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1da177e4 LT |
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/sched.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 null address is defined as a callsign of all spaces with an | |
32 | * SSID of zero. | |
33 | */ | |
34 | ax25_address null_ax25_address = {{0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x00}}; | |
35 | ||
36 | /* | |
37 | * ax25 -> ascii conversion | |
38 | */ | |
f75268cd | 39 | char *ax2asc(char *buf, ax25_address *a) |
1da177e4 | 40 | { |
1da177e4 LT |
41 | char c, *s; |
42 | int n; | |
43 | ||
44 | for (n = 0, s = buf; n < 6; n++) { | |
45 | c = (a->ax25_call[n] >> 1) & 0x7F; | |
46 | ||
47 | if (c != ' ') *s++ = c; | |
48 | } | |
49 | ||
50 | *s++ = '-'; | |
51 | ||
52 | if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { | |
53 | *s++ = '1'; | |
54 | n -= 10; | |
55 | } | |
56 | ||
57 | *s++ = n + '0'; | |
58 | *s++ = '\0'; | |
59 | ||
60 | if (*buf == '\0' || *buf == '-') | |
61 | return "*"; | |
62 | ||
63 | return buf; | |
64 | ||
65 | } | |
66 | ||
67 | /* | |
68 | * ascii -> ax25 conversion | |
69 | */ | |
baed16a7 | 70 | void asc2ax(ax25_address *addr, char *callsign) |
1da177e4 | 71 | { |
1da177e4 LT |
72 | char *s; |
73 | int n; | |
74 | ||
75 | for (s = callsign, n = 0; n < 6; n++) { | |
76 | if (*s != '\0' && *s != '-') | |
baed16a7 | 77 | addr->ax25_call[n] = *s++; |
1da177e4 | 78 | else |
baed16a7 RB |
79 | addr->ax25_call[n] = ' '; |
80 | addr->ax25_call[n] <<= 1; | |
81 | addr->ax25_call[n] &= 0xFE; | |
1da177e4 LT |
82 | } |
83 | ||
84 | if (*s++ == '\0') { | |
baed16a7 RB |
85 | addr->ax25_call[6] = 0x00; |
86 | return; | |
1da177e4 LT |
87 | } |
88 | ||
baed16a7 | 89 | addr->ax25_call[6] = *s++ - '0'; |
1da177e4 LT |
90 | |
91 | if (*s != '\0') { | |
baed16a7 RB |
92 | addr->ax25_call[6] *= 10; |
93 | addr->ax25_call[6] += *s++ - '0'; | |
1da177e4 LT |
94 | } |
95 | ||
baed16a7 RB |
96 | addr->ax25_call[6] <<= 1; |
97 | addr->ax25_call[6] &= 0x1E; | |
1da177e4 LT |
98 | } |
99 | ||
100 | /* | |
101 | * Compare two ax.25 addresses | |
102 | */ | |
103 | int ax25cmp(ax25_address *a, ax25_address *b) | |
104 | { | |
105 | int ct = 0; | |
106 | ||
107 | while (ct < 6) { | |
108 | if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */ | |
109 | return 1; | |
110 | ct++; | |
111 | } | |
112 | ||
113 | if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */ | |
114 | return 0; | |
115 | ||
116 | return 2; /* Partial match */ | |
117 | } | |
118 | ||
119 | /* | |
120 | * Compare two AX.25 digipeater paths. | |
121 | */ | |
122 | int ax25digicmp(ax25_digi *digi1, ax25_digi *digi2) | |
123 | { | |
124 | int i; | |
125 | ||
126 | if (digi1->ndigi != digi2->ndigi) | |
127 | return 1; | |
128 | ||
129 | if (digi1->lastrepeat != digi2->lastrepeat) | |
130 | return 1; | |
131 | ||
132 | for (i = 0; i < digi1->ndigi; i++) | |
133 | if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0) | |
134 | return 1; | |
135 | ||
136 | return 0; | |
137 | } | |
138 | ||
139 | /* | |
140 | * Given an AX.25 address pull of to, from, digi list, command/response and the start of data | |
141 | * | |
142 | */ | |
143 | unsigned char *ax25_addr_parse(unsigned char *buf, int len, ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags, int *dama) | |
144 | { | |
145 | int d = 0; | |
146 | ||
147 | if (len < 14) return NULL; | |
148 | ||
149 | if (flags != NULL) { | |
150 | *flags = 0; | |
151 | ||
152 | if (buf[6] & AX25_CBIT) | |
153 | *flags = AX25_COMMAND; | |
154 | if (buf[13] & AX25_CBIT) | |
155 | *flags = AX25_RESPONSE; | |
156 | } | |
157 | ||
