1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * test/set flag bits stored in conntrack extension area.
4  *
5  * (C) 2013 Astaro GmbH & Co KG
6  */
7 
8 #include <linux/export.h>
9 #include <linux/types.h>
10 
11 #include <net/netfilter/nf_conntrack_ecache.h>
12 #include <net/netfilter/nf_conntrack_labels.h>
13 
14 static DEFINE_SPINLOCK(nf_connlabels_lock);
15 
replace_u32(u32 * address,u32 mask,u32 new)16 static int replace_u32(u32 *address, u32 mask, u32 new)
17 {
18 	u32 old, tmp;
19 
20 	do {
21 		old = *address;
22 		tmp = (old & mask) ^ new;
23 		if (old == tmp)
24 			return 0;
25 	} while (cmpxchg(address, old, tmp) != old);
26 
27 	return 1;
28 }
29 
nf_connlabels_replace(struct nf_conn * ct,const u32 * data,const u32 * mask,unsigned int words32)30 int nf_connlabels_replace(struct nf_conn *ct,
31 			  const u32 *data,
32 			  const u32 *mask, unsigned int words32)
33 {
34 	struct nf_conn_labels *labels;
35 	unsigned int size, i;
36 	int changed = 0;
37 	u32 *dst;
38 
39 	labels = nf_ct_labels_find(ct);
40 	if (!labels)
41 		return -ENOSPC;
42 
43 	size = sizeof(labels->bits);
44 	if (size < (words32 * sizeof(u32)))
45 		words32 = size / sizeof(u32);
46 
47 	dst = (u32 *) labels->bits;
48 	for (i = 0; i < words32; i++)
49 		changed |= replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
50 
51 	size /= sizeof(u32);
52 	for (i = words32; i < size; i++) /* pad */
53 		replace_u32(&dst[i], 0, 0);
54 
55 	if (changed)
56 		nf_conntrack_event_cache(IPCT_LABEL, ct);
57 	return 0;
58 }
59 EXPORT_SYMBOL_GPL(nf_connlabels_replace);
60 
nf_connlabels_get(struct net * net,unsigned int bits)61 int nf_connlabels_get(struct net *net, unsigned int bits)
62 {
63 	if (BIT_WORD(bits) >= NF_CT_LABELS_MAX_SIZE / sizeof(long))
64 		return -ERANGE;
65 
66 	spin_lock(&nf_connlabels_lock);
67 	net->ct.labels_used++;
68 	spin_unlock(&nf_connlabels_lock);
69 
70 	BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE / sizeof(long) >= U8_MAX);
71 
72 	return 0;
73 }
74 EXPORT_SYMBOL_GPL(nf_connlabels_get);
75 
nf_connlabels_put(struct net * net)76 void nf_connlabels_put(struct net *net)
77 {
78 	spin_lock(&nf_connlabels_lock);
79 	net->ct.labels_used--;
80 	spin_unlock(&nf_connlabels_lock);
81 }
82 EXPORT_SYMBOL_GPL(nf_connlabels_put);
83