1 files changed, 88 insertions, 1 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f2753fd58881..e8431c6c8490 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -6219,6 +6219,93 @@ out:
 	return skb->len;
 }
 
+static int rtnl_validate_mdb_entry_get(const struct nlattr *attr,
+				       struct netlink_ext_ack *extack)
+{
+	struct br_mdb_entry *entry = nla_data(attr);
+
+	if (nla_len(attr) != sizeof(struct br_mdb_entry)) {
+		NL_SET_ERR_MSG_ATTR(extack, attr, "Invalid attribute length");
+		return -EINVAL;
+	}
+
+	if (entry->ifindex) {
+		NL_SET_ERR_MSG(extack, "Entry ifindex cannot be specified");
+		return -EINVAL;
+	}
+
+	if (entry->state) {
+		NL_SET_ERR_MSG(extack, "Entry state cannot be specified");
+		return -EINVAL;
+	}
+
+	if (entry->flags) {
+		NL_SET_ERR_MSG(extack, "Entry flags cannot be specified");
+		return -EINVAL;
+	}
+
+	if (entry->vid >= VLAN_VID_MASK) {
+		NL_SET_ERR_MSG(extack, "Invalid entry VLAN id");
+		return -EINVAL;
+	}
+
+	if (entry->addr.proto != htons(ETH_P_IP) &&
+	    entry->addr.proto != htons(ETH_P_IPV6) &&
+	    entry->addr.proto != 0) {
+		NL_SET_ERR_MSG(extack, "Unknown entry protocol");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct nla_policy mdba_get_policy[MDBA_GET_ENTRY_MAX + 1] = {
+	[MDBA_GET_ENTRY] = NLA_POLICY_VALIDATE_FN(NLA_BINARY,
+						  rtnl_validate_mdb_entry_get,
+						  sizeof(struct br_mdb_entry)),
+	[MDBA_GET_ENTRY_ATTRS] = { .type = NLA_NESTED },
+};
+
+static int rtnl_mdb_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+			struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[MDBA_GET_ENTRY_MAX + 1];
+	struct net *net = sock_net(in_skb->sk);
+	struct br_port_msg *bpm;
+	struct net_device *dev;
+	int err;
+
+	err = nlmsg_parse(nlh, sizeof(struct br_port_msg), tb,
+			  MDBA_GET_ENTRY_MAX, mdba_get_policy, extack);
+	if (err)
+		return err;
+
+	bpm = nlmsg_data(nlh);
+	if (!bpm->ifindex) {
+		NL_SET_ERR_MSG(extack, "Invalid ifindex");
+		return -EINVAL;
+	}
+
+	dev = __dev_get_by_index(net, bpm->ifindex);
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "Device doesn't exist");
+		return -ENODEV;
+	}
+
+	if (NL_REQ_ATTR_CHECK(extack, NULL, tb, MDBA_GET_ENTRY)) {
+		NL_SET_ERR_MSG(extack, "Missing MDBA_GET_ENTRY attribute");
+		return -EINVAL;
+	}
+
+	if (!dev->netdev_ops->ndo_mdb_get) {
+		NL_SET_ERR_MSG(extack, "Device does not support MDB operations");
+		return -EOPNOTSUPP;
+	}
+
+	return dev->netdev_ops->ndo_mdb_get(dev, tb, NETLINK_CB(in_skb).portid,
+					    nlh->nlmsg_seq, extack);
+}
+
 static int rtnl_validate_mdb_entry(const struct nlattr *attr,
 				   struct netlink_ext_ack *extack)
 {
@@ -6595,7 +6682,7 @@ void __init rtnetlink_init(void)
 		      0);
 	rtnl_register(PF_UNSPEC, RTM_SETSTATS, rtnl_stats_set, NULL, 0);
 
-	rtnl_register(PF_BRIDGE, RTM_GETMDB, NULL, rtnl_mdb_dump, 0);
+	rtnl_register(PF_BRIDGE, RTM_GETMDB, rtnl_mdb_get, rtnl_mdb_dump, 0);
 	rtnl_register(PF_BRIDGE, RTM_NEWMDB, rtnl_mdb_add, NULL, 0);
 	rtnl_register(PF_BRIDGE, RTM_DELMDB, rtnl_mdb_del, NULL, 0);
 }