sys/net/ip6fw/ip6_fw.c

   1 /*      $FreeBSD: src/sys/netinet6/ip6_fw.c,v 1.2.2.10 2003/08/03 17:52:54 ume Exp $    */
   2 /*      $DragonFly: src/sys/net/ip6fw/ip6_fw.c,v 1.11 2004/12/28 22:20:53 hsu Exp $     */
   3 /*      $KAME: ip6_fw.c,v 1.21 2001/01/24 01:25:32 itojun Exp $ */
   4
   5 /*
   6  * Copyright (C) 1998, 1999, 2000 and 2001 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Copyright (c) 1993 Daniel Boulet
  36  * Copyright (c) 1994 Ugen J.S.Antsilevich
  37  * Copyright (c) 1996 Alex Nash
  38  *
  39  * Redistribution and use in source forms, with and without modification,
  40  * are permitted provided that this entire comment appears intact.
  41  *
  42  * Redistribution in binary form may occur without any restrictions.
  43  * Obviously, it would be nice if you gave credit where credit is due
  44  * but requiring it would be too onerous.
  45  *
  46  * This software is provided ``AS IS'' without any warranties of any kind.
  47  */
  48
  49 /*
  50  * Implement IPv6 packet firewall
  51  */
  52
  53 #if !defined(KLD_MODULE)
  54 #include "opt_ip6fw.h"
  55 #include "opt_inet.h"
  56 #include "opt_inet6.h"
  57 #endif
  58
  59 #ifdef IP6DIVERT
  60 #error "NOT SUPPORTED IPV6 DIVERT"
  61 #endif
  62 #ifdef IP6FW_DIVERT_RESTART
  63 #error "NOT SUPPORTED IPV6 DIVERT"
  64 #endif
  65
  66 #include <sys/param.h>
  67 #include <sys/systm.h>
  68 #include <sys/malloc.h>
  69 #include <sys/mbuf.h>
  70 #include <sys/queue.h>
  71 #include <sys/kernel.h>
  72 #include <sys/socket.h>
  73 #include <sys/socketvar.h>
  74 #include <sys/syslog.h>
  75 #include <sys/time.h>
  76 #include <net/if.h>
  77 #include <net/route.h>
  78 #include <netinet/in_systm.h>
  79 #include <netinet/in.h>
  80 #include <netinet/ip.h>
  81
  82 #include <netinet/ip6.h>
  83 #include <netinet6/ip6_var.h>
  84 #include <netinet6/in6_var.h>
  85 #include <netinet/icmp6.h>
  86
  87 #include <netinet/in_pcb.h>
  88
  89 #include "ip6_fw.h"
  90 #include <netinet/ip_var.h>
  91 #include <netinet/tcp.h>
  92 #include <netinet/tcp_seq.h>
  93 #include <netinet/tcp_timer.h>
  94 #include <netinet/tcp_var.h>
  95 #include <netinet/udp.h>
  96
  97 #include <sys/sysctl.h>
  98
  99 #include <net/net_osdep.h>
 100
 101 MALLOC_DEFINE(M_IP6FW, "Ip6Fw/Ip6Acct", "Ip6Fw/Ip6Acct chain's");
 102
 103 static int fw6_debug = 1;
 104 #ifdef IPV6FIREWALL_VERBOSE
 105 static int fw6_verbose = 1;
 106 #else
 107 static int fw6_verbose = 0;
 108 #endif
 109 #ifdef IPV6FIREWALL_VERBOSE_LIMIT
 110 static int fw6_verbose_limit = IPV6FIREWALL_VERBOSE_LIMIT;
 111 #else
 112 static int fw6_verbose_limit = 0;
 113 #endif
 114
 115 LIST_HEAD (ip6_fw_head, ip6_fw_chain) ip6_fw_chain;
 116
 117 #ifdef SYSCTL_NODE
 118 SYSCTL_DECL(_net_inet6_ip6);
 119 SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
 120 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, enable, CTLFLAG_RW,
 121         &ip6_fw_enable, 0, "Enable ip6fw");
 122 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, debug, CTLFLAG_RW, &fw6_debug, 0, "");
 123 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, verbose, CTLFLAG_RW, &fw6_verbose, 0, "");
 124 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, &fw6_verbose_limit, 0, "");
 125 #endif
 126
 127 #define dprintf(a)      do {                                            \
 128                                 if (fw6_debug)                          \
 129                                         printf a;                       \
 130                         } while (0)
 131 #define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
 132
 133 static int      add_entry6 (struct ip6_fw_head *chainptr, struct ip6_fw *frwl);
 134 static int      del_entry6 (struct ip6_fw_head *chainptr, u_short number);
 135 static int      zero_entry6 (struct mbuf *m);
 136 static struct ip6_fw *check_ip6fw_struct (struct ip6_fw *m);
 137 static struct ip6_fw *check_ip6fw_mbuf (struct mbuf *fw);
 138 static int      ip6opts_match (struct ip6_hdr **ip6, struct ip6_fw *f,
 139                                    struct mbuf **m,
 140                                    int *off, int *nxt, u_short *offset);
 141 static int      port_match6 (u_short *portptr, int nports, u_short port,
 142                                 int range_flag);
 143 static int      tcp6flg_match (struct tcphdr *tcp6, struct ip6_fw *f);
 144 static int      icmp6type_match (struct icmp6_hdr *  icmp, struct ip6_fw * f);
 145 static void     ip6fw_report (struct ip6_fw *f, struct ip6_hdr *ip6,
 146                                 struct ifnet *rif, struct ifnet *oif, int off, int nxt);
 147
 148 static int      ip6_fw_chk (struct ip6_hdr **pip6,
 149                         struct ifnet *oif, u_int16_t *cookie, struct mbuf **m);
 150 static int      ip6_fw_ctl (int stage, struct mbuf **mm);
 151
 152 static char err_prefix[] = "ip6_fw_ctl:";
 153
 154 /*
 155  * Returns 1 if the port is matched by the vector, 0 otherwise
 156  */
 157 static
 158 __inline int
 159 port_match6(u_short *portptr, int nports, u_short port, int range_flag)
 160 {
 161         if (!nports)
 162                 return 1;
 163         if (range_flag) {
 164                 if (portptr[0] <= port && port <= portptr[1]) {
 165                         return 1;
 166                 }
 167                 nports -= 2;
 168                 portptr += 2;
 169         }
 170         while (nports-- > 0) {
 171                 if (*portptr++ == port) {
 172                         return 1;
 173                 }
 174         }
 175         return 0;
 176 }
 177
 178 static int
 179 tcp6flg_match(struct tcphdr *tcp6, struct ip6_fw *f)
 180 {
 181         u_char          flg_set, flg_clr;
 182
 183         /*
 184          * If an established connection is required, reject packets that
 185          * have only SYN of RST|ACK|SYN set.  Otherwise, fall through to
 186          * other flag requirements.
