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- /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- * (C) 2006-2010 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.
- */
- #include <linux/types.h>
- #include <linux/timer.h>
- #include <linux/netfilter.h>
- #include <linux/in.h>
- #include <linux/icmp.h>
- #include <linux/seq_file.h>
- #include <net/ip.h>
- #include <net/checksum.h>
- #include <linux/netfilter_ipv4.h>
- #include <net/netfilter/nf_conntrack_tuple.h>
- #include <net/netfilter/nf_conntrack_l4proto.h>
- #include <net/netfilter/nf_conntrack_core.h>
- #include <net/netfilter/nf_conntrack_zones.h>
- #include <net/netfilter/nf_log.h>
- static unsigned int nf_ct_icmp_timeout __read_mostly = 30*HZ;
- static inline struct nf_icmp_net *icmp_pernet(struct net *net)
- {
- return &net->ct.nf_ct_proto.icmp;
- }
- static bool icmp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
- struct net *net, struct nf_conntrack_tuple *tuple)
- {
- const struct icmphdr *hp;
- struct icmphdr _hdr;
- hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
- if (hp == NULL)
- return false;
- tuple->dst.u.icmp.type = hp->type;
- tuple->src.u.icmp.id = hp->un.echo.id;
- tuple->dst.u.icmp.code = hp->code;
- return true;
- }
- /* Add 1; spaces filled with 0. */
- static const u_int8_t invmap[] = {
- [ICMP_ECHO] = ICMP_ECHOREPLY + 1,
- [ICMP_ECHOREPLY] = ICMP_ECHO + 1,
- [ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
- [ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
- [ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
- [ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
- [ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
- [ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1
- };
- static bool icmp_invert_tuple(struct nf_conntrack_tuple *tuple,
- const struct nf_conntrack_tuple *orig)
- {
- if (orig->dst.u.icmp.type >= sizeof(invmap) ||
- !invmap[orig->dst.u.icmp.type])
- return false;
- tuple->src.u.icmp.id = orig->src.u.icmp.id;
- tuple->dst.u.icmp.type = invmap[orig->dst.u.icmp.type] - 1;
- tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
- return true;
- }
- /* Print out the per-protocol part of the tuple. */
- static void icmp_print_tuple(struct seq_file *s,
- const struct nf_conntrack_tuple *tuple)
- {
- seq_printf(s, "type=%u code=%u id=%u ",
- tuple->dst.u.icmp.type,
- tuple->dst.u.icmp.code,
- ntohs(tuple->src.u.icmp.id));
- }
- static unsigned int *icmp_get_timeouts(struct net *net)
- {
- return &icmp_pernet(net)->timeout;
- }
- /* Returns verdict for packet, or -1 for invalid. */
- static int icmp_packet(struct nf_conn *ct,
- const struct sk_buff *skb,
- unsigned int dataoff,
- enum ip_conntrack_info ctinfo,
- u_int8_t pf,
- unsigned int hooknum,
- unsigned int *timeout)
- {
- /* Do not immediately delete the connection after the first
- successful reply to avoid excessive conntrackd traffic
- and also to handle correctly ICMP echo reply duplicates. */
- nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
- return NF_ACCEPT;
- }
- /* Called when a new connection for this protocol found. */
- static bool icmp_new(struct nf_conn *ct, const struct sk_buff *skb,
- unsigned int dataoff, unsigned int *timeouts)
- {
- static const u_int8_t valid_new[] = {
- [ICMP_ECHO] = 1,
- [ICMP_TIMESTAMP] = 1,
- [ICMP_INFO_REQUEST] = 1,
- [ICMP_ADDRESS] = 1
- };
- if (ct->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new) ||
- !valid_new[ct->tuplehash[0].tuple.dst.u.icmp.type]) {
- /* Can't create a new ICMP `conn' with this. */
- pr_debug("icmp: can't create new conn with type %u\n",
- ct->tuplehash[0].tuple.dst.u.icmp.type);
- nf_ct_dump_tuple_ip(&ct->tuplehash[0].tuple);
- return false;
- }
- return true;
- }
- /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
- static int
- icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
- enum ip_conntrack_info *ctinfo,
- unsigned int hooknum)
- {
- struct nf_conntrack_tuple innertuple, origtuple;
- const struct nf_conntrack_l4proto *innerproto;
