1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * DECnet An implementation of the DECnet protocol suite for the LINUX
4 * operating system. DECnet is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * DECnet Network Services Protocol (Input)
8 *
9 * Author: Eduardo Marcelo Serrat <emserrat@geocities.com>
10 *
11 * Changes:
12 *
13 * Steve Whitehouse: Split into dn_nsp_in.c and dn_nsp_out.c from
14 * original dn_nsp.c.
15 * Steve Whitehouse: Updated to work with my new routing architecture.
16 * Steve Whitehouse: Add changes from Eduardo Serrat's patches.
17 * Steve Whitehouse: Put all ack handling code in a common routine.
18 * Steve Whitehouse: Put other common bits into dn_nsp_rx()
19 * Steve Whitehouse: More checks on skb->len to catch bogus packets
20 * Fixed various race conditions and possible nasties.
21 * Steve Whitehouse: Now handles returned conninit frames.
22 * David S. Miller: New socket locking
23 * Steve Whitehouse: Fixed lockup when socket filtering was enabled.
24 * Paul Koning: Fix to push CC sockets into RUN when acks are
25 * received.
26 * Steve Whitehouse:
27 * Patrick Caulfield: Checking conninits for correctness & sending of error
28 * responses.
29 * Steve Whitehouse: Added backlog congestion level return codes.
30 * Patrick Caulfield:
31 * Steve Whitehouse: Added flow control support (outbound)
32 * Steve Whitehouse: Prepare for nonlinear skbs
33 */
34
35 /******************************************************************************
36 (c) 1995-1998 E.M. Serrat emserrat@geocities.com
37
38 *******************************************************************************/
39
40 #include <linux/errno.h>
41 #include <linux/types.h>
42 #include <linux/socket.h>
43 #include <linux/in.h>
44 #include <linux/kernel.h>
45 #include <linux/timer.h>
46 #include <linux/string.h>
47 #include <linux/sockios.h>
48 #include <linux/net.h>
49 #include <linux/netdevice.h>
50 #include <linux/inet.h>
51 #include <linux/route.h>
52 #include <linux/slab.h>
53 #include <net/sock.h>
54 #include <net/tcp_states.h>
55 #include <linux/fcntl.h>
56 #include <linux/mm.h>
57 #include <linux/termios.h>
58 #include <linux/interrupt.h>
59 #include <linux/proc_fs.h>
60 #include <linux/stat.h>
61 #include <linux/init.h>
62 #include <linux/poll.h>
63 #include <linux/netfilter_decnet.h>
64 #include <net/neighbour.h>
65 #include <net/dst.h>
66 #include <net/dn.h>
67 #include <net/dn_nsp.h>
68 #include <net/dn_dev.h>
69 #include <net/dn_route.h>
70
71 extern int decnet_log_martians;
72
73 static void dn_log_martian(struct sk_buff *skb, const char *msg)
74 {
75 if (decnet_log_martians) {
76 char *devname = skb->dev ? skb->dev->name : "???";
77 struct dn_skb_cb *cb = DN_SKB_CB(skb);
78 net_info_ratelimited("DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
79 msg, devname,
80 le16_to_cpu(cb->src),
81 le16_to_cpu(cb->dst),
82 le16_to_cpu(cb->src_port),
83 le16_to_cpu(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 = DN_SK(sk);
95 unsigned short type = ((ack >> 12) & 0x0003);
96 int wakeup = 0;
97
98 switch (type) {
99 case 0: /* ACK - Data */
100 if (dn_after(ack, scp->ackrcv_dat)) {
101 scp->ackrcv_dat = ack & 0x0fff;
102 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
103 &scp->data_xmit_queue,
104 ack);
105 }
106 break;
107 case 1: /* NAK - Data */
108 break;
109 case 2: /* ACK - OtherData */
110 if (dn_after(ack, scp->ackrcv_oth)) {
111 scp->ackrcv_oth = ack & 0x0fff;
112 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
113 &scp->other_xmit_queue,
114 ack);
115 }
116 break;
117 case 3: /* NAK - OtherData */
118 break;
119 }
120
121 if (wakeup && !sock_flag(sk, SOCK_DEAD))
122 sk->sk_state_change(sk);
123 }
124
125 /*
126 * This function is a universal ack processor.
