1 files changed, 20 insertions, 96 deletions

diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index 164d08907d6f..d14e0a4aa9af 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -120,29 +120,24 @@ static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
  * @buf: buffer containing message
  * @bearer: bearer that message arrived on
  */
-void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
+void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
 		   struct tipc_bearer *bearer)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct tipc_node *node;
 	struct tipc_media_addr maddr;
-	struct sk_buff *rbuf;
-	struct tipc_msg *msg = buf_msg(buf);
-	u32 ddom = msg_dest_domain(msg);
-	u32 onode = msg_prevnode(msg);
-	u32 net_id = msg_bc_netid(msg);
-	u32 mtyp = msg_type(msg);
-	u32 signature = msg_node_sig(msg);
-	u16 caps = msg_node_capabilities(msg);
-	bool addr_match = false;
-	bool sign_match = false;
-	bool link_up = false;
-	bool accept_addr = false;
-	bool accept_sign = false;
+	struct sk_buff *rskb;
+	struct tipc_msg *hdr = buf_msg(skb);
+	u32 ddom = msg_dest_domain(hdr);
+	u32 onode = msg_prevnode(hdr);
+	u32 net_id = msg_bc_netid(hdr);
+	u32 mtyp = msg_type(hdr);
+	u32 signature = msg_node_sig(hdr);
+	u16 caps = msg_node_capabilities(hdr);
 	bool respond = false;
+	bool dupl_addr = false;
 
-	bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg));
-	kfree_skb(buf);
+	bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr));
+	kfree_skb(skb);
 
 	/* Ensure message from node is valid and communication is permitted */
 	if (net_id != tn->net_id)
@@ -164,91 +159,20 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
 	if (!tipc_in_scope(bearer->domain, onode))
 		return;
 
-	node = tipc_node_create(net, onode);
-	if (!node)
-		return;
-	tipc_node_lock(node);
-	node->capabilities = caps;
-
-	/* Prepare to validate requesting node's signature and media address */
-	sign_match = (signature == node->signature);
-	tipc_node_check_dest(node, bearer, &link_up, &addr_match, &maddr);
-
-	/* These three flags give us eight permutations: */
-
-	if (sign_match && addr_match && link_up) {
-		/* All is fine. Do nothing. */
-	} else if (sign_match && addr_match && !link_up) {
-		/* Respond. The link will come up in due time */
-		respond = true;
-	} else if (sign_match && !addr_match && link_up) {
-		/* Peer has changed i/f address without rebooting.
-		 * If so, the link will reset soon, and the next
-		 * discovery will be accepted. So we can ignore it.
-		 * It may also be an cloned or malicious peer having
-		 * chosen the same node address and signature as an
-		 * existing one.
-		 * Ignore requests until the link goes down, if ever.
-		 */
+	tipc_node_check_dest(net, onode, bearer, caps, signature,
+			     &maddr, &respond, &dupl_addr);
+	if (dupl_addr)
 		disc_dupl_alert(bearer, onode, &maddr);
-	} else if (sign_match && !addr_match && !link_up) {
-		/* Peer link has changed i/f address without rebooting.
-		 * It may also be a cloned or malicious peer; we can't
-		 * distinguish between the two.
-		 * The signature is correct, so we must accept.
-		 */
-		accept_addr = true;
-		respond = true;
-	} else if (!sign_match && addr_match && link_up) {
-		/* Peer node rebooted. Two possibilities:
-		 *  - Delayed re-discovery; this link endpoint has already
-		 *    reset and re-established contact with the peer, before
-		 *    receiving a discovery message from that node.
-		 *    (The peer happened to receive one from this node first).
-		 *  - The peer came back so fast that our side has not
-		 *    discovered it yet. Probing from this side will soon
-		 *    reset the link, since there can be no working link
-		 *    endpoint at the peer end, and the link will re-establish.
-		 *  Accept the signature, since it comes from a known peer.
-		 */
-		accept_sign = true;
-	} else if (!sign_match && addr_match && !link_up) {
-		/*  The peer node has rebooted.
-		 *  Accept signature, since it is a known peer.
-		 */
-		accept_sign = true;
-		respond = true;
-	} else if (!sign_match && !addr_match && link_up) {
-		/* Peer rebooted with new address, or a new/duplicate peer.
-		 * Ignore until the link goes down, if ever.
-		 */
-		disc_dupl_alert(bearer, onode, &maddr);
-	} else if (!sign_match && !addr_match && !link_up) {
-		/* Peer rebooted with new address, or it is a new peer.
-		 * Accept signature and address.
-		*/
-		accept_sign = true;
-		accept_addr = true;
-		respond = true;
-	}
-
-	if (accept_sign)
-		node->signature = signature;
-
-	if (accept_addr && !tipc_node_update_dest(node, bearer, &maddr))
-		respond = false;
 
 	/* Send response, if necessary */
 	if (respond && (mtyp == DSC_REQ_MSG)) {
-		rbuf = tipc_buf_acquire(MAX_H_SIZE);
-		if (rbuf) {
-			tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer);
-			tipc_bearer_send(net, bearer->identity, rbuf, &maddr);
-			kfree_skb(rbuf);
+		rskb = tipc_buf_acquire(MAX_H_SIZE);
+		if (rskb) {
+			tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer);
+			tipc_bearer_send(net, bearer->identity, rskb, &maddr);
+			kfree_skb(rskb);
 		}
 	}
-	tipc_node_unlock(node);
-	tipc_node_put(node);
 }
 
 /**