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 
17 static spinlock_t nf_connlabels_lock;
18 
19 static 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 
25 bool 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 }
34 EXPORT_SYMBOL_GPL(nf_connlabel_match);
35 
36 int 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 }
51 EXPORT_SYMBOL_GPL(nf_connlabel_set);
52 
53 static 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 
63 int 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 }
92 EXPORT_SYMBOL_GPL(nf_connlabels_replace);
93 
94 int 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 }
111 EXPORT_SYMBOL_GPL(nf_connlabels_get);
112 
113 void 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 }
121 EXPORT_SYMBOL_GPL(nf_connlabels_put);
122 
123 static 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 
129 int nf_conntrack_labels_init(void)
130 {
131 	spin_lock_init(&nf_connlabels_lock);
132 	return nf_ct_extend_register(&labels_extend);
133 }
134 
135 void nf_conntrack_labels_fini(void)
136 {
137 	nf_ct_extend_unregister(&labels_extend);
138 }
139