sys/net/ip6fw/ip6_fw.c

   1 /*      $FreeBSD: src/sys/netinet6/ip6_fw.c,v 1.2.2.9 2002/04/28 05:40:27 suz Exp $     */
   2 /*      $DragonFly: src/sys/net/ip6fw/ip6_fw.c,v 1.8 2004/06/02 14:42:58 eirikn 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                                 break;
 293                         case IPPROTO_NONE:
 294                                 opts &= ~IPV6_FW_IP6OPT_NONXT;
 295                                 nopts &= ~IPV6_FW_IP6OPT_NONXT;
 296                                 goto opts_check;
 297                                 break;
 298                         case IPPROTO_DSTOPTS:
 299                                 opts &= ~IPV6_FW_IP6OPT_OPTS;
 300                                 nopts &= ~IPV6_FW_IP6OPT_OPTS;
 301                                 break;
 302                         default:
 303                                 goto opts_check;
 304                                 break;
 305                         }
 306                         *off += (ip6e->ip6e_len + 1) << 3;
 307                         break;
 308                 }
 309                 *nxt = ip6e->ip6e_nxt;
 310
 311         }
 312  opts_check:
 313         if (f->fw_ip6opt == f->fw_ip6nopt)      /* XXX */
 314                 return 1;
 315
 316         if (opts == 0 && nopts == nopts_sve)
 317                 return 1;
 318         else
 319                 return 0;
 320 }
 321
 322 static
 323 __inline int
 324 iface_match(struct ifnet *ifp, union ip6_fw_if *ifu, int byname)
 325 {
 326         /* Check by name or by IP address */
 327         if (byname) {
 328                 /* Check name */
 329                 if (ifu->fu_via_if.glob) {
 330                         if (fnmatch(ifu->fu_via_if.name, ifp->if_xname, 0)
 331                             == FNM_NOMATCH)
 332                                 return(0);
 333                 } else {
 334                         if (strncmp(ifp->if_xname, ifu->fu_via_if.name,
 335                             IP6FW_IFNLEN) != 0)
 336                                 return(0);
 337                 }
 338                 return(1);
 339         } else if (!IN6_IS_ADDR_UNSPECIFIED(&ifu->fu_via_ip6)) {        /* Zero == wildcard */
 340                 struct ifaddr *ia;
 341
 342                 for (ia = ifp->if_addrlist.tqh_first; ia; ia = ia->ifa_list.tqe_next)
 343                 {
 344
 345                         if (ia->ifa_addr == NULL)
 346                                 continue;
 347                         if (ia->ifa_addr->sa_family != AF_INET6)
 348                                 continue;
 349                         if (!IN6_ARE_ADDR_EQUAL(&ifu->fu_via_ip6,
 350                             &(((struct sockaddr_in6 *)
 351                             (ia->ifa_addr))->sin6_addr)))
 352                                 continue;
 353                         return(1);
 354                 }
 355                 return(0);
 356         }
 357         return(1);
 358 }
 359
 360 static void
 361 ip6fw_report(struct ip6_fw *f, struct ip6_hdr *ip6,
 362         struct ifnet *rif, struct ifnet *oif, int off, int nxt)
 363 {
 364         static int counter;
 365         struct tcphdr *const tcp6 = (struct tcphdr *) ((caddr_t) ip6+ off);
 366         struct udphdr *const udp = (struct udphdr *) ((caddr_t) ip6+ off);
 367         struct icmp6_hdr *const icmp6 = (struct icmp6_hdr *) ((caddr_t) ip6+ off);
 368         int count;
 369         char *action;
 370         char action2[32], proto[102], name[18];
 371         int len;
 372
 373         count = f ? f->fw_pcnt : ++counter;
 374         if (fw6_verbose_limit != 0 && count > fw6_verbose_limit)
 375                 return;
 376
 377         /* Print command name */
 378         snprintf(SNPARGS(name, 0), "ip6fw: %d", f ? f->fw_number : -1);
 379
 380         action = action2;
 381         if (!f)
 382                 action = "Refuse";
 383         else {
 384                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 385                 case IPV6_FW_F_DENY:
 386                         action = "Deny";
 387                         break;
 388                 case IPV6_FW_F_REJECT:
 389                         if (f->fw_reject_code == IPV6_FW_REJECT_RST)
 390                                 action = "Reset";
 391                         else
 392                                 action = "Unreach";
 393                         break;
 394                 case IPV6_FW_F_ACCEPT:
 395                         action = "Accept";
 396                         break;
 397                 case IPV6_FW_F_COUNT:
 398                         action = "Count";
 399                         break;
 400                 case IPV6_FW_F_DIVERT:
 401                         snprintf(SNPARGS(action2, 0), "Divert %d",
 402                             f->fw_divert_port);
 403                         break;
 404                 case IPV6_FW_F_TEE:
 405                         snprintf(SNPARGS(action2, 0), "Tee %d",
 406                             f->fw_divert_port);
