This patch allows you to refer to stateful objects from set elements.
This provides the infrastructure to create maps where the right hand
side of the mapping is a stateful object.

This allows us to build dictionaries of stateful objects, that you can
use to perform fast lookups using any arbitrary key combination.

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 include/net/netfilter/nf_tables.h        |  9 ++++
 include/uapi/linux/netfilter/nf_tables.h |  8 ++++
 net/netfilter/nf_tables_api.c            | 72 +++++++++++++++++++++++++++-----
 3 files changed, 79 insertions(+), 10 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h 
b/include/net/netfilter/nf_tables.h
index ce6fb6e83b32..85f0f03f1e87 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -326,6 +326,7 @@ void nft_unregister_set(struct nft_set_ops *ops);
  *     @name: name of the set
  *     @ktype: key type (numeric type defined by userspace, not used in the 
kernel)
  *     @dtype: data type (verdict or numeric type defined by userspace)
+ *     @objtype: object type (see NFT_OBJECT_* definitions)
  *     @size: maximum set size
  *     @nelems: number of elements
  *     @ndeact: number of deactivated elements queued for removal
@@ -347,6 +348,7 @@ struct nft_set {
        char                            name[NFT_SET_MAXNAMELEN];
        u32                             ktype;
        u32                             dtype;
+       u32                             objtype;
        u32                             size;
        atomic_t                        nelems;
        u32                             ndeact;
@@ -416,6 +418,7 @@ void nf_tables_unbind_set(const struct nft_ctx *ctx, struct 
nft_set *set,
  *     @NFT_SET_EXT_EXPIRATION: element expiration time
  *     @NFT_SET_EXT_USERDATA: user data associated with the element
  *     @NFT_SET_EXT_EXPR: expression assiociated with the element
+ *     @NFT_SET_EXT_OBJREF: stateful object reference associated with element
  *     @NFT_SET_EXT_NUM: number of extension types
  */
 enum nft_set_extensions {
@@ -426,6 +429,7 @@ enum nft_set_extensions {
        NFT_SET_EXT_EXPIRATION,
        NFT_SET_EXT_USERDATA,
        NFT_SET_EXT_EXPR,
+       NFT_SET_EXT_OBJREF,
        NFT_SET_EXT_NUM
 };
 
@@ -554,6 +558,11 @@ static inline struct nft_set_ext *nft_set_elem_ext(const 
struct nft_set *set,
        return elem + set->ops->elemsize;
 }
 
+static inline struct nft_object **nft_set_ext_obj(const struct nft_set_ext 
*ext)
+{
+       return nft_set_ext(ext, NFT_SET_EXT_OBJREF);
+}
+
 void *nft_set_elem_init(const struct nft_set *set,
                        const struct nft_set_ext_tmpl *tmpl,
                        const u32 *key, const u32 *data,
diff --git a/include/uapi/linux/netfilter/nf_tables.h 
b/include/uapi/linux/netfilter/nf_tables.h
index 4864caca1e8e..a6b52dbff08c 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -255,6 +255,7 @@ enum nft_rule_compat_attributes {
  * @NFT_SET_MAP: set is used as a dictionary
  * @NFT_SET_TIMEOUT: set uses timeouts
  * @NFT_SET_EVAL: set contains expressions for evaluation
+ * @NFT_SET_OBJECT: set contains stateful objects
  */
 enum nft_set_flags {
        NFT_SET_ANONYMOUS               = 0x1,
@@ -263,6 +264,7 @@ enum nft_set_flags {
        NFT_SET_MAP                     = 0x8,
        NFT_SET_TIMEOUT                 = 0x10,
        NFT_SET_EVAL                    = 0x20,
+       NFT_SET_OBJECT                  = 0x40,
 };
 
 /**
@@ -304,6 +306,7 @@ enum nft_set_desc_attributes {
  * @NFTA_SET_TIMEOUT: default timeout value (NLA_U64)
  * @NFTA_SET_GC_INTERVAL: garbage collection interval (NLA_U32)
  * @NFTA_SET_USERDATA: user data (NLA_BINARY)
+ * @NFTA_SET_OBJ_TYPE: stateful object type (NLA_U32: NFT_OBJECT_*)
  */
 enum nft_set_attributes {
        NFTA_SET_UNSPEC,
@@ -321,6 +324,7 @@ enum nft_set_attributes {
        NFTA_SET_GC_INTERVAL,
        NFTA_SET_USERDATA,
        NFTA_SET_PAD,
+       NFTA_SET_OBJ_TYPE,
        __NFTA_SET_MAX
 };
 #define NFTA_SET_MAX           (__NFTA_SET_MAX - 1)
@@ -344,6 +348,7 @@ enum nft_set_elem_flags {
  * @NFTA_SET_ELEM_EXPIRATION: expiration time (NLA_U64)
  * @NFTA_SET_ELEM_USERDATA: user data (NLA_BINARY)
  * @NFTA_SET_ELEM_EXPR: expression (NLA_NESTED: nft_expr_attributes)
+ * @NFTA_SET_ELEM_OBJREF: stateful object reference (NLA_STRING)
  */
 enum nft_set_elem_attributes {
        NFTA_SET_ELEM_UNSPEC,
@@ -355,6 +360,7 @@ enum nft_set_elem_attributes {
        NFTA_SET_ELEM_USERDATA,
        NFTA_SET_ELEM_EXPR,
        NFTA_SET_ELEM_PAD,
+       NFTA_SET_ELEM_OBJREF,
        __NFTA_SET_ELEM_MAX
 };
 #define NFTA_SET_ELEM_MAX      (__NFTA_SET_ELEM_MAX - 1)
@@ -1207,6 +1213,8 @@ enum nft_fib_flags {
 #define NFT_OBJECT_UNSPEC      0
 #define NFT_OBJECT_COUNTER     1
 #define NFT_OBJECT_QUOTA       2
+#define __NFT_OBJECT_MAX       3
+#define NFT_OBJECT_MAX         (__NFT_OBJECT_MAX - 1)
 
