ok.thanks. now is all clear...so if i write a new target for NFPROTO_IPV4, the packet that i firstly receive in my target-hook function is an _IP_ packet. isn't it? On Wed, Sep 1, 2010 at 2:18 PM, Nicola Padovano <nicola.padovano@xxxxxxxxx> wrote: > 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 > -- 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
