net/sched/em_ipset.c

   1 /*
   2  * net/sched/em_ipset.c ipset ematch
   3  *
   4  * Copyright (c) 2012 Florian Westphal <fw@strlen.de>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * version 2 as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/gfp.h>
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/netfilter/xt_set.h>
  18 #include <linux/ipv6.h>
  19 #include <net/ip.h>
  20 #include <net/pkt_cls.h>
  21
  22 static int em_ipset_change(struct tcf_proto *tp, void *data, int data_len,
  23                            struct tcf_ematch *em)
  24 {
  25         struct xt_set_info *set = data;
  26         ip_set_id_t index;
  27         struct net *net = dev_net(qdisc_dev(tp->q));
  28
  29         if (data_len != sizeof(*set))
  30                 return -EINVAL;
  31
  32         index = ip_set_nfnl_get_byindex(net, set->index);
  33         if (index == IPSET_INVALID_ID)
  34                 return -ENOENT;
  35
  36         em->datalen = sizeof(*set);
  37         em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
  38         if (em->data)
  39                 return 0;
  40
  41         ip_set_nfnl_put(net, index);
  42         return -ENOMEM;
  43 }
  44
  45 static void em_ipset_destroy(struct tcf_proto *p, struct tcf_ematch *em)
  46 {
  47         const struct xt_set_info *set = (const void *) em->data;
  48         if (set) {
  49                 ip_set_nfnl_put(dev_net(qdisc_dev(p->q)), set->index);
  50                 kfree((void *) em->data);
  51         }
  52 }
  53
  54 static int em_ipset_match(struct sk_buff *skb, struct tcf_ematch *em,
  55                           struct tcf_pkt_info *info)
  56 {
  57         struct ip_set_adt_opt opt;
  58         struct xt_action_param acpar;
  59         const struct xt_set_info *set = (const void *) em->data;
  60         struct net_device *dev, *indev = NULL;
  61         int ret, network_offset;
  62
  63         switch (skb->protocol) {
  64         case htons(ETH_P_IP):
  65                 acpar.family = NFPROTO_IPV4;
  66                 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
  67                         return 0;
  68                 acpar.thoff = ip_hdrlen(skb);
  69                 break;
  70         case htons(ETH_P_IPV6):
  71                 acpar.family = NFPROTO_IPV6;
  72                 if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
  73                         return 0;
  74                 /* doesn't call ipv6_find_hdr() because ipset doesn't use thoff, yet */
  75                 acpar.thoff = sizeof(struct ipv6hdr);
  76                 break;
  77         default:
  78                 return 0;
  79         }
  80
  81         acpar.hooknum = 0;
  82
  83         opt.family = acpar.family;
  84         opt.dim = set->dim;
  85         opt.flags = set->flags;
  86         opt.cmdflags = 0;
  87         opt.ext.timeout = ~0u;
  88
  89         network_offset = skb_network_offset(skb);
  90         skb_pull(skb, network_offset);
  91
  92         dev = skb->dev;
  93
  94         rcu_read_lock();
  95
  96         if (dev && skb->skb_iif)
  97                 indev = dev_get_by_index_rcu(dev_net(dev), skb->skb_iif);
  98
  99         acpar.in      = indev ? indev : dev;
 100         acpar.out     = dev;
 101
 102         ret = ip_set_test(set->index, skb, &acpar, &opt);
 103
 104         rcu_read_unlock();
 105
 106         skb_push(skb, network_offset);
 107         return ret;
 108 }
 109
 110 static struct tcf_ematch_ops em_ipset_ops = {
 111         .kind     = TCF_EM_IPSET,
 112         .change   = em_ipset_change,
 113         .destroy  = em_ipset_destroy,
 114         .match    = em_ipset_match,
 115         .owner    = THIS_MODULE,
 116         .link     = LIST_HEAD_INIT(em_ipset_ops.link)
 117 };
 118
 119 static int __init init_em_ipset(void)
 120 {
 121         return tcf_em_register(&em_ipset_ops);
 122 }
 123
 124 static void __exit exit_em_ipset(void)
 125 {
 126         tcf_em_unregister(&em_ipset_ops);
 127 }
 128
 129 MODULE_LICENSE("GPL");
 130 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
 131 MODULE_DESCRIPTION("TC extended match for IP sets");
 132
 133 module_init(init_em_ipset);
 134 module_exit(exit_em_ipset);
 135
 136 MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPSET);