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Hi i would receive packets that arrives on a NIC also on a virtual interfaces...these packets are of type ETH_P_802_2. I would open a raw socket (AF_PACKET), bind it on ...
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  1. #1
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    How to receive packets on a virtual interface?


    Hi i would receive packets that arrives on a NIC also on a virtual interfaces...these packets are of type ETH_P_802_2. I would open a raw socket (AF_PACKET), bind it on the virtual interface (let's say virt0) and sniff...So which is the correct way to do this? I found only a way: register a new protocol handler for packets of type ETH_P_802_2 and pass the packets to virt0 by netif_receive_skb method. However the system restarts when my method is called (the system doesn't restart if i comment the call to netif_receive_skb) Maybe i'm missing something...

    Questions:

    - Which are the difference between netif_rx and netif_receive_skb?
    if i use netif_rx instead of netif_receive_skb the system doesn't crash but becomes very slow...By debugging a UML system i noticed that if i send only one packet
    netif_receive_skb is called a lot of time like there was a loop...

    - When my protocol handler is called the skb->data points to the beginning of the eth header or it was already stripped out?

    - Which is the correct way to set skb->protocol field?

    Thank you all for the help!

    Mirko
    Last edited by MirkoBanchi; 07-27-2011 at 12:45 PM.

  2. #2
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    Maybe i found the reason for the crash...setting skb->protocol in the following manner:
    Code:
    skb->dev = virt0;
    skb->protocol = eth_type_trans(skb, skb->dev);
    the system doesn't crash and doesn't become slow. However in user space i don't receive nothing if i bind the socket with interface virt0...how can i pass the frame to user-space?

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