tipc: some cleanups in the file discover.c

To facilitate the coming changes in the neighbor discovery functionality
we make some renaming and refactoring of that code. The functional changes
in this commit are trivial, e.g., that we move the message sending call in
tipc_disc_timeout() outside the spinlock protected region.

Acked-by: Ying Xue <[e-mail]>
Signed-off-by: Jon Maloy <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/tipc/bearer.c

···
 	rcu_read_lock();
 	b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
 	if (b)
-		tipc_disc_add_dest(b->link_req);
+		tipc_disc_add_dest(b->disc);
 	rcu_read_unlock();
 }
 
···
 	rcu_read_lock();
 	b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
 	if (b)
-		tipc_disc_remove_dest(b->link_req);
+		tipc_disc_remove_dest(b->disc);
 	rcu_read_unlock();
 }
 
···
 	tipc_node_delete_links(net, bearer_id);
 	b->media->disable_media(b);
 	RCU_INIT_POINTER(b->media_ptr, NULL);
-	if (b->link_req)
-		tipc_disc_delete(b->link_req);
+	if (b->disc)
+		tipc_disc_delete(b->disc);
 	RCU_INIT_POINTER(tn->bearer_list[bearer_id], NULL);
 	kfree_rcu(b, rcu);
 	tipc_mon_delete(net, bearer_id);

net/tipc/bearer.h

···
 	u32 tolerance;
 	u32 domain;
 	u32 identity;
-	struct tipc_link_req *link_req;
+	struct tipc_discoverer *disc;
 	char net_plane;
 	unsigned long up;
 };

net/tipc/discover.c

···
 #include "discover.h"
 
 /* min delay during bearer start up */
-#define TIPC_LINK_REQ_INIT	msecs_to_jiffies(125)
+#define TIPC_DISC_INIT	msecs_to_jiffies(125)
 /* max delay if bearer has no links */
-#define TIPC_LINK_REQ_FAST	msecs_to_jiffies(1000)
+#define TIPC_DISC_FAST	msecs_to_jiffies(1000)
 /* max delay if bearer has links */
-#define TIPC_LINK_REQ_SLOW	msecs_to_jiffies(60000)
+#define TIPC_DISC_SLOW	msecs_to_jiffies(60000)
 /* indicates no timer in use */
-#define TIPC_LINK_REQ_INACTIVE	0xffffffff
+#define TIPC_DISC_INACTIVE	0xffffffff
 
 /**
- * struct tipc_link_req - information about an ongoing link setup request
+ * struct tipc_discoverer - information about an ongoing link setup request
  * @bearer_id: identity of bearer issuing requests
  * @net: network namespace instance
  * @dest: destination address for request messages
  * @domain: network domain to which links can be established
  * @num_nodes: number of nodes currently discovered (i.e. with an active link)
  * @lock: spinlock for controlling access to requests
- * @buf: request message to be (repeatedly) sent
+ * @skb: request message to be (repeatedly) sent
  * @timer: timer governing period between requests
  * @timer_intv: current interval between requests (in ms)
  */
-struct tipc_link_req {
+struct tipc_discoverer {
 	u32 bearer_id;
 	struct tipc_media_addr dest;
 	struct net *net;
 	u32 domain;
 	int num_nodes;
 	spinlock_t lock;
-	struct sk_buff *buf;
+	struct sk_buff *skb;
 	struct timer_list timer;
 	unsigned long timer_intv;
 };
···
  * @type: message type (request or response)
  * @b: ptr to bearer issuing message
  */
-static void tipc_disc_init_msg(struct net *net, struct sk_buff *buf, u32 type,
+static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
+			       u32 mtyp, struct tipc_bearer *b)
+{
+	struct tipc_net *tn = tipc_net(net);
+	u32 dest_domain = b->domain;
+	struct tipc_msg *hdr;
+
+	hdr = buf_msg(skb);
+	tipc_msg_init(tn->own_addr, hdr, LINK_CONFIG, mtyp,
+		      MAX_H_SIZE, dest_domain);
+	msg_set_non_seq(hdr, 1);
+	msg_set_node_sig(hdr, tn->random);
+	msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
+	msg_set_dest_domain(hdr, dest_domain);
+	msg_set_bc_netid(hdr, tn->net_id);
+	b->media->addr2msg(msg_media_addr(hdr), &b->addr);
+}
+
+static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst, u32 src,
+			       struct tipc_media_addr *maddr,
 			       struct tipc_bearer *b)
 {
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct tipc_msg *msg;
-	u32 dest_domain = b->domain;
+	struct sk_buff *skb;
 
