[Click] ToDevice(ath0) send: Massage too long

[Beyers Cronje]

Hi,

Unless you made a typo in your mail, one thing you're doing wrong is still
accessing pointer p after calling p->uniqueify(), which is invalid. The
proper way to use uniqueify() is as follows:

WritablePacket *q = p->uniqueify();
if (!q)
    return 0;
// p must not be used here.

Beyers

On Thu, Dec 9, 2010 at 3:32 PM, Becholey Alexandre <
alexandre.becholey at epfl.ch> wrote:

> Hi,
>
> I'm trying to create a click element that add a custom header between the
> mac header and the ip header. My element has 1 input (ethernet frames) and 1
> output (frames with the custom header).
> Here is the script:
> RatedSource
>    -> UDPIPEncap(my_ip, 254, dst_ip, 254)
>    -> EtherEncap(...) // I do this just to create some random ethernet
> frames
>    -> Print(1)
>    -> MyElement
>    -> Print(2)
>    -> EtherEncap(0x0800, my_mac, dst_mac)
>    -> Print(3)
>    -> Queue(2000)
>    -> ToDevice(ath0)
>
> Here is what my element does in his push function:
> struct my_custom_header my_header;
> my_header.n = 1; //an unsigned int
> my_header.addr = some_addr; //a struct in_addr
> WriteablePacket * encaped_pkt = p->uniqueify();
> encaped_pkt->pull(sizeof(click_ether));
> encaped_pkt = encaped_pkt->push(sizeof(my_custom_header_t));
> memcpy(p->data(), &my_header, sizeof(my_custom_header_t));
> output(0).push(p);
>
> With the Prints I can see that my header is correctly written in the
> packet:
> 1:    106 | ffffffff ffff0002 6fffff04 08004500 005c0113 0000fa11
> 2:    100 | 01000000 0a0a0a07 4500005c 01130000 fa11985b 0a0a0a04
> 3:    114 | ffffffff ffff0002 6fffff04 08000100 00000a0a 0a074500
> But then I get the "ToDevice(ath0) send: Message too long"
>
> I'm using click (userlevel) on an assus router running OpenWRT (8.09) with
> an atheros wifi card (madwifi driver).
> When I remove MyElement and the Following EtherEncap in the script, there
> is no problem (I can sniff the sent frames from another router with tcpdump
> for example).
>
> Any idee why? It's the first time I encounter this problem. I can without
> any problem create some packets (Packet::make(...)) and send them.
>
> Alexandre Becholey
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