dn_nsp_in.c 21.0 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
/*
 * DECnet       An implementation of the DECnet protocol suite for the LINUX
 *              operating system.  DECnet is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              DECnet Network Services Protocol (Input)
 *
 * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>
 *
 * Changes:
 *
 *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from
 *                       original dn_nsp.c.
 *    Steve Whitehouse:  Updated to work with my new routing architecture.
 *    Steve Whitehouse:  Add changes from Eduardo Serrat's patches.
 *    Steve Whitehouse:  Put all ack handling code in a common routine.
 *    Steve Whitehouse:  Put other common bits into dn_nsp_rx()
 *    Steve Whitehouse:  More checks on skb->len to catch bogus packets
 *                       Fixed various race conditions and possible nasties.
 *    Steve Whitehouse:  Now handles returned conninit frames.
 *     David S. Miller:  New socket locking
 *    Steve Whitehouse:  Fixed lockup when socket filtering was enabled.
 *         Paul Koning:  Fix to push CC sockets into RUN when acks are
 *                       received.
 *    Steve Whitehouse:
 *   Patrick Caulfield:  Checking conninits for correctness & sending of error
 *                       responses.
 *    Steve Whitehouse:  Added backlog congestion level return codes.
 *   Patrick Caulfield:
 *    Steve Whitehouse:  Added flow control support (outbound)
 *    Steve Whitehouse:  Prepare for nonlinear skbs
 */

/******************************************************************************
    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
36

L
Linus Torvalds 已提交
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*******************************************************************************/

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/inet.h>
#include <linux/route.h>
60
#include <linux/slab.h>
L
Linus Torvalds 已提交
61
#include <net/sock.h>
62
#include <net/tcp_states.h>
L
Linus Torvalds 已提交
63 64
#include <linux/fcntl.h>
#include <linux/mm.h>
65
#include <linux/termios.h>
L
Linus Torvalds 已提交
66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/netfilter_decnet.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/dn.h>
#include <net/dn_nsp.h>
#include <net/dn_dev.h>
#include <net/dn_route.h>

extern int decnet_log_martians;

static void dn_log_martian(struct sk_buff *skb, const char *msg)
{
83
	if (decnet_log_martians) {
L
Linus Torvalds 已提交
84 85
		char *devname = skb->dev ? skb->dev->name : "???";
		struct dn_skb_cb *cb = DN_SKB_CB(skb);
86 87 88 89 90 91
		net_info_ratelimited("DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
				     msg, devname,
				     le16_to_cpu(cb->src),
				     le16_to_cpu(cb->dst),
				     le16_to_cpu(cb->src_port),
				     le16_to_cpu(cb->dst_port));
L
Linus Torvalds 已提交
92 93 94 95 96 97 98 99 100 101 102 103 104 105
	}
}

/*
 * For this function we've flipped the cross-subchannel bit
 * if the message is an otherdata or linkservice message. Thus
 * we can use it to work out what to update.
 */
static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
{
	struct dn_scp *scp = DN_SK(sk);
	unsigned short type = ((ack >> 12) & 0x0003);
	int wakeup = 0;

J
Joe Perches 已提交
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126
	switch (type) {
	case 0: /* ACK - Data */
		if (dn_after(ack, scp->ackrcv_dat)) {
			scp->ackrcv_dat = ack & 0x0fff;
			wakeup |= dn_nsp_check_xmit_queue(sk, skb,
							  &scp->data_xmit_queue,
							  ack);
		}
		break;
	case 1: /* NAK - Data */
		break;
	case 2: /* ACK - OtherData */
		if (dn_after(ack, scp->ackrcv_oth)) {
			scp->ackrcv_oth = ack & 0x0fff;
			wakeup |= dn_nsp_check_xmit_queue(sk, skb,
							  &scp->other_xmit_queue,
							  ack);
		}
		break;
	case 3: /* NAK - OtherData */
		break;
L
Linus Torvalds 已提交
127 128 129 130 131 132 133 134 135 136 137
	}

	if (wakeup && !sock_flag(sk, SOCK_DEAD))
		sk->sk_state_change(sk);
}

/*
 * This function is a universal ack processor.
 */
static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
{
138
	__le16 *ptr = (__le16 *)skb->data;
L
Linus Torvalds 已提交
139 140 141 142 143 144
	int len = 0;
	unsigned short ack;

	if (skb->len < 2)
		return len;

