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 <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.h> 76#include <net/dn_nsp.h> 77#include <net/dn_dev.h> 78#include <net/dn_route.h> 79 80extern int decnet_log_martians; 81 82static void dn_log_martian(struct sk_buff *skb, const char *msg) 83{ 84 if (decnet_log_martians && net_ratelimit()) { 85 char *devname = skb->dev ? skb->dev->name : "???"; 86 struct dn_skb_cb *cb = DN_SKB_CB(skb); 87 printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n", 88 msg, devname, le16_to_cpu(cb->src), le16_to_cpu(cb->dst), 89 le16_to_cpu(cb->src_port), le16_to_cpu(cb->dst_port)); 90 } 91} 92 93/* 94 * For this function we've flipped the cross-subchannel bit 95 * if the message is an otherdata or linkservice message. Thus 96 * we can use it to work out what to update. 97 */ 98static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack) 99{ 100 struct dn_scp *scp = DN_SK(sk); 101 unsigned short type = ((ack >> 12) & 0x0003); 102 int wakeup = 0; 103 104 switch(type) { 105 case 0: /* ACK - Data */ 106 if (dn_after(ack, scp->ackrcv_dat)) { 107 scp->ackrcv_dat = ack & 0x0fff; 108 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack); 109 } 110 break; 111 case 1: /* NAK - Data */ 112 break; 113 case 2: /* ACK - OtherData */ 114 if (dn_after(ack, scp->ackrcv_oth)) { 115 scp->ackrcv_oth = ack & 0x0fff; 116 wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack); 117 } 118 break; 119 case 3: /* NAK - OtherData */ 120 break; 121 } 122 123 if (wakeup && !sock_flag(sk, SOCK_DEAD)) 124 sk->sk_state_change(sk); 125} 126 127/* 128 * This function is a universal ack processor. 129 */ 130static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth) 131{ 132 __le16 *ptr = (__le16 *)skb->data; 133 int len = 0; 134 unsigned short ack; 135 136 if (skb->len < 2) 137 return len; 138 139 if ((ack = le16_to_cpu(*ptr)) & 0x8000) { 140 skb_pull(skb, 2); 141 ptr++; 142 len += 2; 143 if ((ack & 0x4000) == 0) { 144 if (oth) 145 ack ^= 0x2000; 146 dn_ack(sk, skb, ack); 147 } 148 } 149 150 if (skb->len < 2) 151 return len; 152 153 if ((ack = le16_to_cpu(*ptr)) & 0x8000) { 154 skb_pull(skb, 2); 155 len += 2; 156 if ((ack & 0x4000) == 0) { 157 if (oth) 158 ack ^= 0x2000; 159 dn_ack(sk, skb, ack); 160 } 161 } 162 163 return len; 164} 165 166 167/** 168 * dn_check_idf - Check an image data field format is correct. 169 * @pptr: Pointer to pointer to image data 170 * @len: Pointer to length of image data 171 * @max: The maximum allowed length of the data in the image data field 172 * @follow_on: Check that this many bytes exist beyond the end of the image data 173 * 174 * Returns: 0 if ok, -1 on error 175 */ 176static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on) 177{ 178 unsigned char *ptr = *pptr; 179 unsigned char flen = *ptr++; 180 181 (*len)--; 182 if (flen > max) 183 return -1; 184 if ((flen + follow_on) > *len) 185 return -1; 186 187 *len -= flen; 188 *pptr = ptr + flen; 189 return 0; 190} 191 192/* 193 * Table of reason codes to pass back to node which sent us a badly 194 * formed message, plus text messages for the log. A zero entry in 195 * the reason field means "don't reply" otherwise a disc init is sent with 196 * the specified reason code. 197 */ 198static struct { 199 unsigned short reason; 200 const char *text; 201} ci_err_table[] = { 202 { 0, "CI: Truncated message" }, 203 { NSP_REASON_ID, "CI: Destination username error" }, 204 { NSP_REASON_ID, "CI: Destination username type" }, 205 { NSP_REASON_US, "CI: Source username error" }, 206 { 0, "CI: Truncated at menuver" }, 207 { 0, "CI: Truncated before access or user data" }, 208 { NSP_REASON_IO, "CI: Access data format error" }, 209 { NSP_REASON_IO, "CI: User data format error" } 210}; 211 212/* 213 * This function uses a slightly different lookup method 214 * to find its sockets, since it searches on object name/number 215 * rather than port numbers. Various tests are done to ensure that 216 * the incoming data is in the correct format before it is queued to 217 * a socket. 218 */ 219static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason) 220{ 221 struct dn_skb_cb *cb = DN_SKB_CB(skb); 222 struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data; 223 struct sockaddr_dn dstaddr; 224 struct sockaddr_dn srcaddr; 225 unsigned char type = 0; 226 int dstlen; 227 int srclen; 228 unsigned char *ptr; 229 int len; 230 int err = 0; 231 unsigned char menuver; 232 233 memset(&dstaddr, 0, sizeof(struct sockaddr_dn)); 234 memset(&srcaddr, 0, sizeof(struct sockaddr_dn)); 235 236 /* 237 * 1. Decode & remove message header 238 */ 239 cb->src_port = msg->srcaddr; 240 cb->dst_port = msg->dstaddr; 241 cb->services = msg->services; 242 cb->info = msg->info; 243 cb->segsize = le16_to_cpu(msg->segsize); 244 245 if (!pskb_may_pull(skb, sizeof(*msg))) 246 goto err_out; 247 248 skb_pull(skb, sizeof(*msg)); 249 250 len = skb->len; 251 ptr = skb->data; 252 253 /* 254 * 2. Check destination end username format 255 */ 256 dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type); 257 err++; 258 if (dstlen < 0) 259 goto err_out; 260 261 err++; 262 if (type > 1) 263 goto err_out; 264 265 len -= dstlen; 266 ptr += dstlen; 267 268 /* 269 * 3. Check source end username format 270 */ 271 srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type); 272 err++; 273 if (srclen < 0) 274 goto err_out; 275 276 len -= srclen; 277 ptr += srclen; 278 err++; 279 if (len < 1) 280 goto err_out; 281 282 menuver = *ptr; 283 ptr++; 284 len--; 285 286 /* 287 * 4. Check that optional data actually exists if menuver says it does 288 */ 289 err++; 290 if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1)) 291 goto err_out; 292 293 /* 294 * 5. Check optional access data format 295 */ 296 err++; 297 if (menuver & DN_MENUVER_ACC) { 298 if (dn_check_idf(&ptr, &len, 39, 1)) 299 goto err_out; 300 if (dn_check_idf(&ptr, &len, 39, 1)) 301 goto err_out; 302 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0)) 303 goto err_out; 304 } 305 306 /* 307 * 6. Check optional user data format 308 */ 309 err++; 310 if (menuver & DN_MENUVER_USR) { 311 if (dn_check_idf(&ptr, &len, 16, 0)) 312 goto err_out; 313 } 314 315 /* 316 * 7. Look up socket based on destination end username 317 */ 318 return dn_sklist_find_listener(&dstaddr); 319err_out: 320 dn_log_martian(skb, ci_err_table[err].text); 321 *reason = ci_err_table[err].reason; 322 return NULL; 323} 324 325 326static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb) 327{ 328 if (sk_acceptq_is_full(sk)) { 329 kfree_skb(skb); 330 return; 331 } 332 333 sk->sk_ack_backlog++; 334 skb_queue_tail(&sk->sk_receive_queue, skb); 335 sk->sk_state_change(sk); 336} 337 338static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb) 339{ 340 struct dn_skb_cb *cb = DN_SKB_CB(skb); 341 struct dn_scp *scp = DN_SK(sk); 342 unsigned char *ptr; 343 344 if (skb->len < 4) 345 goto out; 346 347 ptr = skb->data; 348 cb->services = *ptr++; 349 cb->info = *ptr++; 350 cb->segsize = le16_to_cpu(*(__le16 *)ptr); 351 352 if ((scp->state == DN_CI) || (scp->state == DN_CD)) { 353 scp->persist = 0; 354 scp->addrrem = cb->src_port; 355 sk->sk_state = TCP_ESTABLISHED; 356 scp->state = DN_RUN; 357 scp->services_rem = cb->services; 358 scp->info_rem = cb->info; 359 scp->segsize_rem = cb->segsize; 360 361 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE) 362 scp->max_window = decnet_no_fc_max_cwnd; 363 364 if (skb->len > 0) { 365 u16 dlen = *skb->data; 366 if ((dlen <= 16) && (dlen <= skb->len)) { 367 scp->conndata_in.opt_optl = cpu_to_le16(dlen); 368 skb_copy_from_linear_data_offset(skb, 1, 369 scp->conndata_in.opt_data, dlen); 370 } 371 } 372 dn_nsp_send_link(sk, DN_NOCHANGE, 0); 373 if (!sock_flag(sk, SOCK_DEAD)) 374 sk->sk_state_change(sk); 375 } 376 377out: 378 kfree_skb(skb); 379} 380 381static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb) 382{ 383 struct dn_scp *scp = DN_SK(sk); 384 385 if (scp->state == DN_CI) { 386 scp->state = DN_CD; 387 scp->persist = 0; 388 } 389 390 kfree_skb(skb); 391} 392 393static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb) 394{ 395 struct dn_scp *scp = DN_SK(sk); 396 struct dn_skb_cb *cb = DN_SKB_CB(skb); 397 unsigned short reason; 398 399 if (skb->len < 2) 400 goto out; 401 402 reason = le16_to_cpu(*(__le16 *)skb->data); 403 skb_pull(skb, 2); 404 405 scp->discdata_in.opt_status = cpu_to_le16(reason); 406 scp->discdata_in.opt_optl = 0; 407 memset(scp->discdata_in.opt_data, 0, 16); 408 409 if (skb->len > 0) { 410 u16 dlen = *skb->data; 411 if ((dlen <= 16) && (dlen <= skb->len)) { 412 scp->discdata_in.opt_optl = cpu_to_le16(dlen); 413 skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen); 414 } 415 } 416 417 scp->addrrem = cb->src_port; 418 sk->sk_state = TCP_CLOSE; 419 420 switch(scp->state) { 421 case DN_CI: 422 case DN_CD: 423 scp->state = DN_RJ; 424 sk->sk_err = ECONNREFUSED; 425 break; 426 case DN_RUN: 427 sk->sk_shutdown |= SHUTDOWN_MASK; 428 scp->state = DN_DN; 429 break; 430 case DN_DI: 431 scp->state = DN_DIC; 432 break; 433 } 434 435 if (!sock_flag(sk, SOCK_DEAD)) { 436 if (sk->sk_socket->state != SS_UNCONNECTED) 437 sk->sk_socket->state = SS_DISCONNECTING; 438 sk->sk_state_change(sk); 439 } 440 441 /* 442 * It appears that its possible for remote machines to send disc 443 * init messages with no port identifier if we are in the CI and 444 * possibly also the CD state. Obviously we shouldn't reply with 445 * a message if we don't know what the end point is. 446 */ 447 if (scp->addrrem) { 448 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC); 449 } 450 scp->persist_fxn = dn_destroy_timer; 451 scp->persist = dn_nsp_persist(sk); 452 453out: 454 kfree_skb(skb); 455} 456 457/* 458 * disc_conf messages are also called no_resources or no_link 459 * messages depending upon the "reason" field. 