net/rose/rose_subr.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/types.h>
   8 #include <linux/socket.h>
   9 #include <linux/in.h>
  10 #include <linux/kernel.h>
  11 #include <linux/timer.h>
  12 #include <linux/string.h>
  13 #include <linux/sockios.h>
  14 #include <linux/net.h>
  15 #include <linux/slab.h>
  16 #include <net/ax25.h>
  17 #include <linux/inet.h>
  18 #include <linux/netdevice.h>
  19 #include <linux/skbuff.h>
  20 #include <net/sock.h>
  21 #include <net/tcp_states.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/mm.h>
  24 #include <linux/interrupt.h>
  25 #include <net/rose.h>
  26
  27 static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose);
  28
  29 /*
  30  *      This routine purges all of the queues of frames.
  31  */
  32 void rose_clear_queues(struct sock *sk)
  33 {
  34         skb_queue_purge(&sk->sk_write_queue);
  35         skb_queue_purge(&rose_sk(sk)->ack_queue);
  36 }
  37
  38 /*
  39  * This routine purges the input queue of those frames that have been
  40  * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
  41  * SDL diagram.
  42  */
  43 void rose_frames_acked(struct sock *sk, unsigned short nr)
  44 {
  45         struct sk_buff *skb;
  46         struct rose_sock *rose = rose_sk(sk);
  47
  48         /*
  49          * Remove all the ack-ed frames from the ack queue.
  50          */
  51         if (rose->va != nr) {
  52                 while (skb_peek(&rose->ack_queue) != NULL && rose->va != nr) {
  53                         skb = skb_dequeue(&rose->ack_queue);
  54                         kfree_skb(skb);
  55                         rose->va = (rose->va + 1) % ROSE_MODULUS;
  56                 }
  57         }
  58 }
  59
  60 void rose_requeue_frames(struct sock *sk)
  61 {
  62         struct sk_buff *skb, *skb_prev = NULL;
  63
  64         /*
  65          * Requeue all the un-ack-ed frames on the output queue to be picked
  66          * up by rose_kick. This arrangement handles the possibility of an
  67          * empty output queue.
  68          */
  69         while ((skb = skb_dequeue(&rose_sk(sk)->ack_queue)) != NULL) {
  70                 if (skb_prev == NULL)
  71                         skb_queue_head(&sk->sk_write_queue, skb);
  72                 else
  73                         skb_append(skb_prev, skb, &sk->sk_write_queue);
  74                 skb_prev = skb;
  75         }
  76 }
  77
  78 /*
  79  *      Validate that the value of nr is between va and vs. Return true or
  80  *      false for testing.
  81  */
  82 int rose_validate_nr(struct sock *sk, unsigned short nr)
  83 {
  84         struct rose_sock *rose = rose_sk(sk);
  85         unsigned short vc = rose->va;
  86
  87         while (vc != rose->vs) {
  88                 if (nr == vc) return 1;
  89                 vc = (vc + 1) % ROSE_MODULUS;
  90         }
  91
  92         return nr == rose->vs;
  93 }
  94
  95 /*
  96  *  This routine is called when the packet layer internally generates a
  97  *  control frame.
  98  */
  99 void rose_write_internal(struct sock *sk, int frametype)
 100 {
 101         struct rose_sock *rose = rose_sk(sk);
 102         struct sk_buff *skb;
 103         unsigned char  *dptr;
 104         unsigned char  lci1, lci2;
 105         int maxfaclen = 0;
 106         int len, faclen;
 107         int reserve;
 108
 109         reserve = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + 1;
 110         len = ROSE_MIN_LEN;
 111
 112         switch (frametype) {
 113         case ROSE_CALL_REQUEST:
 114                 len   += 1 + ROSE_ADDR_LEN + ROSE_ADDR_LEN;
 115                 maxfaclen = 256;
 116                 break;
 117         case ROSE_CALL_ACCEPTED:
 118         case ROSE_CLEAR_REQUEST:
 119         case ROSE_RESET_REQUEST:
 120                 len   += 2;
 121                 break;
 122         }
 123
 124         skb = alloc_skb(reserve + len + maxfaclen, GFP_ATOMIC);
 125         if (!skb)
 126                 return;
 127
 128         /*
 129          *      Space for AX.25 header and PID.
