net/tipc/msg.c

   1 /*
   2  * net/tipc/msg.c: TIPC message header routines
   3  *
   4  * Copyright (c) 2000-2006, 2014, 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                 *buf = head;
 169                 TIPC_SKB_CB(head)->tail = NULL;
 170                 *headbuf = NULL;
 171                 return 1;
 172         }
 173         *buf = NULL;
 174         return 0;
 175
 176 err:
 177         pr_warn_ratelimited("Unable to build fragment list\n");
 178         kfree_skb(*buf);
 179         kfree_skb(*headbuf);
 180         *buf = *headbuf = NULL;
 181         return 0;
 182 }
 183
 184
 185 /**
 186  * tipc_msg_build - create buffer chain containing specified header and data
 187  * @mhdr: Message header, to be prepended to data
 188  * @m: User message
 189  * @dsz: Total length of user data
 190  * @pktmax: Max packet size that can be used
 191  * @list: Buffer or chain of buffers to be returned to caller
 192  *
 193  * Returns message data size or errno: -ENOMEM, -EFAULT
 194  */
 195 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 196                    int offset, int dsz, int pktmax, struct sk_buff_head *list)
 197 {
 198         int mhsz = msg_hdr_sz(mhdr);
 199         int msz = mhsz + dsz;
 200         int pktno = 1;
 201         int pktsz;
 202         int pktrem = pktmax;
 203         int drem = dsz;
 204         struct tipc_msg pkthdr;
 205         struct sk_buff *skb;
 206         char *pktpos;
 207         int rc;
 208
 209         msg_set_size(mhdr, msz);
 210
 211         /* No fragmentation needed? */
 212         if (likely(msz <= pktmax)) {
 213                 skb = tipc_buf_acquire(msz);
 214                 if (unlikely(!skb))
 215                         return -ENOMEM;
 216                 skb_orphan(skb);
 217                 __skb_queue_tail(list, skb);
 218                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 219                 pktpos = skb->data + mhsz;
 220                 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
 221                         return dsz;
 222                 rc = -EFAULT;
 223                 goto error;
 224         }
 225
 226         /* Prepare reusable fragment header */
 227         tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 228                       FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 229         msg_set_size(&pkthdr, pktmax);
 230         msg_set_fragm_no(&pkthdr, pktno);
 231
 232         /* Prepare first fragment */
 233         skb = tipc_buf_acquire(pktmax);
 234         if (!skb)
 235                 return -ENOMEM;
 236         skb_orphan(skb);
 237         __skb_queue_tail(list, skb);
 238         pktpos = skb->data;
 239         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 240         pktpos += INT_H_SIZE;
 241         pktrem -= INT_H_SIZE;
 242         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 243         pktpos += mhsz;
 244         pktrem -= mhsz;
 245
 246         do {
 247                 if (drem < pktrem)
 248                         pktrem = drem;
 249
 250                 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
 251                         rc = -EFAULT;
 252                         goto error;
 253                 }
 254                 drem -= pktrem;
 255
 256                 if (!drem)
 257                         break;
 258
 259                 /* Prepare new fragment: */
 260                 if (drem < (pktmax - INT_H_SIZE))
 261                         pktsz = drem + INT_H_SIZE;
 262                 else
 263                         pktsz = pktmax;
 264                 skb = tipc_buf_acquire(pktsz);
 265                 if (!skb) {
 266                         rc = -ENOMEM;
 267                         goto error;
 268                 }
 269                 skb_orphan(skb);
 270                 __skb_queue_tail(list, skb);
 271                 msg_set_type(&pkthdr, FRAGMENT);
 272                 msg_set_size(&pkthdr, pktsz);
 273                 msg_set_fragm_no(&pkthdr, ++pktno);
 274                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 275                 pktpos = skb->data + INT_H_SIZE;
 276                 pktrem = pktsz - INT_H_SIZE;
 277
 278         } while (1);
 279         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 280         return dsz;
 281 error:
 282         __skb_queue_purge(list);
 283         __skb_queue_head_init(list);
 284         return rc;
 285 }
 286
 287 /**
