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 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/10.2/sys/netinet/ip_divert.c 241913 2012-10-22 21:09:03Z glebius $");
   32 
   33 #include "opt_inet.h"
   34 #include "opt_inet6.h"
   35 #include "opt_sctp.h"
   36 #ifndef INET
   37 #error "IPDIVERT requires INET"
   38 #endif
   39 
   40 #include <sys/param.h>
   41 #include <sys/kernel.h>
   42 #include <sys/lock.h>
   43 #include <sys/malloc.h>
   44 #include <sys/mbuf.h>
   45 #include <sys/module.h>
   46 #include <sys/kernel.h>
   47 #include <sys/priv.h>
   48 #include <sys/proc.h>
   49 #include <sys/protosw.h>
   50 #include <sys/socket.h>
   51 #include <sys/socketvar.h>
   52 #include <sys/sysctl.h>
   53 #include <net/vnet.h>
   54 
   55 #include <net/if.h>
   56 #include <net/netisr.h> 
   57 
   58 #include <netinet/in.h>
   59 #include <netinet/in_pcb.h>
   60 #include <netinet/in_systm.h>
   61 #include <netinet/in_var.h>
   62 #include <netinet/ip.h>
   63 #include <netinet/ip_var.h>
   64 #ifdef INET6
   65 #include <netinet/ip6.h>
   66 #include <netinet6/ip6_var.h>
   67 #endif
   68 #ifdef SCTP
   69 #include <netinet/sctp_crc32.h>
   70 #endif
   71 
   72 #include <security/mac/mac_framework.h>
   73 
   74 /*
   75  * Divert sockets
   76  */
   77 
   78 /*
   79  * Allocate enough space to hold a full IP packet
   80  */
   81 #define DIVSNDQ         (65536 + 100)
   82 #define DIVRCVQ         (65536 + 100)
   83 
   84 /*
   85  * Divert sockets work in conjunction with ipfw or other packet filters,
   86  * see the divert(4) manpage for features.
   87  * Packets are selected by the packet filter and tagged with an
   88  * MTAG_IPFW_RULE tag carrying the 'divert port' number (as set by
   89  * the packet filter) and information on the matching filter rule for
   90  * subsequent reinjection. The divert_port is used to put the packet
   91  * on the corresponding divert socket, while the rule number is passed
   92  * up (at least partially) as the sin_port in the struct sockaddr.
   93  *
   94  * Packets written to the divert socket carry in sin_addr a
   95  * destination address, and in sin_port the number of the filter rule
   96  * after which to continue processing.
   97  * If the destination address is INADDR_ANY, the packet is treated as
   98  * as outgoing and sent to ip_output(); otherwise it is treated as
   99  * incoming and sent to ip_input().
  100  * Further, sin_zero carries some information on the interface,
  101  * which can be used in the reinject -- see comments in the code.
  102  *
  103  * On reinjection, processing in ip_input() and ip_output()
  104  * will be exactly the same as for the original packet, except that
  105  * packet filter processing will start at the rule number after the one
  106  * written in the sin_port (ipfw does not allow a rule #0, so sin_port=0
  107  * will apply the entire ruleset to the packet).
  108  */
  109 
  110 /* Internal variables. */
  111 static VNET_DEFINE(struct inpcbhead, divcb);
  112 static VNET_DEFINE(struct inpcbinfo, divcbinfo);
  113 
  114 #define V_divcb                         VNET(divcb)
  115 #define V_divcbinfo                     VNET(divcbinfo)
  116 
  117 static u_long   div_sendspace = DIVSNDQ;        /* XXX sysctl ? */
  118 static u_long   div_recvspace = DIVRCVQ;        /* XXX sysctl ? */
  119 
  120 static eventhandler_tag ip_divert_event_tag;
  121 
  122 /*
  123  * Initialize divert connection block queue.
  124  */
  125 static void
  126 div_zone_change(void *tag)
  127 {
  128 
  129         uma_zone_set_max(V_divcbinfo.ipi_zone, maxsockets);
  130 }
  131 
  132 static int
  133 div_inpcb_init(void *mem, int size, int flags)
  134 {
  135         struct inpcb *inp = mem;
  136 
  137         INP_LOCK_INIT(inp, "inp", "divinp");
  138         return (0);
  139 }
  140 
  141 static void
  142 div_inpcb_fini(void *mem, int size)
  143 {
  144         struct inpcb *inp = mem;
  145 
  146         INP_LOCK_DESTROY(inp);
  147 }
  148 
  149 static void
  150 div_init(void)
  151 {
  152 
  153         /*
  154          * XXX We don't use the hash list for divert IP, but it's easier to
  155          * allocate one-entry hash lists than it is to check all over the
  156          * place for hashbase == NULL.
