Re: [dpdk-dev] [RFC PATCH 5/5] test: add few eBPF samples

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

> >
> > Add few simple eBPF programs as an example.
> >
> > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > diff --git a/test/bpf/mbuf.h b/test/bpf/mbuf.h
> > new file mode 100644
> > index 000000000..aeef6339d
> > --- /dev/null
> > +++ b/test/bpf/mbuf.h
> > @@ -0,0 +1,556 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2010-2014 Intel Corporation.
> > + * Copyright 2014 6WIND S.A.
> > + */
> > +
> > +/*
> > + * Snipper from dpdk.org rte_mbuf.h.
> > + * used to provide BPF programs information about rte_mbuf layout.
> > + */
> > +
> > +#ifndef _MBUF_H_
> > +#define _MBUF_H_
> > +
> > +#include <stdint.h>
> > +#include <rte_common.h>
> > +#include <rte_memory.h>
> 
> Is it worth to keep an copy of mbuf for standalone purpose?
> Since clang is already supported, I think, if someone need mbuf then
> they can include DPDK headers. Just thinking in maintainability
> perspective.

That would be ideal.
I made a snippet just to avoid compiler errors for bpf target.
Will try to address it in next version.

> 
> > diff --git a/test/bpf/t1.c b/test/bpf/t1.c
> > new file mode 100644
> > index 000000000..e587d5e5b
> > --- /dev/null
> > +++ b/test/bpf/t1.c
> > @@ -0,0 +1,54 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2018 Intel Corporation
> > + */
> > +
> > +/*
> > + * eBPF program sample.
> > + * Accepts pointer to first segment packet data as an input parameter.
> > + * analog of tcpdump -s 1 -d 'dst 1.2.3.4 && udp && dst port 5000'
> > + * (000) ldh      [12]
> > + * (001) jeq      #0x800           jt 2    jf 12
> > + * (002) ld       [30]
> > + * (003) jeq      #0x1020304       jt 4    jf 12
> > + * (004) ldb      [23]
> > + * (005) jeq      #0x11            jt 6    jf 12
> > + * (006) ldh      [20]
> > + * (007) jset     #0x1fff          jt 12   jf 8
> > + * (008) ldxb     4*([14]&0xf)
> > + * (009) ldh      [x + 16]
> > + * (010) jeq      #0x1388          jt 11   jf 12
> > + * (011) ret      #1
> > + * (012) ret      #0
> > + *
> > + * To compile:
> > + * clang -O2 -DRTE_CACHE_LINE_SIZE=64 -I${RTE_SDK}/${RTE_TARGET}/include \
> 
> Does not look like, this application is accessing any DPDK stuff, If so,
> Should we remove -DRTE_CACHE_LINE_SIZE=64 -I${RTE_SDK}/${RTE_TARGET}/include?

Yes, will do.

> 
> > + * -target bpf -c t1.c
> > + */
> > +
> > +#include <stdint.h>
> > +#include <net/ethernet.h>
> > +#include <netinet/ip.h>
> > +#include <netinet/udp.h>
> > +
> > +uint64_t
> > +entry(void *pkt)
> > +{
> > +	struct ether_header *ether_header = (void *)pkt;
> > +
> > +	if (ether_header->ether_type != __builtin_bswap16(0x0800))
> > +		return 0;
> > +
> > +	struct iphdr *iphdr = (void *)(ether_header + 1);
> > +	if (iphdr->protocol != 17 || (iphdr->frag_off & 0x1ffff) != 0 ||
> > +			iphdr->daddr != __builtin_bswap32(0x1020304))
> > +		return 0;
> > +
> > +	int hlen = iphdr->ihl * 4;
> > +	struct udphdr *udphdr = (void *)iphdr + hlen;
> > +
> > +	if (udphdr->dest !=  __builtin_bswap16(5000))
> > +		return 0;
> > +
> > +	return 1;
> > +}
> > +
> > diff --git a/test/bpf/t2.c b/test/bpf/t2.c
> > new file mode 100644
> > index 000000000..6228609c5
> > --- /dev/null
> > +++ b/test/bpf/t2.c
> > @@ -0,0 +1,31 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2018 Intel Corporation
> > + */
> > +
> > +/*
> > + * eBPF program sample.
> > + * Accepts pointer to struct rte_mbuf as an input parameter.
> > + * cleanup mbuf's vlan_tci and all related RX flags
> > + * (PKT_RX_VLAN_PKT | PKT_RX_VLAN_STRIPPED).
> > + * Doesn't touch contents of packet data.
> > + * To compile:
> > + * clang -O2 -DRTE_CACHE_LINE_SIZE=... -I${RTE_SDK}/${RTE_TARGET}/include \
> > + * -target bpf -Wno-int-to-void-pointer-cast -c t2.c
> > + */
> > +
> > +#include <stdint.h>
> > +#include <stddef.h>
> > +#include "mbuf.h"
> 
> Can we take Cache line size from rte_config.h which anyway included in
> mbuf.h through rte_memory.h?

Makes sense, will update in v2.
Konstantin