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@@ -0,0 +1,287 @@
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+/*
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+ * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ *
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+ * Development of IPv6 NAT funded by Astaro.
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+ */
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+#include <linux/types.h>
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+#include <linux/module.h>
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+#include <linux/skbuff.h>
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+#include <linux/ipv6.h>
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+#include <linux/netfilter.h>
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+#include <linux/netfilter_ipv6.h>
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+#include <net/secure_seq.h>
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+#include <net/checksum.h>
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+#include <net/ip6_route.h>
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+#include <net/ipv6.h>
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+
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+#include <net/netfilter/nf_conntrack_core.h>
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+#include <net/netfilter/nf_conntrack.h>
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+#include <net/netfilter/nf_nat_core.h>
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+#include <net/netfilter/nf_nat_l3proto.h>
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+#include <net/netfilter/nf_nat_l4proto.h>
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+
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+static const struct nf_nat_l3proto nf_nat_l3proto_ipv6;
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+
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+#ifdef CONFIG_XFRM
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+static void nf_nat_ipv6_decode_session(struct sk_buff *skb,
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+ const struct nf_conn *ct,
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+ enum ip_conntrack_dir dir,
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+ unsigned long statusbit,
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+ struct flowi *fl)
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+{
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+ const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
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+ struct flowi6 *fl6 = &fl->u.ip6;
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+
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+ if (ct->status & statusbit) {
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+ fl6->daddr = t->dst.u3.in6;
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+ if (t->dst.protonum == IPPROTO_TCP ||
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+ t->dst.protonum == IPPROTO_UDP ||
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+ t->dst.protonum == IPPROTO_UDPLITE ||
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+ t->dst.protonum == IPPROTO_DCCP ||
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+ t->dst.protonum == IPPROTO_SCTP)
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+ fl6->fl6_dport = t->dst.u.all;
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+ }
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+
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+ statusbit ^= IPS_NAT_MASK;
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+
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+ if (ct->status & statusbit) {
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+ fl6->saddr = t->src.u3.in6;
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+ if (t->dst.protonum == IPPROTO_TCP ||
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+ t->dst.protonum == IPPROTO_UDP ||
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+ t->dst.protonum == IPPROTO_UDPLITE ||
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+ t->dst.protonum == IPPROTO_DCCP ||
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+ t->dst.protonum == IPPROTO_SCTP)
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+ fl6->fl6_sport = t->src.u.all;
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+ }
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+}
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+#endif
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+
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+static bool nf_nat_ipv6_in_range(const struct nf_conntrack_tuple *t,
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+ const struct nf_nat_range *range)
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+{
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+ return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 &&
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+ ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0;
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+}
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+
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+static u32 nf_nat_ipv6_secure_port(const struct nf_conntrack_tuple *t,
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+ __be16 dport)
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+{
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+ return secure_ipv6_port_ephemeral(t->src.u3.ip6, t->dst.u3.ip6, dport);
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+}
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+
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+static bool nf_nat_ipv6_manip_pkt(struct sk_buff *skb,
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+ unsigned int iphdroff,
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+ const struct nf_nat_l4proto *l4proto,
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+ const struct nf_conntrack_tuple *target,
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+ enum nf_nat_manip_type maniptype)
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+{
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+ struct ipv6hdr *ipv6h;
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+ __be16 frag_off;
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+ int hdroff;
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+ u8 nexthdr;
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+
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+ if (!skb_make_writable(skb, iphdroff + sizeof(*ipv6h)))
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+ return false;
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+
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+ ipv6h = (void *)skb->data + iphdroff;
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+ nexthdr = ipv6h->nexthdr;
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+ hdroff = ipv6_skip_exthdr(skb, iphdroff + sizeof(*ipv6h),
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+ &nexthdr, &frag_off);
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+ if (hdroff < 0)
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+ goto manip_addr;
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+
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+ if ((frag_off & htons(~0x7)) == 0 &&
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+ !l4proto->manip_pkt(skb, &nf_nat_l3proto_ipv6, iphdroff, hdroff,
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+ target, maniptype))
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+ return false;
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+manip_addr:
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+ if (maniptype == NF_NAT_MANIP_SRC)
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+ ipv6h->saddr = target->src.u3.in6;
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+ else
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+ ipv6h->daddr = target->dst.u3.in6;
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+
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+ return true;
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+}
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+
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+static void nf_nat_ipv6_csum_update(struct sk_buff *skb,
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+ unsigned int iphdroff, __sum16 *check,
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+ const struct nf_conntrack_tuple *t,
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+ enum nf_nat_manip_type maniptype)
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+{
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+ const struct ipv6hdr *ipv6h = (struct ipv6hdr *)(skb->data + iphdroff);
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+ const struct in6_addr *oldip, *newip;
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+
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+ if (maniptype == NF_NAT_MANIP_SRC) {
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+ oldip = &ipv6h->saddr;
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+ newip = &t->src.u3.in6;
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+ } else {
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+ oldip = &ipv6h->daddr;
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+ newip = &t->dst.u3.in6;
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+ }
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+ inet_proto_csum_replace16(check, skb, oldip->s6_addr32,
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+ newip->s6_addr32, 1);
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+}
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+
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+static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb,
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+ u8 proto, void *data, __sum16 *check,
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+ int datalen, int oldlen)
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+{
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+ const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
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+ struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
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+
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+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
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+ if (!(rt->rt6i_flags & RTF_LOCAL) &&
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+ (!skb->dev || skb->dev->features & NETIF_F_V6_CSUM)) {
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+ skb->ip_summed = CHECKSUM_PARTIAL;
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+ skb->csum_start = skb_headroom(skb) +
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+ skb_network_offset(skb) +
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+ (data - (void *)skb->data);
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+ skb->csum_offset = (void *)check - data;
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+ *check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
