[PATCH v2 net-next 1/2] tcp: show number of network segments in some SNMP counters

[Yafang Shao]

It is better to show the number of network segments in bellow SNMP
counters, because that could be more useful for the user.
For example, the user could easily figure out how mant packets are
dropped and how many packets are queued in the out-of-oder queue.

- LINUX_MIB_TCPRCVQDROP
- LINUX_MIB_TCPZEROWINDOWDROP
- LINUX_MIB_TCPBACKLOGDROP
- LINUX_MIB_TCPMINTTLDROP
- LINUX_MIB_TCPOFODROP
- LINUX_MIB_TCPOFOQUEUE

Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
 net/ipv4/tcp_input.c | 18 ++++++++++++------
 net/ipv4/tcp_ipv4.c  |  9 ++++++---
 net/ipv6/tcp_ipv6.c  |  6 ++++--
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 62508a2..c2ce334 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4496,7 +4496,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	tcp_ecn_check_ce(sk, skb);
 
 	if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
-		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
+		NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP,
+			      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		tcp_drop(sk, skb);
 		return;
 	}
@@ -4505,7 +4506,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	tp->pred_flags = 0;
 	inet_csk_schedule_ack(sk);
 
-	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);
+	NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE,
+		      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 	seq = TCP_SKB_CB(skb)->seq;
 	end_seq = TCP_SKB_CB(skb)->end_seq;
 	SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",
@@ -4666,7 +4668,8 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
 	skb->len = size;
 
 	if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
-		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
+		NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP,
+			      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		goto err_free;
 	}
 
@@ -4725,7 +4728,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 	 */
 	if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {
 		if (tcp_receive_window(tp) == 0) {
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
+			NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP,
+				      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 			goto out_of_window;
 		}
 
@@ -4734,7 +4738,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 		if (skb_queue_len(&sk->sk_receive_queue) == 0)
 			sk_forced_mem_schedule(sk, skb->truesize);
 		else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
+			NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP,
+				      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 			goto drop;
 		}
 
@@ -4796,7 +4801,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 		 * remembering D-SACK for its head made in previous line.
 		 */
 		if (!tcp_receive_window(tp)) {
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
+			NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP,
+				      max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 			goto out_of_window;
 		}
 		goto queue_and_out;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 09547ef..23d7cb5 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -475,7 +475,8 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 		goto out;
 
 	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
-		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
+		__NET_ADD_STATS(net, LINUX_MIB_TCPMINTTLDROP,
+				max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		goto out;
 	}
 
@@ -1633,7 +1634,8 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
 
 	if (unlikely(sk_add_backlog(sk, skb, limit))) {
 		bh_unlock_sock(sk);
-		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
+		__NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP,
+				max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		return true;
 	}
 	return false;
@@ -1790,7 +1792,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
 		}
 	}
 	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
-		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
+		__NET_ADD_STATS(net, LINUX_MIB_TCPMINTTLDROP,
+				max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		goto discard_and_relse;
 	}
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 03e6b7a..bbf7667 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -391,7 +391,8 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		goto out;
 
 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
-		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
+		__NET_ADD_STATS(net, LINUX_MIB_TCPMINTTLDROP,
+				max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		goto out;
 	}
 
@@ -1523,7 +1524,8 @@ static int tcp_v6_rcv(struct sk_buff *skb)
 		}
 	}
 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
-		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
+		__NET_ADD_STATS(net, LINUX_MIB_TCPMINTTLDROP,
+				max_t(u16, 1, skb_shinfo(skb)->gso_segs));
 		goto discard_and_relse;
 	}
 
-- 
1.8.3.1