  157          */
  158         in_pcbinfo_init(&V_divcbinfo, "div", &V_divcb, 1, 1, "divcb",
  159             div_inpcb_init, div_inpcb_fini, UMA_ZONE_NOFREE,
  160             IPI_HASHFIELDS_NONE);
  161 }
  162 
  163 static void
  164 div_destroy(void)
  165 {
  166 
  167         in_pcbinfo_destroy(&V_divcbinfo);
  168 }
  169 
  170 /*
  171  * IPPROTO_DIVERT is not in the real IP protocol number space; this
  172  * function should never be called.  Just in case, drop any packets.
  173  */
  174 static void
  175 div_input(struct mbuf *m, int off)
  176 {
  177 
  178         KMOD_IPSTAT_INC(ips_noproto);
  179         m_freem(m);
  180 }
  181 
  182 /*
  183  * Divert a packet by passing it up to the divert socket at port 'port'.
  184  *
  185  * Setup generic address and protocol structures for div_input routine,
  186  * then pass them along with mbuf chain.
  187  */
  188 static void
  189 divert_packet(struct mbuf *m, int incoming)
  190 {
  191         struct ip *ip;
  192         struct inpcb *inp;
  193         struct socket *sa;
  194         u_int16_t nport;
  195         struct sockaddr_in divsrc;
  196         struct m_tag *mtag;
  197 
  198         mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
  199         if (mtag == NULL) {
  200                 m_freem(m);
  201                 return;
  202         }
  203         /* Assure header */
  204         if (m->m_len < sizeof(struct ip) &&
  205             (m = m_pullup(m, sizeof(struct ip))) == 0)
  206                 return;
  207         ip = mtod(m, struct ip *);
  208 
  209         /* Delayed checksums are currently not compatible with divert. */
  210         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  211                 in_delayed_cksum(m);
  212                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  213         }
  214 #ifdef SCTP
  215         if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
  216                 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
  217                 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
  218         }
  219 #endif
  220         bzero(&divsrc, sizeof(divsrc));
  221         divsrc.sin_len = sizeof(divsrc);
  222         divsrc.sin_family = AF_INET;
  223         /* record matching rule, in host format */
  224         divsrc.sin_port = ((struct ipfw_rule_ref *)(mtag+1))->rulenum;
  225         /*
  226          * Record receive interface address, if any.
  227          * But only for incoming packets.
  228          */
  229         if (incoming) {
  230                 struct ifaddr *ifa;
  231                 struct ifnet *ifp;
  232 
  233                 /* Sanity check */
  234                 M_ASSERTPKTHDR(m);
  235 
  236                 /* Find IP address for receive interface */
  237                 ifp = m->m_pkthdr.rcvif;
  238                 if_addr_rlock(ifp);
  239                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  240                         if (ifa->ifa_addr->sa_family != AF_INET)
  241                                 continue;
  242                         divsrc.sin_addr =
  243                             ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
  244                         break;
  245                 }
  246                 if_addr_runlock(ifp);
  247         }
  248         /*
  249          * Record the incoming interface name whenever we have one.
  250          */
  251         if (m->m_pkthdr.rcvif) {
  252                 /*
  253                  * Hide the actual interface name in there in the 
  254                  * sin_zero array. XXX This needs to be moved to a
  255                  * different sockaddr type for divert, e.g.
  256                  * sockaddr_div with multiple fields like 
  257                  * sockaddr_dl. Presently we have only 7 bytes
  258                  * but that will do for now as most interfaces
  259                  * are 4 or less + 2 or less bytes for unit.
  260                  * There is probably a faster way of doing this,
  261                  * possibly taking it from the sockaddr_dl on the iface.
  262                  * This solves the problem of a P2P link and a LAN interface
  263                  * having the same address, which can result in the wrong
  264                  * interface being assigned to the packet when fed back
  265                  * into the divert socket. Theoretically if the daemon saves
  266                  * and re-uses the sockaddr_in as suggested in the man pages,
  267                  * this iface name will come along for the ride.
