[deliverable/linux.git] / net / ipv4 / netfilter / ipt_REJECT.c

/*
 * This is a module which is used for rejecting packets.
 * Added support for customized reject packets (Jozsef Kadlecsik).
 * Added support for ICMP type-3-code-13 (Maciej Soltysiak). [RFC 1812]
 */

/* (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.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/tcp.h>
#include <net/route.h>
#include <net/dst.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_REJECT.h>
#ifdef CONFIG_BRIDGE_NETFILTER
#include <linux/netfilter_bridge.h>
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("iptables REJECT target module");

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

static inline struct rtable *route_reverse(struct sk_buff *skb, 
					   struct tcphdr *tcph, int hook)
{
	struct iphdr *iph = skb->nh.iph;
	struct dst_entry *odst;
	struct flowi fl = {};
	struct rtable *rt;

	/* We don't require ip forwarding to be enabled to be able to
	 * send a RST reply for bridged traffic. */
	if (hook != NF_IP_FORWARD
#ifdef CONFIG_BRIDGE_NETFILTER
	    || (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
#endif
	   ) {
		fl.nl_u.ip4_u.daddr = iph->saddr;
		if (hook == NF_IP_LOCAL_IN)
			fl.nl_u.ip4_u.saddr = iph->daddr;
		fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);

		if (ip_route_output_key(&rt, &fl) != 0)
			return NULL;
	} else {
		/* non-local src, find valid iif to satisfy
		 * rp-filter when calling ip_route_input. */
		fl.nl_u.ip4_u.daddr = iph->daddr;
		if (ip_route_output_key(&rt, &fl) != 0)
			return NULL;

		odst = skb->dst;
		if (ip_route_input(skb, iph->saddr, iph->daddr,
		                   RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
			dst_release(&rt->u.dst);
			return NULL;
		}
		dst_release(&rt->u.dst);
		rt = (struct rtable *)skb->dst;
		skb->dst = odst;

		fl.nl_u.ip4_u.daddr = iph->saddr;
		fl.nl_u.ip4_u.saddr = iph->daddr;
		fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
	}

	if (rt->u.dst.error) {
		dst_release(&rt->u.dst);
		return NULL;
	}

	fl.proto = IPPROTO_TCP;
	fl.fl_ip_sport = tcph->dest;
	fl.fl_ip_dport = tcph->source;

	if (xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0)) {
		dst_release(&rt->u.dst);
		rt = NULL;
	}

	return rt;
}

/* Send RST reply */
static void send_reset(struct sk_buff *oldskb, int hook)
{
	struct sk_buff *nskb;
	struct iphdr *iph = oldskb->nh.iph;
	struct tcphdr _otcph, *oth, *tcph;
	struct rtable *rt;
	u_int16_t tmp_port;
	u_int32_t tmp_addr;
	unsigned int tcplen;
	int needs_ack;
	int hh_len;

	/* IP header checks: fragment. */
	if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
		return;

	oth = skb_header_pointer(oldskb, oldskb->nh.iph->ihl * 4,
				 sizeof(_otcph), &_otcph);
	if (oth == NULL)
 		return;

	/* No RST for RST. */
	if (oth->rst)
		return;

	/* Check checksum */
	tcplen = oldskb->len - iph->ihl * 4;
	if (((hook != NF_IP_LOCAL_IN && oldskb->ip_summed != CHECKSUM_HW) ||
	     (hook == NF_IP_LOCAL_IN &&
	      oldskb->ip_summed != CHECKSUM_UNNECESSARY)) &&
	    csum_tcpudp_magic(iph->saddr, iph->daddr, tcplen, IPPROTO_TCP,
	                      oldskb->ip_summed == CHECKSUM_HW ? oldskb->csum :
	                      skb_checksum(oldskb, iph->ihl * 4, tcplen, 0)))
		return;

	if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
		return;

	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);

	/* We need a linear, writeable skb.  We also need to expand
	   headroom in case hh_len of incoming interface < hh_len of
	   outgoing interface */
	nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
			       GFP_ATOMIC);
	if (!nskb) {
		dst_release(&rt->u.dst);
		return;
	}

	dst_release(nskb->dst);
	nskb->dst = &rt->u.dst;

	/* This packet will not be the same as the other: clear nf fields */
	nf_reset(nskb);
	nskb->nfmark = 0;
#ifdef CONFIG_BRIDGE_NETFILTER
	nf_bridge_put(nskb->nf_bridge);
	nskb->nf_bridge = NULL;
#endif

	tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);

	/* Swap source and dest */
	tmp_addr = nskb->nh.iph->saddr;
	nskb->nh.iph->saddr = nskb->nh.iph->daddr;
	nskb->nh.iph->daddr = tmp_addr;
	tmp_port = tcph->source;
	tcph->source = tcph->dest;
	tcph->dest = tmp_port;

	/* Truncate to length (no data) */
	tcph->doff = sizeof(struct tcphdr)/4;
	skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
	nskb->nh.iph->tot_len = htons(nskb->len);

	if (tcph->ack) {
		needs_ack = 0;
		tcph->seq = oth->ack_seq;
		tcph->ack_seq = 0;
	} else {
		needs_ack = 1;
		tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin
				      + oldskb->len - oldskb->nh.iph->ihl*4
				      - (oth->doff<<2));
		tcph->seq = 0;
	}

	/* Reset flags */
	((u_int8_t *)tcph)[13] = 0;
	tcph->rst = 1;
	tcph->ack = needs_ack;

	tcph->window = 0;
	tcph->urg_ptr = 0;

	/* Adjust TCP checksum */
	tcph->check = 0;
	tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
				   nskb->nh.iph->saddr,
				   nskb->nh.iph->daddr,
				   csum_partial((char *)tcph,
						sizeof(struct tcphdr), 0));

	/* Adjust IP TTL, DF */
	nskb->nh.iph->ttl = MAXTTL;
	/* Set DF, id = 0 */
	nskb->nh.iph->frag_off = htons(IP_DF);
	nskb->nh.iph->id = 0;

	/* Adjust IP checksum */
	nskb->nh.iph->check = 0;
	nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph, 
					   nskb->nh.iph->ihl);

	/* "Never happens" */
	if (nskb->len > dst_mtu(nskb->dst))
		goto free_nskb;

	nf_ct_attach(nskb, oldskb);

	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
		dst_output);
	return;

 free_nskb:
	kfree_skb(nskb);
}

static inline void send_unreach(struct sk_buff *skb_in, int code)
{
	icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0);
}	

static unsigned int reject(struct sk_buff **pskb,
			   const struct net_device *in,
			   const struct net_device *out,
			   unsigned int hooknum,
			   const void *targinfo,
			   void *userinfo)
{
	const struct ipt_reject_info *reject = targinfo;

	/* Our naive response construction doesn't deal with IP
           options, and probably shouldn't try. */
	if ((*pskb)->nh.iph->ihl<<2 != sizeof(struct iphdr))
		return NF_DROP;

	/* WARNING: This code causes reentry within iptables.
	   This means that the iptables jump stack is now crap.  We
	   must return an absolute verdict. --RR */
    	switch (reject->with) {
    	case IPT_ICMP_NET_UNREACHABLE:
    		send_unreach(*pskb, ICMP_NET_UNREACH);
    		break;
    	case IPT_ICMP_HOST_UNREACHABLE:
    		send_unreach(*pskb, ICMP_HOST_UNREACH);
    		break;
    	case IPT_ICMP_PROT_UNREACHABLE:
    		send_unreach(*pskb, ICMP_PROT_UNREACH);
    		break;
    	case IPT_ICMP_PORT_UNREACHABLE:
    		send_unreach(*pskb, ICMP_PORT_UNREACH);
    		break;
    	case IPT_ICMP_NET_PROHIBITED:
    		send_unreach(*pskb, ICMP_NET_ANO);
    		break;
	case IPT_ICMP_HOST_PROHIBITED:
    		send_unreach(*pskb, ICMP_HOST_ANO);
    		break;
    	case IPT_ICMP_ADMIN_PROHIBITED:
		send_unreach(*pskb, ICMP_PKT_FILTERED);
		break;
	case IPT_TCP_RESET:
		send_reset(*pskb, hooknum);
	case IPT_ICMP_ECHOREPLY:
		/* Doesn't happen. */
		break;
	}

	return NF_DROP;
}

static int check(const char *tablename,
		 const struct ipt_entry *e,
		 void *targinfo,
		 unsigned int targinfosize,
		 unsigned int hook_mask)
{
 	const struct ipt_reject_info *rejinfo = targinfo;

 	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_reject_info))) {
  		DEBUGP("REJECT: targinfosize %u != 0\n", targinfosize);
  		return 0;
  	}

	/* Only allow these for packet filtering. */
	if (strcmp(tablename, "filter") != 0) {
		DEBUGP("REJECT: bad table `%s'.\n", tablename);
		return 0;
	}
	if ((hook_mask & ~((1 << NF_IP_LOCAL_IN)
			   | (1 << NF_IP_FORWARD)
			   | (1 << NF_IP_LOCAL_OUT))) != 0) {
		DEBUGP("REJECT: bad hook mask %X\n", hook_mask);
		return 0;
	}

	if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
		printk("REJECT: ECHOREPLY no longer supported.\n");
		return 0;
	} else if (rejinfo->with == IPT_TCP_RESET) {
		/* Must specify that it's a TCP packet */
		if (e->ip.proto != IPPROTO_TCP
		    || (e->ip.invflags & IPT_INV_PROTO)) {
			DEBUGP("REJECT: TCP_RESET invalid for non-tcp\n");
			return 0;
		}
	}

	return 1;
}

static struct ipt_target ipt_reject_reg = {
	.name		= "REJECT",
	.target		= reject,
	.checkentry	= check,
	.me		= THIS_MODULE,
};

static int __init init(void)
{
	return ipt_register_target(&ipt_reject_reg);
}

static void __exit fini(void)
{
	ipt_unregister_target(&ipt_reject_reg);
}

module_init(init);
module_exit(fini);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This is a module which is used for rejecting packets.
	3	* Added support for customized reject packets (Jozsef Kadlecsik).
	4	* Added support for ICMP type-3-code-13 (Maciej Soltysiak). [RFC 1812]
	5	*/
	6
	7	/* (C) 1999-2001 Paul `Rusty' Russell
	8	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2 as
	12	* published by the Free Software Foundation.
	13	*/
	14
	15	#include <linux/config.h>
	16	#include <linux/module.h>
	17	#include <linux/skbuff.h>
	18	#include <linux/ip.h>
	19	#include <linux/udp.h>
	20	#include <linux/icmp.h>
	21	#include <net/icmp.h>
	22	#include <net/ip.h>
	23	#include <net/tcp.h>
	24	#include <net/route.h>
	25	#include <net/dst.h>
	26	#include <linux/netfilter_ipv4/ip_tables.h>
	27	#include <linux/netfilter_ipv4/ipt_REJECT.h>
	28	#ifdef CONFIG_BRIDGE_NETFILTER
	29	#include <linux/netfilter_bridge.h>
	30	#endif
	31
	32	MODULE_LICENSE("GPL");
	33	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	34	MODULE_DESCRIPTION("iptables REJECT target module");
	35
	36	#if 0
	37	#define DEBUGP printk
	38	#else
	39	#define DEBUGP(format, args...)
	40	#endif
	41
	42	static inline struct rtable route_reverse(struct sk_buff skb,
	43	struct tcphdr *tcph, int hook)
	44	{
	45	struct iphdr *iph = skb->nh.iph;
	46	struct dst_entry *odst;
	47	struct flowi fl = {};
	48	struct rtable *rt;
	49
	50	/* We don't require ip forwarding to be enabled to be able to
	51	* send a RST reply for bridged traffic. */
	52	if (hook != NF_IP_FORWARD
	53	#ifdef CONFIG_BRIDGE_NETFILTER
	54	\|\| (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
	55	#endif
	56	) {
	57	fl.nl_u.ip4_u.daddr = iph->saddr;
	58	if (hook == NF_IP_LOCAL_IN)
	59	fl.nl_u.ip4_u.saddr = iph->daddr;
	60	fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
	61
	62	if (ip_route_output_key(&rt, &fl) != 0)
	63	return NULL;
	64	} else {
65	/* non-local src, find valid iif to satisfy
66	* rp-filter when calling ip_route_input. */
67	fl.nl_u.ip4_u.daddr = iph->daddr;
68	if (ip_route_output_key(&rt, &fl) != 0)
69	return NULL;
70
71	odst = skb->dst;
72	if (ip_route_input(skb, iph->saddr, iph->daddr,
73	RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
74	dst_release(&rt->u.dst);
75	return NULL;
76	}
77	dst_release(&rt->u.dst);
78	rt = (struct rtable *)skb->dst;
79	skb->dst = odst;
80
81	fl.nl_u.ip4_u.daddr = iph->saddr;
82	fl.nl_u.ip4_u.saddr = iph->daddr;
83	fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
84	}
85
86	if (rt->u.dst.error) {
