tipc: add support for broadcast rcv stats dumping

This commit enables dumping the statistics of a broadcast-receiver link
like the traditional 'broadcast-link' one (which is for broadcast-
sender). The link dumping can be triggered via netlink (e.g. the
iproute2/tipc tool) by the link flag - 'TIPC_NLA_LINK_BROADCAST' as the
indicator.

The name of a broadcast-receiver link of a specific peer will be in the
format: 'broadcast-link:<peer-id>'.

For example:

Link <broadcast-link:1001002>
Window:50 packets
RX packets:7841 fragments:2408/440 bundles:0/0
TX packets:0 fragments:0/0 bundles:0/0
RX naks:0 defs:124 dups:0
TX naks:21 acks:0 retrans:0
Congestion link:0 Send queue max:0 avg:0

In addition, the broadcast-receiver link statistics can be reset in the
usual way via netlink by specifying that link name in command.

Note: the 'tipc_link_name_ext()' is removed because the link name can
now be retrieved simply via the 'l->name'.

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

net/tipc/bcast.c

···
 		tipc_sk_rcv(net, inputq);
 }
 
-int tipc_bclink_reset_stats(struct net *net)
+int tipc_bclink_reset_stats(struct net *net, struct tipc_link *l)
 {
-	struct tipc_link *l = tipc_bc_sndlink(net);
-
 	if (!l)
 		return -ENOPROTOOPT;
 
···
 	tn->bcbase = bb;
 	spin_lock_init(&tipc_net(net)->bclock);
 
-	if (!tipc_link_bc_create(net, 0, 0,
+	if (!tipc_link_bc_create(net, 0, 0, NULL,
 				 FB_MTU,
 				 BCLINK_WIN_DEFAULT,
 				 BCLINK_WIN_DEFAULT,

net/tipc/bcast.h

···
 int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
 			struct tipc_msg *hdr,
 			struct sk_buff_head *retrq);
-int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg);
+int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
+			struct tipc_link *bcl);
 int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[]);
-int tipc_bclink_reset_stats(struct net *net);
+int tipc_bclink_reset_stats(struct net *net, struct tipc_link *l);
 
 u32 tipc_bcast_get_broadcast_mode(struct net *net);
 u32 tipc_bcast_get_broadcast_ratio(struct net *net);

net/tipc/link.c

···
  *
  * Returns true if link was created, otherwise false
  */
-bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
+bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
 			 struct sk_buff_head *inputq,
 			 struct sk_buff_head *namedq,
···
 		return false;
 
 	l = *link;
-	strcpy(l->name, tipc_bclink_name);
+	if (peer_id) {
+		char peer_str[NODE_ID_STR_LEN] = {0,};
+
+		tipc_nodeid2string(peer_str, peer_id);
+		if (strlen(peer_str) > 16)
+			sprintf(peer_str, "%x", peer);
+		/* Broadcast receiver link name: "broadcast-link:<peer>" */
+		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
+			 peer_str);
+	} else {
+		strcpy(l->name, tipc_bclink_name);
+	}
 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
 	tipc_link_reset(l);
 	l->state = LINK_RESET;
···
 			gacks[n].ack = htons(expect - 1);
 			gacks[n].gap = htons(seqno - expect);
 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
-				char buf[TIPC_MAX_LINK_NAME];
-
 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
-						    tipc_link_name_ext(l, buf),
-						    n,
+						    l->name, n,
 						    skb_queue_len(&l->deferdq));
 				return n;
 			}
···
 			_skb->priority = TC_PRIO_CONTROL;
 			__skb_queue_tail(xmitq, _skb);
 			l->stats.retransmitted++;
+			if (!is_uc)
+				r->stats.retransmitted++;
 			*retransmitted = true;
 			/* Increase actual retrans counter & mark first time */
 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
···
 
 		/* Defer delivery if sequence gap */
 		if (unlikely(seqno != rcv_nxt)) {
-			__tipc_skb_queue_sorted(defq, seqno, skb);
+			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
+				l->stats.duplicates++;
 			rc |= tipc_link_build_nack_msg(l, xmitq);
 			break;
 		}
···
 				      int tolerance, int priority,
 				      struct sk_buff_head *xmitq)
 {
-	struct tipc_link *bcl = l->bc_rcvlink;
-	struct sk_buff *skb;
-	struct tipc_msg *hdr;
-	struct sk_buff_head *dfq = &l->deferdq;
-	bool node_up = link_is_up(bcl);
 	struct tipc_mon_state *mstate = &l->mon_state;
+	struct sk_buff_head *dfq = &l->deferdq;
+	struct tipc_link *bcl = l->bc_rcvlink;
+	struct tipc_msg *hdr;
+	struct sk_buff *skb;
+	bool node_up = link_is_up(bcl);
+	u16 glen = 0, bc_rcvgap = 0;
 	int dlen = 0;
 	void *data;
-	u16 glen = 0;
 
