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Kbuild	1020 B	-rw-r--r--
Makefile	14.31 KB	-rw-r--r--
Makefile.am	910 B	-rw-r--r--
Makefile.in	13.55 KB	-rw-r--r--
Mbuild	989 B	-rw-r--r--
compat_skbuff.h	325 B	-rw-r--r--
compat_user.h	262 B	-rw-r--r--
compat_xtables.c	1.18 KB	-rw-r--r--
compat_xtables.h	2.52 KB	-rw-r--r--
compat_xtnu.h	1.97 KB	-rw-r--r--
libxt_CHAOS.c	2.56 KB	-rw-r--r--
libxt_CHAOS.man	1 KB	-rw-r--r--
libxt_DELUDE.c	1.11 KB	-rw-r--r--
libxt_DELUDE.man	286 B	-rw-r--r--
libxt_DHCPMAC.c	2.55 KB	-rw-r--r--
libxt_DHCPMAC.man	1.2 KB	-rw-r--r--
libxt_DNETMAP.c	6.62 KB	-rw-r--r--
libxt_DNETMAP.man	7.71 KB	-rw-r--r--
libxt_ECHO.c	1.03 KB	-rw-r--r--
libxt_ECHO.man	141 B	-rw-r--r--
libxt_IPMARK.c	4.71 KB	-rw-r--r--
libxt_IPMARK.man	1.99 KB	-rw-r--r--
libxt_LOGMARK.c	3.27 KB	-rw-r--r--
libxt_LOGMARK.man	312 B	-rw-r--r--
libxt_SYSRQ.c	844 B	-rw-r--r--
libxt_SYSRQ.man	3.67 KB	-rw-r--r--
libxt_TARPIT.c	2.75 KB	-rw-r--r--
libxt_TARPIT.man	2.55 KB	-rw-r--r--
libxt_condition.c	2.5 KB	-rw-r--r--
libxt_condition.man	175 B	-rw-r--r--
libxt_dhcpmac.c	2.52 KB	-rw-r--r--
libxt_dhcpmac.man	207 B	-rw-r--r--
libxt_fuzzy.c	3.37 KB	-rw-r--r--
libxt_fuzzy.man	263 B	-rw-r--r--
libxt_geoip.c	8.21 KB	-rw-r--r--
libxt_geoip.man	1 KB	-rw-r--r--
libxt_gradm.c	2.3 KB	-rw-r--r--
libxt_gradm.man	225 B	-rw-r--r--
libxt_iface.c	7.21 KB	-rw-r--r--
libxt_iface.man	1.39 KB	-rw-r--r--
libxt_ipp2p.c	7.36 KB	-rw-r--r--
libxt_ipp2p.man	1.52 KB	-rw-r--r--
libxt_ipv4options.c	4.32 KB	-rw-r--r--
libxt_ipv4options.man	1.44 KB	-rw-r--r--
libxt_length2.c	4.69 KB	-rw-r--r--
libxt_length2.man	695 B	-rw-r--r--
libxt_lscan.c	2.64 KB	-rw-r--r--
libxt_lscan.man	1.58 KB	-rw-r--r--
libxt_psd.c	5.34 KB	-rw-r--r--
libxt_psd.man	720 B	-rw-r--r--
libxt_quota2.c	4.06 KB	-rw-r--r--
libxt_quota2.man	1.6 KB	-rw-r--r--
mac.c	572 B	-rw-r--r--
xt_CHAOS.c	6.29 KB	-rw-r--r--
xt_CHAOS.h	249 B	-rw-r--r--
xt_DELUDE.c	4.96 KB	-rw-r--r--
xt_DHCPMAC.c	4.18 KB	-rw-r--r--
xt_DHCPMAC.h	311 B	-rw-r--r--
xt_DNETMAP.c	25.22 KB	-rw-r--r--
xt_DNETMAP.h	402 B	-rw-r--r--
xt_ECHO.c	6.98 KB	-rw-r--r--
xt_IPMARK.c	2.75 KB	-rw-r--r--
xt_IPMARK.h	252 B	-rw-r--r--
xt_LOGMARK.c	3.96 KB	-rw-r--r--
xt_LOGMARK.h	209 B	-rw-r--r--
xt_SYSRQ.c	9.75 KB	-rw-r--r--
xt_TARPIT.c	14.94 KB	-rw-r--r--
xt_TARPIT.h	258 B	-rw-r--r--
xt_condition.c	6.75 KB	-rw-r--r--
xt_condition.h	276 B	-rw-r--r--
xt_fuzzy.c	4.65 KB	-rw-r--r--
xt_fuzzy.h	397 B	-rw-r--r--
xt_geoip.c	8.73 KB	-rw-r--r--
xt_geoip.h	1.34 KB	-rw-r--r--
xt_gradm.h	108 B	-rw-r--r--
xt_iface.c	3.32 KB	-rw-r--r--
xt_iface.h	596 B	-rw-r--r--
xt_ipp2p.c	23.63 KB	-rw-r--r--
xt_ipp2p.h	995 B	-rw-r--r--
xt_ipv4options.c	1.96 KB	-rw-r--r--
xt_ipv4options.h	581 B	-rw-r--r--
xt_length2.c	6.99 KB	-rw-r--r--
xt_length2.h	457 B	-rw-r--r--
xt_lscan.c	7.85 KB	-rw-r--r--
xt_lscan.h	200 B	-rw-r--r--
xt_psd.c	14.2 KB	-rw-r--r--
xt_psd.h	792 B	-rw-r--r--
xt_quota2.c	9 KB	-rw-r--r--
xt_quota2.h	478 B	-rw-r--r--

Code Editor : xt_ECHO.c

/*
 *	"ECHO" (RFC 862) target extension for Xtables
 *	Sample module for "Writing your own Netfilter Modules"
 *	Copyright © Jan Engelhardt, 2008-2011
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License; either
 *	version 2 of the License, or any later version, as published by the
 *	Free Software Foundation.
 */

#include <linux/ip.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/netfilter/x_tables.h>
#ifdef CONFIG_BRIDGE_NETFILTER
#	include <linux/netfilter_bridge.h>
#endif
#include <net/ip.h>
#include <net/ip6_checksum.h>
#include <net/ip6_route.h>
#include <net/route.h>
#include "compat_xtables.h"

static unsigned int
echo_tg6(struct sk_buff *oldskb, const struct xt_action_param *par)
{
	const struct udphdr *oldudp;
	const struct ipv6hdr *oldip;
	struct udphdr *newudp, oldudp_buf;
	struct ipv6hdr *newip;
	struct sk_buff *newskb;
	unsigned int data_len;
	void *payload;
	struct flowi6 fl;
	struct dst_entry *dst = NULL;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)
	struct net *net = dev_net((par->state->in != NULL) ? par->state->in : par->state->out);
#else
	struct net *net = dev_net((par->in != NULL) ? par->in : par->out);
#endif

/* This allows us to do the copy operation in fewer lines of code. */
	if (skb_linearize(oldskb) < 0)
		return NF_DROP;

oldip  = ipv6_hdr(oldskb);
	oldudp = skb_header_pointer(oldskb, par->thoff,
	         sizeof(*oldudp), &oldudp_buf);
	if (oldudp == NULL)
		return NF_DROP;
	if (ntohs(oldudp->len) <= sizeof(*oldudp))
		return NF_DROP;

newskb = alloc_skb(LL_MAX_HEADER + sizeof(*newip) +
	         ntohs(oldudp->len), GFP_ATOMIC);
	if (newskb == NULL)
		return NF_DROP;

skb_reserve(newskb, LL_MAX_HEADER);
	newskb->protocol = oldskb->protocol;

skb_reset_network_header(newskb);
	newip = (void *)skb_put(newskb, sizeof(*newip));
	newip->version  = oldip->version;
	newip->priority = oldip->priority;
	memcpy(newip->flow_lbl, oldip->flow_lbl, sizeof(newip->flow_lbl));
	newip->nexthdr  = par->target->proto;
	newip->saddr    = oldip->daddr;
	newip->daddr    = oldip->saddr;

skb_reset_transport_header(newskb);
	newudp = (void *)skb_put(newskb, sizeof(*newudp));
	newudp->source = oldudp->dest;
	newudp->dest   = oldudp->source;
	newudp->len    = oldudp->len;

data_len = htons(oldudp->len) - sizeof(*oldudp);
	payload  = skb_header_pointer(oldskb, par->thoff +
	           sizeof(*oldudp), data_len, NULL);
	memcpy(skb_put(newskb, data_len), payload, data_len);
	newip->payload_len = htons(newskb->len);

#if 0
	/*
	 * Since no fields are modified (we just swapped things around),
	 * this works too in our specific echo case.
	 */
	newudp->check = oldudp->check;
#else
	newudp->check = 0;
	newudp->check = csum_ipv6_magic(&newip->saddr, &newip->daddr,
	                ntohs(newudp->len), IPPROTO_UDP,
	                csum_partial(newudp, ntohs(newudp->len), 0));
#endif

memset(&fl, 0, sizeof(fl));
	fl.flowi6_proto = newip->nexthdr;
	memcpy(&fl.saddr, &newip->saddr, sizeof(fl.saddr));
	memcpy(&fl.daddr, &newip->daddr, sizeof(fl.daddr));
	fl.fl6_sport = newudp->source;
	fl.fl6_dport = newudp->dest;
	security_skb_classify_flow((struct sk_buff *)oldskb, flowi6_to_flowi(&fl));
	dst = ip6_route_output(net, NULL, &fl);
	if (dst == NULL || dst->error != 0) {
		dst_release(dst);
		goto free_nskb;
	}

skb_dst_set(newskb, dst);
	newip->hop_limit = ip6_dst_hoplimit(skb_dst(newskb));
	newskb->ip_summed = CHECKSUM_NONE;