 407                         break;
 408                 case IPV6_FW_F_SKIPTO:
 409                         snprintf(SNPARGS(action2, 0), "SkipTo %d",
 410                             f->fw_skipto_rule);
 411                         break;
 412                 default:
 413                         action = "UNKNOWN";
 414                         break;
 415                 }
 416         }
 417
 418         switch (nxt) {
 419         case IPPROTO_TCP:
 420                 len = snprintf(SNPARGS(proto, 0), "TCP [%s]",
 421                     ip6_sprintf(&ip6->ip6_src));
 422                 if (off > 0)
 423                         len += snprintf(SNPARGS(proto, len), ":%d ",
 424                             ntohs(tcp6->th_sport));
 425                 else
 426                         len += snprintf(SNPARGS(proto, len), " ");
 427                 len += snprintf(SNPARGS(proto, len), "[%s]",
 428                     ip6_sprintf(&ip6->ip6_dst));
 429                 if (off > 0)
 430                         snprintf(SNPARGS(proto, len), ":%d",
 431                             ntohs(tcp6->th_dport));
 432                 break;
 433         case IPPROTO_UDP:
 434                 len = snprintf(SNPARGS(proto, 0), "UDP [%s]",
 435                     ip6_sprintf(&ip6->ip6_src));
 436                 if (off > 0)
 437                         len += snprintf(SNPARGS(proto, len), ":%d ",
 438                             ntohs(udp->uh_sport));
 439                 else
 440                     len += snprintf(SNPARGS(proto, len), " ");
 441                 len += snprintf(SNPARGS(proto, len), "[%s]",
 442                     ip6_sprintf(&ip6->ip6_dst));
 443                 if (off > 0)
 444                         snprintf(SNPARGS(proto, len), ":%d",
 445                             ntohs(udp->uh_dport));
 446                 break;
 447         case IPPROTO_ICMPV6:
 448                 if (off > 0)
 449                         len = snprintf(SNPARGS(proto, 0), "IPV6-ICMP:%u.%u ",
 450                             icmp6->icmp6_type, icmp6->icmp6_code);
 451                 else
 452                         len = snprintf(SNPARGS(proto, 0), "IPV6-ICMP ");
 453                 len += snprintf(SNPARGS(proto, len), "[%s]",
 454                     ip6_sprintf(&ip6->ip6_src));
 455                 snprintf(SNPARGS(proto, len), " [%s]",
 456                     ip6_sprintf(&ip6->ip6_dst));
 457                 break;
 458         default:
 459                 len = snprintf(SNPARGS(proto, 0), "P:%d [%s]", nxt,
 460                     ip6_sprintf(&ip6->ip6_src));
 461                 snprintf(SNPARGS(proto, len), " [%s]",
 462                     ip6_sprintf(&ip6->ip6_dst));
 463                 break;
 464         }
 465
 466         if (oif)
 467                 log(LOG_SECURITY | LOG_INFO, "%s %s %s out via %s\n",
 468                     name, action, proto, if_name(oif));
 469         else if (rif)
 470                 log(LOG_SECURITY | LOG_INFO, "%s %s %s in via %s\n",
 471                     name, action, proto, if_name(rif));
 472         else
 473                 log(LOG_SECURITY | LOG_INFO, "%s %s %s",
 474                     name, action, proto);
 475         if (fw6_verbose_limit != 0 && count == fw6_verbose_limit)
 476             log(LOG_SECURITY | LOG_INFO, "ip6fw: limit reached on entry %d\n",
 477                 f ? f->fw_number : -1);
 478 }
 479
 480 /*
 481  * Parameters:
 482  *
 483  *      ip      Pointer to packet header (struct ip6_hdr *)
 484  *      hlen    Packet header length
 485  *      oif     Outgoing interface, or NULL if packet is incoming
 486  * #ifndef IP6FW_DIVERT_RESTART
 487  *      *cookie Ignore all divert/tee rules to this port (if non-zero)
 488  * #else
 489  *      *cookie Skip up to the first rule past this rule number;
 490  * #endif
 491  *      *m      The packet; we set to NULL when/if we nuke it.
 492  *
 493  * Return value:
 494  *
 495  *      0       The packet is to be accepted and routed normally OR
 496  *              the packet was denied/rejected and has been dropped;
 497  *              in the latter case, *m is equal to NULL upon return.
 498  *      port    Divert the packet to port.
 499  */
 500
 501 static int
 502 ip6_fw_chk(struct ip6_hdr **pip6,
 503         struct ifnet *oif, u_int16_t *cookie, struct mbuf **m)
 504 {
 505         struct ip6_fw_chain *chain;
 506         struct ip6_fw *rule = NULL;
 507         struct ip6_hdr *ip6 = *pip6;
 508         struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
 509         u_short offset = 0;
 510         int off = sizeof(struct ip6_hdr), nxt = ip6->ip6_nxt;
 511         u_short src_port, dst_port;
 512 #ifdef  IP6FW_DIVERT_RESTART
 513         u_int16_t skipto = *cookie;
 514 #else
 515         u_int16_t ignport = ntohs(*cookie);
 516 #endif
 517
 518         *cookie = 0;
 519         /*
 520          * Go down the chain, looking for enlightment
 521          * #ifdef IP6FW_DIVERT_RESTART
 522          * If we've been asked to start at a given rule immediatly, do so.
 523          * #endif
 524          */
 525         chain = LIST_FIRST(&ip6_fw_chain);
 526 #ifdef IP6FW_DIVERT_RESTART
 527         if (skipto) {
 528                 if (skipto >= 65535)
 529                         goto dropit;
 530                 while (chain && (chain->rule->fw_number <= skipto)) {
 531                         chain = LIST_NEXT(chain, chain);
 532                 }
 533                 if (! chain) goto dropit;
 534         }
 535 #endif /* IP6FW_DIVERT_RESTART */
 536         for (; chain; chain = LIST_NEXT(chain, chain)) {
 537                 struct ip6_fw *const f = chain->rule;
 538
 539                 if (oif) {
 540                         /* Check direction outbound */
 541                         if (!(f->fw_flg & IPV6_FW_F_OUT))
 542                                 continue;
 543                 } else {
 544                         /* Check direction inbound */
 545                         if (!(f->fw_flg & IPV6_FW_F_IN))
 546                                 continue;
 547                 }
 548
 549 #define IN6_ARE_ADDR_MASKEQUAL(x,y,z) (\
 550         (((x)->s6_addr32[0] & (y)->s6_addr32[0]) == (z)->s6_addr32[0]) && \
 551         (((x)->s6_addr32[1] & (y)->s6_addr32[1]) == (z)->s6_addr32[1]) && \
 552         (((x)->s6_addr32[2] & (y)->s6_addr32[2]) == (z)->s6_addr32[2]) && \
 553         (((x)->s6_addr32[3] & (y)->s6_addr32[3]) == (z)->s6_addr32[3]))
 554
 555                 /* If src-addr doesn't match, not this rule. */
 556                 if (((f->fw_flg & IPV6_FW_F_INVSRC) != 0) ^
 557                         (!IN6_ARE_ADDR_MASKEQUAL(&ip6->ip6_src,&f->fw_smsk,&f->fw_src)))
 558                         continue;
 559
 560                 /* If dest-addr doesn't match, not this rule. */
 561                 if (((f->fw_flg & IPV6_FW_F_INVDST) != 0) ^
 562                         (!IN6_ARE_ADDR_MASKEQUAL(&ip6->ip6_dst,&f->fw_dmsk,&f->fw_dst)))
 563                         continue;
 564
 565 #undef IN6_ARE_ADDR_MASKEQUAL
 566                 /* Interface check */
 567                 if ((f->fw_flg & IF6_FW_F_VIAHACK) == IF6_FW_F_VIAHACK) {
 568                         struct ifnet *const iface = oif ? oif : rif;
 569
 570                         /* Backwards compatibility hack for "via" */
 571                         if (!iface || !iface_match(iface,
 572                             &f->fw_in_if, f->fw_flg & IPV6_FW_F_OIFNAME))
 573                                 continue;
 574                 } else {
 575                         /* Check receive interface */
 576                         if ((f->fw_flg & IPV6_FW_F_IIFACE)
 577                             && (!rif || !iface_match(rif,
 578                               &f->fw_in_if, f->fw_flg & IPV6_FW_F_IIFNAME)))
 579                                 continue;
 580                         /* Check outgoing interface */
 581                         if ((f->fw_flg & IPV6_FW_F_OIFACE)
 582                             && (!oif || !iface_match(oif,
 583                               &f->fw_out_if, f->fw_flg & IPV6_FW_F_OIFNAME)))
 584                                 continue;
 585                 }
 586
 587                 /* Check IP options */
 588                 if (!ip6opts_match(&ip6, f, m, &off, &nxt, &offset))
 589                         continue;
 590
 591                 /* Fragments */
 592                 if ((f->fw_flg & IPV6_FW_F_FRAG) && !offset)
 593                         continue;
 594
 595                 /* Check protocol; if wildcard, match */
 596                 if (f->fw_prot == IPPROTO_IPV6)
 597                         goto got_match;
 598
 599                 /* If different, don't match */
 600                 if (nxt != f->fw_prot)
 601                         continue;
 602
 603 #define PULLUP_TO(len)  do {                                            \
 604                             if ((*m)->m_len < (len)                     \
 605                                 && (*m = m_pullup(*m, (len))) == 0) {   \
 606                                     goto dropit;                        \
 607                             }                                           \
 608                             *pip6 = ip6 = mtod(*m, struct ip6_hdr *);   \
 609                         } while (0)
 610
 611                 /* Protocol specific checks */
 612                 switch (nxt) {
 613                 case IPPROTO_TCP:
 614                     {
 615                         struct tcphdr *tcp6;
 616
 617                         if (offset == 1) {      /* cf. RFC 1858 */
 618                                 PULLUP_TO(off + 4); /* XXX ? */
 619                                 goto bogusfrag;
 620                         }
 621                         if (offset != 0) {
 622                                 /*
 623                                  * TCP flags and ports aren't available in this
 624                                  * packet -- if this rule specified either one,
 625                                  * we consider the rule a non-match.
 626                                  */
 627                                 if (f->fw_nports != 0 ||
 628                                     f->fw_tcpf != f->fw_tcpnf)
 629                                         continue;
 630
 631                                 break;
 632                         }
 633                         PULLUP_TO(off + 14);
 634                         tcp6 = (struct tcphdr *) ((caddr_t)ip6 + off);
 635                         if (((f->fw_tcpf != f->fw_tcpnf) ||
 636                            (f->fw_ipflg & IPV6_FW_IF_TCPEST))  &&
 637                            !tcp6flg_match(tcp6, f))
 638                                 continue;
 639                         src_port = ntohs(tcp6->th_sport);
 640                         dst_port = ntohs(tcp6->th_dport);
 641                         goto check_ports;
 642                     }
 643
 644                 case IPPROTO_UDP:
 645                     {
 646                         struct udphdr *udp;
 647
 648                         if (offset != 0) {
 649                                 /*
 650                                  * Port specification is unavailable -- if this
 651                                  * rule specifies a port, we consider the rule
 652                                  * a non-match.
 653                                  */
 654                                 if (f->fw_nports != 0)
 655                                         continue;
 656
 657                                 break;
 658                         }
 659                         PULLUP_TO(off + 4);
 660                         udp = (struct udphdr *) ((caddr_t)ip6 + off);
 661                         src_port = ntohs(udp->uh_sport);
 662                         dst_port = ntohs(udp->uh_dport);
 663 check_ports:
 664                         if (!port_match6(&f->fw_pts[0],
 665                             IPV6_FW_GETNSRCP(f), src_port,
 666                             f->fw_flg & IPV6_FW_F_SRNG))
 667                                 continue;
 668                         if (!port_match6(&f->fw_pts[IPV6_FW_GETNSRCP(f)],
 669                             IPV6_FW_GETNDSTP(f), dst_port,
 670                             f->fw_flg & IPV6_FW_F_DRNG))
 671                                 continue;
 672                         break;
 673                     }
 674
 675                 case IPPROTO_ICMPV6:
 676                     {
 677                         struct icmp6_hdr *icmp;
 678
 679                         if (offset != 0)        /* Type isn't valid */
 680                                 break;
 681                         PULLUP_TO(off + 2);
 682                         icmp = (struct icmp6_hdr *) ((caddr_t)ip6 + off);
 683                         if (!icmp6type_match(icmp, f))
 684                                 continue;
 685                         break;
 686                     }
 687 #undef PULLUP_TO
 688
 689 bogusfrag:
 690                         if (fw6_verbose)
 691                                 ip6fw_report(NULL, ip6, rif, oif, off, nxt);
 692                         goto dropit;
 693                 }
 694
 695 got_match:
 696 #ifndef IP6FW_DIVERT_RESTART
 697                 /* Ignore divert/tee rule if socket port is "ignport" */
 698                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 699                 case IPV6_FW_F_DIVERT:
 700                 case IPV6_FW_F_TEE:
 701                         if (f->fw_divert_port == ignport)
 702                                 continue;       /* ignore this rule */
 703                         break;
 704                 }
 705
 706 #endif /* IP6FW_DIVERT_RESTART */
 707                 /* Update statistics */
 708                 f->fw_pcnt += 1;
 709                 f->fw_bcnt += ntohs(ip6->ip6_plen);
 710                 f->timestamp = time_second;
 711
 712                 /* Log to console if desired */
 713                 if ((f->fw_flg & IPV6_FW_F_PRN) && fw6_verbose)
 714                         ip6fw_report(f, ip6, rif, oif, off, nxt);
 715
 716                 /* Take appropriate action */
 717                 switch (f->fw_flg & IPV6_FW_F_COMMAND) {
 718                 case IPV6_FW_F_ACCEPT:
 719                         return(0);
 720                 case IPV6_FW_F_COUNT:
 721                         continue;
 722                 case IPV6_FW_F_DIVERT:
 723 #ifdef IP6FW_DIVERT_RESTART
 724                         *cookie = f->fw_number;
 725 #else
 726                         *cookie = htons(f->fw_divert_port);
 727 #endif /* IP6FW_DIVERT_RESTART */
 728                         return(f->fw_divert_port);
 729                 case IPV6_FW_F_TEE:
 730                         /*
 731                          * XXX someday tee packet here, but beware that you
 732                          * can't use m_copym() or m_copypacket() because
 733                          * the divert input routine modifies the mbuf
 734                          * (and these routines only increment reference
 735                          * counts in the case of mbuf clusters), so need
 736                          * to write custom routine.
 737                          */
 738                         continue;
 739                 case IPV6_FW_F_SKIPTO:
 740 #ifdef DIAGNOSTIC
 741                         while (chain->chain.le_next
 742                             && chain->chain.le_next->rule->fw_number
 743                                 < f->fw_skipto_rule)
 744 #else
 745                         while (chain->chain.le_next->rule->fw_number
 746                             < f->fw_skipto_rule)
 747 #endif
 748                                 chain = chain->chain.le_next;
 749                         continue;
 750                 }
 751
 752                 /* Deny/reject this packet using this rule */
 753                 rule = f;
 754                 break;
 755         }
 756
 757 #ifdef DIAGNOSTIC
 758         /* Rule 65535 should always be there and should always match */
 759         if (!chain)
 760                 panic("ip6_fw: chain");
 761 #endif
 762
 763         /*
 764          * At this point, we're going to drop the packet.
