The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netpfil/ipfw/nptv6/nptv6.c

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    1 /*-
    2  * Copyright (c) 2016 Yandex LLC
    3  * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  *
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   26  */
   27 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD$");
   30 
   31 #include <sys/param.h>
   32 #include <sys/systm.h>
   33 #include <sys/counter.h>
   34 #include <sys/eventhandler.h>
   35 #include <sys/errno.h>
   36 #include <sys/kernel.h>
   37 #include <sys/lock.h>
   38 #include <sys/malloc.h>
   39 #include <sys/mbuf.h>
   40 #include <sys/module.h>
   41 #include <sys/rmlock.h>
   42 #include <sys/rwlock.h>
   43 #include <sys/socket.h>
   44 #include <sys/queue.h>
   45 #include <sys/syslog.h>
   46 #include <sys/sysctl.h>
   47 
   48 #include <net/if.h>
   49 #include <net/if_var.h>
   50 #include <net/netisr.h>
   51 #include <net/pfil.h>
   52 #include <net/vnet.h>
   53 
   54 #include <netinet/in.h>
   55 #include <netinet/ip_var.h>
   56 #include <netinet/ip_fw.h>
   57 #include <netinet/ip6.h>
   58 #include <netinet/icmp6.h>
   59 #include <netinet6/in6_var.h>
   60 #include <netinet6/ip6_var.h>
   61 
   62 #include <netpfil/ipfw/ip_fw_private.h>
   63 #include <netpfil/ipfw/nptv6/nptv6.h>
   64 
   65 VNET_DEFINE_STATIC(uint16_t, nptv6_eid) = 0;
   66 #define V_nptv6_eid     VNET(nptv6_eid)
   67 #define IPFW_TLV_NPTV6_NAME     IPFW_TLV_EACTION_NAME(V_nptv6_eid)
   68 
   69 static eventhandler_tag nptv6_ifaddr_event;
   70 
   71 static struct nptv6_cfg *nptv6_alloc_config(const char *name, uint8_t set);
   72 static void nptv6_free_config(struct nptv6_cfg *cfg);
   73 static struct nptv6_cfg *nptv6_find(struct namedobj_instance *ni,
   74     const char *name, uint8_t set);
   75 static int nptv6_rewrite_internal(struct nptv6_cfg *cfg, struct mbuf **mp,
   76     int offset);
   77 static int nptv6_rewrite_external(struct nptv6_cfg *cfg, struct mbuf **mp,
   78     int offset);
   79 
   80 #define NPTV6_LOOKUP(chain, cmd)        \
   81     (struct nptv6_cfg *)SRV_OBJECT((chain), (cmd)->arg1)
   82 
   83 #ifndef IN6_MASK_ADDR
   84 #define IN6_MASK_ADDR(a, m)     do { \
   85         (a)->s6_addr32[0] &= (m)->s6_addr32[0]; \
   86         (a)->s6_addr32[1] &= (m)->s6_addr32[1]; \
   87         (a)->s6_addr32[2] &= (m)->s6_addr32[2]; \
   88         (a)->s6_addr32[3] &= (m)->s6_addr32[3]; \
   89 } while (0)
   90 #endif
   91 #ifndef IN6_ARE_MASKED_ADDR_EQUAL
   92 #define IN6_ARE_MASKED_ADDR_EQUAL(d, a, m)      (       \
   93         (((d)->s6_addr32[0] ^ (a)->s6_addr32[0]) & (m)->s6_addr32[0]) == 0 && \
   94         (((d)->s6_addr32[1] ^ (a)->s6_addr32[1]) & (m)->s6_addr32[1]) == 0 && \
   95         (((d)->s6_addr32[2] ^ (a)->s6_addr32[2]) & (m)->s6_addr32[2]) == 0 && \
   96         (((d)->s6_addr32[3] ^ (a)->s6_addr32[3]) & (m)->s6_addr32[3]) == 0 )
   97 #endif
   98 
   99 #if 0
  100 #define NPTV6_DEBUG(fmt, ...)   do {                    \
  101         printf("%s: " fmt "\n", __func__, ## __VA_ARGS__);      \
  102 } while (0)
  103 #define NPTV6_IPDEBUG(fmt, ...) do {                    \
  104         char _s[INET6_ADDRSTRLEN], _d[INET6_ADDRSTRLEN];        \
  105         printf("%s: " fmt "\n", __func__, ## __VA_ARGS__);      \
  106 } while (0)
  107 #else
  108 #define NPTV6_DEBUG(fmt, ...)
  109 #define NPTV6_IPDEBUG(fmt, ...)
