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https://github.com/torvalds/linux
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643d126036
The spinlock is back from the day when connabels did not have a fixed size and reallocation had to be supported. Remove it. This change also allows to call the helpers from softirq or timers without deadlocks. Also add WARN()s to catch refcounting imbalances. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* test/set flag bits stored in conntrack extension area.
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*
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* (C) 2013 Astaro GmbH & Co KG
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*/
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#include <linux/export.h>
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#include <linux/types.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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#include <net/netfilter/nf_conntrack_labels.h>
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static int replace_u32(u32 *address, u32 mask, u32 new)
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{
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u32 old, tmp;
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do {
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old = *address;
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tmp = (old & mask) ^ new;
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if (old == tmp)
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return 0;
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} while (cmpxchg(address, old, tmp) != old);
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return 1;
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}
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int nf_connlabels_replace(struct nf_conn *ct,
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const u32 *data,
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const u32 *mask, unsigned int words32)
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{
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struct nf_conn_labels *labels;
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unsigned int size, i;
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int changed = 0;
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u32 *dst;
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labels = nf_ct_labels_find(ct);
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if (!labels)
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return -ENOSPC;
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size = sizeof(labels->bits);
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if (size < (words32 * sizeof(u32)))
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words32 = size / sizeof(u32);
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dst = (u32 *) labels->bits;
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for (i = 0; i < words32; i++)
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changed |= replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
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size /= sizeof(u32);
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for (i = words32; i < size; i++) /* pad */
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replace_u32(&dst[i], 0, 0);
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if (changed)
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nf_conntrack_event_cache(IPCT_LABEL, ct);
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return 0;
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}
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EXPORT_SYMBOL_GPL(nf_connlabels_replace);
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int nf_connlabels_get(struct net *net, unsigned int bits)
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{
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int v;
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if (BIT_WORD(bits) >= NF_CT_LABELS_MAX_SIZE / sizeof(long))
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return -ERANGE;
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BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE / sizeof(long) >= U8_MAX);
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v = atomic_inc_return_relaxed(&net->ct.labels_used);
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WARN_ON_ONCE(v <= 0);
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return 0;
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}
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EXPORT_SYMBOL_GPL(nf_connlabels_get);
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void nf_connlabels_put(struct net *net)
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{
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int v = atomic_dec_return_relaxed(&net->ct.labels_used);
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WARN_ON_ONCE(v < 0);
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}
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EXPORT_SYMBOL_GPL(nf_connlabels_put);
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