 765          * Send a reject notice if all of the following are true:
 766          *
 767          * - The packet matched a reject rule
 768          * - The packet is not an ICMP packet, or is an ICMP query packet
 769          * - The packet is not a multicast or broadcast packet
 770          */
 771         if ((rule->fw_flg & IPV6_FW_F_COMMAND) == IPV6_FW_F_REJECT
 772             && (nxt != IPPROTO_ICMPV6 || is_icmp6_query(ip6, off))
 773             && !((*m)->m_flags & (M_BCAST|M_MCAST))
 774             && !IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 775                 switch (rule->fw_reject_code) {
 776                 case IPV6_FW_REJECT_RST:
 777                   {
 778                         struct tcphdr *const tcp =
 779                                 (struct tcphdr *) ((caddr_t)ip6 + off);
 780                         struct {
 781                                 struct ip6_hdr ip6;
 782                                 struct tcphdr th;
 783                         } ti;
 784                         tcp_seq ack, seq;
 785                         int flags;
 786
 787                         if (offset != 0 || (tcp->th_flags & TH_RST))
 788                                 break;
 789
 790                         ti.ip6 = *ip6;
 791                         ti.th = *tcp;
 792                         NTOHL(ti.th.th_seq);
 793                         NTOHL(ti.th.th_ack);
 794                         ti.ip6.ip6_nxt = IPPROTO_TCP;
 795                         if (ti.th.th_flags & TH_ACK) {
 796                                 ack = 0;
 797                                 seq = ti.th.th_ack;
 798                                 flags = TH_RST;
 799                         } else {
 800                                 ack = ti.th.th_seq;
 801                                 if (((*m)->m_flags & M_PKTHDR) != 0) {
 802                                         ack += (*m)->m_pkthdr.len - off
 803                                                 - (ti.th.th_off << 2);
 804                                 } else if (ip6->ip6_plen) {
 805                                         ack += ntohs(ip6->ip6_plen) + sizeof(*ip6)
 806                                                 - off - (ti.th.th_off << 2);
 807                                 } else {
 808                                         m_freem(*m);
 809                                         *m = 0;
 810                                         break;
 811                                 }
 812                                 seq = 0;
 813                                 flags = TH_RST|TH_ACK;
 814                         }
 815                         bcopy(&ti, ip6, sizeof(ti));
 816                         tcp_respond(NULL, ip6, (struct tcphdr *)(ip6 + 1),
 817                                 *m, ack, seq, flags);
 818                         *m = NULL;
 819                         break;
 820                   }
 821                 default:        /* Send an ICMP unreachable using code */
 822                         if (oif)
 823                                 (*m)->m_pkthdr.rcvif = oif;
 824                         icmp6_error(*m, ICMP6_DST_UNREACH,
 825                             rule->fw_reject_code, 0);
 826                         *m = NULL;
 827                         break;
 828                 }
 829         }
 830
 831 dropit:
 832         /*
 833          * Finally, drop the packet.
 834          */
 835         if (*m) {
 836                 m_freem(*m);
 837                 *m = NULL;
 838         }
 839         return(0);
 840 }
 841
 842 static int
 843 add_entry6(struct ip6_fw_head *chainptr, struct ip6_fw *frwl)
 844 {
 845         struct ip6_fw *ftmp = 0;
 846         struct ip6_fw_chain *fwc = 0, *fcp, *fcpl = 0;
 847         u_short nbr = 0;
 848         int s;
 849
 850         fwc = malloc(sizeof *fwc, M_IP6FW, M_INTWAIT);
 851         ftmp = malloc(sizeof *ftmp, M_IP6FW, M_INTWAIT);
 852
 853         bcopy(frwl, ftmp, sizeof(struct ip6_fw));
 854         ftmp->fw_in_if.fu_via_if.name[IP6FW_IFNLEN - 1] = '\0';
 855         ftmp->fw_pcnt = 0L;
 856         ftmp->fw_bcnt = 0L;
 857         fwc->rule = ftmp;
 858
 859         s = splnet();
 860
 861         if (!chainptr->lh_first) {
 862                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 863                 splx(s);
 864                 return(0);
 865         } else if (ftmp->fw_number == (u_short)-1) {
 866                 if (fwc)  free(fwc, M_IP6FW);
 867                 if (ftmp) free(ftmp, M_IP6FW);
 868                 splx(s);
 869                 dprintf(("%s bad rule number\n", err_prefix));
 870                 return (EINVAL);
 871         }
 872
 873         /* If entry number is 0, find highest numbered rule and add 100 */
 874         if (ftmp->fw_number == 0) {
 875                 for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 876                         if (fcp->rule->fw_number != (u_short)-1)
 877                                 nbr = fcp->rule->fw_number;
 878                         else
 879                                 break;
 880                 }
 881                 if (nbr < (u_short)-1 - 100)
 882                         nbr += 100;
 883                 ftmp->fw_number = nbr;
 884         }
 885
 886         /* Got a valid number; now insert it, keeping the list ordered */
 887         for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 888                 if (fcp->rule->fw_number > ftmp->fw_number) {
 889                         if (fcpl) {
 890                                 LIST_INSERT_AFTER(fcpl, fwc, chain);
 891                         } else {
 892                                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 893                         }
 894                         break;
 895                 } else {
 896                         fcpl = fcp;
 897                 }
 898         }
 899
 900         splx(s);
 901         return (0);
 902 }
 903
 904 static int
 905 del_entry6(struct ip6_fw_head *chainptr, u_short number)
 906 {
 907         struct ip6_fw_chain *fcp;
 908         int s;
 909
 910         s = splnet();
 911
 912         fcp = chainptr->lh_first;
 913         if (number != (u_short)-1) {
 914                 for (; fcp; fcp = fcp->chain.le_next) {
 915                         if (fcp->rule->fw_number == number) {
 916                                 LIST_REMOVE(fcp, chain);
 917                                 splx(s);
 918                                 free(fcp->rule, M_IP6FW);
 919                                 free(fcp, M_IP6FW);
 920                                 return 0;
 921                         }
 922                 }
 923         }
 924
 925         splx(s);
 926         return (EINVAL);
 927 }
 928
 929 static int
 930 zero_entry6(struct mbuf *m)
 931 {
 932         struct ip6_fw *frwl;
 933         struct ip6_fw_chain *fcp;
 934         int s;
 935
 936         if (m && m->m_len != 0) {
 937                 if (m->m_len != sizeof(struct ip6_fw))
 938                         return(EINVAL);
 939                 frwl = mtod(m, struct ip6_fw *);
 940         }
 941         else
 942                 frwl = NULL;
 943
 944         /*
 945          *      It's possible to insert multiple chain entries with the
 946          *      same number, so we don't stop after finding the first
 947          *      match if zeroing a specific entry.
