sys/netgraph7/ng_UI.c

   1 /*
   2  * ng_UI.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: src/sys/netgraph/ng_UI.c,v 1.20 2005/01/07 01:45:39 imp Exp $
  41  * $DragonFly: src/sys/netgraph7/ng_UI.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
  42  * $Whistle: ng_UI.c,v 1.14 1999/11/01 09:24:51 julian Exp $
  43  */
  44
  45 #include <sys/param.h>
  46 #include <sys/systm.h>
  47 #include <sys/errno.h>
  48 #include <sys/kernel.h>
  49 #include <sys/malloc.h>
  50 #include <sys/mbuf.h>
  51 #include <sys/errno.h>
  52
  53
  54 #include "ng_message.h"
  55 #include "netgraph.h"
  56 #include "ng_UI.h"
  57
  58 /*
  59  * DEFINITIONS
  60  */
  61
  62 /* Everything, starting with sdlc on has defined UI as 0x03 */
  63 #define HDLC_UI 0x03
  64
  65 /* Node private data */
  66 struct ng_UI_private {
  67         hook_p  downlink;
  68         hook_p  uplink;
  69 };
  70 typedef struct ng_UI_private *priv_p;
  71
  72 /* Netgraph node methods */
  73 static ng_constructor_t ng_UI_constructor;
  74 static ng_rcvmsg_t      ng_UI_rcvmsg;
  75 static ng_shutdown_t    ng_UI_shutdown;
  76 static ng_newhook_t     ng_UI_newhook;
  77 static ng_rcvdata_t     ng_UI_rcvdata;
  78 static ng_disconnect_t  ng_UI_disconnect;
  79
  80 /* Node type descriptor */
  81 static struct ng_type typestruct = {
  82         .version =      NG_ABI_VERSION,
  83         .name =         NG_UI_NODE_TYPE,
  84         .constructor =  ng_UI_constructor,
  85         .rcvmsg =       ng_UI_rcvmsg,
  86         .shutdown =     ng_UI_shutdown,
  87         .newhook =      ng_UI_newhook,
  88         .rcvdata =      ng_UI_rcvdata,
  89         .disconnect =   ng_UI_disconnect,
  90 };
  91 NETGRAPH_INIT(UI, &typestruct);
  92
  93 /************************************************************************
  94                         NETGRAPH NODE STUFF
  95  ************************************************************************/
  96
  97 /*
  98  * Create a newborn node. We start with an implicit reference.
  99  */
 100
 101 static int
 102 ng_UI_constructor(node_p node)
 103 {
 104         priv_p  priv;
 105
 106         /* Allocate private structure */
 107         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_WAITOK | M_NULLOK | M_ZERO);
 108         if (priv == NULL) {
 109                 return (ENOMEM);
 110         }
 111         NG_NODE_SET_PRIVATE(node, priv);
 112         return (0);
 113 }
 114
 115 /*
 116  * Give our ok for a hook to be added
 117  */
 118 static int
 119 ng_UI_newhook(node_p node, hook_p hook, const char *name)
 120 {
 121         const priv_p priv = NG_NODE_PRIVATE(node);
 122
 123         if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
 124                 if (priv->downlink)
 125                         return (EISCONN);
 126                 priv->downlink = hook;
 127         } else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
 128                 if (priv->uplink)
 129                         return (EISCONN);
 130                 priv->uplink = hook;
 131         } else
 132                 return (EINVAL);
 133         return (0);
 134 }
 135
 136 /*
 137  * Receive a control message
 138  */
 139 static int
 140 ng_UI_rcvmsg(node_p node, item_p item, hook_p lasthook)
 141 {
 142         int     error;
 143         const priv_p priv = NG_NODE_PRIVATE(node);
 144         struct ng_mesg *msg;
 145
 146         msg = NGI_MSG(item); /* only peeking */
 147         if ((msg->header.typecookie == NGM_FLOW_COOKIE) && lasthook)  {
 148                 if (lasthook == priv->downlink) {
 149                         if (priv->uplink) {
 150                                 NG_FWD_ITEM_HOOK(error, item, priv->uplink);
 151                                 return (error);
 152                         }
 153                 } else {
 154                         if (priv->downlink) {
 155                                 NG_FWD_ITEM_HOOK(error, item, priv->downlink);
 156                                 return (error);
 157                         }
 158                 }
 159         }
 160
 161         NG_FREE_ITEM(item);
 162         return (EINVAL);
 163 }
 164
 165 #define MAX_ENCAPS_HDR  1
 166 #define ERROUT(x)       do { error = (x); goto done; } while (0)
 167
 168 /*
 169  * Receive a data frame
 170  */
 171 static int
 172 ng_UI_rcvdata(hook_p hook, item_p item)
 173 {
 174         const node_p node = NG_HOOK_NODE(hook);
 175         const priv_p priv = NG_NODE_PRIVATE(node);
 176         struct mbuf *m;
 177         int error = 0;
 178
 179         NGI_GET_M(item, m);
 180         if (hook == priv->downlink) {
 181                 u_char *start, *ptr;
 182
 183                 if (m->m_len < MAX_ENCAPS_HDR
 184                     && !(m = m_pullup(m, MAX_ENCAPS_HDR)))
 185                         ERROUT(ENOBUFS);
 186                 ptr = start = mtod(m, u_char *);
 187
 188                 /* Must be UI frame */
 189                 if (*ptr++ != HDLC_UI)
 190                         ERROUT(0);
 191
 192                 m_adj(m, ptr - start);
 193                 NG_FWD_NEW_DATA(error, item, priv->uplink, m);  /* m -> NULL */
 194         } else if (hook == priv->uplink) {
 195                 M_PREPEND(m, 1, MB_DONTWAIT);   /* Prepend IP NLPID */
 196                 if (!m)
 197                         ERROUT(ENOBUFS);
 198                 mtod(m, u_char *)[0] = HDLC_UI;
 199                 NG_FWD_NEW_DATA(error, item, priv->downlink, m);        /* m -> NULL */
 200         } else
 201                 panic(__func__);
 202
 203 done:
 204         NG_FREE_M(m);   /* does nothing if m == NULL */
 205         if (item)
 206                 NG_FREE_ITEM(item);
 207         return (error);
 208 }
 209
 210 /*
 211  * Shutdown node
 212  */
 213 static int
 214 ng_UI_shutdown(node_p node)
 215 {
 216         const priv_p priv = NG_NODE_PRIVATE(node);
 217
 218         /* Take down netgraph node */
 219         FREE(priv, M_NETGRAPH);
 220         NG_NODE_SET_PRIVATE(node, NULL);
 221         NG_NODE_UNREF(node);
 222         return (0);
 223 }
 224
 225 /*
 226  * Hook disconnection
 227  */
 228 static int
 229 ng_UI_disconnect(hook_p hook)
 230 {
 231         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 232
 233         if (hook == priv->downlink)
 234                 priv->downlink = NULL;
 235         else if (hook == priv->uplink)
 236                 priv->uplink = NULL;
 237         else
 238                 panic(__func__);
 239         /*
 240          * If we are not already shutting down,
 241          * and we have no more hooks, then DO shut down.
 242          */
 243         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 244         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 245                         ng_rmnode_self(NG_HOOK_NODE(hook));
 246         }
 247         return (0);
 248 }
 249