netfilter: ipset: hash:ip set type support

The module implements the hash:ip type support in four flavours:
for IPv4 or IPv6, both without and with timeout support.

All the hash types are based on the "array hash" or ahash structure
and functions as a good compromise between minimal memory footprint
and speed. The hashing uses arrays to resolve clashes. The hash table
is resized (doubled) when searching becomes too long. Resizing can be
triggered by userspace add commands only and those are serialized by
the nfnl mutex. During resizing the set is read-locked, so the only
possible concurrent operations are the kernel side readers. Those are
protected by RCU locking.

Because of the four flavours and the other hash types, the functions
are implemented in general forms in the ip_set_ahash.h header file
and the real functions are generated before compiling by macro expansion.
Thus the dereferencing of low-level functions and void pointer arguments
could be avoided: the low-level functions are inlined, the function
arguments are pointers of type-specific structures.
Signed-off-by: NJozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

include/linux/netfilter/ipset/ip_set_hash.h

+#ifndef __IP_SET_HASH_H
+#define __IP_SET_HASH_H
+
+/* Hash type specific error codes */
+enum {
+	/* Hash is full */
+	IPSET_ERR_HASH_FULL = IPSET_ERR_TYPE_SPECIFIC,
+	/* Null-valued element */
+	IPSET_ERR_HASH_ELEM,
+	/* Invalid protocol */
+	IPSET_ERR_INVALID_PROTO,
+	/* Protocol missing but must be specified */
+	IPSET_ERR_MISSING_PROTO,
+};
+
+#ifdef __KERNEL__
+
+#define IPSET_DEFAULT_HASHSIZE		1024
+#define IPSET_MIMINAL_HASHSIZE		64
+#define IPSET_DEFAULT_MAXELEM		65536
+#define IPSET_DEFAULT_PROBES		4
+#define IPSET_DEFAULT_RESIZE		100
+
+#endif /* __KERNEL__ */
+
+#endif /* __IP_SET_HASH_H */

net/netfilter/ipset/Kconfig

@@ -50,4 +50,14 @@ config IP_SET_BITMAP_PORT
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config IP_SET_HASH_IP
+	tristate "hash:ip set support"
+	depends on IP_SET
+	help
+	  This option adds the hash:ip set type support, by which one
+	  can store arbitrary IPv4 or IPv6 addresses (or network addresses)
+	  in a set.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 endif # IP_SET

net/netfilter/ipset/Makefile

@@ -11,3 +11,6 @@ obj-$(CONFIG_IP_SET) += ip_set.o
 obj-$(CONFIG_IP_SET_BITMAP_IP) += ip_set_bitmap_ip.o
 obj-$(CONFIG_IP_SET_BITMAP_IPMAC) += ip_set_bitmap_ipmac.o
 obj-$(CONFIG_IP_SET_BITMAP_PORT) += ip_set_bitmap_port.o
+
+# hash types
+obj-$(CONFIG_IP_SET_HASH_IP) += ip_set_hash_ip.o

net/netfilter/ipset/ip_set_hash_ip.c

+/* Copyright (C) 2003-2011 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/* Kernel module implementing an IP set type: the hash:ip type */
+
+#include <linux/jhash.h>
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/skbuff.h>
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/spinlock.h>
+#include <linux/random.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/netlink.h>
+#include <net/tcp.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/ipset/pfxlen.h>
+#include <linux/netfilter/ipset/ip_set.h>
+#include <linux/netfilter/ipset/ip_set_timeout.h>
+#include <linux/netfilter/ipset/ip_set_hash.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
+MODULE_DESCRIPTION("hash:ip type of IP sets");
+MODULE_ALIAS("ip_set_hash:ip");
+
+/* Type specific function prefix */
+#define TYPE		hash_ip
+
+static bool
+hash_ip_same_set(const struct ip_set *a, const struct ip_set *b);
+
+#define hash_ip4_same_set	hash_ip_same_set
+#define hash_ip6_same_set	hash_ip_same_set
+
+/* The type variant functions: IPv4 */
+
+/* Member elements without timeout */
+struct hash_ip4_elem {
+	__be32 ip;
+};
+
+/* Member elements with timeout support */
+struct hash_ip4_telem {
+	__be32 ip;
+	unsigned long timeout;
+};
+
+static inline bool
+hash_ip4_data_equal(const struct hash_ip4_elem *ip1,
+		    const struct hash_ip4_elem *ip2)
+{
+	return ip1->ip == ip2->ip;
+}
+
+static inline bool
+hash_ip4_data_isnull(const struct hash_ip4_elem *elem)
+{
+	return elem->ip == 0;
+}
+
+static inline void
+hash_ip4_data_copy(struct hash_ip4_elem *dst, const struct hash_ip4_elem *src)
+{
+	dst->ip = src->ip;
+}
+
+/* Zero valued IP addresses cannot be stored */
+static inline void
+hash_ip4_data_zero_out(struct hash_ip4_elem *elem)
+{
+	elem->ip = 0;
+}
+
+static inline bool
+hash_ip4_data_list(struct sk_buff *skb, const struct hash_ip4_elem *data)
+{
+	NLA_PUT_IPADDR4(skb, IPSET_ATTR_IP, data->ip);
+	return 0;
+
+nla_put_failure:
+	return 1;
+}
+
+static bool
+hash_ip4_data_tlist(struct sk_buff *skb, const struct hash_ip4_elem *data)
+{
+	const struct hash_ip4_telem *tdata =
+		(const struct hash_ip4_telem *)data;
+
+	NLA_PUT_IPADDR4(skb, IPSET_ATTR_IP, tdata->ip);
+	NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT,
+		      htonl(ip_set_timeout_get(tdata->timeout)));
+
+	return 0;
+
+nla_put_failure:
+	return 1;
+}
+
+#define IP_SET_HASH_WITH_NETMASK
+#define PF		4
+#define HOST_MASK	32
+#include <linux/netfilter/ipset/ip_set_ahash.h>
+
+static int
+hash_ip4_kadt(struct ip_set *set, const struct sk_buff *skb,
+	      enum ipset_adt adt, u8 pf, u8 dim, u8 flags)
+{
+	const struct ip_set_hash *h = set->data;
+	ipset_adtfn adtfn = set->variant->adt[adt];
+	__be32 ip;
+
+	ip4addrptr(skb, flags & IPSET_DIM_ONE_SRC, &ip);
+	ip &= ip_set_netmask(h->netmask);
+	if (ip == 0)
+		return -EINVAL;
+
+	return adtfn(set, &ip, h->timeout);
+}
+
+static int
+hash_ip4_uadt(struct ip_set *set, struct nlattr *tb[],
+	      enum ipset_adt adt, u32 *lineno, u32 flags)
+{
+	const struct ip_set_hash *h = set->data;
+	ipset_adtfn adtfn = set->variant->adt[adt];
+	u32 ip, ip_to, hosts, timeout = h->timeout;
+	__be32 nip;
+	int ret = 0;
+
+	if (unlikely(!tb[IPSET_ATTR_IP] ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT)))
+		return -IPSET_ERR_PROTOCOL;
+
+	if (tb[IPSET_ATTR_LINENO])
+		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
+
+	ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP], &ip);
+	if (ret)
+		return ret;
+
+	ip &= ip_set_hostmask(h->netmask);
+
+	if (tb[IPSET_ATTR_TIMEOUT]) {
+		if (!with_timeout(h->timeout))
+			return -IPSET_ERR_TIMEOUT;
+		timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
+	}
+
+	if (adt == IPSET_TEST) {
+		nip = htonl(ip);
+		if (nip == 0)
+			return -IPSET_ERR_HASH_ELEM;
+		return adtfn(set, &nip, timeout);
+	}
+
