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qemu / ipxe / ea33ea33c0d77b853c39d7b0e8c54f1a6f56b6bc / . / src / net / udp / dhcp.c
blob: a335a778a125b7254bef516e50015847a49c5831 [file] [log] [blame]
/*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <byteswap.h>
#include <ipxe/if_ether.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>
#include <ipxe/device.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/job.h>
#include <ipxe/retry.h>
#include <ipxe/tcpip.h>
#include <ipxe/ip.h>
#include <ipxe/uuid.h>
#include <ipxe/timer.h>
#include <ipxe/settings.h>
#include <ipxe/dhcp.h>
#include <ipxe/dhcpopts.h>
#include <ipxe/dhcppkt.h>
#include <ipxe/dhcp_arch.h>
#include <ipxe/features.h>
#include <config/dhcp.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 ( DHCP_ARCH_CLIENT_ARCHITECTURE ),
DHCP_CLIENT_NDI, DHCP_OPTION ( DHCP_ARCH_CLIENT_NDI ),
DHCP_VENDOR_CLASS_ID,
DHCP_STRING ( DHCP_VENDOR_PXECLIENT ( DHCP_ARCH_CLIENT_ARCHITECTURE,
DHCP_ARCH_CLIENT_NDI ) ),
DHCP_USER_CLASS_ID, DHCP_STRING ( 'i', '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_MTU, DHCP_VENDOR_ENCAP,
DHCP_VENDOR_CLASS_ID, DHCP_TFTP_SERVER_NAME,
DHCP_BOOTFILE_NAME, DHCP_DOMAIN_SEARCH,
128, 129, 130, 131, 132, 133, 134, 135, /* for PXE */
DHCP_EB_ENCAP, DHCP_ISCSI_INITIATOR_IQN ),
DHCP_END
};
/** Settings copied in to all DHCP requests */
static const struct setting * dhcp_request_settings[] = {
&user_class_setting,
&vendor_class_setting,
};
/** DHCP server address setting */
const struct setting dhcp_server_setting __setting ( SETTING_MISC,
dhcp-server ) = {
.name = "dhcp-server",
.description = "DHCP server",
.tag = DHCP_SERVER_IDENTIFIER,
.type = &setting_type_ipv4,
};
/**
* Most recent DHCP transaction ID
*
* This is exposed for use by the fakedhcp code when reconstructing
* DHCP packets for PXE NBPs.
*/
uint32_t dhcp_last_xid;
/**
* 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>";
}
}
/****************************************************************************
*
* 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
* @v pseudo_id DHCP server pseudo-ID
*/
void ( * rx ) ( struct dhcp_session *dhcp, struct dhcp_packet *dhcppkt,
struct sockaddr_in *peer, uint8_t msgtype,
struct in_addr server_id, struct in_addr pseudo_id );
/**
* Handle timer expiry
*
* @v dhcp DHCP session
*/
void ( * expired ) ( struct dhcp_session *dhcp );
/** Transmitted message type */
uint8_t tx_msgtype;
/** Timeout parameters */
uint8_t min_timeout_sec;
uint8_t max_timeout_sec;
};
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;
/** A DHCP session */
struct dhcp_session {
/** Reference counter */
struct refcnt refcnt;
/** Job control interface */
struct interface job;
/** Data transfer interface */
struct 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;
/** Transaction ID (in network-endian order) */
uint32_t xid;
/** Offered IP address */
struct in_addr offer;
/** DHCP server */
struct in_addr server;
/** DHCP offer priority */
int priority;
/** ProxyDHCP protocol extensions should be ignored */
int no_pxedhcp;
/** ProxyDHCP server */
struct in_addr proxy_server;
/** ProxyDHCP offer */
struct dhcp_packet *proxy_offer;
/** ProxyDHCP offer priority */
int proxy_priority;
/** 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;
/** Transmission counter */
unsigned int count;
/** Start time of the current state (in ticks) */
unsigned long start;
};
/**
* 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 );
netdev_put ( dhcp->netdev );
dhcppkt_put ( dhcp->proxy_offer );
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 ) {
/* Stop retry timer */
stop_timer ( &dhcp->timer );
/* Shut down interfaces */
intf_shutdown ( &dhcp->xfer, rc );
intf_shutdown ( &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 );
set_timer_limits ( &dhcp->timer,
( state->min_timeout_sec * TICKS_PER_SEC ),
( state->max_timeout_sec * TICKS_PER_SEC ) );
start_timer_nodelay ( &dhcp->timer );
}
/**
* Check if DHCP packet contains PXE options
*
* @v dhcppkt DHCP packet
* @ret has_pxeopts DHCP packet contains PXE options
*
* It is assumed that the packet is already known to contain option 60
* set to "PXEClient".
