Some ProxyDHCP implementations seem to violate the PXE specification
by expecting the client to retain options from the ProxyDHCPOFFER
rather than issuing a separate ProxyDHCPREQUEST.

Work around such broken clients by retaining the ProxyDHCPOFFER
packet, and proceeding to a ProxyDHCPREQUEST only if the
ProxyDHCPOFFER does not already contain PXE options.

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

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

A recent patch series breaks compatibility with various common DHCP
implementations.

Revert "[dhcp] Don't consider invalid offers to be duplicates"
This reverts commit 905ea56753.

Revert "[dhcp] Honor PXEBS_SKIP option in discovery control"
This reverts commit 620b98ee4b.

Revert "[dhcp] Keep multiple DHCP offers received, and use them intelligently"
This reverts commit 5efc2fcb60.

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

Guarantee that a retry timer cannot go out of scope while the timer is
running, and provide a guarantee to the expiry callback that the timer
will remain in scope during the entire callback (similar to the
guarantee provided to interface methods).

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

iPXE has never supported SEEK_END; the usage of "whence" offers only
the options of SEEK_SET and SEEK_CUR and so is effectively a boolean
flag.  Further flags will be required to support additional metadata
required by the Fibre Channel network model, so repurpose the "whence"
field as a generic "flags" field.

xfer_seek() has always been used with SEEK_SET, so remove the "whence"
field altogether from its argument list.

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

Even with the noinline specifier added by commit 1a260f8, gcc may skip
calls to non-inlinable functions that it knows have no side
effects. This caused the get_cached_dhcpack() call in start_dhcp(),
the weak stub of which has no code in its body, to be removed,
preventing cached DHCP from working.

Fix by adding a __keepme macro to compiler.h expanding to asm(""), as
recommended by gcc's info page, and using it in the weak stub for
get_cached_dhcpack().

Reported-by: Aaron Brooks <aaron@brooks1.net>
Tested-by: Aaron Brooks <aaron@brooks1.net>
Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Remove data-xfer as an interface type, and replace data-xfer
interfaces with generic interfaces supporting the data-xfer methods.

Filter interfaces (as used by the TLS layer) are handled using the
generic pass-through interface capability.  A side-effect of this is
that deliver_raw() no longer exists as a data-xfer method.  (In
practice this doesn't lose any efficiency, since there are no
instances within the current codebase where xfer_deliver_raw() is used
to pass data to an interface supporting the deliver_raw() method.)

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

Remove name-resolution as an interface type, and replace
name-resolution interfaces with generic interfaces supporting the
resolv_done() method.

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

Remove job-control as an interface type, and replace job-control
interfaces with generic interfaces supporting the close() method.
(Both done() and kill() are absorbed into the function of close();
kill() is merely close(-ECANCELED).)

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

Standardise on using timer_init() to initialise an embedded retry
timer, to match the coding style used by other embedded objects.

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

Standardise on using ref_init() to initialise an embedded reference
count, to match the coding style used by other embedded objects.

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

Add preprocessor magic to the error definitions to enable every error
usage to be tracked.

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

See RFC 4578 for details.

Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

This fixes a regression in BOOTP support; since BOOTP requests often
have the `siaddr' field set to 0.0.0.0, they would be considered
duplicates of the first zeroed-out offer slot.

Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

This removes the need for inline safety wrappers, marginally reducing
the size penalty of weak functions, and works around an apparent
binutils bug that causes undefined weak symbols to not actually be
NULL when compiling with -fPIE (as EFI builds do).

A bug in versions of binutils prior to 2.16 (released in 2005) will
cause same-file weak definitions to not work with those
toolchains. Update the README to reflect our new dependency on
binutils >= 2.16.

Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

It is permissible for a DHCP packet containing PXE options to specify
only "discovery control", instead of the more typical boot menu +
prompt options. This is the strategy used by older versions of
dnsmasq; by specifying the discovery control as PXEBS_SKIP, they cause
vendor PXE ROMs to ignore boot server discovery and just use the
filename and next-server options in the initial (Proxy)DHCP packet.
Modify iPXE to accept this behavior, to be more compatible with the
Intel firmware.

Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Tested-by: Kyle Kienapfel <kyle@shadowmage.org>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain.  Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.

Also update README, LOG and COPYRIGHTS to remove obsolete information.

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

Instead of keeping only the best IP and PXE offers, store all of them,
and pick the best to use just before a request is sent. This allows
priority differentiation to work even when lower-priority offers
provide PXE options, and improves robustness at sites with broken PXE
servers intermingled with working ones: when a ProxyDHCP request times
out, instead of giving up, we try the next PXE offer we've received.
It also allows us to avoid breaking up combined IP+PXE offers, which
can be important with some firewall configurations. This behavior
matches that of most vendor PXE ROMs.

