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 "core.h"
  38 #include "msg.h"
  39 #include "addr.h"
  40 #include "name_table.h"
  41
  42 #define MAX_FORWARD_SIZE 1024
  43
  44 static unsigned int align(unsigned int i)
  45 {
  46         return (i + 3) & ~3u;
  47 }
  48
  49 /**
  50  * tipc_buf_acquire - creates a TIPC message buffer
  51  * @size: message size (including TIPC header)
  52  *
  53  * Returns a new buffer with data pointers set to the specified size.
  54  *
  55  * NOTE: Headroom is reserved to allow prepending of a data link header.
  56  *       There may also be unrequested tailroom present at the buffer's end.
  57  */
  58 struct sk_buff *tipc_buf_acquire(u32 size)
  59 {
  60         struct sk_buff *skb;
  61         unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
  62
  63         skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
  64         if (skb) {
  65                 skb_reserve(skb, BUF_HEADROOM);
  66                 skb_put(skb, size);
  67                 skb->next = NULL;
  68         }
  69         return skb;
  70 }
  71
  72 void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type, u32 hsize,
  73                    u32 destnode)
  74 {
  75         memset(m, 0, hsize);
  76         msg_set_version(m);
  77         msg_set_user(m, user);
  78         msg_set_hdr_sz(m, hsize);
  79         msg_set_size(m, hsize);
  80         msg_set_prevnode(m, tipc_own_addr);
  81         msg_set_type(m, type);
  82         if (hsize > SHORT_H_SIZE) {
  83                 msg_set_orignode(m, tipc_own_addr);
  84                 msg_set_destnode(m, destnode);
  85         }
  86 }
  87
  88 struct sk_buff *tipc_msg_create(uint user, uint type, uint hdr_sz,
  89                                 uint data_sz, u32 dnode, u32 onode,
  90                                 u32 dport, u32 oport, int errcode)
  91 {
  92         struct tipc_msg *msg;
  93         struct sk_buff *buf;
  94
  95         buf = tipc_buf_acquire(hdr_sz + data_sz);
  96         if (unlikely(!buf))
  97                 return NULL;
  98
  99         msg = buf_msg(buf);
 100         tipc_msg_init(msg, user, type, hdr_sz, dnode);
 101         msg_set_size(msg, hdr_sz + data_sz);
 102         msg_set_prevnode(msg, onode);
 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  * @offset: Posision in iov to start copying from
 190  * @dsz: Total length of user data
 191  * @pktmax: Max packet size that can be used
 192  * @list: Buffer or chain of buffers to be returned to caller
 193  *
 194  * Returns message data size or errno: -ENOMEM, -EFAULT
 195  */
 196 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
 197                    int dsz, int pktmax, struct sk_buff_head *list)
 198 {
 199         int mhsz = msg_hdr_sz(mhdr);
 200         int msz = mhsz + dsz;
 201         int pktno = 1;
 202         int pktsz;
 203         int pktrem = pktmax;
 204         int drem = dsz;
 205         struct tipc_msg pkthdr;
 206         struct sk_buff *skb;
 207         char *pktpos;
 208         int rc;
 209
 210         msg_set_size(mhdr, msz);
 211
 212         /* No fragmentation needed? */
 213         if (likely(msz <= pktmax)) {
 214                 skb = tipc_buf_acquire(msz);
 215                 if (unlikely(!skb))
 216                         return -ENOMEM;
 217                 __skb_queue_tail(list, skb);
 218                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 219                 pktpos = skb->data + mhsz;
 220                 if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
 221                                                  dsz))
 222                         return dsz;
 223                 rc = -EFAULT;
 224                 goto error;
 225         }
 226
 227         /* Prepare reusable fragment header */
 228         tipc_msg_init(&pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
 229                       INT_H_SIZE, msg_destnode(mhdr));
 230         msg_set_size(&pkthdr, pktmax);
 231         msg_set_fragm_no(&pkthdr, pktno);
 232
 233         /* Prepare first fragment */
 234         skb = tipc_buf_acquire(pktmax);
 235         if (!skb)
 236                 return -ENOMEM;
 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 (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
 251                         rc = -EFAULT;
 252                         goto error;
 253                 }
 254                 drem -= pktrem;
 255                 offset += pktrem;
 256
 257                 if (!drem)
 258                         break;
 259
 260                 /* Prepare new fragment: */
 261                 if (drem < (pktmax - INT_H_SIZE))
 262                         pktsz = drem + INT_H_SIZE;
 263                 else
 264                         pktsz = pktmax;
 265                 skb = tipc_buf_acquire(pktsz);
 266                 if (!skb) {
 267                         rc = -ENOMEM;
 268                         goto error;
 269                 }
 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_make_bundle(): Create bundle buf and append message to its tail
 331  * @list: the buffer chain
 332  * @skb: buffer to be appended and replaced
 333  * @mtu: max allowable size for the bundle buffer, inclusive header
 334  * @dnode: destination node for message. (Not always present in header)
 335  * Replaces buffer if successful
 336  * Returns true if success, otherwise false
 337  */
 338 bool tipc_msg_make_bundle(struct sk_buff_head *list, struct sk_buff *skb,
 339                           u32 mtu, u32 dnode)
 340 {
 341         struct sk_buff *bskb;
 342         struct tipc_msg *bmsg;
 343         struct tipc_msg *msg = buf_msg(skb);
 344         u32 msz = msg_size(msg);
 345         u32 max = mtu - INT_H_SIZE;
 346
 347         if (msg_user(msg) == MSG_FRAGMENTER)
 348                 return false;
 349         if (msg_user(msg) == CHANGEOVER_PROTOCOL)
 350                 return false;
 351         if (msg_user(msg) == BCAST_PROTOCOL)
 352                 return false;
 353         if (msz > (max / 2))
 354                 return false;
 355
 356         bskb = tipc_buf_acquire(max);
 357         if (!bskb)
 358                 return false;
 359
 360         skb_trim(bskb, INT_H_SIZE);
 361         bmsg = buf_msg(bskb);
 362         tipc_msg_init(bmsg, MSG_BUNDLER, 0, INT_H_SIZE, dnode);
 363         msg_set_seqno(bmsg, msg_seqno(msg));
 364         msg_set_ack(bmsg, msg_ack(msg));
 365         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 366         TIPC_SKB_CB(bskb)->bundling = true;
 367         __skb_queue_tail(list, bskb);
 368         return tipc_msg_bundle(list, skb, mtu);
 369 }
 370
 371 /**
 372  * tipc_msg_reverse(): swap source and destination addresses and add error code
 373  * @buf:  buffer containing message to be reversed
 374  * @dnode: return value: node where to send message after reversal
 375  * @err:  error code to be set in message
 376  * Consumes buffer if failure
 377  * Returns true if success, otherwise false
 378  */
 379 bool tipc_msg_reverse(struct sk_buff *buf, u32 *dnode, int err)
 380 {
 381         struct tipc_msg *msg = buf_msg(buf);
 382         uint imp = msg_importance(msg);
 383         struct tipc_msg ohdr;
 384         uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
 385
 386         if (skb_linearize(buf))
 387                 goto exit;
 388         if (msg_dest_droppable(msg))
 389                 goto exit;
 390         if (msg_errcode(msg))
 391                 goto exit;
 392
 393         memcpy(&ohdr, msg, msg_hdr_sz(msg));
 394         imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
 395         if (msg_isdata(msg))
 396                 msg_set_importance(msg, imp);
 397         msg_set_errcode(msg, err);
 398         msg_set_origport(msg, msg_destport(&ohdr));
 399         msg_set_destport(msg, msg_origport(&ohdr));
 400         msg_set_prevnode(msg, tipc_own_addr);
 401         if (!msg_short(msg)) {
 402                 msg_set_orignode(msg, msg_destnode(&ohdr));
 403                 msg_set_destnode(msg, msg_orignode(&ohdr));
 404         }
 405         msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
 406         skb_trim(buf, msg_size(msg));
 407         skb_orphan(buf);
 408         *dnode = msg_orignode(&ohdr);
 409         return true;
 410 exit:
 411         kfree_skb(buf);
 412         return false;
 413 }
 414
 415 /**
 416  * tipc_msg_eval: determine fate of message that found no destination
 417  * @buf: the buffer containing the message.
 418  * @dnode: return value: next-hop node, if message to be forwarded
 419  * @err: error code to use, if message to be rejected
 420  *
 421  * Does not consume buffer
 422  * Returns 0 (TIPC_OK) if message ok and we can try again, -TIPC error
 423  * code if message to be rejected
 424  */
 425 int tipc_msg_eval(struct sk_buff *buf, u32 *dnode)
 426 {
 427         struct tipc_msg *msg = buf_msg(buf);
 428         u32 dport;
 429
 430         if (msg_type(msg) != TIPC_NAMED_MSG)
 431                 return -TIPC_ERR_NO_PORT;
 432         if (skb_linearize(buf))
 433                 return -TIPC_ERR_NO_NAME;
 434         if (msg_data_sz(msg) > MAX_FORWARD_SIZE)
 435                 return -TIPC_ERR_NO_NAME;
 436         if (msg_reroute_cnt(msg) > 0)
 437                 return -TIPC_ERR_NO_NAME;
 438
 439         *dnode = addr_domain(msg_lookup_scope(msg));
 440         dport = tipc_nametbl_translate(msg_nametype(msg),
 441                                        msg_nameinst(msg),
 442                                        dnode);
 443         if (!dport)
 444                 return -TIPC_ERR_NO_NAME;
 445         msg_incr_reroute_cnt(msg);
 446         msg_set_destnode(msg, *dnode);
 447         msg_set_destport(msg, dport);
 448         return TIPC_OK;
 449 }
 450
 451 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 452  *                         reassemble the clones into one message
 453  */
 454 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
 455 {
 456         struct sk_buff *skb;
 457         struct sk_buff *frag = NULL;
 458         struct sk_buff *head = NULL;
 459         int hdr_sz;
 460
 461         /* Copy header if single buffer */
 462         if (skb_queue_len(list) == 1) {
 463                 skb = skb_peek(list);
 464                 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 465                 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
 466         }
 467
 468         /* Clone all fragments and reassemble */
 469         skb_queue_walk(list, skb) {
 470                 frag = skb_clone(skb, GFP_ATOMIC);
 471                 if (!frag)
 472                         goto error;
 473                 frag->next = NULL;
 474                 if (tipc_buf_append(&head, &frag))
 475                         break;
 476                 if (!head)
 477                         goto error;
 478         }
 479         return frag;
 480 error:
 481         pr_warn("Failed do clone local mcast rcv buffer\n");
 482         kfree_skb(head);
 483         return NULL;
 484 }