--- /dev/null
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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.
+ *
+ * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
+ * - enable working with Layer 3 protocol independent connection tracking.
+ *
+ * Derived from net/ipv4/netfilter/ip_conntrack_proto_icmp.c
+ */
+
+#include <linux/types.h>
+#include <linux/sched.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_protocol.h>
+#include <net/netfilter/nf_conntrack_core.h>
+
+unsigned long nf_ct_icmp_timeout = 30*HZ;
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static int icmp_pkt_to_tuple(const struct sk_buff *skb,
+ unsigned int dataoff,
+ struct nf_conntrack_tuple *tuple)
+{
+ struct icmphdr _hdr, *hp;
+
+ hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
+ if (hp == NULL)
+ return 0;
+
+ tuple->dst.u.icmp.type = hp->type;
+ tuple->src.u.icmp.id = hp->un.echo.id;
+ tuple->dst.u.icmp.code = hp->code;
+
+ return 1;
+}
+
+/* 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 int 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 0;
+
+ 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 1;
+}
+
+/* Print out the per-protocol part of the tuple. */
+static int icmp_print_tuple(struct seq_file *s,
+ const struct nf_conntrack_tuple *tuple)
+{
+ return 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));
+}
+
+/* Print out the private part of the conntrack. */
+static int icmp_print_conntrack(struct seq_file *s,
+ const struct nf_conn *conntrack)
+{
+ return 0;
+}
+
+/* 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,
+ int pf,
+ unsigned int hooknum)
+{
+ /* Try to delete connection immediately after all replies:
+ won't actually vanish as we still have skb, and del_timer
+ means this will only run once even if count hits zero twice
+ (theoretically possible with SMP) */
+ if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
+ if (atomic_dec_and_test(&ct->proto.icmp.count)
+ && del_timer(&ct->timeout))
+ ct->timeout.function((unsigned long)ct);
+ } else {
+ atomic_inc(&ct->proto.icmp.count);
+ nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
+ nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmp_timeout);
+ }
+
+ return NF_ACCEPT;
+}
+
+/* Called when a new connection for this protocol found. */
+static int icmp_new(struct nf_conn *conntrack,
+ const struct sk_buff *skb, unsigned int dataoff)
+{
+ static const u_int8_t valid_new[] = {
+ [ICMP_ECHO] = 1,
+ [ICMP_TIMESTAMP] = 1,
+ [ICMP_INFO_REQUEST] = 1,
+ [ICMP_ADDRESS] = 1
+ };
+
+ if (conntrack->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new)
+ || !valid_new[conntrack->tuplehash[0].tuple.dst.u.icmp.type]) {
+ /* Can't create a new ICMP `conn' with this. */
+ DEBUGP("icmp: can't create new conn with type %u\n",
+ conntrack->tuplehash[0].tuple.dst.u.icmp.type);
+ NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
+ return 0;
+ }
+ atomic_set(&conntrack->proto.icmp.count, 0);
+ return 1;
+}
+
+extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
+/* Returns conntrack if it dealt with ICMP, and filled in skb fields */
+static int
+icmp_error_message(struct sk_buff *skb,
+ enum ip_conntrack_info *ctinfo,
+ unsigned int hooknum)
+{
+ struct nf_conntrack_tuple innertuple, origtuple;
+ struct {
+ struct icmphdr icmp;
+ struct iphdr ip;
+ } _in, *inside;
+ struct nf_conntrack_protocol *innerproto;
+ struct nf_conntrack_tuple_hash *h;
+ int dataoff;
+
+ NF_CT_ASSERT(skb->nfct == NULL);
+
+ /* Not enough header? */
+ inside = skb_header_pointer(skb, skb->nh.iph->ihl*4, sizeof(_in), &_in);
+ if (inside == NULL)
+ return -NF_ACCEPT;
+
+ /* Ignore ICMP's containing fragments (shouldn't happen) */
+ if (inside->ip.frag_off & htons(IP_OFFSET)) {
+ DEBUGP("icmp_error_message: fragment of proto %u\n",
+ inside->ip.protocol);
+ return -NF_ACCEPT;
+ }
+
+ innerproto = __nf_ct_proto_find(PF_INET, inside->ip.protocol);
