net/decnet/dn_nsp_in.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Network Services Protocol (Input)
   7  *
   8  * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>
   9  *
  10  * Changes:
  11  *
  12  *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from
  13  *                       original dn_nsp.c.
  14  *    Steve Whitehouse:  Updated to work with my new routing architecture.
  15  *    Steve Whitehouse:  Add changes from Eduardo Serrat's patches.
  16  *    Steve Whitehouse:  Put all ack handling code in a common routine.
  17  *    Steve Whitehouse:  Put other common bits into dn_nsp_rx()
  18  *    Steve Whitehouse:  More checks on skb->len to catch bogus packets
  19  *                       Fixed various race conditions and possible nasties.
  20  *    Steve Whitehouse:  Now handles returned conninit frames.
  21  *     David S. Miller:  New socket locking
  22  *    Steve Whitehouse:  Fixed lockup when socket filtering was enabled.
  23  *         Paul Koning:  Fix to push CC sockets into RUN when acks are
  24  *                       received.
  25  *    Steve Whitehouse:
  26  *   Patrick Caulfield:  Checking conninits for correctness & sending of error
  27  *                       responses.
  28  */
  29
  30 /******************************************************************************
  31     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  32
  33     This program is free software; you can redistribute it and/or modify
  34     it under the terms of the GNU General Public License as published by
  35     the Free Software Foundation; either version 2 of the License, or
  36     any later version.
  37
  38     This program is distributed in the hope that it will be useful,
  39     but WITHOUT ANY WARRANTY; without even the implied warranty of
  40     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  41     GNU General Public License for more details.
  42 *******************************************************************************/
  43
  44 #include <linux/config.h>
  45 #include <linux/errno.h>
  46 #include <linux/types.h>
  47 #include <linux/socket.h>
  48 #include <linux/in.h>
  49 #include <linux/kernel.h>
  50 #include <linux/sched.h>
  51 #include <linux/timer.h>
  52 #include <linux/string.h>
  53 #include <linux/sockios.h>
  54 #include <linux/net.h>
  55 #include <linux/netdevice.h>
  56 #include <linux/inet.h>
  57 #include <linux/route.h>
  58 #include <net/sock.h>
  59 #include <asm/segment.h>
  60 #include <asm/system.h>
  61 #include <linux/fcntl.h>
  62 #include <linux/mm.h>
  63 #include <linux/termios.h>
  64 #include <linux/interrupt.h>
  65 #include <linux/proc_fs.h>
  66 #include <linux/stat.h>
  67 #include <linux/init.h>
  68 #include <linux/poll.h>
  69 #include <linux/netfilter_decnet.h>
  70 #include <net/neighbour.h>
  71 #include <net/dst.h>
  72 #include <net/dn_nsp.h>
  73 #include <net/dn_dev.h>
  74 #include <net/dn_route.h>
  75
  76 extern int decnet_log_martians;
  77
  78 static void dn_log_martian(struct sk_buff *skb, const char *msg)
  79 {
  80         if (decnet_log_martians && net_ratelimit()) {
  81                 char *devname = skb->dev ? skb->dev->name : "???";
  82                 struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
  83                 printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n", msg, devname, cb->src, cb->dst, cb->src_port, cb->dst_port);
  84         }
  85 }
  86
  87 /*
  88  * For this function we've flipped the cross-subchannel bit
  89  * if the message is an otherdata or linkservice message. Thus
  90  * we can use it to work out what to update.
  91  */
  92 static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
  93 {
  94         struct dn_scp *scp = &sk->protinfo.dn;
  95         unsigned short type = ((ack >> 12) & 0x0003);
  96         int wakeup = 0;
  97
  98         switch(type) {
  99                 case 0: /* ACK - Data */
 100                         if (after(ack, scp->ackrcv_dat)) {
 101                                 scp->ackrcv_dat = ack & 0x0fff;
 102                                 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
 103                         }
 104                         break;
 105                 case 1: /* NAK - Data */
 106                         break;
 107                 case 2: /* ACK - OtherData */
 108                         if (after(ack, scp->ackrcv_oth)) {
 109                                 scp->ackrcv_oth = ack & 0x0fff;
 110                                 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
 111                         }
 112                         break;
 113                 case 3: /* NAK - OtherData */
 114                         break;
 115         }
 116
 117         if (wakeup && !sk->dead)
 118                 sk->state_change(sk);
 119 }
 120
 121 /*
 122  * This function is a universal ack processor.
 123  */
 124 static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
 125 {
 126         unsigned short *ptr = (unsigned short *)skb->data;
 127         int len = 0;
 128         unsigned short ack;
 129
 130         if (skb->len < 2)
 131                 return len;
 132
 133         if ((ack = dn_ntohs(*ptr)) & 0x8000) {
 134                 skb_pull(skb, 2);
 135                 ptr++;
 136                 len += 2;
 137                 if ((ack & 0x4000) == 0) {
 138                         if (oth)
 139                                 ack ^= 0x2000;
 140                         dn_ack(sk, skb, ack);
 141                 }
 142         }
 143
 144         if (skb->len < 2)
 145                 return len;
 146
 147         if ((ack = dn_ntohs(*ptr)) & 0x8000) {
 148                 skb_pull(skb, 2);
 149                 len += 2;
 150                 if ((ack & 0x4000) == 0) {
 151                         if (oth)
 152                                 ack ^= 0x2000;
 153                         dn_ack(sk, skb, ack);
 154                 }
 155         }
 156
 157         return len;
 158 }
 159
 160
 161 /**
 162  * dn_check_idf - Check an image data field format is correct.
 163  * @pptr: Pointer to pointer to image data
 164  * @len: Pointer to length of image data
 165  * @max: The maximum allowed length of the data in the image data field
 166  * @follow_on: Check that this many bytes exist beyond the end of the image data
 167  *
 168  * Returns: 0 if ok, -1 on error
 169  */
 170 static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
 171 {
 172         unsigned char *ptr = *pptr;
 173         unsigned char flen = *ptr++;
 174
 175         (*len)--;
 176         if (flen > max)
 177                 return -1;
 178         if ((flen + follow_on) > *len)
 179                 return -1;
 180
 181         *len -= flen;
 182         *pptr = ptr + flen;
 183         return 0;
 184 }
 185
 186 /*
 187  * Table of reason codes to pass back to node which sent us a badly
 188  * formed message, plus text messages for the log. A zero entry in
 189  * the reason field means "don't reply" otherwise a disc init is sent with
 190  * the specified reason code.
 191  */
 192 static struct {
 193         unsigned short reason;
 194         const char *text;
 195 } ci_err_table[] = {
 196  { 0,             "CI: Truncated message" },
 197  { NSP_REASON_ID, "CI: Destination username error" },
 198  { NSP_REASON_ID, "CI: Destination username type" },
 199  { NSP_REASON_US, "CI: Source username error" },
 200  { 0,             "CI: Truncated at menuver" },
 201  { 0,             "CI: Truncated before access or user data" },
 202  { NSP_REASON_IO, "CI: Access data format error" },
 203  { NSP_REASON_IO, "CI: User data format error" }
 204 };
 205
 206 /*
 207  * This function uses a slightly different lookup method
 208  * to find its sockets, since it searches on object name/number
 209  * rather than port numbers. Various tests are done to ensure that
 210  * the incoming data is in the correct format before it is queued to
 211  * a socket.
 212  */
 213 static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
 214 {
 215         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 216         struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
 217         struct sockaddr_dn dstaddr;
 218         struct sockaddr_dn srcaddr;
 219         unsigned char type = 0;
 220         int dstlen;
 221         int srclen;
 222         unsigned char *ptr;
 223         int len;
 224         int err = 0;
 225         unsigned char menuver;
 226
 227         memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
 228         memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
 229
 230         /*
 231          * 1. Decode & remove message header
 232          */
 233         cb->src_port = msg->srcaddr;
 234         cb->dst_port = msg->dstaddr;
 235         cb->services = msg->services;
 236         cb->info     = msg->info;
 237         cb->segsize  = dn_ntohs(msg->segsize);
 238
 239         if (skb->len < sizeof(*msg))
 240                 goto err_out;
 241
 242         skb_pull(skb, sizeof(*msg));
 243
 244         len = skb->len;
 245         ptr = skb->data;
 246
 247         /*
 248          * 2. Check destination end username format
 249          */
 250         dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
 251         err++;
 252         if (dstlen < 0)
 253                 goto err_out;
 254
 255         err++;
 256         if (type > 1)
 257                 goto err_out;
 258
 259         len -= dstlen;
 260         ptr += dstlen;
 261
 262         /*
 263          * 3. Check source end username format
 264          */
 265         srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
 266         err++;
 267         if (srclen < 0)
 268                 goto err_out;
 269
 270         len -= srclen;
 271         ptr += srclen;
 272         err++;
 273         if (len < 1)
 274                 goto err_out;
 275
 276         menuver = *ptr;
 277         ptr++;
 278         len--;
 279
 280         /*
 281          * 4. Check that optional data actually exists if menuver says it does
 282          */
 283         err++;
 284         if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
 285                 goto err_out;
 286
 287         /*
 288          * 5. Check optional access data format
 289          */
 290         err++;
 291         if (menuver & DN_MENUVER_ACC) {
 292                 if (dn_check_idf(&ptr, &len, 39, 1))
 293                         goto err_out;
 294                 if (dn_check_idf(&ptr, &len, 39, 1))
 295                         goto err_out;
 296                 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
 297                         goto err_out;
 298         }
 299
 300         /*
 301          * 6. Check optional user data format
 302          */
 303         err++;
 304         if (menuver & DN_MENUVER_USR) {
 305                 if (dn_check_idf(&ptr, &len, 16, 0))
 306                         goto err_out;
 307         }
 308
 309         /*
 310          * 7. Look up socket based on destination end username
 311          */
 312         return dn_sklist_find_listener(&dstaddr);
 313 err_out:
 314         dn_log_martian(skb, ci_err_table[err].text);
 315         *reason = ci_err_table[err].reason;
 316         return NULL;
 317 }
 318
 319
 320 static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
 321 {
 322         if (sk->ack_backlog >= sk->max_ack_backlog) {
 323                 kfree_skb(skb);
 324                 return;
 325         }
 326
 327         sk->ack_backlog++;
 328         skb_queue_tail(&sk->receive_queue, skb);
 329         sk->state_change(sk);
 330 }
 331
 332 static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
 333 {
 334         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 335         struct dn_scp *scp = &sk->protinfo.dn;
 336
 337         if (skb->len < 3)
 338                 goto out;
 339
 340         cb->services = *skb->data;
 341         cb->info = *(skb->data+1);
 342         skb_pull(skb, 2);
 343         cb->segsize = dn_ntohs(*(__u16 *)skb->data);
 344         skb_pull(skb, 2);
 345
 346         /*
 347          * FIXME: Check out services and info fields to check that
 348          * we can talk to this kind of node.
