Re: remote kernel debugging over a network

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sat, Jun 05, 2010 at 01:33:04PM -0700, Bakul Shah wrote:
> > custom protocol built directly atop Ethernet (ie, not IP-based).
> 
> At a previous company (about 13 years back) this is what we
> did.  The details are hazy now but we didn't change the gdb
> remote protocol; we just emulated a serial link that
> sent/recvd these packets.

This is basically what the old IPKDB code does as well.  The only
real problem that ever prevented its use was that it very unfortunately
used a variant GDB-serial-debug protocol which mainline GDB stopped
speaking right at about the exact same time IPKDB was checked into our
tree!

Using IP gets you routability, which is a big win.  Using TCP gets you a
world of pain with retransmission, flow control, etc. which is a big
lose.

IPKDB used a custom MD5-based packet hash for "security".  I actually
think it would probably be very easy to support a single IPsec ESP
security association instead.  The hair with IPsec is all with key
negotiation.  Don't bother, and don't do some things like replay
protection, and ESP is a very simple, compact little shim layer on IP.

Thor