[PATCH v3 7/8] qemu:virtio-net: Add additional MACs via a filter table

Alex Williamson
2009-02-05T00:21:23Z

Create a filter table and allow the guest to populate it with the
MAC class control commands. We manage the size and usage of the
filter table including enabling promiscuous and all-multi modes
as necessary. The guest should therefore assume the table is
infinite. Eventually this might allow us to bind directly to a
hardware NIC and manipulate a physical MAC filter.

The specifics of the TABLE_SET command are documented in
virtio-net.h. Separate buffers in the same command are used
for unicaste and multicast addresses for priority and
sychronization. With this we can export the VIRTIO_NET_F_CTRL_RX
feature bit.

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

hw/virtio-net.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
hw/virtio-net.h | 22 ++++++++++++++
2 files changed, 109 insertions(+), 2 deletions(-)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 001169d..524ef37 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -16,7 +16,9 @@
#include "qemu-timer.h"
#include "virtio-net.h"

-#define VIRTIO_NET_VM_VERSION 4
+#define VIRTIO_NET_VM_VERSION 5
+
+#define MAC_TABLE_ENTRIES 32

typedef struct VirtIONet
{
@@ -32,6 +34,10 @@ typedef struct VirtIONet
int mergeable_rx_bufs;
int promisc;
int allmulti;
+ struct {
+ int in_use;
+ uint8_t *macs;
+ } mac_table;
} VirtIONet;

/* TODO
@@ -87,13 +93,18 @@ static void virtio_net_reset(VirtIODevice *vdev)
/* Reset back to compatibility mode */
n->promisc = 1;
n->allmulti = 0;
+
+ /* Flush any MAC filter table state */
+ n->mac_table.in_use = 0;
+ memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
}

static uint32_t virtio_net_get_features(VirtIODevice *vdev)
{
uint32_t features = (1 << VIRTIO_NET_F_MAC) |
(1 << VIRTIO_NET_F_STATUS) |
- (1 << VIRTIO_NET_F_CTRL_VQ);
+ (1 << VIRTIO_NET_F_CTRL_VQ) |
+ (1 << VIRTIO_NET_F_CTRL_RX);

return features;
}
@@ -127,6 +138,53 @@ static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd,
return VIRTIO_NET_OK;
}

+static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
+ VirtQueueElement *elem)
+{
+ struct virtio_net_ctrl_mac mac_data;
+
+ if (cmd != VIRTIO_NET_CTRL_MAC_TABLE_SET || elem->out_num != 3 ||
+ elem->out_sg[1].iov_len < sizeof(mac_data) ||
+ elem->out_sg[2].iov_len < sizeof(mac_data))
+ return VIRTIO_NET_ERR;
+
+ n->mac_table.in_use = 0;
+ memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
+
+ mac_data.entries = ldl_le_p(elem->out_sg[1].iov_base);
+
+ if (sizeof(mac_data.entries) +
+ (mac_data.entries * ETH_ALEN) > elem->out_sg[1].iov_len)
+ return VIRTIO_NET_ERR;
+
+ if (mac_data.entries <= MAC_TABLE_ENTRIES) {
+ memcpy(n->mac_table.macs, elem->out_sg[1].iov_base + sizeof(mac_data),
+ mac_data.entries * ETH_ALEN);
+ n->mac_table.in_use += mac_data.entries;
+ } else {
+ n->promisc = 1;
+ return VIRTIO_NET_OK;
+ }
+
+ mac_data.entries = ldl_le_p(elem->out_sg[2].iov_base);
+
+ if (sizeof(mac_data.entries) +
+ (mac_data.entries * ETH_ALEN) > elem->out_sg[2].iov_len)
+ return VIRTIO_NET_ERR;
+
+ if (mac_data.entries) {
+ if (n->mac_table.in_use + mac_data.entries <= MAC_TABLE_ENTRIES) {
+ memcpy(n->mac_table.macs + (n->mac_table.in_use * ETH_ALEN),
+ elem->out_sg[2].iov_base + sizeof(mac_data),
+ mac_data.entries * ETH_ALEN);
+ n->mac_table.in_use += mac_data.entries;
+ } else
+ n->allmulti = 1;
+ }
+
+ return VIRTIO_NET_OK;
+}
+
static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
@@ -151,6 +209,8 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)

