| 1 |
3 |
xianfeng |
/* (C) 1999-2001 Paul `Rusty' Russell
|
| 2 |
|
|
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
|
| 3 |
|
|
*
|
| 4 |
|
|
* This program is free software; you can redistribute it and/or modify
|
| 5 |
|
|
* it under the terms of the GNU General Public License version 2 as
|
| 6 |
|
|
* published by the Free Software Foundation.
|
| 7 |
|
|
*/
|
| 8 |
|
|
|
| 9 |
|
|
#include <linux/types.h>
|
| 10 |
|
|
#include <linux/timer.h>
|
| 11 |
|
|
#include <linux/netfilter.h>
|
| 12 |
|
|
#include <linux/in.h>
|
| 13 |
|
|
#include <linux/icmp.h>
|
| 14 |
|
|
#include <linux/seq_file.h>
|
| 15 |
|
|
#include <net/ip.h>
|
| 16 |
|
|
#include <net/checksum.h>
|
| 17 |
|
|
#include <linux/netfilter_ipv4.h>
|
| 18 |
|
|
#include <net/netfilter/nf_conntrack_tuple.h>
|
| 19 |
|
|
#include <net/netfilter/nf_conntrack_l4proto.h>
|
| 20 |
|
|
#include <net/netfilter/nf_conntrack_core.h>
|
| 21 |
|
|
|
| 22 |
|
|
static unsigned long nf_ct_icmp_timeout __read_mostly = 30*HZ;
|
| 23 |
|
|
|
| 24 |
|
|
static int icmp_pkt_to_tuple(const struct sk_buff *skb,
|
| 25 |
|
|
unsigned int dataoff,
|
| 26 |
|
|
struct nf_conntrack_tuple *tuple)
|
| 27 |
|
|
{
|
| 28 |
|
|
struct icmphdr _hdr, *hp;
|
| 29 |
|
|
|
| 30 |
|
|
hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
|
| 31 |
|
|
if (hp == NULL)
|
| 32 |
|
|
return 0;
|
| 33 |
|
|
|
| 34 |
|
|
tuple->dst.u.icmp.type = hp->type;
|
| 35 |
|
|
tuple->src.u.icmp.id = hp->un.echo.id;
|
| 36 |
|
|
tuple->dst.u.icmp.code = hp->code;
|
| 37 |
|
|
|
| 38 |
|
|
return 1;
|
| 39 |
|
|
}
|
| 40 |
|
|
|
| 41 |
|
|
/* Add 1; spaces filled with 0. */
|
| 42 |
|
|
static const u_int8_t invmap[] = {
|
| 43 |
|
|
[ICMP_ECHO] = ICMP_ECHOREPLY + 1,
|
| 44 |
|
|
[ICMP_ECHOREPLY] = ICMP_ECHO + 1,
|
| 45 |
|
|
[ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
|
| 46 |
|
|
[ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
|
| 47 |
|
|
[ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
|
| 48 |
|
|
[ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
|
| 49 |
|
|
[ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
|
| 50 |
|
|
[ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1
|
| 51 |
|
|
};
|
| 52 |
|
|
|
| 53 |
|
|
static int icmp_invert_tuple(struct nf_conntrack_tuple *tuple,
|
| 54 |
|
|
const struct nf_conntrack_tuple *orig)
|
| 55 |
|
|
{
|
| 56 |
|
|
if (orig->dst.u.icmp.type >= sizeof(invmap)
|
| 57 |
|
|
|| !invmap[orig->dst.u.icmp.type])
|
| 58 |
|
|
return 0;
|
| 59 |
|
|
|
| 60 |
|
|
tuple->src.u.icmp.id = orig->src.u.icmp.id;
|
| 61 |
|
|
tuple->dst.u.icmp.type = invmap[orig->dst.u.icmp.type] - 1;
|
| 62 |
|
|
tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
|
| 63 |
|
|
return 1;
|
| 64 |
|
|
}
|
| 65 |
|
|
|
| 66 |
|
|
/* Print out the per-protocol part of the tuple. */
|
| 67 |
|
|
static int icmp_print_tuple(struct seq_file *s,
|
| 68 |
|
|
const struct nf_conntrack_tuple *tuple)
|
| 69 |
|
|
{
|
| 70 |
|
|
