target/linux/generic-2.6/patches-2.6.21/170-netfilter_chaostables_0.8.patch

   1 --- a/include/linux/netfilter/Kbuild
   2 +++ b/include/linux/netfilter/Kbuild
   3 @@ -3,6 +3,7 @@
   4  header-y += nfnetlink_conntrack.h
   5  header-y += nfnetlink_log.h
   6  header-y += nfnetlink_queue.h
   7 +header-y += xt_CHAOS.h
   8  header-y += xt_CLASSIFY.h
   9  header-y += xt_comment.h
  10  header-y += xt_connbytes.h
  11 Index: linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
  12 ===================================================================
  13 --- /dev/null
  14 +++ linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
  15 @@ -0,0 +1,5 @@
  16 +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
  17 +#      include <linux/netfilter_ipv4/ip_conntrack.h>
  18 +#else /* linux-2.6.20+ */
  19 +#      include <net/netfilter/nf_nat_rule.h>
  20 +#endif
  21 Index: linux-2.6.21.7/include/linux/netfilter/oot_trans.h
  22 ===================================================================
  23 --- /dev/null
  24 +++ linux-2.6.21.7/include/linux/netfilter/oot_trans.h
  25 @@ -0,0 +1,14 @@
  26 +/* Out of tree workarounds */
  27 +#include <linux/version.h>
  28 +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
  29 +#      define HAVE_MATCHINFOSIZE 1
  30 +#      define HAVE_TARGUSERINFO 1
  31 +#      define HAVE_TARGINFOSIZE 1
  32 +#endif
  33 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
  34 +#      define nfmark mark
  35 +#endif
  36 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 21)
  37 +#      define tcp_v4_check(tcph, tcph_sz, s, d, csp) \
  38 +               tcp_v4_check((tcph_sz), (s), (d), (csp))
  39 +#endif
  40 Index: linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
  41 ===================================================================
  42 --- /dev/null
  43 +++ linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
  44 @@ -0,0 +1,14 @@
  45 +#ifndef _LINUX_NETFILTER_XT_CHAOS_H
  46 +#define _LINUX_NETFILTER_XT_CHAOS_H 1
  47 +
  48 +enum xt_chaos_target_variant {
  49 +       XTCHAOS_NORMAL,
  50 +       XTCHAOS_TARPIT,
  51 +       XTCHAOS_DELUDE,
  52 +};
  53 +
  54 +struct xt_chaos_target_info {
  55 +       uint8_t variant;
  56 +};
  57 +
  58 +#endif /* _LINUX_NETFILTER_XT_CHAOS_H */
  59 Index: linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
  60 ===================================================================
  61 --- /dev/null
  62 +++ linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
  63 @@ -0,0 +1,8 @@
  64 +#ifndef _LINUX_NETFILTER_XT_PORTSCAN_H
  65 +#define _LINUX_NETFILTER_XT_PORTSCAN_H 1
  66 +
  67 +struct xt_portscan_match_info {
  68 +       uint8_t match_stealth, match_syn, match_cn, match_gr;
  69 +};
  70 +
  71 +#endif /* _LINUX_NETFILTER_XT_PORTSCAN_H */
  72 Index: linux-2.6.21.7/net/netfilter/find_match.c
  73 ===================================================================
  74 --- /dev/null
  75 +++ linux-2.6.21.7/net/netfilter/find_match.c
  76 @@ -0,0 +1,39 @@
  77 +/*
  78 +    xt_request_find_match
  79 +    by Jan Engelhardt <jengelh [at] gmx de>, 2006 - 2007
  80 +
  81 +    Based upon linux-2.6.18.5/net/netfilter/x_tables.c:
  82 +    Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
  83 +    This program is free software; you can redistribute it and/or modify
  84 +    it under the terms of the GNU General Public License version 2 as
  85 +    published by the Free Software Foundation.
  86 +*/
  87 +#include <linux/err.h>
  88 +#include <linux/netfilter_arp.h>
  89 +#include <linux/socket.h>
  90 +#include <linux/netfilter/x_tables.h>
  91 +
  92 +/*
  93 + * Yeah this code is sub-optimal, but the function is missing in
  94 + * mainline so far. -jengelh
  95 + */
  96 +static struct xt_match *xt_request_find_match_lo(int af, const char *name,
  97 +    u8 revision)
  98 +{
  99 +       static const char *const xt_prefix[] = {
 100 +               [AF_INET]  = "ip",
 101 +               [AF_INET6] = "ip6",
 102 +               [NF_ARP]   = "arp",
 103 +       };
 104 +       struct xt_match *match;
 105 +
 106 +       match = try_then_request_module(xt_find_match(af, name, revision),
 107 +               "%st_%s", xt_prefix[af], name);
 108 +       if (IS_ERR(match) || match == NULL)
 109 +               return NULL;
 110 +
 111 +       return match;
 112 +}
 113 +
 114 +/* In case it goes into mainline, let this out-of-tree package compile */
 115 +#define xt_request_find_match xt_request_find_match_lo
 116 Index: linux-2.6.21.7/net/netfilter/Kconfig
 117 ===================================================================
 118 --- linux-2.6.21.7.orig/net/netfilter/Kconfig
 119 +++ linux-2.6.21.7/net/netfilter/Kconfig
 120 @@ -287,6 +287,14 @@ config NETFILTER_XTABLES
 121
 122  # alphabetically ordered list of targets
 123
 124 +config NETFILTER_XT_TARGET_CHAOS
 125 +       tristate '"CHAOS" target support'
 126 +       depends on NETFILTER_XTABLES
 127 +       help
 128 +         This option adds a `CHAOS' target.
