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util:veth: Create veth device pair by netlink

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When netlink is supported, use netlink to create veth device pair
rather than 'ip link' command.

Signed-off-by: Shi Lei <shi_lei@massclouds.com>
Reviewed-by: Laine Stump <laine@redhat.com>
This commit is contained in:
Shi Lei 2020-12-16 14:01:05 +08:00 committed by Laine Stump
parent 1e0e535b02
commit 87502a35ae
1 changed files with 92 additions and 74 deletions
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166
src/util/virnetdevveth.c
View File

@ -27,93 +27,45 @@
#include "virfile.h"
#include "virstring.h"
#include "virnetdev.h"
#include "virnetlink.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.netdevveth");
/**
* virNetDevVethCreate:
* @veth1: pointer to name for parent end of veth pair
* @veth2: pointer to return name for container end of veth pair
*
* Creates a veth device pair using the ip command:
* ip link add veth1 type veth peer name veth2
* If veth1 points to NULL on entry, it will be a valid interface on
* return. veth2 should point to NULL on entry.
*
* NOTE: If veth1 and veth2 names are not specified, ip will auto assign
* names. There seems to be two problems here -
* 1) There doesn't seem to be a way to determine the names of the
* devices that it creates. They show up in ip link show and
* under /sys/class/net/ however there is no guarantee that they
* are the devices that this process just created.
* 2) Once one of the veth devices is moved to another namespace, it
* is no longer visible in the parent namespace. This seems to
* confuse the name assignment causing it to fail with File exists.
* Because of these issues, this function currently allocates names
* prior to using the ip command, and returns any allocated names
* to the caller.
*
* Returns 0 on success or -1 in case of error
*/
int virNetDevVethCreate(char** veth1, char** veth2)
#if defined(WITH_LIBNL)
static int
virNetDevVethCreateInternal(const char *veth1, const char *veth2)
{
int status;
g_autofree char *veth1auto = NULL;
g_autofree char *veth2auto = NULL;
g_autoptr(virCommand) cmd = NULL;
int status; /* Just ignore it */
virNetlinkNewLinkData data = { .veth_peer = veth2 };
if (virNetDevGenerateName(&veth1auto, VIR_NET_DEV_GEN_NAME_VNET) < 0)
return -1;
if (virNetDevGenerateName(&veth2auto, VIR_NET_DEV_GEN_NAME_VNET) < 0)
return -1;
cmd = virCommandNew("ip");
virCommandAddArgList(cmd, "link", "add",
*veth1 ? *veth1 : veth1auto,
"type", "veth", "peer", "name",
*veth2 ? *veth2 : veth2auto,
NULL);
if (virCommandRun(cmd, &status) < 0 || status) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("Failed to allocate free veth pair"));
return -1;
}
VIR_DEBUG("create veth host: %s guest: %s: %d",
*veth1 ? *veth1 : veth1auto,
*veth2 ? *veth2 : veth2auto,
status);
if (veth1auto)
*veth1 = g_steal_pointer(&veth1auto);
if (veth2auto)
*veth2 = g_steal_pointer(&veth2auto);
VIR_DEBUG("Create Host: %s guest: %s", *veth1, *veth2);
return 0;
return virNetlinkNewLink(veth1, "veth", &data, &status);
}
/**
* virNetDevVethDelete:
* @veth: name for one end of veth pair
*
* This will delete both veth devices in a pair. Only one end needs to
* be specified. The ip command will identify and delete the other veth
* device as well.
* ip link del veth
*
* Returns 0 on success or -1 in case of error
*/
int virNetDevVethDelete(const char *veth)
static int
virNetDevVethDeleteInternal(const char *veth)
{
return virNetlinkDelLink(veth, NULL);
}
#else
static int
virNetDevVethCreateInternal(const char *veth1, const char *veth2)
{
g_autoptr(virCommand) cmd = virCommandNew("ip");
virCommandAddArgList(cmd, "link", "add", veth1, "type", "veth",
"peer", "name", veth2, NULL);
return virCommandRun(cmd, NULL);
}
static int
virNetDevVethDeleteInternal(const char *veth)
{
int status;
g_autoptr(virCommand) cmd = virCommandNewArgList("ip", "link",
"del", veth, NULL);
"del", veth, NULL);
if (virCommandRun(cmd, &status) < 0)
return -1;
@ -130,3 +82,69 @@ int virNetDevVethDelete(const char *veth)
return 0;
}
#endif /* WITH_LIBNL */
/**
* virNetDevVethCreate:
* @veth1: pointer to name for one end of veth pair
* @veth2: pointer to name for another end of veth pair
*
* Creates a veth device pair.
*
* NOTE: If veth1 and veth2 names are not specified, ip will auto assign
* names. There seems to be two problems here -
* 1) There doesn't seem to be a way to determine the names of the
* devices that it creates. They show up in ip link show and
* under /sys/class/net/ however there is no guarantee that they
* are the devices that this process just created.
* 2) Once one of the veth devices is moved to another namespace, it
* is no longer visible in the parent namespace. This seems to
* confuse the name assignment causing it to fail with File exists.
* Because of these issues, this function currently allocates names
* prior to using the ip command, and returns any allocated names
* to the caller.
*
* Returns 0 on success or -1 in case of error
*/
int virNetDevVethCreate(char **veth1, char **veth2)
{
const char *orig1 = *veth1;
const char *orig2 = *veth2;
if (virNetDevGenerateName(veth1, VIR_NET_DEV_GEN_NAME_VNET) < 0)
goto cleanup;
if (virNetDevGenerateName(veth2, VIR_NET_DEV_GEN_NAME_VNET) < 0)
goto cleanup;
if (virNetDevVethCreateInternal(*veth1, *veth2) < 0)
goto cleanup;
VIR_DEBUG("Create Host: %s guest: %s", *veth1, *veth2);
return 0;
cleanup:
if (orig1 == NULL)
VIR_FREE(*veth1);
if (orig2 == NULL)
VIR_FREE(*veth2);
return -1;
}
/**
* virNetDevVethDelete:
* @veth: name for one end of veth pair
*
* This will delete both veth devices in a pair. Only one end needs to
* be specified. The ip command will identify and delete the other veth
* device as well.
* ip link del veth
*
* Returns 0 on success or -1 in case of error
*/
int virNetDevVethDelete(const char *veth)
{
return virNetDevVethDeleteInternal(veth);
}