[NETROM/AX.25/ROSE]: Remove useless tests
[linux-3.10.git] / net / rose / rose_subr.c
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 <net/tcp_states.h>
25 #include <asm/system.h>
26 #include <linux/fcntl.h>
27 #include <linux/mm.h>
28 #include <linux/interrupt.h>
29 #include <net/rose.h>
30
31 static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose);
32
33 /*
34  *      This routine purges all of the queues of frames.
35  */
36 void rose_clear_queues(struct sock *sk)
37 {
38         skb_queue_purge(&sk->sk_write_queue);
39         skb_queue_purge(&rose_sk(sk)->ack_queue);
40 }
41
42 /*
43  * This routine purges the input queue of those frames that have been
44  * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
45  * SDL diagram.
46  */
47 void rose_frames_acked(struct sock *sk, unsigned short nr)
48 {
49         struct sk_buff *skb;
50         struct rose_sock *rose = rose_sk(sk);
51
52         /*
53          * Remove all the ack-ed frames from the ack queue.
54          */
55         if (rose->va != nr) {
56                 while (skb_peek(&rose->ack_queue) != NULL && rose->va != nr) {
57                         skb = skb_dequeue(&rose->ack_queue);
58                         kfree_skb(skb);
59                         rose->va = (rose->va + 1) % ROSE_MODULUS;
60                 }
61         }
62 }
63
64 void rose_requeue_frames(struct sock *sk)
65 {
66         struct sk_buff *skb, *skb_prev = NULL;
67
68         /*
69          * Requeue all the un-ack-ed frames on the output queue to be picked
70          * up by rose_kick. This arrangement handles the possibility of an
71          * empty output queue.
72          */
73         while ((skb = skb_dequeue(&rose_sk(sk)->ack_queue)) != NULL) {
74                 if (skb_prev == NULL)
75                         skb_queue_head(&sk->sk_write_queue, skb);
76                 else
77                         skb_append(skb_prev, skb, &sk->sk_write_queue);
78                 skb_prev = skb;
79         }
80 }
81
82 /*
83  *      Validate that the value of nr is between va and vs. Return true or
84  *      false for testing.
85  */
86 int rose_validate_nr(struct sock *sk, unsigned short nr)
87 {
88         struct rose_sock *rose = rose_sk(sk);
89         unsigned short vc = rose->va;
90
91         while (vc != rose->vs) {
92                 if (nr == vc) return 1;
93                 vc = (vc + 1) % ROSE_MODULUS;
94         }
95
96         return nr == rose->vs;
97 }
98
99 /*
100  *  This routine is called when the packet layer internally generates a
101  *  control frame.
102  */
103 void rose_write_internal(struct sock *sk, int frametype)
104 {
105         struct rose_sock *rose = rose_sk(sk);
106         struct sk_buff *skb;
107         unsigned char  *dptr;
108         unsigned char  lci1, lci2;
109         char buffer[100];
110         int len, faclen = 0;
111
112         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
113
114         switch (frametype) {
115         case ROSE_CALL_REQUEST:
116                 len   += 1 + ROSE_ADDR_LEN + ROSE_ADDR_LEN;
117                 faclen = rose_create_facilities(buffer, rose);
118                 len   += faclen;
119                 break;
120         case ROSE_CALL_ACCEPTED:
121         case ROSE_CLEAR_REQUEST:
122         case ROSE_RESET_REQUEST:
123                 len   += 2;
124                 break;
125         }
126
127         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
128                 return;
129
130         /*
131          *      Space for AX.25 header and PID.
