IFF_VNET_HDR is a tun/tap flag that allows you to send and receive
large (i.e. GSO) packets and packets with partial checksums. Setting
the flag means that every packet is proceeded by the same header which
virtio uses to communicate GSO/csum metadata.
By enabling this flag on the tap fds we create, we greatly increase
the achievable throughput with virtio_net.
However, we need to be careful to only set the flag when a) QEMU has
support for this ABI and b) the value of the flag is queryable using
the TUNGETIFF ioctl.
It's nearly five months since kvm-74 - the first KVM release with this
feature - was released. Up until now, we've not added libvirt support
because there is no clean way to detect support for this in QEMU at
runtime. A brief attempt to add a "info capabilities" monitor command
to QEMU floundered. Perfect is the enemy of good enough. Probing the
KVM version will suffice for now.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
* configure.in: Provide a new --with-bridge option.
* src/Makefile.am (PRIVSYMFILES) [WITH_BRIDGE]: Append libvirt_bridge.syms.
* src/bridge.c: Test WITH_BRIDGE rather than particular drivers.
* src/libvirt_private.syms: Move bridge-related symbols into...
* src/libvirt_bridge.syms: ...this new file.
Author: John Levon
Given code like: T *var = calloc (n, sizeof (T));
Convert to this: T *var = calloc (n, sizeof (*var));
This first-cut change adjusts all malloc, calloc, and
realloc statements.
The only binary differences are in remote_internal.c
(due to the bug fix) and in xmlrpc.c (due to factorization).
* python/libvir.c: As above.
* qemud/event.c: Likewise.
* qemud/mdns.c: Likewise.
* qemud/qemud.c: Likewise.
* qemud/remote.c: Likewise.
* src/bridge.c: Likewise.
* src/buf.c: Likewise.
* src/conf.c: Likewise.
* src/hash.c: Likewise.
* src/iptables.c: Likewise.
* src/openvz_conf.c: Likewise.
* src/qemu_conf.c: Likewise.
* src/qemu_driver.c: Likewise.
* src/test.c: Likewise.
* src/xen_internal.c: Likewise.
* src/xen_unified.c: Likewise.
* src/xm_internal.c: Likewise.
* src/xml.c: Likewise.
* tests/qemuxml2argvtest.c: Likewise.
* src/xmlrpc.c (xmlRpcValuePtr): Likewise, and minor factorization.
* src/remote_internal.c (remoteAuthMakeCredentials): Use the right
type when allocating space for an array of cred _pointers_.
* src/bridge.c, src/bridge.h, src/qemu_conf.c, src/qemu_conf.h,
src/qemu_driver.c, src/qemu_driver.h, src/test.c: Disable more
of qemu if configured --without-qemu.
* src/bridge.c, src/qemu_driver.c, configure.in: Try to detect
the paths of dnsmasq and brctl at compile time. If found
then compile them in, otherwise search $PATH at runtime.
* libvirt.spec.in: BR dnsmasq and bridge-utils so we have their
paths at compile time.
* acinclude.m4, configure.in: ./configure option
--disable-stack-protector.
* src/gnutls_1_0_compat.h: Compatibility with GnuTLS 1.0.
* src/bridge.c: If no bridge ioctls, give an error at runtime.