  268                  * (see div_output for the other half of this.)
  269                  */ 
  270                 strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
  271                     sizeof(divsrc.sin_zero));
  272         }
  273 
  274         /* Put packet on socket queue, if any */
  275         sa = NULL;
  276         nport = htons((u_int16_t)(((struct ipfw_rule_ref *)(mtag+1))->info));
  277         INP_INFO_RLOCK(&V_divcbinfo);
  278         LIST_FOREACH(inp, &V_divcb, inp_list) {
  279                 /* XXX why does only one socket match? */
  280                 if (inp->inp_lport == nport) {
  281                         INP_RLOCK(inp);
  282                         sa = inp->inp_socket;
  283                         SOCKBUF_LOCK(&sa->so_rcv);
  284                         if (sbappendaddr_locked(&sa->so_rcv,
  285                             (struct sockaddr *)&divsrc, m,
  286                             (struct mbuf *)0) == 0) {
  287                                 SOCKBUF_UNLOCK(&sa->so_rcv);
  288                                 sa = NULL;      /* force mbuf reclaim below */
  289                         } else
  290                                 sorwakeup_locked(sa);
  291                         INP_RUNLOCK(inp);
  292                         break;
  293                 }
  294         }
  295         INP_INFO_RUNLOCK(&V_divcbinfo);
  296         if (sa == NULL) {
  297                 m_freem(m);
  298                 KMOD_IPSTAT_INC(ips_noproto);
  299                 KMOD_IPSTAT_DEC(ips_delivered);
  300         }
  301 }
  302 
  303 /*
  304  * Deliver packet back into the IP processing machinery.
  305  *
  306  * If no address specified, or address is 0.0.0.0, send to ip_output();
  307  * otherwise, send to ip_input() and mark as having been received on
  308  * the interface with that address.
  309  */
  310 static int
  311 div_output(struct socket *so, struct mbuf *m, struct sockaddr_in *sin,
  312     struct mbuf *control)
  313 {
  314         struct ip *const ip = mtod(m, struct ip *);
  315         struct m_tag *mtag;
  316         struct ipfw_rule_ref *dt;
  317         int error = 0;
  318 
  319         /*
  320          * An mbuf may hasn't come from userland, but we pretend
  321          * that it has.
  322          */
  323         m->m_pkthdr.rcvif = NULL;
  324         m->m_nextpkt = NULL;
  325         M_SETFIB(m, so->so_fibnum);
  326 
  327         if (control)
  328                 m_freem(control);               /* XXX */
  329 
  330         mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
  331         if (mtag == NULL) {
  332                 /* this should be normal */
  333                 mtag = m_tag_alloc(MTAG_IPFW_RULE, 0,
  334                     sizeof(struct ipfw_rule_ref), M_NOWAIT | M_ZERO);
  335                 if (mtag == NULL) {
  336                         error = ENOBUFS;
  337                         goto cantsend;
  338                 }
  339                 m_tag_prepend(m, mtag);
  340         }
  341         dt = (struct ipfw_rule_ref *)(mtag+1);
  342 
  343         /* Loopback avoidance and state recovery */
  344         if (sin) {
  345                 int i;
  346 
  347                 /* set the starting point. We provide a non-zero slot,
  348                  * but a non_matching chain_id to skip that info and use
  349                  * the rulenum/rule_id.
  350                  */
  351                 dt->slot = 1; /* dummy, chain_id is invalid */
  352                 dt->chain_id = 0;
  353                 dt->rulenum = sin->sin_port+1; /* host format ? */
  354                 dt->rule_id = 0;
  355                 /*
  356                  * Find receive interface with the given name, stuffed
  357                  * (if it exists) in the sin_zero[] field.
  358                  * The name is user supplied data so don't trust its size
  359                  * or that it is zero terminated.
  360                  */
  361                 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
  362                         ;
  363                 if ( i > 0 && i < sizeof(sin->sin_zero))
  364                         m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
  365         }
  366 
  367         /* Reinject packet into the system as incoming or outgoing */
  368         if (!sin || sin->sin_addr.s_addr == 0) {
  369                 struct mbuf *options = NULL;
  370                 struct inpcb *inp;
  371 
  372                 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_OUT;
  373                 inp = sotoinpcb(so);
  374                 INP_RLOCK(inp);
  375                 switch (ip->ip_v) {
  376                 case IPVERSION:
  377                         /*
  378                          * Don't allow both user specified and setsockopt
  379                          * options, and don't allow packet length sizes that
  380                          * will crash.
