libvirt/src/util/virnetdevip.c

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/*
* Copyright (C) 2007-2016 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "virnetdevip.h"
#include "virnetdev.h"
#include "virnetlink.h"
#include "virfile.h"
#include "virerror.h"
#include "virlog.h"
#include "virstring.h"
#include "vircommand.h"
#include "viralloc.h"
#if WITH_GETIFADDRS
# include <ifaddrs.h>
#endif
#ifndef WIN32
# include <sys/ioctl.h>
#endif
#ifdef WITH_NET_IF_H
# include <net/if.h>
#endif
#include <fcntl.h>
#ifdef __linux__
# include <linux/sockios.h>
# include <linux/if_vlan.h>
network: Only check kernel added routes in virNetDevIPCheckIPv6Forwarding The original motivation for adding virNetDevIPCheckIPv6Forwarding (commit 00d28a78b5) was that networking routes would disappear when ipv6 forwarding was enabled for an interface. This is a fairly undocumented side-effect of the "accept_ra" sysctl for an interface. 1 means the interface will accept_ra's if not forwarding, 2 means always accept_RAs; but it is not explained that enabling forwarding when accept_ra==1 will also clear any kernel RA assigned routes, very likely breaking your networking. The check to warn about this currently uses netlink to go through all the routes and then look at the accept_ra status of the interfaces. However, it has been noticed that this problem does not affect systems where IPv6 RA configuration is handled in userspace, e.g. via tools such as NetworkManager. In this case, the error message from libvirt is spurious, and modifying the forwarding state will not affect the RA state or disable your networking. If you refer to the function rt6_purge_dflt_routers() in the kernel, we can see that the routes being purged are only those with the kernel's RTF_ADDRCONF flag set; that is, routes added by the kernel's RA handling. Why does it do this? I think this is a Linux implementation decision; it has always been like that and there are some comments suggesting that it is because a router should be statically configured, rather than accepting external configurations. The solution implemented here is to convert the existing check into a walk of /proc/net/ipv6_route (because RTF_ADDRCONF is apparently not exposed in netlink) and look for routes with this flag set. We then check the accept_ra status for the interface, and if enabling forwarding would break things raise an error. This should hopefully avoid "interactive" users, who are likely to be using NetworkManager and the like, having false warnings when enabling IPv6, but retain the error check for users relying on kernel-based IPv6 interface auto-configuration. Signed-off-by: Ian Wienand <iwienand@redhat.com> Reviewed-by: Laine Stump <laine@redhat.com> Reviewed-by: Cedric Bosdonnat <CBosdonnat@suse.com>
2020-09-11 11:34:17 +00:00
# include <linux/ipv6_route.h>
#endif
network: Only check kernel added routes in virNetDevIPCheckIPv6Forwarding The original motivation for adding virNetDevIPCheckIPv6Forwarding (commit 00d28a78b5) was that networking routes would disappear when ipv6 forwarding was enabled for an interface. This is a fairly undocumented side-effect of the "accept_ra" sysctl for an interface. 1 means the interface will accept_ra's if not forwarding, 2 means always accept_RAs; but it is not explained that enabling forwarding when accept_ra==1 will also clear any kernel RA assigned routes, very likely breaking your networking. The check to warn about this currently uses netlink to go through all the routes and then look at the accept_ra status of the interfaces. However, it has been noticed that this problem does not affect systems where IPv6 RA configuration is handled in userspace, e.g. via tools such as NetworkManager. In this case, the error message from libvirt is spurious, and modifying the forwarding state will not affect the RA state or disable your networking. If you refer to the function rt6_purge_dflt_routers() in the kernel, we can see that the routes being purged are only those with the kernel's RTF_ADDRCONF flag set; that is, routes added by the kernel's RA handling. Why does it do this? I think this is a Linux implementation decision; it has always been like that and there are some comments suggesting that it is because a router should be statically configured, rather than accepting external configurations. The solution implemented here is to convert the existing check into a walk of /proc/net/ipv6_route (because RTF_ADDRCONF is apparently not exposed in netlink) and look for routes with this flag set. We then check the accept_ra status for the interface, and if enabling forwarding would break things raise an error. This should hopefully avoid "interactive" users, who are likely to be using NetworkManager and the like, having false warnings when enabling IPv6, but retain the error check for users relying on kernel-based IPv6 interface auto-configuration. Signed-off-by: Ian Wienand <iwienand@redhat.com> Reviewed-by: Laine Stump <laine@redhat.com> Reviewed-by: Cedric Bosdonnat <CBosdonnat@suse.com>
2020-09-11 11:34:17 +00:00
#define PROC_NET_IPV6_ROUTE "/proc/net/ipv6_route"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.netdevip");