return seq_printf(s, "type=%u code=%u id=%u ",
|
| 71 |
|
|
tuple->dst.u.icmp.type,
|
| 72 |
|
|
tuple->dst.u.icmp.code,
|
| 73 |
|
|
ntohs(tuple->src.u.icmp.id));
|
| 74 |
|
|
}
|
| 75 |
|
|
|
| 76 |
|
|
/* Print out the private part of the conntrack. */
|
| 77 |
|
|
static int icmp_print_conntrack(struct seq_file *s,
|
| 78 |
|
|
const struct nf_conn *conntrack)
|
| 79 |
|
|
{
|
| 80 |
|
|
return 0;
|
| 81 |
|
|
}
|
| 82 |
|
|
|
| 83 |
|
|
/* Returns verdict for packet, or -1 for invalid. */
|
| 84 |
|
|
static int icmp_packet(struct nf_conn *ct,
|
| 85 |
|
|
const struct sk_buff *skb,
|
| 86 |
|
|
unsigned int dataoff,
|
| 87 |
|
|
enum ip_conntrack_info ctinfo,
|
| 88 |
|
|
int pf,
|
| 89 |
|
|
unsigned int hooknum)
|
| 90 |
|
|
{
|
| 91 |
|
|
/* Try to delete connection immediately after all replies:
|
| 92 |
|
|
won't actually vanish as we still have skb, and del_timer
|
| 93 |
|
|
means this will only run once even if count hits zero twice
|
| 94 |
|
|
(theoretically possible with SMP) */
|
| 95 |
|
|
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
|
| 96 |
|
|
if (atomic_dec_and_test(&ct->proto.icmp.count)
|
| 97 |
|
|
&& del_timer(&ct->timeout))
|
| 98 |
|
|
ct->timeout.function((unsigned long)ct);
|
| 99 |
|
|
} else {
|
| 100 |
|
|
atomic_inc(&ct->proto.icmp.count);
|
| 101 |
|
|
nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
|
| 102 |
|
|
nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmp_timeout);
|
| 103 |
|
|
}
|
| 104 |
|
|
|
| 105 |
|
|
return NF_ACCEPT;
|
| 106 |
|
|
}
|
| 107 |
|
|
|
| 108 |
|
|
/* Called when a new connection for this protocol found. */
|
| 109 |
|
|
static int icmp_new(struct nf_conn *conntrack,
|
| 110 |
|
|
const struct sk_buff *skb, unsigned int dataoff)
|
| 111 |
|
|
{
|
| 112 |
|
|
static const u_int8_t valid_new[] = {
|
| 113 |
|
|
[ICMP_ECHO] = 1,
|
| 114 |
|
|
[ICMP_TIMESTAMP] = 1,
|
| 115 |
|
|
[ICMP_INFO_REQUEST] = 1,
|
| 116 |
|
|
[ICMP_ADDRESS] = 1
|
| 117 |
|
|
};
|
| 118 |
|
|
|
| 119 |
|
|
if (conntrack->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new)
|
| 120 |
|
|
|| !valid_new[conntrack->tuplehash[0].tuple.dst.u.icmp.type]) {
|
| 121 |
|
|
/* Can't create a new ICMP `conn' with this. */
|
| 122 |
|
|
pr_debug("icmp: can't create new conn with type %u\n",
|
| 123 |
|
|
conntrack->tuplehash[0].tuple.dst.u.icmp.type);
|
| 124 |
|
|
NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
|
| 125 |
|
|
return 0;
|
| 126 |
|
|
}
|
| 127 |
|
|
atomic_set(&conntrack->proto.icmp.count, 0);
|
| 128 |
|
|
return 1;
|
| 129 |
|
|
}
|
| 130 |
|
|
|
| 131 |
|
|
extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
|
| 132 |
|
|
/* Returns conntrack if it dealt with ICMP, and filled in skb fields */
|
| 133 |
|
|
static int
|
| 134 |
|
|
icmp_error_message(struct sk_buff *skb,
|
| 135 |
|
|
enum ip_conntrack_info *ctinfo,
|
| 136 |
|
|
unsigned int hooknum)
|
| 137 |
|
|
{
|
| 138 |
|
|
struct nf_conntrack_tuple innertuple, origtuple;
