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

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    1 /*
    2  * Copyright (c) 1984, 1985, 1986, 1987, 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. All advertising materials mentioning features or use of this software
   14  *    must display the following acknowledgement:
   15  *      This product includes software developed by the University of
   16  *      California, Berkeley and its contributors.
   17  * 4. Neither the name of the University nor the names of its contributors
   18  *    may be used to endorse or promote products derived from this software
   19  *    without specific prior written permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31  * SUCH DAMAGE.
   32  *
   33  *      @(#)ns_input.c  8.1 (Berkeley) 6/10/93
   34  * $FreeBSD: releng/5.0/sys/netns/ns_input.c 93818 2002-04-04 21:03:38Z jhb $
   35  */
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/malloc.h>
   40 #include <sys/mbuf.h>
   41 #include <sys/domain.h>
   42 #include <sys/protosw.h>
   43 #include <sys/socket.h>
   44 #include <sys/socketvar.h>
   45 #include <sys/errno.h>
   46 #include <sys/time.h>
   47 #include <sys/kernel.h>
   48 
   49 #include <net/if.h>
   50 #include <net/route.h>
   51 #include <net/raw_cb.h>
   52 #include <net/netisr.h>
   53 #include <net/intrq.h>
   54 
   55 #include <netns/ns.h>
   56 #include <netns/ns_if.h>
   57 #include <netns/ns_pcb.h>
   58 #include <netns/idp.h>
   59 #include <netns/idp_var.h>
   60 #include <netns/ns_error.h>
   61 
   62 /*
   63  * NS initialization.
   64  */
   65 union ns_host   ns_thishost;
   66 union ns_host   ns_zerohost;
   67 union ns_host   ns_broadhost;
   68 union ns_net    ns_zeronet;
   69 union ns_net    ns_broadnet;
   70 struct sockaddr_ns ns_netmask, ns_hostmask;
   71 
   72 static u_short allones[] = {-1, -1, -1};
   73 
   74 struct nspcb nspcb;
   75 struct nspcb nsrawpcb;
   76 
   77 int     nsqmaxlen = IFQ_MAXLEN;
   78 
   79 int     idpcksum = 1;
   80 long    ns_pexseq;
   81 
   82 ns_init()
   83 {
   84         extern struct timeval time;
   85 
   86         ns_broadhost = * (union ns_host *) allones;
   87         ns_broadnet = * (union ns_net *) allones;
   88         nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
   89         nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
   90         nsintrq.ifq_maxlen = nsqmaxlen;
   91         mtx_init(&nsintrq.ifq_mtx, "ns_inq", NULL, MTX_DEF);
   92         nsintrq_present = 1;
   93         ns_pexseq = time.tv_usec;
   94         ns_netmask.sns_len = 6;
   95         ns_netmask.sns_addr.x_net = ns_broadnet;
   96         ns_hostmask.sns_len = 12;
   97         ns_hostmask.sns_addr.x_net = ns_broadnet;
   98         ns_hostmask.sns_addr.x_host = ns_broadhost;
   99         register_netisr(NETISR_NS, nsintr);
  100 }
  101 
  102 /*
  103  * Idp input routine.  Pass to next level.
  104  */
  105 int nsintr_getpck = 0;
  106 int nsintr_swtch = 0;
  107 void
  108 nsintr(void)
  109 {
  110         register struct idp *idp;
  111         register struct mbuf *m;
  112         register struct nspcb *nsp;
  113         register int i;
  114         int len, s, error;
  115         char oddpacketp;
  116 
  117 next:
  118         /*
  119          * Get next datagram off input queue and get IDP header
  120          * in first mbuf.
  121          */
  122         s = splimp();
  123         IF_DEQUEUE(&nsintrq, m);
  124         splx(s);
  125         nsintr_getpck++;
  126         if (m == 0)
  127                 return;
  128         if ((m->m_flags & M_EXT || m->m_len < sizeof (struct idp)) &&
  129             (m = m_pullup(m, sizeof (struct idp))) == 0) {
  130                 idpstat.idps_toosmall++;
  131                 goto next;
  132         }
  133 
  134         /*
  135          * Give any raw listeners a crack at the packet
  136          */
  137         for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
  138                 struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
  139                 if (m1) idp_input(m1, nsp);
  140         }
  141 
  142         idp = mtod(m, struct idp *);
  143         len = ntohs(idp->idp_len);
  144         if (oddpacketp = len & 1) {
  145                 len++;          /* If this packet is of odd length,
  146                                    preserve garbage byte for checksum */
  147         }
  148 
  149         /*
  150          * Check that the amount of data in the buffers
  151          * is as at least much as the IDP header would have us expect.
  152          * Trim mbufs if longer than we expect.
  153          * Drop packet if shorter than we expect.
  154          */
  155         if (m->m_pkthdr.len < len) {
  156                 idpstat.idps_tooshort++;
  157                 goto bad;
  158         }
  159         if (m->m_pkthdr.len > len) {
  160                 if (m->m_len == m->m_pkthdr.len) {
  161                         m->m_len = len;
  162                         m->m_pkthdr.len = len;
  163                 } else
  164                         m_adj(m, len - m->m_pkthdr.len);
  165         }
  166         if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
  167                 idp->idp_sum = 0;
  168                 if (i != (idp->idp_sum = ns_cksum(m, len))) {
  169                         idpstat.idps_badsum++;
  170                         idp->idp_sum = i;
  171                         if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
  172                                 error = NS_ERR_BADSUM;
  173                         else
  174                                 error = NS_ERR_BADSUM_T;
  175                         ns_error(m, error, 0);
  176                         goto next;
  177                 }
  178         }
  179         /*
  180          * Is this a directed broadcast?
  181          */
  182         if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
  183                 if ((!ns_neteq(idp->idp_dna, idp->idp_sna)) &&
  184                     (!ns_neteqnn(idp->idp_dna.x_net, ns_broadnet)) &&
  185                     (!ns_neteqnn(idp->idp_sna.x_net, ns_zeronet)) &&
  186                     (!ns_neteqnn(idp->idp_dna.x_net, ns_zeronet)) ) {
  187                         /*
  188                          * Look to see if I need to eat this packet.
  189                          * Algorithm is to forward all young packets
  190                          * and prematurely age any packets which will
  191                          * by physically broadcasted.
  192                          * Any very old packets eaten without forwarding
  193                          * would die anyway.
  194                          *
  195                          * Suggestion of Bill Nesheim, Cornell U.
  196                          */
  197                         if (idp->idp_tc < NS_MAXHOPS) {
  198                                 idp_forward(m);
  199                                 goto next;
  200                         }
  201                 }
  202         /*
  203          * Is this our packet? If not, forward.
  204          */
  205         } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
  206                 idp_forward(m);
  207                 goto next;
  208         }
  209         /*
  210          * Locate pcb for datagram.
  211          */
  212         nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
  213         /*
  214          * Switch out to protocol's input routine.
  215          */
  216         nsintr_swtch++;
  217         if (nsp) {
  218                 if (oddpacketp) {
  219                         m_adj(m, -1);
  220                 }
  221                 if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
  222                         switch (idp->idp_pt) {
  223 
  224                             case NSPROTO_SPP:
  225                                     spp_input(m, nsp);
  226                                     goto next;
  227 
  228                             case NSPROTO_ERROR:
  229                                     ns_err_input(m);
  230                                     goto next;
  231                         }
  232                 idp_input(m, nsp);
  233         } else {
  234                 ns_error(m, NS_ERR_NOSOCK, 0);
  235         }
  236         goto next;
  237 
  238 bad:
  239         m_freem(m);
  240         goto next;
  241 }
  242 
  243 u_char nsctlerrmap[PRC_NCMDS] = {
  244         ECONNABORTED,   ECONNABORTED,   0,              0,
  245         0,              0,              EHOSTDOWN,      EHOSTUNREACH,
  246         ENETUNREACH,    EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
