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![Daniel Borkmann](/assets/img/avatar_default.png)
This work adds the possibility of deriving the zone id from the skb->mark field in a scalable manner. This allows for having only a single template serving hundreds/thousands of different zones, for example, instead of the need to have one match for each zone as an extra CT jump target. Note that we'd need to have this information attached to the template as at the time when we're trying to lookup a possible ct object, we already need to know zone information for a possible match when going into __nf_conntrack_find_get(). This work provides a minimal implementation for a possible mapping. In order to not add/expose an extra ct->status bit, the zone structure has been extended to carry a flag for deriving the mark. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
397 lines
11 KiB
C
397 lines
11 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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#include <linux/types.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_l4proto.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_zones.h>
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#include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
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#include <net/netfilter/nf_log.h>
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static unsigned int nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
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static inline struct nf_icmp_net *icmpv6_pernet(struct net *net)
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{
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return &net->ct.nf_ct_proto.icmpv6;
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}
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static bool 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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const struct icmp6hdr *hp;
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struct icmp6hdr _hdr;
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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 false;
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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 true;
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}
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/* Add 1; spaces filled with 0. */
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static const 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_REPLY + 1,
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[ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY +1
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};
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static const u_int8_t noct_valid_new[] = {
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[ICMPV6_MGM_QUERY - 130] = 1,
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[ICMPV6_MGM_REPORT -130] = 1,
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[ICMPV6_MGM_REDUCTION - 130] = 1,
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[NDISC_ROUTER_SOLICITATION - 130] = 1,
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[NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
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[NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
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[NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
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[ICMPV6_MLD2_REPORT - 130] = 1
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};
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static bool 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 false;
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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 true;
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}
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/* Print out the per-protocol part of the tuple. */
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static void 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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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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static unsigned int *icmpv6_get_timeouts(struct net *net)
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{
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return &icmpv6_pernet(net)->timeout;
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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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u_int8_t pf,
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unsigned int hooknum,
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unsigned int *timeout)
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{
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/* Do not immediately delete the connection after the first
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successful reply to avoid excessive conntrackd traffic
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and also to handle correctly ICMP echo reply duplicates. */
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nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
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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 bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
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unsigned int dataoff, unsigned int *timeouts)
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{
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static const 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 = ct->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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pr_debug("icmpv6: can't create new conn with type %u\n",
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type + 128);
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nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
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if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
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nf_log_packet(nf_ct_net(ct), PF_INET6, 0, skb, NULL,
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NULL, NULL,
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"nf_ct_icmpv6: invalid new with type %d ",
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type + 128);
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return false;
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}
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return true;
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}
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static int
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icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
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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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const struct nf_conntrack_tuple_hash *h;
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const struct nf_conntrack_l4proto *inproto;
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struct nf_conntrack_zone tmp;
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NF_CT_ASSERT(skb->nfct == NULL);
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/* Are they talking about one of our connections? */
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if (!nf_ct_get_tuplepr(skb,
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skb_network_offset(skb)
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+ sizeof(struct ipv6hdr)
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+ sizeof(struct icmp6hdr),
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PF_INET6, &origtuple)) {
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pr_debug("icmpv6_error: Can't get tuple\n");
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return -NF_ACCEPT;
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}
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/* rcu_read_lock()ed by nf_hook_slow */
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inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
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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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pr_debug("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(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
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&intuple);
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if (!h) {
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pr_debug("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 net *net, struct nf_conn *tmpl,
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struct sk_buff *skb, unsigned int dataoff,
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enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
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{
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const struct icmp6hdr *icmp6h;
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struct icmp6hdr _ih;
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int type;
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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(net, IPPROTO_ICMPV6))
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nf_log_packet(net, 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 (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
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nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
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if (LOG_INVALID(net, IPPROTO_ICMPV6))
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nf_log_packet(net, PF_INET6, 0, skb, NULL, NULL, NULL,
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"nf_ct_icmpv6: ICMPv6 checksum failed ");
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return -NF_ACCEPT;
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}
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type = icmp6h->icmp6_type - 130;
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if (type >= 0 && type < sizeof(noct_valid_new) &&
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noct_valid_new[type]) {
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skb->nfct = &nf_ct_untracked_get()->ct_general;
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skb->nfctinfo = IP_CT_NEW;
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nf_conntrack_get(skb->nfct);
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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(net, tmpl, skb, dataoff, ctinfo, hooknum);
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}
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
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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_nlattr(struct sk_buff *skb,
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const struct nf_conntrack_tuple *t)
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{
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if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
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nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
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nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
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[CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
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[CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
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[CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
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};
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static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
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struct nf_conntrack_tuple *tuple)
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{
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if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
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!tb[CTA_PROTO_ICMPV6_CODE] ||
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!tb[CTA_PROTO_ICMPV6_ID])
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return -EINVAL;
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tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
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tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
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tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
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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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static int icmpv6_nlattr_tuple_size(void)
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{
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return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
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}
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_cttimeout.h>
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static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
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struct net *net, void *data)
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{
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unsigned int *timeout = data;
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struct nf_icmp_net *in = icmpv6_pernet(net);
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if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
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*timeout =
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ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
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} else {
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/* Set default ICMPv6 timeout. */
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*timeout = in->timeout;
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}
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return 0;
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}
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static int
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icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
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{
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const unsigned int *timeout = data;
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if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -ENOSPC;
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}
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static const struct nla_policy
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icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
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[CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
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};
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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#ifdef CONFIG_SYSCTL
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static struct ctl_table icmpv6_sysctl_table[] = {
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{
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.procname = "nf_conntrack_icmpv6_timeout",
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_jiffies,
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},
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{ }
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};
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#endif /* CONFIG_SYSCTL */
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static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
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struct nf_icmp_net *in)
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{
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#ifdef CONFIG_SYSCTL
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pn->ctl_table = kmemdup(icmpv6_sysctl_table,
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sizeof(icmpv6_sysctl_table),
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GFP_KERNEL);
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if (!pn->ctl_table)
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return -ENOMEM;
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pn->ctl_table[0].data = &in->timeout;
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#endif
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return 0;
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}
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static int icmpv6_init_net(struct net *net, u_int16_t proto)
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{
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struct nf_icmp_net *in = icmpv6_pernet(net);
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struct nf_proto_net *pn = &in->pn;
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in->timeout = nf_ct_icmpv6_timeout;
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return icmpv6_kmemdup_sysctl_table(pn, in);
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}
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static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
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{
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return &net->ct.nf_ct_proto.icmpv6.pn;
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}
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struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
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{
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.l3proto = PF_INET6,
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.l4proto = 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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.packet = icmpv6_packet,
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.get_timeouts = icmpv6_get_timeouts,
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.new = icmpv6_new,
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.error = icmpv6_error,
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
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.tuple_to_nlattr = icmpv6_tuple_to_nlattr,
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.nlattr_tuple_size = icmpv6_nlattr_tuple_size,
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.nlattr_to_tuple = icmpv6_nlattr_to_tuple,
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.nla_policy = icmpv6_nla_policy,
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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.ctnl_timeout = {
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.nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
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.obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
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.nlattr_max = CTA_TIMEOUT_ICMP_MAX,
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.obj_size = sizeof(unsigned int),
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.nla_policy = icmpv6_timeout_nla_policy,
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},
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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.init_net = icmpv6_init_net,
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.get_net_proto = icmpv6_get_net_proto,
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};
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