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Date: Fri, 29 May 2015 01:44:55 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 4/4] netfilter: nf_tables: add netdev table to filter from ingress
This allows us to create netdev tables that contain ingress chains. Use
skb_header_pointer() as we may see shared sk_buffs at this stage.
This change provides access to the existing nf_tables features from the ingress
hook.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netns/nftables.h | 1 +
net/netfilter/Kconfig | 5 ++
net/netfilter/Makefile | 1 +
net/netfilter/nf_tables_netdev.c | 183 ++++++++++++++++++++++++++++++++++++++
4 files changed, 190 insertions(+)
create mode 100644 net/netfilter/nf_tables_netdev.c
diff --git a/include/net/netns/nftables.h b/include/net/netns/nftables.h
index eee608b..c807811 100644
--- a/include/net/netns/nftables.h
+++ b/include/net/netns/nftables.h
@@ -13,6 +13,7 @@ struct netns_nftables {
struct nft_af_info *inet;
struct nft_af_info *arp;
struct nft_af_info *bridge;
+ struct nft_af_info *netdev;
unsigned int base_seq;
u8 gencursor;
};
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 9a89e7c..bd5aaeb 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -456,6 +456,11 @@ config NF_TABLES_INET
help
This option enables support for a mixed IPv4/IPv6 "inet" table.
+config NF_TABLES_NETDEV
+ tristate "Netfilter nf_tables netdev tables support"
+ help
+ This option enables support for the "netdev" table.
+
config NFT_EXTHDR
tristate "Netfilter nf_tables IPv6 exthdr module"
help
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index a87d8b8..70d026d 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -75,6 +75,7 @@ nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
obj-$(CONFIG_NF_TABLES) += nf_tables.o
obj-$(CONFIG_NF_TABLES_INET) += nf_tables_inet.o
+obj-$(CONFIG_NF_TABLES_NETDEV) += nf_tables_netdev.o
obj-$(CONFIG_NFT_COMPAT) += nft_compat.o
obj-$(CONFIG_NFT_EXTHDR) += nft_exthdr.o
obj-$(CONFIG_NFT_META) += nft_meta.o
diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c
new file mode 100644
index 0000000..04cb170
--- /dev/null
+++ b/net/netfilter/nf_tables_netdev.c
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2015 Pablo Neira Ayuso <pablo@...filter.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 <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 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);
+
+ return ret;
+}
+
+static void __exit nf_tables_netdev_exit(void)
+{
+ 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@...filter.org>");
+MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */
--
1.7.10.4
--
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