127 */
128 static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
129 {
130 __le16 *ptr = (__le16 *)skb->data;
131 int len = 0;
132 unsigned short ack;
133
134 if (skb->len < 2)
135 return len;
136
137 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
138 skb_pull(skb, 2);
139 ptr++;
140 len += 2;
141 if ((ack & 0x4000) == 0) {
142 if (oth)
143 ack ^= 0x2000;
144 dn_ack(sk, skb, ack);
145 }
146 }
147
148 if (skb->len < 2)
149 return len;
150
151 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
152 skb_pull(skb, 2);
153 len += 2;
154 if ((ack & 0x4000) == 0) {
155 if (oth)
156 ack ^= 0x2000;
157 dn_ack(sk, skb, ack);
158 }
159 }
160
161 return len;
162 }
163
164
165 /**
166 * dn_check_idf - Check an image data field format is correct.
167 * @pptr: Pointer to pointer to image data
168 * @len: Pointer to length of image data
169 * @max: The maximum allowed length of the data in the image data field
170 * @follow_on: Check that this many bytes exist beyond the end of the image data
171 *
172 * Returns: 0 if ok, -1 on error
173 */
174 static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
175 {
176 unsigned char *ptr = *pptr;
177 unsigned char flen = *ptr++;
178
179 (*len)--;
180 if (flen > max)
181 return -1;
182 if ((flen + follow_on) > *len)
183 return -1;
184
185 *len -= flen;
186 *pptr = ptr + flen;
187 return 0;
188 }
189
190 /*
191 * Table of reason codes to pass back to node which sent us a badly
192 * formed message, plus text messages for the log. A zero entry in
193 * the reason field means "don't reply" otherwise a disc init is sent with
194 * the specified reason code.
195 */
196 static struct {
197 unsigned short reason;
198 const char *text;
199 } ci_err_table[] = {
200 { 0, "CI: Truncated message" },
201 { NSP_REASON_ID, "CI: Destination username error" },
202 { NSP_REASON_ID, "CI: Destination username type" },
203 { NSP_REASON_US, "CI: Source username error" },
204 { 0, "CI: Truncated at menuver" },
205 { 0, "CI: Truncated before access or user data" },
206 { NSP_REASON_IO, "CI: Access data format error" },
207 { NSP_REASON_IO, "CI: User data format error" }
208 };
209
210 /*
211 * This function uses a slightly different lookup method
212 * to find its sockets, since it searches on object name/number
213 * rather than port numbers. Various tests are done to ensure that
214 * the incoming data is in the correct format before it is queued to
215 * a socket.
216 */
217 static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
218 {
219 struct dn_skb_cb *cb = DN_SKB_CB(skb);
220 struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
221 struct sockaddr_dn dstaddr;
222 struct sockaddr_dn srcaddr;
223 unsigned char type = 0;
224 int dstlen;
225 int srclen;
226 unsigned char *ptr;
227 int len;
228 int err = 0;
229 unsigned char menuver;
230
231 memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
232 memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
233
234 /*
235 * 1. Decode & remove message header
236 */
237 cb->src_port = msg->srcaddr;
238 cb->dst_port = msg->dstaddr;
239 cb->services = msg->services;
240 cb->info = msg->info;
241 cb->segsize = le16_to_cpu(msg->segsize);
242
243 if (!pskb_may_pull(skb, sizeof(*msg)))
244 goto err_out;
245
246 skb_pull(skb, sizeof(*msg));
247
248 len = skb->len;
249 ptr = skb->data;
250
251 /*
252 * 2. Check destination end username format
253 */
254 dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
255 err++;
256 if (dstlen < 0)
257 goto err_out;
258
259 err++;
260 if (type > 1)
261 goto err_out;
262
263 len -= dstlen;
264 ptr += dstlen;
265
266 /*
267 * 3. Check source end username format
268 */
269 srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
270 err++;
271 if (srclen < 0)
272 goto err_out;
273
274 len -= srclen;
275 ptr += srclen;
276 err++;
277 if (len < 1)
278 goto err_out;
279
280 menuver = *ptr;
281 ptr++;
282 len--;
283
284 /*
