gpxe: delete long since obsolete snapshot of gPXE

gPXE has been deprecated in favor of iPXE for many, many years now.
It is much better than users get it directly from the iPXE project,
since we should no longer need any special modifications for Syslinux
use.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 0 insertions, 1587 deletions

diff --git a/gpxe/src/net/udp/dhcp.c b/gpxe/src/net/udp/dhcp.c
deleted file mode 100644
index ce2c8207..00000000
--- a/gpxe/src/net/udp/dhcp.c
+++ /dev/null
@@ -1,1587 +0,0 @@
-/*
- * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-FILE_LICENCE ( GPL2_OR_LATER );
-
-#include <string.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <ctype.h>
-#include <errno.h>
-#include <assert.h>
-#include <byteswap.h>
-#include <gpxe/if_ether.h>
-#include <gpxe/netdevice.h>
-#include <gpxe/device.h>
-#include <gpxe/xfer.h>
-#include <gpxe/open.h>
-#include <gpxe/job.h>
-#include <gpxe/retry.h>
-#include <gpxe/tcpip.h>
-#include <gpxe/ip.h>
-#include <gpxe/uuid.h>
-#include <gpxe/timer.h>
-#include <gpxe/settings.h>
-#include <gpxe/dhcp.h>
-#include <gpxe/dhcpopts.h>
-#include <gpxe/dhcppkt.h>
-#include <gpxe/features.h>
-
-/** @file
- *
- * Dynamic Host Configuration Protocol
- *
- */
-
-struct dhcp_session;
-static int dhcp_tx ( struct dhcp_session *dhcp );
-
-/**
- * DHCP operation types
- *
- * This table maps from DHCP message types (i.e. values of the @c
- * DHCP_MESSAGE_TYPE option) to values of the "op" field within a DHCP
- * packet.
- */
-static const uint8_t dhcp_op[] = {
-	[DHCPDISCOVER]	= BOOTP_REQUEST,
-	[DHCPOFFER]	= BOOTP_REPLY,
-	[DHCPREQUEST]	= BOOTP_REQUEST,
-	[DHCPDECLINE]	= BOOTP_REQUEST,
-	[DHCPACK]	= BOOTP_REPLY,
-	[DHCPNAK]	= BOOTP_REPLY,
-	[DHCPRELEASE]	= BOOTP_REQUEST,
-	[DHCPINFORM]	= BOOTP_REQUEST,
-};
-
-/** Raw option data for options common to all DHCP requests */
-static uint8_t dhcp_request_options_data[] = {
-	DHCP_MESSAGE_TYPE, DHCP_BYTE ( 0 ),
-	DHCP_MAX_MESSAGE_SIZE,
-	DHCP_WORD ( ETH_MAX_MTU - 20 /* IP header */ - 8 /* UDP header */ ),
-	DHCP_CLIENT_ARCHITECTURE, DHCP_WORD ( 0 ),
-	DHCP_CLIENT_NDI, DHCP_OPTION ( 1 /* UNDI */ , 2, 1 /* v2.1 */ ),
-	DHCP_VENDOR_CLASS_ID,
-	DHCP_STRING (  'P', 'X', 'E', 'C', 'l', 'i', 'e', 'n', 't', ':',
-		       'A', 'r', 'c', 'h', ':', '0', '0', '0', '0', '0', ':',
-		       'U', 'N', 'D', 'I', ':', '0', '0', '2', '0', '0', '1' ),
-	DHCP_USER_CLASS_ID,
-	DHCP_STRING ( 'g', 'P', 'X', 'E' ),
-	DHCP_PARAMETER_REQUEST_LIST,
-	DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_DNS_SERVERS,
-		      DHCP_LOG_SERVERS, DHCP_HOST_NAME, DHCP_DOMAIN_NAME,
-		      DHCP_ROOT_PATH, DHCP_VENDOR_ENCAP, DHCP_VENDOR_CLASS_ID,
-		      DHCP_TFTP_SERVER_NAME, DHCP_BOOTFILE_NAME,
-		      DHCP_EB_ENCAP, DHCP_ISCSI_INITIATOR_IQN ),
-	DHCP_END
-};
-
-/** Version number feature */
-FEATURE_VERSION ( VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH );
-
-/** DHCP server address setting */
-struct setting dhcp_server_setting __setting = {
-	.name = "dhcp-server",
-	.description = "DHCP server address",
-	.tag = DHCP_SERVER_IDENTIFIER,
-	.type = &setting_type_ipv4,
-};
-
-/** DHCP user class setting */
-struct setting user_class_setting __setting = {
-	.name = "user-class",
-	.description = "User class identifier",
-	.tag = DHCP_USER_CLASS_ID,
-	.type = &setting_type_string,
-};
-
-/** Use cached network settings */
-struct setting use_cached_setting __setting = {
-	.name = "use-cached",
-	.description = "Use cached network settings",
-	.tag = DHCP_EB_USE_CACHED,
-	.type = &setting_type_uint8,
-};
-
-/**
- * Name a DHCP packet type
- *
- * @v msgtype		DHCP message type
- * @ret string		DHCP mesasge type name
- */
-static inline const char * dhcp_msgtype_name ( unsigned int msgtype ) {
-	switch ( msgtype ) {
-	case DHCPNONE:		return "BOOTP"; /* Non-DHCP packet */
-	case DHCPDISCOVER:	return "DHCPDISCOVER";
-	case DHCPOFFER:		return "DHCPOFFER";
-	case DHCPREQUEST:	return "DHCPREQUEST";
-	case DHCPDECLINE:	return "DHCPDECLINE";
-	case DHCPACK:		return "DHCPACK";
-	case DHCPNAK:		return "DHCPNAK";
-	case DHCPRELEASE:	return "DHCPRELEASE";
-	case DHCPINFORM:	return "DHCPINFORM";
-	default:		return "DHCP<invalid>";
-	}
-}
-
-/**
- * Calculate DHCP transaction ID for a network device
- *
- * @v netdev		Network device
- * @ret xid		DHCP XID
- *
- * Extract the least significant bits of the hardware address for use
- * as the transaction ID.
