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 net *net, 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
  28         if (data_len != sizeof(*set))
  29                 return -EINVAL;
  30
  31         index = ip_set_nfnl_get_byindex(net, set->index);
  32         if (index == IPSET_INVALID_ID)
  33                 return -ENOENT;
  34
  35         em->datalen = sizeof(*set);
  36         em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
  37         if (em->data)
  38                 return 0;
  39
  40         ip_set_nfnl_put(net, index);
  41         return -ENOMEM;
  42 }
  43
  44 static void em_ipset_destroy(struct tcf_ematch *em)
  45 {
  46         const struct xt_set_info *set = (const void *) em->data;
  47         if (set) {
  48                 ip_set_nfnl_put(em->net, set->index);
  49                 kfree((void *) em->data);
  50         }
  51 }
  52
  53 static int em_ipset_match(struct sk_buff *skb, struct tcf_ematch *em,
  54                           struct tcf_pkt_info *info)
  55 {
  56         struct ip_set_adt_opt opt;
  57         struct xt_action_param acpar;
  58         const struct xt_set_info *set = (const void *) em->data;
  59         struct net_device *dev, *indev = NULL;
  60         struct nf_hook_state state = {
  61                 .net    = em->net,
  62         };
  63         int ret, network_offset;
  64
  65         switch (tc_skb_protocol(skb)) {
  66         case htons(ETH_P_IP):
  67                 state.pf = NFPROTO_IPV4;
  68                 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
  69                         return 0;
  70                 acpar.thoff = ip_hdrlen(skb);
  71                 break;
  72         case htons(ETH_P_IPV6):
  73                 state.pf = NFPROTO_IPV6;
  74                 if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
  75                         return 0;
  76                 /* doesn't call ipv6_find_hdr() because ipset doesn't use thoff, yet */
  77                 acpar.thoff = sizeof(struct ipv6hdr);
  78                 break;
  79         default:
  80                 return 0;
  81         }
  82
  83         opt.family = state.pf;
  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 (skb->skb_iif)
  97                 indev = dev_get_by_index_rcu(em->net, skb->skb_iif);
  98
  99         state.in      = indev ? indev : dev;
 100         state.out     = dev;
 101         acpar.state   = &state;
 102
 103         ret = ip_set_test(set->index, skb, &acpar, &opt);
 104
 105         rcu_read_unlock();
 106
 107         skb_push(skb, network_offset);
 108         return ret;
 109 }
 110
 111 static struct tcf_ematch_ops em_ipset_ops = {
 112         .kind     = TCF_EM_IPSET,
 113         .change   = em_ipset_change,
 114         .destroy  = em_ipset_destroy,
 115         .match    = em_ipset_match,
 116         .owner    = THIS_MODULE,
 117         .link     = LIST_HEAD_INIT(em_ipset_ops.link)
 118 };
 119
 120 static int __init init_em_ipset(void)
 121 {
 122         return tcf_em_register(&em_ipset_ops);
 123 }
 124
 125 static void __exit exit_em_ipset(void)
 126 {
 127         tcf_em_unregister(&em_ipset_ops);
 128 }
 129
 130 MODULE_LICENSE("GPL");
 131 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
 132 MODULE_DESCRIPTION("TC extended match for IP sets");
 133
 134 module_init(init_em_ipset);
 135 module_exit(exit_em_ipset);
 136
 137 MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPSET);