1 files changed, 87 insertions, 0 deletions
diff --git a/src/udev/udev-netlink.c b/src/udev/udev-netlink.c
new file mode 100644
index 0000000000..4c93934e3e
--- /dev/null
+++ b/src/udev/udev-netlink.c
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "netlink-util.h"
+#include "udev-netlink.h"
+
+void link_info_clear(LinkInfo *info) {
+        if (!info)
+                return;
+
+        info->ifname = mfree(info->ifname);
+        info->phys_port_name = mfree(info->phys_port_name);
+}
+
+int link_info_get(sd_netlink **rtnl, int ifindex, LinkInfo *ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
+        _cleanup_(link_info_clear) LinkInfo info = LINK_INFO_NULL;
+        uint16_t nlmsg_type;
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+        assert(ret);
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, &reply);
+        if (r == -EINVAL)
+                return -ENODEV; /* The device does not exist */
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_get_type(reply, &nlmsg_type);
+        if (r < 0)
+                return r;
+        if (nlmsg_type != RTM_NEWLINK)
+                return -ENXIO;
+
+        r = sd_rtnl_message_link_get_ifindex(reply, &info.ifindex);
+        if (r < 0)
+                return r;
+        if (info.ifindex != ifindex)
+                return -ENXIO;
+
+        r = sd_rtnl_message_link_get_type(reply, &info.iftype);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_hw_addr(reply, IFLA_ADDRESS, &info.hw_addr);
+        if (r < 0 && r != -ENODATA)
+                return r;
+
+        r = sd_netlink_message_read_string_strdup(reply, IFLA_IFNAME, &info.ifname);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_read_u32(reply, IFLA_LINK, &info.iflink);
+        if (r == -ENODATA)
+                info.iflink = info.ifindex;
+        else if (r < 0)
+                return r;
+
+        r = sd_netlink_message_read_string_strdup(reply, IFLA_PHYS_PORT_NAME, &info.phys_port_name);
+        if (r == -ENODATA) {
+                uint16_t max_attr;
+
+                r = sd_netlink_message_get_max_attribute(reply, &max_attr);
+                if (r < 0)
+                        return r;
+
+                info.support_phys_port_name = max_attr >= IFLA_PHYS_PORT_NAME;
+        } else if (r >= 0)
+                info.support_phys_port_name = true;
+        else
+                return r;
+
+        *ret = info;
+        info = LINK_INFO_NULL;
+        return 0;
+}