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 int nf_connlabel_set(struct nf_conn *ct, u16 bit)
20 {
21 	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
22 
23 	if (!labels || BIT_WORD(bit) >= labels->words)
24 		return -ENOSPC;
25 
26 	if (test_bit(bit, labels->bits))
27 		return 0;
28 
29 	if (!test_and_set_bit(bit, labels->bits))
30 		nf_conntrack_event_cache(IPCT_LABEL, ct);
31 
32 	return 0;
33 }
34 EXPORT_SYMBOL_GPL(nf_connlabel_set);
35 
36 static int replace_u32(u32 *address, u32 mask, u32 new)
37 {
38 	u32 old, tmp;
39 
40 	do {
41 		old = *address;
42 		tmp = (old & mask) ^ new;
43 		if (old == tmp)
44 			return 0;
45 	} while (cmpxchg(address, old, tmp) != old);
46 
47 	return 1;
48 }
49 
50 int nf_connlabels_replace(struct nf_conn *ct,
51 			  const u32 *data,
52 			  const u32 *mask, unsigned int words32)
53 {
54 	struct nf_conn_labels *labels;
55 	unsigned int size, i;
56 	int changed = 0;
57 	u32 *dst;
58 
59 	labels = nf_ct_labels_find(ct);
60 	if (!labels)
61 		return -ENOSPC;
62 
63 	size = labels->words * sizeof(long);
64 	if (size < (words32 * sizeof(u32)))
65 		words32 = size / sizeof(u32);
66 
67 	dst = (u32 *) labels->bits;
68 	for (i = 0; i < words32; i++)
69 		changed |= replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
70 
71 	size /= sizeof(u32);
72 	for (i = words32; i < size; i++) /* pad */
73 		replace_u32(&dst[i], 0, 0);
74 
75 	if (changed)
76 		nf_conntrack_event_cache(IPCT_LABEL, ct);
77 	return 0;
78 }
79 EXPORT_SYMBOL_GPL(nf_connlabels_replace);
80 
81 int nf_connlabels_get(struct net *net, unsigned int bits)
82 {
83 	size_t words;
84 
85 	words = BIT_WORD(bits) + 1;
86 	if (words > NF_CT_LABELS_MAX_SIZE / sizeof(long))
87 		return -ERANGE;
88 
89 	spin_lock(&nf_connlabels_lock);
90 	net->ct.labels_used++;
91 	if (words > net->ct.label_words)
92 		net->ct.label_words = words;
93 	spin_unlock(&nf_connlabels_lock);
94 
95 	return 0;
96 }
97 EXPORT_SYMBOL_GPL(nf_connlabels_get);
98 
99 void nf_connlabels_put(struct net *net)
100 {
101 	spin_lock(&nf_connlabels_lock);
102 	net->ct.labels_used--;
103 	if (net->ct.labels_used == 0)
104 		net->ct.label_words = 0;
105 	spin_unlock(&nf_connlabels_lock);
106 }
107 EXPORT_SYMBOL_GPL(nf_connlabels_put);
108 
109 static struct nf_ct_ext_type labels_extend __read_mostly = {
110 	.len    = sizeof(struct nf_conn_labels),
111 	.align  = __alignof__(struct nf_conn_labels),
112 	.id     = NF_CT_EXT_LABELS,
113 };
114 
115 int nf_conntrack_labels_init(void)
116 {
117 	BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE / sizeof(long) >= U8_MAX);
118 
119 	spin_lock_init(&nf_connlabels_lock);
120 	return nf_ct_extend_register(&labels_extend);
121 }
122 
123 void nf_conntrack_labels_fini(void)
124 {
125 	nf_ct_extend_unregister(&labels_extend);
126 }
127