#if defined(WITH_LIBNL)
static int
virNetDevGetIPAddressBinary(virSocketAddr *addr, void **data, size_t *len)
{
if (!addr)
return -1;
switch (VIR_SOCKET_ADDR_FAMILY(addr)) {
case AF_INET:
*data = &addr->data.inet4.sin_addr;
*len = sizeof(struct in_addr);
break;
case AF_INET6:
*data = &addr->data.inet6.sin6_addr;
*len = sizeof(struct in6_addr);
break;
default:
return -1;
}
return 0;
}
static struct nl_msg *
virNetDevCreateNetlinkAddressMessage(int messageType,
const char *ifname,
virSocketAddr *addr,
unsigned int prefix,
virSocketAddr *broadcast,
virSocketAddr *peer)
{
struct nl_msg *nlmsg = NULL;
struct ifaddrmsg ifa;
unsigned int ifindex;
void *addrData = NULL;
void *peerData = NULL;
void *broadcastData = NULL;
size_t addrDataLen;
if (virNetDevGetIPAddressBinary(addr, &addrData, &addrDataLen) < 0)
return NULL;
if (peer && VIR_SOCKET_ADDR_VALID(peer)) {
if (virNetDevGetIPAddressBinary(peer, &peerData, &addrDataLen) < 0)
return NULL;
} else if (broadcast) {
if (virNetDevGetIPAddressBinary(broadcast, &broadcastData,
&addrDataLen) < 0)
return NULL;
}
/* Get the interface index */
if ((ifindex = if_nametoindex(ifname)) == 0)
return NULL;
if (!(nlmsg = nlmsg_alloc_simple(messageType,
NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL))) {
virReportOOMError();
return NULL;
}
memset(&ifa, 0, sizeof(ifa));
ifa.ifa_prefixlen = prefix;
ifa.ifa_family = VIR_SOCKET_ADDR_FAMILY(addr);
ifa.ifa_index = ifindex;
ifa.ifa_scope = 0;
if (nlmsg_append(nlmsg, &ifa, sizeof(ifa), NLMSG_ALIGNTO) < 0)
goto buffer_too_small;
if (nla_put(nlmsg, IFA_LOCAL, addrDataLen, addrData) < 0)
goto buffer_too_small;
if (peerData) {
if (nla_put(nlmsg, IFA_ADDRESS, addrDataLen, peerData) < 0)
goto buffer_too_small;
}
if (broadcastData) {
if (nla_put(nlmsg, IFA_BROADCAST, addrDataLen, broadcastData) < 0)
goto buffer_too_small;
}
return nlmsg;
buffer_too_small:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("allocated netlink buffer is too small"));
nlmsg_free(nlmsg);
return NULL;
}
/**
* virNetDevIPAddrAdd:
* @ifname: the interface name
* @addr: the IP address (IPv4 or IPv6)
* @peer: The IP address of peer (IPv4 or IPv6)
* @prefix: number of 1 bits in the netmask
*
* Add an IP address to an interface. This function *does not* remove
* any previously added IP addresses - that must be done separately with
* virNetDevIPAddrClear.
*
* Returns 0 in case of success or -1 in case of error.
*/
int
virNetDevIPAddrAdd(const char *ifname,
virSocketAddr *addr,
virSocketAddr *peer,
unsigned int prefix)
{
unsigned int recvbuflen;
g_autoptr(virNetlinkMsg) nlmsg = NULL;
g_autoptr(virSocketAddr) broadcast = NULL;
g_autofree struct nlmsghdr *resp = NULL;
g_autofree char *ipStr = NULL;
g_autofree char *peerStr = NULL;
g_autofree char *bcastStr = NULL;
ipStr = virSocketAddrFormat(addr);
if (peer && VIR_SOCKET_ADDR_VALID(peer))
peerStr = virSocketAddrFormat(peer);
/* The caller needs to provide a correct address */
if (VIR_SOCKET_ADDR_FAMILY(addr) == AF_INET &&
!(peer && VIR_SOCKET_ADDR_VALID(peer))) {
/* compute a broadcast address if this is IPv4 */
broadcast = g_new0(virSocketAddr, 1);
if (virSocketAddrBroadcastByPrefix(addr, prefix, broadcast) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to determine broadcast address for '%s/%d'"),
ipStr, prefix);
return -1;
}
bcastStr = virSocketAddrFormat(broadcast);
}
VIR_DEBUG("Adding IP address %s/%d%s%s%s%s to %s",
NULLSTR(ipStr), prefix,
peerStr ? " peer " : "", peerStr ? peerStr : "",
bcastStr ? " bcast " : "", bcastStr ? bcastStr : "",
ifname);
if (!(nlmsg = virNetDevCreateNetlinkAddressMessage(RTM_NEWADDR, ifname,
addr, prefix,
broadcast, peer)))
return -1;
if (virNetlinkCommand(nlmsg, &resp, &recvbuflen,
0, 0, NETLINK_ROUTE, 0) < 0)
return -1;
if (virNetlinkGetErrorCode(resp, recvbuflen) < 0) {
virReportError(VIR_ERR_SYSTEM_ERROR,
_("Failed to add IP address %s/%d%s%s%s%s to %s"),
ipStr, prefix,
peerStr ? " peer " : "", peerStr ? peerStr : "",
bcastStr ? " bcast " : "", bcastStr ? bcastStr : "",
ifname);
return -1;
}
return 0;
}
/**
* virNetDevIPAddrDel:
* @ifname: the interface name
* @addr: the IP address (IPv4 or IPv6)
* @prefix: number of 1 bits in the netmask
*
* Delete an IP address from an interface.
*
* Returns 0 in case of success or -1 in case of error.
*/
int
virNetDevIPAddrDel(const char *ifname,
virSocketAddr *addr,
unsigned int prefix)
{
unsigned int recvbuflen;
g_autoptr(virNetlinkMsg) nlmsg = NULL;
g_autofree struct nlmsghdr *resp = NULL;
if (!(nlmsg = virNetDevCreateNetlinkAddressMessage(RTM_DELADDR, ifname,
addr, prefix,
NULL, NULL)))
return -1;
if (virNetlinkCommand(nlmsg, &resp, &recvbuflen, 0, 0,
NETLINK_ROUTE, 0) < 0)
return -1;
if (virNetlinkGetErrorCode(resp, recvbuflen) < 0) {
virReportError(VIR_ERR_SYSTEM_ERROR,
_("Error removing IP address from %s"), ifname);
return -1;
}
return 0;
}
/**
* virNetDevIPRouteAdd:
* @ifname: the interface name
* @addr: the IP network address (IPv4 or IPv6)
* @prefix: number of 1 bits in the netmask
* @gateway: via address for route (same as @addr)
*
* Add a route for a network IP address to an interface. This function
* *does not* remove any previously added IP static routes.