|
| 139 |
|
|
struct nf_conntrack_l4proto *innerproto;
|
| 140 |
|
|
struct nf_conntrack_tuple_hash *h;
|
| 141 |
|
|
|
| 142 |
|
|
NF_CT_ASSERT(skb->nfct == NULL);
|
| 143 |
|
|
|
| 144 |
|
|
/* Are they talking about one of our connections? */
|
| 145 |
|
|
if (!nf_ct_get_tuplepr(skb,
|
| 146 |
|
|
skb_network_offset(skb) + ip_hdrlen(skb)
|
| 147 |
|
|
+ sizeof(struct icmphdr),
|
| 148 |
|
|
PF_INET, &origtuple)) {
|
| 149 |
|
|
pr_debug("icmp_error_message: failed to get tuple\n");
|
| 150 |
|
|
return -NF_ACCEPT;
|
| 151 |
|
|
}
|
| 152 |
|
|
|
| 153 |
|
|
/* rcu_read_lock()ed by nf_hook_slow */
|
| 154 |
|
|
innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum);
|
| 155 |
|
|
|
| 156 |
|
|
/* Ordinarily, we'd expect the inverted tupleproto, but it's
|
| 157 |
|
|
been preserved inside the ICMP. */
|
| 158 |
|
|
if (!nf_ct_invert_tuple(&innertuple, &origtuple,
|
| 159 |
|
|
&nf_conntrack_l3proto_ipv4, innerproto)) {
|
| 160 |
|
|
pr_debug("icmp_error_message: no match\n");
|
| 161 |
|
|
return -NF_ACCEPT;
|
| 162 |
|
|
}
|
| 163 |
|
|
|
| 164 |
|
|
*ctinfo = IP_CT_RELATED;
|
| 165 |
|
|
|
| 166 |
|
|
h = nf_conntrack_find_get(&innertuple);
|
| 167 |
|
|
if (!h) {
|
| 168 |
|
|
pr_debug("icmp_error_message: no match\n");
|
| 169 |
|
|
return -NF_ACCEPT;
|
| 170 |
|
|
}
|
| 171 |
|
|
|
| 172 |
|
|
if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
|
| 173 |
|
|
*ctinfo += IP_CT_IS_REPLY;
|
| 174 |
|
|
|
| 175 |
|
|
/* Update skb to refer to this connection */
|
| 176 |
|
|
skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
|
| 177 |
|
|
skb->nfctinfo = *ctinfo;
|
| 178 |
|
|
return -NF_ACCEPT;
|
| 179 |
|
|
}
|
| 180 |
|
|
|
| 181 |
|
|
/* Small and modified version of icmp_rcv */
|
| 182 |
|
|
static int
|
| 183 |
|
|
icmp_error(struct sk_buff *skb, unsigned int dataoff,
|
| 184 |
|
|
enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
|
| 185 |
|
|
{
|
| 186 |
|
|
struct icmphdr _ih, *icmph;
|
| 187 |
|
|
|
| 188 |
|
|
/* Not enough header? */
|
| 189 |
|
|
icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih);
|
| 190 |
|
|
if (icmph == NULL) {
|
| 191 |
|
|
if (LOG_INVALID(IPPROTO_ICMP))
|
| 192 |
|
|
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
|
| 193 |
|
|
"nf_ct_icmp: short packet ");
|
| 194 |
|
|
return -NF_ACCEPT;
|
| 195 |
|
|
}
|
| 196 |
|
|
|
| 197 |
|
|
/* See ip_conntrack_proto_tcp.c */
|
| 198 |
|
|
if (nf_conntrack_checksum && hooknum == NF_IP_PRE_ROUTING &&
|
| 199 |
|
|
nf_ip_checksum(skb, hooknum, dataoff, 0)) {
|
| 200 |
|
|
if (LOG_INVALID(IPPROTO_ICMP))
|
| 201 |
|
|
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
|
| 202 |
|
|
"nf_ct_icmp: bad HW ICMP checksum ");
|
| 203 |
|
|
return -NF_ACCEPT;
|
| 204 |
|
|
}
|
| 205 |
|
|
|
| 206 |
|
|
/*
|
| 207 |
|
|
* 18 is the highest 'known' ICMP type. Anything else is a mystery
|
| 208 |
|
|
*
|
| 209 |
|
|
* RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
|
| 210 |
|
|
* discarded.
