net/tipc/msg.c

   1 /*
   2  * net/tipc/msg.c: TIPC message header routines
   3  *
   4  * Copyright (c) 2000-2006, 2014-2015, Ericsson AB
   5  * Copyright (c) 2005, 2010-2011, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include <net/sock.h>
  38 #include "core.h"
  39 #include "msg.h"
  40 #include "addr.h"
  41 #include "name_table.h"
  42
  43 #define MAX_FORWARD_SIZE 1024
  44
  45 static unsigned int align(unsigned int i)
  46 {
  47         return (i + 3) & ~3u;
  48 }
  49
  50 /**
  51  * tipc_buf_acquire - creates a TIPC message buffer
  52  * @size: message size (including TIPC header)
  53  *
  54  * Returns a new buffer with data pointers set to the specified size.
  55  *
  56  * NOTE: Headroom is reserved to allow prepending of a data link header.
  57  *       There may also be unrequested tailroom present at the buffer's end.
  58  */
  59 struct sk_buff *tipc_buf_acquire(u32 size)
  60 {
  61         struct sk_buff *skb;
  62         unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
  63
  64         skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
  65         if (skb) {
  66                 skb_reserve(skb, BUF_HEADROOM);
  67                 skb_put(skb, size);
  68                 skb->next = NULL;
  69         }
  70         return skb;
  71 }
  72
  73 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
  74                    u32 hsize, u32 dnode)
  75 {
  76         memset(m, 0, hsize);
  77         msg_set_version(m);
  78         msg_set_user(m, user);
  79         msg_set_hdr_sz(m, hsize);
  80         msg_set_size(m, hsize);
  81         msg_set_prevnode(m, own_node);
  82         msg_set_type(m, type);
  83         if (hsize > SHORT_H_SIZE) {
  84                 msg_set_orignode(m, own_node);
  85                 msg_set_destnode(m, dnode);
  86         }
  87 }
  88
  89 struct sk_buff *tipc_msg_create(uint user, uint type,
  90                                 uint hdr_sz, uint data_sz, u32 dnode,
  91                                 u32 onode, u32 dport, u32 oport, int errcode)
  92 {
  93         struct tipc_msg *msg;
  94         struct sk_buff *buf;
  95
  96         buf = tipc_buf_acquire(hdr_sz + data_sz);
  97         if (unlikely(!buf))
  98                 return NULL;
  99
 100         msg = buf_msg(buf);
 101         tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
 102         msg_set_size(msg, hdr_sz + data_sz);
 103         msg_set_origport(msg, oport);
 104         msg_set_destport(msg, dport);
 105         msg_set_errcode(msg, errcode);
 106         if (hdr_sz > SHORT_H_SIZE) {
 107                 msg_set_orignode(msg, onode);
 108                 msg_set_destnode(msg, dnode);
 109         }
 110         return buf;
 111 }
 112
 113 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
 114  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
 115  *            out: set when successful non-complete reassembly, otherwise NULL
 116  * @*buf:     in:  the buffer to append. Always defined
 117  *            out: head buf after successful complete reassembly, otherwise NULL
 118  * Returns 1 when reassembly complete, otherwise 0
 119  */
 120 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 121 {
 122         struct sk_buff *head = *headbuf;
 123         struct sk_buff *frag = *buf;
 124         struct sk_buff *tail;
 125         struct tipc_msg *msg;
 126         u32 fragid;
 127         int delta;
 128         bool headstolen;
 129
 130         if (!frag)
 131                 goto err;
 132
 133         msg = buf_msg(frag);
 134         fragid = msg_type(msg);
 135         frag->next = NULL;
 136         skb_pull(frag, msg_hdr_sz(msg));
 137
 138         if (fragid == FIRST_FRAGMENT) {
 139                 if (unlikely(head))
 140                         goto err;
 141                 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
 142                         goto err;
 143                 head = *headbuf = frag;
 144                 skb_frag_list_init(head);
 145                 TIPC_SKB_CB(head)->tail = NULL;
 146                 *buf = NULL;
 147                 return 0;
 148         }
 149
 150         if (!head)
 151                 goto err;
 152
 153         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 154                 kfree_skb_partial(frag, headstolen);
 155         } else {
 156                 tail = TIPC_SKB_CB(head)->tail;
 157                 if (!skb_has_frag_list(head))
 158                         skb_shinfo(head)->frag_list = frag;
 159                 else
 160                         tail->next = frag;
 161                 head->truesize += frag->truesize;
 162                 head->data_len += frag->len;
 163                 head->len += frag->len;
 164                 TIPC_SKB_CB(head)->tail = frag;
 165         }
 166
 167         if (fragid == LAST_FRAGMENT) {
 168                 TIPC_SKB_CB(head)->validated = false;
 169                 if (unlikely(!tipc_msg_validate(head)))
 170                         goto err;
 171                 *buf = head;
 172                 TIPC_SKB_CB(head)->tail = NULL;
 173                 *headbuf = NULL;
 174                 return 1;
 175         }
 176         *buf = NULL;
 177         return 0;
 178 err:
 179         pr_warn_ratelimited("Unable to build fragment list\n");
 180         kfree_skb(*buf);
 181         kfree_skb(*headbuf);
 182         *buf = *headbuf = NULL;
 183         return 0;
 184 }
 185
 186 /* tipc_msg_validate - validate basic format of received message
 187  *
 188  * This routine ensures a TIPC message has an acceptable header, and at least
 189  * as much data as the header indicates it should.  The routine also ensures
 190  * that the entire message header is stored in the main fragment of the message
 191  * buffer, to simplify future access to message header fields.
