On Sun, May 04, 2014 at 11:04:29PM +0400, Vasily Averin wrote: > On 05/04/2014 04:54 PM, Pablo Neira Ayuso wrote: > > On Wed, Apr 30, 2014 at 12:54:50PM +0400, Vasily Averin wrote: > >> Currently bridge can silently drop ipv4 fragments. > >> If node have loaded nf_defrag_ipv4 module but have no nf_conntrack_ipv4, > >> br_nf_pre_routing defragments incoming ipv4 fragments > >> but nfct check in br_nf_dev_queue_xmit does not allow re-fragment combined packet back, > >> and therefore it is dropped in br_dev_queue_push_xmit without incrementing of any failcounters > > > > If no further objections, I'll push this original patch appending this comment > > to the description: > > > > [ It seems the only way to hit the ip_fragment code in the bridge xmit > > path is to have a fragment list whose reassembled fragments go over > > the mtu. This only happens if nf_defrag is enabled. Thanks to > > Florian Westphal for providing feedback to clarify this. ] > > I have not objections, however I still do not understand why #if > IS_ENABLED(CONFIG_NF_CONNTRACK_IPV4) is required in > br_dev_queue_push_xmit()? > > If ipv4 defragmentation is required not only for conntracks but for > TPROXY target and xt_socket match I think we need to use > NF_DEFRAG_IPV4 instead. Before your patch, this was checking for skb->nfct which is defined by #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) in include/linux/skbuff.h. But after removing that skb->nfct check, we can safely change it to CONFIG_NF_DEFRAG_IPV4. You can send me a new patch version including this change. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