 129 +
 130 +         To compile it as a module, choose M here.  If unsure, say N.
 131 +
 132  config NETFILTER_XT_TARGET_CLASSIFY
 133         tristate '"CLASSIFY" target support'
 134         depends on NETFILTER_XTABLES
 135 @@ -315,6 +323,14 @@ config NETFILTER_XT_TARGET_CONNMARK
 136           <file:Documentation/modules.txt>.  The module will be called
 137           ipt_CONNMARK.o.  If unsure, say `N'.
 138
 139 +config NETFILTER_XT_TARGET_DELUDE
 140 +       tristate '"DELUDE" target support'
 141 +       depends on NETFILTER_XTABLES
 142 +       help
 143 +         This option adds a `DELUDE' target.
 144 +
 145 +         To compile it as a module, choose M here.  If unsure, say N.
 146 +
 147  config NETFILTER_XT_TARGET_DSCP
 148         tristate '"DSCP" target support'
 149         depends on NETFILTER_XTABLES
 150 @@ -563,6 +579,14 @@ config NETFILTER_XT_MATCH_POLICY
 151
 152           To compile it as a module, choose M here.  If unsure, say N.
 153
 154 +config NETFILTER_XT_MATCH_PORTSCAN
 155 +       tristate '"portscan" match support'
 156 +       depends on NETFILTER_XTABLES
 157 +       help
 158 +         This option adds a 'portscan' match support.
 159 +
 160 +         To compile it as a module, choose M here.  If unsure, say N.
 161 +
 162  config NETFILTER_XT_MATCH_MULTIPORT
 163         tristate "Multiple port match support"
 164         depends on NETFILTER_XTABLES
 165 Index: linux-2.6.21.7/net/netfilter/Makefile
 166 ===================================================================
 167 --- linux-2.6.21.7.orig/net/netfilter/Makefile
 168 +++ linux-2.6.21.7/net/netfilter/Makefile
 169 @@ -47,6 +47,8 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK
 170  obj-$(CONFIG_NETFILTER_XT_TARGET_SECMARK) += xt_SECMARK.o
 171  obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o
 172  obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o
 173 +obj-$(CONFIG_NETFILTER_XT_TARGET_CHAOS) += xt_CHAOS.o
 174 +obj-$(CONFIG_NETFILTER_XT_TARGET_DELUDE) += xt_DELUDE.o
 175
 176  # matches
 177  obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o
 178 @@ -74,3 +76,4 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_STRING)
 179  obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
 180  obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
 181  obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o
 182 +obj-$(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) += xt_portscan.o
 183 Index: linux-2.6.21.7/net/netfilter/xt_CHAOS.c
 184 ===================================================================
 185 --- /dev/null
 186 +++ linux-2.6.21.7/net/netfilter/xt_CHAOS.c
 187 @@ -0,0 +1,200 @@
 188 +/*
 189 + *     CHAOS target for netfilter
 190 + *     Copyright © CC Computer Consultants GmbH, 2006 - 2007
 191 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 192 + *
 193 + *     This program is free software; you can redistribute it and/or modify
 194 + *     it under the terms of the GNU General Public License; either version
 195 + *     2 or 3 as published by the Free Software Foundation.
