324 lines
9.2 KiB
C
324 lines
9.2 KiB
C
/*
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* Copyright (C)2003,2004 USAGI/WIDE Project
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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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* Author:
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* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
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*
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* 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
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* - ICMPv6 tracking support. Derived from the original ip_conntrack code
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* net/ipv4/netfilter/ip_conntrack_proto_icmp.c which had the following
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* copyright information:
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* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*/
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <linux/in6.h>
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#include <linux/icmpv6.h>
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#include <net/ip6_checksum.h>
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#include <linux/seq_file.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/netfilter/nf_conntrack_tuple.h>
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#include <net/netfilter/nf_conntrack_protocol.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
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unsigned long nf_ct_icmpv6_timeout = 30*HZ;
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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static int icmpv6_pkt_to_tuple(const struct sk_buff *skb,
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unsigned int dataoff,
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struct nf_conntrack_tuple *tuple)
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{
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struct icmp6hdr _hdr, *hp;
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hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
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if (hp == NULL)
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return 0;
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tuple->dst.u.icmp.type = hp->icmp6_type;
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tuple->src.u.icmp.id = hp->icmp6_identifier;
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tuple->dst.u.icmp.code = hp->icmp6_code;
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return 1;
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}
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/* Add 1; spaces filled with 0. */
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static u_int8_t invmap[] = {
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[ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
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[ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
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[ICMPV6_NI_QUERY - 128] = ICMPV6_NI_QUERY + 1,
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[ICMPV6_NI_REPLY - 128] = ICMPV6_NI_REPLY +1
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};
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static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
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const struct nf_conntrack_tuple *orig)
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{
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int type = orig->dst.u.icmp.type - 128;
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if (type < 0 || type >= sizeof(invmap) || !invmap[type])
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return 0;
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tuple->src.u.icmp.id = orig->src.u.icmp.id;
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tuple->dst.u.icmp.type = invmap[type] - 1;
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tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
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return 1;
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}
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/* Print out the per-protocol part of the tuple. */
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static int icmpv6_print_tuple(struct seq_file *s,
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const struct nf_conntrack_tuple *tuple)
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{
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return seq_printf(s, "type=%u code=%u id=%u ",
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tuple->dst.u.icmp.type,
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tuple->dst.u.icmp.code,
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ntohs(tuple->src.u.icmp.id));
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}
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/* Print out the private part of the conntrack. */
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static int icmpv6_print_conntrack(struct seq_file *s,
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const struct nf_conn *conntrack)
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{
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return 0;
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}
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/* Returns verdict for packet, or -1 for invalid. */
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static int icmpv6_packet(struct nf_conn *ct,
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const struct sk_buff *skb,
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unsigned int dataoff,
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enum ip_conntrack_info ctinfo,
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int pf,
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unsigned int hooknum)
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{
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/* Try to delete connection immediately after all replies:
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won't actually vanish as we still have skb, and del_timer
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means this will only run once even if count hits zero twice
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(theoretically possible with SMP) */
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if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
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if (atomic_dec_and_test(&ct->proto.icmp.count)
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&& del_timer(&ct->timeout))
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ct->timeout.function((unsigned long)ct);
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} else {
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atomic_inc(&ct->proto.icmp.count);
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nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
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nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
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}
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return NF_ACCEPT;
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}
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/* Called when a new connection for this protocol found. */
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static int icmpv6_new(struct nf_conn *conntrack,
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const struct sk_buff *skb,
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unsigned int dataoff)
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{
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static u_int8_t valid_new[] = {
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[ICMPV6_ECHO_REQUEST - 128] = 1,
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[ICMPV6_NI_QUERY - 128] = 1
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};
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int type = conntrack->tuplehash[0].tuple.dst.u.icmp.type - 128;
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if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
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/* Can't create a new ICMPv6 `conn' with this. */
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DEBUGP("icmpv6: can't create new conn with type %u\n",
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type + 128);
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NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
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return 0;
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}
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atomic_set(&conntrack->proto.icmp.count, 0);
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return 1;
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}
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extern int
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nf_ct_ipv6_skip_exthdr(struct sk_buff *skb, int start, u8 *nexthdrp, int len);
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extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6;
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static int
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icmpv6_error_message(struct sk_buff *skb,
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unsigned int icmp6off,
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enum ip_conntrack_info *ctinfo,
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unsigned int hooknum)
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{
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struct nf_conntrack_tuple intuple, origtuple;
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struct nf_conntrack_tuple_hash *h;
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struct icmp6hdr _hdr, *hp;
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unsigned int inip6off;
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struct nf_conntrack_protocol *inproto;
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u_int8_t inprotonum;
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unsigned int inprotoff;
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NF_CT_ASSERT(skb->nfct == NULL);
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hp = skb_header_pointer(skb, icmp6off, sizeof(_hdr), &_hdr);
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if (hp == NULL) {
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DEBUGP("icmpv6_error: Can't get ICMPv6 hdr.\n");
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return -NF_ACCEPT;
