tipc: fix link statistics counter errors

In commit e4bf4f76 ("tipc: simplify packet sequence number
handling") we changed the internal representation of the packet
sequence number counters from u32 to u16, reflecting what is really
sent over the wire.

Since then some link statistics counters have been displaying incorrect
values, partially because the counters meant to be used as sequence
number snapshots are now used as direct counters, stored as u32, and
partially because some counter updates are just missing in the code.

In this commit we correct this in two ways. First, we base the
displayed packet sent/received values on direct counters instead
of as previously a calculated difference between current sequence
number and a snapshot. Second, we add the missing updates of the
counters.

This change is compatible with the current netlink API, and requires
no changes to the user space tools.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/link.c

@@ -47,8 +47,8 @@
 #include <linux/pkt_sched.h>
 
 struct tipc_stats {
-	u32 sent_info;		/* used in counting # sent packets */
-	u32 recv_info;		/* used in counting # recv'd packets */
+	u32 sent_pkts;
+	u32 recv_pkts;
 	u32 sent_states;
 	u32 recv_states;
 	u32 sent_probes;
@@ -857,7 +857,6 @@ void tipc_link_reset(struct tipc_link *l)
 	l->acked = 0;
 	l->silent_intv_cnt = 0;
 	l->rst_cnt = 0;
-	l->stats.recv_info = 0;
 	l->stale_count = 0;
 	l->bc_peer_is_up = false;
 	memset(&l->mon_state, 0, sizeof(l->mon_state));
@@ -888,6 +887,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 	struct sk_buff_head *transmq = &l->transmq;
 	struct sk_buff_head *backlogq = &l->backlogq;
 	struct sk_buff *skb, *_skb, *bskb;
+	int pkt_cnt = skb_queue_len(list);
 
 	/* Match msg importance against this and all higher backlog limits: */
 	if (!skb_queue_empty(backlogq)) {
@@ -901,6 +901,11 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 		return -EMSGSIZE;
 	}
 
+	if (pkt_cnt > 1) {
+		l->stats.sent_fragmented++;
+		l->stats.sent_fragments += pkt_cnt;
+	}
+
 	/* Prepare each packet for sending, and add to relevant queue: */
 	while (skb_queue_len(list)) {
 		skb = skb_peek(list);
@@ -920,6 +925,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 			__skb_queue_tail(xmitq, _skb);
 			TIPC_SKB_CB(skb)->ackers = l->ackers;
 			l->rcv_unacked = 0;
+			l->stats.sent_pkts++;
 			seqno++;
 			continue;
 		}
@@ -968,6 +974,7 @@ void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 		msg_set_ack(hdr, ack);
 		msg_set_bcast_ack(hdr, bc_ack);
 		l->rcv_unacked = 0;
+		l->stats.sent_pkts++;
 		seqno++;
 	}
 	l->snd_nxt = seqno;
@@ -1260,7 +1267,7 @@ int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
 
 		/* Deliver packet */
 		l->rcv_nxt++;
-		l->stats.recv_info++;
+		l->stats.recv_pkts++;
 		if (!tipc_data_input(l, skb, l->inputq))
 			rc |= tipc_link_input(l, skb, l->inputq);
 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
@@ -1800,10 +1807,6 @@ void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
 void tipc_link_reset_stats(struct tipc_link *l)
 {
 	memset(&l->stats, 0, sizeof(l->stats));
-	if (!link_is_bc_sndlink(l)) {
-		l->stats.sent_info = l->snd_nxt;
-		l->stats.recv_info = l->rcv_nxt;
-	}
 }
 
 static void link_print(struct tipc_link *l, const char *str)
@@ -1867,12 +1870,12 @@ static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
 	};
 
 	struct nla_map map[] = {
-		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
+		{TIPC_NLA_STATS_RX_INFO, 0},
 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
-		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
+		{TIPC_NLA_STATS_TX_INFO, 0},
 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
@@ -1947,9 +1950,9 @@ int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
 		goto attr_msg_full;
 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
 		goto attr_msg_full;
-	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
 		goto attr_msg_full;
-	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
 		goto attr_msg_full;
 
 	if (tipc_link_is_up(link))
@@ -2004,12 +2007,12 @@ static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
 	};
 
 	struct nla_map map[] = {
-		{TIPC_NLA_STATS_RX_INFO, stats->recv_info},
+		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
-		{TIPC_NLA_STATS_TX_INFO, stats->sent_info},
+		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
@@ -2076,9 +2079,9 @@ int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
 		goto attr_msg_full;
 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
 		goto attr_msg_full;
-	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->rcv_nxt))
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
 		goto attr_msg_full;
-	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->snd_nxt))
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
 		goto attr_msg_full;
 
 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);