-	msg = buf_msg(buf);
-	tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type,
-		      MAX_H_SIZE, dest_domain);
-	msg_set_non_seq(msg, 1);
-	msg_set_node_sig(msg, tn->random);
-	msg_set_node_capabilities(msg, TIPC_NODE_CAPABILITIES);
-	msg_set_dest_domain(msg, dest_domain);
-	msg_set_bc_netid(msg, tn->net_id);
-	b->media->addr2msg(msg_media_addr(msg), &b->addr);
+	skb = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
+	if (!skb)
+		return;
+	tipc_disc_init_msg(net, skb, mtyp, b);
+	tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
 }
 
 /**
···
 
 /**
  * tipc_disc_rcv - handle incoming discovery message (request or response)
- * @net: the applicable net namespace
- * @buf: buffer containing message
- * @bearer: bearer that message arrived on
+ * @net: applicable net namespace
+ * @skb: buffer containing message
+ * @b: bearer that message arrived on
  */
 void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
-		   struct tipc_bearer *bearer)
+		   struct tipc_bearer *b)
 {
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct tipc_media_addr maddr;
-	struct sk_buff *rskb;
+	struct tipc_net *tn = tipc_net(net);
 	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;
+	u32 signature = msg_node_sig(hdr);
+	u32 dst = msg_dest_domain(hdr);
+	u32 net_id = msg_bc_netid(hdr);
+	u32 self = tipc_own_addr(net);
+	struct tipc_media_addr maddr;
+	u32 src = msg_prevnode(hdr);
+	u32 mtyp = msg_type(hdr);
 	bool dupl_addr = false;
+	bool respond = false;
 	int err;
 
-	err = bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr));
+	err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
 	kfree_skb(skb);
-	if (err)
+	if (err || maddr.broadcast) {
+		pr_warn_ratelimited("Rcv corrupt discovery message\n");
 		return;
-
-	/* Ensure message from node is valid and communication is permitted */
+	}
+	/* Ignore discovery messages from own node */
+	if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
+		return;
 	if (net_id != tn->net_id)
 		return;
-	if (maddr.broadcast)
+	if (!tipc_addr_domain_valid(dst))
 		return;
-	if (!tipc_addr_domain_valid(ddom))
+	if (!tipc_addr_node_valid(src))
 		return;
-	if (!tipc_addr_node_valid(onode))
-		return;
-
-	if (in_own_node(net, onode)) {
-		if (memcmp(&maddr, &bearer->addr, sizeof(maddr)))
-			disc_dupl_alert(bearer, tn->own_addr, &maddr);
+	if (in_own_node(net, src)) {
+		disc_dupl_alert(b, self, &maddr);
 		return;
 	}
-	if (!tipc_in_scope(ddom, tn->own_addr))
+	if (!tipc_in_scope(dst, self))
 		return;
-	if (!tipc_in_scope(bearer->domain, onode))
+	if (!tipc_in_scope(b->domain, src))
 		return;
-
-	tipc_node_check_dest(net, onode, bearer, caps, signature,
+	tipc_node_check_dest(net, src, b, caps, signature,
 			     &maddr, &respond, &dupl_addr);
 	if (dupl_addr)
-		disc_dupl_alert(bearer, onode, &maddr);
+		disc_dupl_alert(b, src, &maddr);
+	if (!respond)
+		return;
+	if (mtyp != DSC_REQ_MSG)
+		return;
+	tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, &maddr, b);
+}
 
-	/* Send response, if necessary */
-	if (respond && (mtyp == DSC_REQ_MSG)) {
-		rskb = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
-		if (!rskb)
-			return;
-		tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer);
-		tipc_bearer_xmit_skb(net, bearer->identity, rskb, &maddr);
+/* tipc_disc_add_dest - increment set of discovered nodes
+ */
+void tipc_disc_add_dest(struct tipc_discoverer *d)
+{
+	spin_lock_bh(&d->lock);
+	d->num_nodes++;
+	spin_unlock_bh(&d->lock);
+}
+
+/* tipc_disc_remove_dest - decrement set of discovered nodes
+ */
+void tipc_disc_remove_dest(struct tipc_discoverer *d)
+{
+	int intv, num;
+
+	spin_lock_bh(&d->lock);
+	d->num_nodes--;
+	num = d->num_nodes;
+	intv = d->timer_intv;
+	if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST))  {
+		d->timer_intv = TIPC_DISC_INIT;
+		mod_timer(&d->timer, jiffies + d->timer_intv);
 	}
+	spin_unlock_bh(&d->lock);
 }
 
