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 u32 tipc_msg_tot_importance(struct tipc_msg *m)
  41 {
  42         if (likely(msg_isdata(m))) {
  43                 if (likely(msg_orignode(m) == tipc_own_addr))
  44                         return msg_importance(m);
  45                 return msg_importance(m) + 4;
  46         }
  47         if ((msg_user(m) == MSG_FRAGMENTER)  &&
  48             (msg_type(m) == FIRST_FRAGMENT))
  49                 return msg_importance(msg_get_wrapped(m));
  50         return msg_importance(m);
  51 }
  52
  53
  54 void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type, u32 hsize,
  55                    u32 destnode)
  56 {
  57         memset(m, 0, hsize);
  58         msg_set_version(m);
  59         msg_set_user(m, user);
  60         msg_set_hdr_sz(m, hsize);
  61         msg_set_size(m, hsize);
  62         msg_set_prevnode(m, tipc_own_addr);
  63         msg_set_type(m, type);
  64         msg_set_orignode(m, tipc_own_addr);
  65         msg_set_destnode(m, destnode);
  66 }
  67
  68 /**
  69  * tipc_msg_build - create message using specified header and data
  70  *
  71  * Note: Caller must not hold any locks in case copy_from_user() is interrupted!
  72  *
  73  * Returns message data size or errno
  74  */
  75 int tipc_msg_build(struct tipc_msg *hdr, struct iovec const *msg_sect,
  76                    unsigned int len, int max_size, struct sk_buff **buf)
  77 {
  78         int dsz, sz, hsz;
  79         unsigned char *to;
  80
  81         dsz = len;
  82         hsz = msg_hdr_sz(hdr);
  83         sz = hsz + dsz;
  84         msg_set_size(hdr, sz);
  85         if (unlikely(sz > max_size)) {
  86                 *buf = NULL;
  87                 return dsz;
  88         }
  89
  90         *buf = tipc_buf_acquire(sz);
  91         if (!(*buf))
  92                 return -ENOMEM;
  93         skb_copy_to_linear_data(*buf, hdr, hsz);
  94         to = (*buf)->data + hsz;
  95         if (len && memcpy_fromiovecend(to, msg_sect, 0, dsz)) {
  96                 kfree_skb(*buf);
  97                 *buf = NULL;
  98                 return -EFAULT;
  99         }
 100         return dsz;
 101 }
 102
 103 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
 104  * Let first buffer become head buffer
 105  * Returns 1 and sets *buf to headbuf if chain is complete, otherwise 0
 106  * Leaves headbuf pointer at NULL if failure
 107  */
 108 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 109 {
 110         struct sk_buff *head = *headbuf;
 111         struct sk_buff *frag = *buf;
 112         struct sk_buff *tail;
 113         struct tipc_msg *msg = buf_msg(frag);
 114         u32 fragid = msg_type(msg);
 115         bool headstolen;
 116         int delta;
 117
 118         skb_pull(frag, msg_hdr_sz(msg));
 119
 120         if (fragid == FIRST_FRAGMENT) {
 121                 if (head || skb_unclone(frag, GFP_ATOMIC))
 122                         goto out_free;
 123                 head = *headbuf = frag;
 124                 skb_frag_list_init(head);
 125                 return 0;
 126         }
 127         if (!head)
 128                 goto out_free;
 129         tail = TIPC_SKB_CB(head)->tail;
 130         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 131                 kfree_skb_partial(frag, headstolen);
 132         } else {
 133                 if (!skb_has_frag_list(head))
 134                         skb_shinfo(head)->frag_list = frag;
 135                 else
 136                         tail->next = frag;
 137                 head->truesize += frag->truesize;
 138                 head->data_len += frag->len;
 139                 head->len += frag->len;
 140                 TIPC_SKB_CB(head)->tail = frag;
 141         }
 142         if (fragid == LAST_FRAGMENT) {
 143                 *buf = head;
 144                 TIPC_SKB_CB(head)->tail = NULL;
 145                 *headbuf = NULL;
 146                 return 1;
 147         }
 148         *buf = NULL;
 149         return 0;
 150 out_free:
 151         pr_warn_ratelimited("Unable to build fragment list\n");
 152         kfree_skb(*buf);
 153         return 0;
 154 }