diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/net/udp/dhcp.c')
| -rw-r--r-- | contrib/syslinux-4.02/gpxe/src/net/udp/dhcp.c | 1587 |
1 files changed, 1587 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/net/udp/dhcp.c b/contrib/syslinux-4.02/gpxe/src/net/udp/dhcp.c new file mode 100644 index 0000000..ce2c820 --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/net/udp/dhcp.c @@ -0,0 +1,1587 @@ +/* + * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <string.h> +#include <stdlib.h> +#include <stdio.h> +#include <ctype.h> +#include <errno.h> +#include <assert.h> +#include <byteswap.h> +#include <gpxe/if_ether.h> +#include <gpxe/netdevice.h> +#include <gpxe/device.h> +#include <gpxe/xfer.h> +#include <gpxe/open.h> +#include <gpxe/job.h> +#include <gpxe/retry.h> +#include <gpxe/tcpip.h> +#include <gpxe/ip.h> +#include <gpxe/uuid.h> +#include <gpxe/timer.h> +#include <gpxe/settings.h> +#include <gpxe/dhcp.h> +#include <gpxe/dhcpopts.h> +#include <gpxe/dhcppkt.h> +#include <gpxe/features.h> + +/** @file + * + * Dynamic Host Configuration Protocol + * + */ + +struct dhcp_session; +static int dhcp_tx ( struct dhcp_session *dhcp ); + +/** + * DHCP operation types + * + * This table maps from DHCP message types (i.e. values of the @c + * DHCP_MESSAGE_TYPE option) to values of the "op" field within a DHCP + * packet. + */ +static const uint8_t dhcp_op[] = { + [DHCPDISCOVER] = BOOTP_REQUEST, + [DHCPOFFER] = BOOTP_REPLY, + [DHCPREQUEST] = BOOTP_REQUEST, + [DHCPDECLINE] = BOOTP_REQUEST, + [DHCPACK] = BOOTP_REPLY, + [DHCPNAK] = BOOTP_REPLY, + [DHCPRELEASE] = BOOTP_REQUEST, + [DHCPINFORM] = BOOTP_REQUEST, +}; + +/** Raw option data for options common to all DHCP requests */ +static uint8_t dhcp_request_options_data[] = { + DHCP_MESSAGE_TYPE, DHCP_BYTE ( 0 ), + DHCP_MAX_MESSAGE_SIZE, + DHCP_WORD ( ETH_MAX_MTU - 20 /* IP header */ - 8 /* UDP header */ ), + DHCP_CLIENT_ARCHITECTURE, DHCP_WORD ( 0 ), + DHCP_CLIENT_NDI, DHCP_OPTION ( 1 /* UNDI */ , 2, 1 /* v2.1 */ ), + DHCP_VENDOR_CLASS_ID, + DHCP_STRING ( 'P', 'X', 'E', 'C', 'l', 'i', 'e', 'n', 't', ':', + 'A', 'r', 'c', 'h', ':', '0', '0', '0', '0', '0', ':', + 'U', 'N', 'D', 'I', ':', '0', '0', '2', '0', '0', '1' ), + DHCP_USER_CLASS_ID, + DHCP_STRING ( 'g', 'P', 'X', 'E' ), + DHCP_PARAMETER_REQUEST_LIST, + DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_DNS_SERVERS, + DHCP_LOG_SERVERS, DHCP_HOST_NAME, DHCP_DOMAIN_NAME, + DHCP_ROOT_PATH, DHCP_VENDOR_ENCAP, DHCP_VENDOR_CLASS_ID, + DHCP_TFTP_SERVER_NAME, DHCP_BOOTFILE_NAME, + DHCP_EB_ENCAP, DHCP_ISCSI_INITIATOR_IQN ), + DHCP_END +}; + +/** Version number feature */ +FEATURE_VERSION ( VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH ); + +/** DHCP server address setting */ +struct setting dhcp_server_setting __setting = { + .name = "dhcp-server", + .description = "DHCP server address", + .tag = DHCP_SERVER_IDENTIFIER, + .type = &setting_type_ipv4, +}; + +/** DHCP user class setting */ +struct setting user_class_setting __setting = { + .name = "user-class", + .description = "User class identifier", + .tag = DHCP_USER_CLASS_ID, + .type = &setting_type_string, +}; + +/** Use cached network settings */ +struct setting use_cached_setting __setting = { + .name = "use-cached", + .description = "Use cached network settings", + .tag = DHCP_EB_USE_CACHED, + .type = &setting_type_uint8, +}; + +/** + * Name a DHCP packet type + * + * @v msgtype DHCP message type + * @ret string DHCP mesasge type name + */ +static inline const char * dhcp_msgtype_name ( unsigned int msgtype ) { + switch ( msgtype ) { + case DHCPNONE: return "BOOTP"; /* Non-DHCP packet */ + case DHCPDISCOVER: return "DHCPDISCOVER"; + case DHCPOFFER: return "DHCPOFFER"; + case DHCPREQUEST: return "DHCPREQUEST"; + case DHCPDECLINE: return "DHCPDECLINE"; + case DHCPACK: return "DHCPACK"; + case DHCPNAK: return "DHCPNAK"; + case DHCPRELEASE: return "DHCPRELEASE"; + case DHCPINFORM: return "DHCPINFORM"; + default: return "DHCP<invalid>"; + } +} + +/** + * Calculate DHCP transaction ID for a network device + * + * @v netdev Network device + * @ret xid DHCP XID + * + * Extract the least significant bits of the hardware address for use + * as the transaction ID. + */ +static uint32_t dhcp_xid ( struct net_device *netdev ) { + uint32_t xid; + + memcpy ( &xid, ( netdev->ll_addr + netdev->ll_protocol->ll_addr_len + - sizeof ( xid ) ), sizeof ( xid ) ); + return xid; +} + +/**************************************************************************** + * + * DHCP session + * + */ + +struct dhcp_session; + +/** DHCP session state operations */ +struct dhcp_session_state { + /** State name */ + const char *name; + /** + * Construct transmitted packet + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer Destination address + */ + int ( * tx ) ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer ); + /** Handle received packet + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ + void ( * rx ) ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, + uint8_t msgtype, struct in_addr server_id ); + /** Handle timer expiry + * + * @v dhcp DHCP session + */ + void ( * expired ) ( struct dhcp_session *dhcp ); + /** Transmitted message type */ + uint8_t tx_msgtype; + /** Apply minimum timeout */ + uint8_t apply_min_timeout; +}; + +static struct dhcp_session_state dhcp_state_discover; +static struct dhcp_session_state dhcp_state_request; +static struct dhcp_session_state dhcp_state_proxy; +static struct dhcp_session_state dhcp_state_pxebs; + +/** DHCP offer is valid for IP lease */ +#define DHCP_OFFER_IP 1 + +/** DHCP offer is valid for PXE options */ +#define DHCP_OFFER_PXE 2 + +/** A DHCP offer */ +struct dhcp_offer { + /** IP address of server granting offer */ + struct in_addr server; + + /** IP address being offered, or 0.0.0.0 for a pure proxy */ + struct in_addr ip; + + /** DHCP packet containing PXE options; NULL if missing or proxied */ + struct dhcp_packet *pxe; + + /** Valid uses for this offer, a combination of DHCP_OFFER bits */ + uint8_t valid; + + /** Priority of this offer */ + int8_t priority; + + /** Whether to ignore PXE DHCP extensions */ + uint8_t no_pxedhcp; +}; + +/** Maximum number of DHCP offers to queue */ +#define DHCP_MAX_OFFERS 6 + +/** A DHCP session */ +struct dhcp_session { + /** Reference counter */ + struct refcnt refcnt; + /** Job control interface */ + struct job_interface job; + /** Data transfer interface */ + struct xfer_interface xfer; + + /** Network device being configured */ + struct net_device *netdev; + /** Local socket address */ + struct sockaddr_in local; + /** State of the session */ + struct dhcp_session_state *state; + + /** PXE Boot Server type */ + uint16_t pxe_type; + /** List of PXE Boot Servers to attempt */ + struct in_addr *pxe_attempt; + /** List of PXE Boot Servers to accept */ + struct in_addr *pxe_accept; + + /** Retransmission timer */ + struct retry_timer timer; + /** Start time of the current state (in ticks) */ + unsigned long start; + + /** DHCP offer just requested */ + struct dhcp_offer *current_offer; + /** List of DHCP offers received */ + struct dhcp_offer offers[DHCP_MAX_OFFERS]; +}; + +/** + * Free DHCP session + * + * @v refcnt Reference counter + */ +static void dhcp_free ( struct refcnt *refcnt ) { + struct dhcp_session *dhcp = + container_of ( refcnt, struct dhcp_session, refcnt ); + int i; + + for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) { + if ( dhcp->offers[i].pxe ) + dhcppkt_put ( dhcp->offers[i].pxe ); + } + + netdev_put ( dhcp->netdev ); + free ( dhcp ); +} + +/** + * Mark DHCP session as complete + * + * @v dhcp DHCP session + * @v rc Return status code + */ +static void dhcp_finished ( struct dhcp_session *dhcp, int rc ) { + + /* Block futher incoming messages */ + job_nullify ( &dhcp->job ); + xfer_nullify ( &dhcp->xfer ); + + /* Stop retry timer */ + stop_timer ( &dhcp->timer ); + + /* Free resources and close interfaces */ + xfer_close ( &dhcp->xfer, rc ); + job_done ( &dhcp->job, rc ); +} + +/** + * Transition to new DHCP session state + * + * @v dhcp DHCP session + * @v state New session state + */ +static void dhcp_set_state ( struct dhcp_session *dhcp, + struct dhcp_session_state *state ) { + + DBGC ( dhcp, "DHCP %p entering %s state\n", dhcp, state->name ); + dhcp->state = state; + dhcp->start = currticks(); + stop_timer ( &dhcp->timer ); + dhcp->timer.min_timeout = + ( state->apply_min_timeout ? DHCP_MIN_TIMEOUT : 0 ); + dhcp->timer.max_timeout = DHCP_MAX_TIMEOUT; + start_timer_nodelay ( &dhcp->timer ); +} + +/** + * Determine next DHCP offer to try + * + * @v dhcp DHCP session + * @v type DHCP offer type + * @ret offer Next DHCP offer to try + * + * Offers are ranked by priority, then by completeness (combined + * IP+PXE are tried before @a type alone), then by order of receipt. + */ +static struct dhcp_offer * dhcp_next_offer ( struct dhcp_session *dhcp, + uint8_t type ) { + + struct dhcp_offer *offer; + struct dhcp_offer *best = NULL; + + for ( offer = dhcp->offers ; offer < dhcp->offers + DHCP_MAX_OFFERS ; + offer++ ) { + if ( ( offer->valid & type ) && + ( ( best == NULL ) || + ( offer->priority > best->priority ) || + ( ( offer->priority == best->priority ) && + ( offer->valid & ~best->valid ) ) ) ) + best = offer; + } + + return best; +} + +/**************************************************************************** + * + * DHCP state machine + * + */ + +/** + * Construct transmitted packet for DHCP discovery + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer Destination address + */ +static int dhcp_discovery_tx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt __unused, + struct sockaddr_in *peer ) { + + DBGC ( dhcp, "DHCP %p DHCPDISCOVER\n", dhcp ); + + /* Set server address */ + peer->sin_addr.s_addr = INADDR_BROADCAST; + peer->sin_port = htons ( BOOTPS_PORT ); + + return 0; +} + +/** + * Handle received DHCPOFFER during any state + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ +static void dhcp_rx_offer ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, uint8_t msgtype, + struct in_addr server_id ) { + char vci[9]; /* "PXEClient" */ + int vci_len; + int has_pxeclient; + int pxeopts_len; + int has_pxeopts; + struct dhcp_offer *offer; + int i; + + DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, + dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), + ntohs ( peer->sin_port ) ); + if ( server_id.s_addr != peer->sin_addr.s_addr ) + DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) ); + + /* Identify offered IP address */ + if ( dhcppkt->dhcphdr->yiaddr.s_addr ) + DBGC ( dhcp, " for %s", inet_ntoa ( dhcppkt->dhcphdr->yiaddr )); + + /* Enqueue