Hi, 2017-03-02 18:18 GMT+08:00 Gao Feng <f...@ikuai8.com>: [...] > The expect class is NF_CT_EXPECT_CLASS_DEFAULT, and proto is > IPPROTO_UDP at the function "expect_rtp_rtcp", > And it makes sure the port is even number. > > But look at the process_gcf, the port is got from the packet data at > function get_h225_addr. > So it may be odd number. > It also would add one expect node whose class is > NF_CT_EXPECT_CLASS_DEFAULT, and proto is IPPROTO_UDP.
The nat_rtp_rtcp() is only invoked by expect_rtp_rtcp, and nf_nat_sdp_media() is only invoked by set_expected_rtp_rtcp. So the RTP port is ensured to be even, as well as the rtp_exp->tuple.dst.u.udp.port. Note: the rtp_exp is alloced by nf_ct_expect_alloc, and initialized by nf_ct_expect_init, then passed to nat_rtp_rtcp or nf_nat_sdp_media. So I cannot figure out why process_gcf will affect this? Or I missed something?