 	/* Don't send protocol message during reset or link failover */
 	if (tipc_link_is_blocked(l))
···
 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
 			msg_set_seqno(hdr, l->snd_nxt_state++);
 		msg_set_seq_gap(hdr, rcvgap);
-		msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
+		bc_rcvgap = link_bc_rcv_gap(bcl);
+		msg_set_bc_gap(hdr, bc_rcvgap);
 		msg_set_probe(hdr, probe);
 		msg_set_is_keepalive(hdr, probe || probe_reply);
 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
···
 		l->stats.sent_probes++;
 	if (rcvgap)
 		l->stats.sent_nacks++;
+	if (bc_rcvgap)
+		bcl->stats.sent_nacks++;
 	skb->priority = TC_PRIO_CONTROL;
 	__skb_queue_tail(xmitq, skb);
 	trace_tipc_proto_build(skb, false, l->name);
···
 	if (!l->bc_peer_is_up)
 		return rc;
 
-	l->stats.recv_nacks++;
-
 	/* Ignore if peers_snd_nxt goes beyond receive window */
 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
 		return rc;
···
 
 	if (!link_is_up(r) || !r->bc_peer_is_up)
 		return 0;
+
+	if (gap) {
+		l->stats.recv_nacks++;
+		r->stats.recv_nacks++;
+	}
 
 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
 		return 0;
···
 	return -EMSGSIZE;
 }
 
-int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
+int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
+			struct tipc_link *bcl)
 {
 	int err;
 	void *hdr;
 	struct nlattr *attrs;
 	struct nlattr *prop;
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	u32 bc_mode = tipc_bcast_get_broadcast_mode(net);
 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
-	struct tipc_link *bcl = tn->bcl;
 
 	if (!bcl)
 		return 0;
···
 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
 {
 	l->abort_limit = limit;
-}
-
-char *tipc_link_name_ext(struct tipc_link *l, char *buf)
-{
-	if (!l)
-		scnprintf(buf, TIPC_MAX_LINK_NAME, "null");
-	else if (link_is_bc_sndlink(l))
-		scnprintf(buf, TIPC_MAX_LINK_NAME, "broadcast-sender");
-	else if (link_is_bc_rcvlink(l))
-		scnprintf(buf, TIPC_MAX_LINK_NAME,
-			  "broadcast-receiver, peer %x", l->addr);
-	else
-		memcpy(buf, l->name, TIPC_MAX_LINK_NAME);
-
-	return buf;
 }
 
 /**

net/tipc/link.h

···
 		      struct sk_buff_head *inputq,
 		      struct sk_buff_head *namedq,
 		      struct tipc_link **link);
-bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
+bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
 			 struct sk_buff_head *inputq,
 			 struct sk_buff_head *namedq,
···
 u16 tipc_link_acked(struct tipc_link *l);
 u32 tipc_link_id(struct tipc_link *l);
 char *tipc_link_name(struct tipc_link *l);
-char *tipc_link_name_ext(struct tipc_link *l, char *buf);
 u32 tipc_link_state(struct tipc_link *l);
 char tipc_link_plane(struct tipc_link *l);
 int tipc_link_prio(struct tipc_link *l);

net/tipc/msg.c

···
  * @seqno: sequence number of buffer to add
  * @skb: buffer to add
  */
-void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
+bool __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 			     struct sk_buff *skb)
 {
 	struct sk_buff *_skb, *tmp;
 
 	if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
 		__skb_queue_head(list, skb);
-		return;
+		return true;
 	}
 
 	if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
 		__skb_queue_tail(list, skb);
-		return;
+		return true;
 	}
 
 	skb_queue_walk_safe(list, _skb, tmp) {
···
 		if (seqno == buf_seqno(_skb))
 			break;
 		__skb_queue_before(list, _skb, skb);
-		return;
+		return true;
 	}
 	kfree_skb(skb);
+	return false;
 }
 
 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,

net/tipc/msg.h

···
 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq);
 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
 			struct sk_buff_head *cpy);
-void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
+bool __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 			     struct sk_buff *skb);
 bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy);
 

net/tipc/netlink.c

···
 	},
 	{
 		.cmd	= TIPC_NL_LINK_GET,
-		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.validate = GENL_DONT_VALIDATE_STRICT,
 		.doit   = tipc_nl_node_get_link,
 		.dumpit	= tipc_nl_node_dump_link,
 	},

net/tipc/node.c

···
 	if (unlikely(!n->bc_entry.link)) {
 		snd_l = tipc_bc_sndlink(net);
 		if (!tipc_link_bc_create(net, tipc_own_addr(net),
-					 addr, U16_MAX,
+					 addr, peer_id, U16_MAX,
 					 tipc_link_min_win(snd_l),
 					 tipc_link_max_win(snd_l),
 					 n->capabilities,
···
 		return -ENOMEM;
 