  110 #endif
  111 
  112 static int
  113 nptv6_getlasthdr(struct nptv6_cfg *cfg, struct mbuf *m, int *offset)
  114 {
  115         struct ip6_hdr *ip6;
  116         struct ip6_hbh *hbh;
  117         int proto, hlen;
  118 
  119         hlen = (offset == NULL) ? 0: *offset;
  120         if (m->m_len < hlen)
  121                 return (-1);
  122         ip6 = mtodo(m, hlen);
  123         hlen += sizeof(*ip6);
  124         proto = ip6->ip6_nxt;
  125         while (proto == IPPROTO_HOPOPTS || proto == IPPROTO_ROUTING ||
  126             proto == IPPROTO_DSTOPTS) {
  127                 hbh = mtodo(m, hlen);
  128                 if (m->m_len < hlen)
  129                         return (-1);
  130                 proto = hbh->ip6h_nxt;
  131                 hlen += (hbh->ip6h_len + 1) << 3;
  132         }
  133         if (offset != NULL)
  134                 *offset = hlen;
  135         return (proto);
  136 }
  137 
  138 static int
  139 nptv6_translate_icmpv6(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
  140 {
  141         struct icmp6_hdr *icmp6;
  142         struct ip6_hdr *ip6;
  143         struct mbuf *m;
  144 
  145         m = *mp;
  146         if (offset > m->m_len)
  147                 return (-1);
  148         icmp6 = mtodo(m, offset);
  149         NPTV6_DEBUG("ICMPv6 type %d", icmp6->icmp6_type);
  150         switch (icmp6->icmp6_type) {
  151         case ICMP6_DST_UNREACH:
  152         case ICMP6_PACKET_TOO_BIG:
  153         case ICMP6_TIME_EXCEEDED:
  154         case ICMP6_PARAM_PROB:
  155                 break;
  156         case ICMP6_ECHO_REQUEST:
  157         case ICMP6_ECHO_REPLY:
  158                 /* nothing to translate */
  159                 return (0);
  160         default:
  161                 /*
  162                  * XXX: We can add some checks to not translate NDP and MLD
  163                  * messages. Currently user must explicitly allow these message
  164                  * types, otherwise packets will be dropped.
  165                  */
  166                 return (-1);
  167         }
  168         offset += sizeof(*icmp6);
  169         if (offset + sizeof(*ip6) > m->m_pkthdr.len)
  170                 return (-1);
  171         if (offset + sizeof(*ip6) > m->m_len)
  172                 *mp = m = m_pullup(m, offset + sizeof(*ip6));
  173         if (m == NULL)
  174                 return (-1);
  175         ip6 = mtodo(m, offset);
  176         NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
  177             inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
  178             inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
  179             ip6->ip6_nxt);
  180         if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_src,
  181             &cfg->external, &cfg->mask))
  182                 return (nptv6_rewrite_external(cfg, mp, offset));
  183         else if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
  184             &cfg->internal, &cfg->mask))
  185                 return (nptv6_rewrite_internal(cfg, mp, offset));
  186         /*
  187          * Addresses in the inner IPv6 header doesn't matched to
  188          * our prefixes.
  189          */
  190         return (-1);
  191 }
  192 
  193 static int
  194 nptv6_search_index(struct nptv6_cfg *cfg, struct in6_addr *a)
  195 {
  196         int idx;
  197 
  198         if (cfg->flags & NPTV6_48PLEN)
  199                 return (3);
  200 
  201         /* Search suitable word index for adjustment */
  202         for (idx = 4; idx < 8; idx++)
  203                 if (a->s6_addr16[idx] != 0xffff)
  204                         break;
  205         /*
  206          * RFC 6296 p3.7: If an NPTv6 Translator discovers a datagram with
  207          * an IID of all-zeros while performing address mapping, that
  208          * datagram MUST be dropped, and an ICMPv6 Parameter Problem error
  209          * SHOULD be generated.
  210          */
  211         if (idx == 8 ||
  212             (a->s6_addr32[2] == 0 && a->s6_addr32[3] == 0))
  213                 return (-1);
  214         return (idx);
  215 }
  216 
  217 static void
  218 nptv6_copy_addr(struct in6_addr *src, struct in6_addr *dst,
  219     struct in6_addr *mask)
  220 {
  221         int i;
  222 
  223         for (i = 0; i < 8 && mask->s6_addr8[i] != 0; i++) {
  224                 dst->s6_addr8[i] &=  ~mask->s6_addr8[i];
  225                 dst->s6_addr8[i] |= src->s6_addr8[i] & mask->s6_addr8[i];
  226         }
  227 }
  228 
  229 static int
  230 nptv6_rewrite_internal(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
  231 {
  232         struct in6_addr *addr;
  233         struct ip6_hdr *ip6;
  234         int idx, proto;
  235         uint16_t adj;
  236 
  237         ip6 = mtodo(*mp, offset);
  238         NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
  239             inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
  240             inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
  241             ip6->ip6_nxt);
  242         if (offset == 0)
  243                 addr = &ip6->ip6_src;
  244         else {
  245                 /*
  246                  * When we rewriting inner IPv6 header, we need to rewrite
  247                  * destination address back to external prefix. The datagram in
  248                  * the ICMPv6 payload should looks like it was send from
  249                  * external prefix.
  250                  */
  251                 addr = &ip6->ip6_dst;
  252         }
  253         idx = nptv6_search_index(cfg, addr);
  254         if (idx < 0) {
  255                 /*
  256                  * Do not send ICMPv6 error when offset isn't zero.
  257                  * This means we are rewriting inner IPv6 header in the
  258                  * ICMPv6 error message.
  259                  */
  260                 if (offset == 0) {
  261                         icmp6_error2(*mp, ICMP6_DST_UNREACH,
  262                             ICMP6_DST_UNREACH_ADDR, 0, (*mp)->m_pkthdr.rcvif);
  263                         *mp = NULL;
  264                 }
  265                 return (IP_FW_DENY);
  266         }
  267         adj = addr->s6_addr16[idx];
  268         nptv6_copy_addr(&cfg->external, addr, &cfg->mask);
  269         adj = cksum_add(adj, cfg->adjustment);
  270         if (adj == 0xffff)
  271                 adj = 0;
  272         addr->s6_addr16[idx] = adj;
  273         if (offset == 0) {
  274                 /*
  275                  * We may need to translate addresses in the inner IPv6
  276                  * header for ICMPv6 error messages.