 196 + */
 197 +#include <linux/icmp.h>
 198 +#include <linux/in.h>
 199 +#include <linux/ip.h>
 200 +#include <linux/module.h>
 201 +#include <linux/skbuff.h>
 202 +#include <linux/stat.h>
 203 +#include <linux/netfilter/x_tables.h>
 204 +#include <linux/netfilter/xt_tcpudp.h>
 205 +#include <linux/netfilter_ipv4/ipt_REJECT.h>
 206 +#include <net/ip.h>
 207 +#if defined(_LOCAL)
 208 +#      include "xt_CHAOS.h"
 209 +#      include "find_match.c"
 210 +#elif defined(CONFIG_NETFILTER_XT_TARGET_CHAOS) || \
 211 +    defined(CONFIG_NETFILTER_XT_TARGET_CHAOS_MODULE)
 212 +#      include <linux/netfilter/xt_CHAOS.h>
 213 +#      include "find_match.c"
 214 +#else
 215 +#      include "xt_CHAOS.h"
 216 +#      include "find_match.c"
 217 +#endif
 218 +#define PFX KBUILD_MODNAME ": "
 219 +
 220 +/* Module parameters */
 221 +static unsigned int reject_percentage = ~0U * .01;
 222 +static unsigned int delude_percentage = ~0U * .0101;
 223 +module_param(reject_percentage, uint, S_IRUGO | S_IWUSR);
 224 +module_param(delude_percentage, uint, S_IRUGO | S_IWUSR);
 225 +
 226 +/* References to other matches/targets */
 227 +static struct xt_match *xm_tcp;
 228 +static struct xt_target *xt_delude, *xt_reject, *xt_tarpit;
 229 +
 230 +static int have_delude, have_tarpit;
 231 +
 232 +/* Static data for other matches/targets */
 233 +static const struct ipt_reject_info reject_params = {
 234 +       .with = ICMP_HOST_UNREACH,
 235 +};
 236 +
 237 +static const struct xt_tcp tcp_params = {
 238 +       .spts = {0, ~0},
 239 +       .dpts = {0, ~0},
 240 +};
 241 +
 242 +/* CHAOS functions */
 243 +static void xt_chaos_total(const struct xt_chaos_target_info *info,
 244 +    struct sk_buff **pskb, const struct net_device *in,
 245 +    const struct net_device *out, unsigned int hooknum)
 246 +{
 247 +       const struct iphdr *iph = ip_hdr(*pskb);
 248 +       const int protoff       = 4 * iph->ihl;
 249 +       const int offset        = ntohs(iph->frag_off) & IP_OFFSET;
 250 +       const struct xt_target *destiny;
 251 +       int hotdrop = 0, ret;
 252 +
 253 +       ret = xm_tcp->match(*pskb, in, out, xm_tcp, &tcp_params,
 254 +                           offset, protoff, &hotdrop);
 255 +       if (!ret || hotdrop || (unsigned int)net_random() > delude_percentage)
 256 +               return;
 257 +
 258 +       destiny = (info->variant == XTCHAOS_TARPIT) ? xt_tarpit : xt_delude;
 259 +       destiny->target(pskb, in, out, hooknum, destiny, NULL);
 260 +       return;
 261 +}
 262 +
 263 +static unsigned int chaos_tg(struct sk_buff **pskb,
 264 +    const struct net_device *in, const struct net_device *out,
 265 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
 266 +{
 267 +       /*
 268 +        * Equivalent to:
 269 +        * -A chaos -m statistic --mode random --probability \
 270 +        *         $reject_percentage -j REJECT --reject-with host-unreach;
 271 +        * -A chaos -p tcp -m statistic --mode random --probability \
 272 +        *         $delude_percentage -j DELUDE;
 273 +        * -A chaos -j DROP;
 274 +        */
 275 +       const struct xt_chaos_target_info *info = targinfo;
 276 +       const struct iphdr *iph = ip_hdr(*pskb);
 277 +
 278 +       if ((unsigned int)net_random() <= reject_percentage)
 279 +               return xt_reject->target(pskb, in, out, hooknum, target,
 280 +                      &reject_params);
 281 +
 282 +       /* TARPIT/DELUDE may not be called from the OUTPUT chain */
 283 +       if (iph->protocol == IPPROTO_TCP &&
 284 +           info->variant != XTCHAOS_NORMAL && hooknum != NF_IP_LOCAL_OUT)
 285 +               xt_chaos_total(info, pskb, in, out, hooknum);
 286 +
 287 +       return NF_DROP;
 288 +}
 289 +
 290 +static int chaos_tg_check(const char *tablename, const void *entry,
 291 +    const struct xt_target *target, void *targinfo, unsigned int hook_mask)
 292 +{
 293 +       const struct xt_chaos_target_info *info = targinfo;
 294 +
 295 +       if (info->variant == XTCHAOS_DELUDE && !have_delude) {
 296 +               printk(KERN_WARNING PFX "Error: Cannot use --delude when "
 297 +                      "DELUDE module not available\n");
 298 +               return false;
 299 +       }
 300 +       if (info->variant == XTCHAOS_TARPIT && !have_tarpit) {
 301 +               printk(KERN_WARNING PFX "Error: Cannot use --tarpit when "
 302 +                      "TARPIT module not available\n");
 303 +               return false;
 304 +       }
 305 +
 306 +       return true;
 307 +}
 308 +
 309 +static struct xt_target chaos_tg_reg = {
 310 +       .name       = "CHAOS",
 311 +       .family     = AF_INET,
 312 +       .table      = "filter",
 313 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
 314 +                     (1 << NF_IP_LOCAL_OUT),
 315 +       .checkentry = chaos_tg_check,
 316 +       .target     = chaos_tg,
 317 +       .targetsize = sizeof(struct xt_chaos_target_info),
 318 +       .me         = THIS_MODULE,
 319 +};
 320 +
 321 +static int __init chaos_tg_init(void)
 322 +{
 323 +       int ret = -EINVAL;
 324 +
 325 +       xm_tcp = xt_request_find_match(AF_INET, "tcp", 0);
 326 +       if (xm_tcp == NULL) {
 327 +               printk(KERN_WARNING PFX "Error: Could not find or load "
 328 +                      "\"tcp\" match\n");
 329 +               return -EINVAL;
 330 +       }
 331 +
 332 +       xt_reject = xt_request_find_target(AF_INET, "REJECT", 0);
 333 +       if (xt_reject == NULL) {
 334 +               printk(KERN_WARNING PFX "Error: Could not find or load "
 335 +                      "\"REJECT\" target\n");
 336 +               goto out2;
 337 +       }
 338 +
 339 +       xt_tarpit   = xt_request_find_target(AF_INET, "TARPIT", 0);
 340 +       have_tarpit = xt_tarpit != NULL;
 341 +       if (!have_tarpit)
 342 +               printk(KERN_WARNING PFX "Warning: Could not find or load "
 343 +                      "\"TARPIT\" target\n");
 344 +
 345 +       xt_delude   = xt_request_find_target(AF_INET, "DELUDE", 0);
 346 +       have_delude = xt_delude != NULL;
 347 +       if (!have_delude)
 348 +               printk(KERN_WARNING PFX "Warning: Could not find or load "
 349 +                      "\"DELUDE\" target\n");
 350 +
 351 +       if ((ret = xt_register_target(&chaos_tg_reg)) != 0) {
 352 +               printk(KERN_WARNING PFX "xt_register_target returned "
 353 +                      "error %d\n", ret);
 354 +               goto out3;
 355 +       }
 356 +
 357 +       return 0;
 358 +
 359 + out3:
 360 +       if (have_delude)
 361 +               module_put(xt_delude->me);
 362 +       if (have_tarpit)
 363 +               module_put(xt_tarpit->me);
 364 +       module_put(xt_reject->me);
 365 + out2:
 366 +       module_put(xm_tcp->me);
 367 +       return ret;
 368 +}
 369 +
 370 +static void __exit chaos_tg_exit(void)
 371 +{
 372 +       xt_unregister_target(&chaos_tg_reg);
 373 +       module_put(xm_tcp->me);
 374 +       module_put(xt_reject->me);
 375 +       if (have_delude)
 376 +               module_put(xt_delude->me);
 377 +       if (have_tarpit)
 378 +               module_put(xt_tarpit->me);
 379 +       return;
 380 +}
 381 +
 382 +module_init(chaos_tg_init);
 383 +module_exit(chaos_tg_exit);
 384 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 385 +MODULE_DESCRIPTION("netfilter \"CHAOS\" target");
 386 +MODULE_LICENSE("GPL");
 387 +MODULE_ALIAS("ipt_CHAOS");
 388 Index: linux-2.6.21.7/net/netfilter/xt_DELUDE.c
 389 ===================================================================
 390 --- /dev/null
 391 +++ linux-2.6.21.7/net/netfilter/xt_DELUDE.c
 392 @@ -0,0 +1,197 @@
 393 +/*
 394 + *     DELUDE target
 395 + *     Copyright © CC Computer Consultants GmbH, 2007
 396 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 397 + *
 398 + *     Based upon linux-2.6.18.5/net/ipv4/netfilter/ipt_REJECT.c:
 399 + *     (C) 1999-2001 Paul `Rusty' Russell
 400 + *     (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 401 + *
 402 + *     xt_DELUDE acts like REJECT, but does reply with SYN-ACK on SYN.
 403 + *
 404 + *     This program is free software; you can redistribute it and/or modify
 405 + *     it under the terms of the GNU General Public License version 2 as
 406 + *     published by the Free Software Foundation.
