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  *    Steve Whitehouse:  Added backlog congestion level return codes.
  29  *   Patrick Caulfield:
  30  *    Steve Whitehouse:  Added flow control support (outbound)
  31  *    Steve Whitehouse:  Prepare for nonlinear skbs
  32  */
  33
  34 /******************************************************************************
  35     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  36
  37     This program is free software; you can redistribute it and/or modify
  38     it under the terms of the GNU General Public License as published by
  39     the Free Software Foundation; either version 2 of the License, or
  40     any later version.
  41
  42     This program is distributed in the hope that it will be useful,
  43     but WITHOUT ANY WARRANTY; without even the implied warranty of
  44     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  45     GNU General Public License for more details.
  46 *******************************************************************************/
  47
  48 #include <linux/errno.h>
  49 #include <linux/types.h>
  50 #include <linux/socket.h>
  51 #include <linux/in.h>
  52 #include <linux/kernel.h>
  53 #include <linux/timer.h>
  54 #include <linux/string.h>
  55 #include <linux/sockios.h>
  56 #include <linux/net.h>
  57 #include <linux/netdevice.h>
  58 #include <linux/inet.h>
  59 #include <linux/route.h>
  60 #include <net/sock.h>
  61 #include <net/tcp_states.h>
  62 #include <asm/system.h>
  63 #include <linux/fcntl.h>
  64 #include <linux/mm.h>
  65 #include <linux/termios.h>
  66 #include <linux/interrupt.h>
  67 #include <linux/proc_fs.h>
  68 #include <linux/stat.h>
  69 #include <linux/init.h>
  70 #include <linux/poll.h>
  71 #include <linux/netfilter_decnet.h>
  72 #include <net/neighbour.h>
  73 #include <net/dst.h>
  74 #include <net/dn.h>
  75 #include <net/dn_nsp.h>
  76 #include <net/dn_dev.h>
  77 #include <net/dn_route.h>
  78
  79 extern int decnet_log_martians;
  80
  81 static void dn_log_martian(struct sk_buff *skb, const char *msg)
  82 {
  83         if (decnet_log_martians && net_ratelimit()) {
  84                 char *devname = skb->dev ? skb->dev->name : "???";
  85                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
  86                 printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n", msg, devname, dn_ntohs(cb->src), dn_ntohs(cb->dst), dn_ntohs(cb->src_port), dn_ntohs(cb->dst_port));
  87         }
  88 }
  89
  90 /*
  91  * For this function we've flipped the cross-subchannel bit
  92  * if the message is an otherdata or linkservice message. Thus
  93  * we can use it to work out what to update.
  94  */
  95 static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
  96 {
  97         struct dn_scp *scp = DN_SK(sk);
  98         unsigned short type = ((ack >> 12) & 0x0003);
  99         int wakeup = 0;
 100
 101         switch(type) {
 102                 case 0: /* ACK - Data */
 103                         if (dn_after(ack, scp->ackrcv_dat)) {
 104                                 scp->ackrcv_dat = ack & 0x0fff;
 105                                 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
 106                         }
 107                         break;
 108                 case 1: /* NAK - Data */
 109                         break;
 110                 case 2: /* ACK - OtherData */
 111                         if (dn_after(ack, scp->ackrcv_oth)) {
 112                                 scp->ackrcv_oth = ack & 0x0fff;
 113                                 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
 114                         }
 115                         break;
 116                 case 3: /* NAK - OtherData */
 117                         break;
 118         }
 119
 120         if (wakeup && !sock_flag(sk, SOCK_DEAD))
 121                 sk->sk_state_change(sk);
 122 }
 123
 124 /*
 125  * This function is a universal ack processor.
