net/netfilter/nft_immediate.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   4  *
   5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/netlink.h>
  12 #include <linux/netfilter.h>
  13 #include <linux/netfilter/nf_tables.h>
  14 #include <net/netfilter/nf_tables_core.h>
  15 #include <net/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables_offload.h>
  17
  18 void nft_immediate_eval(const struct nft_expr *expr,
  19                         struct nft_regs *regs,
  20                         const struct nft_pktinfo *pkt)
  21 {
  22         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  23
  24         nft_data_copy(&regs->data[priv->dreg], &priv->data, priv->dlen);
  25 }
  26
  27 static const struct nla_policy nft_immediate_policy[NFTA_IMMEDIATE_MAX + 1] = {
  28         [NFTA_IMMEDIATE_DREG]   = { .type = NLA_U32 },
  29         [NFTA_IMMEDIATE_DATA]   = { .type = NLA_NESTED },
  30 };
  31
  32 static enum nft_data_types nft_reg_to_type(const struct nlattr *nla)
  33 {
  34         enum nft_data_types type;
  35         u8 reg;
  36
  37         reg = ntohl(nla_get_be32(nla));
  38         if (reg == NFT_REG_VERDICT)
  39                 type = NFT_DATA_VERDICT;
  40         else
  41                 type = NFT_DATA_VALUE;
  42
  43         return type;
  44 }
  45
  46 static int nft_immediate_init(const struct nft_ctx *ctx,
  47                               const struct nft_expr *expr,
  48                               const struct nlattr * const tb[])
  49 {
  50         struct nft_immediate_expr *priv = nft_expr_priv(expr);
  51         struct nft_data_desc desc = {
  52                 .size   = sizeof(priv->data),
  53         };
  54         int err;
  55
  56         if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
  57             tb[NFTA_IMMEDIATE_DATA] == NULL)
  58                 return -EINVAL;
  59
  60         desc.type = nft_reg_to_type(tb[NFTA_IMMEDIATE_DREG]);
  61         err = nft_data_init(ctx, &priv->data, &desc, tb[NFTA_IMMEDIATE_DATA]);
  62         if (err < 0)
  63                 return err;
  64
  65         priv->dlen = desc.len;
  66
  67         err = nft_parse_register_store(ctx, tb[NFTA_IMMEDIATE_DREG],
  68                                        &priv->dreg, &priv->data, desc.type,
  69                                        desc.len);
  70         if (err < 0)
  71                 goto err1;
  72
  73         if (priv->dreg == NFT_REG_VERDICT) {
  74                 struct nft_chain *chain = priv->data.verdict.chain;
  75
  76                 switch (priv->data.verdict.code) {
  77                 case NFT_JUMP:
  78                 case NFT_GOTO:
  79                         err = nf_tables_bind_chain(ctx, chain);
  80                         if (err < 0)
  81                                 return err;
  82                         break;
  83                 default:
  84                         break;
  85                 }
  86         }
  87
  88         return 0;
  89
  90 err1:
  91         nft_data_release(&priv->data, desc.type);
  92         return err;
  93 }
  94
  95 static void nft_immediate_activate(const struct nft_ctx *ctx,
  96                                    const struct nft_expr *expr)
  97 {
  98         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  99         const struct nft_data *data = &priv->data;
 100         struct nft_ctx chain_ctx;
 101         struct nft_chain *chain;
 102         struct nft_rule *rule;
 103
 104         if (priv->dreg == NFT_REG_VERDICT) {
 105                 switch (data->verdict.code) {
 106                 case NFT_JUMP:
 107                 case NFT_GOTO:
 108                         chain = data->verdict.chain;
 109                         if (!nft_chain_binding(chain))
 110                                 break;
 111
 112                         chain_ctx = *ctx;
 113                         chain_ctx.chain = chain;
 114
 115                         list_for_each_entry(rule, &chain->rules, list)
 116                                 nft_rule_expr_activate(&chain_ctx, rule);
 117
 118                         nft_clear(ctx->net, chain);
 119                         break;
 120                 default:
 121                         break;
 122                 }
 123         }
 124
 125         return nft_data_hold(&priv->data, nft_dreg_to_type(priv->dreg));
 126 }
 127
 128 static void nft_immediate_deactivate(const struct nft_ctx *ctx,
 129                                      const struct nft_expr *expr,
 130                                      enum nft_trans_phase phase)
 131 {
 132         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 133         const struct nft_data *data = &priv->data;
 134         struct nft_ctx chain_ctx;
 135         struct nft_chain *chain;
 136         struct nft_rule *rule;
 137
 138         if (priv->dreg == NFT_REG_VERDICT) {
 139                 switch (data->verdict.code) {
 140                 case NFT_JUMP:
 141                 case NFT_GOTO:
 142                         chain = data->verdict.chain;
 143                         if (!nft_chain_binding(chain))
 144                                 break;
 145
 146                         chain_ctx = *ctx;
 147                         chain_ctx.chain = chain;
 148
 149                         list_for_each_entry(rule, &chain->rules, list)
 150                                 nft_rule_expr_deactivate(&chain_ctx, rule, phase);
 151
 152                         switch (phase) {
 153                         case NFT_TRANS_PREPARE_ERROR:
 154                                 nf_tables_unbind_chain(ctx, chain);
 155                                 fallthrough;
 156                         case NFT_TRANS_PREPARE:
 157                                 nft_deactivate_next(ctx->net, chain);
 158                                 break;
 159                         default:
 160                                 nft_chain_del(chain);
 161                                 chain->bound = false;
 162                                 chain->table->use--;
 163                                 break;
 164                         }
 165                         break;
 166                 default:
 167                         break;
 168                 }
 169         }
 170
 171         if (phase == NFT_TRANS_COMMIT)
 172                 return;
 173
 174         return nft_data_release(&priv->data, nft_dreg_to_type(priv->dreg));
 175 }
 176
 177 static void nft_immediate_destroy(const struct nft_ctx *ctx,
 178                                   const struct nft_expr *expr)
 179 {
 180         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 181         const struct nft_data *data = &priv->data;
 182         struct nft_rule *rule, *n;
 183         struct nft_ctx chain_ctx;
 184         struct nft_chain *chain;
 185
 186         if (priv->dreg != NFT_REG_VERDICT)
 187                 return;
 188
 189         switch (data->verdict.code) {
 190         case NFT_JUMP:
 191         case NFT_GOTO:
 192                 chain = data->verdict.chain;
 193
 194                 if (!nft_chain_binding(chain))
 195                         break;
 196
 197                 /* Rule construction failed, but chain is already bound:
 198                  * let the transaction records release this chain and its rules.
