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![Florian Westphal](/assets/img/avatar_default.png)
We currently call ->nlattr_tuple_size() once at register time and cache result in l4proto->nla_size. nla_size is the only member that is written to, avoiding this would allow to make l4proto trackers const. We can use ->nlattr_tuple_size() at run time, and cache result in the individual trackers instead. This is an intermediate step, next patch removes nlattr_size() callback and computes size at compile time, then removes nla_size. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
383 lines
10 KiB
C
383 lines
10 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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* (C) 2006-2010 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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#include <linux/types.h>
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#include <linux/timer.h>
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#include <linux/netfilter.h>
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#include <linux/in.h>
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#include <linux/icmp.h>
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#include <linux/seq_file.h>
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#include <net/ip.h>
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#include <net/checksum.h>
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#include <linux/netfilter_ipv4.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/nf_log.h>
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static unsigned int nf_ct_icmp_timeout __read_mostly = 30*HZ;
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static inline struct nf_icmp_net *icmp_pernet(struct net *net)
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{
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return &net->ct.nf_ct_proto.icmp;
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}
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static bool icmp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
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struct net *net, struct nf_conntrack_tuple *tuple)
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{
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const struct icmphdr *hp;
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struct icmphdr _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->type;
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tuple->src.u.icmp.id = hp->un.echo.id;
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tuple->dst.u.icmp.code = hp->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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[ICMP_ECHO] = ICMP_ECHOREPLY + 1,
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[ICMP_ECHOREPLY] = ICMP_ECHO + 1,
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[ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
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[ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
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[ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
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[ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
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[ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
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[ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1
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};
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static bool icmp_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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if (orig->dst.u.icmp.type >= sizeof(invmap) ||
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!invmap[orig->dst.u.icmp.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[orig->dst.u.icmp.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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static unsigned int *icmp_get_timeouts(struct net *net)
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{
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return &icmp_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 icmp_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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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 icmp_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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[ICMP_ECHO] = 1,
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[ICMP_TIMESTAMP] = 1,
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[ICMP_INFO_REQUEST] = 1,
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[ICMP_ADDRESS] = 1
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};
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if (ct->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new) ||
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!valid_new[ct->tuplehash[0].tuple.dst.u.icmp.type]) {
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/* Can't create a new ICMP `conn' with this. */
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pr_debug("icmp: can't create new conn with type %u\n",
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ct->tuplehash[0].tuple.dst.u.icmp.type);
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nf_ct_dump_tuple_ip(&ct->tuplehash[0].tuple);
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return false;
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}
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return true;
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}
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/* Returns conntrack if it dealt with ICMP, and filled in skb fields */
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static int
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icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
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unsigned int hooknum)
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{
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struct nf_conntrack_tuple innertuple, origtuple;
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const struct nf_conntrack_l4proto *innerproto;
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const struct nf_conntrack_tuple_hash *h;
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const struct nf_conntrack_zone *zone;
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enum ip_conntrack_info ctinfo;
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struct nf_conntrack_zone tmp;
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WARN_ON(skb_nfct(skb));
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zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
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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) + ip_hdrlen(skb)
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+ sizeof(struct icmphdr),
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PF_INET, net, &origtuple)) {
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pr_debug("icmp_error_message: failed to 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_thresh */
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innerproto = __nf_ct_l4proto_find(PF_INET, 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(&innertuple, &origtuple,
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&nf_conntrack_l3proto_ipv4, innerproto)) {
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pr_debug("icmp_error_message: no match\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, zone, &innertuple);
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if (!h) {
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pr_debug("icmp_error_message: no match\n");
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return -NF_ACCEPT;
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}
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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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/* Update skb to refer to this connection */
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nf_ct_set(skb, nf_ct_tuplehash_to_ctrack(h), ctinfo);
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return NF_ACCEPT;
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}
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static void icmp_error_log(const struct sk_buff *skb, struct net *net,
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u8 pf, const char *msg)
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{
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nf_l4proto_log_invalid(skb, net, pf, IPPROTO_ICMP, "%s", msg);
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}
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/* Small and modified version of icmp_rcv */
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static int
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icmp_error(struct net *net, struct nf_conn *tmpl,
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struct sk_buff *skb, unsigned int dataoff,
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u8 pf, unsigned int hooknum)
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{
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const struct icmphdr *icmph;
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struct icmphdr _ih;
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/* Not enough header? */
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icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih);
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if (icmph == NULL) {
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icmp_error_log(skb, net, pf, "short packet");
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return -NF_ACCEPT;
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}
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/* See ip_conntrack_proto_tcp.c */
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if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
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nf_ip_checksum(skb, hooknum, dataoff, 0)) {
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icmp_error_log(skb, net, pf, "bad hw icmp checksum");
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return -NF_ACCEPT;
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}
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/*
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* 18 is the highest 'known' ICMP type. Anything else is a mystery
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*
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* RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
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* discarded.