460 */ 461static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb) 462{ 463 struct dn_scp *scp = DN_SK(sk); 464 unsigned short reason; 465 466 if (skb->len != 2) 467 goto out; 468 469 reason = le16_to_cpu(*(__le16 *)skb->data); 470 471 sk->sk_state = TCP_CLOSE; 472 473 switch(scp->state) { 474 case DN_CI: 475 scp->state = DN_NR; 476 break; 477 case DN_DR: 478 if (reason == NSP_REASON_DC) 479 scp->state = DN_DRC; 480 if (reason == NSP_REASON_NL) 481 scp->state = DN_CN; 482 break; 483 case DN_DI: 484 scp->state = DN_DIC; 485 break; 486 case DN_RUN: 487 sk->sk_shutdown |= SHUTDOWN_MASK; 488 case DN_CC: 489 scp->state = DN_CN; 490 } 491 492 if (!sock_flag(sk, SOCK_DEAD)) { 493 if (sk->sk_socket->state != SS_UNCONNECTED) 494 sk->sk_socket->state = SS_DISCONNECTING; 495 sk->sk_state_change(sk); 496 } 497 498 scp->persist_fxn = dn_destroy_timer; 499 scp->persist = dn_nsp_persist(sk); 500 501out: 502 kfree_skb(skb); 503} 504 505static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb) 506{ 507 struct dn_scp *scp = DN_SK(sk); 508 unsigned short segnum; 509 unsigned char lsflags; 510 signed char fcval; 511 int wake_up = 0; 512 char *ptr = skb->data; 513 unsigned char fctype = scp->services_rem & NSP_FC_MASK; 514 515 if (skb->len != 4) 516 goto out; 517 518 segnum = le16_to_cpu(*(__le16 *)ptr); 519 ptr += 2; 520 lsflags = *(unsigned char *)ptr++; 521 fcval = *ptr; 522 523 /* 524 * Here we ignore erronous packets which should really 525 * should cause a connection abort. It is not critical 526 * for now though. 527 */ 528 if (lsflags & 0xf8) 529 goto out; 530 531 if (seq_next(scp->numoth_rcv, segnum)) { 532 seq_add(&scp->numoth_rcv, 1); 533 switch(lsflags & 0x04) { /* FCVAL INT */ 534 case 0x00: /* Normal Request */ 535 switch(lsflags & 0x03) { /* FCVAL MOD */ 536 case 0x00: /* Request count */ 537 if (fcval < 0) { 538 unsigned char p_fcval = -fcval; 539 if ((scp->flowrem_dat > p_fcval) && 540 (fctype == NSP_FC_SCMC)) { 541 scp->flowrem_dat -= p_fcval; 542 } 543 } else if (fcval > 0) { 544 scp->flowrem_dat += fcval; 545 wake_up = 1; 546 } 547 break; 548 case 0x01: /* Stop outgoing data */ 549 scp->flowrem_sw = DN_DONTSEND; 550 break; 551 case 0x02: /* Ok to start again */ 552 scp->flowrem_sw = DN_SEND; 553 dn_nsp_output(sk); 554 wake_up = 1; 555 } 556 break; 557 case 0x04: /* Interrupt Request */ 558 if (fcval > 0) { 559 scp->flowrem_oth += fcval; 560 wake_up = 1; 561 } 562 break; 563 } 564 if (wake_up && !sock_flag(sk, SOCK_DEAD)) 565 sk->sk_state_change(sk); 566 } 567 568 dn_nsp_send_oth_ack(sk); 569 570out: 571 kfree_skb(skb); 572} 573 574/* 575 * Copy of sock_queue_rcv_skb (from sock.h) without 576 * bh_lock_sock() (its already held when this is called) which 577 * also allows data and other data to be queued to a socket. 578 */ 579static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue) 580{ 581 int err; 582 int skb_len; 583 584 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces 585 number of warnings when compiling with -W --ANK 586 */ 587 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 588 (unsigned)sk->sk_rcvbuf) { 589 err = -ENOMEM; 590 goto out; 591 } 592 593 err = sk_filter(sk, skb); 594 if (err) 595 goto out; 596 597 skb_len = skb->len; 598 skb_set_owner_r(skb, sk); 599 skb_queue_tail(queue, skb); 600 601 if (!sock_flag(sk, SOCK_DEAD)) 602 sk->sk_data_ready(sk, skb_len); 603out: 604 return err; 605} 606 607static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb) 608{ 609 struct dn_scp *scp = DN_SK(sk); 610 unsigned short segnum; 611 struct dn_skb_cb *cb = DN_SKB_CB(skb); 612 int queued = 0; 613 614 if (skb->len < 2) 615 goto out; 616 617 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data); 618 skb_pull(skb, 