| /* |
| * xt_hashlimit - Netfilter module to limit the number of packets per time |
| * seperately for each hashbucket (sourceip/sourceport/dstip/dstport) |
| * |
| * (C) 2003-2004 by Harald Welte <laforge@netfilter.org> |
| * Copyright © CC Computer Consultants GmbH, 2007 - 2008 |
| * |
| * Development of this code was funded by Astaro AG, http://www.astaro.com/ |
| */ |
| #include <linux/module.h> |
| #include <linux/spinlock.h> |
| #include <linux/random.h> |
| #include <linux/jhash.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/list.h> |
| #include <linux/skbuff.h> |
| #include <linux/mm.h> |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| #include <linux/ipv6.h> |
| #include <net/ipv6.h> |
| #endif |
| |
| #include <net/net_namespace.h> |
| |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv6/ip6_tables.h> |
| #include <linux/netfilter/xt_hashlimit.h> |
| #include <linux/mutex.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>"); |
| MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match"); |
| MODULE_ALIAS("ipt_hashlimit"); |
| MODULE_ALIAS("ip6t_hashlimit"); |
| |
| /* need to declare this at the top */ |
| static struct proc_dir_entry *hashlimit_procdir4; |
| static struct proc_dir_entry *hashlimit_procdir6; |
| static const struct file_operations dl_file_ops; |
| |
| /* hash table crap */ |
| struct dsthash_dst { |
| union { |
| struct { |
| __be32 src; |
| __be32 dst; |
| } ip; |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| struct { |
| __be32 src[4]; |
| __be32 dst[4]; |
| } ip6; |
| #endif |
| }; |
| __be16 src_port; |
| __be16 dst_port; |
| }; |
| |
| struct dsthash_ent { |
| /* static / read-only parts in the beginning */ |
| struct hlist_node node; |
| struct dsthash_dst dst; |
| |
| /* modified structure members in the end */ |
| unsigned long expires; /* precalculated expiry time */ |
| struct { |
| unsigned long prev; /* last modification */ |
| u_int32_t credit; |
| u_int32_t credit_cap, cost; |
| } rateinfo; |
| }; |
| |
| struct xt_hashlimit_htable { |
| struct hlist_node node; /* global list of all htables */ |
| atomic_t use; |
| u_int8_t family; |
| |
| struct hashlimit_cfg1 cfg; /* config */ |
| |
| /* used internally */ |
| spinlock_t lock; /* lock for list_head */ |
| u_int32_t rnd; /* random seed for hash */ |
| int rnd_initialized; |
| unsigned int count; /* number entries in table */ |
| struct timer_list timer; /* timer for gc */ |
| |
| /* seq_file stuff */ |
| struct proc_dir_entry *pde; |
| |
| struct hlist_head hash[0]; /* hashtable itself */ |
| }; |
| |
| static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */ |
| static DEFINE_MUTEX(hlimit_mutex); /* additional checkentry protection */ |
| static HLIST_HEAD(hashlimit_htables); |
| static struct kmem_cache *hashlimit_cachep __read_mostly; |
| |
| static inline bool dst_cmp(const struct dsthash_ent *ent, |
| const struct dsthash_dst *b) |
| { |
| return !memcmp(&ent->dst, b, sizeof(ent->dst)); |
| } |
| |
| static u_int32_t |
| hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst) |
| { |
| u_int32_t hash = jhash2((const u32 *)dst, |
| sizeof(*dst)/sizeof(u32), |
| ht->rnd); |
| /* |
| * Instead of returning hash % ht->cfg.size (implying a divide) |
| * we return the high 32 bits of the (hash * ht->cfg.size) that will |
| * give results between [0 and cfg.size-1] and same hash distribution, |
| * but using a multiply, less expensive than a divide |
| */ |
| return ((u64)hash * ht->cfg.size) >> 32; |
| } |
| |
| static struct dsthash_ent * |
| dsthash_find(const struct xt_hashlimit_htable *ht, |
| const struct dsthash_dst *dst) |
| { |
| struct dsthash_ent *ent; |
| struct hlist_node *pos; |
| u_int32_t hash = hash_dst(ht, dst); |
| |
| if (!hlist_empty(&ht->hash[hash])) { |
| hlist_for_each_entry(ent, pos, &ht->hash[hash], node) |
| if (dst_cmp(ent, dst)) |
