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  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
    5  * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   26  *
   27  * Netgraph "device" node
   28  *
   29  * This node presents a /dev/ngd%d device that interfaces to an other
   30  * netgraph node.
   31  *
   32  * $FreeBSD: stable/12/sys/netgraph/ng_device.c 326272 2017-11-27 15:23:17Z pfg $
   33  *
   34  */
   35 
   36 #if 0
   37 #define DBG do { printf("ng_device: %s\n", __func__ ); } while (0)
   38 #else
   39 #define DBG do {} while (0)
   40 #endif
   41 
   42 #include <sys/param.h>
   43 #include <sys/conf.h>
   44 #include <sys/ioccom.h>
   45 #include <sys/kernel.h>
   46 #include <sys/malloc.h>
   47 #include <sys/mbuf.h>
   48 #include <sys/poll.h>
   49 #include <sys/queue.h>
   50 #include <sys/socket.h>
   51 #include <sys/systm.h>
   52 #include <sys/uio.h>
   53 #include <sys/vnode.h>
   54 
   55 #include <net/if.h>
   56 #include <net/if_var.h>
   57 #include <netinet/in.h>
   58 #include <netinet/in_systm.h>
   59 #include <netinet/ip.h>
   60 
   61 #include <netgraph/ng_message.h>
   62 #include <netgraph/netgraph.h>
   63 #include <netgraph/ng_device.h>
   64 
   65 #define ERROUT(x) do { error = (x); goto done; } while (0)
   66 
   67 /* Netgraph methods */
   68 static int              ng_device_mod_event(module_t, int, void *);
   69 static ng_constructor_t ng_device_constructor;
   70 static ng_rcvmsg_t      ng_device_rcvmsg;
   71 static ng_shutdown_t    ng_device_shutdown;
   72 static ng_newhook_t     ng_device_newhook;
   73 static ng_rcvdata_t     ng_device_rcvdata;
   74 static ng_disconnect_t  ng_device_disconnect;
   75 
   76 /* Netgraph type */
   77 static struct ng_type ngd_typestruct = {
   78         .version =      NG_ABI_VERSION,
   79         .name =         NG_DEVICE_NODE_TYPE,
   80         .mod_event =    ng_device_mod_event,
   81         .constructor =  ng_device_constructor,
   82         .rcvmsg =       ng_device_rcvmsg,
   83         .shutdown =     ng_device_shutdown,
   84         .newhook =      ng_device_newhook,
   85         .rcvdata =      ng_device_rcvdata,
   86         .disconnect =   ng_device_disconnect,
   87 };
   88 NETGRAPH_INIT(device, &ngd_typestruct);
   89 
   90 /* per node data */
   91 struct ngd_private {
   92         struct  ifqueue readq;
   93         struct  ng_node *node;
   94         struct  ng_hook *hook;
   95         struct  cdev    *ngddev;
   96         struct  mtx     ngd_mtx;
   97         int             unit;
   98         uint16_t        flags;
   99 #define NGDF_OPEN       0x0001
  100 #define NGDF_RWAIT      0x0002
  101 };
  102 typedef struct ngd_private *priv_p;
  103 
  104 /* unit number allocator entity */
  105 static struct unrhdr *ngd_unit;
  106 
  107 /* Maximum number of NGD devices */
  108 #define MAX_NGD 999
  109 
  110 static d_close_t ngdclose;
  111 static d_open_t ngdopen;
  112 static d_read_t ngdread;
  113 static d_write_t ngdwrite;
  114 #if 0
  115 static d_ioctl_t ngdioctl;
  116 #endif
  117 static d_poll_t ngdpoll;
  118 
  119 static struct cdevsw ngd_cdevsw = {
  120         .d_version =    D_VERSION,
  121         .d_open =       ngdopen,
  122         .d_close =      ngdclose,
  123         .d_read =       ngdread,
  124         .d_write =      ngdwrite,
  125 #if 0
  126         .d_ioctl =      ngdioctl,
  127 #endif
  128         .d_poll =       ngdpoll,
  129         .d_name =       NG_DEVICE_DEVNAME,
  130 };
  131 
  132 /******************************************************************************
  133  *  Netgraph methods
  134  ******************************************************************************/
  135 
  136 /*
  137  * Handle loading and unloading for this node type.
  138  */
  139 static int
  140 ng_device_mod_event(module_t mod, int event, void *data)
  141 {
  142         int error = 0;
  143 
  144         switch (event) {
  145         case MOD_LOAD:
  146                 ngd_unit = new_unrhdr(0, MAX_NGD, NULL);
  147                 break;
  148         case MOD_UNLOAD:
  149                 delete_unrhdr(ngd_unit);
  150                 break;
  151         default:
  152                 error = EOPNOTSUPP;
  153                 break;
  154         }
  155         return (error);
  156 }
  157 
  158 /*
  159  * create new node
  160  */
  161 static int
  162 ng_device_constructor(node_p node)
  163 {
  164         priv_p  priv;
  165 
  166         DBG;
  167 
  168         priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
  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, 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         const char *dn;
  209         int error = 0;
  210 
  211         NGI_GET_MSG(item, msg);
  212 
  213         if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
  214                 switch (msg->header.cmd) {
  215                 case NGM_DEVICE_GET_DEVNAME:
  216                         /* XXX: Fix when MAX_NGD us bigger */
  217                         NG_MKRESPONSE(resp, msg,
  218                             strlen(NG_DEVICE_DEVNAME) + 4, M_NOWAIT);
  219 
  220                         if (resp == NULL)
  221                                 ERROUT(ENOMEM);
  222 
  223                         dn = devtoname(priv->ngddev);
  224                         strlcpy((char *)resp->data, dn, strlen(dn) + 1);
  225                         break;
  226 
  227                 default:
  228                         error = EINVAL;
  229                         break;
  230                 }
  231         } else
  232                 error = EINVAL;
  233 
  234 done:
  235         NG_RESPOND_MSG(error, node, item, resp);
  236         NG_FREE_MSG(msg);
  237         return (error);
  238 }
  239 
  240 /*
  241  * Accept incoming hook. We support only one hook per node.
  242  */
  243 static int
  244 ng_device_newhook(node_p node, hook_p hook, const char *name)
  245 {
  246         priv_p priv = NG_NODE_PRIVATE(node);
  247 
  248         DBG;
  249 
  250         /* We have only one hook per node */
  251         if (priv->hook != NULL)
  252                 return (EISCONN);
  253 
  254         priv->hook = hook;
  255 
  256         return(0);
  257 }
  258 
  259 /*
  260  * Receive data from hook, write it to device.
  261  */
  262 static int
  263 ng_device_rcvdata(hook_p hook, item_p item)
  264 {
  265         priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  266         struct mbuf *m;
  267 
  268         DBG;
  269 
  270         NGI_GET_M(item, m);
  271         NG_FREE_ITEM(item);
  272 
  273         IF_LOCK(&priv->readq);
  274         if (_IF_QFULL(&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_NOWAIT, 0, 0, M_PKTHDR)) == 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 }

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