285 * 4. Check that optional data actually exists if menuver says it does
286 */
287 err++;
288 if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
289 goto err_out;
290
291 /*
292 * 5. Check optional access data format
293 */
294 err++;
295 if (menuver & DN_MENUVER_ACC) {
296 if (dn_check_idf(&ptr, &len, 39, 1))
297 goto err_out;
298 if (dn_check_idf(&ptr, &len, 39, 1))
299 goto err_out;
300 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
301 goto err_out;
302 }
303
304 /*
305 * 6. Check optional user data format
306 */
307 err++;
308 if (menuver & DN_MENUVER_USR) {
309 if (dn_check_idf(&ptr, &len, 16, 0))
310 goto err_out;
311 }
312
313 /*
314 * 7. Look up socket based on destination end username
315 */
316 return dn_sklist_find_listener(&dstaddr);
317 err_out:
318 dn_log_martian(skb, ci_err_table[err].text);
319 *reason = ci_err_table[err].reason;
320 return NULL;
321 }
322
323
324 static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
325 {
326 if (sk_acceptq_is_full(sk)) {
327 kfree_skb(skb);
328 return;
329 }
330
331 sk_acceptq_added(sk);
332 skb_queue_tail(&sk->sk_receive_queue, skb);
333 sk->sk_state_change(sk);
334 }
335
336 static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
337 {
338 struct dn_skb_cb *cb = DN_SKB_CB(skb);
339 struct dn_scp *scp = DN_SK(sk);
340 unsigned char *ptr;
341
342 if (skb->len < 4)
343 goto out;
344
345 ptr = skb->data;
346 cb->services = *ptr++;
347 cb->info = *ptr++;
348 cb->segsize = le16_to_cpu(*(__le16 *)ptr);
349
350 if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
351 scp->persist = 0;
352 scp->addrrem = cb->src_port;
353 sk->sk_state = TCP_ESTABLISHED;
354 scp->state = DN_RUN;
355 scp->services_rem = cb->services;
356 scp->info_rem = cb->info;
357 scp->segsize_rem = cb->segsize;
358
359 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
360 scp->max_window = decnet_no_fc_max_cwnd;
361
362 if (skb->len > 0) {
363 u16 dlen = *skb->data;
364 if ((dlen <= 16) && (dlen <= skb->len)) {
365 scp->conndata_in.opt_optl = cpu_to_le16(dlen);
366 skb_copy_from_linear_data_offset(skb, 1,
367 scp->conndata_in.opt_data, dlen);
368 }
369 }
370 dn_nsp_send_link(sk, DN_NOCHANGE, 0);
371 if (!sock_flag(sk, SOCK_DEAD))
372 sk->sk_state_change(sk);
373 }
374
375 out:
376 kfree_skb(skb);
377 }
378
379 static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
380 {
381 struct dn_scp *scp = DN_SK(sk);
382
383 if (scp->state == DN_CI) {
384 scp->state = DN_CD;
385 scp->persist = 0;
386 }
387
388 kfree_skb(skb);
389 }
390
391 static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
392 {
393 struct dn_scp *scp = DN_SK(sk);
394 struct dn_skb_cb *cb = DN_SKB_CB(skb);
395 unsigned short reason;
396
397 if (skb->len < 2)
398 goto out;
399
400 reason = le16_to_cpu(*(__le16 *)skb->data);
401 skb_pull(skb, 2);
402
403 scp->discdata_in.opt_status = cpu_to_le16(reason);
404 scp->discdata_in.opt_optl = 0;
405 memset(scp->discdata_in.opt_data, 0, 16);
406
407 if (skb->len > 0) {
408 u16 dlen = *skb->data;
409 if ((dlen <= 16) && (dlen <= skb->len)) {
410 scp->discdata_in.opt_optl = cpu_to_le16(dlen);
411 skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen);
412 }
413 }
414
415 scp->addrrem = cb->src_port;
416 sk->sk_state = TCP_CLOSE;
417
418 switch (scp->state) {
419 case DN_CI:
420 case DN_CD:
421 scp->state = DN_RJ;
422 sk->sk_err = ECONNREFUSED;
423 break;
424 case DN_RUN:
425 sk->sk_shutdown |= SHUTDOWN_MASK;
426 scp->state = DN_DN;
427 break;
428 case DN_DI:
429 scp->state = DN_DIC;
430 break;
431 }
432
433 if (!sock_flag(sk, SOCK_DEAD)) {
434 if (sk->sk_socket->state != SS_UNCONNECTED)
435 sk->sk_socket->state = SS_DISCONNECTING;
436 sk->sk_state_change(sk);
437 }
438
439 /*
440 * It appears that its possible for remote machines to send disc
441 * init messages with no port identifier if we are in the CI and
442 * possibly also the CD state. Obviously we shouldn't reply with
443 * a message if we don't know what the end point is.
