There have been several instances where response from kernel
has overrun the stack buffer from the caller. Avoid future problems
by passing a size argument.
Also drop the unused peer and group arguments to rtnl_talk.
This work follows upon commit 6256f8c9e4 ("tc, bpf: finalize eBPF
support for cls and act front-end") and takes up the idea proposed by
Hannes Frederic Sowa to spawn a shell (or any other command) that holds
generated eBPF map file descriptors.
File descriptors, based on their id, are being fetched from the same
unix domain socket as demonstrated in the bpf_agent, the shell spawned
via execvpe(2) and the map fds passed over the environment, and thus
are made available to applications in the fashion of std{in,out,err}
for read/write access, for example in case of iproute2's examples/bpf/:
# env | grep BPF
BPF_NUM_MAPS=3
BPF_MAP1=6 <- BPF_MAP_ID_QUEUE (id 1)
BPF_MAP0=5 <- BPF_MAP_ID_PROTO (id 0)
BPF_MAP2=7 <- BPF_MAP_ID_DROPS (id 2)
# ls -la /proc/self/fd
[...]
lrwx------. 1 root root 64 Apr 14 16:46 0 -> /dev/pts/4
lrwx------. 1 root root 64 Apr 14 16:46 1 -> /dev/pts/4
lrwx------. 1 root root 64 Apr 14 16:46 2 -> /dev/pts/4
[...]
lrwx------. 1 root root 64 Apr 14 16:46 5 -> anon_inode:bpf-map
lrwx------. 1 root root 64 Apr 14 16:46 6 -> anon_inode:bpf-map
lrwx------. 1 root root 64 Apr 14 16:46 7 -> anon_inode:bpf-map
The advantage (as opposed to the direct/native usage) is that now the
shell is map fd owner and applications can terminate and easily reattach
to descriptors w/o any kernel changes. Moreover, multiple applications
can easily read/write eBPF maps simultaneously.
To further allow users for experimenting with that, next step is to add
a small helper that can get along with simple data types, so that also
shell scripts can make use of bpf syscall, f.e to read/write into maps.
Generally, this allows for prepopulating maps, or any runtime altering
which could influence eBPF program behaviour (f.e. different run-time
classifications, skb modifications, ...), dumping of statistics, etc.
Reference: http://thread.gmane.org/gmane.linux.network/357471/focus=357860
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Was broken by commit 288abf513f
Lets not be too clever and have a separate call to print flushed
actions info.
Broken looks like:
root@moja-1:~# tc actions add action drop index 4
root@moja-1:~# tc -s actions ls action gact
action order 0: gact action drop
random type none pass val 0
index 4 ref 1 bind 0 installed 9 sec used 4 sec
The fixed version looks like:
action order 0: gact action drop
random type none pass val 0
index 4 ref 1 bind 0 installed 9 sec used 4 sec
Sent 108948 bytes 1297 pkts (dropped 1297, overlimits 0)
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
This also fixes a long standing bug of not sanely reporting the
action chain ordering
Sample scenario test
on window 1(event window):
run "tc monitor" and observe events
on window 2:
sudo tc actions add action drop index 10
sudo tc actions add action ok index 12
sudo tc actions ls action gact
sudo tc actions flush action gact
See the event window reporting two entries
(doing another listing should show empty generic actions)
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
attached.
cheers,
jamal
commit 58d78f9f6447df324cdeb99262442c5e3f1f924b
Author: Jamal Hadi Salim <jhs@mojatatu.com>
Date: Sun Dec 22 10:34:18 2013 -0500
dont skip displaying of action chains or lists by TCA_ACT_MAX_PRIO
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Both rtnl_talk and rtnl_dump had a callback for handling portions
of netlink message that do not match the correct pid or seq.
But this callback was never used by any part of iproute2 so remove
it.
Fixes problems with xtables based MARK target ("ipt" module).
When tc loads the "ipt" (xt) module it kept the symbols local,
this made loading of libxtables not find the required struct.
currently ipt/xt is the only tc action module.
iproute2 never seem to do dlclose.
hopefully the modules doesn't export more symbols then needed.
In this situation hopefully the RTLD_GLOBAL flag won't hurt us.
I've been using this patch in the Debian package of iproute for
the last 3 weeks and noone has complained.
( This fixes http://bugs.debian.org/584898 )
Signed-off-by: Andreas Henriksson <andreas@fatal.se>
This will build the xt module (action ipt) of tc as a
shared object that is linked at runtime by tc if used,
rather then built into tc.
This is similar to how the atm qdisc support
is handled (q_atm.so).
Signed-off-by: Andreas Henriksson <andreas@xxxxxxxx>
User runs "tc monitor" (without quotes) and watches events of
addition, deletion and updates from qdiscs, classes, filters and
actions as they happen.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
