Currently, when eth_get_headlen calls flow dissector, it doesn't pass any
skb. Because we use passed skb to lookup associated networking namespace
to find whether we have a BPF program attached or not, we always use
C-based flow dissector in this case.
The goal of this patch series is to add new networking namespace argument
to the eth_get_headlen and make BPF flow dissector programs be able to
work in the skb-less case.
The series goes like this:
1. introduce a bunch of skb initialization helpers; those will be used to
initialize temporary skb
2. introduce skb_net which can be used to get networking namespace
associated with an skb
3. add new optional network namespace argument to __skb_flow_dissect and
plumb through the callers
4. prepare for new bpf flow dissector flavor, create some common routines
and do some renames
5. restrict access to a limited set of __sk_buff fields from flow
dissector programs
6. add new bpf_flow_dissect which uses temporary per-cpu skb and calls
BPF flow dissector program
7. convert flow dissector BPF_PROG_TEST_RUN to skb-less mode to show that
it works
8. add selftest that makes sure going over the packet bounds in
bpf_skb_load_bytes with shinfo-less skb doesn't cause any problems
9. add new net namespace argument to eth_get_headlen and convert the
callers
v2:
* moved temporary skb from stack into percpu (avoids memset of ~200 bytes
per packet)
* tightened down access to __sk_buff fields from flow dissector programs to
avoid touching shinfo (whitelist only relevant fields)
* addressed suggestions from Willem
Stanislav Fomichev (9):
net: introduce __init_skb{,_data,_shinfo} helpers
net: introduce skb_net helper
net: plumb network namespace into __skb_flow_dissect
net: flow_dissector: prepare for no-skb use case
flow_dissector: allow access only to a subset of __sk_buff fields
net: flow_dissector: handle no-skb use case
bpf: when doing BPF_PROG_TEST_RUN for flow dissector use no-skb mode
selftests/bpf: add flow dissector bpf_skb_load_bytes helper test
net: flow_dissector: pass net argument to the eth_get_headlen
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +-
drivers/net/ethernet/hisilicon/hns/hns_enet.c | 3 +-
.../net/ethernet/hisilicon/hns3/hns3_enet.c | 3 +-
drivers/net/ethernet/intel/fm10k/fm10k_main.c | 2 +-
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 3 +-
drivers/net/ethernet/intel/iavf/iavf_txrx.c | 2 +-
drivers/net/ethernet/intel/ice/ice_txrx.c | 2 +-
drivers/net/ethernet/intel/igb/igb_main.c | 2 +-
drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 2 +-
.../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 3 +-
.../net/ethernet/mellanox/mlx5/core/en_tx.c | 3 +-
drivers/net/tun.c | 3 +-
include/linux/etherdevice.h | 2 +-
include/linux/skbuff.h | 48 +++++--
net/bpf/test_run.c | 48 ++-----
net/core/filter.c | 13 +-
net/core/flow_dissector.c | 135 +++++++++++++-----
net/core/skbuff.c | 76 +++++-----
net/ethernet/eth.c | 8 +-
.../prog_tests/flow_dissector_load_bytes.c | 50 +++++++
21 files changed, 269 insertions(+), 143 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/flow_dissector_load_bytes.c
--
2.21.0.225.g810b269d1ac-goog
