Pablo Neira Ayuso <pa...@netfilter.org> wrote: > > How so? > > So this is there just to cover the fail the ENOSPC when setting label?
No label extension present or skb->nfct is untracked. -m label --label bit40 will never match if the packet has no conntrack attached. "-m label --label bit40 --set" will behave the same in that case. I would really prefer to expose this 1:1 in the translation because it matches the behaviour. Users that don't care about success can always just "ct label set foo". > This internal behaviour in xt connlabel seems confusing to me, this > rule: > > iptables -A INPUT -m connlabel ! --label bit40 --set > > following the reading from left to right convention tells me: > > if not bit40 set, then set it. If not set, then *try* to set it: if (ct == NULL || nf_ct_is_untracked(ct)) return invert; if (info->options & XT_CONNLABEL_OP_SET) return (nf_connlabel_set(ct, info->bit) == 0) ^ invert; return connlabel_match(ct, info->bit) ^ invert; > But this is actually setting in first place inconditionally, then > checking this is not set, what is the use case for this? The xt module doesn't have to recheck, if nf_connlabel_set returns 0 then the bit will be set. > Actually the kernel code first sets the bit, then checks if this is > unset for this. Note iptables-save displays this in that way as > output. > > You can probably introduce in iptables something like: > > iptables -A INPUT -m connlabel --set-label bit40 This is identical to iptables -A INPUT -m connlabel --label bit40 --set ... unless you meant that this "--set-label bit40" should always return true even if skb->nfct is NULL, but that seems wrong to me. It would be more xtables-style to add -j CONNLABEL --set-bit40 [ i.e. XT_CONTINUE regardless if we could set anything ] But that doesn't make xtables any better and provides no benefit to end users. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