 187          */
 188         if ((f->fw_ipflg & IPV6_FW_IF_TCPEST) &&
 189             ((tcp6->th_flags & (IPV6_FW_TCPF_RST | IPV6_FW_TCPF_ACK |
 190             IPV6_FW_TCPF_SYN)) == IPV6_FW_TCPF_SYN))
 191                 return 0;
 192
 193         flg_set = tcp6->th_flags & f->fw_tcpf;
 194         flg_clr = tcp6->th_flags & f->fw_tcpnf;
 195
 196         if (flg_set != f->fw_tcpf)
 197                 return 0;
 198         if (flg_clr)
 199                 return 0;
 200
 201         return 1;
 202 }
 203
 204 static int
 205 icmp6type_match(struct icmp6_hdr *icmp6, struct ip6_fw *f)
 206 {
 207         int type;
 208
 209         if (!(f->fw_flg & IPV6_FW_F_ICMPBIT))
 210                 return(1);
 211
 212         type = icmp6->icmp6_type;
 213
 214         /* check for matching type in the bitmap */
 215         if (type < IPV6_FW_ICMPTYPES_DIM * sizeof(unsigned) * 8 &&
 216                 (f->fw_icmp6types[type / (sizeof(unsigned) * 8)] &
 217                 (1U << (type % (8 * sizeof(unsigned))))))
 218                 return(1);
 219
 220         return(0); /* no match */
 221 }
 222
 223 static int
 224 is_icmp6_query(struct ip6_hdr *ip6, int off)
 225 {
 226         const struct icmp6_hdr *icmp6;
 227         int icmp6_type;
 228
 229         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 230         icmp6_type = icmp6->icmp6_type;
 231
 232         if (icmp6_type == ICMP6_ECHO_REQUEST ||
 233             icmp6_type == ICMP6_MEMBERSHIP_QUERY ||
 234             icmp6_type == ICMP6_WRUREQUEST ||
 235             icmp6_type == ICMP6_FQDN_QUERY ||
 236             icmp6_type == ICMP6_NI_QUERY)
 237                 return(1);
 238
 239         return(0);
 240 }
 241
 242 static int
 243 ip6opts_match(struct ip6_hdr **pip6, struct ip6_fw *f, struct mbuf **m,
 244               int *off, int *nxt, u_short *offset)
 245 {
 246         int len;
 247         struct ip6_hdr *ip6 = *pip6;
 248         struct ip6_ext *ip6e;
 249         u_char  opts, nopts, nopts_sve;
 250
 251         opts = f->fw_ip6opt;
 252         nopts = nopts_sve = f->fw_ip6nopt;
 253
 254         *nxt = ip6->ip6_nxt;
 255         *off = sizeof(struct ip6_hdr);
 256         len = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr);
 257         while (*off < len) {
 258                 ip6e = (struct ip6_ext *)((caddr_t) ip6 + *off);
 259                 if ((*m)->m_len < *off + sizeof(*ip6e))
 260                         goto opts_check;        /* XXX */
 261
 262                 switch(*nxt) {
 263                 case IPPROTO_FRAGMENT:
 264                         if ((*m)->m_len >= *off + sizeof(struct ip6_frag)) {
 265                                 struct ip6_frag *ip6f;
 266
 267                                 ip6f = (struct ip6_frag *) ((caddr_t)ip6 + *off);
 268                                 *offset = ip6f->ip6f_offlg & IP6F_OFF_MASK;
 269                         }
 270                         opts &= ~IPV6_FW_IP6OPT_FRAG;
 271                         nopts &= ~IPV6_FW_IP6OPT_FRAG;
 272                         *off += sizeof(struct ip6_frag);
 273                         break;
 274                 case IPPROTO_AH:
 275                         opts &= ~IPV6_FW_IP6OPT_AH;
 276                         nopts &= ~IPV6_FW_IP6OPT_AH;
 277                         *off += (ip6e->ip6e_len + 2) << 2;
 278                         break;
 279                 default:
 280                         switch (*nxt) {
 281                         case IPPROTO_HOPOPTS:
 282                                 opts &= ~IPV6_FW_IP6OPT_HOPOPT;
 283                                 nopts &= ~IPV6_FW_IP6OPT_HOPOPT;
 284                                 break;
 285                         case IPPROTO_ROUTING:
 286                                 opts &= ~IPV6_FW_IP6OPT_ROUTE;
 287                                 nopts &= ~IPV6_FW_IP6OPT_ROUTE;
 288                                 break;
 289                         case IPPROTO_ESP:
 290                                 opts &= ~IPV6_FW_IP6OPT_ESP;
 291                                 nopts &= ~IPV6_FW_IP6OPT_ESP;
 292                                 goto opts_check;
 293                         case IPPROTO_NONE:
 294                                 opts &= ~IPV6_FW_IP6OPT_NONXT;
 295                                 nopts &= ~IPV6_FW_IP6OPT_NONXT;
 296                                 goto opts_check;
 297                         case IPPROTO_DSTOPTS:
 298                                 opts &= ~IPV6_FW_IP6OPT_OPTS;
 299                                 nopts &= ~IPV6_FW_IP6OPT_OPTS;
 300                                 break;
 301                         default:
 302                                 goto opts_check;
 303                         }
 304                         *off += (ip6e->ip6e_len + 1) << 3;
 305                         break;
 306                 }
 307                 *nxt = ip6e->ip6e_nxt;
 308
 309         }
 310  opts_check:
 311         if (f->fw_ip6opt == f->fw_ip6nopt)      /* XXX */
 312                 return 1;
 313
 314         if (opts == 0 && nopts == nopts_sve)
 315                 return 1;
 316         else
 317                 return 0;
 318 }
 319
 320 static
 321 __inline int
 322 iface_match(struct ifnet *ifp, union ip6_fw_if *ifu, int byname)
 323 {
 324         /* Check by name or by IP address */
 325         if (byname) {
 326                 /* Check name */
 327                 if (ifu->fu_via_if.glob) {
 328                         if (fnmatch(ifu->fu_via_if.name, ifp->if_xname, 0)
 329                             == FNM_NOMATCH)
 330                                 return(0);
 331                 } else {
 332                         if (strncmp(ifp->if_xname, ifu->fu_via_if.name,
 333                             IP6FW_IFNLEN) != 0)
 334                                 return(0);
 335                 }
 336                 return(1);
 337         } else if (!IN6_IS_ADDR_UNSPECIFIED(&ifu->fu_via_ip6)) {        /* Zero == wildcard */
 338                 struct ifaddr *ifa;
 339
 340                 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 341                         if (ifa->ifa_addr == NULL)
 342                                 continue;
 343                         if (ifa->ifa_addr->sa_family != AF_INET6)
 344                                 continue;
 345                         if (!IN6_ARE_ADDR_EQUAL(&ifu->fu_via_ip6,
 346                             &(((struct sockaddr_in6 *)
 347                             (ifa->ifa_addr))->sin6_addr)))
 348                                 continue;
 349                         return(1);
 350                 }
 351                 return(0);
 352         }
 353         return(1);
 354 }
 355
 356 static void
 357 ip6fw_report(struct ip6_fw *f, struct ip6_hdr *ip6,
 358         struct ifnet *rif, struct ifnet *oif, int off, int nxt)
 359 {
 360         static int counter;
 361         struct tcphdr *const tcp6 = (struct tcphdr *) ((caddr_t) ip6+ off);
 362         struct udphdr *const udp = (struct udphdr *) ((caddr_t) ip6+ off);
 363         struct icmp6_hdr *const icmp6 = (struct icmp6_hdr *) ((caddr_t) ip6+ off);
 364         int count;
 365         char *action;
 366         char action2[32], proto[102], name[18];
 367         int len;
 368
 369         count = f ? f->fw_pcnt : ++counter;
 370         if (fw6_verbose_limit != 0 && count > fw6_verbose_limit)
 371                 return;
 372
 373         /* Print command name */
 374         snprintf(SNPARGS(name, 0), "ip6fw: %d", f ? f->fw_number : -1);
 375
 376         action = action2;
 377         if (!f)
 378                 action = "Refuse";
 379         else {
 380                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 381                 case IPV6_FW_F_DENY:
 382                         action = "Deny";
 383                         break;
 384                 case IPV6_FW_F_REJECT:
 385                         if (f->fw_reject_code == IPV6_FW_REJECT_RST)
 386                                 action = "Reset";
 387                         else
 388                                 action = "Unreach";
 389                         break;
 390                 case IPV6_FW_F_ACCEPT:
 391                         action = "Accept";
 392                         break;
 393                 case IPV6_FW_F_COUNT:
 394                         action = "Count";
 395                         break;
 396                 case IPV6_FW_F_DIVERT:
 397                         snprintf(SNPARGS(action2, 0), "Divert %d",
 398                             f->fw_divert_port);
 399                         break;
 400                 case IPV6_FW_F_TEE:
 401                         snprintf(SNPARGS(action2, 0), "Tee %d",
 402                             f->fw_divert_port);
 403                         break;
 404                 case IPV6_FW_F_SKIPTO:
 405                         snprintf(SNPARGS(action2, 0), "SkipTo %d",
 406                             f->fw_skipto_rule);
 407                         break;
 408                 default:
 409                         action = "UNKNOWN";
 410                         break;
 411                 }
 412         }
 413
 414         switch (nxt) {
 415         case IPPROTO_TCP:
 416                 len = snprintf(SNPARGS(proto, 0), "TCP [%s]",
 417                     ip6_sprintf(&ip6->ip6_src));
 418                 if (off > 0)
 419                         len += snprintf(SNPARGS(proto, len), ":%d ",
 420                             ntohs(tcp6->th_sport));
 421                 else
 422                         len += snprintf(SNPARGS(proto, len), " ");
 423                 len += snprintf(SNPARGS(proto, len), "[%s]",
 424                     ip6_sprintf(&ip6->ip6_dst));
 425                 if (off > 0)
 426                         snprintf(SNPARGS(proto, len), ":%d",
 427                             ntohs(tcp6->th_dport));
 428                 break;
 429         case IPPROTO_UDP:
 430                 len = snprintf(SNPARGS(proto, 0), "UDP [%s]",
 431                     ip6_sprintf(&ip6->ip6_src));
 432                 if (off > 0)
 433                         len += snprintf(SNPARGS(proto, len), ":%d ",
 434                             ntohs(udp->uh_sport));
 435                 else
 436                     len += snprintf(SNPARGS(proto, len), " ");
 437                 len += snprintf(SNPARGS(proto, len), "[%s]",
 438                     ip6_sprintf(&ip6->ip6_dst));
 439                 if (off > 0)
 440                         snprintf(SNPARGS(proto, len), ":%d",
 441                             ntohs(udp->uh_dport));
 442                 break;
 443         case IPPROTO_ICMPV6:
 444                 if (off > 0)
 445                         len = snprintf(SNPARGS(proto, 0), "IPV6-ICMP:%u.%u ",
 446                             icmp6->icmp6_type, icmp6->icmp6_code);
 447                 else
 448                         len = snprintf(SNPARGS(proto, 0), "IPV6-ICMP ");
 449                 len += snprintf(SNPARGS(proto, len), "[%s]",
 450                     ip6_sprintf(&ip6->ip6_src));
 451                 snprintf(SNPARGS(proto, len), " [%s]",
 452                     ip6_sprintf(&ip6->ip6_dst));
 453                 break;
 454         default:
 455                 len = snprintf(SNPARGS(proto, 0), "P:%d [%s]", nxt,
 456                     ip6_sprintf(&ip6->ip6_src));
 457                 snprintf(SNPARGS(proto, len), " [%s]",
 458                     ip6_sprintf(&ip6->ip6_dst));
 459                 break;
 460         }
 461
 462         if (oif)
 463                 log(LOG_SECURITY | LOG_INFO, "%s %s %s out via %s\n",
 464                     name, action, proto, if_name(oif));
 465         else if (rif)
 466                 log(LOG_SECURITY | LOG_INFO, "%s %s %s in via %s\n",
 467                     name, action, proto, if_name(rif));
 468         else
 469                 log(LOG_SECURITY | LOG_INFO, "%s %s %s",
 470                     name, action, proto);
 471         if (fw6_verbose_limit != 0 && count == fw6_verbose_limit)
 472             log(LOG_SECURITY | LOG_INFO, "ip6fw: limit reached on entry %d\n",
 473                 f ? f->fw_number : -1);
 474 }
 475
 476 /*
 477  * Parameters:
 478  *
 479  *      ip      Pointer to packet header (struct ip6_hdr *)
 480  *      hlen    Packet header length
 481  *      oif     Outgoing interface, or NULL if packet is incoming
 482  * #ifndef IP6FW_DIVERT_RESTART
 483  *      *cookie Ignore all divert/tee rules to this port (if non-zero)
 484  * #else
 485  *      *cookie Skip up to the first rule past this rule number;
 486  * #endif
 487  *      *m      The packet; we set to NULL when/if we nuke it.
 488  *
 489  * Return value:
 490  *
 491  *      0       The packet is to be accepted and routed normally OR
 492  *              the packet was denied/rejected and has been dropped;
 493  *              in the latter case, *m is equal to NULL upon return.
 494  *      port    Divert the packet to port.
 495  */
 496
 497 static int
 498 ip6_fw_chk(struct ip6_hdr **pip6,
 499         struct ifnet *oif, u_int16_t *cookie, struct mbuf **m)
 500 {
 501         struct ip6_fw_chain *chain;
 502         struct ip6_fw *rule = NULL;
 503         struct ip6_hdr *ip6 = *pip6;
 504         struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
 505         u_short offset = 0;
 506         int off = sizeof(struct ip6_hdr), nxt = ip6->ip6_nxt;
 507         u_short src_port, dst_port;
 508 #ifdef  IP6FW_DIVERT_RESTART
 509         u_int16_t skipto = *cookie;
 510 #else
 511         u_int16_t ignport = ntohs(*cookie);
 512 #endif
 513
 514         *cookie = 0;
 515         /*
 516          * Go down the chain, looking for enlightment
 517          * #ifdef IP6FW_DIVERT_RESTART
 518          * If we've been asked to start at a given rule immediatly, do so.
 519          * #endif
 520          */
 521         chain = LIST_FIRST(&ip6_fw_chain);
 522 #ifdef IP6FW_DIVERT_RESTART
 523         if (skipto) {
 524                 if (skipto >= 65535)
 525                         goto dropit;
 526                 while (chain && (chain->rule->fw_number <= skipto)) {
 527                         chain = LIST_NEXT(chain, chain);
 528                 }
 529                 if (! chain) goto dropit;
 530         }
 531 #endif /* IP6FW_DIVERT_RESTART */
 532         for (; chain; chain = LIST_NEXT(chain, chain)) {
 533                 struct ip6_fw *const f = chain->rule;
 534
 535                 if (oif) {
 536                         /* Check direction outbound */
 537                         if (!(f->fw_flg & IPV6_FW_F_OUT))
 538                                 continue;
 539                 } else {
 540                         /* Check direction inbound */
 541                         if (!(f->fw_flg & IPV6_FW_F_IN))
 542                                 continue;
 543                 }
 544
 545 #define IN6_ARE_ADDR_MASKEQUAL(x,y,z) (\
 546         (((x)->s6_addr32[0] & (y)->s6_addr32[0]) == (z)->s6_addr32[0]) && \
 547         (((x)->s6_addr32[1] & (y)->s6_addr32[1]) == (z)->s6_addr32[1]) && \
 548         (((x)->s6_addr32[2] & (y)->s6_addr32[2]) == (z)->s6_addr32[2]) && \
 549         (((x)->s6_addr32[3] & (y)->s6_addr32[3]) == (z)->s6_addr32[3]))
 550
 551                 /* If src-addr doesn't match, not this rule. */
 552                 if (((f->fw_flg & IPV6_FW_F_INVSRC) != 0) ^
 553                         (!IN6_ARE_ADDR_MASKEQUAL(&ip6->ip6_src,&f->fw_smsk,&f->fw_src)))
 554                         continue;
 555
 556                 /* If dest-addr doesn't match, not this rule. */
 557                 if (((f->fw_flg & IPV6_FW_F_INVDST) != 0) ^
 558                         (!IN6_ARE_ADDR_MASKEQUAL(&ip6->ip6_dst,&f->fw_dmsk,&f->fw_dst)))
 559                         continue;
 560
 561 #undef IN6_ARE_ADDR_MASKEQUAL
 562                 /* Interface check */
 563                 if ((f->fw_flg & IF6_FW_F_VIAHACK) == IF6_FW_F_VIAHACK) {
 564                         struct ifnet *const iface = oif ? oif : rif;
 565
 566                         /* Backwards compatibility hack for "via" */
 567                         if (!iface || !iface_match(iface,
 568                             &f->fw_in_if, f->fw_flg & IPV6_FW_F_OIFNAME))
 569                                 continue;
 570                 } else {
 571                         /* Check receive interface */
 572                         if ((f->fw_flg & IPV6_FW_F_IIFACE)
 573                             && (!rif || !iface_match(rif,
 574                               &f->fw_in_if, f->fw_flg & IPV6_FW_F_IIFNAME)))
 575                                 continue;
 576                         /* Check outgoing interface */
 577                         if ((f->fw_flg & IPV6_FW_F_OIFACE)
 578                             && (!oif || !iface_match(oif,
 579                               &f->fw_out_if, f->fw_flg & IPV6_FW_F_OIFNAME)))
 580                                 continue;
 581                 }
 582
 583                 /* Check IP options */
 584                 if (!ip6opts_match(&ip6, f, m, &off, &nxt, &offset))
 585                         continue;
 586
 587                 /* Fragments */
 588                 if ((f->fw_flg & IPV6_FW_F_FRAG) && !offset)
 589                         continue;
 590
 591                 /* Check protocol; if wildcard, match */
 592                 if (f->fw_prot == IPPROTO_IPV6)
 593                         goto got_match;
 594
 595                 /* If different, don't match */
 596                 if (nxt != f->fw_prot)
 597                         continue;
 598
 599 #define PULLUP_TO(len)  do {                                            \
 600                             if ((*m)->m_len < (len)                     \
 601                                 && (*m = m_pullup(*m, (len))) == 0) {   \
 602                                     goto dropit;                        \
 603                             }                                           \
 604                             *pip6 = ip6 = mtod(*m, struct ip6_hdr *);   \
 605                         } while (0)
 606
 607                 /* Protocol specific checks */
 608                 switch (nxt) {
 609                 case IPPROTO_TCP:
 610                     {
 611                         struct tcphdr *tcp6;
 612
 613                         if (offset == 1) {      /* cf. RFC 1858 */
 614                                 PULLUP_TO(off + 4); /* XXX ? */
 615                                 goto bogusfrag;
 616                         }
 617                         if (offset != 0) {
 618                                 /*
 619                                  * TCP flags and ports aren't available in this
 620                                  * packet -- if this rule specified either one,
 621                                  * we consider the rule a non-match.
 622                                  */
 623                                 if (f->fw_nports != 0 ||
 624                                     f->fw_tcpf != f->fw_tcpnf)
 625                                         continue;
 626
 627                                 break;
 628                         }
 629                         PULLUP_TO(off + 14);
 630                         tcp6 = (struct tcphdr *) ((caddr_t)ip6 + off);
 631                         if (((f->fw_tcpf != f->fw_tcpnf) ||
 632                            (f->fw_ipflg & IPV6_FW_IF_TCPEST))  &&
 633                            !tcp6flg_match(tcp6, f))
 634                                 continue;
 635                         src_port = ntohs(tcp6->th_sport);
 636                         dst_port = ntohs(tcp6->th_dport);
 637                         goto check_ports;
 638                     }
 639
 640                 case IPPROTO_UDP:
 641                     {
 642                         struct udphdr *udp;
 643
 644                         if (offset != 0) {
 645                                 /*
 646                                  * Port specification is unavailable -- if this
 647                                  * rule specifies a port, we consider the rule
 648                                  * a non-match.
 649                                  */
 650                                 if (f->fw_nports != 0)
 651                                         continue;
 652
 653                                 break;
 654                         }
 655                         PULLUP_TO(off + 4);
 656                         udp = (struct udphdr *) ((caddr_t)ip6 + off);
 657                         src_port = ntohs(udp->uh_sport);
 658                         dst_port = ntohs(udp->uh_dport);
 659 check_ports:
 660                         if (!port_match6(&f->fw_pts[0],
 661                             IPV6_FW_GETNSRCP(f), src_port,
 662                             f->fw_flg & IPV6_FW_F_SRNG))
 663                                 continue;
 664                         if (!port_match6(&f->fw_pts[IPV6_FW_GETNSRCP(f)],
 665                             IPV6_FW_GETNDSTP(f), dst_port,
 666                             f->fw_flg & IPV6_FW_F_DRNG))
 667                                 continue;
 668                         break;
 669                     }
 670
 671                 case IPPROTO_ICMPV6:
 672                     {
 673                         struct icmp6_hdr *icmp;
 674
 675                         if (offset != 0)        /* Type isn't valid */
 676                                 break;
 677                         PULLUP_TO(off + 2);
 678                         icmp = (struct icmp6_hdr *) ((caddr_t)ip6 + off);
 679                         if (!icmp6type_match(icmp, f))
 680                                 continue;
 681                         break;
 682                     }
 683 #undef PULLUP_TO
 684
 685 bogusfrag:
 686                         if (fw6_verbose)
 687                                 ip6fw_report(NULL, ip6, rif, oif, off, nxt);
 688                         goto dropit;
 689                 }
 690
 691 got_match:
 692 #ifndef IP6FW_DIVERT_RESTART
 693                 /* Ignore divert/tee rule if socket port is "ignport" */
 694                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 695                 case IPV6_FW_F_DIVERT:
 696                 case IPV6_FW_F_TEE:
 697                         if (f->fw_divert_port == ignport)
 698                                 continue;       /* ignore this rule */
 699                         break;
 700                 }
 701
 702 #endif /* IP6FW_DIVERT_RESTART */
 703                 /* Update statistics */
 704                 f->fw_pcnt += 1;
 705                 f->fw_bcnt += ntohs(ip6->ip6_plen);
 706                 f->timestamp = time_second;
 707
 708                 /* Log to console if desired */
 709                 if ((f->fw_flg & IPV6_FW_F_PRN) && fw6_verbose)
 710                         ip6fw_report(f, ip6, rif, oif, off, nxt);
 711
 712                 /* Take appropriate action */
 713                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 714                 case IPV6_FW_F_ACCEPT:
 715                         return(0);
 716                 case IPV6_FW_F_COUNT:
 717                         continue;
 718                 case IPV6_FW_F_DIVERT:
 719 #ifdef IP6FW_DIVERT_RESTART
 720                         *cookie = f->fw_number;
 721 #else
 722                         *cookie = htons(f->fw_divert_port);
 723 #endif /* IP6FW_DIVERT_RESTART */
 724                         return(f->fw_divert_port);
 725                 case IPV6_FW_F_TEE:
 726                         /*
 727                          * XXX someday tee packet here, but beware that you
 728                          * can't use m_copym() or m_copypacket() because
 729                          * the divert input routine modifies the mbuf
 730                          * (and these routines only increment reference
 731                          * counts in the case of mbuf clusters), so need
 732                          * to write custom routine.
 733                          */
 734                         continue;
 735                 case IPV6_FW_F_SKIPTO:
 736 #ifdef DIAGNOSTIC
 737                         while (chain->chain.le_next
 738                             && chain->chain.le_next->rule->fw_number
 739                                 < f->fw_skipto_rule)
 740 #else
 741                         while (chain->chain.le_next->rule->fw_number
 742                             < f->fw_skipto_rule)
 743 #endif
 744                                 chain = chain->chain.le_next;
 745                         continue;
 746                 }
 747
 748                 /* Deny/reject this packet using this rule */
 749                 rule = f;
 750                 break;
 751         }
 752
 753 #ifdef DIAGNOSTIC
 754         /* Rule 65535 should always be there and should always match */
 755         if (!chain)
 756                 panic("ip6_fw: chain");
 757 #endif
 758
 759         /*
 760          * At this point, we're going to drop the packet.
 761          * Send a reject notice if all of the following are true:
 762          *
 763          * - The packet matched a reject rule
 764          * - The packet is not an ICMP packet, or is an ICMP query packet
 765          * - The packet is not a multicast or broadcast packet
 766          */
 767         if ((rule->fw_flg & IPV6_FW_F_COMMAND) == IPV6_FW_F_REJECT
 768             && (nxt != IPPROTO_ICMPV6 || is_icmp6_query(ip6, off))
 769             && !((*m)->m_flags & (M_BCAST|M_MCAST))
 770             && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 771                 switch (rule->fw_reject_code) {
 772                 case IPV6_FW_REJECT_RST:
 773                   {
 774                         struct tcphdr *const tcp =
 775                                 (struct tcphdr *) ((caddr_t)ip6 + off);
 776                         struct {
 777                                 struct ip6_hdr ip6;
 778                                 struct tcphdr th;
 779                         } ti;
 780                         tcp_seq ack, seq;
 781                         int flags;
 782
 783                         if (offset != 0 || (tcp->th_flags & TH_RST))
 784                                 break;
 785
 786                         ti.ip6 = *ip6;
 787                         ti.th = *tcp;
 788                         ti.th.th_seq = ntohl(ti.th.th_seq);
 789                         ti.th.th_ack = ntohl(ti.th.th_ack);
 790                         ti.ip6.ip6_nxt = IPPROTO_TCP;
 791                         if (ti.th.th_flags & TH_ACK) {
 792                                 ack = 0;
 793                                 seq = ti.th.th_ack;
 794                                 flags = TH_RST;
 795                         } else {
 796                                 ack = ti.th.th_seq;
 797                                 if (((*m)->m_flags & M_PKTHDR) != 0) {
 798                                         ack += (*m)->m_pkthdr.len - off
 799                                                 - (ti.th.th_off << 2);
 800                                 } else if (ip6->ip6_plen) {
 801                                         ack += ntohs(ip6->ip6_plen) + sizeof(*ip6)
 802                                                 - off - (ti.th.th_off << 2);
 803                                 } else {
 804                                         m_freem(*m);
 805                                         *m = 0;
 806                                         break;
 807                                 }
 808                                 seq = 0;
 809                                 flags = TH_RST|TH_ACK;
 810                         }
 811                         bcopy(&ti, ip6, sizeof(ti));
 812                         tcp_respond(NULL, ip6, (struct tcphdr *)(ip6 + 1),
 813                                 *m, ack, seq, flags);
 814                         *m = NULL;
 815                         break;
 816                   }
 817                 default:        /* Send an ICMP unreachable using code */
 818                         if (oif)
 819                                 (*m)->m_pkthdr.rcvif = oif;
 820                         icmp6_error(*m, ICMP6_DST_UNREACH,
 821                             rule->fw_reject_code, 0);
 822                         *m = NULL;
 823                         break;
 824                 }
 825         }
 826
 827 dropit:
 828         /*
 829          * Finally, drop the packet.