  277                  */
  278                 proto = nptv6_getlasthdr(cfg, *mp, &offset);
  279                 if (proto < 0 || (proto == IPPROTO_ICMPV6 &&
  280                     nptv6_translate_icmpv6(cfg, mp, offset) != 0))
  281                         return (IP_FW_DENY);
  282                 NPTV6STAT_INC(cfg, in2ex);
  283         }
  284         return (0);
  285 }
  286 
  287 static int
  288 nptv6_rewrite_external(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
  289 {
  290         struct in6_addr *addr;
  291         struct ip6_hdr *ip6;
  292         int idx, proto;
  293         uint16_t adj;
  294 
  295         ip6 = mtodo(*mp, offset);
  296         NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
  297             inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
  298             inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
  299             ip6->ip6_nxt);
  300         if (offset == 0)
  301                 addr = &ip6->ip6_dst;
  302         else {
  303                 /*
  304                  * When we rewriting inner IPv6 header, we need to rewrite
  305                  * source address back to internal prefix. The datagram in
  306                  * the ICMPv6 payload should looks like it was send from
  307                  * internal prefix.
  308                  */
  309                 addr = &ip6->ip6_src;
  310         }
  311         idx = nptv6_search_index(cfg, addr);
  312         if (idx < 0) {
  313                 /*
  314                  * Do not send ICMPv6 error when offset isn't zero.
  315                  * This means we are rewriting inner IPv6 header in the
  316                  * ICMPv6 error message.
  317                  */
  318                 if (offset == 0) {
  319                         icmp6_error2(*mp, ICMP6_DST_UNREACH,
  320                             ICMP6_DST_UNREACH_ADDR, 0, (*mp)->m_pkthdr.rcvif);
  321                         *mp = NULL;
  322                 }
  323                 return (IP_FW_DENY);
  324         }
  325         adj = addr->s6_addr16[idx];
  326         nptv6_copy_addr(&cfg->internal, addr, &cfg->mask);
  327         adj = cksum_add(adj, ~cfg->adjustment);
  328         if (adj == 0xffff)
  329                 adj = 0;
  330         addr->s6_addr16[idx] = adj;
  331         if (offset == 0) {
  332                 /*
  333                  * We may need to translate addresses in the inner IPv6
  334                  * header for ICMPv6 error messages.
  335                  */
  336                 proto = nptv6_getlasthdr(cfg, *mp, &offset);
  337                 if (proto < 0 || (proto == IPPROTO_ICMPV6 &&
  338                     nptv6_translate_icmpv6(cfg, mp, offset) != 0))
  339                         return (IP_FW_DENY);
  340                 NPTV6STAT_INC(cfg, ex2in);
  341         }
  342         return (0);
  343 }
  344 
  345 /*
  346  * ipfw external action handler.
  347  */
  348 static int
  349 ipfw_nptv6(struct ip_fw_chain *chain, struct ip_fw_args *args,
  350     ipfw_insn *cmd, int *done)
  351 {
  352         struct ip6_hdr *ip6;
  353         struct nptv6_cfg *cfg;
  354         ipfw_insn *icmd;
  355         int ret;
  356 
  357         *done = 0; /* try next rule if not matched */
  358         ret = IP_FW_DENY;
  359         icmd = cmd + 1;
  360         if (cmd->opcode != O_EXTERNAL_ACTION ||
  361             cmd->arg1 != V_nptv6_eid ||
  362             icmd->opcode != O_EXTERNAL_INSTANCE ||
  363             (cfg = NPTV6_LOOKUP(chain, icmd)) == NULL ||
  364             (cfg->flags & NPTV6_READY) == 0)
  365                 return (ret);
  366         /*
  367          * We need act as router, so when forwarding is disabled -
  368          * do nothing.
  369          */
  370         if (V_ip6_forwarding == 0 || args->f_id.addr_type != 6)
  371                 return (ret);
  372         /*
  373          * NOTE: we expect ipfw_chk() did m_pullup() up to upper level
  374          * protocol's headers. Also we skip some checks, that ip6_input(),
  375          * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did.
  376          */
  377         ip6 = mtod(args->m, struct ip6_hdr *);
  378         NPTV6_IPDEBUG("eid %u, oid %u, %s -> %s %d",
  379             cmd->arg1, icmd->arg1,
  380             inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
  381             inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
  382             ip6->ip6_nxt);
  383         if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_src,
  384             &cfg->internal, &cfg->mask)) {
  385                 /*
  386                  * XXX: Do not translate packets when both src and dst
  387                  * are from internal prefix.
  388                  */
  389                 if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
  390                     &cfg->internal, &cfg->mask))
  391                         return (ret);
  392                 ret = nptv6_rewrite_internal(cfg, &args->m, 0);
  393         } else if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
  394             &cfg->external, &cfg->mask))
  395                 ret = nptv6_rewrite_external(cfg, &args->m, 0);
  396         else
  397                 return (ret);
  398         /*
  399          * If address wasn't rewrited - free mbuf and terminate the search.
