net/netfilter/nft_fib.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Generic part shared by ipv4 and ipv6 backends.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/init.h>
   9 #include <linux/module.h>
  10 #include <linux/netlink.h>
  11 #include <linux/netfilter.h>
  12 #include <linux/netfilter/nf_tables.h>
  13 #include <net/netfilter/nf_tables_core.h>
  14 #include <net/netfilter/nf_tables.h>
  15 #include <net/netfilter/nft_fib.h>
  16
  17 #define NFTA_FIB_F_ALL (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR | \
  18                         NFTA_FIB_F_MARK | NFTA_FIB_F_IIF | NFTA_FIB_F_OIF | \
  19                         NFTA_FIB_F_PRESENT)
  20
  21 const struct nla_policy nft_fib_policy[NFTA_FIB_MAX + 1] = {
  22         [NFTA_FIB_DREG]         = { .type = NLA_U32 },
  23         [NFTA_FIB_RESULT]       = { .type = NLA_U32 },
  24         [NFTA_FIB_FLAGS]        =
  25                 NLA_POLICY_MASK(NLA_BE32, NFTA_FIB_F_ALL),
  26 };
  27 EXPORT_SYMBOL(nft_fib_policy);
  28
  29 int nft_fib_validate(const struct nft_ctx *ctx, const struct nft_expr *expr)
  30 {
  31         const struct nft_fib *priv = nft_expr_priv(expr);
  32         unsigned int hooks;
  33
  34         switch (priv->result) {
  35         case NFT_FIB_RESULT_OIF:
  36         case NFT_FIB_RESULT_OIFNAME:
  37                 hooks = (1 << NF_INET_PRE_ROUTING) |
  38                         (1 << NF_INET_LOCAL_IN) |
  39                         (1 << NF_INET_FORWARD);
  40                 break;
  41         case NFT_FIB_RESULT_ADDRTYPE:
  42                 if (priv->flags & NFTA_FIB_F_IIF)
  43                         hooks = (1 << NF_INET_PRE_ROUTING) |
  44                                 (1 << NF_INET_LOCAL_IN) |
  45                                 (1 << NF_INET_FORWARD);
  46                 else if (priv->flags & NFTA_FIB_F_OIF)
  47                         hooks = (1 << NF_INET_LOCAL_OUT) |
  48                                 (1 << NF_INET_POST_ROUTING) |
  49                                 (1 << NF_INET_FORWARD);
  50                 else
  51                         hooks = (1 << NF_INET_LOCAL_IN) |
  52                                 (1 << NF_INET_LOCAL_OUT) |
  53                                 (1 << NF_INET_FORWARD) |
  54                                 (1 << NF_INET_PRE_ROUTING) |
  55                                 (1 << NF_INET_POST_ROUTING);
  56
  57                 break;
  58         default:
  59                 return -EINVAL;
  60         }
  61
  62         return nft_chain_validate_hooks(ctx->chain, hooks);
  63 }
  64 EXPORT_SYMBOL_GPL(nft_fib_validate);
  65
  66 int nft_fib_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
  67                  const struct nlattr * const tb[])
  68 {
  69         struct nft_fib *priv = nft_expr_priv(expr);
  70         unsigned int len;
  71         int err;
  72
  73         if (!tb[NFTA_FIB_DREG] || !tb[NFTA_FIB_RESULT] || !tb[NFTA_FIB_FLAGS])
  74                 return -EINVAL;
  75
  76         priv->flags = ntohl(nla_get_be32(tb[NFTA_FIB_FLAGS]));
  77
  78         if (priv->flags == 0)
  79                 return -EINVAL;
  80
  81         if ((priv->flags & (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR)) ==
  82                            (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR))
  83                 return -EINVAL;
  84         if ((priv->flags & (NFTA_FIB_F_IIF | NFTA_FIB_F_OIF)) ==
  85                            (NFTA_FIB_F_IIF | NFTA_FIB_F_OIF))
  86                 return -EINVAL;
  87         if ((priv->flags & (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR)) == 0)
  88                 return -EINVAL;
  89
  90         priv->result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
  91
  92         switch (priv->result) {
  93         case NFT_FIB_RESULT_OIF:
  94                 if (priv->flags & NFTA_FIB_F_OIF)
  95                         return -EINVAL;
