The GMA code was based upon the SMA code.  We can save space by making
the SMA simply an instance of the GMA.

Now that IPoIB has to deal with only one set of queues, the queue set
abstraction becomes merely an inconvenient wrapper.

Generalise out the multicast group membership record code from IPoIB.

Generalise out the path record lookup code from IPoIB.

Generalise the subnet management agent into a general management agent
capable of sending and responding to MADs, including support for
retransmissions as necessary.

Currently, all Infiniband users must create a process for polling
their completion queues (or rely on a regular hook such as
netdev_poll() in ipoib.c).

Move instead to a model whereby the Infiniband core maintains a single
process calling ib_poll_eq(), and polling the event queue triggers
polls of the applicable completion queues.  (At present, the
Infiniband core simply polls all of the device's completion queues.)
Polling a completion queue will now implicitly refill all attached
receive work queues; this is analogous to the way that netdev_poll()
implicitly refills the RX ring.

Infiniband users no longer need to create a process just to poll their
completion queues and refill their receive rings.

IPoIB and the SMA have separate constants for the packet size to be
used to I/O buffer allocations.  Merge these into the single
IB_MAX_PAYLOAD_SIZE constant.

(Various other points in the Infiniband stack have hard-coded
assumptions of a 2048-byte payload; we don't currently support
variable MTUs.)

IPoIB has a link-layer broadcast address that varies according to the
partition key.  We currently go through several contortions to pretend
that the link-layer address is a fixed constant; by making the
broadcast address a property of the network device rather than the
link-layer protocol it will be possible to simplify IPoIB's broadcast
handling.

Move the icky call to step() from aoe.c to ata.c; this takes it at
least one step further away from where it really doesn't belong.

Unfortunately, AoE has the ugly aoe_discover() mechanism which means
that we still have a step() loop in aoe.c for now; this needs to be
replaced at some future point.

Move the icky call to step() from iscsi.c to scsi.c; this takes it at
least one step further away from where it really doesn't belong.

The PXE debugging messages have remained pretty much unaltered since
Etherboot 5.4, and are now difficult to read in comparison to most of
the rest of gPXE.

Bring the pxe_undi debug messages up to normal gPXE standards.

Expand the NETDEV_LINK_UP bit into a link_rc status code field,
allowing specific reasons for link failure to be reported via
"ifstat".

Originally-authored-by: Joshua Oreman <oremanj@rwcr.net>

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

In order to construct outgoing link-layer frames or parse incoming
ones properly, some protocols (such as 802.11) need more state than is
available in the existing variables passed to the link-layer protocol
handlers. To remedy this, add struct net_device *netdev as the first
argument to each of these functions, so that more information can be
fetched from the link layer-private part of the network device.

Updated all three call sites (netdevice.c, efi_snp.c, pxe_undi.c) and
both implementations (ethernet.c, ipoib.c) of ll_protocol to use the
new argument.

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

The 93C66 is identical to the 93C56 in programming interface and
addressing, but twice as large in data storage (4096 bits). It's
used in some RTL8185 wireless cards.

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

gPXE responds to duplicated ACKs with an immediate retransmission,
which can lead to a sorceror's apprentice syndrome.  It also responds
to out-of-range (or old duplicate) ACKs with a RST, which can cause
valid connections to be dropped.

Fix the sorceror's apprentice syndrome by leaving the retransmission
timer running (and so inhibiting the immediate retransmission) when we
receive a potential duplicate ACK.  This seems to match the behaviour
of Linux observed via wireshark traces.

Fix the RST issue by sending RST only on out-of-range ACKs that occur
before the connection is fully established, as per RFC 793.

These problems were exposed during development of the 802.11 wireless
link layer; the 802.11 protocol has a failure mode that can easily
cause duplicated packets.  The fixes were tested in a controlled way
by faking large numbers of duplicated packets in the rtl8139 driver.

Originally-fixed-by: Joshua Oreman <oremanj@rwcr.net>

MAX_LL_HEADER_LEN is erroneously set to 6 rather than 14, resulting
in possible data corruption whenever we send an ARP packet.

Fix value and add a comment explaining why MAX_LL_ADDR_LEN is greater
than MAX_LL_HEADER_LEN.

Reported-by: Joshua Oreman <oremanj@rwcr.net>

Windows text editors such as Notepad tend to use CRLF line endings,
which breaks gPXE's signature detection for script images.  Since
scripts are usually very small, they end up falling back to being
detected as valid PXE executable images (since there are no signature
checks for PXE executables).  Executing text files as x86 machine code
tends not to work well.

Fix by allowing for any isspace() character to terminate the "#!gpxe"
signature, and by ensuring that CR characters get stripped during
command line parsing.

