Hi,
How about adding these lines...
len is the length of your data..
skb->len = sizeof(struct nlmsghdr) + len;
skb->tail = skb->data + skb->len;
skb->truesize = skb->len;
netlink_unicast (nl_sk, skb, pid, MSG_DONTWAIT);
On 7/20/05, Tan, Chiang Kang <Chiang.Tan@xxxxxxxxxxxxxxx> wrote:
> Hi all,
> Actually I have this problem, which is more fundamental really. I
> wanted to create a new message to send to the userspace. However everytime
> I try to do so, using netlink_unicast, 0 bytes is sent. The listening
> userspace application (using recvmsg) confirms that 0 bytes is received,
> so I think a message IS sent from the kernel, but I don't understand why
> I'm unable to send the entire message properly. Below is the code
>
> skb_nl = alloc_skb(NLMSG_SPACE(MAX_PAYLOAD), GFP_ATOMIC);
>
> if (skb_nl == NULL) {
> printk("%s: skb allocation fails!\n", __FUNCTION__);
> goto out;
> }
>
> nlh = (struct nlmsghdr *)skb_nl->data;
>
> /* Fill in the netlink message header */
> nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
> nlh->nlmsg_pid = 0;
> nlh->nlmsg_flags = 0;
> /* Fill in the netlink message payload */
> strcpy(NLMSG_DATA(nlh), "Greeting from kernel!");
>
> NETLINK_CB(skb_nl).groups = 0; /* not in mcast group */
> NETLINK_CB(skb_nl).pid = 0; /* from kernel */
> NETLINK_CB(skb_nl).dst_pid = nlq_pid; /* pid of userspace process */
> NETLINK_CB(skb_nl).dst_groups = 0; /* unicast */
>
> err = netlink_unicast(nl_sk, skb_nl, nlq_pid, MSG_DONTWAIT);
>
> I really do hope someone can shed some light from this problem.
> Thank you in advanced.
>
> cheers
> Chiang
>
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
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>
>
--
cheers,
jonathan khoo
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Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