 192  *
 193  * Note: Having extra info present in the message header or data areas is OK.
 194  * TIPC will ignore the excess, under the assumption that it is optional info
 195  * introduced by a later release of the protocol.
 196  */
 197 bool tipc_msg_validate(struct sk_buff *skb)
 198 {
 199         struct tipc_msg *msg;
 200         int msz, hsz;
 201
 202         if (unlikely(TIPC_SKB_CB(skb)->validated))
 203                 return true;
 204         if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
 205                 return false;
 206
 207         hsz = msg_hdr_sz(buf_msg(skb));
 208         if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
 209                 return false;
 210         if (unlikely(!pskb_may_pull(skb, hsz)))
 211                 return false;
 212
 213         msg = buf_msg(skb);
 214         if (unlikely(msg_version(msg) != TIPC_VERSION))
 215                 return false;
 216
 217         msz = msg_size(msg);
 218         if (unlikely(msz < hsz))
 219                 return false;
 220         if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
 221                 return false;
 222         if (unlikely(skb->len < msz))
 223                 return false;
 224
 225         TIPC_SKB_CB(skb)->validated = true;
 226         return true;
 227 }
 228
 229 /**
 230  * tipc_msg_build - create buffer chain containing specified header and data
 231  * @mhdr: Message header, to be prepended to data
 232  * @m: User message
 233  * @dsz: Total length of user data
 234  * @pktmax: Max packet size that can be used
 235  * @list: Buffer or chain of buffers to be returned to caller
 236  *
 237  * Returns message data size or errno: -ENOMEM, -EFAULT
 238  */
 239 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 240                    int offset, int dsz, int pktmax, struct sk_buff_head *list)
 241 {
 242         int mhsz = msg_hdr_sz(mhdr);
 243         int msz = mhsz + dsz;
 244         int pktno = 1;
 245         int pktsz;
 246         int pktrem = pktmax;
 247         int drem = dsz;
 248         struct tipc_msg pkthdr;
 249         struct sk_buff *skb;
 250         char *pktpos;
 251         int rc;
 252
 253         msg_set_size(mhdr, msz);
 254
 255         /* No fragmentation needed? */
 256         if (likely(msz <= pktmax)) {
 257                 skb = tipc_buf_acquire(msz);
 258                 if (unlikely(!skb))
 259                         return -ENOMEM;
 260                 skb_orphan(skb);
 261                 __skb_queue_tail(list, skb);
 262                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 263                 pktpos = skb->data + mhsz;
 264                 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
 265                         return dsz;
 266                 rc = -EFAULT;
 267                 goto error;
 268         }
 269
 270         /* Prepare reusable fragment header */
 271         tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 272                       FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 273         msg_set_size(&pkthdr, pktmax);
 274         msg_set_fragm_no(&pkthdr, pktno);
 275         msg_set_importance(&pkthdr, msg_importance(mhdr));
 276
 277         /* Prepare first fragment */
 278         skb = tipc_buf_acquire(pktmax);
 279         if (!skb)
 280                 return -ENOMEM;
 281         skb_orphan(skb);
 282         __skb_queue_tail(list, skb);
 283         pktpos = skb->data;
 284         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 285         pktpos += INT_H_SIZE;
 286         pktrem -= INT_H_SIZE;
 287         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 288         pktpos += mhsz;
 289         pktrem -= mhsz;
 290
 291         do {
 292                 if (drem < pktrem)
 293                         pktrem = drem;
 294
 295                 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
 296                         rc = -EFAULT;
 297                         goto error;
 298                 }
 299                 drem -= pktrem;
 300
 301                 if (!drem)
 302                         break;
 303
 304                 /* Prepare new fragment: */
 305                 if (drem < (pktmax - INT_H_SIZE))
 306                         pktsz = drem + INT_H_SIZE;
 307                 else
 308                         pktsz = pktmax;
 309                 skb = tipc_buf_acquire(pktsz);
 310                 if (!skb) {
 311                         rc = -ENOMEM;
 312                         goto error;
 313                 }
 314                 skb_orphan(skb);
 315                 __skb_queue_tail(list, skb);
 316                 msg_set_type(&pkthdr, FRAGMENT);
 317                 msg_set_size(&pkthdr, pktsz);
 318                 msg_set_fragm_no(&pkthdr, ++pktno);
 319                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 320                 pktpos = skb->data + INT_H_SIZE;
 321                 pktrem = pktsz - INT_H_SIZE;
 322
 323         } while (1);
 324         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 325         return dsz;
 326 error:
 327         __skb_queue_purge(list);
 328         __skb_queue_head_init(list);
 329         return rc;
 330 }
 331
