Merge branch 'Various BPF helper improvements'

Daniel Borkmann says:

====================
This series adds two BPF helpers, that is, one for retrieving the classid
of an skb and another one to redirect via the neigh subsystem, and improves
also the cookie helpers by removing the atomic counter. I've also added
the bpf_tail_call_static() helper to the libbpf API that we've been using
in Cilium for a while now, and last but not least the series adds a few
selftests. For details, please check individual patches, thanks!

v3 -> v4:
  - Removed out_rec error path (Martin)
  - Integrate BPF_F_NEIGH flag into rejecting invalid flags (Martin)
    - I think this way it's better to avoid bit overlaps given it's
      right in the place that would need to be extended on new flags
v2 -> v3:
  - Removed double skb->dev = dev assignment (David)
  - Added headroom check for v6 path (David)
  - Set set flowi4_proto for ip_route_output_flow (David)
  - Rebased onto latest bpf-next
v1 -> v2:
  - Rework cookie generator to support nested contexts (Eric)
  - Use ip_neigh_gw6() and container_of() (David)
  - Rename __throw_build_bug() and improve comments (Andrii)
  - Use bpf_tail_call_static() also in BPF samples (Maciej)
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2b1d3f16cbd1..1f17c6752deb 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3643,6 +3643,28 @@ union bpf_attr {
  *		*flags* are identical to those used for bpf_snprintf_btf.
  *	Return
  *		0 on success or a negative error in case of failure.
+ *
+ * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
+ * 	Description
+ * 		See **bpf_get_cgroup_classid**\ () for the main description.
+ * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
+ * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
+ * 		associated socket instead of the current process.
+ * 	Return
+ * 		The id is returned or 0 in case the id could not be retrieved.
+ *
+ * long bpf_redirect_neigh(u32 ifindex, u64 flags)
+ * 	Description
+ * 		Redirect the packet to another net device of index *ifindex*
+ * 		and fill in L2 addresses from neighboring subsystem. This helper
+ * 		is somewhat similar to **bpf_redirect**\ (), except that it
+ * 		fills in e.g. MAC addresses based on the L3 information from
+ * 		the packet. This helper is supported for IPv4 and IPv6 protocols.
+ * 		The *flags* argument is reserved and must be 0. The helper is
+ * 		currently only supported for tc BPF program types.
+ * 	Return
+ * 		The helper returns **TC_ACT_REDIRECT** on success or
+ * 		**TC_ACT_SHOT** on error.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3796,6 +3818,8 @@ union bpf_attr {
 	FN(copy_from_user),		\
 	FN(snprintf_btf),		\
 	FN(seq_printf_btf),		\
+	FN(skb_cgroup_classid),		\
+	FN(redirect_neigh),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper