[PATCH 12/13] list:set set type support

[Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>]

The module implements the list:set type support in two flavours:
without and with timeout. The sets has two sides: for the userspace,
they store the names of other (non list:set type of) sets: one can add,
delete and test set names. For the kernel, it forms an ordered union of
the member sets: the members sets are tried in order when elements are
added, deleted and tested and the process stops at the first success.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
---
 include/linux/netfilter/ipset/ip_set_list.h |   27 ++
 net/netfilter/ipset/Kconfig                 |   10 +
 net/netfilter/ipset/Makefile                |    3 +
 net/netfilter/ipset/ip_set_list_set.c       |  584 +++++++++++++++++++++++++++
 4 files changed, 624 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/netfilter/ipset/ip_set_list.h
 create mode 100644 net/netfilter/ipset/ip_set_list_set.c

diff --git a/include/linux/netfilter/ipset/ip_set_list.h b/include/linux/netfilter/ipset/ip_set_list.h
new file mode 100644
index 0000000..40a63f3
--- /dev/null
+++ b/include/linux/netfilter/ipset/ip_set_list.h
@@ -0,0 +1,27 @@
+#ifndef __IP_SET_LIST_H
+#define __IP_SET_LIST_H
+
+/* List type specific error codes */
+enum {
+	/* Set name to be added/deleted/tested does not exist. */
+	IPSET_ERR_NAME = IPSET_ERR_TYPE_SPECIFIC,
+	/* list:set type is not permitted to add */
+	IPSET_ERR_LOOP,
+	/* Missing reference set */
+	IPSET_ERR_BEFORE,
+	/* Reference set does not exist */
+	IPSET_ERR_NAMEREF,
+	/* Set is full */
+	IPSET_ERR_LIST_FULL,
+	/* Reference set is not added to the set */
+	IPSET_ERR_REF_EXIST,
+};
+
+#ifdef __KERNEL__
+
+#define IP_SET_LIST_DEFAULT_SIZE	8
+#define IP_SET_LIST_MIN_SIZE		4
+
+#endif /* __KERNEL__ */
+
+#endif /* __IP_SET_LIST_H */
diff --git a/net/netfilter/ipset/Kconfig b/net/netfilter/ipset/Kconfig
index 2512e7b..3b970d3 100644
--- a/net/netfilter/ipset/Kconfig
+++ b/net/netfilter/ipset/Kconfig
@@ -108,4 +108,14 @@ config IP_SET_HASH_NETPORT
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config IP_SET_LIST_SET
+	tristate "list:set set support"
+	depends on IP_SET
+	help
+	  This option adds the list:set set type support. In this
+	  kind of set one can store the name of other sets and it forms
+	  an ordered union of the member sets.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 endif # IP_SET
diff --git a/net/netfilter/ipset/Makefile b/net/netfilter/ipset/Makefile
index fbbebd6..5adbdab 100644
--- a/net/netfilter/ipset/Makefile
+++ b/net/netfilter/ipset/Makefile
@@ -19,3 +19,6 @@ obj-$(CONFIG_IP_SET_HASH_IPPORTIP) += ip_set_hash_ipportip.o
 obj-$(CONFIG_IP_SET_HASH_IPPORTNET) += ip_set_hash_ipportnet.o
 obj-$(CONFIG_IP_SET_HASH_NET) += ip_set_hash_net.o
 obj-$(CONFIG_IP_SET_HASH_NETPORT) += ip_set_hash_netport.o
+
+# list types
+obj-$(CONFIG_IP_SET_LIST_SET) += ip_set_list_set.o
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
new file mode 100644
index 0000000..a47c329
--- /dev/null
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -0,0 +1,584 @@
+/* Copyright (C) 2008-2011 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 list:set type */
+
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/skbuff.h>
+#include <linux/errno.h>
+
+#include <linux/netfilter/ipset/ip_set.h>
+#include <linux/netfilter/ipset/ip_set_timeout.h>
+#include <linux/netfilter/ipset/ip_set_list.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