 830          */
 831         if (*m) {
 832                 m_freem(*m);
 833                 *m = NULL;
 834         }
 835         return(0);
 836 }
 837
 838 static int
 839 add_entry6(struct ip6_fw_head *chainptr, struct ip6_fw *frwl)
 840 {
 841         struct ip6_fw *ftmp = 0;
 842         struct ip6_fw_chain *fwc = 0, *fcp, *fcpl = 0;
 843         u_short nbr = 0;
 844         int s;
 845
 846         fwc = malloc(sizeof *fwc, M_IP6FW, M_INTWAIT);
 847         ftmp = malloc(sizeof *ftmp, M_IP6FW, M_INTWAIT);
 848
 849         bcopy(frwl, ftmp, sizeof(struct ip6_fw));
 850         ftmp->fw_in_if.fu_via_if.name[IP6FW_IFNLEN - 1] = '\0';
 851         ftmp->fw_pcnt = 0L;
 852         ftmp->fw_bcnt = 0L;
 853         fwc->rule = ftmp;
 854
 855         s = splnet();
 856
 857         if (!chainptr->lh_first) {
 858                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 859                 splx(s);
 860                 return(0);
 861         } else if (ftmp->fw_number == (u_short)-1) {
 862                 if (fwc)  free(fwc, M_IP6FW);
 863                 if (ftmp) free(ftmp, M_IP6FW);
 864                 splx(s);
 865                 dprintf(("%s bad rule number\n", err_prefix));
 866                 return (EINVAL);
 867         }
 868
 869         /* If entry number is 0, find highest numbered rule and add 100 */
 870         if (ftmp->fw_number == 0) {
 871                 for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 872                         if (fcp->rule->fw_number != (u_short)-1)
 873                                 nbr = fcp->rule->fw_number;
 874                         else
 875                                 break;
 876                 }
 877                 if (nbr < (u_short)-1 - 100)
 878                         nbr += 100;
 879                 ftmp->fw_number = nbr;
 880         }
 881
 882         /* Got a valid number; now insert it, keeping the list ordered */
 883         for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 884                 if (fcp->rule->fw_number > ftmp->fw_number) {
 885                         if (fcpl) {
 886                                 LIST_INSERT_AFTER(fcpl, fwc, chain);
 887                         } else {
 888                                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 889                         }
 890                         break;
 891                 } else {
 892                         fcpl = fcp;
 893                 }
 894         }
 895
 896         splx(s);
 897         return (0);
 898 }
 899
 900 static int
 901 del_entry6(struct ip6_fw_head *chainptr, u_short number)
 902 {
 903         struct ip6_fw_chain *fcp;
 904         int s;
 905
 906         s = splnet();
 907
 908         fcp = chainptr->lh_first;
 909         if (number != (u_short)-1) {
 910                 for (; fcp; fcp = fcp->chain.le_next) {
 911                         if (fcp->rule->fw_number == number) {
 912                                 LIST_REMOVE(fcp, chain);
 913                                 splx(s);
 914                                 free(fcp->rule, M_IP6FW);
 915                                 free(fcp, M_IP6FW);
 916                                 return 0;
 917                         }
 918                 }
 919         }
 920
 921         splx(s);
 922         return (EINVAL);
 923 }
 924
 925 static int
 926 zero_entry6(struct mbuf *m)
 927 {
 928         struct ip6_fw *frwl;
 929         struct ip6_fw_chain *fcp;
 930         int s;
 931
 932         if (m && m->m_len != 0) {
 933                 if (m->m_len != sizeof(struct ip6_fw))
 934                         return(EINVAL);
 935                 frwl = mtod(m, struct ip6_fw *);
 936         }
 937         else
 938                 frwl = NULL;
 939
 940         /*
 941          *      It's possible to insert multiple chain entries with the
 942          *      same number, so we don't stop after finding the first
 943          *      match if zeroing a specific entry.
