[dpdk-dev] [PATCH v1 0/5] add framework to load and execute BPF code

[Konstantin Ananyev <konstantin.ananyev@intel.com>]

BPF is used quite intensively inside Linux (and BSD) kernels
for various different purposes and proved to be extremely useful.

BPF inside DPDK might also be used in a lot of places
for a lot of similar things.
 As an example to:
- packet filtering/tracing (aka tcpdump)
- packet classification
- statistics collection
- HW/PMD live-system debugging/prototyping - trace HW descriptors,
  internal PMD SW state, etc.
 ...

All of that in a dynamic, user-defined and extensible manner.

So these series introduce new library - librte_bpf.
librte_bpf provides API to load and execute BPF bytecode within
user-space dpdk app.
It supports basic set of features from eBPF spec.
Also it introduces basic framework to load/unload BPF-based filters
on eth devices (right now via SW RX/TX callbacks).

How to try it:
===============

1) run testpmd as usual and start your favorite forwarding case.
2) build bpf program you'd like to load
(you'll need clang v3.7 or above):
$ cd test/bpf
$ clang -O2 -target bpf -c t1.c

3) load bpf program(s):
testpmd> bpf-load rx|tx <portid> <queueid> <load-flags> <bpf-prog-filename>

<load-flags>:  [-][J][M]
J - use JIT generated native code, otherwise BPF interpreter will be used.
M - assume input parameter is a pointer to rte_mbuf,
    otherwise assume it is a pointer to first segment's data.

Few examples:

# to load (not JITed) dummy.o at TX queue 0, port 0:
testpmd> bpf-load tx 0 0 - ./dpdk.org/test/bpf/dummy.o

#to load (and JIT compile) t1.o at RX queue 0, port 1:
testpmd> bpf-load rx 1 0 J ./dpdk.org/test/bpf/t1.o

#to load and JIT t3.o (note that it expects mbuf as an input):
testpmd> bpf-load rx 2 0 JM ./dpdk.org/test/bpf/t3.o

If you are curious to check JIT generated native code:
gdb -p `pgrep testpmd`
(gdb) disas 0x7fd173c5f000,+76
Dump of assembler code from 0x7fd173c5f000 to 0x7fd173c5f04c:
   0x00007fd173c5f000:  mov    %rdi,%rsi
   0x00007fd173c5f003:  movzwq 0x10(%rsi),%rdi
   0x00007fd173c5f008:  mov    0x0(%rsi),%rdx
   0x00007fd173c5f00c:  add    %rdi,%rdx
   0x00007fd173c5f00f:  movzbq 0xc(%rdx),%rdi
   0x00007fd173c5f014:  movzbq 0xd(%rdx),%rdx
   0x00007fd173c5f019:  shl    $0x8,%rdx
   0x00007fd173c5f01d:  or     %rdi,%rdx
   0x00007fd173c5f020:  cmp    $0x608,%rdx
   0x00007fd173c5f027:  jne    0x7fd173c5f044
   0x00007fd173c5f029:  mov    $0xb712e8,%rdi
   0x00007fd173c5f030:  mov    0x0(%rdi),%rdi
   0x00007fd173c5f034:  mov    $0x40,%rdx
   0x00007fd173c5f03b:  mov    $0x4db2f0,%rax
   0x00007fd173c5f042:  callq  *%rax
   0x00007fd173c5f044:  mov    $0x1,%rax
   0x00007fd173c5f04b:  retq
End of assembler dump.

4) observe changed traffic behavior
Let say with the examples above:
  - dummy.o  does literally nothing, so no changes should be here,
    except some possible slowdown.
 - t1.o - should force to drop all packets that doesn't match:
   'dst 1.2.3.4 && udp && dst port 5000' filter.
 - t3.o - should dump to stdout ARP packets.

5) unload some or all bpf programs:
testpmd> bpf-unload tx 0 0

6) continue with step 3) or exit

TODO list:
==========
- meson build
- UT for it
- implement proper validate()
- allow JIT to generate bulk version
- FreeBSD support

Not currently supported features:
=================================
- cBPF
- tail-pointer call
- eBPF MAP
- JIT for non X86_64 targets
- skb

Konstantin Ananyev (5):
  bpf: add BPF loading and execution framework
  bpf: add JIT compilation for x86_64 ISA.
  bpf: introduce basic RX/TX BPF filters
  testpmd: new commands to load/unload BPF filters
  test: add few eBPF samples

 app/test-pmd/bpf_sup.h             |   25 +
 app/test-pmd/cmdline.c             |  146 ++++
 config/common_base                 |    5 +
 config/common_linuxapp             |    1 +
 lib/Makefile                       |    2 +
 lib/librte_bpf/Makefile            |   35 +
 lib/librte_bpf/bpf.c               |   52 ++
 lib/librte_bpf/bpf_exec.c          |  452 ++++++++++++
 lib/librte_bpf/bpf_impl.h          |   37 +
 lib/librte_bpf/bpf_jit_x86.c       | 1329 ++++++++++++++++++++++++++++++++++++
 lib/librte_bpf/bpf_load.c          |  380 +++++++++++
 lib/librte_bpf/bpf_pkt.c           |  524 ++++++++++++++
 lib/librte_bpf/bpf_validate.c      |   55 ++
 lib/librte_bpf/rte_bpf.h           |  158 +++++
 lib/librte_bpf/rte_bpf_ethdev.h    |   50 ++
 lib/librte_bpf/rte_bpf_version.map |   16 +
 mk/rte.app.mk                      |    2 +
 test/bpf/dummy.c                   |   20 +
 test/bpf/mbuf.h                    |  556 +++++++++++++++
 test/bpf/t1.c                      |   53 ++
 test/bpf/t2.c                      |   30 +
 test/bpf/t3.c                      |   36 +
 22 files changed, 3964 insertions(+)
 create mode 100644 app/test-pmd/bpf_sup.h
 create mode 100644 lib/librte_bpf/Makefile
 create mode 100644 lib/librte_bpf/bpf.c
 create mode 100644 lib/librte_bpf/bpf_exec.c
 create mode 100644 lib/librte_bpf/bpf_impl.h
 create mode 100644 lib/librte_bpf/bpf_jit_x86.c
 create mode 100644 lib/librte_bpf/bpf_load.c
 create mode 100644 lib/librte_bpf/bpf_pkt.c
 create mode 100644 lib/librte_bpf/bpf_validate.c
 create mode 100644 lib/librte_bpf/rte_bpf.h
 create mode 100644 lib/librte_bpf/rte_bpf_ethdev.h
 create mode 100644 lib/librte_bpf/rte_bpf_version.map
 create mode 100644 test/bpf/dummy.c
 create mode 100644 test/bpf/mbuf.h
 create mode 100644 test/bpf/t1.c
 create mode 100644 test/bpf/t2.c
 create mode 100644 test/bpf/t3.c

-- 
2.13.6