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

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    1 /*
    2  * ng_socket.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  * $FreeBSD$
   41  * $Whistle: ng_socket.c,v 1.28 1999/11/01 09:24:52 julian Exp $
   42  */
   43 
   44 /*
   45  * Netgraph socket nodes
   46  *
   47  * There are two types of netgraph sockets, control and data.
   48  * Control sockets have a netgraph node, but data sockets are
   49  * parasitic on control sockets, and have no node of their own.
   50  */
   51 
   52 #include <sys/param.h>
   53 #include <sys/domain.h>
   54 #include <sys/kernel.h>
   55 #include <sys/linker.h>
   56 #include <sys/lock.h>
   57 #include <sys/malloc.h>
   58 #include <sys/mbuf.h>
   59 #include <sys/mutex.h>
   60 #include <sys/priv.h>
   61 #include <sys/protosw.h>
   62 #include <sys/queue.h>
   63 #include <sys/socket.h>
   64 #include <sys/socketvar.h>
   65 #include <sys/syscallsubr.h>
   66 #include <sys/sysctl.h>
   67 #ifdef NOTYET
   68 #include <sys/vnode.h>
   69 #endif
   70 #include <netgraph/ng_message.h>
   71 #include <netgraph/netgraph.h>
   72 #include <netgraph/ng_socketvar.h>
   73 #include <netgraph/ng_socket.h>
   74 
   75 #ifdef NG_SEPARATE_MALLOC
   76 MALLOC_DEFINE(M_NETGRAPH_PATH, "netgraph_path", "netgraph path info ");
   77 MALLOC_DEFINE(M_NETGRAPH_SOCK, "netgraph_sock", "netgraph socket info ");
   78 #else
   79 #define M_NETGRAPH_PATH M_NETGRAPH
   80 #define M_NETGRAPH_SOCK M_NETGRAPH
   81 #endif
   82 
   83 /*
   84  * It's Ascii-art time!
   85  *   +-------------+   +-------------+
   86  *   |socket  (ctl)|   |socket (data)|
   87  *   +-------------+   +-------------+
   88  *          ^                 ^
   89  *          |                 |
   90  *          v                 v
   91  *    +-----------+     +-----------+
   92  *    |pcb   (ctl)|     |pcb  (data)|
   93  *    +-----------+     +-----------+
   94  *          ^                 ^
   95  *          |                 |
   96  *          v                 v
   97  *      +--------------------------+
   98  *      |   Socket type private    |
   99  *      |       data               |
  100  *      +--------------------------+
  101  *                   ^
  102  *                   |
  103  *                   v
  104  *           +----------------+
  105  *           | struct ng_node |
  106  *           +----------------+
  107  */
  108 
  109 /* Netgraph node methods */
  110 static ng_constructor_t ngs_constructor;
  111 static ng_rcvmsg_t      ngs_rcvmsg;
  112 static ng_shutdown_t    ngs_shutdown;
  113 static ng_newhook_t     ngs_newhook;
  114 static ng_connect_t     ngs_connect;
  115 static ng_rcvdata_t     ngs_rcvdata;
  116 static ng_disconnect_t  ngs_disconnect;
  117 
  118 /* Internal methods */
  119 static int      ng_attach_data(struct socket *so);
  120 static int      ng_attach_cntl(struct socket *so);
  121 static int      ng_attach_common(struct socket *so, int type);
  122 static void     ng_detach_common(struct ngpcb *pcbp, int type);
  123 static void     ng_socket_free_priv(struct ngsock *priv);
  124 #ifdef NOTYET
  125 static int      ng_internalize(struct mbuf *m, struct thread *p);
  126 #endif
  127 static int      ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp);
  128 static int      ng_bind(struct sockaddr *nam, struct ngpcb *pcbp);
  129 
  130 static int      ngs_mod_event(module_t mod, int event, void *data);
  131 static void     ng_socket_item_applied(void *context, int error);
  132 
  133 /* Netgraph type descriptor */
  134 static struct ng_type typestruct = {
  135         .version =      NG_ABI_VERSION,
  136         .name =         NG_SOCKET_NODE_TYPE,
  137         .mod_event =    ngs_mod_event,
  138         .constructor =  ngs_constructor,
  139         .rcvmsg =       ngs_rcvmsg,
  140         .shutdown =     ngs_shutdown,
  141         .newhook =      ngs_newhook,
  142         .connect =      ngs_connect,
  143         .rcvdata =      ngs_rcvdata,
  144         .disconnect =   ngs_disconnect,
  145 };
  146 NETGRAPH_INIT_ORDERED(socket, &typestruct, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
  147 
  148 /* Buffer space */
  149 static u_long ngpdg_sendspace = 20 * 1024;      /* really max datagram size */
  150 SYSCTL_INT(_net_graph, OID_AUTO, maxdgram, CTLFLAG_RW,
  151     &ngpdg_sendspace , 0, "Maximum outgoing Netgraph datagram size");
  152 static u_long ngpdg_recvspace = 20 * 1024;
  153 SYSCTL_INT(_net_graph, OID_AUTO, recvspace, CTLFLAG_RW,
  154     &ngpdg_recvspace , 0, "Maximum space for incoming Netgraph datagrams");
  155 
  156 #define sotongpcb(so) ((struct ngpcb *)(so)->so_pcb)
  157 
  158 /* If getting unexplained errors returned, set this to "kdb_enter("X"); */
  159 #ifndef TRAP_ERROR
  160 #define TRAP_ERROR
  161 #endif
  162 
  163 /***************************************************************
  164         Control sockets
  165 ***************************************************************/
  166 
  167 static int
  168 ngc_attach(struct socket *so, int proto, struct thread *td)
  169 {
  170         struct ngpcb *const pcbp = sotongpcb(so);
  171         int error;
  172 
  173         error = priv_check(td, PRIV_NETGRAPH_CONTROL);
  174         if (error)
  175                 return (error);
  176         if (pcbp != NULL)
  177                 return (EISCONN);
