/*
* 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.
*/
#include <string.h>
#include <stdlib.h>
#include <stdio.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/dhcp.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
*
*/
/**
* 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_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_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
};
/** Options common to all DHCP requests */
static struct dhcp_options dhcp_request_options = {
.data = dhcp_request_options_data,
.max_len = sizeof ( dhcp_request_options_data ),
.len = sizeof ( dhcp_request_options_data ),
};
/** DHCP feature codes */
static uint8_t dhcp_features[0] __table_start ( uint8_t, dhcp_features );
static uint8_t dhcp_features_end[0] __table_end ( uint8_t, dhcp_features );
/** Version number feature */
FEATURE_VERSION ( VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH );
/** DHCP network device descriptor */
struct dhcp_netdev_desc {
/** Bus type ID */
uint8_t type;
/** Vendor ID */
uint16_t vendor;
/** Device ID */
uint16_t device;
} __attribute__ (( packed ));
/** DHCP client identifier */
struct dhcp_client_id {
/** Link-layer protocol */
uint8_t ll_proto;
/** Link-layer address */
uint8_t ll_addr[MAX_LL_ADDR_LEN];
} __attribute__ (( packed ));
/** DHCP client UUID */
struct dhcp_client_uuid {
/** Identifier type */
uint8_t type;
/** UUID */
union uuid uuid;
} __attribute__ (( packed ));
#define DHCP_CLIENT_UUID_TYPE 0
/** DHCP PXE boot menu item */
struct dhcp_pxe_boot_menu_item {
/** "Type"
*
* This field actually identifies the specific boot server (or
* cluster of boot servers offering identical boot files).
*/
uint16_t type;
/** "Layer"
*
* Just don't ask.
*/
uint16_t layer;
} __attribute__ (( packed ));
/**
* 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 settings
*
*/
/** A DHCP settings block */
struct dhcp_settings {
/** Reference counter */
struct refcnt refcnt;
/** DHCP packet */
struct dhcp_packet dhcppkt;
/** Setting interface */
struct settings settings;
};
/**
* Increment reference count on DHCP settings block
*
* @v dhcpset DHCP settings block
* @ret dhcpset DHCP settings block
*/
static inline __attribute__ (( always_inline )) struct dhcp_settings *
dhcpset_get ( struct dhcp_settings *dhcpset ) {
ref_get ( &dhcpset->refcnt );
return dhcpset;
}
/**
* Decrement reference count on DHCP settings block
*
* @v dhcpset DHCP settings block
*/
static inline __attribute__ (( always_inline )) void
dhcpset_put ( struct dhcp_settings *dhcpset ) {
ref_put ( &dhcpset->refcnt );
}
/**
* Store value of DHCP setting
*
* @v settings Settings block
* @v setting Setting to store
* @v data Setting data, or NULL to clear setting
* @v len Length of setting data
* @ret rc Return status code
*/
static int dhcpset_store ( struct settings *settings, struct setting *setting,
const void *data, size_t len ) {
struct dhcp_settings *dhcpset =
container_of ( settings, struct dhcp_settings, settings );
return dhcppkt_store ( &dhcpset->dhcppkt, setting->tag, data, len );
}
/**
* Fetch value of DHCP setting
*
* @v settings Settings block, or NULL to search all blocks
* @v setting Setting to fetch
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*/
static int dhcpset_fetch ( struct settings *settings, struct setting *setting,
void *data, size_t len ) {
struct dhcp_settings *dhcpset =
container_of ( settings, struct dhcp_settings, settings );
