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/*
* iface.c - Network interface control functions
*
* Copyright (C) 2006, 2007, 2008 Red Hat, Inc. All rights reserved.
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
* Author(s): David Cantrell <dcantrell@redhat.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netlink/netlink.h>
#include <netlink/socket.h>
#include <netlink/route/addr.h>
#include <netlink/route/link.h>
#include "iface.h"
#include "str.h"
/*
* Return an NETLINK_ROUTE cache.
*/
struct nl_cache *iface_get_link_cache(struct nl_handle **handle) {
struct nl_cache *cache = NULL;
if ((*handle = nl_handle_alloc()) == NULL) {
perror("nl_handle_alloc() failure in iface_get_link_cache()");
return NULL;
}
if (nl_connect(*handle, NETLINK_ROUTE)) {
perror("nl_connect() failure in iface_get_link_cache()");
nl_handle_destroy(*handle);
return NULL;
}
if ((cache = rtnl_link_alloc_cache(*handle)) == NULL) {
perror("rtnl_link_alloc_cache() failure in iface_get_link_cache()");
nl_close(*handle);
nl_handle_destroy(*handle);
return NULL;
}
return cache;
}
/*
* Given an interface name (e.g., eth0), return the IP address in human
* readable format (i.e., the output from inet_ntop()). Return NULL for
* no match. NOTE: This function will check for IPv6 and IPv4
* addresses. In the case where the interface has both, the IPv4 address
* is returned. The only way you will get an IPv6 address from this function
* is if that's the only address configured for the interface.
*/
char *iface_ip2str(char *ifname) {
int ifindex = -1, buflen = 0, family = 0;
char *buf = NULL, *bufv4 = NULL, *bufv6 = NULL, *pos = NULL;
struct nl_handle *handle = NULL;
struct nl_cache *cache = NULL;
struct nl_object *obj = NULL;
struct rtnl_addr *raddr = NULL;
struct nl_addr *addr = NULL;
if (ifname == NULL) {
perror("Missing ifname in iface_ip2str()");
return NULL;
}
if ((cache = iface_get_link_cache(&handle)) == NULL) {
perror("iface_get_link_cache() failure in iface_ip2str()");
return NULL;
}
ifindex = rtnl_link_name2i(cache, ifname);
if ((cache = rtnl_addr_alloc_cache(handle)) == NULL) {
perror("rtnl_addr_alloc_cache() failure in iface_ip2str()");
goto ip2str_error;
}
/* find the IPv4 and IPv6 addresses for this interface */
if ((obj = nl_cache_get_first(cache)) == NULL) {
perror("nl_cache_get_first() failure in iface_ip2str()");
goto ip2str_error;
}
do {
raddr = (struct rtnl_addr *) obj;
if (rtnl_addr_get_ifindex(raddr) == ifindex) {
family = rtnl_addr_get_family(raddr);
if (family == AF_INET || family == AF_INET6) {
/* skip if we have already saved an address */
/* FIXME: we should handle multiple addresses for the same
* family per interface
*/
if (family == AF_INET && bufv4 != NULL) {
continue;
}
if (family == AF_INET6 && bufv6 != NULL) {
continue;
}
/* get the address */
addr = rtnl_addr_get_local(raddr);
/* convert to human readable format */
if (family == AF_INET) {
buflen = INET_ADDRSTRLEN;
} else if (family == AF_INET6) {
buflen = INET6_ADDRSTRLEN;
}
buflen += 1;
if ((buf = malloc(buflen)) == NULL) {
perror("malloc() failure on buf in iface_ip2str()");
nl_addr_destroy(addr);
goto ip2str_error;
}
buf = nl_addr2str(addr, buf, buflen);
nl_addr_destroy(addr);
/* trim the prefix notation */
if ((pos = index(buf, '/')) != NULL) {
*pos = '\0';
if ((buf = realloc(buf, strlen(buf) + 1)) == NULL) {
perror("realloc() failure on buf in iface_ip2str()");
nl_addr_destroy(addr);
goto ip2str_error;
}
}
/* save the IP address in the right buffer */
if (family == AF_INET) {
bufv4 = strdup(buf);
} else if (family == AF_INET6) {
bufv6 = strdup(buf);
}
/* empty the main conversion buffer */
if (buf) {
free(buf);
buf = NULL;
}
}
}
} while ((obj = nl_cache_get_next(obj)) != NULL);
ip2str_error:
nl_close(handle);
nl_handle_destroy(handle);
/* return IPv4 address if we have both families
* return IPv6 address if we only have IPv6 family
* return NULL otherwise
*/
if ((bufv4 && bufv6) || (bufv4 && !bufv6)) {
return bufv4;
} else if (!bufv4 && bufv6) {
return bufv6;
} else {
return NULL;
}
}
/**
* Given an interface name (e.g., eth0), return the MAC address in human
* readable format (e.g., 00:11:52:12:D9:A0). Return NULL for no match.
*/
char *iface_mac2str(char *ifname) {
int buflen = 20;
char *buf = NULL;
struct nl_handle *handle = NULL;
struct nl_cache *cache = NULL;
struct rtnl_link *link = NULL;
struct nl_addr *addr = NULL;
if (ifname == NULL) {
perror("Missing ifname in iface_mac2str()");
return NULL;
}
if ((cache = iface_get_link_cache(&handle)) == NULL) {
perror("iface_get_link_cache() failure in iface_mac2str()");
return NULL;
}
if ((link = rtnl_link_get_by_name(cache, ifname)) == NULL) {
perror("rtnl_link_get_by_name() failure in iface_mac2str()");
goto mac2str_error2;
}
if ((addr = rtnl_link_get_addr(link)) == NULL) {
perror("rtnl_link_get_addr() failure in iface_mac2str()");
goto mac2str_error3;
}
if ((buf = malloc(buflen)) == NULL) {
perror("malloc() failure on buf in iface_mac2str()");
goto mac2str_error4;
}
if ((buf = nl_addr2str(addr, buf, buflen)) != NULL) {
buf = str2upper(buf);
}
mac2str_error4:
nl_addr_destroy(addr);
mac2str_error3:
rtnl_link_put(link);
mac2str_error2:
nl_close(handle);
nl_handle_destroy(handle);
return buf;
}
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