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-rw-r--r--include/linux/netfilter_ipv6/ip6t_REJECT.h18
-rw-r--r--net/ipv6/netfilter/Kconfig10
-rw-r--r--net/ipv6/netfilter/Makefile1
-rw-r--r--net/ipv6/netfilter/ip6t_REJECT.c284
4 files changed, 313 insertions, 0 deletions
diff --git a/include/linux/netfilter_ipv6/ip6t_REJECT.h b/include/linux/netfilter_ipv6/ip6t_REJECT.h
new file mode 100644
index 000000000000..6be6504162bb
--- /dev/null
+++ b/include/linux/netfilter_ipv6/ip6t_REJECT.h
@@ -0,0 +1,18 @@
1#ifndef _IP6T_REJECT_H
2#define _IP6T_REJECT_H
3
4enum ip6t_reject_with {
5 IP6T_ICMP6_NO_ROUTE,
6 IP6T_ICMP6_ADM_PROHIBITED,
7 IP6T_ICMP6_NOT_NEIGHBOUR,
8 IP6T_ICMP6_ADDR_UNREACH,
9 IP6T_ICMP6_PORT_UNREACH,
10 IP6T_ICMP6_ECHOREPLY,
11 IP6T_TCP_RESET
12};
13
14struct ip6t_reject_info {
15 u_int32_t with; /* reject type */
16};
17
18#endif /*_IP6T_REJECT_H*/
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index cd1551983c63..8a10c2d0d154 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -199,6 +199,16 @@ config IP6_NF_TARGET_LOG
199 199
200 To compile it as a module, choose M here. If unsure, say N. 200 To compile it as a module, choose M here. If unsure, say N.
201 201
202config IP6_NF_TARGET_REJECT
203 tristate "REJECT target support"
204 depends on IP6_NF_FILTER
205 help
206 The REJECT target allows a filtering rule to specify that an ICMPv6
207 error should be issued in response to an incoming packet, rather
208 than silently being dropped.
209
210 To compile it as a module, choose M here. If unsure, say N.
211
202# if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then 212# if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then
203# dep_tristate ' REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER 213# dep_tristate ' REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER
204# if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then 214# if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index 847651dbcd2a..70f6ba610102 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -24,4 +24,5 @@ obj-$(CONFIG_IP6_NF_QUEUE) += ip6_queue.o
24obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o 24obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o
25obj-$(CONFIG_IP6_NF_RAW) += ip6table_raw.o 25obj-$(CONFIG_IP6_NF_RAW) += ip6table_raw.o
26obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o 26obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o
27obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
27obj-$(CONFIG_NETFILTER_NETLINK_QUEUE) += ip6t_NFQUEUE.o 28obj-$(CONFIG_NETFILTER_NETLINK_QUEUE) += ip6t_NFQUEUE.o
diff --git a/net/ipv6/netfilter/ip6t_REJECT.c b/net/ipv6/netfilter/ip6t_REJECT.c
new file mode 100644
index 000000000000..14316c3ebde4
--- /dev/null
+++ b/net/ipv6/netfilter/ip6t_REJECT.c
@@ -0,0 +1,284 @@
1/*
2 * IP6 tables REJECT target module
3 * Linux INET6 implementation
4 *
5 * Copyright (C)2003 USAGI/WIDE Project
6 *
7 * Authors:
8 * Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
9 *
10 * Based on net/ipv4/netfilter/ipt_REJECT.c
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18#include <linux/config.h>
19#include <linux/module.h>
20#include <linux/skbuff.h>
21#include <linux/icmpv6.h>
22#include <linux/netdevice.h>
23#include <net/ipv6.h>
24#include <net/tcp.h>
25#include <net/icmp.h>
26#include <net/ip6_checksum.h>
27#include <net/ip6_fib.h>
28#include <net/ip6_route.h>
29#include <net/flow.h>
30#include <linux/netfilter_ipv6/ip6_tables.h>
31#include <linux/netfilter_ipv6/ip6t_REJECT.h>
32
33MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
34MODULE_DESCRIPTION("IP6 tables REJECT target module");
35MODULE_LICENSE("GPL");
36
37#if 0
38#define DEBUGP printk
39#else
40#define DEBUGP(format, args...)
