net/netfilter/nft_dup_netdev.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
0004  */
0005
0006 #include <linux/kernel.h>
0007 #include <linux/init.h>
0008 #include <linux/module.h>
0009 #include <linux/netlink.h>
0010 #include <linux/netfilter.h>
0011 #include <linux/netfilter/nf_tables.h>
0012 #include <net/netfilter/nf_tables.h>
0013 #include <net/netfilter/nf_tables_offload.h>
0014 #include <net/netfilter/nf_dup_netdev.h>
0015
0016 struct nft_dup_netdev {
0017     u8  sreg_dev;
0018 };
0019
0020 static void nft_dup_netdev_eval(const struct nft_expr *expr,
0021                 struct nft_regs *regs,
0022                 const struct nft_pktinfo *pkt)
0023 {
0024     struct nft_dup_netdev *priv = nft_expr_priv(expr);
0025     int oif = regs->data[priv->sreg_dev];
0026
0027     nf_dup_netdev_egress(pkt, oif);
0028 }
0029
0030 static const struct nla_policy nft_dup_netdev_policy[NFTA_DUP_MAX + 1] = {
0031     [NFTA_DUP_SREG_DEV] = { .type = NLA_U32 },
0032 };
0033
0034 static int nft_dup_netdev_init(const struct nft_ctx *ctx,
0035                    const struct nft_expr *expr,
0036                    const struct nlattr * const tb[])
0037 {
0038     struct nft_dup_netdev *priv = nft_expr_priv(expr);
0039
0040     if (tb[NFTA_DUP_SREG_DEV] == NULL)
0041         return -EINVAL;
0042
0043     return nft_parse_register_load(tb[NFTA_DUP_SREG_DEV], &priv->sreg_dev,
0044                        sizeof(int));
0045 }
0046
0047 static int nft_dup_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)
0048 {
0049     struct nft_dup_netdev *priv = nft_expr_priv(expr);
0050
0051     if (nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
0052         goto nla_put_failure;
0053
0054     return 0;
0055
0056 nla_put_failure:
0057     return -1;
0058 }
0059
0060 static int nft_dup_netdev_offload(struct nft_offload_ctx *ctx,
0061                   struct nft_flow_rule *flow,
0062                   const struct nft_expr *expr)
0063 {
0064     const struct nft_dup_netdev *priv = nft_expr_priv(expr);
0065     int oif = ctx->regs[priv->sreg_dev].data.data[0];
0066
0067     return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_MIRRED, oif);
0068 }
0069
0070 static bool nft_dup_netdev_offload_action(const struct nft_expr *expr)
0071 {
0072     return true;
0073 }
0074
0075 static struct nft_expr_type nft_dup_netdev_type;
0076 static const struct nft_expr_ops nft_dup_netdev_ops = {
0077     .type       = &nft_dup_netdev_type,
0078     .size       = NFT_EXPR_SIZE(sizeof(struct nft_dup_netdev)),
0079     .eval       = nft_dup_netdev_eval,
0080     .init       = nft_dup_netdev_init,
0081     .dump       = nft_dup_netdev_dump,
0082     .reduce     = NFT_REDUCE_READONLY,
0083     .offload    = nft_dup_netdev_offload,
0084     .offload_action = nft_dup_netdev_offload_action,
0085 };
0086
0087 static struct nft_expr_type nft_dup_netdev_type __read_mostly = {
0088     .family     = NFPROTO_NETDEV,
0089     .name       = "dup",
0090     .ops        = &nft_dup_netdev_ops,
0091     .policy     = nft_dup_netdev_policy,
0092     .maxattr    = NFTA_DUP_MAX,
0093     .owner      = THIS_MODULE,
0094 };
0095
0096 static int __init nft_dup_netdev_module_init(void)
0097 {
0098     return nft_register_expr(&nft_dup_netdev_type);
0099 }
0100
0101 static void __exit nft_dup_netdev_module_exit(void)
0102 {
0103     nft_unregister_expr(&nft_dup_netdev_type);
0104 }
0105
0106 module_init(nft_dup_netdev_module_init);
0107 module_exit(nft_dup_netdev_module_exit);
0108
0109 MODULE_LICENSE("GPL");
0110 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
0111 MODULE_ALIAS_NFT_AF_EXPR(5, "dup");
0112 MODULE_DESCRIPTION("nftables netdev packet duplication support");