/* "Never happens" (?) */
	if (newskb->len > dst_mtu(skb_dst(newskb)))
		goto free_nskb;

nf_ct_attach(newskb, oldskb);
	ip6_local_out(par_net(par), newskb->sk, newskb);
	return NF_DROP;

free_nskb:
	kfree_skb(newskb);
	return NF_DROP;
}

static unsigned int
echo_tg4(struct sk_buff *oldskb, const struct xt_action_param *par)
{
	const struct udphdr *oldudp;
	const struct iphdr *oldip;
	struct udphdr *newudp, oldudp_buf;
	struct iphdr *newip;
	struct sk_buff *newskb;
	unsigned int data_len;
	void *payload;

/* This allows us to do the copy operation in fewer lines of code. */
	if (skb_linearize(oldskb) < 0)
		return NF_DROP;

oldip  = ip_hdr(oldskb);
	oldudp = skb_header_pointer(oldskb, par->thoff,
	         sizeof(*oldudp), &oldudp_buf);
	if (oldudp == NULL)
		return NF_DROP;
	if (ntohs(oldudp->len) <= sizeof(*oldudp))
		return NF_DROP;

newskb = alloc_skb(LL_MAX_HEADER + sizeof(*newip) +
	         ntohs(oldudp->len), GFP_ATOMIC);
	if (newskb == NULL)
		return NF_DROP;

skb_reserve(newskb, LL_MAX_HEADER);
	newskb->protocol = oldskb->protocol;

skb_reset_network_header(newskb);
	newip = (void *)skb_put(newskb, sizeof(*newip));
	newip->version  = oldip->version;
	newip->ihl      = sizeof(*newip) / 4;
	newip->tos      = oldip->tos;
	newip->id       = oldip->id;
	newip->frag_off = 0;
	newip->protocol = oldip->protocol;
	newip->check    = 0;
	newip->saddr    = oldip->daddr;
	newip->daddr    = oldip->saddr;

skb_reset_transport_header(newskb);
	newudp = (void *)skb_put(newskb, sizeof(*newudp));
	newudp->source = oldudp->dest;
	newudp->dest   = oldudp->source;
	newudp->len    = oldudp->len;

#if 0
	/*
	 * Since no fields are modified (we just swapped things around),
	 * this works too in our specific echo case.
	 */
	newudp->check = oldudp->check;
#else
	newudp->check = 0;
	newudp->check = csum_tcpudp_magic(newip->saddr, newip->daddr,
	                ntohs(newudp->len), IPPROTO_UDP,
	                csum_partial(newudp, ntohs(newudp->len), 0));
#endif

/* ip_route_me_harder expects the skb's dst to be set */
	skb_dst_set(newskb, dst_clone(skb_dst(oldskb)));

if (ip_route_me_harder(par_net(par), newskb, RTN_UNSPEC) != 0)
		goto free_nskb;

newip->ttl = ip4_dst_hoplimit(skb_dst(newskb));
	newskb->ip_summed = CHECKSUM_NONE;

/* "Never happens" (?) */
	if (newskb->len > dst_mtu(skb_dst(newskb)))
		goto free_nskb;

nf_ct_attach(newskb, oldskb);
	ip_local_out(par_net(par), newskb->sk, newskb);
	return NF_DROP;

free_nskb:
	kfree_skb(newskb);
	return NF_DROP;
}

static struct xt_target echo_tg_reg[] __read_mostly = {
	{
		.name       = "ECHO",
		.revision   = 0,
		.family     = NFPROTO_IPV6,
		.proto      = IPPROTO_UDP,
		.table      = "filter",
		.target     = echo_tg6,
		.me         = THIS_MODULE,
	},
	{
		.name       = "ECHO",
		.revision   = 0,
		.family     = NFPROTO_IPV4,
		.proto      = IPPROTO_UDP,
		.table      = "filter",
		.target     = echo_tg4,
		.me         = THIS_MODULE,
	},
};

static int __init echo_tg_init(void)
{
	return xt_register_targets(echo_tg_reg, ARRAY_SIZE(echo_tg_reg));
}

static void __exit echo_tg_exit(void)
{
	return xt_unregister_targets(echo_tg_reg, ARRAY_SIZE(echo_tg_reg));
}

module_init(echo_tg_init);
module_exit(echo_tg_exit);
MODULE_AUTHOR("Jan Engelhardt ");
MODULE_DESCRIPTION("Xtables: ECHO diagnosis target");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip6t_ECHO");
MODULE_ALIAS("ipt_ECHO");

${this.title}

Code Editor : xt_ECHO.c