// SPDX-License-Identifier: GPL-2.0-only
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/*
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* xt_hashlimit - Netfilter module to limit the number of packets per time
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* separately for each hashbucket (sourceip/sourceport/dstip/dstport)
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*
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* (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
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* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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*
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* Development of this code was funded by Astaro AG, http://www.astaro.com/
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/random.h>
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#include <linux/jhash.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/list.h>
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#include <linux/skbuff.h>
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#include <linux/mm.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#endif
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/mutex.h>
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#include <linux/kernel.h>
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#include <linux/refcount.h>
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#include <uapi/linux/netfilter/xt_hashlimit.h>
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#define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \
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XT_HASHLIMIT_HASH_SIP | XT_HASHLIMIT_HASH_SPT | \
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XT_HASHLIMIT_INVERT | XT_HASHLIMIT_BYTES |\
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XT_HASHLIMIT_RATE_MATCH)
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
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MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
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MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
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MODULE_ALIAS("ipt_hashlimit");
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MODULE_ALIAS("ip6t_hashlimit");
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struct hashlimit_net {
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struct hlist_head htables;
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struct proc_dir_entry *ipt_hashlimit;
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struct proc_dir_entry *ip6t_hashlimit;
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};
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static unsigned int hashlimit_net_id;
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static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
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{
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return net_generic(net, hashlimit_net_id);
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}
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/* need to declare this at the top */
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static const struct seq_operations dl_seq_ops_v2;
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static const struct seq_operations dl_seq_ops_v1;
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static const struct seq_operations dl_seq_ops;
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/* hash table crap */
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struct dsthash_dst {
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union {
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struct {
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__be32 src;
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__be32 dst;
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} ip;
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#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
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struct {
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__be32 src[4];
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__be32 dst[4];
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} ip6;
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#endif
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};
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__be16 src_port;
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__be16 dst_port;
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};
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struct dsthash_ent {
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/* static / read-only parts in the beginning */
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struct hlist_node node;
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struct dsthash_dst dst;
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/* modified structure members in the end */
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spinlock_t lock;
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unsigned long expires; /* precalculated expiry time */
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struct {
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unsigned long prev; /* last modification */
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union {
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struct {
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u_int64_t credit;
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u_int64_t credit_cap;
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u_int64_t cost;
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};
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struct {
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u_int32_t interval, prev_window;
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u_int64_t current_rate;
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u_int64_t rate;
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int64_t burst;
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};
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};
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} rateinfo;
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struct rcu_head rcu;
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};
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struct xt_hashlimit_htable {
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struct hlist_node node; /* global list of all htables */
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refcount_t use;
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u_int8_t family;
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bool rnd_initialized;
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struct hashlimit_cfg3 cfg; /* config */
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/* used internally */
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spinlock_t lock; /* lock for list_head */
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u_int32_t rnd; /* random seed for hash */
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unsigned int count; /* number entries in table */
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struct delayed_work gc_work;
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/* seq_file stuff */
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struct proc_dir_entry *pde;
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const char *name;
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struct net *net;
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struct hlist_head hash[]; /* hashtable itself */
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};
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static int
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cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision)
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{
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if (revision == 1) {
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struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from;
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to->mode = cfg->mode;
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to->avg = cfg->avg;
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to->burst = cfg->burst;
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to->size = cfg->size;
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to->max = cfg->max;
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to->gc_interval = cfg->gc_interval;
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to->expire = cfg->expire;
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to->srcmask = cfg->srcmask;
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to->dstmask = cfg->dstmask;
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} else if (revision == 2) {
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struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from;
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to->mode = cfg->mode;
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to->avg = cfg->avg;
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to->burst = cfg->burst;
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to->size = cfg->size;
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to->max = cfg->max;
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to->gc_interval = cfg->gc_interval;
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to->expire = cfg->expire;
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to->srcmask = cfg->srcmask;
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to->dstmask = cfg->dstmask;
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} else if (revision == 3) {
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memcpy(to, from, sizeof(struct hashlimit_cfg3));
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} else {
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return -EINVAL;
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}
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return 0;
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}
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static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
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static struct kmem_cache *hashlimit_cachep __read_mostly;
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static inline bool dst_cmp(const struct dsthash_ent *ent,
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const struct dsthash_dst *b)
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{
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return !memcmp(&ent->dst, b, sizeof(ent->dst));
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}
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static u_int32_t
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hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
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{
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u_int32_t hash = jhash2((const u32 *)dst,
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sizeof(*dst)/sizeof(u32),
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ht->rnd);
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/*
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* Instead of returning hash % ht->cfg.size (implying a divide)
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* we return the high 32 bits of the (hash * ht->cfg.size) that will
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* give results between [0 and cfg.size-1] and same hash distribution,
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* but using a multiply, less expensive than a divide
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*/
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return reciprocal_scale(hash, ht->cfg.size);
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}
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static struct dsthash_ent *
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dsthash_find(const struct xt_hashlimit_htable *ht,
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const struct dsthash_dst *dst)
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{
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struct dsthash_ent *ent;
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u_int32_t hash = hash_dst(ht, dst);
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if (!hlist_empty(&ht->hash[hash])) {
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hlist_for_each_entry_rcu(ent, &ht->hash[hash], node)
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if (dst_cmp(ent, dst)) {
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spin_lock(&ent->lock);
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return ent;
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}
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}
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return NULL;
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}
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/* allocate dsthash_ent, initialize dst, put in htable and lock it */
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static struct dsthash_ent *
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dsthash_alloc_init(struct xt_hashlimit_htable *ht,
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const struct dsthash_dst *dst, bool *race)
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{
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struct dsthash_ent *ent;
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spin_lock(&ht->lock);
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/* Two or more packets may race to create the same entry in the
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* hashtable, double check if this packet lost race.