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+ datalen, proto, 0);
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+ } else {
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+ *check = 0;
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+ *check = csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
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+ datalen, proto,
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+ csum_partial(data, datalen,
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+ 0));
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+ if (proto == IPPROTO_UDP && !*check)
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+ *check = CSUM_MANGLED_0;
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+ }
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+ } else
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+ inet_proto_csum_replace2(check, skb,
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+ htons(oldlen), htons(datalen), 1);
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+}
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+
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+static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
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+ struct nf_nat_range *range)
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+{
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+ if (tb[CTA_NAT_V6_MINIP]) {
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+ nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
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+ sizeof(struct in6_addr));
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+ range->flags |= NF_NAT_RANGE_MAP_IPS;
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+ }
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+
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+ if (tb[CTA_NAT_V6_MAXIP])
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+ nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
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+ sizeof(struct in6_addr));
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+ else
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+ range->max_addr = range->min_addr;
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+
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+ return 0;
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+}
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+
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+static const struct nf_nat_l3proto nf_nat_l3proto_ipv6 = {
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+ .l3proto = NFPROTO_IPV6,
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+ .secure_port = nf_nat_ipv6_secure_port,
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+ .in_range = nf_nat_ipv6_in_range,
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+ .manip_pkt = nf_nat_ipv6_manip_pkt,
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+ .csum_update = nf_nat_ipv6_csum_update,
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+ .csum_recalc = nf_nat_ipv6_csum_recalc,
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+ .nlattr_to_range = nf_nat_ipv6_nlattr_to_range,
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+#ifdef CONFIG_XFRM
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+ .decode_session = nf_nat_ipv6_decode_session,
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+#endif
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+};
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+
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+int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
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+ struct nf_conn *ct,
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+ enum ip_conntrack_info ctinfo,
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+ unsigned int hooknum,
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+ unsigned int hdrlen)
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+{
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+ struct {
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+ struct icmp6hdr icmp6;
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+ struct ipv6hdr ip6;
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+ } *inside;
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+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
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+ enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
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+ const struct nf_nat_l4proto *l4proto;
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+ struct nf_conntrack_tuple target;
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+ unsigned long statusbit;
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+
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+ NF_CT_ASSERT(ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED_REPLY);
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+
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+ if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
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+ return 0;
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+ if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6))
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+ return 0;
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+
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+ inside = (void *)skb->data + hdrlen;
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+ if (inside->icmp6.icmp6_type == NDISC_REDIRECT) {
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+ if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
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+ return 0;
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+ if (ct->status & IPS_NAT_MASK)
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+ return 0;
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+ }
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+
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+ if (manip == NF_NAT_MANIP_SRC)
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+ statusbit = IPS_SRC_NAT;
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+ else
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+ statusbit = IPS_DST_NAT;
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+
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+ /* Invert if this is reply direction */
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+ if (dir == IP_CT_DIR_REPLY)
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+ statusbit ^= IPS_NAT_MASK;
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+
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+ if (!(ct->status & statusbit))
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+ return 1;
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+
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+ l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, inside->ip6.nexthdr);
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+ if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6),
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+ l4proto, &ct->tuplehash[!dir].tuple, !manip))
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+ return 0;
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+
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+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
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+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
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+ inside = (void *)skb->data + hdrlen;
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+ inside->icmp6.icmp6_cksum = 0;
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+ inside->icmp6.icmp6_cksum =
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+ csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
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+ skb->len - hdrlen, IPPROTO_ICMPV6,
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+ csum_partial(&inside->icmp6,
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+ skb->len - hdrlen, 0));
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+ }
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+
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+ nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
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+ l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, IPPROTO_ICMPV6);
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+ if (!nf_nat_ipv6_manip_pkt(skb, 0, l4proto, &target, manip))
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+ return 0;
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+
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+ return 1;
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+}
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+EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation);
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+
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+static int __init nf_nat_l3proto_ipv6_init(void)
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+{
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+ int err;
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+
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+ err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
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+ if (err < 0)
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+ goto err1;
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+ err = nf_nat_l3proto_register(&nf_nat_l3proto_ipv6);
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+ if (err < 0)
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+ goto err2;
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+ return err;
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+
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+err2:
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+ nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
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+err1:
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+ return err;
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+}
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+
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+static void __exit nf_nat_l3proto_ipv6_exit(void)
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+{
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+ nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6);
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+ nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
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+}
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+
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+MODULE_LICENSE("GPL");
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+MODULE_ALIAS("nf-nat-" __stringify(AF_INET6));
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+
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+module_init(nf_nat_l3proto_ipv6_init);
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+module_exit(nf_nat_l3proto_ipv6_exit);
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Patrick McHardy