87	dst_release(&rt->u.dst);
88	return NULL;
89	}
90
91	fl.proto = IPPROTO_TCP;
92	fl.fl_ip_sport = tcph->dest;
93	fl.fl_ip_dport = tcph->source;
94
95	if (xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0)) {
96	dst_release(&rt->u.dst);
97	rt = NULL;
98	}
99
100	return rt;
101	}
102
103	/* Send RST reply */
104	static void send_reset(struct sk_buff *oldskb, int hook)
105	{
106	struct sk_buff *nskb;
6150bacf	107	struct iphdr *iph = oldskb->nh.iph;
1da177e4 LT	108	struct tcphdr _otcph, oth, tcph;
	109	struct rtable *rt;
	110	u_int16_t tmp_port;
	111	u_int32_t tmp_addr;
6150bacf	112	unsigned int tcplen;
1da177e4 LT	113	int needs_ack;
	114	int hh_len;
	115
	116	/* IP header checks: fragment. */
	117	if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
	118	return;
	119
	120	oth = skb_header_pointer(oldskb, oldskb->nh.iph->ihl * 4,
	121	sizeof(_otcph), &_otcph);
	122	if (oth == NULL)
	123	return;
	124
	125	/* No RST for RST. */
	126	if (oth->rst)
	127	return;
	128
6150bacf PM	129	/* Check checksum */
	130	tcplen = oldskb->len - iph->ihl * 4;
	131	if (((hook != NF_IP_LOCAL_IN && oldskb->ip_summed != CHECKSUM_HW) \|\|
	132	(hook == NF_IP_LOCAL_IN &&
	133	oldskb->ip_summed != CHECKSUM_UNNECESSARY)) &&
	134	csum_tcpudp_magic(iph->saddr, iph->daddr, tcplen, IPPROTO_TCP,
	135	oldskb->ip_summed == CHECKSUM_HW ? oldskb->csum :
	136	skb_checksum(oldskb, iph->ihl * 4, tcplen, 0)))
	137	return;
	138
1da177e4 LT	139	if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
	140	return;
	141
	142	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
	143
	144	/* We need a linear, writeable skb. We also need to expand
	145	headroom in case hh_len of incoming interface < hh_len of
	146	outgoing interface */
	147	nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
	148	GFP_ATOMIC);
	149	if (!nskb) {
	150	dst_release(&rt->u.dst);
	151	return;
	152	}
	153
	154	dst_release(nskb->dst);
	155	nskb->dst = &rt->u.dst;
	156
	157	/* This packet will not be the same as the other: clear nf fields */
	158	nf_reset(nskb);
1da177e4 LT	159	nskb->nfmark = 0;
	160	#ifdef CONFIG_BRIDGE_NETFILTER
	161	nf_bridge_put(nskb->nf_bridge);
	162	nskb->nf_bridge = NULL;
	163	#endif
	164
	165	tcph = (struct tcphdr )((u_int32_t)nskb->nh.iph + nskb->nh.iph->ihl);
	166
	167	/* Swap source and dest */
	168	tmp_addr = nskb->nh.iph->saddr;
	169	nskb->nh.iph->saddr = nskb->nh.iph->daddr;
	170	nskb->nh.iph->daddr = tmp_addr;
	171	tmp_port = tcph->source;
	172	tcph->source = tcph->dest;
	173	tcph->dest = tmp_port;
	174
	175	/* Truncate to length (no data) */
	176	tcph->doff = sizeof(struct tcphdr)/4;
	177	skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
	178	nskb->nh.iph->tot_len = htons(nskb->len);
	179
	180	if (tcph->ack) {
	181	needs_ack = 0;
	182	tcph->seq = oth->ack_seq;
	183	tcph->ack_seq = 0;
	184	} else {
	185	needs_ack = 1;
	186	tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin
	187	+ oldskb->len - oldskb->nh.iph->ihl*4
	188	- (oth->doff<<2));
	189	tcph->seq = 0;
	190	}
	191
	192	/* Reset flags */
	193	((u_int8_t *)tcph)[13] = 0;
	194	tcph->rst = 1;
	195	tcph->ack = needs_ack;
	196
	197	tcph->window = 0;
	198	tcph->urg_ptr = 0;
	199
	200	/* Adjust TCP checksum */
	201	tcph->check = 0;
	202	tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
	203	nskb->nh.iph->saddr,
	204	nskb->nh.iph->daddr,
	205	csum_partial((char *)tcph,
	206	sizeof(struct tcphdr), 0));
	207
	208	/* Adjust IP TTL, DF */
	209	nskb->nh.iph->ttl = MAXTTL;
	210	/* Set DF, id = 0 */
	211	nskb->nh.iph->frag_off = htons(IP_DF);
