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 int skb_len; 589 590 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces 591 number of warnings when compiling with -W --ANK 592 */ 593 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 594 (unsigned int)sk->sk_rcvbuf) { 595 err = -ENOMEM; 596 goto out; 597 } 598 599 err = sk_filter(sk, skb); 600 if (err) 601 goto out; 602 603 skb_len = skb->len; 604 skb_set_owner_r(skb, sk); 605 skb_queue_tail(queue, skb); 606 607 if (!sock_flag(sk, SOCK_DEAD)) 608 sk->sk_data_ready(sk, skb_len); 609out: 610 return err; 611} 612 613static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb) 614{ 615 struct dn_scp *scp = DN_SK(sk); 616 unsigned short segnum; 617 struct dn_skb_cb *cb = DN_SKB_CB(skb); 618 int queued = 0; 619 620 if (skb->len < 2) 621 goto out; 622 623 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data); 624 skb_pull(skb, 2); 625 626 if (seq_next(scp->numoth_rcv, segnum)) { 627 628 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) { 629 seq_add(&scp->numoth_rcv, 1); 630 scp->other_report = 0; 631 queued = 1; 632 } 633 } 634 635 dn_nsp_send_oth_ack(sk); 636out: 637 if (!queued) 638 kfree_skb(skb); 639} 640 641static void dn_nsp_data(struct sock *sk, struct sk_buff *skb) 642{ 643 int queued = 0; 644 unsigned short segnum; 645 struct dn_skb_cb *cb = DN_SKB_CB(skb); 646 struct dn_scp *scp = DN_SK(sk); 647 648 if (skb->len < 2) 649 goto out; 650 651 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data); 652 skb_pull(skb, 2); 653 654 if (seq_next(scp->numdat_rcv, segnum)) { 655 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) { 656 seq_add(&scp->numdat_rcv, 1); 657 queued = 1; 658 } 659 660 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) { 661 scp->flowloc_sw = DN_DONTSEND; 662 dn_nsp_send_link(sk, DN_DONTSEND, 0); 663 } 664 } 665 666 dn_nsp_send_data_ack(sk); 667out: 668 if (!queued) 669 kfree_skb(skb); 670} 671 672/* 673 * If one of our conninit messages is returned, this function 674 * deals with it. It puts the socket into the NO_COMMUNICATION 675 * state. 676 */ 677static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb) 678{ 679 struct dn_scp *scp = DN_SK(sk); 680 681 if (scp->state == DN_CI) { 682 scp->state = DN_NC; 683 sk->sk_state = TCP_CLOSE; 684 if (!sock_flag(sk, SOCK_DEAD)) 685 sk->sk_state_change(sk); 686 } 687 688 kfree_skb(skb); 689} 690 691static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason) 692{ 693 struct dn_skb_cb *cb = DN_SKB_CB(skb); 694 int ret = NET_RX_DROP; 695 696 /* Must not reply to returned packets */ 697 if (cb->rt_flags & DN_RT_F_RTS) 698 goto out; 699 700 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) { 701 switch (cb->nsp_flags & 0x70) { 702 case 0x10: 703 case 0x60: /* (Retransmitted) Connect Init */ 704 dn_nsp_return_disc(skb, NSP_DISCINIT, reason); 705 ret = NET_RX_SUCCESS; 706 break; 707 case 0x20: /* Connect Confirm */ 708 dn_nsp_return_disc(skb, NSP_DISCCONF, reason); 709 ret = NET_RX_SUCCESS; 710 break; 711 } 712 } 713 714out: 715 kfree_skb(skb); 716 return ret; 717} 718 719static int dn_nsp_rx_packet(struct sk_buff *skb) 720{ 721 struct dn_skb_cb *cb = DN_SKB_CB(skb); 722 struct sock *sk = NULL; 723 unsigned char *ptr = (unsigned char *)skb->data; 724 unsigned short reason = NSP_REASON_NL; 725 726 if (!pskb_may_pull(skb, 2)) 727 goto free_out; 728 729 skb_reset_transport_header(skb); 730 cb->nsp_flags = *ptr++; 731 732 if (decnet_debug_level & 2) 733 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags); 734 735 if (cb->nsp_flags & 0x83) 736 goto free_out; 737 738 /* 739 * Filter out conninits and useless packet types 740 */ 741 if ((cb->nsp_flags & 0x0c) == 0x08) { 742 switch (cb->nsp_flags & 0x70) { 743 case 0x00: /* NOP */ 744 case 0x70: /* Reserved */ 745 case 0x50: /* Reserved, Phase II node init */ 746 goto free_out; 747 case 0x10: 748 case 0x60: 749 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) 750 goto free_out; 751 sk = dn_find_listener(skb, &reason); 752 goto got_it; 753 } 754 } 755 756 if (!pskb_may_pull(skb, 3)) 757 goto free_out; 758 759 /* 760 * Grab the destination address. 761 */ 762 cb->dst_port = *(__le16 *)ptr; 763 cb->src_port = 0; 764 ptr += 2; 765 766 /* 767 * If not a connack, grab the source address too. 768 */ 769 if (pskb_may_pull(skb, 5)) { 770 cb->src_port = *(__le16 *)ptr; 771 ptr += 2; 772 skb_pull(skb, 5); 773 } 774 775 /* 776 * Returned packets... 777 * Swap src & dst and look up in the normal way. 778 */ 779 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) { 780 __le16 tmp = cb->dst_port; 781 cb->dst_port = cb->src_port; 782 cb->src_port = tmp; 783 tmp = cb->dst; 784 cb->dst = cb->src; 785 cb->src = tmp; 786 } 787 788 /* 789 * Find the socket to which this skb is destined. 790 */ 791 sk = dn_find_by_skb(skb); 792got_it: 793 if (sk != NULL) { 794 struct dn_scp *scp = DN_SK(sk); 795 796 /* Reset backoff */ 797 scp->nsp_rxtshift = 0; 798 799 /* 800 * We linearize everything except data segments here. 801 */ 802 if (cb->nsp_flags & ~0x60) { 803 if (unlikely(skb_linearize(skb))) 804 goto free_out; 805 } 806 807 return sk_receive_skb(sk, skb, 0); 808 } 809 810 return dn_nsp_no_socket(skb, reason); 811 812free_out: 813 kfree_skb(skb); 814 return NET_RX_DROP; 815} 816 817int dn_nsp_rx(struct sk_buff *skb) 818{ 819 return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, 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} 918 919