[PATCH v2 bpf-next 0/3] Auto-generate list of BPF helpers

[PATCH v2 bpf-next 0/3] Auto-generate list of BPF helpers

[Andrii Nakryiko]

This patch set adds ability to auto-generate list of BPF helper definitions.
It relies on existing scripts/bpf_helpers_doc.py and include/uapi/linux/bpf.h
having a well-defined set of comments. bpf_helper_defs.h contains all BPF
helper signatures which stay in sync with latest bpf.h UAPI. This
auto-generated header is included from bpf_helpers.h, while all previously
hand-written BPF helper definitions are simultaneously removed in patch #3.
The end result is less manually maintained and redundant boilerplate code,
while also more consistent and well-documented set of BPF helpers. Generated
helper definitions are completely independent from a specific bpf.h on
a target system, because it doesn't use BPF_FUNC_xxx enums.

v1->v2:
- add bpf_helper_defs.h to .gitignore and `make clean` (Alexei);

Andrii Nakryiko (3):
  uapi/bpf: fix helper docs
  scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions
  libbpf: auto-generate list of BPF helper definitions

 include/uapi/linux/bpf.h       |  32 ++--
 scripts/bpf_helpers_doc.py     | 155 ++++++++++++++++++-
 tools/include/uapi/linux/bpf.h |  32 ++--
 tools/lib/bpf/.gitignore       |   1 +
 tools/lib/bpf/Makefile         |  10 +-
 tools/lib/bpf/bpf_helpers.h    | 264 +--------------------------------
 6 files changed, 196 insertions(+), 298 deletions(-)

-- 
2.17.1

[PATCH v2 bpf-next 1/3] uapi/bpf: fix helper docs

[Andrii Nakryiko]