- */
-static uint32_t dhcp_xid ( struct net_device *netdev ) {
-	uint32_t xid;
-
-	memcpy ( &xid, ( netdev->ll_addr + netdev->ll_protocol->ll_addr_len
-			 - sizeof ( xid ) ), sizeof ( xid ) );
-	return xid;
-}
-
-/****************************************************************************
- *
- * DHCP session
- *
- */
-
-struct dhcp_session;
-
-/** DHCP session state operations */
-struct dhcp_session_state {
-	/** State name */
-	const char *name;
-	/**
-	 * Construct transmitted packet
-	 *
-	 * @v dhcp		DHCP session
-	 * @v dhcppkt		DHCP packet
-	 * @v peer		Destination address
-	 */
-	int ( * tx ) ( struct dhcp_session *dhcp,
-		       struct dhcp_packet *dhcppkt,
-		       struct sockaddr_in *peer );
-	/** Handle received packet
-	 *
-	 * @v dhcp		DHCP session
-	 * @v dhcppkt		DHCP packet
-	 * @v peer		DHCP server address
-	 * @v msgtype		DHCP message type
-	 * @v server_id		DHCP server ID
-	 */
-	void ( * rx ) ( struct dhcp_session *dhcp,
-			struct dhcp_packet *dhcppkt,
-			struct sockaddr_in *peer,
-			uint8_t msgtype, struct in_addr server_id );
-	/** Handle timer expiry
-	 *
-	 * @v dhcp		DHCP session
-	 */
-	void ( * expired ) ( struct dhcp_session *dhcp );
-	/** Transmitted message type */
-	uint8_t tx_msgtype;
-	/** Apply minimum timeout */
-	uint8_t apply_min_timeout;
-};
-
-static struct dhcp_session_state dhcp_state_discover;
-static struct dhcp_session_state dhcp_state_request;
-static struct dhcp_session_state dhcp_state_proxy;
-static struct dhcp_session_state dhcp_state_pxebs;
-
-/** DHCP offer is valid for IP lease */
-#define DHCP_OFFER_IP	1
-
-/** DHCP offer is valid for PXE options */
-#define DHCP_OFFER_PXE	2
-
-/** A DHCP offer */
-struct dhcp_offer {
-	/** IP address of server granting offer */
-	struct in_addr server;
-
-	/** IP address being offered, or 0.0.0.0 for a pure proxy */
-	struct in_addr ip;
-
-	/** DHCP packet containing PXE options; NULL if missing or proxied */
-	struct dhcp_packet *pxe;
-
-	/** Valid uses for this offer, a combination of DHCP_OFFER bits */
-	uint8_t valid;
-
-	/** Priority of this offer */
-	int8_t priority;
-
-	/** Whether to ignore PXE DHCP extensions */
-	uint8_t no_pxedhcp;
-};
-
-/** Maximum number of DHCP offers to queue */
-#define DHCP_MAX_OFFERS   6
-
-/** A DHCP session */
-struct dhcp_session {
-	/** Reference counter */
-	struct refcnt refcnt;
-	/** Job control interface */
-	struct job_interface job;
-	/** Data transfer interface */
-	struct xfer_interface xfer;
-
-	/** Network device being configured */
-	struct net_device *netdev;
-	/** Local socket address */
-	struct sockaddr_in local;
-	/** State of the session */
-	struct dhcp_session_state *state;
-
-	/** PXE Boot Server type */
-	uint16_t pxe_type;
-	/** List of PXE Boot Servers to attempt */
-	struct in_addr *pxe_attempt;
-	/** List of PXE Boot Servers to accept */
-	struct in_addr *pxe_accept;
-
-	/** Retransmission timer */
-	struct retry_timer timer;
-	/** Start time of the current state (in ticks) */
-	unsigned long start;
-
-	/** DHCP offer just requested */
-	struct dhcp_offer *current_offer;
-	/** List of DHCP offers received */
-	struct dhcp_offer offers[DHCP_MAX_OFFERS];
-};
-
-/**
- * Free DHCP session
- *
- * @v refcnt		Reference counter
- */
-static void dhcp_free ( struct refcnt *refcnt ) {
-	struct dhcp_session *dhcp =
-		container_of ( refcnt, struct dhcp_session, refcnt );
-	int i;
-
-	for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) {
-		if ( dhcp->offers[i].pxe )
-			dhcppkt_put ( dhcp->offers[i].pxe );
-	}
-
-	netdev_put ( dhcp->netdev );
-	free ( dhcp );
-}
-
-/**
- * Mark DHCP session as complete
- *
- * @v dhcp		DHCP session
- * @v rc		Return status code
- */
-static void dhcp_finished ( struct dhcp_session *dhcp, int rc ) {
-
-	/* Block futher incoming messages */
-	job_nullify ( &dhcp->job );
-	xfer_nullify ( &dhcp->xfer );
-
-	/* Stop retry timer */
-	stop_timer ( &dhcp->timer );
-
-	/* Free resources and close interfaces */
-	xfer_close ( &dhcp->xfer, rc );
-	job_done ( &dhcp->job, rc );
-}
-
-/**
- * Transition to new DHCP session state
- *
- * @v dhcp		DHCP session
- * @v state		New session state
- */
-static void dhcp_set_state ( struct dhcp_session *dhcp,
-			     struct dhcp_session_state *state ) {
-
-	DBGC ( dhcp, "DHCP %p entering %s state\n", dhcp, state->name );
-	dhcp->state = state;
-	dhcp->start = currticks();
-	stop_timer ( &dhcp->timer );
-	dhcp->timer.min_timeout =
-		( state->apply_min_timeout ? DHCP_MIN_TIMEOUT : 0 );
-	dhcp->timer.max_timeout = DHCP_MAX_TIMEOUT;
-	start_timer_nodelay ( &dhcp->timer );
-}
-
-/**
- * Determine next DHCP offer to try
- *
- * @v dhcp		DHCP session
- * @v type		DHCP offer type
- * @ret offer		Next DHCP offer to try
- *
- * Offers are ranked by priority, then by completeness (combined
- * IP+PXE are tried before @a type alone), then by order of receipt.