*/
static int dhcp_has_pxeopts ( struct dhcp_packet *dhcppkt ) {
/* Check for a next-server and boot filename */
if ( dhcppkt->dhcphdr->siaddr.s_addr &&
( dhcppkt_fetch ( dhcppkt, DHCP_BOOTFILE_NAME, NULL, 0 ) > 0 ) )
return 1;
/* Check for a PXE boot menu */
if ( dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU, NULL, 0 ) > 0 )
return 1;
return 0;
}
/****************************************************************************
*
* 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 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
* @v pseudo_id DHCP server pseudo-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,
struct in_addr pseudo_id ) {
struct in_addr ip;
char vci[9]; /* "PXEClient" */
int vci_len;
int has_pxeclient;
int8_t priority = 0;
uint8_t no_pxedhcp = 0;
unsigned long elapsed;
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 ) ||
( pseudo_id.s_addr != peer->sin_addr.s_addr ) ) {
DBGC ( dhcp, " (%s/", inet_ntoa ( server_id ) );
DBGC ( dhcp, "%s)", inet_ntoa ( pseudo_id ) );
}
/* Identify offered IP address */
ip = dhcppkt->dhcphdr->yiaddr;
if ( ip.s_addr )
DBGC ( dhcp, " for %s", inet_ntoa ( ip ) );
/* 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 ));
if ( has_pxeclient ) {
DBGC ( dhcp, "%s",
( dhcp_has_pxeopts ( dhcppkt ) ? " pxe" : " proxy" ) );
}
/* Identify priority */
dhcppkt_fetch ( dhcppkt, DHCP_EB_PRIORITY, &priority,
sizeof ( priority ) );
if ( priority )
DBGC ( dhcp, " pri %d", priority );
/* Identify ignore-PXE flag */
dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &no_pxedhcp,
sizeof ( no_pxedhcp ) );
if ( no_pxedhcp )
DBGC ( dhcp, " nopxe" );
DBGC ( dhcp, "\n" );
/* Select as DHCP offer, if applicable */
if ( ip.s_addr && ( peer->sin_port == htons ( BOOTPS_PORT ) ) &&
( ( msgtype == DHCPOFFER ) || ( ! msgtype /* BOOTP */ ) ) &&
( priority >= dhcp->priority ) ) {
dhcp->offer = ip;
dhcp->server = server_id;
dhcp->priority = priority;
dhcp->no_pxedhcp = no_pxedhcp;
}
/* Select as ProxyDHCP offer, if applicable */
if ( pseudo_id.s_addr && has_pxeclient &&
( priority >= dhcp->proxy_priority ) ) {
dhcppkt_put ( dhcp->proxy_offer );
dhcp->proxy_server = pseudo_id;
dhcp->proxy_offer = dhcppkt_get ( dhcppkt );
dhcp->proxy_priority = priority;
}
/* 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 */
if ( ! dhcp->offer.s_addr )
return;
/* If we can't yet transition to DHCPREQUEST, do nothing */
elapsed = ( currticks() - dhcp->start );
if ( ! ( dhcp->no_pxedhcp || dhcp->proxy_offer ||
( elapsed > DHCP_DISC_PROXY_TIMEOUT_SEC * TICKS_PER_SEC ) ) )
return;
/* Transition to DHCPREQUEST */
dhcp_set_state ( dhcp, &dhcp_state_request );
}
/**
* Defer DHCP discovery
*
* @v dhcp DHCP session
*/
static void dhcp_defer ( struct dhcp_session *dhcp ) {
/* Do nothing if we have reached the deferral limit */
if ( dhcp->count > DHCP_DISC_MAX_DEFERRALS )
return;
/* Return to discovery state */
DBGC ( dhcp, "DHCP %p deferring discovery\n", dhcp );
dhcp_set_state ( dhcp, &dhcp_state_discover );
/* Delay first DHCPDISCOVER */
start_timer_fixed ( &dhcp->timer,
( DHCP_DISC_START_TIMEOUT_SEC * TICKS_PER_SEC ) );
}
/**
* 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->offer.s_addr &&
