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Message-Id: <20210527011155.10097-7-xiyou.wangcong@gmail.com>
Date: Wed, 26 May 2021 18:11:53 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org, Cong Wang <cong.wang@...edance.com>,
John Fastabend <john.fastabend@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
Jakub Sitnicki <jakub@...udflare.com>,
Lorenz Bauer <lmb@...udflare.com>
Subject: [Patch bpf v3 6/8] skmsg: teach sk_psock_verdict_apply() to return errors
From: Cong Wang <cong.wang@...edance.com>
Currently sk_psock_verdict_apply() is void, but it handles some
error conditions too. Its caller is impossible to learn whether
it succeeds or fails, especially sk_psock_verdict_recv().
Make it return int to indicate error cases and propagate errors
to callers properly.
Fixes: ef5659280eb1 ("bpf, sockmap: Allow skipping sk_skb parser program")
Cc: John Fastabend <john.fastabend@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Jakub Sitnicki <jakub@...udflare.com>
Cc: Lorenz Bauer <lmb@...udflare.com>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
net/core/skmsg.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 5464477e2d3d..e3d210811db4 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -824,7 +824,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
}
EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
-static void sk_psock_skb_redirect(struct sk_buff *skb)
+static int sk_psock_skb_redirect(struct sk_buff *skb)
{
struct sk_psock *psock_other;
struct sock *sk_other;
@@ -835,7 +835,7 @@ static void sk_psock_skb_redirect(struct sk_buff *skb)
*/
if (unlikely(!sk_other)) {
kfree_skb(skb);
- return;
+ return -EIO;
}
psock_other = sk_psock(sk_other);
/* This error indicates the socket is being torn down or had another
@@ -845,19 +845,20 @@ static void 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);
- return;
+ 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);
- return;
+ return -EIO;
}
skb_queue_tail(&psock_other->ingress_skb, skb);
schedule_work(&psock_other->work);
spin_unlock_bh(&psock_other->ingress_lock);
+ return 0;
}
static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict)
@@ -894,14 +895,15 @@ int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
}
EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
-static void sk_psock_verdict_apply(struct sk_psock *psock,
- struct sk_buff *skb, int verdict)
+static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
+ int verdict)
{
struct sock *sk_other;
- int err = -EIO;
+ int err = 0;
switch (verdict) {
case __SK_PASS:
+ err = -EIO;
sk_other = psock->sk;
if (sock_flag(sk_other, SOCK_DEAD) ||
!sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
@@ -934,13 +936,15 @@ static void sk_psock_verdict_apply(struct sk_psock *psock,
}
break;
case __SK_REDIRECT:
- sk_psock_skb_redirect(skb);
+ err = sk_psock_skb_redirect(skb);
break;
case __SK_DROP:
default:
out_free:
kfree_skb(skb);
}
+
+ return err;
}
static void sk_psock_write_space(struct sock *sk)
@@ -1107,7 +1111,8 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
skb->sk = NULL;
}
- sk_psock_verdict_apply(psock, skb, ret);
+ if (sk_psock_verdict_apply(psock, skb, ret) < 0)
+ len = 0;
out:
rcu_read_unlock();
return len;
--
2.25.1
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