*
* Returns 0 in case of success or -1 in case of error.
*/
int
virNetDevIPRouteAdd(const char *ifname,
virSocketAddrPtr addr,
unsigned int prefix,
virSocketAddrPtr gateway,
unsigned int metric)
{
unsigned int recvbuflen;
unsigned int ifindex;
struct rtmsg rtmsg;
void *gatewayData = NULL;
void *addrData = NULL;
size_t addrDataLen;
int errCode;
virSocketAddr defaultAddr;
virSocketAddrPtr actualAddr;
g_autoptr(virNetlinkMsg) nlmsg = NULL;
g_autofree char *toStr = NULL;
g_autofree char *viaStr = NULL;
g_autofree struct nlmsghdr *resp = NULL;
actualAddr = addr;
/* If we have no valid network address, then use the default one */
if (!addr || !VIR_SOCKET_ADDR_VALID(addr)) {
int family = VIR_SOCKET_ADDR_FAMILY(gateway);
VIR_DEBUG("computing default address");
if (family == AF_INET) {
if (virSocketAddrParseIPv4(&defaultAddr, VIR_SOCKET_ADDR_IPV4_ALL) < 0)
return -1;
} else {
if (virSocketAddrParseIPv6(&defaultAddr, VIR_SOCKET_ADDR_IPV6_ALL) < 0)
return -1;
}
actualAddr = &defaultAddr;
}
toStr = virSocketAddrFormat(actualAddr);
viaStr = virSocketAddrFormat(gateway);
VIR_DEBUG("Adding route %s/%d via %s", toStr, prefix, viaStr);
if (virNetDevGetIPAddressBinary(actualAddr, &addrData, &addrDataLen) < 0 ||
virNetDevGetIPAddressBinary(gateway, &gatewayData, &addrDataLen) < 0)
return -1;
/* Get the interface index */
if ((ifindex = if_nametoindex(ifname)) == 0)
return -1;
if (!(nlmsg = nlmsg_alloc_simple(RTM_NEWROUTE,
NLM_F_REQUEST | NLM_F_CREATE |
NLM_F_EXCL))) {
virReportOOMError();
return -1;
}
memset(&rtmsg, 0, sizeof(rtmsg));
rtmsg.rtm_family = VIR_SOCKET_ADDR_FAMILY(gateway);
rtmsg.rtm_table = RT_TABLE_MAIN;
rtmsg.rtm_scope = RT_SCOPE_UNIVERSE;
rtmsg.rtm_protocol = RTPROT_BOOT;
rtmsg.rtm_type = RTN_UNICAST;
rtmsg.rtm_dst_len = prefix;
if (nlmsg_append(nlmsg, &rtmsg, sizeof(rtmsg), NLMSG_ALIGNTO) < 0)
goto buffer_too_small;
if (prefix > 0 && nla_put(nlmsg, RTA_DST, addrDataLen, addrData) < 0)
goto buffer_too_small;
if (nla_put(nlmsg, RTA_GATEWAY, addrDataLen, gatewayData) < 0)
goto buffer_too_small;
if (nla_put_u32(nlmsg, RTA_OIF, ifindex) < 0)
goto buffer_too_small;
if (metric > 0 && nla_put_u32(nlmsg, RTA_PRIORITY, metric) < 0)
goto buffer_too_small;
if (virNetlinkCommand(nlmsg, &resp, &recvbuflen, 0, 0,
NETLINK_ROUTE, 0) < 0)
return -1;
if ((errCode = virNetlinkGetErrorCode(resp, recvbuflen)) < 0) {
virReportSystemError(errCode, _("Error adding route to %s"), ifname);
return -1;
}
return 0;
buffer_too_small:
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("allocated netlink buffer is too small"));
return -1;
}
#else /* defined(WITH_LIBNL) */
int
virNetDevIPAddrAdd(const char *ifname,
virSocketAddr *addr,
virSocketAddr *peer,
unsigned int prefix)
{
virSocketAddr broadcast;
g_autoptr(virCommand) cmd = NULL;
g_autofree char *addrstr = NULL;
g_autofree char *bcaststr = NULL;
g_autofree char *peerstr = NULL;
if (!(addrstr = virSocketAddrFormat(addr)))
return -1;
if (peer && VIR_SOCKET_ADDR_VALID(peer) && !(peerstr = virSocketAddrFormat(peer)))
return -1;
/* format up a broadcast address if this is IPv4 */
if (!peerstr &&
((VIR_SOCKET_ADDR_IS_FAMILY(addr, AF_INET)) &&
((virSocketAddrBroadcastByPrefix(addr, prefix, &broadcast) < 0) ||
!(bcaststr = virSocketAddrFormat(&broadcast))))) {
return -1;
}
# ifdef IFCONFIG_PATH
cmd = virCommandNew(IFCONFIG_PATH);
virCommandAddArg(cmd, ifname);
if (VIR_SOCKET_ADDR_IS_FAMILY(addr, AF_INET6))
virCommandAddArg(cmd, "inet6");
else
virCommandAddArg(cmd, "inet");
virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
if (peerstr)
virCommandAddArgList(cmd, "pointopoint", peerstr, NULL);
if (bcaststr)
virCommandAddArgList(cmd, "broadcast", bcaststr, NULL);
virCommandAddArg(cmd, "alias");
# else
cmd = virCommandNew(IP_PATH);
virCommandAddArgList(cmd, "addr", "add", NULL);
virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
if (peerstr)
virCommandAddArgList(cmd, "peer", peerstr, NULL);
if (bcaststr)
virCommandAddArgList(cmd, "broadcast", bcaststr, NULL);
virCommandAddArgList(cmd, "dev", ifname, NULL);
# endif
if (virCommandRun(cmd, NULL) < 0)
return -1;
return 0;
}
int
virNetDevIPAddrDel(const char *ifname,
virSocketAddr *addr,
unsigned int prefix)
{
g_autoptr(virCommand) cmd = NULL;
g_autofree char *addrstr = NULL;
if (!(addrstr = virSocketAddrFormat(addr)))
return -1;
# ifdef IFCONFIG_PATH
cmd = virCommandNew(IFCONFIG_PATH);
