maybe because the packet is sent firstly to the router and then the router sends to my host a ip packet in which network_header is set? i hope so... On Wed, Sep 1, 2010 at 1:48 PM, Nicola Padovano <nicola.padovano@xxxxxxxxx> wrote: > ok, Jan! Perfect. > > But there is a last question: i've seen a source code that get a > packet just received from the Net: so -if I understand correctly- it > can't use skb_network_header (IP header) because when i get a packet > just received from the net i should have only the mac_header set. > isn't it? > But, i've seen the usage of skb_network_header... > > On Wed, Sep 1, 2010 at 12:53 PM, Jan Engelhardt <jengelh@xxxxxxxxxx> wrote: >> On Wednesday 2010-09-01 11:57, Nicola Padovano wrote: >> >>>"If a packet is handled by a bridge, that is, a component that does not >>>deal with layer 3 or 4, there is no point in spending time to find the >>>start of the layer 3/4 header." >>> >>>Ok, well: great. but in this case (bridge) also the skb_network_header >>>function is senseless because we don't have to find layer3 header. >>>isn't it? >> >> Correct. >> >>>in general: when i can use the skb_transport_header function? >> >> When a transport header pointer has been set. Which is when the >> appropriate layer-X function has processed it. (After ip_rcv for >> example) >> On the output path, since it goes in the reverse direction, it will >> always be set. >> >> > > > > -- > Nicola Padovano > e-mail: nicola.padovano@xxxxxxxxx > web: http://npadovano.altervista.org > -- Nicola Padovano e-mail: nicola.padovano@xxxxxxxxx web: http://npadovano.altervista.org -- 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
