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

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