- */
-static struct dhcp_offer * dhcp_next_offer ( struct dhcp_session *dhcp,
-					     uint8_t type ) {
-
-	struct dhcp_offer *offer;
-	struct dhcp_offer *best = NULL;
-
-	for ( offer = dhcp->offers ; offer < dhcp->offers + DHCP_MAX_OFFERS ;
-	      offer++ ) {
-		if ( ( offer->valid & type ) &&
-		     ( ( best == NULL ) ||
-		       ( offer->priority > best->priority ) ||
-		       ( ( offer->priority == best->priority ) &&
-			 ( offer->valid & ~best->valid ) ) ) )
-			best = offer;
-	}
-
-	return best;
-}
-
-/****************************************************************************
- *
- * DHCP state machine
- *
- */
-
-/**
- * Construct transmitted packet for DHCP discovery
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		Destination address
- */
-static int dhcp_discovery_tx ( struct dhcp_session *dhcp,
-			       struct dhcp_packet *dhcppkt __unused,
-			       struct sockaddr_in *peer ) {
-
-	DBGC ( dhcp, "DHCP %p DHCPDISCOVER\n", dhcp );
-
-	/* Set server address */
-	peer->sin_addr.s_addr = INADDR_BROADCAST;
-	peer->sin_port = htons ( BOOTPS_PORT );
-
-	return 0;
-}
-
-/**
- * Handle received DHCPOFFER during any state
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		DHCP server address
- * @v msgtype		DHCP message type
- * @v server_id		DHCP server ID
- */
-static void dhcp_rx_offer ( struct dhcp_session *dhcp,
-			    struct dhcp_packet *dhcppkt,
-			    struct sockaddr_in *peer, uint8_t msgtype,
-			    struct in_addr server_id ) {
-	char vci[9]; /* "PXEClient" */
-	int vci_len;
-	int has_pxeclient;
-	int pxeopts_len;
-	int has_pxeopts;
-	struct dhcp_offer *offer;
-	int i;
-
-	DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
-	       dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
-	       ntohs ( peer->sin_port ) );
-	if ( server_id.s_addr != peer->sin_addr.s_addr )
-		DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
-
-	/* Identify offered IP address */
-	if ( dhcppkt->dhcphdr->yiaddr.s_addr )
-		DBGC ( dhcp, " for %s", inet_ntoa ( dhcppkt->dhcphdr->yiaddr ));
-
-	/* Enqueue an offer to be filled in */
-	for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) {
-		if ( dhcp->offers[i].server.s_addr == server_id.s_addr ) {
-			DBGC ( dhcp, " dup\n" );
-			return;
-		}
-
-		if ( ! dhcp->offers[i].valid )
-			break;
-	}
-	if ( i == DHCP_MAX_OFFERS ) {
-		DBGC ( dhcp, " dropped\n" );
-		return;
-	}
-
-	offer = &dhcp->offers[i];
-	offer->server = server_id;
-	offer->ip = dhcppkt->dhcphdr->yiaddr;
-
-	/* Identify "PXEClient" vendor class */
-	vci_len = dhcppkt_fetch ( dhcppkt, DHCP_VENDOR_CLASS_ID,
-				  vci, sizeof ( vci ) );
-	has_pxeclient = ( ( vci_len >= ( int ) sizeof ( vci ) ) &&
-			  ( strncmp ( "PXEClient", vci, sizeof (vci) ) == 0 ));
-
-	/* Identify presence of PXE-specific options */
-	pxeopts_len = dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU, NULL, 0 );
-	has_pxeopts = ( pxeopts_len >= 0 );
-	if ( has_pxeclient )
-		DBGC ( dhcp, "%s", ( has_pxeopts ? " pxe" : " proxy" ) );
-
-	if ( has_pxeclient && has_pxeopts ) {
-		/* Save reference to packet for future use */
-		if ( offer->pxe )
-			dhcppkt_put ( offer->pxe );
-		offer->pxe = dhcppkt_get ( dhcppkt );
-	}
-
-	/* Identify priority */
-	dhcppkt_fetch ( dhcppkt, DHCP_EB_PRIORITY, &offer->priority,
-			sizeof ( offer->priority ) );
-	if ( offer->priority )
-		DBGC ( dhcp, " pri %d", offer->priority );
-
-	/* Identify ignore-PXE flag */
-	dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &offer->no_pxedhcp,
-			sizeof ( offer->no_pxedhcp ) );
-	if ( offer->no_pxedhcp )
-		DBGC ( dhcp, " nopxe" );
-	DBGC ( dhcp, "\n" );
-
-	/* Determine roles this offer can fill */
-	if ( offer->ip.s_addr &&
-	     ( peer->sin_port == htons ( BOOTPS_PORT ) ) &&
-	     ( ( msgtype == DHCPOFFER ) || ( ! msgtype /* BOOTP */ ) ) )
-		offer->valid |= DHCP_OFFER_IP;
-
-	if ( has_pxeclient && ( msgtype == DHCPOFFER ) )
-		offer->valid |= DHCP_OFFER_PXE;
-}
-
-/**
- * Handle received packet during DHCP discovery
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		DHCP server address
- * @v msgtype		DHCP message type
- * @v server_id		DHCP server ID
- */
-static void dhcp_discovery_rx ( struct dhcp_session *dhcp,
-				struct dhcp_packet *dhcppkt,
-				struct sockaddr_in *peer, uint8_t msgtype,
-				struct in_addr server_id ) {
-	unsigned long elapsed;
-	struct dhcp_offer *ip_offer;
-
-	dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
-
-	/* We can exit the discovery state when we have a valid
-	 * DHCPOFFER, and either:
-	 *
-	 *  o  The DHCPOFFER instructs us to ignore ProxyDHCPOFFERs, or
-	 *  o  We have a valid ProxyDHCPOFFER, or
-	 *  o  We have allowed sufficient time for ProxyDHCPOFFERs.
-	 */
-
-	/* If we don't yet have a DHCPOFFER, do nothing */
-	ip_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP );
-	if ( ! ip_offer )
-		return;
-
-	/* If we can't yet transition to DHCPREQUEST, do nothing */
-	elapsed = ( currticks() - dhcp->start );
-	if ( ! ( ip_offer->no_pxedhcp ||
-		 dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) ||
-		 ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) )
-		return;
-
-	/* Transition to DHCPREQUEST */
-	dhcp_set_state ( dhcp, &dhcp_state_request );
-}
-
-/**
- * Handle timer expiry during DHCP discovery
- *
- * @v dhcp		DHCP session
- */
-static void dhcp_discovery_expired ( struct dhcp_session *dhcp ) {
-	unsigned long elapsed = ( currticks() - dhcp->start );
-
-	/* Give up waiting for ProxyDHCP before we reach the failure point */
-	if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) &&
-	     ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) {
-		dhcp_set_state ( dhcp, &dhcp_state_request );
-		return;
-	}
-
-	/* Otherwise, retransmit current packet */
-	dhcp_tx ( dhcp );
-}
-
-/** DHCP discovery state operations */
-static struct dhcp_session_state dhcp_state_discover = {
-	.name			= "discovery",
-	.tx			= dhcp_discovery_tx,
-	.rx			= dhcp_discovery_rx,
-	.expired		= dhcp_discovery_expired,
-	.tx_msgtype		= DHCPDISCOVER,
-	.apply_min_timeout	= 1,
-};
-
-/**
- * Construct transmitted packet for DHCP request
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		Destination address
- */
-static int dhcp_request_tx ( struct dhcp_session *dhcp,
-			     struct dhcp_packet *dhcppkt,
-			     struct sockaddr_in *peer ) {
-	int rc;
-	struct dhcp_offer *offer;
-
-	offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP );
-
-	DBGC ( dhcp, "DHCP %p DHCPREQUEST to %s:%d",
-	       dhcp, inet_ntoa ( offer->server ), BOOTPS_PORT );
-	DBGC ( dhcp, " for %s\n", inet_ntoa ( offer->ip ) );
-
-	/* Set server ID */
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
-				    &offer->server,
-				    sizeof ( offer->server ) ) ) != 0 )