444 */
445 if (scp->addrrem) {
446 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
447 }
448 scp->persist_fxn = dn_destroy_timer;
449 scp->persist = dn_nsp_persist(sk);
450
451 out:
452 kfree_skb(skb);
453 }
454
455 /*
456 * disc_conf messages are also called no_resources or no_link
457 * messages depending upon the "reason" field.
458 */
459 static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
460 {
461 struct dn_scp *scp = DN_SK(sk);
462 unsigned short reason;
463
464 if (skb->len != 2)
465 goto out;
466
467 reason = le16_to_cpu(*(__le16 *)skb->data);
468
469 sk->sk_state = TCP_CLOSE;
470
471 switch (scp->state) {
472 case DN_CI:
473 scp->state = DN_NR;
474 break;
475 case DN_DR:
476 if (reason == NSP_REASON_DC)
477 scp->state = DN_DRC;
478 if (reason == NSP_REASON_NL)
479 scp->state = DN_CN;
480 break;
481 case DN_DI:
482 scp->state = DN_DIC;
483 break;
484 case DN_RUN:
485 sk->sk_shutdown |= SHUTDOWN_MASK;
486 fallthrough;
487 case DN_CC:
488 scp->state = DN_CN;
489 }
490
491 if (!sock_flag(sk, SOCK_DEAD)) {
492 if (sk->sk_socket->state != SS_UNCONNECTED)
493 sk->sk_socket->state = SS_DISCONNECTING;
494 sk->sk_state_change(sk);
495 }
496
497 scp->persist_fxn = dn_destroy_timer;
498 scp->persist = dn_nsp_persist(sk);
499
500 out:
501 kfree_skb(skb);
502 }
503
504 static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
505 {
506 struct dn_scp *scp = DN_SK(sk);
507 unsigned short segnum;
508 unsigned char lsflags;
509 signed char fcval;
510 int wake_up = 0;
511 char *ptr = skb->data;
512 unsigned char fctype = scp->services_rem & NSP_FC_MASK;
513
514 if (skb->len != 4)
515 goto out;
516
517 segnum = le16_to_cpu(*(__le16 *)ptr);
518 ptr += 2;
519 lsflags = *(unsigned char *)ptr++;
520 fcval = *ptr;
521
522 /*
523 * Here we ignore erroneous packets which should really
524 * should cause a connection abort. It is not critical
525 * for now though.
526 */
527 if (lsflags & 0xf8)
528 goto out;
529
530 if (seq_next(scp->numoth_rcv, segnum)) {
531 seq_add(&scp->numoth_rcv, 1);
532 switch(lsflags & 0x04) { /* FCVAL INT */
533 case 0x00: /* Normal Request */
534 switch(lsflags & 0x03) { /* FCVAL MOD */
535 case 0x00: /* Request count */
536 if (fcval < 0) {
537 unsigned char p_fcval = -fcval;
538 if ((scp->flowrem_dat > p_fcval) &&
539 (fctype == NSP_FC_SCMC)) {
540 scp->flowrem_dat -= p_fcval;
541 }
542 } else if (fcval > 0) {
543 scp->flowrem_dat += fcval;
544 wake_up = 1;
545 }
546 break;
547 case 0x01: /* Stop outgoing data */
548 scp->flowrem_sw = DN_DONTSEND;
549 break;
550 case 0x02: /* Ok to start again */
551 scp->flowrem_sw = DN_SEND;
552 dn_nsp_output(sk);
553 wake_up = 1;
554 }
555 break;
556 case 0x04: /* Interrupt Request */
557 if (fcval > 0) {
558 scp->flowrem_oth += fcval;
559 wake_up = 1;
560 }
561 break;
562 }
563 if (wake_up && !sock_flag(sk, SOCK_DEAD))
564 sk->sk_state_change(sk);
565 }
566
567 dn_nsp_send_oth_ack(sk);
568
569 out:
570 kfree_skb(skb);
571 }
572
573 /*
574 * Copy of sock_queue_rcv_skb (from sock.h) without
575 * bh_lock_sock() (its already held when this is called) which
576 * also allows data and other data to be queued to a socket.