 948          */
 949         s = splnet();
 950         for (fcp = ip6_fw_chain.lh_first; fcp; fcp = fcp->chain.le_next)
 951                 if (!frwl || frwl->fw_number == fcp->rule->fw_number) {
 952                         fcp->rule->fw_bcnt = fcp->rule->fw_pcnt = 0;
 953                         fcp->rule->timestamp = 0;
 954                 }
 955         splx(s);
 956
 957         if (fw6_verbose) {
 958                 if (frwl)
 959                         log(LOG_SECURITY | LOG_NOTICE,
 960                             "ip6fw: Entry %d cleared.\n", frwl->fw_number);
 961                 else
 962                         log(LOG_SECURITY | LOG_NOTICE,
 963                             "ip6fw: Accounting cleared.\n");
 964         }
 965
 966         return(0);
 967 }
 968
 969 static struct ip6_fw *
 970 check_ip6fw_mbuf(struct mbuf *m)
 971 {
 972         /* Check length */
 973         if (m->m_len != sizeof(struct ip6_fw)) {
 974                 dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
 975                     sizeof(struct ip6_fw)));
 976                 return (NULL);
 977         }
 978         return(check_ip6fw_struct(mtod(m, struct ip6_fw *)));
 979 }
 980
 981 static struct ip6_fw *
 982 check_ip6fw_struct(struct ip6_fw *frwl)
 983 {
 984         /* Check for invalid flag bits */
 985         if ((frwl->fw_flg & ~IPV6_FW_F_MASK) != 0) {
 986                 dprintf(("%s undefined flag bits set (flags=%x)\n",
 987                     err_prefix, frwl->fw_flg));
 988                 return (NULL);
 989         }
 990         /* Must apply to incoming or outgoing (or both) */
 991         if (!(frwl->fw_flg & (IPV6_FW_F_IN | IPV6_FW_F_OUT))) {
 992                 dprintf(("%s neither in nor out\n", err_prefix));
 993                 return (NULL);
 994         }
 995         /* Empty interface name is no good */
 996         if (((frwl->fw_flg & IPV6_FW_F_IIFNAME)
 997               && !*frwl->fw_in_if.fu_via_if.name)
 998             || ((frwl->fw_flg & IPV6_FW_F_OIFNAME)
 999               && !*frwl->fw_out_if.fu_via_if.name)) {
1000                 dprintf(("%s empty interface name\n", err_prefix));
1001                 return (NULL);
1002         }
1003         /* Sanity check interface matching */
1004         if ((frwl->fw_flg & IF6_FW_F_VIAHACK) == IF6_FW_F_VIAHACK) {
1005                 ;               /* allow "via" backwards compatibility */
1006         } else if ((frwl->fw_flg & IPV6_FW_F_IN)
1007             && (frwl->fw_flg & IPV6_FW_F_OIFACE)) {
1008                 dprintf(("%s outgoing interface check on incoming\n",
1009                     err_prefix));
1010                 return (NULL);
1011         }
1012         /* Sanity check port ranges */
1013         if ((frwl->fw_flg & IPV6_FW_F_SRNG) && IPV6_FW_GETNSRCP(frwl) < 2) {
1014                 dprintf(("%s src range set but n_src_p=%d\n",
1015                     err_prefix, IPV6_FW_GETNSRCP(frwl)));
1016                 return (NULL);
1017         }
1018         if ((frwl->fw_flg & IPV6_FW_F_DRNG) && IPV6_FW_GETNDSTP(frwl) < 2) {
1019                 dprintf(("%s dst range set but n_dst_p=%d\n",
1020                     err_prefix, IPV6_FW_GETNDSTP(frwl)));
1021                 return (NULL);
1022         }
1023         if (IPV6_FW_GETNSRCP(frwl) + IPV6_FW_GETNDSTP(frwl) > IPV6_FW_MAX_PORTS) {
1024                 dprintf(("%s too many ports (%d+%d)\n",
1025                     err_prefix, IPV6_FW_GETNSRCP(frwl), IPV6_FW_GETNDSTP(frwl)));
1026                 return (NULL);
1027         }
1028         /*
1029          *      Protocols other than TCP/UDP don't use port range
1030          */
1031         if ((frwl->fw_prot != IPPROTO_TCP) &&
1032             (frwl->fw_prot != IPPROTO_UDP) &&
1033             (IPV6_FW_GETNSRCP(frwl) || IPV6_FW_GETNDSTP(frwl))) {
1034                 dprintf(("%s port(s) specified for non TCP/UDP rule\n",
1035                     err_prefix));
1036                 return(NULL);
1037         }
1038
1039         /*
1040          *      Rather than modify the entry to make such entries work,
1041          *      we reject this rule and require user level utilities
1042          *      to enforce whatever policy they deem appropriate.