( elapsed > DHCP_DISC_PROXY_TIMEOUT_SEC * TICKS_PER_SEC ) ) {
dhcp_set_state ( dhcp, &dhcp_state_request );
return;
}
/* Retransmit current packet */
dhcp_tx ( dhcp );
/* If link is blocked, defer DHCP discovery timeout */
if ( netdev_link_blocked ( dhcp->netdev ) )
dhcp_defer ( 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,
.min_timeout_sec = DHCP_DISC_START_TIMEOUT_SEC,
.max_timeout_sec = DHCP_DISC_END_TIMEOUT_SEC,
};
/**
* 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;
DBGC ( dhcp, "DHCP %p DHCPREQUEST to %s:%d",
dhcp, inet_ntoa ( dhcp->server ), BOOTPS_PORT );
DBGC ( dhcp, " for %s\n", inet_ntoa ( dhcp->offer ) );
/* Set server ID */
if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
&dhcp->server,
sizeof ( dhcp->server ) ) ) != 0 )
return rc;
/* Set requested IP address */
if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS,
&dhcp->offer,
sizeof ( dhcp->offer ) ) ) != 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
* @v pseudo_id DHCP server pseudo-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 pseudo_id ) {
struct in_addr ip;
struct settings *parent;
struct settings *settings;
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 ) ||
( pseudo_id.s_addr != peer->sin_addr.s_addr ) ) {
DBGC ( dhcp, " (%s/", inet_ntoa ( server_id ) );
DBGC ( dhcp, "%s)", inet_ntoa ( pseudo_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 invalid port */
if ( peer->sin_port != htons ( BOOTPS_PORT ) )
return;
/* Handle DHCPNAK */
if ( msgtype == DHCPNAK ) {
dhcp_defer ( dhcp );
return;
}
/* Filter out unacceptable responses */
if ( msgtype /* BOOTP */ && ( msgtype != DHCPACK ) )
return;
if ( server_id.s_addr != dhcp->server.s_addr )
return;
if ( ip.s_addr != dhcp->offer.s_addr )
return;
/* Record assigned address */
dhcp->local.sin_addr = ip;
/* Register settings */
parent = netdev_settings ( dhcp->netdev );
settings = &dhcppkt->settings;
if ( ( rc = register_settings ( settings, parent,
DHCP_SETTINGS_NAME ) ) != 0 ) {
DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
dhcp, strerror ( rc ) );
dhcp_finished ( dhcp, rc );
return;
}
/* Perform ProxyDHCP if applicable */
if ( dhcp->proxy_offer /* Have ProxyDHCP offer */ &&
( ! dhcp->no_pxedhcp ) /* ProxyDHCP not disabled */ ) {
if ( dhcp_has_pxeopts ( dhcp->proxy_offer ) ) {
/* PXE options already present; register settings
* without performing a ProxyDHCPREQUEST
*/
settings = &dhcp->proxy_offer->settings;
if ( ( rc = register_settings ( settings, NULL,
PROXYDHCP_SETTINGS_NAME ) ) != 0 ) {
DBGC ( dhcp, "DHCP %p could not register "
"proxy settings: %s\n",
dhcp, strerror ( rc ) );
dhcp_finished ( dhcp, rc );
return;
}
} else {
/* PXE options not present; use a ProxyDHCPREQUEST */
dhcp_set_state ( dhcp, &dhcp_state_proxy );
return;
}
}
/* Terminate DHCP */
dhcp_finished ( dhcp, 0 );
}
/**
* 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,
.min_timeout_sec = DHCP_REQ_START_TIMEOUT_SEC,
.max_timeout_sec = DHCP_REQ_END_TIMEOUT_SEC,
};
/**
* 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;
DBGC ( dhcp, "DHCP %p ProxyDHCP REQUEST to %s\n", dhcp,
inet_ntoa ( dhcp->proxy_server ) );
/* Set server ID */
if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
