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From: Daniel Borkmann <daniel@iogearbox•net>
To: Daniel Mack <daniel@zonque•org>, htejun@fb•com, ast@fb•com
Cc: davem@davemloft•net, kafai@fb•com, fw@strlen•de,
	pablo@netfilter•org, harald@redhat•com, netdev@vger•kernel.org,
	sargun@sargun•me
Subject: Re: [PATCH v3 5/6] net: core: run cgroup eBPF egress programs
Date: Tue, 30 Aug 2016 00:03:23 +0200	[thread overview]
Message-ID: <57C4B12B.2070302@iogearbox.net> (raw)
In-Reply-To: <1472241532-11682-6-git-send-email-daniel@zonque.org>

On 08/26/2016 09:58 PM, Daniel Mack wrote:
> If the cgroup associated with the receiving socket has an eBPF
> programs installed, run them from __dev_queue_xmit().
>
> eBPF programs used in this context are expected to either return 1 to
> let the packet pass, or != 1 to drop them. The programs have access to
> the full skb, including the MAC headers.
>
> Note that cgroup_bpf_run_filter() is stubbed out as static inline nop
> for !CONFIG_CGROUP_BPF, and is otherwise guarded by a static key if
> the feature is unused.
>
> Signed-off-by: Daniel Mack <daniel@zonque•org>
> ---
>   net/core/dev.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index a75df86..17484e6 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -141,6 +141,7 @@
>   #include <linux/netfilter_ingress.h>
>   #include <linux/sctp.h>
>   #include <linux/crash_dump.h>
> +#include <linux/bpf-cgroup.h>
>
>   #include "net-sysfs.h"
>
> @@ -3329,6 +3330,11 @@ static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
>   	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP))
>   		__skb_tstamp_tx(skb, NULL, skb->sk, SCM_TSTAMP_SCHED);
>
> +	rc = cgroup_bpf_run_filter(skb->sk, skb,
> +				   BPF_ATTACH_TYPE_CGROUP_INET_EGRESS);
> +	if (rc)
> +		return rc;

This would leak the whole skb by the way.

Apart from that, could this be modeled w/o affecting the forwarding path (at some
local output point where we know to have a valid socket)? Then you could also drop
the !sk and sk->sk_family tests, and we wouldn't need to replicate parts of what
clsact is doing as well. Hmm, maybe access to src/dst mac could be handled to be
just zeroes since not available at that point?

>   	/* Disable soft irqs for various locks below. Also
>   	 * stops preemption for RCU.
>   	 */
>

  reply	other threads:[~2016-08-29 22:03 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-26 19:58 [PATCH v3 0/6] Add eBPF hooks for cgroups Daniel Mack
2016-08-26 19:58 ` [PATCH v3 1/6] bpf: add new prog type for cgroup socket filtering Daniel Mack
2016-08-29 22:14   ` Daniel Borkmann
2016-09-05 12:48     ` Daniel Mack
2016-08-26 19:58 ` [PATCH v3 2/6] cgroup: add support for eBPF programs Daniel Mack
2016-08-27  0:03   ` Alexei Starovoitov
2016-09-05 12:47     ` Daniel Mack
2016-08-29 22:42   ` Daniel Borkmann
2016-09-05 12:50     ` Daniel Mack
2016-08-29 23:04   ` Sargun Dhillon
2016-09-05 14:49     ` Daniel Mack
2016-09-05 21:40       ` Sargun Dhillon
2016-09-05 22:39         ` Alexei Starovoitov
2016-08-26 19:58 ` [PATCH v3 3/6] bpf: add BPF_PROG_ATTACH and BPF_PROG_DETACH commands Daniel Mack
2016-08-27  0:08   ` Alexei Starovoitov
2016-09-05 12:56     ` Daniel Mack
2016-09-05 15:30       ` David Laight
2016-09-05 15:40         ` Daniel Mack
2016-09-05 17:29       ` Joe Perches
2016-08-29 23:00   ` Daniel Borkmann
2016-09-05 12:54     ` Daniel Mack
2016-09-05 13:56       ` Daniel Borkmann
2016-09-05 14:09         ` Daniel Mack
2016-09-05 17:09           ` Daniel Borkmann
2016-09-05 18:32             ` Alexei Starovoitov
2016-09-05 18:43               ` Daniel Mack
2016-08-26 19:58 ` [PATCH v3 4/6] net: filter: run cgroup eBPF ingress programs Daniel Mack
2016-08-29 23:15   ` Daniel Borkmann
2016-08-26 19:58 ` [PATCH v3 5/6] net: core: run cgroup eBPF egress programs Daniel Mack
2016-08-29 22:03   ` Daniel Borkmann [this message]
2016-08-29 22:23     ` Sargun Dhillon
2016-09-05 14:22     ` Daniel Mack
2016-09-06 17:14       ` Daniel Borkmann
2016-08-26 19:58 ` [PATCH v3 6/6] samples: bpf: add userspace example for attaching eBPF programs to cgroups Daniel Mack
2016-08-27 13:00 ` [PATCH v3 0/6] Add eBPF hooks for cgroups Rami Rosen

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