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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 <linux/slab.h>
61#include <net/sock.h>
62#include <net/tcp_states.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
79extern int decnet_log_martians;
80
81static void dn_log_martian(struct sk_buff *skb, const char *msg)
82{
83 if (decnet_log_martians) {
84 char *devname = skb->dev ? skb->dev->name : "???";
85 struct dn_skb_cb *cb = DN_SKB_CB(skb);
86 net_info_ratelimited("DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
87 msg, devname,
88 le16_to_cpu(cb->src),
89 le16_to_cpu(cb->dst),
90 le16_to_cpu(cb->src_port),
91 le16_to_cpu(cb->dst_port));
92 }
93}
94
95/*
96 * For this function we've flipped the cross-subchannel bit
97 * if the message is an otherdata or linkservice message. Thus
98 * we can use it to work out what to update.
99 */
100static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
101{
102 struct dn_scp *scp = DN_SK(sk);
103 unsigned short type = ((ack >> 12) & 0x0003);
104 int wakeup = 0;
105
106 switch (type) {
107 case 0: /* ACK - Data */
108 if (dn_after(ack, scp->ackrcv_dat)) {
109 scp->ackrcv_dat = ack & 0x0fff;
110 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
111 &scp->data_xmit_queue,
112 ack);
113 }
114 break;
115 case 1: /* NAK - Data */
116 break;
117 case 2: /* ACK - OtherData */
118 if (dn_after(ack, scp->ackrcv_oth)) {
119 scp->ackrcv_oth = ack & 0x0fff;
120 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
121 &scp->other_xmit_queue,
122 ack);
123 }
124 break;
125 case 3: /* NAK - OtherData */
126 break;
127 }
128
129 if (wakeup && !sock_flag(sk, SOCK_DEAD))
130 sk->sk_state_change(sk);
131}
132
133/*
134 * This function is a universal ack processor.
135 */
136static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
137{
138 __le16 *ptr = (__le16 *)skb->data;
139 int len = 0;
140 unsigned short ack;
141
142 if (skb->len < 2)
143 return len;
144
145 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
146 skb_pull(skb, 2);
147 ptr++;
148 len += 2;
149 if ((ack & 0x4000) == 0) {
150 if (oth)
151 ack ^= 0x2000;
152 dn_ack(sk, skb, ack);
153 }
154 }
155
156 if (skb->len < 2)
157 return len;
158
159 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
160 skb_pull(skb, 2);
161 len += 2;
162 if ((ack & 0x4000) == 0) {
163 if (oth)
164 ack ^= 0x2000;
165 dn_ack(sk, skb, ack);
166 }
167 }
168
169 return len;
170}
171
172
173/**
174 * dn_check_idf - Check an image data field format is correct.
175 * @pptr: Pointer to pointer to image data
176 * @len: Pointer to length of image data
177 * @max: The maximum allowed length of the data in the image data field
178 * @follow_on: Check that this many bytes exist beyond the end of the image data
179 *
180 * Returns: 0 if ok, -1 on error
181 */
182static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
183{
184 unsigned char *ptr = *pptr;
185 unsigned char flen = *ptr++;
186
187 (*len)--;
188 if (flen > max)
189 return -1;
190 if ((flen + follow_on) > *len)
191 return -1;
192
193 *len -= flen;
194 *pptr = ptr + flen;
195 return 0;
196}
197
198/*
199 * Table of reason codes to pass back to node which sent us a badly
200 * formed message, plus text messages for the log. A zero entry in
201 * the reason field means "don't reply" otherwise a disc init is sent with
202 * the specified reason code.
203 */
204static struct {
205 unsigned short reason;
206 const char *text;
207} ci_err_table[] = {
208 { 0, "CI: Truncated message" },
209 { NSP_REASON_ID, "CI: Destination username error" },
210 { NSP_REASON_ID, "CI: Destination username type" },
211 { NSP_REASON_US, "CI: Source username error" },
212 { 0, "CI: Truncated at menuver" },
213 { 0, "CI: Truncated before access or user data" },
214 { NSP_REASON_IO, "CI: Access data format error" },
215 { NSP_REASON_IO, "CI: User data format error" }
216};
217
218/*
219 * This function uses a slightly different lookup method
220 * to find its sockets, since it searches on object name/number
221 * rather than port numbers. Various tests are done to ensure that
222 * the incoming data is in the correct format before it is queued to
223 * a socket.
224 */
225static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
226{
227 struct dn_skb_cb *cb = DN_SKB_CB(skb);
228 struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
229 struct sockaddr_dn dstaddr;
230 struct sockaddr_dn srcaddr;
231 unsigned char type = 0;
232 int dstlen;
233 int srclen;
234 unsigned char *ptr;
235 int len;
236 int err = 0;
237 unsigned char menuver;
238
239 memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
240 memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
241
242 /*
243 * 1. Decode & remove message header
244 */
245 cb->src_port = msg->srcaddr;
246 cb->dst_port = msg->dstaddr;
247 cb->services = msg->services;
248 cb->info = msg->info;
249 cb->segsize = le16_to_cpu(msg->segsize);
250
251 if (!pskb_may_pull(skb, sizeof(*msg)))
252 goto err_out;
253
254 skb_pull(skb, sizeof(*msg));
255
256 len = skb->len;
257 ptr = skb->data;
258
259 /*
260 * 2. Check destination end username format
261 */
262 dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
263 err++;
264 if (dstlen < 0)
265 goto err_out;
266
267 err++;
268 if (type > 1)
269 goto err_out;
270
271 len -= dstlen;
272 ptr += dstlen;
273
274 /*
275 * 3. Check source end username format
276 */
277 srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
278 err++;
279 if (srclen < 0)
280 goto err_out;
281
282 len -= srclen;
283 ptr += srclen;
284 err++;
285 if (len < 1)
286 goto err_out;
287
288 menuver = *ptr;
289 ptr++;
290 len--;
291
292 /*
293 * 4. Check that optional data actually exists if menuver says it does
294 */
295 err++;
296 if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
297 goto err_out;
298
299 /*
300 * 5. Check optional access data format
301 */
302 err++;
303 if (menuver & DN_MENUVER_ACC) {
304 if (dn_check_idf(&ptr, &len, 39, 1))
305 goto err_out;
306 if (dn_check_idf(&ptr, &len, 39, 1))
307 goto err_out;
308 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
309 goto err_out;
310 }
311
312 /*
313 * 6. Check optional user data format
314 */
315 err++;
316 if (menuver & DN_MENUVER_USR) {
317 if (dn_check_idf(&ptr, &len, 16, 0))
318 goto err_out;
319 }
320
321 /*
322 * 7. Look up socket based on destination end username
323 */
324 return dn_sklist_find_listener(&dstaddr);
325err_out:
326 dn_log_martian(skb, ci_err_table[err].text);
327 *reason = ci_err_table[err].reason;
328 return NULL;
329}
330
331
332static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
333{
334 if (sk_acceptq_is_full(sk)) {
335 kfree_skb(skb);
336 return;
337 }
338
339 sk->sk_ack_backlog++;
340 skb_queue_tail(&sk->sk_receive_queue, skb);
341 sk->sk_state_change(sk);
342}
343
344static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
345{
346 struct dn_skb_cb *cb = DN_SKB_CB(skb);
347 struct dn_scp *scp = DN_SK(sk);
348 unsigned char *ptr;
349
350 if (skb->len < 4)
351 goto out;
352
353 ptr = skb->data;
354 cb->services = *ptr++;
355 cb->info = *ptr++;
356 cb->segsize = le16_to_cpu(*(__le16 *)ptr);
357
358 if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
359 scp->persist = 0;
360 scp->addrrem = cb->src_port;
361 sk->sk_state = TCP_ESTABLISHED;
362 scp->state = DN_RUN;
363 scp->services_rem = cb->services;
364 scp->info_rem = cb->info;
365 scp->segsize_rem = cb->segsize;
366
367 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
368 scp->max_window = decnet_no_fc_max_cwnd;
369
370 if (skb->len > 0) {
371 u16 dlen = *skb->data;
372 if ((dlen <= 16) && (dlen <= skb->len)) {
373 scp->conndata_in.opt_optl = cpu_to_le16(dlen);
374 skb_copy_from_linear_data_offset(skb, 1,
375 scp->conndata_in.opt_data, dlen);
376 }
377 }
378 dn_nsp_send_link(sk, DN_NOCHANGE, 0);
