text: /*
   * ng_rfc1490.c
   */
  
  /*-
   * Copyright (c) 1996-1999 Whistle Communications, Inc.
   * All rights reserved.
   * 
   * Subject to the following obligations and disclaimer of warranty, use and
   * redistribution of this software, in source or object code forms, with or
   * without modifications are expressly permitted by Whistle Communications;
   * provided, however, that:
   * 1. Any and all reproductions of the source or object code must include the
   *    copyright notice above and the following disclaimer of warranties; and
   * 2. No rights are granted, in any manner or form, to use Whistle
   *    Communications, Inc. trademarks, including the mark "WHISTLE
   *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   *    such appears in the above copyright notice or in the software.
   * 
   * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   * OF SUCH DAMAGE.
   *
   * Author: Julian Elischer <julian@freebsd.org>
   *
   * $FreeBSD$
   * $Whistle: ng_rfc1490.c,v 1.22 1999/11/01 09:24:52 julian Exp $
   */
  
  /*
   * This node does RFC 1490 multiplexing.
   *
   * NOTE: RFC 1490 is updated by RFC 2427.
   */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/errno.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/mbuf.h>
  #include <sys/errno.h>
  #include <sys/socket.h>
  
  #include <net/if.h>
  #include <netinet/in.h>
  #include <netinet/if_ether.h>
  
  #include <netgraph/ng_message.h>
  #include <netgraph/netgraph.h>
  #include <netgraph/ng_parse.h>
  #include <netgraph/ng_rfc1490.h>
  
  /*
   * DEFINITIONS
   */
  
  /* Q.922 stuff -- see RFC 1490 */
  #define HDLC_UI		0x03
  
  #define NLPID_IP	0xCC
  #define NLPID_PPP	0xCF
  #define NLPID_SNAP	0x80
  #define NLPID_Q933	0x08
  #define NLPID_CLNP	0x81
  #define NLPID_ESIS	0x82
  #define NLPID_ISIS	0x83
  
  #define ERROUT(x)	do { error = (x); goto done; } while (0)
  
  /* Encapsulation methods we understand */
  enum {
  	NG_RFC1490_ENCAP_IETF_IP = 1,	/* see RFC2427, chapter 7, table 1 */
  	NG_RFC1490_ENCAP_IETF_SNAP,	/* see RFC2427, chapter 7, table 2 */
  	NG_RFC1490_ENCAP_CISCO,		/* Cisco's proprietary encapsulation */
  };
  
  struct ng_rfc1490_encap_t {
  	u_int8_t	method;
  	const char	*name;
  };
  
  static const struct ng_rfc1490_encap_t ng_rfc1490_encaps[] = {
  	{ NG_RFC1490_ENCAP_IETF_IP,	"ietf-ip" },
  	{ NG_RFC1490_ENCAP_IETF_SNAP,	"ietf-snap" },
  	{ NG_RFC1490_ENCAP_CISCO,	"cisco" },
  	{ 0, NULL},
  };
  
  /* Node private data */
  struct ng_rfc1490_private {
  	hook_p  downlink;
  	hook_p  ppp;
  	hook_p  inet;
  	hook_p  ethernet;
  	const struct ng_rfc1490_encap_t *enc;
  };
  typedef struct ng_rfc1490_private *priv_p;
  
  /* Netgraph node methods */
  static ng_constructor_t	ng_rfc1490_constructor;
  static ng_rcvmsg_t	ng_rfc1490_rcvmsg;
  static ng_shutdown_t	ng_rfc1490_shutdown;
  static ng_newhook_t	ng_rfc1490_newhook;
  static ng_rcvdata_t	ng_rfc1490_rcvdata;
  static ng_disconnect_t	ng_rfc1490_disconnect;
  
  /* List of commands and how to convert arguments to/from ASCII */
  static const struct ng_cmdlist ng_rfc1490_cmds[] = {
  	{
  	  NGM_RFC1490_COOKIE,
  	  NGM_RFC1490_SET_ENCAP,
  	  "setencap",
  	  &ng_parse_string_type,
  	  NULL
  	},
  	{
  	  NGM_RFC1490_COOKIE,
  	  NGM_RFC1490_GET_ENCAP,
  	  "getencap",
  	  NULL,
  	  &ng_parse_string_type
  	},
  	{ 0 }
  };
  
