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  1. 18 2月, 2017 1 次提交
  3. 26 1月, 2017 1 次提交
    • J
      net sched actions: Add support for user cookies · 1045ba77
      由 Jamal Hadi Salim 提交于 
      Introduce optional 128-bit action cookie.
Like all other cookie schemes in the networking world (eg in protocols
like http or existing kernel fib protocol field, etc) the idea is to save
user state that when retrieved serves as a correlator. The kernel
_should not_ intepret it.  The user can store whatever they wish in the
128 bits.

Sample exercise(showing variable length use of cookie)

.. create an accept action with cookie a1b2c3d4
sudo $TC actions add action ok index 1 cookie a1b2c3d4

.. dump all gact actions..
sudo $TC -s actions ls action gact

    action order 0: gact action pass
     random type none pass val 0
     index 1 ref 1 bind 0 installed 5 sec used 5 sec
    Action statistics:
    Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
    backlog 0b 0p requeues 0
    cookie a1b2c3d4

.. bind the accept action to a filter..
sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \
u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 1

... send some traffic..
$ ping 127.0.0.1 -c 3
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.027 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.038 ms
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1045ba77
  5. 17 1月, 2017 1 次提交
    • D
      bpf: rework prog_digest into prog_tag · f1f7714e
      由 Daniel Borkmann 提交于 
      Commit 7bd509e3 ("bpf: add prog_digest and expose it via
fdinfo/netlink") was recently discussed, partially due to
admittedly suboptimal name of "prog_digest" in combination
with sha1 hash usage, thus inevitably and rightfully concerns
about its security in terms of collision resistance were
raised with regards to use-cases.

The intended use cases are for debugging resp. introspection
only for providing a stable "tag" over the instruction sequence
that both kernel and user space can calculate independently.
It's not usable at all for making a security relevant decision.
So collisions where two different instruction sequences generate
the same tag can happen, but ideally at a rather low rate. The
"tag" will be dumped in hex and is short enough to introspect
in tracepoints or kallsyms output along with other data such
as stack trace, etc. Thus, this patch performs a rename into
prog_tag and truncates the tag to a short output (64 bits) to
make it obvious it's not collision-free.

Should in future a hash or facility be needed with a security
relevant focus, then we can think about requirements, constraints,
etc that would fit to that situation. For now, rework the exposed
parts for the current use cases as long as nothing has been
released yet. Tested on x86_64 and s390x.

Fixes: 7bd509e3 ("bpf: add prog_digest and expose it via fdinfo/netlink")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f1f7714e
  7. 12 1月, 2017 1 次提交
  9. 09 1月, 2017 5 次提交
    • W
      net-tc: convert tc_from to tc_from_ingress and tc_redirected · bc31c905
      由 Willem de Bruijn 提交于 
      The tc_from field fulfills two roles. It encodes whether a packet was
redirected by an act_mirred device and, if so, whether act_mirred was
called on ingress or egress. Split it into separate fields.

The information is needed by the special IFB loop, where packets are
taken out of the normal path by act_mirred, forwarded to IFB, then
reinjected at their original location (ingress or egress) by IFB.

The IFB device cannot use skb->tc_at_ingress, because that may have
been overwritten as the packet travels from act_mirred to ifb_xmit,
when it passes through tc_classify on the IFB egress path. Cache this
value in skb->tc_from_ingress.

That field is valid only if a packet arriving at ifb_xmit came from
act_mirred. Other packets can be crafted to reach ifb_xmit. These
must be dropped. Set tc_redirected on redirection and drop all packets
that do not have this bit set.

Both fields are set only on cloned skbs in tc actions, so original
packet sources do not have to clear the bit when reusing packets
(notably, pktgen and octeon).
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bc31c905
    • W
      net-tc: convert tc_verd to integer bitfields · a5135bcf
      由 Willem de Bruijn 提交于 
      Extract the remaining two fields from tc_verd and remove the __u16
completely. TC_AT and TC_FROM are converted to equivalent two-bit
integer fields tc_at and tc_from. Where possible, use existing
helper skb_at_tc_ingress when reading tc_at. Introduce helper
skb_reset_tc to clear fields.

Not documenting tc_from and tc_at, because they will be replaced
with single bit fields in follow-on patches.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a5135bcf
    • W
      net-tc: extract skip classify bit from tc_verd · e7246e12
      由 Willem de Bruijn 提交于 
      Packets sent by the IFB device skip subsequent tc classification.
A single bit governs this state. Move it out of tc_verd in
anticipation of removing that __u16 completely.

The new bitfield tc_skip_classify temporarily uses one bit of a
hole, until tc_verd is removed completely in a follow-up patch.

Remove the bit hole comment. It could be 2, 3, 4 or 5 bits long.
With that many options, little value in documenting it.