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*/
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ent = dsthash_find(ht, dst);
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if (ent != NULL) {
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spin_unlock(&ht->lock);
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*race = true;
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return ent;
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}
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/* initialize hash with random val at the time we allocate
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* the first hashtable entry */
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if (unlikely(!ht->rnd_initialized)) {
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get_random_bytes(&ht->rnd, sizeof(ht->rnd));
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ht->rnd_initialized = true;
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}
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if (ht->cfg.max && ht->count >= ht->cfg.max) {
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/* FIXME: do something. question is what.. */
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net_err_ratelimited("max count of %u reached\n", ht->cfg.max);
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ent = NULL;
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} else
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ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
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if (ent) {
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memcpy(&ent->dst, dst, sizeof(ent->dst));
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spin_lock_init(&ent->lock);
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spin_lock(&ent->lock);
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hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]);
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ht->count++;
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}
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spin_unlock(&ht->lock);
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return ent;
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}
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static void dsthash_free_rcu(struct rcu_head *head)
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{
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struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
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kmem_cache_free(hashlimit_cachep, ent);
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}
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static inline void
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dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
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{
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hlist_del_rcu(&ent->node);
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call_rcu(&ent->rcu, dsthash_free_rcu);
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ht->count--;
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}
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static void htable_gc(struct work_struct *work);
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static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg,
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const char *name, u_int8_t family,
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struct xt_hashlimit_htable **out_hinfo,
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int revision)
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{
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struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
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struct xt_hashlimit_htable *hinfo;
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const struct seq_operations *ops;
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unsigned int size, i;
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unsigned long nr_pages = totalram_pages();
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int ret;
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if (cfg->size) {
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size = cfg->size;
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} else {
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size = (nr_pages << PAGE_SHIFT) / 16384 /
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sizeof(struct hlist_head);
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if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
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size = 8192;
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if (size < 16)
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size = 16;
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}
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/* FIXME: don't use vmalloc() here or anywhere else -HW */
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hinfo = vmalloc(struct_size(hinfo, hash, size));
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if (hinfo == NULL)
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return -ENOMEM;
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*out_hinfo = hinfo;
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/* copy match config into hashtable config */
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ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3);
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if (ret) {
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vfree(hinfo);
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return ret;
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}
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hinfo->cfg.size = size;
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if (hinfo->cfg.max == 0)
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hinfo->cfg.max = 8 * hinfo->cfg.size;
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else if (hinfo->cfg.max < hinfo->cfg.size)
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hinfo->cfg.max = hinfo->cfg.size;
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for (i = 0; i < hinfo->cfg.size; i++)
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INIT_HLIST_HEAD(&hinfo->hash[i]);
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refcount_set(&hinfo->use, 1);
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hinfo->count = 0;
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hinfo->family = family;
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hinfo->rnd_initialized = false;
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hinfo->name = kstrdup(name, GFP_KERNEL);
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if (!hinfo->name) {
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vfree(hinfo);
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return -ENOMEM;
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}
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spin_lock_init(&hinfo->lock);
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switch (revision) {
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case 1:
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ops = &dl_seq_ops_v1;
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break;
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case 2:
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ops = &dl_seq_ops_v2;
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break;
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default:
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ops = &dl_seq_ops;
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}
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hinfo->pde = proc_create_seq_data(name, 0,
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(family == NFPROTO_IPV4) ?
