Re: [libvirt] [PATCH v2] nwfilters: support for TCP flags evaluation
On 04/07/2011 05:47 PM, Eric Blake wrote:
On 04/07/2011 01:47 PM, Stefan Berger wrote:
> 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>
>
>
> Signed-off-by: Stefan Berger<stefanb(a)linux.vnet.ibm.com>
>
> ---
> docs/formatnwfilter.html.in | 10 ++
> docs/schemas/nwfilter.rng | 16 ++++
> src/conf/nwfilter_conf.c | 115
> +++++++++++++++++++++++++++---
> src/conf/nwfilter_conf.h | 9 ++
> src/libvirt_private.syms | 1
> src/nwfilter/nwfilter_ebiptables_driver.c | 9 ++
> tests/nwfilterxml2xmlin/tcp-test.xml | 12 +++
> tests/nwfilterxml2xmlout/tcp-test.xml | 12 +++
> 8 files changed, 174 insertions(+), 10 deletions(-)
ACK, looks reasonable to me, with one optimization nit fixed:
> + int32_t mask = 0x1;
>
> - for (i = 0; int_map[i].val; i++) {
> - if (last_attr != int_map[i].attr&&
> - flags& int_map[i].attr) {
> - if (c>= 1)
> - virBufferVSprintf(buf, "%s", sep);
> - virBufferVSprintf(buf, "%s", int_map[i].val);
> - c++;
> + while (mask) {
> + if ((mask& flags)) {
> + for (i = 0; int_map[i].val; i++) {
> + if (mask == int_map[i].attr) {
> + if (c>= 1)
> + virBufferVSprintf(buf, "%s", sep);
> + virBufferVSprintf(buf, "%s", int_map[i].val);
> + c++;
> + }
> + }
> + flags ^= mask;
> + if (!flags)
> + break;
This if condition should be after...
> }
this brace; otherwise, if flags == 0 on entry, then you will
(needlessly) iterate through all 32 bits of mask, rather than breaking
on the first iteration.
Excellent! I'll modify and push.
Stefan