-		return rc;
-
-	/* Set requested IP address */
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS,
-				    &offer->ip, sizeof ( offer->ip ) ) ) != 0 )
-		return rc;
-
-	/* Set server address */
-	peer->sin_addr.s_addr = INADDR_BROADCAST;
-	peer->sin_port = htons ( BOOTPS_PORT );
-
-	return 0;
-}
-
-/**
- * Handle received packet during DHCP request
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		DHCP server address
- * @v msgtype		DHCP message type
- * @v server_id		DHCP server ID
- */
-static void dhcp_request_rx ( struct dhcp_session *dhcp,
-			      struct dhcp_packet *dhcppkt,
-			      struct sockaddr_in *peer, uint8_t msgtype,
-			      struct in_addr server_id ) {
-	struct in_addr ip;
-	struct settings *parent;
-	int rc;
-	struct dhcp_offer *pxe_offer;
-
-	if ( msgtype == DHCPOFFER ) {
-		dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
-		if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) !=
-		     dhcp->current_offer ) {
-			/* Restart due to higher-priority offer received */
-			DBGC ( dhcp, "DHCP %p re-requesting\n", dhcp );
-			dhcp_set_state ( dhcp, &dhcp_state_request );
-		}
-		return;
-	}
-
-	DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
-	       dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
-	       ntohs ( peer->sin_port ) );
-	if ( server_id.s_addr != peer->sin_addr.s_addr )
-		DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
-
-	/* Identify leased IP address */
-	ip = dhcppkt->dhcphdr->yiaddr;
-	if ( ip.s_addr )
-		DBGC ( dhcp, " for %s", inet_ntoa ( ip ) );
-	DBGC ( dhcp, "\n" );
-
-	/* Filter out unacceptable responses */
-	if ( peer->sin_port != htons ( BOOTPS_PORT ) )
-		return;
-	if ( msgtype /* BOOTP */ && ( msgtype != DHCPACK ) )
-		return;
-	if ( server_id.s_addr != dhcp->current_offer->server.s_addr )
-		return;
-
-	/* Record assigned address */
-	dhcp->local.sin_addr = ip;
-
-	/* Register settings */
-	parent = netdev_settings ( dhcp->netdev );
-	if ( ( rc = register_settings ( &dhcppkt->settings, parent ) ) != 0 ){
-		DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
-		       dhcp, strerror ( rc ) );
-		dhcp_finished ( dhcp, rc );
-		return;
-	}
-
-	/* Locate best source of PXE settings */
-	pxe_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE );
-
-	if ( ( ! pxe_offer ) || /* No PXE available */
-	     /* IP offer instructs us to ignore PXE */
-	     dhcp->current_offer->no_pxedhcp ||
-	     /* PXE settings already registered with IP offer */
-	     ( ( dhcp->current_offer == pxe_offer ) && ( pxe_offer->pxe ) ) ) {
-
-		/* Terminate DHCP */
-		dhcp_finished ( dhcp, 0 );
-
-	} else if ( pxe_offer->pxe ) {
-		/* Register PXE settings and terminate DHCP */
-		pxe_offer->pxe->settings.name = PROXYDHCP_SETTINGS_NAME;
-		if ( ( rc = register_settings ( &pxe_offer->pxe->settings,
-						NULL ) ) != 0 ) {
-			DBGC ( dhcp, "DHCP %p could not register settings: "
-			       "%s\n", dhcp, strerror ( rc ) );
-		}
-		dhcp_finished ( dhcp, rc );
-	} else {
-		/* Start ProxyDHCP */
-		dhcp_set_state ( dhcp, &dhcp_state_proxy );
-	}
-}
-
-/**
- * Handle timer expiry during DHCP discovery
- *
- * @v dhcp		DHCP session
- */
-static void dhcp_request_expired ( struct dhcp_session *dhcp ) {
-
-	/* Retransmit current packet */
-	dhcp_tx ( dhcp );
-}
-
-/** DHCP request state operations */
-static struct dhcp_session_state dhcp_state_request = {
-	.name			= "request",
-	.tx			= dhcp_request_tx,
-	.rx			= dhcp_request_rx,
-	.expired		= dhcp_request_expired,
-	.tx_msgtype		= DHCPREQUEST,
-	.apply_min_timeout	= 0,
-};
-
-/**
- * Construct transmitted packet for ProxyDHCP request
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		Destination address
- */
-static int dhcp_proxy_tx ( struct dhcp_session *dhcp,
-			   struct dhcp_packet *dhcppkt,
-			   struct sockaddr_in *peer ) {
-	int rc;
-	struct dhcp_offer *offer;
-
-	offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE );
-
-	DBGC ( dhcp, "DHCP %p ProxyDHCP REQUEST to %s:%d\n", dhcp,
-	       inet_ntoa ( offer->server ), PXE_PORT );
-
-	/* Set server ID */
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
-				    &offer->server,
-				    sizeof ( offer->server ) ) )  != 0 )
-		return rc;
-
-	/* Set server address */
-	peer->sin_addr = offer->server;
-	peer->sin_port = htons ( PXE_PORT );
-
-	return 0;
-}
-
-/**
- * Handle received packet during ProxyDHCP request
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		DHCP server address
- * @v msgtype		DHCP message type
- * @v server_id		DHCP server ID
- */
-static void dhcp_proxy_rx ( struct dhcp_session *dhcp,
-			    struct dhcp_packet *dhcppkt,
-			    struct sockaddr_in *peer, uint8_t msgtype,
-			    struct in_addr server_id ) {
-	int rc;
-
-	/* Enqueue last-minute DHCPOFFERs for use in case of failure */
-	if ( peer->sin_port == htons ( BOOTPS_PORT ) &&
-	     msgtype == DHCPOFFER ) {
-		dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
-		return;
-	}
-
-	DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
-	       dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
-	       ntohs ( peer->sin_port ) );
-	if ( server_id.s_addr != peer->sin_addr.s_addr )
-		DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
-	DBGC ( dhcp, "\n" );
-
-	/* Filter out unacceptable responses */
-	if ( peer->sin_port != htons ( PXE_PORT ) )
-		return;
-	if ( msgtype != DHCPACK && msgtype != DHCPOFFER )
-		return;
-	if ( server_id.s_addr /* Linux PXE server omits server ID */ &&
-	     ( server_id.s_addr != dhcp->current_offer->server.s_addr ) )
-		return;
-
-	/* Register settings */
-	dhcppkt->settings.name = PROXYDHCP_SETTINGS_NAME;
-	if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) {
-		DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
-		       dhcp, strerror ( rc ) );
-		dhcp_finished ( dhcp, rc );
-		return;
-	}
-
-	/* Terminate DHCP */
-	dhcp_finished ( dhcp, 0 );
-}
-
-/**
- * Handle timer expiry during ProxyDHCP request
- *
- * @v dhcp		DHCP session
- */
-static void dhcp_proxy_expired ( struct dhcp_session *dhcp ) {
-	unsigned long elapsed = ( currticks() - dhcp->start );
-
-	/* Give up waiting for ProxyDHCP before we reach the failure point */
-	if ( elapsed > PROXYDHCP_MAX_TIMEOUT ) {
-
-		/* Mark failed offer as unsuitable for ProxyDHCP */
-		dhcp->current_offer->valid &= ~DHCP_OFFER_PXE;
-
-		/* Prefer not to use only half of a PXE+IP offer if we
-		 * have other offers available
-		 */
-		dhcp->current_offer->priority = -1;
-
-		/* If we have any other PXE offers we can try, go back
-		 * to DHCPREQUEST (since they might not be proxied
-		 * offers, or might be coupled to a new IP address).
-		 * We should probably DHCPRELEASE our old IP, but the
-		 * standard does not require it.