return dhcppkt_fetch ( &dhcpset->dhcppkt, setting->tag, data, len );
}
/** DHCP settings operations */
static struct settings_operations dhcpset_settings_operations = {
.store = dhcpset_store,
.fetch = dhcpset_fetch,
};
/**
* Create DHCP setting block
*
* @v dhcphdr DHCP packet
* @v len Length of DHCP packet
* @ret dhcpset DHCP settings block
*/
static struct dhcp_settings * dhcpset_create ( const struct dhcphdr *dhcphdr,
size_t len ) {
struct dhcp_settings *dhcpset;
void *data;
dhcpset = zalloc ( sizeof ( *dhcpset ) + len );
if ( dhcpset ) {
data = ( ( ( void * ) dhcpset ) + sizeof ( *dhcpset ) );
memcpy ( data, dhcphdr, len );
dhcppkt_init ( &dhcpset->dhcppkt, data, len );
settings_init ( &dhcpset->settings,
&dhcpset_settings_operations, &dhcpset->refcnt,
DHCP_SETTINGS_NAME, 0 );
}
return dhcpset;
}
/** 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 session
*
*/
/** DHCP session states */
enum dhcp_session_state {
/** Sending DHCPDISCOVERs, collecting DHCPOFFERs and ProxyDHCPOFFERs */
DHCP_STATE_DISCOVER = 0,
/** Sending DHCPREQUESTs, waiting for DHCPACK */
DHCP_STATE_REQUEST,
/** Sending ProxyDHCPREQUESTs, waiting for ProxyDHCPACK */
DHCP_STATE_PROXYREQUEST,
/** Sending BootServerDHCPREQUESTs, waiting for BootServerDHCPACK */
DHCP_STATE_BSREQUEST,
};
/**
* Name a DHCP session state
*
* @v state DHCP session state
* @ret string DHCP session state name
*/
static inline const char * dhcp_state_name ( enum dhcp_session_state state ) {
switch ( state ) {
case DHCP_STATE_DISCOVER: return "DHCPDISCOVER";
case DHCP_STATE_REQUEST: return "DHCPREQUEST";
case DHCP_STATE_PROXYREQUEST: return "ProxyDHCPREQUEST";
case DHCP_STATE_BSREQUEST: return "BootServerREQUEST";
default: return "<invalid>";
}
}
/** 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;
/** State of the session
*
* This is a value for the @c DHCP_MESSAGE_TYPE option
* (e.g. @c DHCPDISCOVER).
*/
enum dhcp_session_state state;
/** DHCPOFFER obtained during DHCPDISCOVER */
struct dhcp_settings *dhcpoffer;
/** ProxyDHCPOFFER obtained during DHCPDISCOVER */
struct dhcp_settings *proxydhcpoffer;
/** DHCPACK obtained during DHCPREQUEST */
struct dhcp_settings *dhcpack;
/** ProxyDHCPACK obtained during ProxyDHCPREQUEST */
struct dhcp_settings *proxydhcpack;
/** BootServerDHCPACK obtained during BootServerDHCPREQUEST */
struct dhcp_settings *bsdhcpack;
/** Retransmission timer */
struct retry_timer timer;
/** 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 );
dhcpset_put ( dhcp->dhcpoffer );
dhcpset_put ( dhcp->proxydhcpoffer );
dhcpset_put ( dhcp->dhcpack );
dhcpset_put ( dhcp->proxydhcpack );
dhcpset_put ( dhcp->bsdhcpack );
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 );
}
/****************************************************************************
*
* Data transfer interface
*
*/
/**
* 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 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 fills out a @c
* dhcp_packet structure.
*/
int dhcp_create_packet ( struct dhcp_packet *dhcppkt,
struct net_device *netdev, uint8_t msgtype,
struct dhcp_options *options,
void *data, size_t max_len ) {
struct dhcphdr *dhcphdr = data;
size_t options_len;
unsigned int hlen;
int rc;
/* Sanity check */
options_len = ( options ? options->len : 0 );
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];
/* If hardware length exceeds the chaddr field length, don't
* use the chaddr field. This is as per RFC4390.
