[PATCH 5.13 04/35] skmsg: Increase sk->sk_drops when dropping packets

Greg Kroah-Hartman
2021-08-06T08:24:41Z

From: Cong Wang <cong.wang@bytedance.com>

[ Upstream commit 781dd0431eb549f9cb1fdddf91a50d985febe884 ]

It is hard to observe packet drops without increasing relevant
drop counters, here we should increase sk->sk_drops which is
a protocol-independent counter. Fortunately psock is always
associated with a struct sock, we can just use psock->sk.

Suggested-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210615021342.7416-9-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/skmsg.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 45b3a3adc886..d428368a0d87 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -607,6 +607,12 @@ static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
return sk_psock_skb_ingress(psock, skb);
}

+static void sock_drop(struct sock *sk, struct sk_buff *skb)
+{
+ sk_drops_add(sk, skb);
+ kfree_skb(skb);
+}
+
static void sk_psock_backlog(struct work_struct *work)
{
struct sk_psock *psock = container_of(work, struct sk_psock, work);
@@ -646,7 +652,7 @@ static void sk_psock_backlog(struct work_struct *work)
/* Hard errors break pipe and stop xmit. */
sk_psock_report_error(psock, ret ? -ret : EPIPE);
sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
- kfree_skb(skb);
+ sock_drop(psock->sk, skb);
goto end;
}
off += ret;
@@ -737,7 +743,7 @@ static void __sk_psock_zap_ingress(struct sk_psock *psock)

while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
skb_bpf_redirect_clear(skb);
- kfree_skb(skb);
+ sock_drop(psock->sk, skb);
}
__sk_psock_purge_ingress_msg(psock);
}
@@ -863,7 +869,7 @@ static int sk_psock_skb_redirect(struct sk_buff *skb)
* return code, but then didn't set a redirect interface.
*/
if (unlikely(!sk_other)) {
- kfree_skb(skb);
+ sock_drop(from->sk, skb);
return -EIO;
}
psock_other = sk_psock(sk_other);
@@ -873,14 +879,14 @@ static int sk_psock_skb_redirect(struct sk_buff *skb)
*/
if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
skb_bpf_redirect_clear(skb);
- kfree_skb(skb);
+ sock_drop(from->sk, skb);
return -EIO;
}
spin_lock_bh(&psock_other->ingress_lock);
if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
spin_unlock_bh(&psock_other->ingress_lock);
skb_bpf_redirect_clear(skb);
- kfree_skb(skb);
+ sock_drop(from->sk, skb);
return -EIO;
}

@@ -970,7 +976,7 @@ static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
case __SK_DROP:
default:
out_free:
- kfree_skb(skb);
+ sock_drop(psock->sk, skb);
}

return err;
@@ -1005,7 +1011,7 @@ static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
sk = strp->sk;
psock = sk_psock(sk);
if (unlikely(!psock)) {
- kfree_skb(skb);
+ sock_drop(sk, skb);
goto out;
}
prog = READ_ONCE(psock->progs.stream_verdict);
@@ -1126,7 +1132,7 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
psock = sk_psock(sk);
if (unlikely(!psock)) {
len = 0;
- kfree_skb(skb);
+ sock_drop(sk, skb);
goto out;
}
prog = READ_ONCE(psock->progs.stream_verdict);
--
2.30.2