-		 */
-		if ( dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) ) {
-			dhcp->local.sin_addr.s_addr = 0;
-			dhcp_set_state ( dhcp, &dhcp_state_request );
-			return;
-		}
-
-		/* No possibilities left; finish without PXE options */
-		dhcp_finished ( dhcp, 0 );
-		return;
-	}
-
-	/* Retransmit current packet */
-	dhcp_tx ( dhcp );
-}
-
-/** ProxyDHCP request state operations */
-static struct dhcp_session_state dhcp_state_proxy = {
-	.name			= "ProxyDHCP",
-	.tx			= dhcp_proxy_tx,
-	.rx			= dhcp_proxy_rx,
-	.expired		= dhcp_proxy_expired,
-	.tx_msgtype		= DHCPREQUEST,
-	.apply_min_timeout	= 0,
-};
-
-/**
- * Construct transmitted packet for PXE Boot Server Discovery
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		Destination address
- */
-static int dhcp_pxebs_tx ( struct dhcp_session *dhcp,
-			   struct dhcp_packet *dhcppkt,
-			   struct sockaddr_in *peer ) {
-	struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 };
-	int rc;
-
-	/* Set server address */
-	peer->sin_addr = *(dhcp->pxe_attempt);
-	peer->sin_port = ( ( peer->sin_addr.s_addr == INADDR_BROADCAST ) ?
-			   htons ( BOOTPS_PORT ) : htons ( PXE_PORT ) );
-
-	DBGC ( dhcp, "DHCP %p PXEBS REQUEST to %s:%d for type %d\n",
-	       dhcp, inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ),
-	       le16_to_cpu ( dhcp->pxe_type ) );
-
-	/* Set boot menu item */
-	menu_item.type = dhcp->pxe_type;
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM,
-				    &menu_item, sizeof ( menu_item ) ) ) != 0 )
-		return rc;
-
-	return 0;
-}
-
-/**
- * Check to see if PXE Boot Server address is acceptable
- *
- * @v dhcp		DHCP session
- * @v bs		Boot Server address
- * @ret accept		Boot Server is acceptable
- */
-static int dhcp_pxebs_accept ( struct dhcp_session *dhcp,
-			       struct in_addr bs ) {
-	struct in_addr *accept;
-
-	/* Accept if we have no acceptance filter */
-	if ( ! dhcp->pxe_accept )
-		return 1;
-
-	/* Scan through acceptance list */
-	for ( accept = dhcp->pxe_accept ; accept->s_addr ; accept++ ) {
-		if ( accept->s_addr == bs.s_addr )
-			return 1;
-	}
-
-	DBGC ( dhcp, "DHCP %p rejecting server %s\n",
-	       dhcp, inet_ntoa ( bs ) );
-	return 0;
-}
-
-/**
- * Handle received packet during PXE Boot Server Discovery
- *
- * @v dhcp		DHCP session
- * @v dhcppkt		DHCP packet
- * @v peer		DHCP server address
- * @v msgtype		DHCP message type
- * @v server_id		DHCP server ID
- */
-static void dhcp_pxebs_rx ( struct dhcp_session *dhcp,
-			    struct dhcp_packet *dhcppkt,
-			    struct sockaddr_in *peer, uint8_t msgtype,
-			    struct in_addr server_id ) {
-	struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 };
-	int rc;
-
-	DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
-	       dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
-	       ntohs ( peer->sin_port ) );
-	if ( server_id.s_addr != peer->sin_addr.s_addr )
-		DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
-
-	/* Identify boot menu item */
-	dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM,
-			&menu_item, sizeof ( menu_item ) );
-	if ( menu_item.type )
-		DBGC ( dhcp, " for type %d", ntohs ( menu_item.type ) );
-	DBGC ( dhcp, "\n" );
-
-	/* Filter out unacceptable responses */
-	if ( ( peer->sin_port != htons ( BOOTPS_PORT ) ) &&
-	     ( peer->sin_port != htons ( PXE_PORT ) ) )
-		return;
-	if ( msgtype != DHCPACK )
-		return;
-	if ( menu_item.type != dhcp->pxe_type )
-		return;
-	if ( ! dhcp_pxebs_accept ( dhcp, ( server_id.s_addr ?
-					   server_id : peer->sin_addr ) ) )
-		return;
-
-	/* Register settings */
-	dhcppkt->settings.name = PXEBS_SETTINGS_NAME;
-	if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) {
-		DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
-		       dhcp, strerror ( rc ) );
-		dhcp_finished ( dhcp, rc );
-		return;
-	}
-
-	/* Terminate DHCP */
-	dhcp_finished ( dhcp, 0 );
-}
-
-/**
- * Handle timer expiry during PXE Boot Server Discovery
- *
- * @v dhcp		DHCP session
- */
-static void dhcp_pxebs_expired ( struct dhcp_session *dhcp ) {
-	unsigned long elapsed = ( currticks() - dhcp->start );
-
-	/* Give up waiting before we reach the failure point, and fail
-	 * over to the next server in the attempt list
-	 */
-	if ( elapsed > PXEBS_MAX_TIMEOUT ) {
-		dhcp->pxe_attempt++;
-		if ( dhcp->pxe_attempt->s_addr ) {
-			dhcp_set_state ( dhcp, &dhcp_state_pxebs );
-			return;
-		} else {
-			dhcp_finished ( dhcp, -ETIMEDOUT );
-			return;
-		}
-	}
-
-	/* Retransmit current packet */
-	dhcp_tx ( dhcp );
-}
-
-/** PXE Boot Server Discovery state operations */
-static struct dhcp_session_state dhcp_state_pxebs = {
-	.name			= "PXEBS",
-	.tx			= dhcp_pxebs_tx,
-	.rx			= dhcp_pxebs_rx,
-	.expired		= dhcp_pxebs_expired,
-	.tx_msgtype		= DHCPREQUEST,
-	.apply_min_timeout	= 1,
-};
-
-/****************************************************************************
- *
- * Packet construction
- *
- */
-
-/**
- * Construct DHCP client hardware address field and broadcast flag
- *
- * @v netdev		Network device
- * @v hlen		DHCP hardware address length to fill in
- * @v flags		DHCP flags to fill in
- * @ret chaddr		DHCP client hardware address
- */
-void * dhcp_chaddr ( struct net_device *netdev, uint8_t *hlen,
-		     uint16_t *flags ) {
-	struct ll_protocol *ll_protocol = netdev->ll_protocol;
-	typeof ( ( ( struct dhcphdr * ) NULL )->chaddr ) chaddr;
-
-	/* If the link-layer address cannot fit into the chaddr field
-	 * (as is the case for IPoIB) then try using the hardware
-	 * address instead.  If we do this, set the broadcast flag,
-	 * since chaddr then does not represent a valid link-layer
-	 * address for the return path.
-	 *
-	 * If even the hardware address is too large, use an empty
-	 * chaddr field and set the broadcast flag.
-	 *
-	 * This goes against RFC4390, but RFC4390 mandates that we use
-	 * a DHCP client identifier that conforms with RFC4361, which
-	 * we cannot do without either persistent (NIC-independent)
-	 * storage, or by eliminating the hardware address completely
-	 * from the DHCP packet, which seems unfriendly to users.