 332 /**
 333  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 334  * @skb: the buffer to append to ("bundle")
 335  * @msg:  message to be appended
 336  * @mtu:  max allowable size for the bundle buffer
 337  * Consumes buffer if successful
 338  * Returns true if bundling could be performed, otherwise false
 339  */
 340 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
 341 {
 342         struct tipc_msg *bmsg;
 343         unsigned int bsz;
 344         unsigned int msz = msg_size(msg);
 345         u32 start, pad;
 346         u32 max = mtu - INT_H_SIZE;
 347
 348         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 349                 return false;
 350         if (!skb)
 351                 return false;
 352         bmsg = buf_msg(skb);
 353         bsz = msg_size(bmsg);
 354         start = align(bsz);
 355         pad = start - bsz;
 356
 357         if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
 358                 return false;
 359         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 360                 return false;
 361         if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
 362                 return false;
 363         if (unlikely(skb_tailroom(skb) < (pad + msz)))
 364                 return false;
 365         if (unlikely(max < (start + msz)))
 366                 return false;
 367         if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
 368             (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
 369                 return false;
 370
 371         skb_put(skb, pad + msz);
 372         skb_copy_to_linear_data_offset(skb, start, msg, msz);
 373         msg_set_size(bmsg, start + msz);
 374         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 375         return true;
 376 }
 377
 378 /**
 379  *  tipc_msg_extract(): extract bundled inner packet from buffer
 380  *  @skb: buffer to be extracted from.
 381  *  @iskb: extracted inner buffer, to be returned
 382  *  @pos: position in outer message of msg to be extracted.
 383  *        Returns position of next msg
 384  *  Consumes outer buffer when last packet extracted
 385  *  Returns true when when there is an extracted buffer, otherwise false
 386  */
 387 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 388 {
 389         struct tipc_msg *msg;
 390         int imsz, offset;
 391
 392         *iskb = NULL;
 393         if (unlikely(skb_linearize(skb)))
 394                 goto none;
 395
 396         msg = buf_msg(skb);
 397         offset = msg_hdr_sz(msg) + *pos;
 398         if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
 399                 goto none;
 400
 401         *iskb = skb_clone(skb, GFP_ATOMIC);
 402         if (unlikely(!*iskb))
 403                 goto none;
 404         skb_pull(*iskb, offset);
 405         imsz = msg_size(buf_msg(*iskb));
 406         skb_trim(*iskb, imsz);
 407         if (unlikely(!tipc_msg_validate(*iskb)))
 408                 goto none;
 409         *pos += align(imsz);
 410         return true;
 411 none:
 412         kfree_skb(skb);
 413         kfree_skb(*iskb);
 414         *iskb = NULL;
 415         return false;
 416 }
 417
 418 /**
 419  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 420  * @list: the buffer chain, where head is the buffer to replace/append
 421  * @skb: buffer to be created, appended to and returned in case of success
 422  * @msg: message to be appended
 423  * @mtu: max allowable size for the bundle buffer, inclusive header
 424  * @dnode: destination node for message. (Not always present in header)
 425  * Returns true if success, otherwise false
 426  */
 427 bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 428                           u32 mtu, u32 dnode)
 429 {
 430         struct sk_buff *_skb;
 431         struct tipc_msg *bmsg;
 432         u32 msz = msg_size(msg);
 433         u32 max = mtu - INT_H_SIZE;
 434
 435         if (msg_user(msg) == MSG_FRAGMENTER)
 436                 return false;
 437         if (msg_user(msg) == TUNNEL_PROTOCOL)
 438                 return false;
 439         if (msg_user(msg) == BCAST_PROTOCOL)
 440                 return false;
 441         if (msz > (max / 2))
 442                 return false;
 443
 444         _skb = tipc_buf_acquire(max);
 445         if (!_skb)
 446                 return false;
 447
 448         skb_trim(_skb, INT_H_SIZE);
 449         bmsg = buf_msg(_skb);
 450         tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 451                       INT_H_SIZE, dnode);
 452         if (msg_isdata(msg))
 453                 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
 454         else
 455                 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 456         msg_set_seqno(bmsg, msg_seqno(msg));
 457         msg_set_ack(bmsg, msg_ack(msg));
 458         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 459         tipc_msg_bundle(_skb, msg, mtu);
 460         *skb = _skb;
 461         return true;
 462 }
 463
 464 /**
 465  * tipc_msg_reverse(): swap source and destination addresses and add error code
 466  * @own_node: originating node id for reversed message
 467  * @skb:  buffer containing message to be reversed; may be replaced.
