Avoid leaking I/O buffers in ib_destroy_qp() by completing any
outstanding work queue entries with a generic error code.  This
requires the completion handlers to be available to ib_destroy_qp(),
which is done by making them static configuration parameters of the CQ
(set by ib_create_cq()) rather than being provided on each call to
ib_poll_cq().

This mimics the functionality of netdev_{tx,rx}_flush().  The netdev
flush functions would previously have been catching any I/O buffers
leaked by the IPoIB data queue (though not by the IPoIB metadata
queue).

Add the simplified ne2k_isa driver.  It is just a selective copy+paste
of the relevant parts from ns8390.c plus a little trivial hacking to
make it actually work.

It is true that the code is pretty ugly, but:
  a) ns8390.c is worse
  b) It is only 372 lines and no #ifdefs
  c) It works both in qemu/bochs and in real hardware
     and we all know it is easier to cleanup working code

Hope someone will find the time to rewrite this driver properly,
but until then at least for me this is an ok solution.

Signed-off-by: Pantelis Koukousoulas <pktoss@gmail.com>

netdev_rx_err() and netdev_tx_complete_err() get passed the error
code, but currently use it only in debug messages.

Retain error numbers and frequencey counts for up to
NETDEV_MAX_UNIQUE_ERRORS (4) different errors for each of TX and RX.
This allows the "ifstat" command to report the reasons for TX/RX
errors in most cases, even in non-debug builds.

Settings can be constructed using a dotted-decimal notation, to allow
for access to unnamed settings.  The default interpretation is as a
DHCP option number (with encapsulated options represented as
"<encapsulating option>.<encapsulated option>".

In several contexts (e.g. SMBIOS, Phantom CLP), it is useful to
interpret the dotted-decimal notation as referring to non-DHCP
options.  In this case, it becomes necessary for these contexts to
ignore standard DHCP options, otherwise we end up trying to, for
example, retrieve the boot filename from SMBIOS.

Allow settings blocks to specify a "tag magic".  When dotted-decimal
notation is used to construct a setting, the tag magic value of the
originating settings block will be ORed in to the tag number.
Store/fetch methods can then check for the magic number before
interpreting arbitrarily-numbered settings.

This implementation is tested and working, but not currently tied in
to the EFI build.

EFI requires us to be able to specify the source address for
individual transmitted packets, and to be able to extract the
destination address on received packets.

Take advantage of this to rationalise the push() and pull() methods so
that push() takes a (dest,source,proto) tuple and pull() returns a
(dest,source,proto) tuple.

Multicast hashing is an ugly overlap between network and link layers.
EFI requires us to provide access to this functionality, so move it
out of ipv4.c and expose it as a method of the link layer.

Currently this length is set at device allocation time, and is never
changed.

We have EFI APIs for CPU I/O, PCI I/O, timers, console I/O, user
access and user memory allocation.

EFI executables are created using the vanilla GNU toolchain, with the
EXE header handcrafted in assembly and relocations generated by a
custom efilink utility.

The userptr_t is now the fundamental type that gets used for conversions.
For example, virt_to_phys() is implemented in terms of virt_to_user() and
user_to_phys().

We now have two implementations for the timer API: one using the
time-of-day counter at 40:70 and one using RDTSC.  Both make use of
timer2_udelay().

Using start==0 to indicate a stopped timer is dangerous, because 0 is a
valid value for the current tick counter.

-Wformat-nonliteral is not enabled by -Wall and needs to be explicitly
 specified.

Modified the few files that use nonliteral format strings to work with
this new setting in place.

Inspired by a patch from Carl Karsten <carl@personnelware.com> and an
identical patch from Rorschach <r0rschach@lavabit.com>.

The intention is to include near-verbatim copies of the EFI headers
required by gPXE.  This is achieved using the import.pl script in
src/include/gpxe/efi.

Note that import.pl will modify any #include lines in each imported
header to reflect its new location within the gPXE tree.  It will also
tidy up the file by removing carriage return characters and trailing
whitespace.

gcc defines the magic __WCHAR_TYPE__ macro, in order to convey
information about whether or not the user selected -fshort-wchar.

Some devices (e.g. the Atmel AT24C11) have no concept of a device
address; they respond to every device address and use this value as
the word address.  Some other devices use part of the device address
field to extend the word address field.

Generalise the i2c bit-bashing support to handle this by defining the
device address length and word address length as properties of an i2c
device.  The word address is assumed to overflow into the device
address field if the address used exceeds the width of the word
address field.

Also add a bus reset mechanism.  i2c chips don't usually have a reset
line, so rebooting the host will not clear any bizarre state that the
chip may be in.  We reset the bus by clocking SCL until we see SDA
high, at which point we know we can generate a start condition and
have it seen by all devices.  We then generate a stop condition to
leave the bus in a known state prior to use.

Finally, add some extra debugging messages to i2c_bit.c.