-/**
- * disc_update - update frequency of periodic link setup requests
- * @req: ptr to link request structure
- *
- * Reinitiates discovery process if discovery object has no associated nodes
- * and is either not currently searching or is searching at a slow rate
- */
-static void disc_update(struct tipc_link_req *req)
-{
-	if (!req->num_nodes) {
-		if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
-		    (req->timer_intv > TIPC_LINK_REQ_FAST)) {
-			req->timer_intv = TIPC_LINK_REQ_INIT;
-			mod_timer(&req->timer, jiffies + req->timer_intv);
-		}
-	}
-}
-
-/**
- * tipc_disc_add_dest - increment set of discovered nodes
- * @req: ptr to link request structure
- */
-void tipc_disc_add_dest(struct tipc_link_req *req)
-{
-	spin_lock_bh(&req->lock);
-	req->num_nodes++;
-	spin_unlock_bh(&req->lock);
-}
-
-/**
- * tipc_disc_remove_dest - decrement set of discovered nodes
- * @req: ptr to link request structure
- */
-void tipc_disc_remove_dest(struct tipc_link_req *req)
-{
-	spin_lock_bh(&req->lock);
-	req->num_nodes--;
-	disc_update(req);
-	spin_unlock_bh(&req->lock);
-}
-
-/**
- * disc_timeout - send a periodic link setup request
- * @data: ptr to link request structure
- *
+/* tipc_disc_timeout - send a periodic link setup request
  * Called whenever a link setup request timer associated with a bearer expires.
+ * - Keep doubling time between sent request until limit is reached;
+ * - Hold at fast polling rate if we don't have any associated nodes
+ * - Otherwise hold at slow polling rate
  */
-static void disc_timeout(struct timer_list *t)
+static void tipc_disc_timeout(struct timer_list *t)
 {
-	struct tipc_link_req *req = from_timer(req, t, timer);
-	struct sk_buff *skb;
-	int max_delay;
+	struct tipc_discoverer *d = from_timer(d, t, timer);
+	struct tipc_media_addr maddr;
+	struct sk_buff *skb = NULL;
+	struct net *net;
+	u32 bearer_id;
 
-	spin_lock_bh(&req->lock);
+	spin_lock_bh(&d->lock);
 
 	/* Stop searching if only desired node has been found */
-	if (tipc_node(req->domain) && req->num_nodes) {
-		req->timer_intv = TIPC_LINK_REQ_INACTIVE;
+	if (tipc_node(d->domain) && d->num_nodes) {
+		d->timer_intv = TIPC_DISC_INACTIVE;
 		goto exit;
 	}
-
-	/*
-	 * Send discovery message, then update discovery timer
-	 *
-	 * Keep doubling time between requests until limit is reached;
-	 * hold at fast polling rate if don't have any associated nodes,
-	 * otherwise hold at slow polling rate
-	 */
-	skb = skb_clone(req->buf, GFP_ATOMIC);
-	if (skb)
-		tipc_bearer_xmit_skb(req->net, req->bearer_id, skb, &req->dest);
-	req->timer_intv *= 2;
-	if (req->num_nodes)
-		max_delay = TIPC_LINK_REQ_SLOW;
-	else
-		max_delay = TIPC_LINK_REQ_FAST;
-	if (req->timer_intv > max_delay)
-		req->timer_intv = max_delay;
-
-	mod_timer(&req->timer, jiffies + req->timer_intv);
+	/* Adjust timeout interval according to discovery phase */
+	d->timer_intv *= 2;
+	if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
+		d->timer_intv = TIPC_DISC_SLOW;
+	else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
+		d->timer_intv = TIPC_DISC_FAST;
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	memcpy(&maddr, &d->dest, sizeof(maddr));
+	skb = skb_clone(d->skb, GFP_ATOMIC);
+	net = d->net;
+	bearer_id = d->bearer_id;
 exit:
-	spin_unlock_bh(&req->lock);
+	spin_unlock_bh(&d->lock);
+	if (skb)
+		tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
 }
 
