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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2023 Benjamin Tissoires
*/
#include "vmlinux.h"
#include "hid_bpf.h"
#include "hid_bpf_helpers.h"
#include <bpf/bpf_tracing.h>
#define VID_IOGEAR 0x258A /* VID is shared with SinoWealth and Glorious and prob others */
#define PID_MOMENTUM 0x0027
HID_BPF_CONFIG(
HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_IOGEAR, PID_MOMENTUM)
);
/*
* The IOGear Kaliber Gaming MMOmentum Pro mouse has multiple buttons (12)
* but only 5 are accessible out of the box because the report descriptor
* marks the other buttons as constants.
* We just fix the report descriptor to enable those missing 7 buttons.
*/
SEC("fmod_ret/hid_bpf_rdesc_fixup")
int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx)
{
const u8 offsets[] = {84, 112, 140};
__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
if (!data)
return 0; /* EPERM check */
/* if not Keyboard */
if (data[3] != 0x06)
return 0;
for (int idx = 0; idx < ARRAY_SIZE(offsets); idx++) {
u8 offset = offsets[idx];
/* if Input (Cnst,Var,Abs) , make it Input (Data,Var,Abs) */
if (data[offset] == 0x81 && data[offset + 1] == 0x03)
data[offset + 1] = 0x02;
}
return 0;
}
SEC("syscall")
int probe(struct hid_bpf_probe_args *ctx)
{
/* only bind to the keyboard interface */
ctx->retval = ctx->rdesc_size != 213;
if (ctx->retval)
ctx->retval = -EINVAL;
return 0;
}
char _license[] SEC("license") = "GPL";
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