[tcp] Gracefully close connections during shutdown
We currently do not wait for a received FIN before exiting to boot a
loaded OS. In the common case of booting from an HTTP server, this
means that the TCP connection is left consuming resources on the
server side: the server will retransmit the FIN several times before
giving up.
Fix by initiating a graceful close of all TCP connections and waiting
(for up to one second) for all connections to finish closing
gracefully (i.e. for the outgoing FIN to have been sent and ACKed, and
for the incoming FIN to have been received and ACKed at least once).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ipoib] Attempt to generate ARPs as needed to repopulate REMAC cache
The only way to map an eIPoIB MAC address (REMAC) to an IPoIB MAC
address is to intercept an incoming ARP request or reply.
If we do not have an REMAC cache entry for a particular destination
MAC address, then we cannot transmit the packet. This can arise in at
least two situations:
- An external program (e.g. a PXE NBP using the UNDI API) may attempt
to transmit to a destination MAC address that has been obtained by
some method other than ARP.
- Memory pressure may have caused REMAC cache entries to be
discarded. This is fairly likely on a busy network, since REMAC
cache entries are created for all received (broadcast) ARP
requests. (We can't sensibly avoid creating these cache entries,
since they are required in order to send an ARP reply, and when we
are being used via the UNDI API we may have no knowledge of which
IP addresses are "ours".)
Attempt to ameliorate the situation by generating a semi-spurious ARP
request whenever we find a missing REMAC cache entry. This will
hopefully trigger an ARP reply, which would then provide us with the
information required to populate the REMAC cache.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
If the link is blocked (e.g. due to a Spanning Tree Protocol port not
yet forwarding packets) then defer DHCP discovery until the link
becomes unblocked.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[stp] Add support for detecting Spanning Tree Protocol non-forwarding ports
A fairly common end-user problem is that the default configuration of
a switch may leave the port in a non-forwarding state for a
substantial length of time (tens of seconds) after link up. This can
cause iPXE to time out and give up attempting to boot.
We cannot force the switch to start forwarding packets sooner, since
any attempt to send a Spanning Tree Protocol bridge PDU may cause the
switch to disable our port (if the switch happens to have the Bridge
PDU Guard feature enabled for the port).
For non-ancient versions of the Spanning Tree Protocol, we can detect
whether or not the port is currently forwarding and use this to inform
the network device core that the link is currently blocked.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[netdevice] Add a generic concept of a "blocked link"
When Spanning Tree Protocol (STP) is used, there may be a substantial
delay (tens of seconds) from the time that the link goes up to the
time that the port starts forwarding packets.
Add a generic concept of a "blocked link" (i.e. a link which is up but
which is not expected to communicate successfully), and allow "ifstat"
to indicate when a link is blocked.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ethernet] Add minimal support for receiving LLC frames
In some Ethernet framing variants the two-byte protocol field is used
as a length, with the Ethernet header being followed by an IEEE 802.2
LLC header. The first two bytes of the LLC header are the DSAP and
SSAP.
If the received Ethernet packet appears to use this framing, then
interpret the two-byte DSAP and SSAP as being the network-layer
protocol. This allows support for receiving Spanning Tree Protocol
frames (which use an LLC header with {DSAP,SSAP}=0x4242) to be added
without requiring a full LLC protocol layer.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[tcp] Do not shrink window when discarding received packets
We currently shrink the TCP window permanently if we are ever forced
(by a low-memory condition) to discard a previously received TCP
packet. This behaviour was intended to reduce the number of
retransmissions in a lossy network, since lost packets might
potentially result in the entire window contents being retransmitted.
Since commit e0fc8fe ("[tcp] Implement support for TCP Selective
Acknowledgements (SACK)") the cost of lost packets has been reduced by
around one order of magnitude, and the reduction in the window size
(which affects the maximum throughput) is now the more significant
cost.
Remove the code which reduces the TCP maximum window size when a
received packet is discarded.
Reported-by: Wissam Shoukair <wissams@mellanox.com>
Tested-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[neighbour] Return success when deferring a packet
Deferral of a packet for neighbour discovery is not really an error.
If we fail to discover a neighbour then the failure will eventually be
reported by the call to neighbour_destroy() when any outstanding I/O
buffers are discarded.
The current behaviour breaks PXE booting on FreeBSD, which seems to
treat the error return from PXENV_UDP_WRITE as a fatal error and so
never proceeds to poll PXENV_UDP_READ (and hence never allows iPXE to
receive the ARP reply and send the deferred UDP packet).
Change neighbour_tx() to return success when deferring a packet. This
fixes interoperability with FreeBSD and removes transient neighbour
cache misses from the "ifstat" error output, while leaving genuine
neighbour discovery failures visible via "ifstat" (once neighbour
discovery times out, or the interface is closed).
Debugged-by: Wissam Shoukair <wissams@mellanox.com>
Tested-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[base16] Add buffer size parameter to base16_encode() and base16_decode()
The current API for Base16 (and Base64) encoding requires the caller
to always provide sufficient buffer space. This prevents the use of
the generic encoding/decoding functionality in some situations, such
as in formatting the hex setting types.