*/
hlen = netdev->ll_protocol->ll_addr_len;
if ( hlen > sizeof ( dhcphdr->chaddr ) ) {
hlen = 0;
dhcphdr->flags = htons ( BOOTP_FL_BROADCAST );
}
dhcphdr->hlen = hlen;
memcpy ( dhcphdr->chaddr, netdev->ll_addr, hlen );
memcpy ( dhcphdr->options, options->data, 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, if applicable
* @v server Server identifier, if applicable
* @v requested_ip Requested address, if applicable
* @v menu_item PXE menu item, if applicable
* @v data Buffer for DHCP packet
* @v max_len Size of DHCP packet buffer
* @ret rc Return status code
*/
int dhcp_create_request ( struct dhcp_packet *dhcppkt,
struct net_device *netdev, unsigned int msgtype,
struct in_addr ciaddr, struct in_addr server,
struct in_addr requested_ip,
struct dhcp_pxe_boot_menu_item *menu_item,
void *data, size_t max_len ) {
struct device_description *desc = &netdev->dev->desc;
struct dhcp_netdev_desc dhcp_desc;
struct dhcp_client_id client_id;
struct dhcp_client_uuid client_uuid;
size_t dhcp_features_len;
size_t ll_addr_len;
int rc;
/* Create DHCP packet */
if ( ( rc = dhcp_create_packet ( dhcppkt, netdev, msgtype,
&dhcp_request_options, 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;
/* Set server ID, if present */
if ( server.s_addr &&
( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
&server, sizeof ( server ) ) ) != 0 ) ) {
DBG ( "DHCP could not set server ID: %s\n",
strerror ( rc ) );
return rc;
}
/* Set requested IP address, if present */
if ( requested_ip.s_addr &&
( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS,
&requested_ip,
sizeof ( requested_ip ) ) ) != 0 ) ) {
DBG ( "DHCP could not set requested address: %s\n",
strerror ( rc ) );
return rc;
}
/* Add options to identify the feature list */
dhcp_features_len = ( dhcp_features_end - 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 */
dhcp_desc.type = desc->bus_type;
dhcp_desc.vendor = htons ( desc->vendor );
dhcp_desc.device = htons ( desc->device );
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 ( ( rc = 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;
}
}
/* Set PXE boot menu item, if present */
if ( menu_item && menu_item->type &&
( ( rc = dhcppkt_store ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM,
menu_item,
sizeof ( *menu_item ) ) ) != 0 ) ) {
DBG ( "DHCP could not set PXE menu item: %s\n",
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Transmit DHCP request
*
* @v dhcp DHCP session
* @ret rc Return status code
*/
static int dhcp_tx ( struct dhcp_session *dhcp ) {
static struct sockaddr_in dest = {
.sin_family = AF_INET,
.sin_port = htons ( PROXYDHCP_PORT ),
};
static struct sockaddr_in src = {
.sin_family = AF_INET,
.sin_port = htons ( BOOTPC_PORT ),
};
struct xfer_metadata meta = {
.netdev = dhcp->netdev,
};
struct io_buffer *iobuf;
struct dhcp_packet dhcppkt;
struct in_addr ciaddr = { 0 };
struct in_addr server = { 0 };
struct in_addr requested_ip = { 0 };
struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 };
unsigned int msgtype;
int rc;
/* Start retry timer. Do this first so that failures to
* transmit will be retried.
*/
start_timer ( &dhcp->timer );
/* Determine packet contents based on current state */
switch ( dhcp->state ) {
case DHCP_STATE_DISCOVER:
msgtype = DHCPDISCOVER;
break;
case DHCP_STATE_REQUEST:
assert ( dhcp->dhcpoffer );
msgtype = DHCPREQUEST;
dhcppkt_fetch ( &dhcp->dhcpoffer->dhcppkt,