Store a reference to the DHCPOFFER packet in the offer structure, so
that when registering settings after a successful ACK we can register
the proxy PXE settings we originally received; this removes the need
for a nonstandard duplicate REQUEST/ACK to port 67 of proxy servers
like dnsmasq that provide PXE options in the OFFER.

Total cost: 450 bytes uncompressed.

Signed-off-by: Marty Connor <mdc@etherboot.org>

When a DHCP session is started (using autoboot or a command-line `dhcp
net0'), check whether the new setting use-cached (DHCP option 175.178)
is TRUE; if so, skip DHCP and rely on currently registered
settings. This lets one combine a static IP with autoboot.

Before checking the use-cached setting, call a weak
get_cached_dhcpack() hook that can be implemented by particular builds
of gPXE supporting some fashion of retrieving a cached DHCPACK packet.
If one is available, it is registered as an options source, and then
either that packet's option 175.178 or the user's prior manual
use-cached setting can allow skipping duplicate DHCP.

Using cached packets is not the default because DHCP servers are often
configured to give gPXE different options than they give a vendor PXE
client; in order to break the infinite loop of PXE chaining, one would
need to load a gPXE with an embedded image that does something more
than autoboot.

Signed-off-by: Marty Connor <mdc@etherboot.org>

There is no defined error code for aborting a request but 0 is commonly
used.  This patch switches the abort request error code from
TFTP_ERR_UNKNOWN_TID (5) to 0.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

pxenv_tftp_get_fsize is an API call that PXE clients can call to
obtain the size of a remote file. It is implemented by starting a TFTP
transfer with pxe_tftp_open, waiting for the response and then
stopping the transfer with pxe_tftp_close(). This leaves the session
hanging on the TFTP server and it will try to resend the packet
repeatedly (verified with tftpd-hpa) until it times out.

This patch adds a method "tftpsize" that will abort the transfer after
the first packet is received from the server. This will terminate the
session on the server and is the same behaviour as Intel's PXE ROM
exhibits.

Together with a qemu patch to handle the ERROR packet (submitted to
qemu's mailing list), this resolves a specific issue where booting
pxegrub with qemu's TFTP server would be slow or hang.

I've tested this against qemu's tftp server and against my normal boot
infrastructure (tftpd-hpa). Booting pxegrub and loading extra files
now produces a trace similar to Intel's PXE client and there are no
spurious retransmits from tftpd any more.

Signed-off-by: Thomas Horsten <thomas@horsten.com>
Signed-off-by: Milan Plzik <milan.plzik@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

The retry timer is used to retransmit TFTP packets lost on the network,
and to start a new connection.  There is an unnecessary delay while
waiting for name resolution because the timer period is fixed and cannot
be shortened when name resolution completes.  This patch keeps the timer
period at zero while name resolution takes place so that no time is lost
once before sending the first packet.

Reported-by: Thomas Horsten <thomas@horsten.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

This patch adds TFTP support for files larger than 65535 blocks by
wrapping the 16-bit block number.

Reported-by: Mark Johnson <johnson.nh@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

IBM's Tivoli Provisioning Manager for OS Deployment, when acting as a
ProxyDHCP server, sends an initial offer with a vendor class of "PXEClient"
and vendor-encapsulated options that have nothing to do with PXE. To
differentiate between this case and the case of a ProxyDHCP server that
sends all PXE options in its initial offer, modify gPXE to check for
the presence of an encapsulated PXE boot menu option (43.9) instead of
simply checking for the existence of any encapsulated options at all.
This is the same check used by the Intel vendor PXE ROM.

Signed-off-by: Marty Connor <mdc@etherboot.org>

The PXE standard provides examples of ProxyDHCP responses being encoded both
as type DHCPOFFER and DHCPACK, but currently we only accept DHCPACKs. Since
there are PXE servers in existence that respond to ProxyDHCPREQUESTs with
DHCPOFFERs, modify gPXE's ProxyDHCP pruning logic to treat both types of
responses equally.

Signed-off-by: Marty Connor <mdc@etherboot.org>

Apparently, the DHCP relay logic on a Nortel 470-48T layer 2 switch
cares about the order of DHCP options.  Specifically, it requires
that the DHCP message type option be the first option present in the
DHCP packet.  We achieve this by having this option appear first in
our dhcp_request_options_data array, which pre-populates DHCP
requests.

