The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netgraph/ng_rfc1490.c

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    1 /*
    2  * ng_rfc1490.c
    3  */
    4 
    5 /*-
    6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
    7  * All rights reserved.
    8  * 
    9  * Subject to the following obligations and disclaimer of warranty, use and
   10  * redistribution of this software, in source or object code forms, with or
   11  * without modifications are expressly permitted by Whistle Communications;
   12  * provided, however, that:
   13  * 1. Any and all reproductions of the source or object code must include the
   14  *    copyright notice above and the following disclaimer of warranties; and
   15  * 2. No rights are granted, in any manner or form, to use Whistle
   16  *    Communications, Inc. trademarks, including the mark "WHISTLE
   17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   18  *    such appears in the above copyright notice or in the software.
   19  * 
   20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   36  * OF SUCH DAMAGE.
   37  *
   38  * Author: Julian Elischer <julian@freebsd.org>
   39  *
   40  * $FreeBSD: releng/9.2/sys/netgraph/ng_rfc1490.c 220768 2011-04-18 09:12:27Z glebius $
   41  * $Whistle: ng_rfc1490.c,v 1.22 1999/11/01 09:24:52 julian Exp $
   42  */
   43 
   44 /*
   45  * This node does RFC 1490 multiplexing.
   46  *
   47  * NOTE: RFC 1490 is updated by RFC 2427.
   48  */
   49 
   50 #include <sys/param.h>
   51 #include <sys/systm.h>
   52 #include <sys/errno.h>
   53 #include <sys/kernel.h>
   54 #include <sys/malloc.h>
   55 #include <sys/mbuf.h>
   56 #include <sys/errno.h>
   57 #include <sys/socket.h>
   58 
   59 #include <net/if.h>
   60 #include <netinet/in.h>
   61 #include <netinet/if_ether.h>
   62 
   63 #include <netgraph/ng_message.h>
   64 #include <netgraph/netgraph.h>
   65 #include <netgraph/ng_parse.h>
   66 #include <netgraph/ng_rfc1490.h>
   67 
   68 /*
   69  * DEFINITIONS
   70  */
   71 
   72 /* Q.922 stuff -- see RFC 1490 */
   73 #define HDLC_UI         0x03
   74 
   75 #define NLPID_IP        0xCC
   76 #define NLPID_PPP       0xCF
   77 #define NLPID_SNAP      0x80
   78 #define NLPID_Q933      0x08
   79 #define NLPID_CLNP      0x81
   80 #define NLPID_ESIS      0x82
   81 #define NLPID_ISIS      0x83
   82 
   83 #define ERROUT(x)       do { error = (x); goto done; } while (0)
   84 
   85 /* Encapsulation methods we understand */
   86 enum {
   87         NG_RFC1490_ENCAP_IETF_IP = 1,   /* see RFC2427, chapter 7, table 1 */
   88         NG_RFC1490_ENCAP_IETF_SNAP,     /* see RFC2427, chapter 7, table 2 */
   89         NG_RFC1490_ENCAP_CISCO,         /* Cisco's proprietary encapsulation */
   90 };
   91 
   92 struct ng_rfc1490_encap_t {
   93         u_int8_t        method;
   94         const char      *name;
   95 };
   96 
   97 static const struct ng_rfc1490_encap_t ng_rfc1490_encaps[] = {
   98         { NG_RFC1490_ENCAP_IETF_IP,     "ietf-ip" },
   99         { NG_RFC1490_ENCAP_IETF_SNAP,   "ietf-snap" },
  100         { NG_RFC1490_ENCAP_CISCO,       "cisco" },
  101         { 0, NULL},
  102 };
  103 
  104 /* Node private data */
  105 struct ng_rfc1490_private {
  106         hook_p  downlink;
  107         hook_p  ppp;
  108         hook_p  inet;
  109         hook_p  ethernet;
  110         const struct ng_rfc1490_encap_t *enc;
  111 };
  112 typedef struct ng_rfc1490_private *priv_p;
  113 
  114 /* Netgraph node methods */
  115 static ng_constructor_t ng_rfc1490_constructor;
  116 static ng_rcvmsg_t      ng_rfc1490_rcvmsg;
  117 static ng_shutdown_t    ng_rfc1490_shutdown;
  118 static ng_newhook_t     ng_rfc1490_newhook;
  119 static ng_rcvdata_t     ng_rfc1490_rcvdata;
  120 static ng_disconnect_t  ng_rfc1490_disconnect;
  121 
  122 /* List of commands and how to convert arguments to/from ASCII */
  123 static const struct ng_cmdlist ng_rfc1490_cmds[] = {
  124         {
  125           NGM_RFC1490_COOKIE,
  126           NGM_RFC1490_SET_ENCAP,
  127           "setencap",
  128           &ng_parse_string_type,
  129           NULL
  130         },
  131         {
  132           NGM_RFC1490_COOKIE,
  133           NGM_RFC1490_GET_ENCAP,
  134           "getencap",
  135           NULL,
  136           &ng_parse_string_type
  137         },
  138         { 0 }
  139 };
  140 
  141 /* Node type descriptor */
  142 static struct ng_type typestruct = {
  143         .version =      NG_ABI_VERSION,
  144         .name =         NG_RFC1490_NODE_TYPE,
  145         .constructor =  ng_rfc1490_constructor,
  146         .rcvmsg =       ng_rfc1490_rcvmsg,
  147         .shutdown =     ng_rfc1490_shutdown,
  148         .newhook =      ng_rfc1490_newhook,
  149         .rcvdata =      ng_rfc1490_rcvdata,
  150         .disconnect =   ng_rfc1490_disconnect,
  151         .cmdlist =      ng_rfc1490_cmds,
  152 };
  153 NETGRAPH_INIT(rfc1490, &typestruct);
  154 
  155 /************************************************************************
  156                         NETGRAPH NODE STUFF
  157  ************************************************************************/
  158 
  159 /*
  160  * Node constructor
  161  */
  162 static int
  163 ng_rfc1490_constructor(node_p node)
  164 {
  165         priv_p priv;
  166 
  167         /* Allocate private structure */
  168         priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
  169 
  170         /* Initialize to default encapsulation method - ietf-ip */
  171         priv->enc = ng_rfc1490_encaps;
  172 
  173         NG_NODE_SET_PRIVATE(node, priv);
  174 
  175         /* Done */
  176         return (0);
  177 }
  178 
  179 /*
  180  * Give our ok for a hook to be added
  181  */
  182 static int
  183 ng_rfc1490_newhook(node_p node, hook_p hook, const char *name)
  184 {
  185         const priv_p priv = NG_NODE_PRIVATE(node);
  186 
  187         if (!strcmp(name, NG_RFC1490_HOOK_DOWNSTREAM)) {
  188                 if (priv->downlink)
  189                         return (EISCONN);
  190                 priv->downlink = hook;
  191         } else if (!strcmp(name, NG_RFC1490_HOOK_PPP)) {
  192                 if (priv->ppp)
  193                         return (EISCONN);
  194                 priv->ppp = hook;
  195         } else if (!strcmp(name, NG_RFC1490_HOOK_INET)) {
  196                 if (priv->inet)
  197                         return (EISCONN);
  198                 priv->inet = hook;
  199         } else if (!strcmp(name, NG_RFC1490_HOOK_ETHERNET)) {
  200                 if (priv->ethernet)
  201                         return (EISCONN);
  202                 priv->ethernet = hook;
  203         } else
  204                 return (EINVAL);
  205         return (0);
  206 }
  207 
  208 /*
  209  * Receive a control message.