+MODULE_DESCRIPTION("list:set type of IP sets");
+MODULE_ALIAS("ip_set_list:set");
+
+/* Member elements without and with timeout */
+struct set_elem {
+	ip_set_id_t id;
+};
+
+struct set_telem {
+	ip_set_id_t id;
+	unsigned long timeout;
+};
+
+/* Type structure */
+struct list_set {
+	size_t dsize;		/* element size */
+	u32 size;		/* size of set list array */
+	u32 timeout;		/* timeout value */
+	struct timer_list gc;	/* garbage collection */
+	struct set_elem members[0]; /* the set members */
+};
+
+static inline struct set_elem *
+list_set_elem(const struct list_set *map, u32 id)
+{
+	return (struct set_elem *)((char *)map->members + id * map->dsize);
+}
+
+static inline bool
+list_set_timeout(const struct list_set *map, u32 id)
+{
+	const struct set_telem *elem =
+		(const struct set_telem *) list_set_elem(map, id);
+
+	return ip_set_timeout_test(elem->timeout);
+}
+
+static inline bool
+list_set_expired(const struct list_set *map, u32 id)
+{
+	const struct set_telem *elem =
+		(const struct set_telem *) list_set_elem(map, id);
+
+	return ip_set_timeout_expired(elem->timeout);
+}
+
+static inline int
+list_set_exist(const struct set_telem *elem)
+{
+	return elem->id != IPSET_INVALID_ID &&
+	       !ip_set_timeout_expired(elem->timeout);
+}
+
+/* Set list without and with timeout */
+
+static int
+list_set_kadt(struct ip_set *set, const struct sk_buff *skb,
+	      enum ipset_adt adt, u8 pf, u8 dim, u8 flags)
+{
+	struct list_set *map = set->data;
+	struct set_elem *elem;
+	u32 i;
+	int ret;
+
+	for (i = 0; i < map->size; i++) {
+		elem = list_set_elem(map, i);
+		if (elem->id == IPSET_INVALID_ID)
+			return 0;
+		if (with_timeout(map->timeout) && list_set_expired(map, i))
+			continue;
+		switch (adt) {
+		case IPSET_TEST:
+			ret = ip_set_test(elem->id, skb, pf, dim, flags);
+			if (ret > 0)
+				return ret;
+			break;
+		case IPSET_ADD:
+			ret = ip_set_add(elem->id, skb, pf, dim, flags);
+			if (ret == 0)
+				return ret;
+			break;
+		case IPSET_DEL:
+			ret = ip_set_del(elem->id, skb, pf, dim, flags);
+			if (ret == 0)
+				return ret;
+			break;
+		default:
+			break;
+		}
+	}
+	return -EINVAL;
+}
+
+static bool
+next_id_eq(const struct list_set *map, u32 i, ip_set_id_t id)
+{
+	const struct set_elem *elem;
+
+	if (i + 1 < map->size) {
+		elem = list_set_elem(map, i + 1);
+		return !!(elem->id == id &&
+			  !(with_timeout(map->timeout) &&
+			    list_set_expired(map, i + 1)));
+	}
+
+	return 0;
+}
+
+static void
+list_elem_add(struct list_set *map, u32 i, ip_set_id_t id)
+{
+	struct set_elem *e;
+
+	for (; i < map->size; i++) {
+		e = list_set_elem(map, i);
+		swap(e->id, id);
+		if (e->id == IPSET_INVALID_ID)
+			break;
+	}
+}
+
+static void
+list_elem_tadd(struct list_set *map, u32 i, ip_set_id_t id,
+	       unsigned long timeout)
+{
+	struct set_telem *e;
+
+	for (; i < map->size; i++) {
+		e = (struct set_telem *)list_set_elem(map, i);
+		swap(e->id, id);
+		if (e->id == IPSET_INVALID_ID)
+			break;
+		swap(e->timeout, timeout);
+	}
+}
+
+static int
+list_set_add(struct list_set *map, u32 i, ip_set_id_t id,
+	     unsigned long timeout)
+{
+	const struct set_elem *e = list_set_elem(map, i);
+
+	if (i == map->size - 1 && e->id != IPSET_INVALID_ID)
+		/* Last element replaced: e.g. add new,before,last */
+		ip_set_put_byindex(e->id);
+	if (with_timeout(map->timeout))
+		list_elem_tadd(map, i, id, timeout);
+	else
+		list_elem_add(map, i, id);
+
+	return 0;
+}
+
+static int
+list_set_del(struct list_set *map, ip_set_id_t id, u32 i)
+{
+	struct set_elem *a = list_set_elem(map, i), *b;
+
+	ip_set_put_byindex(id);
+
+	for (; i < map->size - 1; i++) {
+		b = list_set_elem(map, i + 1);
+		a->id = b->id;
+		if (with_timeout(map->timeout))
+			((struct set_telem *)a)->timeout =
+				((struct set_telem *)b)->timeout;
+		a = b;
+		if (a->id == IPSET_INVALID_ID)
+			break;
+	}
+	/* Last element */
+	a->id = IPSET_INVALID_ID;
+	return 0;
+}
+
+static int
+list_set_uadt(struct ip_set *set, struct nlattr *tb[],
+	      enum ipset_adt adt, u32 *lineno, u32 flags)
+{
+	struct list_set *map = set->data;
+	bool with_timeout = with_timeout(map->timeout);
+	int before = 0;
+	u32 timeout = map->timeout;
+	ip_set_id_t id, refid = IPSET_INVALID_ID;
+	const struct set_elem *elem;
+	struct ip_set *s;
+	u32 i;
+	int ret = 0;
+
+	if (unlikely(!tb[IPSET_ATTR_NAME] ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS)))
+		return -IPSET_ERR_PROTOCOL;
+
+	if (tb[IPSET_ATTR_LINENO])
+		*lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
+
+	id = ip_set_get_byname(nla_data(tb[IPSET_ATTR_NAME]), &s);
+	if (id == IPSET_INVALID_ID)
+		return -IPSET_ERR_NAME;
+	/* "Loop detection" */
+	if (s->type->features & IPSET_TYPE_NAME) {
+		ret = -IPSET_ERR_LOOP;
+		goto finish;
+	}
+
+	if (tb[IPSET_ATTR_CADT_FLAGS]) {
+		u32 f = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);
+		before = f & IPSET_FLAG_BEFORE;
+	}
+
+	if (before && !tb[IPSET_ATTR_NAMEREF]) {
+		ret = -IPSET_ERR_BEFORE;
+		goto finish;
+	}
+
+	if (tb[IPSET_ATTR_NAMEREF]) {
+		refid = ip_set_get_byname(nla_data(tb[IPSET_ATTR_NAMEREF]),
+					  &s);
+		if (refid == IPSET_INVALID_ID) {
+			ret = -IPSET_ERR_NAMEREF;
+			goto finish;
+		}
+		if (!before)
+			before = -1;
+	}
+	if (tb[IPSET_ATTR_TIMEOUT]) {
+		if (!with_timeout) {
+			ret = -IPSET_ERR_TIMEOUT;
+			goto finish;
+		}
+		timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
+	}
+
+	switch (adt) {
+	case IPSET_TEST:
+		for (i = 0; i < map->size && !ret; i++) {
+			elem = list_set_elem(map, i);
+			if (elem->id == IPSET_INVALID_ID ||
+			    (before != 0 && i + 1 >= map->size))
+				break;
+			else if (with_timeout && list_set_expired(map, i))
+				continue;
+			else if (before > 0 && elem->id == id)
+				ret = next_id_eq(map, i, refid);
+			else if (before < 0 && elem->id == refid)
+				ret = next_id_eq(map, i, id);
+			else if (before == 0 && elem->id == id)
+				ret = 1;
+		}
+		break;
+	case IPSET_ADD:
+		for (i = 0; i < map->size && !ret; i++) {
+			elem = list_set_elem(map, i);
+			if (elem->id == id &&
+			    !(with_timeout && list_set_expired(map, i)))
+				ret = -IPSET_ERR_EXIST;
+		}
+		if (ret == -IPSET_ERR_EXIST)
+			break;
+		ret = -IPSET_ERR_LIST_FULL;
+		for (i = 0; i < map->size && ret == -IPSET_ERR_LIST_FULL; i++) {
+			elem = list_set_elem(map, i);
+			if (elem->id == IPSET_INVALID_ID)
+				ret = before != 0 ? -IPSET_ERR_REF_EXIST
+					: list_set_add(map, i, id, timeout);
+			else if (elem->id != refid)
+				continue;
+			else if (with_timeout && list_set_expired(map, i))
+				ret = -IPSET_ERR_REF_EXIST;
+			else if (before)
+				ret = list_set_add(map, i, id, timeout);
+			else if (i + 1 < map->size)
+				ret = list_set_add(map, i + 1, id, timeout);
+		}
+		break;
+	case IPSET_DEL:
+		ret = -IPSET_ERR_EXIST;
+		for (i = 0; i < map->size && ret == -IPSET_ERR_EXIST; i++) {
+			elem = list_set_elem(map, i);
+			if (elem->id == IPSET_INVALID_ID) {
+				ret = before != 0 ? -IPSET_ERR_REF_EXIST