145
	if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
L
Linus Torvalds 已提交
146 147 148 149
		skb_pull(skb, 2);
		ptr++;
		len += 2;
		if ((ack & 0x4000) == 0) {
150
			if (oth)
L
Linus Torvalds 已提交
151 152 153 154 155 156 157 158
				ack ^= 0x2000;
			dn_ack(sk, skb, ack);
		}
	}

	if (skb->len < 2)
		return len;

159
	if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
L
Linus Torvalds 已提交
160 161 162
		skb_pull(skb, 2);
		len += 2;
		if ((ack & 0x4000) == 0) {
163
			if (oth)
L
Linus Torvalds 已提交
164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248
				ack ^= 0x2000;
			dn_ack(sk, skb, ack);
		}
	}

	return len;
}


/**
 * dn_check_idf - Check an image data field format is correct.
 * @pptr: Pointer to pointer to image data
 * @len: Pointer to length of image data
 * @max: The maximum allowed length of the data in the image data field
 * @follow_on: Check that this many bytes exist beyond the end of the image data
 *
 * Returns: 0 if ok, -1 on error
 */
static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
{
	unsigned char *ptr = *pptr;
	unsigned char flen = *ptr++;

	(*len)--;
	if (flen > max)
		return -1;
	if ((flen + follow_on) > *len)
		return -1;

	*len -= flen;
	*pptr = ptr + flen;
	return 0;
}

/*
 * Table of reason codes to pass back to node which sent us a badly
 * formed message, plus text messages for the log. A zero entry in
 * the reason field means "don't reply" otherwise a disc init is sent with
 * the specified reason code.
 */
static struct {
	unsigned short reason;
	const char *text;
} ci_err_table[] = {
 { 0,             "CI: Truncated message" },
 { NSP_REASON_ID, "CI: Destination username error" },
 { NSP_REASON_ID, "CI: Destination username type" },
 { NSP_REASON_US, "CI: Source username error" },
 { 0,             "CI: Truncated at menuver" },
 { 0,             "CI: Truncated before access or user data" },
 { NSP_REASON_IO, "CI: Access data format error" },
 { NSP_REASON_IO, "CI: User data format error" }
};

/*
 * This function uses a slightly different lookup method
 * to find its sockets, since it searches on object name/number
 * rather than port numbers. Various tests are done to ensure that
 * the incoming data is in the correct format before it is queued to
 * a socket.
 */
static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
{
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
	struct sockaddr_dn dstaddr;
	struct sockaddr_dn srcaddr;
	unsigned char type = 0;
	int dstlen;
	int srclen;
	unsigned char *ptr;
	int len;
	int err = 0;
	unsigned char menuver;

	memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
	memset(&srcaddr, 0, sizeof(struct sockaddr_dn));

	/*
	 * 1. Decode & remove message header
	 */
	cb->src_port = msg->srcaddr;
	cb->dst_port = msg->dstaddr;
	cb->services = msg->services;
	cb->info     = msg->info;
249
	cb->segsize  = le16_to_cpu(msg->segsize);
L
Linus Torvalds 已提交
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355

	if (!pskb_may_pull(skb, sizeof(*msg)))
		goto err_out;

	skb_pull(skb, sizeof(*msg));

	len = skb->len;
	ptr = skb->data;