1043          */
1044         if ((frwl->fw_src.s6_addr32[0] & (~frwl->fw_smsk.s6_addr32[0])) ||
1045                 (frwl->fw_src.s6_addr32[1] & (~frwl->fw_smsk.s6_addr32[1])) ||
1046                 (frwl->fw_src.s6_addr32[2] & (~frwl->fw_smsk.s6_addr32[2])) ||
1047                 (frwl->fw_src.s6_addr32[3] & (~frwl->fw_smsk.s6_addr32[3])) ||
1048                 (frwl->fw_dst.s6_addr32[0] & (~frwl->fw_dmsk.s6_addr32[0])) ||
1049                 (frwl->fw_dst.s6_addr32[1] & (~frwl->fw_dmsk.s6_addr32[1])) ||
1050                 (frwl->fw_dst.s6_addr32[2] & (~frwl->fw_dmsk.s6_addr32[2])) ||
1051                 (frwl->fw_dst.s6_addr32[3] & (~frwl->fw_dmsk.s6_addr32[3]))) {
1052                 dprintf(("%s rule never matches\n", err_prefix));
1053                 return(NULL);
1054         }
1055
1056         if ((frwl->fw_flg & IPV6_FW_F_FRAG) &&
1057                 (frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
1058                 if (frwl->fw_nports) {
1059                         dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
1060                         return(NULL);
1061                 }
1062                 if (frwl->fw_prot == IPPROTO_TCP &&
1063                         frwl->fw_tcpf != frwl->fw_tcpnf) {
1064                         dprintf(("%s cannot mix 'frag' with TCP flags\n", err_prefix));
1065                         return(NULL);
1066                 }
1067         }
1068
1069         /* Check command specific stuff */
1070         switch (frwl->fw_flg & IPV6_FW_F_COMMAND)
1071         {
1072         case IPV6_FW_F_REJECT:
1073                 if (frwl->fw_reject_code >= 0x100
1074                     && !(frwl->fw_prot == IPPROTO_TCP
1075                       && frwl->fw_reject_code == IPV6_FW_REJECT_RST)) {
1076                         dprintf(("%s unknown reject code\n", err_prefix));
1077                         return(NULL);
1078                 }
1079                 break;
1080         case IPV6_FW_F_DIVERT:          /* Diverting to port zero is invalid */
1081         case IPV6_FW_F_TEE:
1082                 if (frwl->fw_divert_port == 0) {
1083                         dprintf(("%s can't divert to port 0\n", err_prefix));
1084                         return (NULL);
1085                 }
1086                 break;
1087         case IPV6_FW_F_DENY:
1088         case IPV6_FW_F_ACCEPT:
1089         case IPV6_FW_F_COUNT:
1090         case IPV6_FW_F_SKIPTO:
1091                 break;
1092         default:
1093                 dprintf(("%s invalid command\n", err_prefix));
1094                 return(NULL);
1095         }
1096
1097         return frwl;
1098 }
1099
1100 static int
1101 ip6_fw_ctl(int stage, struct mbuf **mm)
1102 {
1103         int error;
1104         struct mbuf *m;
1105
1106         if (stage == IPV6_FW_GET) {
1107                 struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1108                 *mm = m = m_get(MB_WAIT, MT_DATA); /* XXX */
1109                 if (!m)
1110                         return(ENOBUFS);
1111                 if (sizeof *(fcp->rule) > MLEN) {
1112                         MCLGET(m, MB_WAIT);
1113                         if ((m->m_flags & M_EXT) == 0) {
1114                                 m_free(m);
1115                                 return(ENOBUFS);
1116                         }
1117                 }
1118                 for (; fcp; fcp = fcp->chain.le_next) {
1119                         bcopy(fcp->rule, m->m_data, sizeof *(fcp->rule));
1120                         m->m_len = sizeof *(fcp->rule);
1121                         m->m_next = m_get(MB_WAIT, MT_DATA); /* XXX */
1122                         if (!m->m_next) {
1123                                 m_freem(*mm);
1124                                 return(ENOBUFS);
1125                         }
1126                         m = m->m_next;
1127                         if (sizeof *(fcp->rule) > MLEN) {
1128                                 MCLGET(m, MB_WAIT);
1129                                 if ((m->m_flags & M_EXT) == 0) {
1130                                         m_freem(*mm);
1131                                         return(ENOBUFS);
1132                                 }
1133                         }
1134                         m->m_len = 0;
1135                 }
1136                 return (0);
1137         }
1138         m = *mm;
1139         /* only allow get calls if secure mode > 2 */
1140         if (securelevel > 2) {
1141                 if (m) {
1142                         (void)m_freem(m);
1143                         *mm = 0;
1144                 }
1145                 return(EPERM);
1146         }
1147         if (stage == IPV6_FW_FLUSH) {
1148                 while (ip6_fw_chain.lh_first != NULL &&
1149                     ip6_fw_chain.lh_first->rule->fw_number != (u_short)-1) {
1150                         struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1151                         int s = splnet();
1152                         LIST_REMOVE(ip6_fw_chain.lh_first, chain);
