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dhcp.c
1587 lines (1392 loc) · 43.8 KB
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dhcp.c
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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <byteswap.h>
#include <ipxe/if_ether.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/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.