 349          */
 350
 351         if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
 352                 scp->persist = 0;
 353                 scp->addrrem = cb->src_port;
 354                 sk->state = TCP_ESTABLISHED;
 355                 scp->state = DN_RUN;
 356
 357                 if (scp->mss > cb->segsize)
 358                         scp->mss = cb->segsize;
 359                 if (scp->mss < 230)
 360                         scp->mss = 230;
 361
 362                 if (skb->len > 0) {
 363                         unsigned char dlen = *skb->data;
 364                         if ((dlen <= 16) && (dlen <= skb->len)) {
 365                                 scp->conndata_in.opt_optl = dlen;
 366                                 memcpy(scp->conndata_in.opt_data, skb->data + 1, dlen);
 367                         }
 368                 }
 369                 dn_nsp_send_lnk(sk, DN_NOCHANGE);
 370                 if (!sk->dead)
 371                         sk->state_change(sk);
 372         }
 373
 374 out:
 375         kfree_skb(skb);
 376 }
 377
 378 static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
 379 {
 380         struct dn_scp *scp = &sk->protinfo.dn;
 381
 382         if (scp->state == DN_CI) {
 383                 scp->state = DN_CD;
 384                 scp->persist = 0;
 385         }
 386
 387         kfree_skb(skb);
 388 }
 389
 390 static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
 391 {
 392         struct dn_scp *scp = &sk->protinfo.dn;
 393         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 394         unsigned short reason;
 395
 396         if (skb->len < 2)
 397                 goto out;
 398
 399         reason = dn_ntohs(*(__u16 *)skb->data);
 400         skb_pull(skb, 2);
 401
 402         scp->discdata_in.opt_status = reason;
 403         scp->discdata_in.opt_optl   = 0;
 404         memset(scp->discdata_in.opt_data, 0, 16);
 405
 406         if (skb->len > 0) {
 407                 unsigned char dlen = *skb->data;
 408                 if ((dlen <= 16) && (dlen <= skb->len)) {
 409                         scp->discdata_in.opt_optl = dlen;
 410                         memcpy(scp->discdata_in.opt_data, skb->data + 1, dlen);
 411                 }
 412         }
 413
 414         scp->addrrem = cb->src_port;
 415         sk->state    = TCP_CLOSE;
 416
 417         switch(scp->state) {
 418                 case DN_CI:
 419                 case DN_CD:
 420                         scp->state = DN_RJ;
 421                         break;
 422                 case DN_RUN:
 423                         sk->shutdown |= SHUTDOWN_MASK;
 424                         scp->state = DN_DN;
 425                         break;
 426                 case DN_DI:
 427                         scp->state = DN_DIC;
 428                         break;
 429         }
 430
 431         if (!sk->dead) {
 432                 if (sk->socket->state != SS_UNCONNECTED)
 433                         sk->socket->state = SS_DISCONNECTING;
 434                 sk->state_change(sk);
 435         }
 436
 437         dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
 438         scp->persist_fxn = dn_destroy_timer;
 439         scp->persist = dn_nsp_persist(sk);
 440
 441 out:
 442         kfree_skb(skb);
 443 }
 444
 445 /*
 446  * disc_conf messages are also called no_resources or no_link
 447  * messages depending upon the "reason" field.
 448  */
 449 static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
 450 {
 451         struct dn_scp *scp = &sk->protinfo.dn;
 452         unsigned short reason;
 453
 454         if (skb->len != 2)
 455                 goto out;
 456
 457         reason = dn_ntohs(*(__u16 *)skb->data);
 458
 459         sk->state = TCP_CLOSE;
 460
 461         switch(scp->state) {
 462                 case DN_CI:
 463                         scp->state = DN_NR;
 464                         break;
 465                 case DN_DR:
 466                         if (reason == NSP_REASON_DC)
 467                                 scp->state = DN_DRC;
 468                         if (reason == NSP_REASON_NL)
 469                                 scp->state = DN_CN;
 470                         break;
 471                 case DN_DI:
 472                         scp->state = DN_DIC;
 473                         break;
 474                 case DN_RUN:
 475                         sk->shutdown |= SHUTDOWN_MASK;
 476                 case DN_CC:
 477                         scp->state = DN_CN;
 478         }
 479
 480         if (!sk->dead) {
 481                 if (sk->socket->state != SS_UNCONNECTED)
 482                         sk->socket->state = SS_DISCONNECTING;
 483                 sk->state_change(sk);
 484         }
 485
 486         scp->persist_fxn = dn_destroy_timer;
 487         scp->persist = dn_nsp_persist(sk);
 488
 489 out:
 490         kfree_skb(skb);
 491 }
 492
 493 static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
 494 {
 495         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 496         unsigned short segnum;
 497         unsigned char lsflags;
 498         char fcval;
 499
 500         if (skb->len != 4)
 501                 goto out;
 502
 503         cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
 504         skb_pull(skb, 2);
 505         lsflags = *(unsigned char *)skb->data;
 506         skb_pull(skb, 1);
 507         fcval = *(char *)skb->data;
 508
 509         if (lsflags & 0xf0)
 510                 goto out;
 511
 512         if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0FFF) == (segnum & 0x0FFF)) {
 513                 sk->protinfo.dn.numoth_rcv += 1;
 514                 switch(lsflags & 0x03) {
 515                         case 0x00:
 516                                 break;
 517                         case 0x01:
 518                                 sk->protinfo.dn.flowrem_sw = DN_DONTSEND;
 519                                 break;
 520                         case 0x02:
 521                                 sk->protinfo.dn.flowrem_sw = DN_SEND;
 522                                 dn_nsp_output(sk);
 523                                 if (!sk->dead)
 524                                         sk->state_change(sk);
 525                 }
 526
 527         }
 528
 529         dn_nsp_send_oth_ack(sk);
 530
 531 out:
 532         kfree_skb(skb);
 533 }
 534
 535 /*
 536  * Copy of sock_queue_rcv_skb (from sock.h) without
 537  * bh_lock_sock() (its already held when this is called) which
 538  * also allows data and other data to be queued to a socket.
 539  */
 540 static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
 541 {
 542 #ifdef CONFIG_FILTER
 543         struct sk_filter *filter;
 544 #endif
 545
 546         /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
 547            number of warnings when compiling with -W --ANK
 548          */
 549         if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf
 550 )
 551                 return -ENOMEM;
 552
 553 #ifdef CONFIG_FILTER
 554         if (sk->filter) {
 555                 int err = 0;
 556                 if ((filter = sk->filter) != NULL && sk_filter(skb, sk->filter))
 557                         err = -EPERM;  /* Toss packet */
 558                 if (err)
 559                         return err;
 560         }
 561 #endif /* CONFIG_FILTER */
 562
 563         skb_set_owner_r(skb, sk);
 564         skb_queue_tail(queue, skb);
 565
 566         /* This code only runs from BH or BH protected context.
 567          * Therefore the plain read_lock is ok here. -DaveM
 568          */
 569         read_lock(&sk->callback_lock);
 570         if (!sk->dead) {
 571                 struct socket *sock = sk->socket;
 572                 wake_up_interruptible(sk->sleep);
 573                 if (sock && sock->fasync_list &&
 574                     !test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
 575                         __kill_fasync(sock->fasync_list, sig,
 576                                     (sig == SIGURG) ? POLL_PRI : POLL_IN);
 577         }
 578         read_unlock(&sk->callback_lock);
 579
 580         return 0;
 581 }
 582
 583 static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
 584 {
 585         struct dn_scp *scp = &sk->protinfo.dn;
 586         unsigned short segnum;
 587         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 588         int queued = 0;
 589
 590         if (skb->len < 2)
 591                 goto out;
 592
 593         cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
 594         skb_pull(skb, 2);
 595
 596         if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0fff) == (segnum & 0x0fff)) {
 597
 598                 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
 599                         sk->protinfo.dn.numoth_rcv++;
 600                         scp->other_report = 0;
 601                         queued = 1;
 602                 }
 603         }
 604
 605         dn_nsp_send_oth_ack(sk);
 606 out:
 607         if (!queued)
 608                 kfree_skb(skb);
 609 }
 610
 611 static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
 612 {
 613         int queued = 0;
 614         unsigned short segnum;
 615         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 616         struct dn_scp *scp = &sk->protinfo.dn;
 617
 618         if (skb->len < 2)
 619                 goto out;
 620
 621         cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
 622         skb_pull(skb, 2);
 623
 624         if (((sk->protinfo.dn.numdat_rcv + 1) & 0x0FFF) ==
 625                      (segnum & 0x0FFF)) {
 626
 627                 if (dn_queue_skb(sk, skb, SIGIO, &sk->receive_queue) == 0) {
 628                         sk->protinfo.dn.numdat_rcv++;
 629                         queued = 1;
 630                 }
 631
 632                 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
 633                         scp->flowloc_sw = DN_DONTSEND;
 634                         dn_nsp_send_lnk(sk, DN_DONTSEND);
 635                 }
 636         }
 637
 638         dn_nsp_send_data_ack(sk);
 639 out:
 640         if (!queued)
 641                 kfree_skb(skb);
 642 }
 643
 644 /*
 645  * If one of our conninit messages is returned, this function
 646  * deals with it. It puts the socket into the NO_COMMUNICATION
 647  * state.
