target/linux/generic-2.6/patches/160-netfilter_route.patch

   1 diff -urN linux-2.6.21.1.old/include/linux/netfilter_ipv4/ipt_ROUTE.h linux-2.6.21.1.dev/include/linux/netfilter_ipv4/ipt_ROUTE.h
   2 --- linux-2.6.21.1.old/include/linux/netfilter_ipv4/ipt_ROUTE.h 1970-01-01 01:00:00.000000000 +0100
   3 +++ linux-2.6.21.1.dev/include/linux/netfilter_ipv4/ipt_ROUTE.h 2007-05-26 20:37:08.971856648 +0200
   4 @@ -0,0 +1,23 @@
   5 +/* Header file for iptables ipt_ROUTE target
   6 + *
   7 + * (C) 2002 by Cédric de Launois <delaunois@info.ucl.ac.be>
   8 + *
   9 + * This software is distributed under GNU GPL v2, 1991
  10 + */
  11 +#ifndef _IPT_ROUTE_H_target
  12 +#define _IPT_ROUTE_H_target
  13 +
  14 +#define IPT_ROUTE_IFNAMSIZ 16
  15 +
  16 +struct ipt_route_target_info {
  17 +       char      oif[IPT_ROUTE_IFNAMSIZ];      /* Output Interface Name */
  18 +       char      iif[IPT_ROUTE_IFNAMSIZ];      /* Input Interface Name  */
  19 +       u_int32_t gw;                           /* IP address of gateway */
  20 +       u_int8_t  flags;
  21 +};
  22 +
  23 +/* Values for "flags" field */
  24 +#define IPT_ROUTE_CONTINUE        0x01
  25 +#define IPT_ROUTE_TEE             0x02
  26 +
  27 +#endif /*_IPT_ROUTE_H_target*/
  28 diff -urN linux-2.6.21.1.old/include/linux/netfilter_ipv6/ip6t_ROUTE.h linux-2.6.21.1.dev/include/linux/netfilter_ipv6/ip6t_ROUTE.h
  29 --- linux-2.6.21.1.old/include/linux/netfilter_ipv6/ip6t_ROUTE.h        1970-01-01 01:00:00.000000000 +0100
  30 +++ linux-2.6.21.1.dev/include/linux/netfilter_ipv6/ip6t_ROUTE.h        2007-05-26 20:37:09.001852088 +0200
  31 @@ -0,0 +1,23 @@
  32 +/* Header file for iptables ip6t_ROUTE target
  33 + *
  34 + * (C) 2003 by Cédric de Launois <delaunois@info.ucl.ac.be>
  35 + *
  36 + * This software is distributed under GNU GPL v2, 1991
  37 + */
  38 +#ifndef _IPT_ROUTE_H_target
  39 +#define _IPT_ROUTE_H_target
  40 +
  41 +#define IP6T_ROUTE_IFNAMSIZ 16
  42 +
  43 +struct ip6t_route_target_info {
  44 +       char      oif[IP6T_ROUTE_IFNAMSIZ];     /* Output Interface Name */
  45 +       char      iif[IP6T_ROUTE_IFNAMSIZ];     /* Input Interface Name  */
  46 +       u_int32_t gw[4];                        /* IPv6 address of gateway */
  47 +       u_int8_t  flags;
  48 +};
  49 +
  50 +/* Values for "flags" field */
  51 +#define IP6T_ROUTE_CONTINUE        0x01
  52 +#define IP6T_ROUTE_TEE             0x02
  53 +
  54 +#endif /*_IP6T_ROUTE_H_target*/
  55 diff -urN linux-2.6.21.1.old/net/ipv4/netfilter/ipt_ROUTE.c linux-2.6.21.1.dev/net/ipv4/netfilter/ipt_ROUTE.c
  56 --- linux-2.6.21.1.old/net/ipv4/netfilter/ipt_ROUTE.c   1970-01-01 01:00:00.000000000 +0100
  57 +++ linux-2.6.21.1.dev/net/ipv4/netfilter/ipt_ROUTE.c   2007-05-26 20:37:09.001852088 +0200
  58 @@ -0,0 +1,483 @@
  59 +/*
  60 + * This implements the ROUTE target, which enables you to setup unusual
  61 + * routes not supported by the standard kernel routing table.
  62 + *
  63 + * Copyright (C) 2002 Cedric de Launois <delaunois@info.ucl.ac.be>
  64 + *
  65 + * v 1.11 2004/11/23
  66 + *
  67 + * This software is distributed under GNU GPL v2, 1991
  68 + */
  69 +
  70 +#include <linux/module.h>
  71 +#include <linux/skbuff.h>
  72 +#include <linux/ip.h>
  73 +#include <linux/netfilter_ipv4/ip_tables.h>
  74 +#include <linux/netfilter_ipv4/ip_conntrack.h>
  75 +#include <linux/netfilter_ipv4/ipt_ROUTE.h>
  76 +#include <linux/netdevice.h>
  77 +#include <linux/route.h>
  78 +#include <linux/version.h>
  79 +#include <linux/if_arp.h>
  80 +#include <net/ip.h>
  81 +#include <net/route.h>
  82 +#include <net/icmp.h>
  83 +#include <net/checksum.h>
  84 +
  85 +#if 0
  86 +#define DEBUGP printk
  87 +#else
  88 +#define DEBUGP(format, args...)
