net/netfilter/xt_mark.c

   1 /* Kernel module to match NFMARK values. */
   2
   3 /* (C) 1999-2001 Marc Boucher <marc@mbsi.ca>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12
  13 #include <linux/netfilter/xt_mark.h>
  14 #include <linux/netfilter/x_tables.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  18 MODULE_DESCRIPTION("iptables mark matching module");
  19 MODULE_ALIAS("ipt_mark");
  20 MODULE_ALIAS("ip6t_mark");
  21
  22 static bool
  23 match(const struct sk_buff *skb,
  24       const struct net_device *in,
  25       const struct net_device *out,
  26       const struct xt_match *match,
  27       const void *matchinfo,
  28       int offset,
  29       unsigned int protoff,
  30       bool *hotdrop)
  31 {
  32         const struct xt_mark_info *info = matchinfo;
  33
  34         return ((skb->mark & info->mask) == info->mark) ^ info->invert;
  35 }
  36
  37 static bool
  38 checkentry(const char *tablename,
  39            const void *entry,
  40            const struct xt_match *match,
  41            void *matchinfo,
  42            unsigned int hook_mask)
  43 {
  44         const struct xt_mark_info *minfo = matchinfo;
  45
  46         if (minfo->mark > 0xffffffff || minfo->mask > 0xffffffff) {
  47                 printk(KERN_WARNING "mark: only supports 32bit mark\n");
  48                 return false;
  49         }
  50         return true;
  51 }
  52
  53 #ifdef CONFIG_COMPAT
  54 struct compat_xt_mark_info {
  55         compat_ulong_t  mark, mask;
  56         u_int8_t        invert;
  57         u_int8_t        __pad1;
  58         u_int16_t       __pad2;
  59 };
  60
  61 static void compat_from_user(void *dst, void *src)
  62 {
  63         const struct compat_xt_mark_info *cm = src;
  64         struct xt_mark_info m = {
  65                 .mark   = cm->mark,
  66                 .mask   = cm->mask,
  67                 .invert = cm->invert,
  68         };
  69         memcpy(dst, &m, sizeof(m));
  70 }
  71
  72 static int compat_to_user(void __user *dst, void *src)
  73 {
  74         const struct xt_mark_info *m = src;
  75         struct compat_xt_mark_info cm = {
  76                 .mark   = m->mark,
  77                 .mask   = m->mask,
  78                 .invert = m->invert,
  79         };
  80         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
  81 }
  82 #endif /* CONFIG_COMPAT */
  83
  84 static struct xt_match xt_mark_match[] __read_mostly = {
  85         {
  86                 .name           = "mark",
  87                 .family         = AF_INET,
  88                 .checkentry     = checkentry,
  89                 .match          = match,
  90                 .matchsize      = sizeof(struct xt_mark_info),
  91 #ifdef CONFIG_COMPAT
  92                 .compatsize     = sizeof(struct compat_xt_mark_info),
  93                 .compat_from_user = compat_from_user,
  94                 .compat_to_user = compat_to_user,
  95 #endif
  96                 .me             = THIS_MODULE,
  97         },
  98         {
  99                 .name           = "mark",
 100                 .family         = AF_INET6,
 101                 .checkentry     = checkentry,
 102                 .match          = match,
 103                 .matchsize      = sizeof(struct xt_mark_info),
 104                 .me             = THIS_MODULE,
 105         },
 106 };
 107
 108 static int __init xt_mark_init(void)
 109 {
 110         return xt_register_matches(xt_mark_match, ARRAY_SIZE(xt_mark_match));
 111 }
 112
 113 static void __exit xt_mark_fini(void)
 114 {
 115         xt_unregister_matches(xt_mark_match, ARRAY_SIZE(xt_mark_match));
 116 }
 117
 118 module_init(xt_mark_init);
 119 module_exit(xt_mark_fini);