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    SubjectRe: a problem with NETPOLL/KGDBoE
    On Wed, Dec 19, 2007 at 06:22:55PM +0200, Ramagudi Naziir wrote:
    > On 12/6/07, Matt Mackall <> wrote:
    > > netpoll will ignore incoming UDP -from- the wrong port/ip/mac, since
    > > it's otherwise bypassing the firewall layer.
    > ...
    > > I forget how to deal
    > > with the source address issue in connection with GDB, perhaps Jason
    > > will remind us.
    > I have checked it out.
    > Seems like there is absolutely no way to configure the source
    > port gdb uses for the udp connection. So one must invoke a
    > "target remote udp:ip:port" command, see what was the
    > chosen source port (tcpdump/netstat), and reconfigure kgdb on the target.
    > While this works, it is rather awkward.
    > Do you think there is/can be another way to solve this issue
    > (like allowing NETPOLL to listen to a wildcard udp source port) ?

    Here are the checks from net/core/netpoll.c:__netpoll_rx:

    if (np->local_ip && np->local_ip != ntohl(iph->daddr))
    goto out;
    if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
    goto out;
    if (np->local_port && np->local_port != ntohs(uh->dest))
    goto out;

    In other words, we DON'T check remote_port and we don't check the
    local_port, local_ip, or remote_ip if they're zero. Sorry for the
    earlier confusion.

    My hazy memory here is that my version of kgdboe took the first packet
    it got and set remote_port from it so that it could reply. Not sure
    whether that got copied as I can't seem to find the relevant bits in
    the latest -mm.

    Mathematics is the supreme nostalgia of our time.

     \ /
      Last update: 2007-12-19 18:31    [W:0.020 / U:0.160 seconds]
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