- const struct nf_conntrack_tuple_hash *h;
- const struct nf_conntrack_zone *zone;
- struct nf_conntrack_zone tmp;
- NF_CT_ASSERT(skb->nfct == NULL);
- zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
- /* Are they talking about one of our connections? */
- if (!nf_ct_get_tuplepr(skb,
- skb_network_offset(skb) + ip_hdrlen(skb)
- + sizeof(struct icmphdr),
- PF_INET, net, &origtuple)) {
- pr_debug("icmp_error_message: failed to get tuple\n");
- return -NF_ACCEPT;
- }
- /* rcu_read_lock()ed by nf_hook_slow */
- innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum);
- /* Ordinarily, we'd expect the inverted tupleproto, but it's
- been preserved inside the ICMP. */
- if (!nf_ct_invert_tuple(&innertuple, &origtuple,
- &nf_conntrack_l3proto_ipv4, innerproto)) {
- pr_debug("icmp_error_message: no match\n");
- return -NF_ACCEPT;
- }
- *ctinfo = IP_CT_RELATED;
- h = nf_conntrack_find_get(net, zone, &innertuple);
- if (!h) {
- pr_debug("icmp_error_message: no match\n");
- return -NF_ACCEPT;
- }
- if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
- *ctinfo += IP_CT_IS_REPLY;
- /* Update skb to refer to this connection */
- skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
- skb->nfctinfo = *ctinfo;
- return NF_ACCEPT;
- }
- /* Small and modified version of icmp_rcv */
- static int
- icmp_error(struct net *net, struct nf_conn *tmpl,
- struct sk_buff *skb, unsigned int dataoff,
- enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
- {
- const struct icmphdr *icmph;
- struct icmphdr _ih;
- /* Not enough header? */
- icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih);
- if (icmph == NULL) {
- if (LOG_INVALID(net, IPPROTO_ICMP))
- nf_log_packet(net, PF_INET, 0, skb, NULL, NULL,
- NULL, "nf_ct_icmp: short packet ");
- return -NF_ACCEPT;
- }
- /* See ip_conntrack_proto_tcp.c */
- if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
- nf_ip_checksum(skb, hooknum, dataoff, 0)) {
- if (LOG_INVALID(net, IPPROTO_ICMP))
- nf_log_packet(net, PF_INET, 0, skb, NULL, NULL, NULL,
- "nf_ct_icmp: bad HW ICMP checksum ");
- return -NF_ACCEPT;
- }
- /*
- * 18 is the highest 'known' ICMP type. Anything else is a mystery
- *
- * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
- * discarded.
- */
- if (icmph->type > NR_ICMP_TYPES) {
- if (LOG_INVALID(net, IPPROTO_ICMP))
- nf_log_packet(net, PF_INET, 0, skb, NULL, NULL, NULL,
- "nf_ct_icmp: invalid ICMP type ");
- return -NF_ACCEPT;
- }
- /* Need to track icmp error message? */
- if (icmph->type != ICMP_DEST_UNREACH &&
- icmph->type != ICMP_SOURCE_QUENCH &&
- icmph->type != ICMP_TIME_EXCEEDED &&
- icmph->type != ICMP_PARAMETERPROB &&
- icmph->type != ICMP_REDIRECT)
- return NF_ACCEPT;
- return icmp_error_message(net, tmpl, skb, ctinfo, hooknum);
- }
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- #include <linux/netfilter/nfnetlink.h>
- #include <linux/netfilter/nfnetlink_conntrack.h>
- static int icmp_tuple_to_nlattr(struct sk_buff *skb,
- const struct nf_conntrack_tuple *t)
- {
- if (nla_put_be16(skb, CTA_PROTO_ICMP_ID, t->src.u.icmp.id) ||
- nla_put_u8(skb, CTA_PROTO_ICMP_TYPE, t->dst.u.icmp.type) ||
- nla_put_u8(skb, CTA_PROTO_ICMP_CODE, t->dst.u.icmp.code))
- goto nla_put_failure;
- return 0;
- nla_put_failure:
- return -1;
- }
- static const struct nla_policy icmp_nla_policy[CTA_PROTO_MAX+1] = {
- [CTA_PROTO_ICMP_TYPE] = { .type = NLA_U8 },
- [CTA_PROTO_ICMP_CODE] = { .type = NLA_U8 },
- [CTA_PROTO_ICMP_ID] = { .type = NLA_U16 },
- };
- static int icmp_nlattr_to_tuple(struct nlattr *tb[],
- struct nf_conntrack_tuple *tuple)
- {
- if (!tb[CTA_PROTO_ICMP_TYPE] ||
- !tb[CTA_PROTO_ICMP_CODE] ||
- !tb[CTA_PROTO_ICMP_ID])
- return -EINVAL;
- tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMP_TYPE]);
- tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMP_CODE]);
- tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMP_ID]);
- if (tuple->dst.u.icmp.type >= sizeof(invmap) ||
- !invmap[tuple->dst.u.icmp.type])
- return -EINVAL;