 130          */
 131         skb_reserve(skb, reserve);
 132
 133         dptr = skb_put(skb, len);
 134
 135         lci1 = (rose->lci >> 8) & 0x0F;
 136         lci2 = (rose->lci >> 0) & 0xFF;
 137
 138         switch (frametype) {
 139         case ROSE_CALL_REQUEST:
 140                 *dptr++ = ROSE_GFI | lci1;
 141                 *dptr++ = lci2;
 142                 *dptr++ = frametype;
 143                 *dptr++ = ROSE_CALL_REQ_ADDR_LEN_VAL;
 144                 memcpy(dptr, &rose->dest_addr,  ROSE_ADDR_LEN);
 145                 dptr   += ROSE_ADDR_LEN;
 146                 memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN);
 147                 dptr   += ROSE_ADDR_LEN;
 148                 faclen = rose_create_facilities(dptr, rose);
 149                 skb_put(skb, faclen);
 150                 dptr   += faclen;
 151                 break;
 152
 153         case ROSE_CALL_ACCEPTED:
 154                 *dptr++ = ROSE_GFI | lci1;
 155                 *dptr++ = lci2;
 156                 *dptr++ = frametype;
 157                 *dptr++ = 0x00;         /* Address length */
 158                 *dptr++ = 0;            /* Facilities length */
 159                 break;
 160
 161         case ROSE_CLEAR_REQUEST:
 162                 *dptr++ = ROSE_GFI | lci1;
 163                 *dptr++ = lci2;
 164                 *dptr++ = frametype;
 165                 *dptr++ = rose->cause;
 166                 *dptr++ = rose->diagnostic;
 167                 break;
 168
 169         case ROSE_RESET_REQUEST:
 170                 *dptr++ = ROSE_GFI | lci1;
 171                 *dptr++ = lci2;
 172                 *dptr++ = frametype;
 173                 *dptr++ = ROSE_DTE_ORIGINATED;
 174                 *dptr++ = 0;
 175                 break;
 176
 177         case ROSE_RR:
 178         case ROSE_RNR:
 179                 *dptr++ = ROSE_GFI | lci1;
 180                 *dptr++ = lci2;
 181                 *dptr   = frametype;
 182                 *dptr++ |= (rose->vr << 5) & 0xE0;
 183                 break;
 184
 185         case ROSE_CLEAR_CONFIRMATION:
 186         case ROSE_RESET_CONFIRMATION:
 187                 *dptr++ = ROSE_GFI | lci1;
 188                 *dptr++ = lci2;
 189                 *dptr++  = frametype;
 190                 break;
 191
 192         default:
 193                 printk(KERN_ERR "ROSE: rose_write_internal - invalid frametype %02X\n", frametype);
 194                 kfree_skb(skb);
 195                 return;
 196         }
 197
 198         rose_transmit_link(skb, rose->neighbour);
 199 }
 200
 201 int rose_decode(struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
 202 {
 203         unsigned char *frame;
 204
 205         frame = skb->data;
 206
 207         *ns = *nr = *q = *d = *m = 0;
 208
 209         switch (frame[2]) {
 210         case ROSE_CALL_REQUEST:
 211         case ROSE_CALL_ACCEPTED:
 212         case ROSE_CLEAR_REQUEST:
 213         case ROSE_CLEAR_CONFIRMATION:
 214         case ROSE_RESET_REQUEST:
 215         case ROSE_RESET_CONFIRMATION:
 216                 return frame[2];
 217         default:
 218                 break;
 219         }
 220
 221         if ((frame[2] & 0x1F) == ROSE_RR  ||
 222             (frame[2] & 0x1F) == ROSE_RNR) {
 223                 *nr = (frame[2] >> 5) & 0x07;
 224                 return frame[2] & 0x1F;
 225         }
 226
 227         if ((frame[2] & 0x01) == ROSE_DATA) {
 228                 *q  = (frame[0] & ROSE_Q_BIT) == ROSE_Q_BIT;
 229                 *d  = (frame[0] & ROSE_D_BIT) == ROSE_D_BIT;
 230                 *m  = (frame[2] & ROSE_M_BIT) == ROSE_M_BIT;
 231                 *nr = (frame[2] >> 5) & 0x07;
 232                 *ns = (frame[2] >> 1) & 0x07;
 233                 return ROSE_DATA;
 234         }
 235
 236         return ROSE_ILLEGAL;
 237 }
 238
 239 static int rose_parse_national(unsigned char *p, struct rose_facilities_struct *facilities, int len)
 240 {
 241         unsigned char *pt;
 242         unsigned char l, lg, n = 0;
 243         int fac_national_digis_received = 0;
 244
 245         do {
 246                 switch (*p & 0xC0) {
 247                 case 0x00:
 248                         if (len < 2)
 249                                 return -1;
 250                         p   += 2;