DHCP_SERVER_IDENTIFIER, &server,
sizeof ( server ) );
requested_ip = dhcp->dhcpoffer->dhcppkt.dhcphdr->yiaddr;
break;
case DHCP_STATE_PROXYREQUEST:
assert ( dhcp->dhcpoffer );
assert ( dhcp->proxydhcpoffer );
assert ( dhcp->dhcpack );
msgtype = DHCPREQUEST;
ciaddr = dhcp->dhcpoffer->dhcppkt.dhcphdr->yiaddr;
dhcppkt_fetch ( &dhcp->proxydhcpoffer->dhcppkt,
DHCP_SERVER_IDENTIFIER, &dest.sin_addr,
sizeof ( dest.sin_addr ) );
meta.dest = ( struct sockaddr * ) &dest;
server = dest.sin_addr;
assert ( dest.sin_addr.s_addr );
assert ( ciaddr.s_addr );
break;
case DHCP_STATE_BSREQUEST:
assert ( dhcp->dhcpoffer );
assert ( dhcp->proxydhcpoffer );
assert ( dhcp->dhcpack );
assert ( dhcp->proxydhcpack );
msgtype = DHCPREQUEST;
ciaddr = dhcp->dhcpoffer->dhcppkt.dhcphdr->yiaddr;
dhcppkt_fetch ( &dhcp->proxydhcpack->dhcppkt,
DHCP_PXE_BOOT_SERVER_MCAST,
&dest.sin_addr, sizeof ( dest.sin_addr ) );
meta.dest = ( struct sockaddr * ) &dest;
dhcppkt_fetch ( &dhcp->proxydhcpack->dhcppkt,
DHCP_PXE_BOOT_MENU, &menu_item.type,
sizeof ( menu_item.type ) );
assert ( dest.sin_addr.s_addr );
assert ( menu_item.type );
assert ( ciaddr.s_addr );
break;
default:
assert ( 0 );
return -EINVAL;
}
DBGC ( dhcp, "DHCP %p %s", dhcp, dhcp_msgtype_name ( msgtype ) );
if ( server.s_addr )
DBGC ( dhcp, " to %s", inet_ntoa ( server ) );
if ( meta.dest ) {
if ( dest.sin_addr.s_addr == server.s_addr ) {
DBGC ( dhcp, ":%d (unicast)",
ntohs ( dest.sin_port ) );
} else {
DBGC ( dhcp, " via %s:%d", inet_ntoa ( dest.sin_addr ),
ntohs ( dest.sin_port ) );
}
} else {
DBGC ( dhcp, " (broadcast)" );
}
if ( requested_ip.s_addr )
DBGC ( dhcp, " for %s", inet_ntoa ( requested_ip ) );
if ( menu_item.type )
DBGC ( dhcp, " for item %04x", ntohs ( menu_item.type ) );
DBGC ( dhcp, "\n" );
/* Allocate buffer for packet */
iobuf = xfer_alloc_iob ( &dhcp->xfer, DHCP_MIN_LEN );
if ( ! iobuf )
return -ENOMEM;
/* Create DHCP packet in temporary buffer */
if ( ( rc = dhcp_create_request ( &dhcppkt, dhcp->netdev, msgtype,
ciaddr, server, requested_ip,
&menu_item, iobuf->data,
iob_tailroom ( iobuf ) ) ) != 0 ) {
DBGC ( dhcp, "DHCP %p could not construct DHCP request: %s\n",
dhcp, strerror ( rc ) );
goto done;
}
/* Explicitly specify source address, if available. */
if ( ciaddr.s_addr ) {
src.sin_addr = ciaddr;
meta.src = ( struct sockaddr * ) &src;
}
/* Transmit the packet */
iob_put ( iobuf, dhcppkt.len );
rc = xfer_deliver_iob_meta ( &dhcp->xfer, iobuf, &meta );
iobuf = NULL;
if ( rc != 0 ) {
DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n",
dhcp, strerror ( rc ) );
goto done;
}
done:
free_iob ( iobuf );
return 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,
enum dhcp_session_state state ) {
DBGC ( dhcp, "DHCP %p entering %s state\n",
dhcp, dhcp_state_name ( state ) );
dhcp->state = state;
dhcp->start = currticks();
dhcp->timer.min_timeout = 0;
start_timer_nodelay ( &dhcp->timer );
}
/**
* Transition to next DHCP state
*
* @v dhcp DHCP session
*/
static void dhcp_next_state ( struct dhcp_session *dhcp ) {
struct in_addr bs_mcast = { 0 };
switch ( dhcp->state ) {
case DHCP_STATE_DISCOVER:
dhcp_set_state ( dhcp, DHCP_STATE_REQUEST );
break;
case DHCP_STATE_REQUEST:
if ( dhcp->proxydhcpoffer ) {
/* Store DHCPACK as ProxyDHCPACK. This
* handles the case in which the DHCP server
* itself responds with "PXEClient" and PXE
* options but there is no actual ProxyDHCP
* server resident on the machine.
