Netfilter module name oddity

Netfilter module name oddity

Rami Rosen rosenrami at gmail.com
Sun May 31 11:23:19 IDT 2009


Hello,
All this is true, but I just want to add these two points:
In Ira mail, he mentions many modules which start with xt_* like:
	
10809   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_connmark.ko
12079   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_CONNMARK.ko
10066   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_dscp.ko
11193   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_DSCP.ko
9885    /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_mark.ko
10903   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_MARK.ko
10137   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_rateest.ko
13381   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_RATEEST.ko
9193    /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_tcpmss.ko
12506   /lib/modules/2.6.26-1-amd64/kernel/net/netfilter/xt_TCPMSS.ko

First, it is true also for these modules, that when you see lower case it is a
matching module, and when you see upper case it is a target module.
(most of them, if not all, have also MODULE_ALIAS to a corresponding ipt_*.)

And second: there are no ipt_* modules under net/netfilter; only xt_* modules.
the difference between the ipt_* modules, which reside under
net/ipv4/netfilter (like net/ipv4/netfilter/ipt_ecn.c,
net/ipv4/netfilter/ipt_ECN.c, net/ipv4/netfilter/ipt_LOG.c and more)
and the xt_* modules under net/netfilter is that (naturally) the
ipt_* modules under net/ipv4/netfilter handle only IPV4 packets
(The family member of the target (xt_target) or of the match (xt_match) is
NFPROTO_IPV4), while the xt_* modules (under /net/netfilter) support is not
limited to IPV4 (They have usually NFPROTO_UNSPEC or have targets/matches
arrays with both NFPROTO_IPV4 and NFPROTO_IPV6).

Regards,
Rami Rosen



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