Porting conntrack modules

Many new versions of Linux 2.6 used to change the Netfilter API. This page provides documentation on how to port connection tracking modules to these new versions.

Linux 2.6.13

• ip_conntrack_expect_alloc(): parameters changed

  -exp = ip_conntrack_expect_alloc(); +exp = ip_conntrack_expect_alloc(ct);

• ip_conntrack_expect_free(): replaced with ip_conntrack_expect_put() (implementing a usage counter); must call ip_conntrack_expect_put() after ip_conntrack_expect_related()

  int ret; -exp = ip_conntrack_expect_alloc(); +exp = ip_conntrack_expect_alloc(ct); if (exp == NULL) return NF_ACCEPT; if (ip_nat_FOO_hook != NULL) { ret = ip_nat_FOO_hook(pskb, ctinfo, i, exp); } else { if (ip_conntrack_expect_related(exp) != 0) { ret = NF_DROP; } else { ret = NF_ACCEPT; } } +ip_conntrack_expect_put(exp); return ret;

  Note that all execution branches result in ip_conntrack_expect_put() being called at the end.