target/linux/generic-2.4/patches/623-netfilter_ip6t_reject.patch

   1 Index: linux-2.4.35.4/net/ipv6/netfilter/ip6t_REJECT.c
   2 ===================================================================
   3 --- /dev/null
   4 +++ linux-2.4.35.4/net/ipv6/netfilter/ip6t_REJECT.c
   5 @@ -0,0 +1,301 @@
   6 +/*
   7 + * This is a module which is used for rejecting packets.
   8 + *     Added support for customized reject packets (Jozsef Kadlecsik).
   9 + * Sun 12 Nov 2000
  10 + *     Port to IPv6 / ip6tables (Harald Welte <laforge@gnumonks.org>)
  11 + */
  12 +#include <linux/config.h>
  13 +#include <linux/module.h>
  14 +#include <linux/skbuff.h>
  15 +#include <linux/icmpv6.h>
  16 +#include <net/tcp.h>
  17 +#include <net/ipv6.h>
  18 +#include <net/ip6_fib.h>
  19 +#include <net/ip6_route.h>
  20 +#include <linux/netfilter_ipv6/ip6_tables.h>
  21 +#include <linux/netfilter_ipv6/ip6t_REJECT.h>
  22 +
  23 +#if 1
  24 +#define DEBUGP printk
  25 +#else
  26 +#define DEBUGP(format, args...)
  27 +#endif
  28 +
  29 +#if 0
  30 +/* Send RST reply */
  31 +static void send_reset(struct sk_buff *oldskb)
  32 +{
  33 +       struct sk_buff *nskb;
  34 +       struct tcphdr *otcph, *tcph;
  35 +       struct rtable *rt;
  36 +       unsigned int otcplen;
  37 +       int needs_ack;
  38 +
  39 +       /* IP header checks: fragment, too short. */
  40 +       if (oldskb->nh.iph->frag_off & htons(IP_OFFSET)
  41 +           || oldskb->len < (oldskb->nh.iph->ihl<<2) + sizeof(struct tcphdr))
  42 +               return;
  43 +
  44 +       otcph = (struct tcphdr *)((u_int32_t*)oldskb->nh.iph + oldskb->nh.iph->ihl);
  45 +       otcplen = oldskb->len - oldskb->nh.iph->ihl*4;
  46 +
  47 +       /* No RST for RST. */
  48 +       if (otcph->rst)
  49 +               return;
  50 +
  51 +       /* Check checksum. */
  52 +       if (tcp_v4_check(otcph, otcplen, oldskb->nh.iph->saddr,
  53 +                        oldskb->nh.iph->daddr,
  54 +                        csum_partial((char *)otcph, otcplen, 0)) != 0)
  55 +               return;
  56 +
  57 +       /* Copy skb (even if skb is about to be dropped, we can't just
  58 +           clone it because there may be other things, such as tcpdump,
  59 +           interested in it) */
  60 +       nskb = skb_copy(oldskb, GFP_ATOMIC);
  61 +       if (!nskb)
  62 +               return;
  63 +
  64 +       /* This packet will not be the same as the other: clear nf fields */
  65 +       nf_conntrack_put(nskb->nfct);
  66 +       nskb->nfct = NULL;
  67 +       nskb->nfcache = 0;
  68 +#ifdef CONFIG_NETFILTER_DEBUG
  69 +       nskb->nf_debug = 0;
  70 +#endif
  71 +
  72 +       tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);
  73 +
  74 +       nskb->nh.iph->daddr = xchg(&nskb->nh.iph->saddr, nskb->nh.iph->daddr);
  75 +       tcph->source = xchg(&tcph->dest, tcph->source);
  76 +
  77 +       /* Truncate to length (no data) */
  78 +       tcph->doff = sizeof(struct tcphdr)/4;
  79 +       skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
  80 +       nskb->nh.iph->tot_len = htons(nskb->len);
  81 +
  82 +       if (tcph->ack) {
  83 +               needs_ack = 0;
  84 +               tcph->seq = otcph->ack_seq;
  85 +               tcph->ack_seq = 0;
  86 +       } else {
  87 +               needs_ack = 1;
  88 +               tcph->ack_seq = htonl(ntohl(otcph->seq) + otcph->syn + otcph->fin