 648  */
 649 static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
 650 {
 651         struct dn_scp *scp = &sk->protinfo.dn;
 652
 653         if (scp->state == DN_CI) {
 654                 scp->state = DN_NC;
 655                 sk->state = TCP_CLOSE;
 656                 if (!sk->dead)
 657                         sk->state_change(sk);
 658         }
 659
 660         kfree_skb(skb);
 661 }
 662
 663 static void dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
 664 {
 665         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 666
 667         if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
 668                 switch(cb->nsp_flags & 0x70) {
 669                         case 0x10:
 670                         case 0x60: /* (Retransmitted) Connect Init */
 671                                 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
 672                                 break;
 673                         case 0x20: /* Connect Confirm */
 674                                 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
 675                                 break;
 676                 }
 677         }
 678
 679         kfree_skb(skb);
 680 }
 681
 682 static int dn_nsp_rx_packet(struct sk_buff *skb)
 683 {
 684         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 685         struct sock *sk = NULL;
 686         unsigned char *ptr = (unsigned char *)skb->data;
 687         unsigned short reason = NSP_REASON_NL;
 688
 689         skb->h.raw    = skb->data;
 690         cb->nsp_flags = *ptr++;
 691
 692         if (decnet_debug_level & 2)
 693                 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
 694
 695         if (skb->len < 2)
 696                 goto free_out;
 697
 698         if (cb->nsp_flags & 0x83)
 699                 goto free_out;
 700
 701         /*
 702          * Returned packets...
 703          * Swap src & dst and look up in the normal way.
 704          */
 705         if (cb->rt_flags & DN_RT_F_RTS) {
 706                 unsigned short tmp = cb->dst_port;
 707                 cb->dst_port = cb->src_port;
 708                 cb->src_port = tmp;
 709                 tmp = cb->dst;
 710                 cb->dst = cb->src;
 711                 cb->src = tmp;
 712                 sk = dn_find_by_skb(skb);
 713                 goto got_it;
 714         }
 715
 716         /*
 717          * Filter out conninits and useless packet types
 718          */
 719         if ((cb->nsp_flags & 0x0c) == 0x08) {
 720                 switch(cb->nsp_flags & 0x70) {
 721                         case 0x00: /* NOP */
 722                         case 0x70: /* Reserved */
 723                         case 0x50: /* Reserved, Phase II node init */
 724                                 goto free_out;
 725                         case 0x10:
 726                         case 0x60:
 727                                 sk = dn_find_listener(skb, &reason);
 728                                 goto got_it;
 729                 }
 730         }
 731
 732         if (skb->len < 3)
 733                 goto free_out;
 734
 735         /*
 736          * Grab the destination address.
 737          */
 738         cb->dst_port = *(unsigned short *)ptr;
 739         cb->src_port = 0;
 740         ptr += 2;
 741
 742         /*
 743          * If not a connack, grab the source address too.
 744          */
 745         if (skb->len >= 5) {
 746                 cb->src_port = *(unsigned short *)ptr;
 747                 ptr += 2;
 748                 skb_pull(skb, 5);
 749         }
 750
 751         /*
 752          * Find the socket to which this skb is destined.