	/*
	 * 2. Check destination end username format
	 */
	dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
	err++;
	if (dstlen < 0)
		goto err_out;

	err++;
	if (type > 1)
		goto err_out;

	len -= dstlen;
	ptr += dstlen;

	/*
	 * 3. Check source end username format
	 */
	srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
	err++;
	if (srclen < 0)
		goto err_out;

	len -= srclen;
	ptr += srclen;
	err++;
	if (len < 1)
		goto err_out;

	menuver = *ptr;
	ptr++;
	len--;

	/*
	 * 4. Check that optional data actually exists if menuver says it does
	 */
	err++;
	if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
		goto err_out;

	/*
	 * 5. Check optional access data format
	 */
	err++;
	if (menuver & DN_MENUVER_ACC) {
		if (dn_check_idf(&ptr, &len, 39, 1))
			goto err_out;
		if (dn_check_idf(&ptr, &len, 39, 1))
			goto err_out;
		if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
			goto err_out;
	}

	/*
	 * 6. Check optional user data format
	 */
	err++;
	if (menuver & DN_MENUVER_USR) {
		if (dn_check_idf(&ptr, &len, 16, 0))
			goto err_out;
	}

	/*
	 * 7. Look up socket based on destination end username
	 */
	return dn_sklist_find_listener(&dstaddr);
err_out:
	dn_log_martian(skb, ci_err_table[err].text);
	*reason = ci_err_table[err].reason;
	return NULL;
}


static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
{
	if (sk_acceptq_is_full(sk)) {
		kfree_skb(skb);
		return;
	}

	sk->sk_ack_backlog++;
	skb_queue_tail(&sk->sk_receive_queue, skb);
	sk->sk_state_change(sk);
}

static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
{
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	struct dn_scp *scp = DN_SK(sk);
	unsigned char *ptr;

	if (skb->len < 4)
		goto out;

	ptr = skb->data;
	cb->services = *ptr++;
	cb->info = *ptr++;
356
	cb->segsize = le16_to_cpu(*(__le16 *)ptr);
L
Linus Torvalds 已提交
357 358 359

	if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
		scp->persist = 0;
360 361 362
		scp->addrrem = cb->src_port;
		sk->sk_state = TCP_ESTABLISHED;
		scp->state = DN_RUN;
L
Linus Torvalds 已提交
363 364 365 366 367 368 369 370
		scp->services_rem = cb->services;
		scp->info_rem = cb->info;
		scp->segsize_rem = cb->segsize;

		if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
			scp->max_window = decnet_no_fc_max_cwnd;

		if (skb->len > 0) {
371
			u16 dlen = *skb->data;
L
Linus Torvalds 已提交
372
			if ((dlen <= 16) && (dlen <= skb->len)) {
373
				scp->conndata_in.opt_optl = cpu_to_le16(dlen);
374 375
				skb_copy_from_linear_data_offset(skb, 1,
					      scp->conndata_in.opt_data, dlen);
L
Linus Torvalds 已提交
376 377
			}
		}
378 379 380 381
		dn_nsp_send_link(sk, DN_NOCHANGE, 0);
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
	}
L
Linus Torvalds 已提交
382 383

out:
384
	kfree_skb(skb);
L
Linus Torvalds 已提交
385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407
}

static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);

	if (scp->state == DN_CI) {
		scp->state = DN_CD;
		scp->persist = 0;
	}

	kfree_skb(skb);
}

static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	unsigned short reason;

	if (skb->len < 2)
		goto out;

408
	reason = le16_to_cpu(*(__le16 *)skb->data);
L
Linus Torvalds 已提交
409 410
	skb_pull(skb, 2);

411
	scp->discdata_in.opt_status = cpu_to_le16(reason);
L
Linus Torvalds 已提交
412 413 414 415
	scp->discdata_in.opt_optl   = 0;
	memset(scp->discdata_in.opt_data, 0, 16);

	if (skb->len > 0) {
416
		u16 dlen = *skb->data;
L
Linus Torvalds 已提交
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);
L
Linus Torvalds 已提交
420 421 422 423 424 425
		}
	}

	scp->addrrem = cb->src_port;
	sk->sk_state = TCP_CLOSE;

