net/netfilter/nf_conntrack_labels.c

   1 /*
   2  * test/set flag bits stored in conntrack extension area.
   3  *
   4  * (C) 2013 Astaro GmbH & Co KG
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/ctype.h>
  12 #include <linux/export.h>
  13 #include <linux/jhash.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/types.h>
  16 #include <linux/slab.h>
  17
  18 #include <net/netfilter/nf_conntrack_ecache.h>
  19 #include <net/netfilter/nf_conntrack_labels.h>
  20
  21 static unsigned int label_bits(const struct nf_conn_labels *l)
  22 {
  23         unsigned int longs = l->words;
  24         return longs * BITS_PER_LONG;
  25 }
  26
  27 bool nf_connlabel_match(const struct nf_conn *ct, u16 bit)
  28 {
  29         struct nf_conn_labels *labels = nf_ct_labels_find(ct);
  30
  31         if (!labels)
  32                 return false;
  33
  34         return bit < label_bits(labels) && test_bit(bit, labels->bits);
  35 }
  36 EXPORT_SYMBOL_GPL(nf_connlabel_match);
  37
  38 int nf_connlabel_set(struct nf_conn *ct, u16 bit)
  39 {
  40         struct nf_conn_labels *labels = nf_ct_labels_find(ct);
  41
  42         if (!labels || bit >= label_bits(labels))
  43                 return -ENOSPC;
  44
  45         if (test_bit(bit, labels->bits))
  46                 return 0;
  47
  48         if (test_and_set_bit(bit, labels->bits))
  49                 return 0;
  50
  51         return 0;
  52 }
  53 EXPORT_SYMBOL_GPL(nf_connlabel_set);
  54
  55 static struct nf_ct_ext_type labels_extend __read_mostly = {
  56         .len    = sizeof(struct nf_conn_labels),
  57         .align  = __alignof__(struct nf_conn_labels),
  58         .id     = NF_CT_EXT_LABELS,
  59 };
  60
  61 int nf_conntrack_labels_init(struct net *net)
  62 {
  63         if (net_eq(net, &init_net))
  64                 return nf_ct_extend_register(&labels_extend);
  65         return 0;
  66 }
  67
  68 void nf_conntrack_labels_fini(struct net *net)
  69 {
  70         if (net_eq(net, &init_net))
  71                 nf_ct_extend_unregister(&labels_extend);
  72 }