41#endif
42
43/* Send RST reply */
44static void send_reset(struct sk_buff *oldskb)
45{
46 struct sk_buff *nskb;
47 struct tcphdr otcph, *tcph;
48 unsigned int otcplen, hh_len;
49 int tcphoff, needs_ack;
50 struct ipv6hdr *oip6h = oldskb->nh.ipv6h, *ip6h;
51 struct dst_entry *dst = NULL;
52 u8 proto;
53 struct flowi fl;
54
55 if ((!(ipv6_addr_type(&oip6h->saddr) & IPV6_ADDR_UNICAST)) ||
56 (!(ipv6_addr_type(&oip6h->daddr) & IPV6_ADDR_UNICAST))) {
57 DEBUGP("ip6t_REJECT: addr is not unicast.\n");
58 return;
59 }
60
61 proto = oip6h->nexthdr;
62 tcphoff = ipv6_skip_exthdr(oldskb, ((u8*)(oip6h+1) - oldskb->data), &proto);
63
64 if ((tcphoff < 0) || (tcphoff > oldskb->len)) {
65 DEBUGP("ip6t_REJECT: Can't get TCP header.\n");
66 return;
67 }
68
69 otcplen = oldskb->len - tcphoff;
70
71 /* IP header checks: fragment, too short. */
72 if ((proto != IPPROTO_TCP) || (otcplen < sizeof(struct tcphdr))) {
73 DEBUGP("ip6t_REJECT: proto(%d) != IPPROTO_TCP, or too short. otcplen = %d\n",
74 proto, otcplen);
75 return;
76 }
77
78 if (skb_copy_bits(oldskb, tcphoff, &otcph, sizeof(struct tcphdr)))
79 BUG();
80
81 /* No RST for RST. */
82 if (otcph.rst) {
83 DEBUGP("ip6t_REJECT: RST is set\n");
84 return;
85 }
86
87 /* Check checksum. */
88 if (csum_ipv6_magic(&oip6h->saddr, &oip6h->daddr, otcplen, IPPROTO_TCP,
89 skb_checksum(oldskb, tcphoff, otcplen, 0))) {
90 DEBUGP("ip6t_REJECT: TCP checksum is invalid\n");
91 return;
92 }
93
94 memset(&fl, 0, sizeof(fl));
95 fl.proto = IPPROTO_TCP;
96 ipv6_addr_copy(&fl.fl6_src, &oip6h->daddr);
97 ipv6_addr_copy(&fl.fl6_dst, &oip6h->saddr);
98 fl.fl_ip_sport = otcph.dest;
99 fl.fl_ip_dport = otcph.source;
100 dst = ip6_route_output(NULL, &fl);
101 if (dst == NULL)
102 return;
103 if (dst->error ||
104 xfrm_lookup(&dst, &fl, NULL, 0)) {
105 dst_release(dst);
106 return;
107 }
108
109 hh_len = (dst->dev->hard_header_len + 15)&~15;
110 nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
111 + sizeof(struct tcphdr) + dst->trailer_len,
112 GFP_ATOMIC);
113
114 if (!nskb) {
115 if (net_ratelimit())
116 printk("ip6t_REJECT: Can't alloc skb\n");
117 dst_release(dst);
118 return;
119 }
120
121 nskb->dst = dst;
122
123 skb_reserve(nskb, hh_len + dst->header_len);
124
125 ip6h = nskb->nh.ipv6h = (struct ipv6hdr *)
126 skb_put(nskb, sizeof(struct ipv6hdr));
127 ip6h->version = 6;
128 ip6h->hop_limit = dst_metric(dst, RTAX_HOPLIMIT);
129 ip6h->nexthdr = IPPROTO_TCP;
130 ip6h->payload_len = htons(sizeof(struct tcphdr));
131 ipv6_addr_copy(&ip6h->saddr, &oip6h->daddr);
132 ipv6_addr_copy(&ip6h->daddr, &oip6h->saddr);
133
134 tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
135 /* Truncate to length (no data) */
136 tcph->doff = sizeof(struct tcphdr)/4;
137 tcph->source = otcph.dest;
138 tcph->dest = otcph.source;
139
140 if (otcph.ack) {
141 needs_ack = 0;
142 tcph->seq = otcph.ack_seq;
143 tcph->ack_seq = 0;
144 } else {
145 needs_ack = 1;
146 tcph->ack_seq = htonl(ntohl(otcph.seq) + otcph.syn + otcph.fin
147 + otcplen - (otcph.doff<<2));
148 tcph->seq = 0;
149 }
150
151 /* Reset flags */
152 ((u_int8_t *)tcph)[13] = 0;
153 tcph->rst = 1;
154 tcph->ack = needs_ack;
155 tcph->window = 0;
156 tcph->urg_ptr = 0;
157 tcph->check = 0;
158
159 /* Adjust TCP checksum */
160 tcph->check = csum_ipv6_magic(&nskb->nh.ipv6h->saddr,
161 &nskb->nh.ipv6h->daddr,
162 sizeof(struct tcphdr), IPPROTO_TCP,
163 csum_partial((char *)tcph,
164 sizeof(struct tcphdr), 0));
165
166 NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
167 dst_output);
168}
169
170static inline void
171send_unreach(struct sk_buff *skb_in, unsigned char code, unsigned int hooknum)
172{
173 if (hooknum == NF_IP6_LOCAL_OUT && skb_in->dev == NULL)
174 skb_in->dev = &loopback_dev;
175
176 icmpv6_send(skb_in, ICMPV6_DEST_UNREACH, code, 0, NULL);
177}
178
179static unsigned int reject6_target(struct sk_buff **pskb,
180 const struct net_device *in,
181 const struct net_device *out,
182 unsigned int hooknum,
183 const void *targinfo,
184 void *userinfo)
185{
186 const struct ip6t_reject_info *reject = targinfo;
187
188 DEBUGP(KERN_DEBUG "%s: medium point\n", __FUNCTION__);
189 /* WARNING: This code causes reentry within ip6tables.
