Re: [dpdk-dev] [PATCH v6 0/9] add framework to load and execute BPF code

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/10/2018 11:23 AM, Konstantin Ananyev wrote:
> 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.
> - Comeup with your own idea
> 
> 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
> 
> 
> 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
> 
> Not currently supported features:
> =================================
> - cBPF
> - tail-pointer call
> - eBPF MAP
> - JIT for non X86_64 targets
> - skb
> - function calls for 32-bit apps
> - mbuf pointer as input parameter for 32-bit apps
> 
> v2:
>  - add meson build
>  - add freebsd build
>  - use new logging API
>  - using rte_malloc() for cbi allocation
>  - add extra logic into bpf_validate()
> 
> v3:
>  - add new test-case for it
>  - update docs
>  - update MAINTAINERS
> 
> v4:
>  - add more tests to cover BPF ISA
>  - fix few issues
> 
> v5:
>  - revert changes in tap_bpf.h
>  - rename eBPF related defines
>  - apply Thomas and Marco comments
> 
> v6:
>  Address Thomas, Kevin and Ferruh comments:
>  - handle case when libelf is not installed gracefully
>  - allow testpmd to be built without librte_bpf
>  - doc nits
> 
> Konstantin Ananyev (9):
>   bpf: add BPF loading and execution framework
>   bpf: add ability to load eBPF program from ELF object file
>   bpf: add more logic into bpf_validate>   bpf: add JIT compilation for x86_64 ISA
check-git-log.sh complains about "_"

>   bpf: introduce basic RX/TX BPF filters
s,RX/TX,Rx/Tx

>   testpmd: new commands to load/unload BPF filters
app/testpmd: ...

>   test: add few eBPF samples
>   test: introduce functional test for librte_bpf
>   doc: add bpf library related info

I confirm pathset passes from my build scripts.
Also new RTE_LIBRTE_BPF_ELF config option disabled by default resolves
dependency issue.