filter: Add 'status' property for filter object

With this property, users can control if this filter is 'on'
or 'off'. The default behavior for filter is 'on'.

For some types of filters, they may need to react to status changing,
So here, we introduced status changing callback/notifier for filter class.

We will skip the disabled ('off') filter when delivering packets in net layer.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Yang Hongyang <hongyang.yang@easystack.cn>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/net/filter.c b/net/filter.c
index 7cdbc6c615..a08ef68ae6 100644
--- a/net/filter.c
+++ b/net/filter.c
@@ -17,6 +17,11 @@
 #include "qom/object_interfaces.h"
 #include "qemu/iov.h"
 
+static inline bool qemu_can_skip_netfilter(NetFilterState *nf)
+{
+    return !nf->on;
+}
+
 ssize_t qemu_netfilter_receive(NetFilterState *nf,
                                NetFilterDirection direction,
                                NetClientState *sender,
@@ -25,6 +30,9 @@ ssize_t qemu_netfilter_receive(NetFilterState *nf,
                                int iovcnt,
                                NetPacketSent *sent_cb)
 {
+    if (qemu_can_skip_netfilter(nf)) {
+        return 0;
+    }
     if (nf->direction == direction ||
         nf->direction == NET_FILTER_DIRECTION_ALL) {
         return NETFILTER_GET_CLASS(OBJECT(nf))->receive_iov(
@@ -134,8 +142,38 @@ static void netfilter_set_direction(Object *obj, int direction, Error **errp)
     nf->direction = direction;
 }
 
+static char *netfilter_get_status(Object *obj, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(obj);
+
+    return nf->on ? g_strdup("on") : g_strdup("off");
+}
+
+static void netfilter_set_status(Object *obj, const char *str, Error **errp)
+{
+    NetFilterState *nf = NETFILTER(obj);
+    NetFilterClass *nfc = NETFILTER_GET_CLASS(obj);
+
+    if (strcmp(str, "on") && strcmp(str, "off")) {
+        error_setg(errp, "Invalid value for netfilter status, "
+                         "should be 'on' or 'off'");
+        return;
+    }
+    if (nf->on == !strcmp(str, "on")) {
+        return;
+    }
+    nf->on = !nf->on;
+    if (nfc->status_changed) {
+        nfc->status_changed(nf, errp);
+    }
+}
+
 static void netfilter_init(Object *obj)
 {
+    NetFilterState *nf = NETFILTER(obj);
+
+    nf->on = true;
+
     object_property_add_str(obj, "netdev",
                             netfilter_get_netdev_id, netfilter_set_netdev_id,
                             NULL);
@@ -143,6 +181,9 @@ static void netfilter_init(Object *obj)
                              NetFilterDirection_lookup,
                              netfilter_get_direction, netfilter_set_direction,
                              NULL);
+    object_property_add_str(obj, "status",
+                            netfilter_get_status, netfilter_set_status,
+                            NULL);
 }
 
 static void netfilter_complete(UserCreatable *uc, Error **errp)