158 | if (dama != NULL) | |
159 | *dama = ~buf[13] & AX25_DAMA_FLAG; | |
160 | ||
161 | /* Copy to, from */ | |
162 | if (dest != NULL) | |
163 | memcpy(dest, buf + 0, AX25_ADDR_LEN); | |
164 | if (src != NULL) | |
165 | memcpy(src, buf + 7, AX25_ADDR_LEN); | |
166 | ||
167 | buf += 2 * AX25_ADDR_LEN; | |
168 | len -= 2 * AX25_ADDR_LEN; | |
169 | ||
170 | digi->lastrepeat = -1; | |
171 | digi->ndigi = 0; | |
172 | ||
173 | while (!(buf[-1] & AX25_EBIT)) { | |
174 | if (d >= AX25_MAX_DIGIS) return NULL; /* Max of 6 digis */ | |
175 | if (len < 7) return NULL; /* Short packet */ | |
176 | ||
177 | memcpy(&digi->calls[d], buf, AX25_ADDR_LEN); | |
178 | digi->ndigi = d + 1; | |
179 | ||
180 | if (buf[6] & AX25_HBIT) { | |
181 | digi->repeated[d] = 1; | |
182 | digi->lastrepeat = d; | |
183 | } else { | |
184 | digi->repeated[d] = 0; | |
185 | } | |
186 | ||
187 | buf += AX25_ADDR_LEN; | |
188 | len -= AX25_ADDR_LEN; | |
189 | d++; | |
190 | } | |
191 | ||
192 | return buf; | |
193 | } | |
194 | ||
195 | /* | |
196 | * Assemble an AX.25 header from the bits | |
197 | */ | |
198 | int ax25_addr_build(unsigned char *buf, ax25_address *src, ax25_address *dest, ax25_digi *d, int flag, int modulus) | |
199 | { | |
200 | int len = 0; | |
201 | int ct = 0; | |
202 | ||
203 | memcpy(buf, dest, AX25_ADDR_LEN); | |
204 | buf[6] &= ~(AX25_EBIT | AX25_CBIT); | |
205 | buf[6] |= AX25_SSSID_SPARE; | |
206 | ||
207 | if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT; | |
208 | ||
209 | buf += AX25_ADDR_LEN; | |
210 | len += AX25_ADDR_LEN; | |
211 | ||
212 | memcpy(buf, src, AX25_ADDR_LEN); | |
213 | buf[6] &= ~(AX25_EBIT | AX25_CBIT); | |
214 | buf[6] &= ~AX25_SSSID_SPARE; | |
215 | ||
216 | if (modulus == AX25_MODULUS) | |
217 | buf[6] |= AX25_SSSID_SPARE; | |
218 | else | |
219 | buf[6] |= AX25_ESSID_SPARE; | |
220 | ||
221 | if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT; | |
222 | ||
223 | /* | |
224 | * Fast path the normal digiless path | |
225 | */ | |
226 | if (d == NULL || d->ndigi == 0) { | |
227 | buf[6] |= AX25_EBIT; | |
228 | return 2 * AX25_ADDR_LEN; | |
229 | } | |
230 | ||
231 | buf += AX25_ADDR_LEN; | |
232 | len += AX25_ADDR_LEN; | |
233 | ||
234 | while (ct < d->ndigi) { | |
235 | memcpy(buf, &d->calls[ct], AX25_ADDR_LEN); | |
236 | ||
237 | if (d->repeated[ct]) | |
238 | buf[6] |= AX25_HBIT; | |
239 | else | |
240 | buf[6] &= ~AX25_HBIT; | |
241 | ||
242 | buf[6] &= ~AX25_EBIT; | |
243 | buf[6] |= AX25_SSSID_SPARE; | |
244 | ||
245 | buf += AX25_ADDR_LEN; | |
246 | len += AX25_ADDR_LEN; | |
247 | ct++; | |
248 | } | |
249 | ||
250 | buf[-1] |= AX25_EBIT; | |
251 | ||
252 | return len; | |
253 | } | |
254 | ||
255 | int ax25_addr_size(ax25_digi *dp) | |
256 | { | |
257 | if (dp == NULL) | |
258 | return 2 * AX25_ADDR_LEN; | |
259 | ||
260 | return AX25_ADDR_LEN * (2 + dp->ndigi); | |
261 | } | |
262 | ||
263 | /* | |
264 | * Reverse Digipeat List. May not pass both parameters as same struct | |
265 | */ | |
266 | void ax25_digi_invert(ax25_digi *in, ax25_digi *out) | |
267 | { | |
268 | int ct; | |
269 | ||
270 | out->ndigi = in->ndigi; | |
271 | out->lastrepeat = in->ndigi - in->lastrepeat - 2; | |
272 | ||
273 | /* Invert the digipeaters */ | |
274 | for (ct = 0; ct < in->ndigi; ct++) { | |
275 | out->calls[ct] = in->calls[in->ndigi - ct - 1]; | |
276 | ||
277 | if (ct <= out->lastrepeat) { | |
278 | out->calls[ct].ax25_call[6] |= AX25_HBIT; | |
279 | out->repeated[ct] = 1; | |
280 | } else { | |
281 | out->calls[ct].ax25_call[6] &= ~AX25_HBIT; | |
282 | out->repeated[ct] = 0; | |
283 | } | |
284 | } | |
285 | } | |
286 |