net/ipv4/netfilter/ipt_CLASSIFY.c

   1 /*
   2  * This is a module which is used for setting the skb->priority field
   3  * of an skb for qdisc classification.
   4  */
   5
   6 /* (C) 2001-2002 Patrick McHardy <kaber@trash.net>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/ip.h>
  16 #include <net/checksum.h>
  17
  18 #include <linux/netfilter_ipv4/ip_tables.h>
  19 #include <linux/netfilter_ipv4/ipt_CLASSIFY.h>
  20
  21 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  22 MODULE_LICENSE("GPL");
  23 MODULE_DESCRIPTION("iptables qdisc classification target module");
  24
  25 static unsigned int
  26 target(struct sk_buff **pskb,
  27        const struct net_device *in,
  28        const struct net_device *out,
  29        unsigned int hooknum,
  30        const void *targinfo,
  31        void *userinfo)
  32 {
  33         const struct ipt_classify_target_info *clinfo = targinfo;
  34
  35         if((*pskb)->priority != clinfo->priority) {
  36                 (*pskb)->priority = clinfo->priority;
  37                 (*pskb)->nfcache |= NFC_ALTERED;
  38         }
  39
  40         return IPT_CONTINUE;
  41 }
  42
  43 static int
  44 checkentry(const char *tablename,
  45            const struct ipt_entry *e,
  46            void *targinfo,
  47            unsigned int targinfosize,
  48            unsigned int hook_mask)
  49 {
  50         if (targinfosize != IPT_ALIGN(sizeof(struct ipt_classify_target_info))){
  51                 printk(KERN_ERR "CLASSIFY: invalid size (%u != %Zu).\n",
  52                        targinfosize,
  53                        IPT_ALIGN(sizeof(struct ipt_classify_target_info)));
  54                 return 0;
  55         }
  56
  57         if (hook_mask & ~((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_FORWARD) |
  58                           (1 << NF_IP_POST_ROUTING))) {
  59                 printk(KERN_ERR "CLASSIFY: only valid in LOCAL_OUT, FORWARD "
  60                                 "and POST_ROUTING.\n");
  61                 return 0;
  62         }
  63
  64         if (strcmp(tablename, "mangle") != 0) {
  65                 printk(KERN_ERR "CLASSIFY: can only be called from "
  66                                 "\"mangle\" table, not \"%s\".\n",
  67                                 tablename);
  68                 return 0;
  69         }
  70
  71         return 1;
  72 }
  73
  74 static struct ipt_target ipt_classify_reg = {
  75         .name           = "CLASSIFY",
  76         .target         = target,
  77         .checkentry     = checkentry,
  78         .me             = THIS_MODULE,
  79 };
  80
  81 static int __init init(void)
  82 {
  83         return ipt_register_target(&ipt_classify_reg);
  84 }
  85
  86 static void __exit fini(void)
  87 {
  88         ipt_unregister_target(&ipt_classify_reg);
  89 }
  90
  91 module_init(init);
  92 module_exit(fini);