net/bridge/netfilter/nft_reject_bridge.c

   1 /*
   2  * Copyright (c) 2014 Pablo Neira Ayuso <pablo@netfilter.org>
   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 #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.h>
  16 #include <net/netfilter/nft_reject.h>
  17 #include <net/netfilter/ipv4/nf_reject.h>
  18 #include <net/netfilter/ipv6/nf_reject.h>
  19
  20 static void nft_reject_bridge_eval(const struct nft_expr *expr,
  21                                  struct nft_data data[NFT_REG_MAX + 1],
  22                                  const struct nft_pktinfo *pkt)
  23 {
  24         struct nft_reject *priv = nft_expr_priv(expr);
  25         struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
  26
  27         switch (eth_hdr(pkt->skb)->h_proto) {
  28         case htons(ETH_P_IP):
  29                 switch (priv->type) {
  30                 case NFT_REJECT_ICMP_UNREACH:
  31                         nf_send_unreach(pkt->skb, priv->icmp_code);
  32                         break;
  33                 case NFT_REJECT_TCP_RST:
  34                         nf_send_reset(pkt->skb, pkt->ops->hooknum);
  35                         break;
  36                 case NFT_REJECT_ICMPX_UNREACH:
  37                         nf_send_unreach(pkt->skb,
  38                                         nft_reject_icmp_code(priv->icmp_code));
  39                         break;
  40                 }
  41                 break;
  42         case htons(ETH_P_IPV6):
  43                 switch (priv->type) {
  44                 case NFT_REJECT_ICMP_UNREACH:
  45                         nf_send_unreach6(net, pkt->skb, priv->icmp_code,
  46                                          pkt->ops->hooknum);
  47                         break;
  48                 case NFT_REJECT_TCP_RST:
  49                         nf_send_reset6(net, pkt->skb, pkt->ops->hooknum);
  50                         break;
  51                 case NFT_REJECT_ICMPX_UNREACH:
  52                         nf_send_unreach6(net, pkt->skb,
  53                                          nft_reject_icmpv6_code(priv->icmp_code),
  54                                          pkt->ops->hooknum);
  55                         break;
  56                 }
  57                 break;
  58         default:
  59                 /* No explicit way to reject this protocol, drop it. */
  60                 break;
  61         }
  62         data[NFT_REG_VERDICT].verdict = NF_DROP;
  63 }
  64
  65 static int nft_reject_bridge_init(const struct nft_ctx *ctx,
  66                                   const struct nft_expr *expr,
  67                                   const struct nlattr * const tb[])
  68 {
  69         struct nft_reject *priv = nft_expr_priv(expr);
  70         int icmp_code;
  71
  72         if (tb[NFTA_REJECT_TYPE] == NULL)
  73                 return -EINVAL;
  74
  75         priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  76         switch (priv->type) {
  77         case NFT_REJECT_ICMP_UNREACH:
  78         case NFT_REJECT_ICMPX_UNREACH:
  79                 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  80                         return -EINVAL;
  81
  82                 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  83                 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  84                     icmp_code > NFT_REJECT_ICMPX_MAX)
  85                         return -EINVAL;
  86
  87                 priv->icmp_code = icmp_code;
  88                 break;
  89         case NFT_REJECT_TCP_RST:
  90                 break;
  91         default:
  92                 return -EINVAL;
  93         }
  94         return 0;
  95 }
  96
  97 static int nft_reject_bridge_dump(struct sk_buff *skb,
  98                                   const struct nft_expr *expr)
  99 {
 100         const struct nft_reject *priv = nft_expr_priv(expr);
 101
 102         if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
 103                 goto nla_put_failure;
 104
 105         switch (priv->type) {
 106         case NFT_REJECT_ICMP_UNREACH:
 107         case NFT_REJECT_ICMPX_UNREACH:
 108                 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
 109                         goto nla_put_failure;
 110                 break;
 111         }
 112
 113         return 0;
 114
 115 nla_put_failure:
 116         return -1;
 117 }
 118
 119 static struct nft_expr_type nft_reject_bridge_type;
 120 static const struct nft_expr_ops nft_reject_bridge_ops = {
 121         .type           = &nft_reject_bridge_type,
 122         .size           = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
 123         .eval           = nft_reject_bridge_eval,
 124         .init           = nft_reject_bridge_init,
 125         .dump           = nft_reject_bridge_dump,
 126 };
 127
 128 static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
 129         .family         = NFPROTO_BRIDGE,
 130         .name           = "reject",
 131         .ops            = &nft_reject_bridge_ops,
 132         .policy         = nft_reject_policy,
 133         .maxattr        = NFTA_REJECT_MAX,
 134         .owner          = THIS_MODULE,
 135 };
 136
 137 static int __init nft_reject_bridge_module_init(void)
 138 {
 139         return nft_register_expr(&nft_reject_bridge_type);
 140 }
 141
 142 static void __exit nft_reject_bridge_module_exit(void)
 143 {
 144         nft_unregister_expr(&nft_reject_bridge_type);
 145 }
 146
 147 module_init(nft_reject_bridge_module_init);
 148 module_exit(nft_reject_bridge_module_exit);
 149
 150 MODULE_LICENSE("GPL");
 151 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 152 MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");