firmware-utils mkmerakifw: firmware generator for MR18

This patch adds firmware generation tool for Cisco's MR18

Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@47856 3c298f89-4303-0410-b956-a3cf2f4a3e73

2 files changed, 264 insertions, 0 deletions

diff --git a/tools/firmware-utils/Makefile b/tools/firmware-utils/Makefile
index bd69cb419c..dc922b0360 100644
--- a/tools/firmware-utils/Makefile
+++ b/tools/firmware-utils/Makefile
@@ -73,6 +73,7 @@ define Host/Compile
 	$(call cc,mkrtn56uimg, -lz)
 	$(call cc,dgn3500sum)
 	$(call cc,edimax_fw_header, -Wall)
+	$(call cc,mkmerakifw sha1, -Wall)
 endef
 
 define Host/Install
diff --git a/tools/firmware-utils/src/mkmerakifw.c b/tools/firmware-utils/src/mkmerakifw.c
new file mode 100644
index 0000000000..241bb33400
--- /dev/null
+++ b/tools/firmware-utils/src/mkmerakifw.c
@@ -0,0 +1,263 @@
+/*
+ * Copyright (C) 2015 Thomas Hebb <tommyhebb@gmail.com>
+ *
+ * The format of the header this tool generates was first documented by
+ * Chris Blake <chrisrblake93 (at) gmail.com> in a shell script of the
+ * same purpose. I have created this reimplementation at his request. The
+ * original script can be found at:
+ * <https://github.com/riptidewave93/meraki-partbuilder>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <libgen.h>
+#include <getopt.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+#include "sha1.h"
+
+#define PADDING_BYTE		0xff
+
+#define HDR_LENGTH		0x00000400
+#define HDR_OFF_MAGIC1		0
+#define HDR_OFF_HDRLEN		4
+#define HDR_OFF_IMAGELEN	8
+#define HDR_OFF_CHECKSUM	12
+#define HDR_OFF_MAGIC2		32
+#define HDR_OFF_FILLER		36
+#define HDR_OFF_STATICHASH	40
+
+struct board_info {
+	uint32_t magic;
+	uint32_t imagelen;
+	unsigned char statichash[20];
+	char *id;
+	char *description;
+};
+
+/*
+ * Globals
+ */
+static char *progname;
+
+static char *board_id;
+static const struct board_info *board;
+
+static const struct board_info boards[] = {
+	{
+		.id		= "mr18",
+		.description	= "Meraki MR18 Access Point",
+		.magic		= 0x8e73ed8a,
+		.imagelen	= 0x00800000,
+		.statichash	= {0xda, 0x39, 0xa3, 0xee, 0x5e,
+				   0x6b, 0x4b, 0x0d, 0x32, 0x55,
+				   0xbf, 0xef, 0x95, 0x60, 0x18,
+				   0x90, 0xaf, 0xd8, 0x07, 0x09},
+	}, {
+		/* terminating entry */
+	}
+};
+
+/*
+ * Message macros
+ */
+#define ERR(fmt, ...) do { \
+	fflush(0); \
+	fprintf(stderr, "[%s] *** error: " fmt "\n", \
+			progname, ## __VA_ARGS__); \
+} while (0)
+
+#define ERRS(fmt, ...) do { \
+	int save = errno; \
+	fflush(0); \
+	fprintf(stderr, "[%s] *** error: " fmt "\n", \
+			progname, ## __VA_ARGS__, strerror(save)); \
+} while (0)
+
+static const struct board_info *find_board(const char *id)
+{
+	const struct board_info *ret;
+	const struct board_info *board;
+
+	ret = NULL;
+	for (board = boards; board->id != NULL; board++) {
+		if (strcasecmp(id, board->id) == 0) {
+			ret = board;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void usage(int status)
+{
+	FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
+	const struct board_info *board;
+
+	fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
+	fprintf(stream,
+"\n"
+"Options:\n"