  178         return (ng_attach_cntl(so));
  179 }
  180 
  181 static void
  182 ngc_detach(struct socket *so)
  183 {
  184         struct ngpcb *const pcbp = sotongpcb(so);
  185 
  186         KASSERT(pcbp != NULL, ("ngc_detach: pcbp == NULL"));
  187         ng_detach_common(pcbp, NG_CONTROL);
  188 }
  189 
  190 static int
  191 ngc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
  192          struct mbuf *control, struct thread *td)
  193 {
  194         struct ngpcb *const pcbp = sotongpcb(so);
  195         struct ngsock *const priv = NG_NODE_PRIVATE(pcbp->sockdata->node);
  196         struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
  197         struct ng_mesg *msg;
  198         struct mbuf *m0;
  199         item_p item;
  200         char *path = NULL;
  201         int len, error = 0;
  202         struct ng_apply_info apply;
  203 
  204 #ifdef  NOTYET
  205         if (control && (error = ng_internalize(control, td))) {
  206                 if (pcbp->sockdata == NULL) {
  207                         error = ENOTCONN;
  208                         goto release;
  209                 }
  210         }
  211 #else   /* NOTYET */
  212         if (control) {
  213                 error = EINVAL;
  214                 goto release;
  215         }
  216 #endif  /* NOTYET */
  217 
  218         /* Require destination as there may be >= 1 hooks on this node. */
  219         if (addr == NULL) {
  220                 error = EDESTADDRREQ;
  221                 goto release;
  222         }
  223 
  224         /*
  225          * Allocate an expendable buffer for the path, chop off
  226          * the sockaddr header, and make sure it's NUL terminated.
  227          */
  228         len = sap->sg_len - 2;
  229         path = malloc(len + 1, M_NETGRAPH_PATH, M_WAITOK);
  230         bcopy(sap->sg_data, path, len);
  231         path[len] = '\0';
  232 
  233         /*
  234          * Move the actual message out of mbufs into a linear buffer.
  235          * Start by adding up the size of the data. (could use mh_len?)
  236          */
  237         for (len = 0, m0 = m; m0 != NULL; m0 = m0->m_next)
  238                 len += m0->m_len;
  239 
  240         /*
  241          * Move the data into a linear buffer as well.
  242          * Messages are not delivered in mbufs.
  243          */
  244         msg = malloc(len + 1, M_NETGRAPH_MSG, M_WAITOK);
  245         m_copydata(m, 0, len, (char *)msg);
  246 
  247         if (msg->header.version != NG_VERSION) {
  248                 free(msg, M_NETGRAPH_MSG);
  249                 error = EINVAL;
  250                 goto release;
  251         }
  252 
  253         /*
  254          * Hack alert!
  255          * We look into the message and if it mkpeers a node of unknown type, we
  256          * try to load it. We need to do this now, in syscall thread, because if
  257          * message gets queued and applied later we will get panic.
  258          */
  259         if (msg->header.typecookie == NGM_GENERIC_COOKIE &&
  260             msg->header.cmd == NGM_MKPEER) {
  261                 struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
  262 
  263                 if (ng_findtype(mkp->type) == NULL) {
  264                         char filename[NG_TYPESIZ + 3];
  265                         int fileid;
  266 
  267                         /* Not found, try to load it as a loadable module. */
  268                         snprintf(filename, sizeof(filename), "ng_%s",
  269                             mkp->type);
  270                         error = kern_kldload(curthread, filename, &fileid);
  271                         if (error != 0) {
  272                                 free(msg, M_NETGRAPH_MSG);
  273                                 goto release;
  274                         }
  275 
  276                         /* See if type has been loaded successfully. */
  277                         if (ng_findtype(mkp->type) == NULL) {
  278                                 free(msg, M_NETGRAPH_MSG);
  279                                 (void)kern_kldunload(curthread, fileid,
  280                                     LINKER_UNLOAD_NORMAL);
  281                                 error =  ENXIO;
  282                                 goto release;
  283                         }
  284                 }
  285         }
  286 
  287         item = ng_package_msg(msg, M_WAITOK);
  288         if ((error = ng_address_path((pcbp->sockdata->node), item, path, 0))
  289             != 0) {
  290 #ifdef TRACE_MESSAGES
  291                 printf("ng_address_path: errx=%d\n", error);
  292 #endif
  293                 goto release;
  294         }
  295 
  296 #ifdef TRACE_MESSAGES
  297         printf("[%x]:<---------[socket]: c=<%d>cmd=%x(%s) f=%x #%d (%s)\n",
  298                 item->el_dest->nd_ID,
  299                 msg->header.typecookie,
  300                 msg->header.cmd,
  301                 msg->header.cmdstr,
  302                 msg->header.flags,
  303                 msg->header.token,
  304                 item->el_dest->nd_type->name);
  305 #endif
  306         SAVE_LINE(item);
  307         /*
  308          * We do not want to return from syscall until the item
  309          * is processed by destination node. We register callback
  310          * on the item, which will update priv->error when item
  311          * was applied.