379 if (!sock_flag(sk, SOCK_DEAD))
380 sk->sk_state_change(sk);
381 }
382
383out:
384 kfree_skb(skb);
385}
386
387static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
388{
389 struct dn_scp *scp = DN_SK(sk);
390
391 if (scp->state == DN_CI) {
392 scp->state = DN_CD;
393 scp->persist = 0;
394 }
395
396 kfree_skb(skb);
397}
398
399static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
400{
401 struct dn_scp *scp = DN_SK(sk);
402 struct dn_skb_cb *cb = DN_SKB_CB(skb);
403 unsigned short reason;
404
405 if (skb->len < 2)
406 goto out;
407
408 reason = le16_to_cpu(*(__le16 *)skb->data);
409 skb_pull(skb, 2);
410
411 scp->discdata_in.opt_status = cpu_to_le16(reason);
412 scp->discdata_in.opt_optl = 0;
413 memset(scp->discdata_in.opt_data, 0, 16);
414
415 if (skb->len > 0) {
416 u16 dlen = *skb->data;
417 if ((dlen <= 16) && (dlen <= skb->len)) {
418 scp->discdata_in.opt_optl = cpu_to_le16(dlen);
419 skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen);
420 }
421 }
422
423 scp->addrrem = cb->src_port;
424 sk->sk_state = TCP_CLOSE;
425
426 switch (scp->state) {
427 case DN_CI:
428 case DN_CD:
429 scp->state = DN_RJ;
430 sk->sk_err = ECONNREFUSED;
431 break;
432 case DN_RUN:
433 sk->sk_shutdown |= SHUTDOWN_MASK;
434 scp->state = DN_DN;
435 break;
436 case DN_DI:
437 scp->state = DN_DIC;
438 break;
439 }
440
441 if (!sock_flag(sk, SOCK_DEAD)) {
442 if (sk->sk_socket->state != SS_UNCONNECTED)
443 sk->sk_socket->state = SS_DISCONNECTING;
444 sk->sk_state_change(sk);
445 }
446
447 /*
448 * It appears that its possible for remote machines to send disc
449 * init messages with no port identifier if we are in the CI and
450 * possibly also the CD state. Obviously we shouldn't reply with
451 * a message if we don't know what the end point is.
452 */
453 if (scp->addrrem) {
454 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
455 }
456 scp->persist_fxn = dn_destroy_timer;
457 scp->persist = dn_nsp_persist(sk);
458
459out:
460 kfree_skb(skb);
461}
462
463/*
464 * disc_conf messages are also called no_resources or no_link
465 * messages depending upon the "reason" field.
466 */
467static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
468{
469 struct dn_scp *scp = DN_SK(sk);
470 unsigned short reason;
471
472 if (skb->len != 2)
473 goto out;
474
475 reason = le16_to_cpu(*(__le16 *)skb->data);
476
477 sk->sk_state = TCP_CLOSE;
478
479 switch (scp->state) {
480 case DN_CI:
481 scp->state = DN_NR;
482 break;
483 case DN_DR:
484 if (reason == NSP_REASON_DC)
485 scp->state = DN_DRC;
486 if (reason == NSP_REASON_NL)
487 scp->state = DN_CN;
488 break;
489 case DN_DI:
490 scp->state = DN_DIC;
491 break;
492 case DN_RUN:
493 sk->sk_shutdown |= SHUTDOWN_MASK;
494 case DN_CC:
495 scp->state = DN_CN;
496 }
497
498 if (!sock_flag(sk, SOCK_DEAD)) {
499 if (sk->sk_socket->state != SS_UNCONNECTED)
500 sk->sk_socket->state = SS_DISCONNECTING;
501 sk->sk_state_change(sk);
502 }
503
504 scp->persist_fxn = dn_destroy_timer;
505 scp->persist = dn_nsp_persist(sk);
506
507out:
508 kfree_skb(skb);
509}
510
511static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
512{
513 struct dn_scp *scp = DN_SK(sk);
514 unsigned short segnum;
515 unsigned char lsflags;
516 signed char fcval;
517 int wake_up = 0;
518 char *ptr = skb->data;
519 unsigned char fctype = scp->services_rem & NSP_FC_MASK;
520
521 if (skb->len != 4)
522 goto out;
523
524 segnum = le16_to_cpu(*(__le16 *)ptr);
525 ptr += 2;
526 lsflags = *(unsigned char *)ptr++;
527 fcval = *ptr;
528
529 /*
530 * Here we ignore erronous packets which should really
531 * should cause a connection abort. It is not critical
532 * for now though.
