* [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress
@ 2021-09-17 1:32 Liu Jian
2021-09-17 22:34 ` John Fastabend
2021-09-20 1:14 ` Cong Wang
0 siblings, 2 replies; 4+ messages in thread
From: Liu Jian @ 2021-09-17 1:32 UTC (permalink / raw)
To: john.fastabend, daniel, jakub, lmb, davem, kuba, netdev, bpf; +Cc: liujian56
If sockmap enable strparser, there are lose offset info in
sk_psock_skb_ingress. If the length determined by parse_msg function
is not skb->len, the skb will be converted to sk_msg multiple times,
and userspace app will get the data multiple times.
Fix this by get the offset and length from strp_msg.
Signed-off-by: Liu Jian <liujian56@huawei.com>
---
v1->v2: fix build error when disable CONFIG_BPF_STREAM_PARSER
net/core/skmsg.c | 51 ++++++++++++++++++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 10 deletions(-)
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 2d6249b28928..c958e3642cb3 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -9,6 +9,10 @@
#include <net/tcp.h>
#include <net/tls.h>
+#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
+static void sk_psock_strp_data_ready(struct sock *sk);
+#endif
+
static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
{
if (msg->sg.end > msg->sg.start &&
@@ -494,6 +498,7 @@ static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
}
static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
+ u32 off, u32 len,
struct sk_psock *psock,
struct sock *sk,
struct sk_msg *msg)
@@ -507,11 +512,11 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
*/
if (skb_linearize(skb))
return -EAGAIN;
- num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
+ num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
if (unlikely(num_sge < 0))
return num_sge;
- copied = skb->len;
+ copied = len;
msg->sg.start = 0;
msg->sg.size = copied;
msg->sg.end = num_sge;
@@ -522,9 +527,11 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
return copied;
}
-static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb);
+static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
+ u32 off, u32 len);
-static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
+static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
+ u32 off, u32 len)
{
struct sock *sk = psock->sk;
struct sk_msg *msg;
@@ -535,7 +542,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
* correctly.
*/
if (unlikely(skb->sk == sk))
- return sk_psock_skb_ingress_self(psock, skb);
+ return sk_psock_skb_ingress_self(psock, skb, off, len);
msg = sk_psock_create_ingress_msg(sk, skb);
if (!msg)
return -EAGAIN;
@@ -547,7 +554,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
* into user buffers.
*/
skb_set_owner_r(skb, sk);
- err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
+ err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
if (err < 0)
kfree(msg);
return err;
@@ -557,7 +564,8 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
* skb. In this case we do not need to check memory limits or skb_set_owner_r
* because the skb is already accounted for here.
*/
-static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb)
+static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
+ u32 off, u32 len)
{
struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
struct sock *sk = psock->sk;
@@ -567,7 +575,7 @@ static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb
return -EAGAIN;
sk_msg_init(msg);
skb_set_owner_r(skb, sk);
- err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
+ err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
if (err < 0)
kfree(msg);
return err;
@@ -581,7 +589,7 @@ static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
return -EAGAIN;
return skb_send_sock(psock->sk, skb, off, len);
}
- return sk_psock_skb_ingress(psock, skb);
+ return sk_psock_skb_ingress(psock, skb, off, len);
}
static void sk_psock_skb_state(struct sk_psock *psock,
@@ -604,6 +612,9 @@ static void sk_psock_backlog(struct work_struct *work)
{
struct sk_psock *psock = container_of(work, struct sk_psock, work);
struct sk_psock_work_state *state = &psock->work_state;
+#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
+ struct strp_msg *stm = NULL;
+#endif
struct sk_buff *skb = NULL;
bool ingress;
u32 len, off;
@@ -624,6 +635,13 @@ static void sk_psock_backlog(struct work_struct *work)
while ((skb = skb_dequeue(&psock->ingress_skb))) {
len = skb->len;
off = 0;
+#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
+ if (psock->sk->sk_data_ready == sk_psock_strp_data_ready) {
+ stm = strp_msg(skb);
+ off = stm->offset;
+ len = stm->full_len;
+ }
+#endif
start:
ingress = skb_bpf_ingress(skb);
skb_bpf_redirect_clear(skb);
@@ -930,6 +948,10 @@ static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
{
struct sock *sk_other;
int err = 0;
+#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
+ struct strp_msg *stm = NULL;
+#endif
+ u32 len, off;
switch (verdict) {
case __SK_PASS:
@@ -949,7 +971,16 @@ static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
* retrying later from workqueue.
