diff options
Diffstat (limited to 'drivers/misc/vmw_vmci/vmci_route.c')
| -rw-r--r-- | drivers/misc/vmw_vmci/vmci_route.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/misc/vmw_vmci/vmci_route.c b/drivers/misc/vmw_vmci/vmci_route.c new file mode 100644 index 000000000..91090658b --- /dev/null +++ b/drivers/misc/vmw_vmci/vmci_route.c @@ -0,0 +1,226 @@ +/* + * VMware VMCI Driver + * + * Copyright (C) 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. + */ + +#include <linux/vmw_vmci_defs.h> +#include <linux/vmw_vmci_api.h> + +#include "vmci_context.h" +#include "vmci_driver.h" +#include "vmci_route.h" + +/* + * 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. Will set the source context if it is invalid. + */ +int vmci_route(struct vmci_handle *src, + const struct vmci_handle *dst, + bool from_guest, + enum vmci_route *route) +{ + bool has_host_device = vmci_host_code_active(); + bool has_guest_device = vmci_guest_code_active(); + + *route = VMCI_ROUTE_NONE; + + /* + * "from_guest" 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. + */ + + /* 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 (from_guest) + return VMCI_ERROR_DST_UNREACHABLE; + + /* + * We must be acting as a guest in order to send to + * the hypervisor. + */ + if (!has_guest_device) + 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 (has_host_device) { + *route = VMCI_ROUTE_AS_HOST; + return VMCI_SUCCESS; + } else { + return VMCI_ERROR_DEVICE_NOT_FOUND; + } + } + + if (!from_guest && has_guest_device) { + /* 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 (!has_host_device) + 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 (from_guest) + 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 (has_host_device) { + /* It will have a context if it is meant for a guest. */ + if (vmci_ctx_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 (from_guest) + 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. + */ + + return VMCI_ERROR_DST_UNREACHABLE; + } + + /* Pass it up to the guest. */ + *route = VMCI_ROUTE_AS_HOST; + return VMCI_SUCCESS; + } else if (!has_guest_device) { + /* + * 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 (!has_guest_device) { + /* + * Ending up here means we have neither guest nor host + * device. + */ + 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; +} |