533 */
534 if (lsflags & 0xf8)
535 goto out;
536
537 if (seq_next(scp->numoth_rcv, segnum)) {
538 seq_add(&scp->numoth_rcv, 1);
539 switch(lsflags & 0x04) { /* FCVAL INT */
540 case 0x00: /* Normal Request */
541 switch(lsflags & 0x03) { /* FCVAL MOD */
542 case 0x00: /* Request count */
543 if (fcval < 0) {
544 unsigned char p_fcval = -fcval;
545 if ((scp->flowrem_dat > p_fcval) &&
546 (fctype == NSP_FC_SCMC)) {
547 scp->flowrem_dat -= p_fcval;
548 }
549 } else if (fcval > 0) {
550 scp->flowrem_dat += fcval;
551 wake_up = 1;
552 }
553 break;
554 case 0x01: /* Stop outgoing data */
555 scp->flowrem_sw = DN_DONTSEND;
556 break;
557 case 0x02: /* Ok to start again */
558 scp->flowrem_sw = DN_SEND;
559 dn_nsp_output(sk);
560 wake_up = 1;
561 }
562 break;
563 case 0x04: /* Interrupt Request */
564 if (fcval > 0) {
565 scp->flowrem_oth += fcval;
566 wake_up = 1;
567 }
568 break;
569 }
570 if (wake_up && !sock_flag(sk, SOCK_DEAD))
571 sk->sk_state_change(sk);
572 }
573
574 dn_nsp_send_oth_ack(sk);
575
576out:
577 kfree_skb(skb);
578}
579
580/*
581 * Copy of sock_queue_rcv_skb (from sock.h) without
582 * bh_lock_sock() (its already held when this is called) which
583 * also allows data and other data to be queued to a socket.
584 */
585static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
586{
587 int err;
588
589 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
590 number of warnings when compiling with -W --ANK
591 */
592 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
593 (unsigned int)sk->sk_rcvbuf) {
594 err = -ENOMEM;
595 goto out;
596 }
597
598 err = sk_filter(sk, skb);
599 if (err)
600 goto out;
601
602 skb_set_owner_r(skb, sk);
603 skb_queue_tail(queue, skb);
604
605 if (!sock_flag(sk, SOCK_DEAD))
606 sk->sk_data_ready(sk);
607out:
608 return err;
609}
610
611static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
612{
613 struct dn_scp *scp = DN_SK(sk);
614 unsigned short segnum;
615 struct dn_skb_cb *cb = DN_SKB_CB(skb);
616 int queued = 0;
617
618 if (skb->len < 2)
619 goto out;
620
621 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
622 skb_pull(skb, 2);
623
624 if (seq_next(scp->numoth_rcv, segnum)) {
625
626 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
627 seq_add(&scp->numoth_rcv, 1);
628 scp->other_report = 0;
629 queued = 1;
630 }
631 }
632
633 dn_nsp_send_oth_ack(sk);
634out:
635 if (!queued)
636 kfree_skb(skb);
637}
638
639static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
640{
641 int queued = 0;
642 unsigned short segnum;
643 struct dn_skb_cb *cb = DN_SKB_CB(skb);
644 struct dn_scp *scp = DN_SK(sk);
645
646 if (skb->len < 2)
647 goto out;
648
649 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
650 skb_pull(skb, 2);
651
652 if (seq_next(scp->numdat_rcv, segnum)) {
653 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
654 seq_add(&scp->numdat_rcv, 1);
655 queued = 1;
656 }
657
658 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
659 scp->flowloc_sw = DN_DONTSEND;
660 dn_nsp_send_link(sk, DN_DONTSEND, 0);
661 }
662 }
663
664 dn_nsp_send_data_ack(sk);
665out:
666 if (!queued)
667 kfree_skb(skb);
668}
669
670/*
671 * If one of our conninit messages is returned, this function
672 * deals with it. It puts the socket into the NO_COMMUNICATION
673 * state.
674 */
675static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
676{
677 struct dn_scp *scp = DN_SK(sk);
678
679 if (scp->state == DN_CI) {
680 scp->state = DN_NC;
681 sk->sk_state = TCP_CLOSE;
682 if (!sock_flag(sk, SOCK_DEAD))
683 sk->sk_state_change(sk);
684 }
685
686 kfree_skb(skb);
687}
688
689static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
690{
691 struct dn_skb_cb *cb = DN_SKB_CB(skb);
692 int ret = NET_RX_DROP;
693
694 /* Must not reply to returned packets */
695 if (cb->rt_flags & DN_RT_F_RTS)
696 goto out;
697
698 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
699 switch (cb->nsp_flags & 0x70) {
700 case 0x10:
701 case 0x60: /* (Retransmitted) Connect Init */
702 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
703 ret = NET_RX_SUCCESS;
704 break;
705 case 0x20: /* Connect Confirm */
706 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
707 ret = NET_RX_SUCCESS;
708 break;
709 }
710 }
711
712out:
713 kfree_skb(skb);
714 return ret;
715}
716
717static int dn_nsp_rx_packet(struct net *net, struct sock *sk2,
718 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_reset_transport_header(skb);
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);
791got_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
811free_out:
812 kfree_skb(skb);
813 return NET_RX_DROP;
814}
815
816int dn_nsp_rx(struct sk_buff *skb)
817{
818 return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
819 &init_net, NULL, skb, skb->dev, NULL,
820 dn_nsp_rx_packet);
821}
822
823/*
824 * This is the main receive routine for sockets. It is called
825 * from the above when the socket is not busy, and also from
826 * sock_release() when there is a backlog queued up.