Introduce a helper function to deduplicate the logic in the two
sites that check this bit.

The field tc_skip_classify is set only in IFB on skbs cloned in
act_mirred, so original packet sources do not have to clear the
bit when reusing packets (notably, pktgen and octeon).
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e7246e12
    • W
      net-tc: make MAX_RECLASSIFY_LOOP local · d6264071
      由 Willem de Bruijn 提交于 
      This field is no longer kept in tc_verd. Remove it from the global
definition of that struct.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d6264071
    • W
      net-tc: remove unused tc_verd fields · aec745e2
      由 Willem de Bruijn 提交于 
      Remove the last reference to tc_verd's munge and redirect ttl bits.
These fields are no longer used.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      aec745e2
  11. 09 12月, 2016 2 次提交
  13. 06 12月, 2016 1 次提交
    • D
      bpf: add prog_digest and expose it via fdinfo/netlink · 7bd509e3
      由 Daniel Borkmann 提交于 
      When loading a BPF program via bpf(2), calculate the digest over
the program's instruction stream and store it in struct bpf_prog's
digest member. This is done at a point in time before any instructions
are rewritten by the verifier. Any unstable map file descriptor
number part of the imm field will be zeroed for the hash.

fdinfo example output for progs:

  # cat /proc/1590/fdinfo/5
  pos:          0
  flags:        02000002
  mnt_id:       11
  prog_type:    1
  prog_jited:   1
  prog_digest:  b27e8b06da22707513aa97363dfb11c7c3675d28
  memlock:      4096

When programs are pinned and retrieved by an ELF loader, the loader
can check the program's digest through fdinfo and compare it against
one that was generated over the ELF file's program section to see
if the program needs to be reloaded. Furthermore, this can also be
exposed through other means such as netlink in case of a tc cls/act
dump (or xdp in future), but also through tracepoints or other
facilities to identify the program. Other than that, the digest can
also serve as a base name for the work in progress kallsyms support
of programs. The digest doesn't depend/select the crypto layer, since
we need to keep dependencies to a minimum. iproute2 will get support
for this facility.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7bd509e3
  15. 10 11月, 2016 1 次提交
  17. 04 11月, 2016 1 次提交
  19. 22 9月, 2016 1 次提交
  21. 16 9月, 2016 2 次提交
  23. 11 9月, 2016 1 次提交
    • A
      net/sched: cls_flower: Classify packet in ip tunnels · bc3103f1
      由 Amir Vadai 提交于 
      Introduce classifying by metadata extracted by the tunnel device.
Outer header fields - source/dest ip and tunnel id, are extracted from
the metadata when classifying.

For example, the following will add a filter on the ingress Qdisc of shared
vxlan device named 'vxlan0'. To forward packets with outer src ip
11.11.0.2, dst ip 11.11.0.1 and tunnel id 11. The packets will be
forwarded to tap device 'vnet0' (after metadata is released):

$ tc filter add dev vxlan0 protocol ip parent ffff: \
    flower \
      enc_src_ip 11.11.0.2 \
      enc_dst_ip 11.11.0.1 \
      enc_key_id 11 \
      dst_ip 11.11.11.1 \
    action tunnel_key release \
    action mirred egress redirect dev vnet0

The action tunnel_key, will be introduced in the next patch in this
series.
Signed-off-by: NAmir Vadai <amir@vadai.me>
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bc3103f1
  25. 19 8月, 2016 1 次提交
  27. 25 7月, 2016 2 次提交
  29. 08 6月, 2016 2 次提交
  31. 25 5月, 2016 1 次提交
  33. 17 5月, 2016 2 次提交
  35. 27 4月, 2016 1 次提交
  37. 11 3月, 2016 1 次提交
  39. 02 3月, 2016 1 次提交
    • J
      net: sched: cls_u32 add bit to specify software only rules · 9e8ce79c
      由 John Fastabend 提交于 
      In the initial implementation the only way to stop a rule from being
inserted into the hardware table was via the device feature flag.
However this doesn't work well when working on an end host system
where packets are expect to hit both the hardware and software
datapaths.

For example we can imagine a rule that will match an IP address and
increment a field. If we install this rule in both hardware and
software we may increment the field twice. To date we have only
added support for the drop action so we have been able to ignore
these cases. But as we extend the action support we will hit this
example plus more such cases. Arguably these are not even corner
cases in many working systems these cases will be common.

To avoid forcing the driver to always abort (i.e. the above example)
this patch adds a flag to add a rule in software only. A careful
user can use this flag to build software and hardware datapaths
that work together. One example we have found particularly useful
is to use hardware resources to set the skb->mark on the skb when
the match may be expensive to run in software but a mark lookup
in a hash table is cheap. The idea here is hardware can do in one
lookup what the u32 classifier may need to traverse multiple lists
and hash tables to compute. The flag is only passed down on inserts.
On deletion to avoid stale references in hardware we always try
to remove a rule if it exists.

