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net: add tap_set_offload()

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This API allows virtio-net to enable various offload features on a
tap interface - e.g. to tell the host kernel it can pass up partial
checksums to userspace.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Mark McLoughlin 2009-10-22 17:43:46 +01:00 committed by Anthony Liguori
parent 3a330134b3
commit b1c28b464d
3 changed files with 32 additions and 0 deletions
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24
net.c
View File

@ -1302,6 +1302,9 @@ int tap_has_vnet_hdr(VLANClientState *vc)
void tap_using_vnet_hdr(VLANClientState *vc, int using_vnet_hdr)
{
}
void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, int ecn)
{
}
#else /* !defined(_WIN32) */
/* Maximum GSO packet size (64k) plus plenty of room for
@ -1539,6 +1542,27 @@ static int tap_probe_vnet_hdr(int fd)
return ifr.ifr_flags & IFF_VNET_HDR;
}
void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, int ecn)
{
TAPState *s = vc->opaque;
unsigned int offload = 0;
if (csum) {
offload |= TUN_F_CSUM;
if (tso4)
offload |= TUN_F_TSO4;
if (tso6)
offload |= TUN_F_TSO6;
if ((tso4 || tso6) && ecn)
offload |= TUN_F_TSO_ECN;
}
if (ioctl(s->fd, TUNSETOFFLOAD, offload) != 0) {
fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",
strerror(errno));
}
}
static void tap_cleanup(VLANClientState *vc)
{
TAPState *s = vc->opaque;

1
net.h
View File

@ -182,5 +182,6 @@ void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
int tap_has_vnet_hdr(VLANClientState *vc);
void tap_using_vnet_hdr(VLANClientState *vc, int using_vnet_hdr);
void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, int ecn);
#endif

7
tap-linux.h
View File

@ -22,6 +22,7 @@
/* Ioctl defines */
#define TUNSETIFF _IOW('T', 202, int)
#define TUNGETFEATURES _IOR('T', 207, unsigned int)
#define TUNSETOFFLOAD _IOW('T', 208, unsigned int)
#define TUNGETIFF _IOR('T', 210, unsigned int)
#define TUNSETSNDBUF _IOW('T', 212, int)
@ -30,6 +31,12 @@
#define IFF_NO_PI 0x1000
#define IFF_VNET_HDR 0x4000
/* Features for GSO (TUNSETOFFLOAD). */
#define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */
#define TUN_F_TSO4 0x02 /* I can handle TSO for IPv4 packets */
#define TUN_F_TSO6 0x04 /* I can handle TSO for IPv6 packets */
#define TUN_F_TSO_ECN 0x08 /* I can handle TSO with ECN bits. */
struct virtio_net_hdr
{
uint8_t flags;