190 This means that the ip6tables jump stack is now crap. We
191 must return an absolute verdict. --RR */
192 switch (reject->with) {
193 case IP6T_ICMP6_NO_ROUTE:
194 send_unreach(*pskb, ICMPV6_NOROUTE, hooknum);
195 break;
196 case IP6T_ICMP6_ADM_PROHIBITED:
197 send_unreach(*pskb, ICMPV6_ADM_PROHIBITED, hooknum);
198 break;
199 case IP6T_ICMP6_NOT_NEIGHBOUR:
200 send_unreach(*pskb, ICMPV6_NOT_NEIGHBOUR, hooknum);
201 break;
202 case IP6T_ICMP6_ADDR_UNREACH:
203 send_unreach(*pskb, ICMPV6_ADDR_UNREACH, hooknum);
204 break;
205 case IP6T_ICMP6_PORT_UNREACH:
206 send_unreach(*pskb, ICMPV6_PORT_UNREACH, hooknum);
207 break;
208 case IP6T_ICMP6_ECHOREPLY:
209 /* Do nothing */
210 break;
211 case IP6T_TCP_RESET:
212 send_reset(*pskb);
213 break;
214 default:
215 if (net_ratelimit())
216 printk(KERN_WARNING "ip6t_REJECT: case %u not handled yet\n", reject->with);
217 break;
218 }
219
220 return NF_DROP;
221}
222
223static int check(const char *tablename,
224 const struct ip6t_entry *e,
225 void *targinfo,
226 unsigned int targinfosize,
227 unsigned int hook_mask)
228{
229 const struct ip6t_reject_info *rejinfo = targinfo;
230
231 if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_reject_info))) {
232 DEBUGP("ip6t_REJECT: targinfosize %u != 0\n", targinfosize);
233 return 0;
234 }
235
236 /* Only allow these for packet filtering. */
237 if (strcmp(tablename, "filter") != 0) {
238 DEBUGP("ip6t_REJECT: bad table `%s'.\n", tablename);
239 return 0;
240 }
241
242 if ((hook_mask & ~((1 << NF_IP6_LOCAL_IN)
243 | (1 << NF_IP6_FORWARD)
244 | (1 << NF_IP6_LOCAL_OUT))) != 0) {
245 DEBUGP("ip6t_REJECT: bad hook mask %X\n", hook_mask);
246 return 0;
247 }
248
249 if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
250 printk("ip6t_REJECT: ECHOREPLY is not supported.\n");
251 return 0;
252 } else if (rejinfo->with == IP6T_TCP_RESET) {
253 /* Must specify that it's a TCP packet */
254 if (e->ipv6.proto != IPPROTO_TCP
255 || (e->ipv6.invflags & IP6T_INV_PROTO)) {
256 DEBUGP("ip6t_REJECT: TCP_RESET illegal for non-tcp\n");
257 return 0;
258 }
259 }
260
261 return 1;
262}
263
264static struct ip6t_target ip6t_reject_reg = {
265 .name = "REJECT",
266 .target = reject6_target,
267 .checkentry = check,
268 .me = THIS_MODULE
269};
270
271static int __init init(void)
272{
273 if (ip6t_register_target(&ip6t_reject_reg))
274 return -EINVAL;
275 return 0;
276}
277
278static void __exit fini(void)
279{
280 ip6t_unregister_target(&ip6t_reject_reg);
281}
282
283module_init(init);
284module_exit(fini);