// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_offload.h>
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#include <net/netfilter/nf_dup_netdev.h>
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#include <net/neighbour.h>
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#include <net/ip.h>
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struct nft_fwd_netdev {
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u8 sreg_dev;
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};
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static void nft_fwd_netdev_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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struct nft_fwd_netdev *priv = nft_expr_priv(expr);
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int oif = regs->data[priv->sreg_dev];
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/* This is used by ifb only. */
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skb_set_redirected(pkt->skb, true);
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nf_fwd_netdev_egress(pkt, oif);
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regs->verdict.code = NF_STOLEN;
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}
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static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = {
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[NFTA_FWD_SREG_DEV] = { .type = NLA_U32 },
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[NFTA_FWD_SREG_ADDR] = { .type = NLA_U32 },
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[NFTA_FWD_NFPROTO] = { .type = NLA_U32 },
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};
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static int nft_fwd_netdev_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_fwd_netdev *priv = nft_expr_priv(expr);
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if (tb[NFTA_FWD_SREG_DEV] == NULL)
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return -EINVAL;
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return nft_parse_register_load(tb[NFTA_FWD_SREG_DEV], &priv->sreg_dev,
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sizeof(int));
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}
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static int nft_fwd_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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struct nft_fwd_netdev *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static int nft_fwd_netdev_offload(struct nft_offload_ctx *ctx,
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struct nft_flow_rule *flow,
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const struct nft_expr *expr)
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{
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const struct nft_fwd_netdev *priv = nft_expr_priv(expr);
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int oif = ctx->regs[priv->sreg_dev].data.data[0];
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return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_REDIRECT, oif);
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}
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static bool nft_fwd_netdev_offload_action(const struct nft_expr *expr)
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{
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return true;
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}
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struct nft_fwd_neigh {
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u8 sreg_dev;
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u8 sreg_addr;
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u8 nfproto;
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};
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static void nft_fwd_neigh_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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struct nft_fwd_neigh *priv = nft_expr_priv(expr);
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void *addr = ®s->data[priv->sreg_addr];
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int oif = regs->data[priv->sreg_dev];
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unsigned int verdict = NF_STOLEN;
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struct sk_buff *skb = pkt->skb;
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struct net_device *dev;
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int neigh_table;
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switch (priv->nfproto) {
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case NFPROTO_IPV4: {
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struct iphdr *iph;
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if (skb->protocol != htons(ETH_P_IP)) {
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verdict = NFT_BREAK;
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goto out;
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}
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if (skb_try_make_writable(skb, sizeof(*iph))) {
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verdict = NF_DROP;
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goto out;
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}
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iph = ip_hdr(skb);
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ip_decrease_ttl(iph);
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neigh_table = NEIGH_ARP_TABLE;
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break;
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}
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case NFPROTO_IPV6: {
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struct ipv6hdr *ip6h;
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if (skb->protocol != htons(ETH_P_IPV6)) {
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verdict = NFT_BREAK;
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goto out;
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}
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if (skb_try_make_writable(skb, sizeof(*ip6h))) {
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verdict = NF_DROP;
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goto out;
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}
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ip6h = ipv6_hdr(skb);
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ip6h->hop_limit--;
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neigh_table = NEIGH_ND_TABLE;
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break;
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}
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default:
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verdict = NFT_BREAK;
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goto out;
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}
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dev = dev_get_by_index_rcu(nft_net(pkt), oif);
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if (dev == NULL)
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return;
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skb->dev = dev;
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skb->tstamp = 0;
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neigh_xmit(neigh_table, dev, addr, skb);
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out:
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regs->verdict.code = verdict;
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}
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static int nft_fwd_neigh_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_fwd_neigh *priv = nft_expr_priv(expr);
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unsigned int addr_len;
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int err;
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if (!tb[NFTA_FWD_SREG_DEV] ||
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!tb[NFTA_FWD_SREG_ADDR] ||
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!tb[NFTA_FWD_NFPROTO])
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return -EINVAL;
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priv->nfproto = ntohl(nla_get_be32(tb[NFTA_FWD_NFPROTO]));
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switch (priv->nfproto) {
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case NFPROTO_IPV4:
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addr_len = sizeof(struct in_addr);
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break;
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case NFPROTO_IPV6:
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addr_len = sizeof(struct in6_addr);
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break;
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default:
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return -EOPNOTSUPP;
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}
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err = nft_parse_register_load(tb[NFTA_FWD_SREG_DEV], &priv->sreg_dev,
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sizeof(int));
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if (err < 0)
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return err;
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return nft_parse_register_load(tb[NFTA_FWD_SREG_ADDR], &priv->sreg_addr,
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addr_len);
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}
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static int nft_fwd_neigh_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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struct nft_fwd_neigh *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev) ||
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nft_dump_register(skb, NFTA_FWD_SREG_ADDR, priv->sreg_addr) ||
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nla_put_be32(skb, NFTA_FWD_NFPROTO, htonl(priv->nfproto)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static int nft_fwd_validate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nft_data **data)
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{
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return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS));
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}
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static struct nft_expr_type nft_fwd_netdev_type;
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static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
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.type = &nft_fwd_netdev_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_neigh)),
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.eval = nft_fwd_neigh_eval,
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.init = nft_fwd_neigh_init,
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.dump = nft_fwd_neigh_dump,
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.validate = nft_fwd_validate,
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};
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static const struct nft_expr_ops nft_fwd_netdev_ops = {
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.type = &nft_fwd_netdev_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)),
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.eval = nft_fwd_netdev_eval,
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.init = nft_fwd_netdev_init,
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.dump = nft_fwd_netdev_dump,
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.validate = nft_fwd_validate,
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.offload = nft_fwd_netdev_offload,
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.offload_action = nft_fwd_netdev_offload_action,
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};
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static const struct nft_expr_ops *
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nft_fwd_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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if (tb[NFTA_FWD_SREG_ADDR])
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return &nft_fwd_neigh_netdev_ops;
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if (tb[NFTA_FWD_SREG_DEV])
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return &nft_fwd_netdev_ops;
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return ERR_PTR(-EOPNOTSUPP);
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}
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static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {
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.family = NFPROTO_NETDEV,
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.name = "fwd",
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.select_ops = nft_fwd_select_ops,
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.policy = nft_fwd_netdev_policy,
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.maxattr = NFTA_FWD_MAX,
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.owner = THIS_MODULE,
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};
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static int __init nft_fwd_netdev_module_init(void)
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{
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return nft_register_expr(&nft_fwd_netdev_type);
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}
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static void __exit nft_fwd_netdev_module_exit(void)
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{
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nft_unregister_expr(&nft_fwd_netdev_type);
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}
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module_init(nft_fwd_netdev_module_init);
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module_exit(nft_fwd_netdev_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
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MODULE_ALIAS_NFT_AF_EXPR(5, "fwd");
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