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 /*      $KAME: ip6_fw.c,v 1.21 2001/01/24 01:25:32 itojun Exp $ */
   3
   4 /*
   5  * Copyright (C) 1998, 1999, 2000 and 2001 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * Copyright (c) 1993 Daniel Boulet
  35  * Copyright (c) 1994 Ugen J.S.Antsilevich
  36  * Copyright (c) 1996 Alex Nash
  37  *
  38  * Redistribution and use in source forms, with and without modification,
  39  * are permitted provided that this entire comment appears intact.
  40  *
  41  * Redistribution in binary form may occur without any restrictions.
  42  * Obviously, it would be nice if you gave credit where credit is due
  43  * but requiring it would be too onerous.
  44  *
  45  * This software is provided ``AS IS'' without any warranties of any kind.
  46  */
  47
  48 /*
  49  * Implement IPv6 packet firewall
  50  */
  51
  52 #if !defined(KLD_MODULE)
  53 #include "opt_ip6fw.h"
  54 #include "opt_inet.h"
  55 #include "opt_inet6.h"
  56 #endif
  57
  58 #ifdef IP6DIVERT
  59 #error "NOT SUPPORTED IPV6 DIVERT"
  60 #endif
  61 #ifdef IP6FW_DIVERT_RESTART
  62 #error "NOT SUPPORTED IPV6 DIVERT"
  63 #endif
  64
  65 #include <sys/param.h>
  66 #include <sys/systm.h>
  67 #include <sys/malloc.h>
  68 #include <sys/mbuf.h>
  69 #include <sys/queue.h>
  70 #include <sys/kernel.h>
  71 #include <sys/socket.h>
  72 #include <sys/socketvar.h>
  73 #include <sys/syslog.h>
  74 #include <sys/time.h>
  75 #include <net/if.h>
  76 #include <net/route.h>
  77 #include <netinet/in_systm.h>
  78 #include <netinet/in.h>
  79 #include <netinet/ip.h>
  80
  81 #include <netinet/ip6.h>
  82 #include <netinet6/ip6_var.h>
  83 #include <netinet6/in6_var.h>
  84 #include <netinet/icmp6.h>
  85
  86 #include <netinet/in_pcb.h>
  87
  88 #include <netinet6/ip6_fw.h>
  89 #include <netinet/ip_var.h>
  90 #include <netinet/tcp.h>
  91 #include <netinet/tcp_seq.h>
  92 #include <netinet/tcp_timer.h>
  93 #include <netinet/tcp_var.h>
  94 #include <netinet/udp.h>
  95
  96 #include <sys/sysctl.h>
  97
  98 #include <net/net_osdep.h>
  99
 100 MALLOC_DEFINE(M_IP6FW, "Ip6Fw/Ip6Acct", "Ip6Fw/Ip6Acct chain's");
 101
 102 static int fw6_debug = 1;
 103 #ifdef IPV6FIREWALL_VERBOSE
 104 static int fw6_verbose = 1;
 105 #else
 106 static int fw6_verbose = 0;
 107 #endif
 108 #ifdef IPV6FIREWALL_VERBOSE_LIMIT
 109 static int fw6_verbose_limit = IPV6FIREWALL_VERBOSE_LIMIT;
 110 #else
 111 static int fw6_verbose_limit = 0;
 112 #endif
 113
 114 LIST_HEAD (ip6_fw_head, ip6_fw_chain) ip6_fw_chain;
 115
 116 #ifdef SYSCTL_NODE
 117 SYSCTL_DECL(_net_inet6_ip6);
 118 SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
 119 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, enable, CTLFLAG_RW,
 120         &ip6_fw_enable, 0, "Enable ip6fw");
 121 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, debug, CTLFLAG_RW, &fw6_debug, 0, "");
 122 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, verbose, CTLFLAG_RW, &fw6_verbose, 0, "");
 123 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, &fw6_verbose_limit, 0, "");
 124 #endif
 125
 126 #define dprintf(a)      do {                                            \
 127                                 if (fw6_debug)                          \
 128                                         printf a;                       \
 129                         } while (0)
 130 #define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
 131
 132 static int      add_entry6 __P((struct ip6_fw_head *chainptr, struct ip6_fw *frwl));
 133 static int      del_entry6 __P((struct ip6_fw_head *chainptr, u_short number));
 134 static int      zero_entry6 __P((struct mbuf *m));
 135 static struct ip6_fw *check_ip6fw_struct __P((struct ip6_fw *m));
 136 static struct ip6_fw *check_ip6fw_mbuf __P((struct mbuf *fw));
 137 static int      ip6opts_match __P((struct ip6_hdr **ip6, struct ip6_fw *f,
 138                                    struct mbuf **m,
 139                                    int *off, int *nxt, u_short *offset));