 199                  */
 200                 if (chain->bound) {
 201                         chain->use--;
 202                         break;
 203                 }
 204
 205                 /* Rule has been deleted, release chain and its rules. */
 206                 chain_ctx = *ctx;
 207                 chain_ctx.chain = chain;
 208
 209                 chain->use--;
 210                 list_for_each_entry_safe(rule, n, &chain->rules, list) {
 211                         chain->use--;
 212                         list_del(&rule->list);
 213                         nf_tables_rule_destroy(&chain_ctx, rule);
 214                 }
 215                 nf_tables_chain_destroy(&chain_ctx);
 216                 break;
 217         default:
 218                 break;
 219         }
 220 }
 221
 222 static int nft_immediate_dump(struct sk_buff *skb,
 223                               const struct nft_expr *expr, bool reset)
 224 {
 225         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 226
 227         if (nft_dump_register(skb, NFTA_IMMEDIATE_DREG, priv->dreg))
 228                 goto nla_put_failure;
 229
 230         return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
 231                              nft_dreg_to_type(priv->dreg), priv->dlen);
 232
 233 nla_put_failure:
 234         return -1;
 235 }
 236
 237 static int nft_immediate_validate(const struct nft_ctx *ctx,
 238                                   const struct nft_expr *expr,
 239                                   const struct nft_data **d)
 240 {
 241         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 242         struct nft_ctx *pctx = (struct nft_ctx *)ctx;
 243         const struct nft_data *data;
 244         int err;
 245
 246         if (priv->dreg != NFT_REG_VERDICT)
 247                 return 0;
 248
 249         data = &priv->data;
 250
 251         switch (data->verdict.code) {
 252         case NFT_JUMP:
 253         case NFT_GOTO:
 254                 pctx->level++;
 255                 err = nft_chain_validate(ctx, data->verdict.chain);
 256                 if (err < 0)
 257                         return err;
 258                 pctx->level--;
 259                 break;
 260         default:
 261                 break;
 262         }
 263
 264         return 0;
 265 }
 266
 267 static int nft_immediate_offload_verdict(struct nft_offload_ctx *ctx,
 268                                          struct nft_flow_rule *flow,
 269                                          const struct nft_immediate_expr *priv)
 270 {
 271         struct flow_action_entry *entry;
 272         const struct nft_data *data;
 273
 274         entry = &flow->rule->action.entries[ctx->num_actions++];
 275
 276         data = &priv->data;
 277         switch (data->verdict.code) {
 278         case NF_ACCEPT:
 279                 entry->id = FLOW_ACTION_ACCEPT;
 280                 break;
 281         case NF_DROP:
 282                 entry->id = FLOW_ACTION_DROP;
 283                 break;
 284         default:
 285                 return -EOPNOTSUPP;
 286         }
 287
 288         return 0;
 289 }
 290
 291 static int nft_immediate_offload(struct nft_offload_ctx *ctx,
 292                                  struct nft_flow_rule *flow,
 293                                  const struct nft_expr *expr)
 294 {
 295         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 296
 297         if (priv->dreg == NFT_REG_VERDICT)
 298                 return nft_immediate_offload_verdict(ctx, flow, priv);
 299
 300         memcpy(&ctx->regs[priv->dreg].data, &priv->data, sizeof(priv->data));
 301
 302         return 0;
 303 }
 304
 305 static bool nft_immediate_offload_action(const struct nft_expr *expr)
 306 {
 307         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 308
 309         if (priv->dreg == NFT_REG_VERDICT)
 310                 return true;
 311
 312         return false;
 313 }
 314
 315 static bool nft_immediate_reduce(struct nft_regs_track *track,
 316                                  const struct nft_expr *expr)
 317 {
 318         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 319
 320         if (priv->dreg != NFT_REG_VERDICT)
 321                 nft_reg_track_cancel(track, priv->dreg, priv->dlen);
 322
 323         return false;
 324 }
 325
 326 static const struct nft_expr_ops nft_imm_ops = {
 327         .type           = &nft_imm_type,
 328         .size           = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
 329         .eval           = nft_immediate_eval,
 330         .init           = nft_immediate_init,
 331         .activate       = nft_immediate_activate,
 332         .deactivate     = nft_immediate_deactivate,
 333         .destroy        = nft_immediate_destroy,
 334         .dump           = nft_immediate_dump,
 335         .validate       = nft_immediate_validate,
 336         .reduce         = nft_immediate_reduce,
 337         .offload        = nft_immediate_offload,
 338         .offload_action = nft_immediate_offload_action,
 339 };
 340
 341 struct nft_expr_type nft_imm_type __read_mostly = {
 342         .name           = "immediate",
 343         .ops            = &nft_imm_ops,
 344         .policy         = nft_immediate_policy,
 345         .maxattr        = NFTA_IMMEDIATE_MAX,
 346         .owner          = THIS_MODULE,
 347 };