init/cleanup of netfilter object

Add a netfilter object based on QOM.

A netfilter is attached to a netdev, captures all network packets
that pass through the netdev. When we delete the netdev, we also
delete the netfilter object attached to it, because if the netdev is
removed, the filter which attached to it is useless.

Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

include/net/filter.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Author: Yang Hongyang <yanghy@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_NET_FILTER_H
+#define QEMU_NET_FILTER_H
+
+#include "qom/object.h"
+#include "qemu-common.h"
+#include "qemu/typedefs.h"
+#include "net/queue.h"
+
+#define TYPE_NETFILTER "netfilter"
+#define NETFILTER(obj) \
+    OBJECT_CHECK(NetFilterState, (obj), TYPE_NETFILTER)
+#define NETFILTER_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(NetFilterClass, (obj), TYPE_NETFILTER)
+#define NETFILTER_CLASS(klass) \
+    OBJECT_CLASS_CHECK(NetFilterClass, (klass), TYPE_NETFILTER)
+
+typedef void (FilterSetup) (NetFilterState *nf, Error **errp);
+typedef void (FilterCleanup) (NetFilterState *nf);
+/*
+ * Return:
+ *   0: finished handling the packet, we should continue
+ *   size: filter stolen this packet, we stop pass this packet further
+ */
+typedef ssize_t (FilterReceiveIOV)(NetFilterState *nc,
+                                   NetClientState *sender,
+                                   unsigned flags,
+                                   const struct iovec *iov,
+                                   int iovcnt,
+                                   NetPacketSent *sent_cb);
+
+typedef struct NetFilterClass {
+    ObjectClass parent_class;
+
+    /* optional */
+    FilterSetup *setup;
+    FilterCleanup *cleanup;
+    /* mandatory */
+    FilterReceiveIOV *receive_iov;
+} NetFilterClass;
+
+
+struct NetFilterState {
+    /* private */
+    Object parent;
+
+    /* protected */
+    char *netdev_id;
+    NetClientState *netdev;
+    NetFilterDirection direction;
+    QTAILQ_ENTRY(NetFilterState) next;
+};
+
+#endif /* QEMU_NET_FILTER_H */

include/net/net.h

@@ -92,6 +92,7 @@ struct NetClientState {
     NetClientDestructor *destructor;
     unsigned int queue_index;
     unsigned rxfilter_notify_enabled:1;
+    QTAILQ_HEAD(, NetFilterState) filters;
 };
 
 typedef struct NICState {

include/qemu/typedefs.h

@@ -45,6 +45,7 @@ typedef struct Monitor Monitor;
 typedef struct MouseTransformInfo MouseTransformInfo;
 typedef struct MSIMessage MSIMessage;
 typedef struct NetClientState NetClientState;
+typedef struct NetFilterState NetFilterState;
 typedef struct NICInfo NICInfo;
 typedef struct PcGuestInfo PcGuestInfo;
 typedef struct PCIBridge PCIBridge;

net/Makefile.objs

@@ -13,3 +13,4 @@ common-obj-$(CONFIG_HAIKU) += tap-haiku.o
 common-obj-$(CONFIG_SLIRP) += slirp.o
 common-obj-$(CONFIG_VDE) += vde.o
 common-obj-$(CONFIG_NETMAP) += netmap.o
+common-obj-y += filter.o

