net/netfilter/nft_objref.c

   1 /*
   2  * Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables.h>
  16
  17 #define nft_objref_priv(expr)   *((struct nft_object **)nft_expr_priv(expr))
  18
  19 static void nft_objref_eval(const struct nft_expr *expr,
  20                             struct nft_regs *regs,
  21                             const struct nft_pktinfo *pkt)
  22 {
  23         struct nft_object *obj = nft_objref_priv(expr);
  24
  25         obj->ops->eval(obj, regs, pkt);
  26 }
  27
  28 static int nft_objref_init(const struct nft_ctx *ctx,
  29                            const struct nft_expr *expr,
  30                            const struct nlattr * const tb[])
  31 {
  32         struct nft_object *obj = nft_objref_priv(expr);
  33         u8 genmask = nft_genmask_next(ctx->net);
  34         u32 objtype;
  35
  36         if (!tb[NFTA_OBJREF_IMM_NAME] ||
  37             !tb[NFTA_OBJREF_IMM_TYPE])
  38                 return -EINVAL;
  39
  40         objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
  41         obj = nft_obj_lookup(ctx->table, tb[NFTA_OBJREF_IMM_NAME], objtype,
  42                              genmask);
  43         if (IS_ERR(obj))
  44                 return -ENOENT;
  45
  46         nft_objref_priv(expr) = obj;
  47         obj->use++;
  48
  49         return 0;
  50 }
  51
  52 static int nft_objref_dump(struct sk_buff *skb, const struct nft_expr *expr)
  53 {
  54         const struct nft_object *obj = nft_objref_priv(expr);
  55
  56         if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->name) ||
  57             nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE,
  58                          htonl(obj->ops->type->type)))
  59                 goto nla_put_failure;
  60
  61         return 0;
  62
  63 nla_put_failure:
  64         return -1;
  65 }
  66
  67 static void nft_objref_deactivate(const struct nft_ctx *ctx,
  68                                   const struct nft_expr *expr,
  69                                   enum nft_trans_phase phase)
  70 {
  71         struct nft_object *obj = nft_objref_priv(expr);
  72
  73         if (phase == NFT_TRANS_COMMIT)
  74                 return;
  75
  76         obj->use--;
  77 }
  78
  79 static void nft_objref_activate(const struct nft_ctx *ctx,
  80                                 const struct nft_expr *expr)
  81 {
  82         struct nft_object *obj = nft_objref_priv(expr);
  83
  84         obj->use++;
  85 }
  86
  87 static struct nft_expr_type nft_objref_type;
  88 static const struct nft_expr_ops nft_objref_ops = {
  89         .type           = &nft_objref_type,
  90         .size           = NFT_EXPR_SIZE(sizeof(struct nft_object *)),
  91         .eval           = nft_objref_eval,
  92         .init           = nft_objref_init,
  93         .activate       = nft_objref_activate,
  94         .deactivate     = nft_objref_deactivate,
  95         .dump           = nft_objref_dump,
  96 };
  97
  98 struct nft_objref_map {
  99         struct nft_set          *set;
 100         enum nft_registers      sreg:8;
 101         struct nft_set_binding  binding;
 102 };
 103
 104 static void nft_objref_map_eval(const struct nft_expr *expr,
 105                                 struct nft_regs *regs,
 106                                 const struct nft_pktinfo *pkt)
 107 {
 108         struct nft_objref_map *priv = nft_expr_priv(expr);
 109         const struct nft_set *set = priv->set;
 110         const struct nft_set_ext *ext;
 111         struct nft_object *obj;
 112         bool found;
 113
 114         found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
 115                                  &ext);
 116         if (!found) {
 117                 regs->verdict.code = NFT_BREAK;
 118                 return;
 119         }
 120         obj = *nft_set_ext_obj(ext);
 121         obj->ops->eval(obj, regs, pkt);
 122 }
 123
 124 static int nft_objref_map_init(const struct nft_ctx *ctx,
 125                                const struct nft_expr *expr,
 126                                const struct nlattr * const tb[])
 127 {
 128         struct nft_objref_map *priv = nft_expr_priv(expr);
 129         u8 genmask = nft_genmask_next(ctx->net);
 130         struct nft_set *set;
 131         int err;
 132
 133         set = nft_set_lookup_global(ctx->net, ctx->table,
 134                                     tb[NFTA_OBJREF_SET_NAME],