+	if (tb[IPSET_ATTR_IP_TO]) {
+		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
+		if (ret)
+			return ret;
+		if (ip > ip_to)
+			swap(ip, ip_to);
+	} else if (tb[IPSET_ATTR_CIDR]) {
+		u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
+
+		if (cidr > 32)
+			return -IPSET_ERR_INVALID_CIDR;
+		ip &= ip_set_hostmask(cidr);
+		ip_to = ip | ~ip_set_hostmask(cidr);
+	} else
+		ip_to = ip;
+
+	hosts = h->netmask == 32 ? 1 : 2 << (32 - h->netmask - 1);
+
+	for (; !before(ip_to, ip); ip += hosts) {
+		nip = htonl(ip);
+		if (nip == 0)
+			return -IPSET_ERR_HASH_ELEM;
+		ret = adtfn(set, &nip, timeout);
+
+		if (ret && !ip_set_eexist(ret, flags))
+			return ret;
+		else
+			ret = 0;
+	}
+	return ret;
+}
+
+static bool
+hash_ip_same_set(const struct ip_set *a, const struct ip_set *b)
+{
+	const struct ip_set_hash *x = a->data;
+	const struct ip_set_hash *y = b->data;
+
+	/* Resizing changes htable_bits, so we ignore it */
+	return x->maxelem == y->maxelem &&
+	       x->timeout == y->timeout &&
+	       x->netmask == y->netmask;
+}
+
+/* The type variant functions: IPv6 */
+
+struct hash_ip6_elem {
+	union nf_inet_addr ip;
+};
+
+struct hash_ip6_telem {
+	union nf_inet_addr ip;
+	unsigned long timeout;
+};
+
+static inline bool
+hash_ip6_data_equal(const struct hash_ip6_elem *ip1,
+		    const struct hash_ip6_elem *ip2)
+{
+	return ipv6_addr_cmp(&ip1->ip.in6, &ip2->ip.in6) == 0;
+}
+
+static inline bool
+hash_ip6_data_isnull(const struct hash_ip6_elem *elem)
+{
+	return ipv6_addr_any(&elem->ip.in6);
+}
+
+static inline void
+hash_ip6_data_copy(struct hash_ip6_elem *dst, const struct hash_ip6_elem *src)
+{
+	ipv6_addr_copy(&dst->ip.in6, &src->ip.in6);
+}
+
+static inline void
+hash_ip6_data_zero_out(struct hash_ip6_elem *elem)
+{
+	ipv6_addr_set(&elem->ip.in6, 0, 0, 0, 0);
+}
+
+static inline void
+ip6_netmask(union nf_inet_addr *ip, u8 prefix)
+{
+	ip->ip6[0] &= ip_set_netmask6(prefix)[0];
+	ip->ip6[1] &= ip_set_netmask6(prefix)[1];
+	ip->ip6[2] &= ip_set_netmask6(prefix)[2];
+	ip->ip6[3] &= ip_set_netmask6(prefix)[3];
+}
+
+static bool
+hash_ip6_data_list(struct sk_buff *skb, const struct hash_ip6_elem *data)
+{
+	NLA_PUT_IPADDR6(skb, IPSET_ATTR_IP, &data->ip);
+	return 0;
+
+nla_put_failure:
+	return 1;
+}
+
+static bool
+hash_ip6_data_tlist(struct sk_buff *skb, const struct hash_ip6_elem *data)
+{
+	const struct hash_ip6_telem *e =
+		(const struct hash_ip6_telem *)data;
+
+	NLA_PUT_IPADDR6(skb, IPSET_ATTR_IP, &e->ip);
+	NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT,
+		      htonl(ip_set_timeout_get(e->timeout)));
+	return 0;
+
+nla_put_failure:
+	return 1;
+}
+
+#undef PF
+#undef HOST_MASK
+
+#define PF		6
+#define HOST_MASK	128
+#include <linux/netfilter/ipset/ip_set_ahash.h>
+
+static int
+hash_ip6_kadt(struct ip_set *set, const struct sk_buff *skb,
+	      enum ipset_adt adt, u8 pf, u8 dim, u8 flags)
+{
+	const struct ip_set_hash *h = set->data;
+	ipset_adtfn adtfn = set->variant->adt[adt];
+	union nf_inet_addr ip;
+
+	ip6addrptr(skb, flags & IPSET_DIM_ONE_SRC, &ip.in6);
+	ip6_netmask(&ip, h->netmask);
+	if (ipv6_addr_any(&ip.in6))
+		return -EINVAL;
+
+	return adtfn(set, &ip, h->timeout);
+}
+
+static const struct nla_policy hash_ip6_adt_policy[IPSET_ATTR_ADT_MAX + 1] = {
+	[IPSET_ATTR_IP]		= { .type = NLA_NESTED },
+	[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
+	[IPSET_ATTR_LINENO]	= { .type = NLA_U32 },
+};
+
+static int
+hash_ip6_uadt(struct ip_set *set, struct nlattr *tb[],
+	      enum ipset_adt adt, u32 *lineno, u32 flags)
+{
+	const struct ip_set_hash *h = set->data;
+	ipset_adtfn adtfn = set->variant->adt[adt];
+	union nf_inet_addr ip;
+	u32 timeout = h->timeout;
+	int ret;
+
+	if (unlikely(!tb[IPSET_ATTR_IP] ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
+		     tb[IPSET_ATTR_IP_TO] ||
+		     tb[IPSET_ATTR_CIDR]))
+		return -IPSET_ERR_PROTOCOL;
+
+	if (tb[IPSET_ATTR_LINENO])
+		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
+
+	ret = ip_set_get_ipaddr6(tb[IPSET_ATTR_IP], &ip);
+	if (ret)
+		return ret;
+
+	ip6_netmask(&ip, h->netmask);
+	if (ipv6_addr_any(&ip.in6))
+		return -IPSET_ERR_HASH_ELEM;
+
+	if (tb[IPSET_ATTR_TIMEOUT]) {
+		if (!with_timeout(h->timeout))
+			return -IPSET_ERR_TIMEOUT;
+		timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
+	}
+
+	ret = adtfn(set, &ip, timeout);
+
+	return ip_set_eexist(ret, flags) ? 0 : ret;
+}
+
+/* Create hash:ip type of sets */
+
+static int
+hash_ip_create(struct ip_set *set, struct nlattr *tb[], u32 flags)
+{
+	u32 hashsize = IPSET_DEFAULT_HASHSIZE, maxelem = IPSET_DEFAULT_MAXELEM;
+	u8 netmask, hbits;
+	struct ip_set_hash *h;
+
+	if (!(set->family == AF_INET || set->family == AF_INET6))
+		return -IPSET_ERR_INVALID_FAMILY;
+	netmask = set->family == AF_INET ? 32 : 128;
+	pr_debug("Create set %s with family %s\n",
+		 set->name, set->family == AF_INET ? "inet" : "inet6");
+
+	if (unlikely(!ip_set_optattr_netorder(tb, IPSET_ATTR_HASHSIZE) ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_MAXELEM) ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT)))
+		return -IPSET_ERR_PROTOCOL;
+
+	if (tb[IPSET_ATTR_HASHSIZE]) {
+		hashsize = ip_set_get_h32(tb[IPSET_ATTR_HASHSIZE]);
+		if (hashsize < IPSET_MIMINAL_HASHSIZE)
+			hashsize = IPSET_MIMINAL_HASHSIZE;
+	}
+
+	if (tb[IPSET_ATTR_MAXELEM])
+		maxelem = ip_set_get_h32(tb[IPSET_ATTR_MAXELEM]);
+
+	if (tb[IPSET_ATTR_NETMASK]) {
+		netmask = nla_get_u8(tb[IPSET_ATTR_NETMASK]);
+
+		if ((set->family == AF_INET && netmask > 32) ||
+		    (set->family == AF_INET6 && netmask > 128) ||
+		    netmask == 0)
+			return -IPSET_ERR_INVALID_NETMASK;
+	}
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return -ENOMEM;
+
+	h->maxelem = maxelem;
+	h->netmask = netmask;
+	get_random_bytes(&h->initval, sizeof(h->initval));
+	h->timeout = IPSET_NO_TIMEOUT;
+
+	hbits = htable_bits(hashsize);
+	h->table = ip_set_alloc(
+			sizeof(struct htable)
+			+ jhash_size(hbits) * sizeof(struct hbucket));
+	if (!h->table) {
+		kfree(h);
+		return -ENOMEM;
+	}
+	h->table->htable_bits = hbits;
+
+	set->data = h;
+
+	if (tb[IPSET_ATTR_TIMEOUT]) {
+		h->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
+
+		set->variant = set->family == AF_INET
+			? &hash_ip4_tvariant : &hash_ip6_tvariant;
+
+		if (set->family == AF_INET)
+			hash_ip4_gc_init(set);
+		else
+			hash_ip6_gc_init(set);
+	} else {
+		set->variant = set->family == AF_INET
+			? &hash_ip4_variant : &hash_ip6_variant;
+	}
+
+	pr_debug("create %s hashsize %u (%u) maxelem %u: %p(%p)\n",
+		 set->name, jhash_size(h->table->htable_bits),
+		 h->table->htable_bits, h->maxelem, set->data, h->table);
+
+	return 0;
+}
+
+static struct ip_set_type hash_ip_type __read_mostly = {
+	.name		= "hash:ip",
+	.protocol	= IPSET_PROTOCOL,
+	.features	= IPSET_TYPE_IP,
+	.dimension	= IPSET_DIM_ONE,
+	.family		= AF_UNSPEC,
+	.revision	= 0,
+	.create		= hash_ip_create,
+	.create_policy	= {
+		[IPSET_ATTR_HASHSIZE]	= { .type = NLA_U32 },
+		[IPSET_ATTR_MAXELEM]	= { .type = NLA_U32 },
+		[IPSET_ATTR_PROBES]	= { .type = NLA_U8 },
+		[IPSET_ATTR_RESIZE]	= { .type = NLA_U8  },
+		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
+		[IPSET_ATTR_NETMASK]	= { .type = NLA_U8  },
+	},
+	.adt_policy	= {
+		[IPSET_ATTR_IP]		= { .type = NLA_NESTED },
+		[IPSET_ATTR_IP_TO]	= { .type = NLA_NESTED },
+		[IPSET_ATTR_CIDR]	= { .type = NLA_U8 },
+		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
+		[IPSET_ATTR_LINENO]	= { .type = NLA_U32 },
+	},
+	.me		= THIS_MODULE,
+};
+
+static int __init
+hash_ip_init(void)
+{
+	return ip_set_type_register(&hash_ip_type);
+}
+
+static void __exit
+hash_ip_fini(void)
+{
+	ip_set_type_unregister(&hash_ip_type);
+}
+
+module_init(hash_ip_init);
+module_exit(hash_ip_fini);