 753          */
 754         sk = dn_find_by_skb(skb);
 755 got_it:
 756         if (sk != NULL) {
 757                 struct dn_scp *scp = &sk->protinfo.dn;
 758                 int ret;
 759
 760                 /* Reset backoff */
 761                 scp->nsp_rxtshift = 0;
 762
 763                 bh_lock_sock(sk);
 764                 ret = 0;
 765                 if (sk->lock.users == 0)
 766                         ret = dn_nsp_backlog_rcv(sk, skb);
 767                 else
 768                         sk_add_backlog(sk, skb);
 769                 bh_unlock_sock(sk);
 770                 sock_put(sk);
 771
 772                 return ret;
 773         }
 774
 775         dn_nsp_no_socket(skb, reason);
 776         return 1;
 777
 778 free_out:
 779         kfree_skb(skb);
 780         return 0;
 781 }
 782
 783 int dn_nsp_rx(struct sk_buff *skb)
 784 {
 785         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
 786 }
 787
 788 /*
 789  * This is the main receive routine for sockets. It is called
 790  * from the above when the socket is not busy, and also from
 791  * sock_release() when there is a backlog queued up.
 792  */
 793 int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 794 {
 795         struct dn_scp *scp = &sk->protinfo.dn;
 796         struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
 797
 798         if (cb->rt_flags & DN_RT_F_RTS) {
 799                 dn_returned_conn_init(sk, skb);
 800                 return 0;
 801         }
 802
 803         /*
 804          * Control packet.
 805          */
 806         if ((cb->nsp_flags & 0x0c) == 0x08) {
 807                 switch(cb->nsp_flags & 0x70) {
 808                         case 0x10:
 809                         case 0x60:
 810                                 dn_nsp_conn_init(sk, skb);
 811                                 break;
 812                         case 0x20:
 813                                 dn_nsp_conn_conf(sk, skb);
 814                                 break;
 815                         case 0x30:
 816                                 dn_nsp_disc_init(sk, skb);
 817                                 break;
 818                         case 0x40:
 819                                 dn_nsp_disc_conf(sk, skb);
 820                                 break;
 821                 }
 822
 823         } else if (cb->nsp_flags == 0x24) {
 824                 /*
 825                  * Special for connacks, 'cos they don't have
 826                  * ack data or ack otherdata info.
 827                  */
 828                 dn_nsp_conn_ack(sk, skb);
 829         } else {
 830                 int other = 1;
 831
 832                 /* both data and ack frames can kick a CC socket into RUN */
 833                 if ((scp->state == DN_CC) && !sk->dead) {
 834                         scp->state = DN_RUN;
 835                         sk->state = TCP_ESTABLISHED;
 836                         sk->state_change(sk);
 837                 }
 838
 839                 if ((cb->nsp_flags & 0x1c) == 0)
 840                         other = 0;
 841                 if (cb->nsp_flags == 0x04)
 842                         other = 0;
 843
 844                 /*
 845                  * Read out ack data here, this applies equally
 846                  * to data, other data, link serivce and both
 847                  * ack data and ack otherdata.
 848                  */
 849                 dn_process_ack(sk, skb, other);
 850
 851                 /*
 852                  * If we've some sort of data here then call a
 853                  * suitable routine for dealing with it, otherwise
 854                  * the packet is an ack and can be discarded.
 855                  */
 856                 if ((cb->nsp_flags & 0x0c) == 0) {
 857
 858                         if (scp->state != DN_RUN)
 859                                 goto free_out;
 860
 861                         switch(cb->nsp_flags) {
 862                                 case 0x10: /* LS */
 863                                         dn_nsp_linkservice(sk, skb);
 864                                         break;
 865                                 case 0x30: /* OD */
 866                                         dn_nsp_otherdata(sk, skb);
 867                                         break;
 868                                 default:
 869                                         dn_nsp_data(sk, skb);
 870                         }
 871
 872                 } else { /* Ack, chuck it out here */
 873 free_out:
 874                         kfree_skb(skb);
 875                 }
 876         }
 877
 878         return 0;
 879 }
 880