827 */
828int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
829{
830 struct dn_scp *scp = DN_SK(sk);
831 struct dn_skb_cb *cb = DN_SKB_CB(skb);
832
833 if (cb->rt_flags & DN_RT_F_RTS) {
834 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
835 dn_returned_conn_init(sk, skb);
836 else
837 kfree_skb(skb);
838 return NET_RX_SUCCESS;
839 }
840
841 /*
842 * Control packet.
843 */
844 if ((cb->nsp_flags & 0x0c) == 0x08) {
845 switch (cb->nsp_flags & 0x70) {
846 case 0x10:
847 case 0x60:
848 dn_nsp_conn_init(sk, skb);
849 break;
850 case 0x20:
851 dn_nsp_conn_conf(sk, skb);
852 break;
853 case 0x30:
854 dn_nsp_disc_init(sk, skb);
855 break;
856 case 0x40:
857 dn_nsp_disc_conf(sk, skb);
858 break;
859 }
860
861 } else if (cb->nsp_flags == 0x24) {
862 /*
863 * Special for connacks, 'cos they don't have
864 * ack data or ack otherdata info.
865 */
866 dn_nsp_conn_ack(sk, skb);
867 } else {
868 int other = 1;
869
870 /* both data and ack frames can kick a CC socket into RUN */
871 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
872 scp->state = DN_RUN;
873 sk->sk_state = TCP_ESTABLISHED;
874 sk->sk_state_change(sk);
875 }
876
877 if ((cb->nsp_flags & 0x1c) == 0)
878 other = 0;
879 if (cb->nsp_flags == 0x04)
880 other = 0;
881
882 /*
883 * Read out ack data here, this applies equally
884 * to data, other data, link serivce and both
885 * ack data and ack otherdata.
886 */
887 dn_process_ack(sk, skb, other);
888
889 /*
890 * If we've some sort of data here then call a
891 * suitable routine for dealing with it, otherwise
892 * the packet is an ack and can be discarded.
893 */
894 if ((cb->nsp_flags & 0x0c) == 0) {
895
896 if (scp->state != DN_RUN)
897 goto free_out;
898
899 switch (cb->nsp_flags) {
900 case 0x10: /* LS */
901 dn_nsp_linkservice(sk, skb);
902 break;
903 case 0x30: /* OD */
904 dn_nsp_otherdata(sk, skb);
905 break;
906 default:
907 dn_nsp_data(sk, skb);
908 }
909
910 } else { /* Ack, chuck it out here */
911free_out:
912 kfree_skb(skb);
913 }
914 }
915
916 return NET_RX_SUCCESS;
917}
918
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
71extern int decnet_log_martians;
72
73static 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 */
92static 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 */
128static 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 */
174static 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 */
196static 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 */
217static 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);
317err_out:
318 dn_log_martian(skb, ci_err_table[err].text);
319 *reason = ci_err_table[err].reason;
320 return NULL;
321}
322
323
324static 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
336static 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
375out:
376 kfree_skb(skb);
377}
378
379static 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
391static 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
451out:
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 */
459static 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
500out:
501 kfree_skb(skb);
502}
503
504static 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
569out:
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 */
578static __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);
600out:
601 return err;
602}
603
604static 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);
627out:
628 if (!queued)
629 kfree_skb(skb);
630}
631
632static 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);
658out:
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 */
668static 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
682static 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
705out:
706 kfree_skb(skb);
707 return ret;
708}
709
710static 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);
780got_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
800free_out:
801 kfree_skb(skb);
802 return NET_RX_DROP;
803}
804
805int 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 */
817int 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 */
900free_out:
901 kfree_skb(skb);
902 }
903 }
904
905 return NET_RX_SUCCESS;
906}