[PATCH] clarify net mac commands.

Noticed this was underspecified (and unclear) while creating a patch to deprecate writable field{mac}.  Signed-off-by: Rusty Russell <>  diff --git a/content.tex b/content.tex index 01ecd1e..4171eff 100644 --- a/content.tex +++ b/content.tex @@ -3340,7 +3340,7 @@ many addresses.  } This table is set using the class  VIRTIO_NET_CTRL_MAC and the command VIRTIO_NET_CTRL_MAC_TABLE_SET. The  command-specific-data is two variable length tables of 6-byte MAC -addresses. The first table contains unicast addresses, and the second +addresses (as described in struct virtio_net_ctrl_mac). The first table contains unicast addresses, and the second  contains multicast addresses.
The VIRTIO_NET_CTRL_MAC_ADDR_SET command is used to set the @@ -3354,6 +3354,21 @@ accepts.  The command-specific-data for VIRTIO_NET_CTRL_MAC_ADDR_SET is  the 6-byte MAC address.
+devicenormative{subparagraph}{Setting MAC Address Filtering}{Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering} + +The device MUST have an empty MAC filtering table on reset. + +The device MUST update the MAC filtering table before it consumes +the VIRTIO_NET_CTRL_MAC_TABLE_SET command. + +The device MUST update field{mac} in config space before it consumes +the VIRTIO_NET_CTRL_MAC_ADDR_SET command, if VIRTIO_NET_F_MAC_ADDR has +been negotiated. + +The device SHOULD drop incoming packets which have a destination MAC which +matches neither the field{mac} (or that set with VIRTIO_NET_CTRL_MAC_ADDR_SET) +nor the MAC filtering table. +  drivernormative{subparagraph}{Setting MAC Address Filtering}{Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering}
A driver MUST NOT write to the field{mac} if VIRTIO_NET_F_MAC_ADDR is @@ -3365,6 +3380,11 @@ VIRTIO_NET_CTRL_MAC_ADDR_SET command is atomic whereas  MUST negotiate VIRTIO_NET_F_MAC_ADDR if they change  mac address when device is accepting incoming packets.
+The driver MUST follow the VIRTIO_NET_CTRL_MAC_TABLE_SET command +by a le32 number, followed by that number of non-multicast +MAC addresses, followed by another le32 number, followed by +that number of multicast addresses.  Either number MAY be 0. +  subparagraph{Legacy Interface: Setting MAC Address Filtering}label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering / Legacy Interface: Setting MAC Address Filtering}  When using the legacy interface, transitional devices and drivers  MUST format field{entries} in struct virtio_net_ctrl_mac