Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r230325

Wrap changes from svn r212126 inside LOADER_NFS_SUPPORT

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Modify pxe.c to use the version of nfs_getrootfh() that returns
the file handle's size and was recently committed to
lib/libstand/nfs.c. This allows pxeboot to use NFSv3 and work
correcty for non-FreeBSD as well as FreeBSD NFS servers.
If built with OLD_NFSV2 defined, the old
code that predated this patch will be used.

Tested by: danny at cs.huji.ac.il

If the pxe client is told to use / as the root path, honour that rather
of trying to mount /pxeroot instead.

PR: i386/106493
Submitted by: Andrey Russev
MFC after: 1 month

Do not attempt to make an NFS rpc call if using tftp

PR: kern/91720
Submitted by: Ruben Kerkhof

Pass the hostname we got from DHCP to the kernel so that machines can
share a read-only NFS root.

Allow kernels loaded by pxeboot, which was compiled with LOADER_TFTP_SUPPORT,
to stll be able to mount NFS root as prescribed by DCHP configuration. Since
pxeboot is using TFTP to get to the files, pxeboot can not rely on NFS to
provide it a root directory hande as a side effect. pxeboot has to make RPC
mount call itself.

Use __FBSDID().
Also some minor copyright style cleanups.

When looking for the ':' separator in the root path, don't go past
the terminating '\0'. Since the initialisation of rootpath in
libstand/bootp.c may copy junk into the rest of the buffer, it was
possible for the code to find a ':' after the '\0' and do the wrong
thing.

Reviewed by: ps
MFC after: 1 week

Don't set the gateway address if the netmask is zero or we're on
the same network. PXE does not do netmask calculations, so if the
gateway is set it will use it.

Submitted by: peter & FreeBSD cluster ACLs

Honor the ip address given in the root-path dhcp option.

PR: 21743
Submitted by: Brian Candler <B.Candler@pobox.com>

Export the salient configuration items in a non-pxe-specific namespace
to allow commonality between varying platforms. This is a step
towards parsing the diskless configuration information with MI code
inside the kernel.

Export the interface hardware address to the kernel, so that it is possible
to determine the boot interface with certainty.

Export the NFS filehandle for the root mount to the kernel, so that the
kernel does not need to perform a mount RPC call.

Add support to send the string 'PXEClient' as the Vendor class
identifier to the DHCP server. Now you can check for this string
in your dhcp configuration to decide whether you will hand out a
lease to the client or not.

Pass along the interesting variables we were given from DHCP so we
can utilize them in the kernel and with kenv.

Cleanup warnings. Most of these are signed/unsigned warnings, as well as
some added const's.

Wrap the failure warnings around PXE_DEBUG in the cleanup routine.
It does not matter if they fail, so dont print anything about it
unless we are debugging.

Fall back to /pxeroot as the location of the NFS exported directory
if we are not given one by dhcp.
Remove extra includes while I am here.

Reminded by: jlemon

Make PXE do a dhcp request to find out where its files are. The
DHCP server is no longer required to also act as the NFS/TFTP
server.

Don't report errors when we UDP_WRITE fails with a status of 1.

Bring support in for Intel Wired for Management 1.1 (PXE 0.99 and
below). This did not work previously because interrupts were
disabled when PXE calls were being made, and they must be enabled.
This should also allow us to be compliant with all newer PXE rom's
from Intel.

For PXE 0.99, this has been tested using the Intel N440BX motherboard
and I am confident it will work on the Intel L440GX motherboard.

Lots of help/information from: jhb, peter

I would like to thank Michael Johnston <michael.johnston@intel.com>,
Mike Henry <mike.henry@intel.com>, and all the other PXE developers
at Intel for their help, and information in helping solve this
problem.

Make the loader a little smarter about when it is and is not allowed
to call PXE.

Don't call the PXE cleanup routine if PXE is not enabled. This
should fix the "Invalid partition table" error people were seeing.

Add a cleanup function. This is needed for PXE where you should
shutdown the UNDI and unload the stack.

Use !PXE api over PXENV+ api.
Magic trampoline by: peter (at 4am and after a good whipping at airhockey)
Do a better job of returning and detecting errors.

Make PXE use the UDP API. This allows for both TFTP and NFS support.
You may specify TFTP or NFS via compile time options in the loader,
but not both at this time.

Also, remove a warning about not knowing how to boot from network
devices. We can obviously do that now.

Add all the PXE related structures from the 2.1 PXE spec from Intel.
Fix exsisting code to match the spec.

Mega i386 loader commit.
- Don't hard code 0x10000 as the entry point for the loader. Instead add
src/sys/boot/i386/Makefile.inc which defines a make variable with the
entry point for the loader. Move the loader's entry point up to
0x20000, which makes PXE happy.
- Don't try to use cpp to parse btxldr for the optional BTXLDR_VERBOSE,
instead use m4 to achieve this. Also, add a BTXLDR_VERBOSE knob in the
btxldr Makefile to turn this option on.
- Redo parts of cdldr's Makefile so that it now builds and installs cdboot
instead of having i386/loader/Makefile do that. Also, add in some more
variables to make the pxeldr Makefile almost identical and thus to ease
maintainability.
- Teach cdldr about the a.out format. Cdldr now parsers the a.out header
of the loader binary and relocates it based on that. The entry point of
the loader no longer has to be hardcoded into cdldr. Also, the boot
info table from mkisofs is no longer required to get a useful cdboot.
- Update the lsdev function for BIOS disks to parse other file systems
(such as DOS FAT) that we currently support. This is still buggy as
it assumes that a floppy with a DOS boot sector actually has a MBR and
parses it as such. I'll be fixing this in the future.
- The biggie: Add in support for booting off of PXE-enabled network
adapters. Currently, we use the TFTP API provided by the PXE BIOS.
Eventually we will switch to using the low-level NIC driver thus
allowing both TFTP and NFS to be used, but for now it's just TFTP.

Submitted by: ps, alfred
Testing by: Benno Rice <benno@netizen.com.au>