| /* |
| * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> |
| * |
| * 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. |
| * |
| * Development of IPv6 NAT funded by Astaro. |
| */ |
| #include <linux/types.h> |
| #include <linux/module.h> |
| #include <linux/skbuff.h> |
| #include <linux/ipv6.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv6.h> |
| #include <net/secure_seq.h> |
| #include <net/checksum.h> |
| #include <net/ip6_checksum.h> |
| #include <net/ip6_route.h> |
| #include <net/ipv6.h> |
| |
| #include <net/netfilter/nf_conntrack_core.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_nat_core.h> |
| #include <net/netfilter/nf_nat_l3proto.h> |
| #include <net/netfilter/nf_nat_l4proto.h> |
| |
| static const struct nf_nat_l3proto nf_nat_l3proto_ipv6; |
| |
| #ifdef CONFIG_XFRM |
| static void nf_nat_ipv6_decode_session(struct sk_buff *skb, |
| const struct nf_conn *ct, |
| enum ip_conntrack_dir dir, |
| unsigned long statusbit, |
| struct flowi *fl) |
| { |
| const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple; |
| struct flowi6 *fl6 = &fl->u.ip6; |
| |
| if (ct->status & statusbit) { |
| fl6->daddr = t->dst.u3.in6; |
| if (t->dst.protonum == IPPROTO_TCP || |
| t->dst.protonum == IPPROTO_UDP || |
| t->dst.protonum == IPPROTO_UDPLITE || |
| t->dst.protonum == IPPROTO_DCCP || |
| t->dst.protonum == IPPROTO_SCTP) |
| fl6->fl6_dport = t->dst.u.all; |
| } |
| |
| statusbit ^= IPS_NAT_MASK; |
| |
| if (ct->status & statusbit) { |
| fl6->saddr = t->src.u3.in6; |
| if (t->dst.protonum == IPPROTO_TCP || |
| t->dst.protonum == IPPROTO_UDP || |
| t->dst.protonum == IPPROTO_UDPLITE || |
| t->dst.protonum == IPPROTO_DCCP || |
| t->dst.protonum == IPPROTO_SCTP) |
| fl6->fl6_sport = t->src.u.all; |
| } |
| } |
| #endif |
| |
| static bool nf_nat_ipv6_in_range(const struct nf_conntrack_tuple *t, |
| const struct nf_nat_range *range) |
| { |
| return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 && |
| ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0; |
| } |
| |
| static u32 nf_nat_ipv6_secure_port(const struct nf_conntrack_tuple *t, |
| __be16 dport) |
| { |
| return secure_ipv6_port_ephemeral(t->src.u3.ip6, t->dst.u3.ip6, dport); |
| } |
| |
| static bool nf_nat_ipv6_manip_pkt(struct sk_buff *skb, |
| unsigned int iphdroff, |
| const struct nf_nat_l4proto *l4proto, |
| const struct nf_conntrack_tuple *target, |
| enum nf_nat_manip_type maniptype) |
| { |
| struct ipv6hdr *ipv6h; |
| __be16 frag_off; |
| int hdroff; |
| u8 nexthdr; |
| |
| if (!skb_make_writable(skb, iphdroff + sizeof(*ipv6h))) |
| return false; |
| |
| ipv6h = (void *)skb->data + iphdroff; |
| nexthdr = ipv6h->nexthdr; |
| hdroff = ipv6_skip_exthdr(skb, iphdroff + sizeof(*ipv6h), |
| &nexthdr, &frag_off); |
| if (hdroff < 0) |
| goto manip_addr; |
| |
| if ((frag_off & htons(~0x7)) == 0 && |
| !l4proto->manip_pkt(skb, &nf_nat_l3proto_ipv6, iphdroff, hdroff, |
| target, maniptype)) |
| return false; |
| manip_addr: |
| if (maniptype == NF_NAT_MANIP_SRC) |
| ipv6h->saddr = target->src.u3.in6; |
| else |
| ipv6h->daddr = target->dst.u3.in6; |
| |
| return true; |
| } |
| |
| static void nf_nat_ipv6_csum_update(struct sk_buff *skb, |
| unsigned int iphdroff, __sum16 *check, |
| const struct nf_conntrack_tuple *t, |
| enum nf_nat_manip_type maniptype) |
| { |
| const struct ipv6hdr *ipv6h = (struct ipv6hdr *)(skb->data + iphdroff); |
| const struct in6_addr *oldip, *newip; |
| |
| if (maniptype == NF_NAT_MANIP_SRC) { |
| oldip = &ipv6h->saddr; |
| newip = &t->src.u3.in6; |
| } else { |
| oldip = &ipv6h->daddr; |
| newip = &t->dst.u3.in6; |
| } |
| inet_proto_csum_replace16(check, skb, oldip->s6_addr32, |
| newip->s6_addr32, 1); |
| } |
| |
| static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb, |
| u8 proto, void *data, __sum16 *check, |
| int datalen, int oldlen) |
| { |
| const struct ipv6hdr *ipv6h = ipv6_hdr(skb); |
| struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); |
| |
| if (skb->ip_summed != CHECKSUM_PARTIAL) { |
| if (!(rt->rt6i_flags & RTF_LOCAL) && |
| (!skb->dev || skb->dev->features & NETIF_F_V6_CSUM)) { |
| skb->ip_summed = CHECKSUM_PARTIAL; |
| skb->csum_start = skb_headroom(skb) + |
| skb_network_offset(skb) + |
| (data - (void *)skb->data); |