2); 619 620 if (seq_next(scp->numoth_rcv, segnum)) { 621 622 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) { 623 seq_add(&scp->numoth_rcv, 1); 624 scp->other_report = 0; 625 queued = 1; 626 } 627 } 628 629 dn_nsp_send_oth_ack(sk); 630out: 631 if (!queued) 632 kfree_skb(skb); 633} 634 635static void dn_nsp_data(struct sock *sk, struct sk_buff *skb) 636{ 637 int queued = 0; 638 unsigned short segnum; 639 struct dn_skb_cb *cb = DN_SKB_CB(skb); 640 struct dn_scp *scp = DN_SK(sk); 641 642 if (skb->len < 2) 643 goto out; 644 645 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data); 646 skb_pull(skb, 2); 647 648 if (seq_next(scp->numdat_rcv, segnum)) { 649 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) { 650 seq_add(&scp->numdat_rcv, 1); 651 queued = 1; 652 } 653 654 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) { 655 scp->flowloc_sw = DN_DONTSEND; 656 dn_nsp_send_link(sk, DN_DONTSEND, 0); 657 } 658 } 659 660 dn_nsp_send_data_ack(sk); 661out: 662 if (!queued) 663 kfree_skb(skb); 664} 665 666/* 667 * If one of our conninit messages is returned, this function 668 * deals with it. It puts the socket into the NO_COMMUNICATION 669 * state. 670 */ 671static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb) 672{ 673 struct dn_scp *scp = DN_SK(sk); 674 675 if (scp->state == DN_CI) { 676 scp->state = DN_NC; 677 sk->sk_state = TCP_CLOSE; 678 if (!sock_flag(sk, SOCK_DEAD)) 679 sk->sk_state_change(sk); 680 } 681 682 kfree_skb(skb); 683} 684 685static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason) 686{ 687 struct dn_skb_cb *cb = DN_SKB_CB(skb); 688 int ret = NET_RX_DROP; 689 690 /* Must not reply to returned packets */ 691 if (cb->rt_flags & DN_RT_F_RTS) 692 goto out; 693 694 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) { 695 switch(cb->nsp_flags & 0x70) { 696 case 0x10: 697 case 0x60: /* (Retransmitted) Connect Init */ 698 dn_nsp_return_disc(skb, NSP_DISCINIT, reason); 699 ret = NET_RX_SUCCESS; 700 break; 701 case 0x20: /* Connect Confirm */ 702 dn_nsp_return_disc(skb, NSP_DISCCONF, reason); 703 ret = NET_RX_SUCCESS; 704 break; 705 } 706 } 707 708out: 709 kfree_skb(skb); 710 return ret; 711} 712 713static int dn_nsp_rx_packet(struct sk_buff *skb) 714{ 715 struct dn_skb_cb *cb = DN_SKB_CB(skb); 716 struct sock *sk = NULL; 717 unsigned char *ptr = (unsigned char *)skb->data; 718 unsigned short reason = NSP_REASON_NL; 719 720 if (!pskb_may_pull(skb, 2)) 721 goto free_out; 722 723 skb_reset_transport_header(skb); 724 cb->nsp_flags = *ptr++; 725 726 if (decnet_debug_level & 2) 727 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags); 728 729 if (cb->nsp_flags & 0x83) 730 goto free_out; 731 732 /* 733 * Filter out conninits and useless packet types 734 */ 735 if ((cb->nsp_flags & 0x0c) == 0x08) { 736 switch(cb->nsp_flags & 0x70) { 737 case 0x00: /* NOP */ 738 case 0x70: /* Reserved */ 739 case 0x50: /* Reserved, Phase II node init */ 740 goto free_out; 741 case 0x10: 742 case 0x60: 743 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) 744 goto free_out; 745 sk = dn_find_listener(skb, &reason); 746 goto got_it; 747 } 748 } 749 750 if (!pskb_may_pull(skb, 3)) 751 goto free_out; 752 753 /* 754 * Grab the destination address. 755 */ 756 cb->dst_port = *(__le16 *)ptr; 757 cb->src_port = 0; 758 ptr += 2; 759 760 /* 761 * If not a connack, grab the source address too. 762 */ 763 if (pskb_may_pull(skb, 5)) { 764 cb->src_port = *(__le16 *)ptr; 765 ptr += 2; 766 skb_pull(skb, 5); 767 } 768 769 /* 770 * Returned packets... 