  400          */
  401         if (ret != 0) {
  402                 if (args->m != NULL) {
  403                         m_freem(args->m);
  404                         args->m = NULL; /* mark mbuf as consumed */
  405                 }
  406                 NPTV6STAT_INC(cfg, dropped);
  407                 *done = 1;
  408         } else {
  409                 /* Terminate the search if one_pass is set */
  410                 *done = V_fw_one_pass;
  411                 /* Update args->f_id when one_pass is off */
  412                 if (*done == 0) {
  413                         ip6 = mtod(args->m, struct ip6_hdr *);
  414                         args->f_id.src_ip6 = ip6->ip6_src;
  415                         args->f_id.dst_ip6 = ip6->ip6_dst;
  416                 }
  417         }
  418         return (ret);
  419 }
  420 
  421 static struct nptv6_cfg *
  422 nptv6_alloc_config(const char *name, uint8_t set)
  423 {
  424         struct nptv6_cfg *cfg;
  425 
  426         cfg = malloc(sizeof(struct nptv6_cfg), M_IPFW, M_WAITOK | M_ZERO);
  427         COUNTER_ARRAY_ALLOC(cfg->stats, NPTV6STATS, M_WAITOK);
  428         cfg->no.name = cfg->name;
  429         cfg->no.etlv = IPFW_TLV_NPTV6_NAME;
  430         cfg->no.set = set;
  431         strlcpy(cfg->name, name, sizeof(cfg->name));
  432         return (cfg);
  433 }
  434 
  435 static void
  436 nptv6_free_config(struct nptv6_cfg *cfg)
  437 {
  438 
  439         COUNTER_ARRAY_FREE(cfg->stats, NPTV6STATS);
  440         free(cfg, M_IPFW);
  441 }
  442 
  443 static void
  444 nptv6_export_config(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
  445     ipfw_nptv6_cfg *uc)
  446 {
  447 
  448         uc->internal = cfg->internal;
  449         if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
  450                 memcpy(uc->if_name, cfg->if_name, IF_NAMESIZE);
  451         else
  452                 uc->external = cfg->external;
  453         uc->plen = cfg->plen;
  454         uc->flags = cfg->flags & NPTV6_FLAGSMASK;
  455         uc->set = cfg->no.set;
  456         strlcpy(uc->name, cfg->no.name, sizeof(uc->name));
  457 }
  458 
  459 struct nptv6_dump_arg {
  460         struct ip_fw_chain *ch;
  461         struct sockopt_data *sd;
  462 };
  463 
  464 static int
  465 export_config_cb(struct namedobj_instance *ni, struct named_object *no,
  466     void *arg)
  467 {
  468         struct nptv6_dump_arg *da = (struct nptv6_dump_arg *)arg;
  469         ipfw_nptv6_cfg *uc;
  470 
  471         uc = (ipfw_nptv6_cfg *)ipfw_get_sopt_space(da->sd, sizeof(*uc));
  472         nptv6_export_config(da->ch, (struct nptv6_cfg *)no, uc);
  473         return (0);
  474 }
  475 
  476 static struct nptv6_cfg *
  477 nptv6_find(struct namedobj_instance *ni, const char *name, uint8_t set)
  478 {
  479         struct nptv6_cfg *cfg;
  480 
  481         cfg = (struct nptv6_cfg *)ipfw_objhash_lookup_name_type(ni, set,
  482             IPFW_TLV_NPTV6_NAME, name);
  483 
  484         return (cfg);
  485 }
  486 
  487 static void
  488 nptv6_calculate_adjustment(struct nptv6_cfg *cfg)
  489 {
  490         uint16_t i, e;
  491         uint16_t *p;
  492 
  493         /* Calculate checksum of internal prefix */
  494         for (i = 0, p = (uint16_t *)&cfg->internal;
  495             p < (uint16_t *)(&cfg->internal + 1); p++)
  496                 i = cksum_add(i, *p);
  497 
  498         /* Calculate checksum of external prefix */
  499         for (e = 0, p = (uint16_t *)&cfg->external;
  500             p < (uint16_t *)(&cfg->external + 1); p++)
  501                 e = cksum_add(e, *p);
  502 
  503         /* Adjustment value for Int->Ext direction */
  504         cfg->adjustment = cksum_add(~e, i);
  505 }
  506 
  507 static int
  508 nptv6_check_prefix(const struct in6_addr *addr)
  509 {
  510 
  511         if (IN6_IS_ADDR_MULTICAST(addr) ||
  512             IN6_IS_ADDR_LINKLOCAL(addr) ||
  513             IN6_IS_ADDR_LOOPBACK(addr) ||
  514             IN6_IS_ADDR_UNSPECIFIED(addr))
  515                 return (EINVAL);
  516         return (0);
  517 }
  518 
  519 static void
  520 nptv6_set_external(struct nptv6_cfg *cfg, struct in6_addr *addr)
  521 {
  522 
  523         cfg->external = *addr;
  524         IN6_MASK_ADDR(&cfg->external, &cfg->mask);
  525         nptv6_calculate_adjustment(cfg);
  526         cfg->flags |= NPTV6_READY;
  527 }
  528 
  529 /*
  530  * Try to determine what prefix to use as external for
  531  * configured interface name.