  89 +#endif
  90 +
  91 +MODULE_LICENSE("GPL");
  92 +MODULE_AUTHOR("Cedric de Launois <delaunois@info.ucl.ac.be>");
  93 +MODULE_DESCRIPTION("iptables ROUTE target module");
  94 +
  95 +/* Try to route the packet according to the routing keys specified in
  96 + * route_info. Keys are :
  97 + *  - ifindex :
  98 + *      0 if no oif preferred,
  99 + *      otherwise set to the index of the desired oif
 100 + *  - route_info->gw :
 101 + *      0 if no gateway specified,
 102 + *      otherwise set to the next host to which the pkt must be routed
 103 + * If success, skb->dev is the output device to which the packet must
 104 + * be sent and skb->dst is not NULL
 105 + *
 106 + * RETURN: -1 if an error occured
 107 + *          1 if the packet was succesfully routed to the
 108 + *            destination desired
 109 + *          0 if the kernel routing table could not route the packet
 110 + *            according to the keys specified
 111 + */
 112 +static int route(struct sk_buff *skb,
 113 +                unsigned int ifindex,
 114 +                const struct ipt_route_target_info *route_info)
 115 +{
 116 +       int err;
 117 +       struct rtable *rt;
 118 +       struct iphdr *iph = skb->nh.iph;
 119 +       struct flowi fl = {
 120 +               .oif = ifindex,
 121 +               .nl_u = {
 122 +                       .ip4_u = {
 123 +                               .daddr = iph->daddr,
 124 +                               .saddr = 0,
 125 +                               .tos = RT_TOS(iph->tos),
 126 +                               .scope = RT_SCOPE_UNIVERSE,
 127 +                       }
 128 +               }
 129 +       };
 130 +
 131 +       /* The destination address may be overloaded by the target */
 132 +       if (route_info->gw)
 133 +               fl.fl4_dst = route_info->gw;
 134 +
 135 +       /* Trying to route the packet using the standard routing table. */
 136 +       if ((err = ip_route_output_key(&rt, &fl))) {
 137 +               if (net_ratelimit())
 138 +                       DEBUGP("ipt_ROUTE: couldn't route pkt (err: %i)",err);
 139 +               return -1;
 140 +       }
 141 +
 142 +       /* Drop old route. */
 143 +       dst_release(skb->dst);
 144 +       skb->dst = NULL;
 145 +
 146 +       /* Success if no oif specified or if the oif correspond to the
 147 +        * one desired */
 148 +       if (!ifindex || rt->u.dst.dev->ifindex == ifindex) {
 149 +               skb->dst = &rt->u.dst;
 150 +               skb->dev = skb->dst->dev;
 151 +               skb->protocol = htons(ETH_P_IP);
 152 +               return 1;
 153 +       }
 154 +
 155 +       /* The interface selected by the routing table is not the one
 156 +        * specified by the user. This may happen because the dst address
 157 +        * is one of our own addresses.
 158 +        */
 159 +       if (net_ratelimit())
 160 +               DEBUGP("ipt_ROUTE: failed to route as desired gw=%u.%u.%u.%u oif=%i (got oif=%i)\n",
 161 +                      NIPQUAD(route_info->gw), ifindex, rt->u.dst.dev->ifindex);
 162 +
 163 +       return 0;
 164 +}
 165 +
 166 +
 167 +/* Stolen from ip_finish_output2
 168 + * PRE : skb->dev is set to the device we are leaving by
 169 + *       skb->dst is not NULL
 170 + * POST: the packet is sent with the link layer header pushed
 171 + *       the packet is destroyed
 172 + */
 173 +static void ip_direct_send(struct sk_buff *skb)
 174 +{
 175 +       struct dst_entry *dst = skb->dst;
 176 +       struct hh_cache *hh = dst->hh;
 177 +       struct net_device *dev = dst->dev;
 178 +       int hh_len = LL_RESERVED_SPACE(dev);
 179 +
 180 +       /* Be paranoid, rather than too clever. */
 181 +       if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) {
 182 +               struct sk_buff *skb2;
 183 +
 184 +               skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
 185 +               if (skb2 == NULL) {
 186 +                       kfree_skb(skb);
 187 +                       return;
 188 +               }
 189 +               if (skb->sk)
 190 +                       skb_set_owner_w(skb2, skb->sk);
 191 +               kfree_skb(skb);
 192 +               skb = skb2;
 193 +       }
 194 +
 195 +       if (hh) {
 196 +               int hh_alen;
 197 +
 198 +               read_lock_bh(&hh->hh_lock);
 199 +               hh_alen = HH_DATA_ALIGN(hh->hh_len);
 200 +               memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
 201 +               read_unlock_bh(&hh->hh_lock);
 202 +               skb_push(skb, hh->hh_len);
 203 +               hh->hh_output(skb);
 204 +       } else if (dst->neighbour)
 205 +               dst->neighbour->output(skb);
 206 +       else {
 207 +               if (net_ratelimit())
 208 +                       DEBUGP(KERN_DEBUG "ipt_ROUTE: no hdr & no neighbour cache!\n");
 209 +               kfree_skb(skb);
 210 +       }
 211 +}
 212 +
 213 +
 214 +/* PRE : skb->dev is set to the device we are leaving by
 215 + * POST: - the packet is directly sent to the skb->dev device, without
 216 + *         pushing the link layer header.