  381                          */
  382                         if ((((ip->ip_hl << 2) != sizeof(struct ip)) &&
  383                             inp->inp_options != NULL) ||
  384                             ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
  385                                 error = EINVAL;
  386                                 INP_RUNLOCK(inp);
  387                                 goto cantsend;
  388                         }
  389                         break;
  390 #ifdef INET6
  391                 case IPV6_VERSION >> 4:
  392                     {
  393                         struct ip6_hdr *const ip6 = mtod(m, struct ip6_hdr *);
  394 
  395                         /* Don't allow packet length sizes that will crash */
  396                         if (((u_short)ntohs(ip6->ip6_plen) > m->m_pkthdr.len)) {
  397                                 error = EINVAL;
  398                                 INP_RUNLOCK(inp);
  399                                 goto cantsend;
  400                         }
  401                         break;
  402                     }
  403 #endif
  404                 default:
  405                         error = EINVAL;
  406                         INP_RUNLOCK(inp);
  407                         goto cantsend;
  408                 }
  409 
  410                 /* Send packet to output processing */
  411                 KMOD_IPSTAT_INC(ips_rawout);            /* XXX */
  412 
  413 #ifdef MAC
  414                 mac_inpcb_create_mbuf(inp, m);
  415 #endif
  416                 /*
  417                  * Get ready to inject the packet into ip_output().
  418                  * Just in case socket options were specified on the
  419                  * divert socket, we duplicate them.  This is done
  420                  * to avoid having to hold the PCB locks over the call
  421                  * to ip_output(), as doing this results in a number of
  422                  * lock ordering complexities.
  423                  *
  424                  * Note that we set the multicast options argument for
  425                  * ip_output() to NULL since it should be invariant that
  426                  * they are not present.
  427                  */
  428                 KASSERT(inp->inp_moptions == NULL,
  429                     ("multicast options set on a divert socket"));
  430                 /*
  431                  * XXXCSJP: It is unclear to me whether or not it makes
  432                  * sense for divert sockets to have options.  However,
  433                  * for now we will duplicate them with the INP locks
  434                  * held so we can use them in ip_output() without
  435                  * requring a reference to the pcb.
  436                  */
  437                 if (inp->inp_options != NULL) {
  438                         options = m_dup(inp->inp_options, M_NOWAIT);
  439                         if (options == NULL) {
  440                                 INP_RUNLOCK(inp);
  441                                 error = ENOBUFS;
  442                                 goto cantsend;
  443                         }
  444                 }
  445                 INP_RUNLOCK(inp);
  446 
  447                 switch (ip->ip_v) {
  448                 case IPVERSION:
  449                         error = ip_output(m, options, NULL,
  450                             ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0)
  451                             | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL);
  452                         break;
  453 #ifdef INET6
  454                 case IPV6_VERSION >> 4:
  455                         error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  456                         break;
  457 #endif
  458                 }
  459                 if (options != NULL)
  460                         m_freem(options);
  461         } else {
  462                 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_IN;
  463                 if (m->m_pkthdr.rcvif == NULL) {
  464                         /*
  465                          * No luck with the name, check by IP address.
  466                          * Clear the port and the ifname to make sure
  467                          * there are no distractions for ifa_ifwithaddr.
  468                          */
  469                         struct  ifaddr *ifa;
  470 
  471                         bzero(sin->sin_zero, sizeof(sin->sin_zero));
  472                         sin->sin_port = 0;
  473                         ifa = ifa_ifwithaddr((struct sockaddr *) sin);
  474                         if (ifa == NULL) {
  475                                 error = EADDRNOTAVAIL;
  476                                 goto cantsend;
  477                         }
  478                         m->m_pkthdr.rcvif = ifa->ifa_ifp;
  479                         ifa_free(ifa);
  480                 }
  481 #ifdef MAC
  482                 mac_socket_create_mbuf(so, m);
  483 #endif
  484                 /* Send packet to input processing via netisr */
  485                 switch (ip->ip_v) {
  486                 case IPVERSION:
  487                         netisr_queue_src(NETISR_IP, (uintptr_t)so, m);
  488                         break;
  489 #ifdef INET6
  490                 case IPV6_VERSION >> 4:
  491                         netisr_queue_src(NETISR_IPV6, (uintptr_t)so, m);
  492                         break;
  493 #endif
  494                 default:
  495                         error = EINVAL;
  496                         goto cantsend;
  497                 }
  498         }
  499 
  500         return (error);
  501 
  502 cantsend:
  503         m_freem(m);
  504         return (error);
  505 }
  506 
  507 static int
  508 div_attach(struct socket *so, int proto, struct thread *td)
  509 {
  510         struct inpcb *inp;
  511         int error;
  512 
  513         inp  = sotoinpcb(so);
  514         KASSERT(inp == NULL, ("div_attach: inp != NULL"));
  515         if (td != NULL) {
  516                 error = priv_check(td, PRIV_NETINET_DIVERT);
  517                 if (error)
  518                         return (error);
  519         }
  520         error = soreserve(so, div_sendspace, div_recvspace);
  521         if (error)
  522                 return error;
  523         INP_INFO_WLOCK(&V_divcbinfo);
  524         error = in_pcballoc(so, &V_divcbinfo);
  525         if (error) {
  526                 INP_INFO_WUNLOCK(&V_divcbinfo);
  527                 return error;
  528         }
  529         inp = (struct inpcb *)so->so_pcb;
  530         INP_INFO_WUNLOCK(&V_divcbinfo);
  531         inp->inp_ip_p = proto;
  532         inp->inp_vflag |= INP_IPV4;
  533         inp->inp_flags |= INP_HDRINCL;
  534         INP_WUNLOCK(inp);
  535         return 0;
  536 }
  537 
  538 static void
  539 div_detach(struct socket *so)
  540 {
  541         struct inpcb *inp;
  542 
  543         inp = sotoinpcb(so);
  544         KASSERT(inp != NULL, ("div_detach: inp == NULL"));
  545         INP_INFO_WLOCK(&V_divcbinfo);
  546         INP_WLOCK(inp);
  547         in_pcbdetach(inp);
  548         in_pcbfree(inp);
  549         INP_INFO_WUNLOCK(&V_divcbinfo);
  550 }
  551 
  552 static int
  553 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  554 {
  555         struct inpcb *inp;
  556         int error;
  557 
  558         inp = sotoinpcb(so);
  559         KASSERT(inp != NULL, ("div_bind: inp == NULL"));
  560         /* in_pcbbind assumes that nam is a sockaddr_in
  561          * and in_pcbbind requires a valid address. Since divert
  562          * sockets don't we need to make sure the address is
  563          * filled in properly.
  564          * XXX -- divert should not be abusing in_pcbind
  565          * and should probably have its own family.
  566          */
  567         if (nam->sa_family != AF_INET)
  568                 return EAFNOSUPPORT;
  569         ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
  570         INP_INFO_WLOCK(&V_divcbinfo);
  571         INP_WLOCK(inp);
  572         INP_HASH_WLOCK(&V_divcbinfo);
  573         error = in_pcbbind(inp, nam, td->td_ucred);
  574         INP_HASH_WUNLOCK(&V_divcbinfo);
  575         INP_WUNLOCK(inp);
  576         INP_INFO_WUNLOCK(&V_divcbinfo);
  577         return error;
  578 }
  579 
  580 static int
  581 div_shutdown(struct socket *so)
  582 {
  583         struct inpcb *inp;
  584 
  585         inp = sotoinpcb(so);
  586         KASSERT(inp != NULL, ("div_shutdown: inp == NULL"));
  587         INP_WLOCK(inp);
  588         socantsendmore(so);
  589         INP_WUNLOCK(inp);
  590         return 0;
  591 }
  592 
  593 static int
  594 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
  595     struct mbuf *control, struct thread *td)
  596 {
  597 
  598         /* Packet must have a header (but that's about it) */
  599         if (m->m_len < sizeof (struct ip) &&
  600             (m = m_pullup(m, sizeof (struct ip))) == 0) {
  601                 KMOD_IPSTAT_INC(ips_toosmall);
  602                 m_freem(m);
  603                 return EINVAL;
  604         }
  605 
  606         /* Send packet */
  607         return div_output(so, m, (struct sockaddr_in *)nam, control);
  608 }
  609 
  610 static void
  611 div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
  612 {
  613         struct in_addr faddr;
  614 
  615         faddr = ((struct sockaddr_in *)sa)->sin_addr;
  616         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
  617                 return;
  618         if (PRC_IS_REDIRECT(cmd))
  619                 return;
  620 }
  621 
  622 static int
  623 div_pcblist(SYSCTL_HANDLER_ARGS)
  624 {
  625         int error, i, n;
  626         struct inpcb *inp, **inp_list;
  627         inp_gen_t gencnt;
  628         struct xinpgen xig;
  629 
  630         /*
  631          * The process of preparing the TCB list is too time-consuming and
  632          * resource-intensive to repeat twice on every request.
  633          */
  634         if (req->oldptr == 0) {
  635                 n = V_divcbinfo.ipi_count;
  636                 n += imax(n / 8, 10);
  637                 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb);
  638                 return 0;
  639         }
  640 
  641         if (req->newptr != 0)
  642                 return EPERM;
  643 
  644         /*
  645          * OK, now we're committed to doing something.
  646          */
  647         INP_INFO_RLOCK(&V_divcbinfo);
  648         gencnt = V_divcbinfo.ipi_gencnt;
  649         n = V_divcbinfo.ipi_count;
  650         INP_INFO_RUNLOCK(&V_divcbinfo);
  651 
  652         error = sysctl_wire_old_buffer(req,
  653             2 * sizeof(xig) + n*sizeof(struct xinpcb));
  654         if (error != 0)
  655                 return (error);
  656 
  657         xig.xig_len = sizeof xig;
  658         xig.xig_count = n;
  659         xig.xig_gen = gencnt;
  660         xig.xig_sogen = so_gencnt;
  661         error = SYSCTL_OUT(req, &xig, sizeof xig);
  662         if (error)
  663                 return error;
  664 
  665         inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
  666         if (inp_list == 0)
  667                 return ENOMEM;
  668         
  669         INP_INFO_RLOCK(&V_divcbinfo);
  670         for (inp = LIST_FIRST(V_divcbinfo.ipi_listhead), i = 0; inp && i < n;
  671              inp = LIST_NEXT(inp, inp_list)) {
  672                 INP_WLOCK(inp);
  673                 if (inp->inp_gencnt <= gencnt &&
  674                     cr_canseeinpcb(req->td->td_ucred, inp) == 0) {
  675                         in_pcbref(inp);
  676                         inp_list[i++] = inp;
  677                 }
  678                 INP_WUNLOCK(inp);
  679         }
  680         INP_INFO_RUNLOCK(&V_divcbinfo);
  681         n = i;
  682 
  683         error = 0;
  684         for (i = 0; i < n; i++) {
  685                 inp = inp_list[i];
  686                 INP_RLOCK(inp);
  687                 if (inp->inp_gencnt <= gencnt) {
  688                         struct xinpcb xi;
  689                         bzero(&xi, sizeof(xi));
  690                         xi.xi_len = sizeof xi;
  691                         /* XXX should avoid extra copy */
  692                         bcopy(inp, &xi.xi_inp, sizeof *inp);
  693                         if (inp->inp_socket)
  694                                 sotoxsocket(inp->inp_socket, &xi.xi_socket);
  695                         INP_RUNLOCK(inp);
  696                         error = SYSCTL_OUT(req, &xi, sizeof xi);
  697                 } else
  698                         INP_RUNLOCK(inp);
  699         }
  700         INP_INFO_WLOCK(&V_divcbinfo);
  701         for (i = 0; i < n; i++) {
  702                 inp = inp_list[i];
  703                 INP_RLOCK(inp);
  704                 if (!in_pcbrele_rlocked(inp))
  705                         INP_RUNLOCK(inp);
  706         }
  707         INP_INFO_WUNLOCK(&V_divcbinfo);
  708 
  709         if (!error) {
  710                 /*
  711                  * Give the user an updated idea of our state.
  712                  * If the generation differs from what we told
  713                  * her before, she knows that something happened
  714                  * while we were processing this request, and it
  715                  * might be necessary to retry.