 /**
  * enum nft_object_attributes - nf_tables stateful object netlink attributes
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index c5419701ca79..8228714c42d5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2452,6 +2452,7 @@ static const struct nla_policy 
nft_set_policy[NFTA_SET_MAX + 1] = {
        [NFTA_SET_GC_INTERVAL]          = { .type = NLA_U32 },
        [NFTA_SET_USERDATA]             = { .type = NLA_BINARY,
                                            .len  = NFT_USERDATA_MAXLEN },
+       [NFTA_SET_OBJ_TYPE]             = { .type = NLA_U32 },
 };
 
 static const struct nla_policy nft_set_desc_policy[NFTA_SET_DESC_MAX + 1] = {
@@ -2609,6 +2610,9 @@ static int nf_tables_fill_set(struct sk_buff *skb, const 
struct nft_ctx *ctx,
                if (nla_put_be32(skb, NFTA_SET_DATA_LEN, htonl(set->dlen)))
                        goto nla_put_failure;
        }
+       if (set->flags & NFT_SET_OBJECT &&
+           nla_put_be32(skb, NFTA_SET_OBJ_TYPE, htonl(set->objtype)))
+               goto nla_put_failure;
 
        if (set->timeout &&
            nla_put_be64(skb, NFTA_SET_TIMEOUT,
@@ -2838,7 +2842,7 @@ static int nf_tables_newset(struct net *net, struct sock 
*nlsk,
        unsigned int size;
        bool create;
        u64 timeout;
-       u32 ktype, dtype, flags, policy, gc_int;
+       u32 ktype, dtype, flags, policy, gc_int, objtype;
        struct nft_set_desc desc;
        unsigned char *udata;
        u16 udlen;
@@ -2868,11 +2872,12 @@ static int nf_tables_newset(struct net *net, struct 
sock *nlsk,
                flags = ntohl(nla_get_be32(nla[NFTA_SET_FLAGS]));
                if (flags & ~(NFT_SET_ANONYMOUS | NFT_SET_CONSTANT |
                              NFT_SET_INTERVAL | NFT_SET_TIMEOUT |
-                             NFT_SET_MAP | NFT_SET_EVAL))
+                             NFT_SET_MAP | NFT_SET_EVAL |
+                             NFT_SET_OBJECT))
                        return -EINVAL;
-               /* Only one of both operations is supported */
-               if ((flags & (NFT_SET_MAP | NFT_SET_EVAL)) ==
-                            (NFT_SET_MAP | NFT_SET_EVAL))
+               /* Only one of these operations is supported */
+               if ((flags & (NFT_SET_MAP | NFT_SET_EVAL | NFT_SET_OBJECT)) ==
+                            (NFT_SET_MAP | NFT_SET_EVAL | NFT_SET_OBJECT))
                        return -EOPNOTSUPP;
        }
 
@@ -2897,6 +2902,19 @@ static int nf_tables_newset(struct net *net, struct sock 
*nlsk,
        } else if (flags & NFT_SET_MAP)
                return -EINVAL;
 
