mdb: support bridge multicast database notification

The Linux kernel has a notification system via Netlink that reports the
changes in the multicast database over the RTNLGRP_MDB multicast socket.
As such notifications such as RTM_NEWMDB, RTM_GETMDB can be processed in
userspace.
libnl must support the capability of processing these messages, e.g.
RTM_GETMDB.
This commit adds a new rtnl_mdb object as well as a route/mdb cache,
in order to expose the contents of the multicast database.

3 files changed, 72 insertions, 0 deletions

diff --git a/include/netlink-private/types.h b/include/netlink-private/types.h
index 0bfaae0..5cd2b95 100644
--- a/include/netlink-private/types.h
+++ b/include/netlink-private/types.h
@@ -1346,4 +1346,22 @@ struct rtnl_vlan
 	uint32_t       v_flags;
 };
 
+struct rtnl_mdb {
+	NLHDR_COMMON
+	uint32_t ifindex;
+
+	struct nl_list_head mdb_entry_list;
+};
+
+struct rtnl_mdb_entry {
+	uint32_t  ce_mask; /* HACK to support attr macros */
+
+	uint32_t ifindex;
+	uint8_t state;
+	uint16_t vid;
+	struct nl_addr *addr;
+	uint16_t proto;
+
+	struct nl_list_head mdb_list;
+};
 #endif
diff --git a/include/netlink/cli/mdb.h b/include/netlink/cli/mdb.h
new file mode 100644
index 0000000..cd37604
--- /dev/null
+++ b/include/netlink/cli/mdb.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: LGPL-2.1-only */
+
+#ifndef __NETLINK_CLI_MDB_H_
+#define __NETLINK_CLI_MDB_H_
+
+#include <netlink/route/mdb.h>
+
+#define nl_cli_mdb_alloc_cache(sk) \
+		nl_cli_alloc_cache_flags((sk), "mdb", NL_CACHE_AF_ITER, rtnl_mdb_alloc_cache)
+
+#endif
diff --git a/include/netlink/route/mdb.h b/include/netlink/route/mdb.h
new file mode 100644
index 0000000..fc518bb
--- /dev/null
+++ b/include/netlink/route/mdb.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1-only */
+
+#ifndef NETLINK_MDB_H_
+#define NETLINK_MDB_H_
+
+#include <netlink/netlink.h>
+#include <netlink/cache.h>
+#include <netlink/route/link.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+	struct rtnl_mdb_entry;
+	struct rtnl_mdb *rtnl_mdb_alloc(void);
+	void rtnl_mdb_put(struct rtnl_mdb *mdb);
+
+	int rtnl_mdb_alloc_cache(struct nl_sock *sk, struct nl_cache **result);
+	int rtnl_mdb_alloc_cache_flags(struct nl_sock *sock,
+				       struct nl_cache **result,
+				       unsigned int flags);
+
+	int rtnl_mdb_add();
+	struct rtnl_mdb_entry *rtnl_mdb_entry_alloc(void);
+
+	uint32_t rtnl_mdb_get_ifindex(struct rtnl_mdb *mdb);
+	void rtnl_mdb_add_entry(struct rtnl_mdb *mdb,
+				struct rtnl_mdb_entry *_entry);
+
+	void rtnl_mdb_foreach_entry(struct rtnl_mdb *mdb,
+				    void (*cb)(struct rtnl_mdb_entry *, void *),
+				    void *arg);
+
+	int rtnl_mdb_entry_get_ifindex(struct rtnl_mdb_entry *mdb_entry);
+	int rtnl_mdb_entry_get_vid(struct rtnl_mdb_entry *mdb_entry);
+	int rtnl_mdb_entry_get_state(struct rtnl_mdb_entry *mdb_entry);
+	struct nl_addr *rtnl_mdb_entry_get_addr(struct rtnl_mdb_entry
+						*mdb_entry);
+	uint16_t rtnl_mdb_entry_get_proto(struct rtnl_mdb_entry *mdb_entry);
+#ifdef __cplusplus
+}
+#endif
+#endif