net/bridge/netfilter/nft_meta_bridge.c

   1 /*
   2  * Copyright (c) 2014 Intel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/netlink.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables.h>
  17 #include <net/netfilter/nft_meta.h>
  18
  19 #include "../br_private.h"
  20
  21 static void nft_meta_bridge_get_eval(const struct nft_expr *expr,
  22                                      struct nft_data data[NFT_REG_MAX + 1],
  23                                      const struct nft_pktinfo *pkt)
  24 {
  25         const struct nft_meta *priv = nft_expr_priv(expr);
  26         const struct net_device *in = pkt->in, *out = pkt->out;
  27         struct nft_data *dest = &data[priv->dreg];
  28         const struct net_bridge_port *p;
  29
  30         switch (priv->key) {
  31         case NFT_META_BRI_IIFNAME:
  32                 if (in == NULL || (p = br_port_get_rcu(in)) == NULL)
  33                         goto err;
  34                 break;
  35         case NFT_META_BRI_OIFNAME:
  36                 if (out == NULL || (p = br_port_get_rcu(out)) == NULL)
  37                         goto err;
  38                 break;
  39         default:
  40                 goto out;
  41         }
  42
  43         strncpy((char *)dest->data, p->br->dev->name, sizeof(dest->data));
  44         return;
  45 out:
  46         return nft_meta_get_eval(expr, data, pkt);
  47 err:
  48         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
  49 }
  50
  51 static int nft_meta_bridge_get_init(const struct nft_ctx *ctx,
  52                                     const struct nft_expr *expr,
  53                                     const struct nlattr * const tb[])
  54 {
  55         struct nft_meta *priv = nft_expr_priv(expr);
  56         unsigned int len;
  57         int err;
  58
  59         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
  60         switch (priv->key) {
  61         case NFT_META_BRI_IIFNAME:
  62         case NFT_META_BRI_OIFNAME:
  63                 len = IFNAMSIZ;
  64                 break;
  65         default:
  66                 return nft_meta_get_init(ctx, expr, tb);
  67         }
  68
  69         priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
  70         err = nft_validate_output_register(priv->dreg);
  71         if (err < 0)
  72                 return err;
  73
  74         err = nft_validate_data_load(ctx, priv->dreg, NULL,
  75                                      NFT_DATA_VALUE, len);
  76         if (err < 0)
  77                 return err;
  78
  79         return 0;
  80 }
  81
  82 static struct nft_expr_type nft_meta_bridge_type;
  83 static const struct nft_expr_ops nft_meta_bridge_get_ops = {
  84         .type           = &nft_meta_bridge_type,
  85         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
  86         .eval           = nft_meta_bridge_get_eval,
  87         .init           = nft_meta_bridge_get_init,
  88         .dump           = nft_meta_get_dump,
  89 };
  90
  91 static const struct nft_expr_ops nft_meta_bridge_set_ops = {
  92         .type           = &nft_meta_bridge_type,
  93         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
  94         .eval           = nft_meta_set_eval,
  95         .init           = nft_meta_set_init,
  96         .dump           = nft_meta_set_dump,
  97 };
  98
  99 static const struct nft_expr_ops *
 100 nft_meta_bridge_select_ops(const struct nft_ctx *ctx,
 101                            const struct nlattr * const tb[])
 102 {
 103         if (tb[NFTA_META_KEY] == NULL)
 104                 return ERR_PTR(-EINVAL);
 105
 106         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 107                 return ERR_PTR(-EINVAL);
 108
 109         if (tb[NFTA_META_DREG])
 110                 return &nft_meta_bridge_get_ops;
 111
 112         if (tb[NFTA_META_SREG])
 113                 return &nft_meta_bridge_set_ops;
 114
 115         return ERR_PTR(-EINVAL);
 116 }
 117
 118 static struct nft_expr_type nft_meta_bridge_type __read_mostly = {
 119         .family         = NFPROTO_BRIDGE,
 120         .name           = "meta",
 121         .select_ops     = &nft_meta_bridge_select_ops,
 122         .policy         = nft_meta_policy,
 123         .maxattr        = NFTA_META_MAX,
 124         .owner          = THIS_MODULE,
 125 };
 126
 127 static int __init nft_meta_bridge_module_init(void)
 128 {
 129         return nft_register_expr(&nft_meta_bridge_type);
 130 }
 131
 132 static void __exit nft_meta_bridge_module_exit(void)
 133 {
 134         nft_unregister_expr(&nft_meta_bridge_type);
 135 }
 136
 137 module_init(nft_meta_bridge_module_init);
 138 module_exit(nft_meta_bridge_module_exit);
 139
 140 MODULE_LICENSE("GPL");
 141 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
 142 MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "meta");