*/
dhcp->proxydhcpack = dhcpset_get ( dhcp->dhcpack );
dhcp_set_state ( dhcp, DHCP_STATE_PROXYREQUEST );
break;
}
/* Fall through */
case DHCP_STATE_PROXYREQUEST:
if ( dhcp->proxydhcpack ) {
dhcppkt_fetch ( &dhcp->proxydhcpack->dhcppkt,
DHCP_PXE_BOOT_SERVER_MCAST,
&bs_mcast, sizeof ( bs_mcast ) );
if ( bs_mcast.s_addr ) {
dhcp_set_state ( dhcp, DHCP_STATE_BSREQUEST );
break;
}
}
/* Fall through */
case DHCP_STATE_BSREQUEST:
dhcp_finished ( dhcp, 0 );
break;
default:
assert ( 0 );
return;
}
}
/**
* Store received DHCPOFFER
*
* @v dhcp DHCP session
* @v dhcpoffer Received DHCPOFFER
* @v stored_dhcpoffer Location to store DHCPOFFER
*
* The DHCPOFFER will be stored in place of the existing stored
* DHCPOFFER if its priority is equal to or greater than the stored
* DHCPOFFER.
*/
static void dhcp_store_dhcpoffer ( struct dhcp_session *dhcp,
struct dhcp_settings *dhcpoffer,
struct dhcp_settings **stored_dhcpoffer ) {
uint8_t stored_priority = 0;
uint8_t priority = 0;
/* Get priorities of the two DHCPOFFERs */
if ( *stored_dhcpoffer ) {
dhcppkt_fetch ( &(*stored_dhcpoffer)->dhcppkt,
DHCP_EB_PRIORITY, &stored_priority,
sizeof ( stored_priority ) );
}
dhcppkt_fetch ( &dhcpoffer->dhcppkt, DHCP_EB_PRIORITY, &priority,
sizeof ( priority ) );
/* Replace stored offer only if priority is equal or greater */
if ( priority >= stored_priority ) {
if ( *stored_dhcpoffer ) {
DBGC ( dhcp, "DHCP %p stored DHCPOFFER %p discarded\n",
dhcp, *stored_dhcpoffer );
}
DBGC ( dhcp, "DHCP %p DHCPOFFER %p stored\n",
dhcp, dhcpoffer );
dhcpset_put ( *stored_dhcpoffer );
*stored_dhcpoffer = dhcpset_get ( dhcpoffer );
}
}
/**
* Handle received DHCPOFFER
*
* @v dhcp DHCP session
* @v dhcpoffer Received DHCPOFFER
*/
static void dhcp_rx_dhcpoffer ( struct dhcp_session *dhcp,
struct dhcp_settings *dhcpoffer ) {
struct in_addr server_id = { 0 };
char vci[9]; /* "PXEClient" */
int len;
uint8_t ignore_proxy = 0;
unsigned long elapsed;
/* Check for presence of DHCP server ID */
if ( dhcppkt_fetch ( &dhcpoffer->dhcppkt, DHCP_SERVER_IDENTIFIER,
&server_id, sizeof ( server_id ) )
!= sizeof ( server_id ) ) {
DBGC ( dhcp, "DHCP %p DHCPOFFER %p missing server ID\n",
dhcp, dhcpoffer );
/* Could be a valid BOOTP offer; do not abort processing */
}
/* If there is an IP address, it's a normal DHCPOFFER */
if ( dhcpoffer->dhcppkt.dhcphdr->yiaddr.s_addr != 0 ) {
DBGC ( dhcp, "DHCP %p DHCPOFFER %p from %s",
dhcp, dhcpoffer, inet_ntoa ( server_id ) );
DBGC ( dhcp, " has IP %s\n",
inet_ntoa ( dhcpoffer->dhcppkt.dhcphdr->yiaddr ) );
dhcp_store_dhcpoffer ( dhcp, dhcpoffer, &dhcp->dhcpoffer );
}
/* If there is a "PXEClient" vendor class ID, it's a
* ProxyDHCPOFFER. Note that it could be both a normal
* DHCPOFFER and a ProxyDHCPOFFER.
*/
len = dhcppkt_fetch ( &dhcpoffer->dhcppkt, DHCP_VENDOR_CLASS_ID,
vci, sizeof ( vci ) );
if ( ( server_id.s_addr != 0 ) &&
( len >= ( int ) sizeof ( vci ) ) &&
( strncmp ( "PXEClient", vci, sizeof ( vci ) ) == 0 ) ) {
DBGC ( dhcp, "DHCP %p DHCPOFFER %p from %s is a "
"ProxyDHCPOFFER\n",
dhcp, dhcpoffer, inet_ntoa ( server_id ) );
dhcp_store_dhcpoffer ( dhcp, dhcpoffer,
&dhcp->proxydhcpoffer );
}
/* We can transition to making the DHCPREQUEST when we have a
* valid DHCPOFFER, and either:
*
* o The DHCPOFFER instructs us to not wait for ProxyDHCP, 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->dhcpoffer )
return;
/* If the DHCPOFFER instructs us to ignore ProxyDHCP, discard
* any ProxyDHCPOFFER
*/
dhcppkt_fetch ( &dhcp->dhcpoffer->dhcppkt, DHCP_EB_NO_PROXYDHCP,
&ignore_proxy, sizeof ( ignore_proxy ) );
if ( ignore_proxy && dhcp->proxydhcpoffer ) {
DBGC ( dhcp, "DHCP %p discarding ProxyDHCPOFFER\n", dhcp );
dhcpset_put ( dhcp->proxydhcpoffer );
dhcp->proxydhcpoffer = NULL;
}
/* If we can't yet transition to DHCPREQUEST, do nothing */
elapsed = ( currticks() - dhcp->start );
if ( ! ( ignore_proxy || dhcp->proxydhcpoffer ||
( elapsed > PROXYDHCP_WAIT_TIME ) ) )
return;
/* Transition to DHCPREQUEST */
dhcp_next_state ( dhcp );
}
/**
* Store received DHCPACK
*
* @v dhcp DHCP session
* @v dhcpack Received DHCPACK
*
* The DHCPACK will be registered as a settings block.
*/
static int dhcp_store_dhcpack ( struct dhcp_session *dhcp,
struct dhcp_settings *dhcpack,
struct settings *parent ) {
struct settings *settings = &dhcpack->settings;
struct settings *old_settings;
int rc;
/* Unregister any old settings obtained via DHCP */
if ( ( old_settings = find_child_settings ( parent, settings->name ) ))
unregister_settings ( old_settings );
/* Register new settings */
if ( ( rc = register_settings ( settings, parent ) ) != 0 ) {
DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
dhcp, strerror ( rc ) );
dhcp_finished ( dhcp, rc ); /* This is a fatal error */
return rc;
}
return 0;
}
/**
* Handle received DHCPACK
*
* @v dhcp DHCP session
* @v dhcpack Received DHCPACK
*/
static void dhcp_rx_dhcpack ( struct dhcp_session *dhcp,
struct dhcp_settings *dhcpack ) {
struct settings *parent;
struct in_addr offer_server_id = { 0 };
struct in_addr ack_server_id = { 0 };
int rc;
/* Verify server ID matches */
assert ( dhcp->dhcpoffer != NULL );
dhcppkt_fetch ( &dhcp->dhcpoffer->dhcppkt, DHCP_SERVER_IDENTIFIER,
&offer_server_id, sizeof ( offer_server_id ) );
dhcppkt_fetch ( &dhcpack->dhcppkt, DHCP_SERVER_IDENTIFIER,
&ack_server_id, sizeof ( ack_server_id ) );
if ( offer_server_id.s_addr != ack_server_id.s_addr ) {
DBGC ( dhcp, "DHCP %p ignoring DHCPACK with wrong server ID "
"%s\n", dhcp, inet_ntoa ( ack_server_id ) );
return;
}
/* Record DHCPACK */
assert ( dhcp->dhcpack == NULL );
dhcp->dhcpack = dhcpset_get ( dhcpack );
/* Register settings */
parent = netdev_settings ( dhcp->netdev );
if ( ( rc = dhcp_store_dhcpack ( dhcp, dhcpack, parent ) ) != 0 )
return;
/* Transition to next state */
dhcp_next_state ( dhcp );
}
/**
* Handle received ProxyDHCPACK
*
* @v dhcp DHCP session
* @v proxydhcpack Received ProxyDHCPACK
*/
static void dhcp_rx_proxydhcpack ( struct dhcp_session *dhcp,
struct dhcp_settings *proxydhcpack ) {
struct in_addr offer_server_id = { 0 };
struct in_addr ack_server_id = { 0 };
int rc;
/* Verify server ID matches, if present */
assert ( dhcp->proxydhcpoffer != NULL );
if ( ( rc = dhcppkt_fetch ( &proxydhcpack->dhcppkt,
DHCP_SERVER_IDENTIFIER, &ack_server_id,
sizeof ( ack_server_id ) ) ) > 0 ) {
dhcppkt_fetch ( &dhcp->proxydhcpoffer->dhcppkt,
DHCP_SERVER_IDENTIFIER, &offer_server_id,
sizeof ( offer_server_id ) );
if ( offer_server_id.s_addr != ack_server_id.s_addr ) {
DBGC ( dhcp, "DHCP %p ignoring ProxyDHCPACK with "
"wrong server ID %s\n",
dhcp, inet_ntoa ( ack_server_id ) );
return;
}
}
/* Rename settings */
proxydhcpack->settings.name = PROXYDHCP_SETTINGS_NAME;
/* Record ProxyDHCPACK */
dhcpset_put ( dhcp->proxydhcpack );
dhcp->proxydhcpack = dhcpset_get ( proxydhcpack );
/* Register settings */
if ( ( rc = dhcp_store_dhcpack ( dhcp, proxydhcpack, NULL ) ) != 0 )
return;
/* Transition to next state */
dhcp_next_state ( dhcp );
}
/**
* Handle received BootServerDHCPACK
*
* @v dhcp DHCP session
* @v bsdhcpack Received BootServerDHCPACK
*/
static void dhcp_rx_bsdhcpack ( struct dhcp_session *dhcp,
struct dhcp_settings *bsdhcpack ) {
int rc;
/* Rename settings */
bsdhcpack->settings.name = BSDHCP_SETTINGS_NAME;
/* Record ProxyDHCPACK */
assert ( dhcp->bsdhcpack == NULL );
dhcp->bsdhcpack = dhcpset_get ( bsdhcpack );
/* Register settings */
if ( ( rc = dhcp_store_dhcpack ( dhcp, bsdhcpack, NULL ) ) != 0 )
return;
/* Transition to next state */
dhcp_next_state ( dhcp );
}
/**
* 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 *sin_src;
unsigned int src_port;
struct dhcp_settings *dhcpset;
struct dhcphdr *dhcphdr;
uint8_t msgtype = 0;
int rc = 0;
/* Sanity checks */
if ( ! meta ) {
DBGC ( dhcp, "DHCP %p received packet without metadata\n",
dhcp );
rc = -EINVAL;
goto err_no_meta;
}
if ( ! meta->src ) {
DBGC ( dhcp, "DHCP %p received packet without source port\n",
dhcp );
rc = -EINVAL;
goto err_no_src;
}
sin_src = ( struct sockaddr_in * ) meta->src;
src_port = sin_src->sin_port;
/* Convert packet into a DHCP settings block */
dhcpset = dhcpset_create ( iobuf->data, iob_len ( iobuf ) );
if ( ! dhcpset ) {
DBGC ( dhcp, "DHCP %p could not store DHCP packet\n", dhcp );
rc = -ENOMEM;
goto err_dhcpset_create;
}
dhcphdr = dhcpset->dhcppkt.dhcphdr;
/* Identify message type */
dhcppkt_fetch ( &dhcpset->dhcppkt, DHCP_MESSAGE_TYPE, &msgtype,
sizeof ( msgtype ) );
DBGC ( dhcp, "DHCP %p %s %p from %s:%d\n", dhcp,
dhcp_msgtype_name ( msgtype ), dhcpset,
inet_ntoa ( sin_src->sin_addr ), ntohs ( src_port ) );
/* Check for matching transaction ID */
if ( dhcphdr->xid != dhcp_xid ( dhcp->netdev ) ) {
