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 __init_skb and __init_skb_shinfo; 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. add new __flow_bpf_dissect which constructs temporary on-stack skb (using __init_skb) and calls BPF flow dissector program 5. convert flow dissector BPF_PROG_TEST_RUN to skb-less mode to show that it works 6. add selftest that makes sure going over the packet bounds in bpf_skb_load_bytes with on-stack skb doesn't cause any problems 7. add new net namespace argument go eth_get_headlen and convert the callers Stanislav Fomichev (7): net: introduce __init_skb and __init_skb_shinfo helpers net: introduce skb_net helper net: plumb network namespace into __skb_flow_dissect 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 | 23 +++- net/bpf/test_run.c | 52 +++------ net/core/flow_dissector.c | 105 +++++++++++++----- net/core/skbuff.c | 78 +++++++------ net/ethernet/eth.c | 8 +- tools/testing/selftests/bpf/test_progs.c | 49 ++++++++ 20 files changed, 227 insertions(+), 122 deletions(-) -- 2.20.1.611.gfbb209baf1-goog