132          */
133         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + 1);
134
135         dptr = skb_put(skb, skb_tailroom(skb));
136
137         lci1 = (rose->lci >> 8) & 0x0F;
138         lci2 = (rose->lci >> 0) & 0xFF;
139
140         switch (frametype) {
141         case ROSE_CALL_REQUEST:
142                 *dptr++ = ROSE_GFI | lci1;
143                 *dptr++ = lci2;
144                 *dptr++ = frametype;
145                 *dptr++ = 0xAA;
146                 memcpy(dptr, &rose->dest_addr,  ROSE_ADDR_LEN);
147                 dptr   += ROSE_ADDR_LEN;
148                 memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN);
149                 dptr   += ROSE_ADDR_LEN;
150                 memcpy(dptr, buffer, faclen);
151                 dptr   += faclen;
152                 break;
153
154         case ROSE_CALL_ACCEPTED:
155                 *dptr++ = ROSE_GFI | lci1;
156                 *dptr++ = lci2;
157                 *dptr++ = frametype;
158                 *dptr++ = 0x00;         /* Address length */
159                 *dptr++ = 0;            /* Facilities length */
160                 break;
161
162         case ROSE_CLEAR_REQUEST:
163                 *dptr++ = ROSE_GFI | lci1;
164                 *dptr++ = lci2;
165                 *dptr++ = frametype;
166                 *dptr++ = rose->cause;
167                 *dptr++ = rose->diagnostic;
168                 break;
169
170         case ROSE_RESET_REQUEST:
171                 *dptr++ = ROSE_GFI | lci1;
172                 *dptr++ = lci2;
173                 *dptr++ = frametype;
174                 *dptr++ = ROSE_DTE_ORIGINATED;
175                 *dptr++ = 0;
176                 break;
177
178         case ROSE_RR:
179         case ROSE_RNR:
180                 *dptr++ = ROSE_GFI | lci1;
181                 *dptr++ = lci2;
182                 *dptr   = frametype;
183                 *dptr++ |= (rose->vr << 5) & 0xE0;
184                 break;
185
186         case ROSE_CLEAR_CONFIRMATION:
187         case ROSE_RESET_CONFIRMATION:
188                 *dptr++ = ROSE_GFI | lci1;
189                 *dptr++ = lci2;
190                 *dptr++  = frametype;
191                 break;
192
193         default:
194                 printk(KERN_ERR "ROSE: rose_write_internal - invalid frametype %02X\n", frametype);
195                 kfree_skb(skb);
196                 return;
197         }
198
199         rose_transmit_link(skb, rose->neighbour);
200 }
201
202 int rose_decode(struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
203 {
204         unsigned char *frame;
205
206         frame = skb->data;
207
208         *ns = *nr = *q = *d = *m = 0;
209
210         switch (frame[2]) {
211         case ROSE_CALL_REQUEST:
212         case ROSE_CALL_ACCEPTED:
213         case ROSE_CLEAR_REQUEST:
214         case ROSE_CLEAR_CONFIRMATION:
215         case ROSE_RESET_REQUEST:
216         case ROSE_RESET_CONFIRMATION:
217                 return frame[2];
218         default:
219                 break;
220         }
221
222         if ((frame[2] & 0x1F) == ROSE_RR  ||
223             (frame[2] & 0x1F) == ROSE_RNR) {
224                 *nr = (frame[2] >> 5) & 0x07;
225                 return frame[2] & 0x1F;
226         }
227
228         if ((frame[2] & 0x01) == ROSE_DATA) {
229                 *q  = (frame[0] & ROSE_Q_BIT) == ROSE_Q_BIT;
230                 *d  = (frame[0] & ROSE_D_BIT) == ROSE_D_BIT;
231                 *m  = (frame[2] & ROSE_M_BIT) == ROSE_M_BIT;
232                 *nr = (frame[2] >> 5) & 0x07;
233                 *ns = (frame[2] >> 1) & 0x07;
234                 return ROSE_DATA;
235         }
236
237         return ROSE_ILLEGAL;
238 }
239
240 static int rose_parse_national(unsigned char *p, struct rose_facilities_struct *facilities, int len)
241 {
242         unsigned char *pt;
243         unsigned char l, lg, n = 0;
244         int fac_national_digis_received = 0;
245
246         do {
247                 switch (*p & 0xC0) {
248                 case 0x00:
249                         p   += 2;
250                         n   += 2;
251                         len -= 2;
252                         break;
253
254                 case 0x40:
255                         if (*p == FAC_NATIONAL_RAND)
256                                 facilities->rand = ((p[1] << 8) & 0xFF00) + ((p[2] << 0) & 0x00FF);
257                         p   += 3;
258                         n   += 3;
259                         len -= 3;
260                         break;
261
262                 case 0x80:
263                         p   += 4;
264                         n   += 4;
265                         len -= 4;
266                         break;
267
268                 case 0xC0:
269                         l = p[1];
270                         if (*p == FAC_NATIONAL_DEST_DIGI) {
271                                 if (!fac_national_digis_received) {
272                                         memcpy(&facilities->source_digis[0], p + 2, AX25_ADDR_LEN);
