sys/netgraph/ng_ether_echo.c

   1 /*
   2  * ng_ether_echo.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 Elisher <julian@freebsd.org>
  39  * $Whistle: ng_echo.c,v 1.13 1999/11/01 09:24:51 julian Exp $
  40  */
  41
  42 /*
  43  * Netgraph "ether_echo" node
  44  *
  45  * This node simply bounces data and messages back to whence they came.
  46  * However it swaps the source and destination ether fields.
  47  * No testing is done!
  48  */
  49
  50 #include <sys/param.h>
  51 #include <sys/systm.h>
  52 #include <sys/kernel.h>
  53 #include <sys/malloc.h>
  54 #include <sys/mbuf.h>
  55 #include <netgraph/ng_message.h>
  56 #include <netgraph/netgraph.h>
  57 #include <netgraph/ng_ether_echo.h>
  58
  59 #include <net/ethernet.h>
  60
  61 /* Netgraph methods */
  62 static ng_constructor_t ngee_cons;
  63 static ng_rcvmsg_t      ngee_rcvmsg;
  64 static ng_rcvdata_t     ngee_rcvdata;
  65 static ng_disconnect_t  ngee_disconnect;
  66
  67 /* Netgraph type */
  68 static struct ng_type typestruct = {
  69         .version =      NG_ABI_VERSION,
  70         .name =         NG_ETHER_ECHO_NODE_TYPE,
  71         .constructor =  ngee_cons,
  72         .rcvmsg =       ngee_rcvmsg,
  73         .rcvdata =      ngee_rcvdata,
  74         .disconnect =   ngee_disconnect,
  75 };
  76 NETGRAPH_INIT(ether_echo, &typestruct);
  77
  78 static int
  79 ngee_cons(node_p node)
  80 {
  81         return (0);
  82 }
  83
  84 /*
  85  * Receive control message. We just bounce it back as a reply.
  86  */
  87 static int
  88 ngee_rcvmsg(node_p node, item_p item, hook_p lasthook)
  89 {
  90         struct ng_mesg *msg;
  91         int error = 0;
  92
  93         NGI_GET_MSG(item, msg);
  94         msg->header.flags |= NGF_RESP;
  95         NG_RESPOND_MSG(error, node, item, msg);
  96         return (error);
  97 }
  98
  99 /*
 100  * Receive data
 101  */
 102 static int
 103 ngee_rcvdata(hook_p hook, item_p item)
 104 {
 105         int error;
 106         struct mbuf *m;
 107
 108         struct ether_header *eh;
 109         struct ether_addr tmpaddr;
 110
 111         /* Make sure we have an entire header */
 112         NGI_GET_M(item, m);
 113         if (m->m_len < sizeof(*eh) ) {
 114                 m = m_pullup(m, sizeof(*eh));
 115                 if (m == NULL) {
 116                         NG_FREE_ITEM(item);
 117                         return(EINVAL);
 118                 }
 119         }
 120         eh = mtod(m, struct ether_header *);
 121
 122         /* swap the source and destination fields */
 123         bcopy(eh->ether_dhost, &tmpaddr, ETHER_ADDR_LEN);
 124         bcopy(eh->ether_shost, eh->ether_dhost, ETHER_ADDR_LEN);
 125         bcopy(&tmpaddr, eh->ether_shost, ETHER_ADDR_LEN);
 126
 127         NG_FWD_NEW_DATA(error, item, hook, m);
 128         return (error);
 129 }
 130
 131 /*
 132  * Removal of the last link destroys the nodeo
 133  */
 134 static int
 135 ngee_disconnect(hook_p hook)
 136 {
 137         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 138         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 139                 ng_rmnode_self(NG_HOOK_NODE(hook));
 140         }
 141         return (0);
 142 }