net/filter.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Author: Yang Hongyang <yanghy@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+#include "qapi/qmp/qerror.h"
+#include "qemu/error-report.h"
+
+#include "net/filter.h"
+#include "net/net.h"
+#include "net/vhost_net.h"
+#include "qom/object_interfaces.h"
+
+static char *netfilter_get_netdev_id(Object *obj, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(obj);
+
+    return g_strdup(nf->netdev_id);
+}
+
+static void netfilter_set_netdev_id(Object *obj, const char *str, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(obj);
+
+    nf->netdev_id = g_strdup(str);
+}
+
+static int netfilter_get_direction(Object *obj, Error **errp G_GNUC_UNUSED)
+{
+    NetFilterState *nf = NETFILTER(obj);
+    return nf->direction;
+}
+
+static void netfilter_set_direction(Object *obj, int direction, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(obj);
+    nf->direction = direction;
+}
+
+static void netfilter_init(Object *obj)
+{
+    object_property_add_str(obj, "netdev",
+                            netfilter_get_netdev_id, netfilter_set_netdev_id,
+                            NULL);
+    object_property_add_enum(obj, "queue", "NetFilterDirection",
+                             NetFilterDirection_lookup,
+                             netfilter_get_direction, netfilter_set_direction,
+                             NULL);
+}
+
+static void netfilter_complete(UserCreatable *uc, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(uc);
+    NetClientState *ncs[MAX_QUEUE_NUM];
+    NetFilterClass *nfc = NETFILTER_GET_CLASS(uc);
+    int queues;
+    Error *local_err = NULL;
+
+    if (!nf->netdev_id) {
+        error_setg(errp, "Parameter 'netdev' is required");
+        return;
+    }
+
+    queues = qemu_find_net_clients_except(nf->netdev_id, ncs,
+                                          NET_CLIENT_OPTIONS_KIND_NIC,
+                                          MAX_QUEUE_NUM);
+    if (queues < 1) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "netdev",
+                   "a network backend id");
+        return;
+    } else if (queues > 1) {
+        error_setg(errp, "multiqueue is not supported");
+        return;
+    }
+
+    if (get_vhost_net(ncs[0])) {
+        error_setg(errp, "Vhost is not supported");
+        return;
+    }
+
+    nf->netdev = ncs[0];
+
+    if (nfc->setup) {
+        nfc->setup(nf, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+    QTAILQ_INSERT_TAIL(&nf->netdev->filters, nf, next);
+}
+
+static void netfilter_finalize(Object *obj)
+{
+    NetFilterState *nf = NETFILTER(obj);
+    NetFilterClass *nfc = NETFILTER_GET_CLASS(obj);
+
+    if (nfc->cleanup) {
+        nfc->cleanup(nf);
+    }
+
+    if (nf->netdev && !QTAILQ_EMPTY(&nf->netdev->filters)) {
+        QTAILQ_REMOVE(&nf->netdev->filters, nf, next);
+    }
+}
+
+static void netfilter_class_init(ObjectClass *oc, void *data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+
+    ucc->complete = netfilter_complete;
+}
+
+static const TypeInfo netfilter_info = {
+    .name = TYPE_NETFILTER,
+    .parent = TYPE_OBJECT,
+    .abstract = true,
+    .class_size = sizeof(NetFilterClass),
+    .class_init = netfilter_class_init,
+    .instance_size = sizeof(NetFilterState),
+    .instance_init = netfilter_init,
+    .instance_finalize = netfilter_finalize,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+static void register_types(void)
+{
+    type_register_static(&netfilter_info);
+}
+
+type_init(register_types);

net/net.c

@@ -44,6 +44,7 @@
 #include "qapi/opts-visitor.h"
 #include "qapi/dealloc-visitor.h"
 #include "sysemu/sysemu.h"
+#include "net/filter.h"
 
 /* Net bridge is currently not supported for W32. */
 #if !defined(_WIN32)
@@ -287,6 +288,7 @@ static void qemu_net_client_setup(NetClientState *nc,
 
     nc->incoming_queue = qemu_new_net_queue(nc);
     nc->destructor = destructor;
+    QTAILQ_INIT(&nc->filters);
 }
 
 NetClientState *qemu_new_net_client(NetClientInfo *info,
@@ -384,6 +386,7 @@ void qemu_del_net_client(NetClientState *nc)
 {
     NetClientState *ncs[MAX_QUEUE_NUM];
     int queues, i;
+    NetFilterState *nf, *next;
 
     assert(nc->info->type != NET_CLIENT_OPTIONS_KIND_NIC);
 
@@ -395,6 +398,10 @@ void qemu_del_net_client(NetClientState *nc)
                                           MAX_QUEUE_NUM);
     assert(queues != 0);
 
+    QTAILQ_FOREACH_SAFE(nf, &nc->filters, next, next) {
+        object_unparent(OBJECT(nf));
+    }
+
     /* If there is a peer NIC, delete and cleanup client, but do not free. */
     if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
         NICState *nic = qemu_get_nic(nc->peer);

qapi-schema.json

@@ -2587,6 +2587,26 @@
     'id':   'str',
     'opts': 'NetClientOptions' } }
 
+##
+# @NetFilterDirection
+#
+# Indicates whether a netfilter is attached to a netdev's transmit queue or
+# receive queue or both.
+#
+# @all: the filter is attached both to the receive and the transmit
+#       queue of the netdev (default).
+#
+# @rx: the filter is attached to the receive queue of the netdev,
+#      where it will receive packets sent to the netdev.
+#
+# @tx: the filter is attached to the transmit queue of the netdev,
+#      where it will receive packets sent by the netdev.
+#
+# Since 2.5
+##
+{ 'enum': 'NetFilterDirection',
+  'data': [ 'all', 'rx', 'tx' ] }
+
 ##
 # @InetSocketAddress
 #