Various small fixes to BPF helper documentation comments, enabling
automatic header generation with a list of BPF helpers.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 include/uapi/linux/bpf.h       | 32 ++++++++++++++++----------------
 tools/include/uapi/linux/bpf.h | 32 ++++++++++++++++----------------
 2 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 77c6be96d676..a65c3b0c6935 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -794,7 +794,7 @@ union bpf_attr {
  * 		A 64-bit integer containing the current GID and UID, and
  * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
  *
- * int bpf_get_current_comm(char *buf, u32 size_of_buf)
+ * int bpf_get_current_comm(void *buf, u32 size_of_buf)
  * 	Description
  * 		Copy the **comm** attribute of the current task into *buf* of
  * 		*size_of_buf*. The **comm** attribute contains the name of
@@ -1023,7 +1023,7 @@ union bpf_attr {
  * 		The realm of the route for the packet associated to *skb*, or 0
  * 		if none was found.
  *
- * int bpf_perf_event_output(struct pt_regs *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
+ * int bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
  * 	Description
  * 		Write raw *data* blob into a special BPF perf event held by
  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
@@ -1068,7 +1068,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
+ * int bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
  * 	Description
  * 		This helper was provided as an easy way to load data from a
  * 		packet. It can be used to load *len* bytes from *offset* from
@@ -1085,7 +1085,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_get_stackid(struct pt_regs *ctx, struct bpf_map *map, u64 flags)
+ * int bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
  * 	Description
  * 		Walk a user or a kernel stack and return its id. To achieve
  * 		this, the helper needs *ctx*, which is a pointer to the context
@@ -1154,7 +1154,7 @@ union bpf_attr {
  * 		The checksum result, or a negative error code in case of
  * 		failure.
  *
- * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
+ * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
  * 	Description
  * 		Retrieve tunnel options metadata for the packet associated to
  * 		*skb*, and store the raw tunnel option data to the buffer *opt*
@@ -1172,7 +1172,7 @@ union bpf_attr {
  * 	Return
  * 		The size of the option data retrieved.
  *
- * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
+ * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
  * 	Description
  * 		Set tunnel options metadata for the packet associated to *skb*
  * 		to the option data contained in the raw buffer *opt* of *size*.
@@ -1511,7 +1511,7 @@ union bpf_attr {
  * 	Return
  * 		0
  *
- * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
+ * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
  * 	Description
  * 		Emulate a call to **setsockopt()** on the socket associated to
  * 		*bpf_socket*, which must be a full socket. The *level* at
@@ -1595,7 +1595,7 @@ union bpf_attr {
  * 	Return
  * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
  *
- * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
+ * int bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
  * 	Description
  * 		Redirect the packet to the socket referenced by *map* (of type
  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
@@ -1715,7 +1715,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
+ * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
  * 	Description
  * 		Emulate a call to **getsockopt()** on the socket associated to
  * 		*bpf_socket*, which must be a full socket. The *level* at
@@ -1947,7 +1947,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
+ * int bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
  * 	Description
  * 		Return a user or a kernel stack in bpf program provided buffer.
  * 		To achieve this, the helper needs *ctx*, which is a pointer
@@ -1980,7 +1980,7 @@ union bpf_attr {
  * 		A non-negative value equal to or less than *size* on success,
  * 		or a negative error in case of failure.
  *
- * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
+ * int bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
  * 	Description
  * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
  * 		it provides an easy way to load *len* bytes from *offset*
@@ -2033,7 +2033,7 @@ union bpf_attr {
  *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
  *		  packet is not forwarded or needs assist from full stack
  *
- * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
+ * int bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
  *	Description
  *		Add an entry to, or update a sockhash *map* referencing sockets.
  *		The *skops* is used as a new value for the entry associated to
@@ -2392,7 +2392,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
+ * int bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
  *	Description
  *		For socket policies, insert *len* bytes into *msg* at offset
  *		*start*.
@@ -2408,9 +2408,9 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure.
  *
- * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
+ * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
  *	Description
- *		Will remove *pop* bytes from a *msg* starting at byte *start*.
+ *		Will remove *len* bytes from a *msg* starting at byte *start*.
  *		This may result in **ENOMEM** errors under certain situations if
  *		an allocation and copy are required due to a full ring buffer.
  *		However, the helper will try to avoid doing the allocation
@@ -2505,7 +2505,7 @@ union bpf_attr {
  *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
  *		case of failure.
  *
- * int bpf_skb_ecn_set_ce(struct sk_buf *skb)
+ * int bpf_skb_ecn_set_ce(struct sk_buff *skb)
  *	Description
  *		Set ECN (Explicit Congestion Notification) field of IP header
  *		to **CE** (Congestion Encountered) if current value is **ECT**
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 77c6be96d676..a65c3b0c6935 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -794,7 +794,7 @@ union bpf_attr {
  * 		A 64-bit integer containing the current GID and UID, and
  * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
  *
- * int bpf_get_current_comm(char *buf, u32 size_of_buf)
+ * int bpf_get_current_comm(void *buf, u32 size_of_buf)
  * 	Description
  * 		Copy the **comm** attribute of the current task into *buf* of
  * 		*size_of_buf*. The **comm** attribute contains the name of
@@ -1023,7 +1023,7 @@ union bpf_attr {
  * 		The realm of the route for the packet associated to *skb*, or 0
  * 		if none was found.
  *
- * int bpf_perf_event_output(struct pt_regs *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
+ * int bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
  * 	Description
  * 		Write raw *data* blob into a special BPF perf event held by
  * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
@@ -1068,7 +1068,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
+ * int bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
  * 	Description
  * 		This helper was provided as an easy way to load data from a
  * 		packet. It can be used to load *len* bytes from *offset* from
@@ -1085,7 +1085,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_get_stackid(struct pt_regs *ctx, struct bpf_map *map, u64 flags)
+ * int bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
  * 	Description
  * 		Walk a user or a kernel stack and return its id. To achieve
  * 		this, the helper needs *ctx*, which is a pointer to the context
@@ -1154,7 +1154,7 @@ union bpf_attr {
  * 		The checksum result, or a negative error code in case of
  * 		failure.
  *
- * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
+ * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
  * 	Description
  * 		Retrieve tunnel options metadata for the packet associated to
  * 		*skb*, and store the raw tunnel option data to the buffer *opt*
@@ -1172,7 +1172,7 @@ union bpf_attr {
  * 	Return
  * 		The size of the option data retrieved.
  *
- * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
+ * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
  * 	Description
  * 		Set tunnel options metadata for the packet associated to *skb*
  * 		to the option data contained in the raw buffer *opt* of *size*.
@@ -1511,7 +1511,7 @@ union bpf_attr {
  * 	Return
  * 		0
  *
- * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
+ * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
  * 	Description
  * 		Emulate a call to **setsockopt()** on the socket associated to
  * 		*bpf_socket*, which must be a full socket. The *level* at
@@ -1595,7 +1595,7 @@ union bpf_attr {
  * 	Return
  * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
  *
- * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
+ * int bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
  * 	Description
  * 		Redirect the packet to the socket referenced by *map* (of type
  * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
@@ -1715,7 +1715,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
+ * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
  * 	Description
  * 		Emulate a call to **getsockopt()** on the socket associated to
  * 		*bpf_socket*, which must be a full socket. The *level* at
@@ -1947,7 +1947,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
+ * int bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
  * 	Description
  * 		Return a user or a kernel stack in bpf program provided buffer.
  * 		To achieve this, the helper needs *ctx*, which is a pointer
@@ -1980,7 +1980,7 @@ union bpf_attr {
  * 		A non-negative value equal to or less than *size* on success,
  * 		or a negative error in case of failure.
  *
- * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
+ * int bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
  * 	Description
  * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
  * 		it provides an easy way to load *len* bytes from *offset*
@@ -2033,7 +2033,7 @@ union bpf_attr {
  *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
  *		  packet is not forwarded or needs assist from full stack
  *
- * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
+ * int bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
  *	Description
  *		Add an entry to, or update a sockhash *map* referencing sockets.
  *		The *skops* is used as a new value for the entry associated to
@@ -2392,7 +2392,7 @@ union bpf_attr {
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
- * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
+ * int bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
  *	Description
  *		For socket policies, insert *len* bytes into *msg* at offset
  *		*start*.
@@ -2408,9 +2408,9 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure.
  *
- * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
+ * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
  *	Description
- *		Will remove *pop* bytes from a *msg* starting at byte *start*.
+ *		Will remove *len* bytes from a *msg* starting at byte *start*.
  *		This may result in **ENOMEM** errors under certain situations if
  *		an allocation and copy are required due to a full ring buffer.
  *		However, the helper will try to avoid doing the allocation
@@ -2505,7 +2505,7 @@ union bpf_attr {
  *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
  *		case of failure.
  *
- * int bpf_skb_ecn_set_ce(struct sk_buf *skb)
+ * int bpf_skb_ecn_set_ce(struct sk_buff *skb)
  *	Description
  *		Set ECN (Explicit Congestion Notification) field of IP header
  *		to **CE** (Congestion Encountered) if current value is **ECT**
-- 
2.17.1

