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/*********************************************************
* Copyright (C) 2011-2012 VMware, 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 version 2 and no 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, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*********************************************************/
/*
* vmciRoute.c --
*
* Implementation of VMCI routing rules.
*/
#include "vmci_kernel_if.h"
#include "vm_assert.h"
#include "vmci_defs.h"
#include "vmci_infrastructure.h"
#include "vmciCommonInt.h"
#include "vmciContext.h"
#include "vmciDriver.h"
#include "vmciKernelAPI.h"
#include "vmciRoute.h"
#if defined(VMKERNEL)
# include "vmciVmkInt.h"
# include "vm_libc.h"
# include "helper_ext.h"
#endif
#define LGPFX "VMCIRoute: "
/*
*------------------------------------------------------------------------------
*
* VMCI_Route --
*
* Make a routing decision for the given source and destination handles.
* This will try to determine the route using the handles and the available
* devices.
*
* Result:
* A VMCIRoute value.
*
* Side effects:
* Sets the source context if it is invalid.
*
*------------------------------------------------------------------------------
*/
int
VMCI_Route(VMCIHandle *src, // IN/OUT
const VMCIHandle *dst, // IN
Bool fromGuest, // IN
VMCIRoute *route) // OUT
{
Bool hasHostDevice;
Bool hasGuestDevice;
ASSERT(src);
ASSERT(dst);
ASSERT(route);
*route = VMCI_ROUTE_NONE;
/*
* "fromGuest" is only ever set to TRUE by IOCTL_VMCI_DATAGRAM_SEND (or by
* the vmkernel equivalent), which comes from the VMX, so we know it is
* coming from a guest.
*/
/*
* To avoid inconsistencies, test these once. We will test them again
* when we do the actual send to ensure that we do not touch a non-existent
* device.
*/
hasHostDevice = VMCI_HostPersonalityActive();
hasGuestDevice = VMCI_GuestPersonalityActive();
/* Must have a valid destination context. */
if (VMCI_INVALID_ID == dst->context) {
return VMCI_ERROR_INVALID_ARGS;
}
/* Anywhere to hypervisor. */
if (VMCI_HYPERVISOR_CONTEXT_ID == dst->context) {
/*
* If this message already came from a guest then we cannot send it
* to the hypervisor. It must come from a local client.
*/
if (fromGuest) {
return VMCI_ERROR_DST_UNREACHABLE;
}
/* We must be acting as a guest in order to send to the hypervisor. */
if (!hasGuestDevice) {
return VMCI_ERROR_DEVICE_NOT_FOUND;
}
/* And we cannot send if the source is the host context. */
if (VMCI_HOST_CONTEXT_ID == src->context) {
return VMCI_ERROR_INVALID_ARGS;
}
/*
* If the client passed the ANON source handle then respect it (both
* context and resource are invalid). However, if they passed only
* an invalid context, then they probably mean ANY, in which case we
* should set the real context here before passing it down.
*/
if (VMCI_INVALID_ID == src->context && VMCI_INVALID_ID != src->resource) {
src->context = vmci_get_context_id();
}
/* Send from local client down to the hypervisor. */
*route = VMCI_ROUTE_AS_GUEST;
return VMCI_SUCCESS;
}
/* Anywhere to local client on host. */
if (VMCI_HOST_CONTEXT_ID == dst->context) {
/*
* If it is not from a guest but we are acting as a guest, then we need
* to send it down to the host. Note that if we are also acting as a
* host then this will prevent us from sending from local client to
* local client, but we accept that restriction as a way to remove
* any ambiguity from the host context.
*/
if (src->context == VMCI_HYPERVISOR_CONTEXT_ID) {
/*
* If the hypervisor is the source, this is host local
* communication. The hypervisor may send vmci event
* datagrams to the host itself, but it will never send
* datagrams to an "outer host" through the guest device.
*/
if (hasHostDevice) {
*route = VMCI_ROUTE_AS_HOST;
return VMCI_SUCCESS;
} else {
return VMCI_ERROR_DEVICE_NOT_FOUND;
}
}
if (!fromGuest && hasGuestDevice) {
/* If no source context then use the current. */
if (VMCI_INVALID_ID == src->context) {
src->context = vmci_get_context_id();
}
/* Send it from local client down to the host. */
*route = VMCI_ROUTE_AS_GUEST;
return VMCI_SUCCESS;
}
/*
* Otherwise we already received it from a guest and it is destined
* for a local client on this host, or it is from another local client
* on this host. We must be acting as a host to service it.
*/
if (!hasHostDevice) {
return VMCI_ERROR_DEVICE_NOT_FOUND;
}
if (VMCI_INVALID_ID == src->context) {
/*
* If it came from a guest then it must have a valid context.
* Otherwise we can use the host context.
*/
if (fromGuest) {
return VMCI_ERROR_INVALID_ARGS;
}
src->context = VMCI_HOST_CONTEXT_ID;
}
/* Route to local client. */
*route = VMCI_ROUTE_AS_HOST;
return VMCI_SUCCESS;
}
/* If we are acting as a host then this might be destined for a guest. */
if (hasHostDevice) {
/* It will have a context if it is meant for a guest. */
if (VMCIContext_Exists(dst->context)) {
if (VMCI_INVALID_ID == src->context) {
/*
* If it came from a guest then it must have a valid context.
* Otherwise we can use the host context.
*/
if (fromGuest) {
return VMCI_ERROR_INVALID_ARGS;
}
src->context = VMCI_HOST_CONTEXT_ID;
} else if (VMCI_CONTEXT_IS_VM(src->context) &&
src->context != dst->context) {
/*
* VM to VM communication is not allowed. Since we catch
* all communication destined for the host above, this
* must be destined for a VM since there is a valid
* context.
*/
ASSERT(VMCI_CONTEXT_IS_VM(dst->context));
return VMCI_ERROR_DST_UNREACHABLE;
}
/* Pass it up to the guest. */
*route = VMCI_ROUTE_AS_HOST;
return VMCI_SUCCESS;
} else if (!hasGuestDevice) {
/*
* The host is attempting to reach a CID without an active context, and
* we can't send it down, since we have no guest device.
*/
return VMCI_ERROR_DST_UNREACHABLE;
}
}
/*
* We must be a guest trying to send to another guest, which means
* we need to send it down to the host. We do not filter out VM to
* VM communication here, since we want to be able to use the guest
* driver on older versions that do support VM to VM communication.
*/
if (!hasGuestDevice) {
/*
* Ending up here means we have neither guest nor host device. That
* shouldn't happen, since any VMCI client in the kernel should have done
* a successful VMCI_DeviceGet.
*/
ASSERT(FALSE);
return VMCI_ERROR_DEVICE_NOT_FOUND;
}
/* If no source context then use the current context. */
if (VMCI_INVALID_ID == src->context) {
src->context = vmci_get_context_id();
}
/*
* Send it from local client down to the host, which will route it to
* the other guest for us.
*/
*route = VMCI_ROUTE_AS_GUEST;
return VMCI_SUCCESS;
}
/*
*------------------------------------------------------------------------------
*
* VMCI_RouteString --
*
* Get a string for the given route.
*
* Result:
* A string representing the route, if the route is valid, otherwise an
* empty string.
*
* Side effects:
* None.
*
*------------------------------------------------------------------------------
*/
const char *
VMCI_RouteString(VMCIRoute route) // IN
{
const char *vmciRouteStrings[] = {
"none",
"as host",
"as guest",
};
if (route >= VMCI_ROUTE_NONE && route <= VMCI_ROUTE_AS_GUEST) {
return vmciRouteStrings[route];
}
return "";
}
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