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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.

Rusty Russell committed 11 years ago

Commit ed9ecb01 parent 1e1c17a1 file · +30 −2Browse files

Showing the changes to include/uapi/linux (1 of 1 file). Show all

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include/uapi/linux/virtio_net.h+30−2
@@ -35,7 +35,6 @@ · 34 unmodified lines
35#define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */35#define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */
36#define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */36#define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */
37#define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */37#define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */
38#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
39#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */38#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
40#define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */39#define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */
41#define VIRTIO_NET_F_GUEST_ECN 9 /* Guest can handle TSO[6] w/ ECN in. */40#define VIRTIO_NET_F_GUEST_ECN 9 /* Guest can handle TSO[6] w/ ECN in. */
@@ -56,6 +55,10 @@ · 14 unmodified lines
56 * Steering */55 * Steering */
57#define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */56#define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
58 57
58#ifndef VIRTIO_NET_NO_LEGACY
59#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
60#endif /* VIRTIO_NET_NO_LEGACY */
61
59#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */62#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
60#define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */63#define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */
61 64
@@ -71,8 +74,9 @@ struct virtio_net_config { · 9 unmodified lines
71 __u16 max_virtqueue_pairs;74 __u16 max_virtqueue_pairs;
72} __attribute__((packed));75} __attribute__((packed));
73 76
77#ifndef VIRTIO_NET_NO_LEGACY
74/* This header comes first in the scatter-gather list.78/* This header comes first in the scatter-gather list.
75 * If VIRTIO_F_ANY_LAYOUT is not negotiated, it must79 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must
76 * be the first element of the scatter-gather list. If you don't80 * be the first element of the scatter-gather list. If you don't
77 * specify GSO or CSUM features, you can simply ignore the header. */81 * specify GSO or CSUM features, you can simply ignore the header. */
78struct virtio_net_hdr {82struct virtio_net_hdr {
@@ -97,6 +101,30 @@ struct virtio_net_hdr_mrg_rxbuf { · 18 unmodified lines
97 struct virtio_net_hdr hdr;101 struct virtio_net_hdr hdr;
98 __virtio16 num_buffers; /* Number of merged rx buffers */102 __virtio16 num_buffers; /* Number of merged rx buffers */
99};103};
104#else /* ... VIRTIO_NET_NO_LEGACY */
105/*
106 * This header comes first in the scatter-gather list. If you don't
107 * specify GSO or CSUM features, you can simply ignore the header.
108 *
109 * This is bitwise-equivalent to the legacy struct virtio_net_hdr_mrg_rxbuf.
110 */
111struct virtio_net_hdr_v1 {
112#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */
113#define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */
114 __u8 flags;
115#define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */
116#define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */
117#define VIRTIO_NET_HDR_GSO_UDP 3 /* GSO frame, IPv4 UDP (UFO) */
118#define VIRTIO_NET_HDR_GSO_TCPV6 4 /* GSO frame, IPv6 TCP */
119#define VIRTIO_NET_HDR_GSO_ECN 0x80 /* TCP has ECN set */
120 __u8 gso_type;
121 __virtio16 hdr_len; /* Ethernet + IP + tcp/udp hdrs */
122 __virtio16 gso_size; /* Bytes to append to hdr_len per frame */
123 __virtio16 csum_start; /* Position to start checksumming from */
124 __virtio16 csum_offset; /* Offset after that to place checksum */
125 __virtio16 num_buffers; /* Number of merged rx buffers */
126};
127#endif /* ...VIRTIO_NET_NO_LEGACY */
100 128
101/*129/*
102 * Control virtqueue data structures130 * Control virtqueue data structures