Ask for link and address data on the same socket.
Thomas Graf
tgraf at suug.ch
Thu Jul 18 13:28:02 EDT 2013
On 07/18/13 at 05:15pm, Tilman Baumann wrote:
> On 11/07/13 20:32, Thomas Graf wrote:
> > On 07/10/13 at 03:48pm, Tilman Baumann wrote:
> >> On 04/07/13 20:55, Thomas Graf wrote:
> >>
> >> The parse part can deal with both types of responses very well.
> >> Do you mean I should send the requests individually via send() and with
> >> NLMSG_DONE?
> >> Or assemble the request chain how I did with NLMSG_NEXT() and a empty or
> >> rtgenmsg request with NLMSG_DONE at the end?
> > The kernel is not ready to handle that.
> >
> > I suggest that you use individual send() calls to send the RTM_GETADDR
> > and RTM_GETLINK requests so you don't need to send a NLMSG_DONE
> > message at all.
> Thanks again for taking your time.
>
> I simplified the code a bit. Too much cargo cult going on. (Still the
> case, but I think I grokk it)
>
> I assemble two messages, one RTM_GETLINK and one RTM_GETADDR, and send
> them individually.
> But my receive function again only receives the first one.
>
> I think I'm still missing a clue here.
> If you like I can send you my receive function.
>
> My request function now:
> {
> int status;
> struct {
> struct nlmsghdr n;
> struct ifaddrmsg r;
> } ifaddr_req;
>
> struct {
> struct nlmsghdr n;
> struct ifinfomsg r;
> } ifinfo_req;
>
> memset(&ifaddr_req, 0, sizeof(ifaddr_req));
> ifaddr_req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
> ifaddr_req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
> ifaddr_req.n.nlmsg_type = RTM_GETADDR;
>
> status = send(netlinkfd, &ifaddr_req, ifaddr_req.n.nlmsg_len, 0);
> if (status < 0) {
> perror("[Listener] send");
> return 1;
> }
You should receive the answer to the first request here.
> memset(&ifinfo_req, 0, sizeof(ifinfo_req));
> ifinfo_req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
^^^^^^^^^^^^^^
> ifinfo_req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
> ifinfo_req.n.nlmsg_type = RTM_GETLINK;
>
> status = send(netlinkfd, &ifinfo_req, ifinfo_req.n.nlmsg_len, 0);
> if (status < 0) {
> perror("[Listener] send");
> return 1;
> }
> return 1;
> }
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