771 * Swap src & dst and look up in the normal way. 772 */ 773 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) { 774 __le16 tmp = cb->dst_port; 775 cb->dst_port = cb->src_port; 776 cb->src_port = tmp; 777 tmp = cb->dst; 778 cb->dst = cb->src; 779 cb->src = tmp; 780 } 781 782 /* 783 * Find the socket to which this skb is destined. 784 */ 785 sk = dn_find_by_skb(skb); 786got_it: 787 if (sk != NULL) { 788 struct dn_scp *scp = DN_SK(sk); 789 790 /* Reset backoff */ 791 scp->nsp_rxtshift = 0; 792 793 /* 794 * We linearize everything except data segments here. 795 */ 796 if (cb->nsp_flags & ~0x60) { 797 if (unlikely(skb_linearize(skb))) 798 goto free_out; 799 } 800 801 return sk_receive_skb(sk, skb, 0); 802 } 803 804 return dn_nsp_no_socket(skb, reason); 805 806free_out: 807 kfree_skb(skb); 808 return NET_RX_DROP; 809} 810 811int dn_nsp_rx(struct sk_buff *skb) 812{ 813 return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, skb, skb->dev, NULL, 814 dn_nsp_rx_packet); 815} 816 817/* 818 * This is the main receive routine for sockets. It is called 819 * from the above when the socket is not busy, and also from 820 * sock_release() when there is a backlog queued up. 821 */ 822int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb) 823{ 824 struct dn_scp *scp = DN_SK(sk); 825 struct dn_skb_cb *cb = DN_SKB_CB(skb); 826 827 if (cb->rt_flags & DN_RT_F_RTS) { 828 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68) 829 dn_returned_conn_init(sk, skb); 830 else 831 kfree_skb(skb); 832 return NET_RX_SUCCESS; 833 } 834 835 /* 836 * Control packet. 837 */ 838 if ((cb->nsp_flags & 0x0c) == 0x08) { 839 switch(cb->nsp_flags & 0x70) { 840 case 0x10: 841 case 0x60: 842 dn_nsp_conn_init(sk, skb); 843 break; 844 case 0x20: 845 dn_nsp_conn_conf(sk, skb); 846 break; 847 case 0x30: 848 dn_nsp_disc_init(sk, skb); 849 break; 850 case 0x40: 851 dn_nsp_disc_conf(sk, skb); 852 break; 853 } 854 855 } else if (cb->nsp_flags == 0x24) { 856 /* 857 * Special for connacks, 'cos they don't have 858 * ack data or ack otherdata info. 859 */ 860 dn_nsp_conn_ack(sk, skb); 861 } else { 862 int other = 1; 863 864 /* both data and ack frames can kick a CC socket into RUN */ 865 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) { 866 scp->state = DN_RUN; 867 sk->sk_state = TCP_ESTABLISHED; 868 sk->sk_state_change(sk); 869 } 870 871 if ((cb->nsp_flags & 0x1c) == 0) 872 other = 0; 873 if (cb->nsp_flags == 0x04) 874 other = 0; 875 876 /* 877 * Read out ack data here, this applies equally 878 * to data, other data, link serivce and both 879 * ack data and ack otherdata. 880 */ 881 dn_process_ack(sk, skb, other); 882 883 /* 884 * If we've some sort of data here then call a 885 * suitable routine for dealing with it, otherwise 886 * the packet is an ack and can be discarded. 887 */ 888 if ((cb->nsp_flags & 0x0c) == 0) { 889 890 if (scp->state != DN_RUN) 891 goto free_out; 892 893 switch(cb->nsp_flags) { 894 case 0x10: /* LS */ 895 dn_nsp_linkservice(sk, skb); 896 break; 897 case 0x30: /* OD */ 898 dn_nsp_otherdata(sk, skb); 899 break; 900 default: 901 dn_nsp_data(sk, skb); 902 } 903 904 } else { /* Ack, chuck it out here */ 905free_out: 906 kfree_skb(skb); 907 } 908 } 909 910 return NET_RX_SUCCESS; 911} 912