net/netfilter/nft_fib.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * Generic part shared by ipv4 and ipv6 backends.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables_core.h>
  16 #include <net/netfilter/nf_tables.h>
  17 #include <net/netfilter/nft_fib.h>
  18
  19 const struct nla_policy nft_fib_policy[NFTA_FIB_MAX + 1] = {
  20         [NFTA_FIB_DREG]         = { .type = NLA_U32 },
  21         [NFTA_FIB_RESULT]       = { .type = NLA_U32 },
  22         [NFTA_FIB_FLAGS]        = { .type = NLA_U32 },
  23 };
  24 EXPORT_SYMBOL(nft_fib_policy);
  25
  26 #define NFTA_FIB_F_ALL (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR | \
  27                         NFTA_FIB_F_MARK | NFTA_FIB_F_IIF | NFTA_FIB_F_OIF | \
  28                         NFTA_FIB_F_PRESENT)
  29
  30 int nft_fib_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
  31                      const struct nft_data **data)
  32 {
  33         const struct nft_fib *priv = nft_expr_priv(expr);
  34         unsigned int hooks;
  35
  36         switch (priv->result) {
  37         case NFT_FIB_RESULT_OIF: /* fallthrough */
  38         case NFT_FIB_RESULT_OIFNAME:
  39                 hooks = (1 << NF_INET_PRE_ROUTING);
  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 || (priv->flags & ~NFTA_FIB_F_ALL))
  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         priv->dreg = nft_parse_register(tb[NFTA_FIB_DREG]);
  92
  93         switch (priv->result) {
  94         case NFT_FIB_RESULT_OIF:
  95                 if (priv->flags & NFTA_FIB_F_OIF)
  96                         return -EINVAL;
  97                 len = sizeof(int);
  98                 break;
  99         case NFT_FIB_RESULT_OIFNAME:
 100                 if (priv->flags & NFTA_FIB_F_OIF)
 101                         return -EINVAL;
 102                 len = IFNAMSIZ;
 103                 break;
 104         case NFT_FIB_RESULT_ADDRTYPE:
 105                 len = sizeof(u32);
 106                 break;
 107         default:
 108                 return -EINVAL;
 109         }
 110
 111         err = nft_validate_register_store(ctx, priv->dreg, NULL,
 112                                           NFT_DATA_VALUE, len);
 113         if (err < 0)
 114                 return err;
 115
 116         return 0;
 117 }
 118 EXPORT_SYMBOL_GPL(nft_fib_init);
 119
 120 int nft_fib_dump(struct sk_buff *skb, const struct nft_expr *expr)
 121 {
 122         const struct nft_fib *priv = nft_expr_priv(expr);
 123
 124         if (nft_dump_register(skb, NFTA_FIB_DREG, priv->dreg))
 125                 return -1;
 126
 127         if (nla_put_be32(skb, NFTA_FIB_RESULT, htonl(priv->result)))
 128                 return -1;
 129
 130         if (nla_put_be32(skb, NFTA_FIB_FLAGS, htonl(priv->flags)))
 131                 return -1;
 132
 133         return 0;
 134 }
 135 EXPORT_SYMBOL_GPL(nft_fib_dump);
 136
 137 void nft_fib_store_result(void *reg, const struct nft_fib *priv,
 138                           const struct nft_pktinfo *pkt, int index)
 139 {
 140         struct net_device *dev;
 141         u32 *dreg = reg;
 142
 143         switch (priv->result) {
 144         case NFT_FIB_RESULT_OIF:
 145                 *dreg = (priv->flags & NFTA_FIB_F_PRESENT) ? !!index : index;
 146                 break;
 147         case NFT_FIB_RESULT_OIFNAME:
 148                 dev = dev_get_by_index_rcu(nft_net(pkt), index);
 149                 if (priv->flags & NFTA_FIB_F_PRESENT)
 150                         *dreg = !!dev;
 151                 else
 152                         strncpy(reg, dev ? dev->name : "", IFNAMSIZ);
 153                 break;
 154         default:
 155                 WARN_ON_ONCE(1);
 156                 *dreg = 0;
 157                 break;
 158         }
 159 }
 160 EXPORT_SYMBOL_GPL(nft_fib_store_result);
 161
 162 MODULE_LICENSE("GPL");
 163 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");