 140 static int      port_match6 __P((u_short *portptr, int nports, u_short port,
 141                                 int range_flag));
 142 static int      tcp6flg_match __P((struct tcphdr *tcp6, struct ip6_fw *f));
 143 static int      icmp6type_match __P((struct icmp6_hdr *  icmp, struct ip6_fw * f));
 144 static void     ip6fw_report __P((struct ip6_fw *f, struct ip6_hdr *ip6,
 145                                 struct ifnet *rif, struct ifnet *oif, int off, int nxt));
 146
 147 static int      ip6_fw_chk __P((struct ip6_hdr **pip6,
 148                         struct ifnet *oif, u_int16_t *cookie, struct mbuf **m));
 149 static int      ip6_fw_ctl __P((int stage, struct mbuf **mm));
 150
 151 static char err_prefix[] = "ip6_fw_ctl:";
 152
 153 /*
 154  * Returns 1 if the port is matched by the vector, 0 otherwise
 155  */
 156 static
 157 __inline int
 158 port_match6(u_short *portptr, int nports, u_short port, int range_flag)
 159 {
 160         if (!nports)
 161                 return 1;
 162         if (range_flag) {
 163                 if (portptr[0] <= port && port <= portptr[1]) {
 164                         return 1;
 165                 }
 166                 nports -= 2;
 167                 portptr += 2;
 168         }
 169         while (nports-- > 0) {
 170                 if (*portptr++ == port) {
 171                         return 1;
 172                 }
 173         }
 174         return 0;
 175 }
 176
 177 static int
 178 tcp6flg_match(struct tcphdr *tcp6, struct ip6_fw *f)
 179 {
 180         u_char          flg_set, flg_clr;
 181
 182         /*
 183          * If an established connection is required, reject packets that
 184          * have only SYN of RST|ACK|SYN set.  Otherwise, fall through to
 185          * other flag requirements.
 186          */
 187         if ((f->fw_ipflg & IPV6_FW_IF_TCPEST) &&
 188             ((tcp6->th_flags & (IPV6_FW_TCPF_RST | IPV6_FW_TCPF_ACK |
 189             IPV6_FW_TCPF_SYN)) == IPV6_FW_TCPF_SYN))
 190                 return 0;
 191
 192         flg_set = tcp6->th_flags & f->fw_tcpf;
 193         flg_clr = tcp6->th_flags & f->fw_tcpnf;
 194
 195         if (flg_set != f->fw_tcpf)
 196                 return 0;
 197         if (flg_clr)
 198                 return 0;
 199
 200         return 1;
 201 }
 202
 203 static int
 204 icmp6type_match(struct icmp6_hdr *icmp6, struct ip6_fw *f)
 205 {
 206         int type;
 207
 208         if (!(f->fw_flg & IPV6_FW_F_ICMPBIT))
 209                 return(1);
 210
 211         type = icmp6->icmp6_type;
 212
 213         /* check for matching type in the bitmap */
 214         if (type < IPV6_FW_ICMPTYPES_DIM * sizeof(unsigned) * 8 &&
 215                 (f->fw_icmp6types[type / (sizeof(unsigned) * 8)] &
 216                 (1U << (type % (8 * sizeof(unsigned))))))
 217                 return(1);
 218
 219         return(0); /* no match */
 220 }
 221
 222 static int
 223 is_icmp6_query(struct ip6_hdr *ip6, int off)
 224 {
 225         const struct icmp6_hdr *icmp6;
 226         int icmp6_type;
 227
 228         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 229         icmp6_type = icmp6->icmp6_type;
 230
 231         if (icmp6_type == ICMP6_ECHO_REQUEST ||
 232             icmp6_type == ICMP6_MEMBERSHIP_QUERY ||
 233             icmp6_type == ICMP6_WRUREQUEST ||
 234             icmp6_type == ICMP6_FQDN_QUERY ||
 235             icmp6_type == ICMP6_NI_QUERY)
 236                 return(1);
 237
 238         return(0);
 239 }
 240
 241 static int
 242 ip6opts_match(struct ip6_hdr **pip6, struct ip6_fw *f, struct mbuf **m,
 243               int *off, int *nxt, u_short *offset)
 244 {
 245         int len;
 246         struct ip6_hdr *ip6 = *pip6;
 247         struct ip6_ext *ip6e;
 248         u_char  opts, nopts, nopts_sve;
 249
 250         opts = f->fw_ip6opt;
 251         nopts = nopts_sve = f->fw_ip6nopt;
 252
 253         *nxt = ip6->ip6_nxt;
 254         *off = sizeof(struct ip6_hdr);
