From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sun, 23 May 2021 07:59:40 +0000 (+0900)
Subject: udev/net: do not manage loopback interfaces
X-Git-Tag: v249-rc1~167^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=70f32a260b5ebb68c19ecadf5d69b3844896ba55;p=thirdparty%2Fsystemd.git

udev/net: do not manage loopback interfaces

There are nothing we can configure in udevd for loopback interfaces;
no ethertool configs can be applied, MAC address, interface name should
not be touched.
---

diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
index 35923b272a8..a9e263a095d 100644
--- a/src/udev/net/link-config.c
+++ b/src/udev/net/link-config.c
@@ -243,6 +243,7 @@ int link_config_get(LinkConfigContext *ctx, sd_device *device, LinkConfig **ret)
         unsigned short iftype;
         LinkConfig *link;
         const char *name;
+        unsigned flags;
         int ifindex, r;
 
         assert(ctx);
@@ -257,10 +258,14 @@ int link_config_get(LinkConfigContext *ctx, sd_device *device, LinkConfig **ret)
         if (r < 0)
                 return r;
 
-        r = rtnl_get_link_info(&ctx->rtnl, ifindex, &iftype, NULL);
+        r = rtnl_get_link_info(&ctx->rtnl, ifindex, &iftype, &flags);
         if (r < 0)
                 return r;
 
+        /* Do not configure loopback interfaces by .link files. */
+        if (flags & IFF_LOOPBACK)
+                return -ENOENT;
+
         r = ethtool_get_permanent_macaddr(&ctx->ethtool_fd, name, &permanent_mac);
         if (r < 0)
                 log_device_debug_errno(device, r, "Failed to get permanent MAC address, ignoring: %m");
diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 56a22b0a448..d6b790bc35a 100755
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -762,7 +762,7 @@ class NetworkctlTests(unittest.TestCase, Utilities):
 
         output = check_output(*networkctl_cmd, '-n', '0', 'status', 'lo', env=env)
         print(output)
-        self.assertRegex(output, r'Link File: (/usr)?/lib/systemd/network/99-default.link')
+        self.assertRegex(output, r'Link File: n/a')
         self.assertRegex(output, r'Network File: n/a')
 
     def test_delete_links(self):