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netfilter: ipv6: use NFPROTO values for NF_HOOK invocation
[linux-2.6-block.git] / net / decnet / dn_nsp_in.c
CommitLineData
1da177e4
LT		 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
429eb0fa 36
1da177e4
LT		 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
1da177e4
LT		 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>
1da177e4
LT		 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>
c752f073 61#include <net/tcp_states.h>
1da177e4
LT		 62#include <asm/system.h>
63#include <linux/fcntl.h>
64#include <linux/mm.h>
429eb0fa 65#include <linux/termios.h>
1da177e4
LT		 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 && net_ratelimit()) {
84 char *devname = skb->dev ? skb->dev->name : "???";
85 struct dn_skb_cb *cb = DN_SKB_CB(skb);
c4106aa8
HH		 86 printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
87 msg, devname, le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
88 le16_to_cpu(cb->src_port), le16_to_cpu(cb->dst_port));
1da177e4
LT		 89 }
90}
91
92/*
93 * For this function we've flipped the cross-subchannel bit
94 * if the message is an otherdata or linkservice message. Thus
95 * we can use it to work out what to update.
96 */
97static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
98{
99 struct dn_scp *scp = DN_SK(sk);
100 unsigned short type = ((ack >> 12) & 0x0003);
101 int wakeup = 0;
102
103 switch(type) {
104 case 0: /* ACK - Data */
105 if (dn_after(ack, scp->ackrcv_dat)) {
106 scp->ackrcv_dat = ack & 0x0fff;
107 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
108 }
109 break;
110 case 1: /* NAK - Data */
111 break;
112 case 2: /* ACK - OtherData */
113 if (dn_after(ack, scp->ackrcv_oth)) {
114 scp->ackrcv_oth = ack & 0x0fff;
115 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
116 }
117 break;
118 case 3: /* NAK - OtherData */
119 break;
120 }
121
122 if (wakeup && !sock_flag(sk, SOCK_DEAD))
123 sk->sk_state_change(sk);
124}
125
126/*
127 * This function is a universal ack processor.
128 */
129static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
130{
c4ea94ab 131 __le16 *ptr = (__le16 *)skb->data;
1da177e4
LT		 132 int len = 0;
133 unsigned short ack;
134
135 if (skb->len < 2)
136 return len;
137
c4106aa8 138 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
1da177e4
LT		 139 skb_pull(skb, 2);
140 ptr++;
141 len += 2;
142 if ((ack & 0x4000) == 0) {
429eb0fa 143 if (oth)
1da177e4
LT		 144 ack ^= 0x2000;
145 dn_ack(sk, skb, ack);
146 }
147 }
148
149 if (skb->len < 2)
150 return len;
151
c4106aa8 152 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
1da177e4
LT		 153 skb_pull(skb, 2);
154 len += 2;
155 if ((ack & 0x4000) == 0) {
429eb0fa 156 if (oth)
1da177e4
LT		 157 ack ^= 0x2000;
158 dn_ack(sk, skb, ack);
159 }
160 }
161
162 return len;
163}
164
165
166/**
167 * dn_check_idf - Check an image data field format is correct.
168 * @pptr: Pointer to pointer to image data
169 * @len: Pointer to length of image data
170 * @max: The maximum allowed length of the data in the image data field
171 * @follow_on: Check that this many bytes exist beyond the end of the image data
172 *
173 * Returns: 0 if ok, -1 on error
174 */
175static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
176{
177 unsigned char *ptr = *pptr;
178 unsigned char flen = *ptr++;
179
180 (*len)--;
181 if (flen > max)
182 return -1;
183 if ((flen + follow_on) > *len)
184 return -1;
185
186 *len -= flen;
187 *pptr = ptr + flen;
188 return 0;
189}
190
191/*
192 * Table of reason codes to pass back to node which sent us a badly
193 * formed message, plus text messages for the log. A zero entry in
194 * the reason field means "don't reply" otherwise a disc init is sent with
195 * the specified reason code.