  312          * If ng_snd_item() has queued item, we sleep until
  313          * callback wakes us up.
  314          */
  315         bzero(&apply, sizeof(apply));
  316         apply.apply = ng_socket_item_applied;
  317         apply.context = priv;
  318         item->apply = &apply;
  319         priv->error = -1;
  320 
  321         error = ng_snd_item(item, 0);
  322 
  323         mtx_lock(&priv->mtx);
  324         if (priv->error == -1)
  325                 msleep(priv, &priv->mtx, 0, "ngsock", 0);
  326         mtx_unlock(&priv->mtx);
  327         KASSERT(priv->error != -1,
  328             ("ng_socket: priv->error wasn't updated"));
  329         error = priv->error;
  330 
  331 release:
  332         if (path != NULL)
  333                 free(path, M_NETGRAPH_PATH);
  334         if (control != NULL)
  335                 m_freem(control);
  336         if (m != NULL)
  337                 m_freem(m);
  338         return (error);
  339 }
  340 
  341 static int
  342 ngc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  343 {
  344         struct ngpcb *const pcbp = sotongpcb(so);
  345 
  346         if (pcbp == 0)
  347                 return (EINVAL);
  348         return (ng_bind(nam, pcbp));
  349 }
  350 
  351 static int
  352 ngc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
  353 {
  354         /*
  355          * At this time refuse to do this.. it used to
  356          * do something but it was undocumented and not used.
  357          */
  358         printf("program tried to connect control socket to remote node\n");
  359         return (EINVAL);
  360 }
  361 
  362 /***************************************************************
  363         Data sockets
  364 ***************************************************************/
  365 
  366 static int
  367 ngd_attach(struct socket *so, int proto, struct thread *td)
  368 {
  369         struct ngpcb *const pcbp = sotongpcb(so);
  370 
  371         if (pcbp != NULL)
  372                 return (EISCONN);
  373         return (ng_attach_data(so));
  374 }
  375 
  376 static void
  377 ngd_detach(struct socket *so)
  378 {
  379         struct ngpcb *const pcbp = sotongpcb(so);
  380 
  381         KASSERT(pcbp != NULL, ("ngd_detach: pcbp == NULL"));
  382         ng_detach_common(pcbp, NG_DATA);
  383 }
  384 
  385 static int
  386 ngd_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
  387          struct mbuf *control, struct thread *td)
  388 {
  389         struct ngpcb *const pcbp = sotongpcb(so);
  390         struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
  391         int     len, error;
  392         hook_p  hook = NULL;
  393         char    hookname[NG_HOOKSIZ];
  394 
  395         if ((pcbp == NULL) || (control != NULL)) {
  396                 error = EINVAL;
  397                 goto release;
  398         }
  399         if (pcbp->sockdata == NULL) {
  400                 error = ENOTCONN;
  401                 goto release;
  402         }
  403 
  404         if (sap == NULL)
  405                 len = 0;                /* Make compiler happy. */
  406         else
  407                 len = sap->sg_len - 2;
  408 
  409         /*
  410          * If the user used any of these ways to not specify an address
  411          * then handle specially.
  412          */
  413         if ((sap == NULL) || (len <= 0) || (*sap->sg_data == '\0')) {
  414                 if (NG_NODE_NUMHOOKS(pcbp->sockdata->node) != 1) {
  415                         error = EDESTADDRREQ;
  416                         goto release;
  417                 }
  418                 /*
  419                  * If exactly one hook exists, just use it.
  420                  * Special case to allow write(2) to work on an ng_socket.