 217 + *       - the packet is destroyed
 218 + */
 219 +static inline int dev_direct_send(struct sk_buff *skb)
 220 +{
 221 +       return dev_queue_xmit(skb);
 222 +}
 223 +
 224 +
 225 +static unsigned int route_oif(const struct ipt_route_target_info *route_info,
 226 +                             struct sk_buff *skb)
 227 +{
 228 +       unsigned int ifindex = 0;
 229 +       struct net_device *dev_out = NULL;
 230 +
 231 +       /* The user set the interface name to use.
 232 +        * Getting the current interface index.
 233 +        */
 234 +       if ((dev_out = dev_get_by_name(route_info->oif))) {
 235 +               ifindex = dev_out->ifindex;
 236 +       } else {
 237 +               /* Unknown interface name : packet dropped */
 238 +               if (net_ratelimit())
 239 +                       DEBUGP("ipt_ROUTE: oif interface %s not found\n", route_info->oif);
 240 +               return NF_DROP;
 241 +       }
 242 +
 243 +       /* Trying the standard way of routing packets */
 244 +       switch (route(skb, ifindex, route_info)) {
 245 +       case 1:
 246 +               dev_put(dev_out);
 247 +               if (route_info->flags & IPT_ROUTE_CONTINUE)
 248 +                       return IPT_CONTINUE;
 249 +
 250 +               ip_direct_send(skb);
 251 +               return NF_STOLEN;
 252 +
 253 +       case 0:
 254 +               /* Failed to send to oif. Trying the hard way */
 255 +               if (route_info->flags & IPT_ROUTE_CONTINUE)
 256 +                       return NF_DROP;
 257 +
 258 +               if (net_ratelimit())
 259 +                       DEBUGP("ipt_ROUTE: forcing the use of %i\n",
 260 +                              ifindex);
 261 +
 262 +               /* We have to force the use of an interface.
 263 +                * This interface must be a tunnel interface since
 264 +                * otherwise we can't guess the hw address for
 265 +                * the packet. For a tunnel interface, no hw address
 266 +                * is needed.
 267 +                */
 268 +               if ((dev_out->type != ARPHRD_TUNNEL)
 269 +                   && (dev_out->type != ARPHRD_IPGRE)) {
 270 +                       if (net_ratelimit())
 271 +                               DEBUGP("ipt_ROUTE: can't guess the hw addr !\n");
 272 +                       dev_put(dev_out);
 273 +                       return NF_DROP;
 274 +               }
 275 +
 276 +               /* Send the packet. This will also free skb
 277 +                * Do not go through the POST_ROUTING hook because
 278 +                * skb->dst is not set and because it will probably
 279 +                * get confused by the destination IP address.
 280 +                */
 281 +               skb->dev = dev_out;
 282 +               dev_direct_send(skb);
 283 +               dev_put(dev_out);
 284 +               return NF_STOLEN;
 285 +
 286 +       default:
 287 +               /* Unexpected error */
 288 +               dev_put(dev_out);
 289 +               return NF_DROP;
 290 +       }
 291 +}
 292 +
 293 +
 294 +static unsigned int route_iif(const struct ipt_route_target_info *route_info,
 295 +                             struct sk_buff *skb)
 296 +{
 297 +       struct net_device *dev_in = NULL;
 298 +
 299 +       /* Getting the current interface index. */
 300 +       if (!(dev_in = dev_get_by_name(route_info->iif))) {
 301 +               if (net_ratelimit())
 302 +                       DEBUGP("ipt_ROUTE: iif interface %s not found\n", route_info->iif);
 303 +               return NF_DROP;
 304 +       }
 305 +
 306 +       skb->dev = dev_in;
 307 +       dst_release(skb->dst);
 308 +       skb->dst = NULL;
 309 +
 310 +       netif_rx(skb);
 311 +       dev_put(dev_in);
 312 +       return NF_STOLEN;
 313 +}
 314 +
 315 +
 316 +static unsigned int route_gw(const struct ipt_route_target_info *route_info,
 317 +                            struct sk_buff *skb)
 318 +{
 319 +       if (route(skb, 0, route_info)!=1)
 320 +               return NF_DROP;
 321 +
 322 +       if (route_info->flags & IPT_ROUTE_CONTINUE)
 323 +               return IPT_CONTINUE;
 324 +
 325 +       ip_direct_send(skb);
 326 +       return NF_STOLEN;
 327 +}
 328 +
 329 +
 330 +/* To detect and deter routed packet loopback when using the --tee option,
 331 + * we take a page out of the raw.patch book: on the copied skb, we set up
 332 + * a fake ->nfct entry, pointing to the local &route_tee_track. We skip
 333 + * routing packets when we see they already have that ->nfct.
 334 + */
 335 +
 336 +static struct ip_conntrack route_tee_track;
 337 +
 338 +static unsigned int ipt_route_target(struct sk_buff **pskb,
 339 +                                    const struct net_device *in,
 340 +                                    const struct net_device *out,
 341 +                                    unsigned int hooknum,
 342 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 343 +                                    const struct xt_target *target,
 344 +#endif
 345 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 346 +                                    const void *targinfo,
 347 +                                    void *userinfo)
 348 +#else
 349 +                                    const void *targinfo)
 350 +#endif
 351 +{
 352 +       const struct ipt_route_target_info *route_info = targinfo;
 353 +       struct sk_buff *skb = *pskb;
 354 +       unsigned int res;
 355 +
 356 +       if (skb->nfct == &route_tee_track.ct_general) {
 357 +               /* Loopback - a packet we already routed, is to be
 358 +                * routed another time. Avoid that, now.
