nwfilter.rng defines uint16range and uint32range, but in a different
manner (it also allows a variable name as the value, rather than just
a decimal or hex number). I wanted to add uint16range to
basictypes.rng, but my desired definition was parallel to those for
uint8range and uint24range which are defined in basictypes.rng - they
*don't* allow a variable name for the value.
The simplest path to make everyone happy is to make the "plain"
versions in basictypes.rng have simpler names - "uint8", "uint16", and
"uint24". This patch renames uint8range and uint24range to uint8 and
uint24, while the next patch will add uint16.
Make use of the ebtables functionality to be able to filter certain
parameters of icmpv6 packets. Extend the XML parser for icmpv6 types,
type ranges, codes, and code ranges. Extend the nwfilter documentation,
schema, and test cases.
Being able to filter icmpv6 types and codes helps extending the DHCP
snooper for IPv6 and filtering at least some parameters of IPv6's NDP
(Neighbor Discovery Protocol) packets. However, the filtering will not
be as good as the filtering of ARP packets since we cannot
check on IP addresses in the payload of the NDP packets.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
The 'trang' utility, which is able to transform '.rng' files into
'.rnc' files, reported some errors in our schemas that weren't caught
by the tools we use in the build. I haven't added a test for this,
but the validity can be checked by the following command:
trang -I rng -O rnc domain.rng domain.rnc
There were unescaped minuses in regular expressions and we were
constraining int (which is by default in the range of [-2^31;2^31-1]
to maximum of 2^32. But what we wanted was exactly an unsignedInt.
This patch adds support for the recent ipset iptables extension
to libvirt's nwfilter subsystem. Ipset allows to maintain 'sets'
of IP addresses, ports and other packet parameters and allows for
faster lookup (in the order of O(1) vs. O(n)) and rule evaluation
to achieve higher throughput than what can be achieved with
individual iptables rules.
On the command line iptables supports ipset using
iptables ... -m set --match-set <ipset name> <flags> -j ...
where 'ipset name' is the name of a previously created ipset and
flags is a comma-separated list of up to 6 flags. Flags use 'src' and 'dst'
for selecting IP addresses, ports etc. from the source or
destination part of a packet. So a concrete example may look like this:
iptables -A INPUT -m set --match-set test src,src -j ACCEPT
Since ipset management is quite complex, the idea was to leave ipset
management outside of libvirt but still allow users to reference an ipset.
The user would have to make sure the ipset is available once the VM is
started so that the iptables rule(s) referencing the ipset can be created.
Using XML to describe an ipset in an nwfilter rule would then look as
follows:
<rule action='accept' direction='in'>
<all ipset='test' ipsetflags='src,src'/>
</rule>
The two parameters on the command line are also the two distinct XML attributes
'ipset' and 'ipsetflags'.
FYI: Here is the man page for ipset:
https://ipset.netfilter.org/ipset.man.html
Regards,
Stefan
This patch introduces the capability to use a different iterator per
variable.
The currently supported notation of variables in a filtering rule like
<rule action='accept' direction='out'>
<tcp srcipaddr='$A' srcportstart='$B'/>
</rule>
processes the two lists 'A' and 'B' in parallel. This means that A and B
must have the same number of 'N' elements and that 'N' rules will be
instantiated (assuming all tuples from A and B are unique).
In this patch we now introduce the assignment of variables to different
iterators. Therefore a rule like
<rule action='accept' direction='out'>
<tcp srcipaddr='$A[@1]' srcportstart='$B[@2]'/>
</rule>
will now create every combination of elements in A with elements in B since
A has been assigned to an iterator with Id '1' and B has been assigned to an
iterator with Id '2', thus processing their value independently.
The first rule has an equivalent notation of
<rule action='accept' direction='out'>
<tcp srcipaddr='$A[@0]' srcportstart='$B[@0]'/>
</rule>
This patch adds support for filtering of STP (spanning tree protocol) traffic
to the parser and makes us of the ebtables support for STP filtering. This code
now enables the filtering of traffic in chains with prefix 'stp'.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
With hunks borrowed from one of David Steven's previous patches, we now
add the capability of having a 'mac' chain which is useful to filter
for multiple valid MAC addresses.
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
This patch adds support for filtering of VLAN (802.1Q) traffic to the
parser and makes us of the ebtables support for VLAN filtering. This code
now enables the filtering of traffic in chains with prefix 'vlan'.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
This patch modifies the NWFilter parameter parser to support multiple
elements with the same name and to internally build a list of items.