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*/
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if (icmph->type > NR_ICMP_TYPES) {
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icmp_error_log(skb, net, pf, "invalid icmp type");
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return -NF_ACCEPT;
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}
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/* Need to track icmp error message? */
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if (icmph->type != ICMP_DEST_UNREACH &&
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icmph->type != ICMP_SOURCE_QUENCH &&
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icmph->type != ICMP_TIME_EXCEEDED &&
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icmph->type != ICMP_PARAMETERPROB &&
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icmph->type != ICMP_REDIRECT)
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return NF_ACCEPT;
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return icmp_error_message(net, tmpl, skb, 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 icmp_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_ICMP_ID, t->src.u.icmp.id) ||
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nla_put_u8(skb, CTA_PROTO_ICMP_TYPE, t->dst.u.icmp.type) ||
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nla_put_u8(skb, CTA_PROTO_ICMP_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 icmp_nla_policy[CTA_PROTO_MAX+1] = {
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[CTA_PROTO_ICMP_TYPE] = { .type = NLA_U8 },
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[CTA_PROTO_ICMP_CODE] = { .type = NLA_U8 },
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[CTA_PROTO_ICMP_ID] = { .type = NLA_U16 },
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};
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static int icmp_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_ICMP_TYPE] ||
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!tb[CTA_PROTO_ICMP_CODE] ||
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!tb[CTA_PROTO_ICMP_ID])
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return -EINVAL;
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tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMP_TYPE]);
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tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMP_CODE]);
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tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMP_ID]);
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if (tuple->dst.u.icmp.type >= sizeof(invmap) ||
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!invmap[tuple->dst.u.icmp.type])
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return -EINVAL;
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return 0;
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}
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static unsigned int icmp_nlattr_tuple_size(void)
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{
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static unsigned int size __read_mostly;
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if (!size)
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size = nla_policy_len(icmp_nla_policy, CTA_PROTO_MAX + 1);
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return size;
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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 icmp_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 = icmp_pernet(net);
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if (tb[CTA_TIMEOUT_ICMP_TIMEOUT]) {
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*timeout =
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ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMP_TIMEOUT])) * HZ;
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} else {
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/* Set default ICMP 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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icmp_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_ICMP_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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icmp_timeout_nla_policy[CTA_TIMEOUT_ICMP_MAX+1] = {
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[CTA_TIMEOUT_ICMP_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 icmp_sysctl_table[] = {
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{
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.procname = "nf_conntrack_icmp_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 icmp_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(icmp_sysctl_table,
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sizeof(icmp_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 icmp_init_net(struct net *net, u_int16_t proto)
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{
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struct nf_icmp_net *in = icmp_pernet(net);
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struct nf_proto_net *pn = &in->pn;
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in->timeout = nf_ct_icmp_timeout;
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return icmp_kmemdup_sysctl_table(pn, in);
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}
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static struct nf_proto_net *icmp_get_net_proto(struct net *net)
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{
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return &net->ct.nf_ct_proto.icmp.pn;
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}
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struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly =
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{
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.l3proto = PF_INET,
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.l4proto = IPPROTO_ICMP,
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.pkt_to_tuple = icmp_pkt_to_tuple,
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.invert_tuple = icmp_invert_tuple,
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.packet = icmp_packet,
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.get_timeouts = icmp_get_timeouts,
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.new = icmp_new,
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.error = icmp_error,
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.destroy = NULL,
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.me = NULL,
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
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.tuple_to_nlattr = icmp_tuple_to_nlattr,
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.nlattr_tuple_size = icmp_nlattr_tuple_size,
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.nlattr_to_tuple = icmp_nlattr_to_tuple,
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.nla_policy = icmp_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 = icmp_timeout_nlattr_to_obj,
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.obj_to_nlattr = icmp_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 = icmp_timeout_nla_policy,
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},
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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.init_net = icmp_init_net,
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.get_net_proto = icmp_get_net_proto,
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};
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