 359 +                */
 360 +               if (net_ratelimit())
 361 +                       DEBUGP(KERN_DEBUG "ipt_ROUTE: loopback - DROP!\n");
 362 +               return NF_DROP;
 363 +       }
 364 +
 365 +       /* If we are at PREROUTING or INPUT hook
 366 +        * the TTL isn't decreased by the IP stack
 367 +        */
 368 +       if (hooknum == NF_IP_PRE_ROUTING ||
 369 +           hooknum == NF_IP_LOCAL_IN) {
 370 +
 371 +               struct iphdr *iph = skb->nh.iph;
 372 +
 373 +               if (iph->ttl <= 1) {
 374 +                       struct rtable *rt;
 375 +                       struct flowi fl = {
 376 +                               .oif = 0,
 377 +                               .nl_u = {
 378 +                                       .ip4_u = {
 379 +                                               .daddr = iph->daddr,
 380 +                                               .saddr = iph->saddr,
 381 +                                               .tos = RT_TOS(iph->tos),
 382 +                                               .scope = ((iph->tos & RTO_ONLINK) ?
 383 +                                                         RT_SCOPE_LINK :
 384 +                                                         RT_SCOPE_UNIVERSE)
 385 +                                       }
 386 +                               }
 387 +                       };
 388 +
 389 +                       if (ip_route_output_key(&rt, &fl)) {
 390 +                               return NF_DROP;
 391 +                       }
 392 +
 393 +                       if (skb->dev == rt->u.dst.dev) {
 394 +                               /* Drop old route. */
 395 +                               dst_release(skb->dst);
 396 +                               skb->dst = &rt->u.dst;
 397 +
 398 +                               /* this will traverse normal stack, and
 399 +                                * thus call conntrack on the icmp packet */
 400 +                               icmp_send(skb, ICMP_TIME_EXCEEDED,
 401 +                                         ICMP_EXC_TTL, 0);
 402 +                       }
 403 +
 404 +                       return NF_DROP;
 405 +               }
 406 +
 407 +               /*
 408 +                * If we are at INPUT the checksum must be recalculated since
 409 +                * the length could change as the result of a defragmentation.
 410 +                */
 411 +               if(hooknum == NF_IP_LOCAL_IN) {
 412 +                       iph->ttl = iph->ttl - 1;
 413 +                       iph->check = 0;
 414 +                       iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
 415 +               } else {
 416 +                       ip_decrease_ttl(iph);
 417 +               }
 418 +       }
 419 +
 420 +       if ((route_info->flags & IPT_ROUTE_TEE)) {
 421 +               /*
 422 +                * Copy the *pskb, and route the copy. Will later return
 423 +                * IPT_CONTINUE for the original skb, which should continue
 424 +                * on its way as if nothing happened. The copy should be
 425 +                * independantly delivered to the ROUTE --gw.
 426 +                */
 427 +               skb = skb_copy(*pskb, GFP_ATOMIC);
 428 +               if (!skb) {
 429 +                       if (net_ratelimit())
 430 +                               DEBUGP(KERN_DEBUG "ipt_ROUTE: copy failed!\n");
 431 +                       return IPT_CONTINUE;
 432 +               }
 433 +       }
 434 +
 435 +       /* Tell conntrack to forget this packet since it may get confused
 436 +        * when a packet is leaving with dst address == our address.
 437 +        * Good idea ? Dunno. Need advice.
 438 +        *
 439 +        * NEW: mark the skb with our &route_tee_track, so we avoid looping
 440 +        * on any already routed packet.
 441 +        */
 442 +       if (!(route_info->flags & IPT_ROUTE_CONTINUE)) {
 443 +               nf_conntrack_put(skb->nfct);
 444 +               skb->nfct = &route_tee_track.ct_general;
 445 +               skb->nfctinfo = IP_CT_NEW;
 446 +               nf_conntrack_get(skb->nfct);
 447 +       }
 448 +
 449 +       if (route_info->oif[0] != '\0') {
 450 +               res = route_oif(route_info, skb);
 451 +       } else if (route_info->iif[0] != '\0') {
 452 +               res = route_iif(route_info, skb);
 453 +       } else if (route_info->gw) {
 454 +               res = route_gw(route_info, skb);
 455 +       } else {
 456 +               if (net_ratelimit())
 457 +                       DEBUGP(KERN_DEBUG "ipt_ROUTE: no parameter !\n");
 458 +               res = IPT_CONTINUE;
 459 +       }
 460 +
 461 +       if ((route_info->flags & IPT_ROUTE_TEE))
 462 +               res = IPT_CONTINUE;
 463 +
 464 +       return res;
 465 +}
 466 +
 467 +
 468 +static int ipt_route_checkentry(const char *tablename,
 469 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
 470 +                               const void *e,
 471 +#else
 472 +                               const struct ipt_ip *ip,
 473 +#endif
 474 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 475 +                               const struct xt_target *target,
 476 +#endif
 477 +                               void *targinfo,
 478 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 479 +                               unsigned int targinfosize,