196 */
197static struct {
198 unsigned short reason;
199 const char *text;
200} ci_err_table[] = {
201 { 0, "CI: Truncated message" },
202 { NSP_REASON_ID, "CI: Destination username error" },
203 { NSP_REASON_ID, "CI: Destination username type" },
204 { NSP_REASON_US, "CI: Source username error" },
205 { 0, "CI: Truncated at menuver" },
206 { 0, "CI: Truncated before access or user data" },
207 { NSP_REASON_IO, "CI: Access data format error" },
208 { NSP_REASON_IO, "CI: User data format error" }
209};
210
211/*
212 * This function uses a slightly different lookup method
213 * to find its sockets, since it searches on object name/number
214 * rather than port numbers. Various tests are done to ensure that
215 * the incoming data is in the correct format before it is queued to
216 * a socket.
217 */
218static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
219{
220 struct dn_skb_cb *cb = DN_SKB_CB(skb);
221 struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
222 struct sockaddr_dn dstaddr;
223 struct sockaddr_dn srcaddr;
224 unsigned char type = 0;
225 int dstlen;
226 int srclen;
227 unsigned char *ptr;
228 int len;
229 int err = 0;
230 unsigned char menuver;
231
232 memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
233 memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
234
235 /*
236 * 1. Decode & remove message header
237 */
238 cb->src_port = msg->srcaddr;
239 cb->dst_port = msg->dstaddr;
240 cb->services = msg->services;
241 cb->info = msg->info;
c4106aa8 242 cb->segsize = le16_to_cpu(msg->segsize);
1da177e4
LT		 243
244 if (!pskb_may_pull(skb, sizeof(*msg)))
245 goto err_out;
246
247 skb_pull(skb, sizeof(*msg));
248
249 len = skb->len;
250 ptr = skb->data;
251
252 /*
253 * 2. Check destination end username format
254 */
255 dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
256 err++;
257 if (dstlen < 0)
258 goto err_out;
259
260 err++;
261 if (type > 1)
262 goto err_out;
263
264 len -= dstlen;
265 ptr += dstlen;
266
267 /*
268 * 3. Check source end username format
269 */
270 srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
271 err++;
272 if (srclen < 0)
273 goto err_out;
274
275 len -= srclen;
276 ptr += srclen;
277 err++;
278 if (len < 1)
279 goto err_out;
280
281 menuver = *ptr;
282 ptr++;
283 len--;
284
285 /*
286 * 4. Check that optional data actually exists if menuver says it does
287 */
288 err++;
289 if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
290 goto err_out;
291
292 /*
293 * 5. Check optional access data format
294 */
295 err++;
296 if (menuver & DN_MENUVER_ACC) {
297 if (dn_check_idf(&ptr, &len, 39, 1))
298 goto err_out;
299 if (dn_check_idf(&ptr, &len, 39, 1))
300 goto err_out;
301 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
302 goto err_out;
303 }
304
305 /*
306 * 6. Check optional user data format
307 */
308 err++;
309 if (menuver & DN_MENUVER_USR) {
310 if (dn_check_idf(&ptr, &len, 16, 0))
311 goto err_out;
312 }
313
314 /*
315 * 7. Look up socket based on destination end username
316 */
317 return dn_sklist_find_listener(&dstaddr);
318err_out:
319 dn_log_martian(skb, ci_err_table[err].text);
320 *reason = ci_err_table[err].reason;
321 return NULL;
322}
323
324
325static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