| skb->csum_offset = (void *)check - data; |
| *check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, |
| datalen, proto, 0); |
| } else { |
| *check = 0; |
| *check = csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, |
| datalen, proto, |
| csum_partial(data, datalen, |
| 0)); |
| if (proto == IPPROTO_UDP && !*check) |
| *check = CSUM_MANGLED_0; |
| } |
| } else |
| inet_proto_csum_replace2(check, skb, |
| htons(oldlen), htons(datalen), 1); |
| } |
| |
| static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[], |
| struct nf_nat_range *range) |
| { |
| if (tb[CTA_NAT_V6_MINIP]) { |
| nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP], |
| sizeof(struct in6_addr)); |
| range->flags |= NF_NAT_RANGE_MAP_IPS; |
| } |
| |
| if (tb[CTA_NAT_V6_MAXIP]) |
| nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP], |
| sizeof(struct in6_addr)); |
| else |
| range->max_addr = range->min_addr; |
| |
| return 0; |
| } |
| |
| static const struct nf_nat_l3proto nf_nat_l3proto_ipv6 = { |
| .l3proto = NFPROTO_IPV6, |
| .secure_port = nf_nat_ipv6_secure_port, |
| .in_range = nf_nat_ipv6_in_range, |
| .manip_pkt = nf_nat_ipv6_manip_pkt, |
| .csum_update = nf_nat_ipv6_csum_update, |
| .csum_recalc = nf_nat_ipv6_csum_recalc, |
| .nlattr_to_range = nf_nat_ipv6_nlattr_to_range, |
| #ifdef CONFIG_XFRM |
| .decode_session = nf_nat_ipv6_decode_session, |
| #endif |
| }; |
| |
| int nf_nat_icmpv6_reply_translation(struct sk_buff *skb, |
| struct nf_conn *ct, |
| enum ip_conntrack_info ctinfo, |
| unsigned int hooknum, |
| unsigned int hdrlen) |
| { |
| struct { |
| struct icmp6hdr icmp6; |
| struct ipv6hdr ip6; |
| } *inside; |
| enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| enum nf_nat_manip_type manip = HOOK2MANIP(hooknum); |
| const struct nf_nat_l4proto *l4proto; |
| struct nf_conntrack_tuple target; |
| unsigned long statusbit; |
| |
| NF_CT_ASSERT(ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED_REPLY); |
| |
| if (!skb_make_writable(skb, hdrlen + sizeof(*inside))) |
| return 0; |
| if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6)) |
| return 0; |
| |
| inside = (void *)skb->data + hdrlen; |
| if (inside->icmp6.icmp6_type == NDISC_REDIRECT) { |
| if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK) |
| return 0; |
| if (ct->status & IPS_NAT_MASK) |
| return 0; |
| } |
| |
| if (manip == NF_NAT_MANIP_SRC) |
| statusbit = IPS_SRC_NAT; |
| else |
| statusbit = IPS_DST_NAT; |
| |
| /* Invert if this is reply direction */ |
| if (dir == IP_CT_DIR_REPLY) |
| statusbit ^= IPS_NAT_MASK; |
| |
| if (!(ct->status & statusbit)) |
| return 1; |
| |
| l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, inside->ip6.nexthdr); |
| if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6), |
| l4proto, &ct->tuplehash[!dir].tuple, !manip)) |
| return 0; |
| |
| if (skb->ip_summed != CHECKSUM_PARTIAL) { |
| struct ipv6hdr *ipv6h = ipv6_hdr(skb); |
| inside = (void *)skb->data + hdrlen; |
| inside->icmp6.icmp6_cksum = 0; |
| inside->icmp6.icmp6_cksum = |
| csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, |
| skb->len - hdrlen, IPPROTO_ICMPV6, |
| csum_partial(&inside->icmp6, |
| skb->len - hdrlen, 0)); |
| } |
| |
| nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); |
| l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, IPPROTO_ICMPV6); |
| if (!nf_nat_ipv6_manip_pkt(skb, 0, l4proto, &target, manip)) |
| return 0; |
| |
| return 1; |
| } |
| EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation); |
| |
| static int __init nf_nat_l3proto_ipv6_init(void) |
| { |
| int err; |
| |
| err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6); |
| if (err < 0) |
| goto err1; |
| err = nf_nat_l3proto_register(&nf_nat_l3proto_ipv6); |
| if (err < 0) |
| goto err2; |
| return err; |
| |
| err2: |
| nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6); |
| err1: |
| return err; |
| } |
| |
| static void __exit nf_nat_l3proto_ipv6_exit(void) |
| { |
| nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6); |
| nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6); |
| } |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("nf-nat-" __stringify(AF_INET6)); |
| |
| module_init(nf_nat_l3proto_ipv6_init); |
| module_exit(nf_nat_l3proto_ipv6_exit); |