| return ent; |
| } |
| return NULL; |
| } |
| |
| /* allocate dsthash_ent, initialize dst, put in htable and lock it */ |
| static struct dsthash_ent * |
| dsthash_alloc_init(struct xt_hashlimit_htable *ht, |
| const struct dsthash_dst *dst) |
| { |
| struct dsthash_ent *ent; |
| |
| /* initialize hash with random val at the time we allocate |
| * the first hashtable entry */ |
| if (!ht->rnd_initialized) { |
| get_random_bytes(&ht->rnd, 4); |
| ht->rnd_initialized = 1; |
| } |
| |
| if (ht->cfg.max && ht->count >= ht->cfg.max) { |
| /* FIXME: do something. question is what.. */ |
| if (net_ratelimit()) |
| printk(KERN_WARNING |
| "xt_hashlimit: max count of %u reached\n", |
| ht->cfg.max); |
| return NULL; |
| } |
| |
| ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC); |
| if (!ent) { |
| if (net_ratelimit()) |
| printk(KERN_ERR |
| "xt_hashlimit: can't allocate dsthash_ent\n"); |
| return NULL; |
| } |
| memcpy(&ent->dst, dst, sizeof(ent->dst)); |
| |
| hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]); |
| ht->count++; |
| return ent; |
| } |
| |
| static inline void |
| dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent) |
| { |
| hlist_del(&ent->node); |
| kmem_cache_free(hashlimit_cachep, ent); |
| ht->count--; |
| } |
| static void htable_gc(unsigned long htlong); |
| |
| static int htable_create_v0(struct xt_hashlimit_info *minfo, u_int8_t family) |
| { |
| struct xt_hashlimit_htable *hinfo; |
| unsigned int size; |
| unsigned int i; |
| |
| if (minfo->cfg.size) |
| size = minfo->cfg.size; |
| else { |
| size = ((num_physpages << PAGE_SHIFT) / 16384) / |
| sizeof(struct list_head); |
| if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE)) |
| size = 8192; |
| if (size < 16) |
| size = 16; |
| } |
| /* FIXME: don't use vmalloc() here or anywhere else -HW */ |
| hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) + |
| sizeof(struct list_head) * size); |
| if (!hinfo) { |
| printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n"); |
| return -1; |
| } |
| minfo->hinfo = hinfo; |
| |
| /* copy match config into hashtable config */ |
| hinfo->cfg.mode = minfo->cfg.mode; |
| hinfo->cfg.avg = minfo->cfg.avg; |
| hinfo->cfg.burst = minfo->cfg.burst; |
| hinfo->cfg.max = minfo->cfg.max; |
| hinfo->cfg.gc_interval = minfo->cfg.gc_interval; |
| hinfo->cfg.expire = minfo->cfg.expire; |
| |
| if (family == NFPROTO_IPV4) |
| hinfo->cfg.srcmask = hinfo->cfg.dstmask = 32; |
| else |
| hinfo->cfg.srcmask = hinfo->cfg.dstmask = 128; |
| |
| hinfo->cfg.size = size; |
| if (!hinfo->cfg.max) |
| hinfo->cfg.max = 8 * hinfo->cfg.size; |
| else if (hinfo->cfg.max < hinfo->cfg.size) |
| hinfo->cfg.max = hinfo->cfg.size; |
| |
| for (i = 0; i < hinfo->cfg.size; i++) |
| INIT_HLIST_HEAD(&hinfo->hash[i]); |
| |
| atomic_set(&hinfo->use, 1); |
| hinfo->count = 0; |
| hinfo->family = family; |
| hinfo->rnd_initialized = 0; |
| spin_lock_init(&hinfo->lock); |
| hinfo->pde = proc_create_data(minfo->name, 0, |
| (family == NFPROTO_IPV4) ? |
| hashlimit_procdir4 : hashlimit_procdir6, |
| &dl_file_ops, hinfo); |
| if (!hinfo->pde) { |
| vfree(hinfo); |
| return -1; |
| } |
| |
| setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo); |
| hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval); |
| add_timer(&hinfo->timer); |
| |
| spin_lock_bh(&hashlimit_lock); |
| hlist_add_head(&hinfo->node, &hashlimit_htables); |
| spin_unlock_bh(&hashlimit_lock); |
| |
| return 0; |
| } |
| |
| static int htable_create(struct xt_hashlimit_mtinfo1 *minfo, u_int8_t family) |
| { |
| struct xt_hashlimit_htable *hinfo; |
| unsigned int size; |
| unsigned int i; |
| |
| if (minfo->cfg.size) { |
| size = minfo->cfg.size; |
| } else { |
| size = (num_physpages << PAGE_SHIFT) / 16384 / |
| sizeof(struct list_head); |
| if (num_physpages > 1024 * 1024 * 1024 / PAGE_SIZE) |
| size = 8192; |
