ipkdb(4) - NetBSD Manual Pages

IPKDB(4)                  NetBSD Programmer's Manual                  IPKDB(4)


NAME

     ipkdb - IP-based kernel debugger


SYNOPSYS

     options IPKDB
     options IPKDBSECURE
     options IPKDBKEY="\"IPKDB key for remote debugging\""
     options IPKDB_NE_PCISLOT=x


DESCRIPTION

     ipkdb is a kernel debugger that uses UDP and IP to communicate with a re-
     mote debugger (normally gdb(1)).

     Since the debugger uses its own driver to talk to the networking hard-
     ware, the number of supported network interfaces is a lot less than what
     is supported by the kernel.  At the time of this writing, there is only
     support for a NE2000 compatible card in a PCI slot.  In order for ipkdb
     to find your card, you need to specify the slot the card is in via the
     options IPKDB_NE_PCISLOT.

     To use ipkdb, you have to setup a DHCP server, from which ipkdb can get
     the IP address for the interface that is used for debugging.

     To enter ipkdb, the remote debugger has to send the protocol start pack-
     et.  E.g., gdb will do this on the command
           target ipkdb debuggee IPKDB key for remote debugging
     where debuggee is the name of the machine to debug (which must resolve to
     the IP address of the interface), and the rest of the line corresponds to
     the definition of IPKDBKEY (see below).  For ipkdb to actually see this
     packet, the interface which is used for debugging has to be setup to ac-
     tually receive packets, i.e. it has to be up and running.

     To prevent messing around with a secured system, ipkdb normally also
     checks the security level at which the kernel is running.  ipkdb will on-
     ly work with security levels less than 1, unless the kernel is configured
     with options IPKDBSECURE.

     In addition, the debugger is forcedly entered on a panic, as well as on
     intial startup, if you boot the kernel with the -d option (note that this
     however is machine dependent).  On such a forced enter to ipkdb there is
     no need for the interface in question to already be up and running, since
     ipkdb only needs to send/receive packets via its own driver.

     As some form of security against the occasional hacker, ipkdb uses the
     definition of options IPKDBKEY to compute a checksum on the data in every
     packet.  The remote debugger has to send this checksum, based on the data
     it sends and the key, or ipkdb ignores the packet.  This is also used in
     order to check against data errors on the connection.


BUGS

     Since the kernel includes the definition of IPKDBKEY, anyone who can read
     the kernel can extract it and use it to enter ipkdb.

     There is no support for ip6(4).


SEE ALSO

     gdb(1), ddb(4), ip(4), udp(4), init(8)


HISTORY

     ipkdb appeared in NetBSD 1.3 for the first time.  It's configuration and
     setup changed quite a bit in NetBSD 1.5.

NetBSD 1.5                      March 27, 2000                               1