J
Joe Perches 已提交
426 427 428 429 430 431 432 433 434 435 436 437 438
	switch (scp->state) {
	case DN_CI:
	case DN_CD:
		scp->state = DN_RJ;
		sk->sk_err = ECONNREFUSED;
		break;
	case DN_RUN:
		sk->sk_shutdown |= SHUTDOWN_MASK;
		scp->state = DN_DN;
		break;
	case DN_DI:
		scp->state = DN_DIC;
		break;
L
Linus Torvalds 已提交
439 440 441 442 443 444 445 446
	}

	if (!sock_flag(sk, SOCK_DEAD)) {
		if (sk->sk_socket->state != SS_UNCONNECTED)
			sk->sk_socket->state = SS_DISCONNECTING;
		sk->sk_state_change(sk);
	}

447
	/*
L
Linus Torvalds 已提交
448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
	 * It appears that its possible for remote machines to send disc
	 * init messages with no port identifier if we are in the CI and
	 * possibly also the CD state. Obviously we shouldn't reply with
	 * a message if we don't know what the end point is.
	 */
	if (scp->addrrem) {
		dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
	}
	scp->persist_fxn = dn_destroy_timer;
	scp->persist = dn_nsp_persist(sk);

out:
	kfree_skb(skb);
}

/*
 * disc_conf messages are also called no_resources or no_link
 * messages depending upon the "reason" field.
 */
static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);
	unsigned short reason;

	if (skb->len != 2)
		goto out;

475
	reason = le16_to_cpu(*(__le16 *)skb->data);
L
Linus Torvalds 已提交
476 477 478

	sk->sk_state = TCP_CLOSE;

J
Joe Perches 已提交
479 480 481 482 483 484 485 486
	switch (scp->state) {
	case DN_CI:
		scp->state = DN_NR;
		break;
	case DN_DR:
		if (reason == NSP_REASON_DC)
			scp->state = DN_DRC;
		if (reason == NSP_REASON_NL)
L
Linus Torvalds 已提交
487
			scp->state = DN_CN;
J
Joe Perches 已提交
488 489 490 491 492 493 494 495
		break;
	case DN_DI:
		scp->state = DN_DIC;
		break;
	case DN_RUN:
		sk->sk_shutdown |= SHUTDOWN_MASK;
	case DN_CC:
		scp->state = DN_CN;
L
Linus Torvalds 已提交
496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523
	}

	if (!sock_flag(sk, SOCK_DEAD)) {
		if (sk->sk_socket->state != SS_UNCONNECTED)
			sk->sk_socket->state = SS_DISCONNECTING;
		sk->sk_state_change(sk);
	}

	scp->persist_fxn = dn_destroy_timer;
	scp->persist = dn_nsp_persist(sk);

out:
	kfree_skb(skb);
}

static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);
	unsigned short segnum;
	unsigned char lsflags;
	signed char fcval;
	int wake_up = 0;
	char *ptr = skb->data;
	unsigned char fctype = scp->services_rem & NSP_FC_MASK;

	if (skb->len != 4)
		goto out;

524
	segnum = le16_to_cpu(*(__le16 *)ptr);
L
Linus Torvalds 已提交
525 526 527 528 529 530
	ptr += 2;
	lsflags = *(unsigned char *)ptr++;
	fcval = *ptr;