virCommandAddArg(cmd, ifname);
if (VIR_SOCKET_ADDR_IS_FAMILY(addr, AF_INET6))
virCommandAddArg(cmd, "inet6");
else
virCommandAddArg(cmd, "inet");
virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
virCommandAddArg(cmd, "-alias");
# else
cmd = virCommandNew(IP_PATH);
virCommandAddArgList(cmd, "addr", "del", NULL);
virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
virCommandAddArgList(cmd, "dev", ifname, NULL);
# endif
if (virCommandRun(cmd, NULL) < 0)
return -1;
return 0;
}
int
virNetDevIPRouteAdd(const char *ifname,
virSocketAddrPtr addr,
unsigned int prefix,
virSocketAddrPtr gateway,
unsigned int metric)
{
g_autoptr(virCommand) cmd = NULL;
g_autofree char *addrstr = NULL;
g_autofree char *gatewaystr = NULL;
if (!(addrstr = virSocketAddrFormat(addr)))
return -1;
if (!(gatewaystr = virSocketAddrFormat(gateway)))
return -1;
cmd = virCommandNew(IP_PATH);
virCommandAddArgList(cmd, "route", "add", NULL);
virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
virCommandAddArgList(cmd, "via", gatewaystr, "dev", ifname,
"proto", "static", "metric", NULL);
virCommandAddArgFormat(cmd, "%u", metric);
if (virCommandRun(cmd, NULL) < 0)
return -1;
return 0;
}
#endif /* defined(HAVE_LIBNL) */
network: Only check kernel added routes in virNetDevIPCheckIPv6Forwarding The original motivation for adding virNetDevIPCheckIPv6Forwarding (commit 00d28a78b5) was that networking routes would disappear when ipv6 forwarding was enabled for an interface. This is a fairly undocumented side-effect of the "accept_ra" sysctl for an interface. 1 means the interface will accept_ra's if not forwarding, 2 means always accept_RAs; but it is not explained that enabling forwarding when accept_ra==1 will also clear any kernel RA assigned routes, very likely breaking your networking. The check to warn about this currently uses netlink to go through all the routes and then look at the accept_ra status of the interfaces. However, it has been noticed that this problem does not affect systems where IPv6 RA configuration is handled in userspace, e.g. via tools such as NetworkManager. In this case, the error message from libvirt is spurious, and modifying the forwarding state will not affect the RA state or disable your networking. If you refer to the function rt6_purge_dflt_routers() in the kernel, we can see that the routes being purged are only those with the kernel's RTF_ADDRCONF flag set; that is, routes added by the kernel's RA handling. Why does it do this? I think this is a Linux implementation decision; it has always been like that and there are some comments suggesting that it is because a router should be statically configured, rather than accepting external configurations. The solution implemented here is to convert the existing check into a walk of /proc/net/ipv6_route (because RTF_ADDRCONF is apparently not exposed in netlink) and look for routes with this flag set. We then check the accept_ra status for the interface, and if enabling forwarding would break things raise an error. This should hopefully avoid "interactive" users, who are likely to be using NetworkManager and the like, having false warnings when enabling IPv6, but retain the error check for users relying on kernel-based IPv6 interface auto-configuration. Signed-off-by: Ian Wienand <iwienand@redhat.com> Reviewed-by: Laine Stump <laine@redhat.com> Reviewed-by: Cedric Bosdonnat <CBosdonnat@suse.com>
2020-09-11 11:34:17 +00:00
#if defined(__linux__)
static int
virNetDevIPGetAcceptRA(const char *ifname)
{
g_autofree char *path = NULL;
g_autofree char *buf = NULL;
char *suffix;
int accept_ra = -1;
path = g_strdup_printf("/proc/sys/net/ipv6/conf/%s/accept_ra",
ifname ? ifname : "all");
if ((virFileReadAll(path, 512, &buf) < 0) ||
(virStrToLong_i(buf, &suffix, 10, &accept_ra) < 0))
return -1;
return accept_ra;
}
/**
* virNetDevIPCheckIPv6Forwarding
*
* This function checks if IPv6 routes have the RTF_ADDRCONF flag set,
* indicating they have been created by the kernel's RA configuration
* handling. These routes are subject to being flushed when ipv6
* forwarding is enabled unless accept_ra is explicitly set to "2".
* This will most likely result in ipv6 networking being broken.
*
* Returns: true if it is safe to enable forwarding, or false if
* breakable routes are found.
