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 mark_mt(const struct sk_buff *skb, const struct net_device *in,
  24         const struct net_device *out, const struct xt_match *match,
  25         const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
  26 {
  27         const struct xt_mark_info *info = matchinfo;
  28
  29         return ((skb->mark & info->mask) == info->mark) ^ info->invert;
  30 }
  31
  32 static bool
  33 mark_mt_check(const char *tablename, const void *entry,
  34               const struct xt_match *match, void *matchinfo,
  35               unsigned int hook_mask)
  36 {
  37         const struct xt_mark_info *minfo = matchinfo;
  38
  39         if (minfo->mark > 0xffffffff || minfo->mask > 0xffffffff) {
  40                 printk(KERN_WARNING "mark: only supports 32bit mark\n");
  41                 return false;
  42         }
  43         return true;
  44 }
  45
  46 #ifdef CONFIG_COMPAT
  47 struct compat_xt_mark_info {
  48         compat_ulong_t  mark, mask;
  49         u_int8_t        invert;
  50         u_int8_t        __pad1;
  51         u_int16_t       __pad2;
  52 };
  53
  54 static void mark_mt_compat_from_user(void *dst, void *src)
  55 {
  56         const struct compat_xt_mark_info *cm = src;
  57         struct xt_mark_info m = {
  58                 .mark   = cm->mark,
  59                 .mask   = cm->mask,
  60                 .invert = cm->invert,
  61         };
  62         memcpy(dst, &m, sizeof(m));
  63 }
  64
  65 static int mark_mt_compat_to_user(void __user *dst, void *src)
  66 {
  67         const struct xt_mark_info *m = src;
  68         struct compat_xt_mark_info cm = {
  69                 .mark   = m->mark,
  70                 .mask   = m->mask,
  71                 .invert = m->invert,
  72         };
  73         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
  74 }
  75 #endif /* CONFIG_COMPAT */
  76
  77 static struct xt_match mark_mt_reg[] __read_mostly = {
  78         {
  79                 .name           = "mark",
  80                 .family         = AF_INET,
  81                 .checkentry     = mark_mt_check,
  82                 .match          = mark_mt,
  83                 .matchsize      = sizeof(struct xt_mark_info),
  84 #ifdef CONFIG_COMPAT
  85                 .compatsize     = sizeof(struct compat_xt_mark_info),
  86                 .compat_from_user = mark_mt_compat_from_user,
  87                 .compat_to_user = mark_mt_compat_to_user,
  88 #endif
  89                 .me             = THIS_MODULE,
  90         },
  91         {
  92                 .name           = "mark",
  93                 .family         = AF_INET6,
  94                 .checkentry     = mark_mt_check,
  95                 .match          = mark_mt,
  96                 .matchsize      = sizeof(struct xt_mark_info),
  97 #ifdef CONFIG_COMPAT
  98                 .compatsize     = sizeof(struct compat_xt_mark_info),
  99                 .compat_from_user = mark_mt_compat_from_user,
 100                 .compat_to_user = mark_mt_compat_to_user,
 101 #endif
 102                 .me             = THIS_MODULE,
 103         },
 104 };
 105
 106 static int __init mark_mt_init(void)
 107 {
 108         return xt_register_matches(mark_mt_reg, ARRAY_SIZE(mark_mt_reg));
 109 }
 110
 111 static void __exit mark_mt_exit(void)
 112 {
 113         xt_unregister_matches(mark_mt_reg, ARRAY_SIZE(mark_mt_reg));
 114 }
 115
 116 module_init(mark_mt_init);
 117 module_exit(mark_mt_exit);