The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_device.c

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    1 /*-
    2  * Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
    3  * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
    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  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   24  *
   25  * Netgraph "device" node
   26  *
   27  * This node presents a /dev/ngd%d device that interfaces to an other
   28  * netgraph node.
   29  *
   30  * $FreeBSD$
   31  *
   32  */
   33 
   34 #if 0
   35 #define DBG do { printf("ng_device: %s\n", __func__ ); } while (0)
   36 #else
   37 #define DBG do {} while (0)
   38 #endif
   39 
   40 #include <sys/param.h>
   41 #include <sys/conf.h>
   42 #include <sys/ioccom.h>
   43 #include <sys/kernel.h>
   44 #include <sys/malloc.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/poll.h>
   47 #include <sys/queue.h>
   48 #include <sys/socket.h>
   49 #include <sys/systm.h>
   50 #include <sys/uio.h>
   51 #include <sys/vnode.h>
   52 
   53 #include <net/if.h>
   54 #include <net/if_var.h>
   55 #include <netinet/in.h>
   56 #include <netinet/in_systm.h>
   57 #include <netinet/ip.h>
   58 
   59 #include <netgraph/ng_message.h>
   60 #include <netgraph/netgraph.h>
   61 #include <netgraph/ng_device.h>
   62 
   63 #define ERROUT(x) do { error = (x); goto done; } while (0)
   64 
   65 /* Netgraph methods */
   66 static int              ng_device_mod_event(module_t, int, void *);
   67 static ng_constructor_t ng_device_constructor;
   68 static ng_rcvmsg_t      ng_device_rcvmsg;
   69 static ng_shutdown_t    ng_device_shutdown;
   70 static ng_newhook_t     ng_device_newhook;
   71 static ng_rcvdata_t     ng_device_rcvdata;
   72 static ng_disconnect_t  ng_device_disconnect;
   73 
   74 /* Netgraph type */
   75 static struct ng_type ngd_typestruct = {
   76         .version =      NG_ABI_VERSION,
   77         .name =         NG_DEVICE_NODE_TYPE,
   78         .mod_event =    ng_device_mod_event,
   79         .constructor =  ng_device_constructor,
   80         .rcvmsg =       ng_device_rcvmsg,
   81         .shutdown =     ng_device_shutdown,
   82         .newhook =      ng_device_newhook,
   83         .rcvdata =      ng_device_rcvdata,
   84         .disconnect =   ng_device_disconnect,
   85 };
   86 NETGRAPH_INIT(device, &ngd_typestruct);
   87 
   88 /* per node data */
   89 struct ngd_private {
   90         struct  ifqueue readq;
   91         struct  ng_node *node;
   92         struct  ng_hook *hook;
   93         struct  cdev    *ngddev;
   94         struct  mtx     ngd_mtx;
   95         int             unit;
   96         uint16_t        flags;
   97 #define NGDF_OPEN       0x0001
   98 #define NGDF_RWAIT      0x0002
   99 };
  100 typedef struct ngd_private *priv_p;
  101 
  102 /* unit number allocator entity */
  103 static struct unrhdr *ngd_unit;
  104 
  105 /* Maximum number of NGD devices */
  106 #define MAX_NGD 999
  107 
  108 static d_close_t ngdclose;
  109 static d_open_t ngdopen;
  110 static d_read_t ngdread;
  111 static d_write_t ngdwrite;
  112 #if 0
  113 static d_ioctl_t ngdioctl;
  114 #endif
  115 static d_poll_t ngdpoll;
  116 
  117 static struct cdevsw ngd_cdevsw = {
  118         .d_version =    D_VERSION,
  119         .d_open =       ngdopen,
  120         .d_close =      ngdclose,
  121         .d_read =       ngdread,
  122         .d_write =      ngdwrite,
  123 #if 0
  124         .d_ioctl =      ngdioctl,
  125 #endif
  126         .d_poll =       ngdpoll,
  127         .d_name =       NG_DEVICE_DEVNAME,
  128 };
  129 
  130 /******************************************************************************
  131  *  Netgraph methods
  132  ******************************************************************************/
  133 
  134 /*
  135  * Handle loading and unloading for this node type.
