2aad32613c
Stanislav Fomichev says: ==================== 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: * use new kernel context (struct bpf_flow_dissector) for flow dissector programs; this makes it easy to distinguish between skb and no-skb case and supports calling BPF flow dissector on a chunk of raw data * convert BPF_PROG_TEST_RUN to use raw data * plumb network namespace into __skb_flow_dissect from all callers * handle no-skb case in __skb_flow_dissect * update eth_get_headlen to include net namespace argument and convert all existing users * add selftest to make sure bpf_skb_load_bytes is not allowed in the no-skb mode * extend test_progs to exercise skb-less flow dissection as well * stop adjusting nhoff/thoff by ETH_HLEN in BPF_PROG_TEST_RUN v6: * more suggestions by Alexei: * eth_get_headlen now takes net dev, not net namespace * test skb-less case via tun eth_get_headlen * fix return errors in bpf_flow_load * don't adjust nhoff/thoff by ETH_HLEN v5: * API changes have been submitted via bpf/stable tree v4: * prohibit access to vlan fields as well (otherwise, inconsistent between skb/skb-less cases) * drop extra unneeded check for skb->vlan_present in bpf_flow.c v3: * new kernel xdp_buff-like context per Alexei suggestion * drop skb_net helper * properly clamp flow_keys->nhoff 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 ==================== Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.