 944          */
 945         s = splnet();
 946         for (fcp = ip6_fw_chain.lh_first; fcp; fcp = fcp->chain.le_next)
 947                 if (!frwl || frwl->fw_number == fcp->rule->fw_number) {
 948                         fcp->rule->fw_bcnt = fcp->rule->fw_pcnt = 0;
 949                         fcp->rule->timestamp = 0;
 950                 }
 951         splx(s);
 952
 953         if (fw6_verbose) {
 954                 if (frwl)
 955                         log(LOG_SECURITY | LOG_NOTICE,
 956                             "ip6fw: Entry %d cleared.\n", frwl->fw_number);
 957                 else
 958                         log(LOG_SECURITY | LOG_NOTICE,
 959                             "ip6fw: Accounting cleared.\n");
 960         }
 961
 962         return(0);
 963 }
 964
 965 static struct ip6_fw *
 966 check_ip6fw_mbuf(struct mbuf *m)
 967 {
 968         /* Check length */
 969         if (m->m_len != sizeof(struct ip6_fw)) {
 970                 dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
 971                     sizeof(struct ip6_fw)));
 972                 return (NULL);
 973         }
 974         return(check_ip6fw_struct(mtod(m, struct ip6_fw *)));
 975 }
 976
 977 static struct ip6_fw *
 978 check_ip6fw_struct(struct ip6_fw *frwl)
 979 {
 980         /* Check for invalid flag bits */
 981         if ((frwl->fw_flg & ~IPV6_FW_F_MASK) != 0) {
 982                 dprintf(("%s undefined flag bits set (flags=%x)\n",
 983                     err_prefix, frwl->fw_flg));
 984                 return (NULL);
 985         }
 986         /* Must apply to incoming or outgoing (or both) */
 987         if (!(frwl->fw_flg & (IPV6_FW_F_IN | IPV6_FW_F_OUT))) {
 988                 dprintf(("%s neither in nor out\n", err_prefix));
 989                 return (NULL);
 990         }
 991         /* Empty interface name is no good */
 992         if (((frwl->fw_flg & IPV6_FW_F_IIFNAME)
 993               && !*frwl->fw_in_if.fu_via_if.name)
 994             || ((frwl->fw_flg & IPV6_FW_F_OIFNAME)
 995               && !*frwl->fw_out_if.fu_via_if.name)) {
 996                 dprintf(("%s empty interface name\n", err_prefix));
 997                 return (NULL);
 998         }
 999         /* Sanity check interface matching */
1000         if ((frwl->fw_flg & IF6_FW_F_VIAHACK) == IF6_FW_F_VIAHACK) {
1001                 ;               /* allow "via" backwards compatibility */
1002         } else if ((frwl->fw_flg & IPV6_FW_F_IN)
1003             && (frwl->fw_flg & IPV6_FW_F_OIFACE)) {
1004                 dprintf(("%s outgoing interface check on incoming\n",
1005                     err_prefix));
1006                 return (NULL);
1007         }
1008         /* Sanity check port ranges */
1009         if ((frwl->fw_flg & IPV6_FW_F_SRNG) && IPV6_FW_GETNSRCP(frwl) < 2) {
1010                 dprintf(("%s src range set but n_src_p=%d\n",
1011                     err_prefix, IPV6_FW_GETNSRCP(frwl)));
1012                 return (NULL);
1013         }
1014         if ((frwl->fw_flg & IPV6_FW_F_DRNG) && IPV6_FW_GETNDSTP(frwl) < 2) {
1015                 dprintf(("%s dst range set but n_dst_p=%d\n",
1016                     err_prefix, IPV6_FW_GETNDSTP(frwl)));
1017                 return (NULL);
1018         }
1019         if (IPV6_FW_GETNSRCP(frwl) + IPV6_FW_GETNDSTP(frwl) > IPV6_FW_MAX_PORTS) {
1020                 dprintf(("%s too many ports (%d+%d)\n",
1021                     err_prefix, IPV6_FW_GETNSRCP(frwl), IPV6_FW_GETNDSTP(frwl)));
1022                 return (NULL);
1023         }
1024         /*
1025          *      Protocols other than TCP/UDP don't use port range
1026          */
1027         if ((frwl->fw_prot != IPPROTO_TCP) &&
1028             (frwl->fw_prot != IPPROTO_UDP) &&
1029             (IPV6_FW_GETNSRCP(frwl) || IPV6_FW_GETNDSTP(frwl))) {
1030                 dprintf(("%s port(s) specified for non TCP/UDP rule\n",
1031                     err_prefix));
1032                 return(NULL);
1033         }
1034
1035         /*
1036          *      Rather than modify the entry to make such entries work,
1037          *      we reject this rule and require user level utilities
1038          *      to enforce whatever policy they deem appropriate.
1039          */
1040         if ((frwl->fw_src.s6_addr32[0] & (~frwl->fw_smsk.s6_addr32[0])) ||
1041                 (frwl->fw_src.s6_addr32[1] & (~frwl->fw_smsk.s6_addr32[1])) ||
1042                 (frwl->fw_src.s6_addr32[2] & (~frwl->fw_smsk.s6_addr32[2])) ||
1043                 (frwl->fw_src.s6_addr32[3] & (~frwl->fw_smsk.s6_addr32[3])) ||
1044                 (frwl->fw_dst.s6_addr32[0] & (~frwl->fw_dmsk.s6_addr32[0])) ||
1045                 (frwl->fw_dst.s6_addr32[1] & (~frwl->fw_dmsk.s6_addr32[1])) ||
1046                 (frwl->fw_dst.s6_addr32[2] & (~frwl->fw_dmsk.s6_addr32[2])) ||
1047                 (frwl->fw_dst.s6_addr32[3] & (~frwl->fw_dmsk.s6_addr32[3]))) {
1048                 dprintf(("%s rule never matches\n", err_prefix));
1049                 return(NULL);
1050         }
1051
1052         if ((frwl->fw_flg & IPV6_FW_F_FRAG) &&
1053                 (frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
1054                 if (frwl->fw_nports) {
1055                         dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
1056                         return(NULL);
1057                 }
1058                 if (frwl->fw_prot == IPPROTO_TCP &&
1059                         frwl->fw_tcpf != frwl->fw_tcpnf) {
1060                         dprintf(("%s cannot mix 'frag' with TCP flags\n", err_prefix));
1061                         return(NULL);
1062                 }
1063         }
1064
1065         /* Check command specific stuff */
1066         switch (frwl->fw_flg & IPV6_FW_F_COMMAND)
1067         {
1068         case IPV6_FW_F_REJECT:
1069                 if (frwl->fw_reject_code >= 0x100
1070                     && !(frwl->fw_prot == IPPROTO_TCP
1071                       && frwl->fw_reject_code == IPV6_FW_REJECT_RST)) {
1072                         dprintf(("%s unknown reject code\n", err_prefix));
1073                         return(NULL);
1074                 }
1075                 break;
1076         case IPV6_FW_F_DIVERT:          /* Diverting to port zero is invalid */
1077         case IPV6_FW_F_TEE:
1078                 if (frwl->fw_divert_port == 0) {
1079                         dprintf(("%s can't divert to port 0\n", err_prefix));
1080                         return (NULL);
1081                 }
1082                 break;
1083         case IPV6_FW_F_DENY:
1084         case IPV6_FW_F_ACCEPT:
1085         case IPV6_FW_F_COUNT:
1086         case IPV6_FW_F_SKIPTO:
1087                 break;
1088         default:
1089                 dprintf(("%s invalid command\n", err_prefix));
1090                 return(NULL);
1091         }
1092
1093         return frwl;
1094 }
1095
1096 static int
1097 ip6_fw_ctl(int stage, struct mbuf **mm)
1098 {
1099         int error;
1100         struct mbuf *m;
1101
1102         if (stage == IPV6_FW_GET) {
1103                 struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1104                 *mm = m = m_get(MB_WAIT, MT_DATA); /* XXX */
