1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 */
9 #include <linux/errno.h>
10 #include <linux/types.h>
11 #include <linux/socket.h>
12 #include <linux/in.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/timer.h>
16 #include <linux/string.h>
17 #include <linux/sockios.h>
18 #include <linux/net.h>
19 #include <net/ax25.h>
20 #include <linux/inet.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <net/sock.h>
24 #include <asm/uaccess.h>
25 #include <asm/system.h>
26 #include <linux/fcntl.h>
27 #include <linux/mm.h>
28 #include <linux/interrupt.h>
29
30 /*
31 * The default broadcast address of an interface is QST-0; the default address
32 * is LINUX-1. The null address is defined as a callsign of all spaces with
33 * an SSID of zero.
34 */
35
36 const ax25_address ax25_bcast =
37 {{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
38 const ax25_address ax25_defaddr =
39 {{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}};
40 const ax25_address null_ax25_address =
41 {{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
42
43 EXPORT_SYMBOL_GPL(ax25_bcast);
44 EXPORT_SYMBOL_GPL(ax25_defaddr);
45 EXPORT_SYMBOL(null_ax25_address);
46
47 /*
48 * ax25 -> ascii conversion
49 */
50 char *ax2asc(char *buf, const ax25_address *a)
51 {
52 char c, *s;
53 int n;
54
55 for (n = 0, s = buf; n < 6; n++) {
56 c = (a->ax25_call[n] >> 1) & 0x7F;
57
58 if (c != ' ') *s++ = c;
59 }
60
61 *s++ = '-';
62
63 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
64 *s++ = '1';
65 n -= 10;
66 }
67
68 *s++ = n + '';
69 *s++ = '\0';
70
71 if (*buf == '\0' || *buf == '-')
72 return "*";
73
74 return buf;
75
76 }
77
78 EXPORT_SYMBOL(ax2asc);
79
80 /*
81 * ascii -> ax25 conversion
82 */
83 void asc2ax(ax25_address *addr, const char *callsign)
84 {
85 const char *s;
86 int n;
87
88 for (s = callsign, n = 0; n < 6; n++) {
89 if (*s != '\0' && *s != '-')
90 addr->ax25_call[n] = *s++;
91 else
92 addr->ax25_call[n] = ' ';
93 addr->ax25_call[n] <<= 1;
94 addr->ax25_call[n] &= 0xFE;
95 }
96
97 if (*s++ == '\0') {
98 addr->ax25_call[6] = 0x00;
99 return;
100 }
101
102 addr->ax25_call[6] = *s++ - '';
103
104 if (*s != '\0') {
105 addr->ax25_call[6] *= 10;
106 addr->ax25_call[6] += *s++ - '';
107 }
108
109 addr->ax25_call[6] <<= 1;
110 addr->ax25_call[6] &= 0x1E;
111 }
112
113 EXPORT_SYMBOL(asc2ax);
114
115 /*
116 * Compare two ax.25 addresses
117 */
118 int ax25cmp(const ax25_address *a, const ax25_address *b)
119 {
120 int ct = 0;
121
122 while (ct < 6) {
123 if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */
124 return 1;
125 ct++;
126 }
127
128 if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */
129 return 0;
130
131 return 2; /* Partial match */
132 }
133
134 EXPORT_SYMBOL(ax25cmp);
135
136 /*
137 * Compare two AX.25 digipeater paths.
