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: releng/10.0/sys/netgraph/ng_device.c 243882 2012-12-05 08:04:20Z glebius $
   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         priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
  167 
  168         /* Allocate unit number */
  169         priv->unit = alloc_unr(ngd_unit);
  170 
  171         /* Initialize mutexes and queue */
  172         mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
  173         mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
  174         IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
  175 
  176         /* Link everything together */
  177         NG_NODE_SET_PRIVATE(node, priv);
  178         priv->node = node;
  179 
  180         priv->ngddev = make_dev(&ngd_cdevsw, priv->unit, UID_ROOT,
  181             GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
  182         if(priv->ngddev == NULL) {
  183                 printf("%s(): make_dev() failed\n",__func__);
  184                 mtx_destroy(&priv->ngd_mtx);
  185                 mtx_destroy(&priv->readq.ifq_mtx);
  186                 free_unr(ngd_unit, priv->unit);
  187                 free(priv, M_NETGRAPH);
  188                 return(EINVAL);
  189         }
  190         /* XXX: race here? */
  191         priv->ngddev->si_drv1 = priv;
  192 
  193         return(0);
  194 }
  195 
  196 /*
  197  * Process control message.
  198  */
  199 
  200 static int
  201 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
  202 {
  203         const priv_p priv = NG_NODE_PRIVATE(node);
  204         struct ng_mesg *msg;
  205         struct ng_mesg *resp = NULL;
  206         const char *dn;
  207         int error = 0;
  208 
  209         NGI_GET_MSG(item, msg);
  210 
  211         if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
  212                 switch (msg->header.cmd) {
  213                 case NGM_DEVICE_GET_DEVNAME:
  214                         /* XXX: Fix when MAX_NGD us bigger */
  215                         NG_MKRESPONSE(resp, msg,
  216                             strlen(NG_DEVICE_DEVNAME) + 4, M_NOWAIT);
  217 
  218                         if (resp == NULL)
  219                                 ERROUT(ENOMEM);
  220 
  221                         dn = devtoname(priv->ngddev);
  222                         strlcpy((char *)resp->data, dn, strlen(dn) + 1);
  223                         break;
  224 
  225                 default:
  226                         error = EINVAL;
  227                         break;
  228                 }
  229         } else
  230                 error = EINVAL;
  231 
  232 done:
  233         NG_RESPOND_MSG(error, node, item, resp);
  234         NG_FREE_MSG(msg);
  235         return (error);
  236 }
  237 
  238 /*
  239  * Accept incoming hook. We support only one hook per node.
  240  */
  241 static int
  242 ng_device_newhook(node_p node, hook_p hook, const char *name)
  243 {
  244         priv_p priv = NG_NODE_PRIVATE(node);
  245 
  246         DBG;
  247 
  248         /* We have only one hook per node */
  249         if (priv->hook != NULL)
  250                 return (EISCONN);
  251 
  252         priv->hook = hook;
  253 
  254         return(0);
  255 }
  256 
  257 /*
  258  * Receive data from hook, write it to device.
  259  */
  260 static int
  261 ng_device_rcvdata(hook_p hook, item_p item)
  262 {
  263         priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  264         struct mbuf *m;
  265 
  266         DBG;
  267 
  268         NGI_GET_M(item, m);
  269         NG_FREE_ITEM(item);
  270 
  271         IF_LOCK(&priv->readq);
  272         if (_IF_QFULL(&priv->readq)) {
  273                 _IF_DROP(&priv->readq);
  274                 IF_UNLOCK(&priv->readq);
  275                 NG_FREE_M(m);
  276                 return (ENOBUFS);
  277         }
  278 
  279         _IF_ENQUEUE(&priv->readq, m);
  280         IF_UNLOCK(&priv->readq);
  281         mtx_lock(&priv->ngd_mtx);
  282         if (priv->flags & NGDF_RWAIT) {
  283                 priv->flags &= ~NGDF_RWAIT;
  284                 wakeup(priv);
  285         }
  286         mtx_unlock(&priv->ngd_mtx);
  287 
  288         return(0);
  289 }
  290 
  291 /*
  292  * Removal of the hook destroys the node.
  293  */
  294 static int
  295 ng_device_disconnect(hook_p hook)
  296 {
  297         priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  298 
  299         DBG;
  300 
  301         destroy_dev(priv->ngddev);
  302         mtx_destroy(&priv->ngd_mtx);
  303 
  304         IF_DRAIN(&priv->readq);
  305         mtx_destroy(&(priv)->readq.ifq_mtx);
  306 
  307         free_unr(ngd_unit, priv->unit);
  308 
  309         free(priv, M_NETGRAPH);
  310 
  311         ng_rmnode_self(NG_HOOK_NODE(hook));
  312 
  313         return(0);
  314 }
  315 
  316 /*
  317  * Node shutdown. Everything is already done in disconnect method.
