sys/netgraph/UI/ng_UI.c

   1
   2 /*
   3  * ng_UI.c
   4  *
   5  * Copyright (c) 1996-1999 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Julian Elischer <julian@freebsd.org>
  38  *
  39  * $FreeBSD: src/sys/netgraph/ng_UI.c,v 1.6.2.2 2000/10/24 18:36:44 julian Exp $
  40  * $Whistle: ng_UI.c,v 1.14 1999/11/01 09:24:51 julian Exp $
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/errno.h>
  46 #include <sys/kernel.h>
  47 #include <sys/malloc.h>
  48 #include <sys/mbuf.h>
  49
  50 #include <netgraph/ng_message.h>
  51 #include <netgraph/netgraph.h>
  52 #include "ng_UI.h"
  53
  54 /*
  55  * DEFINITIONS
  56  */
  57
  58 /* Everything, starting with sdlc on has defined UI as 0x03 */
  59 #define HDLC_UI 0x03
  60
  61 /* Node private data */
  62 struct ng_UI_private {
  63         hook_p  downlink;
  64         hook_p  uplink;
  65 };
  66 typedef struct ng_UI_private *priv_p;
  67
  68 /* Netgraph node methods */
  69 static ng_constructor_t ng_UI_constructor;
  70 static ng_rcvmsg_t      ng_UI_rcvmsg;
  71 static ng_shutdown_t    ng_UI_rmnode;
  72 static ng_newhook_t     ng_UI_newhook;
  73 static ng_rcvdata_t     ng_UI_rcvdata;
  74 static ng_disconnect_t  ng_UI_disconnect;
  75
  76 /* Node type descriptor */
  77 static struct ng_type typestruct = {
  78         NG_VERSION,
  79         NG_UI_NODE_TYPE,
  80         NULL,
  81         ng_UI_constructor,
  82         ng_UI_rcvmsg,
  83         ng_UI_rmnode,
  84         ng_UI_newhook,
  85         NULL,
  86         NULL,
  87         ng_UI_rcvdata,
  88         ng_UI_rcvdata,
  89         ng_UI_disconnect,
  90         NULL
  91 };
  92 NETGRAPH_INIT(UI, &typestruct);
  93
  94 /************************************************************************
  95                         NETGRAPH NODE STUFF
  96  ************************************************************************/
  97
  98 /*
  99  * Create a newborn node. We start with an implicit reference.
 100  */
 101
 102 static int
 103 ng_UI_constructor(node_p *nodep)
 104 {
 105         priv_p  priv;
 106         int     error;
 107
 108         /* Allocate private structure */
 109         priv = kmalloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
 110         if (priv == NULL)
 111                 return (ENOMEM);
 112
 113         /* Call generic node constructor */
 114         if ((error = ng_make_node_common(&typestruct, nodep))) {
 115                 kfree(priv, M_NETGRAPH);
 116                 return (error);
 117         }
 118         (*nodep)->private = priv;
 119
 120         /* Done */
 121         return (0);
 122 }
 123
 124 /*
 125  * Give our ok for a hook to be added
 126  */
 127 static int
 128 ng_UI_newhook(node_p node, hook_p hook, const char *name)
 129 {
 130         const priv_p priv = node->private;
 131
 132         if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
 133                 if (priv->downlink)
 134                         return (EISCONN);
 135                 priv->downlink = hook;
 136         } else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
 137                 if (priv->uplink)
 138                         return (EISCONN);
 139                 priv->uplink = hook;
 140         } else
 141                 return (EINVAL);
 142         return (0);
 143 }
 144
 145 /*
 146  * Receive a control message
 147  */
 148 static int
 149 ng_UI_rcvmsg(node_p node, struct ng_mesg *msg,
 150              const char *raddr, struct ng_mesg **rp)
 151 {
 152         kfree(msg, M_NETGRAPH);
 153         return (EINVAL);
 154 }
 155
 156 #define MAX_ENCAPS_HDR  1
 157 #define ERROUT(x)       do { error = (x); goto done; } while (0)
 158
 159 /*
 160  * Receive a data frame
 161  */
 162 static int
 163 ng_UI_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 164 {
 165         const node_p node = hook->node;
 166         const priv_p priv = node->private;
 167         int error = 0;
 168
 169         if (hook == priv->downlink) {
 170                 u_char *start, *ptr;
 171
 172                 if (!m || (m->m_len < MAX_ENCAPS_HDR
 173                     && !(m = m_pullup(m, MAX_ENCAPS_HDR))))
 174                         ERROUT(ENOBUFS);
 175                 ptr = start = mtod(m, u_char *);
 176
 177                 /* Must be UI frame */
 178                 if (*ptr++ != HDLC_UI)
 179                         ERROUT(0);
 180
 181                 m_adj(m, ptr - start);
 182                 NG_SEND_DATA(error, priv->uplink, m, meta);     /* m -> NULL */
 183         } else if (hook == priv->uplink) {
 184                 M_PREPEND(m, 1, M_NOWAIT);      /* Prepend IP NLPID */
 185                 if (!m)
 186                         ERROUT(ENOBUFS);
 187                 mtod(m, u_char *)[0] = HDLC_UI;
 188                 NG_SEND_DATA(error, priv->downlink, m, meta);   /* m -> NULL */
 189         } else
 190                 panic(__func__);
 191
 192 done:
 193         NG_FREE_DATA(m, meta);  /* does nothing if m == NULL */
 194         return (error);
 195 }
 196
 197 /*
 198  * Shutdown node
 199  */
 200 static int
 201 ng_UI_rmnode(node_p node)
 202 {
 203         const priv_p priv = node->private;
 204
 205         /* Take down netgraph node */
 206         node->flags |= NG_INVALID;
 207         ng_cutlinks(node);
 208         ng_unname(node);
 209         bzero(priv, sizeof(*priv));
 210         kfree(priv, M_NETGRAPH);
 211         node->private = NULL;
 212         ng_unref(node);
 213         return (0);
 214 }
 215
 216 /*
 217  * Hook disconnection
 218  */
 219 static int
 220 ng_UI_disconnect(hook_p hook)
 221 {
 222         const priv_p priv = hook->node->private;
 223
 224         if (hook->node->numhooks == 0)
 225                 ng_rmnode(hook->node);
 226         else if (hook == priv->downlink)
 227                 priv->downlink = NULL;
 228         else if (hook == priv->uplink)
 229                 priv->uplink = NULL;
 230         else
 231                 panic(__func__);
 232         return (0);
 233 }
 234