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

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    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  * 4. 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: releng/6.0/sys/netinet/ip_divert.c 146182 2005-05-13 11:44:37Z glebius $
   30  */
   31 
   32 #if !defined(KLD_MODULE)
   33 #include "opt_inet.h"
   34 #include "opt_ipfw.h"
   35 #include "opt_mac.h"
   36 #ifndef INET
   37 #error "IPDIVERT requires INET."
   38 #endif
   39 #ifndef IPFIREWALL
   40 #error "IPDIVERT requires IPFIREWALL"
   41 #endif
   42 #endif
   43 
   44 #include <sys/param.h>
   45 #include <sys/kernel.h>
   46 #include <sys/lock.h>
   47 #include <sys/malloc.h>
   48 #include <sys/mac.h>
   49 #include <sys/mbuf.h>
   50 #include <sys/module.h>
   51 #include <sys/kernel.h>
   52 #include <sys/proc.h>
   53 #include <sys/protosw.h>
   54 #include <sys/signalvar.h>
   55 #include <sys/socket.h>
   56 #include <sys/socketvar.h>
   57 #include <sys/sx.h>
   58 #include <sys/sysctl.h>
   59 #include <sys/systm.h>
   60 
   61 #include <vm/uma.h>
   62 
   63 #include <net/if.h>
   64 #include <net/route.h>
   65 
   66 #include <netinet/in.h>
   67 #include <netinet/in_pcb.h>
   68 #include <netinet/in_systm.h>
   69 #include <netinet/in_var.h>
   70 #include <netinet/ip.h>
   71 #include <netinet/ip_divert.h>
   72 #include <netinet/ip_var.h>
   73 #include <netinet/ip_fw.h>
   74 
   75 /*
   76  * Divert sockets
   77  */
   78 
   79 /*
   80  * Allocate enough space to hold a full IP packet
   81  */
   82 #define DIVSNDQ         (65536 + 100)
   83 #define DIVRCVQ         (65536 + 100)
   84 
   85 /*
   86  * Divert sockets work in conjunction with ipfw, see the divert(4)
   87  * manpage for features.
   88  * Internally, packets selected by ipfw in ip_input() or ip_output(),
   89  * and never diverted before, are passed to the input queue of the
   90  * divert socket with a given 'divert_port' number (as specified in
   91  * the matching ipfw rule), and they are tagged with a 16 bit cookie
   92  * (representing the rule number of the matching ipfw rule), which
   93  * is passed to process reading from the socket.
   94  *
   95  * Packets written to the divert socket are again tagged with a cookie
   96  * (usually the same as above) and a destination address.
   97  * If the destination address is INADDR_ANY then the packet is
   98  * treated as outgoing and sent to ip_output(), otherwise it is
   99  * treated as incoming and sent to ip_input().
  100  * In both cases, the packet is tagged with the cookie.
  101  *
  102  * On reinjection, processing in ip_input() and ip_output()
  103  * will be exactly the same as for the original packet, except that
  104  * ipfw processing will start at the rule number after the one
  105  * written in the cookie (so, tagging a packet with a cookie of 0
  106  * will cause it to be effectively considered as a standard packet).
  107  */
  108 
  109 /* Internal variables. */
  110 static struct inpcbhead divcb;
  111 static struct inpcbinfo divcbinfo;
  112 
  113 static u_long   div_sendspace = DIVSNDQ;        /* XXX sysctl ? */
  114 static u_long   div_recvspace = DIVRCVQ;        /* XXX sysctl ? */
  115 
  116 /*
  117  * Initialize divert connection block queue.
  118  */
  119 void
  120 div_init(void)
  121 {
  122         INP_INFO_LOCK_INIT(&divcbinfo, "div");
  123         LIST_INIT(&divcb);
  124         divcbinfo.listhead = &divcb;
  125         /*
  126          * XXX We don't use the hash list for divert IP, but it's easier
  127          * to allocate a one entry hash list than it is to check all
  128          * over the place for hashbase == NULL.
  129          */
  130         divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
  131         divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
  132         divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb),
  133             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  134         uma_zone_set_max(divcbinfo.ipi_zone, maxsockets);
  135 }
  136 
  137 /*
  138  * IPPROTO_DIVERT is not in the real IP protocol number space; this
  139  * function should never be called.  Just in case, drop any packets.
