record/replay: add network support

This patch adds support of recording and replaying network packets in
irount rr mode.

Record and replay for network interactions is performed with the network filter.
Each backend must have its own instance of the replay filter as follows:
 -netdev user,id=net1 -device rtl8139,netdev=net1
 -object filter-replay,id=replay,netdev=net1

Replay network filter is used to record and replay network packets. While
recording the virtual machine this filter puts all packets coming from
the outer world into the log. In replay mode packets from the log are
injected into the network device. All interactions with network backend
in replay mode are disabled.

v5 changes:
 - using iov_to_buf function instead of loop

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>

2 files changed, 93 insertions, 0 deletions

diff --git a/net/Makefile.objs b/net/Makefile.objs
index 2a80df5fa7..2e2fd43014 100644
--- a/net/Makefile.objs
+++ b/net/Makefile.objs
@@ -19,3 +19,4 @@ common-obj-y += filter-mirror.o
 common-obj-y += colo-compare.o
 common-obj-y += colo.o
 common-obj-y += filter-rewriter.o
+common-obj-y += filter-replay.o
diff --git a/net/filter-replay.c b/net/filter-replay.c
new file mode 100644
index 0000000000..cff65f86e5
--- /dev/null
+++ b/net/filter-replay.c
@@ -0,0 +1,92 @@
+/*
+ * filter-replay.c
+ *
+ * Copyright (c) 2010-2016 Institute for System Programming
+ *                         of the Russian Academy of Sciences.
+ *
+ * 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 "clients.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "qemu/error-report.h"
+#include "qemu/iov.h"
+#include "qemu/log.h"
+#include "qemu/timer.h"
+#include "qapi/visitor.h"
+#include "net/filter.h"
+#include "sysemu/replay.h"
+
+#define TYPE_FILTER_REPLAY "filter-replay"
+
+#define FILTER_REPLAY(obj) \
+    OBJECT_CHECK(NetFilterReplayState, (obj), TYPE_FILTER_REPLAY)
+
+struct NetFilterReplayState {
+    NetFilterState nfs;
+    ReplayNetState *rns;
+};
+typedef struct NetFilterReplayState NetFilterReplayState;
+
+static ssize_t filter_replay_receive_iov(NetFilterState *nf,
+                                         NetClientState *sndr,
+                                         unsigned flags,
+                                         const struct iovec *iov,
+                                         int iovcnt, NetPacketSent *sent_cb)
+{
+    NetFilterReplayState *nfrs = FILTER_REPLAY(nf);
+    switch (replay_mode) {
+    case REPLAY_MODE_RECORD:
+        if (nf->netdev == sndr) {
+            replay_net_packet_event(nfrs->rns, flags, iov, iovcnt);
+            return iov_size(iov, iovcnt);
+        }
+        return 0;
+    case REPLAY_MODE_PLAY:
+        /* Drop all packets in replay mode.
+           Packets from the log will be injected by the replay module. */
+        return iov_size(iov, iovcnt);
+    default:
+        /* Pass all the packets. */
+        return 0;
+    }
+}
+
+static void filter_replay_instance_init(Object *obj)
+{
+    NetFilterReplayState *nfrs = FILTER_REPLAY(obj);
+    nfrs->rns = replay_register_net(&nfrs->nfs);
+}
+
+static void filter_replay_instance_finalize(Object *obj)
+{
+    NetFilterReplayState *nfrs = FILTER_REPLAY(obj);
+    replay_unregister_net(nfrs->rns);
+}
+
+static void filter_replay_class_init(ObjectClass *oc, void *data)
+{
+    NetFilterClass *nfc = NETFILTER_CLASS(oc);
+
+    nfc->receive_iov = filter_replay_receive_iov;
+}
+
+static const TypeInfo filter_replay_info = {
+    .name = TYPE_FILTER_REPLAY,
+    .parent = TYPE_NETFILTER,
+    .class_init = filter_replay_class_init,
+    .instance_init = filter_replay_instance_init,
+    .instance_finalize = filter_replay_instance_finalize,
+    .instance_size = sizeof(NetFilterReplayState),
+};
+
+static void filter_replay_register_types(void)
+{
+    type_register_static(&filter_replay_info);
+}
+
+type_init(filter_replay_register_types);