 468  * @err:  error code to be set in message, if any
 469  * Consumes buffer at failure
 470  * Returns true if success, otherwise false
 471  */
 472 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 473 {
 474         struct sk_buff *_skb = *skb;
 475         struct tipc_msg *hdr = buf_msg(_skb);
 476         struct tipc_msg ohdr;
 477         int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
 478
 479         if (skb_linearize(_skb))
 480                 goto exit;
 481         hdr = buf_msg(_skb);
 482         if (msg_dest_droppable(hdr))
 483                 goto exit;
 484         if (msg_errcode(hdr))
 485                 goto exit;
 486
 487         /* Take a copy of original header before altering message */
 488         memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
 489
 490         /* Never return SHORT header; expand by replacing buffer if necessary */
 491         if (msg_short(hdr)) {
 492                 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
 493                 if (!*skb)
 494                         goto exit;
 495                 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
 496                 kfree_skb(_skb);
 497                 _skb = *skb;
 498                 hdr = buf_msg(_skb);
 499                 memcpy(hdr, &ohdr, BASIC_H_SIZE);
 500                 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
 501         }
 502
 503         /* Now reverse the concerned fields */
 504         msg_set_errcode(hdr, err);
 505         msg_set_origport(hdr, msg_destport(&ohdr));
 506         msg_set_destport(hdr, msg_origport(&ohdr));
 507         msg_set_destnode(hdr, msg_prevnode(&ohdr));
 508         msg_set_prevnode(hdr, own_node);
 509         msg_set_orignode(hdr, own_node);
 510         msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
 511         skb_trim(_skb, msg_size(hdr));
 512         skb_orphan(_skb);
 513         return true;
 514 exit:
 515         kfree_skb(_skb);
 516         *skb = NULL;
 517         return false;
 518 }
 519
 520 /**
 521  * tipc_msg_lookup_dest(): try to find new destination for named message
 522  * @skb: the buffer containing the message.
 523  * @err: error code to be used by caller if lookup fails
 524  * Does not consume buffer
 525  * Returns true if a destination is found, false otherwise
 526  */
 527 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
 528 {
 529         struct tipc_msg *msg = buf_msg(skb);
 530         u32 dport, dnode;
 531         u32 onode = tipc_own_addr(net);
 532
 533         if (!msg_isdata(msg))
 534                 return false;
 535         if (!msg_named(msg))
 536                 return false;
 537         if (msg_errcode(msg))
 538                 return false;
 539         *err = -TIPC_ERR_NO_NAME;
 540         if (skb_linearize(skb))
 541                 return false;
 542         if (msg_reroute_cnt(msg))
 543                 return false;
 544         dnode = addr_domain(net, msg_lookup_scope(msg));
 545         dport = tipc_nametbl_translate(net, msg_nametype(msg),
 546                                        msg_nameinst(msg), &dnode);
 547         if (!dport)
 548                 return false;
 549         msg_incr_reroute_cnt(msg);
 550         if (dnode != onode)
 551                 msg_set_prevnode(msg, onode);
 552         msg_set_destnode(msg, dnode);
 553         msg_set_destport(msg, dport);
 554         *err = TIPC_OK;
 555         return true;
 556 }
 557
 558 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 559  *                         reassemble the clones into one message
 560  */
 561 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
 562 {
 563         struct sk_buff *skb;
 564         struct sk_buff *frag = NULL;
 565         struct sk_buff *head = NULL;
 566         int hdr_sz;
 567
 568         /* Copy header if single buffer */
 569         if (skb_queue_len(list) == 1) {
 570                 skb = skb_peek(list);
 571                 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 572                 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
 573         }
 574
 575         /* Clone all fragments and reassemble */
 576         skb_queue_walk(list, skb) {
 577                 frag = skb_clone(skb, GFP_ATOMIC);
 578                 if (!frag)
 579                         goto error;
 580                 frag->next = NULL;
 581                 if (tipc_buf_append(&head, &frag))
 582                         break;
 583                 if (!head)
 584                         goto error;
 585         }
 586         return frag;
 587 error:
 588         pr_warn("Failed do clone local mcast rcv buffer\n");
 589         kfree_skb(head);
 590         return NULL;
 591 }