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>

5 files changed, 125 insertions, 1 deletions

diff --git a/replay/Makefile.objs b/replay/Makefile.objs
index c8ad3eb..b2afd40 100644
--- a/replay/Makefile.objs
+++ b/replay/Makefile.objs
@@ -5,3 +5,4 @@ common-obj-y += replay-time.o
 common-obj-y += replay-input.o
 common-obj-y += replay-char.o
 common-obj-y += replay-snapshot.o
+common-obj-y += replay-net.o
diff --git a/replay/replay-events.c b/replay/replay-events.c
index c513913..94a6dcc 100644
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -54,6 +54,9 @@ static void replay_run_event(Event *event)
     case REPLAY_ASYNC_EVENT_BLOCK:
         aio_bh_call(event->opaque);
         break;
+    case REPLAY_ASYNC_EVENT_NET:
+        replay_event_net_run(event->opaque);
+        break;
     default:
         error_report("Replay: invalid async event ID (%d) in the queue",
                     event->event_kind);
@@ -189,6 +192,9 @@ static void replay_save_event(Event *event, int checkpoint)
         case REPLAY_ASYNC_EVENT_BLOCK:
             replay_put_qword(event->id);
             break;
+        case REPLAY_ASYNC_EVENT_NET:
+            replay_event_net_save(event->opaque);
+            break;
         default:
             error_report("Unknown ID %" PRId64 " of replay event", event->id);
             exit(1);
@@ -252,6 +258,11 @@ static Event *replay_read_event(int checkpoint)
             read_id = replay_get_qword();
         }
         break;
+    case REPLAY_ASYNC_EVENT_NET:
+        event = g_malloc0(sizeof(Event));
+        event->event_kind = read_event_kind;
+        event->opaque = replay_event_net_load();
+        return event;
     default:
         error_report("Unknown ID %d of replay event", read_event_kind);
         exit(1);
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 9117e44..c26d079 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -50,6 +50,7 @@ enum ReplayAsyncEventKind {
     REPLAY_ASYNC_EVENT_INPUT_SYNC,
     REPLAY_ASYNC_EVENT_CHAR_READ,
     REPLAY_ASYNC_EVENT_BLOCK,
+    REPLAY_ASYNC_EVENT_NET,
     REPLAY_ASYNC_COUNT
 };
 
@@ -161,6 +162,15 @@ void replay_event_char_read_save(void *opaque);
 /*! Reads char event read from the file. */
 void *replay_event_char_read_load(void);
 
+/* Network devices */
+
+/*! Called to run network event. */
+void replay_event_net_run(void *opaque);
+/*! Writes network event to the file. */
+void replay_event_net_save(void *opaque);
+/*! Reads network from the file. */
+void *replay_event_net_load(void);
+
 /* VMState-related functions */
 
 /* Registers replay VMState.
diff --git a/replay/replay-net.c b/replay/replay-net.c
new file mode 100644
index 0000000..80b7054
--- /dev/null
+++ b/replay/replay-net.c
@@ -0,0 +1,102 @@
+/*
+ * replay-net.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 "qemu/error-report.h"
+#include "sysemu/replay.h"
+#include "replay-internal.h"
+#include "sysemu/sysemu.h"
+#include "net/net.h"
+#include "net/filter.h"
+#include "qemu/iov.h"
+
+struct ReplayNetState {
+    NetFilterState *nfs;
+    int id;
+};
+
+typedef struct NetEvent {
+    uint8_t id;
+    uint32_t flags;
+    uint8_t *data;
+    size_t size;
+} NetEvent;
+
+static NetFilterState **network_filters;
+static int network_filters_count;
+
+ReplayNetState *replay_register_net(NetFilterState *nfs)
+{
+    ReplayNetState *rns = g_new0(ReplayNetState, 1);
+    rns->nfs = nfs;
+    rns->id = network_filters_count++;
+    network_filters = g_realloc(network_filters,
+                                network_filters_count
+                                    * sizeof(*network_filters));
+    network_filters[network_filters_count - 1] = nfs;
+    return rns;
+}
+
+void replay_unregister_net(ReplayNetState *rns)
+{
+    network_filters[rns->id] = NULL;
+    g_free(rns);
+}
+
+void replay_net_packet_event(ReplayNetState *rns, unsigned flags,
+                             const struct iovec *iov, int iovcnt)
+{
+    NetEvent *event = g_new(NetEvent, 1);
+    event->flags = flags;
+    event->data = g_malloc(iov_size(iov, iovcnt));
+    event->size = iov_size(iov, iovcnt);
+    event->id = rns->id;
+    iov_to_buf(iov, iovcnt, 0, event->data, event->size);
+
+    replay_add_event(REPLAY_ASYNC_EVENT_NET, event, NULL, 0);
+}
+
+void replay_event_net_run(void *opaque)
+{
+    NetEvent *event = opaque;
+    struct iovec iov = {
+        .iov_base = (void *)event->data,
+        .iov_len = event->size
+    };
+
+    assert(event->id < network_filters_count);
+
+    qemu_netfilter_pass_to_next(network_filters[event->id]->netdev,
+        event->flags, &iov, 1, network_filters[event->id]);
+
+    g_free(event->data);
+    g_free(event);
+}
+
+void replay_event_net_save(void *opaque)
+{
+    NetEvent *event = opaque;
+
+    replay_put_byte(event->id);
+    replay_put_dword(event->flags);
+    replay_put_array(event->data, event->size);
+}
+
+void *replay_event_net_load(void)
+{
+    NetEvent *event = g_new(NetEvent, 1);
+
+    event->id = replay_get_byte();
+    event->flags = replay_get_dword();
+    replay_get_array_alloc(&event->data, &event->size);
+
+    return event;
+}
diff --git a/replay/replay.c b/replay/replay.c
index c797aea..7f27cf1 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -21,7 +21,7 @@
 
 /* Current version of the replay mechanism.
    Increase it when file format changes. */
-#define REPLAY_VERSION              0xe02004
+#define REPLAY_VERSION              0xe02005
 /* Size of replay log header */
 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))