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 void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type, u32 hsize,
  50                    u32 destnode)
  51 {
  52         memset(m, 0, hsize);
  53         msg_set_version(m);
  54         msg_set_user(m, user);
  55         msg_set_hdr_sz(m, hsize);
  56         msg_set_size(m, hsize);
  57         msg_set_prevnode(m, tipc_own_addr);
  58         msg_set_type(m, type);
  59         if (hsize > SHORT_H_SIZE) {
  60                 msg_set_orignode(m, tipc_own_addr);
  61                 msg_set_destnode(m, destnode);
  62         }
  63 }
  64
  65 struct sk_buff *tipc_msg_create(uint user, uint type, uint hdr_sz,
  66                                 uint data_sz, u32 dnode, u32 onode,
  67                                 u32 dport, u32 oport, int errcode)
  68 {
  69         struct tipc_msg *msg;
  70         struct sk_buff *buf;
  71
  72         buf = tipc_buf_acquire(hdr_sz + data_sz);
  73         if (unlikely(!buf))
  74                 return NULL;
  75
  76         msg = buf_msg(buf);
  77         tipc_msg_init(msg, user, type, hdr_sz, dnode);
  78         msg_set_size(msg, hdr_sz + data_sz);
  79         msg_set_prevnode(msg, onode);
  80         msg_set_origport(msg, oport);
  81         msg_set_destport(msg, dport);
  82         msg_set_errcode(msg, errcode);
  83         if (hdr_sz > SHORT_H_SIZE) {
  84                 msg_set_orignode(msg, onode);
  85                 msg_set_destnode(msg, dnode);
  86         }
  87         return buf;
  88 }
  89
  90 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
  91  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
  92  *            out: set when successful non-complete reassembly, otherwise NULL
  93  * @*buf:     in:  the buffer to append. Always defined
  94  *            out: head buf after successful complete reassembly, otherwise NULL
  95  * Returns 1 when reassembly complete, otherwise 0
  96  */
  97 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
  98 {
  99         struct sk_buff *head = *headbuf;
 100         struct sk_buff *frag = *buf;
 101         struct sk_buff *tail;
 102         struct tipc_msg *msg;
 103         u32 fragid;
 104         int delta;
 105         bool headstolen;
 106
 107         if (!frag)
 108                 goto err;
 109
 110         msg = buf_msg(frag);
 111         fragid = msg_type(msg);
 112         frag->next = NULL;
 113         skb_pull(frag, msg_hdr_sz(msg));
 114
 115         if (fragid == FIRST_FRAGMENT) {
 116                 if (unlikely(head))
 117                         goto err;
 118                 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
 119                         goto err;
 120                 head = *headbuf = frag;
 121                 skb_frag_list_init(head);
 122                 TIPC_SKB_CB(head)->tail = NULL;
 123                 *buf = NULL;
 124                 return 0;
 125         }
 126
 127         if (!head)
 128                 goto err;
 129
 130         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 131                 kfree_skb_partial(frag, headstolen);
 132         } else {
 133                 tail = TIPC_SKB_CB(head)->tail;
 134                 if (!skb_has_frag_list(head))
 135                         skb_shinfo(head)->frag_list = frag;
 136                 else
 137                         tail->next = frag;
 138                 head->truesize += frag->truesize;
 139                 head->data_len += frag->len;
 140                 head->len += frag->len;
 141                 TIPC_SKB_CB(head)->tail = frag;
 142         }
 143
 144         if (fragid == LAST_FRAGMENT) {
 145                 *buf = head;
 146                 TIPC_SKB_CB(head)->tail = NULL;
 147                 *headbuf = NULL;
 148                 return 1;
 149         }
 150         *buf = NULL;
 151         return 0;
 152
 153 err:
 154         pr_warn_ratelimited("Unable to build fragment list\n");
 155         kfree_skb(*buf);
 156         kfree_skb(*headbuf);
 157         *buf = *headbuf = NULL;
 158         return 0;
 159 }
 160
 161
 162 /**
 163  * tipc_msg_build - create buffer chain containing specified header and data
 164  * @mhdr: Message header, to be prepended to data
 165  * @m: User message
 166  * @offset: Posision in iov to start copying from
 167  * @dsz: Total length of user data
 168  * @pktmax: Max packet size that can be used
 169  * @list: Buffer or chain of buffers to be returned to caller
 170  *
 171  * Returns message data size or errno: -ENOMEM, -EFAULT
 172  */
 173 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
 174                    int dsz, int pktmax, struct sk_buff_head *list)
 175 {
 176         int mhsz = msg_hdr_sz(mhdr);
 177         int msz = mhsz + dsz;
 178         int pktno = 1;
 179         int pktsz;
 180         int pktrem = pktmax;
 181         int drem = dsz;
 182         struct tipc_msg pkthdr;
 183         struct sk_buff *skb;
 184         char *pktpos;
 185         int rc;
 186
 187         msg_set_size(mhdr, msz);
 188
 189         /* No fragmentation needed? */
 190         if (likely(msz <= pktmax)) {
 191                 skb = tipc_buf_acquire(msz);
 192                 if (unlikely(!skb))
 193                         return -ENOMEM;