	212	nskb->nh.iph->id = 0;
	213
	214	/* Adjust IP checksum */
	215	nskb->nh.iph->check = 0;
	216	nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph,
	217	nskb->nh.iph->ihl);
	218
	219	/* "Never happens" */
	220	if (nskb->len > dst_mtu(nskb->dst))
	221	goto free_nskb;
	222
223	nf_ct_attach(nskb, oldskb);
224
225	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
226	dst_output);
227	return;
228
229	free_nskb:
230	kfree_skb(nskb);
231	}
232
233	static inline void send_unreach(struct sk_buff *skb_in, int code)
234	{
235	icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0);
236	}
237
238	static unsigned int reject(struct sk_buff **pskb,
239	const struct net_device *in,
240	const struct net_device *out,
241	unsigned int hooknum,
242	const void *targinfo,
243	void *userinfo)
244	{
245	const struct ipt_reject_info *reject = targinfo;
246
247	/* Our naive response construction doesn't deal with IP
248	options, and probably shouldn't try. */
249	if ((*pskb)->nh.iph->ihl<<2 != sizeof(struct iphdr))
250	return NF_DROP;
251
252	/* WARNING: This code causes reentry within iptables.
253	This means that the iptables jump stack is now crap. We
254	must return an absolute verdict. --RR */
255	switch (reject->with) {
256	case IPT_ICMP_NET_UNREACHABLE:
257	send_unreach(*pskb, ICMP_NET_UNREACH);
258	break;
259	case IPT_ICMP_HOST_UNREACHABLE:
260	send_unreach(*pskb, ICMP_HOST_UNREACH);
261	break;
262	case IPT_ICMP_PROT_UNREACHABLE:
263	send_unreach(*pskb, ICMP_PROT_UNREACH);
264	break;
265	case IPT_ICMP_PORT_UNREACHABLE:
266	send_unreach(*pskb, ICMP_PORT_UNREACH);
267	break;
268	case IPT_ICMP_NET_PROHIBITED:
269	send_unreach(*pskb, ICMP_NET_ANO);
270	break;
271	case IPT_ICMP_HOST_PROHIBITED:
272	send_unreach(*pskb, ICMP_HOST_ANO);
273	break;
274	case IPT_ICMP_ADMIN_PROHIBITED:
275	send_unreach(*pskb, ICMP_PKT_FILTERED);
276	break;
277	case IPT_TCP_RESET:
278	send_reset(*pskb, hooknum);
279	case IPT_ICMP_ECHOREPLY:
280	/* Doesn't happen. */
281	break;
282	}
283
284	return NF_DROP;
285	}
286
287	static int check(const char *tablename,
288	const struct ipt_entry *e,
289	void *targinfo,
290	unsigned int targinfosize,
291	unsigned int hook_mask)
292	{
293	const struct ipt_reject_info *rejinfo = targinfo;
294
295	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_reject_info))) {
296	DEBUGP("REJECT: targinfosize %u != 0\n", targinfosize);
297	return 0;
298	}
299
300	/* Only allow these for packet filtering. */
301	if (strcmp(tablename, "filter") != 0) {
302	DEBUGP("REJECT: bad table `%s'.\n", tablename);
303	return 0;
304	}
305	if ((hook_mask & ~((1 << NF_IP_LOCAL_IN)
306	\| (1 << NF_IP_FORWARD)
307	\| (1 << NF_IP_LOCAL_OUT))) != 0) {
308	DEBUGP("REJECT: bad hook mask %X\n", hook_mask);
309	return 0;
310	}
311
312	if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
313	printk("REJECT: ECHOREPLY no longer supported.\n");
314	return 0;
315	} else if (rejinfo->with == IPT_TCP_RESET) {
316	/* Must specify that it's a TCP packet */
317	if (e->ip.proto != IPPROTO_TCP
318	\|\| (e->ip.invflags & IPT_INV_PROTO)) {
319	DEBUGP("REJECT: TCP_RESET invalid for non-tcp\n");
320	return 0;
321	}
322	}
323
324	return 1;
325	}
326
327	static struct ipt_target ipt_reject_reg = {
328	.name = "REJECT",
329	.target = reject,
330	.checkentry = check,
331	.me = THIS_MODULE,
332	};
333
334	static int __init init(void)
335	{
336	return ipt_register_target(&ipt_reject_reg);
337	}
338
339	static void __exit fini(void)
340	{
341	ipt_unregister_target(&ipt_reject_reg);
342	}
343
344	module_init(init);
345	module_exit(fini);