  136  */
  137 static int
  138 ng_device_mod_event(module_t mod, int event, void *data)
  139 {
  140         int error = 0;
  141 
  142         switch (event) {
  143         case MOD_LOAD:
  144                 ngd_unit = new_unrhdr(0, MAX_NGD, NULL);
  145                 break;
  146         case MOD_UNLOAD:
  147                 delete_unrhdr(ngd_unit);
  148                 break;
  149         default:
  150                 error = EOPNOTSUPP;
  151                 break;
  152         }
  153         return (error);
  154 }
  155 
  156 /*
  157  * create new node
  158  */
  159 static int
  160 ng_device_constructor(node_p node)
  161 {
  162         priv_p  priv;
  163 
  164         DBG;
  165 
  166         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
  167         if (priv == NULL)
  168                 return (ENOMEM);
  169 
  170         /* Allocate unit number */
  171         priv->unit = alloc_unr(ngd_unit);
  172 
  173         /* Initialize mutexes and queue */
  174         mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
  175         mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
  176         IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
  177 
  178         /* Link everything together */
  179         NG_NODE_SET_PRIVATE(node, priv);
  180         priv->node = node;
  181 
  182         priv->ngddev = make_dev(&ngd_cdevsw, unit2minor(priv->unit), UID_ROOT,
  183             GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
  184         if(priv->ngddev == NULL) {
  185                 printf("%s(): make_dev() failed\n",__func__);
  186                 mtx_destroy(&priv->ngd_mtx);
  187                 mtx_destroy(&priv->readq.ifq_mtx);
  188                 free_unr(ngd_unit, priv->unit);
  189                 FREE(priv, M_NETGRAPH);
  190                 return(EINVAL);
  191         }
  192         /* XXX: race here? */
  193         priv->ngddev->si_drv1 = priv;
  194 
  195         return(0);
  196 }
  197 
  198 /*
  199  * Process control message.
  200  */
  201 
  202 static int
  203 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
  204 {
  205         const priv_p priv = NG_NODE_PRIVATE(node);
  206         struct ng_mesg *msg;
  207         struct ng_mesg *resp = NULL;
  208         int error = 0;
  209 
  210         NGI_GET_MSG(item, msg);
  211 
  212         if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
  213                 switch (msg->header.cmd) {
  214                 case NGM_DEVICE_GET_DEVNAME:
  215                         /* XXX: Fix when MAX_NGD us bigger */
  216                         NG_MKRESPONSE(resp, msg,
  217                             strlen(NG_DEVICE_DEVNAME) + 4, M_NOWAIT);
  218 
  219                         if (resp == NULL)
  220                                 ERROUT(ENOMEM);
  221 
  222                         strlcpy((char *)resp->data, priv->ngddev->si_name,
  223                             strlen(priv->ngddev->si_name) + 1);
  224                         break;
  225 
  226                 default:
  227                         error = EINVAL;
  228                         break;
  229                 }
  230         } else
  231                 error = EINVAL;
  232 
  233 done:
  234         NG_RESPOND_MSG(error, node, item, resp);
  235         NG_FREE_MSG(msg);
  236         return (error);
  237 }
  238 
  239 /*
  240  * Accept incoming hook. We support only one hook per node.
  241  */
  242 static int
  243 ng_device_newhook(node_p node, hook_p hook, const char *name)
  244 {
  245         priv_p priv = NG_NODE_PRIVATE(node);
  246 
  247         DBG;
  248 
  249         /* We have only one hook per node */
  250         if (priv->hook != NULL)
  251                 return (EISCONN);
  252 
  253         priv->hook = hook;
  254 
  255         return(0);
  256 }
  257 
  258 /*
  259  * Receive data from hook, write it to device.
  260  */
  261 static int
  262 ng_device_rcvdata(hook_p hook, item_p item)
  263 {
  264         priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  265         struct mbuf *m;
  266 
  267         DBG;
  268 
  269         NGI_GET_M(item, m);
  270         NG_FREE_ITEM(item);
  271 
  272         IF_LOCK(&priv->readq);
  273         if (_IF_QFULL(&priv->readq)) {
  274                 _IF_DROP(&priv->readq);
  275                 IF_UNLOCK(&priv->readq);
  276                 NG_FREE_M(m);
  277                 return (ENOBUFS);
  278         }
  279 
  280         _IF_ENQUEUE(&priv->readq, m);
  281         IF_UNLOCK(&priv->readq);
  282         mtx_lock(&priv->ngd_mtx);
  283         if (priv->flags & NGDF_RWAIT) {
  284                 priv->flags &= ~NGDF_RWAIT;
  285                 wakeup(priv);
  286         }
  287         mtx_unlock(&priv->ngd_mtx);
  288 
  289         return(0);
  290 }
  291 
  292 /*
  293  * Removal of the hook destroys the node.
  294  */
  295 static int
  296 ng_device_disconnect(hook_p hook)
  297 {
  298         priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  299 
  300         DBG;
  301 
  302         destroy_dev(priv->ngddev);
  303         mtx_destroy(&priv->ngd_mtx);
  304 
  305         IF_DRAIN(&priv->readq);
  306         mtx_destroy(&(priv)->readq.ifq_mtx);
  307 
  308         free_unr(ngd_unit, priv->unit);
  309 
  310         FREE(priv, M_NETGRAPH);
  311 
  312         ng_rmnode_self(NG_HOOK_NODE(hook));
  313 
  314         return(0);
  315 }
  316 
  317 /*
  318  * Node shutdown. Everything is already done in disconnect method.
