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/* MTU get using kvm_read.
* Copyright (C) 1999 Kunihiro Ishiguro
*
* This file is part of GNU Zebra.
*
* GNU Zebra is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* GNU Zebra is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Zebra; see the file COPYING. If not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <zebra.h>
#include <kvm.h>
#include <limits.h>
#include <fcntl.h>
#include "if.h"
/* get interface MTU to use kvm_read */
void
if_kvm_get_mtu (struct interface *ifp)
{
kvm_t *kvmd;
struct ifnet ifnet;
unsigned long ifnetaddr;
int len;
char ifname[IFNAMSIZ];
char tname[INTERFACE_NAMSIZ + 1];
char buf[_POSIX2_LINE_MAX];
struct nlist nl[] =
{
{"_ifnet"},
{""}
};
ifp->mtu6 = ifp->mtu = -1;
kvmd = kvm_openfiles (NULL, NULL, NULL, O_RDONLY, buf);
if (kvmd == NULL)
return ;
kvm_nlist(kvmd, nl);
ifnetaddr = nl[0].n_value;
if (kvm_read(kvmd, ifnetaddr, (char *)&ifnetaddr, sizeof ifnetaddr) < 0)
{
kvm_close (kvmd);
return ;
}
while(ifnetaddr != 0)
{
if (kvm_read (kvmd, ifnetaddr, (char *)&ifnet, sizeof ifnet) < 0)
{
kvm_close (kvmd);
return ;
}
if (kvm_read (kvmd, (u_long)ifnet.if_name, ifname, IFNAMSIZ) < 0)
{
kvm_close (kvmd);
return ;
}
len = snprintf (tname, INTERFACE_NAMSIZ + 1,
"%s%d", ifname, ifnet.if_unit);
if (strncmp (tname, ifp->name, len) == 0)
break;
ifnetaddr = (u_long)ifnet.if_next;
}
kvm_close (kvmd);
if (ifnetaddr == 0)
{
return ;
}
ifp->mtu6 = ifp->mtu = ifnet.if_mtu;
}
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