The flags field is part of the classifier specific options. Although
it is tempting to lift this into the generic structure doing this
proves difficult do to how the tc netlink attributes are implemented
along with how the dump/change routines are called. There is also
precedence for putting seemingly generic pieces in the specific
classifier options such as TCA_U32_POLICE, TCA_U32_ACT, etc. So
although not ideal I've left FLAGS in the u32 options as well as it
simplifies the code greatly and user space has already learned how
to manage these bits ala 'tc' tool.

Another thing if trying to update a rule we require the flags to
be unchanged. This is to force user space, software u32 and
the hardware u32 to keep in sync. Thanks to Simon Horman for
catching this case.
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      9e8ce79c
  41. 18 9月, 2015 2 次提交
    • A
      bpf: add bpf_redirect() helper · 27b29f63
      由 Alexei Starovoitov 提交于 
      Existing bpf_clone_redirect() helper clones skb before redirecting
it to RX or TX of destination netdev.
Introduce bpf_redirect() helper that does that without cloning.

Benchmarked with two hosts using 10G ixgbe NICs.
One host is doing line rate pktgen.
Another host is configured as:
$ tc qdisc add dev $dev ingress
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section clone_redirect_xmit drop
so it receives the packet on $dev and immediately xmits it on $dev + 1
The section 'clone_redirect_xmit' in tcbpf1_kern.o file has the program
that does bpf_clone_redirect() and performance is 2.0 Mpps

$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section redirect_xmit drop
which is using bpf_redirect() - 2.4 Mpps

and using cls_bpf with integrated actions as:
$ tc filter add dev $dev root pref 10 \
  bpf run object-file tcbpf1_kern.o section redirect_xmit integ_act classid 1
performance is 2.5 Mpps

To summarize:
u32+act_bpf using clone_redirect - 2.0 Mpps
u32+act_bpf using redirect - 2.4 Mpps
cls_bpf using redirect - 2.5 Mpps

For comparison linux bridge in this setup is doing 2.1 Mpps
and ixgbe rx + drop in ip_rcv - 7.8 Mpps
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      27b29f63
    • D
      cls_bpf: introduce integrated actions · 045efa82
      由 Daniel Borkmann 提交于 
      Often cls_bpf classifier is used with single action drop attached.
Optimize this use case and let cls_bpf return both classid and action.
For backwards compatibility reasons enable this feature under
TCA_BPF_FLAG_ACT_DIRECT flag.

Then more interesting programs like the following are easier to write:
int cls_bpf_prog(struct __sk_buff *skb)
{
  /* classify arp, ip, ipv6 into different traffic classes
   * and drop all other packets
   */
  switch (skb->protocol) {
  case htons(ETH_P_ARP):
    skb->tc_classid = 1;
    break;
  case htons(ETH_P_IP):
    skb->tc_classid = 2;
    break;
  case htons(ETH_P_IPV6):
    skb->tc_classid = 3;
    break;
  default:
    return TC_ACT_SHOT;
  }

  return TC_ACT_OK;
}

Joint work with Daniel Borkmann.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      045efa82
  43. 22 5月, 2015 1 次提交
  45. 14 5月, 2015 2 次提交
  47. 05 5月, 2015 1 次提交
  49. 03 5月, 2015 1 次提交
  51. 02 3月, 2015 1 次提交
    • D
      cls_bpf: add initial eBPF support for programmable classifiers · e2e9b654
      由 Daniel Borkmann 提交于 
      This work extends the "classic" BPF programmable tc classifier by
extending its scope also to native eBPF code!

This allows for user space to implement own custom, 'safe' C like
classifiers (or whatever other frontend language LLVM et al may
provide in future), that can then be compiled with the LLVM eBPF
backend to an eBPF elf file. The result of this can be loaded into
the kernel via iproute2's tc. In the kernel, they can be JITed on
major archs and thus run in native performance.

Simple, minimal toy example to demonstrate the workflow:

  #include <linux/ip.h>
  #include <linux/if_ether.h>
  #include <linux/bpf.h>

  #include "tc_bpf_api.h"

  __section("classify")
  int cls_main(struct sk_buff *skb)
  {
    return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos));
  }

  char __license[] __section("license") = "GPL";

The classifier can then be compiled into eBPF opcodes and loaded
via tc, for example:

  clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o
  tc filter add dev em1 parent 1: bpf cls.o [...]

As it has been demonstrated, the scope can even reach up to a fully
fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c).

