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![Florian Westphal](/assets/img/avatar_default.png)
Now that the egress function can be called from egress hook, we need
to avoid recursive calls into the nf_tables traverser, else crash.
Fixes: f87b9464d1
("netfilter: nft_fwd_netdev: Support egress hook")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
// 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 <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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#define NF_RECURSION_LIMIT 2
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static DEFINE_PER_CPU(u8, nf_dup_skb_recursion);
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static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev,
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enum nf_dev_hooks hook)
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{
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if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT)
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goto err;
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if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) {
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if (skb_cow_head(skb, skb->mac_len))
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goto err;
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skb_push(skb, skb->mac_len);
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}
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skb->dev = dev;
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skb_clear_tstamp(skb);
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__this_cpu_inc(nf_dup_skb_recursion);
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dev_queue_xmit(skb);
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__this_cpu_dec(nf_dup_skb_recursion);
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return;
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err:
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kfree_skb(skb);
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}
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void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif)
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{
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struct net_device *dev;
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dev = dev_get_by_index_rcu(nft_net(pkt), oif);
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if (!dev) {
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kfree_skb(pkt->skb);
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return;
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}
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nf_do_netdev_egress(pkt->skb, dev, nft_hook(pkt));
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}
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EXPORT_SYMBOL_GPL(nf_fwd_netdev_egress);
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void nf_dup_netdev_egress(const struct nft_pktinfo *pkt, int oif)
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{
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struct net_device *dev;
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struct sk_buff *skb;
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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 = skb_clone(pkt->skb, GFP_ATOMIC);
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if (skb)
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nf_do_netdev_egress(skb, dev, nft_hook(pkt));
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}
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EXPORT_SYMBOL_GPL(nf_dup_netdev_egress);
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int nft_fwd_dup_netdev_offload(struct nft_offload_ctx *ctx,
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struct nft_flow_rule *flow,
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enum flow_action_id id, int oif)
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{
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struct flow_action_entry *entry;
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struct net_device *dev;
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/* nft_flow_rule_destroy() releases the reference on this device. */
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dev = dev_get_by_index(ctx->net, oif);
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if (!dev)
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return -EOPNOTSUPP;
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entry = &flow->rule->action.entries[ctx->num_actions++];
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entry->id = id;
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entry->dev = dev;
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return 0;
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}
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EXPORT_SYMBOL_GPL(nft_fwd_dup_netdev_offload);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
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MODULE_DESCRIPTION("Netfilter packet duplication support");
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