On 12/09/2011 08:07 AM, Stefan Berger wrote:
This patch adds documentation about the new 'ways' that users can access the contents of variables in filters:
- access via index: $TEST[2] - access via iterators $TEST[@1]
--- docs/formatnwfilter.html.in | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)
Index: libvirt-iterator/docs/formatnwfilter.html.in =================================================================== --- libvirt-iterator.orig/docs/formatnwfilter.html.in +++ libvirt-iterator/docs/formatnwfilter.html.in @@ -308,7 +308,37 @@ </rule> ... </pre> - + <p> + <span class="since">Since 0.9.9</span> it is possible to access
We missed the release; s/0.9.9/0.9.10/
+ individual elements of a variable holding a list of elements. + A filtering rule like the following accesses the 2nd element + of the variable DSTPORTS. + </p> +<pre> + ... + <rule action='accept' direction='in' priority='500'> + <udp dstportstart='$DSTPORTS[1]'/> + </rule> + ... +</pre> + <p> + <span class="since">Since 0.9.9</span> it is possible to create
Likewise.
+ filtering rules that instantiate all combinations of rules from + different lists using the notation of + <code>$VARIABLE[@<iterator ID>]</code>. + The following rule allows a virtual machine to + receive traffic on a set of ports, which are specified in DSTPORTS, + from the set of source IP address specified in SRCIPADDRESSES. + The rule generates all combinations of elements of the variable + DSTPORT with those of SRCIPADDRESSES.
I would also mention: $VARIABLE is short-hand for $VARIABLE[@0]. When combining variables, each variable that uses the same iterator ID will be directly combined; it is the use of different iterator IDs that causes all combinations to be generated. And maybe even mention an example: If variable A is the list [1, 2], and variable B is the list [3, 4], then combining $A[@0] and $B[@0] produces the list [1/3, 2/4], while combining $A[@0] and $B[@1] produces the list [1/3, 1/4, 2/3, 2/4]. Overall, I like what is in this series, but I think I had enough minor findings that it would be worth posting a v2 before pushing anything. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org