gPXE is not compliant with the HTTP/1.1 specification (RFC 2616),
since it lacks support for "Transfer-Encoding: chunked". gPXE is,
however, compliant with the HTTP/1.0 specification (RFC 1945), which
does not require "Transfer-Encoding: chunked" to be supported.
The only HTTP/1.1 feature that gPXE uses is the "Host:" header, but
servers universally accept that one from HTTP/1.0 clients as an
optional extension (it is obligatory for HTTP/1.1). gPXE does not,
for example, appear to support connection caching. Advertising as a
HTTP/1.0 client will typically make the server close the connection
immediately upon sending the last data, which is actually beneficial
if we aren't going to keep the connection alive anyway.
The PXE spec is (as usual) unclear on precisely when ProxyDHCPREQUESTs
should be issued. We adapt the following, slightly paranoid approach:
If an offer contains an IP address, then it is a normal DHCPOFFER.
If an offer contains an option #60 "PXEClient", then it is a
ProxyDHCPOFFER. Note that the same packet can be both a normal
DHCPOFFER and a ProxyDHCPOFFER.
After receiving the normal DHCPACK, if we have received a
ProxyDHCPOFFER, we unicast a ProxyDHCPREQUEST back to the ProxyDHCP
server on port 4011. If we time out waiting for a ProxyDHCPACK, we
treat this as a non-fatal error.
Change the PXE return code for EWOULDBLOCK from PXENV_STATUS_FAILURE
to PXENV_STATUS_TFTP_OPEN. This code is only used by the FILE_READ
PXEXT call, and is necessary to distinguish "error" from "no data" in
that call.
(The only other nonblocking call is UDP_READ, where the caller doesn't
care about the distinction, however, gPXE doesn't use EWOULDBLOCK
internally to represent this condition in that code.)
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 dedicated functions create_dhcpdiscover(), create_dhcpack() and
create_proxydhcpack() for use by external code such as the PXE preboot
code.
Register ProxyDHCP options under the global scope "proxydhcp".
Unregister previously-acquired DHCP and ProxyDHCP settings when DHCP
succeeds.
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.
Add the notion of the settings hierarchy, complete with
register/unregister routines.
Rename set->store and get->fetch to avoid naming conflicts with get/put
as used in reference counting.
Add the concept of an abstract configuration setting, comprising a (DHCP)
tag value and an associated byte sequence.
Add the concept of a settings namespace.
Add functions for extracting string, IPv4 address, and signed and
unsigned integer values from configuration settings (analogous to
dhcp_snprintf(), dhcp_ipv4_option(), etc.).
Update functions for parsing and formatting named/typed options to work
with new settings API.
Update NVO commands and config UI to use new settings API.
Timers are sometimes required before the call to initialise(), so we
cannot rely on initialise() to set up the timers before use.
Also fix a potential integer overflow issue in generic_currticks_udelay()
Add missing comments to timer code.
Lock system if no suitable timer source is found.
Fix initialisation order so that timers are initialised before code that
needs to use them.
Allow encapsulated options to be specified as e.g. "175.3". As a
side-effect, change the separator character for the type field from "." to
":"; for example, the IP address pseudo-option is now "175.3:ipv4".
Add parse and display routines for 16-bit and 32-bit integer configuration
settings.
Add parse and display routines for hex-string configuration settings.
Assume hex-string as a configuration setting type if no type is explicitly
specified.
show_setting() and related functions now return an "actual length" in the
style of snprintf(). This is to allow consumers to allocate buffers large
enough to hold the formatted setting.
