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                                 goto err1;
  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_chain_deactivate(const struct nft_ctx *ctx,
 129                                            struct nft_chain *chain,
 130                                            enum nft_trans_phase phase)
 131 {
 132         struct nft_ctx chain_ctx;
 133         struct nft_rule *rule;
 134
 135         chain_ctx = *ctx;
 136         chain_ctx.chain = chain;
 137
 138         list_for_each_entry(rule, &chain->rules, list)
 139                 nft_rule_expr_deactivate(&chain_ctx, rule, phase);
 140 }
 141
 142 static void nft_immediate_deactivate(const struct nft_ctx *ctx,
 143                                      const struct nft_expr *expr,
 144                                      enum nft_trans_phase phase)
 145 {
 146         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 147         const struct nft_data *data = &priv->data;
 148         struct nft_chain *chain;
 149
 150         if (priv->dreg == NFT_REG_VERDICT) {
 151                 switch (data->verdict.code) {
 152                 case NFT_JUMP:
 153                 case NFT_GOTO:
 154                         chain = data->verdict.chain;
 155                         if (!nft_chain_binding(chain))
 156                                 break;
 157
 158                         switch (phase) {
 159                         case NFT_TRANS_PREPARE_ERROR:
 160                                 nf_tables_unbind_chain(ctx, chain);
 161                                 nft_deactivate_next(ctx->net, chain);
 162                                 break;
 163                         case NFT_TRANS_PREPARE:
 164                                 nft_immediate_chain_deactivate(ctx, chain, phase);
 165                                 nft_deactivate_next(ctx->net, chain);
 166                                 break;
 167                         default:
 168                                 nft_immediate_chain_deactivate(ctx, chain, phase);
 169                                 nft_chain_del(chain);
 170                                 chain->bound = false;
 171                                 nft_use_dec(&chain->table->use);
 172                                 break;
 173                         }
 174                         break;
 175                 default:
 176                         break;
 177                 }
 178         }
 179
 180         if (phase == NFT_TRANS_COMMIT)
 181                 return;
 182
 183         return nft_data_release(&priv->data, nft_dreg_to_type(priv->dreg));
 184 }
 185
 186 static void nft_immediate_destroy(const struct nft_ctx *ctx,
 187                                   const struct nft_expr *expr)
 188 {
 189         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 190         const struct nft_data *data = &priv->data;
 191         struct nft_rule *rule, *n;
 192         struct nft_ctx chain_ctx;
 193         struct nft_chain *chain;
 194
 195         if (priv->dreg != NFT_REG_VERDICT)
 196                 return;
 197
 198         switch (data->verdict.code) {
 199         case NFT_JUMP:
 200         case NFT_GOTO:
 201                 chain = data->verdict.chain;
 202
 203                 if (!nft_chain_binding(chain))
 204                         break;
 205
 206                 /* Rule construction failed, but chain is already bound:
 207                  * let the transaction records release this chain and its rules.