 251                         n   += 2;
 252                         len -= 2;
 253                         break;
 254
 255                 case 0x40:
 256                         if (len < 3)
 257                                 return -1;
 258                         if (*p == FAC_NATIONAL_RAND)
 259                                 facilities->rand = ((p[1] << 8) & 0xFF00) + ((p[2] << 0) & 0x00FF);
 260                         p   += 3;
 261                         n   += 3;
 262                         len -= 3;
 263                         break;
 264
 265                 case 0x80:
 266                         if (len < 4)
 267                                 return -1;
 268                         p   += 4;
 269                         n   += 4;
 270                         len -= 4;
 271                         break;
 272
 273                 case 0xC0:
 274                         if (len < 2)
 275                                 return -1;
 276                         l = p[1];
 277                         if (len < 2 + l)
 278                                 return -1;
 279                         if (*p == FAC_NATIONAL_DEST_DIGI) {
 280                                 if (!fac_national_digis_received) {
 281                                         if (l < AX25_ADDR_LEN)
 282                                                 return -1;
 283                                         memcpy(&facilities->source_digis[0], p + 2, AX25_ADDR_LEN);
 284                                         facilities->source_ndigis = 1;
 285                                 }
 286                         }
 287                         else if (*p == FAC_NATIONAL_SRC_DIGI) {
 288                                 if (!fac_national_digis_received) {
 289                                         if (l < AX25_ADDR_LEN)
 290                                                 return -1;
 291                                         memcpy(&facilities->dest_digis[0], p + 2, AX25_ADDR_LEN);
 292                                         facilities->dest_ndigis = 1;
 293                                 }
 294                         }
 295                         else if (*p == FAC_NATIONAL_FAIL_CALL) {
 296                                 if (l < AX25_ADDR_LEN)
 297                                         return -1;
 298                                 memcpy(&facilities->fail_call, p + 2, AX25_ADDR_LEN);
 299                         }
 300                         else if (*p == FAC_NATIONAL_FAIL_ADD) {
 301                                 if (l < 1 + ROSE_ADDR_LEN)
 302                                         return -1;
 303                                 memcpy(&facilities->fail_addr, p + 3, ROSE_ADDR_LEN);
 304                         }
 305                         else if (*p == FAC_NATIONAL_DIGIS) {
 306                                 if (l % AX25_ADDR_LEN)
 307                                         return -1;
 308                                 fac_national_digis_received = 1;
 309                                 facilities->source_ndigis = 0;
 310                                 facilities->dest_ndigis   = 0;
 311                                 for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) {
 312                                         if (pt[6] & AX25_HBIT) {
 313                                                 if (facilities->dest_ndigis >= ROSE_MAX_DIGIS)
 314                                                         return -1;
 315                                                 memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN);
 316                                         } else {
 317                                                 if (facilities->source_ndigis >= ROSE_MAX_DIGIS)
 318                                                         return -1;
 319                                                 memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN);
 320                                         }
 321                                 }
 322                         }
 323                         p   += l + 2;
 324                         n   += l + 2;
 325                         len -= l + 2;
 326                         break;
 327                 }
 328         } while (*p != 0x00 && len > 0);
 329