 407 + */
 408 +#include <linux/module.h>
 409 +#include <linux/skbuff.h>
 410 +#include <linux/ip.h>
 411 +#include <linux/tcp.h>
 412 +#include <linux/netfilter/x_tables.h>
 413 +#ifdef CONFIG_BRIDGE_NETFILTER
 414 +#      include <linux/netfilter_bridge.h>
 415 +#endif
 416 +#include <net/tcp.h>
 417 +#define PFX KBUILD_MODNAME ": "
 418 +
 419 +static void delude_send_reset(struct sk_buff *oldskb, unsigned int hook)
 420 +{
 421 +       struct tcphdr _otcph, *oth, *tcph;
 422 +       unsigned int addr_type;
 423 +       struct sk_buff *nskb;
 424 +       u_int16_t tmp_port;
 425 +       u_int32_t tmp_addr;
 426 +       struct iphdr *niph;
 427 +       bool needs_ack;
 428 +
 429 +       /* IP header checks: fragment. */
 430 +       if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
 431 +               return;
 432 +
 433 +       oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
 434 +                                sizeof(_otcph), &_otcph);
 435 +       if (oth == NULL)
 436 +               return;
 437 +
 438 +       /* No RST for RST. */
 439 +       if (oth->rst)
 440 +               return;
 441 +
 442 +       /* Check checksum */
 443 +       if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
 444 +               return;
 445 +
 446 +       /* We need a linear, writeable skb.  We also need to expand
 447 +          headroom in case hh_len of incoming interface < hh_len of
 448 +          outgoing interface */
 449 +       nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
 450 +                              GFP_ATOMIC);
 451 +       if (!nskb)
 452 +               return;
 453 +
 454 +       /* This packet will not be the same as the other: clear nf fields */
 455 +       nf_reset(nskb);
 456 +       nskb->mark = 0;
 457 +       skb_init_secmark(nskb);
 458 +
 459 +       skb_shinfo(nskb)->gso_size = 0;
 460 +       skb_shinfo(nskb)->gso_segs = 0;
 461 +       skb_shinfo(nskb)->gso_type = 0;
 462 +
 463 +       tcph = (struct tcphdr *)(skb_network_header(nskb) + ip_hdrlen(nskb));
 464 +
 465 +       /* Swap source and dest */
 466 +       niph         = ip_hdr(nskb);
 467 +       tmp_addr     = niph->saddr;
 468 +       niph->saddr  = niph->daddr;
 469 +       niph->daddr  = tmp_addr;
 470 +       tmp_port     = tcph->source;
 471 +       tcph->source = tcph->dest;
 472 +       tcph->dest   = tmp_port;
 473 +
 474 +       /* Truncate to length (no data) */
 475 +       tcph->doff    = sizeof(struct tcphdr) / 4;
 476 +       skb_trim(nskb, ip_hdrlen(nskb) + sizeof(struct tcphdr));
 477 +       niph->tot_len = htons(nskb->len);
 478 +
 479 +       if (oth->syn && !oth->ack && !oth->rst && !oth->fin) {
 480 +               /* DELUDE essential part */
 481 +               tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
 482 +                               oldskb->len - ip_hdrlen(oldskb) -
 483 +                               (oth->doff << 2));
 484 +               tcph->seq     = false;
 485 +               tcph->ack     = true;
 486 +       } else {
 487 +               if (!tcph->ack) {
 488 +                       needs_ack     = true;
 489 +                       tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn +
 490 +                                       oth->fin + oldskb->len -
 491 +                                       ip_hdrlen(oldskb) - (oth->doff<<2));
 492 +                       tcph->seq     = false;
 493 +               } else {
 494 +                       needs_ack     = false;
 495 +                       tcph->seq     = oth->ack_seq;
 496 +                       tcph->ack_seq = false;
 497 +               }
 498 +
 499 +               /* Reset flags */
 500 +               ((u_int8_t *)tcph)[13] = 0;
 501 +               tcph->rst = true;
 502 +               tcph->ack = needs_ack;
 503 +       }
 504 +
 505 +       tcph->window  = 0;
 506 +       tcph->urg_ptr = 0;
 507 +
 508 +       /* Adjust TCP checksum */
 509 +       tcph->check = 0;
 510 +       tcph->check = tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
 511 +                     niph->daddr, csum_partial((char *)tcph,
 512 +                     sizeof(struct tcphdr), 0));
 513 +
 514 +       /* Set DF, id = 0 */
 515 +       niph->frag_off = htons(IP_DF);
 516 +       niph->id       = 0;
 517 +
 518 +       addr_type = RTN_UNSPEC;
 519 +#ifdef CONFIG_BRIDGE_NETFILTER
 520 +       if (hook != NF_IP_FORWARD || (nskb->nf_bridge != NULL &&
 521 +           nskb->nf_bridge->mask & BRNF_BRIDGED))
 522 +#else
 523 +       if (hook != NF_IP_FORWARD)
 524 +#endif
 525 +               addr_type = RTN_LOCAL;
 526 +
 527 +       if (ip_route_me_harder(&nskb, addr_type))
 528 +               goto free_nskb;
 529 +
 530 +       nskb->ip_summed = CHECKSUM_NONE;
 531 +
 532 +       /* Adjust IP TTL */
 533 +       niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
 534 +
 535 +       /* Adjust IP checksum */
 536 +       niph->check = 0;
 537 +       niph->check = ip_fast_csum(skb_network_header(nskb), niph->ihl);
 538 +
 539 +       /* "Never happens" */
 540 +       if (nskb->len > dst_mtu(nskb->dst))
 541 +               goto free_nskb;
 542 +
 543 +       nf_ct_attach(nskb, oldskb);
 544 +
 545 +       NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
 546 +               dst_output);
 547 +       return;
 548 +
 549 + free_nskb:
 550 +       kfree_skb(nskb);
 551 +}
 552 +
 553 +static unsigned int delude_tg(struct sk_buff **pskb,
 554 +    const struct net_device *in, const struct net_device *out,
 555 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
 556 +{
 557 +       /* WARNING: This code causes reentry within iptables.
 558 +          This means that the iptables jump stack is now crap.  We
 559 +          must return an absolute verdict. --RR */
 560 +       delude_send_reset(*pskb, hooknum);
 561 +       return NF_DROP;
 562 +}
 563 +
 564 +static struct xt_target delude_tg_reg = {
 565 +       .name       = "DELUDE",
 566 +       .family     = AF_INET,
 567 +       .table      = "filter",
 568 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD),
 569 +       .target     = delude_tg,
 570 +       .proto      = IPPROTO_TCP,
 571 +       .me         = THIS_MODULE,
 572 +};
 573 +
 574 +static int __init delude_tg_init(void)
 575 +{
 576 +       return xt_register_target(&delude_tg_reg);
 577 +}
 578 +
 579 +static void __exit delude_tg_exit(void)
 580 +{
 581 +       xt_unregister_target(&delude_tg_reg);
 582 +}
 583 +
 584 +module_init(delude_tg_init);
 585 +module_exit(delude_tg_exit);
 586 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 587 +MODULE_DESCRIPTION("netfilter \"DELUDE\" target");
 588 +MODULE_LICENSE("GPL");
 589 +MODULE_ALIAS("ipt_DELUDE");
 590 Index: linux-2.6.21.7/net/netfilter/xt_portscan.c
 591 ===================================================================
 592 --- /dev/null
 593 +++ linux-2.6.21.7/net/netfilter/xt_portscan.c
 594 @@ -0,0 +1,269 @@
 595 +/*
 596 + *     portscan match for netfilter
 597 + *     Copyright © CC Computer Consultants GmbH, 2006 - 2007
 598 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 599 + *
 600 + *     This program is free software; you can redistribute it and/or modify
 601 + *     it under the terms of the GNU General Public License; either version
 602 + *     2 or 3 as published by the Free Software Foundation.
 603 + */
 604 +#include <linux/in.h>
 605 +#include <linux/ip.h>
 606 +#include <linux/module.h>
 607 +#include <linux/moduleparam.h>
 608 +#include <linux/skbuff.h>
 609 +#include <linux/stat.h>
 610 +#include <linux/tcp.h>
 611 +#include <linux/types.h>
 612 +#include <linux/version.h>
 613 +#include <linux/netfilter/x_tables.h>
 614 +#include <linux/netfilter/xt_tcpudp.h>
 615 +#include <net/netfilter/nf_nat_rule.h>
 616 +#if defined(_LOCAL)
 617 +#      include "xt_portscan.h"
 618 +#elif defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) || \
 619 +    defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN_MODULE)
 620 +#      include <linux/netfilter/xt_portscan.h>
 621 +#else
 622 +#      include "xt_portscan.h"
 623 +#endif
 624 +#define PFX KBUILD_MODNAME ": "
 625 +
 626 +enum {
 627 +       TCP_FLAGS_ALL3 = TCP_FLAG_FIN | TCP_FLAG_RST | TCP_FLAG_SYN,
 628 +       TCP_FLAGS_ALL4 = TCP_FLAGS_ALL3 | TCP_FLAG_ACK,
 629 +       TCP_FLAGS_ALL6 = TCP_FLAGS_ALL4 | TCP_FLAG_PSH | TCP_FLAG_URG,
 630 +};
 631 +
 632 +/* Module parameters */
 633 +static unsigned int
 634 +       connmark_mask = ~0,
 635 +       packet_mask   = ~0,
 636 +       mark_seen     = 0x9,
 637 +       mark_synrcv   = 0x1,
 638 +       mark_closed   = 0x2,
 639 +       mark_synscan  = 0x3,
 640 +       mark_estab1   = 0x4,
 641 +       mark_estab2   = 0x5,
 642 +       mark_cnscan   = 0x6,
 643 +       mark_grscan   = 0x7,
 644 +       mark_valid    = 0x8;
 645 +
 646 +module_param(connmark_mask, uint, S_IRUGO | S_IWUSR);
 647 +module_param(packet_mask,   uint, S_IRUGO | S_IWUSR);
 648 +module_param(mark_seen,     uint, S_IRUGO | S_IWUSR);
