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
  40 static unsigned int align(unsigned int i)
  41 {
  42         return (i + 3) & ~3u;
  43 }
  44
  45 void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type, u32 hsize,
  46                    u32 destnode)
  47 {
  48         memset(m, 0, hsize);
  49         msg_set_version(m);
  50         msg_set_user(m, user);
  51         msg_set_hdr_sz(m, hsize);
  52         msg_set_size(m, hsize);
  53         msg_set_prevnode(m, tipc_own_addr);
  54         msg_set_type(m, type);
  55         msg_set_orignode(m, tipc_own_addr);
  56         msg_set_destnode(m, destnode);
  57 }
  58
  59 /**
  60  * tipc_msg_build - create message using specified header and data
  61  *
  62  * Note: Caller must not hold any locks in case copy_from_user() is interrupted!
  63  *
  64  * Returns message data size or errno
  65  */
  66 int tipc_msg_build(struct tipc_msg *hdr, struct iovec const *msg_sect,
  67                    unsigned int len, int max_size, struct sk_buff **buf)
  68 {
  69         int dsz, sz, hsz;
  70         unsigned char *to;
  71
  72         dsz = len;
  73         hsz = msg_hdr_sz(hdr);
  74         sz = hsz + dsz;
  75         msg_set_size(hdr, sz);
  76         if (unlikely(sz > max_size)) {
  77                 *buf = NULL;
  78                 return dsz;
  79         }
  80
  81         *buf = tipc_buf_acquire(sz);
  82         if (!(*buf))
  83                 return -ENOMEM;
  84         skb_copy_to_linear_data(*buf, hdr, hsz);
  85         to = (*buf)->data + hsz;
  86         if (len && memcpy_fromiovecend(to, msg_sect, 0, dsz)) {
  87                 kfree_skb(*buf);
  88                 *buf = NULL;
  89                 return -EFAULT;
  90         }
  91         return dsz;
  92 }
  93
  94 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
  95  * Let first buffer become head buffer
  96  * Returns 1 and sets *buf to headbuf if chain is complete, otherwise 0
  97  * Leaves headbuf pointer at NULL if failure
  98  */
  99 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 100 {
 101         struct sk_buff *head = *headbuf;
 102         struct sk_buff *frag = *buf;
 103         struct sk_buff *tail;
 104         struct tipc_msg *msg = buf_msg(frag);
 105         u32 fragid = msg_type(msg);
 106         bool headstolen;
 107         int delta;
 108
 109         skb_pull(frag, msg_hdr_sz(msg));
 110
 111         if (fragid == FIRST_FRAGMENT) {
 112                 if (head || skb_unclone(frag, GFP_ATOMIC))
 113                         goto out_free;
 114                 head = *headbuf = frag;
 115                 skb_frag_list_init(head);
 116                 return 0;
 117         }
 118         if (!head)
 119                 goto out_free;
 120         tail = TIPC_SKB_CB(head)->tail;
 121         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 122                 kfree_skb_partial(frag, headstolen);
 123         } else {
 124                 if (!skb_has_frag_list(head))
 125                         skb_shinfo(head)->frag_list = frag;
 126                 else
 127                         tail->next = frag;
 128                 head->truesize += frag->truesize;
 129                 head->data_len += frag->len;
 130                 head->len += frag->len;
 131                 TIPC_SKB_CB(head)->tail = frag;
 132         }
 133         if (fragid == LAST_FRAGMENT) {
 134                 *buf = head;
 135                 TIPC_SKB_CB(head)->tail = NULL;
 136                 *headbuf = NULL;
 137                 return 1;
 138         }
 139         *buf = NULL;
 140         return 0;
 141 out_free:
 142         pr_warn_ratelimited("Unable to build fragment list\n");
 143         kfree_skb(*buf);
 144         return 0;
 145 }
 146
 147
 148 /**
 149  * tipc_msg_build2 - create buffer chain containing specified header and data
 150  * @mhdr: Message header, to be prepended to data
 151  * @iov: User data
 152  * @offset: Posision in iov to start copying from
 153  * @dsz: Total length of user data
 154  * @pktmax: Max packet size that can be used
 155  * @chain: Buffer or chain of buffers to be returned to caller
 156  * Returns message data size or errno: -ENOMEM, -EFAULT
 157  */
 158 int tipc_msg_build2(struct tipc_msg *mhdr, struct iovec const *iov,
 159                     int offset, int dsz, int pktmax , struct sk_buff **chain)
 160 {
 161         int mhsz = msg_hdr_sz(mhdr);
 162         int msz = mhsz + dsz;
 163         int pktno = 1;
 164         int pktsz;
 165         int pktrem = pktmax;
 166         int drem = dsz;
 167         struct tipc_msg pkthdr;
 168         struct sk_buff *buf, *prev;
 169         char *pktpos;
 170         int rc;
 171
 172         msg_set_size(mhdr, msz);
 173
 174         /* No fragmentation needed? */
 175         if (likely(msz <= pktmax)) {
 176                 buf = tipc_buf_acquire(msz);
 177                 *chain = buf;
 178                 if (unlikely(!buf))
 179                         return -ENOMEM;
 180                 skb_copy_to_linear_data(buf, mhdr, mhsz);
 181                 pktpos = buf->data + mhsz;
 182                 if (!dsz || !memcpy_fromiovecend(pktpos, iov, offset, dsz))
 183                         return dsz;
 184                 rc = -EFAULT;
 185                 goto error;
 186         }
 187
 188         /* Prepare reusable fragment header */
 189         tipc_msg_init(&pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
