6 +21,7 @@
 
 #include "alloc-util.h"
 #include "resolved-dns-server.h"
+#include "resolved-dns-stub.h"
 #include "resolved-resolv-conf.h"
 #include "siphash24.h"
 #include "string-table.h"
@@ -45,7 +44,8 @@ int dns_server_new(
                 DnsServerType type,
                 Link *l,
                 int family,
-                const union in_addr_union *in_addr) {
+                const union in_addr_union *in_addr,
+                int ifindex) {
 
         DnsServer *s;
 
@@ -77,6 +77,7 @@ int dns_server_new(
         s->type = type;
         s->family = family;
         s->address = *in_addr;
+        s->ifindex = ifindex;
         s->resend_timeout = DNS_TIMEOUT_MIN_USEC;
 
         switch (type) {
@@ -122,7 +123,7 @@ DnsServer* dns_server_ref(DnsServer *s)  {
                 return NULL;
 
         assert(s->n_ref > 0);
-        s->n_ref ++;
+        s->n_ref++;
 
         return s;
 }
@@ -132,7 +133,7 @@ DnsServer* dns_server_unref(DnsServer *s)  {
                 return NULL;
 
         assert(s->n_ref > 0);
-        s->n_ref --;
+        s->n_ref--;
 
         if (s->n_ref > 0)
                 return NULL;
@@ -159,6 +160,7 @@ void dns_server_unlink(DnsServer *s) {
                 assert(s->link);
                 assert(s->link->n_dns_servers > 0);
                 LIST_REMOVE(servers, s->link->dns_servers, s);
+                s->link->n_dns_servers--;
                 break;
 
         case DNS_SERVER_SYSTEM:
@@ -292,9 +294,9 @@ void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel le
 
         if (s->possible_feature_level == level) {
                 if (protocol == IPPROTO_UDP)
-                        s->n_failed_udp ++;
+                        s->n_failed_udp++;
                 else if (protocol == IPPROTO_TCP)
-                        s->n_failed_tcp ++;
+                        s->n_failed_tcp++;
         }
 
         if (s->resend_timeout > usec)
@@ -516,14 +518,27 @@ int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeature
         else
                 packet_size = server->received_udp_packet_max;
 
-        return dns_packet_append_opt(packet, packet_size, edns_do, NULL);
+        return dns_packet_append_opt(packet, packet_size, edns_do, 0, NULL);
+}
+
+int dns_server_ifindex(const DnsServer *s) {
+        assert(s);
+
+        /* The link ifindex always takes precedence */
+        if (s->link)
+                return s->link->ifindex;
+
+        if (s->ifindex > 0)
+                return s->ifindex;
+
+        return 0;
 }
 
 const char *dns_server_string(DnsServer *server) {
         assert(server);
 
         if (!server->server_string)
-                (void) in_addr_to_string(server->family, &server->address, &server->server_string);
+                (void) in_addr_ifindex_to_string(server->family, &server->address, dns_server_ifindex(server), &server->server_string);
 
         return strna(server->server_string);
 }
@@ -572,17 +587,28 @@ static void dns_server_hash_func(const void *p, struct siphash *state) {
 
         siphash24_compress(&s->family, sizeof(s->family), state);
         siphash24_compress(&s->address, FAMILY_ADDRESS_SIZE(s->family), state);
+        siphash24_compress(&s->ifindex, sizeof(s->ifindex), state);
 }
 
 static int dns_server_compare_func(const void *a, const void *b) {
         const DnsServer *x = a, *y = b;
+        int r;
 
         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));
+        r = memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
+        if (r != 0)
+                return r;
+
+        if (x->ifindex < y->ifindex)
+                return -1;
+        if (x->ifindex > y->ifindex)
+                return 1;
+
+        return 0;
 }
 
 const struct hash_ops dns_server_hash_ops = {
@@ -624,11 +650,11 @@ void dns_server_mark_all(DnsServer *first) {
         dns_server_mark_all(first->servers_next);
 }
 
-DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr) {
+DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr, int ifindex) {
         DnsServer *s;
 
         LIST_FOREACH(servers, s, first)
-                if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0)
+                if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0 && s->ifindex == ifindex)
                         return s;
 
         return NULL;
@@ -725,6 +751,19 @@ void manager_next_dns_server(Manager *m) {
                 manager_set_dns_server(m, m->dns_servers);
 }
 
+bool dns_server_address_valid(int family, const union in_addr_union *sa) {
+
+        /* Refuses the 0 IP addresses as well as 127.0.0.53 (which is our own DNS stub) */
+
+        if (in_addr_is_null(family, sa))
+                return false;
+
+        if (family == AF_INET && sa->in.s_addr == htobe32(INADDR_DNS_STUB))
+                return false;
+
+        return true;
+}
+
 static const char* const dns_server_type_table[_DNS_SERVER_TYPE_MAX] = {
         [DNS_SERVER_SYSTEM] = "system",
         [DNS_SERVER_FALLBACK] = "fallback",