 288  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 289  * @list: the buffer chain of the existing buffer ("bundle")
 290  * @skb:  buffer to be appended
 291  * @mtu:  max allowable size for the bundle buffer
 292  * Consumes buffer if successful
 293  * Returns true if bundling could be performed, otherwise false
 294  */
 295 bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
 296 {
 297         struct sk_buff *bskb = skb_peek_tail(list);
 298         struct tipc_msg *bmsg = buf_msg(bskb);
 299         struct tipc_msg *msg = buf_msg(skb);
 300         unsigned int bsz = msg_size(bmsg);
 301         unsigned int msz = msg_size(msg);
 302         u32 start = align(bsz);
 303         u32 max = mtu - INT_H_SIZE;
 304         u32 pad = start - bsz;
 305
 306         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 307                 return false;
 308         if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
 309                 return false;
 310         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 311                 return false;
 312         if (likely(msg_user(bmsg) != MSG_BUNDLER))
 313                 return false;
 314         if (likely(!TIPC_SKB_CB(bskb)->bundling))
 315                 return false;
 316         if (unlikely(skb_tailroom(bskb) < (pad + msz)))
 317                 return false;
 318         if (unlikely(max < (start + msz)))
 319                 return false;
 320
 321         skb_put(bskb, pad + msz);
 322         skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
 323         msg_set_size(bmsg, start + msz);
 324         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 325         kfree_skb(skb);
 326         return true;
 327 }
 328
 329 /**
 330  *  tipc_msg_extract(): extract bundled inner packet from buffer
 331  *  @skb: linear outer buffer, to be extracted from.
 332  *  @iskb: extracted inner buffer, to be returned
 333  *  @pos: position of msg to be extracted. Returns with pointer of next msg
 334  *  Consumes outer buffer when last packet extracted
 335  *  Returns true when when there is an extracted buffer, otherwise false
 336  */
 337 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 338 {
 339         struct tipc_msg *msg = buf_msg(skb);
 340         int imsz;
 341         struct tipc_msg *imsg = (struct tipc_msg *)(msg_data(msg) + *pos);
 342
 343         /* Is there space left for shortest possible message? */
 344         if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE))
 345                 goto none;
 346         imsz = msg_size(imsg);
 347
 348         /* Is there space left for current message ? */
 349         if ((*pos + imsz) > msg_data_sz(msg))
 350                 goto none;
 351         *iskb = tipc_buf_acquire(imsz);
 352         if (!*iskb)
 353                 goto none;
 354         skb_copy_to_linear_data(*iskb, imsg, imsz);
 355         *pos += align(imsz);
 356         return true;
 357 none:
 358         kfree_skb(skb);
 359         *iskb = NULL;
 360         return false;
 361 }
 362
 363 /**
 364  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 365  * @list: the buffer chain
 366  * @skb: buffer to be appended and replaced
 367  * @mtu: max allowable size for the bundle buffer, inclusive header
 368  * @dnode: destination node for message. (Not always present in header)
 369  * Replaces buffer if successful
 370  * Returns true if success, otherwise false
 371  */
 372 bool tipc_msg_make_bundle(struct sk_buff_head *list,
 373                           struct sk_buff *skb, u32 mtu, u32 dnode)
 374 {
 375         struct sk_buff *bskb;
 376         struct tipc_msg *bmsg;
 377         struct tipc_msg *msg = buf_msg(skb);
 378         u32 msz = msg_size(msg);
 379         u32 max = mtu - INT_H_SIZE;
 380
 381         if (msg_user(msg) == MSG_FRAGMENTER)
 382                 return false;
 383         if (msg_user(msg) == CHANGEOVER_PROTOCOL)
 384                 return false;
 385         if (msg_user(msg) == BCAST_PROTOCOL)
 386                 return false;
 387         if (msz > (max / 2))
 388                 return false;
 389
 390         bskb = tipc_buf_acquire(max);
 391         if (!bskb)
 392                 return false;
 393
 394         skb_trim(bskb, INT_H_SIZE);
 395         bmsg = buf_msg(bskb);
 396         tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 397                       INT_H_SIZE, dnode);
 398         msg_set_seqno(bmsg, msg_seqno(msg));
 399         msg_set_ack(bmsg, msg_ack(msg));
 400         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 401         TIPC_SKB_CB(bskb)->bundling = true;
