How to receive UDP and ICMP packet using one UDP socket, (Path MTUD)

Dear All,

Can we configure one socket to receive two different protocols packet.
Like how can we made a UDP socket to receive udp as well as icmp
messages.

Actually I am implementing Path MTUD, so for that I sent some udp
probs to destination host, now I want that the same socket at client
side must be able to receive both udp response and icmp error
messages(like host unreachable, port unreachable etc).

Another approach is that, we will use two sockets for both source and
destination, form source we will send udp probs(through udp socket)
while at destination host, after receiving that prob(through udp
socket), application will make an icmp packet and sent it back to the
source host (using ICMP socket). And here at source host, that message
and other icmp error messages will be received by icmp socket.

But this approch dosen't look efficient to me, what u people say? If
Any one has another approch plz let me know.

Eagerly waiting for some +ve pings.

Rajat <(E-Mail Removed)> wrote:
> Dear All,
>
> Can we configure one socket to receive two different protocols packet.
> Like how can we made a UDP socket to receive udp as well as icmp
> messages.

You need to use two sockets and select() on them for readability. The
ICMP socket will need to be a RAW IP socket, IIRC, and will require root
priviledge.

Get yourself a copy of Unix Network Programming (3rd version is
the latest). I have the 2nd version, which I used for teaching network
programming last year. Its a truly great book that everyone will refer
you to in newsgroups.

You might also want to have a look to see what error (if any) you get on
your UDP packet when fragmentation is needed, but Don't Fragment is set.
You may need to use the recvmsg functions for this, plus maybe set some
socket options to turn on Don't Fragment.

Actually, I think UNP covers how to do Path MTUD in one of the
exercises, IIRC (it's at work, I can't currently check.)

--
Cameron Kerr
(E-Mail Removed) : http://nzgeeks.org/cameron/
Empowered by Perl!

Rajat wrote:

> Can we configure one socket to receive two different protocols packet.
> Like how can we made a UDP socket to receive udp as well as icmp
> messages.
>

?????

You don't!

--

Fundamentalism is fundamentally wrong.

To reply to this message, replace everything to the left of "@" with
james.knott.

i think you cant ..

since UDP and ICMP are really different binds, i dont think you can
make a socket from both at the same time. (SOCKET_UDP, SOCKET_RAW)

Andrew


"Rajat" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Dear All,
>
> Can we configure one socket to receive two different protocols packet.
> Like how can we made a UDP socket to receive udp as well as icmp
> messages.
>
> Actually I am implementing Path MTUD, so for that I sent some udp
> probs to destination host, now I want that the same socket at client
> side must be able to receive both udp response and icmp error
> messages(like host unreachable, port unreachable etc).
>
> Another approach is that, we will use two sockets for both source and
> destination, form source we will send udp probs(through udp socket)
> while at destination host, after receiving that prob(through udp
> socket), application will make an icmp packet and sent it back to the
> source host (using ICMP socket). And here at source host, that message
> and other icmp error messages will be received by icmp socket.
>
> But this approch dosen't look efficient to me, what u people say? If
> Any one has another approch plz let me know.
>
> Eagerly waiting for some +ve pings.