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-rw-r--r--tools/firmware-utils/Makefile1
-rw-r--r--tools/firmware-utils/src/nec-enc.c129
2 files changed, 130 insertions, 0 deletions
diff --git a/tools/firmware-utils/Makefile b/tools/firmware-utils/Makefile
index 864a3df15d..7745b7bab2 100644
--- a/tools/firmware-utils/Makefile
+++ b/tools/firmware-utils/Makefile
@@ -85,6 +85,7 @@ define Host/Compile
$(call cc,mkdlinkfw mkdlinkfw-lib, -lz -Wall --std=c99)
$(call cc,dns313-header, -Wall)
$(call cc,mksercommfw, -Wall)
+ $(call cc,nec-enc, -Wall)
endef
define Host/Install
diff --git a/tools/firmware-utils/src/nec-enc.c b/tools/firmware-utils/src/nec-enc.c
new file mode 100644
index 0000000000..3c4e38721e
--- /dev/null
+++ b/tools/firmware-utils/src/nec-enc.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * nec-enc.c - encode/decode nec firmware with key
+ *
+ * based on xorimage.c in OpenWrt
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#define KEY_LEN 16
+#define PATTERN_LEN 251
+
+static int
+xor_pattern(uint8_t *data, size_t len, const char *key, int k_len, int k_off)
+{
+ int offset = k_off;
+
+ while (len--) {
+ *data ^= key[offset];
+ data++;
+ offset = (offset + 1) % k_len;
+ }
+
+ return offset;
+}
+
+static void xor_data(uint8_t *data, size_t len, const uint8_t *pattern)
+{
+ for (int i = 0; i < len; i++) {
+ *data ^= pattern[i];
+ data++;
+ }
+}
+
+static void __attribute__((noreturn)) usage(void)
+{
+ fprintf(stderr, "Usage: nec-enc -i infile -o outfile -k <key>\n");
+ exit(EXIT_FAILURE);
+}
+
+static unsigned char buf_pattern[4096], buf[4096];
+
+int main(int argc, char **argv)
+{
+ int k_off = 0, ptn = 0, c, ret = EXIT_SUCCESS;
+ char *ifn = NULL, *ofn = NULL, *key = NULL;
+ size_t n, k_len;
+ FILE *out, *in;
+
+ while ((c = getopt(argc, argv, "i:o:k:h")) != -1) {
+ switch (c) {
+ case 'i':
+ ifn = optarg;
+ break;
+ case 'o':
+ ofn = optarg;
+ break;
+ case 'k':
+ key = optarg;
+ break;
+ case 'h':
+ default:
+ usage();
+ }
+ }
+
+ if (optind != argc || optind == 1) {
+ fprintf(stderr, "illegal arg \"%s\"\n", argv[optind]);
+ usage();
+ }
+
+ in = fopen(ifn, "r");
+ if (!in) {
+ perror("can not open input file");
+ usage();
+ }
+
+ out = fopen(ofn, "w");
+ if (!out) {
+ perror("can not open output file");
+ usage();
+ }
+
+ if (!key) {
+ fprintf(stderr, "key is not specified\n");
+ usage();
+ }
+
+ k_len = strnlen(key, KEY_LEN + 1);
+ if (k_len == 0 || k_len > KEY_LEN) {
+ fprintf(stderr, "key length is not in range (0,%d)\n", KEY_LEN);
+ usage();
+ }
+
+ while ((n = fread(buf, 1, sizeof(buf), in)) > 0) {
+ for (int i = 0; i < n; i++) {
+ buf_pattern[i] = ptn + 1;
+ ptn++;
+
+ if (ptn > 250)
+ ptn = 0;
+ }
+
+ k_off = xor_pattern(buf_pattern, n, key, k_len, k_off);
+ xor_data(buf, n, buf_pattern);
+
+ if (fwrite(buf, 1, n, out) != n) {
+ perror("failed to write");
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+ }
+
+ if (ferror(in)) {
+ perror("failed to read");
+ ret = EXIT_FAILURE;
+ goto out;
+ }
+
+out:
+ fclose(in);
+ fclose(out);
+ return ret;
+}