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Subject[PATCH bpf-next v3 04/17] libbpf: add HID program type and API
Date
HID-bpf program type are needing new SECs.
To bind a hid-bpf program, we can rely on bpf_program__attach_fd()
so export a new function to the API.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v3:
- squashed the libbpf changes into 1
- moved bpf_program__attach_hid to 0.8.0
- added SEC_DEF("hid/driver_event")

changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
tools/include/uapi/linux/bpf.h | 31 +++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.c | 23 +++++++++++++++++------
tools/lib/bpf/libbpf.h | 2 ++
tools/lib/bpf/libbpf.map | 1 +
4 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 99fab54ae9c0..0e8438e93768 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -952,6 +952,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_LSM,
BPF_PROG_TYPE_SK_LOOKUP,
BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
+ BPF_PROG_TYPE_HID,
};

enum bpf_attach_type {
@@ -997,6 +998,10 @@ enum bpf_attach_type {
BPF_SK_REUSEPORT_SELECT,
BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
BPF_PERF_EVENT,
+ BPF_HID_DEVICE_EVENT,
+ BPF_HID_RDESC_FIXUP,
+ BPF_HID_USER_EVENT,
+ BPF_HID_DRIVER_EVENT,
__MAX_BPF_ATTACH_TYPE
};

@@ -1011,6 +1016,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_NETNS = 5,
BPF_LINK_TYPE_XDP = 6,
BPF_LINK_TYPE_PERF_EVENT = 7,
+ BPF_LINK_TYPE_HID = 8,

MAX_BPF_LINK_TYPE,
};
@@ -1118,6 +1124,16 @@ enum bpf_link_type {
*/
#define BPF_F_XDP_HAS_FRAGS (1U << 5)

+/* HID flag used in BPF_LINK_CREATE command
+ *
+ * NONE(default): The bpf program will be added at the tail of the list
+ * of existing bpf program for this type.
+ *
+ * BPF_F_INSERT_HEAD: The bpf program will be added at the beginning
+ * of the list of existing bpf program for this type..
+ */
+#define BPF_F_INSERT_HEAD (1U << 0)
+
/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
* the following extensions:
*
@@ -5129,6 +5145,16 @@ union bpf_attr {
* The **hash_algo** is returned on success,
* **-EOPNOTSUP** if the hash calculation failed or **-EINVAL** if
* invalid arguments are passed.
+ *
+ * void *bpf_hid_get_data(void *ctx, u64 offset, u64 size)
+ * Description
+ * Returns a pointer to the data associated with context at the given
+ * offset and size (in bytes).
+ *
+ * Note: the returned pointer is refcounted and must be dereferenced
+ * by a call to bpf_hid_discard;
+ * Return
+ * The pointer to the data. On error, a null value is returned.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5325,6 +5351,7 @@ union bpf_attr {
FN(copy_from_user_task), \
FN(skb_set_tstamp), \
FN(ima_file_hash), \
+ FN(hid_get_data), \
/* */

/* integer value in 'imm' field of BPF_CALL instruction selects which helper
@@ -5925,6 +5952,10 @@ struct bpf_link_info {
struct {
__u32 ifindex;
} xdp;
+ struct {
+ __s32 hidraw_number;
+ __u32 attach_type;
+ } hid;
};
} __attribute__((aligned(8)));

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 43161fdd44bb..6b9ba313eb5b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8675,6 +8675,10 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE),
SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+ SEC_DEF("hid/device_event", HID, BPF_HID_DEVICE_EVENT, SEC_ATTACHABLE_OPT),
+ SEC_DEF("hid/rdesc_fixup", HID, BPF_HID_RDESC_FIXUP, SEC_ATTACHABLE_OPT),
+ SEC_DEF("hid/user_event", HID, BPF_HID_USER_EVENT, SEC_ATTACHABLE_OPT),
+ SEC_DEF("hid/driver_event", HID, BPF_HID_DRIVER_EVENT, SEC_ATTACHABLE_OPT),
};

static size_t custom_sec_def_cnt;
@@ -10630,10 +10634,11 @@ static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_li

static struct bpf_link *
bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id,
- const char *target_name)
+ const char *target_name, __u32 flags)
{
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
- .target_btf_id = btf_id);
+ .target_btf_id = btf_id,
+ .flags = flags);
enum bpf_attach_type attach_type;
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
@@ -10667,19 +10672,19 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id
struct bpf_link *
bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd)
{
- return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
+ return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup", 0);
}

struct bpf_link *
bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
{
- return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
+ return bpf_program__attach_fd(prog, netns_fd, 0, "netns", 0);
}

struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
{
/* target_fd/target_ifindex use the same field in LINK_CREATE */
- return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
+ return bpf_program__attach_fd(prog, ifindex, 0, "xdp", 0);
}

struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
@@ -10705,7 +10710,7 @@ struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
if (btf_id < 0)
return libbpf_err_ptr(btf_id);

- return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace");
+ return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace", 0);
} else {
/* no target, so use raw_tracepoint_open for compatibility
* with old kernels
@@ -10760,6 +10765,12 @@ static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_l
return libbpf_get_error(*link);
}

+struct bpf_link *
+bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd, __u32 flags)
+{
+ return bpf_program__attach_fd(prog, hid_fd, 0, "hid", flags);
+}
+
struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
{
struct bpf_link *link = NULL;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c1b0c2ef14d8..13dff4865da5 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -529,6 +529,8 @@ struct bpf_iter_attach_opts {
LIBBPF_API struct bpf_link *
bpf_program__attach_iter(const struct bpf_program *prog,
const struct bpf_iter_attach_opts *opts);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd, __u32 flags);

/*
* Libbpf allows callers to adjust BPF programs before being loaded
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index df1b947792c8..cd8da9a8bf36 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -442,6 +442,7 @@ LIBBPF_0.7.0 {

LIBBPF_0.8.0 {
global:
+ bpf_program__attach_hid;
libbpf_register_prog_handler;
libbpf_unregister_prog_handler;
} LIBBPF_0.7.0;
--
2.35.1
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