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hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
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ops, hinfo);
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if (hinfo->pde == NULL) {
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kfree(hinfo->name);
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vfree(hinfo);
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return -ENOMEM;
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}
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hinfo->net = net;
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INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
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queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work,
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msecs_to_jiffies(hinfo->cfg.gc_interval));
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hlist_add_head(&hinfo->node, &hashlimit_net->htables);
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return 0;
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}
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static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, bool select_all)
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{
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unsigned int i;
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for (i = 0; i < ht->cfg.size; i++) {
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struct dsthash_ent *dh;
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struct hlist_node *n;
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spin_lock_bh(&ht->lock);
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hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
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if (time_after_eq(jiffies, dh->expires) || select_all)
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dsthash_free(ht, dh);
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}
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spin_unlock_bh(&ht->lock);
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cond_resched();
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}
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}
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static void htable_gc(struct work_struct *work)
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{
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struct xt_hashlimit_htable *ht;
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ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
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htable_selective_cleanup(ht, false);
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queue_delayed_work(system_power_efficient_wq,
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&ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
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}
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static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
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{
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struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
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struct proc_dir_entry *parent;
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if (hinfo->family == NFPROTO_IPV4)
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parent = hashlimit_net->ipt_hashlimit;
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else
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parent = hashlimit_net->ip6t_hashlimit;
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if (parent != NULL)
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remove_proc_entry(hinfo->name, parent);
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}
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static struct xt_hashlimit_htable *htable_find_get(struct net *net,
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const char *name,
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u_int8_t family)
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{
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struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
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struct xt_hashlimit_htable *hinfo;
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hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
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if (!strcmp(name, hinfo->name) &&
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hinfo->family == family) {
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refcount_inc(&hinfo->use);
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return hinfo;
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}
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}
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return NULL;
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}
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static void htable_put(struct xt_hashlimit_htable *hinfo)
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{
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if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) {
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hlist_del(&hinfo->node);
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htable_remove_proc_entry(hinfo);
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mutex_unlock(&hashlimit_mutex);
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cancel_delayed_work_sync(&hinfo->gc_work);
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htable_selective_cleanup(hinfo, true);
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kfree(hinfo->name);
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vfree(hinfo);
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}
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}
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/* The algorithm used is the Simple Token Bucket Filter (TBF)
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* see net/sched/sch_tbf.c in the linux source tree
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*/
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/* Rusty: This is my (non-mathematically-inclined) understanding of
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this algorithm. The `average rate' in jiffies becomes your initial
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amount of credit `credit' and the most credit you can ever have
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`credit_cap'. The `peak rate' becomes the cost of passing the
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test, `cost'.
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`prev' tracks the last packet hit: you gain one credit per jiffy.
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If you get credit balance more than this, the extra credit is
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discarded. Every time the match passes, you lose `cost' credits;
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if you don't have that many, the test fails.
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See Alexey's formal explanation in net/sched/sch_tbf.c.
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To get the maximum range, we multiply by this factor (ie. you get N
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credits per jiffy). We want to allow a rate as low as 1 per day
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(slowest userspace tool allows), which means
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CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
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*/
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#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
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#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
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/* Repeated shift and or gives us all 1s, final shift and add 1 gives
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* us the power of 2 below the theoretical max, so GCC simply does a
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* shift. */
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#define _POW2_BELOW2(x) ((x)|((x)>>1))
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#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
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#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
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#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
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#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
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#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
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#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
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#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
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#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
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#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
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/* in byte mode, the lowest possible rate is one packet/second.
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* credit_cap is used as a counter that tells us how many times we can
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* refill the "credits available" counter when it becomes empty.
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*/
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#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
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#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
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static u32 xt_hashlimit_len_to_chunks(u32 len)
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{
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return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
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}
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/* Precision saver. */
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static u64 user2credits(u64 user, int revision)
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{
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u64 scale = (revision == 1) ?
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XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
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u64 cpj = (revision == 1) ?
