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. -- 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
