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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [decnet/] [dn_nsp_in.c] - Blame information for rev 1765

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Line No. Rev Author Line
1 1275 phoenix
/*
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
 */
32
 
33
/******************************************************************************
34
    (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
35
 
36
    This program is free software; you can redistribute it and/or modify
37
    it under the terms of the GNU General Public License as published by
38
    the Free Software Foundation; either version 2 of the License, or
39
    any later version.
40
 
41
    This program is distributed in the hope that it will be useful,
42
    but WITHOUT ANY WARRANTY; without even the implied warranty of
43
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
44
    GNU General Public License for more details.
45
*******************************************************************************/
46
 
47
#include <linux/config.h>
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/sched.h>
54
#include <linux/timer.h>
55
#include <linux/string.h>
56
#include <linux/sockios.h>
57
#include <linux/net.h>
58
#include <linux/netdevice.h>
59
#include <linux/inet.h>
60
#include <linux/route.h>
61
#include <net/sock.h>
62
#include <asm/segment.h>
63
#include <asm/system.h>
64
#include <linux/fcntl.h>
65
#include <linux/mm.h>
66
#include <linux/termios.h>      
67
#include <linux/interrupt.h>
68
#include <linux/proc_fs.h>
69
#include <linux/stat.h>
70
#include <linux/init.h>
71
#include <linux/poll.h>
72
#include <linux/netfilter_decnet.h>
73
#include <net/neighbour.h>
74
#include <net/dst.h>
75
#include <net/dn_nsp.h>
76
#include <net/dn_dev.h>
77
#include <net/dn_route.h>
78
 
79
extern int decnet_log_martians;
80
 
81
static void dn_log_martian(struct sk_buff *skb, const char *msg)
82
{
83
        if (decnet_log_martians && net_ratelimit()) {
84
                char *devname = skb->dev ? skb->dev->name : "???";
85
                struct dn_skb_cb *cb = DN_SKB_CB(skb);
86
                printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n", msg, devname, cb->src, cb->dst, cb->src_port, cb->dst_port);
87
        }
88
}
89
 
90
/*
91
 * For this function we've flipped the cross-subchannel bit
92
 * if the message is an otherdata or linkservice message. Thus
93
 * we can use it to work out what to update.
94
 */
95
static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
96
{
97
        struct dn_scp *scp = DN_SK(sk);
98
        unsigned short type = ((ack >> 12) & 0x0003);
99
        int wakeup = 0;
100
 
101
        switch(type) {
102
                case 0: /* ACK - Data */
103
                        if (after(ack, scp->ackrcv_dat)) {
104
                                scp->ackrcv_dat = ack & 0x0fff;
105
                                wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
106
                        }
107
                        break;
108
                case 1: /* NAK - Data */
109
                        break;
110
                case 2: /* ACK - OtherData */
111
                        if (after(ack, scp->ackrcv_oth)) {
112
                                scp->ackrcv_oth = ack & 0x0fff;
113
                                wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
114
                        }
115
                        break;
116
                case 3: /* NAK - OtherData */
117
                        break;
118
        }
119
 
120
        if (wakeup && !sk->dead)
121
                sk->state_change(sk);
122
}
123
 
124
/*
125
 * This function is a universal ack processor.
126
 */
127
static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
128
{
129
        unsigned short *ptr = (unsigned short *)skb->data;
130
        int len = 0;
131
        unsigned short ack;
132
 
133
        if (skb->len < 2)
134
                return len;
135
 
136
        if ((ack = dn_ntohs(*ptr)) & 0x8000) {
137
                skb_pull(skb, 2);
138
                ptr++;
139
                len += 2;
140
                if ((ack & 0x4000) == 0) {
141
                        if (oth)
142
                                ack ^= 0x2000;
143
                        dn_ack(sk, skb, ack);
144
                }
145
        }
146
 
147
        if (skb->len < 2)
148
                return len;
149
 
150
        if ((ack = dn_ntohs(*ptr)) & 0x8000) {
151
                skb_pull(skb, 2);
152
                len += 2;
153
                if ((ack & 0x4000) == 0) {
154
                        if (oth)
155
                                ack ^= 0x2000;
156
                        dn_ack(sk, skb, ack);
157
                }
158
        }
159
 