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CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
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/* Avoid overflow: divide the constant operands first */
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if (scale >= HZ * cpj)
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return div64_u64(user, div64_u64(scale, HZ * cpj));
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return user * div64_u64(HZ * cpj, scale);
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}
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static u32 user2credits_byte(u32 user)
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{
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u64 us = user;
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us *= HZ * CREDITS_PER_JIFFY_BYTES;
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return (u32) (us >> 32);
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}
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static u64 user2rate(u64 user)
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{
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if (user != 0) {
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return div64_u64(XT_HASHLIMIT_SCALE_v2, user);
|
} else {
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pr_info_ratelimited("invalid rate from userspace: %llu\n",
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user);
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return 0;
|
}
|
}
|
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static u64 user2rate_bytes(u32 user)
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{
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u64 r;
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r = user ? U32_MAX / user : U32_MAX;
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return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
|
}
|
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static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
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u32 mode, int revision)
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{
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unsigned long delta = now - dh->rateinfo.prev;
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u64 cap, cpj;
|
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if (delta == 0)
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return;
|
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if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
|
u64 interval = dh->rateinfo.interval * HZ;
|
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if (delta < interval)
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return;
|
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dh->rateinfo.prev = now;
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dh->rateinfo.prev_window =
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((dh->rateinfo.current_rate * interval) >
|
(delta * dh->rateinfo.rate));
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dh->rateinfo.current_rate = 0;
|
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return;
|
}
|
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dh->rateinfo.prev = now;
|
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if (mode & XT_HASHLIMIT_BYTES) {
|
u64 tmp = dh->rateinfo.credit;
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dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
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cap = CREDITS_PER_JIFFY_BYTES * HZ;
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if (tmp >= dh->rateinfo.credit) {/* overflow */
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dh->rateinfo.credit = cap;
|
return;
|
}
|
} else {
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cpj = (revision == 1) ?
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CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
|
dh->rateinfo.credit += delta * cpj;
|
cap = dh->rateinfo.credit_cap;
|
}
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if (dh->rateinfo.credit > cap)
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dh->rateinfo.credit = cap;
|
}
|
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static void rateinfo_init(struct dsthash_ent *dh,
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struct xt_hashlimit_htable *hinfo, int revision)
|
{
|
dh->rateinfo.prev = jiffies;
|
if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
|
dh->rateinfo.prev_window = 0;
|
dh->rateinfo.current_rate = 0;
|
if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
|
dh->rateinfo.rate =
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user2rate_bytes((u32)hinfo->cfg.avg);
