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