 255         len = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr);
 256         while (*off < len) {
 257                 ip6e = (struct ip6_ext *)((caddr_t) ip6 + *off);
 258                 if ((*m)->m_len < *off + sizeof(*ip6e))
 259                         goto opts_check;        /* XXX */
 260
 261                 switch(*nxt) {
 262                 case IPPROTO_FRAGMENT:
 263                         if ((*m)->m_len >= *off + sizeof(struct ip6_frag)) {
 264                                 struct ip6_frag *ip6f;
 265
 266                                 ip6f = (struct ip6_frag *) ((caddr_t)ip6 + *off);
 267                                 *offset = ip6f->ip6f_offlg & IP6F_OFF_MASK;
 268                         }
 269                         opts &= ~IPV6_FW_IP6OPT_FRAG;
 270                         nopts &= ~IPV6_FW_IP6OPT_FRAG;
 271                         *off += sizeof(struct ip6_frag);
 272                         break;
 273                 case IPPROTO_AH:
 274                         opts &= ~IPV6_FW_IP6OPT_AH;
 275                         nopts &= ~IPV6_FW_IP6OPT_AH;
 276                         *off += (ip6e->ip6e_len + 2) << 2;
 277                         break;
 278                 default:
 279                         switch (*nxt) {
 280                         case IPPROTO_HOPOPTS:
 281                                 opts &= ~IPV6_FW_IP6OPT_HOPOPT;
 282                                 nopts &= ~IPV6_FW_IP6OPT_HOPOPT;
 283                                 break;
 284                         case IPPROTO_ROUTING:
 285                                 opts &= ~IPV6_FW_IP6OPT_ROUTE;
 286                                 nopts &= ~IPV6_FW_IP6OPT_ROUTE;
 287                                 break;
 288                         case IPPROTO_ESP:
 289                                 opts &= ~IPV6_FW_IP6OPT_ESP;
 290                                 nopts &= ~IPV6_FW_IP6OPT_ESP;
 291                                 break;
 292                         case IPPROTO_NONE:
 293                                 opts &= ~IPV6_FW_IP6OPT_NONXT;
 294                                 nopts &= ~IPV6_FW_IP6OPT_NONXT;
 295                                 goto opts_check;
 296                                 break;
 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                                 break;
 304                         }
 305                         *off += (ip6e->ip6e_len + 1) << 3;
 306                         break;
 307                 }
 308                 *nxt = ip6e->ip6e_nxt;
 309
 310         }
 311  opts_check:
 312         if (f->fw_ip6opt == f->fw_ip6nopt)      /* XXX */
 313                 return 1;
 314
 315         if (opts == 0 && nopts == nopts_sve)
 316                 return 1;
 317         else
 318                 return 0;
 319 }
 320
 321 static
 322 __inline int
 323 iface_match(struct ifnet *ifp, union ip6_fw_if *ifu, int byname)
 324 {
 325         /* Check by name or by IP address */
 326         if (byname) {
 327                 /* Check unit number (-1 is wildcard) */
 328                 if (ifu->fu_via_if.unit != -1
 329                     && ifp->if_unit != ifu->fu_via_if.unit)
 330                         return(0);
 331                 /* Check name */
 332                 if (strncmp(ifp->if_name, ifu->fu_via_if.name, IP6FW_IFNLEN))
 333                         return(0);
 334                 return(1);
 335         } else if (!IN6_IS_ADDR_UNSPECIFIED(&ifu->fu_via_ip6)) {        /* Zero == wildcard */
 336                 struct ifaddr *ia;
 337
 338                 for (ia = ifp->if_addrlist.tqh_first; ia; ia = ia->ifa_list.tqe_next)
 339                 {
 340
 341                         if (ia->ifa_addr == NULL)
 342                                 continue;
 343                         if (ia->ifa_addr->sa_family != AF_INET6)
 344                                 continue;
 345                         if (!IN6_ARE_ADDR_EQUAL(&ifu->fu_via_ip6,
 346                             &(((struct sockaddr_in6 *)