  532  */
  533 static void
  534 nptv6_find_prefix(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
  535     struct ifnet *ifp)
  536 {
  537         struct epoch_tracker et;
  538         struct ifaddr *ifa;
  539         struct in6_ifaddr *ia;
  540 
  541         MPASS(cfg->flags & NPTV6_DYNAMIC_PREFIX);
  542         IPFW_UH_WLOCK_ASSERT(ch);
  543 
  544         if (ifp == NULL) {
  545                 ifp = ifunit_ref(cfg->if_name);
  546                 if (ifp == NULL)
  547                         return;
  548         }
  549         NET_EPOCH_ENTER(et);
  550         CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  551                 if (ifa->ifa_addr->sa_family != AF_INET6)
  552                         continue;
  553                 ia = (struct in6_ifaddr *)ifa;
  554                 if (nptv6_check_prefix(&ia->ia_addr.sin6_addr) ||
  555                     IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
  556                     &cfg->internal, &cfg->mask))
  557                         continue;
  558                 /* Suitable address is found. */
  559                 nptv6_set_external(cfg, &ia->ia_addr.sin6_addr);
  560                 break;
  561         }
  562         NET_EPOCH_EXIT(et);
  563         if_rele(ifp);
  564 }
  565 
  566 struct ifaddr_event_args {
  567         struct ifnet *ifp;
  568         const struct in6_addr *addr;
  569         int event;
  570 };
  571 
  572 static int
  573 ifaddr_cb(struct namedobj_instance *ni, struct named_object *no,
  574     void *arg)
  575 {
  576         struct ifaddr_event_args *args;
  577         struct ip_fw_chain *ch;
  578         struct nptv6_cfg *cfg;
  579 
  580         ch = &V_layer3_chain;
  581         cfg = (struct nptv6_cfg *)SRV_OBJECT(ch, no->kidx);
  582         if ((cfg->flags & NPTV6_DYNAMIC_PREFIX) == 0)
  583                 return (0);
  584 
  585         args = arg;
  586         /* If interface name doesn't match, ignore */
  587         if (strncmp(args->ifp->if_xname, cfg->if_name, IF_NAMESIZE))
  588                 return (0);
  589         if (args->ifp->if_flags & IFF_DYING) { /* XXX: is it possible? */
  590                 cfg->flags &= ~NPTV6_READY;
  591                 return (0);
  592         }
  593         if (args->event == IFADDR_EVENT_DEL) {
  594                 /* If instance is not ready, ignore */
  595                 if ((cfg->flags & NPTV6_READY) == 0)
  596                         return (0);
  597                 /* If address does not match the external prefix, ignore */
  598                 if (IN6_ARE_MASKED_ADDR_EQUAL(&cfg->external, args->addr,
  599                     &cfg->mask) != 0)
  600                         return (0);
  601                 /* Otherwise clear READY flag */
  602                 cfg->flags &= ~NPTV6_READY;
  603         } else {/* IFADDR_EVENT_ADD */
  604                 /* If instance is already ready, ignore */
  605                 if (cfg->flags & NPTV6_READY)
  606                         return (0);
  607                 /* If address is not suitable for prefix, ignore */
  608                 if (nptv6_check_prefix(args->addr) ||
  609                     IN6_ARE_MASKED_ADDR_EQUAL(args->addr, &cfg->internal,
  610                     &cfg->mask))
  611                         return (0);
  612                 /* FALLTHROUGH */
  613         }
  614         MPASS(!(cfg->flags & NPTV6_READY));
  615         /* Try to determine the prefix */
  616         if_ref(args->ifp);
  617         nptv6_find_prefix(ch, cfg, args->ifp);
  618         return (0);
  619 }
  620 
  621 static void
  622 nptv6_ifaddrevent_handler(void *arg __unused, struct ifnet *ifp,
  623     struct ifaddr *ifa, int event)
  624 {
  625         struct ifaddr_event_args args;
  626         struct ip_fw_chain *ch;
  627 
  628         if (ifa->ifa_addr->sa_family != AF_INET6)
  629                 return;
  630 
  631         args.ifp = ifp;
  632         args.addr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
  633         args.event = event;
  634 
  635         ch = &V_layer3_chain;
  636         IPFW_UH_WLOCK(ch);
  637         ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), ifaddr_cb, &args,
  638             IPFW_TLV_NPTV6_NAME);
  639         IPFW_UH_WUNLOCK(ch);
  640 }
  641 
  642 /*
  643  * Creates new NPTv6 instance.