| if (size < 16) |
| size = 16; |
| } |
| /* FIXME: don't use vmalloc() here or anywhere else -HW */ |
| hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) + |
| sizeof(struct list_head) * size); |
| if (hinfo == NULL) { |
| printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n"); |
| return -1; |
| } |
| minfo->hinfo = hinfo; |
| |
| /* copy match config into hashtable config */ |
| memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg)); |
| hinfo->cfg.size = size; |
| if (hinfo->cfg.max == 0) |
| hinfo->cfg.max = 8 * hinfo->cfg.size; |
| else if (hinfo->cfg.max < hinfo->cfg.size) |
| hinfo->cfg.max = hinfo->cfg.size; |
| |
| for (i = 0; i < hinfo->cfg.size; i++) |
| INIT_HLIST_HEAD(&hinfo->hash[i]); |
| |
| atomic_set(&hinfo->use, 1); |
| hinfo->count = 0; |
| hinfo->family = family; |
| hinfo->rnd_initialized = 0; |
| spin_lock_init(&hinfo->lock); |
| |
| hinfo->pde = proc_create_data(minfo->name, 0, |
| (family == NFPROTO_IPV4) ? |
| hashlimit_procdir4 : hashlimit_procdir6, |
| &dl_file_ops, hinfo); |
| if (hinfo->pde == NULL) { |
| vfree(hinfo); |
| return -1; |
| } |
| |
| setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo); |
| hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval); |
| add_timer(&hinfo->timer); |
| |
| spin_lock_bh(&hashlimit_lock); |
| hlist_add_head(&hinfo->node, &hashlimit_htables); |
| spin_unlock_bh(&hashlimit_lock); |
| |
| return 0; |
| } |
| |
| static bool select_all(const struct xt_hashlimit_htable *ht, |
| const struct dsthash_ent *he) |
| { |
| return 1; |
| } |
| |
| static bool select_gc(const struct xt_hashlimit_htable *ht, |
| const struct dsthash_ent *he) |
| { |
| return time_after_eq(jiffies, he->expires); |
| } |
| |
| static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, |
| bool (*select)(const struct xt_hashlimit_htable *ht, |
| const struct dsthash_ent *he)) |
| { |
| unsigned int i; |
| |
| /* lock hash table and iterate over it */ |
| spin_lock_bh(&ht->lock); |
| for (i = 0; i < ht->cfg.size; i++) { |
| struct dsthash_ent *dh; |
| struct hlist_node *pos, *n; |
| hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) { |
| if ((*select)(ht, dh)) |
| dsthash_free(ht, dh); |
| } |
| } |
| spin_unlock_bh(&ht->lock); |
| } |
| |
| /* hash table garbage collector, run by timer */ |
| static void htable_gc(unsigned long htlong) |
| { |
| struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong; |
| |
| htable_selective_cleanup(ht, select_gc); |
| |
| /* re-add the timer accordingly */ |
| ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval); |
| add_timer(&ht->timer); |
| } |
| |
| static void htable_destroy(struct xt_hashlimit_htable *hinfo) |
| { |
| del_timer_sync(&hinfo->timer); |
| |
| /* remove proc entry */ |
| remove_proc_entry(hinfo->pde->name, |
| hinfo->family == NFPROTO_IPV4 ? hashlimit_procdir4 : |
| hashlimit_procdir6); |
| htable_selective_cleanup(hinfo, select_all); |
| vfree(hinfo); |
| } |
| |
| static struct xt_hashlimit_htable *htable_find_get(const char *name, |
| u_int8_t family) |
| { |
| struct xt_hashlimit_htable *hinfo; |
| struct hlist_node *pos; |
| |
| spin_lock_bh(&hashlimit_lock); |
| hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) { |
| if (!strcmp(name, hinfo->pde->name) && |
| hinfo->family == family) { |
| atomic_inc(&hinfo->use); |
| spin_unlock_bh(&hashlimit_lock); |
| return hinfo; |
| } |
| } |
| spin_unlock_bh(&hashlimit_lock); |
| return NULL; |
| } |
| |
| static void htable_put(struct xt_hashlimit_htable *hinfo) |
| { |
| if (atomic_dec_and_test(&hinfo->use)) { |
| spin_lock_bh(&hashlimit_lock); |
| hlist_del(&hinfo->node); |
| spin_unlock_bh(&hashlimit_lock); |
| htable_destroy(hinfo); |
| } |
| } |
| |
| /* The algorithm used is the Simple Token Bucket Filter (TBF) |
| * see net/sched/sch_tbf.c in the linux source tree |
| */ |
| |