138 */
139 int ax25digicmp(const ax25_digi *digi1, const ax25_digi *digi2)
140 {
141 int i;
142
143 if (digi1->ndigi != digi2->ndigi)
144 return 1;
145
146 if (digi1->lastrepeat != digi2->lastrepeat)
147 return 1;
148
149 for (i = 0; i < digi1->ndigi; i++)
150 if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0)
151 return 1;
152
153 return 0;
154 }
155
156 /*
157 * Given an AX.25 address pull of to, from, digi list, command/response and the start of data
158 *
159 */
160 const unsigned char *ax25_addr_parse(const unsigned char *buf, int len,
161 ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags,
162 int *dama)
163 {
164 int d = 0;
165
166 if (len < 14) return NULL;
167
168 if (flags != NULL) {
169 *flags = 0;
170
171 if (buf[6] & AX25_CBIT)
172 *flags = AX25_COMMAND;
173 if (buf[13] & AX25_CBIT)
174 *flags = AX25_RESPONSE;
175 }
176
177 if (dama != NULL)
178 *dama = ~buf[13] & AX25_DAMA_FLAG;
179
180 /* Copy to, from */
181 if (dest != NULL)
182 memcpy(dest, buf + 0, AX25_ADDR_LEN);
183 if (src != NULL)
184 memcpy(src, buf + 7, AX25_ADDR_LEN);
185
186 buf += 2 * AX25_ADDR_LEN;
187 len -= 2 * AX25_ADDR_LEN;
188
189 digi->lastrepeat = -1;
190 digi->ndigi = 0;
191
192 while (!(buf[-1] & AX25_EBIT)) {
193 if (d >= AX25_MAX_DIGIS) return NULL; /* Max of 6 digis */
194 if (len < 7) return NULL; /* Short packet */
195
196 memcpy(&digi->calls[d], buf, AX25_ADDR_LEN);
197 digi->ndigi = d + 1;
198
199 if (buf[6] & AX25_HBIT) {
200 digi->repeated[d] = 1;
201 digi->lastrepeat = d;
202 } else {
203 digi->repeated[d] = 0;
204 }
205
206 buf += AX25_ADDR_LEN;
207 len -= AX25_ADDR_LEN;
208 d++;
209 }
210
211 return buf;
212 }
213
214 /*
215 * Assemble an AX.25 header from the bits
216 */
217 int ax25_addr_build(unsigned char *buf, const ax25_address *src,
218 const ax25_address *dest, const ax25_digi *d, int flag, int modulus)
219 {
220 int len = 0;
221 int ct = 0;
222
223 memcpy(buf, dest, AX25_ADDR_LEN);
224 buf[6] &= ~(AX25_EBIT | AX25_CBIT);
225 buf[6] |= AX25_SSSID_SPARE;
226
227 if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT;
228
229 buf += AX25_ADDR_LEN;
230 len += AX25_ADDR_LEN;
231
232 memcpy(buf, src, AX25_ADDR_LEN);
233 buf[6] &= ~(AX25_EBIT | AX25_CBIT);
234 buf[6] &= ~AX25_SSSID_SPARE;
235
236 if (modulus == AX25_MODULUS)
237 buf[6] |= AX25_SSSID_SPARE;
238 else
239 buf[6] |= AX25_ESSID_SPARE;
240
241 if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT;
242
243 /*
244 * Fast path the normal digiless path
245 */
246 if (d == NULL || d->ndigi == 0) {
247 buf[6] |= AX25_EBIT;
248 return 2 * AX25_ADDR_LEN;
249 }
250
251 buf += AX25_ADDR_LEN;
252 len += AX25_ADDR_LEN;
253
254 while (ct < d->ndigi) {
255 memcpy(buf, &d->calls[ct], AX25_ADDR_LEN);
256
257 if (d->repeated[ct])
258 buf[6] |= AX25_HBIT;
259 else
260 buf[6] &= ~AX25_HBIT;
261
262 buf[6] &= ~AX25_EBIT;
263 buf[6] |= AX25_SSSID_SPARE;
264
265 buf += AX25_ADDR_LEN;
266 len += AX25_ADDR_LEN;
267 ct++;
268 }
269
270 buf[-1] |= AX25_EBIT;
271
272 return len;
273 }
274
275 int ax25_addr_size(const ax25_digi *dp)
276 {
277 if (dp == NULL)
278 return 2 * AX25_ADDR_LEN;
279
280 return AX25_ADDR_LEN * (2 + dp->ndigi);
281 }
282
283 /*
284 * Reverse Digipeat List. May not pass both parameters as same struct
285 */
286 void ax25_digi_invert(const ax25_digi *in, ax25_digi *out)
287 {
288 int ct;
289
290 out->ndigi = in->ndigi;
291 out->lastrepeat = in->ndigi - in->lastrepeat - 2;
292
293 /* Invert the digipeaters */
294 for (ct = 0; ct < in->ndigi; ct++) {
295 out->calls[ct] = in->calls[in->ndigi - ct - 1];
296
297 if (ct <= out->lastrepeat) {
298 out->calls[ct].ax25_call[6] |= AX25_HBIT;
299 out->repeated[ct] = 1;
300 } else {
301 out->calls[ct].ax25_call[6] &= ~AX25_HBIT;
302 out->repeated[ct] = 0;
303 }
304 }
305 }
306
307
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