*/
if (skb_queue_empty(&psock->ingress_skb)) {
- err = sk_psock_skb_ingress_self(psock, skb);
+ len = skb->len;
+ off = 0;
+#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
+ if (psock->sk->sk_data_ready == sk_psock_strp_data_ready) {
+ stm = strp_msg(skb);
+ off = stm->offset;
+ len = stm->full_len;
+ }
+#endif
+ err = sk_psock_skb_ingress_self(psock, skb, off, len);
}
if (err < 0) {
spin_lock_bh(&psock->ingress_lock);
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* RE: [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress
2021-09-17 1:32 [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress Liu Jian
@ 2021-09-17 22:34 ` John Fastabend
2021-09-20 1:14 ` Cong Wang
1 sibling, 0 replies; 4+ messages in thread
From: John Fastabend @ 2021-09-17 22:34 UTC (permalink / raw)
To: Liu Jian, john.fastabend, daniel, jakub, lmb, davem, kuba, netdev, bpf
Cc: liujian56
Liu Jian wrote:
> If sockmap enable strparser, there are lose offset info in
> sk_psock_skb_ingress. If the length determined by parse_msg function
> is not skb->len, the skb will be converted to sk_msg multiple times,
> and userspace app will get the data multiple times.
>
> Fix this by get the offset and length from strp_msg.
>
> Signed-off-by: Liu Jian <liujian56@huawei.com>
> ---
> v1->v2: fix build error when disable CONFIG_BPF_STREAM_PARSER
>
LGTM thanks.
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress
2021-09-17 1:32 [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress Liu Jian
2021-09-17 22:34 ` John Fastabend
@ 2021-09-20 1:14 ` Cong Wang
2021-09-22 2:21 ` liujian (CE)
1 sibling, 1 reply; 4+ messages in thread
From: Cong Wang @ 2021-09-20 1:14 UTC (permalink / raw)
To: Liu Jian
Cc: John Fastabend, Daniel Borkmann, Jakub Sitnicki, Lorenz Bauer,
David Miller, Jakub Kicinski, Linux Kernel Network Developers,
bpf
On Fri, Sep 17, 2021 at 3:05 AM Liu Jian <liujian56@huawei.com> wrote:
> @@ -624,6 +635,13 @@ static void sk_psock_backlog(struct work_struct *work)
> while ((skb = skb_dequeue(&psock->ingress_skb))) {
> len = skb->len;
> off = 0;
> +#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
> + if (psock->sk->sk_data_ready == sk_psock_strp_data_ready) {
> + stm = strp_msg(skb);
> + off = stm->offset;
> + len = stm->full_len;
> + }
> +#endif
How does this work? You are testing psock->sk->sk_data_ready here
but it is already the dest sock here, so, if we redirect a strp_msg() from
strp socket to non-strp socket, this does not work at all?
And this code looks ugly itself. If you want to distinguish this type of
packet from others, you can add a bit in, for example skb->_sk_redir.
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress
2021-09-20 1:14 ` Cong Wang
@ 2021-09-22 2:21 ` liujian (CE)
0 siblings, 0 replies; 4+ messages in thread
From: liujian (CE) @ 2021-09-22 2:21 UTC (permalink / raw)
To: Cong Wang
Cc: John Fastabend, Daniel Borkmann, Jakub Sitnicki, Lorenz Bauer,
David Miller, Jakub Kicinski, Linux Kernel Network Developers,
bpf
> -----Original Message-----
> From: Cong Wang [mailto:xiyou.wangcong@gmail.com]
> Sent: Monday, September 20, 2021 9:14 AM
> To: liujian (CE) <liujian56@huawei.com>
> Cc: John Fastabend <john.fastabend@gmail.com>; Daniel Borkmann
> <daniel@iogearbox.net>; Jakub Sitnicki <jakub@cloudflare.com>; Lorenz
> Bauer <lmb@cloudflare.com>; David Miller <davem@davemloft.net>; Jakub
> Kicinski <kuba@kernel.org>; Linux Kernel Network Developers
> <netdev@vger.kernel.org>; bpf <bpf@vger.kernel.org>
> Subject: Re: [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress
>
> On Fri, Sep 17, 2021 at 3:05 AM Liu Jian <liujian56@huawei.com> wrote:
> > @@ -624,6 +635,13 @@ static void sk_psock_backlog(struct work_struct
> *work)
> > while ((skb = skb_dequeue(&psock->ingress_skb))) {
> > len = skb->len;
> > off = 0;
> > +#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
> > + if (psock->sk->sk_data_ready == sk_psock_strp_data_ready) {
> > + stm = strp_msg(skb);
> > + off = stm->offset;
> > + len = stm->full_len;
> > + }
> > +#endif
>
> How does this work? You are testing psock->sk->sk_data_ready here but it is
> already the dest sock here, so, if we redirect a strp_msg() from strp socket to
> non-strp socket, this does not work at all?
>
Yes, it is not work in this case, I did not consider this case.
> And this code looks ugly itself. If you want to distinguish this type of packet
> from others, you can add a bit in, for example skb->_sk_redir.
It looks better this way.
I will send v3 later. Thank you~
>
> Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-09-17 1:32 [PATCH v2] skmsg: lose offset info in sk_psock_skb_ingress Liu Jian
2021-09-17 22:34 ` John Fastabend
2021-09-20 1:14 ` Cong Wang
2021-09-22 2:21 ` liujian (CE)
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