[PATCH stable 4.4 V2 1/6] tcp: increment sk_drops for dropped rx packets

Mao Wenan
2018-09-14T08:14:38Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 532182cd610782db8c18230c2747626562032205 ]

Now ss can report sk_drops, we can instruct TCP to increment
this per socket counter when it drops an incoming frame, to refine
monitoring and debugging.

Following patch takes care of listeners drops.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
---
include/net/sock.h | 7 +++++++
net/ipv4/tcp_input.c | 33 ++++++++++++++++++++-------------
net/ipv4/tcp_ipv4.c | 1 +
net/ipv6/tcp_ipv6.c | 1 +
4 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 3d5ff74..5770757 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2139,6 +2139,13 @@ sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
SOCK_SKB_CB(skb)->dropcount = atomic_read(&sk->sk_drops);
}

+static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
+{
+ int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
+
+ atomic_add(segs, &sk->sk_drops);
+}
+
void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb);
void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9c4c6cd..9df4cbb 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4296,6 +4296,12 @@ static bool tcp_try_coalesce(struct sock *sk,
return true;
}

+static void tcp_drop(struct sock *sk, struct sk_buff *skb)
+{
+ sk_drops_add(sk, skb);
+ __kfree_skb(skb);
+}
+
/* This one checks to see if we can put data from the
* out_of_order queue into the receive_queue.
*/
@@ -4320,7 +4326,7 @@ static void tcp_ofo_queue(struct sock *sk)
__skb_unlink(skb, &tp->out_of_order_queue);
if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
SOCK_DEBUG(sk, "ofo packet was already received\n");
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
continue;
}
SOCK_DEBUG(sk, "ofo requeuing : rcv_next %X seq %X - %X\n",
@@ -4372,7 +4378,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)

if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFODROP);
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
return;
}

@@ -4436,7 +4442,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
/* All the bits are present. Drop. */
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
skb = NULL;
tcp_dsack_set(sk, seq, end_seq);
goto add_sack;
@@ -4475,7 +4481,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
TCP_SKB_CB(skb1)->end_seq);
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
- __kfree_skb(skb1);
+ tcp_drop(sk, skb1);
}

add_sack:
@@ -4558,12 +4564,13 @@ err:
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
- int eaten = -1;
bool fragstolen = false;
+ int eaten = -1;

- if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq)
- goto drop;
-
+ if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
+ __kfree_skb(skb);
+ return;
+ }
skb_dst_drop(skb);
__skb_pull(skb, tcp_hdr(skb)->doff * 4);

@@ -4645,7 +4652,7 @@ out_of_window:
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_schedule_ack(sk);
drop:
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
return;
}

@@ -5236,7 +5243,7 @@ syn_challenge:
return true;

discard:
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
return false;
}

@@ -5454,7 +5461,7 @@ csum_error:
TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);

discard:
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
}
EXPORT_SYMBOL(tcp_rcv_established);

@@ -5684,7 +5691,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
TCP_DELACK_MAX, TCP_RTO_MAX);

discard:
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
return 0;
} else {
tcp_send_ack(sk);
@@ -6041,7 +6048,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)

if (!queued) {
discard:
- __kfree_skb(skb);
+ tcp_drop(sk, skb);
}
return 0;
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index eeda67c..01715fc 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1716,6 +1716,7 @@ discard_it:
return 0;

discard_and_relse:
+ sk_drops_add(sk, skb);
sock_put(sk);
goto discard_it;

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 90abe88..d6c1911 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1505,6 +1505,7 @@ discard_it:
return 0;

discard_and_relse:
+ sk_drops_add(sk, skb);
sock_put(sk);
goto discard_it;

--
1.8.3.1