326{
327 if (sk_acceptq_is_full(sk)) {
328 kfree_skb(skb);
329 return;
330 }
331
332 sk->sk_ack_backlog++;
333 skb_queue_tail(&sk->sk_receive_queue, skb);
334 sk->sk_state_change(sk);
335}
336
337static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
338{
339 struct dn_skb_cb *cb = DN_SKB_CB(skb);
340 struct dn_scp *scp = DN_SK(sk);
341 unsigned char *ptr;
342
343 if (skb->len < 4)
344 goto out;
345
346 ptr = skb->data;
347 cb->services = *ptr++;
348 cb->info = *ptr++;
c4106aa8 349 cb->segsize = le16_to_cpu(*(__le16 *)ptr);
1da177e4
LT		 350
351 if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
352 scp->persist = 0;
429eb0fa
YH		 353 scp->addrrem = cb->src_port;
354 sk->sk_state = TCP_ESTABLISHED;
355 scp->state = DN_RUN;
1da177e4
LT		 356 scp->services_rem = cb->services;
357 scp->info_rem = cb->info;
358 scp->segsize_rem = cb->segsize;
359
360 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
361 scp->max_window = decnet_no_fc_max_cwnd;
362
363 if (skb->len > 0) {
375d9d71 364 u16 dlen = *skb->data;
1da177e4 365 if ((dlen <= 16) && (dlen <= skb->len)) {
c4106aa8 366 scp->conndata_in.opt_optl = cpu_to_le16(dlen);
d626f62b
ACM		 367 skb_copy_from_linear_data_offset(skb, 1,
368 scp->conndata_in.opt_data, dlen);
1da177e4
LT		 369 }
370 }
429eb0fa
YH		 371 dn_nsp_send_link(sk, DN_NOCHANGE, 0);
372 if (!sock_flag(sk, SOCK_DEAD))
373 sk->sk_state_change(sk);
374 }
1da177e4
LT		 375
376out:
429eb0fa 377 kfree_skb(skb);
1da177e4
LT		 378}
379
380static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
381{
382 struct dn_scp *scp = DN_SK(sk);
383
384 if (scp->state == DN_CI) {
385 scp->state = DN_CD;
386 scp->persist = 0;
387 }
388
389 kfree_skb(skb);
390}
391
392static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
393{
394 struct dn_scp *scp = DN_SK(sk);
395 struct dn_skb_cb *cb = DN_SKB_CB(skb);
396 unsigned short reason;
397
398 if (skb->len < 2)
399 goto out;
400
c4106aa8 401 reason = le16_to_cpu(*(__le16 *)skb->data);
1da177e4
LT		 402 skb_pull(skb, 2);
403
c4106aa8 404 scp->discdata_in.opt_status = cpu_to_le16(reason);
1da177e4
LT		 405 scp->discdata_in.opt_optl = 0;
406 memset(scp->discdata_in.opt_data, 0, 16);
407
408 if (skb->len > 0) {
375d9d71 409 u16 dlen = *skb->data;
1da177e4 410 if ((dlen <= 16) && (dlen <= skb->len)) {
c4106aa8 411 scp->discdata_in.opt_optl = cpu_to_le16(dlen);
d626f62b 412 skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen);
1da177e4
LT		 413 }
414 }
415
416 scp->addrrem = cb->src_port;
417 sk->sk_state = TCP_CLOSE;
418
419 switch(scp->state) {
420 case DN_CI:
421 case DN_CD:
422 scp->state = DN_RJ;
423 sk->sk_err = ECONNREFUSED;
424 break;
425 case DN_RUN:
426 sk->sk_shutdown |= SHUTDOWN_MASK;
427 scp->state = DN_DN;
428 break;
429 case DN_DI:
430 scp->state = DN_DIC;
431 break;
432 }
433
434 if (!sock_flag(sk, SOCK_DEAD)) {
435 if (sk->sk_socket->state != SS_UNCONNECTED)
436 sk->sk_socket->state = SS_DISCONNECTING;
437 sk->sk_state_change(sk);
438 }
439
429eb0fa 440 /*
1da177e4
LT		 441 * It appears that its possible for remote machines to send disc
442 * init messages with no port identifier if we are in the CI and
443 * possibly also the CD state. Obviously we shouldn't reply with
444 * a message if we don't know what the end point is.