- return 0;
- }
- static int icmp_nlattr_tuple_size(void)
- {
- return nla_policy_len(icmp_nla_policy, CTA_PROTO_MAX + 1);
- }
- #endif
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
- #include <linux/netfilter/nfnetlink.h>
- #include <linux/netfilter/nfnetlink_cttimeout.h>
- static int icmp_timeout_nlattr_to_obj(struct nlattr *tb[],
- struct net *net, void *data)
- {
- unsigned int *timeout = data;
- struct nf_icmp_net *in = icmp_pernet(net);
- if (tb[CTA_TIMEOUT_ICMP_TIMEOUT]) {
- *timeout =
- ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMP_TIMEOUT])) * HZ;
- } else {
- /* Set default ICMP timeout. */
- *timeout = in->timeout;
- }
- return 0;
- }
- static int
- icmp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
- {
- const unsigned int *timeout = data;
- if (nla_put_be32(skb, CTA_TIMEOUT_ICMP_TIMEOUT, htonl(*timeout / HZ)))
- goto nla_put_failure;
- return 0;
- nla_put_failure:
- return -ENOSPC;
- }
- static const struct nla_policy
- icmp_timeout_nla_policy[CTA_TIMEOUT_ICMP_MAX+1] = {
- [CTA_TIMEOUT_ICMP_TIMEOUT] = { .type = NLA_U32 },
- };
- #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
- #ifdef CONFIG_SYSCTL
- static struct ctl_table icmp_sysctl_table[] = {
- {
- .procname = "nf_conntrack_icmp_timeout",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- { }
- };
- #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
- static struct ctl_table icmp_compat_sysctl_table[] = {
- {
- .procname = "ip_conntrack_icmp_timeout",
- .maxlen = sizeof(unsigned int),
- .mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
- },
- { }
- };
- #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
- #endif /* CONFIG_SYSCTL */
- static int icmp_kmemdup_sysctl_table(struct nf_proto_net *pn,
- struct nf_icmp_net *in)
- {
- #ifdef CONFIG_SYSCTL
- pn->ctl_table = kmemdup(icmp_sysctl_table,
- sizeof(icmp_sysctl_table),
- GFP_KERNEL);
- if (!pn->ctl_table)
- return -ENOMEM;
- pn->ctl_table[0].data = &in->timeout;
- #endif
- return 0;
- }
- static int icmp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn,
- struct nf_icmp_net *in)
- {
- #ifdef CONFIG_SYSCTL
- #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
- pn->ctl_compat_table = kmemdup(icmp_compat_sysctl_table,
- sizeof(icmp_compat_sysctl_table),
- GFP_KERNEL);
- if (!pn->ctl_compat_table)
- return -ENOMEM;
- pn->ctl_compat_table[0].data = &in->timeout;
- #endif
- #endif
- return 0;
- }
- static int icmp_init_net(struct net *net, u_int16_t proto)
- {
- int ret;
- struct nf_icmp_net *in = icmp_pernet(net);
- struct nf_proto_net *pn = &in->pn;
- in->timeout = nf_ct_icmp_timeout;
- ret = icmp_kmemdup_compat_sysctl_table(pn, in);
- if (ret < 0)
- return ret;
- ret = icmp_kmemdup_sysctl_table(pn, in);
- if (ret < 0)
- nf_ct_kfree_compat_sysctl_table(pn);
- return ret;
- }
- static struct nf_proto_net *icmp_get_net_proto(struct net *net)
- {
- return &net->ct.nf_ct_proto.icmp.pn;
- }
- struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly =
- {
- .l3proto = PF_INET,
- .l4proto = IPPROTO_ICMP,
- .name = "icmp",
- .pkt_to_tuple = icmp_pkt_to_tuple,
- .invert_tuple = icmp_invert_tuple,
- .print_tuple = icmp_print_tuple,
- .packet = icmp_packet,
- .get_timeouts = icmp_get_timeouts,
- .new = icmp_new,
- .error = icmp_error,
- .destroy = NULL,
- .me = NULL,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .tuple_to_nlattr = icmp_tuple_to_nlattr,
- .nlattr_tuple_size = icmp_nlattr_tuple_size,
- .nlattr_to_tuple = icmp_nlattr_to_tuple,
- .nla_policy = icmp_nla_policy,
- #endif
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
- .ctnl_timeout = {
- .nlattr_to_obj = icmp_timeout_nlattr_to_obj,
- .obj_to_nlattr = icmp_timeout_obj_to_nlattr,
- .nlattr_max = CTA_TIMEOUT_ICMP_MAX,
- .obj_size = sizeof(unsigned int),
- .nla_policy = icmp_timeout_nla_policy,
- },
- #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
- .init_net = icmp_init_net,
- .get_net_proto = icmp_get_net_proto,
- };
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