An example of the XML looks like this:
<parameter name='TEST' value='10.1.2.3'/>
<parameter name='TEST' value='10.2.3.4'/>
<parameter name='TEST' value='10.1.1.1'/>
The list of values is then stored in the newly introduced data type
virNWFilterVarValue.
The XML formatter is also adapted to print out all items in alphabetical
order sorted by 'name'.
This patch also fixes a bug in the XML schema on the way.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
This patch enables chains that have a known prefix in their name.
Known prefixes are: 'ipv4', 'ipv6', 'arp', 'rarp'. All prefixes
are also protocols that can be evaluated on the ebtables level.
Following the prefix they will be automatically connected to an interface's
'root' chain and jumped into following the protocol they evaluate, i.e.,
a table 'arp-xyz' will be accessed from the root table using
ebtables -t nat -A <iface root table> -p arp -j I-<ifname>-arp-xyz
thus generating a 'root' chain like this one here:
Bridge chain: libvirt-O-vnet0, entries: 5, policy: ACCEPT
-p IPv4 -j O-vnet0-ipv4
-p ARP -j O-vnet0-arp
-p 0x8035 -j O-vnet0-rarp
-p ARP -j O-vnet0-arp-xyz
-j DROP
where the chain 'arp-xyz' is accessed for filtering of ARP packets.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
This patch extends the filter XML to support priorities of chains
in the XML. An example would be:
<filter name='allow-arpxyz' chain='arp-xyz' priority='200'>
[...]
</filter>
The permitted values for priorities are [-1000, 1000].
By setting the priority of a chain the order in which it is accessed
from the interface root chain can be influenced.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
This patch enables filtering of gratuitous ARP packets using the following XML:
<rule action='accept' direction='in' priority='425'>
<arp gratuitous='true'/>
</rule>
This patch adds support for the evaluation of TCP flags in nwfilters.
It adds documentation to the web page and extends the tests as well.
Also, the nwfilter schema is extended.
The following are some example for rules using the tcp flags:
<rule action='accept' direction='in'>
<tcp state='NONE' flags='SYN/ALL' dsptportstart='80'/>
</rule>
<rule action='drop' direction='in'>
<tcp state='NONE' flags='SYN/ALL'/>
</rule>
This patch adds the possibility to not just drop packets, but to also have them rejected where iptables at least sends an ICMP msg back to the originator. On ebtables this again maps into dropping packets since rejecting is not supported.
I am adding 'since 0.8.9' to the docs assuming this will be the next version of libvirt.
This patch adds an optional XML attribute to a nwfilter rule to give the user control over whether the rule is supposed to be using the iptables state match or not. A rule may now look like shown in the XML below with the statematch attribute either having value '0' or 'false' (case-insensitive).
[...]
<rule action='accept' direction='in' statematch='false'>
<tcp srcmacaddr='1:2:3:4:5:6'
srcipaddr='10.1.2.3' srcipmask='32'
dscp='33'
srcportstart='20' srcportend='21'
dstportstart='100' dstportend='1111'/>
</rule>
[...]
I am also extending the nwfilter schema and add this attribute to a test case.
So far the references to other filters needed to appear before filtering
rules. With the below patch they can now appear in any order.
Also I forgot to add a couple of 'rarp's.
This patch adds support for the RARP protocol. This may be needed due to
qemu sending out a RARP packet (at least that's what it seems to want to
do even though the protocol id is wrong) when migration finishes and
we'd need a rule to let the packets pass.
Unfortunately my installation of ebtables does not understand -p RARP
and also seems to otherwise depend on strings in /etc/ethertype
translated to protocol identifiers. Therefore I need to pass -p 0x8035
for RARP. To generally get rid of the dependency of that file I switch
all so far supported protocols to use their protocol identifier in the
-p parameter rather than the string.
I am also extending the schema and added a test case.
changes from v1 to v2:
- added test case into patch
With this patch I want to enable hex number inputs in the filter XML. A
number that was entered as hex is also printed as hex unless a string
representing the meaning can be found.
I am also extending the schema and adding a test case. A problem with
the DSCP value is fixed on the way as well.
Changes from V1 to V2:
- using asHex boolean in all printf type of functions to select the
output format in hex or decimal format
This patch adds a relaxng nwfilter schema along with a test that
verifies all the test output XML against the schema. The input XMLs
contain a lot of intentional out-of-range values that make them fail the
schema verification, so I am not verifying against those.