|
| 211 |
|
|
*/
|
| 212 |
|
|
if (icmph->type > NR_ICMP_TYPES) {
|
| 213 |
|
|
if (LOG_INVALID(IPPROTO_ICMP))
|
| 214 |
|
|
nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
|
| 215 |
|
|
"nf_ct_icmp: invalid ICMP type ");
|
| 216 |
|
|
return -NF_ACCEPT;
|
| 217 |
|
|
}
|
| 218 |
|
|
|
| 219 |
|
|
/* Need to track icmp error message? */
|
| 220 |
|
|
if (icmph->type != ICMP_DEST_UNREACH
|
| 221 |
|
|
&& icmph->type != ICMP_SOURCE_QUENCH
|
| 222 |
|
|
&& icmph->type != ICMP_TIME_EXCEEDED
|
| 223 |
|
|
&& icmph->type != ICMP_PARAMETERPROB
|
| 224 |
|
|
&& icmph->type != ICMP_REDIRECT)
|
| 225 |
|
|
return NF_ACCEPT;
|
| 226 |
|
|
|
| 227 |
|
|
return icmp_error_message(skb, ctinfo, hooknum);
|
| 228 |
|
|
}
|
| 229 |
|
|
|
| 230 |
|
|
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
|
| 231 |
|
|
|
| 232 |
|
|
#include <linux/netfilter/nfnetlink.h>
|
| 233 |
|
|
#include <linux/netfilter/nfnetlink_conntrack.h>
|
| 234 |
|
|
|
| 235 |
|
|
static int icmp_tuple_to_nlattr(struct sk_buff *skb,
|
| 236 |
|
|
const struct nf_conntrack_tuple *t)
|
| 237 |
|
|
{
|
| 238 |
|
|
NLA_PUT(skb, CTA_PROTO_ICMP_ID, sizeof(u_int16_t),
|
| 239 |
|
|
&t->src.u.icmp.id);
|
| 240 |
|
|
NLA_PUT(skb, CTA_PROTO_ICMP_TYPE, sizeof(u_int8_t),
|
| 241 |
|
|
&t->dst.u.icmp.type);
|
| 242 |
|
|
NLA_PUT(skb, CTA_PROTO_ICMP_CODE, sizeof(u_int8_t),
|
| 243 |
|
|
&t->dst.u.icmp.code);
|
| 244 |
|
|
|
| 245 |
|
|
return 0;
|
| 246 |
|
|
|
| 247 |
|
|
nla_put_failure:
|
| 248 |
|
|
return -1;
|
| 249 |
|
|
}
|
| 250 |
|
|
|
| 251 |
|
|
static const struct nla_policy icmp_nla_policy[CTA_PROTO_MAX+1] = {
|
| 252 |
|
|
[CTA_PROTO_ICMP_TYPE] = { .type = NLA_U8 },
|
| 253 |
|
|
[CTA_PROTO_ICMP_CODE] = { .type = NLA_U8 },
|
| 254 |
|
|
[CTA_PROTO_ICMP_ID] = { .type = NLA_U16 },
|
| 255 |
|
|
};
|
| 256 |
|
|
|
| 257 |
|
|
static int icmp_nlattr_to_tuple(struct nlattr *tb[],
|
| 258 |
|
|
struct nf_conntrack_tuple *tuple)
|
| 259 |
|
|
{
|
| 260 |
|
|
if (!tb[CTA_PROTO_ICMP_TYPE]
|
| 261 |
|
|
|| !tb[CTA_PROTO_ICMP_CODE]
|
| 262 |
|
|
|| !tb[CTA_PROTO_ICMP_ID])
|
| 263 |
|
|
return -EINVAL;
|
| 264 |
|
|
|
| 265 |
|
|
tuple->dst.u.icmp.type =
|
| 266 |
|
|
*(u_int8_t *)nla_data(tb[CTA_PROTO_ICMP_TYPE]);
|
| 267 |
|
|
tuple->dst.u.icmp.code =
|
| 268 |
|
|
*(u_int8_t *)nla_data(tb[CTA_PROTO_ICMP_CODE]);
|
| 269 |
|
|
tuple->src.u.icmp.id =
|
| 270 |
|
|
*(__be16 *)nla_data(tb[CTA_PROTO_ICMP_ID]);
|
| 271 |
|
|
|
| 272 |
|
|