| /* Rusty: This is my (non-mathematically-inclined) understanding of |
| this algorithm. The `average rate' in jiffies becomes your initial |
| amount of credit `credit' and the most credit you can ever have |
| `credit_cap'. The `peak rate' becomes the cost of passing the |
| test, `cost'. |
| |
| `prev' tracks the last packet hit: you gain one credit per jiffy. |
| If you get credit balance more than this, the extra credit is |
| discarded. Every time the match passes, you lose `cost' credits; |
| if you don't have that many, the test fails. |
| |
| See Alexey's formal explanation in net/sched/sch_tbf.c. |
| |
| To get the maximum range, we multiply by this factor (ie. you get N |
| credits per jiffy). We want to allow a rate as low as 1 per day |
| (slowest userspace tool allows), which means |
| CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie. |
| */ |
| #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24)) |
| |
| /* Repeated shift and or gives us all 1s, final shift and add 1 gives |
| * us the power of 2 below the theoretical max, so GCC simply does a |
| * shift. */ |
| #define _POW2_BELOW2(x) ((x)|((x)>>1)) |
| #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2)) |
| #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4)) |
| #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8)) |
| #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16)) |
| #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1) |
| |
| #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ) |
| |
| /* Precision saver. */ |
| static inline u_int32_t |
| user2credits(u_int32_t user) |
| { |
| /* If multiplying would overflow... */ |
| if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY)) |
| /* Divide first. */ |
| return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY; |
| |
| return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE; |
| } |
| |
| static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now) |
| { |
| dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY; |
| if (dh->rateinfo.credit > dh->rateinfo.credit_cap) |
| dh->rateinfo.credit = dh->rateinfo.credit_cap; |
| dh->rateinfo.prev = now; |
| } |
| |
| static inline __be32 maskl(__be32 a, unsigned int l) |
| { |
| return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0; |
| } |
| |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| 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; |
| 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; |
| |
| 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 defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| case NFPROTO_IPV6: |
| 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); |
| if ((int)protoff < 0) |
| return -1; |
| break; |
| #endif |
| default: |
| BUG(); |
| return 0; |
| } |
| |
| switch (nexthdr) { |
| case IPPROTO_TCP: |
| case IPPROTO_UDP: |
| case IPPROTO_UDPLITE: |
| case IPPROTO_SCTP: |
| case IPPROTO_DCCP: |
| ports = skb_header_pointer(skb, protoff, sizeof(_ports), |
| &_ports); |
| break; |
| default: |
| _ports[0] = _ports[1] = 0; |
| ports = _ports; |
| break; |
| } |
| 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 bool |
| hashlimit_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par) |
| { |
| const struct xt_hashlimit_info *r = |
| ((const struct xt_hashlimit_info *)par->matchinfo)->u.master; |
| struct xt_hashlimit_htable *hinfo = r->hinfo; |
| unsigned long now = jiffies; |
| struct dsthash_ent *dh; |
| struct dsthash_dst dst; |
| |
| if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) |
| goto hotdrop; |
| |
| spin_lock_bh(&hinfo->lock); |
| dh = dsthash_find(hinfo, &dst); |
| if (!dh) { |
| dh = dsthash_alloc_init(hinfo, &dst); |
| if (!dh) { |
| spin_unlock_bh(&hinfo->lock); |
| goto hotdrop; |
| } |
| |
| dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); |
| dh->rateinfo.prev = jiffies; |
