filter-rewriter: introduce filter-rewriter initialization

Filter-rewriter is a part of COLO project.
It will rewrite some of secondary packet to make
secondary guest's tcp connection established successfully.
In this module we will rewrite tcp packet's ack to the secondary
from primary,and rewrite tcp packet's seq to the primary from
secondary.

usage:

colo secondary:
-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
-object filter-rewriter,id=rew0,netdev=hn0,queue=all

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

2 files changed, 106 insertions, 0 deletions

diff --git a/net/Makefile.objs b/net/Makefile.objs
index beb504b..2a80df5 100644
--- a/net/Makefile.objs
+++ b/net/Makefile.objs
@@ -18,3 +18,4 @@ common-obj-y += filter-buffer.o
 common-obj-y += filter-mirror.o
 common-obj-y += colo-compare.o
 common-obj-y += colo.o
+common-obj-y += filter-rewriter.o
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
new file mode 100644
index 0000000..de29f07
--- /dev/null
+++ b/net/filter-rewriter.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2016 FUJITSU LIMITED
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * Author: Zhang Chen <zhangchen.fnst@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/osdep.h"
+#include "net/colo.h"
+#include "net/filter.h"
+#include "net/net.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "qapi-visit.h"
+#include "qom/object.h"
+#include "qemu/main-loop.h"
+#include "qemu/iov.h"
+#include "net/checksum.h"
+
+#define FILTER_COLO_REWRITER(obj) \
+    OBJECT_CHECK(RewriterState, (obj), TYPE_FILTER_REWRITER)
+
+#define TYPE_FILTER_REWRITER "filter-rewriter"
+
+typedef struct RewriterState {
+    NetFilterState parent_obj;
+    NetQueue *incoming_queue;
+    /* hashtable to save connection */
+    GHashTable *connection_track_table;
+} RewriterState;
+
+static void filter_rewriter_flush(NetFilterState *nf)
+{
+    RewriterState *s = FILTER_COLO_REWRITER(nf);
+
+    if (!qemu_net_queue_flush(s->incoming_queue)) {
+        /* Unable to empty the queue, purge remaining packets */
+        qemu_net_queue_purge(s->incoming_queue, nf->netdev);
+    }
+}
+
+static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
+                                         NetClientState *sender,
+                                         unsigned flags,
+                                         const struct iovec *iov,
+                                         int iovcnt,
+                                         NetPacketSent *sent_cb)
+{
+    /*
+     * if we get tcp packet
+     * we will rewrite it to make secondary guest's
+     * connection established successfully
+     */
+    return 0;
+}
+
+static void colo_rewriter_cleanup(NetFilterState *nf)
+{
+    RewriterState *s = FILTER_COLO_REWRITER(nf);
+
+    /* flush packets */
+    if (s->incoming_queue) {
+        filter_rewriter_flush(nf);
+        g_free(s->incoming_queue);
+    }
+}
+
+static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
+{
+    RewriterState *s = FILTER_COLO_REWRITER(nf);
+
+    s->connection_track_table = g_hash_table_new_full(connection_key_hash,
+                                                      connection_key_equal,
+                                                      g_free,
+                                                      connection_destroy);
+    s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
+}
+
+static void colo_rewriter_class_init(ObjectClass *oc, void *data)
+{
+    NetFilterClass *nfc = NETFILTER_CLASS(oc);
+
+    nfc->setup = colo_rewriter_setup;
+    nfc->cleanup = colo_rewriter_cleanup;
+    nfc->receive_iov = colo_rewriter_receive_iov;
+}
+
+static const TypeInfo colo_rewriter_info = {
+    .name = TYPE_FILTER_REWRITER,
+    .parent = TYPE_NETFILTER,
+    .class_init = colo_rewriter_class_init,
+    .instance_size = sizeof(RewriterState),
+};
+
+static void register_types(void)
+{
+    type_register_static(&colo_rewriter_info);
+}
+
+type_init(register_types);