OpenWrt – Blame information for rev 4

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4 office 1 /*
2 * MAC address manupulation utility
3 *
4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 *
10 */
11  
12 #include <errno.h>
13 #include <stdlib.h>
14 #include <stdio.h>
15 #include <stdint.h>
16 #include <string.h>
17 #include <unistd.h>
18  
19 #define MAC_ADDRESS_LEN 6
20  
21 #define ERR_INVALID 1
22 #define ERR_IO 2
23  
24 static void usage(void);
25  
26 char *maccalc_name;
27  
28 static int parse_mac(const char *mac_str, unsigned char *buf)
29 {
30 int t;
31  
32 t = sscanf(mac_str, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
33 &buf[0], &buf[1], &buf[2], &buf[3], &buf[4], &buf[5]);
34  
35 if (t != MAC_ADDRESS_LEN)
36 return ERR_INVALID;
37  
38 return 0;
39 }
40  
41 static void print_mac(unsigned char *buf)
42 {
43 printf("%02x:%02x:%02x:%02x:%02x:%02x\n",
44 buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
45 }
46  
47 static int maccalc_do_add(int argc, const char *argv[])
48 {
49 unsigned char mac[MAC_ADDRESS_LEN];
50 uint32_t t;
51 int err;
52 int i;
53  
54 if (argc != 2) {
55 usage();
56 return ERR_INVALID;
57 }
58  
59 err = parse_mac(argv[0], mac);
60 if (err)
61 return err;
62  
63 i = atoi(argv[1]);
64  
65 t = (mac[3] << 16) | (mac[4] << 8) | mac[5];
66 t += i;
67 mac[3] = (t >> 16) & 0xff;
68 mac[4] = (t >> 8) & 0xff;
69 mac[5] = t & 0xff;
70  
71 print_mac(mac);
72 return 0;
73 }
74  
75 static int maccalc_do_logical(int argc, const char *argv[],
76 unsigned char (*op)(unsigned char n1,
77 unsigned char n2))
78 {
79 unsigned char mac1[MAC_ADDRESS_LEN];
80 unsigned char mac2[MAC_ADDRESS_LEN];
81 int err;
82 int i;
83  
84 if (argc != 2) {
85 usage();
86 return ERR_INVALID;
87 }
88  
89 err = parse_mac(argv[0], mac1);
90 if (err)
91 return err;
92  
93 err = parse_mac(argv[1], mac2);
94 if (err)
95 return err;
96  
97 for (i = 0; i < MAC_ADDRESS_LEN; i++)
98 mac1[i] = op(mac1[i],mac2[i]);
99  
100 print_mac(mac1);
101 return 0;
102 }
103  
104 static int maccalc_do_mac2bin(int argc, const char *argv[])
105 {
106 unsigned char mac[MAC_ADDRESS_LEN];
107 ssize_t c;
108 int err;
109  
110 if (argc != 1) {
111 usage();
112 return ERR_INVALID;
113 }
114  
115 err = parse_mac(argv[0], mac);
116 if (err)
117 return err;
118  
119 c = write(STDOUT_FILENO, mac, sizeof(mac));
120 if (c != sizeof(mac)) {
121 fprintf(stderr, "failed to write to stdout\n");
122 return ERR_IO;
123 }
124  
125 return 0;
126 }
127  
128 static ssize_t read_safe(int fd, void *buf, size_t count)
129 {
130 ssize_t total = 0;
131 ssize_t r;
132  
133 while(count > 0) {
134 r = read(fd, buf, count);
135 if (r == 0)
136 /* EOF */
137 break;
138 if (r < 0) {
139 if (errno == EINTR)
140 /* interrupted by a signal, restart */
141 continue;
142 /* error */
143 total = -1;
144 break;
145 }
146  
147 /* ok */
148 total += r;
149 count -= r;
150 buf += r;
151 }
152  
153 return total;
154 }
155  
156 static int maccalc_do_bin2mac(int argc, const char *argv[])
157 {
158 unsigned char mac[MAC_ADDRESS_LEN];
159 ssize_t c;
160  
161 if (argc != 0) {
162 usage();
163 return ERR_INVALID;
164 }
165  
166 c = read_safe(STDIN_FILENO, mac, sizeof(mac));
167 if (c != sizeof(mac)) {
168 fprintf(stderr, "failed to read from stdin\n");
169 return ERR_IO;
170 }
171  
172 print_mac(mac);
173 return 0;
174 }
175  
176 static unsigned char op_or(unsigned char n1, unsigned char n2)
177 {
178 return n1 | n2;
179 }
180  
181 static int maccalc_do_or(int argc, const char *argv[])
182 {
183 return maccalc_do_logical(argc, argv, op_or);
184 }
185  
186 static unsigned char op_and(unsigned char n1, unsigned char n2)
187 {
188 return n1 & n2;
189 }
190  
191 static int maccalc_do_and(int argc, const char *argv[])
192 {
193 return maccalc_do_logical(argc, argv, op_and);
194 }
195  
196 static unsigned char op_xor(unsigned char n1, unsigned char n2)
197 {
198 return n1 ^ n2;
199 }
200  
201 static int maccalc_do_xor(int argc, const char *argv[])
202 {
203 return maccalc_do_logical(argc, argv, op_xor);
204 }
205  
206 static void usage(void)
207 {
208 fprintf(stderr,
209 "Usage: %s <command>\n"
210 "valid commands:\n"
211 " add <mac> <number>\n"
212 " and|or|xor <mac1> <mac2>\n"
213 " mac2bin <mac>\n"
214 " bin2mac\n",
215 maccalc_name);
216 }
217  
218 int main(int argc, const char *argv[])
219 {
220 int (*op)(int argc, const char *argv[]);
221 int ret;
222  
223 maccalc_name = (char *) argv[0];
224  
225 if (argc < 2) {
226 usage();
227 return EXIT_FAILURE;
228 }
229  
230 if (strcmp(argv[1], "add") == 0) {
231 op = maccalc_do_add;
232 } else if (strcmp(argv[1], "and") == 0) {
233 op = maccalc_do_and;
234 } else if (strcmp(argv[1], "or") == 0) {
235 op = maccalc_do_or;
236 } else if (strcmp(argv[1], "xor") == 0) {
237 op = maccalc_do_xor;
238 } else if (strcmp(argv[1], "mac2bin") == 0) {
239 op = maccalc_do_mac2bin;
240 } else if (strcmp(argv[1], "bin2mac") == 0) {
241 op = maccalc_do_bin2mac;
242 } else {
243 fprintf(stderr, "unknown command '%s'\n", argv[1]);
244 usage();
245 return EXIT_FAILURE;
246 }
247  
248 argc -= 2;
249 argv += 2;
250  
251 ret = op(argc, argv);
252 if (ret)
253 return EXIT_FAILURE;
254  
255 return EXIT_SUCCESS;
256 }