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if (hinfo->cfg.burst)
|
dh->rateinfo.burst =
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hinfo->cfg.burst * dh->rateinfo.rate;
|
else
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dh->rateinfo.burst = dh->rateinfo.rate;
|
} else {
|
dh->rateinfo.rate = user2rate(hinfo->cfg.avg);
|
dh->rateinfo.burst =
|
hinfo->cfg.burst + dh->rateinfo.rate;
|
}
|
dh->rateinfo.interval = hinfo->cfg.interval;
|
} else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
|
dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
|
dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
|
dh->rateinfo.credit_cap = hinfo->cfg.burst;
|
} else {
|
dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
|
hinfo->cfg.burst, revision);
|
dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision);
|
dh->rateinfo.credit_cap = dh->rateinfo.credit;
|
}
|
}
|
|
static inline __be32 maskl(__be32 a, unsigned int l)
|
{
|
return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
|
}
|
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
|
{
|
switch (p) {
|
case 0 ... 31:
|
i[0] = maskl(i[0], p);
|
i[1] = i[2] = i[3] = 0;
|
break;
|
case 32 ... 63:
|
i[1] = maskl(i[1], p - 32);
|
i[2] = i[3] = 0;
|
break;
|
case 64 ... 95:
|
i[2] = maskl(i[2], p - 64);
|
i[3] = 0;
|
break;
|
case 96 ... 127:
|
i[3] = maskl(i[3], p - 96);
|
break;
|
case 128:
|
break;
|
}
|
}
|
#endif
|
|
static int
|
hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
|
struct dsthash_dst *dst,
|
const struct sk_buff *skb, unsigned int protoff)
|
{
|
__be16 _ports[2], *ports;
|
u8 nexthdr;
|
int poff;
|
|
memset(dst, 0, sizeof(*dst));
|
|
switch (hinfo->family) {
|
case NFPROTO_IPV4:
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
|
dst->ip.dst = maskl(ip_hdr(skb)->daddr,
|
hinfo->cfg.dstmask);
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
|
dst->ip.src = maskl(ip_hdr(skb)->saddr,
|
hinfo->cfg.srcmask);
|
|
if (!(hinfo->cfg.mode &
|
(XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
|
return 0;
|
nexthdr = ip_hdr(skb)->protocol;
|
break;
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
case NFPROTO_IPV6:
|
{
|
__be16 frag_off;
|
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
|
memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
|
sizeof(dst->ip6.dst));
|
hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
|
}
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
|
memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
|
sizeof(dst->ip6.src));
|
hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
|
}
|
|
if (!(hinfo->cfg.mode &
|
(XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
|
return 0;
|
nexthdr = ipv6_hdr(skb)->nexthdr;
|
protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
|
if ((int)protoff < 0)
|
return -1;
|
break;
|
}
|
#endif
|
default:
|
BUG();
|
return 0;
|
}
|
|
poff = proto_ports_offset(nexthdr);
|
if (poff >= 0) {
|
ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
|
&_ports);
|
} else {
|
_ports[0] = _ports[1] = 0;
|
ports = _ports;
|
}
|
if (!ports)
|
return -1;
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
|
dst->src_port = ports[0];
|
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
|
dst->dst_port = ports[1];
|
return 0;
|
}
|
|
static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
|
{
|
u64 tmp = xt_hashlimit_len_to_chunks(len);
|
tmp = tmp * dh->rateinfo.cost;
|
|
if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
|
tmp = CREDITS_PER_JIFFY_BYTES * HZ;
|
|
if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
|
dh->rateinfo.credit_cap--;
|
dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
|
}
|
return (u32) tmp;
|
}
|
|
static bool
|
hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
|
struct xt_hashlimit_htable *hinfo,
|
const struct hashlimit_cfg3 *cfg, int revision)
|
{
|
unsigned long now = jiffies;
|
struct dsthash_ent *dh;
|
struct dsthash_dst dst;
|
bool race = false;
|
u64 cost;
|
|
if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
|
goto hotdrop;
|
|
local_bh_disable();
|
dh = dsthash_find(hinfo, &dst);
|
if (dh == NULL) {
|
dh = dsthash_alloc_init(hinfo, &dst, &race);
|
if (dh == NULL) {
|
local_bh_enable();
|
goto hotdrop;
|
} else if (race) {
|
/* Already got an entry, update expiration timeout */
|
dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
|
rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
|
} else {
|
dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
|
rateinfo_init(dh, hinfo, revision);
|
}
|
} else {
|
/* update expiration timeout */
|
dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
|
rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
|
}
|
|
if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
