net/sched/em_ipset.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * net/sched/em_ipset.c ipset ematch
   4  *
   5  * Copyright (c) 2012 Florian Westphal <fw@strlen.de>
   6  */
   7
   8 #include <linux/gfp.h>
   9 #include <linux/module.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/string.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netfilter/xt_set.h>
  15 #include <linux/ipv6.h>
  16 #include <net/ip.h>
  17 #include <net/pkt_cls.h>
  18
  19 static int em_ipset_change(struct net *net, void *data, int data_len,
  20                            struct tcf_ematch *em)
  21 {
  22         struct xt_set_info *set = data;
  23         ip_set_id_t index;
  24
  25         if (data_len != sizeof(*set))
  26                 return -EINVAL;
  27
  28         index = ip_set_nfnl_get_byindex(net, set->index);
  29         if (index == IPSET_INVALID_ID)
  30                 return -ENOENT;
  31
  32         em->datalen = sizeof(*set);
  33         em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
  34         if (em->data)
  35                 return 0;
  36
  37         ip_set_nfnl_put(net, index);
  38         return -ENOMEM;
  39 }
  40
  41 static void em_ipset_destroy(struct tcf_ematch *em)
  42 {
  43         const struct xt_set_info *set = (const void *) em->data;
  44         if (set) {
  45                 ip_set_nfnl_put(em->net, set->index);
  46                 kfree((void *) em->data);
  47         }
  48 }
  49
  50 static int em_ipset_match(struct sk_buff *skb, struct tcf_ematch *em,
  51                           struct tcf_pkt_info *info)
  52 {
  53         struct ip_set_adt_opt opt;
  54         struct xt_action_param acpar;
  55         const struct xt_set_info *set = (const void *) em->data;
  56         struct net_device *dev, *indev = NULL;
  57         struct nf_hook_state state = {
  58                 .net    = em->net,
  59         };
  60         int ret, network_offset;
  61
  62         switch (skb_protocol(skb, true)) {
  63         case htons(ETH_P_IP):
  64                 state.pf = NFPROTO_IPV4;
  65                 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
  66                         return 0;
  67                 acpar.thoff = ip_hdrlen(skb);
  68                 break;
  69         case htons(ETH_P_IPV6):
  70                 state.pf = NFPROTO_IPV6;
  71                 if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
  72                         return 0;
  73                 /* doesn't call ipv6_find_hdr() because ipset doesn't use thoff, yet */
  74                 acpar.thoff = sizeof(struct ipv6hdr);
  75                 break;
  76         default:
  77                 return 0;
  78         }
  79
  80         opt.family = state.pf;
  81         opt.dim = set->dim;
  82         opt.flags = set->flags;
  83         opt.cmdflags = 0;
  84         opt.ext.timeout = ~0u;
  85
  86         network_offset = skb_network_offset(skb);
  87         skb_pull(skb, network_offset);
  88
  89         dev = skb->dev;
  90
  91         rcu_read_lock();
  92
  93         if (skb->skb_iif)
  94                 indev = dev_get_by_index_rcu(em->net, skb->skb_iif);
  95
  96         state.in      = indev ? indev : dev;
  97         state.out     = dev;
  98         acpar.state   = &state;
  99
 100         ret = ip_set_test(set->index, skb, &acpar, &opt);
 101
 102         rcu_read_unlock();
 103
 104         skb_push(skb, network_offset);
 105         return ret;
 106 }
 107
 108 static struct tcf_ematch_ops em_ipset_ops = {
 109         .kind     = TCF_EM_IPSET,
 110         .change   = em_ipset_change,
 111         .destroy  = em_ipset_destroy,
 112         .match    = em_ipset_match,
 113         .owner    = THIS_MODULE,
 114         .link     = LIST_HEAD_INIT(em_ipset_ops.link)
 115 };
 116
 117 static int __init init_em_ipset(void)
 118 {
 119         return tcf_em_register(&em_ipset_ops);
 120 }
 121
 122 static void __exit exit_em_ipset(void)
 123 {
 124         tcf_em_unregister(&em_ipset_ops);
 125 }
 126
 127 MODULE_LICENSE("GPL");
 128 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
 129 MODULE_DESCRIPTION("TC extended match for IP sets");
 130
 131 module_init(init_em_ipset);
 132 module_exit(exit_em_ipset);
 133
 134 MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPSET);