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 int nft_immediate_init(const struct nft_ctx *ctx,
  33                               const struct nft_expr *expr,
  34                               const struct nlattr * const tb[])
  35 {
  36         struct nft_immediate_expr *priv = nft_expr_priv(expr);
  37         struct nft_data_desc desc;
  38         int err;
  39
  40         if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
  41             tb[NFTA_IMMEDIATE_DATA] == NULL)
  42                 return -EINVAL;
  43
  44         err = nft_data_init(ctx, &priv->data, sizeof(priv->data), &desc,
  45                             tb[NFTA_IMMEDIATE_DATA]);
  46         if (err < 0)
  47                 return err;
  48
  49         priv->dlen = desc.len;
  50
  51         priv->dreg = nft_parse_register(tb[NFTA_IMMEDIATE_DREG]);
  52         err = nft_validate_register_store(ctx, priv->dreg, &priv->data,
  53                                           desc.type, desc.len);
  54         if (err < 0)
  55                 goto err1;
  56
  57         if (priv->dreg == NFT_REG_VERDICT) {
  58                 struct nft_chain *chain = priv->data.verdict.chain;
  59
  60                 switch (priv->data.verdict.code) {
  61                 case NFT_JUMP:
  62                 case NFT_GOTO:
  63                         if (nft_chain_is_bound(chain)) {
  64                                 err = -EBUSY;
  65                                 goto err1;
  66                         }
  67                         chain->bound = true;
  68                         break;
  69                 default:
  70                         break;
  71                 }
  72         }
  73
  74         return 0;
  75
  76 err1:
  77         nft_data_release(&priv->data, desc.type);
  78         return err;
  79 }
  80
  81 static void nft_immediate_activate(const struct nft_ctx *ctx,
  82                                    const struct nft_expr *expr)
  83 {
  84         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  85
  86         return nft_data_hold(&priv->data, nft_dreg_to_type(priv->dreg));
  87 }
  88
  89 static void nft_immediate_deactivate(const struct nft_ctx *ctx,
  90                                      const struct nft_expr *expr,
  91                                      enum nft_trans_phase phase)
  92 {
  93         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
  94
  95         if (phase == NFT_TRANS_COMMIT)
  96                 return;
  97
  98         return nft_data_release(&priv->data, nft_dreg_to_type(priv->dreg));
  99 }
 100
 101 static void nft_immediate_destroy(const struct nft_ctx *ctx,
 102                                   const struct nft_expr *expr)
 103 {
 104         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 105         const struct nft_data *data = &priv->data;
 106         struct nft_rule *rule, *n;
 107         struct nft_ctx chain_ctx;
 108         struct nft_chain *chain;
 109
 110         if (priv->dreg != NFT_REG_VERDICT)
 111                 return;
 112
 113         switch (data->verdict.code) {
 114         case NFT_JUMP:
 115         case NFT_GOTO:
 116                 chain = data->verdict.chain;
 117
 118                 if (!nft_chain_is_bound(chain))
 119                         break;
 120
 121                 chain_ctx = *ctx;
 122                 chain_ctx.chain = chain;
 123
 124                 list_for_each_entry_safe(rule, n, &chain->rules, list)
 125                         nf_tables_rule_release(&chain_ctx, rule);
 126
 127                 nf_tables_chain_destroy(&chain_ctx);
 128                 break;
 129         default:
 130                 break;
 131         }
 132 }
 133
 134 static int nft_immediate_dump(struct sk_buff *skb, const struct nft_expr *expr)
 135 {
 136         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 137
 138         if (nft_dump_register(skb, NFTA_IMMEDIATE_DREG, priv->dreg))
 139                 goto nla_put_failure;
 140
 141         return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
 142                              nft_dreg_to_type(priv->dreg), priv->dlen);
 143
 144 nla_put_failure:
 145         return -1;
 146 }
 147
 148 static int nft_immediate_validate(const struct nft_ctx *ctx,
 149                                   const struct nft_expr *expr,
 150                                   const struct nft_data **d)
 151 {
 152         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 153         struct nft_ctx *pctx = (struct nft_ctx *)ctx;
 154         const struct nft_data *data;
 155         int err;
 156
 157         if (priv->dreg != NFT_REG_VERDICT)
 158                 return 0;
 159
 160         data = &priv->data;
 161
 162         switch (data->verdict.code) {
 163         case NFT_JUMP:
 164         case NFT_GOTO:
 165                 pctx->level++;
 166                 err = nft_chain_validate(ctx, data->verdict.chain);
 167                 if (err < 0)
 168                         return err;
 169                 pctx->level--;
 170                 break;
 171         default:
 172                 break;
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int nft_immediate_offload_verdict(struct nft_offload_ctx *ctx,
 179                                          struct nft_flow_rule *flow,
 180                                          const struct nft_immediate_expr *priv)
 181 {
 182         struct flow_action_entry *entry;
 183         const struct nft_data *data;
 184
 185         entry = &flow->rule->action.entries[ctx->num_actions++];
 186
 187         data = &priv->data;
 188         switch (data->verdict.code) {
 189         case NF_ACCEPT:
 190                 entry->id = FLOW_ACTION_ACCEPT;
 191                 break;
 192         case NF_DROP:
 193                 entry->id = FLOW_ACTION_DROP;
 194                 break;
 195         default:
 196                 return -EOPNOTSUPP;
 197         }
 198
 199         return 0;
 200 }
 201
 202 static int nft_immediate_offload(struct nft_offload_ctx *ctx,
 203                                  struct nft_flow_rule *flow,
 204                                  const struct nft_expr *expr)
 205 {
 206         const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 207
 208         if (priv->dreg == NFT_REG_VERDICT)
 209                 return nft_immediate_offload_verdict(ctx, flow, priv);
 210
 211         memcpy(&ctx->regs[priv->dreg].data, &priv->data, sizeof(priv->data));
 212
 213         return 0;
 214 }
 215
 216 static const struct nft_expr_ops nft_imm_ops = {
 217         .type           = &nft_imm_type,
 218         .size           = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
 219         .eval           = nft_immediate_eval,
 220         .init           = nft_immediate_init,
 221         .activate       = nft_immediate_activate,
 222         .deactivate     = nft_immediate_deactivate,
 223         .destroy        = nft_immediate_destroy,
 224         .dump           = nft_immediate_dump,
 225         .validate       = nft_immediate_validate,
 226         .offload        = nft_immediate_offload,
 227         .offload_flags  = NFT_OFFLOAD_F_ACTION,
 228 };
 229
 230 struct nft_expr_type nft_imm_type __read_mostly = {
 231         .name           = "immediate",
 232         .ops            = &nft_imm_ops,
 233         .policy         = nft_immediate_policy,
 234         .maxattr        = NFTA_IMMEDIATE_MAX,
 235         .owner          = THIS_MODULE,
 236 };