The client's sk_state will be set to TCP_ESTABLISHED if the
server replay the client's connect request.
However, if the client has pending signal, its sk_state will
be set to TCP_CLOSE without notify the server, so the server
will hold the corrupt connection.
client server
1. sk_state=TCP_SYN_SENT |
2. call ->connect() |
3. wait reply |
| 4. sk_state=TCP_ESTABLISHED
| 5. insert to connected list
| 6. reply to the client
7. sk_state=TCP_ESTABLISHED |
8. insert to connected list |
9. *signal pending* <--------------------- the user kill client
10. sk_state=TCP_CLOSE |
client is exiting... |
11. call ->release() |
virtio_transport_close
if (!(sk->sk_state == TCP_ESTABLISHED ||
sk->sk_state == TCP_CLOSING))
return true; <------------- return at here
As a result, the server cannot notice the connection is corrupt.
So the client should notify the peer in this case.
Cc: David S. Miller <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Stefano Garzarella <[email protected]>
Cc: Jorgen Hansen <[email protected]>
Cc: Norbert Slusarek <[email protected]>
Cc: Andra Paraschiv <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: David Brazdil <[email protected]>
Cc: Alexander Popov <[email protected]>
Signed-off-by: lixianming <[email protected]>
Signed-off-by: Longpeng(Mike) <[email protected]>
---
net/vmw_vsock/af_vsock.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 92a72f0..d5df908 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
lock_sock(sk);
if (signal_pending(current)) {
+ vsock_send_shutdown(sk, SHUTDOWN_MASK);
err = sock_intr_errno(timeout);
sk->sk_state = TCP_CLOSE;
sock->state = SS_UNCONNECTED;
--
1.8.3.1
Hi,
thanks for this patch, comments below...
On Tue, May 11, 2021 at 05:41:27PM +0800, Longpeng(Mike) wrote:
>The client's sk_state will be set to TCP_ESTABLISHED if the
>server replay the client's connect request.
>However, if the client has pending signal, its sk_state will
>be set to TCP_CLOSE without notify the server, so the server
>will hold the corrupt connection.
>
> client server
>
>1. sk_state=TCP_SYN_SENT |
>2. call ->connect() |
>3. wait reply |
> | 4. sk_state=TCP_ESTABLISHED
> | 5. insert to connected list
> | 6. reply to the client
>7. sk_state=TCP_ESTABLISHED |
>8. insert to connected list |
>9. *signal pending* <--------------------- the user kill client
>10. sk_state=TCP_CLOSE |
>client is exiting... |
>11. call ->release() |
> virtio_transport_close
> if (!(sk->sk_state == TCP_ESTABLISHED ||
> sk->sk_state == TCP_CLOSING))
> return true; <------------- return at here
>As a result, the server cannot notice the connection is corrupt.
>So the client should notify the peer in this case.
>
>Cc: David S. Miller <[email protected]>
>Cc: Jakub Kicinski <[email protected]>
>Cc: Stefano Garzarella <[email protected]>
>Cc: Jorgen Hansen <[email protected]>
>Cc: Norbert Slusarek <[email protected]>
>Cc: Andra Paraschiv <[email protected]>
>Cc: Colin Ian King <[email protected]>
>Cc: David Brazdil <[email protected]>
>Cc: Alexander Popov <[email protected]>
>Signed-off-by: lixianming <[email protected]>
>Signed-off-by: Longpeng(Mike) <[email protected]>
>---
> net/vmw_vsock/af_vsock.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 92a72f0..d5df908 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
> lock_sock(sk);
>
> if (signal_pending(current)) {
>+ vsock_send_shutdown(sk, SHUTDOWN_MASK);
I see the issue, but I'm not sure is okay to send the shutdown in any
case, think about the server didn't setup the connection.
Maybe is better to set TCP_CLOSING if the socket state was
TCP_ESTABLISHED, so the shutdown will be handled by the
transport->release() as usual.
What do you think?
Anyway, also without the patch, the server should receive a RST if it
sends any data to the client, but of course, is better to let it know
the socket is closed in advance.
Thanks,
Stefano
Hi Stefano,
> -----Original Message-----
> From: Stefano Garzarella [mailto:[email protected]]
> Sent: Thursday, May 13, 2021 5:42 PM
> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> <[email protected]>
> Cc: [email protected]; [email protected]; Gonglei (Arei)
> <[email protected]>; Subo (Subo, Cloud Infrastructure Service Product
> Dept.) <[email protected]>; David S . Miller <[email protected]>; Jakub
> Kicinski <[email protected]>; Jorgen Hansen <[email protected]>; Norbert
> Slusarek <[email protected]>; Andra Paraschiv <[email protected]>;
> Colin Ian King <[email protected]>; David Brazdil
> <[email protected]>; Alexander Popov <[email protected]>;
> lixianming (E) <[email protected]>
> Subject: Re: [RFC] vsock: notify server to shutdown when client has pending
> signal
>
> Hi,
> thanks for this patch, comments below...
>
> On Tue, May 11, 2021 at 05:41:27PM +0800, Longpeng(Mike) wrote:
> >The client's sk_state will be set to TCP_ESTABLISHED if the server
> >replay the client's connect request.
> >However, if the client has pending signal, its sk_state will be set to
> >TCP_CLOSE without notify the server, so the server will hold the
> >corrupt connection.
> >
> > client server
> >
> >1. sk_state=TCP_SYN_SENT |
> >2. call ->connect() |
> >3. wait reply |
> > | 4. sk_state=TCP_ESTABLISHED
> > | 5. insert to connected list
> > | 6. reply to the client
> >7. sk_state=TCP_ESTABLISHED |
> >8. insert to connected list |
> >9. *signal pending* <--------------------- the user kill client
> >10. sk_state=TCP_CLOSE |
> >client is exiting... |
> >11. call ->release() |
> > virtio_transport_close
> > if (!(sk->sk_state == TCP_ESTABLISHED ||
> > sk->sk_state == TCP_CLOSING))
> > return true; <------------- return at here As a result, the server
> >cannot notice the connection is corrupt.
> >So the client should notify the peer in this case.
> >
> >Cc: David S. Miller <[email protected]>
> >Cc: Jakub Kicinski <[email protected]>
> >Cc: Stefano Garzarella <[email protected]>
> >Cc: Jorgen Hansen <[email protected]>
> >Cc: Norbert Slusarek <[email protected]>
> >Cc: Andra Paraschiv <[email protected]>
> >Cc: Colin Ian King <[email protected]>
> >Cc: David Brazdil <[email protected]>
> >Cc: Alexander Popov <[email protected]>
> >Signed-off-by: lixianming <[email protected]>
> >Signed-off-by: Longpeng(Mike) <[email protected]>
> >---
> > net/vmw_vsock/af_vsock.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index
> >92a72f0..d5df908 100644
> >--- a/net/vmw_vsock/af_vsock.c
> >+++ b/net/vmw_vsock/af_vsock.c
> >@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket *sock,
> struct sockaddr *addr,
> > lock_sock(sk);
> >
> > if (signal_pending(current)) {
> >+ vsock_send_shutdown(sk, SHUTDOWN_MASK);
>
> I see the issue, but I'm not sure is okay to send the shutdown in any case,
> think about the server didn't setup the connection.
>
> Maybe is better to set TCP_CLOSING if the socket state was TCP_ESTABLISHED,
> so the shutdown will be handled by the
> transport->release() as usual.
>
> What do you think?
>
Your method looks more gracefully, we'll try it and get back to you, thanks.
> Anyway, also without the patch, the server should receive a RST if it
> sends any data to the client, but of course, is better to let it know
> the socket is closed in advance.
>
Yes, agree.
> Thanks,
> Stefano
Hi Stefano,
> -----Original Message-----
> From: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> [mailto:[email protected]]
> Sent: Thursday, May 13, 2021 6:36 PM
> To: Stefano Garzarella <[email protected]>
> Cc: [email protected]; [email protected]; Gonglei (Arei)
> <[email protected]>; Subo (Subo, Cloud Infrastructure Service Product
> Dept.) <[email protected]>; David S . Miller <[email protected]>; Jakub
> Kicinski <[email protected]>; Jorgen Hansen <[email protected]>; Norbert
> Slusarek <[email protected]>; Andra Paraschiv <[email protected]>;
> Colin Ian King <[email protected]>; David Brazdil
> <[email protected]>; Alexander Popov <[email protected]>;
> lixianming (E) <[email protected]>
> Subject: RE: [RFC] vsock: notify server to shutdown when client has pending
> signal
>
> Hi Stefano,
>
> > -----Original Message-----
> > From: Stefano Garzarella [mailto:[email protected]]
> > Sent: Thursday, May 13, 2021 5:42 PM
> > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> > <[email protected]>
> > Cc: [email protected]; [email protected]; Gonglei
> > (Arei) <[email protected]>; Subo (Subo, Cloud Infrastructure
> > Service Product
> > Dept.) <[email protected]>; David S . Miller <[email protected]>;
> > Jakub Kicinski <[email protected]>; Jorgen Hansen <[email protected]>;
> > Norbert Slusarek <[email protected]>; Andra Paraschiv
> > <[email protected]>; Colin Ian King <[email protected]>;
> > David Brazdil <[email protected]>; Alexander Popov
> > <[email protected]>; lixianming (E) <[email protected]>
> > Subject: Re: [RFC] vsock: notify server to shutdown when client has
> > pending signal
> >
> > Hi,
> > thanks for this patch, comments below...
> >
> > On Tue, May 11, 2021 at 05:41:27PM +0800, Longpeng(Mike) wrote:
> > >The client's sk_state will be set to TCP_ESTABLISHED if the server
> > >replay the client's connect request.
> > >However, if the client has pending signal, its sk_state will be set
> > >to TCP_CLOSE without notify the server, so the server will hold the
> > >corrupt connection.
> > >
> > > client server
> > >
> > >1. sk_state=TCP_SYN_SENT |
> > >2. call ->connect() |
> > >3. wait reply |
> > > | 4. sk_state=TCP_ESTABLISHED
> > > | 5. insert to connected list
> > > | 6. reply to the client
> > >7. sk_state=TCP_ESTABLISHED |
> > >8. insert to connected list |
> > >9. *signal pending* <--------------------- the user kill client
> > >10. sk_state=TCP_CLOSE |
> > >client is exiting... |
> > >11. call ->release() |
> > > virtio_transport_close
> > > if (!(sk->sk_state == TCP_ESTABLISHED ||
> > > sk->sk_state == TCP_CLOSING))
> > > return true; <------------- return at here As a result, the server
> > >cannot notice the connection is corrupt.
> > >So the client should notify the peer in this case.
> > >
> > >Cc: David S. Miller <[email protected]>
> > >Cc: Jakub Kicinski <[email protected]>
> > >Cc: Stefano Garzarella <[email protected]>
> > >Cc: Jorgen Hansen <[email protected]>
> > >Cc: Norbert Slusarek <[email protected]>
> > >Cc: Andra Paraschiv <[email protected]>
> > >Cc: Colin Ian King <[email protected]>
> > >Cc: David Brazdil <[email protected]>
> > >Cc: Alexander Popov <[email protected]>
> > >Signed-off-by: lixianming <[email protected]>
> > >Signed-off-by: Longpeng(Mike) <[email protected]>
> > >---
> > > net/vmw_vsock/af_vsock.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > >index
> > >92a72f0..d5df908 100644
> > >--- a/net/vmw_vsock/af_vsock.c
> > >+++ b/net/vmw_vsock/af_vsock.c
> > >@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket
> > >*sock,
> > struct sockaddr *addr,
> > > lock_sock(sk);
> > >
> > > if (signal_pending(current)) {
> > >+ vsock_send_shutdown(sk, SHUTDOWN_MASK);
> >
> > I see the issue, but I'm not sure is okay to send the shutdown in any
> > case, think about the server didn't setup the connection.
> >
> > Maybe is better to set TCP_CLOSING if the socket state was
> > TCP_ESTABLISHED, so the shutdown will be handled by the
> > transport->release() as usual.
> >
> > What do you think?
> >
>
> Your method looks more gracefully, we'll try it and get back to you, thanks.
>
As your suggestion, the following code can solve the problem:
if (signal_pending(current)) {
err = sock_intr_errno(timeout);
- sk->sk_state = TCP_CLOSE;
+ sk->sk_state = TCP_CLOSING;
sock->state = SS_UNCONNECTED;
vsock_transport_cancel_pkt(vsk);
goto out_wait;
This will send shutdown to the server even if the connection is not established, but
I don't see any side effects yet, right ?
The problem is also in the timeout case, we should fix it together ?
> > Anyway, also without the patch, the server should receive a RST if it
> > sends any data to the client, but of course, is better to let it know
> > the socket is closed in advance.
> >
>
> Yes, agree.
>
> > Thanks,
> > Stefano
On Mon, May 17, 2021 at 02:18:51AM +0000, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) wrote:
>Hi Stefano,
>
>> -----Original Message-----
>> From: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
>> [mailto:[email protected]]
>> Sent: Thursday, May 13, 2021 6:36 PM
>> To: Stefano Garzarella <[email protected]>
>> Cc: [email protected]; [email protected]; Gonglei (Arei)
>> <[email protected]>; Subo (Subo, Cloud Infrastructure Service Product
>> Dept.) <[email protected]>; David S . Miller <[email protected]>; Jakub
>> Kicinski <[email protected]>; Jorgen Hansen <[email protected]>; Norbert
>> Slusarek <[email protected]>; Andra Paraschiv <[email protected]>;
>> Colin Ian King <[email protected]>; David Brazdil
>> <[email protected]>; Alexander Popov <[email protected]>;
>> lixianming (E) <[email protected]>
>> Subject: RE: [RFC] vsock: notify server to shutdown when client has pending
>> signal
>>
>> Hi Stefano,
>>
>> > -----Original Message-----
>> > From: Stefano Garzarella [mailto:[email protected]]
>> > Sent: Thursday, May 13, 2021 5:42 PM
>> > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
>> > <[email protected]>
>> > Cc: [email protected]; [email protected]; Gonglei
>> > (Arei) <[email protected]>; Subo (Subo, Cloud Infrastructure
>> > Service Product
>> > Dept.) <[email protected]>; David S . Miller <[email protected]>;
>> > Jakub Kicinski <[email protected]>; Jorgen Hansen <[email protected]>;
>> > Norbert Slusarek <[email protected]>; Andra Paraschiv
>> > <[email protected]>; Colin Ian King <[email protected]>;
>> > David Brazdil <[email protected]>; Alexander Popov
>> > <[email protected]>; lixianming (E) <[email protected]>
>> > Subject: Re: [RFC] vsock: notify server to shutdown when client has
>> > pending signal
>> >
>> > Hi,
>> > thanks for this patch, comments below...