 330         return n;
 331 }
 332
 333 static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *facilities, int len)
 334 {
 335         unsigned char l, n = 0;
 336         char callsign[11];
 337
 338         do {
 339                 switch (*p & 0xC0) {
 340                 case 0x00:
 341                         if (len < 2)
 342                                 return -1;
 343                         p   += 2;
 344                         n   += 2;
 345                         len -= 2;
 346                         break;
 347
 348                 case 0x40:
 349                         if (len < 3)
 350                                 return -1;
 351                         p   += 3;
 352                         n   += 3;
 353                         len -= 3;
 354                         break;
 355
 356                 case 0x80:
 357                         if (len < 4)
 358                                 return -1;
 359                         p   += 4;
 360                         n   += 4;
 361                         len -= 4;
 362                         break;
 363
 364                 case 0xC0:
 365                         if (len < 2)
 366                                 return -1;
 367                         l = p[1];
 368
 369                         /* Prevent overflows*/
 370                         if (l < 10 || l > 20)
 371                                 return -1;
 372
 373                         if (*p == FAC_CCITT_DEST_NSAP) {
 374                                 memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN);
 375                                 memcpy(callsign, p + 12,   l - 10);
 376                                 callsign[l - 10] = '\0';
 377                                 asc2ax(&facilities->source_call, callsign);
 378                         }
 379                         if (*p == FAC_CCITT_SRC_NSAP) {
 380                                 memcpy(&facilities->dest_addr, p + 7, ROSE_ADDR_LEN);
 381                                 memcpy(callsign, p + 12, l - 10);
 382                                 callsign[l - 10] = '\0';
 383                                 asc2ax(&facilities->dest_call, callsign);
 384                         }
 385                         p   += l + 2;
 386                         n   += l + 2;
 387                         len -= l + 2;
 388                         break;
 389                 }
 390         } while (*p != 0x00 && len > 0);
 391
 392         return n;
 393 }
 394
 395 int rose_parse_facilities(unsigned char *p, unsigned packet_len,
 396         struct rose_facilities_struct *facilities)
 397 {
 398         int facilities_len, len;
 399
 400         facilities_len = *p++;
 401
 402         if (facilities_len == 0 || (unsigned int)facilities_len > packet_len)
 403                 return 0;
 404
 405         while (facilities_len >= 3 && *p == 0x00) {
 406                 facilities_len--;
 407                 p++;
 408
 409                 switch (*p) {
 410                 case FAC_NATIONAL:              /* National */
 411                         len = rose_parse_national(p + 1, facilities, facilities_len - 1);
 412                         break;
 413
 414                 case FAC_CCITT:         /* CCITT */
 415                         len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1);
 416                         break;
 417
 418                 default:
 419                         printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p);
 420                         len = 1;
 421                         break;
 422                 }
 423
 424                 if (len < 0)
 425                         return 0;
 426                 if (WARN_ON(len >= facilities_len))
 427                         return 0;
 428                 facilities_len -= len + 1;
 429                 p += len + 1;
 430         }
 431
 432         return facilities_len == 0;
 433 }
 434
 435 static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose)
 436 {
 437         unsigned char *p = buffer + 1;
 438         char *callsign;
 439         char buf[11];
 440         int len, nb;
 441
 442         /* National Facilities */
 443         if (rose->rand != 0 || rose->source_ndigis == 1 || rose->dest_ndigis == 1) {
 444                 *p++ = 0x00;