if (tuple->dst.u.icmp.type >= sizeof(invmap)
|
| 273 |
|
|
|| !invmap[tuple->dst.u.icmp.type])
|
| 274 |
|
|
return -EINVAL;
|
| 275 |
|
|
|
| 276 |
|
|
return 0;
|
| 277 |
|
|
}
|
| 278 |
|
|
#endif
|
| 279 |
|
|
|
| 280 |
|
|
#ifdef CONFIG_SYSCTL
|
| 281 |
|
|
static struct ctl_table_header *icmp_sysctl_header;
|
| 282 |
|
|
static struct ctl_table icmp_sysctl_table[] = {
|
| 283 |
|
|
{
|
| 284 |
|
|
.procname = "nf_conntrack_icmp_timeout",
|
| 285 |
|
|
.data = &nf_ct_icmp_timeout,
|
| 286 |
|
|
.maxlen = sizeof(unsigned int),
|
| 287 |
|
|
.mode = 0644,
|
| 288 |
|
|
.proc_handler = &proc_dointvec_jiffies,
|
| 289 |
|
|
},
|
| 290 |
|
|
{
|
| 291 |
|
|
.ctl_name = 0
|
| 292 |
|
|
}
|
| 293 |
|
|
};
|
| 294 |
|
|
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
|
| 295 |
|
|
static struct ctl_table icmp_compat_sysctl_table[] = {
|
| 296 |
|
|
{
|
| 297 |
|
|
.procname = "ip_conntrack_icmp_timeout",
|
| 298 |
|
|
.data = &nf_ct_icmp_timeout,
|
| 299 |
|
|
.maxlen = sizeof(unsigned int),
|
| 300 |
|
|
.mode = 0644,
|
| 301 |
|
|
.proc_handler = &proc_dointvec_jiffies,
|
| 302 |
|
|
},
|
| 303 |
|
|
{
|
| 304 |
|
|
.ctl_name = 0
|
| 305 |
|
|
}
|
| 306 |
|
|
};
|
| 307 |
|
|
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
|
| 308 |
|
|
#endif /* CONFIG_SYSCTL */
|
| 309 |
|
|
|
| 310 |
|
|
struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly =
|
| 311 |
|
|
{
|
| 312 |
|
|
.l3proto = PF_INET,
|
| 313 |
|
|
.l4proto = IPPROTO_ICMP,
|
| 314 |
|
|
.name = "icmp",
|
| 315 |
|
|
.pkt_to_tuple = icmp_pkt_to_tuple,
|
| 316 |
|
|
.invert_tuple = icmp_invert_tuple,
|
| 317 |
|
|
.print_tuple = icmp_print_tuple,
|
| 318 |
|
|
.print_conntrack = icmp_print_conntrack,
|
| 319 |
|
|
.packet = icmp_packet,
|
| 320 |
|
|
.new = icmp_new,
|
| 321 |
|
|
.error = icmp_error,
|
| 322 |
|
|
.destroy = NULL,
|
| 323 |
|
|
.me = NULL,
|
| 324 |
|
|
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
|
| 325 |
|
|
.tuple_to_nlattr = icmp_tuple_to_nlattr,
|
| 326 |
|
|
.nlattr_to_tuple = icmp_nlattr_to_tuple,
|
| 327 |
|
|
.nla_policy = icmp_nla_policy,
|
| 328 |
|
|
#endif
|
| 329 |
|
|
#ifdef CONFIG_SYSCTL
|
| 330 |
|
|
.ctl_table_header = &icmp_sysctl_header,
|
| 331 |
|
|
.ctl_table = icmp_sysctl_table,
|
| 332 |
|
|
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
|
| 333 |
|
|
.ctl_compat_table = icmp_compat_sysctl_table,
|
| 334 |
|
|
#endif
|
| 335 |
|
|
#endif
|
| 336 |
|
|
};
|