  644  * Data layout (v0)(current):
  645  * Request: [ ipfw_obj_lheader ipfw_nptv6_cfg ]
  646  *
  647  * Returns 0 on success
  648  */
  649 static int
  650 nptv6_create(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
  651     struct sockopt_data *sd)
  652 {
  653         struct in6_addr mask;
  654         ipfw_obj_lheader *olh;
  655         ipfw_nptv6_cfg *uc;
  656         struct namedobj_instance *ni;
  657         struct nptv6_cfg *cfg;
  658 
  659         if (sd->valsize != sizeof(*olh) + sizeof(*uc))
  660                 return (EINVAL);
  661 
  662         olh = (ipfw_obj_lheader *)sd->kbuf;
  663         uc = (ipfw_nptv6_cfg *)(olh + 1);
  664         if (ipfw_check_object_name_generic(uc->name) != 0)
  665                 return (EINVAL);
  666         if (uc->plen < 8 || uc->plen > 64 || uc->set >= IPFW_MAX_SETS)
  667                 return (EINVAL);
  668         if (nptv6_check_prefix(&uc->internal))
  669                 return (EINVAL);
  670         in6_prefixlen2mask(&mask, uc->plen);
  671         if ((uc->flags & NPTV6_DYNAMIC_PREFIX) == 0 && (
  672             nptv6_check_prefix(&uc->external) ||
  673             IN6_ARE_MASKED_ADDR_EQUAL(&uc->external, &uc->internal, &mask)))
  674                 return (EINVAL);
  675 
  676         ni = CHAIN_TO_SRV(ch);
  677         IPFW_UH_RLOCK(ch);
  678         if (nptv6_find(ni, uc->name, uc->set) != NULL) {
  679                 IPFW_UH_RUNLOCK(ch);
  680                 return (EEXIST);
  681         }
  682         IPFW_UH_RUNLOCK(ch);
  683 
  684         cfg = nptv6_alloc_config(uc->name, uc->set);
  685         cfg->plen = uc->plen;
  686         cfg->flags = uc->flags & NPTV6_FLAGSMASK;
  687         if (cfg->plen <= 48)
  688                 cfg->flags |= NPTV6_48PLEN;
  689         cfg->mask = mask;
  690         cfg->internal = uc->internal;
  691         IN6_MASK_ADDR(&cfg->internal, &mask);
  692         if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
  693                 memcpy(cfg->if_name, uc->if_name, IF_NAMESIZE);
  694         else
  695                 nptv6_set_external(cfg, &uc->external);
  696 
  697         if ((uc->flags & NPTV6_DYNAMIC_PREFIX) != 0 &&
  698             nptv6_ifaddr_event == NULL)
  699                 nptv6_ifaddr_event = EVENTHANDLER_REGISTER(
  700                     ifaddr_event_ext, nptv6_ifaddrevent_handler, NULL,
  701                     EVENTHANDLER_PRI_ANY);
  702 
  703         IPFW_UH_WLOCK(ch);
  704         if (ipfw_objhash_alloc_idx(ni, &cfg->no.kidx) != 0) {
  705                 IPFW_UH_WUNLOCK(ch);
  706                 nptv6_free_config(cfg);
  707                 return (ENOSPC);
  708         }
  709         ipfw_objhash_add(ni, &cfg->no);
  710         SRV_OBJECT(ch, cfg->no.kidx) = cfg;
  711         if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
  712                 nptv6_find_prefix(ch, cfg, NULL);
  713         IPFW_UH_WUNLOCK(ch);
  714 
  715         return (0);
  716 }
  717 
  718 /*
  719  * Destroys NPTv6 instance.
  720  * Data layout (v0)(current):
  721  * Request: [ ipfw_obj_header ]
  722  *
  723  * Returns 0 on success
  724  */
  725 static int
  726 nptv6_destroy(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
  727     struct sockopt_data *sd)
  728 {
  729         ipfw_obj_header *oh;
  730         struct nptv6_cfg *cfg;
  731 
  732         if (sd->valsize != sizeof(*oh))
  733                 return (EINVAL);
  734 
  735         oh = (ipfw_obj_header *)sd->kbuf;
  736         if (ipfw_check_object_name_generic(oh->ntlv.name) != 0)
  737                 return (EINVAL);
  738 
  739         IPFW_UH_WLOCK(ch);
  740         cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
  741         if (cfg == NULL) {
  742                 IPFW_UH_WUNLOCK(ch);
  743                 return (ESRCH);
  744         }
  745         if (cfg->no.refcnt > 0) {
  746                 IPFW_UH_WUNLOCK(ch);
  747                 return (EBUSY);
  748         }
  749 
  750         ipfw_reset_eaction_instance(ch, V_nptv6_eid, cfg->no.kidx);
  751         SRV_OBJECT(ch, cfg->no.kidx) = NULL;
  752         ipfw_objhash_del(CHAIN_TO_SRV(ch), &cfg->no);
  753         ipfw_objhash_free_idx(CHAIN_TO_SRV(ch), cfg->no.kidx);
  754         IPFW_UH_WUNLOCK(ch);
  755 
  756         nptv6_free_config(cfg);
  757         return (0);
  758 }
  759 
  760 /*
  761  * Get or change nptv6 instance config.
  762  * Request: [ ipfw_obj_header [ ipfw_nptv6_cfg ] ]
  763  */
  764 static int
  765 nptv6_config(struct ip_fw_chain *chain, ip_fw3_opheader *op,
  766     struct sockopt_data *sd)
  767 {
  768 
  769         return (EOPNOTSUPP);
  770 }
  771 
  772 /*
  773  * Lists all NPTv6 instances currently available in kernel.
  774  * Data layout (v0)(current):
  775  * Request: [ ipfw_obj_lheader ]
  776  * Reply: [ ipfw_obj_lheader ipfw_nptv6_cfg x N ]
  777  *
  778  * Returns 0 on success
  779  */
  780 static int
  781 nptv6_list(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
  782     struct sockopt_data *sd)
  783 {
  784         ipfw_obj_lheader *olh;
  785         struct nptv6_dump_arg da;
  786 
  787         /* Check minimum header size */
  788         if (sd->valsize < sizeof(ipfw_obj_lheader))
  789                 return (EINVAL);
  790 
  791         olh = (ipfw_obj_lheader *)ipfw_get_sopt_header(sd, sizeof(*olh));
  792 
  793         IPFW_UH_RLOCK(ch);
  794         olh->count = ipfw_objhash_count_type(CHAIN_TO_SRV(ch),
  795             IPFW_TLV_NPTV6_NAME);
  796         olh->objsize = sizeof(ipfw_nptv6_cfg);
  797         olh->size = sizeof(*olh) + olh->count * olh->objsize;
  798 
  799         if (sd->valsize < olh->size) {
  800                 IPFW_UH_RUNLOCK(ch);
  801                 return (ENOMEM);
  802         }
  803         memset(&da, 0, sizeof(da));
  804         da.ch = ch;
  805         da.sd = sd;
  806         ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), export_config_cb,
  807             &da, IPFW_TLV_NPTV6_NAME);
  808         IPFW_UH_RUNLOCK(ch);
  809 
  810         return (0);
  811 }
  812 
  813 #define __COPY_STAT_FIELD(_cfg, _stats, _field) \
  814         (_stats)->_field = NPTV6STAT_FETCH(_cfg, _field)
  815 static void
  816 export_stats(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
  817     struct ipfw_nptv6_stats *stats)
  818 {
  819 
  820         __COPY_STAT_FIELD(cfg, stats, in2ex);
  821         __COPY_STAT_FIELD(cfg, stats, ex2in);
  822         __COPY_STAT_FIELD(cfg, stats, dropped);
  823 }
  824 
  825 /*
  826  * Get NPTv6 statistics.
  827  * Data layout (v0)(current):
  828  * Request: [ ipfw_obj_header ]
  829  * Reply: [ ipfw_obj_header ipfw_obj_ctlv [ uint64_t x N ]]
  830  *
  831  * Returns 0 on success
  832  */
  833 static int
  834 nptv6_stats(struct ip_fw_chain *ch, ip_fw3_opheader *op,
  835     struct sockopt_data *sd)
  836 {
  837         struct ipfw_nptv6_stats stats;
  838         struct nptv6_cfg *cfg;
  839         ipfw_obj_header *oh;
  840         ipfw_obj_ctlv *ctlv;
  841         size_t sz;
  842 
  843         sz = sizeof(ipfw_obj_header) + sizeof(ipfw_obj_ctlv) + sizeof(stats);
  844         if (sd->valsize % sizeof(uint64_t))
  845                 return (EINVAL);
  846         if (sd->valsize < sz)
  847                 return (ENOMEM);
  848         oh = (ipfw_obj_header *)ipfw_get_sopt_header(sd, sz);
  849         if (oh == NULL)
  850                 return (EINVAL);
  851         if (ipfw_check_object_name_generic(oh->ntlv.name) != 0 ||
  852             oh->ntlv.set >= IPFW_MAX_SETS)
  853                 return (EINVAL);
  854         memset(&stats, 0, sizeof(stats));
  855 
  856         IPFW_UH_RLOCK(ch);
  857         cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
  858         if (cfg == NULL) {
  859                 IPFW_UH_RUNLOCK(ch);
  860                 return (ESRCH);
  861         }
  862         export_stats(ch, cfg, &stats);
  863         IPFW_UH_RUNLOCK(ch);
  864 
  865         ctlv = (ipfw_obj_ctlv *)(oh + 1);
  866         memset(ctlv, 0, sizeof(*ctlv));
  867         ctlv->head.type = IPFW_TLV_COUNTERS;
  868         ctlv->head.length = sz - sizeof(ipfw_obj_header);
  869         ctlv->count = sizeof(stats) / sizeof(uint64_t);
  870         ctlv->objsize = sizeof(uint64_t);
  871         ctlv->version = 1;
  872         memcpy(ctlv + 1, &stats, sizeof(stats));
  873         return (0);
  874 }
  875 
  876 /*
  877  * Reset NPTv6 statistics.
  878  * Data layout (v0)(current):
  879  * Request: [ ipfw_obj_header ]
  880  *
  881  * Returns 0 on success
  882  */
  883 static int
  884 nptv6_reset_stats(struct ip_fw_chain *ch, ip_fw3_opheader *op,
  885     struct sockopt_data *sd)
  886 {
  887         struct nptv6_cfg *cfg;
  888         ipfw_obj_header *oh;
  889 
  890         if (sd->valsize != sizeof(*oh))
  891                 return (EINVAL);
  892         oh = (ipfw_obj_header *)sd->kbuf;
  893         if (ipfw_check_object_name_generic(oh->ntlv.name) != 0 ||
  894             oh->ntlv.set >= IPFW_MAX_SETS)
  895                 return (EINVAL);
  896 
  897         IPFW_UH_WLOCK(ch);
  898         cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
  899         if (cfg == NULL) {
  900                 IPFW_UH_WUNLOCK(ch);
  901                 return (ESRCH);
  902         }
  903         COUNTER_ARRAY_ZERO(cfg->stats, NPTV6STATS);
  904         IPFW_UH_WUNLOCK(ch);
  905         return (0);
  906 }
  907 
  908 static struct ipfw_sopt_handler scodes[] = {
  909         { IP_FW_NPTV6_CREATE, 0,        HDIR_SET,       nptv6_create },
  910         { IP_FW_NPTV6_DESTROY,0,        HDIR_SET,       nptv6_destroy },
  911         { IP_FW_NPTV6_CONFIG, 0,        HDIR_BOTH,      nptv6_config },
  912         { IP_FW_NPTV6_LIST,   0,        HDIR_GET,       nptv6_list },
  913         { IP_FW_NPTV6_STATS,  0,        HDIR_GET,       nptv6_stats },
  914         { IP_FW_NPTV6_RESET_STATS,0,    HDIR_SET,       nptv6_reset_stats },
  915 };
  916 
  917 static int
  918 nptv6_classify(ipfw_insn *cmd, uint16_t *puidx, uint8_t *ptype)
  919 {
  920         ipfw_insn *icmd;
  921 
  922         icmd = cmd - 1;
  923         NPTV6_DEBUG("opcode %d, arg1 %d, opcode0 %d, arg1 %d",
  924             cmd->opcode, cmd->arg1, icmd->opcode, icmd->arg1);
  925         if (icmd->opcode != O_EXTERNAL_ACTION ||
  926             icmd->arg1 != V_nptv6_eid)
  927                 return (1);
  928 
  929         *puidx = cmd->arg1;
