Merge branch 'enable-bpf_skc-cast-for-networking-progs'

Martin KaFai Lau says:

====================
This set allows networking prog type to directly read fields from
the in-kernel socket type, e.g. "struct tcp_sock".

Patch 2 has the details on the use case.

v3:
- Pass arg_btf_id instead of fn into check_reg_type() in Patch 1 (Lorenz)
- Move arg_btf_id from func_proto to struct bpf_reg_types in Patch 2 (Lorenz)
- Remove test_sock_fields from .gitignore in Patch 8 (Andrii)
- Add tests to have better coverage on the modified helpers (Alexei)
  Patch 13 is added.
- Use "void *sk" as the helper argument in UAPI bpf.h

v3:
- ARG_PTR_TO_SOCK_COMMON_OR_NULL was attempted in v2.  The _OR_NULL was
  needed because the PTR_TO_BTF_ID could be NULL but note that a could be NULL
  PTR_TO_BTF_ID is not a scalar NULL to the verifier.  "_OR_NULL" implicitly
  gives an expectation that the helper can take a scalar NULL which does
  not make sense in most (except one) helpers.  Passing scalar NULL
  should be rejected at the verification time.

  Thus, this patch uses ARG_PTR_TO_BTF_ID_SOCK_COMMON to specify that the
  helper can take both the btf-id ptr or the legacy PTR_TO_SOCK_COMMON but
  not scalar NULL.  It requires the func_proto to explicitly specify the
  arg_btf_id such that there is a very clear expectation that the helper
  can handle a NULL PTR_TO_BTF_ID.

v2:
- Add ARG_PTR_TO_SOCK_COMMON_OR_NULL (Lorenz)
====================

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

1 files changed, 8 insertions, 7 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a22812561064..2d6519a2ed77 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2512,7 +2512,7 @@ union bpf_attr {
  *		result is from *reuse*\ **->socks**\ [] using the hash of the
  *		tuple.
  *
- * long bpf_sk_release(struct bpf_sock *sock)
+ * long bpf_sk_release(void *sock)
  *	Description
  *		Release the reference held by *sock*. *sock* must be a
  *		non-**NULL** pointer that was returned from
@@ -2692,7 +2692,7 @@ union bpf_attr {
  *		result is from *reuse*\ **->socks**\ [] using the hash of the
  *		tuple.
  *
- * long bpf_tcp_check_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
+ * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
  * 	Description
  * 		Check whether *iph* and *th* contain a valid SYN cookie ACK for
  * 		the listening socket in *sk*.
@@ -2861,6 +2861,7 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf-local-storage cannot be found.
+ *		**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
  *
  * long bpf_send_signal(u32 sig)
  *	Description
@@ -2877,7 +2878,7 @@ union bpf_attr {
  *
  *		**-EAGAIN** if bpf program can try again.
  *
- * s64 bpf_tcp_gen_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
+ * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
  *	Description
  *		Try to issue a SYN cookie for the packet with corresponding
  *		IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
@@ -3106,7 +3107,7 @@ union bpf_attr {
  * 	Return
  * 		The id is returned or 0 in case the id could not be retrieved.
  *
- * long bpf_sk_assign(struct sk_buff *skb, struct bpf_sock *sk, u64 flags)
+ * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
  *	Description
  *		Helper is overloaded depending on BPF program type. This
  *		description applies to **BPF_PROG_TYPE_SCHED_CLS** and
@@ -3234,11 +3235,11 @@ union bpf_attr {
  *
  *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
  *
- * u64 bpf_sk_cgroup_id(struct bpf_sock *sk)
+ * u64 bpf_sk_cgroup_id(void *sk)
  *	Description
  *		Return the cgroup v2 id of the socket *sk*.
  *
- *		*sk* must be a non-**NULL** pointer to a full socket, e.g. one
+ *		*sk* must be a non-**NULL** pointer to a socket, e.g. one
  *		returned from **bpf_sk_lookup_xxx**\ (),
  *		**bpf_sk_fullsock**\ (), etc. The format of returned id is
  *		same as in **bpf_skb_cgroup_id**\ ().
@@ -3248,7 +3249,7 @@ union bpf_attr {
  *	Return
  *		The id is returned or 0 in case the id could not be retrieved.
  *
- * u64 bpf_sk_ancestor_cgroup_id(struct bpf_sock *sk, int ancestor_level)
+ * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
  *	Description
  *		Return id of cgroup v2 that is ancestor of cgroup associated
  *		with the *sk* at the *ancestor_level*.  The root cgroup is at