	/*
	 * Here we ignore erronous packets which should really
531
	 * should cause a connection abort. It is not critical
L
Linus Torvalds 已提交
532 533 534 535 536 537 538 539 540 541
	 * for now though.
	 */
	if (lsflags & 0xf8)
		goto out;

	if (seq_next(scp->numoth_rcv, segnum)) {
		seq_add(&scp->numoth_rcv, 1);
		switch(lsflags & 0x04) { /* FCVAL INT */
		case 0x00: /* Normal Request */
			switch(lsflags & 0x03) { /* FCVAL MOD */
542
			case 0x00: /* Request count */
L
Linus Torvalds 已提交
543 544 545 546 547 548 549 550 551 552
				if (fcval < 0) {
					unsigned char p_fcval = -fcval;
					if ((scp->flowrem_dat > p_fcval) &&
					    (fctype == NSP_FC_SCMC)) {
						scp->flowrem_dat -= p_fcval;
					}
				} else if (fcval > 0) {
					scp->flowrem_dat += fcval;
					wake_up = 1;
				}
553
				break;
L
Linus Torvalds 已提交
554 555 556 557 558 559 560 561 562 563 564 565 566 567 568
			case 0x01: /* Stop outgoing data */
				scp->flowrem_sw = DN_DONTSEND;
				break;
			case 0x02: /* Ok to start again */
				scp->flowrem_sw = DN_SEND;
				dn_nsp_output(sk);
				wake_up = 1;
			}
			break;
		case 0x04: /* Interrupt Request */
			if (fcval > 0) {
				scp->flowrem_oth += fcval;
				wake_up = 1;
			}
			break;
569
		}
L
Linus Torvalds 已提交
570 571
		if (wake_up && !sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
572
	}
L
Linus Torvalds 已提交
573 574 575 576 577 578 579 580 581 582 583 584 585 586 587

	dn_nsp_send_oth_ack(sk);

out:
	kfree_skb(skb);
}

/*
 * Copy of sock_queue_rcv_skb (from sock.h) without
 * bh_lock_sock() (its already held when this is called) which
 * also allows data and other data to be queued to a socket.
 */
static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
{
	int err;
588 589 590 591 592

	/* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
	   number of warnings when compiling with -W --ANK
	 */
	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
593
	    (unsigned int)sk->sk_rcvbuf) {
594 595 596
		err = -ENOMEM;
		goto out;
	}
L
Linus Torvalds 已提交
597

598
	err = sk_filter(sk, skb);
L
Linus Torvalds 已提交
599 600 601
	if (err)
		goto out;

602 603
	skb_set_owner_r(skb, sk);
	skb_queue_tail(queue, skb);
L
Linus Torvalds 已提交
604

605
	if (!sock_flag(sk, SOCK_DEAD))
606
		sk->sk_data_ready(sk);
L
Linus Torvalds 已提交
607
out:
608
	return err;
L
Linus Torvalds 已提交
609 610 611 612 613 614 615 616 617 618 619 620
}

static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);
	unsigned short segnum;
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	int queued = 0;

	if (skb->len < 2)
		goto out;

621
	cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
L
Linus Torvalds 已提交
622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648
	skb_pull(skb, 2);

	if (seq_next(scp->numoth_rcv, segnum)) {

		if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
			seq_add(&scp->numoth_rcv, 1);
			scp->other_report = 0;
			queued = 1;
		}
	}

	dn_nsp_send_oth_ack(sk);
out:
	if (!queued)
		kfree_skb(skb);
}

static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
{
	int queued = 0;
	unsigned short segnum;
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	struct dn_scp *scp = DN_SK(sk);

	if (skb->len < 2)
		goto out;