  318  */
  319 static int
  320 ng_device_shutdown(node_p node)
  321 {
  322         NG_NODE_UNREF(node);
  323         return (0);
  324 }
  325 
  326 /******************************************************************************
  327  *  Device methods
  328  ******************************************************************************/
  329 
  330 /*
  331  * the device is opened
  332  */
  333 static int
  334 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
  335 {
  336         priv_p  priv = (priv_p )dev->si_drv1;
  337 
  338         DBG;
  339 
  340         mtx_lock(&priv->ngd_mtx);
  341         priv->flags |= NGDF_OPEN;
  342         mtx_unlock(&priv->ngd_mtx);
  343 
  344         return(0);
  345 }
  346 
  347 /*
  348  * the device is closed
  349  */
  350 static int
  351 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
  352 {
  353         priv_p  priv = (priv_p )dev->si_drv1;
  354 
  355         DBG;
  356         mtx_lock(&priv->ngd_mtx);
  357         priv->flags &= ~NGDF_OPEN;
  358         mtx_unlock(&priv->ngd_mtx);
  359 
  360         return(0);
  361 }
  362 
  363 #if 0   /*
  364          * The ioctl is transformed into netgraph control message.
  365          * We do not process them, yet.
  366          */
  367 /*
  368  * process ioctl
  369  *
  370  * they are translated into netgraph messages and passed on
  371  *
  372  */
  373 static int
  374 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
  375 {
  376         struct ngd_softc *sc = &ngd_softc;
  377         struct ngd_connection * connection = NULL;
  378         struct ngd_connection * tmp;
  379         int error = 0;
  380         struct ng_mesg *msg;
  381         struct ngd_param_s * datap;
  382 
  383         DBG;
  384 
  385         NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
  386                         M_NOWAIT);
  387         if (msg == NULL) {
  388                 printf("%s(): msg == NULL\n",__func__);
  389                 goto nomsg;
  390         }
  391 
  392         /* pass the ioctl data into the ->data area */
  393         datap = (struct ngd_param_s *)msg->data;
  394         datap->p = addr;
  395 
  396         NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
  397         if(error)
  398                 printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
  399 
  400 nomsg:
  401 
  402         return(0);
  403 }
  404 #endif /* if 0 */
  405 
  406 /*
  407  * This function is called when a read(2) is done to our device.
  408  * We process one mbuf from queue.
  409  */
  410 static int
  411 ngdread(struct cdev *dev, struct uio *uio, int flag)
  412 {
  413         priv_p  priv = (priv_p )dev->si_drv1;
  414         struct mbuf *m;
  415         int len, error = 0;
  416 
  417         DBG;
  418 
  419         /* get an mbuf */
  420         do {
  421                 IF_DEQUEUE(&priv->readq, m);
  422                 if (m == NULL) {
  423                         if (flag & IO_NDELAY)
  424                                 return (EWOULDBLOCK);
  425                         mtx_lock(&priv->ngd_mtx);
  426                         priv->flags |= NGDF_RWAIT;
  427                         if ((error = msleep(priv, &priv->ngd_mtx,
  428                             PDROP | PCATCH | (PZERO + 1),
  429                             "ngdread", 0)) != 0)
  430                                 return (error);
  431                 }
  432         } while (m == NULL);
  433 
  434         while (m && uio->uio_resid > 0 && error == 0) {
  435                 len = MIN(uio->uio_resid, m->m_len);
  436                 if (len != 0)
  437                         error = uiomove(mtod(m, void *), len, uio);
  438                 m = m_free(m);
  439         }
  440 
  441         if (m)
  442                 m_freem(m);
  443 
  444         return (error);
  445 }
  446 
  447 
  448 /*
  449  * This function is called when our device is written to.
  450  * We read the data from userland into mbuf chain and pass it to the remote hook.
  451  *
  452  */
  453 static int
  454 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
  455 {
  456         priv_p  priv = (priv_p )dev->si_drv1;
  457         struct mbuf *m;
  458         int error = 0;
  459 
  460         DBG;
  461 
  462         if (uio->uio_resid == 0)
  463                 return (0);
  464 
  465         if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
  466                 return (EIO);
  467 
  468         if ((m = m_uiotombuf(uio, M_NOWAIT, 0, 0, M_PKTHDR)) == NULL)
  469                 return (ENOBUFS);
  470 
  471         NG_SEND_DATA_ONLY(error, priv->hook, m);
  472 
  473         return (error);
  474 }
  475 
  476 /*
  477  * we are being polled/selected
  478  * check if there is data available for read
  479  */
  480 static int
  481 ngdpoll(struct cdev *dev, int events, struct thread *td)
  482 {
  483         priv_p  priv = (priv_p )dev->si_drv1;
  484         int revents = 0;
  485 
  486         if (events & (POLLIN | POLLRDNORM) &&
  487             !IFQ_IS_EMPTY(&priv->readq))
  488                 revents |= events & (POLLIN | POLLRDNORM);
  489 
  490         return (revents);
  491 }

Cache object: 73f35ca40e0c75d17b9b533562e738c3


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