diff --git a/include/net/netfilter/ipv4/nf_nat_masquerade.h b/include/net/netfilter/ipv4/nf_nat_masquerade.h new file mode 100644 index 000000000000..a9c001c646da --- /dev/null +++ b/include/net/netfilter/ipv4/nf_nat_masquerade.h @@ -0,0 +1,14 @@ +#ifndef _NF_NAT_MASQUERADE_IPV4_H_ +#define _NF_NAT_MASQUERADE_IPV4_H_ + +#include + +unsigned int +nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum, + const struct nf_nat_range *range, + const struct net_device *out); + +void nf_nat_masquerade_ipv4_register_notifier(void); +void nf_nat_masquerade_ipv4_unregister_notifier(void); + +#endif /*_NF_NAT_MASQUERADE_IPV4_H_ */ diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index fb173126f03d..4be3e541350e 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -184,8 +184,15 @@ config NF_NAT_IPV4 if NF_NAT_IPV4 +config NF_NAT_MASQUERADE_IPV4 + tristate "IPv4 masquerade support" + help + This is the kernel functionality to provide NAT in the masquerade + flavour (automatic source address selection). + config IP_NF_TARGET_MASQUERADE tristate "MASQUERADE target support" + select NF_NAT_MASQUERADE_IPV4 default m if NETFILTER_ADVANCED=n help Masquerading is a special case of NAT: all outgoing connections are diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile index 33001621465b..42056b2fd0e3 100644 --- a/net/ipv4/netfilter/Makefile +++ b/net/ipv4/netfilter/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o +obj-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o # NAT protocols (nf_nat) obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c index 00352ce0f0de..da7f02a0b868 100644 --- a/net/ipv4/netfilter/ipt_MASQUERADE.c +++ b/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -22,6 +22,7 @@ #include #include #include +#include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Netfilter Core Team "); @@ -46,103 +47,17 @@ static int masquerade_tg_check(const struct xt_tgchk_param *par) static unsigned int masquerade_tg(struct sk_buff *skb, const struct xt_action_param *par) { - struct nf_conn *ct; - struct nf_conn_nat *nat; - enum ip_conntrack_info ctinfo; - struct nf_nat_range newrange; + struct nf_nat_range range; const struct nf_nat_ipv4_multi_range_compat *mr; - const struct rtable *rt; - __be32 newsrc, nh; - - NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING); - - ct = nf_ct_get(skb, &ctinfo); - nat = nfct_nat(ct); - - NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || - ctinfo == IP_CT_RELATED_REPLY)); - - /* Source address is 0.0.0.0 - locally generated packet that is - * probably not supposed to be masqueraded. - */ - if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0) - return NF_ACCEPT; mr = par->targinfo; - rt = skb_rtable(skb); - nh = rt_nexthop(rt, ip_hdr(skb)->daddr); - newsrc = inet_select_addr(par->out, nh, RT_SCOPE_UNIVERSE); - if (!newsrc) { - pr_info("%s ate my IP address\n", par->out->name); - return NF_DROP; - } + range.flags = mr->range[0].flags; + range.min_proto = mr->range[0].min; + range.max_proto = mr->range[0].max; - nat->masq_index = par->out->ifindex; - - /* Transfer from original range. */ - memset(&newrange.min_addr, 0, sizeof(newrange.min_addr)); - memset(&newrange.max_addr, 0, sizeof(newrange.max_addr)); - newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS; - newrange.min_addr.ip = newsrc; - newrange.max_addr.ip = newsrc; - newrange.min_proto = mr->range[0].min; - newrange.max_proto = mr->range[0].max; - - /* Hand modified range to generic setup. */ - return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC); + return nf_nat_masquerade_ipv4(skb, par->hooknum, &range, par->out); } -static int -device_cmp(struct nf_conn *i, void *ifindex) -{ - const struct nf_conn_nat *nat = nfct_nat(i); - - if (!nat) - return 0; - if (nf_ct_l3num(i) != NFPROTO_IPV4) - 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) { - /* Device was downed. Search entire table for - conntracks which were associated with that device, - and forget them. */ - NF_CT_ASSERT(dev->ifindex != 0); - - nf_ct_iterate_cleanup(net, device_cmp, - (void *)(long)dev->ifindex, 0, 0); - } - - return NOTIFY_DONE; -} - -static int masq_inet_event(struct notifier_block *this, - unsigned long event, - void *ptr) -{ - struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; - struct netdev_notifier_info info; - - netdev_notifier_info_init(&info, dev); - return masq_device_event(this, event, &info); -} - -static struct notifier_block masq_dev_notifier = { - .notifier_call = masq_device_event, -}; - -static struct notifier_block masq_inet_notifier = { - .notifier_call = masq_inet_event, -}; - static struct xt_target masquerade_tg_reg __read_mostly = { .name = "MASQUERADE", .family = NFPROTO_IPV4, @@ -160,12 +75,8 @@ static int __init masquerade_tg_init(void) ret = xt_register_target(&masquerade_tg_reg); - if (ret == 0) { - /* Register for device down reports */ - register_netdevice_notifier(&masq_dev_notifier); - /* Register IP address change reports */ - register_inetaddr_notifier(&masq_inet_notifier); - } + if (ret == 0) + nf_nat_masquerade_ipv4_register_notifier(); return ret; } @@ -173,8 +84,7 @@ static int __init masquerade_tg_init(void) static void __exit masquerade_tg_exit(void) { xt_unregister_target(&masquerade_tg_reg); - unregister_netdevice_notifier(&masq_dev_notifier); - unregister_inetaddr_notifier(&masq_inet_notifier); + nf_nat_masquerade_ipv4_unregister_notifier(); } module_init(masquerade_tg_init); diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c new file mode 100644 index 000000000000..c6eb42100e9a --- /dev/null +++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c @@ -0,0 +1,153 @@ +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 Netfilter Core Team + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +unsigned int +nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum, + const struct nf_nat_range *range, + const struct net_device *out) +{ + struct nf_conn *ct; + struct nf_conn_nat *nat; + enum ip_conntrack_info ctinfo; + struct nf_nat_range newrange; + const struct rtable *rt; + __be32 newsrc, nh; + + NF_CT_ASSERT(hooknum == NF_INET_POST_ROUTING); + + ct = nf_ct_get(skb, &ctinfo); + nat = nfct_nat(ct); + + NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || + ctinfo == IP_CT_RELATED_REPLY)); + + /* Source address is 0.0.0.0 - locally generated packet that is + * probably not supposed to be masqueraded. + */ + if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0) + return NF_ACCEPT; + + rt = skb_rtable(skb); + nh = rt_nexthop(rt, ip_hdr(skb)->daddr); + newsrc = inet_select_addr(out, nh, RT_SCOPE_UNIVERSE); + if (!newsrc) { + pr_info("%s ate my IP address\n", out->name); + return NF_DROP; + } + + nat->masq_index = out->ifindex; + + /* Transfer from original range. */ + memset(&newrange.min_addr, 0, sizeof(newrange.min_addr)); + memset(&newrange.max_addr, 0, sizeof(newrange.max_addr)); + newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; + newrange.min_addr.ip = newsrc; + newrange.max_addr.ip = newsrc; + newrange.min_proto = range->min_proto; + newrange.max_proto = range->max_proto; + + /* Hand modified range to generic setup. */ + return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4); + +static int device_cmp(struct nf_conn *i, void *ifindex) +{ + const struct nf_conn_nat *nat = nfct_nat(i); + + if (!nat) + return 0; + if (nf_ct_l3num(i) != NFPROTO_IPV4) + 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) { + /* Device was downed. Search entire table for + * conntracks which were associated with that device, + * and forget them. + */ + NF_CT_ASSERT(dev->ifindex != 0); + + nf_ct_iterate_cleanup(net, device_cmp, + (void *)(long)dev->ifindex, 0, 0); + } + + return NOTIFY_DONE; +} + +static int masq_inet_event(struct notifier_block *this, + unsigned long event, + void *ptr) +{ + struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; + struct netdev_notifier_info info; + + netdev_notifier_info_init(&info, dev); + return masq_device_event(this, event, &info); +} + +static struct notifier_block masq_dev_notifier = { + .notifier_call = masq_device_event, +}; + +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_ipv4_register_notifier(void) +{ + /* check if the notifier was already set */ + if (atomic_inc_return(&masquerade_notifier_refcount) > 1) + return; + + /* Register for device down reports */ + register_netdevice_notifier(&masq_dev_notifier); + /* Register IP address change reports */ + register_inetaddr_notifier(&masq_inet_notifier); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_register_notifier); + +void nf_nat_masquerade_ipv4_unregister_notifier(void) +{ + /* check if the notifier still has clients */ + if (atomic_dec_return(&masquerade_notifier_refcount) > 0) + return; + + unregister_netdevice_notifier(&masq_dev_notifier); + unregister_inetaddr_notifier(&masq_inet_notifier); +} +EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Rusty Russell ");