  421                  */
  422                 hook = LIST_FIRST(&pcbp->sockdata->node->nd_hooks);
  423         } else {
  424                 if (len >= NG_HOOKSIZ) {
  425                         error = EINVAL;
  426                         goto release;
  427                 }
  428 
  429                 /*
  430                  * chop off the sockaddr header, and make sure it's NUL
  431                  * terminated
  432                  */
  433                 bcopy(sap->sg_data, hookname, len);
  434                 hookname[len] = '\0';
  435 
  436                 /* Find the correct hook from 'hookname' */
  437                 hook = ng_findhook(pcbp->sockdata->node, hookname);
  438                 if (hook == NULL) {
  439                         error = EHOSTUNREACH;
  440                         goto release;
  441                 }
  442         }
  443 
  444         /* Send data. */
  445         NG_SEND_DATA_FLAGS(error, hook, m, NG_WAITOK);
  446 
  447 release:
  448         if (control != NULL)
  449                 m_freem(control);
  450         if (m != NULL)
  451                 m_freem(m);
  452         return (error);
  453 }
  454 
  455 static int
  456 ngd_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
  457 {
  458         struct ngpcb *const pcbp = sotongpcb(so);
  459 
  460         if (pcbp == 0)
  461                 return (EINVAL);
  462         return (ng_connect_data(nam, pcbp));
  463 }
  464 
  465 /*
  466  * Used for both data and control sockets
  467  */
  468 static int
  469 ng_getsockaddr(struct socket *so, struct sockaddr **addr)
  470 {
  471         struct ngpcb *pcbp;
  472         struct sockaddr_ng *sg;
  473         int sg_len;
  474         int error = 0;
  475 
  476         /* Why isn't sg_data a `char[1]' ? :-( */
  477         sg_len = sizeof(struct sockaddr_ng) - sizeof(sg->sg_data) + 1;
  478 
  479         pcbp = sotongpcb(so);
  480         if ((pcbp == NULL) || (pcbp->sockdata == NULL))
  481                 /* XXXGL: can this still happen? */
  482                 return (EINVAL);
  483 
  484         mtx_lock(&pcbp->sockdata->mtx);
  485         if (pcbp->sockdata->node != NULL) {
  486                 node_p node = pcbp->sockdata->node;
  487                 int namelen = 0;        /* silence compiler! */
  488 
  489                 if (NG_NODE_HAS_NAME(node))
  490                         sg_len += namelen = strlen(NG_NODE_NAME(node));
  491 
  492                 sg = malloc(sg_len, M_SONAME, M_WAITOK | M_ZERO);
  493 
  494                 if (NG_NODE_HAS_NAME(node))
  495                         bcopy(NG_NODE_NAME(node), sg->sg_data, namelen);
  496 
  497                 sg->sg_len = sg_len;
  498                 sg->sg_family = AF_NETGRAPH;
  499                 *addr = (struct sockaddr *)sg;
  500                 mtx_unlock(&pcbp->sockdata->mtx);
  501         } else {
  502                 mtx_unlock(&pcbp->sockdata->mtx);
  503                 error = EINVAL;
  504         }
  505 
  506         return (error);
  507 }
  508 
  509 /*
  510  * Attach a socket to it's protocol specific partner.
  511  * For a control socket, actually create a netgraph node and attach
  512  * to it as well.
  513  */
  514 
  515 static int
  516 ng_attach_cntl(struct socket *so)
  517 {
  518         struct ngsock *priv;
  519         struct ngpcb *pcbp;
  520         int error;
  521 
  522         /* Allocate node private info */
  523         priv = malloc(sizeof(*priv), M_NETGRAPH_SOCK, M_WAITOK | M_ZERO);
  524 
  525         /* Setup protocol control block */
  526         if ((error = ng_attach_common(so, NG_CONTROL)) != 0) {
  527                 free(priv, M_NETGRAPH_SOCK);
  528                 return (error);
  529         }
  530         pcbp = sotongpcb(so);
  531 
  532         /* Link the pcb the private data. */
  533         priv->ctlsock = pcbp;
  534         pcbp->sockdata = priv;
  535         priv->refs++;
  536 
  537         /* Initialize mutex. */
  538         mtx_init(&priv->mtx, "ng_socket", NULL, MTX_DEF);
  539 
  540         /* Make the generic node components */
  541         if ((error = ng_make_node_common(&typestruct, &priv->node)) != 0) {
  542                 free(priv, M_NETGRAPH_SOCK);
  543                 ng_detach_common(pcbp, NG_CONTROL);
  544                 return (error);
  545         }
  546 
  547         /* Link the node and the private data. */
  548         NG_NODE_SET_PRIVATE(priv->node, priv);
  549         NG_NODE_REF(priv->node);
  550         priv->refs++;
  551 
  552         return (0);
  553 }
  554 
  555 static int
  556 ng_attach_data(struct socket *so)
  557 {
  558         return (ng_attach_common(so, NG_DATA));
  559 }
  560 
  561 /*
  562  * Set up a socket protocol control block.
  563  * This code is shared between control and data sockets.
  564  */
  565 static int
  566 ng_attach_common(struct socket *so, int type)
  567 {
  568         struct ngpcb *pcbp;
  569         int error;
  570 
  571         /* Standard socket setup stuff. */
  572         error = soreserve(so, ngpdg_sendspace, ngpdg_recvspace);
  573         if (error)
  574                 return (error);
  575 
  576         /* Allocate the pcb. */
  577         pcbp = malloc(sizeof(struct ngpcb), M_PCB, M_WAITOK | M_ZERO);
  578         pcbp->type = type;
  579 
  580         /* Link the pcb and the socket. */
  581         so->so_pcb = (caddr_t)pcbp;
  582         pcbp->ng_socket = so;
  583 
  584         return (0);
  585 }
  586 
  587 /*
  588  * Disassociate the socket from it's protocol specific
  589  * partner. If it's attached to a node's private data structure,
  590  * then unlink from that too. If we were the last socket attached to it,
  591  * then shut down the entire node. Shared code for control and data sockets.
