sys/netinet/ip_divert.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $
  30  */
  31
  32 #define _IP_VHL
  33
  34 #include "opt_inet.h"
  35 #include "opt_ipdivert.h"
  36
  37 #ifndef INET
  38 #error "IPDIVERT requires INET."
  39 #endif
  40
  41 #include <sys/param.h>
  42 #include <sys/kernel.h>
  43 #include <sys/malloc.h>
  44 #include <sys/mbuf.h>
  45 #include <sys/socket.h>
  46 #include <sys/protosw.h>
  47 #include <sys/socketvar.h>
  48 #include <sys/socketvar2.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/systm.h>
  51 #include <sys/proc.h>
  52 #include <sys/priv.h>
  53 #include <sys/in_cksum.h>
  54 #include <sys/lock.h>
  55 #include <sys/msgport.h>
  56
  57 #include <net/if.h>
  58 #include <net/route.h>
  59
  60 #include <net/netmsg2.h>
  61 #include <net/netisr2.h>
  62 #include <sys/thread2.h>
  63 #include <sys/mplock2.h>
  64
  65 #include <netinet/in.h>
  66 #include <netinet/in_systm.h>
  67 #include <netinet/ip.h>
  68 #include <netinet/in_pcb.h>
  69 #include <netinet/in_var.h>
  70 #include <netinet/ip_var.h>
  71 #include <netinet/ip_divert.h>
  72
  73 /*
  74  * Divert sockets
  75  */
  76
  77 /*
  78  * Allocate enough space to hold a full IP packet
  79  */
  80 #define DIVSNDQ         (65536 + 100)
  81 #define DIVRCVQ         (65536 + 100)
  82
  83 #define DIV_IS_OUTPUT(sin)      ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
  84
  85 #define DIV_OUTPUT      0x10000
  86 #define DIV_INPUT       0x20000
  87
  88 /*
  89  * Divert sockets work in conjunction with ipfw, see the divert(4)
  90  * manpage for features.
  91  * Internally, packets selected by ipfw in ip_input() or ip_output(),
  92  * and never diverted before, are passed to the input queue of the
  93  * divert socket with a given 'divert_port' number (as specified in
  94  * the matching ipfw rule), and they are tagged with a 16 bit cookie
  95  * (representing the rule number of the matching ipfw rule), which
  96  * is passed to process reading from the socket.
  97  *
  98  * Packets written to the divert socket are again tagged with a cookie
  99  * (usually the same as above) and a destination address.
 100  * If the destination address is INADDR_ANY then the packet is
 101  * treated as outgoing and sent to ip_output(), otherwise it is
 102  * treated as incoming and sent to ip_input().
 103  * In both cases, the packet is tagged with the cookie.
 104  *
 105  * On reinjection, processing in ip_input() and ip_output()
 106  * will be exactly the same as for the original packet, except that
 107  * ipfw processing will start at the rule number after the one
 108  * written in the cookie (so, tagging a packet with a cookie of 0
 109  * will cause it to be effectively considered as a standard packet).
 110  */
 111
 112 /* Internal variables */
 113 static struct inpcbinfo divcbinfo;
 114 static struct inpcbportinfo divcbportinfo;
 115
 116 static u_long   div_sendspace = DIVSNDQ;        /* XXX sysctl ? */
 117 static u_long   div_recvspace = DIVRCVQ;        /* XXX sysctl ? */
 118
 119 static struct mbuf *ip_divert(struct mbuf *, int, int);
 120
 121 /*
 122  * Initialize divert connection block queue.
 123  */
 124 void
 125 div_init(void)
 126 {
 127         in_pcbinfo_init(&divcbinfo, 0, FALSE);
 128         in_pcbportinfo_init(&divcbportinfo, 1, 0);
 129         /*
 130          * XXX We don't use the hash list for divert IP, but it's easier
 131          * to allocate a one entry hash list than it is to check all
 132          * over the place for hashbase == NULL.
 133          */
 134         divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
 135         in_pcbportinfo_set(&divcbinfo, &divcbportinfo, 1);
 136         divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
 137                                               &divcbinfo.wildcardhashmask);
 138         divcbinfo.ipi_size = sizeof(struct inpcb);
 139         ip_divert_p = ip_divert;
 140 }
 141
 142 /*
 143  * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
 144  * with that protocol number to enter the system from the outside.
 145  */
 146 int
 147 div_input(struct mbuf **mp, int *offp, int proto)
 148 {
 149         struct mbuf *m = *mp;
 150
 151         ipstat.ips_noproto++;
 152         m_freem(m);
 153         return(IPPROTO_DONE);
 154 }
 155
 156 /*
 157  * Divert a packet by passing it up to the divert socket at port 'port'.
 158  *
 159  * Setup generic address and protocol structures for div_input routine,
 160  * then pass them along with mbuf chain.
 161  */
 162 static void
 163 div_packet(struct mbuf *m, int incoming, int port)
 164 {
 165         struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
 166         struct inpcb *inp;
 167         struct socket *sa;
 168         struct m_tag *mtag;
 169         struct divert_info *divinfo;
 170         u_int16_t nport;
 171
 172         ASSERT_NETISR0;
 173
 174         /* Locate the divert info */
 175         mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
 176         divinfo = m_tag_data(mtag);
 177         divsrc.sin_port = divinfo->skipto;
 178
 179         /*
 180          * Record receive interface address, if any.
 181          * But only for incoming packets.
 182          */
 183         divsrc.sin_addr.s_addr = 0;
 184         if (incoming) {
 185                 struct ifaddr_container *ifac;
 186
 187                 /* Find IP address for receive interface */
 188                 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
 189                               ifa_link) {
 190                         struct ifaddr *ifa = ifac->ifa;
 191
 192                         if (ifa->ifa_addr == NULL)
 193                                 continue;
 194                         if (ifa->ifa_addr->sa_family != AF_INET)
 195                                 continue;
 196                         divsrc.sin_addr =
 197                             ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
 198                         break;
 199                 }
 200         }
 201         /*
 202          * Record the incoming interface name whenever we have one.
 203          */
 204         if (m->m_pkthdr.rcvif) {
 205                 /*
 206                  * Hide the actual interface name in there in the
 207                  * sin_zero array. XXX This needs to be moved to a
 208                  * different sockaddr type for divert, e.g.
 209                  * sockaddr_div with multiple fields like
 210                  * sockaddr_dl. Presently we have only 7 bytes
 211                  * but that will do for now as most interfaces
 212                  * are 4 or less + 2 or less bytes for unit.
 213                  * There is probably a faster way of doing this,
 214                  * possibly taking it from the sockaddr_dl on the iface.
 215                  * This solves the problem of a P2P link and a LAN interface
 216                  * having the same address, which can result in the wrong
 217                  * interface being assigned to the packet when fed back
 218                  * into the divert socket. Theoretically if the daemon saves
 219                  * and re-uses the sockaddr_in as suggested in the man pages,
 220                  * this iface name will come along for the ride.
 221                  * (see div_output for the other half of this.)
 222                  */
 223                 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s",
 224                           m->m_pkthdr.rcvif->if_xname);
 225         }
 226
 227         /* Put packet on socket queue, if any */
 228         sa = NULL;
 229         nport = htons((u_int16_t)port);
 230
 231         /*
 232          * Following loop to locate the inpcb is MPSAFE since the inpcb
 233          * insertion/removal happens on the same CPU (CPU0).
 234          */
 235         LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
 236                 if (inp->inp_flags & INP_PLACEMARKER)
 237                         continue;
 238                 if (inp->inp_lport == nport)
 239                         sa = inp->inp_socket;
 240         }
 241         if (sa) {
 242                 lwkt_gettoken(&sa->so_rcv.ssb_token);
 243                 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
 244                         m_freem(m);
 245                 else
 246                         sorwakeup(sa);
 247                 lwkt_reltoken(&sa->so_rcv.ssb_token);
 248         } else {
 249                 m_freem(m);
 250                 ipstat.ips_noproto++;
 251                 ipstat.ips_delivered--;
 252         }
 253 }
 254
 255 static void
 256 div_packet_handler(netmsg_t msg)
 257 {
 258         struct mbuf *m;
 259         int port, incoming = 0;
 260
 261         m = msg->packet.nm_packet;
 262
 263         port = msg->lmsg.u.ms_result32 & 0xffff;
 264         if (msg->lmsg.u.ms_result32 & DIV_INPUT)
 265                 incoming = 1;
 266         div_packet(m, incoming, port);
 267         /* no reply, msg embedded in mbuf */
 268 }
 269
 270 static void
 271 divert_packet(struct mbuf *m, int incoming)
 272 {
 273         struct m_tag *mtag;
 274         struct divert_info *divinfo;
 275         int port;
 276
 277         M_ASSERTPKTHDR(m);
 278
 279         /* Assure header */
 280         if (m->m_len < sizeof(struct ip) &&
 281             (m = m_pullup(m, sizeof(struct ip))) == NULL)
 282                 return;
 283
 284         mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
 285         KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
 286         divinfo = m_tag_data(mtag);
 287
 288         port = divinfo->port;
 289         KASSERT(port != 0, ("%s: port=0", __func__));
 290
 291         if (mycpuid != 0) {
 292                 struct netmsg_packet *nmp;
 293
 294                 nmp = &m->m_hdr.mh_netmsg;
 295                 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
 296                             0, div_packet_handler);
 297                 nmp->nm_packet = m;
 298
 299                 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
 300                 if (incoming)
 301                         nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
 302                 else
 303                         nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
 304
 305                 lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg);
 306         } else {
 307                 div_packet(m, incoming, port);
 308         }
 309 }
 310
 311 /*
 312  * Deliver packet back into the IP processing machinery.
