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