+						  : -IPSET_ERR_EXIST;
+				break;
+			} else if (with_timeout && list_set_expired(map, i))
+				continue;
+			else if (elem->id == id &&
+				 (before == 0 ||
+				  (before > 0 &&
+				   next_id_eq(map, i, refid))))
+				ret = list_set_del(map, id, i);
+			else if (before < 0 &&
+				 elem->id == refid &&
+				 next_id_eq(map, i, id))
+				ret = list_set_del(map, id, i + 1);
+		}
+		break;
+	default:
+		break;
+	}
+
+finish:
+	if (refid != IPSET_INVALID_ID)
+		ip_set_put_byindex(refid);
+	if (adt != IPSET_ADD || ret)
+		ip_set_put_byindex(id);
+
+	return ip_set_eexist(ret, flags) ? 0 : ret;
+}
+
+static void
+list_set_flush(struct ip_set *set)
+{
+	struct list_set *map = set->data;
+	struct set_elem *elem;
+	u32 i;
+
+	for (i = 0; i < map->size; i++) {
+		elem = list_set_elem(map, i);
+		if (elem->id != IPSET_INVALID_ID) {
+			ip_set_put_byindex(elem->id);
+			elem->id = IPSET_INVALID_ID;
+		}
+	}
+}
+
+static void
+list_set_destroy(struct ip_set *set)
+{
+	struct list_set *map = set->data;
+
+	if (with_timeout(map->timeout))
+		del_timer_sync(&map->gc);
+	list_set_flush(set);
+	kfree(map);
+
+	set->data = NULL;
+}
+
+static int
+list_set_head(struct ip_set *set, struct sk_buff *skb)
+{
+	const struct list_set *map = set->data;
+	struct nlattr *nested;
+
+	nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
+	if (!nested)
+		goto nla_put_failure;
+	NLA_PUT_NET32(skb, IPSET_ATTR_SIZE, htonl(map->size));
+	if (with_timeout(map->timeout))
+		NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT, htonl(map->timeout));
+	NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
+		      htonl(atomic_read(&set->ref) - 1));
+	NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE,
+		      htonl(sizeof(*map) + map->size * map->dsize));
+	ipset_nest_end(skb, nested);
+
+	return 0;
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
+static int
+list_set_list(const struct ip_set *set,
+	      struct sk_buff *skb, struct netlink_callback *cb)
+{
+	const struct list_set *map = set->data;
+	struct nlattr *atd, *nested;
+	u32 i, first = cb->args[2];
+	const struct set_elem *e;
+
+	atd = ipset_nest_start(skb, IPSET_ATTR_ADT);
+	if (!atd)
+		return -EMSGSIZE;
+	for (; cb->args[2] < map->size; cb->args[2]++) {
+		i = cb->args[2];
+		e = list_set_elem(map, i);
+		if (e->id == IPSET_INVALID_ID)
+			goto finish;
+		if (with_timeout(map->timeout) && list_set_expired(map, i))
+			continue;
+		nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
+		if (!nested) {
+			if (i == first) {
+				nla_nest_cancel(skb, atd);
+				return -EMSGSIZE;
+			} else
+				goto nla_put_failure;
+		}
+		NLA_PUT_STRING(skb, IPSET_ATTR_NAME,
+			       ip_set_name_byindex(e->id));
+		if (with_timeout(map->timeout)) {
+			const struct set_telem *te =
+				(const struct set_telem *) e;
+			NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT,
+				      htonl(ip_set_timeout_get(te->timeout)));
+		}
+		ipset_nest_end(skb, nested);
+	}
+finish:
+	ipset_nest_end(skb, atd);
+	/* Set listing finished */
+	cb->args[2] = 0;
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, nested);
+	ipset_nest_end(skb, atd);
+	if (unlikely(i == first)) {
+		cb->args[2] = 0;
+		return -EMSGSIZE;
+	}
+	return 0;
+}
+
+static bool
+list_set_same_set(const struct ip_set *a, const struct ip_set *b)
+{
+	const struct list_set *x = a->data;
+	const struct list_set *y = b->data;
+
+	return x->size == y->size &&
+	       x->timeout == y->timeout;
+}
+