  89 +                                     + otcplen - (otcph->doff<<2));
  90 +               tcph->seq = 0;
  91 +       }
  92 +
  93 +       /* Reset flags */
  94 +       ((u_int8_t *)tcph)[13] = 0;
  95 +       tcph->rst = 1;
  96 +       tcph->ack = needs_ack;
  97 +
  98 +       tcph->window = 0;
  99 +       tcph->urg_ptr = 0;
 100 +
 101 +       /* Adjust TCP checksum */
 102 +       tcph->check = 0;
 103 +       tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
 104 +                                  nskb->nh.iph->saddr,
 105 +                                  nskb->nh.iph->daddr,
 106 +                                  csum_partial((char *)tcph,
 107 +                                               sizeof(struct tcphdr), 0));
 108 +
 109 +       /* Adjust IP TTL, DF */
 110 +       nskb->nh.iph->ttl = MAXTTL;
 111 +       /* Set DF, id = 0 */
 112 +       nskb->nh.iph->frag_off = htons(IP_DF);
 113 +       nskb->nh.iph->id = 0;
 114 +
 115 +       /* Adjust IP checksum */
 116 +       nskb->nh.iph->check = 0;
 117 +       nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph,
 118 +                                          nskb->nh.iph->ihl);
 119 +
 120 +       /* Routing */
 121 +       if (ip_route_output(&rt, nskb->nh.iph->daddr, nskb->nh.iph->saddr,
 122 +                           RT_TOS(nskb->nh.iph->tos) | RTO_CONN,
 123 +                           0) != 0)
 124 +               goto free_nskb;
 125 +
 126 +       dst_release(nskb->dst);
 127 +       nskb->dst = &rt->u.dst;
 128 +
 129 +       /* "Never happens" */
 130 +       if (nskb->len > nskb->dst->pmtu)
 131 +               goto free_nskb;
 132 +
 133 +       NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
 134 +               ip_finish_output);
 135 +       return;
 136 +
 137 + free_nskb:
 138 +       kfree_skb(nskb);
 139 +}
 140 +#endif
 141 +
 142 +static unsigned int reject6_target(struct sk_buff **pskb,
 143 +                          unsigned int hooknum,
 144 +                          const struct net_device *in,
 145 +                          const struct net_device *out,
 146 +                          const void *targinfo,
 147 +                          void *userinfo)
 148 +{
 149 +       const struct ip6t_reject_info *reject = targinfo;
 150 +       struct sk_buff *skb2 = NULL;
 151 +       struct rt6_info *rt6i;
 152 +       struct net_device odev;
 153 +
 154 +       if (!out) {
 155 +               skb2 = skb_clone(*pskb, GFP_ATOMIC);
 156 +               if (skb2 == NULL) {
 157 +                       return NF_DROP;
 158 +               }
 159 +               dst_release(skb2->dst);
 160 +               skb2->dst = NULL;
 161 +
 162 +               rt6i = rt6_lookup(&skb2->nh.ipv6h->saddr, NULL, 0, 0);
 163 +               if (rt6i && rt6i->rt6i_dev) {
 164 +                       skb2->dev = rt6i->rt6i_dev;
 165 +                       rt6i = rt6_lookup(&skb2->nh.ipv6h->daddr, &skb2->nh.ipv6h->saddr, 0, 0);
 166 +               }
 167 +               memcpy(&odev, skb2->dev, sizeof(odev)); /* XXX 'out' has 'const' qualifier... */
 168 +       } else {
 169 +               memcpy(&odev, out, sizeof(odev));
 170 +       }
 171 +
 172 +       printk(KERN_DEBUG "%s: medium point\n", __FUNCTION__);
 173 +       /* WARNING: This code causes reentry within ip6tables.