  /* Node type descriptor */
  static struct ng_type typestruct = {
  	.version =	NG_ABI_VERSION,
  	.name =		NG_RFC1490_NODE_TYPE,
  	.constructor =	ng_rfc1490_constructor,
  	.rcvmsg =	ng_rfc1490_rcvmsg,
  	.shutdown =	ng_rfc1490_shutdown,
  	.newhook =	ng_rfc1490_newhook,
  	.rcvdata =	ng_rfc1490_rcvdata,
  	.disconnect =	ng_rfc1490_disconnect,
  	.cmdlist =	ng_rfc1490_cmds,
  };
  NETGRAPH_INIT(rfc1490, &typestruct);
  
  /************************************************************************
  			NETGRAPH NODE STUFF
   ************************************************************************/
  
  /*
   * Node constructor
   */
  static int
  ng_rfc1490_constructor(node_p node)
  {
  	priv_p priv;
  
  	/* Allocate private structure */
  	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
  
  	/* Initialize to default encapsulation method - ietf-ip */
  	priv->enc = ng_rfc1490_encaps;
  
  	NG_NODE_SET_PRIVATE(node, priv);
  
  	/* Done */
  	return (0);
  }
  
  /*
   * Give our ok for a hook to be added
   */
  static int
  ng_rfc1490_newhook(node_p node, hook_p hook, const char *name)
  {
  	const priv_p priv = NG_NODE_PRIVATE(node);
  
  	if (!strcmp(name, NG_RFC1490_HOOK_DOWNSTREAM)) {
  		if (priv->downlink)
  			return (EISCONN);
  		priv->downlink = hook;
  	} else if (!strcmp(name, NG_RFC1490_HOOK_PPP)) {
  		if (priv->ppp)
  			return (EISCONN);
  		priv->ppp = hook;
  	} else if (!strcmp(name, NG_RFC1490_HOOK_INET)) {
  		if (priv->inet)
  			return (EISCONN);
  		priv->inet = hook;
  	} else if (!strcmp(name, NG_RFC1490_HOOK_ETHERNET)) {
  		if (priv->ethernet)
  			return (EISCONN);
  		priv->ethernet = hook;
  	} else
  		return (EINVAL);
  	return (0);
  }
  
  /*
   * Receive a control message.
   */
  static int
  ng_rfc1490_rcvmsg(node_p node, item_p item, hook_p lasthook)
  {
  	const priv_p priv = NG_NODE_PRIVATE(node);
  	struct ng_mesg *msg;
  	struct ng_mesg *resp = NULL;
  	int error = 0;
  
  	NGI_GET_MSG(item, msg);
  
  	if (msg->header.typecookie == NGM_RFC1490_COOKIE) {
  		switch (msg->header.cmd) {
  		case NGM_RFC1490_SET_ENCAP:
  		{
  			const struct ng_rfc1490_encap_t *enc;
  			char *s;
  			size_t len;
  
  			if (msg->header.arglen == 0)
  				ERROUT(EINVAL);
  
  			s = (char *)msg->data;
  			len = msg->header.arglen - 1;
  
  			/* Search for matching encapsulation method */
  			for (enc = ng_rfc1490_encaps; enc->method != 0; enc++ )
  				if ((strlen(enc->name) == len) &&
  				    !strncmp(enc->name, s, len))
  					break;	/* found */
  
  			if (enc->method != 0)
  				priv->enc = enc;
  			else
  				error = EINVAL;
  			break;
  		}
  		case NGM_RFC1490_GET_ENCAP:
  
  			NG_MKRESPONSE(resp, msg, strlen(priv->enc->name) + 1, M_NOWAIT);
  			if (resp == NULL)
  				ERROUT(ENOMEM);
  
  			strlcpy((char *)resp->data, priv->enc->name,
  			    strlen(priv->enc->name) + 1);
  			break;
  
  		default:
  			error = EINVAL;
  			break;
  		}
  	} else
  		error = EINVAL;
  
  done:
  	NG_RESPOND_MSG(error, node, item, resp);
  	NG_FREE_MSG(msg);
  	return (error);
  }
  
