Added new offloads for TUN devices TUN_F_USO4 and TUN_F_USO6. Technically they enable NETIF_F_GSO_UDP_L4 (and only if USO4 & USO6 are set simultaneously). It allows the transmission of large UDP packets. UDP Segmentation Offload (USO/GSO_UDP_L4) - ability to split UDP packets into several segments. It's similar to UFO, except it doesn't use IP fragmentation. The drivers may push big packets and the NIC will split them(or assemble them in case of receive), but in the case of VirtioNet we just pass big UDP to the host. So we are freeing the driver from doing the unnecessary job of splitting. The same thing for several guests on one host, we can pass big packets between guests. Different features USO4 and USO6 are required for qemu where Windows guests can enable disable USO receives for IPv4 and IPv6 separately. On the other side, Linux can't really differentiate USO4 and USO6, for now. For now, to enable USO for TUN it requires enabling USO4 and USO6 together. In the future, there would be a mechanism to control UDP_L4 GSO separately. New types for virtio-net already in virtio-net specification: https://github.com/oasis-tcs/virtio-spec/issues/120 Test it WIP Qemu https://github.com/daynix/qemu/tree/USOv3 Changes since v4 & RFC: * Fixed typo and refactored. * Tun USO offload refactored. * Add support for guest-to-guest segmentation offload (thx Jason). Andrew Melnychenko (6): udp: allow header check for dodgy GSO_UDP_L4 packets. uapi/linux/if_tun.h: Added new offload types for USO4/6. driver/net/tun: Added features for USO. uapi/linux/virtio_net.h: Added USO types. linux/virtio_net.h: Support USO offload in vnet header. drivers/net/virtio_net.c: Added USO support. drivers/net/tap.c | 10 ++++++++-- drivers/net/tun.c | 8 +++++++- drivers/net/virtio_net.c | 19 +++++++++++++++---- include/linux/virtio_net.h | 9 +++++++++ include/uapi/linux/if_tun.h | 2 ++ include/uapi/linux/virtio_net.h | 4 ++++ net/ipv4/udp_offload.c | 3 ++- net/ipv6/udp_offload.c | 3 ++- 8 files changed, 49 insertions(+), 9 deletions(-) -- 2.38.1 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
