netfilter: nf_tables: support for set flushing

This patch adds support for set flushing, that consists of walking over
the set elements if the NFTA_SET_ELEM_LIST_ELEMENTS attribute is set.
This patch requires the following changes:

1) Add set->ops->deactivate_one() operation: This allows us to
   deactivate an element from the set element walk path, given we can
   skip the lookup that happens in ->deactivate().

2) Add a new nft_trans_alloc_gfp() function since we need to allocate
   transactions using GFP_ATOMIC given the set walk path happens with
   held rcu_read_lock.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2016-12-05 23:35:50 +01:00
parent 37df5301a3
commit 8411b6442e
4 changed files with 56 additions and 7 deletions

View File

@ -259,7 +259,8 @@ struct nft_expr;
* @lookup: look up an element within the set
* @insert: insert new element into set
* @activate: activate new element in the next generation
* @deactivate: deactivate element in the next generation
* @deactivate: lookup for element and deactivate it in the next generation
* @deactivate_one: deactivate element in the next generation
* @remove: remove element from set
* @walk: iterate over all set elemeennts
* @privsize: function to return size of set private data
@ -294,6 +295,9 @@ struct nft_set_ops {
void * (*deactivate)(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem);
bool (*deactivate_one)(const struct net *net,
const struct nft_set *set,
void *priv);
void (*remove)(const struct nft_set *set,
const struct nft_set_elem *elem);
void (*walk)(const struct nft_ctx *ctx,

View File

@ -111,12 +111,12 @@ static void nft_ctx_init(struct nft_ctx *ctx,
ctx->seq = nlh->nlmsg_seq;
}
static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
int msg_type, u32 size)
static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
int msg_type, u32 size, gfp_t gfp)
{
struct nft_trans *trans;
trans = kzalloc(sizeof(struct nft_trans) + size, GFP_KERNEL);
trans = kzalloc(sizeof(struct nft_trans) + size, gfp);
if (trans == NULL)
return NULL;
@ -126,6 +126,12 @@ static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
return trans;
}
static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
int msg_type, u32 size)
{
return nft_trans_alloc_gfp(ctx, msg_type, size, GFP_KERNEL);
}
static void nft_trans_destroy(struct nft_trans *trans)
{
list_del(&trans->list);
@ -3876,6 +3882,34 @@ err1:
return err;
}
static int nft_flush_set(const struct nft_ctx *ctx,
const struct nft_set *set,
const struct nft_set_iter *iter,
const struct nft_set_elem *elem)
{
struct nft_trans *trans;
int err;
trans = nft_trans_alloc_gfp(ctx, NFT_MSG_DELSETELEM,
sizeof(struct nft_trans_elem), GFP_ATOMIC);
if (!trans)
return -ENOMEM;
if (!set->ops->deactivate_one(ctx->net, set, elem->priv)) {
err = -ENOENT;
goto err1;
}
nft_trans_elem_set(trans) = (struct nft_set *)set;
nft_trans_elem(trans) = *((struct nft_set_elem *)elem);
list_add_tail(&trans->list, &ctx->net->nft.commit_list);
return 0;
err1:
kfree(trans);
return err;
}
static int nf_tables_delsetelem(struct net *net, struct sock *nlsk,
struct sk_buff *skb, const struct nlmsghdr *nlh,
const struct nlattr * const nla[])
@ -3886,9 +3920,6 @@ static int nf_tables_delsetelem(struct net *net, struct sock *nlsk,
struct nft_ctx ctx;
int rem, err = 0;
if (nla[NFTA_SET_ELEM_LIST_ELEMENTS] == NULL)
return -EINVAL;
err = nft_ctx_init_from_elemattr(&ctx, net, skb, nlh, nla, genmask);
if (err < 0)
return err;
@ -3900,6 +3931,18 @@ static int nf_tables_delsetelem(struct net *net, struct sock *nlsk,
if (!list_empty(&set->bindings) && set->flags & NFT_SET_CONSTANT)
return -EBUSY;
if (nla[NFTA_SET_ELEM_LIST_ELEMENTS] == NULL) {
struct nft_set_dump_args args = {
.iter = {
.genmask = genmask,
.fn = nft_flush_set,
},
};
set->ops->walk(&ctx, set, &args.iter);
return args.iter.err;
}
nla_for_each_nested(attr, nla[NFTA_SET_ELEM_LIST_ELEMENTS], rem) {
err = nft_del_setelem(&ctx, set, attr);
if (err < 0)

View File

@ -397,6 +397,7 @@ static struct nft_set_ops nft_hash_ops __read_mostly = {
.insert = nft_hash_insert,
.activate = nft_hash_activate,
.deactivate = nft_hash_deactivate,
.deactivate_one = nft_hash_deactivate_one,
.remove = nft_hash_remove,
.lookup = nft_hash_lookup,
.update = nft_hash_update,

View File

@ -304,6 +304,7 @@ static struct nft_set_ops nft_rbtree_ops __read_mostly = {
.insert = nft_rbtree_insert,
.remove = nft_rbtree_remove,
.deactivate = nft_rbtree_deactivate,
.deactivate_one = nft_rbtree_deactivate_one,
.activate = nft_rbtree_activate,
.lookup = nft_rbtree_lookup,
.walk = nft_rbtree_walk,