if (ctrl.class == VIRTIO_NET_CTRL_RX_MODE)
status = virtio_net_handle_rx_mode(n, ctrl.cmd, &elem);
+ else if (ctrl.class == VIRTIO_NET_CTRL_MAC)
+ status = virtio_net_handle_mac(n, ctrl.cmd, &elem);

stb_p(elem.in_sg[elem.in_num - 1].iov_base, status);

@@ -226,6 +286,7 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
{
static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
uint8_t *ptr = (uint8_t *)buf;
+ int i;

if (n->promisc)
return 1;
@@ -244,6 +305,11 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
if (!memcmp(ptr, n->mac, ETH_ALEN))
return 1;

+ for (i = 0; i < n->mac_table.in_use; i++) {
+ if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN))
+ return 1;
+ }
+
return 0;
}

@@ -406,6 +472,8 @@ static void virtio_net_save(QEMUFile *f, void *opaque)
qemu_put_be16(f, n->status);
qemu_put_be32(f, n->promisc);
qemu_put_be32(f, n->allmulti);
+ qemu_put_be32(f, n->mac_table.in_use);
+ qemu_put_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN);
}

static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
@@ -429,6 +497,19 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
n->allmulti = qemu_get_be32(f);
}

+ if (version_id >= 5) {
+ n->mac_table.in_use = qemu_get_be32(f);
+ /* MAC_TABLE_ENTRIES may be different from the saved image */
+ if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
+ qemu_get_buffer(f, n->mac_table.macs,
+ n->mac_table.in_use * ETH_ALEN);
+ } else if (n->mac_table.in_use) {
+ qemu_fseek(f, n->mac_table.in_use * ETH_ALEN, SEEK_CUR);
+ n->promisc = 1;
+ n->mac_table.in_use = 0;
+ }
+ }
+
if (n->tx_timer_active) {
qemu_mod_timer(n->tx_timer,
qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
@@ -474,6 +555,10 @@ void virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
n->mergeable_rx_bufs = 0;
n->promisc = 1; /* for compatibility */

+ n->mac_table.macs = qemu_mallocz(MAC_TABLE_ENTRIES * ETH_ALEN);
+ if (!n->mac_table.macs)
+ return;
+
register_savevm("virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,
virtio_net_save, virtio_net_load, n);
}
diff --git a/hw/virtio-net.h b/hw/virtio-net.h
index ce8e4b4..291fa9d 100644
--- a/hw/virtio-net.h
+++ b/hw/virtio-net.h
@@ -113,4 +113,26 @@ typedef uint8_t virtio_net_ctrl_ack;
#define VIRTIO_NET_CTRL_RX_MODE_PROMISC 0
#define VIRTIO_NET_CTRL_RX_MODE_ALLMULTI 1

+/*
+ * Control the MAC filter table.
+ *
+ * The MAC filter table is managed by the hypervisor, the guest should
+ * assume the size is infinite. Filtering should be considered
+ * non-perfect, ie. based on hypervisor resources, the guest may
+ * received packets from sources not specified in the filter list.
+ *
+ * In addition to the class/cmd header, the TABLE_SET command requires
+ * two out scatterlists. Each contains a 4 byte count of entries followed
+ * by a concatenated byte stream of the ETH_ALEN MAC addresses. The
+ * first sg list contains unicast addresses, the second is for multicast.
+ * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
+ * is available.
+ */
+struct virtio_net_ctrl_mac {
+ uint32_t entries;
+ uint8_t macs[][ETH_ALEN];
+};
+#define VIRTIO_NET_CTRL_MAC 1
+ #define VIRTIO_NET_CTRL_MAC_TABLE_SET 0
+
#endif