[Qemu-devel] [PATCH V13 09/12] filter-rewriter: introduce filter-rewriter initialization

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

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>
---
 net/Makefile.objs     |   1 +
 net/filter-rewriter.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-options.hx       |  13 ++++++
 vl.c                  |   3 +-
 4 files changed, 126 insertions(+), 1 deletion(-)
 create mode 100644 net/filter-rewriter.c

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..e23c21d
--- /dev/null
+++ b/net/filter-rewriter.c
@@ -0,0 +1,110 @@
+/*
+ * 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"
+
+enum {
+    PRIMARY = 0,
+    SECONDARY,
+};
+
+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);
diff --git a/qemu-options.hx b/qemu-options.hx
index 87fbba3..5cd50a8 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3880,6 +3880,19 @@ Create a filter-redirector we need to differ outdev id from indev id, id can not
 be the same. we can just use indev or outdev, but at least one of indev or outdev
 need to be specified.
 
+@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},rewriter-mode=@var{mode}[,queue=@var{all|rx|tx}]
+
+Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
+secondary from primary to keep secondary tcp connection,and rewrite
+tcp packet to primary from secondary make tcp packet can be handled by
+client.
+
+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
+
 @item -object filter-dump,id=@var{id},netdev=@var{dev},file=@var{filename}][,maxlen=@var{len}]
 
 Dump the network traffic on netdev @var{dev} to the file specified by
diff --git a/vl.c b/vl.c
index e73a1d1..cda24ce 100644
--- a/vl.c
+++ b/vl.c
@@ -2807,7 +2807,8 @@ static bool object_create_initial(const char *type)
         g_str_equal(type, "filter-dump") ||
         g_str_equal(type, "filter-mirror") ||
         g_str_equal(type, "filter-redirector") ||
-        g_str_equal(type, "colo-compare")) {
+        g_str_equal(type, "colo-compare") ||
+        g_str_equal(type, "filter-rewriter")) {
         return false;
     }
 
-- 
2.7.4