1 /*
2  * motorola-bin.c
3  *
4  * Copyright (C) 2005-2006 Mike Baker,
5  *                         Imre Kaloz <kaloz@openwrt.org>
6  *                         D. Hugh Redelmeier
7  *                         OpenWrt.org
8  *
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License
12  * as published by the Free Software Foundation; either version 2
13  * of the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
23  *
24  */
25 
26 /*
27  * Motorola's firmware flashing code requires an extra header.
28  * The header is eight bytes (see struct motorola below).
29  * This program will take a firmware file and create a new one
30  * with this header:
31  *	motorola-bin --wr850g WR850G_V403.stripped.trx WR850G_V403.trx
32  *
33  * Note: Motorola's firmware is distributed with this header.
34  * If you need to flash Motorola firmware on a router running OpenWRT,
35  * you will to remove this header.  Use the --strip flag:
36  *	motorola-bin --strip WR850G_V403.trx WR850G_V403.stripped.trx
37  */
38 
39 /*
40  * February 1, 2006
41  *
42  * Add support for for creating WA840G and WE800G images
43  */
44 
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <stddef.h>
48 #include <unistd.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <sys/mman.h>
52 #include <string.h>
53 #include <netinet/in.h>
54 #include <inttypes.h>
55 
56 #define BPB 8 /* bits/byte */
57 
58 static uint32_t crc32[1<<BPB];
59 
init_crc32()60 static void init_crc32()
61 {
62 	const uint32_t poly = ntohl(0x2083b8ed);
63 	int n;
64 
65 	for (n = 0; n < 1<<BPB; n++) {
66 		uint32_t crc = n;
67 		int bit;
68 
69 		for (bit = 0; bit < BPB; bit++)
70 			crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1);
71 		crc32[n] = crc;
72 	}
73 }
74 
crc32buf(unsigned char * buf,size_t len)75 static uint32_t crc32buf(unsigned char *buf, size_t len)
76 {
77 	uint32_t crc = 0xFFFFFFFF;
78 
79 	for (; len; len--, buf++)
80 		crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB);
81 	return crc;
82 }
83 
84 struct motorola {
85 	uint32_t crc;	// crc32 of the remainder
86 	uint32_t flags;	// unknown, 105770*
87 };
88 
89 static const struct model {
90 	char digit;	/* a digit signifying model (historical) */
91 	const char *name;
92 	uint32_t flags;
93 } models[] = {
94 	{ '1', "WR850G", 0x10577050LU },
95 	{ '2', "WA840G", 0x10577040LU },
96 	{ '3', "WE800G", 0x10577000LU },
97 	{ '\0', NULL, 0 }
98 };
99 
100 static void usage(const char *) __attribute__ (( __noreturn__ ));
101 
usage(const char * mess)102 static void usage(const char *mess)
103 {
104 	const struct model *m;
105 
106 	fprintf(stderr, "Error: %s\n", mess);
107 	fprintf(stderr, "Usage: motorola-bin -device|--strip infile outfile\n");
108 	fprintf(stderr, "Known devices: ");
109 
110 	for (m = models; m->digit != '\0'; m++)
111 		fprintf(stderr, " %c - %s", m->digit, m->name);
112 
113 	fprintf(stderr, "\n");
114 	exit(1);
115 }
116 
main(int argc,char ** argv)117 int main(int argc, char **argv)
118 {
119 	off_t len;	// of original firmware
120 	int fd;
121 	void *trx;	// pointer to original firmware (mmmapped)
122 	struct motorola *firmware;	// pionter to prefix + copy of original firmware
123 	uint32_t flags;
124 
125 	// verify parameters
126 
127 	if (argc != 4)
128 		usage("wrong number of arguments");
129 
130 	// mmap trx file
131 	if ((fd = open(argv[2], O_RDONLY))  < 0
132 	|| (len = lseek(fd, 0, SEEK_END)) < 0
133 	|| (trx = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1)
134 	|| close(fd) < 0)
135 	{
136 		fprintf(stderr, "Error loading file %s: %s\n", argv[2], strerror(errno));
137 		exit(1);
138 	}
139 
140 	init_crc32();
141 
142 	if (strcmp(argv[1], "--strip") == 0)
143 	{
144 		const char *ugh = NULL;
145 
146 		if (len < sizeof(struct motorola)) {
147 			ugh = "input file too short";
148 		} else {
149 			const struct model *m;
150 
151 			firmware = trx;
152 			if (htonl(crc32buf(trx + offsetof(struct motorola, flags), len - offsetof(struct motorola, flags))) != firmware->crc)
153 				ugh = "Invalid CRC";
154 			for (m = models; ; m++) {
155 				if (m->digit == '\0') {
156 					if (ugh == NULL)
157 						ugh = "unrecognized flags field";
158 					break;
159 				}
160 				if (firmware->flags == htonl(m->flags)) {
161 					fprintf(stderr, "Firmware for Motorola %s\n", m->name);
162 					break;
163 				}
164 			}
165 		}
166 
167 		if (ugh != NULL) {
168 			fprintf(stderr, "%s\n", ugh);
169 			exit(3);
170 		} else {
171 			// all is well, write the file without the prefix
172 			if ((fd = open(argv[3], O_CREAT|O_WRONLY|O_TRUNC,0644)) < 0
173 			|| write(fd, trx + sizeof(struct motorola), len - sizeof(struct motorola)) !=  len - sizeof(struct motorola)
174 			|| close(fd) < 0)
175 			{
176 				fprintf(stderr, "Error storing file %s: %s\n", argv[3], strerror(errno));
177 				exit(2);
178 			}
179 		}
180 
181 	} else {
182 		// setup the firmware flags magic number
183 		const struct model *m;
184 		const char *df = argv[1];
185 
186 		if (*df != '-')
187 			usage("first argument must start with -");
188 		if (*++df == '-')
189 			++df;	/* allow but don't require second - */
190 
191 		for (m = models; ; m++) {
192 			if (m->digit == '\0')
193 				usage("unrecognized device specified");
194 			if ((df[0] == m->digit && df[1] == '\0') || strcasecmp(df, m->name) == 0) {
195 				flags = m->flags;
196 				break;
197 			}
198 		}
199 
200 
201 		// create a firmware image in memory
202 		// and copy the trx to it
203 		firmware = malloc(sizeof(struct motorola) + len);
204 		memcpy(&firmware[1], trx, len);
205 
206 		// setup the motorola headers
207 		firmware->flags = htonl(flags);
208 
209 		// CRC of flags + firmware
210 		firmware->crc = htonl(crc32buf((unsigned char *)&firmware->flags, sizeof(firmware->flags) + len));
211 
212 		// write the firmware
213 		if ((fd = open(argv[3], O_CREAT|O_WRONLY|O_TRUNC,0644)) < 0
214 		|| write(fd, firmware, sizeof(struct motorola) + len) != sizeof(struct motorola) + len
215 		|| close(fd) < 0)
216 		{
217 			fprintf(stderr, "Error storing file %s: %s\n", argv[3], strerror(errno));
218 			exit(2);
219 		}
220 
221 		free(firmware);
222 	}
223 
224 	munmap(trx,len);
225 
226 	return 0;
227 }
228