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