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/* SPDX-License-Identifier: LGPL-2.1-only */
#include "nl-default.h"
#include <net/if.h>
#include <netlink/route/link.h>
int main(void)
{
struct nl_sock *sk;
struct rtnl_link *link, *change;
struct nl_cache *cache;
int err = 0;
sk = nl_socket_alloc();
if ((err = nl_connect(sk, NETLINK_ROUTE)) < 0) {
nl_perror(err, "Unable to connect socket");
return err;
}
if ((err = rtnl_link_alloc_cache(sk, AF_UNSPEC, &cache)) < 0) {
nl_perror(err, "Unable to allocate cache");
goto out;
}
if (!(link = rtnl_link_get_by_name(cache, "lo"))) {
fprintf(stderr, "Interface not found\n");
err = 1;
goto out;
}
/* exit if the loopback interface is already deactivated */
err = rtnl_link_get_flags(link);
if (!(err & IFF_UP)) {
err = 0;
goto out;
}
change = rtnl_link_alloc();
rtnl_link_unset_flags(change, IFF_UP);
if ((err = rtnl_link_change(sk, link, change, 0)) < 0) {
nl_perror(err, "Unable to deactivate lo");
goto out;
}
rtnl_link_set_flags(change, IFF_UP);
if ((err = rtnl_link_change(sk, link, change, 0)) < 0) {
nl_perror(err, "Unable to activate lo");
goto out;
}
err = 0;
out:
nl_socket_free(sk);
return err;
}
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