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android / platform / external / syslinux / 76d05dc695b06c4e987bb8078f78032441e1430c / . / gpxe / src / net / udp / dhcp.c
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/*
* Copyright (C) 2006 Michael Brown <[email protected]>.
*
* 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;
}