445 */
446 if (scp->addrrem) {
447 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
448 }
449 scp->persist_fxn = dn_destroy_timer;
450 scp->persist = dn_nsp_persist(sk);
451
452out:
453 kfree_skb(skb);
454}
455
456/*
457 * disc_conf messages are also called no_resources or no_link
458 * messages depending upon the "reason" field.
459 */
460static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
461{
462 struct dn_scp *scp = DN_SK(sk);
463 unsigned short reason;
464
465 if (skb->len != 2)
466 goto out;
467
c4106aa8 468 reason = le16_to_cpu(*(__le16 *)skb->data);
1da177e4
LT		 469
470 sk->sk_state = TCP_CLOSE;
471
472 switch(scp->state) {
473 case DN_CI:
474 scp->state = DN_NR;
475 break;
476 case DN_DR:
477 if (reason == NSP_REASON_DC)
478 scp->state = DN_DRC;
479 if (reason == NSP_REASON_NL)
480 scp->state = DN_CN;
481 break;
482 case DN_DI:
483 scp->state = DN_DIC;
484 break;
485 case DN_RUN:
486 sk->sk_shutdown |= SHUTDOWN_MASK;
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
c4106aa8 517 segnum = le16_to_cpu(*(__le16 *)ptr);
1da177e4
LT		 518 ptr += 2;
519 lsflags = *(unsigned char *)ptr++;
520 fcval = *ptr;
521
522 /*
523 * Here we ignore erronous packets which should really
429eb0fa 524 * should cause a connection abort. It is not critical
1da177e4
LT		 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 */
429eb0fa 535 case 0x00: /* Request count */
1da177e4
LT		 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 }
429eb0fa 546 break;
1da177e4
LT		 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;
429eb0fa 562 }
1da177e4
LT		 563 if (wake_up && !sock_flag(sk, SOCK_DEAD))
564 sk->sk_state_change(sk);
429eb0fa 565 }
1da177e4
LT		 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;
9948bb6a 581 int skb_len;
429eb0fa
YH		 582
583 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
584 number of warnings when compiling with -W --ANK
585 */
586 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
1da177e4 587 (unsigned)sk->sk_rcvbuf) {
429eb0fa
YH		 588 err = -ENOMEM;
589 goto out;
590 }
1da177e4 591
fda9ef5d 592 err = sk_filter(sk, skb);
1da177e4
LT		 593 if (err)
594 goto out;
595
9948bb6a 596 skb_len = skb->len;
429eb0fa
YH		 597 skb_set_owner_r(skb, sk);
598 skb_queue_tail(queue, skb);
1da177e4 599
9948bb6a
SW		 600 if (!sock_flag(sk, SOCK_DEAD))
601 sk->sk_data_ready(sk, skb_len);
1da177e4 602out:
429eb0fa 603 return err;
1da177e4
LT		 604}
605
606static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
607{
608 struct dn_scp *scp = DN_SK(sk);
609 unsigned short segnum;
610 struct dn_skb_cb *cb = DN_SKB_CB(skb);
611 int queued = 0;
612
613 if (skb->len < 2)
614 goto out;
615
c4106aa8 616 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
1da177e4
LT		 617 skb_pull(skb, 2);
618
619 if (seq_next(scp->numoth_rcv, segnum)) {
620
621 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
622 seq_add(&scp->numoth_rcv, 1);
623 scp->other_report = 0;
624 queued = 1;
625 }
626 }
627
628 dn_nsp_send_oth_ack(sk);
629out:
630 if (!queued)
631 kfree_skb(skb);
632}
633
634static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
635{
636 int queued = 0;
637 unsigned short segnum;
638 struct dn_skb_cb *cb = DN_SKB_CB(skb);
639 struct dn_scp *scp = DN_SK(sk);
640
641 if (skb->len < 2)
642 goto out;
643
c4106aa8 644 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
1da177e4
LT		 645 skb_pull(skb, 2);
646
647 if (seq_next(scp->numdat_rcv, segnum)) {
429eb0fa 648 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
1da177e4 649 seq_add(&scp->numdat_rcv, 1);
429eb0fa
YH		 650 queued = 1;
651 }
1da177e4
LT		 652
653 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
654 scp->flowloc_sw = DN_DONTSEND;
655 dn_nsp_send_link(sk, DN_DONTSEND, 0);
656 }
429eb0fa 657 }
1da177e4
LT		 658
659 dn_nsp_send_data_ack(sk);
660out:
661 if (!queued)
662 kfree_skb(skb);
663}
664
665/*
666 * If one of our conninit messages is returned, this function
667 * deals with it. It puts the socket into the NO_COMMUNICATION
668 * state.
