[PATCH v3 8/8] qemu:virtio-net: Add VLAN filtering

Alex Williamson
2009-02-05T00:21:27Z

Use the control virtqueue to allow the guest to enable and manipulate
a VLAN filter table. This allows us to drop more packets the guest
doesn't want to see. We define a new VLAN class for the control
virtqueue with commands ADD and DEL with usage defined in virtio-net.h.

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

hw/virtio-net.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
hw/virtio-net.h | 14 ++++++++++++++
2 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 524ef37..62153e9 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -16,9 +16,10 @@
#include "qemu-timer.h"
#include "virtio-net.h"

-#define VIRTIO_NET_VM_VERSION 5
+#define VIRTIO_NET_VM_VERSION 6

#define MAC_TABLE_ENTRIES 32
+#define MAX_VLAN (1 << 12) /* Per 802.1Q definition */

typedef struct VirtIONet
{
@@ -38,6 +39,7 @@ typedef struct VirtIONet
int in_use;
uint8_t *macs;
} mac_table;
+ uint32_t *vlans;
} VirtIONet;

/* TODO
@@ -94,9 +96,10 @@ static void virtio_net_reset(VirtIODevice *vdev)
n->promisc = 1;
n->allmulti = 0;

- /* Flush any MAC filter table state */
+ /* Flush any MAC and VLAN filter table state */
n->mac_table.in_use = 0;
memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
+ memset(n->vlans, 0, MAX_VLAN >> 3);
}

static uint32_t virtio_net_get_features(VirtIODevice *vdev)
@@ -104,7 +107,8 @@ 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_RX);
+ (1 << VIRTIO_NET_F_CTRL_RX) |
+ (1 << VIRTIO_NET_F_CTRL_VLAN);

return features;
}
@@ -185,6 +189,31 @@ static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
return VIRTIO_NET_OK;
}

+static int virtio_net_handle_vlan_table(VirtIONet *n, uint8_t cmd,
+ VirtQueueElement *elem)
+{
+ uint16_t vid;
+
+ if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(vid)) {
+ fprintf(stderr, "virtio-net ctrl invalid vlan command\n");
+ return VIRTIO_NET_ERR;
+ }
+
+ vid = lduw_le_p(elem->out_sg[1].iov_base);
+
+ if (vid >= MAX_VLAN)
+ return VIRTIO_NET_ERR;
+
+ if (cmd == VIRTIO_NET_CTRL_VLAN_ADD)
+ n->vlans[vid >> 5] |= (1U << (vid & 0x1f));
+ else if (cmd == VIRTIO_NET_CTRL_VLAN_DEL)
+ n->vlans[vid >> 5] &= ~(1U << (vid & 0x1f));
+ 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);
@@ -211,6 +240,8 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
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);
+ else if (ctrl.class == VIRTIO_NET_CTRL_VLAN)
+ status = virtio_net_handle_vlan_table(n, ctrl.cmd, &elem);

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

@@ -285,6 +316,7 @@ static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
{
static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+ static const uint8_t vlan[] = {0x81, 0x00};
uint8_t *ptr = (uint8_t *)buf;
int i;

@@ -296,6 +328,12 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
ptr += sizeof(struct virtio_net_hdr);
#endif

+ if (!memcmp(&ptr[12], vlan, sizeof(vlan))) {
+ int vid = be16_to_cpup((uint16_t *)(ptr + 14)) & 0xfff;
+ if (!(n->vlans[vid >> 5] & (1U << (vid & 0x1f))))
+ return 0;
+ }
+
if ((ptr[0] & 1) && n->allmulti)
return 1;

@@ -474,6 +512,7 @@ static void virtio_net_save(QEMUFile *f, void *opaque)
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);
+ qemu_put_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
}

static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
@@ -510,6 +549,9 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
}
}

+ if (version_id >= 6)
+ qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
+
if (n->tx_timer_active) {
qemu_mod_timer(n->tx_timer,
qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
@@ -559,6 +601,10 @@ void virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
if (!n->mac_table.macs)
return;

+ n->vlans = qemu_mallocz(MAX_VLAN >> 3);
+ if (!n->vlans)
+ 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 291fa9d..95587f7 100644
--- a/hw/virtio-net.h
+++ b/hw/virtio-net.h
@@ -42,6 +42,7 @@
#define VIRTIO_NET_F_STATUS 16 /* virtio_net_config.status available */
#define VIRTIO_NET_F_CTRL_VQ 17 /* Control channel available */
#define VIRTIO_NET_F_CTRL_RX 18 /* Control channel RX mode support */
+#define VIRTIO_NET_F_CTRL_VLAN 19 /* Control channel VLAN filtering */

#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */

@@ -135,4 +136,17 @@ struct virtio_net_ctrl_mac {
#define VIRTIO_NET_CTRL_MAC 1
#define VIRTIO_NET_CTRL_MAC_TABLE_SET 0

+/*
+ * Control VLAN filtering
+ *
+ * The VLAN filter table is controlled via a simple ADD/DEL interface.
+ * VLAN IDs not added may be filterd by the hypervisor. Del is the
+ * opposite of add. Both commands expect an out entry containing a 2
+ * byte VLAN ID. VLAN filterting is available with the
+ * VIRTIO_NET_F_CTRL_VLAN feature bit.
+ */
+#define VIRTIO_NET_CTRL_VLAN 2
+ #define VIRTIO_NET_CTRL_VLAN_ADD 0
+ #define VIRTIO_NET_CTRL_VLAN_DEL 1
+
#endif