From be6b635cd674add9410efa9ac6f03e0040848b12 Mon Sep 17 00:00:00 2001 From: Arturo Borrero Date: Thu, 4 Sep 2014 14:06:49 +0200 Subject: [PATCH] netfilter: nf_nat: generalize IPv6 masquerading support for nf_tables Let's refactor the code so we can reach the masquerade functionality from outside the xt context (ie. nftables). The patch includes the addition of an atomic counter to the masquerade notifier: the stuff to be done by the notifier is the same for xt and nftables. Therefore, only one notification handler is needed. This factorization only involves IPv6; a similar patch exists to handle IPv4. Signed-off-by: Arturo Borrero Gonzalez Signed-off-by: Pablo Neira Ayuso --- .../net/netfilter/ipv6/nf_nat_masquerade.h | 10 ++ net/ipv6/netfilter/Kconfig | 7 + net/ipv6/netfilter/Makefile | 1 + net/ipv6/netfilter/ip6t_MASQUERADE.c | 76 +---------- net/ipv6/netfilter/nf_nat_masquerade_ipv6.c | 120 ++++++++++++++++++ 5 files changed, 143 insertions(+), 71 deletions(-) create mode 100644 include/net/netfilter/ipv6/nf_nat_masquerade.h create mode 100644 net/ipv6/netfilter/nf_nat_masquerade_ipv6.c diff --git a/include/net/netfilter/ipv6/nf_nat_masquerade.h b/include/net/netfilter/ipv6/nf_nat_masquerade.h new file mode 100644 index 000000000000..0a13396cd390 --- /dev/null +++ b/include/net/netfilter/ipv6/nf_nat_masquerade.h @@ -0,0 +1,10 @@ +#ifndef _NF_NAT_MASQUERADE_IPV6_H_ +#define _NF_NAT_MASQUERADE_IPV6_H_ + +unsigned int +nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range *range, + const struct net_device *out); +void nf_nat_masquerade_ipv6_register_notifier(void); +void nf_nat_masquerade_ipv6_unregister_notifier(void); + +#endif /* _NF_NAT_MASQUERADE_IPV6_H_ */ diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig index ac93df16f5af..6c8cfec6836a 100644 --- a/net/ipv6/netfilter/Kconfig +++ b/net/ipv6/netfilter/Kconfig @@ -246,8 +246,15 @@ config NF_NAT_IPV6 if NF_NAT_IPV6 +config NF_NAT_MASQUERADE_IPV6 + tristate "IPv6 masquerade support" + help + This is the kernel functionality to provide NAT in the masquerade + flavour (automatic source address selection) for IPv6. + config IP6_NF_TARGET_MASQUERADE tristate "MASQUERADE target support" + select NF_NAT_MASQUERADE_IPV6 help Masquerading is a special case of NAT: all outgoing connections are changed to seem to come from a particular interface's address, and diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile index c0b263104ed2..89a0bd751f82 100644 --- a/net/ipv6/netfilter/Makefile +++ b/net/ipv6/netfilter/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_NF_CONNTRACK_IPV6) += nf_conntrack_ipv6.o nf_nat_ipv6-y := nf_nat_l3proto_ipv6.o nf_nat_proto_icmpv6.o obj-$(CONFIG_NF_NAT_IPV6) += nf_nat_ipv6.o +obj-$(CONFIG_NF_NAT_MASQUERADE_IPV6) += nf_nat_masquerade_ipv6.o # defrag nf_defrag_ipv6-y := nf_defrag_ipv6_hooks.o nf_conntrack_reasm.o diff --git a/net/ipv6/netfilter/ip6t_MASQUERADE.c b/net/ipv6/netfilter/ip6t_MASQUERADE.c index 3e4e92d5e157..7f9f45d829d2 100644 --- a/net/ipv6/netfilter/ip6t_MASQUERADE.c +++ b/net/ipv6/netfilter/ip6t_MASQUERADE.c @@ -19,33 +19,12 @@ #include #include #include +#include static unsigned int masquerade_tg6(struct sk_buff *skb, const struct xt_action_param *par) { - const struct nf_nat_range *range = par->targinfo; - enum ip_conntrack_info ctinfo; - struct in6_addr src; - struct nf_conn *ct; - struct nf_nat_range newrange; - - ct = nf_ct_get(skb, &ctinfo); - NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || - ctinfo == IP_CT_RELATED_REPLY)); - - if (ipv6_dev_get_saddr(dev_net(par->out), par->out, - &ipv6_hdr(skb)->daddr, 0, &src) < 0) - return NF_DROP; - - nfct_nat(ct)->masq_index = par->out->ifindex; - - newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; - newrange.min_addr.in6 = src; - newrange.max_addr.in6 = src; - newrange.min_proto = range->min_proto; - newrange.max_proto = range->max_proto; - - return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC); + return nf_nat_masquerade_ipv6(skb, par->targinfo, par->out); } static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par) @@ -57,48 +36,6 @@ static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par) return 0; } -static int device_cmp(struct nf_conn *ct, void *ifindex) -{ - const struct nf_conn_nat *nat = nfct_nat(ct); - - if (!nat) - return 0; - if (nf_ct_l3num(ct) != NFPROTO_IPV6) - return 0; - return nat->masq_index == (int)(long)ifindex; -} - -static int masq_device_event(struct notifier_block *this, - unsigned long event, void *ptr) -{ - const struct net_device *dev = netdev_notifier_info_to_dev(ptr); - struct net *net = dev_net(dev); - - if (event == NETDEV_DOWN) - nf_ct_iterate_cleanup(net, device_cmp, - (void *)(long)dev->ifindex, 0, 0); - - return NOTIFY_DONE; -} - -static struct notifier_block masq_dev_notifier = { - .notifier_call = masq_device_event, -}; - -static int masq_inet_event(struct notifier_block *this, - unsigned long event, void *ptr) -{ - struct inet6_ifaddr *ifa = ptr; - struct netdev_notifier_info info; - - netdev_notifier_info_init(&info, ifa->idev->dev); - return masq_device_event(this, event, &info); -} - -static struct notifier_block masq_inet_notifier = { - .notifier_call = masq_inet_event, -}; - static struct xt_target masquerade_tg6_reg __read_mostly = { .name = "MASQUERADE", .family = NFPROTO_IPV6, @@ -115,17 +52,14 @@ static int __init masquerade_tg6_init(void) int err; err = xt_register_target(&masquerade_tg6_reg); - if (err == 0) { - register_netdevice_notifier(&masq_dev_notifier); - register_inet6addr_notifier(&masq_inet_notifier); - } + if (err == 0) + nf_nat_masquerade_ipv6_register_notifier(); return err; } static void __exit masquerade_tg6_exit(void) { - unregister_inet6addr_notifier(&masq_inet_notifier); - unregister_netdevice_notifier(&masq_dev_notifier); + nf_nat_masquerade_ipv6_unregister_notifier(); xt_unregister_target(&masquerade_tg6_reg); } diff --git a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c new file mode 100644 index 000000000000..7745609665cd --- /dev/null +++ b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c @@ -0,0 +1,120 @@ +/* + * Copyright (c) 2011 Patrick McHardy + * + * 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. + * + * Based on Rusty Russell's IPv6 MASQUERADE target. Development of IPv6 + * NAT funded by Astaro. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +unsigned int +nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range *range, + const struct net_device *out) +{ + enum ip_conntrack_info ctinfo; + struct in6_addr src; + struct nf_conn *ct; + struct nf_nat_range newrange; + + ct = nf_ct_get(skb, &ctinfo); + NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || + ctinfo == IP_CT_RELATED_REPLY)); + + if (ipv6_dev_get_saddr(dev_net(out), out, + &ipv6_hdr(skb)->daddr, 0, &src) < 0) + return NF_DROP; + + nfct_nat(ct)->masq_index = out->ifindex; + + newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; + newrange.min_addr.in6 = src; + newrange.max_addr.in6 = src; + newrange.min_proto = range->min_proto; + newrange.max_proto = range->max_proto; + + return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6); + +static int device_cmp(struct nf_conn *ct, void *ifindex) +{ + const struct nf_conn_nat *nat = nfct_nat(ct); + + if (!nat) + return 0; + if (nf_ct_l3num(ct) != NFPROTO_IPV6) + return 0; + return nat->masq_index == (int)(long)ifindex; +} + +static int masq_device_event(struct notifier_block *this, + unsigned long event, void *ptr) +{ + const struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct net *net = dev_net(dev); + + if (event == NETDEV_DOWN) + nf_ct_iterate_cleanup(net, device_cmp, + (void *)(long)dev->ifindex, 0, 0); + + return NOTIFY_DONE; +} + +static struct notifier_block masq_dev_notifier = { + .notifier_call = masq_device_event, +}; + +static int masq_inet_event(struct notifier_block *this, + unsigned long event, void *ptr) +{ + struct inet6_ifaddr *ifa = ptr; + struct netdev_notifier_info info; + + netdev_notifier_info_init(&info, ifa->idev->dev); + return masq_device_event(this, event, &info); +} + +static struct notifier_block masq_inet_notifier = { + .notifier_call = masq_inet_event, +}; + +static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0); + +void nf_nat_masquerade_ipv6_register_notifier(void) +{ + /* check if the notifier is already set */ + if (atomic_inc_return(&masquerade_notifier_refcount) > 1) + return; + + register_netdevice_notifier(&masq_dev_notifier); + register_inet6addr_notifier(&masq_inet_notifier); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier); + +void nf_nat_masquerade_ipv6_unregister_notifier(void) +{ + /* check if the notifier still has clients */ + if (atomic_dec_return(&masquerade_notifier_refcount) > 0) + return; + + unregister_inet6addr_notifier(&masq_inet_notifier); + unregister_netdevice_notifier(&masq_dev_notifier); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Patrick McHardy "); -- 2.30.2