[interface] Provide the ability to shut down multiple interfaces
Shutting down (and optionally restarting) multiple interfaces is
fraught with problems if there are loops in the interface connectivity
(e.g. the HTTP content-decoded and transfer-decoded interfaces, which
will generally loop back to each other). Various workarounds
currently exist across the codebase, generally involving preceding
calls to intf_nullify() to avoid problems due to known loops.
Provide intfs_shutdown() and intfs_restart() to allow all of an
object's interfaces to be shut down (or restarted) in a single call,
without having to worry about potential external loops.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[interface] Unplug interface before calling intf_close() in intf_shutdown()
The call to intf_close() may result in the original interface being
reopened. For example: when reading the capacity of a 2TB+ disk via
iSCSI, the SCSI layer will respond to the intf_close() from the READ
CAPACITY (10) command by immediately issuing a READ CAPACITY (16)
command. The iSCSI layer happens to reuse the same interface for the
new command (since it allows only a single concurrent command).
Currently, intf_shutdown() unplugs the interface after the call to
intf_close() returns. In the above scenario, this results in
unplugging the just-reopened interface.
Fix by transferring the interface destination (and its reference) to a
temporary interface, and so effectively performing the unplug before
making the call to intf_close().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Reduce the cost of implementing object methods which convey no
information beyond the fact that the method has been called.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[interface] Default to calling intf_restart() in response to intf_close()
If an object interface does not provide an intf_close() method, then
default to calling intf_restart(). This allows static objects to
safely ignore intf_close(), without needing to add code solely to
ensure that the interface gets unplugged.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[interface] Allow for non-pass-through interface methods
xfer_vredirect() should not be allowed to propagate to a pass-through
interface. For example, when an HTTPS connection is opened, the
redirect message should cause the TLS layer to reopen the TCP socket,
rather than causing the HTTP layer to disconnect from the TLS layer.
Fix by allowing for non-pass-through interface methods, and setting
xfer_vredirect() to be one such method.
This is slightly ugly, in that it complicates the notion of an
interface method call by adding a "pass-through" / "non-pass-through"
piece of metadata. However, the only current user of xfer_vredirect()
is iscsi.c, which uses it only because we don't yet have an
ioctl()-style call for retrieving the underlying socket address.
The new interface infrastructure allows for such a call to be created,
at which time this sole user of xfer_vredirect() can be removed,
xfer_vredirect() can cease to be an interface method and become simply
a wrapper around xfer_vreopen(), and the concept of a non-pass-through
interface method can be reverted.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[interface] Expand object interface to allow for polymorphic interfaces
We have several types of object interface at present (data-xfer, job
control, name resolution), and there is some duplication of
functionality between them. For example, job_done(), job_kill() and
xfer_close() are almost isomorphic to each other.
This updated version of the object interface mechanism allows for each
interface to export an arbitrary list of supported operations.
Advantages include:
Operations methods now receive a pointer to the object, rather than
a pointer to the interface. This allows an object to, for example,
implement a single close() method that can handle close() operations
from any of its exposed interfaces.
The close() operation is implemented as a generic operation (rather
than having specific variants for data-xfer, job control, etc.).
This will allow functions such as monojob_wait() to be used to wait
for e.g. a name resolution to complete.
The amount of boilerplate code required in objects is reduced, not
least because it is no longer necessary to include per-interface
methods that simply use container_of() to derive a pointer to the
object and then tail-call to a common per-object method.
The cost of adding new operations is reduced; adding a new data-xfer
operation such as stat() no longer incurs the penalty of adding a
.stat member to the operations table of all existing data-xfer
interfaces.
The data-xfer, job control and name resolution interfaces have not yet
been updated to use the new interface mechanism, but the code will
still compile and run.
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>
Michael Brown