-	 */
-	if ( ( *hlen = ll_protocol->ll_addr_len ) <= sizeof ( chaddr ) ) {
-		return netdev->ll_addr;
-	}
-	*flags = htons ( BOOTP_FL_BROADCAST );
-	if ( ( *hlen = ll_protocol->hw_addr_len ) <= sizeof ( chaddr ) ) {
-		return netdev->hw_addr;
-	} else {
-		*hlen = 0;
-		return NULL;
-	}
-}
-
-/**
- * Create a DHCP packet
- *
- * @v dhcppkt		DHCP packet structure to fill in
- * @v netdev		Network device
- * @v msgtype		DHCP message type
- * @v options		Initial options to include (or NULL)
- * @v options_len	Length of initial options
- * @v data		Buffer for DHCP packet
- * @v max_len		Size of DHCP packet buffer
- * @ret rc		Return status code
- *
- * Creates a DHCP packet in the specified buffer, and initialise a
- * DHCP packet structure.
- */
-int dhcp_create_packet ( struct dhcp_packet *dhcppkt,
-			 struct net_device *netdev, uint8_t msgtype,
-			 const void *options, size_t options_len,
-			 void *data, size_t max_len ) {
-	struct dhcphdr *dhcphdr = data;
-	void *chaddr;
-	int rc;
-
-	/* Sanity check */
-	if ( max_len < ( sizeof ( *dhcphdr ) + options_len ) )
-		return -ENOSPC;
-
-	/* Initialise DHCP packet content */
-	memset ( dhcphdr, 0, max_len );
-	dhcphdr->xid = dhcp_xid ( netdev );
-	dhcphdr->magic = htonl ( DHCP_MAGIC_COOKIE );
-	dhcphdr->htype = ntohs ( netdev->ll_protocol->ll_proto );
-	dhcphdr->op = dhcp_op[msgtype];
-	chaddr = dhcp_chaddr ( netdev, &dhcphdr->hlen, &dhcphdr->flags );
-	memcpy ( dhcphdr->chaddr, chaddr, dhcphdr->hlen );
-	memcpy ( dhcphdr->options, options, options_len );
-
-	/* Initialise DHCP packet structure */
-	memset ( dhcppkt, 0, sizeof ( *dhcppkt ) );
-	dhcppkt_init ( dhcppkt, data, max_len );
-	
-	/* Set DHCP_MESSAGE_TYPE option */
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_MESSAGE_TYPE,
-				    &msgtype, sizeof ( msgtype ) ) ) != 0 )
-		return rc;
-
-	return 0;
-}
-
-/**
- * Create DHCP request packet
- *
- * @v dhcppkt		DHCP packet structure to fill in
- * @v netdev		Network device
- * @v msgtype		DHCP message type
- * @v ciaddr		Client IP address
- * @v data		Buffer for DHCP packet
- * @v max_len		Size of DHCP packet buffer
- * @ret rc		Return status code
- *
- * Creates a DHCP request packet in the specified buffer, and
- * initialise a DHCP packet structure.
- */
-int dhcp_create_request ( struct dhcp_packet *dhcppkt,
-			  struct net_device *netdev, unsigned int msgtype,
-			  struct in_addr ciaddr, void *data, size_t max_len ) {
-	struct dhcp_netdev_desc dhcp_desc;
-	struct dhcp_client_id client_id;
-	struct dhcp_client_uuid client_uuid;
-	uint8_t *dhcp_features;
-	size_t dhcp_features_len;
-	size_t ll_addr_len;
-	ssize_t len;
-	int rc;
-
-	/* Create DHCP packet */
-	if ( ( rc = dhcp_create_packet ( dhcppkt, netdev, msgtype,
-					 dhcp_request_options_data,
-					 sizeof ( dhcp_request_options_data ),
-					 data, max_len ) ) != 0 ) {
-		DBG ( "DHCP could not create DHCP packet: %s\n",
-		      strerror ( rc ) );
-		return rc;
-	}
-
-	/* Set client IP address */
-	dhcppkt->dhcphdr->ciaddr = ciaddr;
-
-	/* Add options to identify the feature list */
-	dhcp_features = table_start ( DHCP_FEATURES );
-	dhcp_features_len = table_num_entries ( DHCP_FEATURES );
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_ENCAP, dhcp_features,
-				    dhcp_features_len ) ) != 0 ) {
-		DBG ( "DHCP could not set features list option: %s\n",
-		      strerror ( rc ) );
-		return rc;
-	}
-
-	/* Add options to identify the network device */
-	fetch_setting ( &netdev->settings.settings, &busid_setting, &dhcp_desc,
-		sizeof ( dhcp_desc ) );
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_BUS_ID, &dhcp_desc,
-				    sizeof ( dhcp_desc ) ) ) != 0 ) {
-		DBG ( "DHCP could not set bus ID option: %s\n",
-		      strerror ( rc ) );
-		return rc;
-	}
-
-	/* Add DHCP client identifier.  Required for Infiniband, and
-	 * doesn't hurt other link layers.
-	 */
-	client_id.ll_proto = ntohs ( netdev->ll_protocol->ll_proto );
-	ll_addr_len = netdev->ll_protocol->ll_addr_len;
-	assert ( ll_addr_len <= sizeof ( client_id.ll_addr ) );
-	memcpy ( client_id.ll_addr, netdev->ll_addr, ll_addr_len );
-	if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_ID, &client_id,
-				    ( ll_addr_len + 1 ) ) ) != 0 ) {
-		DBG ( "DHCP could not set client ID: %s\n",
-		      strerror ( rc ) );
-		return rc;
-	}
-
-	/* Add client UUID, if we have one.  Required for PXE. */
-	client_uuid.type = DHCP_CLIENT_UUID_TYPE;
-	if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting,
-					  &client_uuid.uuid ) ) >= 0 ) {
-		if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_UUID,
-					    &client_uuid,
-					    sizeof ( client_uuid ) ) ) != 0 ) {
-			DBG ( "DHCP could not set client UUID: %s\n",
-			      strerror ( rc ) );
-			return rc;
-		}
-	}
-
-	/* Add user class, if we have one. */
-	if ( ( len = fetch_setting_len ( NULL, &user_class_setting ) ) >= 0 ) {
-		char user_class[len];
-		fetch_setting ( NULL, &user_class_setting, user_class,
-				sizeof ( user_class ) );
-		if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_USER_CLASS_ID,
-					    &user_class,
-					    sizeof ( user_class ) ) ) != 0 ) {
-			DBG ( "DHCP could not set user class: %s\n",
-			      strerror ( rc ) );
-			return rc;
-		}
-	}
-
-	return 0;
-}
-
-/****************************************************************************
- *
- * Data transfer interface
- *
- */
-
-/**
- * Transmit DHCP request
- *
- * @v dhcp		DHCP session
- * @ret rc		Return status code
- */
-static int dhcp_tx ( struct dhcp_session *dhcp ) {
-	static struct sockaddr_in peer = {
-		.sin_family = AF_INET,
-	};
-	struct xfer_metadata meta = {
-		.netdev = dhcp->netdev,
-		.src = ( struct sockaddr * ) &dhcp->local,
-		.dest = ( struct sockaddr * ) &peer,
-	};
-	struct io_buffer *iobuf;
-	uint8_t msgtype = dhcp->state->tx_msgtype;
-	struct dhcp_packet dhcppkt;
-	int rc;
-
-	/* Start retry timer.  Do this first so that failures to
-	 * transmit will be retried.