 649 +module_param(mark_synrcv,   uint, S_IRUGO | S_IWUSR);
 650 +module_param(mark_closed,   uint, S_IRUGO | S_IWUSR);
 651 +module_param(mark_synscan,  uint, S_IRUGO | S_IWUSR);
 652 +module_param(mark_estab1,   uint, S_IRUGO | S_IWUSR);
 653 +module_param(mark_estab2,   uint, S_IRUGO | S_IWUSR);
 654 +module_param(mark_cnscan,   uint, S_IRUGO | S_IWUSR);
 655 +module_param(mark_grscan,   uint, S_IRUGO | S_IWUSR);
 656 +module_param(mark_valid,    uint, S_IRUGO | S_IWUSR);
 657 +MODULE_PARM_DESC(connmark_mask, "only set specified bits in connection mark");
 658 +MODULE_PARM_DESC(packet_mask,   "only set specified bits in packet mark");
 659 +MODULE_PARM_DESC(mark_seen,     "nfmark value for packet-seen state");
 660 +MODULE_PARM_DESC(mark_synrcv,   "connmark value for SYN Received state");
 661 +MODULE_PARM_DESC(mark_closed,   "connmark value for closed state");
 662 +MODULE_PARM_DESC(mark_synscan,  "connmark value for SYN Scan state");
 663 +MODULE_PARM_DESC(mark_estab1,   "connmark value for Established-1 state");
 664 +MODULE_PARM_DESC(mark_estab2,   "connmark value for Established-2 state");
 665 +MODULE_PARM_DESC(mark_cnscan,   "connmark value for Connect Scan state");
 666 +MODULE_PARM_DESC(mark_grscan,   "connmark value for Grab Scan state");
 667 +MODULE_PARM_DESC(mark_valid,    "connmark value for Valid state");
 668 +
 669 +/* TCP flag functions */
 670 +static inline bool tflg_ack4(const struct tcphdr *th)
 671 +{
 672 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_ACK;
 673 +}
 674 +
 675 +static inline bool tflg_ack6(const struct tcphdr *th)
 676 +{
 677 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL6) == TCP_FLAG_ACK;
 678 +}
 679 +
 680 +static inline bool tflg_fin(const struct tcphdr *th)
 681 +{
 682 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_FIN;
 683 +}
 684 +
 685 +static inline bool tflg_rst(const struct tcphdr *th)
 686 +{
 687 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_RST;
 688 +}
 689 +
 690 +static inline bool tflg_rstack(const struct tcphdr *th)
 691 +{
 692 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 693 +              (TCP_FLAG_ACK | TCP_FLAG_RST);
 694 +}
 695 +
 696 +static inline bool tflg_syn(const struct tcphdr *th)
 697 +{
 698 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_SYN;
 699 +}
 700 +
 701 +static inline bool tflg_synack(const struct tcphdr *th)
 702 +{
 703 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 704 +              (TCP_FLAG_SYN | TCP_FLAG_ACK);
 705 +}
 706 +
 707 +/* portscan functions */
 708 +static inline bool portscan_mt_stealth(const struct tcphdr *th)
 709 +{
 710 +       /*
 711 +        * "Connection refused" replies to our own probes must not be matched.
 712 +        */
 713 +       if (tflg_rstack(th))
 714 +               return false;
 715 +
 716 +       if (tflg_rst(th) && printk_ratelimit()) {
 717 +               printk(KERN_WARNING PFX "Warning: Pure RST received\n");
 718 +               return false;
 719 +       }
 720 +
 721 +       /*
 722 +        * -p tcp ! --syn -m conntrack --ctstate INVALID: Looking for non-start
 723 +        * packets that are not associated with any connection -- this will
 724 +        * match most scan types (NULL, XMAS, FIN) and ridiculous flag
 725 +        * combinations (SYN-RST, SYN-FIN, SYN-FIN-RST, FIN-RST, etc.).