Implement a generic hex_encode() (based on the existing
format_hex_setting()), implement base16_encode() and base16_decode()
in terms of the more generic hex_encode() and hex_decode(), and update
all callers to provide the additional buffer length parameter.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This fixes "initialization discards 'const' qualifier from pointer
target type" warnings with GCC 5.1.0.
Signed-off-by: Christian Hesse <mail@eworm.de>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[tcp] Implement support for TCP Selective Acknowledgements (SACK)
The TCP Selective Acknowledgement option (specified in RFC2018)
provides a mechanism for the receiver to indicate packets that have
been received out of order (e.g. due to earlier dropped packets).
iPXE often operates in environments in which there is a high
probability of packet loss. For example, the legacy USB keyboard
emulation in some BIOSes involves polling the USB bus from within a
system management interrupt: this introduces an invisible delay of
around 500us which is long enough for around 40 full-length packets to
be dropped. Similarly, almost all 1Gbps USB2 devices will eventually
end up dropping packets because the USB2 bus does not provide enough
bandwidth to sustain a 1Gbps stream, and most devices will not provide
enough internal buffering to hold a full TCP window's worth of
received packets.
Add support for sending TCP Selective Acknowledgements. This provides
the sender with more detailed information about which packets have
been lost, and so allows for a more efficient retransmission strategy.
We include a SACK-permitted option in our SYN packet, since
experimentation shows that at least Linux peers will not include a
SACK-permitted option in the SYN-ACK packet if one was not present in
the initial SYN. (RFC2018 does not seem to mandate this behaviour,
but it is consistent with the approach taken in RFC1323.) We ignore
any received SACK options; this is safe to do since SACK is only ever
advisory and we never have to send non-trivial amounts of data.
Since our TCP receive queue is a candidate for cache discarding under
low memory conditions, we may end up discarding data that has been
reported as received via a SACK option. This is permitted by RFC2018.
We follow the stricture that SACK blocks must not report data which is
no longer held by the receiver: previously-reported blocks are
validated against the current receive queue before being included
within the current SACK block list.
Experiments in a qemu VM using forced packet drops (by setting
NETDEV_DISCARD_RATE to 32) show that implementing SACK improves
throughput by around 400%.
Experiments with a USB2 NIC (an SMSC7500) show that implementing SACK
improves throughput by around 700%, increasing the download rate from
35Mbps up to 250Mbps (which is approximately the usable bandwidth
limit for USB2).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Microsoft IIS supports only MD5-sess for Digest authentication.
Requested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[legal] Relicense files under GPL2_OR_LATER_OR_UBDL
Relicense files with kind permission from
Stefan Hajnoczi <stefanha@redhat.com>
alongside the contributors who have already granted such relicensing
permission.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At some point in the past few years, binutils became more aggressive
at removing unused symbols. To function as a symbol requirement, a
relocation record must now be in a section marked with @progbits and
must not be in a section which gets discarded during the link (either
via --gc-sections or via /DISCARD/).
Update REQUIRE_SYMBOL() to generate relocation records meeting these
criteria. To minimise the impact upon the final binary size, we use
existing symbols (specified via the REQUIRING_SYMBOL() macro) as the
relocation targets where possible. We use R_386_NONE or R_X86_64_NONE
relocation types to prevent any actual unwanted relocation taking
place. Where no suitable symbol exists for REQUIRING_SYMBOL() (such
as in config.c), the macro PROVIDE_REQUIRING_SYMBOL() can be used to
generate a one-byte-long symbol to act as the relocation target.
If there are versions of binutils for which this approach fails, then
the fallback will probably involve killing off REQUEST_SYMBOL(),
redefining REQUIRE_SYMBOL() to use the current definition of
REQUEST_SYMBOL(), and postprocessing the linked ELF file with
something along the lines of "nm -u | wc -l" to check that there are
no undefined symbols remaining.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[legal] Relicense files under GPL2_OR_LATER_OR_UBDL
These files cannot be automatically relicensed by util/relicense.pl
since they either contain unusual but trivial contributions (such as
the addition of __nonnull function attributes), or contain lines
dating back to the initial git revision (and so require manual
knowledge of the code's origin).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[dhcp] Extract timing parameters out to config/dhcp.h
iPXE uses DHCP timeouts loosely based on values recommended by the
specification, but often abbreviated to reduce timeouts for reliable
and/or simple network topologies. Extract the DHCP timing parameters
to config/dhcp.h and document them. The resulting default iPXE
behavior is exactly the same, but downstreams are now afforded the
opportunity to implement spec-compliant behavior via config file
overrides.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The implementation of inet_aton() has an unknown provenance. Rewrite
this code to avoid potential licensing uncertainty.