-	 */
-	start_timer ( &dhcp->timer );
-
-	/* Allocate buffer for packet */
-	iobuf = xfer_alloc_iob ( &dhcp->xfer, DHCP_MIN_LEN );
-	if ( ! iobuf )
-		return -ENOMEM;
-
-	/* Create basic DHCP packet in temporary buffer */
-	if ( ( rc = dhcp_create_request ( &dhcppkt, dhcp->netdev, msgtype,
-					  dhcp->local.sin_addr, iobuf->data,
-					  iob_tailroom ( iobuf ) ) ) != 0 ) {
-		DBGC ( dhcp, "DHCP %p could not construct DHCP request: %s\n",
-		       dhcp, strerror ( rc ) );
-		goto done;
-	}
-
-	/* Fill in packet based on current state */
-	if ( ( rc = dhcp->state->tx ( dhcp, &dhcppkt, &peer ) ) != 0 ) {
-		DBGC ( dhcp, "DHCP %p could not fill DHCP request: %s\n",
-		       dhcp, strerror ( rc ) );
-		goto done;
-	}
-
-	/* Transmit the packet */
-	iob_put ( iobuf, dhcppkt.len );
-	if ( ( rc = xfer_deliver_iob_meta ( &dhcp->xfer, iob_disown ( iobuf ),
-					    &meta ) ) != 0 ) {
-		DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n",
-		       dhcp, strerror ( rc ) );
-		goto done;
-	}
-
- done:
-	free_iob ( iobuf );
-	return rc;
-}
-
-/**
- * Receive new data
- *
- * @v xfer 		Data transfer interface
- * @v iobuf		I/O buffer
- * @v meta		Transfer metadata
- * @ret rc		Return status code
- */
-static int dhcp_deliver_iob ( struct xfer_interface *xfer,
-			      struct io_buffer *iobuf,
-			      struct xfer_metadata *meta ) {
-	struct dhcp_session *dhcp =
-		container_of ( xfer, struct dhcp_session, xfer );
-	struct sockaddr_in *peer;
-	size_t data_len;
-	struct dhcp_packet *dhcppkt;
-	struct dhcphdr *dhcphdr;
-	uint8_t msgtype = 0;
-	struct in_addr server_id = { 0 };
-	int rc = 0;
-
-	/* Sanity checks */
-	if ( ! meta->src ) {
-		DBGC ( dhcp, "DHCP %p received packet without source port\n",
-		       dhcp );
-		rc = -EINVAL;
-		goto err_no_src;
-	}
-	peer = ( struct sockaddr_in * ) meta->src;
-
-	/* Create a DHCP packet containing the I/O buffer contents.
-	 * Whilst we could just use the original buffer in situ, that
-	 * would waste the unused space in the packet buffer, and also
-	 * waste a relatively scarce fully-aligned I/O buffer.
-	 */
-	data_len = iob_len ( iobuf );
-	dhcppkt = zalloc ( sizeof ( *dhcppkt ) + data_len );
-	if ( ! dhcppkt ) {
-		rc = -ENOMEM;
-		goto err_alloc_dhcppkt;
-	}
-	dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
-	memcpy ( dhcphdr, iobuf->data, data_len );
-	dhcppkt_init ( dhcppkt, dhcphdr, data_len );
-
-	/* Identify message type */
-	dhcppkt_fetch ( dhcppkt, DHCP_MESSAGE_TYPE, &msgtype,
-			sizeof ( msgtype ) );
-
-	/* Identify server ID */
-	dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER,
-			&server_id, sizeof ( server_id ) );
-
-	/* Check for matching transaction ID */
-	if ( dhcphdr->xid != dhcp_xid ( dhcp->netdev ) ) {
-		DBGC ( dhcp, "DHCP %p %s from %s:%d has bad transaction "
-		       "ID\n", dhcp, dhcp_msgtype_name ( msgtype ),
-		       inet_ntoa ( peer->sin_addr ),
-		       ntohs ( peer->sin_port ) );
-		rc = -EINVAL;
-		goto err_xid;
-	};
-
-	/* Handle packet based on current state */
-	dhcp->state->rx ( dhcp, dhcppkt, peer, msgtype, server_id );
-
- err_xid:
-	dhcppkt_put ( dhcppkt );
- err_alloc_dhcppkt:
- err_no_src:
-	free_iob ( iobuf );
-	return rc;
-}
-
-/** DHCP data transfer interface operations */
-static struct xfer_interface_operations dhcp_xfer_operations = {
-	.close		= ignore_xfer_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= dhcp_deliver_iob,
-	.deliver_raw	= xfer_deliver_as_iob,
-};
-
-/**
- * Handle DHCP retry timer expiry
- *
- * @v timer		DHCP retry timer
- * @v fail		Failure indicator
- */
-static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) {
-	struct dhcp_session *dhcp =
-		container_of ( timer, struct dhcp_session, timer );
-
-	/* If we have failed, terminate DHCP */
-	if ( fail ) {
-		dhcp_finished ( dhcp, -ETIMEDOUT );
-		return;
-	}
-
-	/* Handle timer expiry based on current state */
-	dhcp->state->expired ( dhcp );
-}
-
-/****************************************************************************
- *
- * Job control interface
- *
- */
-
-/**
- * Handle kill() event received via job control interface
- *
- * @v job		DHCP job control interface
- */
-static void dhcp_job_kill ( struct job_interface *job ) {
-	struct dhcp_session *dhcp =
-		container_of ( job, struct dhcp_session, job );
-
-	/* Terminate DHCP session */
-	dhcp_finished ( dhcp, -ECANCELED );
-}
-
-/** DHCP job control interface operations */
-static struct job_interface_operations dhcp_job_operations = {
-	.done		= ignore_job_done,
-	.kill		= dhcp_job_kill,
-	.progress	= ignore_job_progress,
-};
-
-/****************************************************************************
- *
- * Instantiators
- *
- */
-
-/**
- * DHCP peer address for socket opening
- *
- * This is a dummy address; the only useful portion is the socket
- * family (so that we get a UDP connection).  The DHCP client will set
- * the IP address and source port explicitly on each transmission.
- */
-static struct sockaddr dhcp_peer = {
-	.sa_family = AF_INET,
-};
-
-/**
- * Start DHCP state machine on a network device
- *
- * @v job		Job control interface
- * @v netdev		Network device
- * @ret rc		Return status code, or positive if cached
- *
- * Starts DHCP on the specified network device.  If successful, the
- * DHCPACK (and ProxyDHCPACK, if applicable) will be registered as
- * option sources.
- *
- * On a return of 0, a background job has been started to perform the
- * DHCP request. Any nonzero return means the job has not been
- * started; a positive return value indicates the success condition of
- * having fetched the appropriate data from cached information.