 126  */
 127 static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
 128 {
 129         __le16 *ptr = (__le16 *)skb->data;
 130         int len = 0;
 131         unsigned short ack;
 132
 133         if (skb->len < 2)
 134                 return len;
 135
 136         if ((ack = dn_ntohs(*ptr)) & 0x8000) {
 137                 skb_pull(skb, 2);
 138                 ptr++;
 139                 len += 2;
 140                 if ((ack & 0x4000) == 0) {
 141                         if (oth)
 142                                 ack ^= 0x2000;
 143                         dn_ack(sk, skb, ack);
 144                 }
 145         }
 146
 147         if (skb->len < 2)
 148                 return len;
 149
 150         if ((ack = dn_ntohs(*ptr)) & 0x8000) {
 151                 skb_pull(skb, 2);
 152                 len += 2;
 153                 if ((ack & 0x4000) == 0) {
 154                         if (oth)
 155                                 ack ^= 0x2000;
 156                         dn_ack(sk, skb, ack);
 157                 }
 158         }
 159
 160         return len;
 161 }
 162
 163
 164 /**
 165  * dn_check_idf - Check an image data field format is correct.
 166  * @pptr: Pointer to pointer to image data
 167  * @len: Pointer to length of image data
 168  * @max: The maximum allowed length of the data in the image data field
 169  * @follow_on: Check that this many bytes exist beyond the end of the image data
 170  *
 171  * Returns: 0 if ok, -1 on error
 172  */
 173 static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
 174 {
 175         unsigned char *ptr = *pptr;
 176         unsigned char flen = *ptr++;
 177
 178         (*len)--;
 179         if (flen > max)
 180                 return -1;
 181         if ((flen + follow_on) > *len)
 182                 return -1;
 183
 184         *len -= flen;
 185         *pptr = ptr + flen;
 186         return 0;
 187 }
 188
 189 /*
 190  * Table of reason codes to pass back to node which sent us a badly
 191  * formed message, plus text messages for the log. A zero entry in
 192  * the reason field means "don't reply" otherwise a disc init is sent with
 193  * the specified reason code.
 194  */
 195 static struct {
 196         unsigned short reason;
 197         const char *text;
 198 } ci_err_table[] = {
 199  { 0,             "CI: Truncated message" },
 200  { NSP_REASON_ID, "CI: Destination username error" },
 201  { NSP_REASON_ID, "CI: Destination username type" },
 202  { NSP_REASON_US, "CI: Source username error" },
 203  { 0,             "CI: Truncated at menuver" },
 204  { 0,             "CI: Truncated before access or user data" },
 205  { NSP_REASON_IO, "CI: Access data format error" },
 206  { NSP_REASON_IO, "CI: User data format error" }
 207 };
 208
 209 /*
 210  * This function uses a slightly different lookup method
 211  * to find its sockets, since it searches on object name/number
 212  * rather than port numbers. Various tests are done to ensure that
 213  * the incoming data is in the correct format before it is queued to
 214  * a socket.
 215  */
 216 static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
 217 {
 218         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 219         struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
 220         struct sockaddr_dn dstaddr;
 221         struct sockaddr_dn srcaddr;
 222         unsigned char type = 0;
 223         int dstlen;
 224         int srclen;
 225         unsigned char *ptr;
 226         int len;
 227         int err = 0;
 228         unsigned char menuver;
 229
 230         memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
 231         memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
 232
 233         /*
 234          * 1. Decode & remove message header
 235          */
 236         cb->src_port = msg->srcaddr;
 237         cb->dst_port = msg->dstaddr;
 238         cb->services = msg->services;
 239         cb->info     = msg->info;
 240         cb->segsize  = dn_ntohs(msg->segsize);
 241
 242         if (!pskb_may_pull(skb, sizeof(*msg)))
 243                 goto err_out;
 244
 245         skb_pull(skb, sizeof(*msg));
 246
 247         len = skb->len;
 248         ptr = skb->data;
 249
 250         /*
 251          * 2. Check destination end username format
 252          */
 253         dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
 254         err++;
 255         if (dstlen < 0)
 256                 goto err_out;
 257
 258         err++;
 259         if (type > 1)
 260                 goto err_out;
 261
 262         len -= dstlen;
 263         ptr += dstlen;
 264
 265         /*
 266          * 3. Check source end username format
 267          */
 268         srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
 269         err++;
 270         if (srclen < 0)
 271                 goto err_out;
 272
 273         len -= srclen;
 274         ptr += srclen;
 275         err++;
 276         if (len < 1)
 277                 goto err_out;
 278
 279         menuver = *ptr;
 280         ptr++;
 281         len--;
 282
 283         /*
 284          * 4. Check that optional data actually exists if menuver says it does
 285          */
 286         err++;
 287         if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
 288                 goto err_out;
 289
 290         /*
 291          * 5. Check optional access data format
 292          */
 293         err++;
 294         if (menuver & DN_MENUVER_ACC) {
 295                 if (dn_check_idf(&ptr, &len, 39, 1))
 296                         goto err_out;
 297                 if (dn_check_idf(&ptr, &len, 39, 1))
 298                         goto err_out;
 299                 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
 300                         goto err_out;
 301         }
 302
 303         /*
 304          * 6. Check optional user data format
 305          */
 306         err++;
 307         if (menuver & DN_MENUVER_USR) {
 308                 if (dn_check_idf(&ptr, &len, 16, 0))
 309                         goto err_out;
 310         }
 311
 312         /*
 313          * 7. Look up socket based on destination end username
 314          */
 315         return dn_sklist_find_listener(&dstaddr);
 316 err_out:
 317         dn_log_martian(skb, ci_err_table[err].text);
 318         *reason = ci_err_table[err].reason;
 319         return NULL;
 320 }
 321
 322
 323 static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
 324 {
 325         if (sk_acceptq_is_full(sk)) {
 326                 kfree_skb(skb);
 327                 return;
 328         }
 329
 330         sk->sk_ack_backlog++;
 331         skb_queue_tail(&sk->sk_receive_queue, skb);
 332         sk->sk_state_change(sk);
 333 }
 334
 335 static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
 336 {
 337         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 338         struct dn_scp *scp = DN_SK(sk);
 339         unsigned char *ptr;
 340
 341         if (skb->len < 4)
 342                 goto out;
 343
 344         ptr = skb->data;
 345         cb->services = *ptr++;
 346         cb->info = *ptr++;
 347         cb->segsize = dn_ntohs(*(__le16 *)ptr);
 348
 349         if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
 350                 scp->persist = 0;
 351                 scp->addrrem = cb->src_port;
 352                 sk->sk_state = TCP_ESTABLISHED;
 353                 scp->state = DN_RUN;
 354                 scp->services_rem = cb->services;
 355                 scp->info_rem = cb->info;
 356                 scp->segsize_rem = cb->segsize;
 357
 358                 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
 359                         scp->max_window = decnet_no_fc_max_cwnd;
 360
 361                 if (skb->len > 0) {
 362                         u16 dlen = *skb->data;
 363                         if ((dlen <= 16) && (dlen <= skb->len)) {
 364                                 scp->conndata_in.opt_optl = dn_htons(dlen);
 365                                 memcpy(scp->conndata_in.opt_data, skb->data + 1, dlen);
 366                         }
 367                 }
 368                 dn_nsp_send_link(sk, DN_NOCHANGE, 0);
 369                 if (!sock_flag(sk, SOCK_DEAD))
 370                         sk->sk_state_change(sk);
 371         }
 372
 373 out:
 374         kfree_skb(skb);
 375 }
 376
 377 static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
 378 {
 379         struct dn_scp *scp = DN_SK(sk);
 380
 381         if (scp->state == DN_CI) {
 382                 scp->state = DN_CD;
 383                 scp->persist = 0;
 384         }
 385
 386         kfree_skb(skb);
 387 }
 388
 389 static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
 390 {
 391         struct dn_scp *scp = DN_SK(sk);
 392         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 393         unsigned short reason;
 394
 395         if (skb->len < 2)
 396                 goto out;
 397
 398         reason = dn_ntohs(*(__le16 *)skb->data);
 399         skb_pull(skb, 2);
 400
 401         scp->discdata_in.opt_status = dn_htons(reason);
 402         scp->discdata_in.opt_optl   = 0;
 403         memset(scp->discdata_in.opt_data, 0, 16);
 404
 405         if (skb->len > 0) {
 406                 u16 dlen = *skb->data;
 407                 if ((dlen <= 16) && (dlen <= skb->len)) {
 408                         scp->discdata_in.opt_optl = dn_htons(dlen);
 409                         memcpy(scp->discdata_in.opt_data, skb->data + 1, dlen);
 410                 }
 411         }
 412
 413         scp->addrrem = cb->src_port;
 414         sk->sk_state = TCP_CLOSE;
 415
 416         switch(scp->state) {
 417                 case DN_CI:
 418                 case DN_CD:
 419                         scp->state = DN_RJ;
 420                         sk->sk_err = ECONNREFUSED;
 421                         break;
 422                 case DN_RUN:
 423                         sk->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 (!sock_flag(sk, SOCK_DEAD)) {
 432                 if (sk->sk_socket->state != SS_UNCONNECTED)
 433                         sk->sk_socket->state = SS_DISCONNECTING;
 434                 sk->sk_state_change(sk);
 435         }
 436
 437         /*
 438          * It appears that its possible for remote machines to send disc
 439          * init messages with no port identifier if we are in the CI and
 440          * possibly also the CD state. Obviously we shouldn't reply with
 441          * a message if we don't know what the end point is.