 313  *
 314  * If no address specified, or address is 0.0.0.0, send to ip_output();
 315  * otherwise, send to ip_input() and mark as having been received on
 316  * the interface with that address.
 317  */
 318 static int
 319 div_output(struct socket *so, struct mbuf *m,
 320         struct sockaddr_in *sin, struct mbuf *control)
 321 {
 322         int error = 0;
 323         struct m_tag *mtag;
 324         struct divert_info *divinfo;
 325
 326         ASSERT_NETISR0;
 327
 328         if (control)
 329                 m_freem(control);               /* XXX */
 330
 331         /*
 332          * Prepare the tag for divert info. Note that a packet
 333          * with a 0 tag in mh_data is effectively untagged,
 334          * so we could optimize that case.
 335          */
 336         mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), M_NOWAIT);
 337         if (mtag == NULL) {
 338                 error = ENOBUFS;
 339                 goto cantsend;
 340         }
 341         m_tag_prepend(m, mtag);
 342
 343         /* Loopback avoidance and state recovery */
 344         divinfo = m_tag_data(mtag);
 345         if (sin)
 346                 divinfo->skipto = sin->sin_port;
 347         else
 348                 divinfo->skipto = 0;
 349
 350         /* Reinject packet into the system as incoming or outgoing */
 351         if (DIV_IS_OUTPUT(sin)) {
 352                 struct ip *const ip = mtod(m, struct ip *);
 353
 354                 /* Don't allow packet length sizes that will crash */
 355                 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
 356                         error = EINVAL;
 357                         goto cantsend;
 358                 }
 359
 360                 /* Convert fields to host order for ip_output() */
 361                 ip->ip_len = ntohs(ip->ip_len);
 362                 ip->ip_off = ntohs(ip->ip_off);
 363
 364                 /* Send packet to output processing */
 365                 ipstat.ips_rawout++;                    /* XXX */
 366                 error = ip_output(m, NULL, NULL,
 367                             (so->so_options & SO_DONTROUTE) |
 368                             IP_ALLOWBROADCAST | IP_RAWOUTPUT,
 369                             NULL, NULL);
 370         } else {
 371                 ip_input(m);
 372         }
 373         return error;
 374
 375 cantsend:
 376         m_freem(m);
 377         return error;
 378 }
 379
 380 static void
 381 div_attach(netmsg_t msg)
 382 {
 383         struct socket *so = msg->attach.base.nm_so;
 384         int proto = msg->attach.nm_proto;
 385         struct pru_attach_info *ai = msg->attach.nm_ai;
 386         struct inpcb *inp;
 387         int error;
 388
 389         ASSERT_NETISR0;
 390
 391         inp  = so->so_pcb;
 392         if (inp)
 393                 panic("div_attach");
 394         error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
 395         if (error)
 396                 goto out;
 397
 398         error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
 399         if (error)
 400                 goto out;
 401         error = in_pcballoc(so, &divcbinfo);
 402         if (error)
 403                 goto out;
 404         inp = (struct inpcb *)so->so_pcb;
 405         inp->inp_ip_p = proto;
 406         inp->inp_flags |= INP_HDRINCL;
 407         /*
 408          * The socket is always "connected" because
 409          * we always know "where" to send the packet.
 410          */
 411         sosetstate(so, SS_ISCONNECTED);
 412         error = 0;
 413 out:
 414         lwkt_replymsg(&msg->attach.base.lmsg, error);
 415 }
 416
 417 static void
 418 div_detach(netmsg_t msg)
 419 {
 420         struct socket *so = msg->detach.base.nm_so;
 421         struct inpcb *inp;
 422
 423         ASSERT_NETISR0;
 424
 425         inp = so->so_pcb;
 426         if (inp == NULL)
 427                 panic("div_detach");
 428         in_pcbdetach(inp);
 429         lwkt_replymsg(&msg->detach.base.lmsg, 0);
 430 }
 431
 432 static void
 433 div_abort(netmsg_t msg)
 434 {
 435         /*
 436          * Divert socket does not support listen(2),
 437          * so this should never be called.
 438          */
 439         panic("div_abort is called");
 440 }
 441
 442 static void
 443 div_disconnect(netmsg_t msg)
 444 {
 445         struct socket *so = msg->disconnect.base.nm_so;
 446         int error;
 447
 448         ASSERT_NETISR0;
 449
 450         if (so->so_state & SS_ISCONNECTED) {
 451                 soisdisconnected(so);
 452                 error = 0;
 453         } else {
 454                 error = ENOTCONN;
 455         }
 456         lwkt_replymsg(&msg->disconnect.base.lmsg, error);
 457 }
 458
 459 static void
 460 div_bind(netmsg_t msg)
 461 {
 462         struct socket *so = msg->bind.base.nm_so;
 463         struct sockaddr *nam = msg->bind.nm_nam;
 464         int error;
 465
 466         ASSERT_NETISR0;
 467
 468         /*
 469          * in_pcbbind assumes that nam is a sockaddr_in
 470          * and in_pcbbind requires a valid address. Since divert
 471          * sockets don't we need to make sure the address is
 472          * filled in properly.
 473          * XXX -- divert should not be abusing in_pcbind
 474          * and should probably have its own family.
 475          */
 476         if (nam->sa_family != AF_INET) {
 477                 error = EAFNOSUPPORT;
 478         } else {
 479                 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
 480                 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
 481         }
 482         lwkt_replymsg(&msg->bind.base.lmsg, error);
 483 }
 484
 485 static void
 486 div_shutdown(netmsg_t msg)
 487 {
 488         struct socket *so = msg->shutdown.base.nm_so;
 489
 490         ASSERT_NETISR0;
 491
 492         socantsendmore(so);
 493
 494         lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
 495 }
 496
 497 static void
 498 div_send(netmsg_t msg)
 499 {
 500         struct socket *so = msg->send.base.nm_so;
 501         struct mbuf *m = msg->send.nm_m;
 502         struct sockaddr *nam = msg->send.nm_addr;
 503         struct mbuf *control = msg->send.nm_control;
 504         int error;
 505
 506         /* Length check already done in ip_hashfn() */
 507         KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
 508
 509         /* Send packet */
 510         error = div_output(so, m, (struct sockaddr_in *)nam, control);
 511         lwkt_replymsg(&msg->send.base.lmsg, error);
 512 }
 513
 514 SYSCTL_DECL(_net_inet_divert);
 515 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 1,
 516             in_pcblist_range, "S,xinpcb", "List of active divert sockets");
 517
 518 struct pr_usrreqs div_usrreqs = {
 519         .pru_abort = div_abort,
 520         .pru_accept = pr_generic_notsupp,
 521         .pru_attach = div_attach,
 522         .pru_bind = div_bind,
 523         .pru_connect = pr_generic_notsupp,
 524         .pru_connect2 = pr_generic_notsupp,
 525         .pru_control = in_control_dispatch,
 526         .pru_detach = div_detach,
 527         .pru_disconnect = div_disconnect,
 528         .pru_listen = pr_generic_notsupp,
 529         .pru_peeraddr = in_setpeeraddr_dispatch,
 530         .pru_rcvd = pr_generic_notsupp,
 531         .pru_rcvoob = pr_generic_notsupp,
 532         .pru_send = div_send,
 533         .pru_sense = pru_sense_null,
 534         .pru_shutdown = div_shutdown,
 535         .pru_sockaddr = in_setsockaddr_dispatch,
 536         .pru_sosend = sosend,
 537         .pru_soreceive = soreceive
 538 };
 539
 540 static struct mbuf *
 541 ip_divert_out(struct mbuf *m, int tee)
 542 {
 543         struct mbuf *clone = NULL;
 544         struct ip *ip = mtod(m, struct ip *);
 545
 546         /* Clone packet if we're doing a 'tee' */
 547         if (tee)
 548                 clone = m_dup(m, M_NOWAIT);
 549
 550         /*
 551          * XXX
 552          * delayed checksums are not currently compatible
 553          * with divert sockets.
 554          */
 555         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 556                 in_delayed_cksum(m);
 557                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 558         }
 559
 560         /* Restore packet header fields to original values */
 561         ip->ip_len = htons(ip->ip_len);
 562         ip->ip_off = htons(ip->ip_off);
 563
 564         /* Deliver packet to divert input routine */
 565         divert_packet(m, 0);
 566
 567         /* If 'tee', continue with original packet */
 568         return clone;
 569 }
 570
 571 static struct mbuf *
 572 ip_divert_in(struct mbuf *m, int tee)
 573 {
 574         struct mbuf *clone = NULL;
 575         struct ip *ip = mtod(m, struct ip *);
 576         struct m_tag *mtag;
 577
 578         if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
 579                 const struct divert_info *divinfo;
 580                 u_short frag_off;
 581                 int hlen;
 582
 583                 /*
 584                  * Only trust divert info in the fragment
 585                  * at offset 0.
 586                  */
 587                 frag_off = ip->ip_off << 3;
 588                 if (frag_off != 0) {
 589                         mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
 590                         m_tag_delete(m, mtag);
 591                 }
 592
 593                 /*
 594                  * Attempt reassembly; if it succeeds, proceed.
 595                  * ip_reass() will return a different mbuf.
 596                  */
 597                 m = ip_reass(m);
 598                 if (m == NULL)
 599                         return NULL;
 600                 ip = mtod(m, struct ip *);
 601
 602                 /* Caller need to redispatch the packet, if it is for us */
 603                 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
 604
 605                 /*
 606                  * Get the header length of the reassembled
 607                  * packet
 608                  */
 609                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 610
 611                 /*
 612                  * Restore original checksum before diverting
 613                  * packet
 614                  */
 615                 ip->ip_len += hlen;
 616                 ip->ip_len = htons(ip->ip_len);
 617                 ip->ip_off = htons(ip->ip_off);
 618                 ip->ip_sum = 0;
 619                 if (hlen == sizeof(struct ip))
 620                         ip->ip_sum = in_cksum_hdr(ip);
 621                 else
 622                         ip->ip_sum = in_cksum(m, hlen);
 623                 ip->ip_off = ntohs(ip->ip_off);
 624                 ip->ip_len = ntohs(ip->ip_len);
 625
 626                 /*
 627                  * Only use the saved divert info
 628                  */
 629                 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
 630                 if (mtag == NULL) {
 631                         /* Wrongly configured ipfw */
 632                         kprintf("ip_input no divert info\n");
 633                         m_freem(m);
 634                         return NULL;
 635                 }
 636                 divinfo = m_tag_data(mtag);
 637                 tee = divinfo->tee;
 638         }
 639
 640         /*
 641          * Divert or tee packet to the divert protocol if
 642          * required.
 643          */
 644
 645         /* Clone packet if we're doing a 'tee' */
 646         if (tee)
 647                 clone = m_dup(m, M_NOWAIT);
 648
 649         /*
 650          * Restore packet header fields to original
 651          * values
 652          */
 653         ip->ip_len = htons(ip->ip_len);
 654         ip->ip_off = htons(ip->ip_off);
 655
 656         /* Deliver packet to divert input routine */
 657         divert_packet(m, 1);
 658
 659         /* Catch invalid reference */
 660         m = NULL;
 661         ip = NULL;
 662
 663         ipstat.ips_delivered++;
 664
 665         /* If 'tee', continue with original packet */
 666         if (clone != NULL) {
 667                 /*
 668                  * Complete processing of the packet.
 669                  * XXX Better safe than sorry, remove the DIVERT tag.
 670                  */
 671                 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
 672                 KKASSERT(mtag != NULL);
 673                 m_tag_delete(clone, mtag);
 674         }
 675         return clone;
 676 }
 677
 678 static struct mbuf *
 679 ip_divert(struct mbuf *m, int tee, int incoming)
 680 {
 681         struct mbuf *ret;
 682
 683         if (incoming)
 684                 ret = ip_divert_in(m, tee);
 685         else
 686                 ret = ip_divert_out(m, tee);
 687         return ret;
 688 }