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  1. 04 5月, 2018 1 次提交
    • D
      nwfilter: remove pointless virNWFilterHashTable struct · 77646d94
      由 Daniel P. Berrangé 提交于 
      The virNWFilterHashTable struct only contains a single virHashTable
member since

  commit 293d4fe2
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Mon Mar 24 16:35:23 2014 +0000

    Remove pointless storage of var names in virNWFilterHashTable

Thus, this struct wrapper adds no real value over just using the
virHashTable directly, but brings the complexity of needing to derefence
the hashtable to call virHash* APIs, and adds extra memory allocation
step.

To minimize code churn this just turns virNWFilterHashTable into a
typedef aliases virHashTable.
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      77646d94
  3. 03 5月, 2018 13 次提交
  5. 02 5月, 2018 2 次提交
  7. 30 4月, 2018 5 次提交
  9. 28 4月, 2018 1 次提交
    • L
      nwfilter: increase pcap buffer size to be compatible with TPACKET_V3 · ce5aebea
      由 Laine Stump 提交于 
      When an nwfilter rule sets the parameter CTRL_IP_LEARNING to "dhcp",
this turns on the "dhcpsnoop" thread, which uses libpcap to monitor
traffic on the domain's tap device and extract the IP address from the
DHCP response.

If libpcap on the host is built with HAVE_TPACKET3 defined (to enable
support for TPACKET_V3), the dhcpsnoop code's initialization of the
libpcap socket would fail with the following error:

  virNWFilterSnoopDHCPOpen:1134 : internal error: pcap_setfilter: can't remove kernel filter: Bad file descriptor

It turns out that this was because TPACKET_V3 requires a larger buffer
size than libvirt was setting (we were setting it to 128k). Changing
the buffer size to 256k eliminates the error, and the dhcpsnoop thread
once again works properly.

A fuller explanation of why TPACKET_V3 requires such a large buffer,
for future git spelunkers:

libpcap calls setsockopt(... SOL_PACKET, PACKET_RX_RING...) to setup a
ring buffer for receiving packets; two of the attributes sent to this
API are called tp_frame_size, and tp_frame_nr. If libpcap was built
with HAVE_TPACKET3 defined, tp_trame_size is set to MAXIMUM_SNAPLEN
(defined in libpcap sources as 262144) and tp_frame_nr is set to:

 [the buffer size we set, i.e. PCAP_BUFFERSIZE i.e. 262144] / tp_frame_size.

So if PCAP_BUFFERSIZE < MAXIMUM_SNAPLEN, then tp_frame_nr (the number
of frames in the ring buffer) is 0, which is nonsensical. This same
value is later used as a multiplier to determine the size for a call
to malloc() (which would also fail).

(NB: if HAVE_TPACKET3 is *not* defined, then tp_frame_size is set to
the snaplen set by the user (in our case 576) plus a small amount to
account for ethernet headers, so 256k is far more than adequate)

Since the TPACKET_V3 code in libpcap actually reads multiple packets
into each frame, it's not a problem to have only a single frame
(especially when we are monitoring such infrequent traffic), so it's
okay to set this relatively small buffer size (in comparison to the
default, which is 2MB), which is important since every guest using
dhcp snooping in a nwfilter rule will hold 2 of these buffers for the
entire life of the guest.

Thanks to Christian Ehrhardt for discovering that buffer size was the
problem (this was not at all obvious from the error that was logged!)

Resolves: https://bugzilla.redhat.com/1547237
Fixes: https://bugs.launchpad.net/libvirt/+bug/1758037Signed-off-by: NLaine Stump <laine@laine.org>
Reviewed-by: Christian Ehrhardt <christian.ehrhardt@canonical.com> (V1)
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Tested-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>
      ce5aebea
  11. 27 4月, 2018 3 次提交
  13. 26 4月, 2018 2 次提交
  15. 25 4月, 2018 10 次提交
  17. 24 4月, 2018 3 次提交
    • D
      build: prevent unloading of dlopen'd modules · 71feef92
      由 Daniel P. Berrangé 提交于 
      We previously added "-z nodelete" to the build of libvirt.so to prevent
crashes when thread local destructors run which point to a code that
has been dlclose()d:

  commit 8e44e559
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Thu Sep 1 17:57:06 2011 +0100

      Prevent crash from dlclose() of libvirt.so

The libvirtd loadable modules can suffer from the same problem if they
were ever unloaded. Fortunately we don't ever call dlclose() on them,
but lets add a second layer of protection by linking them with the
"-z nodelete" flag. While we're doing this, lets add a third layer of
protection by passing RTLD_NODELETE to dlopen().
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      71feef92
    • D
      remote: stop trying to load Xen driver module · 87680332
      由 Daniel P. Berrangé 提交于 
      The Xen driver was recently deleted, but libvirtd has left over code
that tries to use it. Fortunately this is dead code because WITH_XEN
will never be defined anymore.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      87680332
    • D
      build: prevent unloading of all public libraries · 419607c4
      由 Daniel P. Berrangé 提交于 
      We previously added "-z nodelete" to the build of libvirt.so to prevent
crashes when thread local destructors run which point to a code that
has been dlclose()d:

  commit 8e44e559
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Thu Sep 1 17:57:06 2011 +0100

      Prevent crash from dlclose() of libvirt.so

We forgot to copy this protection into the libvirt-qemu.so, libvirt-lxc.so
and libvirt-admin.so libraries when we introduced them.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      419607c4