1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/netlink.h>
10#include <linux/netfilter.h>
11#include <linux/netfilter/nf_tables.h>
12#include <net/netfilter/nf_tables.h>
13#include <net/netfilter/nf_tables_offload.h>
14#include <net/netfilter/nf_dup_netdev.h>
15
16#define NF_RECURSION_LIMIT 2
17
18static DEFINE_PER_CPU(u8, nf_dup_skb_recursion);
19
20static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev,
21 enum nf_dev_hooks hook)
22{
23 if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT)
24 goto err;
25
26 if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) {
27 if (skb_cow_head(skb, headroom: skb->mac_len))
28 goto err;
29
30 skb_push(skb, len: skb->mac_len);
31 }
32
33 skb->dev = dev;
34 skb_clear_tstamp(skb);
35 __this_cpu_inc(nf_dup_skb_recursion);
36 dev_queue_xmit(skb);
37 __this_cpu_dec(nf_dup_skb_recursion);
38 return;
39err:
40 kfree_skb(skb);
41}
42
43void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif)
44{
45 struct net_device *dev;
46
47 dev = dev_get_by_index_rcu(net: nft_net(pkt), ifindex: oif);
48 if (!dev) {
49 kfree_skb(skb: pkt->skb);
50 return;
51 }
52
53 nf_do_netdev_egress(skb: pkt->skb, dev, hook: nft_hook(pkt));
54}
55EXPORT_SYMBOL_GPL(nf_fwd_netdev_egress);
56
57void nf_dup_netdev_egress(const struct nft_pktinfo *pkt, int oif)
58{
59 struct net_device *dev;
60 struct sk_buff *skb;
61
62 dev = dev_get_by_index_rcu(net: nft_net(pkt), ifindex: oif);
63 if (dev == NULL)
64 return;
65
66 skb = skb_clone(skb: pkt->skb, GFP_ATOMIC);
67 if (skb)
68 nf_do_netdev_egress(skb, dev, hook: nft_hook(pkt));
69}
70EXPORT_SYMBOL_GPL(nf_dup_netdev_egress);
71
72int nft_fwd_dup_netdev_offload(struct nft_offload_ctx *ctx,
73 struct nft_flow_rule *flow,
74 enum flow_action_id id, int oif)
75{
76 struct flow_action_entry *entry;
77 struct net_device *dev;
78
79 /* nft_flow_rule_destroy() releases the reference on this device. */
80 dev = dev_get_by_index(net: ctx->net, ifindex: oif);
81 if (!dev)
82 return -EOPNOTSUPP;
83
84 entry = &flow->rule->action.entries[ctx->num_actions++];
85 entry->id = id;
86 entry->dev = dev;
87
88 return 0;
89}
90EXPORT_SYMBOL_GPL(nft_fwd_dup_netdev_offload);
91
92MODULE_LICENSE("GPL");
93MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
94MODULE_DESCRIPTION("Netfilter packet duplication support");
95

source code of linux/net/netfilter/nf_dup_netdev.c