| dh->rateinfo.credit = user2credits(hinfo->cfg.avg * |
| hinfo->cfg.burst); |
| dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg * |
| hinfo->cfg.burst); |
| dh->rateinfo.cost = user2credits(hinfo->cfg.avg); |
| } else { |
| /* update expiration timeout */ |
| dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); |
| rateinfo_recalc(dh, now); |
| } |
| |
| if (dh->rateinfo.credit >= dh->rateinfo.cost) { |
| /* We're underlimit. */ |
| dh->rateinfo.credit -= dh->rateinfo.cost; |
| spin_unlock_bh(&hinfo->lock); |
| return true; |
| } |
| |
| spin_unlock_bh(&hinfo->lock); |
| |
| /* default case: we're overlimit, thus don't match */ |
| return false; |
| |
| hotdrop: |
| *par->hotdrop = true; |
| return false; |
| } |
| |
| static bool |
| hashlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
| { |
| const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; |
| struct xt_hashlimit_htable *hinfo = info->hinfo; |
| unsigned long now = jiffies; |
| struct dsthash_ent *dh; |
| struct dsthash_dst dst; |
| |
| if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) |
| goto hotdrop; |
| |
| spin_lock_bh(&hinfo->lock); |
| dh = dsthash_find(hinfo, &dst); |
| if (dh == NULL) { |
| dh = dsthash_alloc_init(hinfo, &dst); |
| if (dh == NULL) { |
| spin_unlock_bh(&hinfo->lock); |
| goto hotdrop; |
| } |
| |
| dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); |
| dh->rateinfo.prev = jiffies; |
| dh->rateinfo.credit = user2credits(hinfo->cfg.avg * |
| hinfo->cfg.burst); |
| dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg * |
| hinfo->cfg.burst); |
| dh->rateinfo.cost = user2credits(hinfo->cfg.avg); |
| } else { |
| /* update expiration timeout */ |
| dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); |
| rateinfo_recalc(dh, now); |
| } |
| |
| if (dh->rateinfo.credit >= dh->rateinfo.cost) { |
| /* below the limit */ |
| dh->rateinfo.credit -= dh->rateinfo.cost; |
| spin_unlock_bh(&hinfo->lock); |
| return !(info->cfg.mode & XT_HASHLIMIT_INVERT); |
| } |
| |
| spin_unlock_bh(&hinfo->lock); |
| /* default match is underlimit - so over the limit, we need to invert */ |
| return info->cfg.mode & XT_HASHLIMIT_INVERT; |
| |
| hotdrop: |
| *par->hotdrop = true; |
| return false; |
| } |
| |
| static bool hashlimit_mt_check_v0(const struct xt_mtchk_param *par) |
| { |
| struct xt_hashlimit_info *r = par->matchinfo; |
| |
| /* Check for overflow. */ |
| if (r->cfg.burst == 0 || |
| user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) { |
| printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n", |
| r->cfg.avg, r->cfg.burst); |
| return false; |
| } |
| if (r->cfg.mode == 0 || |
| r->cfg.mode > (XT_HASHLIMIT_HASH_DPT | |
| XT_HASHLIMIT_HASH_DIP | |
| XT_HASHLIMIT_HASH_SIP | |
| XT_HASHLIMIT_HASH_SPT)) |
| return false; |
| if (!r->cfg.gc_interval) |
| return false; |
| if (!r->cfg.expire) |
| return false; |
| if (r->name[sizeof(r->name) - 1] != '\0') |
| return false; |
| |
| /* This is the best we've got: We cannot release and re-grab lock, |
| * since checkentry() is called before x_tables.c grabs xt_mutex. |
| * We also cannot grab the hashtable spinlock, since htable_create will |
| * call vmalloc, and that can sleep. And we cannot just re-search |
| * the list of htable's in htable_create(), since then we would |
| * create duplicate proc files. -HW */ |
| mutex_lock(&hlimit_mutex); |
| r->hinfo = htable_find_get(r->name, par->match->family); |
| if (!r->hinfo && htable_create_v0(r, par->match->family) != 0) { |
| mutex_unlock(&hlimit_mutex); |
| return false; |
| } |
| mutex_unlock(&hlimit_mutex); |
| |
| /* Ugly hack: For SMP, we only want to use one set */ |
| r->u.master = r; |
| return true; |
| } |
| |
| static bool hashlimit_mt_check(const struct xt_mtchk_param *par) |
| { |
| struct xt_hashlimit_mtinfo1 *info = par->matchinfo; |
| |