Also move the code from core/misc.c to its logical home in net/ipv4.c,
and add a few extra test cases.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[tftp] Explicitly abort connection whenever parent interface is closed
Fetching the TFTP file size is currently implemented via a custom
"tftpsize://" protocol hack. Generalise this approach to instead
close the TFTP connection whenever the parent data-transfer interface
is closed.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[rndis] Ignore start-of-day RNDIS_INDICATE_STATUS_MSG with status 0x40020006
Windows Server 2012 R2 generates an RNDIS_INDICATE_STATUS_MSG with a
status code of 0x4002006. This status code does not appear to be
documented anywhere within the sphere of human knowledge.
Explicitly ignore this status code in order to avoid unnecessarily
cluttering the display when RNDIS debugging is enabled.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[hyperv] Assume that VMBus xfer page ranges correspond to RNDIS messages
The (undocumented) VMBus protocol seems to allow for transfer
page-based packets where the data payload is split into an arbitrary
set of ranges within the transfer page set.
The RNDIS protocol includes a length field within the header of each
message, and it is known from observation that multiple RNDIS messages
can be concatenated into a single VMBus message.
iPXE currently assumes that the transfer page range boundaries are
entirely arbitrary, and uses the RNDIS header length to determine the
RNDIS message boundaries.
Windows Server 2012 R2 generates an RNDIS_INDICATE_STATUS_MSG for an
undocumented and unknown status code (0x40020006) with a malformed
RNDIS header length: the length does not cover the StatusBuffer
portion of the message. This causes iPXE to report a malformed RNDIS
message and to discard any further RNDIS messages within the same
VMBus message.
The Linux Hyper-V driver assumes that the transfer page range
boundaries correspond to RNDIS message boundaries, and so does not
notice the malformed length field in the RNDIS header.
Match the behaviour of the Linux Hyper-V driver: assume that the
transfer page range boundaries correspond to the RNDIS message
boundaries and ignore the RNDIS header length. This avoids triggering
the "malformed packet" error and also avoids unnecessary data copying:
since we now have one I/O buffer per RNDIS message, there is no longer
any need to use iob_split().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[rndis] Clear receive filter when closing the device
On Windows Server 2012 R2, closing and reopening the device will
sometimes result in a non-functional RX datapath. The root cause is
unknown. Clearing the receive filter before closing the device seems
to fix the problem.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The Hyper-V RNDIS implementation on Windows Server 2012 R2 requires
that we send an explicit RNDIS initialisation message in order to get
a working RX datapath.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
As of commit 03f0c23 ("[ipoib] Expose Ethernet-compatible eIPoIB
link-layer addresses and headers"), all link layers have used
addresses which fit within the DHCP chaddr field. The dhcp_chaddr()
function was therefore made obsolete by this commit, but was
accidentally left present (though unused) in the source code.
Remove the dhcp_chaddr() function and the only remaining use of it,
unnecessarily introduced in commit 08bcc0f ("[dhcp] Check for matching
chaddr in received DHCP packets").
Reported-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[dhcp] Check for matching chaddr in received DHCP packets
On large networks a DHCP XID collision is possible. Fix by explicitly
checking the chaddr in received DHCP packets.
Originally-fixed-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Reject network devices which appear to be duplicates of those already
available via a different underlying hardware device. On a Xen PV-HVM
system, this allows us to filter out the emulated PCI NICs (which
would otherwise appear alongside the netfront NICs).
Note that we cannot use the Xen facility to "unplug" the emulated PCI
NICs, since there is no guarantee that the OS we subsequently load
will have a native netfront driver.
We permit devices with the same MAC address if they are attached to
the same underlying hardware device (e.g. VLAN devices).
Inspired-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some switches do not allow an individual link (as defined in IEEE Std
802.3ad-2000 section 43.3.5) to work alone in a link aggregation group
as described in section 43.3.6. This is verified on Dell's
PowerConnect M6220, based on the Broadcom Strata XGS-IV chipset.
Set the LACP_STATE_AGGREGATABLE flag in the actor.state field to
announce link aggregation in the response LACPDU, which will have the
switch enable the link aggregation group and allow frames to pass.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[netdevice] Reset network device index when last device is unregistered
When functioning as an EFI driver, drivers can be disconnected and
reconnected multiple times (e.g. via the EFI shell "connect" command,
or by running an executable such as ipxe.efi which will temporarily
disconnect existing drivers).
Minimise surprise by resetting the network device index to zero
whenever the last device is unregistered. This is not foolproof, but
it does handle the common case of having all devices unregistered and
then reregistered in the original order.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[build] Expose build timestamp, build name, and product names
Expose the build timestamp (measured in seconds since the Epoch) and
the build name (e.g. "rtl8139.rom" or "ipxe.efi"), and provide the
product name and product short name in a single centralised location.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Parse the sense data to extract the reponse code, the sense key, the
additional sense code, and the additional sense code qualifier.
Originally-implemented-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ipv6] Avoid potentially copying from a NULL pointer in ipv6_tx()
If ipv6_tx() is called with a non-NULL network device, a NULL or
unspecified source address, and a destination address which does not
match any routing table entry, then it will attempt to copy the source
address from a NULL pointer.
I don't think that there is currently any code path which could
trigger this behaviour, but we should probably ensure that it can
never happen.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown