* Re: [PATCH 1/1] Per socket value for max datagram queue length
2014-01-22 15:11 [PATCH 1/1] Per socket value for max datagram queue length Dan Ballard
@ 2014-01-22 15:20 ` Hannes Frederic Sowa
2014-01-22 15:32 ` Hannes Frederic Sowa
2014-01-22 15:30 ` Eric Dumazet
2014-01-22 15:32 ` Daniel Borkmann
2 siblings, 1 reply; 5+ messages in thread
From: Hannes Frederic Sowa @ 2014-01-22 15:20 UTC (permalink / raw)
To: Dan Ballard
Cc: Lennart Poettering, kay.sievers, Arnd Bergmann, David S. Miller,
Eric Dumazet, Eliezer Tamir, Neil Horman, Li Zefan, linux-arch,
linux-kernel, netdev
On Wed, Jan 22, 2014 at 07:11:20AM -0800, Dan Ballard wrote:
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 5393b4b..1ff69d1 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -915,6 +915,10 @@ set_rcvbuf:
> sk->sk_max_pacing_rate);
> break;
>
> + case SO_MAX_DGRAM_QLEN:
> + sk->sk_max_ack_backlog = val;
> + break;
> +
Shouldn't the backlog be capped for unprivileged users to some configurable
value? I even think that max_dgram_qlen should be the upper bound.
I guess it is not that serious as socket read accounting does account all
packets which sit in the backlog queue.
Greetings,
Hannes
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] Per socket value for max datagram queue length
2014-01-22 15:20 ` Hannes Frederic Sowa
@ 2014-01-22 15:32 ` Hannes Frederic Sowa
0 siblings, 0 replies; 5+ messages in thread
From: Hannes Frederic Sowa @ 2014-01-22 15:32 UTC (permalink / raw)
To: Dan Ballard, Lennart Poettering, kay.sievers, Arnd Bergmann,
David S. Miller, Eric Dumazet, Eliezer Tamir, Neil Horman,
Li Zefan, linux-arch, linux-kernel, netdev
On Wed, Jan 22, 2014 at 04:20:36PM +0100, Hannes Frederic Sowa wrote:
> On Wed, Jan 22, 2014 at 07:11:20AM -0800, Dan Ballard wrote:
> > diff --git a/net/core/sock.c b/net/core/sock.c
> > index 5393b4b..1ff69d1 100644
> > --- a/net/core/sock.c
> > +++ b/net/core/sock.c
> > @@ -915,6 +915,10 @@ set_rcvbuf:
> > sk->sk_max_pacing_rate);
> > break;
> >
> > + case SO_MAX_DGRAM_QLEN:
> > + sk->sk_max_ack_backlog = val;
> > + break;
> > +
>
> Shouldn't the backlog be capped for unprivileged users to some configurable
> value? I even think that max_dgram_qlen should be the upper bound.
>
> I guess it is not that serious as socket read accounting does account all
> packets which sit in the backlog queue.
Just a follow-up:
sk_max_ack_backlog is also responsible for limiting the af_unix
dgram queues. Currently there is no socket accounting for the read
side of those unix dgram sockets. I tried to fix this once here,
http://patchwork.ozlabs.org/patch/231032/, but until that is done we
depend on max_dgram_qlen to limit those queues at all.
I hope I can get back to this patch anytime soon, as it solves the problem
that a bidirectional protocol ping-ponging with a dgram server socket
and not fetching its messages from the backlog queue can bring a server
to halt because it doesn't have any send space on the socket anymore.
Greetings,
Hannes
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] Per socket value for max datagram queue length
2014-01-22 15:11 [PATCH 1/1] Per socket value for max datagram queue length Dan Ballard
2014-01-22 15:20 ` Hannes Frederic Sowa
@ 2014-01-22 15:30 ` Eric Dumazet
2014-01-22 15:32 ` Daniel Borkmann
2 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2014-01-22 15:30 UTC (permalink / raw)
To: Dan Ballard
Cc: Lennart Poettering, kay.sievers, Arnd Bergmann, David S. Miller,
Eric Dumazet, Eliezer Tamir, Neil Horman, Li Zefan, linux-arch,
linux-kernel, netdev
On Wed, 2014-01-22 at 07:11 -0800, Dan Ballard wrote:
> Provides a new option for setsockopt SO_MAX_DGRAM_QLEN that sets and
> gets a socket specific max datagram queue length. Currently each socket
> has one but it's only ever initialized from
> /proc/sys/net/unix/max_dgram_qlen and then never adjustable later. Now
> each socket can have it individually tweaked during it's life.