  210  */
  211 static int
  212 ng_rfc1490_rcvmsg(node_p node, item_p item, hook_p lasthook)
  213 {
  214         const priv_p priv = NG_NODE_PRIVATE(node);
  215         struct ng_mesg *msg;
  216         struct ng_mesg *resp = NULL;
  217         int error = 0;
  218 
  219         NGI_GET_MSG(item, msg);
  220 
  221         if (msg->header.typecookie == NGM_RFC1490_COOKIE) {
  222                 switch (msg->header.cmd) {
  223                 case NGM_RFC1490_SET_ENCAP:
  224                 {
  225                         const struct ng_rfc1490_encap_t *enc;
  226                         char *s;
  227                         size_t len;
  228 
  229                         if (msg->header.arglen == 0)
  230                                 ERROUT(EINVAL);
  231 
  232                         s = (char *)msg->data;
  233                         len = msg->header.arglen - 1;
  234 
  235                         /* Search for matching encapsulation method */
  236                         for (enc = ng_rfc1490_encaps; enc->method != 0; enc++ )
  237                                 if ((strlen(enc->name) == len) &&
  238                                     !strncmp(enc->name, s, len))
  239                                         break;  /* found */
  240 
  241                         if (enc->method != 0)
  242                                 priv->enc = enc;
  243                         else
  244                                 error = EINVAL;
  245                         break;
  246                 }
  247                 case NGM_RFC1490_GET_ENCAP:
  248 
  249                         NG_MKRESPONSE(resp, msg, strlen(priv->enc->name) + 1, M_NOWAIT);
  250                         if (resp == NULL)
  251                                 ERROUT(ENOMEM);
  252 
  253                         strlcpy((char *)resp->data, priv->enc->name,
  254                             strlen(priv->enc->name) + 1);
  255                         break;
  256 
  257                 default:
  258                         error = EINVAL;
  259                         break;
  260                 }
  261         } else
  262                 error = EINVAL;
  263 
  264 done:
  265         NG_RESPOND_MSG(error, node, item, resp);
  266         NG_FREE_MSG(msg);
  267         return (error);
  268 }
  269 
  270 /*
  271  * Receive data on a hook and encapsulate according to RFC 1490.
  272  * Only those nodes marked (*) are supported by this routine so far.
  273  *
  274  *                            Q.922 control
  275  *                                 |
  276  *                                 |
  277  *            ---------------------------------------------------------------------
  278  *            | 0x03                                     |                        |
  279  *           UI                                       I Frame                   Cisco
  280  *            |                                          |                  Encapsulation
  281  *      ---------------------------------         --------------                  |
  282  *      | 0x08  | 0x81  |0xCC   |0xCF   | 0x00    |..01....    |..10....   --------------
  283  *      |       |       |       |       | 0x80    |            |           |0x800       |
  284  *     Q.933   CLNP    IP(*)   PPP(*)  SNAP     ISO 8208    ISO 8208       |            |
  285  *      |                    (rfc1973)  |       Modulo 8    Modulo 128     IP(*)     Others
  286  *      |                               |
  287  *      --------------------           OUI
  288  *      |                  |            |
  289  *     L2 ID              L3 ID      -------------------------
  290  *      |               User         |00-80-C2               |00-00-00
  291  *      |               specified    |                       |
  292  *      |               0x70        PID                     Ethertype
  293  *      |                            |                       |
  294  *      -------------------        -----------------...     ----------
  295  *      |0x51 |0x4E |     |0x4C    |0x7      |0xB  |        |0x806   |
  296  *      |     |     |     |        |         |     |        |        |
  297  *     7776  Q.922 Others 802.2   802.3(*)  802.6 Others    IP(*)   Others
  298  *
  299  *
  300  */
  301 
  302 #define MAX_ENCAPS_HDR  8