 480 +#endif
 481 +                               unsigned int hook_mask)
 482 +{
 483 +       if (strcmp(tablename, "mangle") != 0) {
 484 +               printk("ipt_ROUTE: bad table `%s', use the `mangle' table.\n",
 485 +                      tablename);
 486 +               return 0;
 487 +       }
 488 +
 489 +       if (hook_mask & ~(  (1 << NF_IP_PRE_ROUTING)
 490 +                           | (1 << NF_IP_LOCAL_IN)
 491 +                           | (1 << NF_IP_FORWARD)
 492 +                           | (1 << NF_IP_LOCAL_OUT)
 493 +                           | (1 << NF_IP_POST_ROUTING))) {
 494 +               printk("ipt_ROUTE: bad hook\n");
 495 +               return 0;
 496 +       }
 497 +
 498 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 499 +       if (targinfosize != IPT_ALIGN(sizeof(struct ipt_route_target_info))) {
 500 +               printk(KERN_WARNING "ipt_ROUTE: targinfosize %u != %Zu\n",
 501 +                      targinfosize,
 502 +                      IPT_ALIGN(sizeof(struct ipt_route_target_info)));
 503 +               return 0;
 504 +       }
 505 +#endif
 506 +
 507 +       return 1;
 508 +}
 509 +
 510 +
 511 +static struct ipt_target ipt_route_reg = {
 512 +       .name = "ROUTE",
 513 +       .target = ipt_route_target,
 514 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 515 +       .targetsize = sizeof(struct ipt_route_target_info),
 516 +#endif
 517 +       .checkentry = ipt_route_checkentry,
 518 +       .me = THIS_MODULE,
 519 +};
 520 +
 521 +static int __init init(void)
 522 +{
 523 +       /* Set up fake conntrack (stolen from raw.patch):
 524 +           - to never be deleted, not in any hashes */
 525 +       atomic_set(&route_tee_track.ct_general.use, 1);
 526 +       /*  - and look it like as a confirmed connection */
 527 +       set_bit(IPS_CONFIRMED_BIT, &route_tee_track.status);
 528 +       /* Initialize fake conntrack so that NAT will skip it */
 529 +       route_tee_track.status |= IPS_NAT_DONE_MASK;
 530 +
 531 +       return xt_register_target(&ipt_route_reg);
 532 +}
 533 +
 534 +
 535 +static void __exit fini(void)
 536 +{
 537 +       xt_unregister_target(&ipt_route_reg);
 538 +}
 539 +
 540 +module_init(init);
 541 +module_exit(fini);
 542 diff -urN linux-2.6.21.1.old/net/ipv4/netfilter/Kconfig linux-2.6.21.1.dev/net/ipv4/netfilter/Kconfig
 543 --- linux-2.6.21.1.old/net/ipv4/netfilter/Kconfig       2007-05-26 20:37:08.734892672 +0200
 544 +++ linux-2.6.21.1.dev/net/ipv4/netfilter/Kconfig       2007-05-26 20:37:09.002851936 +0200
 545 @@ -817,5 +817,22 @@
 546           To compile it as a module, choose M here.  If unsure, say N.
 547
 548
 549 +config IP_NF_TARGET_ROUTE
 550 +       tristate  'ROUTE target support'
 551 +       depends on IP_NF_MANGLE
 552 +       help
 553 +         This option adds a `ROUTE' target, which enables you to setup unusual
 554 +         routes. For example, the ROUTE lets you route a received packet through
 555 +         an interface or towards a host, even if the regular destination of the
 556 +         packet is the router itself. The ROUTE target is also able to change the
 557 +         incoming interface of a packet.
 558 +
 559 +         The target can be or not a final target. It has to be used inside the
 560 +         mangle table.
 561 +
 562 +         If you want to compile it as a module, say M here and read
 563 +         Documentation/modules.txt.  The module will be called ipt_ROUTE.o.
 564 +         If unsure, say `N'.
 565 +
 566  endmenu
 567
 568 diff -urN linux-2.6.21.1.old/net/ipv4/netfilter/Makefile linux-2.6.21.1.dev/net/ipv4/netfilter/Makefile
 569 --- linux-2.6.21.1.old/net/ipv4/netfilter/Makefile      2007-05-26 20:37:08.735892520 +0200
 570 +++ linux-2.6.21.1.dev/net/ipv4/netfilter/Makefile      2007-05-26 20:37:09.002851936 +0200
 571 @@ -103,6 +103,7 @@
 572  obj-$(CONFIG_IP_NF_TARGET_IMQ) += ipt_IMQ.o
 573  obj-$(CONFIG_IP_NF_TARGET_MASQUERADE) += ipt_MASQUERADE.o
 574  obj-$(CONFIG_IP_NF_TARGET_REDIRECT) += ipt_REDIRECT.o
 575 +obj-$(CONFIG_IP_NF_TARGET_ROUTE) += ipt_ROUTE.o
 576  obj-$(CONFIG_IP_NF_TARGET_NETMAP) += ipt_NETMAP.o
 577  obj-$(CONFIG_IP_NF_TARGET_SAME) += ipt_SAME.o
 578  obj-$(CONFIG_IP_NF_NAT_SNMP_BASIC) += ip_nat_snmp_basic.o
 579 diff -urN linux-2.6.21.1.old/net/ipv6/ipv6_syms.c linux-2.6.21.1.dev/net/ipv6/ipv6_syms.c
 580 --- linux-2.6.21.1.old/net/ipv6/ipv6_syms.c     2007-04-27 23:49:26.000000000 +0200
 581 +++ linux-2.6.21.1.dev/net/ipv6/ipv6_syms.c     2007-05-26 20:37:09.002851936 +0200
 582 @@ -10,6 +10,7 @@
 583  EXPORT_SYMBOL(icmpv6_statistics);
 584  EXPORT_SYMBOL(icmpv6_err_convert);
 585  EXPORT_SYMBOL(ndisc_mc_map);
 586 +EXPORT_SYMBOL(nd_tbl);
 587  EXPORT_SYMBOL(register_inet6addr_notifier);
 588  EXPORT_SYMBOL(unregister_inet6addr_notifier);
 589  EXPORT_SYMBOL(ip6_route_output);
 590 diff -urN linux-2.6.21.1.old/net/ipv6/netfilter/ip6t_ROUTE.c linux-2.6.21.1.dev/net/ipv6/netfilter/ip6t_ROUTE.c
 591 --- linux-2.6.21.1.old/net/ipv6/netfilter/ip6t_ROUTE.c  1970-01-01 01:00:00.000000000 +0100
 592 +++ linux-2.6.21.1.dev/net/ipv6/netfilter/ip6t_ROUTE.c  2007-05-26 20:37:09.003851784 +0200
 593 @@ -0,0 +1,330 @@
 594 +/*
 595 + * This implements the ROUTE v6 target, which enables you to setup unusual
 596 + * routes not supported by the standard kernel routing table.