|
cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
|
dh->rateinfo.current_rate += cost;
|
|
if (!dh->rateinfo.prev_window &&
|
(dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
|
spin_unlock(&dh->lock);
|
local_bh_enable();
|
return !(cfg->mode & XT_HASHLIMIT_INVERT);
|
} else {
|
goto overlimit;
|
}
|
}
|
|
if (cfg->mode & XT_HASHLIMIT_BYTES)
|
cost = hashlimit_byte_cost(skb->len, dh);
|
else
|
cost = dh->rateinfo.cost;
|
|
if (dh->rateinfo.credit >= cost) {
|
/* below the limit */
|
dh->rateinfo.credit -= cost;
|
spin_unlock(&dh->lock);
|
local_bh_enable();
|
return !(cfg->mode & XT_HASHLIMIT_INVERT);
|
}
|
|
overlimit:
|
spin_unlock(&dh->lock);
|
local_bh_enable();
|
/* default match is underlimit - so over the limit, we need to invert */
|
return cfg->mode & XT_HASHLIMIT_INVERT;
|
|
hotdrop:
|
par->hotdrop = true;
|
return false;
|
}
|
|
static bool
|
hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
|
{
|
const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
|
struct xt_hashlimit_htable *hinfo = info->hinfo;
|
struct hashlimit_cfg3 cfg = {};
|
int ret;
|
|
ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
|
if (ret)
|
return ret;
|
|
return hashlimit_mt_common(skb, par, hinfo, &cfg, 1);
|
}
|
|
static bool
|
hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
|
{
|
const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
|
struct xt_hashlimit_htable *hinfo = info->hinfo;
|
struct hashlimit_cfg3 cfg = {};
|
int ret;
|
|
ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
|
if (ret)
|
return ret;
|
|
return hashlimit_mt_common(skb, par, hinfo, &cfg, 2);
|
}
|
|
static bool
|
hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
|
{
|
const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
|
struct xt_hashlimit_htable *hinfo = info->hinfo;
|
|
return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
|
}
|
|
#define HASHLIMIT_MAX_SIZE 1048576
|
|
static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
|
struct xt_hashlimit_htable **hinfo,
|
struct hashlimit_cfg3 *cfg,
|
const char *name, int revision)
|
{
|
struct net *net = par->net;
|
int ret;
|
|
if (cfg->gc_interval == 0 || cfg->expire == 0)
|
return -EINVAL;
|
if (cfg->size > HASHLIMIT_MAX_SIZE) {
|
cfg->size = HASHLIMIT_MAX_SIZE;
|
pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
|
}
|
if (cfg->max > HASHLIMIT_MAX_SIZE) {
|
cfg->max = HASHLIMIT_MAX_SIZE;
|
pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
|
}
|
if (par->family == NFPROTO_IPV4) {
|
if (cfg->srcmask > 32 || cfg->dstmask > 32)
|
return -EINVAL;
|
} else {
|
if (cfg->srcmask > 128 || cfg->dstmask > 128)
|
return -EINVAL;
|
}
|
|
if (cfg->mode & ~XT_HASHLIMIT_ALL) {
|
pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n",
|
cfg->mode);
|
return -EINVAL;
|
}
|
|
/* Check for overflow. */
|
if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
|
if (cfg->avg == 0 || cfg->avg > U32_MAX) {
|
pr_info_ratelimited("invalid rate\n");
|
return -ERANGE;
|
}
|
|
if (cfg->interval == 0) {
|
pr_info_ratelimited("invalid interval\n");
|
return -EINVAL;
|
}
|
} else if (cfg->mode & XT_HASHLIMIT_BYTES) {
|
if (user2credits_byte(cfg->avg) == 0) {
|
pr_info_ratelimited("overflow, rate too high: %llu\n",
|
cfg->avg);
|
return -EINVAL;
|
}
|
} else if (cfg->burst == 0 ||
|
user2credits(cfg->avg * cfg->burst, revision) <
|
user2credits(cfg->avg, revision)) {
|
pr_info_ratelimited("overflow, try lower: %llu/%llu\n",
|
cfg->avg, cfg->burst);
|
return -ERANGE;
|
}
|
|
mutex_lock(&hashlimit_mutex);
|
*hinfo = htable_find_get(net, name, par->family);
|
if (*hinfo == NULL) {
|
ret = htable_create(net, cfg, name, par->family,
|
hinfo, revision);
|
if (ret < 0) {
|
mutex_unlock(&hashlimit_mutex);
|
return ret;
|
}
|
}
|
mutex_unlock(&hashlimit_mutex);
|
|
return 0;
|
}
|
|
static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par)
|
{
|
struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
|
struct hashlimit_cfg3 cfg = {};
|
int ret;
|
|
ret = xt_check_proc_name(info->name, sizeof(info->name));
|
if (ret)
|
return ret;
|
|
ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
|
if (ret)
|
return ret;
|
|
return hashlimit_mt_check_common(par, &info->hinfo,
|
&cfg, info->name, 1);
|
}
|
|
static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par)
|
{
|
struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
|
struct hashlimit_cfg3 cfg = {};
|
int ret;
|
|
ret = xt_check_proc_name(info->name, sizeof(info->name));
|
if (ret)
|
return ret;
|
|
ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
|
if (ret)
|
return ret;
|
|
return hashlimit_mt_check_common(par, &info->hinfo,
|
&cfg, info->name, 2);
|
}
|
|
static int hashlimit_mt_check(const struct xt_mtchk_param *par)
|
{
|
struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
