[bzimage] Report exact initrd length via bzImage header

iPXE currently pads initrd images to a multiple of 4kB and inserts
zero padding between images, as required by some versions of the Linux
kernel.  The overall length reported via the ramdisk_size field in the
bzImage header includes this zero padding.

This causes problems when using memdisk to load a gzip-compressed disk
image.  memdisk treats the ramdisk_size field as containing the exact
length of the initrd image, and uses this length to locate the 8-byte
gzip footer.  This will generally cause memdisk to fail to decompress
the disk image.

Fix by reporting the exact length of the initrd image set, including
any padding inserted between images but excluding any padding added at
the end of the final image.

Reported-by: Levente LEVAI <levail@aviatronic.hu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[realtek] Include link status register details in debug messages

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[romprefix] Do not clobber stack segment when returning to BIOS

Commit c429bf0 ("[romprefix] Store boot bus:dev.fn address as autoboot
device location") introduced a regression by using register %cx to
temporarily hold the PCI bus:dev.fn address, despite the fact that %cx
was already being used to hold the stored BIOS stack segment.
Consequently, when returning to the BIOS after a failed or cancelled
boot attempt, iPXE would end up calling INT 18 with the stack segment
set equal to the PCI bus:dev.fn address.  Writing to essentially
random areas of memory tends to upset even the more robust BIOSes.

Fix by using register %ax to temporarily hold the PCI bus:dev.fn
address.

Reported-by: Anton D. Kachalov <mouse@yandex-team.ru>
Tested-by: Anton D. Kachalov <mouse@yandex-team.ru>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[netdevice] Mark devices as open before calling open() method

When opening a VLAN device, vlan_open() will call netdev_open() on the
trunk device.  This will result in a call to netdev_notify(), which
will cause vlan_notify() to call vlan_sync() on the original VLAN
device, which will see that the trunk device is now open but the VLAN
device apparently isn't (since it has not yet been flagged as open by
netdev_open()).  The upshot is a second attempt to open the VLAN
device, which will result in an erroneous second call to vlan_open().
This convoluted chain of events then terminates harmlessly since
vlan_open() calls netdev_open() on the trunk device, which just
returns immediately since the trunk device is by now flagged as being
already open.

Prevent this from happening by having netdev_open() flag the device as
open prior to calling the device's open() method, and reflagging it as
closed if the open() method fails.

Originally-fixed-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[tcp] Update window even if ACK does not acknowledge new data

iPXE currently ignores ACKs which do not acknowledge any new data.
(In particular, it does not stop the retransmission timer; this is
done to prevent an immediate retransmission if a duplicate ACK is
received while the transmit queue is non-empty.)

If a peer provides a window size of zero and later sends a duplicate
ACK to update the window size, this update will therefore be ignored
and iPXE will never be able to transmit data.

Fix by updating the window size even for ACKs which do not acknowledge
new data.

Reported-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[linux] Avoid starting currticks() from zero every time

iPXE uses currticks() (along with the MAC address(es) of any network
devices) to seed the (non-cryptographic) random number generator.  The
current implementation of linux_currticks() ensures that the first
call to currticks() will always return zero; this results in identical
random number sequences on each run of iPXE on a given machine.  This
can cause odd-looking behaviour due to e.g. the reuse of local TCP
port numbers.

Fix by effectively rounding down the start time recorded by
linux_currticks() to the nearest whole second; this makes it unlikely
that consecutive runs of iPXE will use the exact same RNG sequence.

(Note that none of this affects the cryptographic RNG, which uses
/dev/random as a source of entropy.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[http] Use a retry timer to trigger retried requests

Use a retry timer to allow for the possibility of deferring a retried
request.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[http] Automatically retry request on a 503 Service Unavailable

A web server may return a 503 Service Unavailable response along with
a Retry-After header to direct the client to retry the request at a
later time.

The Retry-After header may be a number of seconds, or a full HTTP
timestamp (e.g. "Fri, 7 Mar 2014 17:22:14 GMT").  We have no
reasonable way of parsing a full HTTP timestamp; if the server chooses
to use this format then we simply retry after a fixed 5-second delay.

As per RFC 2616, in the absence of a Retry-After header we treat a
status code of 503 Service Unavailable as being equivalent to 500
Internal Server Error, and immediately fail the request.

Requested-by: Suresh Sundriyal <ssundriy@vmware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[mii] Add mii_dump() to dump all MII registers

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[realtek] Dump all MII register contents when link status changes

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[monojob] Reset timeout when progress is made

Redefine the timeout parameter from "time since start of job" to "time
since progress was last made".  This does not affect any existing
behaviour, since all existing users of the timeout parameter do not
provide progress indication.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[image] Add "--timeout" parameter to image downloading commands

iPXE will detect timeout failures in several situations: network
link-up, DHCP, TCP connection attempts, unacknowledged TCP data, etc.
This does not cover all possible circumstances.  For example, if a
connection to a web server is successfully established and the web
server acknowledges the HTTP request but never sends any data in
response, then no timeout will be triggered.  There is no timeout
defined within the HTTP specifications, and the underlying TCP
connection will not generate a timeout since it has no way to know
that the HTTP layer is expecting to receive data from the server.

Add a "--timeout" parameter to "imgfetch", "chain", etc.  If no
progress is made (i.e. no data is downloaded) within the timeout
period, then the download will be aborted.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Allow for 64-bit EFI_STATUS codes

On a 64-bit build, EFI_STATUS codes are 64-bit quantities, with the
"error/warning" bit located in bit 63.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Allow driver to be unloaded

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Connect driver to devices as part of installation

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[console] Fix display of characters with top bit set

Inhibit implicit sign-padding of characters with the top bit set
(e.g. accented characters), which confuses the mucurses library by
colliding with the bits used to store character attributes and
colours.

Reported-by: Marc Delisle <Marc.Delisle@cegepsherbrooke.qc.ca>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[lotest] Allow loopback testing on shared networks

Allow for extraneous packets to be received during loopback testing,
and so permit loopback tests to be performed when ports are connected
to a switch (rather than requiring ports to be directly connected with
a loopback cable).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[netdevice] Notify upper-layer drivers when RX processing is (un)frozen

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Avoid accidentally calling main() twice

EFIRC() uses PLATFORM_TO_ERRNO(), which evaluates its argument twice
(and can't trivially use a braced-group expression or an inline
function to avoid this, since it gets used outside of function
context).

The expression "EFIRC(main())" will therefore end up calling main()
twice, which is not the intended behaviour.  Every other instance of
EFIRC() is of the simple form "EFIRC(rc)", so fix by converting this
instance to match.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Unload our own image before exiting UEFI application

Signed-off-by: Michael Brown <mcb30@ipxe.org>