  930         *ptype = 0;
  931         return (0);
  932 }
  933 
  934 static void
  935 nptv6_update_arg1(ipfw_insn *cmd, uint16_t idx)
  936 {
  937 
  938         cmd->arg1 = idx;
  939         NPTV6_DEBUG("opcode %d, arg1 -> %d", cmd->opcode, cmd->arg1);
  940 }
  941 
  942 static int
  943 nptv6_findbyname(struct ip_fw_chain *ch, struct tid_info *ti,
  944     struct named_object **pno)
  945 {
  946         int err;
  947 
  948         err = ipfw_objhash_find_type(CHAIN_TO_SRV(ch), ti,
  949             IPFW_TLV_NPTV6_NAME, pno);
  950         NPTV6_DEBUG("uidx %u, type %u, err %d", ti->uidx, ti->type, err);
  951         return (err);
  952 }
  953 
  954 static struct named_object *
  955 nptv6_findbykidx(struct ip_fw_chain *ch, uint16_t idx)
  956 {
  957         struct namedobj_instance *ni;
  958         struct named_object *no;
  959 
  960         IPFW_UH_WLOCK_ASSERT(ch);
  961         ni = CHAIN_TO_SRV(ch);
  962         no = ipfw_objhash_lookup_kidx(ni, idx);
  963         KASSERT(no != NULL, ("NPT with index %d not found", idx));
  964 
  965         NPTV6_DEBUG("kidx %u -> %s", idx, no->name);
  966         return (no);
  967 }
  968 
  969 static int
  970 nptv6_manage_sets(struct ip_fw_chain *ch, uint16_t set, uint8_t new_set,
  971     enum ipfw_sets_cmd cmd)
  972 {
  973 
  974         return (ipfw_obj_manage_sets(CHAIN_TO_SRV(ch), IPFW_TLV_NPTV6_NAME,
  975             set, new_set, cmd));
  976 }
  977 
  978 static struct opcode_obj_rewrite opcodes[] = {
  979         {
  980                 .opcode = O_EXTERNAL_INSTANCE,
  981                 .etlv = IPFW_TLV_EACTION /* just show it isn't table */,
  982                 .classifier = nptv6_classify,
  983                 .update = nptv6_update_arg1,
  984                 .find_byname = nptv6_findbyname,
  985                 .find_bykidx = nptv6_findbykidx,
  986                 .manage_sets = nptv6_manage_sets,
  987         },
  988 };
  989 
  990 static int
  991 destroy_config_cb(struct namedobj_instance *ni, struct named_object *no,
  992     void *arg)
  993 {
  994         struct nptv6_cfg *cfg;
  995         struct ip_fw_chain *ch;
  996 
  997         ch = (struct ip_fw_chain *)arg;
  998         IPFW_UH_WLOCK_ASSERT(ch);
  999 
 1000         cfg = (struct nptv6_cfg *)SRV_OBJECT(ch, no->kidx);
 1001         SRV_OBJECT(ch, no->kidx) = NULL;
 1002         ipfw_objhash_del(ni, &cfg->no);
 1003         ipfw_objhash_free_idx(ni, cfg->no.kidx);
 1004         nptv6_free_config(cfg);
 1005         return (0);
 1006 }
 1007 
 1008 int
 1009 nptv6_init(struct ip_fw_chain *ch, int first)
 1010 {
 1011 
 1012         V_nptv6_eid = ipfw_add_eaction(ch, ipfw_nptv6, "nptv6");
 1013         if (V_nptv6_eid == 0)
 1014                 return (ENXIO);
 1015         IPFW_ADD_SOPT_HANDLER(first, scodes);
 1016         IPFW_ADD_OBJ_REWRITER(first, opcodes);
 1017         return (0);
 1018 }
 1019 
 1020 void
 1021 nptv6_uninit(struct ip_fw_chain *ch, int last)
 1022 {
 1023 
 1024         if (last && nptv6_ifaddr_event != NULL)
 1025                 EVENTHANDLER_DEREGISTER(ifaddr_event_ext, nptv6_ifaddr_event);
 1026         IPFW_DEL_OBJ_REWRITER(last, opcodes);
 1027         IPFW_DEL_SOPT_HANDLER(last, scodes);
 1028         ipfw_del_eaction(ch, V_nptv6_eid);
 1029         /*
 1030          * Since we already have deregistered external action,
 1031          * our named objects become unaccessible via rules, because
 1032          * all rules were truncated by ipfw_del_eaction().
 1033          * So, we can unlink and destroy our named objects without holding
 1034          * IPFW_WLOCK().
 1035          */
 1036         IPFW_UH_WLOCK(ch);
 1037         ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), destroy_config_cb, ch,
 1038             IPFW_TLV_NPTV6_NAME);
 1039         V_nptv6_eid = 0;
 1040         IPFW_UH_WUNLOCK(ch);
 1041 }

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