160
        return len;
161
}
162
 
163
 
164
/**
165
 * dn_check_idf - Check an image data field format is correct.
166
 * @pptr: Pointer to pointer to image data
167
 * @len: Pointer to length of image data
168
 * @max: The maximum allowed length of the data in the image data field
169
 * @follow_on: Check that this many bytes exist beyond the end of the image data
170
 *
171
 * Returns: 0 if ok, -1 on error
172
 */
173
static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
174
{
175
        unsigned char *ptr = *pptr;
176
        unsigned char flen = *ptr++;
177
 
178
        (*len)--;
179
        if (flen > max)
180
                return -1;
181
        if ((flen + follow_on) > *len)
182
                return -1;
183
 
184
        *len -= flen;
185
        *pptr = ptr + flen;
186
        return 0;
187
}
188
 
189
/*
190
 * Table of reason codes to pass back to node which sent us a badly
191
 * formed message, plus text messages for the log. A zero entry in
192
 * the reason field means "don't reply" otherwise a disc init is sent with
193
 * the specified reason code.
194
 */
195
static struct {
196
        unsigned short reason;
197
        const char *text;
198
} ci_err_table[] = {
199
 { 0,             "CI: Truncated message" },
200
 { NSP_REASON_ID, "CI: Destination username error" },
201
 { NSP_REASON_ID, "CI: Destination username type" },
202
 { NSP_REASON_US, "CI: Source username error" },
203
 { 0,             "CI: Truncated at menuver" },
204
 { 0,             "CI: Truncated before access or user data" },
205
 { NSP_REASON_IO, "CI: Access data format error" },
206
 { NSP_REASON_IO, "CI: User data format error" }
207
};
208
 
209
/*
210
 * This function uses a slightly different lookup method
211
 * to find its sockets, since it searches on object name/number
212
 * rather than port numbers. Various tests are done to ensure that
213
 * the incoming data is in the correct format before it is queued to
214
 * a socket.
215
 */
216
static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
217
{
218
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
219
        struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
220
        struct sockaddr_dn dstaddr;
221
        struct sockaddr_dn srcaddr;
222
        unsigned char type = 0;
223
        int dstlen;
224
        int srclen;
225
        unsigned char *ptr;
226
        int len;
227
        int err = 0;
228
        unsigned char menuver;
229
 
230
        memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
231
        memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
232
 
233
        /*
234
         * 1. Decode & remove message header
235
         */
236
        cb->src_port = msg->srcaddr;
237
        cb->dst_port = msg->dstaddr;
238
        cb->services = msg->services;
239
        cb->info     = msg->info;
240
        cb->segsize  = dn_ntohs(msg->segsize);
241
 
242
        if (skb->len < sizeof(*msg))
243
                goto err_out;
244
 
245
        skb_pull(skb, sizeof(*msg));
246
 
247
        len = skb->len;
248
        ptr = skb->data;
249
 
250
        /*
251
         * 2. Check destination end username format
252
         */
253
        dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
254
        err++;
255
        if (dstlen < 0)
256
                goto err_out;
257
 
258
        err++;
259
        if (type > 1)
260
                goto err_out;
261
 
262
        len -= dstlen;
263
        ptr += dstlen;
264
 
265
        /*
266
         * 3. Check source end username format
267
         */
268
        srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
269
        err++;
270
        if (srclen < 0)
271
                goto err_out;
272
 
273
        len -= srclen;
274
        ptr += srclen;
275
        err++;
276
        if (len < 1)
277
                goto err_out;
278
 
279
        menuver = *ptr;
280
        ptr++;
281
        len--;
282
 
283
        /*
284
         * 4. Check that optional data actually exists if menuver says it does
285
         */
286
        err++;
287
        if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
288
                goto err_out;
289
 
290
        /*
291
         * 5. Check optional access data format
292
         */
293
        err++;
294
        if (menuver & DN_MENUVER_ACC) {
295
                if (dn_check_idf(&ptr, &len, 39, 1))
296
                        goto err_out;
297
                if (dn_check_idf(&ptr, &len, 39, 1))
298
                        goto err_out;
299
                if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
300
                        goto err_out;
301
        }
302
 
