[netdevice] Limit MTU by hardware maximum frame length
Separate out the concept of "hardware maximum supported frame length"
and "configured link MTU", and limit the latter according to the
former.
In networks where the DHCP-supplied link MTU is inconsistent with the
hardware or driver capabilities (e.g. a network using jumbo frames),
this will result in iPXE advertising a TCP MSS consistent with a size
that can actually be received.
Note that the term "MTU" is typically used to refer to the maximum
length excluding the link-layer headers; we adopt this usage.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide a settings applicator to modify netdev->max_pkt_len in
response to changes to the "mtu" setting (DHCP option 26).
Note that as with MAC address changes, drivers are permitted to
completely ignore any changes in the MTU value. The net result will
be that iPXE effectively uses the smaller of either the hardware
default MTU or the software configured MTU.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
It is possible for the preloaded UNDI device to end up with no
specified bus type, since it may not be recognised as either a PCI or
an ISAPnP device. This will result in a bus type value of zero, which
currently results in NULL being treated as a string pointer by
netdev_fetch_bustype().
Fix by returning ENOENT if an unknown bus type is specified.
Reported-by: Todd Stansell <todd@stansell.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Expose the network interface name (e.g. "net0") as a setting. This
allows a script to obtain the name of the most recently opened network
interface via ${netX/ifname}.
Signed-off-by: Andrew Widdersheim <amwiddersheim@gmail.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[settings] Explicitly separate the concept of a completed fetched setting
The fetch_setting() family of functions may currently modify the
definition of the specified setting (e.g. to add missing type
information). Clean up this interface by requiring callers to provide
an explicit buffer to contain the completed definition of the fetched
setting, if required.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Give tap devices a meaningful name, and avoid segmentation faults when
attempting to retrieve ${net0/bustype} by assigning a new bus type for
tap devices.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[settings] Clarify usage of the term "named setting"
There are currently two conflicting usages of the term "named setting"
within iPXE: one refers to predefined settings (such as show up in the
"config" UI), the other refers to settings identified by a name (such
as "net0.dhcp/ip").
Split these usages into the term "predefined setting" and "named
setting" to avoid ambiguity.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[settings] Make "netX" settings block function as a symbolic link
Add a facility for settings blocks to act as symbolic links to other
settings blocks, and reimplement the "netX" virtual settings block
using this facility.
The primary advantage of this approach is that unscoped settings such
as ${mac} and ${filename} will now reflect the settings obtained from
the most recently opened network device: in most cases, this will mean
the settings obtained from the most recent DHCP attempt. This should
improve conformance to the principle of least astonishment.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Create an explicit concept of "settings scope" and eliminate the magic
values used for numerical setting tags.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Improve the appearance of the "config" user interface by ensuring that
settings appear in some kind of logical order.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[settings] Formalise notion of setting applicability
Expose a function setting_applies() to allow a caller to determine
whether or not a particular setting is applicable to a particular
settings block.
Restrict DHCP-backed settings blocks to accepting only DHCP-based
settings.
Restrict network device settings blocks to accepting only DHCP-based
settings and network device-specific settings such as "mac".
Inspired-by: Glenn Brown <glenn@myri.com>
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>
[Settings] Remove assumption that all settings have DHCP tag values
Allow for settings to be described by something other than a DHCP option
tag if desirable. Currently used only for the MAC address setting.
Separate out fake DHCP packet creation code from dhcp.c to fakedhcp.c.
Remove notion of settings from dhcppkt.c.
Rationalise dhcp.c to use settings API only for final registration of the
DHCP options, rather than using {store,fetch}_setting throughout.
Add a configuration settings block for each net device. This will
provide the parent scope for settings applicable only to that network
device (e.g. non-volatile options stored on the NIC, options obtained via
DHCP, etc.).
Expose the MAC address as a setting.
Michael Brown