  140  */
  141 void
  142 div_input(struct mbuf *m, int off)
  143 {
  144         ipstat.ips_noproto++;
  145         m_freem(m);
  146 }
  147 
  148 /*
  149  * Divert a packet by passing it up to the divert socket at port 'port'.
  150  *
  151  * Setup generic address and protocol structures for div_input routine,
  152  * then pass them along with mbuf chain.
  153  */
  154 static void
  155 divert_packet(struct mbuf *m, int incoming)
  156 {
  157         struct ip *ip;
  158         struct inpcb *inp;
  159         struct socket *sa;
  160         u_int16_t nport;
  161         struct sockaddr_in divsrc;
  162         struct m_tag *mtag;
  163 
  164         mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL);
  165         if (mtag == NULL) {
  166                 printf("%s: no divert tag\n", __func__);
  167                 m_freem(m);
  168                 return;
  169         }
  170         /* Assure header */
  171         if (m->m_len < sizeof(struct ip) &&
  172             (m = m_pullup(m, sizeof(struct ip))) == 0)
  173                 return;
  174         ip = mtod(m, struct ip *);
  175 
  176         /* Delayed checksums are currently not compatible with divert. */
  177         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  178                 ip->ip_len = ntohs(ip->ip_len);
  179                 in_delayed_cksum(m);
  180                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  181                 ip->ip_len = htons(ip->ip_len);
  182         }
  183 
  184         /*
  185          * Record receive interface address, if any.
  186          * But only for incoming packets.
  187          */
  188         bzero(&divsrc, sizeof(divsrc));
  189         divsrc.sin_len = sizeof(divsrc);
  190         divsrc.sin_family = AF_INET;
  191         divsrc.sin_port = divert_cookie(mtag);  /* record matching rule */
  192         if (incoming) {
  193                 struct ifaddr *ifa;
  194 
  195                 /* Sanity check */
  196                 M_ASSERTPKTHDR(m);
  197 
  198                 /* Find IP address for receive interface */
  199                 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
  200                         if (ifa->ifa_addr == NULL)
  201                                 continue;
  202                         if (ifa->ifa_addr->sa_family != AF_INET)
  203                                 continue;
  204                         divsrc.sin_addr =
  205                             ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
  206                         break;
  207                 }
  208         }
  209         /*
  210          * Record the incoming interface name whenever we have one.
  211          */
  212         if (m->m_pkthdr.rcvif) {
  213                 /*
  214                  * Hide the actual interface name in there in the 
  215                  * sin_zero array. XXX This needs to be moved to a
  216                  * different sockaddr type for divert, e.g.
  217                  * sockaddr_div with multiple fields like 
  218                  * sockaddr_dl. Presently we have only 7 bytes
  219                  * but that will do for now as most interfaces
  220                  * are 4 or less + 2 or less bytes for unit.
  221                  * There is probably a faster way of doing this,
  222                  * possibly taking it from the sockaddr_dl on the iface.
  223                  * This solves the problem of a P2P link and a LAN interface
  224                  * having the same address, which can result in the wrong
  225                  * interface being assigned to the packet when fed back
  226                  * into the divert socket. Theoretically if the daemon saves
  227                  * and re-uses the sockaddr_in as suggested in the man pages,
  228                  * this iface name will come along for the ride.
  229                  * (see div_output for the other half of this.)
  230                  */ 
  231                 strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
  232                     sizeof(divsrc.sin_zero));
  233         }
  234 
  235         /* Put packet on socket queue, if any */
  236         sa = NULL;
  237         nport = htons((u_int16_t)divert_info(mtag));
  238         INP_INFO_RLOCK(&divcbinfo);
  239         LIST_FOREACH(inp, &divcb, inp_list) {
  240                 INP_LOCK(inp);
  241                 /* XXX why does only one socket match? */
  242                 if (inp->inp_lport == nport) {
  243                         sa = inp->inp_socket;
  244                         SOCKBUF_LOCK(&sa->so_rcv);
  245                         if (sbappendaddr_locked(&sa->so_rcv,
  246                             (struct sockaddr *)&divsrc, m,
  247                             (struct mbuf *)0) == 0) {
  248                                 SOCKBUF_UNLOCK(&sa->so_rcv);
  249                                 sa = NULL;      /* force mbuf reclaim below */
  250                         } else
  251                                 sorwakeup_locked(sa);
  252                         INP_UNLOCK(inp);
  253                         break;
  254                 }
  255                 INP_UNLOCK(inp);
  256         }
  257         INP_INFO_RUNLOCK(&divcbinfo);
  258         if (sa == NULL) {
  259                 m_freem(m);
  260                 ipstat.ips_noproto++;
  261                 ipstat.ips_delivered--;
  262         }
  263 }
  264 
  265 /*
  266  * Deliver packet back into the IP processing machinery.
  267  *
  268  * If no address specified, or address is 0.0.0.0, send to ip_output();
  269  * otherwise, send to ip_input() and mark as having been received on
  270  * the interface with that address.
  271  */
  272 static int
  273 div_output(struct socket *so, struct mbuf *m,
  274         struct sockaddr_in *sin, struct mbuf *control)
  275 {
  276         struct m_tag *mtag;
  277         struct divert_tag *dt;
  278         int error = 0;
  279 
  280         /*
  281          * An mbuf may hasn't come from userland, but we pretend
  282          * that it has.
  283          */
  284         m->m_pkthdr.rcvif = NULL;
  285         m->m_nextpkt = NULL;
  286 
  287         if (control)
  288                 m_freem(control);               /* XXX */
  289 
  290         if ((mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL)) == NULL) {
  291                 mtag = m_tag_get(PACKET_TAG_DIVERT, sizeof(struct divert_tag),
  292                     M_NOWAIT | M_ZERO);
  293                 if (mtag == NULL) {
  294                         error = ENOBUFS;
  295                         goto cantsend;
  296                 }
  297                 dt = (struct divert_tag *)(mtag+1);
  298                 m_tag_prepend(m, mtag);
  299         } else
  300                 dt = (struct divert_tag *)(mtag+1);
  301 
  302         /* Loopback avoidance and state recovery */
  303         if (sin) {
  304                 int i;
  305 
  306                 dt->cookie = sin->sin_port;
  307                 /*
  308                  * Find receive interface with the given name, stuffed
  309                  * (if it exists) in the sin_zero[] field.
  310                  * The name is user supplied data so don't trust its size
  311                  * or that it is zero terminated.
  312                  */
  313                 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
  314                         ;
  315                 if ( i > 0 && i < sizeof(sin->sin_zero))
  316                         m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
  317         }
  318 
  319         /* Reinject packet into the system as incoming or outgoing */
  320         if (!sin || sin->sin_addr.s_addr == 0) {
  321                 struct ip *const ip = mtod(m, struct ip *);
  322                 struct inpcb *inp;
  323 
  324                 dt->info |= IP_FW_DIVERT_OUTPUT_FLAG;
  325                 INP_INFO_WLOCK(&divcbinfo);
  326                 inp = sotoinpcb(so);
  327                 INP_LOCK(inp);
  328                 /*
  329                  * Don't allow both user specified and setsockopt options,
  330                  * and don't allow packet length sizes that will crash
  331                  */
  332                 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
  333                      ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
  334                         error = EINVAL;
  335                         m_freem(m);
  336                 } else {
  337                         /* Convert fields to host order for ip_output() */
  338                         ip->ip_len = ntohs(ip->ip_len);
  339                         ip->ip_off = ntohs(ip->ip_off);
  340 
  341                         /* Send packet to output processing */
  342                         ipstat.ips_rawout++;                    /* XXX */
  343 
  344 #ifdef MAC
  345                         mac_create_mbuf_from_inpcb(inp, m);
  346 #endif
  347                         error = ip_output(m,
  348                                     inp->inp_options, NULL,
  349                                     ((so->so_options & SO_DONTROUTE) ?
  350                                     IP_ROUTETOIF : 0) |
  351                                     IP_ALLOWBROADCAST | IP_RAWOUTPUT,
  352                                     inp->inp_moptions, NULL);
  353                 }
  354                 INP_UNLOCK(inp);
  355                 INP_INFO_WUNLOCK(&divcbinfo);
  356         } else {
  357                 dt->info |= IP_FW_DIVERT_LOOPBACK_FLAG;
  358                 if (m->m_pkthdr.rcvif == NULL) {
  359                         /*
  360                          * No luck with the name, check by IP address.
  361                          * Clear the port and the ifname to make sure
  362                          * there are no distractions for ifa_ifwithaddr.