*
**/
bool
virNetDevIPCheckIPv6Forwarding(void)
{
int len;
char *cur;
g_autofree char *buf = NULL;
/* lines are 150 chars */
enum {MAX_ROUTE_SIZE = 150*100000};
/* This is /proc/sys/net/ipv6/conf/all/accept_ra */
int all_accept_ra = virNetDevIPGetAcceptRA(NULL);
/* Read ipv6 routes */
if ((len = virFileReadAll(PROC_NET_IPV6_ROUTE,
MAX_ROUTE_SIZE, &buf)) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unable to read %s "
"for ipv6 forwarding checks"), PROC_NET_IPV6_ROUTE);
return false;
}
/* Dropping the last character to stop the loop */
if (len > 0)
buf[len-1] = '\0';
cur = buf;
while (cur) {
char route[33], flags[9], iface[9];
unsigned int flags_val;
char *iface_val;
int num;
char *nl = strchr(cur, '\n');
if (nl)
*nl++ = '\0';
num = sscanf(cur, "%32s %*s %*s %*s %*s %*s %*s %*s %8s %8s",
route, flags, iface);
cur = nl;
if (num != 3) {
VIR_DEBUG("Failed to parse route line: %s", cur);
continue;
}
if (virStrToLong_ui(flags, NULL, 16, &flags_val)) {
VIR_DEBUG("Failed to parse flags: %s", flags);
continue;
}
/* This is right justified, strip leading spaces */
iface_val = &iface[0];
while (*iface_val && g_ascii_isspace(*iface_val))
iface_val++;
VIR_DEBUG("%s iface %s flags %s : RTF_ADDRCONF %sset",
route, iface_val, flags,
(flags_val & RTF_ADDRCONF ? "" : "not "));
if (flags_val & RTF_ADDRCONF) {
int ret = virNetDevIPGetAcceptRA(iface_val);
VIR_DEBUG("%s reports accept_ra of %d",
iface_val, ret);
/* If the interface for this autoconfigured route
* has accept_ra == 1, or it is default and the "all"
* value of accept_ra == 1, it will be subject to
* flushing if forwarding is enabled.
*/
if (ret == 1 || (ret == 0 && all_accept_ra == 1)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Check the host setup: interface %s has kernel "
"autoconfigured IPv6 routes and enabling forwarding "
" without accept_ra set to 2 will cause the kernel "
"to flush them, breaking networking."), iface_val);
return false;
}
}
}
return true;
}
#else
bool
virNetDevIPCheckIPv6Forwarding(void)
{
network: Only check kernel added routes in virNetDevIPCheckIPv6Forwarding The original motivation for adding virNetDevIPCheckIPv6Forwarding (commit 00d28a78b5) was that networking routes would disappear when ipv6 forwarding was enabled for an interface. This is a fairly undocumented side-effect of the "accept_ra" sysctl for an interface. 1 means the interface will accept_ra's if not forwarding, 2 means always accept_RAs; but it is not explained that enabling forwarding when accept_ra==1 will also clear any kernel RA assigned routes, very likely breaking your networking. The check to warn about this currently uses netlink to go through all the routes and then look at the accept_ra status of the interfaces. However, it has been noticed that this problem does not affect systems where IPv6 RA configuration is handled in userspace, e.g. via tools such as NetworkManager. In this case, the error message from libvirt is spurious, and modifying the forwarding state will not affect the RA state or disable your networking. If you refer to the function rt6_purge_dflt_routers() in the kernel, we can see that the routes being purged are only those with the kernel's RTF_ADDRCONF flag set; that is, routes added by the kernel's RA handling. Why does it do this? I think this is a Linux implementation decision; it has always been like that and there are some comments suggesting that it is because a router should be statically configured, rather than accepting external configurations. The solution implemented here is to convert the existing check into a walk of /proc/net/ipv6_route (because RTF_ADDRCONF is apparently not exposed in netlink) and look for routes with this flag set. We then check the accept_ra status for the interface, and if enabling forwarding would break things raise an error. This should hopefully avoid "interactive" users, who are likely to be using NetworkManager and the like, having false warnings when enabling IPv6, but retain the error check for users relying on kernel-based IPv6 interface auto-configuration. Signed-off-by: Ian Wienand <iwienand@redhat.com> Reviewed-by: Laine Stump <laine@redhat.com> Reviewed-by: Cedric Bosdonnat <CBosdonnat@suse.com>
2020-09-11 11:34:17 +00:00
VIR_DEBUG("No checks for IPv6 forwarding issues on non-Linux systems");
return true;
}
network: Only check kernel added routes in virNetDevIPCheckIPv6Forwarding The original motivation for adding virNetDevIPCheckIPv6Forwarding (commit 00d28a78b5) was that networking routes would disappear when ipv6 forwarding was enabled for an interface. This is a fairly undocumented side-effect of the "accept_ra" sysctl for an interface. 1 means the interface will accept_ra's if not forwarding, 2 means always accept_RAs; but it is not explained that enabling forwarding when accept_ra==1 will also clear any kernel RA assigned routes, very likely breaking your networking. The check to warn about this currently uses netlink to go through all the routes and then look at the accept_ra status of the interfaces. However, it has been noticed that this problem does not affect systems where IPv6 RA configuration is handled in userspace, e.g. via tools such as NetworkManager. In this case, the error message from libvirt is spurious, and modifying the forwarding state will not affect the RA state or disable your networking. If you refer to the function rt6_purge_dflt_routers() in the kernel, we can see that the routes being purged are only those with the kernel's RTF_ADDRCONF flag set; that is, routes added by the kernel's RA handling. Why does it do this? I think this is a Linux implementation decision; it has always been like that and there are some comments suggesting that it is because a router should be statically configured, rather than accepting external configurations. The solution implemented here is to convert the existing check into a walk of /proc/net/ipv6_route (because RTF_ADDRCONF is apparently not exposed in netlink) and look for routes with this flag set. We then check the accept_ra status for the interface, and if enabling forwarding would break things raise an error. This should hopefully avoid "interactive" users, who are likely to be using NetworkManager and the like, having false warnings when enabling IPv6, but retain the error check for users relying on kernel-based IPv6 interface auto-configuration. Signed-off-by: Ian Wienand <iwienand@redhat.com> Reviewed-by: Laine Stump <laine@redhat.com> Reviewed-by: Cedric Bosdonnat <CBosdonnat@suse.com>
2020-09-11 11:34:17 +00:00
#endif /* defined(__linux__) */
/**
* virNetDevGetIPv4AddressIoctl:
* @ifname: name of the interface whose IP address we want
* @addr: filled with the IPv4 address
*
* This function gets the IPv4 address for the interface @ifname
* and stores it in @addr
*
* Returns 0 on success, -errno on failure.