 402         __skb_queue_tail(list, bskb);
 403         return tipc_msg_bundle(list, skb, mtu);
 404 }
 405
 406 /**
 407  * tipc_msg_reverse(): swap source and destination addresses and add error code
 408  * @buf:  buffer containing message to be reversed
 409  * @dnode: return value: node where to send message after reversal
 410  * @err:  error code to be set in message
 411  * Consumes buffer if failure
 412  * Returns true if success, otherwise false
 413  */
 414 bool tipc_msg_reverse(u32 own_addr,  struct sk_buff *buf, u32 *dnode,
 415                       int err)
 416 {
 417         struct tipc_msg *msg = buf_msg(buf);
 418         uint imp = msg_importance(msg);
 419         struct tipc_msg ohdr;
 420         uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
 421
 422         if (skb_linearize(buf))
 423                 goto exit;
 424         if (msg_dest_droppable(msg))
 425                 goto exit;
 426         if (msg_errcode(msg))
 427                 goto exit;
 428
 429         memcpy(&ohdr, msg, msg_hdr_sz(msg));
 430         imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
 431         if (msg_isdata(msg))
 432                 msg_set_importance(msg, imp);
 433         msg_set_errcode(msg, err);
 434         msg_set_origport(msg, msg_destport(&ohdr));
 435         msg_set_destport(msg, msg_origport(&ohdr));
 436         msg_set_prevnode(msg, own_addr);
 437         if (!msg_short(msg)) {
 438                 msg_set_orignode(msg, msg_destnode(&ohdr));
 439                 msg_set_destnode(msg, msg_orignode(&ohdr));
 440         }
 441         msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
 442         skb_trim(buf, msg_size(msg));
 443         skb_orphan(buf);
 444         *dnode = msg_orignode(&ohdr);
 445         return true;
 446 exit:
 447         kfree_skb(buf);
 448         *dnode = 0;
 449         return false;
 450 }
 451
 452 /**
 453  * tipc_msg_lookup_dest(): try to find new destination for named message
 454  * @skb: the buffer containing the message.
 455  * @dnode: return value: next-hop node, if destination found
 456  * @err: return value: error code to use, if message to be rejected
 457  * Does not consume buffer
 458  * Returns true if a destination is found, false otherwise
 459  */
 460 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb,
 461                           u32 *dnode, int *err)
 462 {
 463         struct tipc_msg *msg = buf_msg(skb);
 464         u32 dport;
 465
 466         if (!msg_isdata(msg))
 467                 return false;
 468         if (!msg_named(msg))
 469                 return false;
 470         *err = -TIPC_ERR_NO_NAME;
 471         if (skb_linearize(skb))
 472                 return false;
 473         if (msg_reroute_cnt(msg) > 0)
 474                 return false;
 475         *dnode = addr_domain(net, msg_lookup_scope(msg));
 476         dport = tipc_nametbl_translate(net, msg_nametype(msg),
 477                                        msg_nameinst(msg), dnode);
 478         if (!dport)
 479                 return false;
 480         msg_incr_reroute_cnt(msg);
 481         msg_set_destnode(msg, *dnode);
 482         msg_set_destport(msg, dport);
 483         *err = TIPC_OK;
 484         return true;
 485 }
 486
 487 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 488  *                         reassemble the clones into one message
 489  */
 490 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
 491 {
 492         struct sk_buff *skb;
 493         struct sk_buff *frag = NULL;
 494         struct sk_buff *head = NULL;
 495         int hdr_sz;
 496
 497         /* Copy header if single buffer */
 498         if (skb_queue_len(list) == 1) {
 499                 skb = skb_peek(list);
 500                 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 501                 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
 502         }
 503
 504         /* Clone all fragments and reassemble */
 505         skb_queue_walk(list, skb) {
 506                 frag = skb_clone(skb, GFP_ATOMIC);
 507                 if (!frag)
 508                         goto error;
 509                 frag->next = NULL;
 510                 if (tipc_buf_append(&head, &frag))
 511                         break;
 512                 if (!head)
 513                         goto error;
 514         }
 515         return frag;
 516 error:
 517         pr_warn("Failed do clone local mcast rcv buffer\n");
 518         kfree_skb(head);
 519         return NULL;
 520 }