  /*
   * Receive data on a hook and encapsulate according to RFC 1490.
   * Only those nodes marked (*) are supported by this routine so far.
   *
   *                            Q.922 control
   *                                 |
   *                                 |
   *            ---------------------------------------------------------------------
   *            | 0x03                                     |                        |
   *           UI                                       I Frame                   Cisco
   *            |                                          |                  Encapsulation
   *      ---------------------------------         --------------                  |
   *      | 0x08  | 0x81  |0xCC   |0xCF   | 0x00    |..01....    |..10....   --------------
   *      |       |       |       |       | 0x80    |            |           |0x800       |
   *     Q.933   CLNP    IP(*)   PPP(*)  SNAP     ISO 8208    ISO 8208       |            |
   *      |                    (rfc1973)  |       Modulo 8    Modulo 128     IP(*)     Others
   *      |                               |
   *      --------------------           OUI
   *      |                  |            |
   *     L2 ID              L3 ID      -------------------------
   *      |               User         |00-80-C2               |00-00-00
   *      |               specified    |                       |
   *      |               0x70        PID                     Ethertype
   *      |                            |                       |
   *      -------------------        -----------------...     ----------
   *      |0x51 |0x4E |     |0x4C    |0x7      |0xB  |        |0x806   |
   *      |     |     |     |        |         |     |        |        |
   *     7776  Q.922 Others 802.2   802.3(*)  802.6 Others    IP(*)   Others
   *
   *
   */
  
  #define MAX_ENCAPS_HDR	8
  #define OUICMP(P,A,B,C)	((P)[0]==(A) && (P)[1]==(B) && (P)[2]==(C))
  
  static int
  ng_rfc1490_rcvdata(hook_p hook, item_p item)
  {
  	const node_p node = NG_HOOK_NODE(hook);
  	const priv_p priv = NG_NODE_PRIVATE(node);
  	int error = 0;
  	struct mbuf *m;
  
  	NGI_GET_M(item, m);
  	if (hook == priv->downlink) {
  		const u_char *start;
  		const u_char *ptr;
  
  		if (m->m_len < MAX_ENCAPS_HDR
  		    && !(m = m_pullup(m, MAX_ENCAPS_HDR)))
  			ERROUT(ENOBUFS);
  		ptr = start = mtod(m, const u_char *);
  
  		if (priv->enc->method == NG_RFC1490_ENCAP_CISCO)
  			goto switch_on_etype;
  
  		/* Must be UI frame */
  		if (*ptr++ != HDLC_UI)
  			ERROUT(0);
  
  		/* Eat optional zero pad byte */
  		if (*ptr == 0x00)
  			ptr++;
  
  		/* Multiplex on NLPID */
  		switch (*ptr++) {
  		case NLPID_SNAP:
  			if (OUICMP(ptr, 0, 0, 0)) {	/* It's an ethertype */
  				u_int16_t etype;
  
