tipc: add peer removal functionality

Add TIPC_NL_PEER_REMOVE netlink command. This command can remove
an offline peer node from the internal data structures.

This will be supported by the tipc user space tool in iproute2.
Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/tipc_netlink.h

@@ -59,6 +59,7 @@ enum {
 	TIPC_NL_MON_SET,
 	TIPC_NL_MON_GET,
 	TIPC_NL_MON_PEER_GET,
+	TIPC_NL_PEER_REMOVE,
 
 	__TIPC_NL_CMD_MAX,
 	TIPC_NL_CMD_MAX = __TIPC_NL_CMD_MAX - 1

net/tipc/net.h

@@ -39,6 +39,8 @@
 
 #include <net/genetlink.h>
 
+extern const struct nla_policy tipc_nl_net_policy[];
+
 int tipc_net_start(struct net *net, u32 addr);
 
 void tipc_net_stop(struct net *net);

net/tipc/netlink.c

@@ -238,6 +238,11 @@ static const struct genl_ops tipc_genl_v2_ops[] = {
 		.dumpit	= tipc_nl_node_dump_monitor_peer,
 		.policy = tipc_nl_policy,
 	},
+	{
+		.cmd	= TIPC_NL_PEER_REMOVE,
+		.doit	= tipc_nl_peer_rm,
+		.policy = tipc_nl_policy,
+	}
 };
 
 int tipc_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr ***attr)

net/tipc/node.c

@@ -1553,6 +1553,69 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 	kfree_skb(skb);
 }
 
+int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
+	struct tipc_node *peer;
+	u32 addr;
+	int err;
+	int i;
+
+	/* We identify the peer by its net */
+	if (!info->attrs[TIPC_NLA_NET])
+		return -EINVAL;
+
+	err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
+			       info->attrs[TIPC_NLA_NET],
+			       tipc_nl_net_policy);
+	if (err)
+		return err;
+
+	if (!attrs[TIPC_NLA_NET_ADDR])
+		return -EINVAL;
+
+	addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
+
+	if (in_own_node(net, addr))
+		return -ENOTSUPP;
+
+	spin_lock_bh(&tn->node_list_lock);
+	peer = tipc_node_find(net, addr);
+	if (!peer) {
+		spin_unlock_bh(&tn->node_list_lock);
+		return -ENXIO;
+	}
+
+	tipc_node_write_lock(peer);
+	if (peer->state != SELF_DOWN_PEER_DOWN &&
+	    peer->state != SELF_DOWN_PEER_LEAVING) {
+		tipc_node_write_unlock(peer);
+		err = -EBUSY;
+		goto err_out;
+	}
+
+	for (i = 0; i < MAX_BEARERS; i++) {
+		struct tipc_link_entry *le = &peer->links[i];
+
+		if (le->link) {
+			kfree(le->link);
+			le->link = NULL;
+			peer->link_cnt--;
+		}
+	}
+	tipc_node_write_unlock(peer);
+	tipc_node_delete(peer);
+
+	err = 0;
+err_out:
+	tipc_node_put(peer);
+	spin_unlock_bh(&tn->node_list_lock);
+
+	return err;
+}
+
 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	int err;

net/tipc/node.h

@@ -77,6 +77,7 @@ int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb);
 int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info);
 int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info);
 int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info);
+int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info);
 
 int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info);
 int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info);