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Commit ed9ecb04 authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio: Don't expose legacy net features when VIRTIO_NET_NO_LEGACY defined. 



In particular, the virtio header always has the u16 num_buffers field.
We define a new 'struct virtio_net_hdr_v1' for this (rather than
simply calling it 'struct virtio_net_hdr', to avoid nasty type errors
if some parts of a project define VIRTIO_NET_NO_LEGACY and some don't.

Transitional devices (which can't define VIRTIO_NET_NO_LEGACY) will
have to keep using struct virtio_net_hdr_mrg_rxbuf, which has the same
byte layout as struct virtio_net_hdr_v1.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 1e1c17a7

include/uapi/linux/virtio_net.h

+30 −2
Original line number Diff line number Diff line
@@ -35,7 +35,6 @@ 
#define VIRTIO_NET_F_CSUM	0	/* Host handles pkts w/ partial csum */

#define VIRTIO_NET_F_GUEST_CSUM	1	/* Guest handles pkts w/ partial csum */

#define VIRTIO_NET_F_MAC	5	/* Host has given MAC address. */

#define VIRTIO_NET_F_GSO	6	/* Host handles pkts w/ any GSO type */

#define VIRTIO_NET_F_GUEST_TSO4	7	/* Guest can handle TSOv4 in. */

#define VIRTIO_NET_F_GUEST_TSO6	8	/* Guest can handle TSOv6 in. */

#define VIRTIO_NET_F_GUEST_ECN	9	/* Guest can handle TSO[6] w/ ECN in. */
@@ -56,6 +55,10 @@ 
					 * Steering */

#define VIRTIO_NET_F_CTRL_MAC_ADDR 23	/* Set MAC address */



#ifndef VIRTIO_NET_NO_LEGACY

#define VIRTIO_NET_F_GSO	6	/* Host handles pkts w/ any GSO type */

#endif /* VIRTIO_NET_NO_LEGACY */



#define VIRTIO_NET_S_LINK_UP	1	/* Link is up */

#define VIRTIO_NET_S_ANNOUNCE	2	/* Announcement is needed */
@@ -71,8 +74,9 @@ struct virtio_net_config { 
	__u16 max_virtqueue_pairs;

} __attribute__((packed));



#ifndef VIRTIO_NET_NO_LEGACY

/* This header comes first in the scatter-gather list.

 * If VIRTIO_F_ANY_LAYOUT is not negotiated, it must

 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must

 * be the first element of the scatter-gather list.  If you don't

 * specify GSO or CSUM features, you can simply ignore the header. */

struct virtio_net_hdr {
@@ -97,6 +101,30 @@ struct virtio_net_hdr_mrg_rxbuf { 
	struct virtio_net_hdr hdr;

	__virtio16 num_buffers;	/* Number of merged rx buffers */

};

#else /* ... VIRTIO_NET_NO_LEGACY */

/*

 * This header comes first in the scatter-gather list.  If you don't

 * specify GSO or CSUM features, you can simply ignore the header.

 *

 * This is bitwise-equivalent to the legacy struct virtio_net_hdr_mrg_rxbuf.

 */

struct virtio_net_hdr_v1 {

#define VIRTIO_NET_HDR_F_NEEDS_CSUM	1	/* Use csum_start, csum_offset */

#define VIRTIO_NET_HDR_F_DATA_VALID	2	/* Csum is valid */

	__u8 flags;

#define VIRTIO_NET_HDR_GSO_NONE		0	/* Not a GSO frame */

#define VIRTIO_NET_HDR_GSO_TCPV4	1	/* GSO frame, IPv4 TCP (TSO) */

#define VIRTIO_NET_HDR_GSO_UDP		3	/* GSO frame, IPv4 UDP (UFO) */

#define VIRTIO_NET_HDR_GSO_TCPV6	4	/* GSO frame, IPv6 TCP */

#define VIRTIO_NET_HDR_GSO_ECN		0x80	/* TCP has ECN set */

	__u8 gso_type;

	__virtio16 hdr_len;	/* Ethernet + IP + tcp/udp hdrs */

	__virtio16 gso_size;	/* Bytes to append to hdr_len per frame */

	__virtio16 csum_start;	/* Position to start checksumming from */

	__virtio16 csum_offset;	/* Offset after that to place checksum */

	__virtio16 num_buffers;	/* Number of merged rx buffers */

};

#endif /* ...VIRTIO_NET_NO_LEGACY */



/*

 * Control virtqueue data structures