  592  */
  593 static void
  594 ng_detach_common(struct ngpcb *pcbp, int which)
  595 {
  596         struct ngsock *priv = pcbp->sockdata;
  597 
  598         if (priv != NULL) {
  599                 mtx_lock(&priv->mtx);
  600 
  601                 switch (which) {
  602                 case NG_CONTROL:
  603                         priv->ctlsock = NULL;
  604                         break;
  605                 case NG_DATA:
  606                         priv->datasock = NULL;
  607                         break;
  608                 default:
  609                         panic(__func__);
  610                 }
  611                 pcbp->sockdata = NULL;
  612 
  613                 ng_socket_free_priv(priv);
  614         }
  615 
  616         pcbp->ng_socket->so_pcb = NULL;
  617         free(pcbp, M_PCB);
  618 }
  619 
  620 /*
  621  * Remove a reference from node private data.
  622  */
  623 static void
  624 ng_socket_free_priv(struct ngsock *priv)
  625 {
  626         mtx_assert(&priv->mtx, MA_OWNED);
  627 
  628         priv->refs--;
  629 
  630         if (priv->refs == 0) {
  631                 mtx_destroy(&priv->mtx);
  632                 free(priv, M_NETGRAPH_SOCK);
  633                 return;
  634         }
  635 
  636         if ((priv->refs == 1) && (priv->node != NULL)) {
  637                 node_p node = priv->node;
  638 
  639                 priv->node = NULL;
  640                 mtx_unlock(&priv->mtx);
  641                 NG_NODE_UNREF(node);
  642                 ng_rmnode_self(node);
  643         } else
  644                 mtx_unlock(&priv->mtx);
  645 }
  646 
  647 #ifdef NOTYET
  648 /*
  649  * File descriptors can be passed into an AF_NETGRAPH socket.
  650  * Note, that file descriptors cannot be passed OUT.
  651  * Only character device descriptors are accepted.
  652  * Character devices are useful to connect a graph to a device,
  653  * which after all is the purpose of this whole system.
  654  */
  655 static int
  656 ng_internalize(struct mbuf *control, struct thread *td)
  657 {
  658         const struct cmsghdr *cm = mtod(control, const struct cmsghdr *);
  659         struct file *fp;
  660         struct vnode *vn;
  661         int oldfds;
  662         int fd;
  663 
  664         if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
  665             cm->cmsg_len != control->m_len) {
  666                 TRAP_ERROR;
  667                 return (EINVAL);
  668         }
  669 
  670         /* Check there is only one FD. XXX what would more than one signify? */
  671         oldfds = ((caddr_t)cm + cm->cmsg_len - (caddr_t)data) / sizeof (int);
  672         if (oldfds != 1) {
  673                 TRAP_ERROR;
  674                 return (EINVAL);
  675         }
  676 
  677         /* Check that the FD given is legit. and change it to a pointer to a
  678          * struct file. */
  679         fd = CMSG_DATA(cm);
  680         if ((error = fget(td, fd, &fp)) != 0)
  681                 return (error);
  682 
  683         /* Depending on what kind of resource it is, act differently. For
  684          * devices, we treat it as a file. For an AF_NETGRAPH socket,
  685          * shortcut straight to the node. */
  686         switch (fp->f_type) {
  687         case DTYPE_VNODE:
  688                 vn = fp->f_data;
  689                 if (vn && (vn->v_type == VCHR)) {
  690                         /* for a VCHR, actually reference the FILE */
  691                         fp->f_count++;
  692                         /* XXX then what :) */
  693                         /* how to pass on to other modules? */
  694                 } else {
  695                         fdrop(fp, td);
  696                         TRAP_ERROR;
  697                         return (EINVAL);
  698                 }
  699                 break;
  700         default:
  701                 fdrop(fp, td);
  702                 TRAP_ERROR;
  703                 return (EINVAL);
  704         }
  705         fdrop(fp, td);
  706         return (0);
  707 }
  708 #endif  /* NOTYET */
  709 
  710 /*
  711  * Connect the data socket to a named control socket node.
  712  */
  713 static int
  714 ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp)
  715 {
  716         struct sockaddr_ng *sap;
  717         node_p farnode;
  718         struct ngsock *priv;
  719         int error;
  720         item_p item;
  721 
  722         /* If we are already connected, don't do it again. */
  723         if (pcbp->sockdata != NULL)
  724                 return (EISCONN);
  725 
  726         /*
  727          * Find the target (victim) and check it doesn't already have
  728          * a data socket. Also check it is a 'socket' type node.
  729          * Use ng_package_data() and ng_address_path() to do this.
  730          */
  731 
  732         sap = (struct sockaddr_ng *) nam;
  733         /* The item will hold the node reference. */
  734         item = ng_package_data(NULL, NG_WAITOK);
  735 
  736         if ((error = ng_address_path(NULL, item,  sap->sg_data, 0)))
  737                 return (error); /* item is freed on failure */
  738 
  739         /*
  740          * Extract node from item and free item. Remember we now have
  741          * a reference on the node. The item holds it for us.
  742          * when we free the item we release the reference.