303
        /*
304
         * 6. Check optional user data format
305
         */
306
        err++;
307
        if (menuver & DN_MENUVER_USR) {
308
                if (dn_check_idf(&ptr, &len, 16, 0))
309
                        goto err_out;
310
        }
311
 
312
        /*
313
         * 7. Look up socket based on destination end username
314
         */
315
        return dn_sklist_find_listener(&dstaddr);
316
err_out:
317
        dn_log_martian(skb, ci_err_table[err].text);
318
        *reason = ci_err_table[err].reason;
319
        return NULL;
320
}
321
 
322
 
323
static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
324
{
325
        if (sk->ack_backlog >= sk->max_ack_backlog) {
326
                kfree_skb(skb);
327
                return;
328
        }
329
 
330
        sk->ack_backlog++;
331
        skb_queue_tail(&sk->receive_queue, skb);
332
        sk->state_change(sk);
333
}
334
 
335
static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
336
{
337
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
338
        struct dn_scp *scp = DN_SK(sk);
339
        unsigned char *ptr;
340
 
341
        if (skb->len < 4)
342
                goto out;
343
 
344
        ptr = skb->data;
345
        cb->services = *ptr++;
346
        cb->info = *ptr++;
347
        cb->segsize = dn_ntohs(*(__u16 *)ptr);
348
 
349
        if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
350
                scp->persist = 0;
351
                scp->addrrem = cb->src_port;
352
                sk->state = TCP_ESTABLISHED;
353
                scp->state = DN_RUN;
354
                scp->services_rem = cb->services;
355
                scp->info_rem = cb->info;
356
                scp->segsize_rem = cb->segsize;
357
 
358
                if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
359
                        scp->max_window = decnet_no_fc_max_cwnd;
360
 
361
                if (skb->len > 0) {
362
                        unsigned char dlen = *skb->data;
363
                        if ((dlen <= 16) && (dlen <= skb->len)) {
364
                                scp->conndata_in.opt_optl = dlen;
365
                                memcpy(scp->conndata_in.opt_data, skb->data + 1, dlen);
366
                        }
367
                }
368
                dn_nsp_send_link(sk, DN_NOCHANGE, 0);
369
                if (!sk->dead)
370
                        sk->state_change(sk);
371
        }
372
 
373
out:
374
        kfree_skb(skb);
375
}
376
 
377
static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
378
{
379
        struct dn_scp *scp = DN_SK(sk);
380
 
381
        if (scp->state == DN_CI) {
382
                scp->state = DN_CD;
383
                scp->persist = 0;
384
        }
385
 
386
        kfree_skb(skb);
387
}
388
 
389
static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
390
{
391
        struct dn_scp *scp = DN_SK(sk);
392
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
393
        unsigned short reason;
394
 
395
        if (skb->len < 2)
396
                goto out;
397
 
398
        reason = dn_ntohs(*(__u16 *)skb->data);
399
        skb_pull(skb, 2);
400
 
401
        scp->discdata_in.opt_status = reason;
402
        scp->discdata_in.opt_optl   = 0;
403
        memset(scp->discdata_in.opt_data, 0, 16);
404
 
405
        if (skb->len > 0) {
406
                unsigned char dlen = *skb->data;
407
                if ((dlen <= 16) && (dlen <= skb->len)) {
408
                        scp->discdata_in.opt_optl = dlen;
409
                        memcpy(scp->discdata_in.opt_data, skb->data + 1, dlen);
410
                }
411
        }
412
 
413
        scp->addrrem = cb->src_port;
414
        sk->state    = TCP_CLOSE;
415
 
416
        switch(scp->state) {
417
                case DN_CI:
418
                case DN_CD:
419
                        scp->state = DN_RJ;
420
                        break;
421
                case DN_RUN:
422
                        sk->shutdown |= SHUTDOWN_MASK;
423
                        scp->state = DN_DN;
424
                        break;
425
                case DN_DI:
426
                        scp->state = DN_DIC;
427
                        break;
428
        }
429
 
430
        if (!sk->dead) {
431
                if (sk->socket->state != SS_UNCONNECTED)
432
                        sk->socket->state = SS_DISCONNECTING;
433
                sk->state_change(sk);
434
        }
435
 
436
        dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
437
        scp->persist_fxn = dn_destroy_timer;
438
        scp->persist = dn_nsp_persist(sk);
439
 
440
out:
441
        kfree_skb(skb);
442
}
443
 
444
/*
445
 * disc_conf messages are also called no_resources or no_link
446
 * messages depending upon the "reason" field.
447
 */
448
static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
449
{
450
        struct dn_scp *scp = DN_SK(sk);
451
        unsigned short reason;
452
 
453
        if (skb->len != 2)
454
                goto out;
455
 
456
        reason = dn_ntohs(*(__u16 *)skb->data);
457
 
458
        sk->state = TCP_CLOSE;
459
 
460
        switch(scp->state) {
461
                case DN_CI:
462
                        scp->state = DN_NR;
463
                        break;
464
                case DN_DR:
465
                        if (reason == NSP_REASON_DC)
466
                                scp->state = DN_DRC;
467
                        if (reason == NSP_REASON_NL)
468
                                scp->state = DN_CN;
469
                        break;
470
                case DN_DI:
471
                        scp->state = DN_DIC;
472
                        break;
473
                case DN_RUN:
474
                        sk->shutdown |= SHUTDOWN_MASK;
475
                case DN_CC:
476
                        scp->state = DN_CN;
477
        }
478
 
479
        if (!sk->dead) {
480
                if (sk->socket->state != SS_UNCONNECTED)
481
                        sk->socket->state = SS_DISCONNECTING;
482
                sk->state_change(sk);
483
        }
484
 
485
        scp->persist_fxn = dn_destroy_timer;
486
        scp->persist = dn_nsp_persist(sk);
487
 
488
out:
489
        kfree_skb(skb);
490
}
491
 
492
static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
493
{
494
        struct dn_scp *scp = DN_SK(sk);
495
        unsigned short segnum;
496
        unsigned char lsflags;
497
        char fcval;
498
        int wake_up = 0;
499
        char *ptr = skb->data;
500
        unsigned char fctype = scp->services_rem & NSP_FC_MASK;
501
 
502
        if (skb->len != 4)
503
                goto out;
504
 
505
        segnum = dn_ntohs(*(__u16 *)ptr);
506
        ptr += 2;
507
        lsflags = *(unsigned char *)ptr++;
508
        fcval = *ptr;
509
 
510
        /*
511
         * Here we ignore erronous packets which should really
512
         * should cause a connection abort. It is not critical
513
         * for now though.
514
         */
515
        if (lsflags & 0xf8)
516
                goto out;
517
 
518
        if (seq_next(scp->numoth_rcv, segnum)) {
519
                seq_add(&scp->numoth_rcv, 1);
520
                switch(lsflags & 0x04) { /* FCVAL INT */
521
                case 0x00: /* Normal Request */
522
                        switch(lsflags & 0x03) { /* FCVAL MOD */
523
                        case 0x00: /* Request count */
524
                                if (fcval < 0) {
525
                                        unsigned char p_fcval = -fcval;
526
                                        if ((scp->flowrem_dat > p_fcval) &&
527
                                            (fctype == NSP_FC_SCMC)) {
528
                                                scp->flowrem_dat -= p_fcval;
529
                                        }
530
                                } else if (fcval > 0) {
531
                                        scp->flowrem_dat += fcval;
532
                                        wake_up = 1;
533
                                }
534
                                break;
535
                        case 0x01: /* Stop outgoing data */
536
                                scp->flowrem_sw = DN_DONTSEND;
537
                                break;
538
                        case 0x02: /* Ok to start again */
539
                                scp->flowrem_sw = DN_SEND;
540
                                dn_nsp_output(sk);
541
                                wake_up = 1;
542
                        }
543
                        break;
544
                case 0x04: /* Interrupt Request */
545
                        if (fcval > 0) {
546
                                scp->flowrem_oth += fcval;
547
                                wake_up = 1;
548
                        }
549
                        break;
550
                }
551
                if (wake_up && !sk->dead)
552
                        sk->state_change(sk);
553
        }
554
 
555
        dn_nsp_send_oth_ack(sk);
556
 
557
out:
558
        kfree_skb(skb);
559
}
560
 
561
/*
562
 * Copy of sock_queue_rcv_skb (from sock.h) without
563
 * bh_lock_sock() (its already held when this is called) which
564
 * also allows data and other data to be queued to a socket.
565
 */
566
static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
567
{
568
        int err;
569
 
570
        /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
571
           number of warnings when compiling with -W --ANK
572
         */
573
        if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf) {
574
                err = -ENOMEM;
575
                goto out;
576
        }
577
 
578
        err = sk_filter(sk, skb, 0);
579
        if (err)
580
                goto out;
581
 
582
        skb_set_owner_r(skb, sk);
583
        skb_queue_tail(queue, skb);
584
 
585
        /* This code only runs from BH or BH protected context.
586
         * Therefore the plain read_lock is ok here. -DaveM
587
         */
588
        read_lock(&sk->callback_lock);
589
        if (!sk->dead) {
590
                struct socket *sock = sk->socket;
591
                wake_up_interruptible(sk->sleep);
592
                if (sock && sock->fasync_list &&
593
                    !test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
594
                        __kill_fasync(sock->fasync_list, sig,
595
                                    (sig == SIGURG) ? POLL_PRI : POLL_IN);
596
        }
597
        read_unlock(&sk->callback_lock);
598
out:
599
        return err;
600
}
601
 
602
static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
603
{
604
        struct dn_scp *scp = DN_SK(sk);
605
        unsigned short segnum;
606
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
607
        int queued = 0;
608
 
609
        if (skb->len < 2)
610
                goto out;
611
 
612
        cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
613
        skb_pull(skb, 2);
614
 
615
        if (seq_next(scp->numoth_rcv, segnum)) {
616
 
617
                if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
618
                        seq_add(&scp->numoth_rcv, 1);
619
                        scp->other_report = 0;
620
                        queued = 1;
621
                }
622
        }
623
 
624
        dn_nsp_send_oth_ack(sk);
625
out:
626
        if (!queued)
627
                kfree_skb(skb);
628
}
629
 
630
static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
631
{
632
        int queued = 0;
633
        unsigned short segnum;
634
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
635
        struct dn_scp *scp = DN_SK(sk);
636
 
637
        if (skb->len < 2)
638
                goto out;
639
 
640
        cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
641
        skb_pull(skb, 2);
642
 
643
        if (seq_next(scp->numdat_rcv, segnum)) {
644
                if (dn_queue_skb(sk, skb, SIGIO, &sk->receive_queue) == 0) {
645
                        seq_add(&scp->numdat_rcv, 1);
646
                        queued = 1;
647
                }
648
 
649
                if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
650
                        scp->flowloc_sw = DN_DONTSEND;
651
                        dn_nsp_send_link(sk, DN_DONTSEND, 0);
652
                }
653
        }
654
 
655
        dn_nsp_send_data_ack(sk);
656
out:
657
        if (!queued)
658
                kfree_skb(skb);
659
}
660
 
661
/*
662
 * If one of our conninit messages is returned, this function
663
 * deals with it. It puts the socket into the NO_COMMUNICATION
664
 * state.
665
 */
666
static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
667
{
668
        struct dn_scp *scp = DN_SK(sk);
669
 
670
        if (scp->state == DN_CI) {
671
                scp->state = DN_NC;
672
                sk->state = TCP_CLOSE;
673
                if (!sk->dead)
674
                        sk->state_change(sk);
675
        }
676
 
677
        kfree_skb(skb);
678
}
679
 
680
static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
681
{
682
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
683
        int ret = NET_RX_DROP;
684
 
685
        /* Must not reply to returned packets */
686
        if (cb->rt_flags & DN_RT_F_RTS)
687
                goto out;
688
 
689
        if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
690
                switch(cb->nsp_flags & 0x70) {
691
                        case 0x10:
692
                        case 0x60: /* (Retransmitted) Connect Init */
693
                                dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
694
                                ret = NET_RX_SUCCESS;
695
                                break;
696
                        case 0x20: /* Connect Confirm */
697
                                dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
698
                                ret = NET_RX_SUCCESS;
699
                                break;
700
                }
701
        }
702
 
703
out:
704
        kfree_skb(skb);
705
        return ret;
706
}
707
 
708
static int dn_nsp_rx_packet(struct sk_buff *skb)
709
{
710
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
711
        struct sock *sk = NULL;
712
        unsigned char *ptr = (unsigned char *)skb->data;
713
        unsigned short reason = NSP_REASON_NL;
714
 
715
        skb->h.raw    = skb->data;
716
        cb->nsp_flags = *ptr++;
717
 
718
        if (decnet_debug_level & 2)
719
                printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
720
 
721
        if (skb->len < 2)
722
                goto free_out;
723
 
724
        if (cb->nsp_flags & 0x83)
725
                goto free_out;
726
 
727
        /*
728
         * Returned packets...
729
         * Swap src & dst and look up in the normal way.
730
         */
731
        if (cb->rt_flags & DN_RT_F_RTS) {
732
                unsigned short tmp = cb->dst_port;
733
                cb->dst_port = cb->src_port;
734
                cb->src_port = tmp;
735
                tmp = cb->dst;
736
                cb->dst = cb->src;
737
                cb->src = tmp;
738
                sk = dn_find_by_skb(skb);
739
                goto got_it;
740
        }
741
 
742
        /*
743
         * Filter out conninits and useless packet types
744
         */
745
        if ((cb->nsp_flags & 0x0c) == 0x08) {
746
                switch(cb->nsp_flags & 0x70) {
747
                        case 0x00: /* NOP */
748
                        case 0x70: /* Reserved */
749
                        case 0x50: /* Reserved, Phase II node init */
750
                                goto free_out;
751
                        case 0x10:
752
                        case 0x60:
753
                                sk = dn_find_listener(skb, &reason);
754
                                goto got_it;
755
                }
756
        }
757
 
758
        if (skb->len < 3)
759
                goto free_out;
760
 
761
        /*
762
         * Grab the destination address.
763
         */
764
        cb->dst_port = *(unsigned short *)ptr;
765
        cb->src_port = 0;
766
        ptr += 2;
767
 
768
        /*
769
         * If not a connack, grab the source address too.
770
         */
771
        if (skb->len >= 5) {
772
                cb->src_port = *(unsigned short *)ptr;
773
                ptr += 2;
774
                skb_pull(skb, 5);
775
        }
776
 
777
        /*
778
         * Find the socket to which this skb is destined.
779
         */
780
        sk = dn_find_by_skb(skb);
781
got_it:
782
        if (sk != NULL) {
783
                struct dn_scp *scp = DN_SK(sk);
784
                int ret;
785
 
786
                /* Reset backoff */
787
                scp->nsp_rxtshift = 0;
788
 
789
                bh_lock_sock(sk);
790
                ret = NET_RX_SUCCESS;
791
                if (decnet_debug_level & 8)
792
                        printk(KERN_DEBUG "NSP: 0x%02x 0x%02x 0x%04x 0x%04x %d\n",
793
                                (int)cb->rt_flags, (int)cb->nsp_flags,
794
                                (int)cb->src_port, (int)cb->dst_port,
795
                                (int)sk->lock.users);
796
                if (sk->lock.users == 0)
797
                        ret = dn_nsp_backlog_rcv(sk, skb);
798
                else
799
                        sk_add_backlog(sk, skb);
800
                bh_unlock_sock(sk);
801
                sock_put(sk);
802
 
803
                return ret;
804
        }
805
 
806
        return dn_nsp_no_socket(skb, reason);
807
 
808
free_out:
809
        kfree_skb(skb);
810
        return NET_RX_DROP;
811
}
812
 
813
int dn_nsp_rx(struct sk_buff *skb)
814
{
815
        return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
816
}
817
 
818
/*
819
 * This is the main receive routine for sockets. It is called
820
 * from the above when the socket is not busy, and also from
821
 * sock_release() when there is a backlog queued up.
822
 */
823
int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
824
{
825
        struct dn_scp *scp = DN_SK(sk);
826
        struct dn_skb_cb *cb = DN_SKB_CB(skb);
827
 
828
        if (cb->rt_flags & DN_RT_F_RTS) {
829
                dn_returned_conn_init(sk, 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;
848
                        case 0x40:
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) && !sk->dead) {
864
                        scp->state = DN_RUN;
865
                        sk->state = TCP_ESTABLISHED;
866
                        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 */
903
free_out:
904
                        kfree_skb(skb);
905
                }
906
        }
907
 
908
        return NET_RX_SUCCESS;
909
}
910
 

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