Suggested-by: Shao Miller <Shao.Miller@yrdsb.edu.on.ca>

Several SPI chips will respond to an SPI read command with a dummy
zero bit immediately prior to the first real data bit.  This can be
used to autodetect the address length, provided that the command
length and data length are already known, and that the MISO data line
is tied high.

Tested-by: Thomas Miletich <thomas.miletich@gmail.com>
Debugged-by: Thomas Miletich <thomas.miletich@gmail.com>

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

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

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

This provides a mechanism for using arbitrarily-named variables within
gPXE, using the existing syntax for settings.

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

For partly historical reasons, various files in the gPXE source tree
are licensed under different, though compatible, terms.  Most of the
code is licensed under GPLv2 with the "or later" clause, but there are
exceptions such as:

  The string.h file, which derives from Linux and is licensed as
  Public Domain.

  The EFI header files, which are taken from the EDK2 source tree and
  are licensed under BSD.

  The 3c90x driver, which has a custom GPL-like licence text.

Introduce a FILE_LICENCE() macro to make licensing more explicit.
This macro should be applied exactly once to each source (.c, .S or
.h) file.  It will cause a corresponding zero-sized common symbol to
be added to any .o files generated from that source file (and hence to
any final gPXE binaries generated from that source file).  Determining
the applicable licences to generated files can then be done using e.g.

  $ objdump -t bin/process.o | grep __licence
  00000000       O *COM*  00000001 .hidden __licence_gpl2_or_later

indicating that bin/process.o is covered entirely by the GPLv2
with the "or later" clause, or

  $ objdump -t bin/rtl8139.dsk.tmp | grep __licence
  00033e8c g     O .bss.textdata  00000000 .hidden __licence_gpl2_only
  00033e8c g     O .bss.textdata  00000000 .hidden __licence_gpl2_or_later
  00033e8c g     O .bss.textdata  00000000 .hidden __licence_public_domain

indicating that bin/rtl8139.dsk includes both code licensed under
GPLv2 (both with and without the "or later" clause) and code licensed
as Public Domain.

Determining the result of licence combinations is currently left as an
exercise for the reader.

Add SMBIOS asset tag as a named setting.

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

The Mac compiler treats "#pragma pack()" as gcc's "#pragma pack(pop)",
and so dies if the pragma pack stack is empty.  Adding a "#pragma
pack(1)" immediately beforehand is enough to keep the Mac compiler
happy.

The combination of "#pragma pack(1)", "#pragma pack()" won't actually
achieve anything on a Mac, but it will at least build.  (With gcc, the
"#pragma pack()" overrides any previous pragmas, so is still useful.)

Suggested-by: Joshua Oreman <oremanj@rwcr.net>

This is required in order to build on Mac OS X.

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

When handling a redirection event, we need to close the existing
connection before opening the new connection.

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

Eliminate the potential for mismatches between table names and the
table entry data type by incorporating the data type into the
definition of the table, rather than specifying it explicitly in each
table accessor method.

Intel's C compiler (icc) chokes on the zero-length arrays that we
currently use as part of the mechanism for accessing linker table
entries.  Abstract away the zero-length arrays, to make a port to icc
easier.

Introduce macros such as for_each_table_entry() to simplify the common
case of iterating over all entries in a linker table.

Represent table names as #defined string constants rather than
unquoted literals; this avoids visual confusion between table names
and C variable or type names, and also allows us to force a
compilation error in the event of incorrect table names.

Allow for settings blocks to be created on demand.  This allows for
constructions such as

  set defaults/filename http://bootserver/bootfile
  set defaults/priority 0xff
  dhcp net0
  chain ${filename}

which will boot from the DHCP-provided filename, or from
"http://bootserver/bootfile" if the DHCP server does not provide a
filename.

(Note that "priority" gets interpreted as a signed integer, so setting
"defaults/priority" to 0xff will cause the "defaults" settings block
to have an effective priority of -1.)

Having a default script containing

  #!gpxe
  autoboot

can cause problems when entering commands to load and start a kernel
manually; the default script image will still be present when the
kernel is started and so will be treated as an initrd.  It is possible
to work around this by typing "imgfree" before any other commands, but
this is counter-intuitive.

Fix by allowing the embedded image list to be empty (in which case we
just call autoboot()), and making this the default.

Reported by alkisg@gmail.com.

Avoid passing credentials in the iBFT that were available but not
required for login.  This works around a problem in the Microsoft
iSCSI initiator, which will refuse to initiate sessions if the CHAP
password is fewer than 12 characters, even if the target ends up not
asking for CHAP authentication.

Given any block cipher, a corresponding CBC mode of behaviour for the
cipher can be created using the CBC_CIPHER() macro.