 194                 __skb_queue_tail(list, skb);
 195                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 196                 pktpos = skb->data + mhsz;
 197                 if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
 198                                                  dsz))
 199                         return dsz;
 200                 rc = -EFAULT;
 201                 goto error;
 202         }
 203
 204         /* Prepare reusable fragment header */
 205         tipc_msg_init(&pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
 206                       INT_H_SIZE, msg_destnode(mhdr));
 207         msg_set_size(&pkthdr, pktmax);
 208         msg_set_fragm_no(&pkthdr, pktno);
 209
 210         /* Prepare first fragment */
 211         skb = tipc_buf_acquire(pktmax);
 212         if (!skb)
 213                 return -ENOMEM;
 214         __skb_queue_tail(list, skb);
 215         pktpos = skb->data;
 216         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 217         pktpos += INT_H_SIZE;
 218         pktrem -= INT_H_SIZE;
 219         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 220         pktpos += mhsz;
 221         pktrem -= mhsz;
 222
 223         do {
 224                 if (drem < pktrem)
 225                         pktrem = drem;
 226
 227                 if (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
 228                         rc = -EFAULT;
 229                         goto error;
 230                 }
 231                 drem -= pktrem;
 232                 offset += pktrem;
 233
 234                 if (!drem)
 235                         break;
 236
 237                 /* Prepare new fragment: */
 238                 if (drem < (pktmax - INT_H_SIZE))
 239                         pktsz = drem + INT_H_SIZE;
 240                 else
 241                         pktsz = pktmax;
 242                 skb = tipc_buf_acquire(pktsz);
 243                 if (!skb) {
 244                         rc = -ENOMEM;
 245                         goto error;
 246                 }
 247                 __skb_queue_tail(list, skb);
 248                 msg_set_type(&pkthdr, FRAGMENT);
 249                 msg_set_size(&pkthdr, pktsz);
 250                 msg_set_fragm_no(&pkthdr, ++pktno);
 251                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 252                 pktpos = skb->data + INT_H_SIZE;
 253                 pktrem = pktsz - INT_H_SIZE;
 254
 255         } while (1);
 256         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 257         return dsz;
 258 error:
 259         __skb_queue_purge(list);
 260         __skb_queue_head_init(list);
 261         return rc;
 262 }
 263
 264 /**
 265  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 266  * @list: the buffer chain of the existing buffer ("bundle")
 267  * @skb:  buffer to be appended
 268  * @mtu:  max allowable size for the bundle buffer
 269  * Consumes buffer if successful
 270  * Returns true if bundling could be performed, otherwise false
 271  */
 272 bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
 273 {
 274         struct sk_buff *bskb = skb_peek_tail(list);
 275         struct tipc_msg *bmsg = buf_msg(bskb);
 276         struct tipc_msg *msg = buf_msg(skb);
 277         unsigned int bsz = msg_size(bmsg);
 278         unsigned int msz = msg_size(msg);
 279         u32 start = align(bsz);
 280         u32 max = mtu - INT_H_SIZE;
 281         u32 pad = start - bsz;
 282
 283         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 284                 return false;
 285         if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
 286                 return false;
 287         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 288                 return false;
 289         if (likely(msg_user(bmsg) != MSG_BUNDLER))
 290                 return false;
 291         if (likely(!TIPC_SKB_CB(bskb)->bundling))
 292                 return false;
 293         if (unlikely(skb_tailroom(bskb) < (pad + msz)))
 294                 return false;
 295         if (unlikely(max < (start + msz)))
 296                 return false;
 297
 298         skb_put(bskb, pad + msz);
 299         skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
 300         msg_set_size(bmsg, start + msz);
 301         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 302         kfree_skb(skb);
 303         return true;
 304 }
 305
 306 /**
 307  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 308  * @list: the buffer chain
 309  * @skb: buffer to be appended and replaced
 310  * @mtu: max allowable size for the bundle buffer, inclusive header
 311  * @dnode: destination node for message. (Not always present in header)
 312  * Replaces buffer if successful
 313  * Returns true if success, otherwise false
 314  */
 315 bool tipc_msg_make_bundle(struct sk_buff_head *list, struct sk_buff *skb,
 316                           u32 mtu, u32 dnode)
 317 {
 318         struct sk_buff *bskb;
 319         struct tipc_msg *bmsg;
 320         struct tipc_msg *msg = buf_msg(skb);
 321         u32 msz = msg_size(msg);
 322         u32 max = mtu - INT_H_SIZE;
 323
 324         if (msg_user(msg) == MSG_FRAGMENTER)
