| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org> |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/netlink.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/nf_tables.h> |
| #include <linux/ip.h> |
| #include <linux/ipv6.h> |
| #include <net/netfilter/nf_tables.h> |
| #include <net/netfilter/nf_tables_offload.h> |
| #include <net/netfilter/nf_dup_netdev.h> |
| #include <net/neighbour.h> |
| #include <net/ip.h> |
| |
| struct nft_fwd_netdev { |
| u8 sreg_dev; |
| }; |
| |
| static void nft_fwd_netdev_eval(const struct nft_expr *expr, |
| struct nft_regs *regs, |
| const struct nft_pktinfo *pkt) |
| { |
| struct nft_fwd_netdev *priv = nft_expr_priv(expr); |
| int oif = regs->data[priv->sreg_dev]; |
| struct sk_buff *skb = pkt->skb; |
| |
| /* This is used by ifb only. */ |
| skb->skb_iif = skb->dev->ifindex; |
| skb_set_redirected(skb, nft_hook(pkt) == NF_NETDEV_INGRESS); |
| |
| nf_fwd_netdev_egress(pkt, oif); |
| regs->verdict.code = NF_STOLEN; |
| } |
| |
| static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = { |
| [NFTA_FWD_SREG_DEV] = { .type = NLA_U32 }, |
| [NFTA_FWD_SREG_ADDR] = { .type = NLA_U32 }, |
| [NFTA_FWD_NFPROTO] = NLA_POLICY_MAX(NLA_BE32, 255), |
| }; |
| |
| static int nft_fwd_netdev_init(const struct nft_ctx *ctx, |
| const struct nft_expr *expr, |
| const struct nlattr * const tb[]) |
| { |
| struct nft_fwd_netdev *priv = nft_expr_priv(expr); |
| |
| if (tb[NFTA_FWD_SREG_DEV] == NULL) |
| return -EINVAL; |
| |
| return nft_parse_register_load(tb[NFTA_FWD_SREG_DEV], &priv->sreg_dev, |
| sizeof(int)); |
| } |
| |
| static int nft_fwd_netdev_dump(struct sk_buff *skb, |
| const struct nft_expr *expr, bool reset) |
| { |
| struct nft_fwd_netdev *priv = nft_expr_priv(expr); |
| |
| if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev)) |
| goto nla_put_failure; |
| |
| return 0; |
| |
| nla_put_failure: |
| return -1; |
| } |
| |
| static int nft_fwd_netdev_offload(struct nft_offload_ctx *ctx, |
| struct nft_flow_rule *flow, |
| const struct nft_expr *expr) |
| { |
| const struct nft_fwd_netdev *priv = nft_expr_priv(expr); |
| int oif = ctx->regs[priv->sreg_dev].data.data[0]; |
| |
| return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_REDIRECT, oif); |
| } |
| |
| static bool nft_fwd_netdev_offload_action(const struct nft_expr *expr) |
| { |
| return true; |
| } |
| |
| struct nft_fwd_neigh { |
| u8 sreg_dev; |
| u8 sreg_addr; |
| u8 nfproto; |
| }; |
| |
| static void nft_fwd_neigh_eval(const struct nft_expr *expr, |
| struct nft_regs *regs, |
| const struct nft_pktinfo *pkt) |
| { |
| struct nft_fwd_neigh *priv = nft_expr_priv(expr); |
| void *addr = ®s->data[priv->sreg_addr]; |
| int oif = regs->data[priv->sreg_dev]; |
| unsigned int verdict = NF_STOLEN; |
| struct sk_buff *skb = pkt->skb; |
| struct net_device *dev; |
| int neigh_table; |
| |
| switch (priv->nfproto) { |
| case NFPROTO_IPV4: { |
| struct iphdr *iph; |
| |
| if (skb->protocol != htons(ETH_P_IP)) { |
| verdict = NFT_BREAK; |
| goto out; |
| } |
| if (skb_try_make_writable(skb, sizeof(*iph))) { |
| verdict = NF_DROP; |
| goto out; |
| } |
| iph = ip_hdr(skb); |
| ip_decrease_ttl(iph); |
| neigh_table = NEIGH_ARP_TABLE; |
| break; |
| } |
| case NFPROTO_IPV6: { |
| struct ipv6hdr *ip6h; |
| |
| if (skb->protocol != htons(ETH_P_IPV6)) { |
| verdict = NFT_BREAK; |
| goto out; |
| } |
| if (skb_try_make_writable(skb, sizeof(*ip6h))) { |
| verdict = NF_DROP; |
| goto out; |
| } |
| ip6h = ipv6_hdr(skb); |
| ip6h->hop_limit--; |
| neigh_table = NEIGH_ND_TABLE; |
| break; |
| } |
| default: |
| verdict = NFT_BREAK; |
| goto out; |
| } |
| |
| dev = dev_get_by_index_rcu(nft_net(pkt), oif); |
| if (dev == NULL) |
| return; |
| |
| skb->dev = dev; |
| skb_clear_tstamp(skb); |
| neigh_xmit(neigh_table, dev, addr, skb); |
| out: |
| regs->verdict.code = verdict; |
| } |
| |
| static int nft_fwd_neigh_init(const struct nft_ctx *ctx, |
| const struct nft_expr *expr, |
| const struct nlattr * const tb[]) |
| { |
| struct nft_fwd_neigh *priv = nft_expr_priv(expr); |
| unsigned int addr_len; |
| int err; |
| |
| if (!tb[NFTA_FWD_SREG_DEV] || |
| !tb[NFTA_FWD_SREG_ADDR] || |
| !tb[NFTA_FWD_NFPROTO]) |
| return -EINVAL; |
| |
| priv->nfproto = ntohl(nla_get_be32(tb[NFTA_FWD_NFPROTO])); |
| |
| switch (priv->nfproto) { |
| case NFPROTO_IPV4: |
| addr_len = sizeof(struct in_addr); |
| break; |
| case NFPROTO_IPV6: |
| addr_len = sizeof(struct in6_addr); |
| break; |
| default: |
| return -EOPNOTSUPP; |
| } |
| |
| err = nft_parse_register_load(tb[NFTA_FWD_SREG_DEV], &priv->sreg_dev, |
| sizeof(int)); |
| if (err < 0) |
| return err; |
| |
| return nft_parse_register_load(tb[NFTA_FWD_SREG_ADDR], &priv->sreg_addr, |
| addr_len); |
| } |
| |
| static int nft_fwd_neigh_dump(struct sk_buff *skb, |
| const struct nft_expr *expr, bool reset) |
| { |
| struct nft_fwd_neigh *priv = nft_expr_priv(expr); |
| |
| if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev) || |
| nft_dump_register(skb, NFTA_FWD_SREG_ADDR, priv->sreg_addr) || |
| nla_put_be32(skb, NFTA_FWD_NFPROTO, htonl(priv->nfproto))) |
| goto nla_put_failure; |
| |
| return 0; |
| |
| nla_put_failure: |
| return -1; |
| } |
| |
| static int nft_fwd_validate(const struct nft_ctx *ctx, |
| const struct nft_expr *expr, |
| const struct nft_data **data) |
| { |
| return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS) | |
| (1 << NF_NETDEV_EGRESS)); |
| } |
| |
| static struct nft_expr_type nft_fwd_netdev_type; |
| static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = { |
| .type = &nft_fwd_netdev_type, |
| .size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_neigh)), |
| .eval = nft_fwd_neigh_eval, |
| .init = nft_fwd_neigh_init, |
| .dump = nft_fwd_neigh_dump, |
| .validate = nft_fwd_validate, |
| .reduce = NFT_REDUCE_READONLY, |
| }; |
| |
| static const struct nft_expr_ops nft_fwd_netdev_ops = { |
| .type = &nft_fwd_netdev_type, |
| .size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)), |
| .eval = nft_fwd_netdev_eval, |
| .init = nft_fwd_netdev_init, |
| .dump = nft_fwd_netdev_dump, |
| .validate = nft_fwd_validate, |
| .reduce = NFT_REDUCE_READONLY, |
| .offload = nft_fwd_netdev_offload, |
| .offload_action = nft_fwd_netdev_offload_action, |
| }; |
| |
| static const struct nft_expr_ops * |
| nft_fwd_select_ops(const struct nft_ctx *ctx, |
| const struct nlattr * const tb[]) |
| { |
| if (tb[NFTA_FWD_SREG_ADDR]) |
| return &nft_fwd_neigh_netdev_ops; |
| if (tb[NFTA_FWD_SREG_DEV]) |
| return &nft_fwd_netdev_ops; |
| |
| return ERR_PTR(-EOPNOTSUPP); |
| } |
| |
| static struct nft_expr_type nft_fwd_netdev_type __read_mostly = { |
| .family = NFPROTO_NETDEV, |
| .name = "fwd", |
| .select_ops = nft_fwd_select_ops, |
| .policy = nft_fwd_netdev_policy, |
| .maxattr = NFTA_FWD_MAX, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init nft_fwd_netdev_module_init(void) |
| { |
| return nft_register_expr(&nft_fwd_netdev_type); |
| } |
| |
| static void __exit nft_fwd_netdev_module_exit(void) |
| { |
| nft_unregister_expr(&nft_fwd_netdev_type); |
| } |
| |
| module_init(nft_fwd_netdev_module_init); |
| module_exit(nft_fwd_netdev_module_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); |
| MODULE_DESCRIPTION("nftables netdev packet forwarding support"); |
| MODULE_ALIAS_NFT_AF_EXPR(5, "fwd"); |