The usefulness of DBGLVL_IO is limited by the fact that many cards
require large numbers of uninteresting I/O reads/writes at device
probe time, typically when driving a bit-bashing I2C/SPI bus to read
the MAC address.

This patch adds the DBG_DISABLE() and DBG_ENABLE() macros, which can
be used to temporarily disable and re-enable selected debug levels.
Note that debug levels must still be enabled in the build in order to
function at all: you can't use DBG_ENABLE(DBGLVL_IO) in an object
built with DEBUG=object:1 and expect it to do anything.

Determine the network-layer packet type and fill it in for UNDI
clients.  This is required by some NBPs such as emBoot's winBoot/i.

This change requires refactoring the link-layer portions of the
gPXE netdevice API, so that it becomes possible to strip the
link-layer header without passing the packet up the network stack.

Allow for an arbitrary number of splits of the system memory map via
INT 15,e820.

Features of the new map-mangling algorithm include:

  Supports random access to e820 map entries.

  Requires only sequential access support from the underlying e820
  map, even if our caller uses random access.

  Empty regions will always be stripped.

  Always terminates with %ebx=0, even if the underlying map terminates
  with CF=1.

  Allows for an arbitrary number of hidden regions, with underlying
  regions split into as many subregions as necessary.

Total size increase to achieve this is 193 bytes.

New min_timeout and max_timeout fields in struct retry_timer allow
users of this timer to set their own desired minimum and maximum
timeouts, without being constrained to a single global minimum and
maximum. Users of the timer can still elect to use the default global
values by leaving the min_timeout and max_timeout fields as 0.

Allow initiator to verify target authentication using CHAP.

When we boot from a DHCP-supplied filename, we previously relied on
the fact that the current working URI is set to tftp://[next-server]/
in order to resolve the filename into a full tftp:// URI.  However,
this process will eliminate the distinction between filenames with and
without initial slashes:

 cwuri="tftp://10.0.0.1/" filename="vmlinuz"  => URI="tftp://10.0.0.1/vmlinuz"
 cwuri="tftp://10.0.0.1/" filename="/vmlinuz" => URI="tftp://10.0.0.1/vmlinuz"

This distinction is important for some TFTP servers.  We now
explicitly construct a string of the form

 "tftp://[next-server]/filename"

so that a filename with an initial slash will result in a URI
containing a double-slash, e.g.

 "tftp://10.0.0.1//vmlinuz"

The TFTP code always strips a single initial slash, and so ends up
presenting the correct path to the server.

URIs entered explicitly by users at the command line must include a
double slash if they want an initial slash presented to the TFTP
server:

  "kernel tftp://10.0.0.1/vmlinuz"  => filename="vmlinuz"
  "kernel tftp://10.0.0.1//vmlinuz" => filename="/vmlinuz"

In tg3_chip_reset(), the PCI_EXPRESS change is taken from the Linux
tg3 driver. I am not sure what exactly it does (it is not documented
in the Linux driver), but it is necessary for the NIC to work
correctly.

Add yet another ugly hack to iscsiboot.c, this time to allow the user to
inhibit the shutdown/removal of the iSCSI INT13 device (and the network
devices, since they are required for the iSCSI device to function).

On the plus side, the fact that shutdown() now takes flags to
differentiate between shutdown-for-exit and shutdown-for-boot means that
another ugly hack (to allow returning via the PXE stack on BIOSes that
have broken INT 18 calls) will be easier.

I feel dirty.

We can just treat all non-kernel images as initrds, which matches our
behaviour for multiboot kernels.  This allows us to eliminate initrd as
an image type, and treat the "initrd" command as just another synonym for
"imgfetch".

This commit implements GDB over UDP.  Using UDP is more complex than
serial and has required some restructuring.

The GDB stub is now built using one or both of GDBSERIAL and GDBUDP
config.h options.

To enter the debugger, execute the gPXE shell command:
gdbstub <transport> [<options>...]

Where <transport> is "serial" or "udp".  For "udp", the name of a
configured network device is required:
gdbstub udp net0

The GDB stub listens on UDP port 43770 by default.

Some drivers that still use the legacy-driver wrapper (tg3 in particular)
apparently do not specify their alignment constraints properly.  This
hack forces any __shared data to be maximally aligned.

Note that this provides only 16-byte alignment; it is not possible to
request alignment to any greater than 16 bytes using
__attribute__((aligned)), since the relocation code will preserve only 16
byte alignment (and operation under -DKEEP_IT_REAL cannot preserve more
that 16 byte alignment).

Idea proposed by Tim Hockin <thockin@google.com>

Allow for timers to be started with fixed timeouts.

Tested against the mini-slamd server located in contrib/mini-slamd
with a single client, on a lossy network.

UDP sockets can be used for multicast, at which point it becomes
plausible that we could receive packets that aren't destined for us
but that still match on a port number.