从内核模块内部发送原始以太网数据包 [英] Send a raw ethernet packet from inside a kernel module

问题描述

我发现我需要的内核模块中建立一个新的sk_buff结构，并把它传递给我的网络设备，但我无法弄清楚是如何设置的结构变量的简单原始的以太网数据包。

I found out that I need to build a new sk_buff struct in the kernel module and pass it to my network device, but what I can't figure out is how to set the struct variables for a simple raw ethernet packet.

这必须是容易的，但我真的AP preciate它，如果有人可以给我如何把sk_buff的一起样本code。

This has to be easy, but i would really appreciate it, if someone could give me a sample code of how to put the sk_buff together.

推荐答案

看看在网​​/包/ af_packet功能 packet_sendmsg_spkt 。 ç寻找灵感。难的是得到一个结构袜子，如果你没有一个插座...

Take a look at the function packet_sendmsg_spkt in net/packet/af_packet.c for inspiration. The hard part is getting a struct sock if you don't have a socket...

编辑：添加一个基本的code shell中：

Added a basic code shell:

int sendpacket(struct socket *sock, struct net_device *dev, __be16 proto, void *data, size_t len)
{
    struct sock *sk = sock->sk;
    struct sk_buff *skb;

    if (!(dev->flags & IFF_UP))
        return -ENETDOWN;

    if (len > dev->mtu + dev->hard_header_len)
        return -EMSGSIZE;

    skb = sock_wmalloc(sk, len + LL_RESERVED_SPACE(dev), 0, GFP_KERNEL);

    if (skb == NULL)
        return -ENOBUFS;

    /* FIXME: Save some space for broken drivers that write a
     * hard header at transmission time by themselves. PPP is the
     * notable one here. This should really be fixed at the driver level.
     */
    skb_reserve(skb, LL_RESERVED_SPACE(dev));
    skb_reset_network_header(skb);

    /* Try to align data part correctly */
    if (dev->header_ops) {
        skb->data -= dev->hard_header_len;
        skb->tail -= dev->hard_header_len;
        if (len < dev->hard_header_len)
            skb_reset_network_header(skb);
    }

    memcpy(skb_put(skb, len), data, len);
    skb->protocol = proto;
    skb->dev = dev;
    skb->priority = sk->sk_priority;

    dev_queue_xmit(skb);

    return len;
}

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