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}
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inip6off = icmp6off + sizeof(_hdr);
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if (skb_copy_bits(skb, inip6off+offsetof(struct ipv6hdr, nexthdr),
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&inprotonum, sizeof(inprotonum)) != 0) {
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DEBUGP("icmpv6_error: Can't get nexthdr in inner IPv6 header.\n");
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return -NF_ACCEPT;
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}
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inprotoff = nf_ct_ipv6_skip_exthdr(skb,
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inip6off + sizeof(struct ipv6hdr),
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&inprotonum,
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skb->len - inip6off
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- sizeof(struct ipv6hdr));
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if ((inprotoff < 0) || (inprotoff > skb->len) ||
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(inprotonum == NEXTHDR_FRAGMENT)) {
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DEBUGP("icmpv6_error: Can't get protocol header in ICMPv6 payload.\n");
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return -NF_ACCEPT;
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}
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inproto = __nf_ct_proto_find(PF_INET6, inprotonum);
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/* Are they talking about one of our connections? */
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if (!nf_ct_get_tuple(skb, inip6off, inprotoff, PF_INET6, inprotonum,
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&origtuple, &nf_conntrack_l3proto_ipv6, inproto)) {
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DEBUGP("icmpv6_error: Can't get tuple\n");
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return -NF_ACCEPT;
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}
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/* Ordinarily, we'd expect the inverted tupleproto, but it's
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been preserved inside the ICMP. */
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if (!nf_ct_invert_tuple(&intuple, &origtuple,
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&nf_conntrack_l3proto_ipv6, inproto)) {
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DEBUGP("icmpv6_error: Can't invert tuple\n");
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return -NF_ACCEPT;
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}
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*ctinfo = IP_CT_RELATED;
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h = nf_conntrack_find_get(&intuple, NULL);
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if (!h) {
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DEBUGP("icmpv6_error: no match\n");
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return -NF_ACCEPT;
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} else {
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if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
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*ctinfo += IP_CT_IS_REPLY;
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}
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/* Update skb to refer to this connection */
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skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
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skb->nfctinfo = *ctinfo;
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return -NF_ACCEPT;
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}
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static int
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icmpv6_error(struct sk_buff *skb, unsigned int dataoff,
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enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
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{
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struct icmp6hdr _ih, *icmp6h;
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icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
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if (icmp6h == NULL) {
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if (LOG_INVALID(IPPROTO_ICMPV6))
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nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
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"nf_ct_icmpv6: short packet ");
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return -NF_ACCEPT;
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}
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if (hooknum == NF_IP6_PRE_ROUTING &&
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nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
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nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
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"nf_ct_icmpv6: ICMPv6 checksum failed\n");
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return -NF_ACCEPT;
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}
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/* is not error message ? */
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if (icmp6h->icmp6_type >= 128)
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return NF_ACCEPT;
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return icmpv6_error_message(skb, dataoff, ctinfo, hooknum);
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}
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#if defined(CONFIG_NF_CT_NETLINK) || \
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defined(CONFIG_NF_CT_NETLINK_MODULE)
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_conntrack.h>
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static int icmpv6_tuple_to_nfattr(struct sk_buff *skb,
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const struct nf_conntrack_tuple *t)
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{
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NFA_PUT(skb, CTA_PROTO_ICMPV6_ID, sizeof(u_int16_t),
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&t->src.u.icmp.id);
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NFA_PUT(skb, CTA_PROTO_ICMPV6_TYPE, sizeof(u_int8_t),
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&t->dst.u.icmp.type);
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NFA_PUT(skb, CTA_PROTO_ICMPV6_CODE, sizeof(u_int8_t),
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&t->dst.u.icmp.code);
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return 0;
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nfattr_failure:
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return -1;
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}
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static const size_t cta_min_proto[CTA_PROTO_MAX] = {
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[CTA_PROTO_ICMPV6_TYPE-1] = sizeof(u_int8_t),
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[CTA_PROTO_ICMPV6_CODE-1] = sizeof(u_int8_t),
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[CTA_PROTO_ICMPV6_ID-1] = sizeof(u_int16_t)
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};
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static int icmpv6_nfattr_to_tuple(struct nfattr *tb[],
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struct nf_conntrack_tuple *tuple)
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{
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if (!tb[CTA_PROTO_ICMPV6_TYPE-1]
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|| !tb[CTA_PROTO_ICMPV6_CODE-1]
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|| !tb[CTA_PROTO_ICMPV6_ID-1])
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return -EINVAL;
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if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
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return -EINVAL;
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tuple->dst.u.icmp.type =
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*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_TYPE-1]);
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tuple->dst.u.icmp.code =
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*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_CODE-1]);
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tuple->src.u.icmp.id =
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*(u_int16_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_ID-1]);
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if (tuple->dst.u.icmp.type < 128
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|| tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
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|| !invmap[tuple->dst.u.icmp.type - 128])
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return -EINVAL;
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return 0;
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}
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#endif
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struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6 =
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{
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.l3proto = PF_INET6,
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.proto = IPPROTO_ICMPV6,
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.name = "icmpv6",
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.pkt_to_tuple = icmpv6_pkt_to_tuple,
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.invert_tuple = icmpv6_invert_tuple,
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.print_tuple = icmpv6_print_tuple,
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.print_conntrack = icmpv6_print_conntrack,
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.packet = icmpv6_packet,
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.new = icmpv6_new,
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.error = icmpv6_error,
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#if defined(CONFIG_NF_CT_NETLINK) || \
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defined(CONFIG_NF_CT_NETLINK_MODULE)
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.tuple_to_nfattr = icmpv6_tuple_to_nfattr,
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.nfattr_to_tuple = icmpv6_nfattr_to_tuple,
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#endif
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};
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EXPORT_SYMBOL(nf_conntrack_protocol_icmpv6);
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