an offer to be filled in */ + for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) { + if ( dhcp->offers[i].server.s_addr == server_id.s_addr ) { + DBGC ( dhcp, " dup\n" ); + return; + } + + if ( ! dhcp->offers[i].valid ) + break; + } + if ( i == DHCP_MAX_OFFERS ) { + DBGC ( dhcp, " dropped\n" ); + return; + } + + offer = &dhcp->offers[i]; + offer->server = server_id; + offer->ip = dhcppkt->dhcphdr->yiaddr; + + /* Identify "PXEClient" vendor class */ + vci_len = dhcppkt_fetch ( dhcppkt, DHCP_VENDOR_CLASS_ID, + vci, sizeof ( vci ) ); + has_pxeclient = ( ( vci_len >= ( int ) sizeof ( vci ) ) && + ( strncmp ( "PXEClient", vci, sizeof (vci) ) == 0 )); + + /* Identify presence of PXE-specific options */ + pxeopts_len = dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU, NULL, 0 ); + has_pxeopts = ( pxeopts_len >= 0 ); + if ( has_pxeclient ) + DBGC ( dhcp, "%s", ( has_pxeopts ? " pxe" : " proxy" ) ); + + if ( has_pxeclient && has_pxeopts ) { + /* Save reference to packet for future use */ + if ( offer->pxe ) + dhcppkt_put ( offer->pxe ); + offer->pxe = dhcppkt_get ( dhcppkt ); + } + + /* Identify priority */ + dhcppkt_fetch ( dhcppkt, DHCP_EB_PRIORITY, &offer->priority, + sizeof ( offer->priority ) ); + if ( offer->priority ) + DBGC ( dhcp, " pri %d", offer->priority ); + + /* Identify ignore-PXE flag */ + dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &offer->no_pxedhcp, + sizeof ( offer->no_pxedhcp ) ); + if ( offer->no_pxedhcp ) + DBGC ( dhcp, " nopxe" ); + DBGC ( dhcp, "\n" ); + + /* Determine roles this offer can fill */ + if ( offer->ip.s_addr && + ( peer->sin_port == htons ( BOOTPS_PORT ) ) && + ( ( msgtype == DHCPOFFER ) || ( ! msgtype /* BOOTP */ ) ) ) + offer->valid |= DHCP_OFFER_IP; + + if ( has_pxeclient && ( msgtype == DHCPOFFER ) ) + offer->valid |= DHCP_OFFER_PXE; +} + +/** + * Handle received packet during DHCP discovery + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ +static void dhcp_discovery_rx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, uint8_t msgtype, + struct in_addr server_id ) { + unsigned long elapsed; + struct dhcp_offer *ip_offer; + + dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id ); + + /* We can exit the discovery state when we have a valid + * DHCPOFFER, and either: + * + * o The DHCPOFFER instructs us to ignore ProxyDHCPOFFERs, or + * o We have a valid ProxyDHCPOFFER, or + * o We have allowed sufficient time for ProxyDHCPOFFERs. + */ + + /* If we don't yet have a DHCPOFFER, do nothing */ + ip_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP ); + if ( ! ip_offer ) + return; + + /* If we can't yet transition to DHCPREQUEST, do nothing */ + elapsed = ( currticks() - dhcp->start ); + if ( ! ( ip_offer->no_pxedhcp || + dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) || + ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) ) + return; + + /* Transition to DHCPREQUEST */ + dhcp_set_state ( dhcp, &dhcp_state_request ); +} + +/** + * Handle timer expiry during DHCP discovery + * + * @v dhcp DHCP session + */ +static void dhcp_discovery_expired ( struct dhcp_session *dhcp ) { + unsigned long elapsed = ( currticks() - dhcp->start ); + + /* Give up waiting for ProxyDHCP before we reach the failure point */ + if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) && + ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) { + dhcp_set_state ( dhcp, &dhcp_state_request ); + return; + } + + /* Otherwise, retransmit current packet */ + dhcp_tx ( dhcp ); +} + +/** DHCP discovery state operations */ +static