NetworkInador/lib/veth.c

/*
 * veth.c
 * This file is part of Network-inador
 *
 * Copyright (C) 2023 - Félix Arreola Rodríguez
 *
 * Network-inador 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 of the License, or
 * (at your option) any later version.
 *
 * Network-inador 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 Network-inador; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, 
 * Boston, MA  02110-1301  USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>

#include <netlink/socket.h>
#include <netlink/msg.h>

#include <net/ethernet.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <linux/veth.h>

#include "network-inador-private.h"
#include "interfaces.h"

int interfaces_veth_create (NetworkInadorHandle *handle, const char *link_name, const char *peer_name) {
	struct nl_msg * msg;
	struct ifinfomsg iface_hdr, peer_hdr;
	struct nlattr *info, *data, *peer;
	int ret, error, len;
	const char *type = "veth";
	
	if (link_name != NULL) {
		/* Validar la longitud del nombre, por seguridad */
		len = strlen (link_name) + 1;
		if (len == 1) {
			/* Nombre muy corto */
			return -1;
		}
		if (len > IFNAMSIZ) {
			/* Nombre muy largo */
			return -1;
		}
	}
	
	if (peer_name != NULL) {
		/* Validar la longitud del nombre, por seguridad */
		len = strlen (peer_name) + 1;
		if (len == 1) {
			/* Nombre muy corto */
			return -1;
		}
		if (len > IFNAMSIZ) {
			/* Nombre muy largo */
			return -1;
		}
	}
	
	memset (&iface_hdr, 0, sizeof (iface_hdr));
	iface_hdr.ifi_family = AF_UNSPEC;
	iface_hdr.ifi_index = 0;
	
	msg = nlmsg_alloc_simple (RTM_NEWLINK, NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL);
	ret = nlmsg_append (msg, &iface_hdr, sizeof (iface_hdr), NLMSG_ALIGNTO);
	
	if (ret != 0) {
		nlmsg_free (msg);
		
		return -1;
	}
	
	/* Anexar el nombre, si es que especificaron uno */
	if (link_name != NULL) {
		ret = nla_put (msg, IFLA_IFNAME, strlen (link_name) + 1, link_name);
		
		if (ret != 0) {
			nlmsg_free (msg);
			
			return -1;
		}
	}
	
	info = nla_nest_start (msg, IFLA_LINKINFO);
	
	if (info == NULL) {
		nlmsg_free (msg);
		
		return -1;
	}
	
	//ret = nla_put_string (msg, IFLA_INFO_KIND, type);
	ret = nla_put (msg, IFLA_INFO_KIND, strlen (type), type);
	
	if (ret != 0) {
		nla_nest_end (msg, info);
		nlmsg_free (msg);
		
		return -1;
	}
	
	/* Ver cómo anexar IFLA_INFO_DATA */
	data = nla_nest_start (msg, IFLA_INFO_DATA);
	
	/* Vaciar la estructura del peer */
	memset (&peer_hdr, 0, sizeof (peer_hdr));
	peer_hdr.ifi_family = AF_UNSPEC;
	peer_hdr.ifi_index = 0;
	
	peer = nla_nest_start (msg, VETH_INFO_PEER);
	nlmsg_append (msg, &peer_hdr, sizeof (peer_hdr), 0);
	
	if (peer_name != NULL) {
		ret = nla_put (msg, IFLA_IFNAME, strlen (peer_name) + 1, peer_name);
		
		if (ret != 0) {
			nlmsg_free (msg);
			
			return -1;
		}
	}
	
	nla_nest_end (msg, peer); /* Cerrar el VETH_INFO_PEER */
	
	nla_nest_end (msg, data); /* Cerrar el IFLA_INFO_DATA */
	
	nla_nest_end (msg, info); /* Cerrar el IFLA_LINKINFO */
	
	nl_complete_msg (handle->nl_sock_route, msg);
	
	ret = nl_send (handle->nl_sock_route, msg);
	
	nlmsg_free (msg);
	if (ret <= 0) {
		return -1;
	}
	
	error = 0;
	nl_socket_modify_cb (handle->nl_sock_route, NL_CB_VALID, NL_CB_CUSTOM, _interfaces_wait_ack_or_error, &error);
	nl_socket_modify_cb (handle->nl_sock_route, NL_CB_INVALID, NL_CB_CUSTOM, _interfaces_wait_ack_or_error, &error);
	nl_socket_modify_cb (handle->nl_sock_route, NL_CB_ACK, NL_CB_CUSTOM, _interfaces_wait_ack_or_error, &error);
	nl_socket_modify_err_cb (handle->nl_sock_route, NL_CB_CUSTOM, _interfaces_wait_error, &error);
	
	nl_recvmsgs_default (handle->nl_sock_route);
	
	if (ret <= 0 || error < 0) {
		return -1;
	}
	
	return 0;
}