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 <dan...@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.
*/