+"  -B <board>      create image for the board specified with <board>\n"
+"  -i <file>       read kernel image from the file <file>\n"
+"  -o <file>       write output to the file <file>\n"
+"  -s              strip padding from the end of the image\n"
+"  -h              show this screen\n"
+	);
+
+	fprintf(stream, "\nBoards:\n");
+	for (board = boards; board->id != NULL; board++)
+		fprintf(stream, "  %-16s%s\n", board->id, board->description);
+
+	exit(status);
+}
+
+void writel(unsigned char *buf, size_t offset, uint32_t value)
+{
+	value = htonl(value);
+	memcpy(buf + offset, &value, sizeof(uint32_t));
+}
+
+int main(int argc, char *argv[])
+{
+	int ret = EXIT_FAILURE;
+	long klen;
+	size_t kspace;
+	unsigned char *kernel;
+	size_t buflen;
+	unsigned char *buf;
+	bool strip_padding = false;
+	char *ofname = NULL, *ifname = NULL;
+	FILE *out, *in;
+
+	progname = basename(argv[0]);
+
+	while (1) {
+		int c;
+
+		c = getopt(argc, argv, "B:i:o:sh");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'B':
+			board_id = optarg;
+			break;
+		case 'i':
+			ifname = optarg;
+			break;
+		case 'o':
+			ofname = optarg;
+			break;
+		case 's':
+			strip_padding = true;
+			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
+			break;
+		default:
+			usage(EXIT_FAILURE);
+			break;
+		}
+	}
+
+	if (board_id == NULL) {
+		ERR("no board specified");
+		goto err;
+	}
+
+	board = find_board(board_id);
+	if (board == NULL) {
+		ERR("unknown board \"%s\"", board_id);
+		goto err;
+	}
+
+	if (ifname == NULL) {
+		ERR("no input file specified");
+		goto err;
+	}
+
+	if (ofname == NULL) {
+		ERR("no output file specified");
+		goto err;
+	}
+
+	in = fopen(ifname, "r");
+	if (in == NULL) {
+		ERRS("could not open \"%s\" for reading: %s", ifname);
+		goto err;
+	}
+
+	buflen = board->imagelen;
+	kspace = buflen - HDR_LENGTH;
+
+	/* Get kernel length */
+	fseek(in, 0, SEEK_END);
+	klen = ftell(in);
+	rewind(in);
+
+	if (klen > kspace) {
+		ERR("file \"%s\" is too big - max size: 0x%08lX\n",
+		    ifname, kspace);
+		goto err_close_in;
+	}
+
+	/* If requested, resize buffer to remove padding */
+	if (strip_padding)
+		buflen = klen + HDR_LENGTH;
+
+	/* Allocate and initialize buffer for final image */
+	buf = malloc(buflen);
+	if (buf == NULL) {
+		ERRS("no memory for buffer: %s\n");
+		goto err_close_in;
+	}
+	memset(buf, PADDING_BYTE, buflen);
+
+	/* Load kernel */
+	kernel = buf + HDR_LENGTH;
+	fread(kernel, klen, 1, in);
+
+	/* Write magic values and filler */
+	writel(buf, HDR_OFF_MAGIC1, board->magic);
+	writel(buf, HDR_OFF_MAGIC2, board->magic);
+	writel(buf, HDR_OFF_FILLER, 0);
+
+	/* Write header and image length */
+	writel(buf, HDR_OFF_HDRLEN, HDR_LENGTH);
+	writel(buf, HDR_OFF_IMAGELEN, klen);
+
+	/* Write checksum and static hash */
+	sha1_csum(kernel, klen, buf + HDR_OFF_CHECKSUM);
+	memcpy(buf + HDR_OFF_STATICHASH, board->statichash, 20);
+
+	/* Save finished image */
+	out = fopen(ofname, "w");
+	if (out == NULL) {
+		ERRS("could not open \"%s\" for writing: %s", ofname);
+		goto err_free;
+	}
+	fwrite(buf, buflen, 1, out);
+
+	ret = EXIT_SUCCESS;
+
+	fclose(out);
+
+err_free:
+	free(buf);
+
+err_close_in:
+	fclose(in);
+
+err:
+	return ret;
+}