&dhcp->proxy_server,
sizeof ( dhcp->proxy_server ) ) ) != 0 )
return rc;
/* Set server address */
peer->sin_addr = dhcp->proxy_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
* @v pseudo_id DHCP server pseudo-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,
struct in_addr pseudo_id ) {
struct settings *settings = &dhcppkt->settings;
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 ) ||
( pseudo_id.s_addr != peer->sin_addr.s_addr ) ) {
DBGC ( dhcp, " (%s/", inet_ntoa ( server_id ) );
DBGC ( dhcp, "%s)", inet_ntoa ( pseudo_id ) );
}
if ( dhcp_has_pxeopts ( dhcppkt ) )
DBGC ( dhcp, " pxe" );
DBGC ( dhcp, "\n" );
/* Filter out unacceptable responses */
if ( peer->sin_port != ntohs ( PXE_PORT ) )
return;
if ( ( msgtype != DHCPOFFER ) && ( msgtype != DHCPACK ) )
return;
if ( ( pseudo_id.s_addr != dhcp->proxy_server.s_addr ) )
return;
if ( ! dhcp_has_pxeopts ( dhcppkt ) )
return;
/* Register settings */
if ( ( rc = register_settings ( settings, NULL,
PROXYDHCP_SETTINGS_NAME ) ) != 0 ) {
DBGC ( dhcp, "DHCP %p could not register proxy 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 > DHCP_REQ_PROXY_TIMEOUT_SEC * TICKS_PER_SEC ) {
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,
.min_timeout_sec = DHCP_PROXY_START_TIMEOUT_SEC,
.max_timeout_sec = DHCP_PROXY_END_TIMEOUT_SEC,
};
/**
* 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
* @v pseudo_id DHCP server pseudo-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 in_addr pseudo_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 ) ||
( pseudo_id.s_addr != peer->sin_addr.s_addr ) ) {
DBGC ( dhcp, " (%s/", inet_ntoa ( server_id ) );
DBGC ( dhcp, "%s)", inet_ntoa ( pseudo_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, pseudo_id ) )
return;
/* Register settings */
if ( ( rc = register_settings ( &dhcppkt->settings, NULL,
PXEBS_SETTINGS_NAME ) ) != 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_SEC * TICKS_PER_SEC ) {
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,
.min_timeout_sec = PXEBS_START_TIMEOUT_SEC,
.max_timeout_sec = PXEBS_END_TIMEOUT_SEC,
};
/****************************************************************************
*
* Packet construction
*
*/
/**
* Create a DHCP packet
*
* @v dhcppkt DHCP packet structure to fill in
* @v netdev Network device
* @v msgtype DHCP message type
* @v xid Transaction ID (in network-endian order)
* @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,
uint32_t xid, const void *options, size_t options_len,
void *data, size_t max_len ) {
struct dhcphdr *dhcphdr = data;
int rc;
/* Sanity check */
if ( max_len < ( sizeof ( *dhcphdr ) + options_len ) )
return -ENOSPC;
/* Initialise DHCP packet content */
memset ( dhcphdr, 0, max_len );
dhcphdr->xid = xid;
dhcphdr->magic = htonl ( DHCP_MAGIC_COOKIE );
dhcphdr->htype = ntohs ( netdev->ll_protocol->ll_proto );
dhcphdr->op = dhcp_op[msgtype];
dhcphdr->hlen = netdev->ll_protocol->ll_addr_len;
memcpy ( dhcphdr->chaddr, netdev->ll_addr,
netdev->ll_protocol->ll_addr_len );
memcpy ( dhcphdr->options, options, options_len );
/* If the local link-layer address functions only as a name
* (i.e. cannot be used as a destination address), then
* request broadcast responses.