1153                         splx(s);
1154                         free(fcp->rule, M_IP6FW);
1155                         free(fcp, M_IP6FW);
1156                 }
1157                 if (m) {
1158                         (void)m_freem(m);
1159                         *mm = 0;
1160                 }
1161                 return (0);
1162         }
1163         if (stage == IPV6_FW_ZERO) {
1164                 error = zero_entry6(m);
1165                 if (m) {
1166                         (void)m_freem(m);
1167                         *mm = 0;
1168                 }
1169                 return (error);
1170         }
1171         if (m == NULL) {
1172                 printf("%s NULL mbuf ptr\n", err_prefix);
1173                 return (EINVAL);
1174         }
1175
1176         if (stage == IPV6_FW_ADD) {
1177                 struct ip6_fw *frwl = check_ip6fw_mbuf(m);
1178
1179                 if (!frwl)
1180                         error = EINVAL;
1181                 else
1182                         error = add_entry6(&ip6_fw_chain, frwl);
1183                 if (m) {
1184                         (void)m_freem(m);
1185                         *mm = 0;
1186                 }
1187                 return error;
1188         }
1189         if (stage == IPV6_FW_DEL) {
1190                 if (m->m_len != sizeof(struct ip6_fw)) {
1191                         dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
1192                             sizeof(struct ip6_fw)));
1193                         error = EINVAL;
1194                 } else if (mtod(m, struct ip6_fw *)->fw_number == (u_short)-1) {
1195                         dprintf(("%s can't delete rule 65535\n", err_prefix));
1196                         error = EINVAL;
1197                 } else
1198                         error = del_entry6(&ip6_fw_chain,
1199                             mtod(m, struct ip6_fw *)->fw_number);
1200                 if (m) {
1201                         (void)m_freem(m);
1202                         *mm = 0;
1203                 }
1204                 return error;
1205         }
1206
1207         dprintf(("%s unknown request %d\n", err_prefix, stage));
1208         if (m) {
1209                 (void)m_freem(m);
1210                 *mm = 0;
1211         }
1212         return (EINVAL);
1213 }
1214
1215 void
1216 ip6_fw_init(void)
1217 {
1218         struct ip6_fw default_rule;
1219
1220         ip6_fw_chk_ptr = ip6_fw_chk;
1221         ip6_fw_ctl_ptr = ip6_fw_ctl;
1222         LIST_INIT(&ip6_fw_chain);
1223
1224         bzero(&default_rule, sizeof default_rule);
1225         default_rule.fw_prot = IPPROTO_IPV6;
1226         default_rule.fw_number = (u_short)-1;
1227 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1228         default_rule.fw_flg |= IPV6_FW_F_ACCEPT;
1229 #else
1230         default_rule.fw_flg |= IPV6_FW_F_DENY;
1231 #endif
1232         default_rule.fw_flg |= IPV6_FW_F_IN | IPV6_FW_F_OUT;
1233         if (check_ip6fw_struct(&default_rule) == NULL ||
1234                 add_entry6(&ip6_fw_chain, &default_rule))
1235                 panic(__FUNCTION__);
1236
1237         printf("IPv6 packet filtering initialized, ");
1238 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1239         printf("default to accept, ");
1240 #endif
1241 #ifndef IPV6FIREWALL_VERBOSE
1242         printf("logging disabled\n");
1243 #else
1244         if (fw6_verbose_limit == 0)
1245                 printf("unlimited logging\n");
1246         else
1247                 printf("logging limited to %d packets/entry\n",
1248                     fw6_verbose_limit);
1249 #endif
1250 }
1251
1252 static ip6_fw_chk_t *old_chk_ptr;
1253 static ip6_fw_ctl_t *old_ctl_ptr;
1254
1255 static int
1256 ip6fw_modevent(module_t mod, int type, void *unused)
1257 {
1258         int s;
1259
1260         switch (type) {
1261         case MOD_LOAD:
1262                 s = splnet();
1263
1264                 old_chk_ptr = ip6_fw_chk_ptr;
1265                 old_ctl_ptr = ip6_fw_ctl_ptr;
1266
1267                 ip6_fw_init();
1268                 splx(s);
1269                 return 0;
1270         case MOD_UNLOAD:
1271                 s = splnet();
1272                 ip6_fw_chk_ptr =  old_chk_ptr;
1273                 ip6_fw_ctl_ptr =  old_ctl_ptr;
1274                 while (LIST_FIRST(&ip6_fw_chain) != NULL) {
1275                         struct ip6_fw_chain *fcp = LIST_FIRST(&ip6_fw_chain);
1276                         LIST_REMOVE(LIST_FIRST(&ip6_fw_chain), chain);
1277                         free(fcp->rule, M_IP6FW);
1278                         free(fcp, M_IP6FW);
1279                 }
1280
1281                 splx(s);
1282                 printf("IPv6 firewall unloaded\n");
1283                 return 0;
1284         default:
1285                 break;
1286         }
1287         return 0;
1288 }
1289
1290 static moduledata_t ip6fwmod = {
1291         "ip6fw",
1292         ip6fw_modevent,
1293         0
1294 };
1295 DECLARE_MODULE(ip6fw, ip6fwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);