 174 +          This means that the ip6tables jump stack is now crap.  We
 175 +          must return an absolute verdict. --RR */
 176 +       DEBUGP("REJECTv6: calling icmpv6_send\n");
 177 +       switch (reject->with) {
 178 +       case IP6T_ICMP6_NO_ROUTE:
 179 +               icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_NOROUTE, 0, &odev);
 180 +               break;
 181 +       case IP6T_ICMP6_ADM_PROHIBITED:
 182 +               icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_ADM_PROHIBITED, 0, &odev);
 183 +               break;
 184 +       case IP6T_ICMP6_NOT_NEIGHBOUR:
 185 +               icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_NOT_NEIGHBOUR, 0, &odev);
 186 +               break;
 187 +       case IP6T_ICMP6_ADDR_UNREACH:
 188 +               icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0, &odev);
 189 +               break;
 190 +       case IP6T_ICMP6_PORT_UNREACH:
 191 +               icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0, &odev);
 192 +               break;
 193 +#if 0
 194 +       case IPT_ICMP_ECHOREPLY: {
 195 +               struct icmp6hdr *icmph  = (struct icmphdr *)
 196 +                       ((u_int32_t *)(*pskb)->nh.iph + (*pskb)->nh.iph->ihl);
 197 +               unsigned int datalen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4;
 198 +
 199 +               /* Not non-head frags, or truncated */
 200 +               if (((ntohs((*pskb)->nh.iph->frag_off) & IP_OFFSET) == 0)
 201 +                   && datalen >= 4) {
 202 +                       /* Usually I don't like cut & pasting code,
 203 +                           but dammit, my party is starting in 45
 204 +                           mins! --RR */
 205 +                       struct icmp_bxm icmp_param;
 206 +
 207 +                       icmp_param.icmph=*icmph;
 208 +                       icmp_param.icmph.type=ICMP_ECHOREPLY;
 209 +                       icmp_param.data_ptr=(icmph+1);
 210 +                       icmp_param.data_len=datalen;
 211 +                       icmp_reply(&icmp_param, *pskb);
 212 +               }
 213 +       }
 214 +       break;
 215 +       case IPT_TCP_RESET:
 216 +               send_reset(*pskb);
 217 +               break;
 218 +#endif
 219 +       default:
 220 +               printk(KERN_WARNING "REJECTv6: case %u not handled yet\n", reject->with);
 221 +               break;
 222 +       }
 223 +
 224 +       if (skb2) kfree_skb(skb2);
 225 +
 226 +       return NF_DROP;
 227 +}
 228 +
 229 +static inline int find_ping_match(const struct ip6t_entry_match *m)
 230 +{
 231 +       const struct ip6t_icmp *icmpinfo = (const struct ip6t_icmp *)m->data;
 232 +
 233 +       if (strcmp(m->u.kernel.match->name, "icmp6") == 0
 234 +           && icmpinfo->type == ICMPV6_ECHO_REQUEST
 235 +           && !(icmpinfo->invflags & IP6T_ICMP_INV))
 236 +               return 1;
 237 +
 238 +       return 0;
 239 +}
 240 +
 241 +static int check(const char *tablename,
 242 +                const struct ip6t_entry *e,
 243 +                void *targinfo,
 244 +                unsigned int targinfosize,
 245 +                unsigned int hook_mask)
 246 +{
 247 +       const struct ip6t_reject_info *rejinfo = targinfo;
 248 +
 249 +       if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_reject_info))) {
 250 +               DEBUGP("REJECTv6: targinfosize %u != 0\n", targinfosize);
 251 +               return 0;
 252 +       }
 253 +
 254 +       /* Only allow these for packet filtering. */
 255 +       if (strcmp(tablename, "filter") != 0) {
 256 +               DEBUGP("REJECTv6: bad table `%s'.\n", tablename);
 257 +               return 0;
 258 +       }
 259 +       if ((hook_mask & ~((1 << NF_IP6_LOCAL_IN)
 260 +                          | (1 << NF_IP6_FORWARD)
 261 +                          | (1 << NF_IP6_LOCAL_OUT))) != 0) {
 262 +               DEBUGP("REJECTv6: bad hook mask %X\n", hook_mask);
 263 +               return 0;
 264 +       }