 347                             (ia->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                         NTOHL(ti.th.th_seq);
 789                         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_DONTWAIT);
 847         ftmp = malloc(sizeof *ftmp, M_IP6FW, M_DONTWAIT);
 848         if (!fwc || !ftmp) {
 849                 dprintf(("%s malloc said no\n", err_prefix));
 850                 if (fwc)  free(fwc, M_IP6FW);
 851                 if (ftmp) free(ftmp, M_IP6FW);
 852                 return (ENOSPC);
 853         }
 854
 855         bcopy(frwl, ftmp, sizeof(struct ip6_fw));
 856         ftmp->fw_in_if.fu_via_if.name[IP6FW_IFNLEN - 1] = '\0';
 857         ftmp->fw_pcnt = 0L;
 858         ftmp->fw_bcnt = 0L;
 859         fwc->rule = ftmp;
 860
 861         s = splnet();
 862
 863         if (!chainptr->lh_first) {
 864                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 865                 splx(s);
 866                 return(0);
 867         } else if (ftmp->fw_number == (u_short)-1) {
 868                 if (fwc)  free(fwc, M_IP6FW);
 869                 if (ftmp) free(ftmp, M_IP6FW);
 870                 splx(s);
 871                 dprintf(("%s bad rule number\n", err_prefix));
 872                 return (EINVAL);
 873         }
 874
 875         /* If entry number is 0, find highest numbered rule and add 100 */
 876         if (ftmp->fw_number == 0) {
 877                 for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 878                         if (fcp->rule->fw_number != (u_short)-1)
 879                                 nbr = fcp->rule->fw_number;
 880                         else
 881                                 break;
 882                 }
 883                 if (nbr < (u_short)-1 - 100)
 884                         nbr += 100;
 885                 ftmp->fw_number = nbr;
 886         }
 887
 888         /* Got a valid number; now insert it, keeping the list ordered */
 889         for (fcp = chainptr->lh_first; fcp; fcp = fcp->chain.le_next) {
 890                 if (fcp->rule->fw_number > ftmp->fw_number) {
 891                         if (fcpl) {
 892                                 LIST_INSERT_AFTER(fcpl, fwc, chain);
 893                         } else {
 894                                 LIST_INSERT_HEAD(chainptr, fwc, chain);
 895                         }
 896                         break;
 897                 } else {
 898                         fcpl = fcp;
 899                 }
 900         }
 901
 902         splx(s);
 903         return (0);
 904 }
 905
 906 static int
 907 del_entry6(struct ip6_fw_head *chainptr, u_short number)
 908 {
 909         struct ip6_fw_chain *fcp;
 910         int s;
 911
 912         s = splnet();
 913
 914         fcp = chainptr->lh_first;
 915         if (number != (u_short)-1) {
 916                 for (; fcp; fcp = fcp->chain.le_next) {
 917                         if (fcp->rule->fw_number == number) {
 918                                 LIST_REMOVE(fcp, chain);
 919                                 splx(s);
 920                                 free(fcp->rule, M_IP6FW);
 921                                 free(fcp, M_IP6FW);
 922                                 return 0;
 923                         }
 924                 }
 925         }
 926
 927         splx(s);
 928         return (EINVAL);
 929 }
 930
 931 static int
 932 zero_entry6(struct mbuf *m)
 933 {
 934         struct ip6_fw *frwl;
 935         struct ip6_fw_chain *fcp;
 936         int s;
 937
 938         if (m && m->m_len != 0) {
 939                 if (m->m_len != sizeof(struct ip6_fw))
 940                         return(EINVAL);
 941                 frwl = mtod(m, struct ip6_fw *);
 942         }
 943         else
 944                 frwl = NULL;
 945
 946         /*
 947          *      It's possible to insert multiple chain entries with the
 948          *      same number, so we don't stop after finding the first
 949          *      match if zeroing a specific entry.
