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- /*
- * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #include <linux/init.h>
- #include <linux/module.h>
- #include <linux/netdevice.h>
- #include <net/netfilter/nf_tables.h>
- #include <linux/ip.h>
- #include <linux/ipv6.h>
- #include <net/netfilter/nf_tables_ipv4.h>
- #include <net/netfilter/nf_tables_ipv6.h>
- static inline void
- nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- struct iphdr *iph, _iph;
- u32 len, thoff;
- nft_set_pktinfo(pkt, skb, state);
- iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
- &_iph);
- if (!iph)
- return;
- iph = ip_hdr(skb);
- if (iph->ihl < 5 || iph->version != 4)
- return;
- len = ntohs(iph->tot_len);
- thoff = iph->ihl * 4;
- if (skb->len < len)
- return;
- else if (len < thoff)
- return;
- pkt->tprot = iph->protocol;
- pkt->xt.thoff = thoff;
- pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
- }
- static inline void
- __nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- #if IS_ENABLED(CONFIG_IPV6)
- struct ipv6hdr *ip6h, _ip6h;
- unsigned int thoff = 0;
- unsigned short frag_off;
- int protohdr;
- u32 pkt_len;
- ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
- &_ip6h);
- if (!ip6h)
- return;
- if (ip6h->version != 6)
- return;
- pkt_len = ntohs(ip6h->payload_len);
- if (pkt_len + sizeof(*ip6h) > skb->len)
- return;
- protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
- if (protohdr < 0)
- return;
- pkt->tprot = protohdr;
- pkt->xt.thoff = thoff;
- pkt->xt.fragoff = frag_off;
- #endif
- }
- static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- nft_set_pktinfo(pkt, skb, state);
- __nft_netdev_set_pktinfo_ipv6(pkt, skb, state);
- }
- static unsigned int
- nft_do_chain_netdev(void *priv, struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- struct nft_pktinfo pkt;
- switch (skb->protocol) {
- case htons(ETH_P_IP):
- nft_netdev_set_pktinfo_ipv4(&pkt, skb, state);
- break;
- case htons(ETH_P_IPV6):
- nft_netdev_set_pktinfo_ipv6(&pkt, skb, state);
- break;
- default:
- nft_set_pktinfo(&pkt, skb, state);
- break;
- }
- return nft_do_chain(&pkt, priv);
- }
- static struct nft_af_info nft_af_netdev __read_mostly = {
- .family = NFPROTO_NETDEV,
- .nhooks = NF_NETDEV_NUMHOOKS,
- .owner = THIS_MODULE,
- .flags = NFT_AF_NEEDS_DEV,
- .nops = 1,
- .hooks = {
- [NF_NETDEV_INGRESS] = nft_do_chain_netdev,
- },
- };
- static int nf_tables_netdev_init_net(struct net *net)
- {
- net->nft.netdev = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
- if (net->nft.netdev == NULL)
- return -ENOMEM;
- memcpy(net->nft.netdev, &nft_af_netdev, sizeof(nft_af_netdev));
- if (nft_register_afinfo(net, net->nft.netdev) < 0)
- goto err;
- return 0;
- err:
- kfree(net->nft.netdev);
- return -ENOMEM;
- }
- static void nf_tables_netdev_exit_net(struct net *net)
- {
- nft_unregister_afinfo(net->nft.netdev);
- kfree(net->nft.netdev);
- }
- static struct pernet_operations nf_tables_netdev_net_ops = {
- .init = nf_tables_netdev_init_net,
- .exit = nf_tables_netdev_exit_net,
- };
- static const struct nf_chain_type nft_filter_chain_netdev = {
- .name = "filter",
- .type = NFT_CHAIN_T_DEFAULT,
- .family = NFPROTO_NETDEV,
- .owner = THIS_MODULE,
- .hook_mask = (1 << NF_NETDEV_INGRESS),
- };
- static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
- struct net_device *dev, struct nft_table *table,
- struct nft_base_chain *basechain)
- {
- switch (event) {
- case NETDEV_REGISTER:
- if (strcmp(basechain->dev_name, dev->name) != 0)
- return;
- BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));
- dev_hold(dev);
- basechain->ops[0].dev = dev;
- basechain->flags &= ~NFT_BASECHAIN_DISABLED;
- if (!(table->flags & NFT_TABLE_F_DORMANT))
- nft_register_basechain(basechain, afi->nops);
- break;
- case NETDEV_UNREGISTER:
- if (strcmp(basechain->dev_name, dev->name) != 0)
- return;
- BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);
- if (!(table->flags & NFT_TABLE_F_DORMANT))
- nft_unregister_basechain(basechain, afi->nops);
- dev_put(basechain->ops[0].dev);
- basechain->ops[0].dev = NULL;
- basechain->flags |= NFT_BASECHAIN_DISABLED;
- break;
- case NETDEV_CHANGENAME:
- if (dev->ifindex != basechain->ops[0].dev->ifindex)
- return;
- strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
- break;
- }
- }
- static int nf_tables_netdev_event(struct notifier_block *this,
- unsigned long event, void *ptr)
- {
- struct net_device *dev = netdev_notifier_info_to_dev(ptr);
- struct nft_af_info *afi;
- struct nft_table *table;
- struct nft_chain *chain;
- nfnl_lock(NFNL_SUBSYS_NFTABLES);
- list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
- if (afi->family != NFPROTO_NETDEV)
- continue;
- list_for_each_entry(table, &afi->tables, list) {
- list_for_each_entry(chain, &table->chains, list) {
- if (!(chain->flags & NFT_BASE_CHAIN))
- continue;
- nft_netdev_event(event, afi, dev, table,
- nft_base_chain(chain));
- }
- }
- }
- nfnl_unlock(NFNL_SUBSYS_NFTABLES);
- return NOTIFY_DONE;
- }
- static struct notifier_block nf_tables_netdev_notifier = {
- .notifier_call = nf_tables_netdev_event,
- };
- static int __init nf_tables_netdev_init(void)
- {
- int ret;
- nft_register_chain_type(&nft_filter_chain_netdev);
- ret = register_pernet_subsys(&nf_tables_netdev_net_ops);
- if (ret < 0)
- nft_unregister_chain_type(&nft_filter_chain_netdev);
- register_netdevice_notifier(&nf_tables_netdev_notifier);
- return ret;
- }
- static void __exit nf_tables_netdev_exit(void)
- {
- unregister_netdevice_notifier(&nf_tables_netdev_notifier);
- unregister_pernet_subsys(&nf_tables_netdev_net_ops);
- nft_unregister_chain_type(&nft_filter_chain_netdev);
- }
- module_init(nf_tables_netdev_init);
- module_exit(nf_tables_netdev_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
- MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */
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