 445                 *p++ = FAC_NATIONAL;
 446
 447                 if (rose->rand != 0) {
 448                         *p++ = FAC_NATIONAL_RAND;
 449                         *p++ = (rose->rand >> 8) & 0xFF;
 450                         *p++ = (rose->rand >> 0) & 0xFF;
 451                 }
 452
 453                 /* Sent before older facilities */
 454                 if ((rose->source_ndigis > 0) || (rose->dest_ndigis > 0)) {
 455                         int maxdigi = 0;
 456                         *p++ = FAC_NATIONAL_DIGIS;
 457                         *p++ = AX25_ADDR_LEN * (rose->source_ndigis + rose->dest_ndigis);
 458                         for (nb = 0 ; nb < rose->source_ndigis ; nb++) {
 459                                 if (++maxdigi >= ROSE_MAX_DIGIS)
 460                                         break;
 461                                 memcpy(p, &rose->source_digis[nb], AX25_ADDR_LEN);
 462                                 p[6] |= AX25_HBIT;
 463                                 p += AX25_ADDR_LEN;
 464                         }
 465                         for (nb = 0 ; nb < rose->dest_ndigis ; nb++) {
 466                                 if (++maxdigi >= ROSE_MAX_DIGIS)
 467                                         break;
 468                                 memcpy(p, &rose->dest_digis[nb], AX25_ADDR_LEN);
 469                                 p[6] &= ~AX25_HBIT;
 470                                 p += AX25_ADDR_LEN;
 471                         }
 472                 }
 473
 474                 /* For compatibility */
 475                 if (rose->source_ndigis > 0) {
 476                         *p++ = FAC_NATIONAL_SRC_DIGI;
 477                         *p++ = AX25_ADDR_LEN;
 478                         memcpy(p, &rose->source_digis[0], AX25_ADDR_LEN);
 479                         p   += AX25_ADDR_LEN;
 480                 }
 481
 482                 /* For compatibility */
 483                 if (rose->dest_ndigis > 0) {
 484                         *p++ = FAC_NATIONAL_DEST_DIGI;
 485                         *p++ = AX25_ADDR_LEN;
 486                         memcpy(p, &rose->dest_digis[0], AX25_ADDR_LEN);
 487                         p   += AX25_ADDR_LEN;
 488                 }
 489         }
 490
 491         *p++ = 0x00;
 492         *p++ = FAC_CCITT;
 493
 494         *p++ = FAC_CCITT_DEST_NSAP;
 495
 496         callsign = ax2asc(buf, &rose->dest_call);
 497
 498         *p++ = strlen(callsign) + 10;
 499         *p++ = (strlen(callsign) + 9) * 2;              /* ??? */
 500
 501         *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
 502         *p++ = ROSE_ADDR_LEN * 2;
 503         memcpy(p, &rose->dest_addr, ROSE_ADDR_LEN);
 504         p   += ROSE_ADDR_LEN;
 505
 506         memcpy(p, callsign, strlen(callsign));
 507         p   += strlen(callsign);
 508
 509         *p++ = FAC_CCITT_SRC_NSAP;
 510
 511         callsign = ax2asc(buf, &rose->source_call);
 512
 513         *p++ = strlen(callsign) + 10;
 514         *p++ = (strlen(callsign) + 9) * 2;              /* ??? */
 515
 516         *p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
 517         *p++ = ROSE_ADDR_LEN * 2;
 518         memcpy(p, &rose->source_addr, ROSE_ADDR_LEN);
 519         p   += ROSE_ADDR_LEN;
 520
 521         memcpy(p, callsign, strlen(callsign));
 522         p   += strlen(callsign);
 523
 524         len       = p - buffer;
 525         buffer[0] = len - 1;
 526
 527         return len;
 528 }
 529
 530 void rose_disconnect(struct sock *sk, int reason, int cause, int diagnostic)
 531 {
 532         struct rose_sock *rose = rose_sk(sk);
 533
 534         rose_stop_timer(sk);
 535         rose_stop_idletimer(sk);
 536
 537         rose_clear_queues(sk);
 538
 539         rose->lci   = 0;
 540         rose->state = ROSE_STATE_0;
 541
 542         if (cause != -1)
 543                 rose->cause = cause;
 544
 545         if (diagnostic != -1)
 546                 rose->diagnostic = diagnostic;
 547
 548         sk->sk_state     = TCP_CLOSE;
 549         sk->sk_err       = reason;
 550         sk->sk_shutdown |= SEND_SHUTDOWN;
 551
 552         if (!sock_flag(sk, SOCK_DEAD)) {
 553                 sk->sk_state_change(sk);
 554                 sock_set_flag(sk, SOCK_DEAD);
 555         }
 556 }