Now that the nwfilter driver keeps a list of bindings that it has
created, there is no need for the complex virt driver callbacks. It is
possible to simply iterate of the list of recorded filter bindings.
This means that rebuilding filters no longer has to acquire any locks on
the virDomainObj objects, as they're never touched.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Currently the nwfilter driver does not keep any record of what filter
bindings it has active. This means that when it needs to recreate
filters, it has to rely on triggering callbacks provided by the virt
drivers. This introduces a hash table recording the virNWFilterBinding
objects so the driver has a record of all active filters.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Use the virNWFilterBindingDefPtr struct in the DHCP address snooping code
directly.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Use the virNWFilterBindingDefPTr struct in the IP address learning code
directly.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Use the virNWFilterBindingDefPtr struct in the gentech driver code
directly.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The compilation fails with the following error when pcap-config
is not present on the host:
nwfilter/nwfilter_learnipaddr.c:824:1: error: conflicting types for 'virNWFilterLearnIPAddress'
virNWFilterLearnIPAddress(virNWFilterTechDriverPtr techdriver ATTRIBUTE_UNUSED,
In file included from nwfilter/nwfilter_learnipaddr.c:57:0:
nwfilter/nwfilter_learnipaddr.h:38:5: note: previous declaration of 'virNWFilterLearnIPAddress' was here
int virNWFilterLearnIPAddress(virNWFilterTechDriverPtr techdriver,
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
When a QEMU VM shuts down its TAP device gets deleted while nwfilter
IP address learning thread is still capturing packets. It is seen that
with TPACKET_V3 support in libcap, the pcap_next() call will not always
exit its poll() when the NIC is removed. This prevents the learning
thread from exiting which blocks the rest of libvirtd waiting on mutex
acquisition. By switching to do poll() in libvirt code, we can ensure
that we always exit the poll() at a time that is right for libvirt.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
In a previous commit:
commit d4bf8f4150
Author: Daniel P. Berrangé <berrange@redhat.com>
Date: Wed Feb 14 09:43:59 2018 +0000
nwfilter: handle missing switch enum cases
Ensure all enum cases are listed in switch statements, or cast away
enum type in places where we don't wish to cover all cases.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
we changed a switch in the nwfilter learning thread so that it had
explict cases for all enum entries. Unfortunately the parameters in the
method had been declared with incorrect type. The "howDetect" parameter
does *not* accept "enum howDetect" values, rather it accepts a bitmask
of "enum howDetect" values, so it should have been an "int" type.
The caller always passes DETECT_STATIC|DETECT_DHCP, so essentially the
IP addressing learning was completely broken by the above change, as it
never matched any switch case, hitting the default leading to EINVAL.
Stop using a typedef for the parameter name this this is a bitmask,
not a plain enum value. Also stop using switch() since that's misleading
with bitmasks too.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The vm name is not needed for any functional requirement, but it will be
useful when debugging problems to identify which VM is associated with a
filter, since UUID is not human friendly.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The filter parameters were not correctly free'd when an error hits while
adding to the hash table.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
There is a bunch of left over code in the nwfilter driver related to
monitoring firewalld over dbus, that is no longer used since the
conversion to use virFirewall APIs.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The virNWFilterIPAddrLearnReq type should only be used by the IP address
learning code, so can live in the implementation file instead of header
file.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Various methods return a virNWFilterIPAddrLearnReq struct, but the
callers are only interested in whether the return value is non-NULL.
It is thus preferrable to just return a bool.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
All the code now just uses the virHashTablePtr type directly.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This removes the virNWFilterHashTableFree, virNWFilterHashTablePut
and virNWFilterHashTableRemove methods, in favour of just calling
the virHash APIs directly.
The virNWFilterHashTablePut method was unreasonably complex because
the virHashUpdateEntry already knows how to create the entry if it
does not currently exist.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The virNWFilterHashTable struct only contains a single virHashTable
member since
commit 293d4fe2f1
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: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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/1758037
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Christian Ehrhardt <christian.ehrhardt@canonical.com> (V1)
Reviewed-by: John Ferlan <jferlan@redhat.com>
Tested-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Ensuring that we don't call the virDrvConnectOpen method with a NULL URI
means that the drivers can drop various checks for NULL URIs. These were
not needed anymore since the probe functionality was split
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Declare what URI schemes a driver supports in its virConnectDriver
struct. This allows us to skip trying to open the driver entirely
if the URI scheme doesn't match.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Add a localOnly flag to the virConnectDriver struct which allows a
driver to indicate whether it is local-only, or permits remote
connections. Stateful drivers running inside libvirtd are generally
local only. This allows us to remote the check for uri->server != NULL
from most drivers.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
A problem encountered due to a bug in libpcap was reported to the
caller as:
An error occurred, but the cause is unknown
This was because the error had been logged in the DHCPSnoop
thread. The worker thread handling the API call to start a domain
spins up the DHCPSnoop thread which watches for dhcp packets with
libpcap, then uses virCondSignal() to notify the worker thread (which
has been waiting with virCondWait()). The worker thread knows that
there was an error (because threadStatus != THREAD_STATUS_OK), but the
error info had been stored in thread-specific storage for the other
thread, so the worker thread can only report that there was a failure,
but it doesn't know why.
