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bpf: expose information about supported xdp metadata kfunc 

Add new xdp-rx-metadata-features member to netdev netlink
which exports a bitmask of supported kfuncs. Most of the patch
is autogenerated (headers), the only relevant part is netdev.yaml
and the changes in netdev-genl.c to marshal into netlink.

Example output on veth:

$ ip link add veth0 type veth peer name veth1 # ifndex == 12
$ ./tools/net/ynl/samples/netdev 12

Select ifc ($ifindex; or 0 = dump; or -2 ntf check): 12
   veth1[12]    xdp-features (23): basic redirect rx-sg xdp-rx-metadata-features (3): timestamp hash xdp-zc-max-segs=0

Cc: netdev@vger.kernel.org
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230913171350.369987-3-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Stanislav Fomichev 2023-09-13 10:13:49 -07:00 committed by Martin KaFai Lau
parent fc45c5b642
commit a9c2a60854
8 changed files with 78 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
Documentation/netlink/specs/netdev.yaml
View File

@ -42,6 +42,19 @@ definitions:
doc:
This feature informs if netdev implements non-linear XDP buffer
support in ndo_xdp_xmit callback.
-
type: flags
name: xdp-rx-metadata
render-max: true
entries:
-
name: timestamp
doc:
Device is capable of exposing receive HW timestamp via bpf_xdp_metadata_rx_timestamp().
-
name: hash
doc:
Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
attribute-sets:
-
@ -68,6 +81,13 @@ attribute-sets:
type: u32
checks:
min: 1
-
name: xdp-rx-metadata-features
doc: Bitmask of supported XDP receive metadata features.
See Documentation/networking/xdp-rx-metadata.rst for more details.
type: u64
enum: xdp-rx-metadata
enum-as-flags: true
operations:
list:
@ -84,6 +104,7 @@ operations:
- ifindex
- xdp-features
- xdp-zc-max-segs
- xdp-rx-metadata-features
dump:
reply: *dev-all
-

7
Documentation/networking/xdp-rx-metadata.rst
View File

@ -105,6 +105,13 @@ bpf_tail_call
Adding programs that access metadata kfuncs to the ``BPF_MAP_TYPE_PROG_ARRAY``
is currently not supported.
Supported Devices
=================
It is possible to query which kfunc the particular netdev implements via
netlink. See ``xdp-rx-metadata-features`` attribute set in
``Documentation/netlink/specs/netdev.yaml``.
Example
=======

5
include/net/xdp.h
View File

@ -386,19 +386,22 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
/* Define the relationship between xdp-rx-metadata kfunc and
* various other entities:
* - xdp_rx_metadata enum
* - netdev netlink enum (Documentation/netlink/specs/netdev.yaml)
* - kfunc name
* - xdp_metadata_ops field
*/
#define XDP_METADATA_KFUNC_xxx \
XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_TIMESTAMP, \
NETDEV_XDP_RX_METADATA_TIMESTAMP, \
bpf_xdp_metadata_rx_timestamp, \
xmo_rx_timestamp) \
XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_HASH, \
NETDEV_XDP_RX_METADATA_HASH, \
bpf_xdp_metadata_rx_hash, \
xmo_rx_hash) \
enum xdp_rx_metadata {
#define XDP_METADATA_KFUNC(name, _, __) name,
#define XDP_METADATA_KFUNC(name, _, __, ___) name,
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC
MAX_XDP_METADATA_KFUNC,

16
include/uapi/linux/netdev.h
View File

@ -38,11 +38,27 @@ enum netdev_xdp_act {
NETDEV_XDP_ACT_MASK = 127,
};
/**
* enum netdev_xdp_rx_metadata
* @NETDEV_XDP_RX_METADATA_TIMESTAMP: Device is capable of exposing receive HW
* timestamp via bpf_xdp_metadata_rx_timestamp().
* @NETDEV_XDP_RX_METADATA_HASH: Device is capable of exposing receive packet
* hash via bpf_xdp_metadata_rx_hash().
*/
enum netdev_xdp_rx_metadata {
NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
NETDEV_XDP_RX_METADATA_HASH = 2,
/* private: */
NETDEV_XDP_RX_METADATA_MASK = 3,
};
enum {
NETDEV_A_DEV_IFINDEX = 1,
NETDEV_A_DEV_PAD,
NETDEV_A_DEV_XDP_FEATURES,
NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
__NETDEV_A_DEV_MAX,
NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)

2
kernel/bpf/offload.c
View File

@ -845,7 +845,7 @@ void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id)
if (!ops)
goto out;
#define XDP_METADATA_KFUNC(name, _, xmo) \
#define XDP_METADATA_KFUNC(name, _, __, xmo) \
if (func_id == bpf_xdp_metadata_kfunc_id(name)) p = ops->xmo;
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC

12
net/core/netdev-genl.c
View File

@ -5,6 +5,7 @@
#include <linux/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/xdp.h>
#include "netdev-genl-gen.h"
@ -12,15 +13,24 @@ static int
netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
const struct genl_info *info)
{
u64 xdp_rx_meta = 0;
void *hdr;
hdr = genlmsg_iput(rsp, info);
if (!hdr)
return -EMSGSIZE;
#define XDP_METADATA_KFUNC(_, flag, __, xmo) \
if (netdev->xdp_metadata_ops && netdev->xdp_metadata_ops->xmo) \
xdp_rx_meta |= flag;
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC
if (nla_put_u32(rsp, NETDEV_A_DEV_IFINDEX, netdev->ifindex) ||
nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_FEATURES,
netdev->xdp_features, NETDEV_A_DEV_PAD)) {
netdev->xdp_features, NETDEV_A_DEV_PAD) ||
nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
xdp_rx_meta, NETDEV_A_DEV_PAD)) {
genlmsg_cancel(rsp, hdr);
return -EINVAL;
}

4
net/core/xdp.c
View File

@ -741,7 +741,7 @@ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash,
__diag_pop();
BTF_SET8_START(xdp_metadata_kfunc_ids)
#define XDP_METADATA_KFUNC(_, name, __) BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS)
#define XDP_METADATA_KFUNC(_, __, name, ___) BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS)
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC
BTF_SET8_END(xdp_metadata_kfunc_ids)
@ -752,7 +752,7 @@ static const struct btf_kfunc_id_set xdp_metadata_kfunc_set = {
};
BTF_ID_LIST(xdp_metadata_kfunc_ids_unsorted)
#define XDP_METADATA_KFUNC(name, str, _) BTF_ID(func, str)
#define XDP_METADATA_KFUNC(name, _, str, __) BTF_ID(func, str)
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC

16
tools/include/uapi/linux/netdev.h
View File

@ -38,11 +38,27 @@ enum netdev_xdp_act {
NETDEV_XDP_ACT_MASK = 127,
};
/**
* enum netdev_xdp_rx_metadata
* @NETDEV_XDP_RX_METADATA_TIMESTAMP: Device is capable of exposing receive HW
* timestamp via bpf_xdp_metadata_rx_timestamp().
* @NETDEV_XDP_RX_METADATA_HASH: Device is capable of exposing receive packet
* hash via bpf_xdp_metadata_rx_hash().
*/
enum netdev_xdp_rx_metadata {
NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
NETDEV_XDP_RX_METADATA_HASH = 2,
/* private: */
NETDEV_XDP_RX_METADATA_MASK = 3,
};
enum {
NETDEV_A_DEV_IFINDEX = 1,
NETDEV_A_DEV_PAD,
NETDEV_A_DEV_XDP_FEATURES,
NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
__NETDEV_A_DEV_MAX,
NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)