Everything should be available in the selftest part of the tree, but
providing an example without uhid and hidraw will be more easy to
follow for users.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
changes in v4:
- dropped the not-yet-implemented rdesc_fixup
- use the new API
changes in v3:
- use the new hid_get_data API
- add a comment for the report descriptor fixup to explain what is done
changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
samples/bpf/.gitignore | 1 +
samples/bpf/Makefile | 23 +++++++
samples/bpf/hid_mouse.bpf.c | 59 ++++++++++++++++
samples/bpf/hid_mouse.c | 131 ++++++++++++++++++++++++++++++++++++
4 files changed, 214 insertions(+)
create mode 100644 samples/bpf/hid_mouse.bpf.c
create mode 100644 samples/bpf/hid_mouse.c
diff --git a/samples/bpf/.gitignore b/samples/bpf/.gitignore
index 0e7bfdbff80a..65440bd618b2 100644
--- a/samples/bpf/.gitignore
+++ b/samples/bpf/.gitignore
@@ -2,6 +2,7 @@
cpustat
fds_example
hbm
+hid_mouse
ibumad
lathist
lwt_len_hist
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 8fff5ad3444b..dffca4b04a94 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -60,6 +60,8 @@ tprogs-y += xdp_redirect_map
tprogs-y += xdp_redirect
tprogs-y += xdp_monitor
+tprogs-y += hid_mouse
+
# Libbpf dependencies
LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
LIBBPF_OUTPUT = $(abspath $(BPF_SAMPLES_PATH))/libbpf
@@ -125,6 +127,8 @@ xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE)
xdp_monitor-objs := xdp_monitor_user.o $(XDP_SAMPLE)
xdp_router_ipv4-objs := xdp_router_ipv4_user.o $(XDP_SAMPLE)
+hid_mouse-objs := hid_mouse.o
+
# Tell kbuild to always build the programs
always-y := $(tprogs-y)
always-y += sockex1_kern.o
@@ -349,6 +353,8 @@ $(obj)/hbm_out_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
$(obj)/hbm.o: $(src)/hbm.h
$(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
+$(obj)/hid_mouse.o: $(obj)/hid_mouse.skel.h
+
# Override includes for xdp_sample_user.o because $(srctree)/usr/include in
# TPROGS_CFLAGS causes conflicts
XDP_SAMPLE_CFLAGS += -Wall -O2 \
@@ -434,6 +440,23 @@ $(BPF_SKELS_LINKED): $(BPF_OBJS_LINKED) $(BPFTOOL)
@echo " BPF GEN-SKEL" $(@:.skel.h=)
$(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=)) > $@
+# Generate BPF skeletons for non XDP progs
+OTHER_BPF_SKELS := hid_mouse.skel.h
+
+hid_mouse.skel.h-deps := hid_mouse.bpf.o
+
+OTHER_BPF_SRCS_LINKED := $(patsubst %.skel.h,%.bpf.c, $(OTHER_BPF_SKELS))
+OTHER_BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(OTHER_BPF_SRCS_LINKED))
+OTHER_BPF_SKELS_LINKED := $(addprefix $(obj)/,$(OTHER_BPF_SKELS))
+
+$(OTHER_BPF_SKELS_LINKED): $(OTHER_BPF_OBJS_LINKED) $(BPFTOOL)
+ @echo " BPF GEN-OBJ " $(@:.skel.h=)
+ $(Q)$(BPFTOOL) gen object $(@:.skel.h=.lbpf.o) $(addprefix $(obj)/,$($(@F)-deps))
+ @echo " BPF GEN-SKEL" $(@:.skel.h=)
+ $(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=_lskel)) > $@
+# $(call msg,GEN-SKEL,$@)
+# $(Q)$(BPFTOOL) gen skeleton $< > $@
+
# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
# But, there is no easy way to fix it, so just exclude it since it is
# useless for BPF samples.
diff --git a/samples/bpf/hid_mouse.bpf.c b/samples/bpf/hid_mouse.bpf.c
new file mode 100644
index 000000000000..45cc26b70f5f
--- /dev/null
+++ b/samples/bpf/hid_mouse.bpf.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Note: for the following code to compile, we need HID to be included
+ * in vmlinuz (CONFIG_HID=y).
+ * If HID is compiled as a separate module, we need to use the vmlinux.h
+ * which contains the various hid symbols, it can be generated through:
+ *
+ * $> ./tools/bpf/bpftool/bpftool btf dump \
+ * file /sys/kernel/btf/hid format c > samples/bpf/vmlinux.h
+ *
+ * Once the code is compiled, the fact that HID is a separate module
+ * or not is not an issue, the same binary will run similarily.
