diff options
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/netfilter/Kconfig | 10 | ||||
| -rw-r--r-- | net/ipv6/netfilter/Makefile | 1 | ||||
| -rw-r--r-- | net/ipv6/netfilter/ip6t_rpfilter.c | 133 | ||||
| -rw-r--r-- | net/ipv6/route.c | 7 |
4 files changed, 151 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig index f792b34cbe9c..9a68fb5b9e77 100644 --- a/net/ipv6/netfilter/Kconfig +++ b/net/ipv6/netfilter/Kconfig @@ -125,6 +125,16 @@ config IP6_NF_MATCH_MH To compile it as a module, choose M here. If unsure, say N. +config IP6_NF_MATCH_RPFILTER + tristate '"rpfilter" reverse path filter match support' + depends on NETFILTER_ADVANCED + ---help--- + This option allows you to match packets whose replies would + go out via the interface the packet came in. + + To compile it as a module, choose M here. If unsure, say N. + The module will be called ip6t_rpfilter. + config IP6_NF_MATCH_RT tristate '"rt" Routing header match support' depends on NETFILTER_ADVANCED diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile index abfee91ce816..2eaed96db02c 100644 --- a/net/ipv6/netfilter/Makefile +++ b/net/ipv6/netfilter/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_IP6_NF_MATCH_FRAG) += ip6t_frag.o obj-$(CONFIG_IP6_NF_MATCH_IPV6HEADER) += ip6t_ipv6header.o obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o +obj-$(CONFIG_IP6_NF_MATCH_RPFILTER) += ip6t_rpfilter.o obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o # targets diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c new file mode 100644 index 000000000000..5d1d8b04d694 --- /dev/null +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -0,0 +1,133 @@ +/* + * Copyright (c) 2011 Florian Westphal <fw@strlen.de> + * + * 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. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/route.h> +#include <net/ip6_fib.h> +#include <net/ip6_route.h> + +#include <linux/netfilter/xt_rpfilter.h> +#include <linux/netfilter/x_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); +MODULE_DESCRIPTION("Xtables: IPv6 reverse path filter match"); + +static bool rpfilter_addr_unicast(const struct in6_addr *addr) +{ + int addr_type = ipv6_addr_type(addr); + return addr_type & IPV6_ADDR_UNICAST; +} + +static bool rpfilter_lookup_reverse6(const struct sk_buff *skb, + const struct net_device *dev, u8 flags) +{ + struct rt6_info *rt; + struct ipv6hdr *iph = ipv6_hdr(skb); + bool ret = false; + struct flowi6 fl6 = { + .flowlabel = (* (__be32 *) iph) & IPV6_FLOWINFO_MASK, + .flowi6_proto = iph->nexthdr, + .daddr = iph->saddr, + }; + int lookup_flags; + + if (rpfilter_addr_unicast(&iph->daddr)) { + memcpy(&fl6.saddr, &iph->daddr, sizeof(struct in6_addr)); + lookup_flags = RT6_LOOKUP_F_HAS_SADDR; + } else { + lookup_flags = 0; + } + + fl6.flowi6_mark = flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0; + if ((flags & XT_RPFILTER_LOOSE) == 0) { + fl6.flowi6_oif = dev->ifindex; + lookup_flags |= RT6_LOOKUP_F_IFACE; + } + + rt = (void *) ip6_route_lookup(dev_net(dev), &fl6, lookup_flags); + if (rt->dst.error) + goto out; + + if (rt->rt6i_flags & (RTF_REJECT|RTF_ANYCAST)) + goto out; + + if (rt->rt6i_flags & RTF_LOCAL) { + ret = flags & XT_RPFILTER_ACCEPT_LOCAL; + goto out; + } + + if (rt->rt6i_idev->dev == dev || (flags & XT_RPFILTER_LOOSE)) + ret = true; + out: + dst_release(&rt->dst); + return ret; +} + +static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_rpfilter_info *info = par->matchinfo; + int saddrtype; + struct ipv6hdr *iph; + bool invert = info->flags & XT_RPFILTER_INVERT; + + if (par->in->flags & IFF_LOOPBACK) + return true ^ invert; + + iph = ipv6_hdr(skb); + saddrtype = ipv6_addr_type(&iph->saddr); + if (unlikely(saddrtype == IPV6_ADDR_ANY)) + return true ^ invert; /* not routable: forward path will drop it */ + + return rpfilter_lookup_reverse6(skb, par->in, info->flags) ^ invert; +} + +static int rpfilter_check(const struct xt_mtchk_param *par) +{ + const struct xt_rpfilter_info *info = par->matchinfo; + unsigned int options = ~XT_RPFILTER_OPTION_MASK; + + if (info->flags & options) { + pr_info("unknown options encountered"); + return -EINVAL; + } + + if (strcmp(par->table, "mangle") != 0 && + strcmp(par->table, "raw") != 0) { + pr_info("match only valid in the \'raw\' " + "or \'mangle\' tables, not \'%s\'.\n", par->table); + return -EINVAL; + } + + return 0; +} + +static struct xt_match rpfilter_mt_reg __read_mostly = { + .name = "rpfilter", + .family = NFPROTO_IPV6, + .checkentry = rpfilter_check, + .match = rpfilter_mt, + .matchsize = sizeof(struct xt_rpfilter_info), + .hooks = (1 << NF_INET_PRE_ROUTING), + .me = THIS_MODULE +}; + +static int __init rpfilter_mt_init(void) +{ + return xt_register_match(&rpfilter_mt_reg); +} + +static void __exit rpfilter_mt_exit(void) +{ + xt_unregister_match(&rpfilter_mt_reg); +} + +module_init(rpfilter_mt_init); +module_exit(rpfilter_mt_exit); diff --git a/net/ipv6/route.c b/net/ipv6/route.c index ad438546d915..5855e9ede3cb 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -658,6 +658,13 @@ out: } +struct dst_entry * ip6_route_lookup(struct net *net, struct flowi6 *fl6, + int flags) +{ + return fib6_rule_lookup(net, fl6, flags, ip6_pol_route_lookup); +} +EXPORT_SYMBOL_GPL(ip6_route_lookup); + struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr, const struct in6_addr *saddr, int oif, int strict) { |