577 */
578 static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
579 {
580 int err;
581
582 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
583 number of warnings when compiling with -W --ANK
584 */
585 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
586 (unsigned int)sk->sk_rcvbuf) {
587 err = -ENOMEM;
588 goto out;
589 }
590
591 err = sk_filter(sk, skb);
592 if (err)
593 goto out;
594
595 skb_set_owner_r(skb, sk);
596 skb_queue_tail(queue, skb);
597
598 if (!sock_flag(sk, SOCK_DEAD))
599 sk->sk_data_ready(sk);
600 out:
601 return err;
602 }
603
604 static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
605 {
606 struct dn_scp *scp = DN_SK(sk);
607 unsigned short segnum;
608 struct dn_skb_cb *cb = DN_SKB_CB(skb);
609 int queued = 0;
610
611 if (skb->len < 2)
612 goto out;
613
614 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
615 skb_pull(skb, 2);
616
617 if (seq_next(scp->numoth_rcv, segnum)) {
618
619 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
620 seq_add(&scp->numoth_rcv, 1);
621 scp->other_report = 0;
622 queued = 1;
623 }
624 }
625
626 dn_nsp_send_oth_ack(sk);
627 out:
628 if (!queued)
629 kfree_skb(skb);
630 }
631
632 static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
633 {
634 int queued = 0;
635 unsigned short segnum;
636 struct dn_skb_cb *cb = DN_SKB_CB(skb);
637 struct dn_scp *scp = DN_SK(sk);
638
639 if (skb->len < 2)
640 goto out;
641
642 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
643 skb_pull(skb, 2);
644
645 if (seq_next(scp->numdat_rcv, segnum)) {
646 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
647 seq_add(&scp->numdat_rcv, 1);
648 queued = 1;
649 }
650
651 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
652 scp->flowloc_sw = DN_DONTSEND;
653 dn_nsp_send_link(sk, DN_DONTSEND, 0);
654 }
655 }
656
657 dn_nsp_send_data_ack(sk);
658 out:
659 if (!queued)
660 kfree_skb(skb);
661 }
662
663 /*
664 * If one of our conninit messages is returned, this function
665 * deals with it. It puts the socket into the NO_COMMUNICATION
666 * state.
667 */
668 static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
669 {
670 struct dn_scp *scp = DN_SK(sk);
671
672 if (scp->state == DN_CI) {
673 scp->state = DN_NC;
674 sk->sk_state = TCP_CLOSE;
675 if (!sock_flag(sk, SOCK_DEAD))
676 sk->sk_state_change(sk);
677 }
678
679 kfree_skb(skb);
680 }
681
682 static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
683 {
684 struct dn_skb_cb *cb = DN_SKB_CB(skb);
685 int ret = NET_RX_DROP;
686
687 /* Must not reply to returned packets */
688 if (cb->rt_flags & DN_RT_F_RTS)
689 goto out;
690
691 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
692 switch (cb->nsp_flags & 0x70) {
693 case 0x10:
694 case 0x60: /* (Retransmitted) Connect Init */
695 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
696 ret = NET_RX_SUCCESS;
697 break;
698 case 0x20: /* Connect Confirm */
699 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
700 ret = NET_RX_SUCCESS;
701 break;
702 }
703 }
704
705 out:
706 kfree_skb(skb);
707 return ret;
708 }
709
710 static int dn_nsp_rx_packet(struct net *net, struct sock *sk2,
711 struct sk_buff *skb)
712 {
713 struct dn_skb_cb *cb = DN_SKB_CB(skb);
714 struct sock *sk = NULL;
715 unsigned char *ptr = (unsigned char *)skb->data;
716 unsigned short reason = NSP_REASON_NL;
717
718 if (!pskb_may_pull(skb, 2))
719 goto free_out;
720
721 skb_reset_transport_header(skb);
722 cb->nsp_flags = *ptr++;
723
724 if (decnet_debug_level & 2)
725 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
726
727 if (cb->nsp_flags & 0x83)
728 goto free_out;
729
730 /*
731 * Filter out conninits and useless packet types
732 */
733 if ((cb->nsp_flags & 0x0c) == 0x08) {
734 switch (cb->nsp_flags & 0x70) {
735 case 0x00: /* NOP */
736 case 0x70: /* Reserved */
737 case 0x50: /* Reserved, Phase II node init */
738 goto free_out;
739 case 0x10:
740 case 0x60:
741 if (unlikely(cb->rt_flags & DN_RT_F_RTS))
742 goto free_out;
743 sk = dn_find_listener(skb, &reason);
744 goto got_it;
745 }
746 }
747
748 if (!pskb_may_pull(skb, 3))
749 goto free_out;
750
751 /*
752 * Grab the destination address.