 597 + *
 598 + * Copyright (C) 2003 Cedric de Launois <delaunois@info.ucl.ac.be>
 599 + *
 600 + * v 1.1 2004/11/23
 601 + *
 602 + * This software is distributed under GNU GPL v2, 1991
 603 + */
 604 +
 605 +#include <linux/module.h>
 606 +#include <linux/skbuff.h>
 607 +#include <linux/ipv6.h>
 608 +#include <linux/netfilter_ipv6/ip6_tables.h>
 609 +#include <linux/netfilter_ipv6/ip6t_ROUTE.h>
 610 +#include <linux/netdevice.h>
 611 +#include <linux/version.h>
 612 +#include <net/ipv6.h>
 613 +#include <net/ndisc.h>
 614 +#include <net/ip6_route.h>
 615 +#include <linux/icmpv6.h>
 616 +
 617 +#if 1
 618 +#define DEBUGP printk
 619 +#else
 620 +#define DEBUGP(format, args...)
 621 +#endif
 622 +
 623 +#define NIP6(addr) \
 624 +       ntohs((addr).s6_addr16[0]), \
 625 +       ntohs((addr).s6_addr16[1]), \
 626 +       ntohs((addr).s6_addr16[2]), \
 627 +       ntohs((addr).s6_addr16[3]), \
 628 +       ntohs((addr).s6_addr16[4]), \
 629 +       ntohs((addr).s6_addr16[5]), \
 630 +       ntohs((addr).s6_addr16[6]), \
 631 +       ntohs((addr).s6_addr16[7])
 632 +
 633 +/* Route the packet according to the routing keys specified in
 634 + * route_info. Keys are :
 635 + *  - ifindex :
 636 + *      0 if no oif preferred,
 637 + *      otherwise set to the index of the desired oif
 638 + *  - route_info->gw :
 639 + *      0 if no gateway specified,
 640 + *      otherwise set to the next host to which the pkt must be routed
 641 + * If success, skb->dev is the output device to which the packet must
 642 + * be sent and skb->dst is not NULL
 643 + *
 644 + * RETURN:  1 if the packet was succesfully routed to the
 645 + *            destination desired
 646 + *          0 if the kernel routing table could not route the packet
 647 + *            according to the keys specified
 648 + */
 649 +static int
 650 +route6(struct sk_buff *skb,
 651 +       unsigned int ifindex,
 652 +       const struct ip6t_route_target_info *route_info)
 653 +{
 654 +       struct rt6_info *rt = NULL;
 655 +       struct ipv6hdr *ipv6h = skb->nh.ipv6h;
 656 +       struct in6_addr *gw = (struct in6_addr*)&route_info->gw;
 657 +
 658 +       DEBUGP("ip6t_ROUTE: called with: ");
 659 +       DEBUGP("DST=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ipv6h->daddr));
 660 +       DEBUGP("GATEWAY=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(*gw));
 661 +       DEBUGP("OUT=%s\n", route_info->oif);
 662 +
 663 +       if (ipv6_addr_any(gw))
 664 +               rt = rt6_lookup(&ipv6h->daddr, &ipv6h->saddr, ifindex, 1);
 665 +       else
 666 +               rt = rt6_lookup(gw, &ipv6h->saddr, ifindex, 1);
 667 +
 668 +       if (!rt)
 669 +               goto no_route;
 670 +
 671 +       DEBUGP("ip6t_ROUTE: routing gives: ");
 672 +       DEBUGP("DST=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(rt->rt6i_dst.addr));
 673 +       DEBUGP("GATEWAY=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(rt->rt6i_gateway));
 674 +       DEBUGP("OUT=%s\n", rt->rt6i_dev->name);
 675 +
 676 +       if (ifindex && rt->rt6i_dev->ifindex!=ifindex)
 677 +               goto wrong_route;
 678 +
 679 +       if (!rt->rt6i_nexthop) {
 680 +               DEBUGP("ip6t_ROUTE: discovering neighbour\n");
 681 +               rt->rt6i_nexthop = ndisc_get_neigh(rt->rt6i_dev, &rt->rt6i_dst.addr);
 682 +       }
 683 +
 684 +       /* Drop old route. */
 685 +       dst_release(skb->dst);
 686 +       skb->dst = &rt->u.dst;
 687 +       skb->dev = rt->rt6i_dev;
 688 +       return 1;
 689 +
 690 + wrong_route:
 691 +       dst_release(&rt->u.dst);
 692 + no_route:
 693 +       if (!net_ratelimit())
 694 +               return 0;
 695 +
 696 +       printk("ip6t_ROUTE: no explicit route found ");
 697 +       if (ifindex)
 698 +               printk("via interface %s ", route_info->oif);
 699 +       if (!ipv6_addr_any(gw))
 700 +               printk("via gateway %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", NIP6(*gw));
 701 +       printk("\n");
 702 +       return 0;
 703 +}
 704 +
 705 +
 706 +/* Stolen from ip6_output_finish
 707 + * PRE : skb->dev is set to the device we are leaving by
 708 + *       skb->dst is not NULL
 709 + * POST: the packet is sent with the link layer header pushed
 710 + *       the packet is destroyed
 711 + */
 712 +static void ip_direct_send(struct sk_buff *skb)
 713 +{
 714 +       struct dst_entry *dst = skb->dst;
 715 +       struct hh_cache *hh = dst->hh;
 716 +
 717 +       if (hh) {