1105                 if (!m)
1106                         return(ENOBUFS);
1107                 if (sizeof *(fcp->rule) > MLEN) {
1108                         MCLGET(m, MB_WAIT);
1109                         if ((m->m_flags & M_EXT) == 0) {
1110                                 m_free(m);
1111                                 return(ENOBUFS);
1112                         }
1113                 }
1114                 for (; fcp; fcp = fcp->chain.le_next) {
1115                         bcopy(fcp->rule, m->m_data, sizeof *(fcp->rule));
1116                         m->m_len = sizeof *(fcp->rule);
1117                         m->m_next = m_get(MB_WAIT, MT_DATA); /* XXX */
1118                         if (!m->m_next) {
1119                                 m_freem(*mm);
1120                                 return(ENOBUFS);
1121                         }
1122                         m = m->m_next;
1123                         if (sizeof *(fcp->rule) > MLEN) {
1124                                 MCLGET(m, MB_WAIT);
1125                                 if ((m->m_flags & M_EXT) == 0) {
1126                                         m_freem(*mm);
1127                                         return(ENOBUFS);
1128                                 }
1129                         }
1130                         m->m_len = 0;
1131                 }
1132                 return (0);
1133         }
1134         m = *mm;
1135         /* only allow get calls if secure mode > 2 */
1136         if (securelevel > 2) {
1137                 if (m) {
1138                         (void)m_freem(m);
1139                         *mm = 0;
1140                 }
1141                 return(EPERM);
1142         }
1143         if (stage == IPV6_FW_FLUSH) {
1144                 while (ip6_fw_chain.lh_first != NULL &&
1145                     ip6_fw_chain.lh_first->rule->fw_number != (u_short)-1) {
1146                         struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1147                         int s = splnet();
1148                         LIST_REMOVE(ip6_fw_chain.lh_first, chain);
1149                         splx(s);
1150                         free(fcp->rule, M_IP6FW);
1151                         free(fcp, M_IP6FW);
1152                 }
1153                 if (m) {
1154                         (void)m_freem(m);
1155                         *mm = 0;
1156                 }
1157                 return (0);
1158         }
1159         if (stage == IPV6_FW_ZERO) {
1160                 error = zero_entry6(m);
1161                 if (m) {
1162                         (void)m_freem(m);
1163                         *mm = 0;
1164                 }
1165                 return (error);
1166         }
1167         if (m == NULL) {
1168                 printf("%s NULL mbuf ptr\n", err_prefix);
1169                 return (EINVAL);
1170         }
1171
1172         if (stage == IPV6_FW_ADD) {
1173                 struct ip6_fw *frwl = check_ip6fw_mbuf(m);
1174
1175                 if (!frwl)
1176                         error = EINVAL;
1177                 else
1178                         error = add_entry6(&ip6_fw_chain, frwl);
1179                 if (m) {
1180                         (void)m_freem(m);
1181                         *mm = 0;
1182                 }
1183                 return error;
1184         }
1185         if (stage == IPV6_FW_DEL) {
1186                 if (m->m_len != sizeof(struct ip6_fw)) {
1187                         dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
1188                             sizeof(struct ip6_fw)));
1189                         error = EINVAL;
1190                 } else if (mtod(m, struct ip6_fw *)->fw_number == (u_short)-1) {
1191                         dprintf(("%s can't delete rule 65535\n", err_prefix));
1192                         error = EINVAL;
1193                 } else
1194                         error = del_entry6(&ip6_fw_chain,
1195                             mtod(m, struct ip6_fw *)->fw_number);
1196                 if (m) {
1197                         (void)m_freem(m);
1198                         *mm = 0;
1199                 }
1200                 return error;
1201         }
1202
1203         dprintf(("%s unknown request %d\n", err_prefix, stage));
1204         if (m) {
1205                 (void)m_freem(m);
1206                 *mm = 0;
1207         }
1208         return (EINVAL);
1209 }
1210
1211 void
1212 ip6_fw_init(void)
1213 {
1214         struct ip6_fw default_rule;
1215
1216         ip6_fw_chk_ptr = ip6_fw_chk;
1217         ip6_fw_ctl_ptr = ip6_fw_ctl;
1218         LIST_INIT(&ip6_fw_chain);
1219
1220         bzero(&default_rule, sizeof default_rule);
1221         default_rule.fw_prot = IPPROTO_IPV6;
1222         default_rule.fw_number = (u_short)-1;
1223 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1224         default_rule.fw_flg |= IPV6_FW_F_ACCEPT;
1225 #else
1226         default_rule.fw_flg |= IPV6_FW_F_DENY;
1227 #endif
1228         default_rule.fw_flg |= IPV6_FW_F_IN | IPV6_FW_F_OUT;
1229         if (check_ip6fw_struct(&default_rule) == NULL ||
1230                 add_entry6(&ip6_fw_chain, &default_rule))
1231                 panic(__FUNCTION__);
1232
1233         printf("IPv6 packet filtering initialized, ");
1234 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1235         printf("default to accept, ");
1236 #endif
1237 #ifndef IPV6FIREWALL_VERBOSE
1238         printf("logging disabled\n");
1239 #else
1240         if (fw6_verbose_limit == 0)
1241                 printf("unlimited logging\n");
1242         else
1243                 printf("logging limited to %d packets/entry\n",
1244                     fw6_verbose_limit);
1245 #endif
1246 }
1247
1248 static ip6_fw_chk_t *old_chk_ptr;
1249 static ip6_fw_ctl_t *old_ctl_ptr;
1250
1251 static int
1252 ip6fw_modevent(module_t mod, int type, void *unused)
1253 {
1254         int s;
1255
1256         switch (type) {
1257         case MOD_LOAD:
1258                 s = splnet();
1259
1260                 old_chk_ptr = ip6_fw_chk_ptr;
1261                 old_ctl_ptr = ip6_fw_ctl_ptr;
1262
1263                 ip6_fw_init();
1264                 splx(s);
1265                 return 0;
1266         case MOD_UNLOAD:
1267                 s = splnet();
1268                 ip6_fw_chk_ptr =  old_chk_ptr;
1269                 ip6_fw_ctl_ptr =  old_ctl_ptr;
1270                 while (LIST_FIRST(&ip6_fw_chain) != NULL) {
1271                         struct ip6_fw_chain *fcp = LIST_FIRST(&ip6_fw_chain);
1272                         LIST_REMOVE(LIST_FIRST(&ip6_fw_chain), chain);
1273                         free(fcp->rule, M_IP6FW);
1274                         free(fcp, M_IP6FW);
1275                 }
1276
1277                 splx(s);
1278                 printf("IPv6 firewall unloaded\n");
1279                 return 0;
1280         default:
1281                 break;
1282         }
1283         return 0;
1284 }
1285
1286 static moduledata_t ip6fwmod = {
1287         "ip6fw",
1288         ip6fw_modevent,
1289         0
1290 };
1291 DECLARE_MODULE(ip6fw, ip6fwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);