  716                  */
  717                 INP_INFO_RLOCK(&V_divcbinfo);
  718                 xig.xig_gen = V_divcbinfo.ipi_gencnt;
  719                 xig.xig_sogen = so_gencnt;
  720                 xig.xig_count = V_divcbinfo.ipi_count;
  721                 INP_INFO_RUNLOCK(&V_divcbinfo);
  722                 error = SYSCTL_OUT(req, &xig, sizeof xig);
  723         }
  724         free(inp_list, M_TEMP);
  725         return error;
  726 }
  727 
  728 #ifdef SYSCTL_NODE
  729 static SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0,
  730     "IPDIVERT");
  731 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
  732     NULL, 0, div_pcblist, "S,xinpcb", "List of active divert sockets");
  733 #endif
  734 
  735 struct pr_usrreqs div_usrreqs = {
  736         .pru_attach =           div_attach,
  737         .pru_bind =             div_bind,
  738         .pru_control =          in_control,
  739         .pru_detach =           div_detach,
  740         .pru_peeraddr =         in_getpeeraddr,
  741         .pru_send =             div_send,
  742         .pru_shutdown =         div_shutdown,
  743         .pru_sockaddr =         in_getsockaddr,
  744         .pru_sosetlabel =       in_pcbsosetlabel
  745 };
  746 
  747 struct protosw div_protosw = {
  748         .pr_type =              SOCK_RAW,
  749         .pr_protocol =          IPPROTO_DIVERT,
  750         .pr_flags =             PR_ATOMIC|PR_ADDR,
  751         .pr_input =             div_input,
  752         .pr_ctlinput =          div_ctlinput,
  753         .pr_ctloutput =         ip_ctloutput,
  754         .pr_init =              div_init,
  755 #ifdef VIMAGE
  756         .pr_destroy =           div_destroy,
  757 #endif
  758         .pr_usrreqs =           &div_usrreqs
  759 };
  760 
  761 static int
  762 div_modevent(module_t mod, int type, void *unused)
  763 {
  764         int err = 0;
  765 #ifndef VIMAGE
  766         int n;
  767 #endif
  768 
  769         switch (type) {
  770         case MOD_LOAD:
  771                 /*
  772                  * Protocol will be initialized by pf_proto_register().
  773                  * We don't have to register ip_protox because we are not
  774                  * a true IP protocol that goes over the wire.
  775                  */
  776                 err = pf_proto_register(PF_INET, &div_protosw);
  777                 if (err != 0)
  778                         return (err);
  779                 ip_divert_ptr = divert_packet;
  780                 ip_divert_event_tag = EVENTHANDLER_REGISTER(maxsockets_change,
  781                     div_zone_change, NULL, EVENTHANDLER_PRI_ANY);
  782                 break;
  783         case MOD_QUIESCE:
  784                 /*
  785                  * IPDIVERT may normally not be unloaded because of the
  786                  * potential race conditions.  Tell kldunload we can't be
  787                  * unloaded unless the unload is forced.
  788                  */
  789                 err = EPERM;
  790                 break;
  791         case MOD_UNLOAD:
  792 #ifdef VIMAGE
  793                 err = EPERM;
  794                 break;
  795 #else
  796                 /*
  797                  * Forced unload.
  798                  *
  799                  * Module ipdivert can only be unloaded if no sockets are
  800                  * connected.  Maybe this can be changed later to forcefully
  801                  * disconnect any open sockets.
  802                  *
  803                  * XXXRW: Note that there is a slight race here, as a new
  804                  * socket open request could be spinning on the lock and then
  805                  * we destroy the lock.
  806                  */
  807                 INP_INFO_WLOCK(&V_divcbinfo);
  808                 n = V_divcbinfo.ipi_count;
  809                 if (n != 0) {
  810                         err = EBUSY;
  811                         INP_INFO_WUNLOCK(&V_divcbinfo);
  812                         break;
  813                 }
  814                 ip_divert_ptr = NULL;
  815                 err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
  816                 INP_INFO_WUNLOCK(&V_divcbinfo);
  817                 div_destroy();
  818                 EVENTHANDLER_DEREGISTER(maxsockets_change, ip_divert_event_tag);
  819                 break;
  820 #endif /* !VIMAGE */
  821         default:
  822                 err = EOPNOTSUPP;
  823                 break;
  824         }
  825         return err;
  826 }
  827 
  828 static moduledata_t ipdivertmod = {
  829         "ipdivert",
  830         div_modevent,
  831         0
  832 };
  833 
  834 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  835 MODULE_DEPEND(ipdivert, ipfw, 2, 2, 2);
  836 MODULE_VERSION(ipdivert, 1);

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