 442          */
 443         if (scp->addrrem) {
 444                 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
 445         }
 446         scp->persist_fxn = dn_destroy_timer;
 447         scp->persist = dn_nsp_persist(sk);
 448
 449 out:
 450         kfree_skb(skb);
 451 }
 452
 453 /*
 454  * disc_conf messages are also called no_resources or no_link
 455  * messages depending upon the "reason" field.
 456  */
 457 static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
 458 {
 459         struct dn_scp *scp = DN_SK(sk);
 460         unsigned short reason;
 461
 462         if (skb->len != 2)
 463                 goto out;
 464
 465         reason = dn_ntohs(*(__le16 *)skb->data);
 466
 467         sk->sk_state = TCP_CLOSE;
 468
 469         switch(scp->state) {
 470                 case DN_CI:
 471                         scp->state = DN_NR;
 472                         break;
 473                 case DN_DR:
 474                         if (reason == NSP_REASON_DC)
 475                                 scp->state = DN_DRC;
 476                         if (reason == NSP_REASON_NL)
 477                                 scp->state = DN_CN;
 478                         break;
 479                 case DN_DI:
 480                         scp->state = DN_DIC;
 481                         break;
 482                 case DN_RUN:
 483                         sk->sk_shutdown |= SHUTDOWN_MASK;
 484                 case DN_CC:
 485                         scp->state = DN_CN;
 486         }
 487
 488         if (!sock_flag(sk, SOCK_DEAD)) {
 489                 if (sk->sk_socket->state != SS_UNCONNECTED)
 490                         sk->sk_socket->state = SS_DISCONNECTING;
 491                 sk->sk_state_change(sk);
 492         }
 493
 494         scp->persist_fxn = dn_destroy_timer;
 495         scp->persist = dn_nsp_persist(sk);
 496
 497 out:
 498         kfree_skb(skb);
 499 }
 500
 501 static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
 502 {
 503         struct dn_scp *scp = DN_SK(sk);
 504         unsigned short segnum;
 505         unsigned char lsflags;
 506         signed char fcval;
 507         int wake_up = 0;
 508         char *ptr = skb->data;
 509         unsigned char fctype = scp->services_rem & NSP_FC_MASK;
 510
 511         if (skb->len != 4)
 512                 goto out;
 513
 514         segnum = dn_ntohs(*(__le16 *)ptr);
 515         ptr += 2;
 516         lsflags = *(unsigned char *)ptr++;
 517         fcval = *ptr;
 518
 519         /*
 520          * Here we ignore erronous packets which should really
 521          * should cause a connection abort. It is not critical
 522          * for now though.