 950          */
 951         s = splnet();
 952         for (fcp = ip6_fw_chain.lh_first; fcp; fcp = fcp->chain.le_next)
 953                 if (!frwl || frwl->fw_number == fcp->rule->fw_number) {
 954                         fcp->rule->fw_bcnt = fcp->rule->fw_pcnt = 0;
 955                         fcp->rule->timestamp = 0;
 956                 }
 957         splx(s);
 958
 959         if (fw6_verbose) {
 960                 if (frwl)
 961                         log(LOG_SECURITY | LOG_NOTICE,
 962                             "ip6fw: Entry %d cleared.\n", frwl->fw_number);
 963                 else
 964                         log(LOG_SECURITY | LOG_NOTICE,
 965                             "ip6fw: Accounting cleared.\n");
 966         }
 967
 968         return(0);
 969 }
 970
 971 static struct ip6_fw *
 972 check_ip6fw_mbuf(struct mbuf *m)
 973 {
 974         /* Check length */
 975         if (m->m_len != sizeof(struct ip6_fw)) {
 976                 dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
 977                     sizeof(struct ip6_fw)));
 978                 return (NULL);
 979         }
 980         return(check_ip6fw_struct(mtod(m, struct ip6_fw *)));
 981 }
 982
 983 static struct ip6_fw *
 984 check_ip6fw_struct(struct ip6_fw *frwl)
 985 {
 986         /* Check for invalid flag bits */
 987         if ((frwl->fw_flg & ~IPV6_FW_F_MASK) != 0) {
 988                 dprintf(("%s undefined flag bits set (flags=%x)\n",
 989                     err_prefix, frwl->fw_flg));
 990                 return (NULL);
 991         }
 992         /* Must apply to incoming or outgoing (or both) */
 993         if (!(frwl->fw_flg & (IPV6_FW_F_IN | IPV6_FW_F_OUT))) {
 994                 dprintf(("%s neither in nor out\n", err_prefix));
 995                 return (NULL);
 996         }
 997         /* Empty interface name is no good */
 998         if (((frwl->fw_flg & IPV6_FW_F_IIFNAME)
 999               && !*frwl->fw_in_if.fu_via_if.name)
1000             || ((frwl->fw_flg & IPV6_FW_F_OIFNAME)
1001               && !*frwl->fw_out_if.fu_via_if.name)) {
1002                 dprintf(("%s empty interface name\n", err_prefix));
1003                 return (NULL);
1004         }
1005         /* Sanity check interface matching */
1006         if ((frwl->fw_flg & IF6_FW_F_VIAHACK) == IF6_FW_F_VIAHACK) {
1007                 ;               /* allow "via" backwards compatibility */
1008         } else if ((frwl->fw_flg & IPV6_FW_F_IN)
1009             && (frwl->fw_flg & IPV6_FW_F_OIFACE)) {
1010                 dprintf(("%s outgoing interface check on incoming\n",
1011                     err_prefix));
1012                 return (NULL);
1013         }
1014         /* Sanity check port ranges */
1015         if ((frwl->fw_flg & IPV6_FW_F_SRNG) && IPV6_FW_GETNSRCP(frwl) < 2) {
1016                 dprintf(("%s src range set but n_src_p=%d\n",
1017                     err_prefix, IPV6_FW_GETNSRCP(frwl)));
1018                 return (NULL);
1019         }
1020         if ((frwl->fw_flg & IPV6_FW_F_DRNG) && IPV6_FW_GETNDSTP(frwl) < 2) {
1021                 dprintf(("%s dst range set but n_dst_p=%d\n",
1022                     err_prefix, IPV6_FW_GETNDSTP(frwl)));
1023                 return (NULL);
1024         }
1025         if (IPV6_FW_GETNSRCP(frwl) + IPV6_FW_GETNDSTP(frwl) > IPV6_FW_MAX_PORTS) {
1026                 dprintf(("%s too many ports (%d+%d)\n",
1027                     err_prefix, IPV6_FW_GETNSRCP(frwl), IPV6_FW_GETNDSTP(frwl)));
1028                 return (NULL);
1029         }
1030         /*
