On Friday 22 October 2004 05:51 pm, Eric Bambach wrote:
> On Wednesday 20 October 2004 08:17 pm, Eric Bambach wrote:
> > Hello,
>
> In response to my previous message, maybe my questions were not specific
> enough. I have been debugging/understanding the code for a little time now
> and constantly run into this problem. I get a SIGSEGV here
>
Hello again code gurus :)
Yes another fight in my netlink saga. Thanks to all who have replied before
and I have learned alot from the rfc's and zebra/iproute and have contructed
a much more robust implementation. I have sent the kernel a message defined
as below. However I have not learned what exactly I should be expecting from
the kernel. That is, my message gets a reply from the kernel about eth0,
however on my machine i have eth0,1,2,ppp0 and I would like information about
them all. I have NLM_F_ROOT set on the packet as I was under the impression
that this would dump information about all the interfaces. I have also tried
incrementing msg.info.ifi_index to 0,1,2,3 etc. No matter what these values
I always recieve this output form my program.
#./nl_test_prog
Found device: eth0 - 1
Found address: <--(Dont care about blank yet, main problem is only
1 if shows. This is minor)
-Am I wrong to expect the kernel to send me data about all the interfaces?
-Am I calling this wrong?
-What can I do to query all the interfaces?
I do loop through all the rta messages and I receive only 1 packet from the
kernel when calling recvmsg(). I have also tried without OR'ing NLM_F_MATCH.
I have run it through a debugger and confirmed although there are multiple
RTA atributes in my netlink packet, they all refer to eth0.
-Should I be expecting multiple packets (NLM_F_MULTI)?
Here is my nl_packet construction.
msg.hdr.nlmsg_len = sizeof(msg);
msg.hdr.nlmsg_type = RTM_GETLINK;
msg.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT | NLM_F_MATCH;
msg.hdr.nlmsg_pid = getpid();
msg.hdr.nlmsg_seq = seq++;
msg.info.ifi_family = AF_UNSPEC; //AF_UNSPEC for ipv4
msg.info.ifi_type = NETLINK_ROUTE;
msg.info.ifi_index = 0;
msg.info.ifi_change = (0-1);
----------------Looping over the attributes later in code--------------
/* Loop over the attributes in this message */
while(RTA_OK(rta, len))
{
switch(rta->rta_type)
{
case IFLA_IFNAME:
cout << "Found device: " << (char *)RTA_DATA(rta)<< " - " <<
info->ifi_index << endl;
break;
case IFLA_ADDRESS:
cout << "Found address: " << (char *)RTA_DATA(rta) << endl;
break;
}
rta = RTA_NEXT(rta, len);
/* We hit the next packet */
}// Packet Looping while()
More info/code available upon request.
Any help would be appreciated.
----------------------------------------
EB
> All is fine except that I can reliably "oops" it simply by trying to read
> from /proc/apm (e.g. cat /proc/apm).
> oops output and ksymoops-2.3.4 output is attached.
> Is there anything else I can contribute?
The latitude and longtitude of the bios writers current position, and
a ballistic missile.
--Alan Cox 2000-12-08
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