*/
#if defined(SIOCGIFADDR) && defined(WITH_STRUCT_IFREQ)
static int
virNetDevGetIPv4AddressIoctl(const char *ifname,
virSocketAddrPtr addr)
{
int fd = -1;
int ret = -1;
struct ifreq ifr;
if ((fd = virNetDevSetupControl(ifname, &ifr)) < 0)
return -1;
if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
virReportSystemError(errno,
_("Unable to get IPv4 address for interface %s via ioctl"),
ifname);
goto cleanup;
}
addr->data.stor.ss_family = AF_INET;
addr->len = sizeof(addr->data.inet4);
memcpy(&addr->data.inet4, &ifr.ifr_addr, addr->len);
ret = 0;
cleanup:
VIR_FORCE_CLOSE(fd);
return ret;
}
#else /* ! SIOCGIFADDR */
static int
virNetDevGetIPv4AddressIoctl(const char *ifname G_GNUC_UNUSED,
virSocketAddrPtr addr G_GNUC_UNUSED)
{
return -2;
}
#endif /* ! SIOCGIFADDR */
/**
* virNetDevGetifaddrsAddress:
* @ifname: name of the interface whose IP address we want
* @addr: filled with the IP address
*
* This function gets the IP address for the interface @ifname
* and stores it in @addr
*
* Returns 0 on success, -1 on failure, -2 on unsupported.
*/
#if WITH_GETIFADDRS
static int
virNetDevGetifaddrsAddress(const char *ifname,
virSocketAddrPtr addr)
{
struct ifaddrs *ifap, *ifa;
int ret = -1;
if (getifaddrs(&ifap) < 0) {
virReportSystemError(errno,
_("Could not get interface list for '%s'"),
ifname);
return -1;
}
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (STRNEQ_NULLABLE(ifa->ifa_name, ifname))
continue;
util: check ifa_addr pointer before accessing its elements Reported by Rafał Wojciechowski <it@rafalwojciechowski.pl>. Thread 1 (Thread 0x7f194b99d700 (LWP 5631)): 0 virNetDevGetifaddrsAddress (addr=0x7f194b99c7c0, ifname=0x7f193400e2b0 "ovirtmgmt") at util/virnetdevip.c:738 1 virNetDevIPAddrGet (ifname=0x7f193400e2b0 "ovirtmgmt", addr=addr@entry=0x7f194b99c7c0) at util/virnetdevip.c:795 2 0x00007f19467800d6 in networkGetNetworkAddress (netname=<optimized out>, netaddr=netaddr@entry=0x7f1924013f18) at network/bridge_driver.c:4780 3 0x00007f193e43a33c in qemuProcessGraphicsSetupNetworkAddress (listenAddr=0x7f19340f7650 "127.0.0.1", glisten=0x7f1924013f10) at qemu/qemu_process.c:4062 4 qemuProcessGraphicsSetupListen (vm=<optimized out>, graphics=0x7f1924014f10, cfg=0x7f1934119f00) at qemu/qemu_process.c:4133 5 qemuProcessSetupGraphics (flags=17, vm=0x7f19240155d0, driver=0x7f193411f1d0) at qemu/qemu_process.c:4196 6 qemuProcessPrepareDomain (conn=conn@entry=0x7f192c00ab50, driver=driver@entry=0x7f193411f1d0, vm=vm@entry=0x7f19240155d0, flags=flags@entry=17) at qemu/qemu_process.c:4969 7 0x00007f193e4417c0 in qemuProcessStart (conn=conn@entry=0x7f192c00ab50, driver=driver@entry=0x7f193411f1d0, vm=0x7f19240155d0,asyncJob=asyncJob@entry=QEMU_ASYNC_JOB_START, migrateFrom=migrateFrom@entry=0x0, migrateFd=migrateFd@entry=-1, migratePath=migratePath@entry=0x0,snapshot=snapshot@entry=0x0, vmop=vmop@entry=VIR_NETDEV_VPORT_PROFILE_OP_CREATE, flags=17, flags@entry=1) at qemu/qemu_process.c:5553 Man page for getifaddrs also states that the "ifa_addr" may contain a null pointer which happens if there is an existing network interface on the host without IP address. Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2017-04-21 08:50:12 +00:00
if (!ifa->ifa_addr)
continue;
util: refactor code to workaround gcc 10.1.0 bug gcc 10.1.0 on Debian sid has a bug where the bounds checking gets confused beteen two branches: In file included from /usr/include/string.h:495, from ../../src/internal.h:28, from ../../src/util/virsocket.h:21, from ../../src/util/virsocketaddr.h:21, from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: In function 'memcpy', inlined from 'virNetDevGetifaddrsAddress' at ../../src/util/virnetdevip.c:914:13, inlined from 'virNetDevIPAddrGet' at ../../src/util/virnetdevip.c:962:16: /usr/include/arm-linux-gnueabihf/bits/string_fortified.h:34:10: error: '__builtin_memcpy' offset [16, 27] from the object at 'addr' is out of the bounds of referenced subobject 'inet4' with type 'struct sockaddr_in' at offset 0 [-Werror=array-bounds] 34 | return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: ../../src/util/virnetdevip.c: In function 'virNetDevIPAddrGet': ../../src/util/virsocketaddr.h:29:28: note: subobject 'inet4' declared here 29 | struct sockaddr_in inet4; | ^~~~~ cc1: all warnings being treated as errors Note the source location is pointing to the "inet6" / AF_INET6 branch of the "if", but is complaining about bounds of the "inet4" field. Changing the code into a switch() is sufficient to avoid triggering the bug and is arguably better code too. Reviewed-by: Laine Stump <laine@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-07-22 14:58:16 +00:00
switch (ifa->ifa_addr->sa_family) {
case AF_INET6:
addr->len = sizeof(addr->data.inet6);
memcpy(&addr->data.inet6, ifa->ifa_addr, addr->len);