  743          */
  744         farnode = item->el_dest; /* shortcut */
  745         if (strcmp(farnode->nd_type->name, NG_SOCKET_NODE_TYPE) != 0) {
  746                 NG_FREE_ITEM(item); /* drop the reference to the node */
  747                 return (EINVAL);
  748         }
  749         priv = NG_NODE_PRIVATE(farnode);
  750         if (priv->datasock != NULL) {
  751                 NG_FREE_ITEM(item);     /* drop the reference to the node */
  752                 return (EADDRINUSE);
  753         }
  754 
  755         /*
  756          * Link the PCB and the private data struct. and note the extra
  757          * reference. Drop the extra reference on the node.
  758          */
  759         mtx_lock(&priv->mtx);
  760         priv->datasock = pcbp;
  761         pcbp->sockdata = priv;
  762         priv->refs++;
  763         mtx_unlock(&priv->mtx);
  764         NG_FREE_ITEM(item);     /* drop the reference to the node */
  765         return (0);
  766 }
  767 
  768 /*
  769  * Binding a socket means giving the corresponding node a name
  770  */
  771 static int
  772 ng_bind(struct sockaddr *nam, struct ngpcb *pcbp)
  773 {
  774         struct ngsock *const priv = pcbp->sockdata;
  775         struct sockaddr_ng *const sap = (struct sockaddr_ng *) nam;
  776 
  777         if (priv == NULL) {
  778                 TRAP_ERROR;
  779                 return (EINVAL);
  780         }
  781         if ((sap->sg_len < 4) || (sap->sg_len > (NG_NODESIZ + 2)) ||
  782             (sap->sg_data[0] == '\0') ||
  783             (sap->sg_data[sap->sg_len - 3] != '\0')) {
  784                 TRAP_ERROR;
  785                 return (EINVAL);
  786         }
  787         return (ng_name_node(priv->node, sap->sg_data));
  788 }
  789 
  790 /***************************************************************
  791         Netgraph node
  792 ***************************************************************/
  793 
  794 /*
  795  * You can only create new nodes from the socket end of things.
  796  */
  797 static int
  798 ngs_constructor(node_p nodep)
  799 {
  800         return (EINVAL);
  801 }
  802 
  803 /*
  804  * We allow any hook to be connected to the node.
  805  * There is no per-hook private information though.
  806  */
  807 static int
  808 ngs_newhook(node_p node, hook_p hook, const char *name)
  809 {
  810         NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
  811         return (0);
  812 }
  813 
  814 /*
  815  * If only one hook, allow read(2) and write(2) to work.
  816  */
  817 static int
  818 ngs_connect(hook_p hook)
  819 {
  820         node_p node = NG_HOOK_NODE(hook);
  821         struct ngsock *priv = NG_NODE_PRIVATE(node);
  822 
  823         if ((priv->datasock) && (priv->datasock->ng_socket)) {
  824                 if (NG_NODE_NUMHOOKS(node) == 1)
  825                         priv->datasock->ng_socket->so_state |= SS_ISCONNECTED;
  826                 else
  827                         priv->datasock->ng_socket->so_state &= ~SS_ISCONNECTED;
  828         }
  829         return (0);
  830 }
  831 
  832 /*
  833  * Incoming messages get passed up to the control socket.
  834  * Unless they are for us specifically (socket_type)
  835  */
  836 static int
  837 ngs_rcvmsg(node_p node, item_p item, hook_p lasthook)
  838 {
  839         struct ngsock *const priv = NG_NODE_PRIVATE(node);
  840         struct ngpcb *const pcbp = priv->ctlsock;
  841         struct socket *so;
  842         struct sockaddr_ng addr;
  843         struct ng_mesg *msg;
  844         struct mbuf *m;
  845         ng_ID_t retaddr = NGI_RETADDR(item);
  846         int addrlen;
  847         int error = 0;
  848 
  849         NGI_GET_MSG(item, msg);
  850         NG_FREE_ITEM(item);
  851 
  852         /*
  853          * Only allow mesgs to be passed if we have the control socket.
  854          * Data sockets can only support the generic messages.
  855          */
  856         if (pcbp == NULL) {
  857                 TRAP_ERROR;
  858                 NG_FREE_MSG(msg);
  859                 return (EINVAL);
  860         }
  861         so = pcbp->ng_socket;
  862 
  863 #ifdef TRACE_MESSAGES
  864         printf("[%x]:---------->[socket]: c=<%d>cmd=%x(%s) f=%x #%d\n",
  865                 retaddr,
  866                 msg->header.typecookie,
  867                 msg->header.cmd,
  868                 msg->header.cmdstr,
  869                 msg->header.flags,
  870                 msg->header.token);
  871 #endif
  872 
  873         if (msg->header.typecookie == NGM_SOCKET_COOKIE) {
  874                 switch (msg->header.cmd) {
  875                 case NGM_SOCK_CMD_NOLINGER:
  876                         priv->flags |= NGS_FLAG_NOLINGER;
  877                         break;
  878                 case NGM_SOCK_CMD_LINGER:
  879                         priv->flags &= ~NGS_FLAG_NOLINGER;
  880                         break;
  881                 default:
  882                         error = EINVAL;         /* unknown command */
  883                 }
  884                 /* Free the message and return. */
  885                 NG_FREE_MSG(msg);
  886                 return (error);
  887         }
  888 
  889         /* Get the return address into a sockaddr. */
  890         bzero(&addr, sizeof(addr));
  891         addr.sg_len = sizeof(addr);
  892         addr.sg_family = AF_NETGRAPH;
  893         addrlen = snprintf((char *)&addr.sg_data, sizeof(addr.sg_data),
  894             "[%x]:", retaddr);
  895         if (addrlen < 0 || addrlen > sizeof(addr.sg_data)) {
  896                 printf("%s: snprintf([%x]) failed - %d\n", __func__, retaddr,
  897                     addrlen);
  898                 NG_FREE_MSG(msg);
  899                 return (EINVAL);
  900         }
  901 
  902         /* Copy the message itself into an mbuf chain. */
  903         m = m_devget((caddr_t)msg, sizeof(struct ng_mesg) + msg->header.arglen,
  904             0, NULL, NULL);
  905 
  906         /*
  907          * Here we free the message. We need to do that
  908          * regardless of whether we got mbufs.
  909          */
  910         NG_FREE_MSG(msg);
  911 
  912         if (m == NULL) {
  913                 TRAP_ERROR;
  914                 return (ENOBUFS);
  915         }
  916 
  917         /* Send it up to the socket. */
  918         if (sbappendaddr(&so->so_rcv, (struct sockaddr *)&addr, m, NULL) == 0) {
  919                 TRAP_ERROR;
  920                 m_freem(m);
  921                 return (ENOBUFS);
  922         }
  923         sorwakeup(so);
  924         
  925         return (error);
  926 }
  927 
  928 /*
  929  * Receive data on a hook
  930  */
  931 static int
  932 ngs_rcvdata(hook_p hook, item_p item)
  933 {
  934         struct ngsock *const priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  935         struct ngpcb *const pcbp = priv->datasock;
  936         struct socket *so;
  937         struct sockaddr_ng *addr;
  938         char *addrbuf[NG_HOOKSIZ + 4];
  939         int addrlen;
  940         struct mbuf *m;
  941 
  942         NGI_GET_M(item, m);
  943         NG_FREE_ITEM(item);
  944 
  945         /* If there is no data socket, black-hole it. */
  946         if (pcbp == NULL) {
  947                 NG_FREE_M(m);
  948                 return (0);
  949         }
  950         so = pcbp->ng_socket;
  951 
  952         /* Get the return address into a sockaddr. */
  953         addrlen = strlen(NG_HOOK_NAME(hook));   /* <= NG_HOOKSIZ - 1 */
  954         addr = (struct sockaddr_ng *) addrbuf;
  955         addr->sg_len = addrlen + 3;
  956         addr->sg_family = AF_NETGRAPH;
  957         bcopy(NG_HOOK_NAME(hook), addr->sg_data, addrlen);
  958         addr->sg_data[addrlen] = '\0';
  959 
  960         /* Try to tell the socket which hook it came in on. */
  961         if (sbappendaddr(&so->so_rcv, (struct sockaddr *)addr, m, NULL) == 0) {
  962                 m_freem(m);
  963                 TRAP_ERROR;
  964                 return (ENOBUFS);
  965         }
  966         sorwakeup(so);
  967         return (0);
  968 }
  969 
  970 /*
  971  * Hook disconnection
  972  *
  973  * For this type, removal of the last link destroys the node
  974  * if the NOLINGER flag is set.
  975  */
  976 static int
  977 ngs_disconnect(hook_p hook)
  978 {
  979         node_p node = NG_HOOK_NODE(hook);
  980         struct ngsock *const priv = NG_NODE_PRIVATE(node);
  981 
  982         if ((priv->datasock) && (priv->datasock->ng_socket)) {
  983                 if (NG_NODE_NUMHOOKS(node) == 1)
  984                         priv->datasock->ng_socket->so_state |= SS_ISCONNECTED;
  985                 else
  986                         priv->datasock->ng_socket->so_state &= ~SS_ISCONNECTED;
  987         }
  988 
  989         if ((priv->flags & NGS_FLAG_NOLINGER) &&
  990             (NG_NODE_NUMHOOKS(node) == 0) && (NG_NODE_IS_VALID(node)))
  991                 ng_rmnode_self(node);
  992 
  993         return (0);
  994 }
  995 
  996 /*
  997  * Do local shutdown processing.
  998  * In this case, that involves making sure the socket
  999  * knows we should be shutting down.