 208                  */
 209                 if (chain->bound) {
 210                         nft_use_dec(&chain->use);
 211                         break;
 212                 }
 213
 214                 /* Rule has been deleted, release chain and its rules. */
 215                 chain_ctx = *ctx;
 216                 chain_ctx.chain = chain;
 217
 218                 nft_use_dec(&chain->use);
 219                 list_for_each_entry_safe(rule, n, &chain->rules, list) {
 220                         nft_use_dec(&chain->use);
 221                         list_del(&rule->list);
 222                         nf_tables_rule_destroy(&chain_ctx, rule);
 223                 }
 224                 nf_tables_chain_destroy(chain);
 225                 break;
 226         default:
 227                 break;
 228         }
 229 }
 230
 231 static int nft_immediate_dump(struct sk_buff *skb,
 232                               const struct nft_expr *expr, bool reset)
 233 {
 234         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 235
 236         if (nft_dump_register(skb, NFTA_IMMEDIATE_DREG, priv->dreg))
 237                 goto nla_put_failure;
 238
 239         return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
 240                              nft_dreg_to_type(priv->dreg), priv->dlen);
 241
 242 nla_put_failure:
 243         return -1;
 244 }
 245
 246 static int nft_immediate_validate(const struct nft_ctx *ctx,
 247                                   const struct nft_expr *expr)
 248 {
 249         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 250         struct nft_ctx *pctx = (struct nft_ctx *)ctx;
 251         const struct nft_data *data;
 252         int err;
 253
 254         if (priv->dreg != NFT_REG_VERDICT)
 255                 return 0;
 256
 257         data = &priv->data;
 258
 259         switch (data->verdict.code) {
 260         case NFT_JUMP:
 261         case NFT_GOTO:
 262                 pctx->level++;
 263                 err = nft_chain_validate(ctx, data->verdict.chain);
 264                 if (err < 0)
 265                         return err;
 266                 pctx->level--;
 267                 break;
 268         default:
 269                 break;
 270         }
 271
 272         return 0;
 273 }
 274
 275 static int nft_immediate_offload_verdict(struct nft_offload_ctx *ctx,
 276                                          struct nft_flow_rule *flow,
 277                                          const struct nft_immediate_expr *priv)
 278 {
 279         struct flow_action_entry *entry;
 280         const struct nft_data *data;
 281
 282         entry = &flow->rule->action.entries[ctx->num_actions++];
 283
 284         data = &priv->data;
 285         switch (data->verdict.code) {
 286         case NF_ACCEPT:
 287                 entry->id = FLOW_ACTION_ACCEPT;
 288                 break;
 289         case NF_DROP:
 290                 entry->id = FLOW_ACTION_DROP;
 291                 break;
 292         default:
 293                 return -EOPNOTSUPP;
 294         }
 295
 296         return 0;
 297 }
 298
 299 static int nft_immediate_offload(struct nft_offload_ctx *ctx,
 300                                  struct nft_flow_rule *flow,
 301                                  const struct nft_expr *expr)
 302 {
 303         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 304
 305         if (priv->dreg == NFT_REG_VERDICT)
 306                 return nft_immediate_offload_verdict(ctx, flow, priv);
 307
 308         memcpy(&ctx->regs[priv->dreg].data, &priv->data, sizeof(priv->data));
 309
 310         return 0;
 311 }
 312
 313 static bool nft_immediate_offload_action(const struct nft_expr *expr)
 314 {
 315         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 316
 317         if (priv->dreg == NFT_REG_VERDICT)
 318                 return true;
 319
 320         return false;
 321 }
 322
 323 static bool nft_immediate_reduce(struct nft_regs_track *track,
 324                                  const struct nft_expr *expr)
 325 {
 326         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 327
 328         if (priv->dreg != NFT_REG_VERDICT)
 329                 nft_reg_track_cancel(track, priv->dreg, priv->dlen);
 330
 331         return false;
 332 }
 333
 334 static const struct nft_expr_ops nft_imm_ops = {
 335         .type           = &nft_imm_type,
 336         .size           = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
 337         .eval           = nft_immediate_eval,
 338         .init           = nft_immediate_init,
 339         .activate       = nft_immediate_activate,
 340         .deactivate     = nft_immediate_deactivate,
 341         .destroy        = nft_immediate_destroy,
 342         .dump           = nft_immediate_dump,
 343         .validate       = nft_immediate_validate,
 344         .reduce         = nft_immediate_reduce,
 345         .offload        = nft_immediate_offload,
 346         .offload_action = nft_immediate_offload_action,
 347 };
 348
 349 struct nft_expr_type nft_imm_type __read_mostly = {
 350         .name           = "immediate",
 351         .ops            = &nft_imm_ops,
 352         .policy         = nft_immediate_policy,
 353         .maxattr        = NFTA_IMMEDIATE_MAX,
 354         .owner          = THIS_MODULE,
 355 };