fix: dhcp client host name resend

Signed-off-by: Ejub Sabic <ejub1946@outlook.com>

Author: saba8814

src/confd/src/dhcp-client.c

@@ -180,6 +180,20 @@ int dhcp_client_change(sr_session_ctx_t *session, struct lyd_node *config, struc
 	ifaces  = lydx_get_descendant(config, "interfaces", "interface", NULL);
 	difaces = lydx_get_descendant(diff, "interfaces", "interface", NULL);
 
+	if (diff && lydx_get_xpathf(diff, "/ietf-system:system/hostname")) {
+		LYX_LIST_FOR_EACH(ifaces, iface, "interface") {
+			const char *ifname = lydx_get_cattr(iface, "name");
+
+			ipv4 = lydx_get_descendant(lyd_child(iface), "ipv4", NULL);
+			if (!ipv4)
+				continue;
+
+			dhcp = lydx_get_descendant(lyd_child(ipv4), "dhcp", NULL);
+			if (dhcp)
+				add(ifname, dhcp);
+		}
+	}
+
 	/* find the modified interfaces */
 	LYX_LIST_FOR_EACH(difaces, diface, "interface") {
 		const char *ifname = lydx_get_cattr(diface, "name");

test/case/dhcp/client_hostname_resend/test.py

@@ -1,29 +1,21 @@
 #!/usr/bin/env python3
 """DHCP Hostname Resend
 
-Verify that updating the system hostname regenerates the DHCP client
-Finit service file so subsequent DHCP requests advertise the current
-hostname (option 12, RFC 2132).
+Verify that updating the system hostname restarts the DHCP client so
+subsequent DHCP requests advertise the current hostname (option 12,
+RFC 2132).
 
 Regression test for a bug where the DHCP client callback only reacts
 on diffs in infix-dhcp-client, so a standalone change of
-ietf-system:system/hostname leaves the previously written
-/etc/finit.d/available/dhcp-client-<iface>.conf untouched and the
-running udhcpc keeps announcing the old name.
+ietf-system:system/hostname leaves the running udhcpc untouched with
+the old '-x hostname:' argument from when it was first started.
 
 """
 
 import infamy
 from infamy.util import until
 
 
-def finit_conf(ssh, ifname):
-    """Return the contents of the generated DHCP client Finit service file."""
-    path = f"/etc/finit.d/available/dhcp-client-{ifname}.conf"
-    cmd = ssh.runsh(f"cat {path} 2>/dev/null")
-    return cmd.stdout
-
-
 def udhcpc_cmdline(ssh, ifname):
     """Return the NUL-separated argv of the running udhcpc for ifname."""
     pidfile = f"/run/dhcp-client-{ifname}.pid"