tipc: add node get/dump to new netlink api

Add TIPC_NL_NODE_GET to the new tipc netlink API.

This command can dump the address and node status of all nodes in the
tipc cluster.

Netlink logical layout of returned node/address data:
-> node
    -> address
    -> up flag

Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@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>

1 files changed, 96 insertions, 0 deletions

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 5781634e957d..72a75d4838b2 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -58,6 +58,12 @@ struct tipc_sock_conn {
         struct list_head list;
 };
 
+static const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
+        [TIPC_NLA_NODE_UNSPEC]          = { .type = NLA_UNSPEC },
+        [TIPC_NLA_NODE_ADDR]            = { .type = NLA_U32 },
+        [TIPC_NLA_NODE_UP]              = { .type = NLA_FLAG }
+};
+
 /*
  * A trivial power-of-two bitmask technique is used for speed, since this
  * operation is done for every incoming TIPC packet. The number of hash table
@@ -601,3 +607,93 @@ void tipc_node_unlock(struct tipc_node *node)
                 tipc_nametbl_withdraw(TIPC_LINK_STATE, addr,
                                       link_id, addr);
 }
+
+/* Caller should hold node lock for the passed node */
+int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
+{
+        void *hdr;
+        struct nlattr *attrs;
+
+        hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_v2_family,
+                          NLM_F_MULTI, TIPC_NL_NODE_GET);
+        if (!hdr)
+                return -EMSGSIZE;
+
+        attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
+        if (!attrs)
+                goto msg_full;
+
+        if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
+                goto attr_msg_full;
+        if (tipc_node_is_up(node))
+                if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
+                        goto attr_msg_full;
+
+        nla_nest_end(msg->skb, attrs);
+        genlmsg_end(msg->skb, hdr);
+
+        return 0;
+
+attr_msg_full:
+        nla_nest_cancel(msg->skb, attrs);
+msg_full:
+        genlmsg_cancel(msg->skb, hdr);
+
+        return -EMSGSIZE;
+}
+
+int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        int err;
+        int done = cb->args[0];
+        int last_addr = cb->args[1];
+        struct tipc_node *node;
+        struct tipc_nl_msg msg;
+
+        if (done)
+                return 0;
+
+        msg.skb = skb;
+        msg.portid = NETLINK_CB(cb->skb).portid;
+        msg.seq = cb->nlh->nlmsg_seq;
+
+        rcu_read_lock();
+
+        if (last_addr && !tipc_node_find(last_addr)) {
+                rcu_read_unlock();
+                /* We never set seq or call nl_dump_check_consistent() this
+                 * means that setting prev_seq here will cause the consistence
+                 * check to fail in the netlink callback handler. Resulting in
+                 * the NLMSG_DONE message having the NLM_F_DUMP_INTR flag set if
+                 * the node state changed while we released the lock.
+                 */
+                cb->prev_seq = 1;
+                return -EPIPE;
+        }
+
+        list_for_each_entry_rcu(node, &tipc_node_list, list) {
+                if (last_addr) {
+                        if (node->addr == last_addr)
+                                last_addr = 0;
+                        else
+                                continue;
+                }
+
+                tipc_node_lock(node);
+                err = __tipc_nl_add_node(&msg, node);
+                if (err) {
+                        last_addr = node->addr;
+                        tipc_node_unlock(node);
+                        goto out;
+                }
+
+                tipc_node_unlock(node);
+        }
+        done = 1;
+out:
+        cb->args[0] = done;
+        cb->args[1] = last_addr;
+        rcu_read_unlock();
+
+        return skb->len;
+}