platform: Add change link functions to nm-platform

Since updating options of bridge is now done with netlink we need
support function for that in nm-platform.

src/libnm-platform/nm-linux-platform.c

@@ -7538,6 +7538,21 @@ out:
     return result;
 }
 
+static int
+link_change(NMPlatform *platform, NMLinkType type, int ifindex, gconstpointer extra_data)
+{
+    nm_auto_nlmsg struct nl_msg *nlmsg = NULL;
+
+    nlmsg = _nl_msg_new_link(RTM_NEWLINK, 0, ifindex, 0);
+    if (!nlmsg)
+        return -NME_UNSPEC;
+
+    if (!_nl_msg_new_link_set_linkinfo(nlmsg, type, extra_data))
+        return -NME_UNSPEC;
+
+    return do_change_link(platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL);
+}
+
 static int
 link_add(NMPlatform            *platform,
          NMLinkType             type,
@@ -9920,6 +9935,7 @@ nm_linux_platform_class_init(NMLinuxPlatformClass *klass)
     platform_class->sysctl_get       = sysctl_get;
 
     platform_class->link_add    = link_add;
+    platform_class->link_change = link_change;
     platform_class->link_delete = link_delete;
 
     platform_class->link_refresh = link_refresh;

src/libnm-platform/nm-platform.c

@@ -1304,6 +1304,45 @@ nm_platform_link_add(NMPlatform            *self,
         ->link_add(self, type, name, parent, address, address_len, mtu, extra_data, out_link);
 }
 
+int
+nm_platform_link_change(NMPlatform *self, NMLinkType type, int ifindex, gconstpointer extra_data)
+{
+    char        buf[512];
+    const char *name = nm_platform_link_get_name(self, ifindex);
+
+    _CHECK_SELF(self, klass, -NME_BUG);
+
+    _LOG2D("link: changing link: "
+           "%s "    /* type */
+           "\"%s\"" /* name */
+           "%s"     /* extra_data */
+           "",
+           nm_link_type_to_string(type),
+           name,
+           ({
+               char *buf_p   = buf;
+               gsize buf_len = sizeof(buf);
+
+               buf[0] = '\0';
+
+               switch (type) {
+               case NM_LINK_TYPE_BRIDGE:
+                   nm_strbuf_append_str(&buf_p, &buf_len, ", ");
+                   nm_platform_lnk_bridge_to_string((const NMPlatformLnkBridge *) extra_data,
+                                                    buf_p,
+                                                    buf_len);
+                   break;
+               default:
+                   nm_assert(!extra_data);
+                   break;
+               }
+
+               buf;
+           }));
+
+    return klass->link_change(self, type, ifindex, extra_data);
+}
+
 /**
  * nm_platform_link_delete:
  * @self: platform instance

src/libnm-platform/nm-platform.h

@@ -1113,6 +1113,9 @@ typedef struct {
                     guint32                mtu,
                     gconstpointer          extra_data,
                     const NMPlatformLink **out_link);
+
+    int (*link_change)(NMPlatform *self, NMLinkType type, int ifindex, gconstpointer extra_data);
+
     gboolean (*link_delete)(NMPlatform *self, int ifindex);
     gboolean (*link_refresh)(NMPlatform *self, int ifindex);
     gboolean (*link_set_netns)(NMPlatform *self, int ifindex, int netns_fd);
@@ -1586,6 +1589,9 @@ int nm_platform_link_add(NMPlatform            *self,
                          gconstpointer          extra_data,
                          const NMPlatformLink **out_link);
 
+int
+nm_platform_link_change(NMPlatform *self, NMLinkType type, int ifindex, gconstpointer extra_data);
+
 static inline int
 nm_platform_link_veth_add(NMPlatform            *self,
                           const char            *name,
@@ -1621,6 +1627,12 @@ nm_platform_link_bridge_add(NMPlatform                *self,
                                 out_link);
 }
 
+static inline int
+nm_platform_link_bridge_change(NMPlatform *self, int ifindex, const NMPlatformLnkBridge *props)
+{
+    return nm_platform_link_change(self, NM_LINK_TYPE_BRIDGE, ifindex, props);
+}
+
 static inline int
 nm_platform_link_bond_add(NMPlatform *self, const char *name, const NMPlatformLink **out_link)
 {