[PATCH 4/7] qemu:virtio-net: Add promiscuous and all-multicast mode bits

[Alex Williamson <alex.williamson@hp.com>]

Add a new RX_MODE control virtqueue class with commands PROMISC and
ALLMULTI and usage documented in virtio-net.h allowing the guest to
manipulate packet receiving options.

Note, for compatibility with older guest drivers we need to default
to promiscuous.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
---

 qemu/hw/virtio-net.c |   38 +++++++++++++++++++++++++++++++++++++-
 qemu/hw/virtio-net.h |    9 +++++++++
 2 files changed, 46 insertions(+), 1 deletions(-)

diff --git a/qemu/hw/virtio-net.c b/qemu/hw/virtio-net.c
index 3d8cba7..d34c299 100644
--- a/qemu/hw/virtio-net.c
+++ b/qemu/hw/virtio-net.c
@@ -21,7 +21,7 @@
 
 #define TAP_VNET_HDR
 
-#define VIRTIO_NET_VM_VERSION    3
+#define VIRTIO_NET_VM_VERSION    4
 
 #define ETH_ALEN    6
 
@@ -37,6 +37,8 @@ typedef struct VirtIONet
     QEMUTimer *tx_timer;
     int tx_timer_active;
     int mergeable_rx_bufs;
+    int promisc;
+    int allmulti;
 } VirtIONet;
 
 /* TODO
@@ -131,8 +133,31 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
 #endif
 }
 
+static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd,
+                                     VirtQueueElement *elem)
+{
+    uint8_t *on;
+
+    if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(*on)) {
+        fprintf(stderr, "virtio-net ctrl invalid rx mode command\n");
+        exit(1);
+    }
+
+    on = elem->out_sg[1].iov_base;
+
+    if (cmd == VIRTIO_NET_CTRL_RX_MODE_PROMISC)
+        n->promisc = *on;
+    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLMULTI)
+        n->allmulti = *on;
+    else
+        return VIRTIO_NET_ERR;
+
+    return VIRTIO_NET_OK;
+}
+
 static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 {
+    VirtIONet *n = to_virtio_net(vdev);
     struct virtio_net_ctrl_hdr *ctrl;
     virtio_net_ctrl_ack *status;
     VirtQueueElement elem;
@@ -153,6 +178,9 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
         status = elem.in_sg[elem.in_num - 1].iov_base;
         *status = VIRTIO_NET_ERR;
 
+        if (ctrl->class == VIRTIO_NET_CTRL_RX_MODE)
+            *status = virtio_net_handle_rx_mode(n, ctrl->cmd, &elem);
+
         virtqueue_push(vq, &elem, sizeof(*status));
         virtio_notify(vdev, vq);
     }
@@ -435,6 +463,8 @@ static void virtio_net_save(QEMUFile *f, void *opaque)
 #endif
 
     qemu_put_be16(f, n->status);
+    qemu_put_be32(f, n->promisc);
+    qemu_put_be32(f, n->allmulti);
 }
 
 static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
@@ -459,6 +489,11 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
 
     n->status = qemu_get_be16(f);
 
+    if (version_id >= 4) {
+        n->promisc = qemu_get_be32(f);
+        n->allmulti = qemu_get_be32(f);
+    }
+
     if (n->tx_timer_active) {
         qemu_mod_timer(n->tx_timer,
                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
@@ -498,6 +533,7 @@ PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
     n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);
     n->tx_timer_active = 0;
     n->mergeable_rx_bufs = 0;
+    n->promisc = 1; /* for compatibility */
 
     register_savevm("virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,
                     virtio_net_save, virtio_net_load, n);
diff --git a/qemu/hw/virtio-net.h b/qemu/hw/virtio-net.h
index 9a9641e..a4c4005 100644
--- a/qemu/hw/virtio-net.h
+++ b/qemu/hw/virtio-net.h
@@ -99,4 +99,13 @@ typedef uint8_t virtio_net_ctrl_ack;
 #define VIRTIO_NET_OK     0
 #define VIRTIO_NET_ERR    1
 
+/*
+ * Control the RX mode, ie. promisucous and allmulti.  PROMISC and
+ * ALLMULTI commands require an "out" sg entry containing a 1 byte
+ * state value, zero = disable, non-zero = enable.
+ */
+#define VIRTIO_NET_CTRL_RX_MODE    0
+ #define VIRTIO_NET_CTRL_RX_MODE_PROMISC      0
+ #define VIRTIO_NET_CTRL_RX_MODE_ALLMULTI     1
+
 #endif