1031          *      Protocols other than TCP/UDP don't use port range
1032          */
1033         if ((frwl->fw_prot != IPPROTO_TCP) &&
1034             (frwl->fw_prot != IPPROTO_UDP) &&
1035             (IPV6_FW_GETNSRCP(frwl) || IPV6_FW_GETNDSTP(frwl))) {
1036                 dprintf(("%s port(s) specified for non TCP/UDP rule\n",
1037                     err_prefix));
1038                 return(NULL);
1039         }
1040
1041         /*
1042          *      Rather than modify the entry to make such entries work,
1043          *      we reject this rule and require user level utilities
1044          *      to enforce whatever policy they deem appropriate.
1045          */
1046         if ((frwl->fw_src.s6_addr32[0] & (~frwl->fw_smsk.s6_addr32[0])) ||
1047                 (frwl->fw_src.s6_addr32[1] & (~frwl->fw_smsk.s6_addr32[1])) ||
1048                 (frwl->fw_src.s6_addr32[2] & (~frwl->fw_smsk.s6_addr32[2])) ||
1049                 (frwl->fw_src.s6_addr32[3] & (~frwl->fw_smsk.s6_addr32[3])) ||
1050                 (frwl->fw_dst.s6_addr32[0] & (~frwl->fw_dmsk.s6_addr32[0])) ||
1051                 (frwl->fw_dst.s6_addr32[1] & (~frwl->fw_dmsk.s6_addr32[1])) ||
1052                 (frwl->fw_dst.s6_addr32[2] & (~frwl->fw_dmsk.s6_addr32[2])) ||
1053                 (frwl->fw_dst.s6_addr32[3] & (~frwl->fw_dmsk.s6_addr32[3]))) {
1054                 dprintf(("%s rule never matches\n", err_prefix));
1055                 return(NULL);
1056         }
1057
1058         if ((frwl->fw_flg & IPV6_FW_F_FRAG) &&
1059                 (frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
1060                 if (frwl->fw_nports) {
1061                         dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
1062                         return(NULL);
1063                 }
1064                 if (frwl->fw_prot == IPPROTO_TCP &&
1065                         frwl->fw_tcpf != frwl->fw_tcpnf) {
1066                         dprintf(("%s cannot mix 'frag' with TCP flags\n", err_prefix));
1067                         return(NULL);
1068                 }
1069         }
1070
1071         /* Check command specific stuff */
1072         switch (frwl->fw_flg & IPV6_FW_F_COMMAND)
1073         {
1074         case IPV6_FW_F_REJECT:
1075                 if (frwl->fw_reject_code >= 0x100
1076                     && !(frwl->fw_prot == IPPROTO_TCP
1077                       && frwl->fw_reject_code == IPV6_FW_REJECT_RST)) {
1078                         dprintf(("%s unknown reject code\n", err_prefix));
1079                         return(NULL);
1080                 }
1081                 break;
1082         case IPV6_FW_F_DIVERT:          /* Diverting to port zero is invalid */
1083         case IPV6_FW_F_TEE:
1084                 if (frwl->fw_divert_port == 0) {
1085                         dprintf(("%s can't divert to port 0\n", err_prefix));
1086                         return (NULL);
1087                 }
1088                 break;
1089         case IPV6_FW_F_DENY:
1090         case IPV6_FW_F_ACCEPT:
1091         case IPV6_FW_F_COUNT:
1092         case IPV6_FW_F_SKIPTO:
1093                 break;
1094         default:
1095                 dprintf(("%s invalid command\n", err_prefix));
1096                 return(NULL);
1097         }
1098
1099         return frwl;
1100 }
1101
1102 static int
1103 ip6_fw_ctl(int stage, struct mbuf **mm)
1104 {
1105         int error;
1106         struct mbuf *m;
1107
1108         if (stage == IPV6_FW_GET) {
1109                 struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1110                 *mm = m = m_get(M_WAIT, MT_DATA); /* XXX */