>
Your patch suffers from many problems.
It breaks listen()
It doesn't compile on a lot of arches.
sk_max_ack_backlog is an unsigned short.
max_dgram_qlen is used, but only for Unix sockets at this time
Try : "git grep -n max_dgram_qlen" for details
> Signed-off-by: Dan Ballard <dan@mindstab.net>
> ---
> include/uapi/asm-generic/socket.h | 2 ++
> net/core/sock.c | 7 +++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/include/uapi/asm-generic/socket.h
> b/include/uapi/asm-generic/socket.h
> index 38f14d0..f8c3e6b 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -80,4 +80,6 @@
>
> #define SO_MAX_PACING_RATE 47
>
> +#define SO_MAX_DGRAM_QLEN 48
> +
> #endif /* __ASM_GENERIC_SOCKET_H */
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 5393b4b..1ff69d1 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -915,6 +915,10 @@ set_rcvbuf:
> sk->sk_max_pacing_rate);
> break;
>
> + case SO_MAX_DGRAM_QLEN:
> + sk->sk_max_ack_backlog = val;
> + break;
> +
> default:
> ret = -ENOPROTOOPT;
> break;
> @@ -1182,6 +1186,9 @@ int sock_getsockopt(struct socket *sock, int
> level, int optname,
> v.val = sk->sk_max_pacing_rate;
> break;
>
> + case SO_MAX_DGRAM_QLEN:
> + v.val = sk->sk_max_ack_backlog;
> + break;
> default:
> return -ENOPROTOOPT;
> }
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] Per socket value for max datagram queue length
2014-01-22 15:11 [PATCH 1/1] Per socket value for max datagram queue length Dan Ballard
2014-01-22 15:20 ` Hannes Frederic Sowa
2014-01-22 15:30 ` Eric Dumazet
@ 2014-01-22 15:32 ` Daniel Borkmann
2 siblings, 0 replies; 5+ messages in thread
From: Daniel Borkmann @ 2014-01-22 15:32 UTC (permalink / raw)
To: Dan Ballard
Cc: Lennart Poettering, kay.sievers, Arnd Bergmann, David S. Miller,
Eric Dumazet, Eliezer Tamir, Neil Horman, Li Zefan, linux-arch,
linux-kernel, netdev, Hannes Frederic Sowa
On 01/22/2014 04:11 PM, Dan Ballard wrote:
> Provides a new option for setsockopt SO_MAX_DGRAM_QLEN that sets and
> gets a socket specific max datagram queue length. Currently each socket
> has one but it's only ever initialized from
> /proc/sys/net/unix/max_dgram_qlen and then never adjustable later. Now
> each socket can have it individually tweaked during it's life.
>
> Signed-off-by: Dan Ballard <dan@mindstab.net>
> ---
> include/uapi/asm-generic/socket.h | 2 ++
> net/core/sock.c | 7 +++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> index 38f14d0..f8c3e6b 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -80,4 +80,6 @@
>
> #define SO_MAX_PACING_RATE 47
>
> +#define SO_MAX_DGRAM_QLEN 48
> +
This needs to be added in more than just asm-generic, e.g.
have a look at SO_MAX_PACING_RATE or SO_BPF_EXTENSIONS.
Also you might need to rebase to current net-next head and
maybe describe use cases more in-depth; next to what Hannes
just commented.
> #endif /* __ASM_GENERIC_SOCKET_H */
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 5393b4b..1ff69d1 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -915,6 +915,10 @@ set_rcvbuf:
> sk->sk_max_pacing_rate);
> break;
>
> + case SO_MAX_DGRAM_QLEN:
> + sk->sk_max_ack_backlog = val;
> + break;
> +
> default:
> ret = -ENOPROTOOPT;
> break;
> @@ -1182,6 +1186,9 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
> v.val = sk->sk_max_pacing_rate;
> break;
>
> + case SO_MAX_DGRAM_QLEN:
> + v.val = sk->sk_max_ack_backlog;
> + break;
> default:
> return -ENOPROTOOPT;
> }
^ permalink raw reply [flat|nested] 5+ messages in thread