tipc: move received discovery data evaluation inside node.c

The node lock is currently grabbed and and released in the function
tipc_disc_rcv() in the file discover.c. As a preparation for the next
commits, we need to move this node lock handling, along with the code
area it is covering, to node.c.

This commit introduces this change.
Tested-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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);
 }
 
 /**

net/tipc/node.c

@@ -138,7 +138,7 @@ struct tipc_node *tipc_node_find(struct net *net, u32 addr)
 	return NULL;
 }
 
-struct tipc_node *tipc_node_create(struct net *net, u32 addr)
+struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_node *n_ptr, *temp_node;
@@ -154,6 +154,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
 	}
 	n_ptr->addr = addr;
 	n_ptr->net = net;
+	n_ptr->capabilities = capabilities;
 	kref_init(&n_ptr->kref);
 	spin_lock_init(&n_ptr->lock);
 	INIT_HLIST_NODE(&n_ptr->hash);
@@ -422,38 +423,118 @@ bool tipc_node_is_up(struct tipc_node *n)
 	return n->active_links[0] != INVALID_BEARER_ID;
 }
 
-void tipc_node_check_dest(struct tipc_node *n, struct tipc_bearer *b,
-			  bool *link_up, bool *addr_match,
-			  struct tipc_media_addr *maddr)
+void tipc_node_check_dest(struct net *net, u32 onode,
+			  struct tipc_bearer *b,
+			  u16 capabilities, u32 signature,
+			  struct tipc_media_addr *maddr,
+			  bool *respond, bool *dupl_addr)
 {
-	struct tipc_link *l = n->links[b->identity].link;
-	struct tipc_media_addr *curr = &n->links[b->identity].maddr;
+	struct tipc_node *n;
+	struct tipc_link *l;
+	struct tipc_media_addr *curr_maddr;
+	struct sk_buff_head *inputq;
+	bool addr_match = false;
+	bool sign_match = false;
+	bool link_up = false;
+	bool accept_addr = false;
+
+	*dupl_addr = false;
+	*respond = false;
+
+	n = tipc_node_create(net, onode, capabilities);
+	if (!n)
+		return;
 
-	*link_up = l && tipc_link_is_up(l);
-	*addr_match = l && !memcmp(curr, maddr, sizeof(*maddr));
-}
+	tipc_node_lock(n);
 
-bool tipc_node_update_dest(struct tipc_node *n,  struct tipc_bearer *b,
-			   struct tipc_media_addr *maddr)
-{
-	struct tipc_link *l = n->links[b->identity].link;
-	struct tipc_media_addr *curr = &n->links[b->identity].maddr;
-	struct sk_buff_head *inputq = &n->links[b->identity].inputq;
+	curr_maddr = &n->links[b->identity].maddr;
+	inputq = &n->links[b->identity].inputq;
+
+	/* Prepare to validate requesting node's signature and media address */
+	l = n->links[b->identity].link;
+	link_up = l && tipc_link_is_up(l);
+	addr_match = l && !memcmp(curr_maddr, maddr, sizeof(*maddr));
+	sign_match = (signature == n->signature);
+
+	/* 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.
+		 */
+		*dupl_addr = true;
+	} 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.
+		 */
+		n->signature = signature;
+	} else if (!sign_match && addr_match && !link_up) {
+		/*  The peer node has rebooted.
+		 *  Accept signature, since it is a known peer.
+		 */
+		n->signature = signature;
+		*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.
+		 */
+		*dupl_addr = true;
+	} else if (!sign_match && !addr_match && !link_up) {
+		/* Peer rebooted with new address, or it is a new peer.
+		 * Accept signature and address.
+		 */
+		n->signature = signature;
+		accept_addr = true;
+		*respond = true;
+	}
+
+	if (!accept_addr)
+		goto exit;
 
+	/* Now create new link if not already existing */
 	if (!l) {
 		l = tipc_link_create(n, b, maddr, inputq, &n->bclink.namedq);
-		if (!l)
-			return false;
+		if (!l) {
+			*respond = false;
+			goto exit;
+		}
 		tipc_node_calculate_timer(n, l);
-		if (n->link_cnt == 1) {
+		if (n->link_cnt == 1)
 			if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
 				tipc_node_get(n);
-		}
 	}
 	memcpy(&l->media_addr, maddr, sizeof(*maddr));
-	memcpy(curr, maddr, sizeof(*maddr));
+	memcpy(curr_maddr, maddr, sizeof(*maddr));
 	tipc_node_link_down(n, b->identity);
-	return true;
+exit:
+	tipc_node_unlock(n);
+	tipc_node_put(n);
 }
 
 void tipc_node_delete_links(struct net *net, int bearer_id)

net/tipc/node.h

@@ -147,13 +147,12 @@ struct tipc_node {
 
 struct tipc_node *tipc_node_find(struct net *net, u32 addr);
 void tipc_node_put(struct tipc_node *node);
-struct tipc_node *tipc_node_create(struct net *net, u32 addr);
 void tipc_node_stop(struct net *net);
-void tipc_node_check_dest(struct tipc_node *n, struct tipc_bearer *bearer,
-			  bool *link_up, bool *addr_match,
-			  struct tipc_media_addr *maddr);
-bool tipc_node_update_dest(struct tipc_node *n, struct tipc_bearer *bearer,
-			   struct tipc_media_addr *maddr);
+void tipc_node_check_dest(struct net *net, u32 onode,
+			  struct tipc_bearer *bearer,
+			  u16 capabilities, u32 signature,
+			  struct tipc_media_addr *maddr,
+			  bool *respond, bool *dupl_addr);
 void tipc_node_delete_links(struct net *net, int bearer_id);
 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
 void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);