util: refactor code to workaround gcc 10.1.0 bug gcc 10.1.0 on Debian sid has a bug where the bounds checking gets confused beteen two branches: In file included from /usr/include/string.h:495, from ../../src/internal.h:28, from ../../src/util/virsocket.h:21, from ../../src/util/virsocketaddr.h:21, from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: In function 'memcpy', inlined from 'virNetDevGetifaddrsAddress' at ../../src/util/virnetdevip.c:914:13, inlined from 'virNetDevIPAddrGet' at ../../src/util/virnetdevip.c:962:16: /usr/include/arm-linux-gnueabihf/bits/string_fortified.h:34:10: error: '__builtin_memcpy' offset [16, 27] from the object at 'addr' is out of the bounds of referenced subobject 'inet4' with type 'struct sockaddr_in' at offset 0 [-Werror=array-bounds] 34 | return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: ../../src/util/virnetdevip.c: In function 'virNetDevIPAddrGet': ../../src/util/virsocketaddr.h:29:28: note: subobject 'inet4' declared here 29 | struct sockaddr_in inet4; | ^~~~~ cc1: all warnings being treated as errors Note the source location is pointing to the "inet6" / AF_INET6 branch of the "if", but is complaining about bounds of the "inet4" field. Changing the code into a switch() is sufficient to avoid triggering the bug and is arguably better code too. Reviewed-by: Laine Stump <laine@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-07-22 14:58:16 +00:00
break;
case AF_INET:
addr->len = sizeof(addr->data.inet4);
memcpy(&addr->data.inet4, ifa->ifa_addr, addr->len);
util: refactor code to workaround gcc 10.1.0 bug gcc 10.1.0 on Debian sid has a bug where the bounds checking gets confused beteen two branches: In file included from /usr/include/string.h:495, from ../../src/internal.h:28, from ../../src/util/virsocket.h:21, from ../../src/util/virsocketaddr.h:21, from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: In function 'memcpy', inlined from 'virNetDevGetifaddrsAddress' at ../../src/util/virnetdevip.c:914:13, inlined from 'virNetDevIPAddrGet' at ../../src/util/virnetdevip.c:962:16: /usr/include/arm-linux-gnueabihf/bits/string_fortified.h:34:10: error: '__builtin_memcpy' offset [16, 27] from the object at 'addr' is out of the bounds of referenced subobject 'inet4' with type 'struct sockaddr_in' at offset 0 [-Werror=array-bounds] 34 | return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: ../../src/util/virnetdevip.c: In function 'virNetDevIPAddrGet': ../../src/util/virsocketaddr.h:29:28: note: subobject 'inet4' declared here 29 | struct sockaddr_in inet4; | ^~~~~ cc1: all warnings being treated as errors Note the source location is pointing to the "inet6" / AF_INET6 branch of the "if", but is complaining about bounds of the "inet4" field. Changing the code into a switch() is sufficient to avoid triggering the bug and is arguably better code too. Reviewed-by: Laine Stump <laine@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-07-22 14:58:16 +00:00
break;
default:
continue;
}
util: refactor code to workaround gcc 10.1.0 bug gcc 10.1.0 on Debian sid has a bug where the bounds checking gets confused beteen two branches: In file included from /usr/include/string.h:495, from ../../src/internal.h:28, from ../../src/util/virsocket.h:21, from ../../src/util/virsocketaddr.h:21, from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: In function 'memcpy', inlined from 'virNetDevGetifaddrsAddress' at ../../src/util/virnetdevip.c:914:13, inlined from 'virNetDevIPAddrGet' at ../../src/util/virnetdevip.c:962:16: /usr/include/arm-linux-gnueabihf/bits/string_fortified.h:34:10: error: '__builtin_memcpy' offset [16, 27] from the object at 'addr' is out of the bounds of referenced subobject 'inet4' with type 'struct sockaddr_in' at offset 0 [-Werror=array-bounds] 34 | return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: ../../src/util/virnetdevip.c: In function 'virNetDevIPAddrGet': ../../src/util/virsocketaddr.h:29:28: note: subobject 'inet4' declared here 29 | struct sockaddr_in inet4; | ^~~~~ cc1: all warnings being treated as errors Note the source location is pointing to the "inet6" / AF_INET6 branch of the "if", but is complaining about bounds of the "inet4" field. Changing the code into a switch() is sufficient to avoid triggering the bug and is arguably better code too. Reviewed-by: Laine Stump <laine@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-07-22 14:58:16 +00:00
addr->data.stor.ss_family = ifa->ifa_addr->sa_family;
ret = 0;
goto cleanup;
}
virReportError(VIR_ERR_INTERNAL_ERROR,
_("no IP address found for interface '%s'"),
ifname);
cleanup:
freeifaddrs(ifap);
return ret;
}
#else /* ! WITH_GETIFADDRS */
static int
virNetDevGetifaddrsAddress(const char *ifname G_GNUC_UNUSED,
virSocketAddrPtr addr G_GNUC_UNUSED)
{
return -2;
}
#endif
/**
* virNetDevIPIPAddrGet:
* @ifname: name of the interface whose IP address we want
* @addr: filled with the IPv4 address
*
* This function gets the IPv4 address for the interface @ifname
* and stores it in @addr
*
* Returns 0 on success, -errno on failure.