  247         EMSGSIZE,       0,              0,              0,
  248         0,              0,              0,              0
  249 };
  250 
  251 int idp_donosocks = 1;
  252 
  253 idp_ctlinput(cmd, arg)
  254         int cmd;
  255         caddr_t arg;
  256 {
  257         struct ns_addr *ns;
  258         struct nspcb *nsp;
  259         struct ns_errp *errp;
  260         int idp_abort();
  261         extern struct nspcb *idp_drop();
  262         int type;
  263 
  264         if (cmd < 0 || cmd > PRC_NCMDS)
  265                 return;
  266         if (nsctlerrmap[cmd] == 0)
  267                 return;         /* XXX */
  268         type = NS_ERR_UNREACH_HOST;
  269         switch (cmd) {
  270                 struct sockaddr_ns *sns;
  271 
  272         case PRC_IFDOWN:
  273         case PRC_HOSTDEAD:
  274         case PRC_HOSTUNREACH:
  275                 sns = (struct sockaddr_ns *)arg;
  276                 if (sns->sns_family != AF_NS)
  277                         return;
  278                 ns = &sns->sns_addr;
  279                 break;
  280 
  281         default:
  282                 errp = (struct ns_errp *)arg;
  283                 ns = &errp->ns_err_idp.idp_dna;
  284                 type = errp->ns_err_num;
  285                 type = ntohs((u_short)type);
  286         }
  287         switch (type) {
  288 
  289         case NS_ERR_UNREACH_HOST:
  290                 ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
  291                 break;
  292 
  293         case NS_ERR_NOSOCK:
  294                 nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
  295                         NS_WILDCARD);
  296                 if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
  297                         (void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
  298         }
  299 }
  300 
  301 int     idpprintfs = 0;
  302 int     idpforwarding = 1;
  303 /*
  304  * Forward a packet.  If some error occurs return the sender
  305  * an error packet.  Note we can't always generate a meaningful
  306  * error message because the NS errors don't have a large enough repetoire
  307  * of codes and types.
  308  */
  309 struct route idp_droute;
  310 struct route idp_sroute;
  311 
  312 idp_forward(m)
  313 struct mbuf *m;
  314 {
  315         register struct idp *idp = mtod(m, struct idp *);
  316         register int error, type, code;
  317         struct mbuf *mcopy = NULL;
  318         int agedelta = 1;
  319         int flags = NS_FORWARDING;
  320         int ok_there = 0;
  321         int ok_back = 0;
  322 
  323         if (idpprintfs) {
  324                 printf("forward: src ");
  325                 ns_printhost(&idp->idp_sna);
  326                 printf(", dst ");
  327                 ns_printhost(&idp->idp_dna);
  328                 printf("hop count %d\n", idp->idp_tc);
  329         }
  330         if (idpforwarding == 0) {
  331                 /* can't tell difference between net and host */
  332                 type = NS_ERR_UNREACH_HOST, code = 0;
  333                 goto senderror;
  334         }
  335         idp->idp_tc++;
  336         if (idp->idp_tc > NS_MAXHOPS) {
  337                 type = NS_ERR_TOO_OLD, code = 0;
  338                 goto senderror;
  339         }
  340         /*
  341          * Save at most 42 bytes of the packet in case
  342          * we need to generate an NS error message to the src.
  343          */
  344         mcopy = m_copy(m, 0, imin((int)ntohs(idp->idp_len), 42));
  345 
  346         if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
  347                 type = NS_ERR_UNREACH_HOST, code = 0;
  348                 goto senderror;
  349         }
  350         /*
  351          * Here we think about  forwarding  broadcast packets,
  352          * so we try to insure that it doesn't go back out
  353          * on the interface it came in on.  Also, if we
  354          * are going to physically broadcast this, let us
  355          * age the packet so we can eat it safely the second time around.
  356          */
  357         if (idp->idp_dna.x_host.c_host[0] & 0x1) {
  358                 struct ns_ifaddr *ia = ns_iaonnetof(&idp->idp_dna);
  359                 struct ifnet *ifp;
  360                 if (ia) {
  361                         /* I'm gonna hafta eat this packet */
  362                         agedelta += NS_MAXHOPS - idp->idp_tc;
  363                         idp->idp_tc = NS_MAXHOPS;
  364                 }
  365                 if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
  366                         /* error = ENETUNREACH; He'll never get it! */
  367                         m_freem(m);
  368                         goto cleanup;
  369                 }
  370                 if (idp_droute.ro_rt &&
  371                     (ifp=idp_droute.ro_rt->rt_ifp) &&
  372                     idp_sroute.ro_rt &&
  373                     (ifp!=idp_sroute.ro_rt->rt_ifp)) {
  374                         flags |= NS_ALLOWBROADCAST;
  375                 } else {
  376                         type = NS_ERR_UNREACH_HOST, code = 0;
  377                         goto senderror;
  378                 }
  379         }
  380         /* need to adjust checksum */
  381         if (idp->idp_sum!=0xffff) {
  382                 union bytes {
  383                         u_char c[4];
  384                         u_short s[2];
  385                         long l;
  386                 } x;
  387                 register int shift;
  388                 x.l = 0; x.c[0] = agedelta;
  389                 shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
  390                 x.l = idp->idp_sum + (x.s[0] << shift);
  391                 x.l = x.s[0] + x.s[1];
  392                 x.l = x.s[0] + x.s[1];
  393                 if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
  394         }
  395         if ((error = ns_output(m, &idp_droute, flags)) &&
  396             (mcopy!=NULL)) {
  397                 idp = mtod(mcopy, struct idp *);
  398                 type = NS_ERR_UNSPEC_T, code = 0;
  399                 switch (error) {
  400 
  401                 case ENETUNREACH:
  402                 case EHOSTDOWN:
  403                 case EHOSTUNREACH:
  404                 case ENETDOWN:
  405                 case EPERM:
  406                         type = NS_ERR_UNREACH_HOST;
  407                         break;
  408 
  409                 case EMSGSIZE:
  410                         type = NS_ERR_TOO_BIG;
  411                         code = 576; /* too hard to figure out mtu here */
  412                         break;
  413 
  414                 case ENOBUFS:
  415                         type = NS_ERR_UNSPEC_T;
  416                         break;
  417                 }
  418                 mcopy = NULL;
  419         senderror:
  420                 ns_error(m, type, code);
  421         }
  422 cleanup:
  423         if (ok_there)
  424                 idp_undo_route(&idp_droute);
  425         if (ok_back)
  426                 idp_undo_route(&idp_sroute);
  427         if (mcopy != NULL)
  428                 m_freem(mcopy);
  429 }
  430 
  431 idp_do_route(src, ro)
  432 struct ns_addr *src;
  433 struct route *ro;
  434 {
  435 
  436         struct sockaddr_ns *dst;
  437 
  438         bzero((caddr_t)ro, sizeof (*ro));
  439         dst = (struct sockaddr_ns *)&ro->ro_dst;
  440 
  441         dst->sns_len = sizeof(*dst);
  442         dst->sns_family = AF_NS;
  443         dst->sns_addr = *src;
  444         dst->sns_addr.x_port = 0;
  445         rtalloc(ro);
  446         if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) {
  447                 return (0);
  448         }
  449         ro->ro_rt->rt_use++;
  450         return (1);
  451 }
  452 
  453 idp_undo_route(ro)
  454 register struct route *ro;
  455 {
  456         if (ro->ro_rt) {RTFREE(ro->ro_rt);}
  457 }
  458 
  459 ns_watch_output(m, ifp)
  460 struct mbuf *m;
  461 struct ifnet *ifp;
  462 {
  463         register struct nspcb *nsp;
  464         register struct ifaddr *ifa;
  465         /*
  466          * Give any raw listeners a crack at the packet
  467          */
  468         for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
  469                 struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL);
  470                 if (m0) {
  471                         register struct idp *idp;
  472 
  473                         M_PREPEND(m0, sizeof (*idp), M_DONTWAIT);
  474                         if (m0 == NULL)
  475                                 continue;
  476                         idp = mtod(m0, struct idp *);
  477                         idp->idp_sna.x_net = ns_zeronet;
  478                         idp->idp_sna.x_host = ns_thishost;
  479                         if (ifp && (ifp->if_flags & IFF_POINTOPOINT))
  480                             for(ifa = ifp->if_addrlist; ifa;
  481                                                 ifa = ifa->ifa_next) {
  482                                 if (ifa->ifa_addr->sa_family==AF_NS) {
  483                                     idp->idp_sna = IA_SNS(ifa)->sns_addr;
  484                                     break;
  485                                 }
  486                             }
  487                         idp->idp_len = ntohl(m0->m_pkthdr.len);
  488                         idp_input(m0, nsp);
  489                 }
  490         }
  491 }

Cache object: afbf8ce6384c3535d7988326c8bbc8bd


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