+       if (nla[NFTA_SET_OBJ_TYPE] != NULL) {
+               if (!(flags & NFT_SET_OBJECT))
+                       return -EINVAL;
+
+               objtype = ntohl(nla_get_be32(nla[NFTA_SET_OBJ_TYPE]));
+               if (objtype == NFT_OBJECT_UNSPEC ||
+                   objtype > NFT_OBJECT_MAX)
+                       return -EINVAL;
+       } else if (flags & NFT_SET_OBJECT)
+               return -EINVAL;
+       else
+               objtype = NFT_OBJECT_UNSPEC;
+
        timeout = 0;
        if (nla[NFTA_SET_TIMEOUT] != NULL) {
                if (!(flags & NFT_SET_TIMEOUT))
@@ -2984,6 +3002,7 @@ static int nf_tables_newset(struct net *net, struct sock 
*nlsk,
        set->ktype = ktype;
        set->klen  = desc.klen;
        set->dtype = dtype;
+       set->objtype = objtype;
        set->dlen  = desc.dlen;
        set->flags = flags;
        set->size  = desc.size;
@@ -3126,6 +3145,10 @@ const struct nft_set_ext_type nft_set_ext_types[] = {
        [NFT_SET_EXT_EXPR]              = {
                .align  = __alignof__(struct nft_expr),
        },
+       [NFT_SET_EXT_OBJREF]            = {
+               .len    = sizeof(struct nft_object *),
+               .align  = __alignof__(struct nft_object *),
+       },
        [NFT_SET_EXT_FLAGS]             = {
                .len    = sizeof(u8),
                .align  = __alignof__(u8),
@@ -3214,6 +3237,11 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
            nft_expr_dump(skb, NFTA_SET_ELEM_EXPR, nft_set_ext_expr(ext)) < 0)
                goto nla_put_failure;
 
+       if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF) &&
+           nla_put_string(skb, NFTA_SET_ELEM_OBJREF,
+                          (*nft_set_ext_obj(ext))->name) < 0)
+               goto nla_put_failure;
+
        if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
            nla_put_be32(skb, NFTA_SET_ELEM_FLAGS,
                         htonl(*nft_set_ext_flags(ext))))
@@ -3508,7 +3536,8 @@ void nft_set_elem_destroy(const struct nft_set *set, void 
*elem,
                nft_data_uninit(nft_set_ext_data(ext), set->dtype);
        if (destroy_expr && nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
                nf_tables_expr_destroy(NULL, nft_set_ext_expr(ext));
-
+       if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF))
+               (*nft_set_ext_obj(ext))->use--;
        kfree(elem);
 }
 EXPORT_SYMBOL_GPL(nft_set_elem_destroy);
@@ -3533,11 +3562,13 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct 
nft_set *set,
                            const struct nlattr *attr, u32 nlmsg_flags)
 {
        struct nlattr *nla[NFTA_SET_ELEM_MAX + 1];
+       u8 genmask = nft_genmask_next(ctx->net);
        struct nft_data_desc d1, d2;
        struct nft_set_ext_tmpl tmpl;
        struct nft_set_ext *ext, *ext2;
        struct nft_set_elem elem;
        struct nft_set_binding *binding;
+       struct nft_object *obj = NULL;
        struct nft_userdata *udata;
        struct nft_data data;
        enum nft_registers dreg;
@@ -3600,6 +3631,20 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct 
nft_set *set,
                        nft_set_ext_add(&tmpl, NFT_SET_EXT_TIMEOUT);
        }
 
+       if (nla[NFTA_SET_ELEM_OBJREF] != NULL) {
+               if (!(set->flags & NFT_SET_OBJECT)) {
+                       err = -EINVAL;
+                       goto err2;
+               }
+               obj = nf_tables_obj_lookup(ctx->table, 
nla[NFTA_SET_ELEM_OBJREF],
+                                          set->objtype, genmask);
+               if (IS_ERR(obj)) {
+                       err = PTR_ERR(obj);
+                       goto err2;
+               }
+               nft_set_ext_add(&tmpl, NFT_SET_EXT_OBJREF);
+       }
+
        if (nla[NFTA_SET_ELEM_DATA] != NULL) {
                err = nft_data_init(ctx, &data, sizeof(data), &d2,
                                    nla[NFTA_SET_ELEM_DATA]);
@@ -3658,6 +3703,10 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct 
nft_set *set,
                udata->len = ulen - 1;
                nla_memcpy(&udata->data, nla[NFTA_SET_ELEM_USERDATA], ulen);
        }
+       if (obj) {
+               *nft_set_ext_obj(ext) = obj;
+               obj->use++;
+       }
 
        trans = nft_trans_elem_alloc(ctx, NFT_MSG_NEWSETELEM, set);
        if (trans == NULL)
@@ -3667,10 +3716,13 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct 
nft_set *set,
        err = set->ops->insert(ctx->net, set, &elem, &ext2);
        if (err) {
                if (err == -EEXIST) {
-                       if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA) &&
-                           nft_set_ext_exists(ext2, NFT_SET_EXT_DATA) &&
-                           memcmp(nft_set_ext_data(ext),
-                                  nft_set_ext_data(ext2), set->dlen) != 0)
+                       if ((nft_set_ext_exists(ext, NFT_SET_EXT_DATA) &&
+                            nft_set_ext_exists(ext2, NFT_SET_EXT_DATA) &&
+                            memcmp(nft_set_ext_data(ext),
+                                   nft_set_ext_data(ext2), set->dlen) != 0) ||
+                           (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF) &&
+                            nft_set_ext_exists(ext2, NFT_SET_EXT_OBJREF) &&
+                            *nft_set_ext_obj(ext) != *nft_set_ext_obj(ext2)))
                                err = -EBUSY;
                        else if (!(nlmsg_flags & NLM_F_EXCL))
                                err = 0;
-- 
2.1.4

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