Signed-off-by: Marty Connor <mdc@etherboot.org>

Users can find the bus type and PCI IDs for a network interface with:

netX/busid

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>

The PXE type field is canonically little-endian, but the pxebs command
treats it as big-endian in converting the type number passed on the
command line to a field value to search against. Fix, to prevent the
necessity of incantations like "pxebs net0 1536" to select menu item #6.

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

For IPoIB, the chaddr field is too small (16 bytes) to contain the
20-byte IPoIB link-layer address.  RFC4390 mandates that we should
pass an empty chaddr field and rely on the DHCP client identifier
instead.  This has many problems, not least of which is that a client
identifier containing an IPoIB link-layer address is not very useful
from the point of view of creating DHCP reservations, since the QPN
component is assigned at runtime and may vary between boots.

Leave the DHCP client identifier as-is, to avoid breaking existing
setups as far as possible, but expose the real hardware address (the
port GUID) via the DHCP chaddr field, using the broadcast flag to
instruct the DHCP server not to use this chaddr value as a link-layer
address.

This makes it possible (at least with ISC dhcpd) to create DHCP
reservations using host declarations such as:

    host duckling {
        fixed-address 10.252.252.99;
        hardware unknown-32 00:02:c9:02:00:25:a1:b5;
    }

If the ProxyDHCPOFFER already includes PXE options (i.e. option 60 is
set to "PXEClient" and option 43 is present) then assume that the
ProxyDHCPREQUEST can be sent to port 67, rather than port 4011.  This
is a reasonable assumption, since in that case the ProxyDHCP server
has already demonstrated by responding to the DHCPDISCOVER that it is
listening on port 67.  (If the ProxyDHCP server were not listening on
port 67, then the standard DHCP server would have been configured to
respond with option 60 set to "PXEClient" but no option 43 present.)

The PXE specification is ambiguous on this point; the specified
behaviour covers only the cases in which option 43 is *not* present in
the ProxyDHCPOFFER.  In these cases, we will continue to send the
ProxyDHCPREQUEST to port 4011.

This change is required in order to allow us to interoperate with
dnsmasq, which listens only on port 67.  (dnsmasq relies on
unspecified behaviour of the Intel PXE stack, which it seems will
retain the ProxyDHCPOFFER as an options source and never issue a
ProxyDHCPREQUEST, thereby enabling dnsmasq to omit listening on port
4011.)

IBM Tivoli PXE Server 5.1.0.3 is reported to send trailing garbage
bytes at the end of the OACK packet, which causes gPXE to reject the
packet and abort the TFTP transfer.

Work around the problem by processing as much as possible of the OACK,
and treating name/value parsing errors as non-fatal.

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

We currently send all boot server discovery requests to port 4011.
Section 2.2.1 of the PXE spec states that boot server discovery
packets should be "sent broadcast (port 67), multicast (port 4011), or
unicast (port 4011)".  Adjust our behaviour so that any boot server
discovery packets that are sent to the broadcast address are directed
to port 67 rather than port 4011.

This is required for operation with dnsmasq as a PXE server, since
dnsmasq listens only on port 67, and relies upon this (specified)
behaviour.

This change may break some setups using the (itself very broken) Linux
PXE server from kano.org.uk.  This server will, in its default
configuration, listen only on port 4011.  It never constructs a boot
server list (PXE_BOOT_SERVERS, option 43.8), and uses the wrong
definitions for the discovery control bits (PXE_DISCOVERY_CONTROL,
option 43.6).  The upshot is that it will always instruct the client
to perform multicast and broadcast discovery only.  In setups lacking
a valid multicast route on the server side, this used to work because
gPXE would eventually give up on the (non-responsive) multicast
address and send a broadcast request to port 4011, which the Linux PXE
server would respond to.  Now that gPXE correctly sends this broadcast
request to port 67 instead, it is never seen by the Linux PXE server,
and the boot fails.  The fix is to either (a) set up a multicast route
correctly on the server side before starting the PXE server, or (b)
edit /etc/pxe.conf to contain the server's unicast address in the
"multicast_address" field (a hack that happens to work).

Suggested-by: Simon Kelley <simon@thekelleys.org.uk>

This prevents gPXE from wasting time attempting to contact a ProxyDHCP
server on port 4011 if the DHCP response already contains the relevant
PXE options.  This behaviour is hinted at (though not explicitly
specified) in the PXE spec, and seems to match what the Intel client
does.

Suggested-by: Simon Kelley <simon@thekelleys.org.uk>

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

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

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.

This change makes it possible to break the PXE-chaining infinite loop
even when restricted to a Windows DHCP server.