  				ptr += 3;
  switch_on_etype:		etype = ntohs(*((const u_int16_t *)ptr));
  				ptr += 2;
  				m_adj(m, ptr - start);
  				switch (etype) {
  				case ETHERTYPE_IP:
  					NG_FWD_NEW_DATA(error, item,
  					    priv->inet, m);
  					break;
  				case ETHERTYPE_ARP:
  				case ETHERTYPE_REVARP:
  				default:
  					ERROUT(0);
  				}
  			} else if (OUICMP(ptr, 0x00, 0x80, 0xc2)) {
  				/* 802.1 bridging */
  				ptr += 3;
  				if (*ptr++ != 0x00)
  					ERROUT(0);	/* unknown PID octet 0 */
  				if (*ptr++ != 0x07)
  					ERROUT(0);	/* not FCS-less 802.3 */
  				m_adj(m, ptr - start);
  				NG_FWD_NEW_DATA(error, item, priv->ethernet, m);
  			} else	/* Other weird stuff... */
  				ERROUT(0);
  			break;
  		case NLPID_IP:
  			m_adj(m, ptr - start);
  			NG_FWD_NEW_DATA(error, item, priv->inet, m);
  			break;
  		case NLPID_PPP:
  			m_adj(m, ptr - start);
  			NG_FWD_NEW_DATA(error, item, priv->ppp, m);
  			break;
  		case NLPID_Q933:
  		case NLPID_CLNP:
  		case NLPID_ESIS:
  		case NLPID_ISIS:
  			ERROUT(0);
  		default:	/* Try PPP (see RFC 1973) */
  			ptr--;	/* NLPID becomes PPP proto */
  			if ((*ptr & 0x01) == 0x01)
  				ERROUT(0);
  			m_adj(m, ptr - start);
  			NG_FWD_NEW_DATA(error, item, priv->ppp, m);
  			break;
  		}
  	} else if (hook == priv->ppp) {
  		M_PREPEND(m, 2, M_NOWAIT);	/* Prepend PPP NLPID */
  		if (!m)
  			ERROUT(ENOBUFS);
  		mtod(m, u_char *)[0] = HDLC_UI;
  		mtod(m, u_char *)[1] = NLPID_PPP;
  		NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  	} else if (hook == priv->inet) {
  		switch (priv->enc->method) {
  		case NG_RFC1490_ENCAP_IETF_IP:
  			M_PREPEND(m, 2, M_NOWAIT);	/* Prepend IP NLPID */
  			if (!m)
  				ERROUT(ENOBUFS);
  			mtod(m, u_char *)[0] = HDLC_UI;
  			mtod(m, u_char *)[1] = NLPID_IP;
  			break;
  		case NG_RFC1490_ENCAP_IETF_SNAP:
  			/*
  			 *  According to RFC2427 frame should begin with
  			 *  HDLC_UI  PAD  NLIPID  OUI      PID
  			 *  03      00   80      00 00 00  08 00
  			 */
  			M_PREPEND(m, 8, M_NOWAIT);
  			if (!m)
  				ERROUT(ENOBUFS);
  			mtod(m, u_char *)[0] = HDLC_UI;
  			mtod(m, u_char *)[1] = 0x00;			/* PAD */
  			mtod(m, u_char *)[2] = NLPID_SNAP;
  			bzero((char *)(mtod(m, u_char *) + 3), 3);	/* OUI 0-0-0 */
  			*((u_int16_t *)mtod(m, u_int16_t *) + 6/sizeof(u_int16_t))
  			    = htons(ETHERTYPE_IP);  /* PID */
  			break;
  		case NG_RFC1490_ENCAP_CISCO:
  			M_PREPEND(m, 2, M_NOWAIT);	/* Prepend IP ethertype */
  			if (!m)
  				ERROUT(ENOBUFS);
  			*((u_int16_t *)mtod(m, u_int16_t *)) = htons(ETHERTYPE_IP);
  			break;
  		}
  		NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  	} else if (hook == priv->ethernet) {
  		M_PREPEND(m, 8, M_NOWAIT);	/* Prepend NLPID, OUI, PID */
  		if (!m)
  			ERROUT(ENOBUFS);
  		mtod(m, u_char *)[0] = HDLC_UI;
  		mtod(m, u_char *)[1] = 0x00;		/* pad */
  		mtod(m, u_char *)[2] = NLPID_SNAP;
  		mtod(m, u_char *)[3] = 0x00;		/* OUI */
  		mtod(m, u_char *)[4] = 0x80;
  		mtod(m, u_char *)[5] = 0xc2;
  		mtod(m, u_char *)[6] = 0x00;		/* PID */
  		mtod(m, u_char *)[7] = 0x07;
  		NG_FWD_NEW_DATA(error, item, priv->downlink, m);
  	} else
  		panic("%s", __func__);
  
  done:
  	if (item)
  		NG_FREE_ITEM(item);
  	NG_FREE_M(m);
  	return (error);
  }
  
  /*
   * Nuke node
   */
  static int
  ng_rfc1490_shutdown(node_p node)
  {
  	const priv_p priv = NG_NODE_PRIVATE(node);
  
  	/* Take down netgraph node */
  	bzero(priv, sizeof(*priv));
  	free(priv, M_NETGRAPH);
  	NG_NODE_SET_PRIVATE(node, NULL);
  	NG_NODE_UNREF(node);		/* let the node escape */
  	return (0);
  }
  
  /*
   * Hook disconnection
   */
  static int
  ng_rfc1490_disconnect(hook_p hook)
  {
  	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
  
  	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
  	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
  		ng_rmnode_self(NG_HOOK_NODE(hook));
  	else if (hook == priv->downlink)
  		priv->downlink = NULL;
  	else if (hook == priv->inet)
  		priv->inet = NULL;
  	else if (hook == priv->ppp)
  		priv->ppp = NULL;
  	else if (hook == priv->ethernet)
  		priv->ethernet = NULL;
  	else
  		panic("%s", __func__);
  	return (0);
  }
  
  