  303 #define OUICMP(P,A,B,C) ((P)[0]==(A) && (P)[1]==(B) && (P)[2]==(C))
  304 
  305 static int
  306 ng_rfc1490_rcvdata(hook_p hook, item_p item)
  307 {
  308         const node_p node = NG_HOOK_NODE(hook);
  309         const priv_p priv = NG_NODE_PRIVATE(node);
  310         int error = 0;
  311         struct mbuf *m;
  312 
  313         NGI_GET_M(item, m);
  314         if (hook == priv->downlink) {
  315                 const u_char *start;
  316                 const u_char *ptr;
  317 
  318                 if (m->m_len < MAX_ENCAPS_HDR
  319                     && !(m = m_pullup(m, MAX_ENCAPS_HDR)))
  320                         ERROUT(ENOBUFS);
  321                 ptr = start = mtod(m, const u_char *);
  322 
  323                 if (priv->enc->method == NG_RFC1490_ENCAP_CISCO)
  324                         goto switch_on_etype;
  325 
  326                 /* Must be UI frame */
  327                 if (*ptr++ != HDLC_UI)
  328                         ERROUT(0);
  329 
  330                 /* Eat optional zero pad byte */
  331                 if (*ptr == 0x00)
  332                         ptr++;
  333 
  334                 /* Multiplex on NLPID */
  335                 switch (*ptr++) {
  336                 case NLPID_SNAP:
  337                         if (OUICMP(ptr, 0, 0, 0)) {     /* It's an ethertype */
  338                                 u_int16_t etype;
  339 
  340                                 ptr += 3;
  341 switch_on_etype:                etype = ntohs(*((const u_int16_t *)ptr));
  342                                 ptr += 2;
  343                                 m_adj(m, ptr - start);
  344                                 switch (etype) {
  345                                 case ETHERTYPE_IP:
  346                                         NG_FWD_NEW_DATA(error, item,
  347                                             priv->inet, m);
  348                                         break;
  349                                 case ETHERTYPE_ARP:
  350                                 case ETHERTYPE_REVARP:
  351                                 default:
  352                                         ERROUT(0);
  353                                 }
  354                         } else if (OUICMP(ptr, 0x00, 0x80, 0xc2)) {
  355                                 /* 802.1 bridging */
  356                                 ptr += 3;
  357                                 if (*ptr++ != 0x00)
  358                                         ERROUT(0);      /* unknown PID octet 0 */
  359                                 if (*ptr++ != 0x07)
  360                                         ERROUT(0);      /* not FCS-less 802.3 */
  361                                 m_adj(m, ptr - start);
  362                                 NG_FWD_NEW_DATA(error, item, priv->ethernet, m);
  363                         } else  /* Other weird stuff... */
  364                                 ERROUT(0);
  365                         break;
  366                 case NLPID_IP:
  367                         m_adj(m, ptr - start);
  368                         NG_FWD_NEW_DATA(error, item, priv->inet, m);
  369                         break;
  370                 case NLPID_PPP:
  371                         m_adj(m, ptr - start);
  372                         NG_FWD_NEW_DATA(error, item, priv->ppp, m);
  373                         break;
  374                 case NLPID_Q933:
  375                 case NLPID_CLNP:
  376                 case NLPID_ESIS:
  377                 case NLPID_ISIS:
  378                         ERROUT(0);
  379                 default:        /* Try PPP (see RFC 1973) */
  380                         ptr--;  /* NLPID becomes PPP proto */
  381                         if ((*ptr & 0x01) == 0x01)
  382                                 ERROUT(0);
  383                         m_adj(m, ptr - start);
  384                         NG_FWD_NEW_DATA(error, item, priv->ppp, m);
  385                         break;
  386                 }
  387         } else if (hook == priv->ppp) {
  388                 M_PREPEND(m, 2, M_DONTWAIT);    /* Prepend PPP NLPID */
  389                 if (!m)
  390                         ERROUT(ENOBUFS);
  391                 mtod(m, u_char *)[0] = HDLC_UI;
  392                 mtod(m, u_char *)[1] = NLPID_PPP;
  393                 NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  394         } else if (hook == priv->inet) {
  395                 switch (priv->enc->method) {
  396                 case NG_RFC1490_ENCAP_IETF_IP:
  397                         M_PREPEND(m, 2, M_DONTWAIT);    /* Prepend IP NLPID */
  398                         if (!m)
  399                                 ERROUT(ENOBUFS);
  400                         mtod(m, u_char *)[0] = HDLC_UI;
  401                         mtod(m, u_char *)[1] = NLPID_IP;
  402                         break;
  403                 case NG_RFC1490_ENCAP_IETF_SNAP:
  404                         /*
  405                          *  According to RFC2427 frame should begin with
  406                          *  HDLC_UI  PAD  NLIPID  OUI      PID
  407                          *  03      00   80      00 00 00  08 00
  408                          */
  409                         M_PREPEND(m, 8, M_DONTWAIT);
  410                         if (!m)
  411                                 ERROUT(ENOBUFS);
  412                         mtod(m, u_char *)[0] = HDLC_UI;
  413                         mtod(m, u_char *)[1] = 0x00;                    /* PAD */
  414                         mtod(m, u_char *)[2] = NLPID_SNAP;
  415                         bzero((char *)(mtod(m, u_char *) + 3), 3);      /* OUI 0-0-0 */
  416                         *((u_int16_t *)mtod(m, u_int16_t *) + 6/sizeof(u_int16_t))
  417                             = htons(ETHERTYPE_IP);  /* PID */
  418                         break;
  419                 case NG_RFC1490_ENCAP_CISCO:
  420                         M_PREPEND(m, 2, M_DONTWAIT);    /* Prepend IP ethertype */
  421                         if (!m)
  422                                 ERROUT(ENOBUFS);
  423                         *((u_int16_t *)mtod(m, u_int16_t *)) = htons(ETHERTYPE_IP);
  424                         break;
  425                 }
  426                 NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  427         } else if (hook == priv->ethernet) {
  428                 M_PREPEND(m, 8, M_DONTWAIT);    /* Prepend NLPID, OUI, PID */
  429                 if (!m)
  430                         ERROUT(ENOBUFS);
  431                 mtod(m, u_char *)[0] = HDLC_UI;
  432                 mtod(m, u_char *)[1] = 0x00;            /* pad */
  433                 mtod(m, u_char *)[2] = NLPID_SNAP;
  434                 mtod(m, u_char *)[3] = 0x00;            /* OUI */
  435                 mtod(m, u_char *)[4] = 0x80;
  436                 mtod(m, u_char *)[5] = 0xc2;
  437                 mtod(m, u_char *)[6] = 0x00;            /* PID */
  438                 mtod(m, u_char *)[7] = 0x07;
  439                 NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  440         } else
  441                 panic("%s", __func__);
  442 
  443 done:
  444         if (item)
  445                 NG_FREE_ITEM(item);
  446         NG_FREE_M(m);
  447         return (error);
  448 }
  449 
  450 /*
  451  * Nuke node
  452  */
  453 static int
  454 ng_rfc1490_shutdown(node_p node)
  455 {
  456         const priv_p priv = NG_NODE_PRIVATE(node);
  457 
  458         /* Take down netgraph node */
  459         bzero(priv, sizeof(*priv));
  460         free(priv, M_NETGRAPH);
  461         NG_NODE_SET_PRIVATE(node, NULL);
  462         NG_NODE_UNREF(node);            /* let the node escape */
  463         return (0);
  464 }
  465 
  466 /*
  467  * Hook disconnection
  468  */
  469 static int
  470 ng_rfc1490_disconnect(hook_p hook)
  471 {
  472         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  473 
  474         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
  475         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
  476                 ng_rmnode_self(NG_HOOK_NODE(hook));
  477         else if (hook == priv->downlink)
  478                 priv->downlink = NULL;
  479         else if (hook == priv->inet)
  480                 priv->inet = NULL;
  481         else if (hook == priv->ppp)
  482                 priv->ppp = NULL;
  483         else if (hook == priv->ethernet)
  484                 priv->ethernet = NULL;
  485         else
  486                 panic("%s", __func__);
  487         return (0);
  488 }
  489 

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