 718 +               read_lock_bh(&hh->hh_lock);
 719 +               memcpy(skb->data - 16, hh->hh_data, 16);
 720 +               read_unlock_bh(&hh->hh_lock);
 721 +               skb_push(skb, hh->hh_len);
 722 +               hh->hh_output(skb);
 723 +       } else if (dst->neighbour)
 724 +               dst->neighbour->output(skb);
 725 +       else {
 726 +               if (net_ratelimit())
 727 +                       DEBUGP(KERN_DEBUG "ip6t_ROUTE: no hdr & no neighbour cache!\n");
 728 +               kfree_skb(skb);
 729 +       }
 730 +}
 731 +
 732 +
 733 +static unsigned int
 734 +route6_oif(const struct ip6t_route_target_info *route_info,
 735 +          struct sk_buff *skb)
 736 +{
 737 +       unsigned int ifindex = 0;
 738 +       struct net_device *dev_out = NULL;
 739 +
 740 +       /* The user set the interface name to use.
 741 +        * Getting the current interface index.
 742 +        */
 743 +       if ((dev_out = dev_get_by_name(route_info->oif))) {
 744 +               ifindex = dev_out->ifindex;
 745 +       } else {
 746 +               /* Unknown interface name : packet dropped */
 747 +               if (net_ratelimit())
 748 +                       DEBUGP("ip6t_ROUTE: oif interface %s not found\n", route_info->oif);
 749 +
 750 +               if (route_info->flags & IP6T_ROUTE_CONTINUE)
 751 +                       return IP6T_CONTINUE;
 752 +               else
 753 +                       return NF_DROP;
 754 +       }
 755 +
 756 +       /* Trying the standard way of routing packets */
 757 +       if (route6(skb, ifindex, route_info)) {
 758 +               dev_put(dev_out);
 759 +               if (route_info->flags & IP6T_ROUTE_CONTINUE)
 760 +                       return IP6T_CONTINUE;
 761 +
 762 +               ip_direct_send(skb);
 763 +               return NF_STOLEN;
 764 +       } else
 765 +               return NF_DROP;
 766 +}
 767 +
 768 +
 769 +static unsigned int
 770 +route6_gw(const struct ip6t_route_target_info *route_info,
 771 +         struct sk_buff *skb)
 772 +{
 773 +       if (route6(skb, 0, route_info)) {
 774 +               if (route_info->flags & IP6T_ROUTE_CONTINUE)
 775 +                       return IP6T_CONTINUE;
 776 +
 777 +               ip_direct_send(skb);
 778 +               return NF_STOLEN;
 779 +       } else
 780 +               return NF_DROP;
 781 +}
 782 +
 783 +
 784 +static unsigned int
 785 +ip6t_route_target(struct sk_buff **pskb,
 786 +                 const struct net_device *in,
 787 +                 const struct net_device *out,
 788 +                 unsigned int hooknum,
 789 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 790 +                 const struct xt_target *target,
 791 +#endif
 792 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 793 +                 const void *targinfo,
 794 +                 void *userinfo)
 795 +#else
 796 +                 const void *targinfo)
 797 +#endif
 798 +{
 799 +       const struct ip6t_route_target_info *route_info = targinfo;
 800 +       struct sk_buff *skb = *pskb;
 801 +       struct in6_addr *gw = (struct in6_addr*)&route_info->gw;
 802 +       unsigned int res;
 803 +
 804 +       if (route_info->flags & IP6T_ROUTE_CONTINUE)
 805 +               goto do_it;
 806 +
 807 +       /* If we are at PREROUTING or INPUT hook
 808 +        * the TTL isn't decreased by the IP stack
 809 +        */
 810 +       if (hooknum == NF_IP6_PRE_ROUTING ||
 811 +           hooknum == NF_IP6_LOCAL_IN) {
 812 +
 813 +               struct ipv6hdr *ipv6h = skb->nh.ipv6h;
 814 +
 815 +               if (ipv6h->hop_limit <= 1) {
 816 +                       /* Force OUTPUT device used as source address */
 817 +                       skb->dev = skb->dst->dev;
 818 +
 819 +                       icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 820 +                                   ICMPV6_EXC_HOPLIMIT, 0, skb->dev);
 821 +
 822 +                       return NF_DROP;
 823 +               }
 824 +
 825 +               ipv6h->hop_limit--;
 826 +       }
 827 +
 828 +       if ((route_info->flags & IP6T_ROUTE_TEE)) {
 829 +               /*
 830 +                * Copy the *pskb, and route the copy. Will later return
 831 +                * IP6T_CONTINUE for the original skb, which should continue
 832 +                * on its way as if nothing happened. The copy should be
 833 +                * independantly delivered to the ROUTE --gw.
