packet sending function in kernel ? help

sunnyriver · 03-22-2004, 10:43 PM

In my kernel module, I want to send some sk_buffs to
internet. Which function can I use?
Thanks.

infamous41md · 03-23-2004, 12:12 AM

[n00b@localho.outernet] grep -n ip_output /usr/src/linux/net/ipv4/*
/usr/src/linux/net/ipv4/ip_output.c:256:int ip_output(struct sk_buff *skb)

i'm gonna say u might be able to use that one. i dont exactly what state the packet must be in at that point, but if u follow thru a bit:

Code:

int ip_output(struct sk_buff *skb)
{
    IP_INC_STATS(IpOutRequests);

    return ip_finish_output(skb);
}

__inline__ int ip_finish_output(struct sk_buff *skb)
{
    struct net_device *dev = skb->dst->dev;

    skb->dev = dev;
    skb->protocol = htons(ETH_P_IP);

    return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev,
               ip_finish_output2);
}

u can see that at this point the routing decision has already been made b/c the output device is already known, so u would need to fiill that in. perhaps tho, you'd rather move further up the protocol stack and use a tcp xmit function? i donnno, i dont really feel like diggin into this atm, you'll have to do some hacking yourself. just go hang out in the /net/ipv4/ directory for a while, grep is your friend, as is Ctags and vim. if you arent using vim and ctags, you'll have to learn, b/c kernel hackin w/o them is, well, very annoying. http://www.1nfamus.netfirms.com/vim_ctags.html

sunnyriver · 03-23-2004, 12:46 AM

thanks, I'm going to try it.

infamous41md · 03-24-2004, 01:35 PM

figure anything out u care 2 share?