 190                       INT_H_SIZE, msg_destnode(mhdr));
 191         msg_set_size(&pkthdr, pktmax);
 192         msg_set_fragm_no(&pkthdr, pktno);
 193
 194         /* Prepare first fragment */
 195         *chain = buf = tipc_buf_acquire(pktmax);
 196         if (!buf)
 197                 return -ENOMEM;
 198         pktpos = buf->data;
 199         skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
 200         pktpos += INT_H_SIZE;
 201         pktrem -= INT_H_SIZE;
 202         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, mhdr, mhsz);
 203         pktpos += mhsz;
 204         pktrem -= mhsz;
 205
 206         do {
 207                 if (drem < pktrem)
 208                         pktrem = drem;
 209
 210                 if (memcpy_fromiovecend(pktpos, iov, offset, pktrem)) {
 211                         rc = -EFAULT;
 212                         goto error;
 213                 }
 214                 drem -= pktrem;
 215                 offset += pktrem;
 216
 217                 if (!drem)
 218                         break;
 219
 220                 /* Prepare new fragment: */
 221                 if (drem < (pktmax - INT_H_SIZE))
 222                         pktsz = drem + INT_H_SIZE;
 223                 else
 224                         pktsz = pktmax;
 225                 prev = buf;
 226                 buf = tipc_buf_acquire(pktsz);
 227                 if (!buf) {
 228                         rc = -ENOMEM;
 229                         goto error;
 230                 }
 231                 prev->next = buf;
 232                 msg_set_type(&pkthdr, FRAGMENT);
 233                 msg_set_size(&pkthdr, pktsz);
 234                 msg_set_fragm_no(&pkthdr, ++pktno);
 235                 skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
 236                 pktpos = buf->data + INT_H_SIZE;
 237                 pktrem = pktsz - INT_H_SIZE;
 238
 239         } while (1);
 240
 241         msg_set_type(buf_msg(buf), LAST_FRAGMENT);
 242         return dsz;
 243 error:
 244         kfree_skb_list(*chain);
 245         *chain = NULL;
 246         return rc;
 247 }
 248
 249 /**
 250  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 251  * @bbuf: the existing buffer ("bundle")
 252  * @buf:  buffer to be appended
 253  * @mtu:  max allowable size for the bundle buffer
 254  * Consumes buffer if successful
 255  * Returns true if bundling could be performed, otherwise false
 256  */
 257 bool tipc_msg_bundle(struct sk_buff *bbuf, struct sk_buff *buf, u32 mtu)
 258 {
 259         struct tipc_msg *bmsg = buf_msg(bbuf);
 260         struct tipc_msg *msg = buf_msg(buf);
 261         unsigned int bsz = msg_size(bmsg);
 262         unsigned int msz = msg_size(msg);
 263         u32 start = align(bsz);
 264         u32 max = mtu - INT_H_SIZE;
 265         u32 pad = start - bsz;
 266
 267         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 268                 return false;
 269         if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
 270                 return false;
 271         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 272                 return false;
 273         if (likely(msg_user(bmsg) != MSG_BUNDLER))
 274                 return false;
 275         if (likely(msg_type(bmsg) != BUNDLE_OPEN))
 276                 return false;
 277         if (unlikely(skb_tailroom(bbuf) < (pad + msz)))
 278                 return false;
 279         if (unlikely(max < (start + msz)))
 280                 return false;
 281
 282         skb_put(bbuf, pad + msz);
 283         skb_copy_to_linear_data_offset(bbuf, start, buf->data, msz);
 284         msg_set_size(bmsg, start + msz);
 285         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 286         bbuf->next = buf->next;
 287         kfree_skb(buf);
 288         return true;
 289 }
 290
 291 /**
 292  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 293  * @buf:  buffer to be appended and replaced
 294  * @mtu:  max allowable size for the bundle buffer, inclusive header
 295  * @dnode: destination node for message. (Not always present in header)
 296  * Replaces buffer if successful
 297  * Returns true if sucess, otherwise false
 298  */
 299 bool tipc_msg_make_bundle(struct sk_buff **buf, u32 mtu, u32 dnode)
 300 {
 301         struct sk_buff *bbuf;
 302         struct tipc_msg *bmsg;
 303         struct tipc_msg *msg = buf_msg(*buf);
 304         u32 msz = msg_size(msg);
 305         u32 max = mtu - INT_H_SIZE;
 306
 307         if (msg_user(msg) == MSG_FRAGMENTER)
 308                 return false;
 309         if (msg_user(msg) == CHANGEOVER_PROTOCOL)
 310                 return false;
 311         if (msg_user(msg) == BCAST_PROTOCOL)
 312                 return false;
 313         if (msz > (max / 2))
 314                 return false;
 315
 316         bbuf = tipc_buf_acquire(max);
 317         if (!bbuf)
 318                 return false;
 319
 320         skb_trim(bbuf, INT_H_SIZE);
 321         bmsg = buf_msg(bbuf);
 322         tipc_msg_init(bmsg, MSG_BUNDLER, BUNDLE_OPEN, INT_H_SIZE, dnode);
 323         msg_set_seqno(bmsg, msg_seqno(msg));
 324         msg_set_ack(bmsg, msg_ack(msg));
 325         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 326         bbuf->next = (*buf)->next;
 327         tipc_msg_bundle(bbuf, *buf, mtu);
 328         *buf = bbuf;
 329         return true;
 330 }