*/
if ( netdev->ll_protocol->flags & LL_NAME_ONLY )
dhcphdr->flags |= htons ( BOOTP_FL_BROADCAST );
/* If the network device already has an IPv4 address then
* unicast responses from the DHCP server may be rejected, so
* request broadcast responses.
*/
if ( ipv4_has_any_addr ( netdev ) )
dhcphdr->flags |= htons ( BOOTP_FL_BROADCAST );
/* 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 xid Transaction ID (in network-endian order)
* @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,
uint32_t xid, 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;
const struct setting *setting;
uint8_t *dhcp_features;
size_t dhcp_features_len;
size_t ll_addr_len;
void *raw;
ssize_t len;
unsigned int i;
int rc;
/* Create DHCP packet */
if ( ( rc = dhcp_create_packet ( dhcppkt, netdev, msgtype, xid,
dhcp_request_options_data,
sizeof ( dhcp_request_options_data ),
data, max_len ) ) != 0 ) {
DBG ( "DHCP could not create DHCP packet: %s\n",
strerror ( rc ) );
goto err_create_packet;
}
/* 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 ) );
goto err_store_features;
}
/* Add options to identify the network device */
fetch_raw_setting ( netdev_settings ( netdev ), &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 ) );
goto err_store_busid;
}
/* 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 ) );
goto err_store_client_id;
}
/* Add client UUID, if we have one. Required for PXE. The
* PXE spec does not specify a byte ordering for UUIDs, but
* RFC4578 suggests that it follows the EFI spec, in which the
* first three fields are little-endian.
*/
client_uuid.type = DHCP_CLIENT_UUID_TYPE;
if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting,
&client_uuid.uuid ) ) >= 0 ) {
uuid_mangle ( &client_uuid.uuid );
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 ) );
goto err_store_client_uuid;
}
}
/* Add request settings, if applicable */
for ( i = 0 ; i < ( sizeof ( dhcp_request_settings ) /
sizeof ( dhcp_request_settings[0] ) ) ; i++ ) {
setting = dhcp_request_settings[i];
if ( ( len = fetch_raw_setting_copy ( NULL, setting,
&raw ) ) >= 0 ) {
rc = dhcppkt_store ( dhcppkt, setting->tag, raw, len );
free ( raw );
if ( rc != 0 ) {
DBG ( "DHCP could not set %s: %s\n",
setting->name, strerror ( rc ) );
goto err_store_raw;
}
}
}
err_store_raw:
err_store_client_uuid:
err_store_client_id:
err_store_busid:
err_store_features:
err_create_packet:
return rc;
}
/****************************************************************************
*
* 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->xid, 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;
}
/* (Ab)use the "secs" field to convey metadata about the DHCP
* session state into packet traces. Useful for extracting
* debug information from non-debug builds.