 135                                     tb[NFTA_OBJREF_SET_ID], genmask);
 136         if (IS_ERR(set))
 137                 return PTR_ERR(set);
 138
 139         if (!(set->flags & NFT_SET_OBJECT))
 140                 return -EINVAL;
 141
 142         priv->sreg = nft_parse_register(tb[NFTA_OBJREF_SET_SREG]);
 143         err = nft_validate_register_load(priv->sreg, set->klen);
 144         if (err < 0)
 145                 return err;
 146
 147         priv->binding.flags = set->flags & NFT_SET_OBJECT;
 148
 149         err = nf_tables_bind_set(ctx, set, &priv->binding);
 150         if (err < 0)
 151                 return err;
 152
 153         priv->set = set;
 154         return 0;
 155 }
 156
 157 static int nft_objref_map_dump(struct sk_buff *skb, const struct nft_expr *expr)
 158 {
 159         const struct nft_objref_map *priv = nft_expr_priv(expr);
 160
 161         if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) ||
 162             nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name))
 163                 goto nla_put_failure;
 164
 165         return 0;
 166
 167 nla_put_failure:
 168         return -1;
 169 }
 170
 171 static void nft_objref_map_deactivate(const struct nft_ctx *ctx,
 172                                       const struct nft_expr *expr,
 173                                       enum nft_trans_phase phase)
 174 {
 175         struct nft_objref_map *priv = nft_expr_priv(expr);
 176
 177         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 178 }
 179
 180 static void nft_objref_map_activate(const struct nft_ctx *ctx,
 181                                     const struct nft_expr *expr)
 182 {
 183         struct nft_objref_map *priv = nft_expr_priv(expr);
 184
 185         priv->set->use++;
 186 }
 187
 188 static void nft_objref_map_destroy(const struct nft_ctx *ctx,
 189                                    const struct nft_expr *expr)
 190 {
 191         struct nft_objref_map *priv = nft_expr_priv(expr);
 192
 193         nf_tables_destroy_set(ctx, priv->set);
 194 }
 195
 196 static struct nft_expr_type nft_objref_type;
 197 static const struct nft_expr_ops nft_objref_map_ops = {
 198         .type           = &nft_objref_type,
 199         .size           = NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
 200         .eval           = nft_objref_map_eval,
 201         .init           = nft_objref_map_init,
 202         .activate       = nft_objref_map_activate,
 203         .deactivate     = nft_objref_map_deactivate,
 204         .destroy        = nft_objref_map_destroy,
 205         .dump           = nft_objref_map_dump,
 206 };
 207
 208 static const struct nft_expr_ops *
 209 nft_objref_select_ops(const struct nft_ctx *ctx,
 210                       const struct nlattr * const tb[])
 211 {
 212         if (tb[NFTA_OBJREF_SET_SREG] &&
 213             (tb[NFTA_OBJREF_SET_NAME] ||
 214              tb[NFTA_OBJREF_SET_ID]))
 215                 return &nft_objref_map_ops;
 216         else if (tb[NFTA_OBJREF_IMM_NAME] &&
 217                  tb[NFTA_OBJREF_IMM_TYPE])
 218                 return &nft_objref_ops;
 219
 220         return ERR_PTR(-EOPNOTSUPP);
 221 }
 222
 223 static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
 224         [NFTA_OBJREF_IMM_NAME]  = { .type = NLA_STRING,
 225                                     .len = NFT_OBJ_MAXNAMELEN - 1 },
 226         [NFTA_OBJREF_IMM_TYPE]  = { .type = NLA_U32 },
 227         [NFTA_OBJREF_SET_SREG]  = { .type = NLA_U32 },
 228         [NFTA_OBJREF_SET_NAME]  = { .type = NLA_STRING,
 229                                     .len = NFT_SET_MAXNAMELEN - 1 },
 230         [NFTA_OBJREF_SET_ID]    = { .type = NLA_U32 },
 231 };
 232
 233 static struct nft_expr_type nft_objref_type __read_mostly = {
 234         .name           = "objref",
 235         .select_ops     = nft_objref_select_ops,
 236         .policy         = nft_objref_policy,
 237         .maxattr        = NFTA_OBJREF_MAX,
 238         .owner          = THIS_MODULE,
 239 };
 240
 241 static int __init nft_objref_module_init(void)
 242 {
 243         return nft_register_expr(&nft_objref_type);
 244 }
 245
 246 static void __exit nft_objref_module_exit(void)
 247 {
 248         nft_unregister_expr(&nft_objref_type);
 249 }
 250
 251 module_init(nft_objref_module_init);
 252 module_exit(nft_objref_module_exit);
 253
 254 MODULE_LICENSE("GPL");
 255 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 256 MODULE_ALIAS_NFT_EXPR("objref");