753 */
754 cb->dst_port = *(__le16 *)ptr;
755 cb->src_port = 0;
756 ptr += 2;
757
758 /*
759 * If not a connack, grab the source address too.
760 */
761 if (pskb_may_pull(skb, 5)) {
762 cb->src_port = *(__le16 *)ptr;
763 ptr += 2;
764 skb_pull(skb, 5);
765 }
766
767 /*
768 * Returned packets...
769 * Swap src & dst and look up in the normal way.
770 */
771 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
772 swap(cb->dst_port, cb->src_port);
773 swap(cb->dst, cb->src);
774 }
775
776 /*
777 * Find the socket to which this skb is destined.
778 */
779 sk = dn_find_by_skb(skb);
780 got_it:
781 if (sk != NULL) {
782 struct dn_scp *scp = DN_SK(sk);
783
784 /* Reset backoff */
785 scp->nsp_rxtshift = 0;
786
787 /*
788 * We linearize everything except data segments here.
789 */
790 if (cb->nsp_flags & ~0x60) {
791 if (unlikely(skb_linearize(skb)))
792 goto free_out;
793 }
794
795 return sk_receive_skb(sk, skb, 0);
796 }
797
798 return dn_nsp_no_socket(skb, reason);
799
800 free_out:
801 kfree_skb(skb);
802 return NET_RX_DROP;
803 }
804
805 int dn_nsp_rx(struct sk_buff *skb)
806 {
807 return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
808 &init_net, NULL, skb, skb->dev, NULL,
809 dn_nsp_rx_packet);
810 }
811
812 /*
813 * This is the main receive routine for sockets. It is called
814 * from the above when the socket is not busy, and also from
815 * sock_release() when there is a backlog queued up.
816 */
817 int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
818 {
819 struct dn_scp *scp = DN_SK(sk);
820 struct dn_skb_cb *cb = DN_SKB_CB(skb);
821
822 if (cb->rt_flags & DN_RT_F_RTS) {
823 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
824 dn_returned_conn_init(sk, skb);
825 else
826 kfree_skb(skb);
827 return NET_RX_SUCCESS;
828 }
829
830 /*
831 * Control packet.
832 */
833 if ((cb->nsp_flags & 0x0c) == 0x08) {
834 switch (cb->nsp_flags & 0x70) {
835 case 0x10:
836 case 0x60:
837 dn_nsp_conn_init(sk, skb);
838 break;
839 case 0x20:
840 dn_nsp_conn_conf(sk, skb);
841 break;
842 case 0x30:
843 dn_nsp_disc_init(sk, skb);
844 break;
845 case 0x40:
846 dn_nsp_disc_conf(sk, skb);
847 break;
848 }
849
850 } else if (cb->nsp_flags == 0x24) {
851 /*
852 * Special for connacks, 'cos they don't have
853 * ack data or ack otherdata info.
854 */
855 dn_nsp_conn_ack(sk, skb);
856 } else {
857 int other = 1;
858
859 /* both data and ack frames can kick a CC socket into RUN */
860 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
861 scp->state = DN_RUN;
862 sk->sk_state = TCP_ESTABLISHED;
863 sk->sk_state_change(sk);
864 }
865
866 if ((cb->nsp_flags & 0x1c) == 0)
867 other = 0;
868 if (cb->nsp_flags == 0x04)
869 other = 0;
870
871 /*
872 * Read out ack data here, this applies equally
873 * to data, other data, link service and both
874 * ack data and ack otherdata.
875 */
876 dn_process_ack(sk, skb, other);
877
878 /*
879 * If we've some sort of data here then call a
880 * suitable routine for dealing with it, otherwise
881 * the packet is an ack and can be discarded.
882 */
883 if ((cb->nsp_flags & 0x0c) == 0) {
884
885 if (scp->state != DN_RUN)
886 goto free_out;
887
888 switch (cb->nsp_flags) {
889 case 0x10: /* LS */
890 dn_nsp_linkservice(sk, skb);
891 break;
892 case 0x30: /* OD */
893 dn_nsp_otherdata(sk, skb);
894 break;
895 default:
896 dn_nsp_data(sk, skb);
897 }
898
899 } else { /* Ack, chuck it out here */
900 free_out:
901 kfree_skb(skb);
902 }
903 }
904
905 return NET_RX_SUCCESS;
906 }
907
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