 523          */
 524         if (lsflags & 0xf8)
 525                 goto out;
 526
 527         if (seq_next(scp->numoth_rcv, segnum)) {
 528                 seq_add(&scp->numoth_rcv, 1);
 529                 switch(lsflags & 0x04) { /* FCVAL INT */
 530                 case 0x00: /* Normal Request */
 531                         switch(lsflags & 0x03) { /* FCVAL MOD */
 532                         case 0x00: /* Request count */
 533                                 if (fcval < 0) {
 534                                         unsigned char p_fcval = -fcval;
 535                                         if ((scp->flowrem_dat > p_fcval) &&
 536                                             (fctype == NSP_FC_SCMC)) {
 537                                                 scp->flowrem_dat -= p_fcval;
 538                                         }
 539                                 } else if (fcval > 0) {
 540                                         scp->flowrem_dat += fcval;
 541                                         wake_up = 1;
 542                                 }
 543                                 break;
 544                         case 0x01: /* Stop outgoing data */
 545                                 scp->flowrem_sw = DN_DONTSEND;
 546                                 break;
 547                         case 0x02: /* Ok to start again */
 548                                 scp->flowrem_sw = DN_SEND;
 549                                 dn_nsp_output(sk);
 550                                 wake_up = 1;
 551                         }
 552                         break;
 553                 case 0x04: /* Interrupt Request */
 554                         if (fcval > 0) {
 555                                 scp->flowrem_oth += fcval;
 556                                 wake_up = 1;
 557                         }
 558                         break;
 559                 }
 560                 if (wake_up && !sock_flag(sk, SOCK_DEAD))
 561                         sk->sk_state_change(sk);
 562         }
 563
 564         dn_nsp_send_oth_ack(sk);
 565
 566 out:
 567         kfree_skb(skb);
 568 }
 569
 570 /*
 571  * Copy of sock_queue_rcv_skb (from sock.h) without
 572  * bh_lock_sock() (its already held when this is called) which
 573  * also allows data and other data to be queued to a socket.
 574  */
 575 static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
 576 {
 577         int err;
 578
 579         /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
 580            number of warnings when compiling with -W --ANK
 581          */
 582         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 583             (unsigned)sk->sk_rcvbuf) {
 584                 err = -ENOMEM;
 585                 goto out;
 586         }
 587
 588         err = sk_filter(sk, skb);
 589         if (err)
 590                 goto out;
 591
 592         skb_set_owner_r(skb, sk);
 593         skb_queue_tail(queue, skb);
 594
 595         /* This code only runs from BH or BH protected context.
 596          * Therefore the plain read_lock is ok here. -DaveM
 597          */
 598         read_lock(&sk->sk_callback_lock);
 599         if (!sock_flag(sk, SOCK_DEAD)) {
 600                 struct socket *sock = sk->sk_socket;
 601                 wake_up_interruptible(sk->sk_sleep);
 602                 if (sock && sock->fasync_list &&
 603                     !test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
 604                         __kill_fasync(sock->fasync_list, sig,
 605                                     (sig == SIGURG) ? POLL_PRI : POLL_IN);
 606         }
 607         read_unlock(&sk->sk_callback_lock);
 608 out:
 609         return err;
 610 }
 611
 612 static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
 613 {
 614         struct dn_scp *scp = DN_SK(sk);
 615         unsigned short segnum;
 616         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 617         int queued = 0;
 618
 619         if (skb->len < 2)
 620                 goto out;
 621
 622         cb->segnum = segnum = dn_ntohs(*(__le16 *)skb->data);
 623         skb_pull(skb, 2);
 624
 625         if (seq_next(scp->numoth_rcv, segnum)) {
 626
 627                 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
 628                         seq_add(&scp->numoth_rcv, 1);
 629                         scp->other_report = 0;
 630                         queued = 1;
 631                 }
 632         }
 633
 634         dn_nsp_send_oth_ack(sk);
 635 out:
 636         if (!queued)
 637                 kfree_skb(skb);
 638 }
 639
 640 static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
 641 {
 642         int queued = 0;
 643         unsigned short segnum;
 644         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 645         struct dn_scp *scp = DN_SK(sk);
 646
 647         if (skb->len < 2)
 648                 goto out;
 649
 650         cb->segnum = segnum = dn_ntohs(*(__le16 *)skb->data);
 651         skb_pull(skb, 2);
 652
 653         if (seq_next(scp->numdat_rcv, segnum)) {
 654                 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
 655                         seq_add(&scp->numdat_rcv, 1);
 656                         queued = 1;
 657                 }
 658
 659                 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
 660                         scp->flowloc_sw = DN_DONTSEND;
 661                         dn_nsp_send_link(sk, DN_DONTSEND, 0);
 662                 }
 663         }
 664
 665         dn_nsp_send_data_ack(sk);
 666 out:
 667         if (!queued)
 668                 kfree_skb(skb);
 669 }
 670
 671 /*
 672  * If one of our conninit messages is returned, this function
 673  * deals with it. It puts the socket into the NO_COMMUNICATION
 674  * state.
