于 2012年05月25日 14:02, Gao feng 写道: > 于 2012年05月25日 10:54, Pablo Neira Ayuso 写道: >> On Fri, May 25, 2012 at 09:05:34AM +0800, Gao feng wrote: >>> 于 2012年05月24日 22:38, Pablo Neira Ayuso 写道: >>>> On Thu, May 24, 2012 at 06:54:42PM +0800, Gao feng wrote: >>>> [...] >>>>>>>> I don't see why we need this new field. >>>>>>>> >>>>>>>> It seems to be set to 1 in each structure that has set: >>>>>>>> >>>>>>>> .ctl_compat_table >>>>>>>> >>>>>>>> to non-NULL. So, it's redundant. >>>>>>>> >>>>>>>> Moreover, you already know from the protocol tracker itself if you >>>>>>>> have to allocate the compat ctl table or not. >>>>>>>> >>>>>>>> In other words: You set compat to 1 for nf_conntrack_l4proto_generic. >>>>>>>> Then, you pass that compat value to generic_init_net via ->inet_net >>>>>>>> again, but this information (that determines if the compat has to be >>>>>>>> done or not) is already in the scope of the protocol tracker. >>>>>>>> >>>>>>> >>>>>>> because some protocols such l4proto_tcp6 and l4proto_tcp use the same init_net >>>>>>> function. the l4proto_tcp6 doesn't need compat sysctl, so we should use this new >>>>>>> field to identify if we should kmemdup compat_sysctl_table. >>>>>> >>>>>> Then, could you use two init_net functions? one for TCP for IPv4 and another >>>>>> for TCP for IPv6? >>>>> >>>>> Of cause, if you prefer to impletment it in this way. >>>> >>>> If this removes the .compat field that you added, then use two >>>> init_net functions, yes. >>> >>> Sorry I miss something. >>> >>> nf_ct_l4proto_unregister_sysctl also uses .compat to identify if we >>> can unregister the compat sysctl. >>> >>> if we register l4proto_tcp and l4proto_tcp6 both. without .compat, >>> when unregister l4proto_tcp6, the compat sysctl will be unregister too. >>> >>> So maybe we have to use .compat. >> >> Could you resolve this by checking pn->ctl_compat_header != NULL ? > > pn->ctl_table_header and ctl_compat_header is shared by l4proto_tcp and l4proto_tcp6. > if we both register l4proto_tcp and l4proto_tcp6, when unregister l4proto_tcp6 > pn->ctl_compat_header must not be NULL. > Maybe we can resolve this by nf_conntrack_l4proto.l3proto == AF_INET && pn->ctl_compat_header != NULL Because compat sysctl is registered by AF_INET's proto only. -- 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