For tc, maps are allowed to be used, but from kernel context only,
in other words, eBPF code can keep state across filter invocations.
In future, we perhaps may reattach from a different application to
those maps e.g., to read out collected statistics/state.

Similarly as in socket filters, we may extend functionality for eBPF
classifiers over time depending on the use cases. For that purpose,
cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so
we can allow additional functions/accessors (e.g. an ABI compatible
offset translation to skb fields/metadata). For an initial cls_bpf
support, we allow the same set of helper functions as eBPF socket
filters, but we could diverge at some point in time w/o problem.

I was wondering whether cls_bpf and act_bpf could share C programs,
I can imagine that at some point, we introduce i) further common
handlers for both (or even beyond their scope), and/or if truly needed
ii) some restricted function space for each of them. Both can be
abstracted easily through struct bpf_verifier_ops in future.

The context of cls_bpf versus act_bpf is slightly different though:
a cls_bpf program will return a specific classid whereas act_bpf a
drop/non-drop return code, latter may also in future mangle skbs.
That said, we can surely have a "classify" and "action" section in
a single object file, or considered mentioned constraint add a
possibility of a shared section.

The workflow for getting native eBPF running from tc [1] is as
follows: for f_bpf, I've added a slightly modified ELF parser code
from Alexei's kernel sample, which reads out the LLVM compiled
object, sets up maps (and dynamically fixes up map fds) if any, and
loads the eBPF instructions all centrally through the bpf syscall.

The resulting fd from the loaded program itself is being passed down
to cls_bpf, which looks up struct bpf_prog from the fd store, and
holds reference, so that it stays available also after tc program
lifetime. On tc filter destruction, it will then drop its reference.

Moreover, I've also added the optional possibility to annotate an
eBPF filter with a name (e.g. path to object file, or something
else if preferred) so that when tc dumps currently installed filters,
some more context can be given to an admin for a given instance (as
opposed to just the file descriptor number).

Last but not least, bpf_prog_get() and bpf_prog_put() needed to be
exported, so that eBPF can be used from cls_bpf built as a module.
Thanks to 60a3b225 ("net: bpf: make eBPF interpreter images
read-only") I think this is of no concern since anything wanting to
alter eBPF opcode after verification stage would crash the kernel.

  [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpfSigned-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e2e9b654
  53. 30 10月, 2013 1 次提交
    • D
      net: sched: cls_bpf: add BPF-based classifier · 7d1d65cb
      由 Daniel Borkmann 提交于 
      This work contains a lightweight BPF-based traffic classifier that can
serve as a flexible alternative to ematch-based tree classification, i.e.
now that BPF filter engine can also be JITed in the kernel. Naturally, tc
actions and policies are supported as well with cls_bpf. Multiple BPF
programs/filter can be attached for a class, or they can just as well be
written within a single BPF program, that's really up to the user how he
wishes to run/optimize the code, e.g. also for inversion of verdicts etc.
The notion of a BPF program's return/exit codes is being kept as follows:

     0: No match
    -1: Select classid given in "tc filter ..." command
  else: flowid, overwrite the default one

As a minimal usage example with iproute2, we use a 3 band prio root qdisc
on a router with sfq each as leave, and assign ssh and icmp bpf-based
filters to band 1, http traffic to band 2 and the rest to band 3. For the
first two bands we load the bytecode from a file, in the 2nd we load it
inline as an example:

echo 1 > /proc/sys/net/core/bpf_jit_enable

tc qdisc del dev em1 root
tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

tc qdisc add dev em1 parent 1:1 sfq perturb 16
tc qdisc add dev em1 parent 1:2 sfq perturb 16
tc qdisc add dev em1 parent 1:3 sfq perturb 16

tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1
tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1
tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2
tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3

BPF programs can be easily created and passed to tc, either as inline
'bytecode' or 'bytecode-file'. There are a couple of front-ends that can
compile opcodes, for example:

1) People familiar with tcpdump-like filters:

   tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf

2) People that want to low-level program their filters or use BPF
   extensions that lack support by libpcap's compiler:

   bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf

   ssh.ops example code:
   ldh [12]
   jne #0x800, drop
   ldb [23]
   jneq #6, drop
   ldh [20]
   jset #0x1fff, drop
   ldxb 4 * ([14] & 0xf)
   ldh [%x + 14]
   jeq #0x16, pass
   ldh [%x + 16]
   jne #0x16, drop
   pass: ret #-1
   drop: ret #0

It was chosen to load bytecode into tc, since the reverse operation,
tc filter list dev em1, is then able to show the exact commands again.
Possible follow-up work could also include a small expression compiler
for iproute2. Tested with the help of bmon. This idea came up during
the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from
Eric Dumazet!
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7d1d65cb
  55. 13 10月, 2012 1 次提交
  57. 12 7月, 2012 1 次提交