| /* Check for overflow. */ |
| if (info->cfg.burst == 0 || |
| user2credits(info->cfg.avg * info->cfg.burst) < |
| user2credits(info->cfg.avg)) { |
| printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n", |
| info->cfg.avg, info->cfg.burst); |
| return false; |
| } |
| if (info->cfg.gc_interval == 0 || info->cfg.expire == 0) |
| return false; |
| if (info->name[sizeof(info->name)-1] != '\0') |
| return false; |
| if (par->match->family == NFPROTO_IPV4) { |
| if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32) |
| return false; |
| } else { |
| if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128) |
| return false; |
| } |
| |
| /* This is the best we've got: We cannot release and re-grab lock, |
| * since checkentry() is called before x_tables.c grabs xt_mutex. |
| * We also cannot grab the hashtable spinlock, since htable_create will |
| * call vmalloc, and that can sleep. And we cannot just re-search |
| * the list of htable's in htable_create(), since then we would |
| * create duplicate proc files. -HW */ |
| mutex_lock(&hlimit_mutex); |
| info->hinfo = htable_find_get(info->name, par->match->family); |
| if (!info->hinfo && htable_create(info, par->match->family) != 0) { |
| mutex_unlock(&hlimit_mutex); |
| return false; |
| } |
| mutex_unlock(&hlimit_mutex); |
| return true; |
| } |
| |
| static void |
| hashlimit_mt_destroy_v0(const struct xt_match *match, void *matchinfo) |
| { |
| const struct xt_hashlimit_info *r = matchinfo; |
| |
| htable_put(r->hinfo); |
| } |
| |
| static void |
| hashlimit_mt_destroy(const struct xt_match *match, void *matchinfo) |
| { |
| const struct xt_hashlimit_mtinfo1 *info = matchinfo; |
| |
| htable_put(info->hinfo); |
| } |
| |
| #ifdef CONFIG_COMPAT |
| struct compat_xt_hashlimit_info { |
| char name[IFNAMSIZ]; |
| struct hashlimit_cfg cfg; |
| compat_uptr_t hinfo; |
| compat_uptr_t master; |
| }; |
| |
| static void hashlimit_mt_compat_from_user(void *dst, void *src) |
| { |
| int off = offsetof(struct compat_xt_hashlimit_info, hinfo); |
| |
| memcpy(dst, src, off); |
| memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off); |
| } |
| |
| static int hashlimit_mt_compat_to_user(void __user *dst, void *src) |
| { |
| int off = offsetof(struct compat_xt_hashlimit_info, hinfo); |
| |
| return copy_to_user(dst, src, off) ? -EFAULT : 0; |
| } |
| #endif |
| |
| static struct xt_match hashlimit_mt_reg[] __read_mostly = { |
| { |
| .name = "hashlimit", |
| .revision = 0, |
| .family = NFPROTO_IPV4, |
| .match = hashlimit_mt_v0, |
| .matchsize = sizeof(struct xt_hashlimit_info), |
| #ifdef CONFIG_COMPAT |
| .compatsize = sizeof(struct compat_xt_hashlimit_info), |
| .compat_from_user = hashlimit_mt_compat_from_user, |
| .compat_to_user = hashlimit_mt_compat_to_user, |
| #endif |
| .checkentry = hashlimit_mt_check_v0, |
| .destroy = hashlimit_mt_destroy_v0, |
| .me = THIS_MODULE |
| }, |
| { |
| .name = "hashlimit", |
| .revision = 1, |
| .family = NFPROTO_IPV4, |
| .match = hashlimit_mt, |
| .matchsize = sizeof(struct xt_hashlimit_mtinfo1), |
| .checkentry = hashlimit_mt_check, |
| .destroy = hashlimit_mt_destroy, |
| .me = THIS_MODULE, |
| }, |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| { |
| .name = "hashlimit", |
| .family = NFPROTO_IPV6, |
| .match = hashlimit_mt_v0, |
| .matchsize = sizeof(struct xt_hashlimit_info), |
| #ifdef CONFIG_COMPAT |
| .compatsize = sizeof(struct compat_xt_hashlimit_info), |
| .compat_from_user = hashlimit_mt_compat_from_user, |
| .compat_to_user = hashlimit_mt_compat_to_user, |
| #endif |
| .checkentry = hashlimit_mt_check_v0, |
| .destroy = hashlimit_mt_destroy_v0, |
| .me = THIS_MODULE |
| }, |
| { |
| .name = "hashlimit", |
| .revision = 1, |
| .family = NFPROTO_IPV6, |
| .match = hashlimit_mt, |
| .matchsize = sizeof(struct xt_hashlimit_mtinfo1), |