*/
int
virNetDevIPAddrGet(const char *ifname,
virSocketAddrPtr addr)
{
int ret;
memset(addr, 0, sizeof(*addr));
addr->data.stor.ss_family = AF_UNSPEC;
if ((ret = virNetDevGetifaddrsAddress(ifname, addr)) != -2)
return ret;
if ((ret = virNetDevGetIPv4AddressIoctl(ifname, addr)) != -2)
return ret;
virReportSystemError(ENOSYS, "%s",
_("Unable to get IP address on this platform"));
return -1;
}
/* manipulating the virNetDevIPRoute object */
void
virNetDevIPRouteFree(virNetDevIPRoutePtr def)
{
if (!def)
return;
VIR_FREE(def->family);
VIR_FREE(def);
}
virSocketAddrPtr
virNetDevIPRouteGetAddress(virNetDevIPRoutePtr def)
{
if (def)
return &def->address;
return NULL;
}
int
virNetDevIPRouteGetPrefix(virNetDevIPRoutePtr def)
{
int prefix = 0;
virSocketAddr zero;
if (!def)
return -1;
/* this creates an all-0 address of the appropriate family */
ignore_value(virSocketAddrParse(&zero,
(VIR_SOCKET_ADDR_IS_FAMILY(&def->address, AF_INET)
? VIR_SOCKET_ADDR_IPV4_ALL
: VIR_SOCKET_ADDR_IPV6_ALL),
VIR_SOCKET_ADDR_FAMILY(&def->address)));
if (virSocketAddrEqual(&def->address, &zero)) {
if (def->has_prefix && def->prefix == 0)
prefix = 0;
else if ((VIR_SOCKET_ADDR_IS_FAMILY(&def->netmask, AF_INET) &&
virSocketAddrEqual(&def->netmask, &zero)))
prefix = 0;
else
prefix = virSocketAddrGetIPPrefix(&def->address, &def->netmask,
def->prefix);
} else {
prefix = virSocketAddrGetIPPrefix(&def->address, &def->netmask,
def->prefix);
}
return prefix;
}
unsigned int
virNetDevIPRouteGetMetric(virNetDevIPRoutePtr def)
{
if (def && def->has_metric && def->metric > 0)
return def->metric;
return 1;
}
virSocketAddrPtr
virNetDevIPRouteGetGateway(virNetDevIPRoutePtr def)
{
if (def)
return &def->gateway;
return NULL;
}
/* manipulating the virNetDevIPInfo object */
void
virNetDevIPInfoClear(virNetDevIPInfoPtr ip)
{
size_t i;
for (i = 0; i < ip->nips; i++)
VIR_FREE(ip->ips[i]);
VIR_FREE(ip->ips);
ip->nips = 0;
for (i = 0; i < ip->nroutes; i++)
virNetDevIPRouteFree(ip->routes[i]);
VIR_FREE(ip->routes);
ip->nroutes = 0;
}
/**
* virNetDevIPInfoAddToDev:
* @ifname: name of device to operate on
* @ipInfo: list of routes and IP addresses to add to this device
*
* All IP routes and IP addresses in ipInfo are added to the named device.
*
* Returns: 0 on success, -1 (and error reported) on failure.
*/
int
virNetDevIPInfoAddToDev(const char *ifname,
virNetDevIPInfo const *ipInfo)
{
size_t i;
int prefix;
g_autofree char *ipStr = NULL;
/* add all IP addresses */
for (i = 0; i < ipInfo->nips; i++) {
virNetDevIPAddrPtr ip = ipInfo->ips[i];
if ((prefix = virSocketAddrGetIPPrefix(&ip->address,
NULL, ip->prefix)) < 0) {
ipStr = virSocketAddrFormat(&ip->address);
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to determine prefix for IP address '%s'"),
NULLSTR(ipStr));
return -1;
}
if (virNetDevIPAddrAdd(ifname, &ip->address, &ip->peer, prefix) < 0)
return -1;
}
/* add all routes */
for (i = 0; i < ipInfo->nroutes; i++) {
virNetDevIPRoutePtr route = ipInfo->routes[i];
if ((prefix = virNetDevIPRouteGetPrefix(route)) < 0) {
ipStr = virSocketAddrFormat(&route->address);
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to determine prefix for route with destination '%s'"),
NULLSTR(ipStr));
return -1;
}
if (virNetDevIPRouteAdd(ifname, &route->address, prefix,
&route->gateway,
virNetDevIPRouteGetMetric(route)) < 0)
return -1;
}
return 0;
}
void
virNetDevIPAddrFree(virNetDevIPAddrPtr ip)
{
VIR_FREE(ip);
}