>> >
>> > On Tue, May 11, 2021 at 05:41:27PM +0800, Longpeng(Mike) wrote:
>> > >The client's sk_state will be set to TCP_ESTABLISHED if the server
>> > >replay the client's connect request.
>> > >However, if the client has pending signal, its sk_state will be set
>> > >to TCP_CLOSE without notify the server, so the server will hold the
>> > >corrupt connection.
>> > >
>> > > client server
>> > >
>> > >1. sk_state=TCP_SYN_SENT |
>> > >2. call ->connect() |
>> > >3. wait reply |
>> > > | 4. sk_state=TCP_ESTABLISHED
>> > > | 5. insert to connected list
>> > > | 6. reply to the client
>> > >7. sk_state=TCP_ESTABLISHED |
>> > >8. insert to connected list |
>> > >9. *signal pending* <--------------------- the user kill client
>> > >10. sk_state=TCP_CLOSE |
>> > >client is exiting... |
>> > >11. call ->release() |
>> > > virtio_transport_close
>> > > if (!(sk->sk_state == TCP_ESTABLISHED ||
>> > > sk->sk_state == TCP_CLOSING))
>> > > return true; <------------- return at here As a result, the server
>> > >cannot notice the connection is corrupt.
>> > >So the client should notify the peer in this case.
>> > >
>> > >Cc: David S. Miller <[email protected]>
>> > >Cc: Jakub Kicinski <[email protected]>
>> > >Cc: Stefano Garzarella <[email protected]>
>> > >Cc: Jorgen Hansen <[email protected]>
>> > >Cc: Norbert Slusarek <[email protected]>
>> > >Cc: Andra Paraschiv <[email protected]>
>> > >Cc: Colin Ian King <[email protected]>
>> > >Cc: David Brazdil <[email protected]>
>> > >Cc: Alexander Popov <[email protected]>
>> > >Signed-off-by: lixianming <[email protected]>
>> > >Signed-off-by: Longpeng(Mike) <[email protected]>
>> > >---
>> > > net/vmw_vsock/af_vsock.c | 1 +
>> > > 1 file changed, 1 insertion(+)
>> > >
>> > >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> > >index
>> > >92a72f0..d5df908 100644
>> > >--- a/net/vmw_vsock/af_vsock.c
>> > >+++ b/net/vmw_vsock/af_vsock.c
>> > >@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket
>> > >*sock,
>> > struct sockaddr *addr,
>> > > lock_sock(sk);
>> > >
>> > > if (signal_pending(current)) {
>> > >+ vsock_send_shutdown(sk, SHUTDOWN_MASK);
>> >
>> > I see the issue, but I'm not sure is okay to send the shutdown in any
>> > case, think about the server didn't setup the connection.
>> >
>> > Maybe is better to set TCP_CLOSING if the socket state was
>> > TCP_ESTABLISHED, so the shutdown will be handled by the
>> > transport->release() as usual.
>> >
>> > What do you think?
>> >
>>
>> Your method looks more gracefully, we'll try it and get back to you,
>> thanks.
>>
>
>As your suggestion, the following code can solve the problem:
>
> if (signal_pending(current)) {
> err = sock_intr_errno(timeout);
>- sk->sk_state = TCP_CLOSE;
>+ sk->sk_state = TCP_CLOSING;
> sock->state = SS_UNCONNECTED;
> vsock_transport_cancel_pkt(vsk);
> goto out_wait;
>
>This will send shutdown to the server even if the connection is not established, but
>I don't see any side effects yet, right ?
Should we set TCP_CLOSING only if sk_state was TCP_ESTABLISHED?
>
>The problem is also in the timeout case, we should fix it together ?
>
I'm not sure, if we reach the timeout, it should mean that the other
peer never answered, so why take care to notify it?
Thanks,
Stefano