669 */
670static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
671{
672 struct dn_scp *scp = DN_SK(sk);
673
674 if (scp->state == DN_CI) {
675 scp->state = DN_NC;
676 sk->sk_state = TCP_CLOSE;
677 if (!sock_flag(sk, SOCK_DEAD))
678 sk->sk_state_change(sk);
679 }
680
681 kfree_skb(skb);
682}
683
684static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
685{
686 struct dn_skb_cb *cb = DN_SKB_CB(skb);
687 int ret = NET_RX_DROP;
688
689 /* Must not reply to returned packets */
690 if (cb->rt_flags & DN_RT_F_RTS)
691 goto out;
692
693 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
694 switch(cb->nsp_flags & 0x70) {
695 case 0x10:
696 case 0x60: /* (Retransmitted) Connect Init */
697 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
698 ret = NET_RX_SUCCESS;
699 break;
700 case 0x20: /* Connect Confirm */
701 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
702 ret = NET_RX_SUCCESS;
703 break;
704 }
705 }
706
707out:
708 kfree_skb(skb);
709 return ret;
710}
711
712static int dn_nsp_rx_packet(struct sk_buff *skb)
713{
714 struct dn_skb_cb *cb = DN_SKB_CB(skb);
715 struct sock *sk = NULL;
716 unsigned char *ptr = (unsigned char *)skb->data;
717 unsigned short reason = NSP_REASON_NL;
718
719 if (!pskb_may_pull(skb, 2))
720 goto free_out;
721
badff6d0 722 skb_reset_transport_header(skb);
1da177e4
LT		 723 cb->nsp_flags = *ptr++;
724
725 if (decnet_debug_level & 2)
726 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
727
429eb0fa 728 if (cb->nsp_flags & 0x83)
1da177e4
LT		 729 goto free_out;
730
731 /*
732 * Filter out conninits and useless packet types
733 */
734 if ((cb->nsp_flags & 0x0c) == 0x08) {
735 switch(cb->nsp_flags & 0x70) {
736 case 0x00: /* NOP */
737 case 0x70: /* Reserved */
738 case 0x50: /* Reserved, Phase II node init */
739 goto free_out;
740 case 0x10:
741 case 0x60:
742 if (unlikely(cb->rt_flags & DN_RT_F_RTS))
743 goto free_out;
744 sk = dn_find_listener(skb, &reason);
745 goto got_it;
746 }
747 }
748
749 if (!pskb_may_pull(skb, 3))
750 goto free_out;
751
752 /*
753 * Grab the destination address.
754 */
c4ea94ab 755 cb->dst_port = *(__le16 *)ptr;
1da177e4
LT		 756 cb->src_port = 0;
757 ptr += 2;
758
759 /*
760 * If not a connack, grab the source address too.
761 */
762 if (pskb_may_pull(skb, 5)) {
c4ea94ab 763 cb->src_port = *(__le16 *)ptr;
1da177e4
LT		 764 ptr += 2;
765 skb_pull(skb, 5);
766 }
767
768 /*
769 * Returned packets...
770 * Swap src & dst and look up in the normal way.
771 */
772 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
c4ea94ab 773 __le16 tmp = cb->dst_port;
1da177e4
LT		 774 cb->dst_port = cb->src_port;
775 cb->src_port = tmp;
776 tmp = cb->dst;
777 cb->dst = cb->src;
778 cb->src = tmp;
779 }
780
781 /*
782 * Find the socket to which this skb is destined.
783 */
784 sk = dn_find_by_skb(skb);
785got_it:
786 if (sk != NULL) {
787 struct dn_scp *scp = DN_SK(sk);
1da177e4
LT		 788
789 /* Reset backoff */
790 scp->nsp_rxtshift = 0;
791
792 /*
793 * We linearize everything except data segments here.
794 */
795 if (cb->nsp_flags & ~0x60) {
364c6bad 796 if (unlikely(skb_linearize(skb)))
1da177e4
LT		 797 goto free_out;
798 }
799
58a5a7b9 800 return sk_receive_skb(sk, skb, 0);
1da177e4
LT		 801 }
802
803 return dn_nsp_no_socket(skb, reason);
804
805free_out:
806 kfree_skb(skb);
807 return NET_RX_DROP;
808}
809
810int dn_nsp_rx(struct sk_buff *skb)
811{
812 return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
813}
814
815/*
816 * This is the main receive routine for sockets. It is called
817 * from the above when the socket is not busy, and also from
818 * sock_release() when there is a backlog queued up.
819 */
820int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
821{
822 struct dn_scp *scp = DN_SK(sk);
823 struct dn_skb_cb *cb = DN_SKB_CB(skb);
824
825 if (cb->rt_flags & DN_RT_F_RTS) {
826 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
827 dn_returned_conn_init(sk, skb);
828 else
829 kfree_skb(skb);
830 return NET_RX_SUCCESS;
831 }
832
833 /*
834 * Control packet.
835 */
836 if ((cb->nsp_flags & 0x0c) == 0x08) {
837 switch(cb->nsp_flags & 0x70) {
838 case 0x10:
839 case 0x60:
840 dn_nsp_conn_init(sk, skb);
841 break;
842 case 0x20:
843 dn_nsp_conn_conf(sk, skb);
844 break;
845 case 0x30:
846 dn_nsp_disc_init(sk, skb);
847 break;
429eb0fa 848 case 0x40:
1da177e4
LT		 849 dn_nsp_disc_conf(sk, skb);
850 break;
851 }
852
853 } else if (cb->nsp_flags == 0x24) {
854 /*
855 * Special for connacks, 'cos they don't have
856 * ack data or ack otherdata info.
857 */
858 dn_nsp_conn_ack(sk, skb);
859 } else {
860 int other = 1;
861
862 /* both data and ack frames can kick a CC socket into RUN */
863 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
864 scp->state = DN_RUN;
865 sk->sk_state = TCP_ESTABLISHED;
866 sk->sk_state_change(sk);
867 }
868
869 if ((cb->nsp_flags & 0x1c) == 0)
870 other = 0;
871 if (cb->nsp_flags == 0x04)
872 other = 0;
873
874 /*
875 * Read out ack data here, this applies equally
876 * to data, other data, link serivce and both
877 * ack data and ack otherdata.
878 */
879 dn_process_ack(sk, skb, other);
880
881 /*
882 * If we've some sort of data here then call a
883 * suitable routine for dealing with it, otherwise
884 * the packet is an ack and can be discarded.
885 */
886 if ((cb->nsp_flags & 0x0c) == 0) {
887
888 if (scp->state != DN_RUN)
889 goto free_out;
890
891 switch(cb->nsp_flags) {
892 case 0x10: /* LS */
893 dn_nsp_linkservice(sk, skb);
894 break;
895 case 0x30: /* OD */
896 dn_nsp_otherdata(sk, skb);
897 break;
898 default:
899 dn_nsp_data(sk, skb);
900 }
901
902 } else { /* Ack, chuck it out here */
903free_out:
904 kfree_skb(skb);
905 }
906 }
907
908 return NET_RX_SUCCESS;
909}
910
Linux 6.x block layer and io_uring tree(s)