BORBELY Zoltan wrote: > Hi, > > I'm developing a transparent user space ftp proxy, and I'm using expect > entries to accept incoming data connections. It works quite well, but I > had to patch the kernel to get it work. It's quite small, so I put it > inline: Just a wild thought. What if you create a new conntrack (instead of an expectation) using a small timeout in state TCP SYN_SENT that represents the new flow that it is expected to arrive? The first packet would seen as a resent by the connection tracking so it would accept it. However, the TCP sequence tracking may complain about it. Nevertheles, we can also access to the internal TCP flags to enable IP_CT_TCP_FLAG_BE_LIBERAL. > --- nf_conntrack_netlink-orig-2.6.22.9.c 2007-09-26 20:03:01.000000000 +0 > +++ nf_conntrack_netlink-new-2.6.22.9.c 2008-06-13 17:14:17.000000000 +0200 > @@ -39,6 +39,7 @@ > #ifdef CONFIG_NF_NAT_NEEDED > #include <net/netfilter/nf_nat_core.h> > #include <net/netfilter/nf_nat_protocol.h> > +#include <net/netfilter/nf_nat_helper.h> > #endif > > #include <linux/netfilter/nfnetlink.h> > @@ -1439,7 +1440,11 @@ > goto out; > } > > - exp->expectfn = NULL; > + exp->expectfn = nf_nat_follow_master; > +#ifdef CONFIG_NF_NAT_NEEDED > + exp->saved_proto.tcp.port = tuple.dst.u.tcp.port; //!!!FIXME > + exp->dir = IP_CT_DIR_ORIGINAL; > +#endif > exp->flags = 0; > exp->master = ct; > exp->helper = NULL; > > It's ugly as hell in the current form, but I have some ideas how to > improve it to integrate it into the main kernel tree. Maybe we can add a > new CTA_EXPECT_SAVED_PROTO attribute and get it from user space. What > is your opinion? Would this change be generic enough for userspace transparent proxies or only for FTP? -- "Los honestos son inadaptados sociales" -- Les Luthiers -- 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
