linux/net/rose/rose_subr.c
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   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/timer.h>
  15#include <linux/string.h>
  16#include <linux/sockios.h>
  17#include <linux/net.h>
  18#include <linux/slab.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 <linux/fcntl.h>
  26#include <linux/mm.h>
  27#include <linux/interrupt.h>
  28#include <net/rose.h>
  29
  30static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose);
  31
  32/*
  33 *      This routine purges all of the queues of frames.
  34 */
  35void rose_clear_queues(struct sock *sk)
  36{
  37        skb_queue_purge(&sk->sk_write_queue);
  38        skb_queue_purge(&rose_sk(sk)->ack_queue);
  39}
  40
  41/*
  42 * This routine purges the input queue of those frames that have been
  43 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
  44 * SDL diagram.
  45 */
  46void rose_frames_acked(struct sock *sk, unsigned short nr)
  47{
  48        struct sk_buff *skb;
  49        struct rose_sock *rose = rose_sk(sk);
  50
  51        /*
  52         * Remove all the ack-ed frames from the ack queue.
  53         */
  54        if (rose->va != nr) {
  55                while (skb_peek(&rose->ack_queue) != NULL && rose->va != nr) {
  56                        skb = skb_dequeue(&rose->ack_queue);
  57                        kfree_skb(skb);
  58                        rose->va = (rose->va + 1) % ROSE_MODULUS;
  59                }
  60        }
  61}
  62
  63void rose_requeue_frames(struct sock *sk)
  64{
  65        struct sk_buff *skb, *skb_prev = NULL;
  66
  67        /*
  68         * Requeue all the un-ack-ed frames on the output queue to be picked
  69         * up by rose_kick. This arrangement handles the possibility of an
  70         * empty output queue.
  71         */
  72        while ((skb = skb_dequeue(&rose_sk(sk)->ack_queue)) != NULL) {
  73                if (skb_prev == NULL)
  74                        skb_queue_head(&sk->sk_write_queue, skb);
  75                else
  76                        skb_append(skb_prev, skb, &sk->sk_write_queue);
  77                skb_prev = skb;
  78        }
  79}
  80
  81/*
  82 *      Validate that the value of nr is between va and vs. Return true or
  83 *      false for testing.
  84 */
  85int rose_validate_nr(struct sock *sk, unsigned short nr)
  86{
  87        struct rose_sock *rose = rose_sk(sk);
  88        unsigned short vc = rose->va;
  89
  90        while (vc != rose->vs) {
  91                if (nr == vc) return 1;
  92                vc = (vc + 1) % ROSE_MODULUS;
  93        }
  94
  95        return nr == rose->vs;
  96}
  97
  98/*
  99 *  This routine is called when the packet layer internally generates a
 100 *  control frame.
 101 */
 102void rose_write_internal(struct sock *sk, int frametype)
 103{
 104        struct rose_sock *rose = rose_sk(sk);
 105        struct sk_buff *skb;
 106        unsigned char  *dptr;
 107        unsigned char  lci1, lci2;
 108        char buffer[100];
 109        int len, faclen = 0;
 110
 111        len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
 112
 113        switch (frametype) {
 114        case ROSE_CALL_REQUEST:
 115                len   += 1 + ROSE_ADDR_LEN + ROSE_ADDR_LEN;
 116                faclen = rose_create_facilities(buffer, rose);
 117                len   += faclen;
 118                break;
 119        case ROSE_CALL_ACCEPTED:
 120        case ROSE_CLEAR_REQUEST:
 121        case ROSE_RESET_REQUEST:
 122                len   += 2;
 123                break;
 124        }
 125
 126        if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 127                return;
 128
 129        /*
 130         *      Space for AX.25 header and PID.
 131         */
 132        skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + 1);
 133
 134        dptr = skb_put(skb, skb_tailroom(skb));
 135
 136        lci1 = (rose->lci >> 8) & 0x0F;
 137        lci2 = (rose->lci >> 0) & 0xFF;
 138
 139        switch (frametype) {
 140        case ROSE_CALL_REQUEST:
 141                *dptr++ = ROSE_GFI | lci1;
 142                *dptr++ = lci2;
 143                *dptr++ = frametype;
 144                *dptr++ = ROSE_CALL_REQ_ADDR_LEN_VAL;
 145                memcpy(dptr, &rose->dest_addr,  ROSE_ADDR_LEN);
 146                dptr   += ROSE_ADDR_LEN;
 147                memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN);
 148                dptr   += ROSE_ADDR_LEN;
 149                memcpy(dptr, buffer, 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
 201int 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
 239static 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
 333static 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
 395int 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
 435static 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
 530void 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}
 557
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