mibII_nettomedia.c

/*
 * Copyright (c) 2001-2003
 *	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
 *	All rights reserved.
 *
 * Author: Harti Brandt <[email protected]>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON 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 ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Begemot: bsnmp/snmp_mibII/mibII_nettomedia.c,v 1.8 2004/08/06 08:47:03 brandt Exp $
 *
 * Read-only implementation of the Arp table (ipNetToMediaTable)
 *
 * The problem with the table is, that we don't receive routing message
 * when a) an arp table entry is resolved and b) when an arp table entry is
 * deleted automatically. Therefor we need to poll the table from time to
 * time.
 */
#include "mibII.h"
#include "mibII_oid.h"

#define ARPREFRESH	30

struct mibarp *
mib_find_arp(const struct mibif *ifp, struct in_addr in)
{
	struct mibarp *at;
	uint32_t a = ntohl(in.s_addr);

	if (get_ticks() >= mibarpticks + ARPREFRESH)
		mib_arp_update();

	TAILQ_FOREACH(at, &mibarp_list, link)
		if (at->index.subs[0] == ifp->index &&
		    (at->index.subs[1] == ((a >> 24) & 0xff)) &&
		    (at->index.subs[2] == ((a >> 16) & 0xff)) &&
		    (at->index.subs[3] == ((a >>  8) & 0xff)) &&
		    (at->index.subs[4] == ((a >>  0) & 0xff)))
			return (at);
	return (NULL);
}

struct mibarp *
mib_arp_create(const struct mibif *ifp, struct in_addr in, const u_char *phys,
    size_t physlen)
{
	struct mibarp *at;
	uint32_t a = ntohl(in.s_addr);

	if ((at = malloc(sizeof(*at))) == NULL)
		return (NULL);
	at->flags = 0;

	at->index.len = 5;
	at->index.subs[0] = ifp->index;
	at->index.subs[1] = (a >> 24) & 0xff;
	at->index.subs[2] = (a >> 16) & 0xff;
	at->index.subs[3] = (a >>  8) & 0xff;
	at->index.subs[4] = (a >>  0) & 0xff;
	if ((at->physlen = physlen) > sizeof(at->phys))
		at->physlen = sizeof(at->phys);
	memcpy(at->phys, phys, at->physlen);

	INSERT_OBJECT_OID(at, &mibarp_list);

	return (at);
}

void
mib_arp_delete(struct mibarp *at)
{
	TAILQ_REMOVE(&mibarp_list, at, link);
	free(at);
}

int
op_nettomedia(struct snmp_context *ctx __unused, struct snmp_value *value,
    u_int sub, u_int iidx __unused, enum snmp_op op)
{
	struct mibarp *at;

	at = NULL;	/* gcc */

	if (get_ticks() >= mibarpticks + ARPREFRESH)
		mib_arp_update();

	switch (op) {

	  case SNMP_OP_GETNEXT:
		if ((at = NEXT_OBJECT_OID(&mibarp_list, &value->var, sub)) == NULL)
			return (SNMP_ERR_NOSUCHNAME);
		index_append(&value->var, sub, &at->index);
		break;

	  case SNMP_OP_GET:
		if ((at = FIND_OBJECT_OID(&mibarp_list, &value->var, sub)) == NULL)
			return (SNMP_ERR_NOSUCHNAME);
		break;

	  case SNMP_OP_SET:
		if ((at = FIND_OBJECT_OID(&mibarp_list, &value->var, sub)) == NULL)
			return (SNMP_ERR_NO_CREATION);
		return (SNMP_ERR_NOT_WRITEABLE);

	  case SNMP_OP_ROLLBACK:
	  case SNMP_OP_COMMIT:
		abort();
	}

	switch (value->var.subs[sub - 1]) {

	  case LEAF_ipNetToMediaIfIndex:
		value->v.integer = at->index.subs[0];
		break;

	  case LEAF_ipNetToMediaPhysAddress:
		return (string_get(value, at->phys, at->physlen));

	  case LEAF_ipNetToMediaNetAddress:
		value->v.ipaddress[0] = at->index.subs[1];
		value->v.ipaddress[1] = at->index.subs[2];
		value->v.ipaddress[2] = at->index.subs[3];
		value->v.ipaddress[3] = at->index.subs[4];
		break;

	  case LEAF_ipNetToMediaType:
		value->v.integer = (at->flags & MIBARP_PERM) ? 4 : 3;
		break;
	}
	return (SNMP_ERR_NOERROR);
}