  96                 len = sizeof(int);
  97                 break;
  98         case NFT_FIB_RESULT_OIFNAME:
  99                 if (priv->flags & NFTA_FIB_F_OIF)
 100                         return -EINVAL;
 101                 len = IFNAMSIZ;
 102                 break;
 103         case NFT_FIB_RESULT_ADDRTYPE:
 104                 len = sizeof(u32);
 105                 break;
 106         default:
 107                 return -EINVAL;
 108         }
 109
 110         err = nft_parse_register_store(ctx, tb[NFTA_FIB_DREG], &priv->dreg,
 111                                        NULL, NFT_DATA_VALUE, len);
 112         if (err < 0)
 113                 return err;
 114
 115         return 0;
 116 }
 117 EXPORT_SYMBOL_GPL(nft_fib_init);
 118
 119 int nft_fib_dump(struct sk_buff *skb, const struct nft_expr *expr, bool reset)
 120 {
 121         const struct nft_fib *priv = nft_expr_priv(expr);
 122
 123         if (nft_dump_register(skb, NFTA_FIB_DREG, priv->dreg))
 124                 return -1;
 125
 126         if (nla_put_be32(skb, NFTA_FIB_RESULT, htonl(priv->result)))
 127                 return -1;
 128
 129         if (nla_put_be32(skb, NFTA_FIB_FLAGS, htonl(priv->flags)))
 130                 return -1;
 131
 132         return 0;
 133 }
 134 EXPORT_SYMBOL_GPL(nft_fib_dump);
 135
 136 void nft_fib_store_result(void *reg, const struct nft_fib *priv,
 137                           const struct net_device *dev)
 138 {
 139         u32 *dreg = reg;
 140         int index;
 141
 142         switch (priv->result) {
 143         case NFT_FIB_RESULT_OIF:
 144                 index = dev ? dev->ifindex : 0;
 145                 if (priv->flags & NFTA_FIB_F_PRESENT)
 146                         nft_reg_store8(dreg, !!index);
 147                 else
 148                         *dreg = index;
 149
 150                 break;
 151         case NFT_FIB_RESULT_OIFNAME:
 152                 if (priv->flags & NFTA_FIB_F_PRESENT)
 153                         nft_reg_store8(dreg, !!dev);
 154                 else
 155                         strscpy_pad(reg, dev ? dev->name : "", IFNAMSIZ);
 156                 break;
 157         default:
 158                 WARN_ON_ONCE(1);
 159                 *dreg = 0;
 160                 break;
 161         }
 162 }
 163 EXPORT_SYMBOL_GPL(nft_fib_store_result);
 164
 165 bool nft_fib_reduce(struct nft_regs_track *track,
 166                     const struct nft_expr *expr)
 167 {
 168         const struct nft_fib *priv = nft_expr_priv(expr);
 169         unsigned int len = NFT_REG32_SIZE;
 170         const struct nft_fib *fib;
 171
 172         switch (priv->result) {
 173         case NFT_FIB_RESULT_OIF:
 174                 break;
 175         case NFT_FIB_RESULT_OIFNAME:
 176                 if (priv->flags & NFTA_FIB_F_PRESENT)
 177                         len = NFT_REG32_SIZE;
 178                 else
 179                         len = IFNAMSIZ;
 180                 break;
 181         case NFT_FIB_RESULT_ADDRTYPE:
 182              break;
 183         default:
 184                 WARN_ON_ONCE(1);
 185                 break;
 186         }
 187
 188         if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
 189                 nft_reg_track_update(track, expr, priv->dreg, len);
 190                 return false;
 191         }
 192
 193         fib = nft_expr_priv(track->regs[priv->dreg].selector);
 194         if (priv->result != fib->result ||
 195             priv->flags != fib->flags) {
 196                 nft_reg_track_update(track, expr, priv->dreg, len);
 197                 return false;
 198         }
 199
 200         if (!track->regs[priv->dreg].bitwise)
 201                 return true;
 202
 203         return false;
 204 }
 205 EXPORT_SYMBOL_GPL(nft_fib_reduce);
 206
 207 MODULE_LICENSE("GPL");
 208 MODULE_DESCRIPTION("Query routing table from nftables");
 209 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");