1111                 if (!m)
1112                         return(ENOBUFS);
1113                 if (sizeof *(fcp->rule) > MLEN) {
1114                         MCLGET(m, M_WAIT);
1115                         if ((m->m_flags & M_EXT) == 0) {
1116                                 m_free(m);
1117                                 return(ENOBUFS);
1118                         }
1119                 }
1120                 for (; fcp; fcp = fcp->chain.le_next) {
1121                         bcopy(fcp->rule, m->m_data, sizeof *(fcp->rule));
1122                         m->m_len = sizeof *(fcp->rule);
1123                         m->m_next = m_get(M_WAIT, MT_DATA); /* XXX */
1124                         if (!m->m_next) {
1125                                 m_freem(*mm);
1126                                 return(ENOBUFS);
1127                         }
1128                         m = m->m_next;
1129                         if (sizeof *(fcp->rule) > MLEN) {
1130                                 MCLGET(m, M_WAIT);
1131                                 if ((m->m_flags & M_EXT) == 0) {
1132                                         m_freem(*mm);
1133                                         return(ENOBUFS);
1134                                 }
1135                         }
1136                         m->m_len = 0;
1137                 }
1138                 return (0);
1139         }
1140         m = *mm;
1141         /* only allow get calls if secure mode > 2 */
1142         if (securelevel > 2) {
1143                 if (m) {
1144                         (void)m_freem(m);
1145                         *mm = 0;
1146                 }
1147                 return(EPERM);
1148         }
1149         if (stage == IPV6_FW_FLUSH) {
1150                 while (ip6_fw_chain.lh_first != NULL &&
1151                     ip6_fw_chain.lh_first->rule->fw_number != (u_short)-1) {
1152                         struct ip6_fw_chain *fcp = ip6_fw_chain.lh_first;
1153                         int s = splnet();
1154                         LIST_REMOVE(ip6_fw_chain.lh_first, chain);
1155                         splx(s);
1156                         free(fcp->rule, M_IP6FW);
1157                         free(fcp, M_IP6FW);
1158                 }
1159                 if (m) {
1160                         (void)m_freem(m);
1161                         *mm = 0;
1162                 }
1163                 return (0);
1164         }
1165         if (stage == IPV6_FW_ZERO) {
1166                 error = zero_entry6(m);
1167                 if (m) {
1168                         (void)m_freem(m);
1169                         *mm = 0;
1170                 }
1171                 return (error);
1172         }
1173         if (m == NULL) {
1174                 printf("%s NULL mbuf ptr\n", err_prefix);
1175                 return (EINVAL);
1176         }
1177
1178         if (stage == IPV6_FW_ADD) {
1179                 struct ip6_fw *frwl = check_ip6fw_mbuf(m);
1180
1181                 if (!frwl)
1182                         error = EINVAL;
1183                 else
1184                         error = add_entry6(&ip6_fw_chain, frwl);
1185                 if (m) {
1186                         (void)m_freem(m);
1187                         *mm = 0;
1188                 }
1189                 return error;
1190         }
1191         if (stage == IPV6_FW_DEL) {
1192                 if (m->m_len != sizeof(struct ip6_fw)) {
1193                         dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
