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_regs *regs,
  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         u32 *dest = &regs->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, p->br->dev->name, IFNAMSIZ);
  44         return;
  45 out:
  46         return nft_meta_get_eval(expr, regs, pkt);
  47 err:
  48         regs->verdict.code = 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
  58         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
  59         switch (priv->key) {
  60         case NFT_META_BRI_IIFNAME:
  61         case NFT_META_BRI_OIFNAME:
  62                 len = IFNAMSIZ;
  63                 break;
  64         default:
  65                 return nft_meta_get_init(ctx, expr, tb);
  66         }
  67
  68         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
  69         return nft_validate_register_store(ctx, priv->dreg, NULL,
  70                                            NFT_DATA_VALUE, len);
  71 }
  72
  73 static struct nft_expr_type nft_meta_bridge_type;
  74 static const struct nft_expr_ops nft_meta_bridge_get_ops = {
  75         .type           = &nft_meta_bridge_type,
  76         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
  77         .eval           = nft_meta_bridge_get_eval,
  78         .init           = nft_meta_bridge_get_init,
  79         .dump           = nft_meta_get_dump,
  80 };
  81
  82 static const struct nft_expr_ops nft_meta_bridge_set_ops = {
  83         .type           = &nft_meta_bridge_type,
  84         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
  85         .eval           = nft_meta_set_eval,
  86         .init           = nft_meta_set_init,
  87         .destroy        = nft_meta_set_destroy,
  88         .dump           = nft_meta_set_dump,
  89 };
  90
  91 static const struct nft_expr_ops *
  92 nft_meta_bridge_select_ops(const struct nft_ctx *ctx,
  93                            const struct nlattr * const tb[])
  94 {
  95         if (tb[NFTA_META_KEY] == NULL)
  96                 return ERR_PTR(-EINVAL);
  97
  98         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
  99                 return ERR_PTR(-EINVAL);
 100
 101         if (tb[NFTA_META_DREG])
 102                 return &nft_meta_bridge_get_ops;
 103
 104         if (tb[NFTA_META_SREG])
 105                 return &nft_meta_bridge_set_ops;
 106
 107         return ERR_PTR(-EINVAL);
 108 }
 109
 110 static struct nft_expr_type nft_meta_bridge_type __read_mostly = {
 111         .family         = NFPROTO_BRIDGE,
 112         .name           = "meta",
 113         .select_ops     = &nft_meta_bridge_select_ops,
 114         .policy         = nft_meta_policy,
 115         .maxattr        = NFTA_META_MAX,
 116         .owner          = THIS_MODULE,
 117 };
 118
 119 static int __init nft_meta_bridge_module_init(void)
 120 {
 121         return nft_register_expr(&nft_meta_bridge_type);
 122 }
 123
 124 static void __exit nft_meta_bridge_module_exit(void)
 125 {
 126         nft_unregister_expr(&nft_meta_bridge_type);
 127 }
 128
 129 module_init(nft_meta_bridge_module_init);
 130 module_exit(nft_meta_bridge_module_exit);
 131
 132 MODULE_LICENSE("GPL");
 133 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
 134 MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "meta");