 /**
···
 int tipc_disc_create(struct net *net, struct tipc_bearer *b,
 		     struct tipc_media_addr *dest, struct sk_buff **skb)
 {
-	struct tipc_link_req *req;
+	struct tipc_discoverer *d;
 
-	req = kmalloc(sizeof(*req), GFP_ATOMIC);
-	if (!req)
+	d = kmalloc(sizeof(*d), GFP_ATOMIC);
+	if (!d)
 		return -ENOMEM;
-	req->buf = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
-	if (!req->buf) {
-		kfree(req);
+	d->skb = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
+	if (!d->skb) {
+		kfree(d);
 		return -ENOMEM;
 	}
 
-	tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
-	memcpy(&req->dest, dest, sizeof(*dest));
-	req->net = net;
-	req->bearer_id = b->identity;
-	req->domain = b->domain;
-	req->num_nodes = 0;
-	req->timer_intv = TIPC_LINK_REQ_INIT;
-	spin_lock_init(&req->lock);
-	timer_setup(&req->timer, disc_timeout, 0);
-	mod_timer(&req->timer, jiffies + req->timer_intv);
-	b->link_req = req;
-	*skb = skb_clone(req->buf, GFP_ATOMIC);
+	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
+	memcpy(&d->dest, dest, sizeof(*dest));
+	d->net = net;
+	d->bearer_id = b->identity;
+	d->domain = b->domain;
+	d->num_nodes = 0;
+	d->timer_intv = TIPC_DISC_INIT;
+	spin_lock_init(&d->lock);
+	timer_setup(&d->timer, tipc_disc_timeout, 0);
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	b->disc = d;
+	*skb = skb_clone(d->skb, GFP_ATOMIC);
 	return 0;
 }
 
 /**
  * tipc_disc_delete - destroy object sending periodic link setup requests
- * @req: ptr to link request structure
+ * @d: ptr to link duest structure
  */
-void tipc_disc_delete(struct tipc_link_req *req)
+void tipc_disc_delete(struct tipc_discoverer *d)
 {
-	del_timer_sync(&req->timer);
-	kfree_skb(req->buf);
-	kfree(req);
+	del_timer_sync(&d->timer);
+	kfree_skb(d->skb);
+	kfree(d);
 }
 
 /**
···
  */
 void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
 {
-	struct tipc_link_req *req = b->link_req;
+	struct tipc_discoverer *d = b->disc;
+	struct tipc_media_addr maddr;
 	struct sk_buff *skb;
 
-	spin_lock_bh(&req->lock);
-	tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
-	req->net = net;
-	req->bearer_id = b->identity;
-	req->domain = b->domain;
-	req->num_nodes = 0;
-	req->timer_intv = TIPC_LINK_REQ_INIT;
-	mod_timer(&req->timer, jiffies + req->timer_intv);
-	skb = skb_clone(req->buf, GFP_ATOMIC);
+	spin_lock_bh(&d->lock);
+	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
+	d->net = net;
+	d->bearer_id = b->identity;
+	d->domain = b->domain;
+	d->num_nodes = 0;
+	d->timer_intv = TIPC_DISC_INIT;
+	memcpy(&maddr, &d->dest, sizeof(maddr));
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	skb = skb_clone(d->skb, GFP_ATOMIC);
+	spin_unlock_bh(&d->lock);
 	if (skb)
-		tipc_bearer_xmit_skb(net, req->bearer_id, skb, &req->dest);
-	spin_unlock_bh(&req->lock);
+		tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
 }

net/tipc/discover.h

···
 #ifndef _TIPC_DISCOVER_H
 #define _TIPC_DISCOVER_H
 
-struct tipc_link_req;
+struct tipc_discoverer;
 
 int tipc_disc_create(struct net *net, struct tipc_bearer *b_ptr,
 		     struct tipc_media_addr *dest, struct sk_buff **skb);
-void tipc_disc_delete(struct tipc_link_req *req);
+void tipc_disc_delete(struct tipc_discoverer *req);
 void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr);
-void tipc_disc_add_dest(struct tipc_link_req *req);
-void tipc_disc_remove_dest(struct tipc_link_req *req);
+void tipc_disc_add_dest(struct tipc_discoverer *req);
+void tipc_disc_remove_dest(struct tipc_discoverer *req);
 void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
 		   struct tipc_bearer *b_ptr);