+ dataoff = skb->nh.iph->ihl*4 + sizeof(inside->icmp);
+ /* Are they talking about one of our connections? */
+ if (!nf_ct_get_tuple(skb, dataoff, dataoff + inside->ip.ihl*4, PF_INET,
+ inside->ip.protocol, &origtuple,
+ &nf_conntrack_l3proto_ipv4, innerproto)) {
+ DEBUGP("icmp_error_message: ! get_tuple p=%u",
+ inside->ip.protocol);
+ return -NF_ACCEPT;
+ }
+
+ /* 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)) {
+ DEBUGP("icmp_error_message: no match\n");
+ return -NF_ACCEPT;
+ }
+
+ *ctinfo = IP_CT_RELATED;
+
+ h = nf_conntrack_find_get(&innertuple, NULL);
+ if (!h) {
+ /* Locally generated ICMPs will match inverted if they
+ haven't been SNAT'ed yet */
+ /* FIXME: NAT code has to handle half-done double NAT --RR */
+ if (hooknum == NF_IP_LOCAL_OUT)
+ h = nf_conntrack_find_get(&origtuple, NULL);
+
+ if (!h) {
+ DEBUGP("icmp_error_message: no match\n");
+ return -NF_ACCEPT;
+ }
+
+ /* Reverse direction from that found */
+ if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
+ *ctinfo += IP_CT_IS_REPLY;
+ } else {
+ 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 sk_buff *skb, unsigned int dataoff,
+ enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
+{
+ struct icmphdr _ih, *icmph;
+
+ /* Not enough header? */
+ icmph = skb_header_pointer(skb, skb->nh.iph->ihl*4, sizeof(_ih), &_ih);
+ if (icmph == NULL) {
+ if (LOG_INVALID(IPPROTO_ICMP))
+ nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
+ "nf_ct_icmp: short packet ");
+ return -NF_ACCEPT;
+ }
+
+ /* See ip_conntrack_proto_tcp.c */
+ if (hooknum == NF_IP_PRE_ROUTING &&
+ nf_ip_checksum(skb, hooknum, dataoff, 0)) {
+ if (LOG_INVALID(IPPROTO_ICMP))
+ nf_log_packet(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(IPPROTO_ICMP))
+ nf_log_packet(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(skb, ctinfo, hooknum);
+}
+
+#if defined(CONFIG_NF_CT_NETLINK) || \
+ defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int icmp_tuple_to_nfattr(struct sk_buff *skb,
+ const struct nf_conntrack_tuple *t)
+{
+ NFA_PUT(skb, CTA_PROTO_ICMP_ID, sizeof(u_int16_t),
+ &t->src.u.icmp.id);
+ NFA_PUT(skb, CTA_PROTO_ICMP_TYPE, sizeof(u_int8_t),
+ &t->dst.u.icmp.type);
+ NFA_PUT(skb, CTA_PROTO_ICMP_CODE, sizeof(u_int8_t),
+ &t->dst.u.icmp.code);
+
+ return 0;
+
+nfattr_failure:
+ return -1;
+}
+
+static const size_t cta_min_proto[CTA_PROTO_MAX] = {
+ [CTA_PROTO_ICMP_TYPE-1] = sizeof(u_int8_t),
+ [CTA_PROTO_ICMP_CODE-1] = sizeof(u_int8_t),
+ [CTA_PROTO_ICMP_ID-1] = sizeof(u_int16_t)
+};
+
+static int icmp_nfattr_to_tuple(struct nfattr *tb[],
+ struct nf_conntrack_tuple *tuple)
+{
+ if (!tb[CTA_PROTO_ICMP_TYPE-1]
+ || !tb[CTA_PROTO_ICMP_CODE-1]
+ || !tb[CTA_PROTO_ICMP_ID-1])
+ return -EINVAL;
+
+ if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
+ return -EINVAL;
+
+ tuple->dst.u.icmp.type =
+ *(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMP_TYPE-1]);
+ tuple->dst.u.icmp.code =
+ *(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMP_CODE-1]);
+ tuple->src.u.icmp.id =
+ *(u_int16_t *)NFA_DATA(tb[CTA_PROTO_ICMP_ID-1]);
+
+ if (tuple->dst.u.icmp.type >= sizeof(invmap)
+ || !invmap[tuple->dst.u.icmp.type])
+ return -EINVAL;
+
+ return 0;
+}
+#endif
+
+struct nf_conntrack_protocol nf_conntrack_protocol_icmp =
+{
+ .list = { NULL, NULL },
+ .l3proto = PF_INET,
+ .proto = IPPROTO_ICMP,
+ .name = "icmp",
+ .pkt_to_tuple = icmp_pkt_to_tuple,
+ .invert_tuple = icmp_invert_tuple,
+ .print_tuple = icmp_print_tuple,
+ .print_conntrack = icmp_print_conntrack,
+ .packet = icmp_packet,
+ .new = icmp_new,
+ .error = icmp_error,
+ .destroy = NULL,
+ .me = NULL,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+ defined(CONFIG_NF_CT_NETLINK_MODULE)
+ .tuple_to_nfattr = icmp_tuple_to_nfattr,
+ .nfattr_to_tuple = icmp_nfattr_to_tuple,
+#endif
+};
+
+EXPORT_SYMBOL(nf_conntrack_protocol_icmp);
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