datapath/compat.h

   1 /*
   2  * Copyright (c) 2007-2012 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #ifndef COMPAT_H
  20 #define COMPAT_H 1
  21
  22 #include <linux/netlink.h>
  23
  24 #ifndef HAVE_NLA_NUL_STRING
  25 static inline int CHECK_NUL_STRING(struct nlattr *attr, int maxlen)
  26 {
  27         char *s;
  28         int len;
  29         if (!attr)
  30                 return 0;
  31
  32         len = nla_len(attr);
  33         if (len >= maxlen)
  34                 return -EINVAL;
  35
  36         s = nla_data(attr);
  37         if (s[len - 1] != '\0')
  38                 return -EINVAL;
  39
  40         return 0;
  41 }
  42 #else
  43 static inline int CHECK_NUL_STRING(struct nlattr *attr, int maxlen)
  44 {
  45         return 0;
  46 }
  47 #endif  /* !HAVE_NLA_NUL_STRING */
  48
  49 static inline void skb_clear_rxhash(struct sk_buff *skb)
  50 {
  51 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,35)
  52         skb->rxhash = 0;
  53 #endif
  54 }
  55
  56 /*
  57  * Enforces, mutual exclusion with the Linux bridge module, by declaring and
  58  * exporting br_should_route_hook.  Because the bridge module also exports the
  59  * same symbol, the module loader will refuse to load both modules at the same
  60  * time (e.g. "bridge: exports duplicate symbol br_should_route_hook (owned by
  61  * openvswitch)").
  62  *
  63  * Before Linux 2.6.36, Open vSwitch cannot safely coexist with the Linux
  64  * bridge module, so openvswitch uses this macro in those versions.  In
  65  * Linux 2.6.36 and later, Open vSwitch can coexist with the bridge module,
  66  * but it makes no sense to load both bridge and brcompat, so brcompat uses
  67  * this macro in those versions.
  68  *
  69  * The use of "typeof" here avoids the need to track changes in the type of
  70  * br_should_route_hook over various kernel versions.
  71  */
  72 #define BRIDGE_MUTUAL_EXCLUSION                                 \
  73         typeof(br_should_route_hook) br_should_route_hook;      \
  74         EXPORT_SYMBOL(br_should_route_hook)
  75
  76 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
  77 #define GENL_SOCK(net) (genl_sock)
  78 #define SET_NETNSOK
  79 #else
  80 #define GENL_SOCK(net) ((net)->genl_sock)
  81 #define SET_NETNSOK    .netnsok = true,
  82 #endif
  83
  84 #endif /* compat.h */