The documentation in xfer.h and xfer.c does not say that the metadata
parameter is optional in calls such as xfer_deliver_iob_meta() and the
deliver_iob() method.  However, some code in net/ is prepared to
accept a NULL pointer, and xfer_deliver_as_iob() passes a NULL pointer
directly to the deliver_iob() method.

Fix this mess of conflicting assumptions by making everything assume
that the metadata parameter is mandatory, and fixing
xfer_deliver_as_iob() to pass in a dummy metadata structure (as is
already done in xfer_deliver_iob()).

Various combinations of options 43.6, 43.7 and 43.8 dictate which
servers we send Boot Server Discovery requests to, and which servers
we should accept responses from.  Obey these options, and remove the
explicit specification of a single Boot Server from start_pxebs() and
dependent functions.

There are many functions that take ownership of the I/O buffer they
are passed as a parameter.  The caller should not retain a pointer to
the I/O buffer.  Use iob_disown() to automatically nullify the
caller's pointer, e.g.:

    xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );

This will ensure that iobuf is set to NULL for any code after the call
to xfer_deliver_iob().

iob_disown() is currently used only in places where it simplifies the
code, by avoiding an extra line explicitly setting the I/O buffer
pointer to NULL.  It should ideally be used with each call to any
function that takes ownership of an I/O buffer.  (The SSA
optimisations will ensure that use of iob_disown() gets optimised away
in cases where the caller makes no further use of the I/O buffer
pointer anyway.)

If gcc ever introduces an __attribute__((free)), indicating that use
of a function argument after a function call should generate a
warning, then we should use this to identify all applicable function
call sites, and add iob_disown() as necessary.

A TFTP DATA packet with a block number of zero (representing a
negative offset within the file) could potentially cause problems.
Fixed by explicitly rejecting such packets.

Identified by Stefan Hajnoczi <stefanha@gmail.com>.

The DHCP client code now implements only the mechanism of the DHCP and
PXE Boot Server protocols.  Boot Server Discovery can be initiated
manually using the "pxebs" command.  The menuing code is separated out
into a user-level function on a par with boot_root_path(), and is
entered in preference to a normal filename boot if the DHCP vendor
class is "PXEClient" and the PXE boot menu option exists.

Try to qualify relative names in the DNS resolver using the DHCP Domain
Name.  For example:

  DHCP Domain Name: etherboot.org
  (Relative) Name: www

yields:

  www.etherboot.org

Only names with no dots ('.') will be modified.  A name with one or more
dots is unchanged.

pxe_tftp.c assumes that the first seek on its data-transfer interface
represents the block size.  Apart from being an ugly hack, this will
also screw up file size calculation for files smaller than one block.

The proper solution would be to extend the data-transfer interface to
support the reporting of stat()-like data.  This is not going to
happen until the cost of adding interface methods is reduced (a fix I
have planned since June 2008).

In the meantime, abuse the xfer_window() method to return the block
size, since it is not being used for anything else and is vaguely
justifiable.

Astonishingly, having returned the incorrect TFTP blocksize via
PXENV_TFTP_OPEN for almost a year seems not to have affected any of
the test cases run during that time; this bug was found only when
someone tried running the heavily-patched version of pxegrub found in
OpenSolaris.

PXE dictates a mechanism for boot menuing, involving prompting the
user with a variable message, waiting for a predefined keypress,
displaying a boot menu, and waiting for a selection.

This breaks the currently desirable abstraction that DHCP is a process
that can happen in the background without any user interaction.

Remove the lazy assumption that ProxyDHCP == "DHCP with option 60 set
to PXEClient", and explicitly separate the notion of ProxyDHCP from
the notion of packets containing PXE options.

It is possible to configure a DHCP server to hand out PXE options
without a ProxyDHCP server present.  This requires setting option 60
to "PXEClient", which will cause gPXE to attempt ProxyDHCP.

We assume in several places that dhcp->proxydhcpack is set to the
DHCPACK packet containing option 60 set to "PXEClient".  When we
transition into ProxyDHCPREQUEST, set dhcp->proxydhcpack=dhcp->dhcpack
so that this assumption holds true.

We ought to rename several references to "proxydhcp" to something more
accurate, such as "pxedhcp".  Treating a single DHCP response as
potentially both DHCPOFFER and ProxyDHCPOFFER does make the code
smaller, but the variable names get confusing.

Pick out the first boot menu item from the boot menu (option 43.9) and
pass it to the boot server as the boot menu item (option 43.71).

Also improve DHCP debug messages to include more details of the
packets being transmitted.