[PATCH bpf-next 00/10] introduction of bpf_xdp_adjust_tail

Nikita V. Shirokov
2018-04-17T06:51:42Z

In this patch series i'm adding new bpf helper which allow to manupulate
xdp's data_end pointer. right now only "shrinking" (reduce packet's size
by moving pointer) is supported (and i see no use case for "growing").
Main use case for such helper is to be able to generate controll (ICMP)
messages from XDP context. such messages usually contains first N bytes
from original packets as a payload, and this is exactly what this helper
would allow us to do (see patch 3 for sample program, where we generate
ICMP "packet too big" message). This helper could be usefull for load
balancing applications where after additional encapsulation, resulting
packet could be bigger then interface MTU.
Aside from new helper this patch series contains minor changes in device
drivers (for ones which requires), so they would recal packet's length
not only when head pointer was adjusted, but if tail's one as well.

Nikita V. Shirokov (10):
[bpf]: adding bpf_xdp_adjust_tail helper
[bpf]: adding tests for bpf_xdp_adjust_tail
[bpf]: add bpf_xdp_adjust_tail sample prog
[bpf]: make generic xdp compatible w/ bpf_xdp_adjust_tail
[bpf]: make mlx4 compatible w/ bpf_xdp_adjust_tail
[bpf]: make bnxt compatible w/ bpf_xdp_adjust_tail
[bpf]: make cavium thunder compatible w/ bpf_xdp_adjust_tail
[bpf]: make netronome nfp compatible w/ bpf_xdp_adjust_tail
[bpf]: make tun compatible w/ bpf_xdp_adjust_tail
[bpf]: make virtio compatible w/ bpf_xdp_adjust_tail

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 2 +-
drivers/net/ethernet/cavium/thunder/nicvf_main.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
.../net/ethernet/netronome/nfp/nfp_net_common.c | 2 +-
drivers/net/tun.c | 3 +-
drivers/net/virtio_net.c | 7 +-
include/uapi/linux/bpf.h | 10 +-
net/bpf/test_run.c | 3 +-
net/core/dev.c | 10 +-
net/core/filter.c | 29 +++-
samples/bpf/Makefile | 4 +
samples/bpf/xdp_adjust_tail_kern.c | 151 +++++++++++++++++++++
samples/bpf/xdp_adjust_tail_user.c | 141 +++++++++++++++++++
tools/include/uapi/linux/bpf.h | 11 +-
tools/testing/selftests/bpf/Makefile | 2 +-
tools/testing/selftests/bpf/bpf_helpers.h | 5 +
tools/testing/selftests/bpf/test_adjust_tail.c | 29 ++++
tools/testing/selftests/bpf/test_progs.c | 32 +++++
18 files changed, 433 insertions(+), 12 deletions(-)
create mode 100644 samples/bpf/xdp_adjust_tail_kern.c
create mode 100644 samples/bpf/xdp_adjust_tail_user.c
create mode 100644 tools/testing/selftests/bpf/test_adjust_tail.c

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2.15.1