+ */
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+extern __u8 *hid_bpf_kfunc_get_data(struct hid_bpf_ctx *ctx,
+ unsigned int offset,
+ const size_t __sz) __ksym;
+extern void hid_bpf_kfunc_data_release(__u8 *data) __ksym;
+extern int hid_bpf_kfunc_hw_request(struct hid_bpf_ctx *ctx) __ksym;
+
+#define BUS_USB 3
+
+SEC("fentry/hid_bpf_device_event")
+int BPF_KPROBE(hid_event, struct hid_bpf_ctx *hctx, __s64 type)
+{
+ __u8 *rw_data = hid_bpf_kfunc_get_data(hctx, 0, 5);
+
+ if (!rw_data)
+ return 0;
+
+ if (hctx->bus == BUS_USB) {
+ /* note: the following call prevents the program to be loaded:
+ * hid_bpf_device_event() is not sleepable when this function is.
+ */
+ hid_bpf_kfunc_hw_request(hctx);
+
+ bpf_printk("data: %02x %02x %02x", rw_data[0], rw_data[1], rw_data[4]);
+ }
+
+ hid_bpf_kfunc_data_release(rw_data);
+
+ return 0;
+}
+
+SEC("fmod_ret/hid_bpf_device_event")
+int BPF_PROG(hid_mod_event, struct hid_bpf_ctx *hctx, __s64 type)
+{
+ /* prevent any USB event to go through the HID stack */
+ if (hctx->bus == BUS_USB)
+ return -1;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/hid_mouse.c b/samples/bpf/hid_mouse.c
new file mode 100644
index 000000000000..aace0b959d3b
--- /dev/null
+++ b/samples/bpf/hid_mouse.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Benjamin Tissoires
+ */
+
+/* not sure why but this doesn't get preoperly imported */
+#define __must_check
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include <linux/bpf.h>
+#include <linux/err.h>
+
+#include "bpf_util.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "hid_mouse.skel.h"
+
+static char *sysfs_path;
+static int sysfs_fd;
+static int prog_count;
+
+static bool running = true;
+
+struct prog {
+ int fd;
+ struct bpf_link *link;
+ enum bpf_attach_type type;
+};
+
+static struct prog progs[10];
+
+static void int_exit(int sig)
+{
+ running = false;
+ exit(0);
+}
+
+static void usage(const char *prog)
+{
+ fprintf(stderr,
+ "%s: %s /sys/bus/hid/devices/0BUS:0VID:0PID:00ID/uevent\n\n",
+ __func__, prog);
+}
+
+int main(int argc, char **argv)
+{
+ struct hid_mouse_lskel *skel;
+ int prog_fd, err;
+ const char *optstr = "";
+ int opt;
+ char filename[256];
+
+ LIBBPF_OPTS(bpf_test_run_opts, topts,
+ .repeat = 1,
+ );
+
+ while ((opt = getopt(argc, argv, optstr)) != -1) {
+ switch (opt) {
+ default:
+ usage(basename(argv[0]));
+ return 1;
+ }
+ }
+
+ if (optind == argc) {
+ usage(basename(argv[0]));
+ return 1;
+ }
+
+ sysfs_path = argv[optind];
+ if (!sysfs_path) {
+ perror("sysfs");
+ return 1;
+ }
+
+ skel = hid_mouse_lskel__open_and_load();
+ if (!skel) {
+ fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
+ return -1;
+ }
+
+ err = hid_mouse_lskel__attach(skel);
+ if (err)
+ goto cleanup;
+
+ //prog_fd = bpf_program__fd(skel->progs.hid_event);
+ //err = bpf_prog_test_run_opts(prog_fd, &topts);
+
+// sysfs_fd = open(sysfs_path, O_RDONLY);
+//
+//// bpf_object__for_each_program(prog, obj) {
+//// progs[prog_count].fd = bpf_program__fd(prog);
+//// progs[prog_count].type = bpf_program__get_expected_attach_type(prog);
+//// progs[prog_count].link = bpf_program__attach(prog);
+//// if (libbpf_get_error(progs[prog_count].link)) {
+//// fprintf(stderr, "bpf_prog_attach: err=%m\n");
+//// progs[prog_count].fd = 0;
+//// progs[prog_count].link = NULL;
+//// goto cleanup;
+//// }
+//// prog_count++;
+//// }
+//
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+//
+//// err = bpf_obj_get_info_by_fd(progs[0].fd, &info, &info_len);
+//// if (err) {
+//// printf("can't get prog info - %s\n", strerror(errno));
+//// goto cleanup;
+//// }
+//
+ while (running)
+ ;
+
+ cleanup:
+ hid_mouse_lskel__destroy(skel);
+
+ return err;
+}
--
2.35.1