 675  */
 676 static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
 677 {
 678         struct dn_scp *scp = DN_SK(sk);
 679
 680         if (scp->state == DN_CI) {
 681                 scp->state = DN_NC;
 682                 sk->sk_state = TCP_CLOSE;
 683                 if (!sock_flag(sk, SOCK_DEAD))
 684                         sk->sk_state_change(sk);
 685         }
 686
 687         kfree_skb(skb);
 688 }
 689
 690 static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
 691 {
 692         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 693         int ret = NET_RX_DROP;
 694
 695         /* Must not reply to returned packets */
 696         if (cb->rt_flags & DN_RT_F_RTS)
 697                 goto out;
 698
 699         if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
 700                 switch(cb->nsp_flags & 0x70) {
 701                         case 0x10:
 702                         case 0x60: /* (Retransmitted) Connect Init */
 703                                 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
 704                                 ret = NET_RX_SUCCESS;
 705                                 break;
 706                         case 0x20: /* Connect Confirm */
 707                                 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
 708                                 ret = NET_RX_SUCCESS;
 709                                 break;
 710                 }
 711         }
 712
 713 out:
 714         kfree_skb(skb);
 715         return ret;
 716 }
 717
 718 static int dn_nsp_rx_packet(struct sk_buff *skb)
 719 {
 720         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 721         struct sock *sk = NULL;
 722         unsigned char *ptr = (unsigned char *)skb->data;
 723         unsigned short reason = NSP_REASON_NL;
 724
 725         if (!pskb_may_pull(skb, 2))
 726                 goto free_out;
 727
 728         skb->h.raw    = skb->data;
 729         cb->nsp_flags = *ptr++;
 730
 731         if (decnet_debug_level & 2)
 732                 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
 733
 734         if (cb->nsp_flags & 0x83)
 735                 goto free_out;
 736
 737         /*
 738          * Filter out conninits and useless packet types
 739          */
 740         if ((cb->nsp_flags & 0x0c) == 0x08) {
 741                 switch(cb->nsp_flags & 0x70) {
 742                         case 0x00: /* NOP */
 743                         case 0x70: /* Reserved */
 744                         case 0x50: /* Reserved, Phase II node init */
 745                                 goto free_out;
 746                         case 0x10:
 747                         case 0x60:
 748                                 if (unlikely(cb->rt_flags & DN_RT_F_RTS))
 749                                         goto free_out;
 750                                 sk = dn_find_listener(skb, &reason);
 751                                 goto got_it;
 752                 }
 753         }
 754
 755         if (!pskb_may_pull(skb, 3))
 756                 goto free_out;
 757
 758         /*
 759          * Grab the destination address.
 760          */
 761         cb->dst_port = *(__le16 *)ptr;
 762         cb->src_port = 0;
 763         ptr += 2;
 764
 765         /*
 766          * If not a connack, grab the source address too.
 767          */
 768         if (pskb_may_pull(skb, 5)) {
 769                 cb->src_port = *(__le16 *)ptr;
 770                 ptr += 2;
 771                 skb_pull(skb, 5);
 772         }
 773
 774         /*
 775          * Returned packets...
 776          * Swap src & dst and look up in the normal way.
 777          */
 778         if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
 779                 __le16 tmp = cb->dst_port;
 780                 cb->dst_port = cb->src_port;
 781                 cb->src_port = tmp;
 782                 tmp = cb->dst;
 783                 cb->dst = cb->src;
 784                 cb->src = tmp;
 785         }
 786
 787         /*
 788          * Find the socket to which this skb is destined.