The solution is to save the error that was logged (with
virErrorPreserveLast() into the object the is used to share info
between the threads, then we can set the error in the worker thread
using virErrorRestore().
In the case of the error I was looking at, this changed the "unknown"
message into:
internal error: pcap_setfilter: can't remove kernel filter:
Bad file descriptor
Signed-off-by: Laine Stump <laine@laine.org>
Ensure all enum cases are listed in switch statements, or cast away
enum type in places where we don't wish to cover all cases.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
These two objects are used to access fields in actual ethernet packets
captures with libpcap, so it's essential that they don't change size
for any reason. This patch uses gnulib's verify() macro to make sure
their sizes don't change.
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Allow the possibility of opening a connection to only the storage
driver, by defining a nwfilter:///system URI and registering a fake
hypervisor driver that supports it.
The hypervisor drivers can now directly open a nwfilter driver
connection at time of need, instead of having to pass around a
virConnectPtr through many functions. This will facilitate the later
change to support separate daemons for each driver.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The unprivileged libvirtd does not support nwfilter config, by leaves the
driver active. It is supposed to result in all APIs being an effective
no-op, but several APIs rely on driver->nwfilters being non-NULL, or they
will reference a NULL pointer. Rather than adding checks for NULL in many
places, just make sure driver->nwfilters is always initialized.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Right-aligning backslashes when defining macros or using complex
commands in Makefiles looks cute, but as soon as any changes is
required to the code you end up with either distractingly broken
alignment or unnecessarily big diffs where most of the changes
are just pushing all backslashes a few characters to one side.
Generated using
$ git grep -El '[[:blank:]][[:blank:]]\\$' | \
grep -E '*\.([chx]|am|mk)$$' | \
while read f; do \
sed -Ei 's/[[:blank:]]*[[:blank:]]\\$/ \\/g' "$f"; \
done
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Found by Coverity. If virNWFilterHashTablePut, then the 3rd arg @val
must be free'd since it would be leaked.
This also fixes potential problem on the error path where the caller
could assume the virNWFilterHashTablePut was successful when in fact
it failed leading to other issues.
Rather than using loop break;'s in order to force a return
of rc = -1, let's just return -1 immediately on the various
error paths and then return 0 on the success path.
On pure success paths, virNWFilterIPAddrMapAddIPAddr was validly
consuming the input @addr; however, on failure paths it was possible
that virNWFilterVarValueCreateSimple succeed, but virNWFilterHashTablePut
failed resulting in virNWFilterVarValueFree being called to clean
up @val which also cleaned up the input @addr. Thus the caller had
no way to determine on failure whether it too should clean up the
passed parameter.
Instead, let's create a copy of the input @addr, then handle that
properly in the API allowing/forcing the caller to free it's own
copy of the input parameter.
New API will be virNWFilterInstantiateFilterInternal as it's called from
the virNWFilterInstantiateFilter and virNWFilterUpdateInstantiateFilter.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Rename to virNWFilterDoInstantiate to better describe the action.
Also fix the @vmuuid parameter to not have the ATTRIBUTE_UNUSED since it
is used in the call to virNWFilterDHCPSnoopReq.
Signed-off-by: John Ferlan <jferlan@redhat.com>
The HOST_NAME_MAX, INET_ADDRSTRLEN and VIR_LOOPBACK_IPV4_ADDR
constants are only used by a handful of files, so are better
kept in virsocketaddr.h or the source file that uses them.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Rather than "wait" for the first config file to be created, force creation
of the configDir during driver state initialization.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Essentially virNWFilterSaveDef executed in a different order the same
sequence of calls, so let's just make one point of reference.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Rather than separate calls, use a common call and generate a better
error message which includes the incorrect uuidstr.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Move from virnwfilterobj.h to virnwfilterobj.c.
Create the virNWFilterObjListNew() API in order to allocate.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Move the structure to virnwfilterobj.c and create necessary accessor API's
for the various fields.
Also make virNWFilterObjFree static since there's no external callers.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Rather than dereferencing obj->def->XXX or nwfilters->objs[i]->X
create local virNWFilterObjPtr and virNWFilterDefPtr variables.
Future adjustments will be privatizing the object more, so this just
prepares the code for that reality.
Signed-off-by: John Ferlan <jferlan@redhat.com>
When processing a virNWFilterPtr use 'nwfilter' as a variable name.
When processing a virNWFilterObjPtr use 'obj' as a variable name.
Signed-off-by: John Ferlan <jferlan@redhat.com>
