This patch implements the delete operation from the ruleset.

It implements a new delete() function in nft_set_rhash. It is simpler
to use than the already existing remove(), because it only takes the set
and the key as arguments, whereas remove() expects a full
nft_set_elem structure.

Signed-off-by: Ander Juaristi <a...@juaristi.eus>
---
 include/net/netfilter/nf_tables.h        | 17 ++++++---
 include/uapi/linux/netfilter/nf_tables.h |  1 +
 net/netfilter/nft_dynset.c               | 44 +++++++++++++++++-------
 net/netfilter/nft_set_hash.c             | 19 ++++++++++
 4 files changed, 63 insertions(+), 18 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h 
b/include/net/netfilter/nf_tables.h
index 9e8493aad49d..ddea26ba14b1 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -286,24 +286,25 @@ struct nft_expr;
 /**
  *     struct nft_set_ops - nf_tables set operations
  *
+ *     @update: update an element if exists, add it if doesn't exist
+ *     @delete: delete an element
  *     @lookup: look up an element within the set
  *     @insert: insert new element into set
  *     @activate: activate new element in the next generation
  *     @deactivate: lookup for element and deactivate it in the next generation
  *     @flush: deactivate element in the next generation
  *     @remove: remove element from set
- *     @walk: iterate over all set elemeennts
+ *     @walk: iterate over all set elements
  *     @get: get set elements
  *     @privsize: function to return size of set private data
  *     @init: initialize private data of new set instance
  *     @destroy: destroy private data of set instance
  *     @elemsize: element private size
+ *
+ *     Operations update and delete have simpler interfaces, and currently
+ *     only used in the packet path. All the rest are for the control plane.
  */
 struct nft_set_ops {
-       bool                            (*lookup)(const struct net *net,
-                                                 const struct nft_set *set,
-                                                 const u32 *key,
-                                                 const struct nft_set_ext 
**ext);
        bool                            (*update)(struct nft_set *set,
                                                  const u32 *key,
                                                  void *(*new)(struct nft_set *,
@@ -312,7 +313,13 @@ struct nft_set_ops {
                                                  const struct nft_expr *expr,
                                                  struct nft_regs *regs,
                                                  const struct nft_set_ext 
**ext);
+       bool                            (*delete)(const struct nft_set *set,
+                                                 const u32 *key);
 
+       bool                            (*lookup)(const struct net *net,
+                                                 const struct nft_set *set,
+                                                 const u32 *key,
+                                                 const struct nft_set_ext 
**ext);
        int                             (*insert)(const struct net *net,
                                                  const struct nft_set *set,
                                                  const struct nft_set_elem 
*elem,
diff --git a/include/uapi/linux/netfilter/nf_tables.h 
b/include/uapi/linux/netfilter/nf_tables.h
index c6c8ec5c7c00..e8483e1e7146 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -634,6 +634,7 @@ enum nft_lookup_attributes {
 enum nft_dynset_ops {
        NFT_DYNSET_OP_ADD,
        NFT_DYNSET_OP_UPDATE,
+       NFT_DYNSET_OP_DELETE,
 };
 
 enum nft_dynset_flags {
diff --git a/net/netfilter/nft_dynset.c b/net/netfilter/nft_dynset.c
index bfb9f7463b03..0cb775be1f2e 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -79,37 +79,54 @@ static void *nft_dynset_new(struct nft_set *set, const 
struct nft_expr *expr,
        return NULL;
 }
 
-void nft_dynset_eval(const struct nft_expr *expr,
-                    struct nft_regs *regs, const struct nft_pktinfo *pkt)
+static bool nft_dynset_update(u8 sreg_key, int op, u64 timeout,
+                             const struct nft_expr *expr,
+                             const struct nft_pktinfo *pkt,
+                             struct nft_regs *regs, struct nft_set *set)
 {
-       const struct nft_dynset *priv = nft_expr_priv(expr);
-       struct nft_set *set = priv->set;
        const struct nft_set_ext *ext;
        const struct nft_expr *sexpr;
-       u64 timeout;
 
-       if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
+       if (set->ops->update(set, &regs->data[sreg_key], nft_dynset_new,
                             expr, regs, &ext)) {
                sexpr = NULL;
                if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
                        sexpr = nft_set_ext_expr(ext);
 
-               if (priv->op == NFT_DYNSET_OP_UPDATE &&
+               if (op == NFT_DYNSET_OP_UPDATE &&
                    nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
-                       timeout = priv->timeout ? : set->timeout;
+                       timeout = timeout ? : set->timeout;
                        *nft_set_ext_expiration(ext) = get_jiffies_64() + 
timeout;
                }
 
                if (sexpr != NULL)
                        sexpr->ops->eval(sexpr, regs, pkt);
 
-               if (priv->invert)
-                       regs->verdict.code = NFT_BREAK;
-               return;
+               return true;
        }
 
-       if (!priv->invert)
-               regs->verdict.code = NFT_BREAK;
+       return false;
+}
+
+void nft_dynset_eval(const struct nft_expr *expr,
+                    struct nft_regs *regs, const struct nft_pktinfo *pkt)
+{
+       const struct nft_dynset *priv = nft_expr_priv(expr);
+       struct nft_set *set = priv->set;
+
+       if (priv->op == NFT_DYNSET_OP_DELETE) {
+               set->ops->delete(set, &regs->data[priv->sreg_key]);
+       } else {
+               if (nft_dynset_update(priv->sreg_key, priv->op, priv->timeout,
+                                     expr, pkt, regs, set)) {
+                       if (priv->invert)
+                               regs->verdict.code = NFT_BREAK;
+                       return;
+               }
+
+               if (!priv->invert)
+                       regs->verdict.code = NFT_BREAK;
+       }
 }
 
 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
@@ -165,6 +182,7 @@ static int nft_dynset_init(const struct nft_ctx *ctx,
        priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
        switch (priv->op) {
        case NFT_DYNSET_OP_ADD:
+       case NFT_DYNSET_OP_DELETE:
                break;
        case NFT_DYNSET_OP_UPDATE:
                if (!(set->flags & NFT_SET_TIMEOUT))
diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c
index 03df08801e28..867abcb488bc 100644
--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -237,6 +237,24 @@ static void nft_rhash_remove(const struct net *net,
        rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params);
 }
 
+static bool nft_rhash_delete(const struct nft_set *set,
+                            const u32 *key)
+{
+       struct nft_rhash *priv = nft_set_priv(set);
+       struct nft_rhash_elem *he;
+       struct nft_rhash_cmp_arg arg = {
+               .genmask = NFT_GENMASK_ANY,
+               .set = set,
+               .key = key,
+       };
+
+       he = rhashtable_lookup(&priv->ht, &arg, nft_rhash_params);
+       if (he == NULL)
+               return false;
+
+       return (rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params) 
== 0);
+}
+
 static void nft_rhash_walk(const struct nft_ctx *ctx, struct nft_set *set,
                           struct nft_set_iter *iter)
 {
@@ -665,6 +683,7 @@ struct nft_set_type nft_set_rhash_type __read_mostly = {
                .remove         = nft_rhash_remove,
                .lookup         = nft_rhash_lookup,
                .update         = nft_rhash_update,
+               .delete         = nft_rhash_delete,
                .walk           = nft_rhash_walk,
                .get            = nft_rhash_get,
        },
-- 
2.17.1

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