 789          */
 790         sk = dn_find_by_skb(skb);
 791 got_it:
 792         if (sk != NULL) {
 793                 struct dn_scp *scp = DN_SK(sk);
 794
 795                 /* Reset backoff */
 796                 scp->nsp_rxtshift = 0;
 797
 798                 /*
 799                  * We linearize everything except data segments here.
 800                  */
 801                 if (cb->nsp_flags & ~0x60) {
 802                         if (unlikely(skb_linearize(skb)))
 803                                 goto free_out;
 804                 }
 805
 806                 return sk_receive_skb(sk, skb, 0);
 807         }
 808
 809         return dn_nsp_no_socket(skb, reason);
 810
 811 free_out:
 812         kfree_skb(skb);
 813         return NET_RX_DROP;
 814 }
 815
 816 int dn_nsp_rx(struct sk_buff *skb)
 817 {
 818         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
 819 }
 820
 821 /*
 822  * This is the main receive routine for sockets. It is called
 823  * from the above when the socket is not busy, and also from
 824  * sock_release() when there is a backlog queued up.
 825  */
 826 int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 827 {
 828         struct dn_scp *scp = DN_SK(sk);
 829         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 830
 831         if (cb->rt_flags & DN_RT_F_RTS) {
 832                 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
 833                         dn_returned_conn_init(sk, skb);
 834                 else
 835                         kfree_skb(skb);
 836                 return NET_RX_SUCCESS;
 837         }
 838
 839         /*
 840          * Control packet.
 841          */
 842         if ((cb->nsp_flags & 0x0c) == 0x08) {
 843                 switch(cb->nsp_flags & 0x70) {
 844                         case 0x10:
 845                         case 0x60:
 846                                 dn_nsp_conn_init(sk, skb);
 847                                 break;
 848                         case 0x20:
 849                                 dn_nsp_conn_conf(sk, skb);
 850                                 break;
 851                         case 0x30:
 852                                 dn_nsp_disc_init(sk, skb);
 853                                 break;
 854                         case 0x40:
 855                                 dn_nsp_disc_conf(sk, skb);
 856                                 break;
 857                 }
 858
 859         } else if (cb->nsp_flags == 0x24) {
 860                 /*
 861                  * Special for connacks, 'cos they don't have
 862                  * ack data or ack otherdata info.
 863                  */
 864                 dn_nsp_conn_ack(sk, skb);
 865         } else {
 866                 int other = 1;
 867
 868                 /* both data and ack frames can kick a CC socket into RUN */
 869                 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
 870                         scp->state = DN_RUN;
 871                         sk->sk_state = TCP_ESTABLISHED;
 872                         sk->sk_state_change(sk);
 873                 }
 874
 875                 if ((cb->nsp_flags & 0x1c) == 0)
 876                         other = 0;
 877                 if (cb->nsp_flags == 0x04)
 878                         other = 0;
 879
 880                 /*
 881                  * Read out ack data here, this applies equally
 882                  * to data, other data, link serivce and both
 883                  * ack data and ack otherdata.
 884                  */
 885                 dn_process_ack(sk, skb, other);
 886
 887                 /*
 888                  * If we've some sort of data here then call a
 889                  * suitable routine for dealing with it, otherwise
 890                  * the packet is an ack and can be discarded.
 891                  */
 892                 if ((cb->nsp_flags & 0x0c) == 0) {
 893
 894                         if (scp->state != DN_RUN)
 895                                 goto free_out;
 896
 897                         switch(cb->nsp_flags) {
 898                                 case 0x10: /* LS */
 899                                         dn_nsp_linkservice(sk, skb);
 900                                         break;
 901                                 case 0x30: /* OD */
 902                                         dn_nsp_otherdata(sk, skb);
 903                                         break;
 904                                 default:
 905                                         dn_nsp_data(sk, skb);
 906                         }
 907
 908                 } else { /* Ack, chuck it out here */
 909 free_out:
 910                         kfree_skb(skb);
 911                 }
 912         }
 913
 914         return NET_RX_SUCCESS;
 915 }
 916