 726 +        */
 727 +       return !tflg_syn(th);
 728 +}
 729 +
 730 +static inline unsigned int portscan_mt_full(int mark,
 731 +    enum ip_conntrack_info ctstate, bool loopback, const struct tcphdr *tcph,
 732 +    unsigned int payload_len)
 733 +{
 734 +       if (mark == mark_estab2) {
 735 +               /*
 736 +                * -m connmark --mark $ESTAB2
 737 +                */
 738 +               if (tflg_ack4(tcph) && payload_len == 0)
 739 +                       return mark; /* keep mark */
 740 +               else if (tflg_rst(tcph) || tflg_fin(tcph))
 741 +                       return mark_grscan;
 742 +               else
 743 +                       return mark_valid;
 744 +       } else if (mark == mark_estab1) {
 745 +               /*
 746 +                * -m connmark --mark $ESTAB1
 747 +                */
 748 +               if (tflg_rst(tcph) || tflg_fin(tcph))
 749 +                       return mark_cnscan;
 750 +               else if (!loopback && tflg_ack4(tcph) && payload_len == 0)
 751 +                       return mark_estab2;
 752 +               else
 753 +                       return mark_valid;
 754 +       } else if (mark == mark_synrcv) {
 755 +               /*
 756 +                * -m connmark --mark $SYN
 757 +                */
 758 +               if (loopback && tflg_synack(tcph))
 759 +                       return mark; /* keep mark */
 760 +               else if (loopback && tflg_rstack(tcph))
 761 +                       return mark_closed;
 762 +               else if (tflg_ack6(tcph))
 763 +                       return mark_estab1;
 764 +               else
 765 +                       return mark_synscan;
 766 +       } else if (ctstate == IP_CT_NEW && tflg_syn(tcph)) {
 767 +               /*
 768 +                * -p tcp --syn --ctstate NEW
 769 +                */
 770 +               return mark_synrcv;
 771 +       }
 772 +       return mark;
 773 +}
 774 +
 775 +static int portscan_mt(const struct sk_buff *skb,
 776 +    const struct net_device *in, const struct net_device *out,
 777 +    const struct xt_match *match, const void *matchinfo, int offset,
 778 +    unsigned int protoff, int *hotdrop)
 779 +{
 780 +       const struct xt_portscan_match_info *info = matchinfo;
 781 +       enum ip_conntrack_info ctstate;
 782 +       const struct tcphdr *tcph;
 783 +       struct nf_conn *ctdata;
 784 +       struct tcphdr tcph_buf;
 785 +
 786 +       tcph = skb_header_pointer(skb, protoff, sizeof(tcph_buf), &tcph_buf);
 787 +       if (tcph == NULL)
 788 +               return false;
 789 +
 790 +       /* Check for invalid packets: -m conntrack --ctstate INVALID */
 791 +       if ((ctdata = nf_ct_get(skb, &ctstate)) == NULL) {
 792 +               if (info->match_stealth)
 793 +                       return portscan_mt_stealth(tcph);
 794 +               /*
 795 +                * If @ctdata is NULL, we cannot match the other scan
 796 +                * types, return.
 797 +                */
 798 +               return false;
 799 +       }
 800 +
 801 +       /*
 802 +        * If -m portscan was previously applied to this packet, the rules we
 803 +        * simulate must not be run through again. And for speedup, do not call
 804 +        * it either when the connection is already VALID.
 805 +        */
 806 +       if ((ctdata->mark & connmark_mask) == mark_valid ||
 807 +            (skb->mark & packet_mask) != mark_seen) {
 808 +               unsigned int n;
 809 +
 810 +               n = portscan_mt_full(ctdata->mark & connmark_mask, ctstate,
 811 +                   in == &loopback_dev, tcph,
 812 +                   skb->len - protoff - 4 * tcph->doff);
 813 +
 814 +               ctdata->mark = (ctdata->mark & ~connmark_mask) | n;
 815 +               ((struct sk_buff *)skb)->mark =
 816 +                       (skb->mark & ~packet_mask) ^ mark_seen;
 817 +       }
 818 +
 819 +       return (info->match_syn && ctdata->mark == mark_synscan) ||
 820 +              (info->match_cn && ctdata->mark == mark_cnscan) ||
 821 +              (info->match_gr && ctdata->mark == mark_grscan);
 822 +}
 823 +
 824 +static int portscan_mt_check(const char *tablename, const void *entry,
 825 +    const struct xt_match *match, void *matchinfo, unsigned int hook_mask)
 826 +{
 827 +       const struct xt_portscan_match_info *info = matchinfo;
 828 +
 829 +       if ((info->match_stealth & ~1) || (info->match_syn & ~1) ||
 830 +           (info->match_cn & ~1) || (info->match_gr & ~1)) {
 831 +               printk(KERN_WARNING PFX "Invalid flags\n");
 832 +               return false;
 833 +       }
 834 +       return true;
 835 +}
 836 +
 837 +static struct xt_match portscan_mt_reg __read_mostly = {
 838 +       .name       = "portscan",
 839 +       .family     = AF_INET,
 840 +       .match      = portscan_mt,
 841 +       .checkentry = portscan_mt_check,
 842 +       .matchsize  = sizeof(struct xt_portscan_match_info),
 843 +       .proto      = IPPROTO_TCP,
 844 +       .me         = THIS_MODULE,
 845 +};
 846 +
 847 +static int __init portscan_mt_init(void)
 848 +{
 849 +       return xt_register_match(&portscan_mt_reg);
 850 +}
 851 +
 852 +static void __exit portscan_mt_exit(void)
 853 +{
 854 +       xt_unregister_match(&portscan_mt_reg);
 855 +       return;
 856 +}
 857 +
 858 +module_init(portscan_mt_init);
 859 +module_exit(portscan_mt_exit);
 860 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 861 +MODULE_DESCRIPTION("netfilter \"portscan\" match");
 862 +MODULE_LICENSE("GPL");
 863 +MODULE_ALIAS("ipt_portscan");