[Qemu-devel] [PATCH 4/5] net/dump: Add dump option for netdev devices

[Thomas Huth <thuth@redhat.com>]

So far it is not possible to dump network traffic with the "-netdev"
option yet - this is only possible with the "-net" option and an
internal "hub".
This patch now fixes this ugliness by adding a proper, generic
dumpfile parameter to the "-netdev" option.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 include/net/net.h |  1 +
 net/net.c         | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json  | 12 ++++++++++--
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index b265047..62abc98 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -98,6 +98,7 @@ struct NetClientState {
     NetClientDestructor *destructor;
     unsigned int queue_index;
     unsigned rxfilter_notify_enabled:1;
+    unsigned netdev_dump_enabled:1;
     NetDumpState nds;
 };
 
diff --git a/net/net.c b/net/net.c
index cc36c7b..8871b77 100644
--- a/net/net.c
+++ b/net/net.c
@@ -568,6 +568,12 @@ ssize_t qemu_deliver_packet(NetClientState *sender,
         return 0;
     }
 
+    if (nc->netdev_dump_enabled) {
+        net_dump_receive(nc, data, size);
+    } else if (sender->netdev_dump_enabled) {
+        net_dump_receive(sender, data, size);
+    }
+
     if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
         ret = nc->info->receive_raw(nc, data, size);
     } else {
@@ -684,6 +690,12 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender,
         return 0;
     }
 
+    if (nc->netdev_dump_enabled) {
+        net_dump_receive_iov(nc, iov, iovcnt);
+    } else if (sender->netdev_dump_enabled) {
+        net_dump_receive_iov(sender, iov, iovcnt);
+    }
+
     if (nc->info->receive_iov) {
         ret = nc->info->receive_iov(nc, iov, iovcnt);
     } else {
@@ -877,6 +889,36 @@ static int net_init_nic(const NetClientOptions *opts, const char *name,
     return idx;
 }
 
+static int netdev_init_dumpfile(const Netdev *netdev, const char *name,
+                                Error **errp)
+{
+    NetClientState *nc;
+    int dumplen = 65536;
+    int rc;
+
+    if (netdev->opts->kind == NET_CLIENT_OPTIONS_KIND_TAP
+        && netdev->opts->tap->has_vhost && netdev->opts->tap->vhost) {
+        error_setg(errp, "dumping does not work with vhost enabled");
+        return -1;
+    }
+
+    if (netdev->has_dumplen) {
+        dumplen = netdev->dumplen;
+    }
+
+    nc = qemu_find_netdev(name);
+    if (!nc) {
+        error_setg(errp, "failed to lookup netdev for dump");
+        return -1;
+    }
+
+    rc = net_dump_state_init(nc, netdev->dumpfile, dumplen, errp);
+    if (rc == 0) {
+        nc->netdev_dump_enabled = true;
+    }
+
+    return rc;
+}
 
 static int (* const net_client_init_fun[NET_CLIENT_OPTIONS_KIND_MAX])(
     const NetClientOptions *opts,
@@ -982,6 +1024,12 @@ static int net_client_init1(const void *object, int is_netdev, Error **errp)
             }
             return -1;
         }
+
+        if (is_netdev && u.netdev->has_dumpfile) {
+            if (netdev_init_dumpfile(u.netdev, name, errp)) {
+                return -1;
+            }
+        }
     }
     return 0;
 }
diff --git a/qapi-schema.json b/qapi-schema.json
index 106008c..79c3ed7 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2528,14 +2528,22 @@
 #
 # @id: identifier for monitor commands.
 #
+# @dumpfile: #optional name of a file where network traffic should be logged
+#            (since: 2.4)
+#
+# @dumplen: #optional maximum length of the network packets in the dump
+#           (since: 2.4)
+#
 # @opts: device type specific properties
 #
 # Since 1.2
 ##
 { 'struct': 'Netdev',
   'data': {
-    'id':   'str',
-    'opts': 'NetClientOptions' } }
+    'id':        'str',
+    '*dumpfile': 'str',
+    '*dumplen':  'int32',
+    'opts':      'NetClientOptions' } }
 
 ##
 # @InetSocketAddress
-- 
1.8.3.1