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- /*
- * 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.
- *
- * Based on Rusty Russell's IPv4 ICMP NAT code. Development of IPv6
- * NAT funded by Astaro.
- */
- #include <linux/types.h>
- #include <linux/init.h>
- #include <linux/icmpv6.h>
- #include <linux/netfilter.h>
- #include <net/netfilter/nf_nat.h>
- #include <net/netfilter/nf_nat_core.h>
- #include <net/netfilter/nf_nat_l3proto.h>
- #include <net/netfilter/nf_nat_l4proto.h>
- static bool
- icmpv6_in_range(const struct nf_conntrack_tuple *tuple,
- enum nf_nat_manip_type maniptype,
- const union nf_conntrack_man_proto *min,
- const union nf_conntrack_man_proto *max)
- {
- return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
- ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
- }
- static void
- icmpv6_unique_tuple(const struct nf_nat_l3proto *l3proto,
- struct nf_conntrack_tuple *tuple,
- const struct nf_nat_range *range,
- enum nf_nat_manip_type maniptype,
- const struct nf_conn *ct)
- {
- static u16 id;
- unsigned int range_size;
- unsigned int i;
- range_size = ntohs(range->max_proto.icmp.id) -
- ntohs(range->min_proto.icmp.id) + 1;
- if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED))
- range_size = 0xffff;
- for (i = 0; ; ++id) {
- tuple->src.u.icmp.id = htons(ntohs(range->min_proto.icmp.id) +
- (id % range_size));
- if (++i == range_size || !nf_nat_used_tuple(tuple, ct))
- return;
- }
- }
- static bool
- icmpv6_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
- unsigned int iphdroff, unsigned int hdroff,
- const struct nf_conntrack_tuple *tuple,
- enum nf_nat_manip_type maniptype)
- {
- struct icmp6hdr *hdr;
- if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
- return false;
- hdr = (struct icmp6hdr *)(skb->data + hdroff);
- l3proto->csum_update(skb, iphdroff, &hdr->icmp6_cksum,
- tuple, maniptype);
- if (hdr->icmp6_type == ICMPV6_ECHO_REQUEST ||
- hdr->icmp6_type == ICMPV6_ECHO_REPLY) {
- inet_proto_csum_replace2(&hdr->icmp6_cksum, skb,
- hdr->icmp6_identifier,
- tuple->src.u.icmp.id, false);
- hdr->icmp6_identifier = tuple->src.u.icmp.id;
- }
- return true;
- }
- const struct nf_nat_l4proto nf_nat_l4proto_icmpv6 = {
- .l4proto = IPPROTO_ICMPV6,
- .manip_pkt = icmpv6_manip_pkt,
- .in_range = icmpv6_in_range,
- .unique_tuple = icmpv6_unique_tuple,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
- #endif
- };
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