bridge: export multicast database via netlink
V5: fix two bugs pointed out by Thomas
remove seq check for now, mark it as TODO
V4: remove some useless #include
some coding style fix
V3: drop debugging printk's
update selinux perm table as well
V2: drop patch 1/2, export ifindex directly
Redesign netlink attributes
Improve netlink seq check
Handle IPv6 addr as well
This patch exports bridge multicast database via netlink
message type RTM_GETMDB. Similar to fdb, but currently bridge-specific.
We may need to support modify multicast database too (RTM_{ADD,DEL}MDB).
(Thanks to Thomas for patient reviews)
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
new file mode 100644
index 0000000..edc0d73
--- /dev/null
+++ b/net/bridge/br_mdb.c
@@ -0,0 +1,163 @@
+#include <linux/err.h>
+#include <linux/igmp.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <linux/skbuff.h>
+#include <net/ip.h>
+#include <net/netlink.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#endif
+
+#include "br_private.h"
+
+static int br_rports_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
+ struct net_device *dev)
+{
+ struct net_bridge *br = netdev_priv(dev);
+ struct net_bridge_port *p;
+ struct hlist_node *n;
+ struct nlattr *nest;
+
+ if (!br->multicast_router || hlist_empty(&br->router_list))
+ return 0;
+
+ nest = nla_nest_start(skb, MDBA_ROUTER);
+ if (nest == NULL)
+ return -EMSGSIZE;
+
+ hlist_for_each_entry_rcu(p, n, &br->router_list, rlist) {
+ if (p && nla_put_u32(skb, MDBA_ROUTER_PORT, p->dev->ifindex))
+ goto fail;
+ }
+
+ nla_nest_end(skb, nest);
+ return 0;
+fail:
+ nla_nest_cancel(skb, nest);
+ return -EMSGSIZE;
+}
+
+static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
+ struct net_device *dev)
+{
+ struct net_bridge *br = netdev_priv(dev);
+ struct net_bridge_mdb_htable *mdb;
+ struct nlattr *nest, *nest2;
+ int i, err = 0;
+ int idx = 0, s_idx = cb->args[1];
+
+ if (br->multicast_disabled)
+ return 0;
+
+ mdb = rcu_dereference(br->mdb);
+ if (!mdb)
+ return 0;
+
+ nest = nla_nest_start(skb, MDBA_MDB);
+ if (nest == NULL)
+ return -EMSGSIZE;
+
+ for (i = 0; i < mdb->max; i++) {
+ struct hlist_node *h;
+ struct net_bridge_mdb_entry *mp;
+ struct net_bridge_port_group *p, **pp;
+ struct net_bridge_port *port;
+
+ hlist_for_each_entry_rcu(mp, h, &mdb->mhash[i], hlist[mdb->ver]) {
+ if (idx < s_idx)
+ goto skip;
+
+ nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
+ if (nest2 == NULL) {
+ err = -EMSGSIZE;
+ goto out;
+ }
+
+ for (pp = &mp->ports;
+ (p = rcu_dereference(*pp)) != NULL;
+ pp = &p->next) {
+ port = p->port;
+ if (port) {
+ struct br_mdb_entry e;
+ e.ifindex = port->dev->ifindex;
+ e.addr.u.ip4 = p->addr.u.ip4;
+#if IS_ENABLED(CONFIG_IPV6)
+ e.addr.u.ip6 = p->addr.u.ip6;
+#endif
+ e.addr.proto = p->addr.proto;
+ if (nla_put(skb, MDBA_MDB_ENTRY_INFO, sizeof(e), &e)) {
+ nla_nest_cancel(skb, nest2);
+ err = -EMSGSIZE;
+ goto out;
+ }
+ }
+ }
+ nla_nest_end(skb, nest2);
+ skip:
+ idx++;
+ }
+ }
+
+out:
+ cb->args[1] = idx;
+ nla_nest_end(skb, nest);
+ return err;
+}
+
+static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct net_device *dev;
+ struct net *net = sock_net(skb->sk);
+ struct nlmsghdr *nlh = NULL;
+ int idx = 0, s_idx;
+
+ s_idx = cb->args[0];
+
+ rcu_read_lock();
+
+ /* TODO: in case of rehashing, we need to check
+ * consistency for dumping.
+ */
+ cb->seq = net->dev_base_seq;
+
+ for_each_netdev_rcu(net, dev) {
+ if (dev->priv_flags & IFF_EBRIDGE) {
+ struct br_port_msg *bpm;
+
+ if (idx < s_idx)
+ goto skip;
+
+ nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, RTM_GETMDB,
+ sizeof(*bpm), NLM_F_MULTI);
+ if (nlh == NULL)
+ break;
+
+ bpm = nlmsg_data(nlh);
+ bpm->ifindex = dev->ifindex;
+ if (br_mdb_fill_info(skb, cb, dev) < 0)
+ goto out;
+ if (br_rports_fill_info(skb, cb, dev) < 0)
+ goto out;
+
+ cb->args[1] = 0;
+ nlmsg_end(skb, nlh);
+ skip:
+ idx++;
+ }
+ }
+
+out:
+ if (nlh)
+ nlmsg_end(skb, nlh);
+ rcu_read_unlock();
+ cb->args[0] = idx;
+ return skb->len;
+}
+
+void br_mdb_init(void)
+{
+ rtnl_register(PF_BRIDGE, RTM_GETMDB, NULL, br_mdb_dump, NULL);
+}