|
int ret;
|
|
ret = xt_check_proc_name(info->name, sizeof(info->name));
|
if (ret)
|
return ret;
|
|
return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg,
|
info->name, 3);
|
}
|
|
static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par)
|
{
|
const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
|
|
htable_put(info->hinfo);
|
}
|
|
static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par)
|
{
|
const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
|
|
htable_put(info->hinfo);
|
}
|
|
static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
|
{
|
const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
|
|
htable_put(info->hinfo);
|
}
|
|
static struct xt_match hashlimit_mt_reg[] __read_mostly = {
|
{
|
.name = "hashlimit",
|
.revision = 1,
|
.family = NFPROTO_IPV4,
|
.match = hashlimit_mt_v1,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo1),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
|
.checkentry = hashlimit_mt_check_v1,
|
.destroy = hashlimit_mt_destroy_v1,
|
.me = THIS_MODULE,
|
},
|
{
|
.name = "hashlimit",
|
.revision = 2,
|
.family = NFPROTO_IPV4,
|
.match = hashlimit_mt_v2,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo2),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
|
.checkentry = hashlimit_mt_check_v2,
|
.destroy = hashlimit_mt_destroy_v2,
|
.me = THIS_MODULE,
|
},
|
{
|
.name = "hashlimit",
|
.revision = 3,
|
.family = NFPROTO_IPV4,
|
.match = hashlimit_mt,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo3),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
|
.checkentry = hashlimit_mt_check,
|
.destroy = hashlimit_mt_destroy,
|
.me = THIS_MODULE,
|
},
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
{
|
.name = "hashlimit",
|
.revision = 1,
|
.family = NFPROTO_IPV6,
|
.match = hashlimit_mt_v1,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo1),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
|
.checkentry = hashlimit_mt_check_v1,
|
.destroy = hashlimit_mt_destroy_v1,
|
.me = THIS_MODULE,
|
},
|
{
|
.name = "hashlimit",
|
.revision = 2,
|
.family = NFPROTO_IPV6,
|
.match = hashlimit_mt_v2,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo2),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
|
.checkentry = hashlimit_mt_check_v2,
|
.destroy = hashlimit_mt_destroy_v2,
|
.me = THIS_MODULE,
|
},
|
{
|
.name = "hashlimit",
|
.revision = 3,
|
.family = NFPROTO_IPV6,
|
.match = hashlimit_mt,
|
.matchsize = sizeof(struct xt_hashlimit_mtinfo3),
|
.usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
|
.checkentry = hashlimit_mt_check,
|
.destroy = hashlimit_mt_destroy,
|
.me = THIS_MODULE,
|
},
|
#endif
|
};
|
|
/* PROC stuff */
|
static void *dl_seq_start(struct seq_file *s, loff_t *pos)
|
__acquires(htable->lock)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket;
|
|
spin_lock_bh(&htable->lock);
|
if (*pos >= htable->cfg.size)
|
return NULL;
|
|
bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
|
if (!bucket)
|
return ERR_PTR(-ENOMEM);
|
|
*bucket = *pos;
|
return bucket;
|
}
|
|
static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket = v;
|
|
*pos = ++(*bucket);
|
if (*pos >= htable->cfg.size) {
|
kfree(v);
|
return NULL;
|
}
|
return bucket;
|
}
|
|
static void dl_seq_stop(struct seq_file *s, void *v)
|
__releases(htable->lock)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket = v;
|
|
if (!IS_ERR(bucket))
|
kfree(bucket);
|
spin_unlock_bh(&htable->lock);
|
}
|
|
static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family,
|
struct seq_file *s)
|
{
|
switch (family) {
|
case NFPROTO_IPV4:
|
seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n",
|
(long)(ent->expires - jiffies)/HZ,
|
&ent->dst.ip.src,
|
ntohs(ent->dst.src_port),
|
&ent->dst.ip.dst,
|
ntohs(ent->dst.dst_port),
|
ent->rateinfo.credit, ent->rateinfo.credit_cap,
|
ent->rateinfo.cost);
|
break;
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
case NFPROTO_IPV6:
|
seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n",
|
(long)(ent->expires - jiffies)/HZ,
|
&ent->dst.ip6.src,
|
ntohs(ent->dst.src_port),
|
&ent->dst.ip6.dst,
|
ntohs(ent->dst.dst_port),
|
ent->rateinfo.credit, ent->rateinfo.credit_cap,
|
ent->rateinfo.cost);
|
break;
|
#endif
|
default:
|
BUG();
|
}
|
}
|
|
static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family,
|
struct seq_file *s)
|
{
|
struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
|
|
spin_lock(&ent->lock);
|
/* recalculate to show accurate numbers */
|
rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2);
|
|
dl_seq_print(ent, family, s);
|
|
spin_unlock(&ent->lock);
|
return seq_has_overflowed(s);
|
}
|
|
static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family,
|
struct seq_file *s)
|
{
|
struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
|
|
spin_lock(&ent->lock);
|
/* recalculate to show accurate numbers */
|
rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1);
|
|
dl_seq_print(ent, family, s);
|
|
spin_unlock(&ent->lock);
|
return seq_has_overflowed(s);
|
}
|
|
static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
|
struct seq_file *s)
|
{
|
struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
|
|
spin_lock(&ent->lock);
|
/* recalculate to show accurate numbers */
|
rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3);
|
|
dl_seq_print(ent, family, s);
|
|
spin_unlock(&ent->lock);
|
return seq_has_overflowed(s);
|
}
|
|
static int dl_seq_show_v2(struct seq_file *s, void *v)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket = (unsigned int *)v;
|
struct dsthash_ent *ent;
|
|
if (!hlist_empty(&htable->hash[*bucket])) {
|
hlist_for_each_entry(ent, &htable->hash[*bucket], node)
|
if (dl_seq_real_show_v2(ent, htable->family, s))
|
return -1;
|
}
|
return 0;
|
}
|
|
static int dl_seq_show_v1(struct seq_file *s, void *v)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket = v;
|
struct dsthash_ent *ent;
|
|
if (!hlist_empty(&htable->hash[*bucket])) {
|
hlist_for_each_entry(ent, &htable->hash[*bucket], node)
|
if (dl_seq_real_show_v1(ent, htable->family, s))
|
return -1;
|
}
|
return 0;
|
}
|
|
static int dl_seq_show(struct seq_file *s, void *v)
|
{
|
struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
|
unsigned int *bucket = v;
|
struct dsthash_ent *ent;
|
|
if (!hlist_empty(&htable->hash[*bucket])) {
|
hlist_for_each_entry(ent, &htable->hash[*bucket], node)
|
if (dl_seq_real_show(ent, htable->family, s))
|
return -1;
|
}
|
return 0;
|
}
|
|
static const struct seq_operations dl_seq_ops_v1 = {
|
.start = dl_seq_start,
|
.next = dl_seq_next,
|
.stop = dl_seq_stop,
|
.show = dl_seq_show_v1
|
};
|
|
static const struct seq_operations dl_seq_ops_v2 = {
|
.start = dl_seq_start,
|
.next = dl_seq_next,
|
.stop = dl_seq_stop,
|
.show = dl_seq_show_v2
|
};
|
|
static const struct seq_operations dl_seq_ops = {
|
.start = dl_seq_start,
|
.next = dl_seq_next,
|
.stop = dl_seq_stop,
|
.show = dl_seq_show
|
};
|
|
static int __net_init hashlimit_proc_net_init(struct net *net)
|
{
|
struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
|
|
hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
|
if (!hashlimit_net->ipt_hashlimit)
|
return -ENOMEM;
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
|
if (!hashlimit_net->ip6t_hashlimit) {
|
remove_proc_entry("ipt_hashlimit", net->proc_net);
|
return -ENOMEM;
|
}
|
#endif
|
return 0;
|
}
|
|
static void __net_exit hashlimit_proc_net_exit(struct net *net)
|
{
|
struct xt_hashlimit_htable *hinfo;
|
struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
|
|
/* hashlimit_net_exit() is called before hashlimit_mt_destroy().
|
* Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc
|
* entries is empty before trying to remove it.
|
*/
|
mutex_lock(&hashlimit_mutex);
|
hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
|
htable_remove_proc_entry(hinfo);
|
hashlimit_net->ipt_hashlimit = NULL;
|
hashlimit_net->ip6t_hashlimit = NULL;
|
mutex_unlock(&hashlimit_mutex);
|
|
remove_proc_entry("ipt_hashlimit", net->proc_net);
|
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
|
remove_proc_entry("ip6t_hashlimit", net->proc_net);
|
#endif
|
}
|
|
static int __net_init hashlimit_net_init(struct net *net)
|
{
|
struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
|
|
INIT_HLIST_HEAD(&hashlimit_net->htables);
|
return hashlimit_proc_net_init(net);
|
}
|
|
static void __net_exit hashlimit_net_exit(struct net *net)
|
{
|
hashlimit_proc_net_exit(net);
|
}
|
|
static struct pernet_operations hashlimit_net_ops = {
|
.init = hashlimit_net_init,
|
.exit = hashlimit_net_exit,
|
.id = &hashlimit_net_id,
|
.size = sizeof(struct hashlimit_net),
|
};
|
|
static int __init hashlimit_mt_init(void)
|
{
|
int err;
|
|
err = register_pernet_subsys(&hashlimit_net_ops);
|
if (err < 0)
|
return err;
|
err = xt_register_matches(hashlimit_mt_reg,
|
ARRAY_SIZE(hashlimit_mt_reg));
|
if (err < 0)
|
goto err1;
|
|
err = -ENOMEM;
|
hashlimit_cachep = kmem_cache_create("xt_hashlimit",
|
sizeof(struct dsthash_ent), 0, 0,
|
NULL);
|
if (!hashlimit_cachep) {
|
pr_warn("unable to create slab cache\n");
|
goto err2;
|
}
|
return 0;
|
|
err2:
|
xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
|
err1:
|
unregister_pernet_subsys(&hashlimit_net_ops);
|
return err;
|
|
}
|
|
static void __exit hashlimit_mt_exit(void)
|
{
|
xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
|
unregister_pernet_subsys(&hashlimit_net_ops);
|
|
rcu_barrier();
|
kmem_cache_destroy(hashlimit_cachep);
|
}
|
|
module_init(hashlimit_mt_init);
|
module_exit(hashlimit_mt_exit);
|
