net/ipv4/netfilter/ipt_MARK.c

   1 /* This is a module which is used for setting the NFMARK field of an skb. */
   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 #include <linux/ip.h>
  13 #include <net/checksum.h>
  14
  15 #include <linux/netfilter_ipv4/ip_tables.h>
  16 #include <linux/netfilter_ipv4/ipt_MARK.h>
  17
  18 MODULE_LICENSE("GPL");
  19 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  20 MODULE_DESCRIPTION("iptables MARK modification module");
  21
  22 static unsigned int
  23 target_v0(struct sk_buff **pskb,
  24           const struct net_device *in,
  25           const struct net_device *out,
  26           unsigned int hooknum,
  27           const void *targinfo,
  28           void *userinfo)
  29 {
  30         const struct ipt_mark_target_info *markinfo = targinfo;
  31
  32         if((*pskb)->nfmark != markinfo->mark) {
  33                 (*pskb)->nfmark = markinfo->mark;
  34                 (*pskb)->nfcache |= NFC_ALTERED;
  35         }
  36         return IPT_CONTINUE;
  37 }
  38
  39 static unsigned int
  40 target_v1(struct sk_buff **pskb,
  41           const struct net_device *in,
  42           const struct net_device *out,
  43           unsigned int hooknum,
  44           const void *targinfo,
  45           void *userinfo)
  46 {
  47         const struct ipt_mark_target_info_v1 *markinfo = targinfo;
  48         int mark = 0;
  49
  50         switch (markinfo->mode) {
  51         case IPT_MARK_SET:
  52                 mark = markinfo->mark;
  53                 break;
  54
  55         case IPT_MARK_AND:
  56                 mark = (*pskb)->nfmark & markinfo->mark;
  57                 break;
  58
  59         case IPT_MARK_OR:
  60                 mark = (*pskb)->nfmark | markinfo->mark;
  61                 break;
  62         }
  63
  64         if((*pskb)->nfmark != mark) {
  65                 (*pskb)->nfmark = mark;
  66                 (*pskb)->nfcache |= NFC_ALTERED;
  67         }
  68         return IPT_CONTINUE;
  69 }
  70
  71
  72 static int
  73 checkentry_v0(const char *tablename,
  74               const struct ipt_entry *e,
  75               void *targinfo,
  76               unsigned int targinfosize,
  77               unsigned int hook_mask)
  78 {
  79         if (targinfosize != IPT_ALIGN(sizeof(struct ipt_mark_target_info))) {
  80                 printk(KERN_WARNING "MARK: targinfosize %u != %Zu\n",
  81                        targinfosize,
  82                        IPT_ALIGN(sizeof(struct ipt_mark_target_info)));
  83                 return 0;
  84         }
  85
  86         if (strcmp(tablename, "mangle") != 0) {
  87                 printk(KERN_WARNING "MARK: can only be called from \"mangle\" table, not \"%s\"\n", tablename);
  88                 return 0;
  89         }
  90
  91         return 1;
  92 }
  93
  94 static int
  95 checkentry_v1(const char *tablename,
  96               const struct ipt_entry *e,
  97               void *targinfo,
  98               unsigned int targinfosize,
  99               unsigned int hook_mask)
 100 {
 101         struct ipt_mark_target_info_v1 *markinfo = targinfo;
 102
 103         if (targinfosize != IPT_ALIGN(sizeof(struct ipt_mark_target_info_v1))){
 104                 printk(KERN_WARNING "MARK: targinfosize %u != %Zu\n",
 105                        targinfosize,
 106                        IPT_ALIGN(sizeof(struct ipt_mark_target_info_v1)));
 107                 return 0;
 108         }
 109
 110         if (strcmp(tablename, "mangle") != 0) {
 111                 printk(KERN_WARNING "MARK: can only be called from \"mangle\" table, not \"%s\"\n", tablename);
 112                 return 0;
 113         }
 114
 115         if (markinfo->mode != IPT_MARK_SET
 116             && markinfo->mode != IPT_MARK_AND
 117             && markinfo->mode != IPT_MARK_OR) {
 118                 printk(KERN_WARNING "MARK: unknown mode %u\n",
 119                        markinfo->mode);
 120                 return 0;
 121         }
 122
 123         return 1;
 124 }
 125
 126 static struct ipt_target ipt_mark_reg_v0 = {
 127         .name           = "MARK",
 128         .target         = target_v0,
 129         .checkentry     = checkentry_v0,
 130         .me             = THIS_MODULE,
 131         .revision       = 0,
 132 };
 133
 134 static struct ipt_target ipt_mark_reg_v1 = {
 135         .name           = "MARK",
 136         .target         = target_v1,
 137         .checkentry     = checkentry_v1,
 138         .me             = THIS_MODULE,
 139         .revision       = 1,
 140 };
 141
 142 static int __init init(void)
 143 {
 144         int err;
 145
 146         err = ipt_register_target(&ipt_mark_reg_v0);
 147         if (!err) {
 148                 err = ipt_register_target(&ipt_mark_reg_v1);
 149                 if (err)
 150                         ipt_unregister_target(&ipt_mark_reg_v0);
 151         }
 152         return err;
 153 }
 154
 155 static void __exit fini(void)
 156 {
 157         ipt_unregister_target(&ipt_mark_reg_v0);
 158         ipt_unregister_target(&ipt_mark_reg_v1);
 159 }
 160
 161 module_init(init);
 162 module_exit(fini);