 834 +                */
 835 +               skb = skb_copy(*pskb, GFP_ATOMIC);
 836 +               if (!skb) {
 837 +                       if (net_ratelimit())
 838 +                               DEBUGP(KERN_DEBUG "ip6t_ROUTE: copy failed!\n");
 839 +                       return IP6T_CONTINUE;
 840 +               }
 841 +       }
 842 +
 843 +do_it:
 844 +       if (route_info->oif[0]) {
 845 +               res = route6_oif(route_info, skb);
 846 +       } else if (!ipv6_addr_any(gw)) {
 847 +               res = route6_gw(route_info, skb);
 848 +       } else {
 849 +               if (net_ratelimit())
 850 +                       DEBUGP(KERN_DEBUG "ip6t_ROUTE: no parameter !\n");
 851 +               res = IP6T_CONTINUE;
 852 +       }
 853 +
 854 +       if ((route_info->flags & IP6T_ROUTE_TEE))
 855 +               res = IP6T_CONTINUE;
 856 +
 857 +       return res;
 858 +}
 859 +
 860 +
 861 +static int
 862 +ip6t_route_checkentry(const char *tablename,
 863 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
 864 +                     const void *entry,
 865 +#else
 866 +                     const struct ip6t_entry *entry
 867 +#endif
 868 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 869 +                     const struct xt_target *target,
 870 +#endif
 871 +                     void *targinfo,
 872 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 873 +                     unsigned int targinfosize,
 874 +#endif
 875 +                     unsigned int hook_mask)
 876 +{
 877 +       if (strcmp(tablename, "mangle") != 0) {
 878 +               printk("ip6t_ROUTE: can only be called from \"mangle\" table.\n");
 879 +               return 0;
 880 +       }
 881 +
 882 +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 883 +       if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_route_target_info))) {
 884 +               printk(KERN_WARNING "ip6t_ROUTE: targinfosize %u != %Zu\n",
 885 +                      targinfosize,
 886 +                      IP6T_ALIGN(sizeof(struct ip6t_route_target_info)));
 887 +               return 0;
 888 +       }
 889 +#endif
 890 +
 891 +       return 1;
 892 +}
 893 +
 894 +
 895 +static struct ip6t_target ip6t_route_reg = {
 896 +       .name       = "ROUTE",
 897 +       .target     = ip6t_route_target,
 898 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
 899 +       .targetsize = sizeof(struct ip6t_route_target_info),
 900 +#endif
 901 +       .checkentry = ip6t_route_checkentry,
 902 +       .me         = THIS_MODULE
 903 +};
 904 +
 905 +
 906 +static int __init init(void)
 907 +{
 908 +       printk(KERN_DEBUG "registering ipv6 ROUTE target\n");
 909 +       if (xt_register_target(&ip6t_route_reg))
 910 +               return -EINVAL;
 911 +
 912 +       return 0;
 913 +}
 914 +
 915 +
 916 +static void __exit fini(void)
 917 +{
 918 +       xt_unregister_target(&ip6t_route_reg);
 919 +}
 920 +
 921 +module_init(init);
 922 +module_exit(fini);
 923 +MODULE_LICENSE("GPL");
 924 diff -urN linux-2.6.21.1.old/net/ipv6/netfilter/Kconfig linux-2.6.21.1.dev/net/ipv6/netfilter/Kconfig
 925 --- linux-2.6.21.1.old/net/ipv6/netfilter/Kconfig       2007-05-26 20:37:08.809881272 +0200
 926 +++ linux-2.6.21.1.dev/net/ipv6/netfilter/Kconfig       2007-05-26 20:37:09.003851784 +0200
 927 @@ -209,5 +209,18 @@
 928           If you want to compile it as a module, say M here and read
 929           <file:Documentation/modules.txt>.  If unsure, say `N'.
 930
 931 +config IP6_NF_TARGET_ROUTE
 932 +       tristate 'ROUTE target support'
 933 +       depends on IP6_NF_MANGLE
 934 +       help
 935 +         This option adds a `ROUTE' target, which enables you to setup unusual
 936 +         routes. The ROUTE target is also able to change the incoming interface
 937 +         of a packet.
 938 +
 939 +         The target can be or not a final target. It has to be used inside the
 940 +         mangle table.
 941 +
 942 +         Not working as a module.
 943 +
 944  endmenu
 945
 946 diff -urN linux-2.6.21.1.old/net/ipv6/netfilter/Makefile linux-2.6.21.1.dev/net/ipv6/netfilter/Makefile
 947 --- linux-2.6.21.1.old/net/ipv6/netfilter/Makefile      2007-05-26 20:37:08.809881272 +0200
 948 +++ linux-2.6.21.1.dev/net/ipv6/netfilter/Makefile      2007-05-26 20:37:09.003851784 +0200
 949 @@ -20,6 +20,7 @@
 950  obj-$(CONFIG_IP6_NF_RAW) += ip6table_raw.o
 951  obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o
 952  obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
 953 +obj-$(CONFIG_IP6_NF_TARGET_ROUTE) += ip6t_ROUTE.o
 954  obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o
 955
 956  # objects for l3 independent conntrack