diff options
Diffstat (limited to 'net/netfilter/nf_tables_netdev.c')
| -rw-r--r-- | net/netfilter/nf_tables_netdev.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c new file mode 100644 index 000000000000..2cae4d4a03b7 --- /dev/null +++ b/net/netfilter/nf_tables_netdev.c @@ -0,0 +1,258 @@ +/* + * 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, + const struct nf_hook_ops *ops, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct iphdr *iph, _iph; + u32 len, thoff; + + nft_set_pktinfo(pkt, ops, 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, + const struct nf_hook_ops *ops, + 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, + const struct nf_hook_ops *ops, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + nft_set_pktinfo(pkt, ops, skb, state); + __nft_netdev_set_pktinfo_ipv6(pkt, ops, skb, state); +} + +static unsigned int +nft_do_chain_netdev(const struct nf_hook_ops *ops, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct nft_pktinfo pkt; + + switch (eth_hdr(skb)->h_proto) { + case htons(ETH_P_IP): + nft_netdev_set_pktinfo_ipv4(&pkt, ops, skb, state); + break; + case htons(ETH_P_IPV6): + nft_netdev_set_pktinfo_ipv6(&pkt, ops, skb, state); + break; + default: + nft_set_pktinfo(&pkt, ops, skb, state); + break; + } + + return nft_do_chain(&pkt, ops); +} + +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 */ |