bpf: add selftest for lirc_mode2 type program

This is simple test over rc-loopback.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/.gitignore

@@ -17,3 +17,4 @@ test_sock_addr
 urandom_read
 test_btf
 test_sockmap
+test_lirc_mode2_user

tools/testing/selftests/bpf/Makefile

@@ -24,7 +24,7 @@ urandom_read: urandom_read.c
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
 	test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
-	test_sock test_btf test_sockmap
+	test_sock test_btf test_sockmap test_lirc_mode2_user
 
 TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
 	test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o     \
@@ -34,7 +34,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
 	sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
 	test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
 	test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
-	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o
+	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \
@@ -44,7 +44,8 @@ TEST_PROGS := test_kmod.sh \
 	test_offload.py \
 	test_sock_addr.sh \
 	test_tunnel.sh \
-	test_lwt_seg6local.sh
+	test_lwt_seg6local.sh \
+	test_lirc_mode2.sh
 
 # Compile but not part of 'make run_tests'
 TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr

tools/testing/selftests/bpf/bpf_helpers.h

@@ -126,6 +126,11 @@ static int (*bpf_lwt_seg6_action)(void *ctx, unsigned int action, void *param,
 static int (*bpf_lwt_seg6_adjust_srh)(void *ctx, unsigned int offset,
 				      unsigned int len) =
 	(void *) BPF_FUNC_lwt_seg6_adjust_srh;
+static int (*bpf_rc_repeat)(void *ctx) =
+	(void *) BPF_FUNC_rc_repeat;
+static int (*bpf_rc_keydown)(void *ctx, unsigned int protocol,
+			     unsigned long long scancode, unsigned int toggle) =
+	(void *) BPF_FUNC_rc_keydown;
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

tools/testing/selftests/bpf/test_lirc_mode2.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+GREEN='\033[0;92m'
+RED='\033[0;31m'
+NC='\033[0m' # No Color
+
+modprobe rc-loopback
+
+for i in /sys/class/rc/rc*
+do
+	if grep -q DRV_NAME=rc-loopback $i/uevent
+	then
+		LIRCDEV=$(grep DEVNAME= $i/lirc*/uevent | sed sQDEVNAME=Q/dev/Q)
+	fi
+done
+
+if [ -n $LIRCDEV ];
+then
+	TYPE=lirc_mode2
+	./test_lirc_mode2_user $LIRCDEV
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		echo -e ${RED}"FAIL: $TYPE"${NC}
+	else
+		echo -e ${GREEN}"PASS: $TYPE"${NC}
+	fi
+fi

tools/testing/selftests/bpf/test_lirc_mode2_kern.c

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <sean@mess.org>
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include "bpf_helpers.h"
+
+SEC("lirc_mode2")
+int bpf_decoder(unsigned int *sample)
+{
+	if (LIRC_IS_PULSE(*sample)) {
+		unsigned int duration = LIRC_VALUE(*sample);
+
+		if (duration & 0x10000)
+			bpf_rc_keydown(sample, 0x40, duration & 0xffff, 0);
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_lirc_mode2_user.c

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <sean@mess.org>
+
+// A lirc chardev is a device representing a consumer IR (cir) device which
+// can receive infrared signals from remote control and/or transmit IR.
+//
+// IR is sent as a series of pulses and space somewhat like morse code. The
+// BPF program can decode this into scancodes so that rc-core can translate
+// this into input key codes using the rc keymap.
+//
+// This test works by sending IR over rc-loopback, so the IR is processed by
+// BPF and then decoded into scancodes. The lirc chardev must be the one
+// associated with rc-loopback, see the output of ir-keytable(1).
+//
+// The following CONFIG options must be enabled for the test to succeed:
+// CONFIG_RC_CORE=y
+// CONFIG_BPF_RAWIR_EVENT=y
+// CONFIG_RC_LOOPBACK=y
+
+// Steps:
+// 1. Open the /dev/lircN device for rc-loopback (given on command line)
+// 2. Attach bpf_lirc_mode2 program which decodes some IR.
+// 3. Send some IR to the same IR device; since it is loopback, this will
+//    end up in the bpf program
+// 4. bpf program should decode IR and report keycode
+// 5. We can read keycode from same /dev/lirc device
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <poll.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "bpf_util.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+int main(int argc, char **argv)
+{
+	struct bpf_object *obj;
+	int ret, lircfd, progfd, mode;
+	int testir = 0x1dead;
+	u32 prog_ids[10], prog_flags[10], prog_cnt;
+
+	if (argc != 2) {
+		printf("Usage: %s /dev/lircN\n", argv[0]);
+		return 2;
+	}
+
+	ret = bpf_prog_load("test_lirc_mode2_kern.o",
+			    BPF_PROG_TYPE_LIRC_MODE2, &obj, &progfd);
+	if (ret) {
+		printf("Failed to load bpf program\n");
+		return 1;
+	}
+
+	lircfd = open(argv[1], O_RDWR | O_NONBLOCK);
+	if (lircfd == -1) {
+		printf("failed to open lirc device %s: %m\n", argv[1]);
+		return 1;
+	}
+
+	/* Let's try detach it before it was ever attached */
+	ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+	if (ret != -1 || errno != ENOENT) {
+		printf("bpf_prog_detach2 not attached should fail: %m\n");
+		return 1;
+	}
+
+	mode = LIRC_MODE_SCANCODE;
+	if (ioctl(lircfd, LIRC_SET_REC_MODE, &mode)) {
+		printf("failed to set rec mode: %m\n");
+		return 1;
+	}
+
+	prog_cnt = 10;
+	ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+			     &prog_cnt);
+	if (ret) {
+		printf("Failed to query bpf programs on lirc device: %m\n");
+		return 1;
+	}
+
+	if (prog_cnt != 0) {
+		printf("Expected nothing to be attached\n");
+		return 1;
+	}
+
+	ret = bpf_prog_attach(progfd, lircfd, BPF_LIRC_MODE2, 0);
+	if (ret) {
+		printf("Failed to attach bpf to lirc device: %m\n");
+		return 1;
+	}
+
+	/* Write raw IR */
+	ret = write(lircfd, &testir, sizeof(testir));
+	if (ret != sizeof(testir)) {
+		printf("Failed to send test IR message: %m\n");
+		return 1;
+	}
+
+	struct pollfd pfd = { .fd = lircfd, .events = POLLIN };
+	struct lirc_scancode lsc;
+
+	poll(&pfd, 1, 100);
+
+	/* Read decoded IR */
+	ret = read(lircfd, &lsc, sizeof(lsc));
+	if (ret != sizeof(lsc)) {
+		printf("Failed to read decoded IR: %m\n");
+		return 1;
+	}
+
+	if (lsc.scancode != 0xdead || lsc.rc_proto != 64) {
+		printf("Incorrect scancode decoded\n");
+		return 1;
+	}
+
+	prog_cnt = 10;
+	ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+			     &prog_cnt);
+	if (ret) {
+		printf("Failed to query bpf programs on lirc device: %m\n");
+		return 1;
+	}
+
+	if (prog_cnt != 1) {
+		printf("Expected one program to be attached\n");
+		return 1;
+	}
+
+	/* Let's try detaching it now it is actually attached */
+	ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+	if (ret) {
+		printf("bpf_prog_detach2: returned %m\n");
+		return 1;
+	}
+
+	return 0;
+}