  363                          */
  364                         struct  ifaddr *ifa;
  365 
  366                         bzero(sin->sin_zero, sizeof(sin->sin_zero));
  367                         sin->sin_port = 0;
  368                         ifa = ifa_ifwithaddr((struct sockaddr *) sin);
  369                         if (ifa == NULL) {
  370                                 error = EADDRNOTAVAIL;
  371                                 goto cantsend;
  372                         }
  373                         m->m_pkthdr.rcvif = ifa->ifa_ifp;
  374                 }
  375 #ifdef MAC
  376                 SOCK_LOCK(so);
  377                 mac_create_mbuf_from_socket(so, m);
  378                 SOCK_UNLOCK(so);
  379 #endif
  380                 /* Send packet to input processing */
  381                 ip_input(m);
  382         }
  383 
  384         return error;
  385 
  386 cantsend:
  387         m_freem(m);
  388         return error;
  389 }
  390 
  391 static int
  392 div_attach(struct socket *so, int proto, struct thread *td)
  393 {
  394         struct inpcb *inp;
  395         int error;
  396 
  397         INP_INFO_WLOCK(&divcbinfo);
  398         inp  = sotoinpcb(so);
  399         if (inp != 0) {
  400                 INP_INFO_WUNLOCK(&divcbinfo);
  401                 return EINVAL;
  402         }
  403         if (td && (error = suser(td)) != 0) {
  404                 INP_INFO_WUNLOCK(&divcbinfo);
  405                 return error;
  406         }
  407         error = soreserve(so, div_sendspace, div_recvspace);
  408         if (error) {
  409                 INP_INFO_WUNLOCK(&divcbinfo);
  410                 return error;
  411         }
  412         error = in_pcballoc(so, &divcbinfo, "divinp");
  413         if (error) {
  414                 INP_INFO_WUNLOCK(&divcbinfo);
  415                 return error;
  416         }
  417         inp = (struct inpcb *)so->so_pcb;
  418         INP_LOCK(inp);
  419         INP_INFO_WUNLOCK(&divcbinfo);
  420         inp->inp_ip_p = proto;
  421         inp->inp_vflag |= INP_IPV4;
  422         inp->inp_flags |= INP_HDRINCL;
  423         INP_UNLOCK(inp);
  424         return 0;
  425 }
  426 
  427 static int
  428 div_detach(struct socket *so)
  429 {
  430         struct inpcb *inp;
  431 
  432         INP_INFO_WLOCK(&divcbinfo);
  433         inp = sotoinpcb(so);
  434         if (inp == 0) {
  435                 INP_INFO_WUNLOCK(&divcbinfo);
  436                 return EINVAL;
  437         }
  438         INP_LOCK(inp);
  439         in_pcbdetach(inp);
  440         INP_INFO_WUNLOCK(&divcbinfo);
  441         return 0;
  442 }
  443 
  444 static int
  445 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  446 {
  447         struct inpcb *inp;
  448         int error;
  449 
  450         INP_INFO_WLOCK(&divcbinfo);
  451         inp = sotoinpcb(so);
  452         if (inp == 0) {
  453                 INP_INFO_WUNLOCK(&divcbinfo);
  454                 return EINVAL;
  455         }
  456         /* in_pcbbind assumes that nam is a sockaddr_in
  457          * and in_pcbbind requires a valid address. Since divert
  458          * sockets don't we need to make sure the address is
  459          * filled in properly.
  460          * XXX -- divert should not be abusing in_pcbind
  461          * and should probably have its own family.
  462          */
  463         if (nam->sa_family != AF_INET)
  464                 error = EAFNOSUPPORT;
  465         else {
  466                 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
  467                 INP_LOCK(inp);
  468                 error = in_pcbbind(inp, nam, td->td_ucred);
  469                 INP_UNLOCK(inp);
  470         }
  471         INP_INFO_WUNLOCK(&divcbinfo);
  472         return error;
  473 }
  474 
  475 static int
  476 div_shutdown(struct socket *so)
  477 {
  478         struct inpcb *inp;
  479 
  480         INP_INFO_RLOCK(&divcbinfo);
  481         inp = sotoinpcb(so);
  482         if (inp == 0) {
  483                 INP_INFO_RUNLOCK(&divcbinfo);
  484                 return EINVAL;
  485         }
  486         INP_LOCK(inp);
  487         INP_INFO_RUNLOCK(&divcbinfo);
  488         socantsendmore(so);
  489         INP_UNLOCK(inp);
  490         return 0;
  491 }
  492 
  493 static int
  494 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
  495          struct mbuf *control, struct thread *td)
  496 {
  497         /* Packet must have a header (but that's about it) */
  498         if (m->m_len < sizeof (struct ip) &&
  499             (m = m_pullup(m, sizeof (struct ip))) == 0) {
  500                 ipstat.ips_toosmall++;
  501                 m_freem(m);
  502                 return EINVAL;
  503         }
  504 
  505         /* Send packet */
  506         return div_output(so, m, (struct sockaddr_in *)nam, control);
  507 }
  508 
  509 void
  510 div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
  511 {
  512         struct in_addr faddr;
  513 
  514         faddr = ((struct sockaddr_in *)sa)->sin_addr;
  515         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
  516                 return;
  517         if (PRC_IS_REDIRECT(cmd))
  518                 return;
  519 }
  520 
  521 static int
  522 div_pcblist(SYSCTL_HANDLER_ARGS)
  523 {
  524         int error, i, n;
  525         struct inpcb *inp, **inp_list;
  526         inp_gen_t gencnt;
  527         struct xinpgen xig;
  528 
  529         /*
  530          * The process of preparing the TCB list is too time-consuming and
  531          * resource-intensive to repeat twice on every request.
  532          */
  533         if (req->oldptr == 0) {
  534                 n = divcbinfo.ipi_count;
  535                 req->oldidx = 2 * (sizeof xig)
  536                         + (n + n/8) * sizeof(struct xinpcb);
  537                 return 0;
  538         }
  539 
  540         if (req->newptr != 0)
  541                 return EPERM;
  542 
  543         /*
  544          * OK, now we're committed to doing something.
  545          */
  546         INP_INFO_RLOCK(&divcbinfo);
  547         gencnt = divcbinfo.ipi_gencnt;
  548         n = divcbinfo.ipi_count;
  549         INP_INFO_RUNLOCK(&divcbinfo);
  550 
  551         error = sysctl_wire_old_buffer(req,
  552             2 * sizeof(xig) + n*sizeof(struct xinpcb));
  553         if (error != 0)
  554                 return (error);
  555 
  556         xig.xig_len = sizeof xig;
  557         xig.xig_count = n;
  558         xig.xig_gen = gencnt;
  559         xig.xig_sogen = so_gencnt;
  560         error = SYSCTL_OUT(req, &xig, sizeof xig);
  561         if (error)
  562                 return error;
  563 
  564         inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
  565         if (inp_list == 0)
  566                 return ENOMEM;
  567         
  568         INP_INFO_RLOCK(&divcbinfo);
  569         for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n;
  570              inp = LIST_NEXT(inp, inp_list)) {
  571                 INP_LOCK(inp);
  572                 if (inp->inp_gencnt <= gencnt &&
  573                     cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
  574                         inp_list[i++] = inp;
  575                 INP_UNLOCK(inp);
  576         }
  577         INP_INFO_RUNLOCK(&divcbinfo);
  578         n = i;
  579 
  580         error = 0;
  581         for (i = 0; i < n; i++) {
  582                 inp = inp_list[i];
  583                 if (inp->inp_gencnt <= gencnt) {
  584                         struct xinpcb xi;
  585                         bzero(&xi, sizeof(xi));
  586                         xi.xi_len = sizeof xi;
  587                         /* XXX should avoid extra copy */
  588                         bcopy(inp, &xi.xi_inp, sizeof *inp);
  589                         if (inp->inp_socket)
  590                                 sotoxsocket(inp->inp_socket, &xi.xi_socket);
  591                         error = SYSCTL_OUT(req, &xi, sizeof xi);
  592                 }
  593         }
  594         if (!error) {
  595                 /*
  596                  * Give the user an updated idea of our state.
  597                  * If the generation differs from what we told
  598                  * her before, she knows that something happened
  599                  * while we were processing this request, and it
  600                  * might be necessary to retry.
  601                  */
  602                 INP_INFO_RLOCK(&divcbinfo);
  603                 xig.xig_gen = divcbinfo.ipi_gencnt;
  604                 xig.xig_sogen = so_gencnt;
  605                 xig.xig_count = divcbinfo.ipi_count;
  606                 INP_INFO_RUNLOCK(&divcbinfo);
  607                 error = SYSCTL_OUT(req, &xig, sizeof xig);
  608         }
  609         free(inp_list, M_TEMP);
  610         return error;
  611 }
  612 
  613 /*
  614  * This is the wrapper function for in_setsockaddr.  We just pass down
  615  * the pcbinfo for in_setpeeraddr to lock.
  616  */
  617 static int
  618 div_sockaddr(struct socket *so, struct sockaddr **nam)
  619 {
  620         return (in_setsockaddr(so, nam, &divcbinfo));
  621 }
  622 
  623 /*
  624  * This is the wrapper function for in_setpeeraddr. We just pass down
  625  * the pcbinfo for in_setpeeraddr to lock.
  626  */
  627 static int
  628 div_peeraddr(struct socket *so, struct sockaddr **nam)
  629 {
  630         return (in_setpeeraddr(so, nam, &divcbinfo));
  631 }
  632 
  633 #ifdef SYSCTL_NODE
  634 SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0, "IPDIVERT");
  635 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0,
  636             div_pcblist, "S,xinpcb", "List of active divert sockets");
  637 #endif
  638 
  639 struct pr_usrreqs div_usrreqs = {
  640         .pru_attach =           div_attach,
  641         .pru_bind =             div_bind,
  642         .pru_control =          in_control,
  643         .pru_detach =           div_detach,
  644         .pru_peeraddr =         div_peeraddr,
  645         .pru_send =             div_send,
  646         .pru_shutdown =         div_shutdown,
  647         .pru_sockaddr =         div_sockaddr,
  648         .pru_sosetlabel =       in_pcbsosetlabel
  649 };
  650 
  651 struct protosw div_protosw = {
  652   SOCK_RAW,     NULL,           IPPROTO_DIVERT, PR_ATOMIC|PR_ADDR,
  653   div_input,    NULL,           div_ctlinput,   ip_ctloutput,
  654   NULL,
  655   div_init,     NULL,           NULL,           NULL,
  656   &div_usrreqs
  657 };
  658 
  659 static int
  660 div_modevent(module_t mod, int type, void *unused)
  661 {
  662         int err = 0;
  663         int n;
  664 
  665         switch (type) {
  666         case MOD_LOAD:
  667                 /*
  668                  * Protocol will be initialized by pf_proto_register().
  669                  * We don't have to register ip_protox because we are not
  670                  * a true IP protocol that goes over the wire.
  671                  */
  672                 err = pf_proto_register(PF_INET, &div_protosw);
  673                 ip_divert_ptr = divert_packet;
  674                 break;
  675         case MOD_QUIESCE:
  676                 /*
  677                  * IPDIVERT may normally not be unloaded because of the
  678                  * potential race conditions.  Tell kldunload we can't be
  679                  * unloaded unless the unload is forced.
  680                  */
  681                 err = EPERM;
  682                 break;
  683         case MOD_UNLOAD:
  684                 /*
  685                  * Forced unload.
  686                  *
  687                  * Module ipdivert can only be unloaded if no sockets are
  688                  * connected.  Maybe this can be changed later to forcefully
  689                  * disconnect any open sockets.
  690                  *
  691                  * XXXRW: Note that there is a slight race here, as a new
  692                  * socket open request could be spinning on the lock and then
  693                  * we destroy the lock.
  694                  */
  695                 INP_INFO_WLOCK(&divcbinfo);
  696                 n = divcbinfo.ipi_count;
  697                 if (n != 0) {
  698                         err = EBUSY;
  699                         INP_INFO_WUNLOCK(&divcbinfo);
  700                         break;
  701                 }
  702                 ip_divert_ptr = NULL;
  703                 err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
  704                 INP_INFO_WUNLOCK(&divcbinfo);
  705                 INP_INFO_LOCK_DESTROY(&divcbinfo);
  706                 uma_zdestroy(divcbinfo.ipi_zone);
  707                 break;
  708         default:
  709                 err = EOPNOTSUPP;
  710                 break;
  711         }
  712         return err;
  713 }
  714 
  715 static moduledata_t ipdivertmod = {
  716         "ipdivert",
  717         div_modevent,
  718         0
  719 };
  720 
  721 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  722 MODULE_DEPEND(dummynet, ipfw, 2, 2, 2);
  723 MODULE_VERSION(ipdivert, 1);

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