*/
dhcppkt.dhcphdr->secs = htons ( ( dhcp->count << 2 ) |
( dhcp->offer.s_addr ? 0x02 : 0 ) |
( dhcp->proxy_offer ? 0x01 : 0 ) );
/* 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 ( &dhcppkt ) );
if ( ( rc = xfer_deliver ( &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 dhcp DHCP session
* @v iobuf I/O buffer
* @v meta Transfer metadata
* @ret rc Return status code
*/
static int dhcp_deliver ( struct dhcp_session *dhcp,
struct io_buffer *iobuf,
struct xfer_metadata *meta ) {
struct net_device *netdev = dhcp->netdev;
struct ll_protocol *ll_protocol = netdev->ll_protocol;
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 };
struct in_addr pseudo_id;
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 ) );
/* Identify server pseudo-ID */
pseudo_id = server_id;
if ( ! pseudo_id.s_addr )
pseudo_id = dhcppkt->dhcphdr->siaddr;
if ( ! pseudo_id.s_addr )
pseudo_id = peer->sin_addr;
/* Check for matching transaction ID */
if ( dhcphdr->xid != dhcp->xid ) {
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;
};
/* Check for matching client hardware address */
if ( memcmp ( dhcphdr->chaddr, netdev->ll_addr,
ll_protocol->ll_addr_len ) != 0 ) {
DBGC ( dhcp, "DHCP %p %s from %s:%d has bad chaddr %s\n",
dhcp, dhcp_msgtype_name ( msgtype ),
inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ),
ll_protocol->ntoa ( dhcphdr->chaddr ) );
rc = -EINVAL;
goto err_chaddr;
}
/* Handle packet based on current state */
dhcp->state->rx ( dhcp, dhcppkt, peer, msgtype, server_id, pseudo_id );
err_chaddr:
err_xid:
dhcppkt_put ( dhcppkt );
err_alloc_dhcppkt:
err_no_src:
free_iob ( iobuf );
return rc;
}
/** DHCP data transfer interface operations */
static struct interface_operation dhcp_xfer_operations[] = {
INTF_OP ( xfer_deliver, struct dhcp_session *, dhcp_deliver ),
};
/** DHCP data transfer interface descriptor */
static struct interface_descriptor dhcp_xfer_desc =
INTF_DESC ( struct dhcp_session, xfer, dhcp_xfer_operations );
/**
* 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;
}
/* Increment transmission counter */
dhcp->count++;
/* Handle timer expiry based on current state */
dhcp->state->expired ( dhcp );
}
/****************************************************************************
*
* Job control interface
*
*/
/** DHCP job control interface operations */
static struct interface_operation dhcp_job_op[] = {
INTF_OP ( intf_close, struct dhcp_session *, dhcp_finished ),
};
/** DHCP job control interface descriptor */
static struct interface_descriptor dhcp_job_desc =
INTF_DESC ( struct dhcp_session, job, dhcp_job_op );
/****************************************************************************
*
* 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
*
* Starts DHCP on the specified network device. If successful, the
* DHCPACK (and ProxyDHCPACK, if applicable) will be registered as
* option sources.
*/
int start_dhcp ( struct interface *job, struct net_device *netdev ) {
struct dhcp_session *dhcp;
int rc;
/* Allocate and initialise structure */
dhcp = zalloc ( sizeof ( *dhcp ) );
if ( ! dhcp )
return -ENOMEM;
ref_init ( &dhcp->refcnt, dhcp_free );
intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
timer_init ( &dhcp->timer, dhcp_timer_expired, &dhcp->refcnt );
dhcp->netdev = netdev_get ( netdev );
dhcp->local.sin_family = AF_INET;
dhcp->local.sin_port = htons ( BOOTPC_PORT );
dhcp->xid = random();
/* Store DHCP transaction ID for fakedhcp code */
dhcp_last_xid = dhcp->xid;
/* 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 */
intf_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 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_raw_setting ( NULL, &pxe_boot_servers_setting,
NULL, 0 );
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;
ref_init ( &dhcp->refcnt, dhcp_free );
intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
timer_init ( &dhcp->timer, dhcp_timer_expired, &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 );
/* 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_raw_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 */
intf_plug_plug ( &dhcp->job, job );
ref_put ( &dhcp->refcnt );
return 0;
err:
dhcp_finished ( dhcp, rc );
ref_put ( &dhcp->refcnt );
return rc;
}
/** DHCP network device configurator */
struct net_device_configurator dhcp_configurator __net_device_configurator = {
.name = "dhcp",
.start = start_dhcp,
};