DBGC ( dhcp, "DHCP %p %s %p has bad transaction ID\n",
dhcp, dhcp_msgtype_name ( msgtype ), dhcpset );
rc = -EINVAL;
goto err_xid;
};
/* Handle packet based on current state */
switch ( dhcp->state ) {
case DHCP_STATE_DISCOVER:
if ( ( ( msgtype == DHCPOFFER ) || ( msgtype == DHCPNONE ) ) &&
( src_port == htons ( BOOTPS_PORT ) ) )
dhcp_rx_dhcpoffer ( dhcp, dhcpset );
break;
case DHCP_STATE_REQUEST:
if ( ( ( msgtype == DHCPACK ) || ( msgtype == DHCPNONE ) ) &&
( src_port == htons ( BOOTPS_PORT ) ) )
dhcp_rx_dhcpack ( dhcp, dhcpset );
break;
case DHCP_STATE_PROXYREQUEST:
if ( ( msgtype == DHCPACK ) &&
( src_port == htons ( PROXYDHCP_PORT ) ) )
dhcp_rx_proxydhcpack ( dhcp, dhcpset );
break;
case DHCP_STATE_BSREQUEST:
if ( ( msgtype == DHCPACK ) &&
( src_port == htons ( PROXYDHCP_PORT ) ) )
dhcp_rx_bsdhcpack ( dhcp, dhcpset );
break;
default:
assert ( 0 );
break;
}
err_xid:
dhcpset_put ( dhcpset );
err_dhcpset_create:
err_no_src:
err_no_meta:
free_iob ( iobuf );
return rc;
}
/** DHCP data transfer interface operations */
static struct xfer_interface_operations dhcp_xfer_operations = {
.close = ignore_xfer_close,
.vredirect = xfer_vopen,
.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 );
unsigned long elapsed = ( currticks() - dhcp->start );
/* If we have failed, terminate DHCP */
if ( fail ) {
dhcp_finished ( dhcp, -ETIMEDOUT );
return;
}
/* Give up waiting for ProxyDHCP before we reach the failure point */
if ( dhcp->dhcpoffer && ( elapsed > PROXYDHCP_WAIT_TIME ) ) {
dhcp_next_state ( dhcp );
return;
}
/* Otherwise, retransmit current packet */
dhcp_tx ( 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,
};
/****************************************************************************
*
* Instantiator
*
*/
/**
* Start DHCP on a network device
*
* @v job Job control interface
* @v netdev Network device
* @v register_options DHCP option block registration routine
* @ret rc Return status code
*
* Starts DHCP on the specified network device. If successful, the @c
* register_options() routine will be called with the acquired
* options.
*/
int start_dhcp ( struct job_interface *job, struct net_device *netdev ) {
static struct sockaddr_in server = {
.sin_family = AF_INET,
.sin_addr.s_addr = INADDR_BROADCAST,
.sin_port = htons ( BOOTPS_PORT ),
};
static struct sockaddr_in client = {
.sin_family = AF_INET,
.sin_port = htons ( BOOTPC_PORT ),
};
struct dhcp_session *dhcp;
int rc;
/* 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->timer.expired = dhcp_timer_expired;
dhcp->timer.min_timeout = DHCP_MIN_TIMEOUT;
dhcp->timer.max_timeout = DHCP_MAX_TIMEOUT;
dhcp->start = currticks();
/* Instantiate child objects and attach to our interfaces */
if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM,
( struct sockaddr * ) &server,
( struct sockaddr * ) &client ) ) != 0 )
goto err;
/* Start timer to initiate initial DHCPREQUEST */
start_timer_nodelay ( &dhcp->timer );
/* 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;
}