 325                 return false;
 326         if (msg_user(msg) == CHANGEOVER_PROTOCOL)
 327                 return false;
 328         if (msg_user(msg) == BCAST_PROTOCOL)
 329                 return false;
 330         if (msz > (max / 2))
 331                 return false;
 332
 333         bskb = tipc_buf_acquire(max);
 334         if (!bskb)
 335                 return false;
 336
 337         skb_trim(bskb, INT_H_SIZE);
 338         bmsg = buf_msg(bskb);
 339         tipc_msg_init(bmsg, MSG_BUNDLER, 0, INT_H_SIZE, dnode);
 340         msg_set_seqno(bmsg, msg_seqno(msg));
 341         msg_set_ack(bmsg, msg_ack(msg));
 342         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 343         TIPC_SKB_CB(bskb)->bundling = true;
 344         __skb_queue_tail(list, bskb);
 345         return tipc_msg_bundle(list, skb, mtu);
 346 }
 347
 348 /**
 349  * tipc_msg_reverse(): swap source and destination addresses and add error code
 350  * @buf:  buffer containing message to be reversed
 351  * @dnode: return value: node where to send message after reversal
 352  * @err:  error code to be set in message
 353  * Consumes buffer if failure
 354  * Returns true if success, otherwise false
 355  */
 356 bool tipc_msg_reverse(struct sk_buff *buf, u32 *dnode, int err)
 357 {
 358         struct tipc_msg *msg = buf_msg(buf);
 359         uint imp = msg_importance(msg);
 360         struct tipc_msg ohdr;
 361         uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
 362
 363         if (skb_linearize(buf))
 364                 goto exit;
 365         if (msg_dest_droppable(msg))
 366                 goto exit;
 367         if (msg_errcode(msg))
 368                 goto exit;
 369
 370         memcpy(&ohdr, msg, msg_hdr_sz(msg));
 371         imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
 372         if (msg_isdata(msg))
 373                 msg_set_importance(msg, imp);
 374         msg_set_errcode(msg, err);
 375         msg_set_origport(msg, msg_destport(&ohdr));
 376         msg_set_destport(msg, msg_origport(&ohdr));
 377         msg_set_prevnode(msg, tipc_own_addr);
 378         if (!msg_short(msg)) {
 379                 msg_set_orignode(msg, msg_destnode(&ohdr));
 380                 msg_set_destnode(msg, msg_orignode(&ohdr));
 381         }
 382         msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
 383         skb_trim(buf, msg_size(msg));
 384         skb_orphan(buf);
 385         *dnode = msg_orignode(&ohdr);
 386         return true;
 387 exit:
 388         kfree_skb(buf);
 389         return false;
 390 }
 391
 392 /**
 393  * tipc_msg_eval: determine fate of message that found no destination
 394  * @buf: the buffer containing the message.
 395  * @dnode: return value: next-hop node, if message to be forwarded
 396  * @err: error code to use, if message to be rejected
 397  *
 398  * Does not consume buffer
 399  * Returns 0 (TIPC_OK) if message ok and we can try again, -TIPC error
 400  * code if message to be rejected
 401  */
 402 int tipc_msg_eval(struct sk_buff *buf, u32 *dnode)
 403 {
 404         struct tipc_msg *msg = buf_msg(buf);
 405         u32 dport;
 406
 407         if (msg_type(msg) != TIPC_NAMED_MSG)
 408                 return -TIPC_ERR_NO_PORT;
 409         if (skb_linearize(buf))
 410                 return -TIPC_ERR_NO_NAME;
 411         if (msg_data_sz(msg) > MAX_FORWARD_SIZE)
 412                 return -TIPC_ERR_NO_NAME;
 413         if (msg_reroute_cnt(msg) > 0)
 414                 return -TIPC_ERR_NO_NAME;
 415
 416         *dnode = addr_domain(msg_lookup_scope(msg));
 417         dport = tipc_nametbl_translate(msg_nametype(msg),
 418                                        msg_nameinst(msg),
 419                                        dnode);
 420         if (!dport)
 421                 return -TIPC_ERR_NO_NAME;
 422         msg_incr_reroute_cnt(msg);
 423         msg_set_destnode(msg, *dnode);
 424         msg_set_destport(msg, dport);
 425         return TIPC_OK;
 426 }
 427
 428 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 429  *                         reassemble the clones into one message
 430  */
 431 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
 432 {
 433         struct sk_buff *skb;
 434         struct sk_buff *frag = NULL;
 435         struct sk_buff *head = NULL;
 436         int hdr_sz;
 437
 438         /* Copy header if single buffer */
 439         if (skb_queue_len(list) == 1) {
 440                 skb = skb_peek(list);
 441                 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 442                 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
 443         }
 444
 445         /* Clone all fragments and reassemble */
 446         skb_queue_walk(list, skb) {
 447                 frag = skb_clone(skb, GFP_ATOMIC);
 448                 if (!frag)
 449                         goto error;
 450                 frag->next = NULL;
 451                 if (tipc_buf_append(&head, &frag))
 452                         break;
 453                 if (!head)
 454                         goto error;
 455         }
 456         return frag;
 457 error:
 458         pr_warn("Failed do clone local mcast rcv buffer\n");
 459         kfree_skb(head);
 460         return NULL;
 461 }