| .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 proc_dir_entry *pde = s->private; |
| struct xt_hashlimit_htable *htable = pde->data; |
| 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 proc_dir_entry *pde = s->private; |
| struct xt_hashlimit_htable *htable = pde->data; |
| unsigned int *bucket = (unsigned int *)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 proc_dir_entry *pde = s->private; |
| struct xt_hashlimit_htable *htable = pde->data; |
| unsigned int *bucket = (unsigned int *)v; |
| |
| kfree(bucket); |
| spin_unlock_bh(&htable->lock); |
| } |
| |
| static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family, |
| struct seq_file *s) |
| { |
| /* recalculate to show accurate numbers */ |
| rateinfo_recalc(ent, jiffies); |
| |
| switch (family) { |
| case NFPROTO_IPV4: |
| return seq_printf(s, "%ld %u.%u.%u.%u:%u->" |
| "%u.%u.%u.%u:%u %u %u %u\n", |
| (long)(ent->expires - jiffies)/HZ, |
| NIPQUAD(ent->dst.ip.src), |
| ntohs(ent->dst.src_port), |
| NIPQUAD(ent->dst.ip.dst), |
| ntohs(ent->dst.dst_port), |
| ent->rateinfo.credit, ent->rateinfo.credit_cap, |
| ent->rateinfo.cost); |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| case NFPROTO_IPV6: |
| return seq_printf(s, "%ld " NIP6_FMT ":%u->" |
| NIP6_FMT ":%u %u %u %u\n", |
| (long)(ent->expires - jiffies)/HZ, |
| NIP6(*(struct in6_addr *)&ent->dst.ip6.src), |
| ntohs(ent->dst.src_port), |
| NIP6(*(struct in6_addr *)&ent->dst.ip6.dst), |
| ntohs(ent->dst.dst_port), |
| ent->rateinfo.credit, ent->rateinfo.credit_cap, |
| ent->rateinfo.cost); |
| #endif |
| default: |
| BUG(); |
| return 0; |
| } |
| } |
| |
| static int dl_seq_show(struct seq_file *s, void *v) |
| { |
| struct proc_dir_entry *pde = s->private; |
| struct xt_hashlimit_htable *htable = pde->data; |
| unsigned int *bucket = (unsigned int *)v; |
| struct dsthash_ent *ent; |
| struct hlist_node *pos; |
| |
| if (!hlist_empty(&htable->hash[*bucket])) { |
| hlist_for_each_entry(ent, pos, &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 = { |
| .start = dl_seq_start, |
| .next = dl_seq_next, |
| .stop = dl_seq_stop, |
| .show = dl_seq_show |
| }; |
| |
| static int dl_proc_open(struct inode *inode, struct file *file) |
| { |
| int ret = seq_open(file, &dl_seq_ops); |
| |
| if (!ret) { |
| struct seq_file *sf = file->private_data; |
| sf->private = PDE(inode); |
| } |
| return ret; |
| } |
| |
| static const struct file_operations dl_file_ops = { |
| .owner = THIS_MODULE, |
| .open = dl_proc_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release |
| }; |
| |
| static int __init hashlimit_mt_init(void) |
| { |
| int 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) { |
| printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n"); |
| goto err2; |
| } |
| hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", init_net.proc_net); |
| if (!hashlimit_procdir4) { |
| printk(KERN_ERR "xt_hashlimit: unable to create proc dir " |
| "entry\n"); |
| goto err3; |
| } |
| err = 0; |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", init_net.proc_net); |
| if (!hashlimit_procdir6) { |
| printk(KERN_ERR "xt_hashlimit: unable to create proc dir " |
| "entry\n"); |
| err = -ENOMEM; |
| } |
| #endif |
| if (!err) |
| return 0; |
| remove_proc_entry("ipt_hashlimit", init_net.proc_net); |
| err3: |
| kmem_cache_destroy(hashlimit_cachep); |
| err2: |
| xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); |
| err1: |
| return err; |
| |
| } |
| |
| static void __exit hashlimit_mt_exit(void) |
| { |
| remove_proc_entry("ipt_hashlimit", init_net.proc_net); |
| #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| remove_proc_entry("ip6t_hashlimit", init_net.proc_net); |
| #endif |
| kmem_cache_destroy(hashlimit_cachep); |
| xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); |
| } |
| |
| module_init(hashlimit_mt_init); |
| module_exit(hashlimit_mt_exit); |