b1ba80f8fb
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>
77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/*
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* Copyright (C) 2009 Joshua Oreman <oremanj@rwcr.net>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <gpxe/dhcp.h>
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#include <gpxe/dhcppkt.h>
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#include <gpxe/netdevice.h>
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#include <gpxe/iobuf.h>
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#include <gpxe/uaccess.h>
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/** @file
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*
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* Cached DHCP packet handling
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*
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*/
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/**
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* Store cached DHCPACK packet
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*
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* @v data User pointer to cached DHCP packet data
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* @v len Length of cached DHCP packet data
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* @ret rc Return status code
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*
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* This function should be called by the architecture-specific
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* get_cached_dhcpack() handler.
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*/
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void store_cached_dhcpack ( userptr_t data, size_t len ) {
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struct dhcp_packet *dhcppkt;
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struct dhcphdr *dhcphdr;
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struct settings *parent;
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int rc;
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/* Create DHCP packet */
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dhcppkt = zalloc ( sizeof ( *dhcppkt ) + len );
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if ( ! dhcppkt )
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return;
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/* Fill in data for DHCP packet */
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dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( * dhcppkt ) );
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copy_from_user ( dhcphdr, data, 0, len );
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dhcppkt_init ( dhcppkt, dhcphdr, len );
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DBG_HD ( dhcppkt->options.data, dhcppkt->options.len );
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/* Register settings on the last opened network device.
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* This will have the effect of registering cached settings
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* with a network device when "dhcp netX" is performed for that
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* device, which is usually what we want.
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*/
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parent = netdev_settings ( last_opened_netdev() );
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if ( ( rc = register_settings ( &dhcppkt->settings, parent ) ) != 0 )
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DBG ( "DHCP could not register cached settings: %s\n",
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strerror ( rc ) );
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dhcppkt_put ( dhcppkt );
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DBG ( "DHCP registered cached settings\n" );
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}
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