1 files changed, 72 insertions, 0 deletions
diff --git a/lib/libifconfig/libifconfig_nl.c b/lib/libifconfig/libifconfig_nl.c
new file mode 100644
index 000000000000..7d9decabe26f
--- /dev/null
+++ b/lib/libifconfig/libifconfig_nl.c
@@ -0,0 +1,72 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025, Muhammad Saheed <saheed@FreeBSD.org>
+ */
+
+#include <netlink/netlink.h>
+#include <netlink/netlink_snl.h>
+#include <netlink/route/common.h>
+#include <netlink/route/interface.h>
+
+#include "libifconfig.h"
+#include "libifconfig_internal.h"
+
+static int ifconfig_modify_flags(ifconfig_handle_t *h, const char *ifname,
+    int ifi_flags, int ifi_change);
+
+static int
+ifconfig_modify_flags(ifconfig_handle_t *h, const char *ifname, int ifi_flags,
+    int ifi_change)
+{
+	int ret = 0;
+	struct snl_state ss;
+	struct snl_writer nw;
+	struct nlmsghdr *hdr;
+	struct ifinfomsg *ifi;
+	struct snl_errmsg_data e = { 0 };
+
+	if (!snl_init(&ss, NETLINK_ROUTE)) {
+		ifconfig_error(h, NETLINK, ENOTSUP);
+		return (-1);
+	}
+
+	snl_init_writer(&ss, &nw);
+	hdr = snl_create_msg_request(&nw, NL_RTM_NEWLINK);
+	ifi = snl_reserve_msg_object(&nw, struct ifinfomsg);
+	snl_add_msg_attr_string(&nw, IFLA_IFNAME, ifname);
+
+	ifi->ifi_flags = ifi_flags;
+	ifi->ifi_change = ifi_change;
+
+	hdr = snl_finalize_msg(&nw);
+	if (hdr == NULL) {
+		ifconfig_error(h, NETLINK, ENOMEM);
+		ret = -1;
+		goto out;
+	}
+
+	if (!snl_send_message(&ss, hdr)) {
+		ifconfig_error(h, NETLINK, EIO);
+		ret = -1;
+		goto out;
+	}
+
+	if (!snl_read_reply_code(&ss, hdr->nlmsg_seq, &e)) {
+		ifconfig_error(h, NETLINK, e.error);
+		ret = -1;
+		goto out;
+	}
+
+out:
+	snl_free(&ss);
+	return (ret);
+}
+
+int
+ifconfig_set_up(ifconfig_handle_t *h, const char *ifname, bool up)
+{
+	int flag = up ? IFF_UP : ~IFF_UP;
+
+	return (ifconfig_modify_flags(h, ifname, flag, IFF_UP));
+}