+static const struct ip_set_type_variant list_set = {
+	.kadt	= list_set_kadt,
+	.uadt	= list_set_uadt,
+	.destroy = list_set_destroy,
+	.flush	= list_set_flush,
+	.head	= list_set_head,
+	.list	= list_set_list,
+	.same_set = list_set_same_set,
+};
+
+static void
+list_set_gc(unsigned long ul_set)
+{
+	struct ip_set *set = (struct ip_set *) ul_set;
+	struct list_set *map = set->data;
+	struct set_telem *e;
+	u32 i;
+
+	/* We run parallel with other readers (test element)
+	 * but adding/deleting new entries is locked out */
+	read_lock_bh(&set->lock);
+	for (i = map->size - 1; i >= 0; i--) {
+		e = (struct set_telem *) list_set_elem(map, i);
+		if (e->id != IPSET_INVALID_ID &&
+		    list_set_expired(map, i))
+			list_set_del(map, e->id, i);
+	}
+	read_unlock_bh(&set->lock);
+
+	map->gc.expires = jiffies + IPSET_GC_PERIOD(map->timeout) * HZ;
+	add_timer(&map->gc);
+}
+
+static void
+list_set_gc_init(struct ip_set *set)
+{
+	struct list_set *map = set->data;
+
+	init_timer(&map->gc);
+	map->gc.data = (unsigned long) set;
+	map->gc.function = list_set_gc;
+	map->gc.expires = jiffies + IPSET_GC_PERIOD(map->timeout) * HZ;
+	add_timer(&map->gc);
+}
+
+/* Create list:set type of sets */
+
+static bool
+init_list_set(struct ip_set *set, u32 size, size_t dsize,
+	      unsigned long timeout)
+{
+	struct list_set *map;
+	struct set_elem *e;
+	u32 i;
+
+	map = kzalloc(sizeof(*map) + size * dsize, GFP_KERNEL);
+	if (!map)
+		return false;
+
+	map->size = size;
+	map->dsize = dsize;
+	map->timeout = timeout;
+	set->data = map;
+
+	for (i = 0; i < size; i++) {
+		e = list_set_elem(map, i);
+		e->id = IPSET_INVALID_ID;
+	}
+
+	return true;
+}
+
+static int
+list_set_create(struct ip_set *set, struct nlattr *tb[], u32 flags)
+{
+	u32 size = IP_SET_LIST_DEFAULT_SIZE;
+
+	if (unlikely(!ip_set_optattr_netorder(tb, IPSET_ATTR_SIZE) ||
+		     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT)))
+		return -IPSET_ERR_PROTOCOL;
+
+	if (tb[IPSET_ATTR_SIZE])
+		size = ip_set_get_h32(tb[IPSET_ATTR_SIZE]);
+	if (size < IP_SET_LIST_MIN_SIZE)
+		size = IP_SET_LIST_MIN_SIZE;
+
+	if (tb[IPSET_ATTR_TIMEOUT]) {
+		if (!init_list_set(set, size, sizeof(struct set_telem),
+				   ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT])))
+			return -ENOMEM;
+
+		list_set_gc_init(set);
+	} else {
+		if (!init_list_set(set, size, sizeof(struct set_elem),
+				   IPSET_NO_TIMEOUT))
+			return -ENOMEM;
+	}
+	set->variant = &list_set;
+	return 0;
+}
+
+static struct ip_set_type list_set_type __read_mostly = {
+	.name		= "list:set",
+	.protocol	= IPSET_PROTOCOL,
+	.features	= IPSET_TYPE_NAME | IPSET_DUMP_LAST,
+	.dimension	= IPSET_DIM_ONE,
+	.family		= AF_UNSPEC,
+	.revision	= 0,
+	.create		= list_set_create,
+	.create_policy	= {
+		[IPSET_ATTR_SIZE]	= { .type = NLA_U32 },
+		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
+	},
+	.adt_policy	= {
+		[IPSET_ATTR_NAME]	= { .type = NLA_STRING,
+					    .len = IPSET_MAXNAMELEN },
+		[IPSET_ATTR_NAMEREF]	= { .type = NLA_STRING,
+					    .len = IPSET_MAXNAMELEN },
+		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
+		[IPSET_ATTR_LINENO]	= { .type = NLA_U32 },
+		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
+	},
+	.me		= THIS_MODULE,
+};
+
+static int __init
+list_set_init(void)
+{
+	return ip_set_type_register(&list_set_type);
+}
+
+static void __exit
+list_set_fini(void)
+{
+	ip_set_type_unregister(&list_set_type);
+}
+
+module_init(list_set_init);
+module_exit(list_set_fini);
-- 
1.7.0.4