273                                         facilities->source_ndigis = 1;
274                                 }
275                         }
276                         else if (*p == FAC_NATIONAL_SRC_DIGI) {
277                                 if (!fac_national_digis_received) {
278                                         memcpy(&facilities->dest_digis[0], p + 2, AX25_ADDR_LEN);
279                                         facilities->dest_ndigis = 1;
280                                 }
281                         }
282                         else if (*p == FAC_NATIONAL_FAIL_CALL) {
283                                 memcpy(&facilities->fail_call, p + 2, AX25_ADDR_LEN);
284                         }
285                         else if (*p == FAC_NATIONAL_FAIL_ADD) {
286                                 memcpy(&facilities->fail_addr, p + 3, ROSE_ADDR_LEN);
287                         }
288                         else if (*p == FAC_NATIONAL_DIGIS) {
289                                 fac_national_digis_received = 1;
290                                 facilities->source_ndigis = 0;
291                                 facilities->dest_ndigis   = 0;
292                                 for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) {
293                                         if (pt[6] & AX25_HBIT)
294                                                 memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN);
295                                         else
296                                                 memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN);
297                                 }
298                         }
299                         p   += l + 2;
300                         n   += l + 2;
301                         len -= l + 2;
302                         break;
303                 }
304         } while (*p != 0x00 && len > 0);
305
306         return n;
307 }
308
309 static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *facilities, int len)
310 {
311         unsigned char l, n = 0;
312         char callsign[11];
313
314         do {
315                 switch (*p & 0xC0) {
316                 case 0x00:
317                         p   += 2;
318                         n   += 2;
319                         len -= 2;
320                         break;
321
322                 case 0x40:
323                         p   += 3;
324                         n   += 3;
325                         len -= 3;
326                         break;
327
328                 case 0x80:
329                         p   += 4;
330                         n   += 4;
331                         len -= 4;
332                         break;
333
334                 case 0xC0:
335                         l = p[1];
336                         if (*p == FAC_CCITT_DEST_NSAP) {
337                                 memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN);
338                                 memcpy(callsign, p + 12,   l - 10);
339                                 callsign[l - 10] = '\0';
340                                 asc2ax(&facilities->source_call, callsign);
341                         }
342                         if (*p == FAC_CCITT_SRC_NSAP) {
343                                 memcpy(&facilities->dest_addr, p + 7, ROSE_ADDR_LEN);
344                                 memcpy(callsign, p + 12, l - 10);
345                                 callsign[l - 10] = '\0';
346                                 asc2ax(&facilities->dest_call, callsign);
347                         }
348                         p   += l + 2;
349                         n   += l + 2;
350                         len -= l + 2;
351                         break;
352                 }
353         } while (*p != 0x00 && len > 0);
354
355         return n;
356 }
357
358 int rose_parse_facilities(unsigned char *p,
359         struct rose_facilities_struct *facilities)
360 {
361         int facilities_len, len;
362
363         facilities_len = *p++;
364
365         if (facilities_len == 0)
366                 return 0;
367
368         while (facilities_len > 0) {
369                 if (*p == 0x00) {
370                         facilities_len--;
371                         p++;
372
373                         switch (*p) {
374                         case FAC_NATIONAL:              /* National */
375                                 len = rose_parse_national(p + 1, facilities, facilities_len - 1);
376                                 facilities_len -= len + 1;
377                                 p += len + 1;
378                                 break;
379
380                         case FAC_CCITT:         /* CCITT */
381                                 len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1);
382                                 facilities_len -= len + 1;
383                                 p += len + 1;
384                                 break;
385