 	if (strcmp(name, tipc_bclink_name) == 0) {
-		err = tipc_nl_add_bc_link(net, &msg);
+		err = tipc_nl_add_bc_link(net, &msg, tipc_net(net)->bcl);
 		if (err)
 			goto err_free;
 	} else {
···
 	struct tipc_node *node;
 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
 	struct net *net = sock_net(skb->sk);
+	struct tipc_net *tn = tipc_net(net);
 	struct tipc_link_entry *le;
 
 	if (!info->attrs[TIPC_NLA_LINK])
···
 
 	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
 
-	if (strcmp(link_name, tipc_bclink_name) == 0) {
-		err = tipc_bclink_reset_stats(net);
+	err = -EINVAL;
+	if (!strcmp(link_name, tipc_bclink_name)) {
+		err = tipc_bclink_reset_stats(net, tipc_bc_sndlink(net));
 		if (err)
 			return err;
 		return 0;
+	} else if (strstr(link_name, tipc_bclink_name)) {
+		rcu_read_lock();
+		list_for_each_entry_rcu(node, &tn->node_list, list) {
+			tipc_node_read_lock(node);
+			link = node->bc_entry.link;
+			if (link && !strcmp(link_name, tipc_link_name(link))) {
+				err = tipc_bclink_reset_stats(net, link);
+				tipc_node_read_unlock(node);
+				break;
+			}
+			tipc_node_read_unlock(node);
+		}
+		rcu_read_unlock();
+		return err;
 	}
 
 	node = tipc_node_find_by_name(net, link_name, &bearer_id);
···
 
 /* Caller should hold node lock  */
 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
-				    struct tipc_node *node, u32 *prev_link)
+				    struct tipc_node *node, u32 *prev_link,
+				    bool bc_link)
 {
 	u32 i;
 	int err;
···
 		if (err)
 			return err;
 	}
+
+	if (bc_link) {
+		*prev_link = i;
+		err = tipc_nl_add_bc_link(net, msg, node->bc_entry.link);
+		if (err)
+			return err;
+	}
+
 	*prev_link = 0;
 
 	return 0;
···
 int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net *net = sock_net(skb->sk);
+	struct nlattr **attrs = genl_dumpit_info(cb)->attrs;
+	struct nlattr *link[TIPC_NLA_LINK_MAX + 1];
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_node *node;
 	struct tipc_nl_msg msg;
 	u32 prev_node = cb->args[0];
 	u32 prev_link = cb->args[1];
 	int done = cb->args[2];
+	bool bc_link = cb->args[3];
 	int err;
 
 	if (done)
 		return 0;
+
+	if (!prev_node) {
+		/* Check if broadcast-receiver links dumping is needed */
+		if (attrs && attrs[TIPC_NLA_LINK]) {
+			err = nla_parse_nested_deprecated(link,
+							  TIPC_NLA_LINK_MAX,
+							  attrs[TIPC_NLA_LINK],
+							  tipc_nl_link_policy,
+							  NULL);
+			if (unlikely(err))
+				return err;
+			if (unlikely(!link[TIPC_NLA_LINK_BROADCAST]))
+				return -EINVAL;
+			bc_link = true;
+		}
+	}
 
 	msg.skb = skb;
 	msg.portid = NETLINK_CB(cb->skb).portid;
···
 						 list) {
 			tipc_node_read_lock(node);
 			err = __tipc_nl_add_node_links(net, &msg, node,
-						       &prev_link);
+						       &prev_link, bc_link);
 			tipc_node_read_unlock(node);
 			if (err)
 				goto out;
···
 			prev_node = node->addr;
 		}
 	} else {
-		err = tipc_nl_add_bc_link(net, &msg);
+		err = tipc_nl_add_bc_link(net, &msg, tn->bcl);
 		if (err)
 			goto out;
 
 		list_for_each_entry_rcu(node, &tn->node_list, list) {
 			tipc_node_read_lock(node);
 			err = __tipc_nl_add_node_links(net, &msg, node,
-						       &prev_link);
+						       &prev_link, bc_link);
 			tipc_node_read_unlock(node);
 			if (err)
 				goto out;
···
 	cb->args[0] = prev_node;
 	cb->args[1] = prev_link;
 	cb->args[2] = done;
+	cb->args[3] = bc_link;
 
 	return skb->len;
 }

net/tipc/trace.h

···
 
 	TP_fast_assign(
 		__assign_str(header, header);
-		tipc_link_name_ext(l, __entry->name);
+		memcpy(__entry->name, tipc_link_name(l), TIPC_MAX_LINK_NAME);
 		tipc_link_dump(l, dqueues, __get_str(buf));
 	),
 
···
 	),
 
 	TP_fast_assign(
-		tipc_link_name_ext(r, __entry->name);
+		memcpy(__entry->name, tipc_link_name(r), TIPC_MAX_LINK_NAME);
 		__entry->from = f;
 		__entry->to = t;
 		__entry->len = skb_queue_len(tq);