Re: [dpdk-dev] [RFC PATCH 0/2] using scapy to generate packet templates

["Van Haaren, Harry" <harry.van.haaren@intel.com>]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Xueming Li
> Sent: Thursday, October 19, 2017 3:07 PM
> To: Wu, Jingjing <jingjing.wu@intel.com>
> Cc: Xueming Li <xuemingl@mellanox.com>; dev@dpdk.org
> Subject: [dpdk-dev] [RFC PATCH 0/2] using scapy to generate packet templates

Hi,

First off - cool to make DPDK more dynamic with Scapy, and I see value in
"somehow" enabling DPDK with Scapy.

> The target is to make testpmd flexible to generate all kinds of packet
> in just one line. Examples:
> 
> # send UDP packet to port 0 queue 0
> testpmd> scapy 0 Ether()/IP()/UDP()/"hello_world"
> 
> # send 4 L3 VXLAN packets with inner UDP dport 1-4 to port 1 queue 1-4, one
> packet per queue
> testpmd> scapy 1 Ether()/IP()/UDP()/VXLAN()/IPv6()/UDP(dport=(1,4))/"cool"
> 
> # Random
> testpmd> scapy 2
> Ether(src=RandMAC())/IP(dst=RandIP())/TCP(sport=RandShort(),dport=0x1234)
> 
> This patch introduce scapy - a python tool to generate static packet
> templates.
> Txonly forwarding mode is modified to support template if available.


Testpmd is a good use-case, but perhaps we're limiting the scope of DPDK/Scapy
if we only integrate with Testpmd. What if I wanted to easily generate some traffic from a sample app?

As a suggestion, what about building a library that provides Scapy functionality,
allowing any application to easily generate mbufs using the rte_scapy* functions:

/* demo usage */
rte_scapy *scapy = rte_scapy_init();
rte_mbuf *m = rte_scapy_mbuf_from_str(scapy, "Ether()/IP()/UDP()");


Testpmd could then use the rte_scapy library, passing in any parameters
after   testpmd> scapy   command as a string?

Had you already considered this library type design?


> Two new configuration:
> CONFIG_RTE_TEST_PMD_SCAPY=y
> CONFIG_RTE_PYTHON=python2.7
> 
> Scapy quick demo: http://www.secdev.org/projects/scapy/demo.html
> 
> There are 2 other potential solution to support more fancy sending in the
> future:
> 1. Invoke scapy and expose mbuf hugepage pointers to python
>    This should allow more flexible and dynamic processing
> 2. Scapy uses wrapped DPDK port as regular port
>    Make scapy capable to send high speed streams.

Not a strong opinion, but a gut feeling;
I see more value in generating packets with Python and using them from C
than giving Python full access to DPDK internals and hugepages.

Regards, -Harry


> Xueming Li (2):
>   app/testpmd: add packet template
>   app/testpmd: add scapy command as pkt template
> 
>  app/test-pmd/Makefile  |  5 +++
>  app/test-pmd/cmdline.c | 99
> +++++++++++++++++++++++++++++++++++++++++++++++++-
>  app/test-pmd/testpmd.c |  3 ++
>  app/test-pmd/testpmd.h |  1 +
>  app/test-pmd/txonly.c  | 42 +++++++++++++--------
>  config/common_base     |  2 +
>  6 files changed, 135 insertions(+), 17 deletions(-)
> 
> --
> 2.13.3