386                         default:
387                                 printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p);
388                                 facilities_len--;
389                                 p++;
390                                 break;
391                         }
392                 } else
393                         break;  /* Error in facilities format */
394         }
395
396         return 1;
397 }
398
399 static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose)
400 {
401         unsigned char *p = buffer + 1;
402         char *callsign;
403         char buf[11];
404         int len, nb;
405
406         /* National Facilities */
407         if (rose->rand != 0 || rose->source_ndigis == 1 || rose->dest_ndigis == 1) {
408                 *p++ = 0x00;
409                 *p++ = FAC_NATIONAL;
410
411                 if (rose->rand != 0) {
412                         *p++ = FAC_NATIONAL_RAND;
413                         *p++ = (rose->rand >> 8) & 0xFF;
414                         *p++ = (rose->rand >> 0) & 0xFF;
415                 }
416
417                 /* Sent before older facilities */
418                 if ((rose->source_ndigis > 0) || (rose->dest_ndigis > 0)) {
419                         int maxdigi = 0;
420                         *p++ = FAC_NATIONAL_DIGIS;
421                         *p++ = AX25_ADDR_LEN * (rose->source_ndigis + rose->dest_ndigis);
422                         for (nb = 0 ; nb < rose->source_ndigis ; nb++) {
423                                 if (++maxdigi >= ROSE_MAX_DIGIS)
424                                         break;
425                                 memcpy(p, &rose->source_digis[nb], AX25_ADDR_LEN);
426                                 p[6] |= AX25_HBIT;
427                                 p += AX25_ADDR_LEN;
428                         }
429                         for (nb = 0 ; nb < rose->dest_ndigis ; nb++) {
430                                 if (++maxdigi >= ROSE_MAX_DIGIS)
431                                         break;
432                                 memcpy(p, &rose->dest_digis[nb], AX25_ADDR_LEN);
433                                 p[6] &= ~AX25_HBIT;
434                                 p += AX25_ADDR_LEN;
435                         }
436                 }
437
438                 /* For compatibility */
439                 if (rose->source_ndigis > 0) {
440                         *p++ = FAC_NATIONAL_SRC_DIGI;
441                         *p++ = AX25_ADDR_LEN;
442                         memcpy(p, &rose->source_digis[0], AX25_ADDR_LEN);
443                         p   += AX25_ADDR_LEN;
444                 }
445
446                 /* For compatibility */
447                 if (rose->dest_ndigis > 0) {
448                         *p++ = FAC_NATIONAL_DEST_DIGI;
449                         *p++ = AX25_ADDR_LEN;
450                         memcpy(p, &rose->dest_digis[0], AX25_ADDR_LEN);
451                         p   += AX25_ADDR_LEN;
452                 }
453         }
454
455         *p++ = 0x00;
456         *p++ = FAC_CCITT;
457
458         *p++ = FAC_CCITT_DEST_NSAP;
459
460         callsign = ax2asc(buf, &rose->dest_call);
461
462         *p++ = strlen(callsign) + 10;
463         *p++ = (strlen(callsign) + 9) * 2;              /* ??? */
464
465         *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
466         *p++ = ROSE_ADDR_LEN * 2;
467         memcpy(p, &rose->dest_addr, ROSE_ADDR_LEN);
468         p   += ROSE_ADDR_LEN;
469
470         memcpy(p, callsign, strlen(callsign));
471         p   += strlen(callsign);
472
473         *p++ = FAC_CCITT_SRC_NSAP;
474
475         callsign = ax2asc(buf, &rose->source_call);
476
477         *p++ = strlen(callsign) + 10;
478         *p++ = (strlen(callsign) + 9) * 2;              /* ??? */
479
480         *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
481         *p++ = ROSE_ADDR_LEN * 2;
482         memcpy(p, &rose->source_addr, ROSE_ADDR_LEN);
483         p   += ROSE_ADDR_LEN;
484
485         memcpy(p, callsign, strlen(callsign));
486         p   += strlen(callsign);
487
488         len       = p - buffer;
489         buffer[0] = len - 1;
490
491         return len;
492 }
493
494 void rose_disconnect(struct sock *sk, int reason, int cause, int diagnostic)
495 {
496         struct rose_sock *rose = rose_sk(sk);
497
498         rose_stop_timer(sk);
499         rose_stop_idletimer(sk);
500
501         rose_clear_queues(sk);
502
503         rose->lci   = 0;
504         rose->state = ROSE_STATE_0;
505
506         if (cause != -1)
507                 rose->cause = cause;
508
509         if (diagnostic != -1)
510                 rose->diagnostic = diagnostic;
511
512         sk->sk_state     = TCP_CLOSE;
513         sk->sk_err       = reason;
514         sk->sk_shutdown |= SEND_SHUTDOWN;
515
516         if (!sock_flag(sk, SOCK_DEAD)) {
517                 sk->sk_state_change(sk);
518                 sock_set_flag(sk, SOCK_DEAD);
519         }
520 }