- */
-int start_dhcp ( struct job_interface *job, struct net_device *netdev ) {
-	struct dhcp_session *dhcp;
-	int rc;
-
-	/* Check for cached DHCP information */
-	get_cached_dhcpack();
-	if ( fetch_uintz_setting ( NULL, &use_cached_setting ) ) {
-		DBG ( "DHCP using cached network settings\n" );
-		return 1;
-	}
-
-	/* Allocate and initialise structure */
-	dhcp = zalloc ( sizeof ( *dhcp ) );
-	if ( ! dhcp )
-		return -ENOMEM;
-	dhcp->refcnt.free = dhcp_free;
-	job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt );
-	xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
-	dhcp->netdev = netdev_get ( netdev );
-	dhcp->local.sin_family = AF_INET;
-	dhcp->local.sin_port = htons ( BOOTPC_PORT );
-	dhcp->timer.expired = dhcp_timer_expired;
-
-	/* Instantiate child objects and attach to our interfaces */
-	if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer,
-				  ( struct sockaddr * ) &dhcp->local ) ) != 0 )
-		goto err;
-
-	/* Enter DHCPDISCOVER state */
-	dhcp_set_state ( dhcp, &dhcp_state_discover );
-
-	/* Attach parent interface, mortalise self, and return */
-	job_plug_plug ( &dhcp->job, job );
-	ref_put ( &dhcp->refcnt );
-	return 0;
-
- err:
-	dhcp_finished ( dhcp, rc );
-	ref_put ( &dhcp->refcnt );
-	return rc;
-}
-
-/**
- * Retrieve list of PXE boot servers for a given server type
- *
- * @v dhcp		DHCP session
- * @v raw		DHCP PXE boot server list
- * @v raw_len		Length of DHCP PXE boot server list
- * @v ip		IP address list to fill in
- *
- * The caller must ensure that the IP address list has sufficient
- * space.
- */
-static void pxebs_list ( struct dhcp_session *dhcp, void *raw,
-			 size_t raw_len, struct in_addr *ip ) {
-	struct dhcp_pxe_boot_server *server = raw;
-	size_t server_len;
-	unsigned int i;
-
-	while ( raw_len ) {
-		if ( raw_len < sizeof ( *server ) ) {
-			DBGC ( dhcp, "DHCP %p malformed PXE server list\n",
-			       dhcp );
-			break;
-		}
-		server_len = offsetof ( typeof ( *server ),
-					ip[ server->num_ip ] );
-		if ( raw_len < server_len ) {
-			DBGC ( dhcp, "DHCP %p malformed PXE server list\n",
-			       dhcp );
-			break;
-		}
-		if ( server->type == dhcp->pxe_type ) {
-			for ( i = 0 ; i < server->num_ip ; i++ )
-				*(ip++) = server->ip[i];
-		}
-		server = ( ( ( void * ) server ) + server_len );
-		raw_len -= server_len;
-	}
-}
-
-/**
- * Start PXE Boot Server Discovery on a network device
- *
- * @v job		Job control interface
- * @v netdev		Network device
- * @v pxe_type		PXE server type
- * @ret rc		Return status code
- *
- * Starts PXE Boot Server Discovery on the specified network device.
- * If successful, the Boot Server ACK will be registered as an option
- * source.
- */
-int start_pxebs ( struct job_interface *job, struct net_device *netdev,
-		  unsigned int pxe_type ) {
-	struct setting pxe_discovery_control_setting =
-		{ .tag = DHCP_PXE_DISCOVERY_CONTROL };
-	struct setting pxe_boot_servers_setting =
-		{ .tag = DHCP_PXE_BOOT_SERVERS };
-	struct setting pxe_boot_server_mcast_setting =
-		{ .tag = DHCP_PXE_BOOT_SERVER_MCAST };
-	ssize_t pxebs_list_len;
-	struct dhcp_session *dhcp;
-	struct in_addr *ip;
-	unsigned int pxe_discovery_control;
-	int rc;
-
-	/* Get upper bound for PXE boot server IP address list */
-	pxebs_list_len = fetch_setting_len ( NULL, &pxe_boot_servers_setting );
-	if ( pxebs_list_len < 0 )
-		pxebs_list_len = 0;
-
-	/* Allocate and initialise structure */
-	dhcp = zalloc ( sizeof ( *dhcp ) + sizeof ( *ip ) /* mcast */ +
-			sizeof ( *ip ) /* bcast */ + pxebs_list_len +
-			sizeof ( *ip ) /* terminator */ );
-	if ( ! dhcp )
-		return -ENOMEM;
-	dhcp->refcnt.free = dhcp_free;
-	job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt );
-	xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
-	dhcp->netdev = netdev_get ( netdev );
-	dhcp->local.sin_family = AF_INET;
-	fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting,
-			     &dhcp->local.sin_addr );
-	dhcp->local.sin_port = htons ( BOOTPC_PORT );
-	dhcp->pxe_type = cpu_to_le16 ( pxe_type );
-	dhcp->timer.expired = dhcp_timer_expired;
-
-	/* Construct PXE boot server IP address lists */
-	pxe_discovery_control =
-		fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );
-	ip = ( ( ( void * ) dhcp ) + sizeof ( *dhcp ) );
-	dhcp->pxe_attempt = ip;
-	if ( ! ( pxe_discovery_control & PXEBS_NO_MULTICAST ) ) {
-		fetch_ipv4_setting ( NULL, &pxe_boot_server_mcast_setting, ip);
-		if ( ip->s_addr )
-			ip++;
-	}
-	if ( ! ( pxe_discovery_control & PXEBS_NO_BROADCAST ) )
-		(ip++)->s_addr = INADDR_BROADCAST;
-	if ( pxe_discovery_control & PXEBS_NO_UNKNOWN_SERVERS )
-		dhcp->pxe_accept = ip;
-	if ( pxebs_list_len ) {
-		uint8_t buf[pxebs_list_len];
-
-		fetch_setting ( NULL, &pxe_boot_servers_setting,
-				buf, sizeof ( buf ) );
-		pxebs_list ( dhcp, buf, sizeof ( buf ), ip );
-	}
-	if ( ! dhcp->pxe_attempt->s_addr ) {
-		DBGC ( dhcp, "DHCP %p has no PXE boot servers for type %04x\n",
-		       dhcp, pxe_type );
-		rc = -EINVAL;
-		goto err;
-	}
-
-	/* Dump out PXE server lists */
-	DBGC ( dhcp, "DHCP %p attempting", dhcp );
-	for ( ip = dhcp->pxe_attempt ; ip->s_addr ; ip++ )
-		DBGC ( dhcp, " %s", inet_ntoa ( *ip ) );
-	DBGC ( dhcp, "\n" );
-	if ( dhcp->pxe_accept ) {
-		DBGC ( dhcp, "DHCP %p accepting", dhcp );
-		for ( ip = dhcp->pxe_accept ; ip->s_addr ; ip++ )
-			DBGC ( dhcp, " %s", inet_ntoa ( *ip ) );
-		DBGC ( dhcp, "\n" );
-	}
-
-	/* Instantiate child objects and attach to our interfaces */
-	if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer,
-				  ( struct sockaddr * ) &dhcp->local ) ) != 0 )
-		goto err;
-
-	/* Enter PXEBS state */
-	dhcp_set_state ( dhcp, &dhcp_state_pxebs );
-
-	/* Attach parent interface, mortalise self, and return */
-	job_plug_plug ( &dhcp->job, job );
-	ref_put ( &dhcp->refcnt );
-	return 0;
-
- err:
-	dhcp_finished ( dhcp, rc );
-	ref_put ( &dhcp->refcnt );
-	return rc;
-}