On Tue, 8 Oct, 2019, 9:31 AM Stephen Hemminger, <[email protected]> wrote:
> On Tue, 8 Oct 2019 09:17:08 +0530 > Jerin Jacob <[email protected]> wrote: > > > On Tue, 8 Oct, 2019, 3:15 AM Stephen Hemminger, < > [email protected]> > > wrote: > > > > > On Tue, 8 Oct 2019 01:03:17 +0530 > > > Jerin Jacob <[email protected]> wrote: > > > > > > > On Mon, 7 Oct, 2019, 11:03 PM Stephen Hemminger, < > > > [email protected]> > > > > wrote: > > > > > > > > > On Mon, 7 Oct 2019 22:37:43 +0530 > > > > > Jerin Jacob <[email protected]> wrote: > > > > > > > > > > > On Mon, 7 Oct, 2019, 10:23 PM Stephen Hemminger, < > > > > > [email protected]> > > > > > > wrote: > > > > > > > > > > > > > Simple classic BPF interpreter based off of libpcap. > > > > > > > > > > > > > > This is a copy of the BPF interpreter from libpcap which is > > > > > > > modified to handle mbuf meta data. The existing > pcap_offline_filter > > > > > > > does not expose a way to match VLAN tags. Copying the BPF > > > interpreter > > > > > > > also means that rte_pdump still does not have a hard dependency > > > > > > > on libpcap. > > > > > > > > > > > > > > > > > > > Why not use DPDK's librte_bpf library? Rather implementing cBPF > > > > > > interpreter. Currently it supports eBPF which is super set of > > > cBPF.if is > > > > > > this features very specific to cBPF, we clould simply implement > > > cBPF > > > > > using > > > > > > eBPF or implement a new cBPF program type. That scheme could > leverage > > > > > > existing JIT infrastructure also. Using JIT will improve > filtering > > > > > > performance. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Because pcap library generates cBPF in its string to BPF compiler. > > > > > Translating cBPF to eBPF is non trivial. > > > > > > > > > > > > > Then at least cBPF interpreter should move to librte_bpf. We can > hook to > > > > JIT if required in future. > > > > > > The opcodes for cBPF and eBPF are not compatiable. > > > > > > > Yeah. I am saying to add new program type in bpf library of cBPF. > Obviously > > pdump is not the correct place for cBPF interpreter. Moving to rte_libbpf > > library would help to enable other applications or libraries to use cBPF > > bpf program class. > > The problem is you need a version of string to BPF program which is what > the libpcap pcap_compile() function does for you. eBPF as used now is all > about having a full language (CLANG or GCC) and that is not what is needed > here at all. The problem is not the interpreter, the problem is on the > userspace BPF side. Until/unless that is fixed, cBPF is a better solution. > I am not saying to use eBPF with libpcap. All I am saying to move the cBPF interpreter code(this patch) to rte_libbpf as it is the correct place of that code in DPDK PoV. So that it can be used by another applications or library. >