1194                             sizeof(struct ip6_fw)));
1195                         error = EINVAL;
1196                 } else if (mtod(m, struct ip6_fw *)->fw_number == (u_short)-1) {
1197                         dprintf(("%s can't delete rule 65535\n", err_prefix));
1198                         error = EINVAL;
1199                 } else
1200                         error = del_entry6(&ip6_fw_chain,
1201                             mtod(m, struct ip6_fw *)->fw_number);
1202                 if (m) {
1203                         (void)m_freem(m);
1204                         *mm = 0;
1205                 }
1206                 return error;
1207         }
1208
1209         dprintf(("%s unknown request %d\n", err_prefix, stage));
1210         if (m) {
1211                 (void)m_freem(m);
1212                 *mm = 0;
1213         }
1214         return (EINVAL);
1215 }
1216
1217 void
1218 ip6_fw_init(void)
1219 {
1220         struct ip6_fw default_rule;
1221
1222         ip6_fw_chk_ptr = ip6_fw_chk;
1223         ip6_fw_ctl_ptr = ip6_fw_ctl;
1224         LIST_INIT(&ip6_fw_chain);
1225
1226         bzero(&default_rule, sizeof default_rule);
1227         default_rule.fw_prot = IPPROTO_IPV6;
1228         default_rule.fw_number = (u_short)-1;
1229 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1230         default_rule.fw_flg |= IPV6_FW_F_ACCEPT;
1231 #else
1232         default_rule.fw_flg |= IPV6_FW_F_DENY;
1233 #endif
1234         default_rule.fw_flg |= IPV6_FW_F_IN | IPV6_FW_F_OUT;
1235         if (check_ip6fw_struct(&default_rule) == NULL ||
1236                 add_entry6(&ip6_fw_chain, &default_rule))
1237                 panic(__FUNCTION__);
1238
1239         printf("IPv6 packet filtering initialized, ");
1240 #ifdef IPV6FIREWALL_DEFAULT_TO_ACCEPT
1241         printf("default to accept, ");
1242 #endif
1243 #ifndef IPV6FIREWALL_VERBOSE
1244         printf("logging disabled\n");
1245 #else
1246         if (fw6_verbose_limit == 0)
1247                 printf("unlimited logging\n");
1248         else
1249                 printf("logging limited to %d packets/entry\n",
1250                     fw6_verbose_limit);
1251 #endif
1252 }
1253
1254 static ip6_fw_chk_t *old_chk_ptr;
1255 static ip6_fw_ctl_t *old_ctl_ptr;
1256
1257 static int
1258 ip6fw_modevent(module_t mod, int type, void *unused)
1259 {
1260         int s;
1261
1262         switch (type) {
1263         case MOD_LOAD:
1264                 s = splnet();
1265
1266                 old_chk_ptr = ip6_fw_chk_ptr;
1267                 old_ctl_ptr = ip6_fw_ctl_ptr;
1268
1269                 ip6_fw_init();
1270                 splx(s);
1271                 return 0;
1272         case MOD_UNLOAD:
1273                 s = splnet();
1274                 ip6_fw_chk_ptr =  old_chk_ptr;
1275                 ip6_fw_ctl_ptr =  old_ctl_ptr;
1276                 while (LIST_FIRST(&ip6_fw_chain) != NULL) {
1277                         struct ip6_fw_chain *fcp = LIST_FIRST(&ip6_fw_chain);
1278                         LIST_REMOVE(LIST_FIRST(&ip6_fw_chain), chain);
1279                         free(fcp->rule, M_IP6FW);
1280                         free(fcp, M_IP6FW);
1281                 }
1282
1283                 splx(s);
1284                 printf("IPv6 firewall unloaded\n");
1285                 return 0;
1286         default:
1287                 break;
1288         }
1289         return 0;
1290 }
1291
1292 static moduledata_t ip6fwmod = {
1293         "ip6fw",
1294         ip6fw_modevent,
1295         0
1296 };
1297 DECLARE_MODULE(ip6fw, ip6fwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);