649
	cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
L
Linus Torvalds 已提交
650 651 652
	skb_pull(skb, 2);

	if (seq_next(scp->numdat_rcv, segnum)) {
653
		if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
L
Linus Torvalds 已提交
654
			seq_add(&scp->numdat_rcv, 1);
655 656
			queued = 1;
		}
L
Linus Torvalds 已提交
657 658 659 660 661

		if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
			scp->flowloc_sw = DN_DONTSEND;
			dn_nsp_send_link(sk, DN_DONTSEND, 0);
		}
662
	}
L
Linus Torvalds 已提交
663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698

	dn_nsp_send_data_ack(sk);
out:
	if (!queued)
		kfree_skb(skb);
}

/*
 * If one of our conninit messages is returned, this function
 * deals with it. It puts the socket into the NO_COMMUNICATION
 * state.
 */
static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);

	if (scp->state == DN_CI) {
		scp->state = DN_NC;
		sk->sk_state = TCP_CLOSE;
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
	}

	kfree_skb(skb);
}

static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
{
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	int ret = NET_RX_DROP;

	/* Must not reply to returned packets */
	if (cb->rt_flags & DN_RT_F_RTS)
		goto out;

	if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
J
Joe Perches 已提交
699 700 701 702 703 704 705 706 707 708
		switch (cb->nsp_flags & 0x70) {
		case 0x10:
		case 0x60: /* (Retransmitted) Connect Init */
			dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
			ret = NET_RX_SUCCESS;
			break;
		case 0x20: /* Connect Confirm */
			dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
			ret = NET_RX_SUCCESS;
			break;
L
Linus Torvalds 已提交
709 710 711 712 713 714 715 716
		}
	}

out:
	kfree_skb(skb);
	return ret;
}

717
static int dn_nsp_rx_packet(struct sock *sk2, struct sk_buff *skb)
L
Linus Torvalds 已提交
718 719 720 721 722 723 724 725 726
{
	struct dn_skb_cb *cb = DN_SKB_CB(skb);
	struct sock *sk = NULL;
	unsigned char *ptr = (unsigned char *)skb->data;
	unsigned short reason = NSP_REASON_NL;

	if (!pskb_may_pull(skb, 2))
		goto free_out;

727
	skb_reset_transport_header(skb);
L
Linus Torvalds 已提交
728 729 730 731 732
	cb->nsp_flags = *ptr++;

	if (decnet_debug_level & 2)
		printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);

733
	if (cb->nsp_flags & 0x83)
L
Linus Torvalds 已提交
734 735 736 737 738 739
		goto free_out;

	/*
	 * Filter out conninits and useless packet types
	 */
	if ((cb->nsp_flags & 0x0c) == 0x08) {
J
Joe Perches 已提交
740 741 742 743 744 745 746 747
		switch (cb->nsp_flags & 0x70) {
		case 0x00: /* NOP */
		case 0x70: /* Reserved */
		case 0x50: /* Reserved, Phase II node init */
			goto free_out;
		case 0x10:
		case 0x60:
			if (unlikely(cb->rt_flags & DN_RT_F_RTS))
L
Linus Torvalds 已提交
748
				goto free_out;
J
Joe Perches 已提交
749 750
			sk = dn_find_listener(skb, &reason);
			goto got_it;
L
Linus Torvalds 已提交
751 752 753 754 755 756 757 758 759
		}
	}

	if (!pskb_may_pull(skb, 3))
		goto free_out;

	/*
	 * Grab the destination address.
	 */
760
	cb->dst_port = *(__le16 *)ptr;
L
Linus Torvalds 已提交
761 762 763 764 765 766 767
	cb->src_port = 0;
	ptr += 2;

	/*
	 * If not a connack, grab the source address too.
	 */
	if (pskb_may_pull(skb, 5)) {
768
		cb->src_port = *(__le16 *)ptr;
L
Linus Torvalds 已提交
769 770 771 772 773 774 775 776 777
		ptr += 2;
		skb_pull(skb, 5);
	}

	/*
	 * Returned packets...
	 * Swap src & dst and look up in the normal way.
	 */
	if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
778
		__le16 tmp = cb->dst_port;
L
Linus Torvalds 已提交
779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
		cb->dst_port = cb->src_port;
		cb->src_port = tmp;
		tmp = cb->dst;
		cb->dst = cb->src;
		cb->src = tmp;
	}

	/*
	 * Find the socket to which this skb is destined.
	 */
	sk = dn_find_by_skb(skb);
got_it:
	if (sk != NULL) {
		struct dn_scp *scp = DN_SK(sk);

		/* Reset backoff */
		scp->nsp_rxtshift = 0;

		/*
		 * We linearize everything except data segments here.
		 */
		if (cb->nsp_flags & ~0x60) {
H
Herbert Xu 已提交
801
			if (unlikely(skb_linearize(skb)))
L
Linus Torvalds 已提交
802 803 804
				goto free_out;
		}

805
		return sk_receive_skb(sk, skb, 0);
L
Linus Torvalds 已提交
806 807 808 809 810 811 812 813 814 815 816
	}

	return dn_nsp_no_socket(skb, reason);

free_out:
	kfree_skb(skb);
	return NET_RX_DROP;
}

int dn_nsp_rx(struct sk_buff *skb)
{
817 818
	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, NULL, skb,
		       skb->dev, NULL,
819
		       dn_nsp_rx_packet);
L
Linus Torvalds 已提交
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
}

/*
 * This is the main receive routine for sockets. It is called
 * from the above when the socket is not busy, and also from
 * sock_release() when there is a backlog queued up.
 */
int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = DN_SK(sk);
	struct dn_skb_cb *cb = DN_SKB_CB(skb);

	if (cb->rt_flags & DN_RT_F_RTS) {
		if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
			dn_returned_conn_init(sk, skb);
		else
			kfree_skb(skb);
		return NET_RX_SUCCESS;
	}

	/*
	 * Control packet.
	 */
	if ((cb->nsp_flags & 0x0c) == 0x08) {
J
Joe Perches 已提交
844 845 846 847 848 849 850 851 852 853 854 855 856 857
		switch (cb->nsp_flags & 0x70) {
		case 0x10:
		case 0x60:
			dn_nsp_conn_init(sk, skb);
			break;
		case 0x20:
			dn_nsp_conn_conf(sk, skb);
			break;
		case 0x30:
			dn_nsp_disc_init(sk, skb);
			break;
		case 0x40:
			dn_nsp_disc_conf(sk, skb);
			break;
L
Linus Torvalds 已提交
858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897
		}

	} else if (cb->nsp_flags == 0x24) {
		/*
		 * Special for connacks, 'cos they don't have
		 * ack data or ack otherdata info.
		 */
		dn_nsp_conn_ack(sk, skb);
	} else {
		int other = 1;

		/* both data and ack frames can kick a CC socket into RUN */
		if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
			scp->state = DN_RUN;
			sk->sk_state = TCP_ESTABLISHED;
			sk->sk_state_change(sk);
		}

		if ((cb->nsp_flags & 0x1c) == 0)
			other = 0;
		if (cb->nsp_flags == 0x04)
			other = 0;

		/*
		 * Read out ack data here, this applies equally
		 * to data, other data, link serivce and both
		 * ack data and ack otherdata.
		 */
		dn_process_ack(sk, skb, other);

		/*
		 * If we've some sort of data here then call a
		 * suitable routine for dealing with it, otherwise
		 * the packet is an ack and can be discarded.
		 */
		if ((cb->nsp_flags & 0x0c) == 0) {

			if (scp->state != DN_RUN)
				goto free_out;

J
Joe Perches 已提交
898 899 900 901 902 903 904 905 906
			switch (cb->nsp_flags) {
			case 0x10: /* LS */
				dn_nsp_linkservice(sk, skb);
				break;
			case 0x30: /* OD */
				dn_nsp_otherdata(sk, skb);
				break;
			default:
				dn_nsp_data(sk, skb);
L
Linus Torvalds 已提交
907 908 909 910 911 912 913 914 915 916 917
			}

		} else { /* Ack, chuck it out here */
free_out:
			kfree_skb(skb);
		}
	}

	return NET_RX_SUCCESS;
}