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/export.h>
12#include <linux/types.h>
13
14#include <net/netfilter/nf_conntrack_ecache.h>
15#include <net/netfilter/nf_conntrack_labels.h>
16
17static spinlock_t nf_connlabels_lock;
18
19static unsigned int label_bits(const struct nf_conn_labels *l)
20{
21	unsigned int longs = l->words;
22	return longs * BITS_PER_LONG;
23}
24
25bool nf_connlabel_match(const struct nf_conn *ct, u16 bit)
26{
27	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
28
29	if (!labels)
30		return false;
31
32	return bit < label_bits(labels) && test_bit(bit, labels->bits);
33}
34EXPORT_SYMBOL_GPL(nf_connlabel_match);
35
36int nf_connlabel_set(struct nf_conn *ct, u16 bit)
37{
38	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
39
40	if (!labels || bit >= label_bits(labels))
41		return -ENOSPC;
42
43	if (test_bit(bit, labels->bits))
44		return 0;
45
46	if (!test_and_set_bit(bit, labels->bits))
47		nf_conntrack_event_cache(IPCT_LABEL, ct);
48
49	return 0;
50}
51EXPORT_SYMBOL_GPL(nf_connlabel_set);
52
53static void replace_u32(u32 *address, u32 mask, u32 new)
54{
55	u32 old, tmp;
56
57	do {
58		old = *address;
59		tmp = (old & mask) ^ new;
60	} while (cmpxchg(address, old, tmp) != old);
61}
62
63int nf_connlabels_replace(struct nf_conn *ct,
64			  const u32 *data,
65			  const u32 *mask, unsigned int words32)
66{
67	struct nf_conn_labels *labels;
68	unsigned int size, i;
69	u32 *dst;
70
71	labels = nf_ct_labels_find(ct);
72	if (!labels)
73		return -ENOSPC;
74
75	size = labels->words * sizeof(long);
76	if (size < (words32 * sizeof(u32)))
77		words32 = size / sizeof(u32);
78
79	dst = (u32 *) labels->bits;
80	if (words32) {
81		for (i = 0; i < words32; i++)
82			replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
83	}
84
85	size /= sizeof(u32);
86	for (i = words32; i < size; i++) /* pad */
87		replace_u32(&dst[i], 0, 0);
88
89	nf_conntrack_event_cache(IPCT_LABEL, ct);
90	return 0;
91}
92EXPORT_SYMBOL_GPL(nf_connlabels_replace);
93
94int nf_connlabels_get(struct net *net, unsigned int n_bits)
95{
96	size_t words;
97
98	if (n_bits > (NF_CT_LABELS_MAX_SIZE * BITS_PER_BYTE))
99		return -ERANGE;
100
101	words = BITS_TO_LONGS(n_bits);
102
103	spin_lock(&nf_connlabels_lock);
104	net->ct.labels_used++;
105	if (words > net->ct.label_words)
106		net->ct.label_words = words;
107	spin_unlock(&nf_connlabels_lock);
108
109	return 0;
110}
111EXPORT_SYMBOL_GPL(nf_connlabels_get);
112
113void nf_connlabels_put(struct net *net)
114{
115	spin_lock(&nf_connlabels_lock);
116	net->ct.labels_used--;
117	if (net->ct.labels_used == 0)
118		net->ct.label_words = 0;
119	spin_unlock(&nf_connlabels_lock);
120}
121EXPORT_SYMBOL_GPL(nf_connlabels_put);
122
123static struct nf_ct_ext_type labels_extend __read_mostly = {
124	.len    = sizeof(struct nf_conn_labels),
125	.align  = __alignof__(struct nf_conn_labels),
126	.id     = NF_CT_EXT_LABELS,
127};
128
129int nf_conntrack_labels_init(void)
130{
131	spin_lock_init(&nf_connlabels_lock);
132	return nf_ct_extend_register(&labels_extend);
133}
134
135void nf_conntrack_labels_fini(void)
136{
137	nf_ct_extend_unregister(&labels_extend);
138}
139