  319  */
  320 static int
  321 ng_device_shutdown(node_p node)
  322 {
  323         NG_NODE_UNREF(node);
  324         return (0);
  325 }
  326 
  327 /******************************************************************************
  328  *  Device methods
  329  ******************************************************************************/
  330 
  331 /*
  332  * the device is opened
  333  */
  334 static int
  335 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
  336 {
  337         priv_p  priv = (priv_p )dev->si_drv1;
  338 
  339         DBG;
  340 
  341         mtx_lock(&priv->ngd_mtx);
  342         priv->flags |= NGDF_OPEN;
  343         mtx_unlock(&priv->ngd_mtx);
  344 
  345         return(0);
  346 }
  347 
  348 /*
  349  * the device is closed
  350  */
  351 static int
  352 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
  353 {
  354         priv_p  priv = (priv_p )dev->si_drv1;
  355 
  356         DBG;
  357         mtx_lock(&priv->ngd_mtx);
  358         priv->flags &= ~NGDF_OPEN;
  359         mtx_unlock(&priv->ngd_mtx);
  360 
  361         return(0);
  362 }
  363 
  364 #if 0   /*
  365          * The ioctl is transformed into netgraph control message.
  366          * We do not process them, yet.
  367          */
  368 /*
  369  * process ioctl
  370  *
  371  * they are translated into netgraph messages and passed on
  372  *
  373  */
  374 static int
  375 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
  376 {
  377         struct ngd_softc *sc = &ngd_softc;
  378         struct ngd_connection * connection = NULL;
  379         struct ngd_connection * tmp;
  380         int error = 0;
  381         struct ng_mesg *msg;
  382         struct ngd_param_s * datap;
  383 
  384         DBG;
  385 
  386         NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
  387                         M_NOWAIT);
  388         if (msg == NULL) {
  389                 printf("%s(): msg == NULL\n",__func__);
  390                 goto nomsg;
  391         }
  392 
  393         /* pass the ioctl data into the ->data area */
  394         datap = (struct ngd_param_s *)msg->data;
  395         datap->p = addr;
  396 
  397         NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
  398         if(error)
  399                 printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
  400 
  401 nomsg:
  402 
  403         return(0);
  404 }
  405 #endif /* if 0 */
  406 
  407 /*
  408  * This function is called when a read(2) is done to our device.
  409  * We process one mbuf from queue.
  410  */
  411 static int
  412 ngdread(struct cdev *dev, struct uio *uio, int flag)
  413 {
  414         priv_p  priv = (priv_p )dev->si_drv1;
  415         struct mbuf *m;
  416         int len, error = 0;
  417 
  418         DBG;
  419 
  420         /* get an mbuf */
  421         do {
  422                 IF_DEQUEUE(&priv->readq, m);
  423                 if (m == NULL) {
  424                         if (flag & IO_NDELAY)
  425                                 return (EWOULDBLOCK);
  426                         mtx_lock(&priv->ngd_mtx);
  427                         priv->flags |= NGDF_RWAIT;
  428                         if ((error = msleep(priv, &priv->ngd_mtx,
  429                             PDROP | PCATCH | (PZERO + 1),
  430                             "ngdread", 0)) != 0)
  431                                 return (error);
  432                 }
  433         } while (m == NULL);
  434 
  435         while (m && uio->uio_resid > 0 && error == 0) {
  436                 len = MIN(uio->uio_resid, m->m_len);
  437                 if (len != 0)
  438                         error = uiomove(mtod(m, void *), len, uio);
  439                 m = m_free(m);
  440         }
  441 
  442         if (m)
  443                 m_freem(m);
  444 
  445         return (error);
  446 }
  447 
  448 
  449 /*
  450  * This function is called when our device is written to.
  451  * We read the data from userland into mbuf chain and pass it to the remote hook.
  452  *
  453  */
  454 static int
  455 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
  456 {
  457         priv_p  priv = (priv_p )dev->si_drv1;
  458         struct mbuf *m;
  459         int error = 0;
  460 
  461         DBG;
  462 
  463         if (uio->uio_resid == 0)
  464                 return (0);
  465 
  466         if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
  467                 return (EIO);
  468 
  469         if ((m = m_uiotombuf(uio, M_DONTWAIT, 0, 0)) == NULL)
  470                 return (ENOBUFS);
  471 
  472         NG_SEND_DATA_ONLY(error, priv->hook, m);
  473 
  474         return (error);
  475 }
  476 
  477 /*
  478  * we are being polled/selected
  479  * check if there is data available for read
  480  */
  481 static int
  482 ngdpoll(struct cdev *dev, int events, struct thread *td)
  483 {
  484         priv_p  priv = (priv_p )dev->si_drv1;
  485         int revents = 0;
  486 
  487         if (events & (POLLIN | POLLRDNORM) &&
  488             !IFQ_IS_EMPTY(&priv->readq))
  489                 revents |= events & (POLLIN | POLLRDNORM);
  490 
  491         return (revents);
  492 }

Cache object: d38806386754164889bc814e9bc75904


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