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>
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 adds test cases for parsing of parameters with
multiple occurrances of the same name.
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 a test case for testing the XML parser's and instantiator's
support of the state attribute. The other test case tests existing
capabilities. Both test cases will be used in TCK again.
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.
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
Stefan Berger