 265 +
 266 +       if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
 267 +               /* Must specify that it's an ICMP ping packet. */
 268 +               if (e->ipv6.proto != IPPROTO_ICMPV6
 269 +                   || (e->ipv6.invflags & IP6T_INV_PROTO)) {
 270 +                       DEBUGP("REJECTv6: ECHOREPLY illegal for non-icmp\n");
 271 +                       return 0;
 272 +               }
 273 +               /* Must contain ICMP match. */
 274 +               if (IP6T_MATCH_ITERATE(e, find_ping_match) == 0) {
 275 +                       DEBUGP("REJECTv6: ECHOREPLY illegal for non-ping\n");
 276 +                       return 0;
 277 +               }
 278 +       } else if (rejinfo->with == IP6T_TCP_RESET) {
 279 +               /* Must specify that it's a TCP packet */
 280 +               if (e->ipv6.proto != IPPROTO_TCP
 281 +                   || (e->ipv6.invflags & IP6T_INV_PROTO)) {
 282 +                       DEBUGP("REJECTv6: TCP_RESET illegal for non-tcp\n");
 283 +                       return 0;
 284 +               }
 285 +       }
 286 +
 287 +       return 1;
 288 +}
 289 +
 290 +static struct ip6t_target ip6t_reject_reg
 291 += { { NULL, NULL }, "REJECT", reject6_target, check, NULL, THIS_MODULE };
 292 +
 293 +static int __init init(void)
 294 +{
 295 +       if (ip6t_register_target(&ip6t_reject_reg))
 296 +               return -EINVAL;
 297 +       return 0;
 298 +}
 299 +
 300 +static void __exit fini(void)
 301 +{
 302 +       ip6t_unregister_target(&ip6t_reject_reg);
 303 +}
 304 +
 305 +module_init(init);
 306 +module_exit(fini);
 307 Index: linux-2.4.35.4/include/linux/netfilter_ipv6/ip6t_REJECT.h
 308 ===================================================================
 309 --- linux-2.4.35.4.orig/include/linux/netfilter_ipv6/ip6t_REJECT.h
 310 +++ linux-2.4.35.4/include/linux/netfilter_ipv6/ip6t_REJECT.h
 311 @@ -2,15 +2,17 @@
 312  #define _IP6T_REJECT_H
 313
 314  enum ip6t_reject_with {
 315 -       IP6T_ICMP_NET_UNREACHABLE,
 316 -       IP6T_ICMP_HOST_UNREACHABLE,
 317 -       IP6T_ICMP_PROT_UNREACHABLE,
 318 -       IP6T_ICMP_PORT_UNREACHABLE,
 319 -       IP6T_ICMP_ECHOREPLY
 320 +       IP6T_ICMP6_NO_ROUTE,
 321 +       IP6T_ICMP6_ADM_PROHIBITED,
 322 +       IP6T_ICMP6_NOT_NEIGHBOUR,
 323 +       IP6T_ICMP6_ADDR_UNREACH,
 324 +       IP6T_ICMP6_PORT_UNREACH,
 325 +       IP6T_ICMP6_ECHOREPLY,
 326 +       IP6T_TCP_RESET
 327  };
 328
 329  struct ip6t_reject_info {
 330         enum ip6t_reject_with with;      /* reject type */
 331  };
 332
 333 -#endif /*_IPT_REJECT_H*/
 334 +#endif /*_IP6T_REJECT_H*/
 335 Index: linux-2.4.35.4/net/ipv6/netfilter/Makefile
 336 ===================================================================
 337 --- linux-2.4.35.4.orig/net/ipv6/netfilter/Makefile
 338 +++ linux-2.4.35.4/net/ipv6/netfilter/Makefile
 339 @@ -34,5 +34,7 @@ obj-$(CONFIG_IP6_NF_QUEUE) += ip6_queue.
 340  obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o
 341  obj-$(CONFIG_IP6_NF_MATCH_RANDOM) += ip6t_random.o
 342  obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o
 343 +obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
 344 +
 345
 346  include $(TOPDIR)/Rules.make
 347 Index: linux-2.4.35.4/net/ipv6/netfilter/Config.in
 348 ===================================================================
 349 --- linux-2.4.35.4.orig/net/ipv6/netfilter/Config.in
 350 +++ linux-2.4.35.4/net/ipv6/netfilter/Config.in
 351 @@ -61,6 +61,9 @@ if [ "$CONFIG_IP6_NF_IPTABLES" != "n" ];
 352    if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then
 353      dep_tristate '    LOG target support' CONFIG_IP6_NF_TARGET_LOG $CONFIG_IP6_NF_FILTER
 354    fi
 355 +  if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then
 356 +    dep_tristate '    REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER
 357 +  fi
 358
 359  #  if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then
 360  #    dep_tristate '    REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER