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
18 static DEFINE_PER_CPU(u8, nf_dup_skb_recursion);
19
nf_do_netdev_egress(struct sk_buff * skb,struct net_device * dev,enum nf_dev_hooks hook)20 static 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, skb->mac_len))
28 goto err;
29
30 skb_push(skb, 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;
39 err:
40 kfree_skb(skb);
41 }
42
nf_fwd_netdev_egress(const struct nft_pktinfo * pkt,int oif)43 void 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(nft_net(pkt), oif);
48 if (!dev) {
49 kfree_skb(pkt->skb);
50 return;
51 }
52
53 nf_do_netdev_egress(pkt->skb, dev, nft_hook(pkt));
54 }
55 EXPORT_SYMBOL_GPL(nf_fwd_netdev_egress);
56
nf_dup_netdev_egress(const struct nft_pktinfo * pkt,int oif)57 void 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(nft_net(pkt), oif);
63 if (dev == NULL)
64 return;
65
66 skb = skb_clone(pkt->skb, GFP_ATOMIC);
67 if (skb)
68 nf_do_netdev_egress(skb, dev, nft_hook(pkt));
69 }
70 EXPORT_SYMBOL_GPL(nf_dup_netdev_egress);
71
nft_fwd_dup_netdev_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,enum flow_action_id id,int oif)72 int 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(ctx->net, 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 }
90 EXPORT_SYMBOL_GPL(nft_fwd_dup_netdev_offload);
91
92 MODULE_LICENSE("GPL");
93 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
94 MODULE_DESCRIPTION("Netfilter packet duplication support");
95