Re: [PATCH v2 bpf-next 2/3] scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions

[Alexei Starovoitov]

On 10/5/19 8:20 PM, Andrii Nakryiko wrote:
> Enhance scripts/bpf_helpers_doc.py to emit C header with BPF helper
> definitions (to be included from libbpf's bpf_helpers.h).
> 
> Signed-off-by: Andrii Nakryiko<andriin@fb.com>
> ---
>   scripts/bpf_helpers_doc.py      |  155 +-
>   tools/lib/bpf/bpf_helper_defs.h | 2677 +++++++++++++++++++++++++++++++
>   2 files changed, 2831 insertions(+), 1 deletion(-)
>   create mode 100644 tools/lib/bpf/bpf_helper_defs.h

patch 2 adds it. patch 3 deletes it? stress testing git? ;)

Re: [PATCH v2 bpf-next 2/3] scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions

[Andrii Nakryiko]

On Sat, Oct 5, 2019 at 9:21 PM Alexei Starovoitov <ast@fb.com> wrote:
>
> On 10/5/19 8:20 PM, Andrii Nakryiko wrote:
> > Enhance scripts/bpf_helpers_doc.py to emit C header with BPF helper
> > definitions (to be included from libbpf's bpf_helpers.h).
> >
> > Signed-off-by: Andrii Nakryiko<andriin@fb.com>
> > ---
> >   scripts/bpf_helpers_doc.py      |  155 +-
> >   tools/lib/bpf/bpf_helper_defs.h | 2677 +++++++++++++++++++++++++++++++
> >   2 files changed, 2831 insertions(+), 1 deletion(-)
> >   create mode 100644 tools/lib/bpf/bpf_helper_defs.h
>
> patch 2 adds it. patch 3 deletes it? stress testing git? ;)

oh, wow... I checked cover letter's summary stats, didn't see
bpf_helpers_defs.h there and figured I didn't screw up.. wrong!