 1000  */
 1001 static int
 1002 ngs_shutdown(node_p node)
 1003 {
 1004         struct ngsock *const priv = NG_NODE_PRIVATE(node);
 1005         struct ngpcb *const dpcbp = priv->datasock;
 1006         struct ngpcb *const pcbp = priv->ctlsock;
 1007 
 1008         if (dpcbp != NULL)
 1009                 soisdisconnected(dpcbp->ng_socket);
 1010 
 1011         if (pcbp != NULL)
 1012                 soisdisconnected(pcbp->ng_socket);
 1013 
 1014         mtx_lock(&priv->mtx);
 1015         priv->node = NULL;
 1016         NG_NODE_SET_PRIVATE(node, NULL);
 1017         ng_socket_free_priv(priv);
 1018 
 1019         NG_NODE_UNREF(node);
 1020         return (0);
 1021 }
 1022 
 1023 static void
 1024 ng_socket_item_applied(void *context, int error)
 1025 {
 1026         struct ngsock *const priv = (struct ngsock *)context;
 1027 
 1028         mtx_lock(&priv->mtx);
 1029         priv->error = error;
 1030         wakeup(priv);
 1031         mtx_unlock(&priv->mtx);
 1032 
 1033 }
 1034 
 1035 static  int
 1036 dummy_disconnect(struct socket *so)
 1037 {
 1038         return (0);
 1039 }
 1040 /*
 1041  * Control and data socket type descriptors
 1042  *
 1043  * XXXRW: Perhaps _close should do something?
 1044  */
 1045 
 1046 static struct pr_usrreqs ngc_usrreqs = {
 1047         .pru_abort =            NULL,
 1048         .pru_attach =           ngc_attach,
 1049         .pru_bind =             ngc_bind,
 1050         .pru_connect =          ngc_connect,
 1051         .pru_detach =           ngc_detach,
 1052         .pru_disconnect =       dummy_disconnect,
 1053         .pru_peeraddr =         NULL,
 1054         .pru_send =             ngc_send,
 1055         .pru_shutdown =         NULL,
 1056         .pru_sockaddr =         ng_getsockaddr,
 1057         .pru_close =            NULL,
 1058 };
 1059 
 1060 static struct pr_usrreqs ngd_usrreqs = {
 1061         .pru_abort =            NULL,
 1062         .pru_attach =           ngd_attach,
 1063         .pru_bind =             NULL,
 1064         .pru_connect =          ngd_connect,
 1065         .pru_detach =           ngd_detach,
 1066         .pru_disconnect =       dummy_disconnect,
 1067         .pru_peeraddr =         NULL,
 1068         .pru_send =             ngd_send,
 1069         .pru_shutdown =         NULL,
 1070         .pru_sockaddr =         ng_getsockaddr,
 1071         .pru_close =            NULL,
 1072 };
 1073 
 1074 /*
 1075  * Definitions of protocols supported in the NETGRAPH domain.
 1076  */
 1077 
 1078 extern struct domain ngdomain;          /* stop compiler warnings */
 1079 
 1080 static struct protosw ngsw[] = {
 1081 {
 1082         .pr_type =              SOCK_DGRAM,
 1083         .pr_domain =            &ngdomain,
 1084         .pr_protocol =          NG_CONTROL,
 1085         .pr_flags =             PR_ATOMIC | PR_ADDR /* | PR_RIGHTS */,
 1086         .pr_usrreqs =           &ngc_usrreqs
 1087 },
 1088 {
 1089         .pr_type =              SOCK_DGRAM,
 1090         .pr_domain =            &ngdomain,
 1091         .pr_protocol =          NG_DATA,
 1092         .pr_flags =             PR_ATOMIC | PR_ADDR,
 1093         .pr_usrreqs =           &ngd_usrreqs
 1094 }
 1095 };
 1096 
 1097 struct domain ngdomain = {
 1098         .dom_family =           AF_NETGRAPH,
 1099         .dom_name =             "netgraph",
 1100         .dom_protosw =          ngsw,
 1101         .dom_protoswNPROTOSW =  &ngsw[sizeof(ngsw) / sizeof(ngsw[0])]
 1102 };
 1103 
 1104 /*
 1105  * Handle loading and unloading for this node type.
 1106  * This is to handle auxiliary linkages (e.g protocol domain addition).
 1107  */
 1108 static int
 1109 ngs_mod_event(module_t mod, int event, void *data)
 1110 {
 1111         int error = 0;
 1112 
 1113         switch (event) {
 1114         case MOD_LOAD:
 1115                 /* Register protocol domain. */
 1116                 net_add_domain(&ngdomain);
 1117                 break;
 1118         case MOD_UNLOAD:
 1119 #ifdef NOTYET
 1120                 /* Unregister protocol domain XXX can't do this yet.. */
 1121                 if ((error = net_rm_domain(&ngdomain)) != 0)
 1122                         break;
 1123                 else
 1124 #endif
 1125                         error = EBUSY;
 1126                 break;
 1127         default:
 1128                 error = EOPNOTSUPP;
 1129                 break;
 1130         }
 1131         return (error);
 1132 }
 1133 
 1134 SYSCTL_INT(_net_graph, OID_AUTO, family, CTLFLAG_RD, 0, AF_NETGRAPH, "");
 1135 SYSCTL_NODE(_net_graph, OID_AUTO, data, CTLFLAG_RW, 0, "DATA");
 1136 SYSCTL_INT(_net_graph_data, OID_AUTO, proto, CTLFLAG_RD, 0, NG_DATA, "");
 1137 SYSCTL_NODE(_net_graph, OID_AUTO, control, CTLFLAG_RW, 0, "CONTROL");
 1138 SYSCTL_INT(_net_graph_control, OID_AUTO, proto, CTLFLAG_RD, 0, NG_CONTROL, "");
 1139 

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