nss-myhostname: always resolve the host name "gateway" to the local default gateway

This is useful inside of containers or local networks to intrdouce a
stable name of the default gateway host (in case of containers usually
the host, in case of LANs usually local router).

1 files changed, 58 insertions, 0 deletions

diff --git a/src/libsystemd/sd-rtnl/test-local-addresses.c b/src/libsystemd/sd-rtnl/test-local-addresses.c
new file mode 100644
index 0000000000..4cf2c08312
--- /dev/null
+++ b/src/libsystemd/sd-rtnl/test-local-addresses.c
@@ -0,0 +1,58 @@
+/*-*- 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 "in-addr-util.h"
+#include "local-addresses.h"
+#include "af-list.h"
+
+static void print_local_addresses(struct local_address *a, unsigned n) {
+        unsigned i;
+
+        for (i = 0; i < n; i++) {
+                _cleanup_free_ char *b = NULL;
+
+                assert_se(in_addr_to_string(a[i].family, &a[i].address, &b) >= 0);
+                printf("%s if%i scope=%i metric=%u address=%s\n", af_to_name(a[i].family), a[i].ifindex, a[i].scope, a[i].metric, b);
+        }
+}
+
+int main(int argc, char *argv[]) {
+        struct local_address *a;
+        int n;
+
+        a = NULL;
+        n = local_addresses(NULL, 0, &a);
+        assert_se(n >= 0);
+
+        printf("Local Addresses:\n");
+        print_local_addresses(a, (unsigned) n);
+        free(a);
+
+        a = NULL;
+        n = local_gateways(NULL, 0, &a);
+        assert_se(n >= 0);
+
+        printf("Local Gateways:\n");
+        print_local_addresses(a, (unsigned) n);
+        free(a);
+
+        return 0;
+}