struct dhcp_session_state dhcp_state_discover = { + .name = "discovery", + .tx = dhcp_discovery_tx, + .rx = dhcp_discovery_rx, + .expired = dhcp_discovery_expired, + .tx_msgtype = DHCPDISCOVER, + .apply_min_timeout = 1, +}; + +/** + * Construct transmitted packet for DHCP request + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer Destination address + */ +static int dhcp_request_tx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer ) { + int rc; + struct dhcp_offer *offer; + + offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP ); + + DBGC ( dhcp, "DHCP %p DHCPREQUEST to %s:%d", + dhcp, inet_ntoa ( offer->server ), BOOTPS_PORT ); + DBGC ( dhcp, " for %s\n", inet_ntoa ( offer->ip ) ); + + /* Set server ID */ + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER, + &offer->server, + sizeof ( offer->server ) ) ) != 0 ) + return rc; + + /* Set requested IP address */ + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS, + &offer->ip, sizeof ( offer->ip ) ) ) != 0 ) + return rc; + + /* Set server address */ + peer->sin_addr.s_addr = INADDR_BROADCAST; + peer->sin_port = htons ( BOOTPS_PORT ); + + return 0; +} + +/** + * Handle received packet during DHCP request + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ +static void dhcp_request_rx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, uint8_t msgtype, + struct in_addr server_id ) { + struct in_addr ip; + struct settings *parent; + int rc; + struct dhcp_offer *pxe_offer; + + if ( msgtype == DHCPOFFER ) { + dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id ); + if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) != + dhcp->current_offer ) { + /* Restart due to higher-priority offer received */ + DBGC ( dhcp, "DHCP %p re-requesting\n", dhcp ); + dhcp_set_state ( dhcp, &dhcp_state_request ); + } + return; + } + + DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, + dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), + ntohs ( peer->sin_port ) ); + if ( server_id.s_addr != peer->sin_addr.s_addr ) + DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) ); + + /* Identify leased IP address */ + ip = dhcppkt->dhcphdr->yiaddr; + if ( ip.s_addr ) + DBGC ( dhcp, " for %s", inet_ntoa ( ip ) ); + DBGC ( dhcp, "\n" ); + + /* Filter out unacceptable responses */ + if ( peer->sin_port != htons ( BOOTPS_PORT ) ) + return; + if ( msgtype /* BOOTP */ && ( msgtype != DHCPACK ) ) + return; + if ( server_id.s_addr != dhcp->current_offer->server.s_addr ) + return; + + /* Record assigned address */ + dhcp->local.sin_addr = ip; + + /* Register settings */ + parent = netdev_settings ( dhcp->netdev ); + if ( ( rc = register_settings ( &dhcppkt->settings, parent ) ) != 0 ){ + DBGC ( dhcp, "DHCP %p could not register settings: %s\n", + dhcp, strerror ( rc ) ); + dhcp_finished ( dhcp, rc ); + return; + } + + /* Locate best source of PXE settings */ + pxe_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ); + + if ( ( ! pxe_offer ) || /* No PXE available */ + /* IP offer instructs us to ignore PXE */ + dhcp->current_offer->no_pxedhcp || + /* PXE settings already registered with IP offer */ + ( ( dhcp->current_offer == pxe_offer ) && ( pxe_offer->pxe ) ) ) { + + /* Terminate DHCP */ + dhcp_finished ( dhcp, 0 ); + + } else if ( pxe_offer->pxe ) { + /* Register PXE settings and terminate DHCP */ + pxe_offer->pxe->settings.name = PROXYDHCP_SETTINGS_NAME; + if ( ( rc = register_settings ( &pxe_offer->pxe->settings, + NULL ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not register settings: " + "%s\n", dhcp, strerror ( rc ) ); + } + dhcp_finished ( dhcp, rc ); + } else { + /* Start ProxyDHCP */ + dhcp_set_state ( dhcp, &dhcp_state_proxy ); + } +} + +/** + * Handle timer expiry during DHCP discovery + * + * @v dhcp DHCP session + */ +static void dhcp_request_expired ( struct dhcp_session *dhcp ) { + + /* Retransmit current packet */ + dhcp_tx ( dhcp ); +} + +/** DHCP request state operations */ +static struct dhcp_session_state dhcp_state_request = { + .name = "request", + .tx = dhcp_request_tx, + .rx = dhcp_request_rx, + .expired = dhcp_request_expired, + .tx_msgtype = DHCPREQUEST, + .apply_min_timeout = 0, +}; + +/** + * Construct transmitted packet for ProxyDHCP request + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer Destination address + */ +static int dhcp_proxy_tx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer ) { + int rc; + struct dhcp_offer *offer; + + offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ); + + DBGC ( dhcp, "DHCP %p ProxyDHCP REQUEST to %s:%d\n", dhcp, + inet_ntoa ( offer->server ), PXE_PORT ); + + /* Set server ID */ + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER, + &offer->server, + sizeof ( offer->server ) ) ) != 0 ) + return rc; + + /* Set server address */ + peer->sin_addr = offer->server; + peer->sin_port = htons ( PXE_PORT ); + + return 0; +} + +/** + * Handle received packet during ProxyDHCP request + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ +static void dhcp_proxy_rx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, uint8_t msgtype, + struct in_addr server_id ) { + int rc; + + /* Enqueue last-minute DHCPOFFERs for use in case of failure */ + if ( peer->sin_port == htons ( BOOTPS_PORT ) && + msgtype == DHCPOFFER ) { + dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id ); + return; + } + + DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, + dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), + ntohs ( peer->sin_port ) ); + if ( server_id.s_addr != peer->sin_addr.s_addr ) + DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) ); + DBGC ( dhcp, "\n" ); + + /* Filter out unacceptable responses */ + if ( peer->sin_port != htons ( PXE_PORT ) ) + return; + if ( msgtype != DHCPACK && msgtype != DHCPOFFER ) + return; + if ( server_id.s_addr /* Linux PXE server omits server ID */ && + ( server_id.s_addr != dhcp->current_offer->server.s_addr ) ) + return; + + /* Register settings */ + dhcppkt->settings.name = PROXYDHCP_SETTINGS_NAME; + if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not register settings: %s\n", + dhcp, strerror ( rc ) ); + dhcp_finished ( dhcp, rc ); + return; + } + + /* Terminate DHCP */ + dhcp_finished ( dhcp, 0 ); +} + +/** + * Handle timer expiry during ProxyDHCP request + * + * @v dhcp DHCP session + */ +static void dhcp_proxy_expired ( struct dhcp_session *dhcp ) { + unsigned long elapsed = ( currticks() - dhcp->start ); + + /* Give up waiting for ProxyDHCP before we reach the failure point */ + if ( elapsed > PROXYDHCP_MAX_TIMEOUT ) { + + /* Mark failed offer as unsuitable for ProxyDHCP */ + dhcp->current_offer->valid &= ~DHCP_OFFER_PXE; + + /* Prefer not to use only half of a PXE+IP offer if we + * have other offers available + */ + dhcp->current_offer->priority = -1; + + /* If we have any other PXE offers we can try, go back + * to DHCPREQUEST (since they might not be proxied + * offers, or might be coupled to a new IP address). + * We should probably DHCPRELEASE our old IP, but the + * standard does not require it. + */ + if ( dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) ) { + dhcp->local.sin_addr.s_addr = 0; + dhcp_set_state ( dhcp, &dhcp_state_request ); + return; + } + + /* No possibilities left; finish without PXE options */ + dhcp_finished ( dhcp, 0 ); + return; + } + + /* Retransmit current packet */ + dhcp_tx ( dhcp ); +} + +/** ProxyDHCP request state operations */ +static struct dhcp_session_state dhcp_state_proxy = { + .name = "ProxyDHCP", + .tx = dhcp_proxy_tx, + .rx = dhcp_proxy_rx, + .expired = dhcp_proxy_expired, + .tx_msgtype = DHCPREQUEST, + .apply_min_timeout = 0, +}; + +/** + * Construct transmitted packet for PXE Boot Server Discovery + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer Destination address + */ +static int dhcp_pxebs_tx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer ) { + struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 }; + int rc; + + /* Set server address */ + peer->sin_addr = *(dhcp->pxe_attempt); + peer->sin_port = ( ( peer->sin_addr.s_addr == INADDR_BROADCAST ) ? + htons ( BOOTPS_PORT ) : htons ( PXE_PORT ) ); + + DBGC ( dhcp, "DHCP %p PXEBS REQUEST to %s:%d for type %d\n", + dhcp, inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ), + le16_to_cpu ( dhcp->pxe_type ) ); + + /* Set boot menu item */ + menu_item.type = dhcp->pxe_type; + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM, + &menu_item, sizeof ( menu_item ) ) ) != 0 ) + return rc; + + return 0; +} + +/** + * Check to see if PXE Boot Server address is acceptable + * + * @v dhcp DHCP session + * @v bs Boot Server address + * @ret accept Boot Server is acceptable + */ +static int dhcp_pxebs_accept ( struct dhcp_session *dhcp, + struct in_addr bs ) { + struct in_addr *accept; + + /* Accept if we have no acceptance filter */ + if ( ! dhcp->pxe_accept ) + return 1; + + /* Scan through acceptance list */ + for ( accept = dhcp->pxe_accept ; accept->s_addr ; accept++ ) { + if ( accept->s_addr == bs.s_addr ) + return 1; + } + + DBGC ( dhcp, "DHCP %p rejecting server %s\n", + dhcp, inet_ntoa ( bs ) ); + return 0; +} + +/** + * Handle received packet during PXE Boot Server Discovery + * + * @v dhcp DHCP session + * @v dhcppkt DHCP packet + * @v peer DHCP server address + * @v msgtype DHCP message type + * @v server_id DHCP server ID + */ +static void dhcp_pxebs_rx ( struct dhcp_session *dhcp, + struct dhcp_packet *dhcppkt, + struct sockaddr_in *peer, uint8_t msgtype, + struct in_addr server_id ) { + struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 }; + int rc; + + DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, + dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), + ntohs ( peer->sin_port ) ); + if ( server_id.s_addr != peer->sin_addr.s_addr ) + DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) ); + + /* Identify boot menu item */ + dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM, + &menu_item, sizeof ( menu_item ) ); + if ( menu_item.type ) + DBGC ( dhcp, " for type %d", ntohs ( menu_item.type ) ); + DBGC ( dhcp, "\n" ); + + /* Filter out unacceptable responses */ + if ( ( peer->sin_port != htons ( BOOTPS_PORT ) ) && + ( peer->sin_port != htons ( PXE_PORT ) ) ) + return; + if ( msgtype != DHCPACK ) + return; + if ( menu_item.type != dhcp->pxe_type ) + return; + if ( ! dhcp_pxebs_accept ( dhcp, ( server_id.s_addr ? + server_id : peer->sin_addr ) ) ) + return; + + /* Register settings */ + dhcppkt->settings.name = PXEBS_SETTINGS_NAME; + if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not register settings: %s\n", + dhcp, strerror ( rc ) ); + dhcp_finished ( dhcp, rc ); + return; + } + + /* Terminate DHCP */ + dhcp_finished ( dhcp, 0 ); +} + +/** + * Handle timer expiry during PXE Boot Server Discovery + * + * @v dhcp DHCP session + */ +static void dhcp_pxebs_expired ( struct dhcp_session *dhcp ) { + unsigned long elapsed = ( currticks() - dhcp->start ); + + /* Give up waiting before we reach the failure point, and fail + * over to the next server in the attempt list + */ + if ( elapsed > PXEBS_MAX_TIMEOUT ) { + dhcp->pxe_attempt++; + if ( dhcp->pxe_attempt->s_addr ) { + dhcp_set_state ( dhcp, &dhcp_state_pxebs ); + return; + } else { + dhcp_finished ( dhcp, -ETIMEDOUT ); + return; + } + } + + /* Retransmit current packet */ + dhcp_tx ( dhcp ); +} + +/** PXE Boot Server Discovery state operations */ +static struct dhcp_session_state dhcp_state_pxebs = { + .name = "PXEBS", + .tx = dhcp_pxebs_tx, + .rx = dhcp_pxebs_rx, + .expired = dhcp_pxebs_expired, + .tx_msgtype = DHCPREQUEST, + .apply_min_timeout = 1, +}; + +/**************************************************************************** + * + * Packet construction + * + */ + +/** + * Construct DHCP client hardware address field and broadcast flag + * + * @v netdev Network device + * @v hlen DHCP hardware address length to fill in + * @v flags DHCP flags to fill in + * @ret chaddr DHCP client hardware address + */ +void * dhcp_chaddr ( struct net_device *netdev, uint8_t *hlen, + uint16_t *flags ) { + struct ll_protocol *ll_protocol = netdev->ll_protocol; + typeof ( ( ( struct dhcphdr * ) NULL )->chaddr ) chaddr; + + /* If the link-layer address cannot fit into the chaddr field + * (as is the case for IPoIB) then try using the hardware + * address instead. If we do this, set the broadcast flag, + * since chaddr then does not represent a valid link-layer + * address for the return path. + * + * If even the hardware address is too large, use an empty + * chaddr field and set the broadcast flag. + * + * This goes against RFC4390, but RFC4390 mandates that we use + * a DHCP client identifier that conforms with RFC4361, which + * we cannot do without either persistent (NIC-independent) + * storage, or by eliminating the hardware address completely + * from the DHCP packet, which seems unfriendly to users. + */ + if ( ( *hlen = ll_protocol->ll_addr_len ) <= sizeof ( chaddr ) ) { + return netdev->ll_addr; + } + *flags = htons ( BOOTP_FL_BROADCAST ); + if ( ( *hlen = ll_protocol->hw_addr_len ) <= sizeof ( chaddr ) ) { + return netdev->hw_addr; + } else { + *hlen = 0; + return NULL; + } +} + +/** + * Create a DHCP packet + * + * @v dhcppkt DHCP packet structure to fill in + * @v netdev Network device + * @v msgtype DHCP message type + * @v options Initial options to include (or NULL) + * @v options_len Length of initial options + * @v data Buffer for DHCP packet + * @v max_len Size of DHCP packet buffer + * @ret rc Return status code + * + * Creates a DHCP packet in the specified buffer, and initialise a + * DHCP packet structure. + */ +int dhcp_create_packet ( struct dhcp_packet *dhcppkt, + struct net_device *netdev, uint8_t msgtype, + const void *options, size_t options_len, + void *data, size_t max_len ) { + struct dhcphdr *dhcphdr = data; + void *chaddr; + int rc; + + /* Sanity check */ + if ( max_len < ( sizeof ( *dhcphdr ) + options_len ) ) + return -ENOSPC; + + /* Initialise DHCP packet content */ + memset ( dhcphdr, 0, max_len ); + dhcphdr->xid = dhcp_xid ( netdev ); + dhcphdr->magic = htonl ( DHCP_MAGIC_COOKIE ); + dhcphdr->htype = ntohs ( netdev->ll_protocol->ll_proto ); + dhcphdr->op = dhcp_op[msgtype]; + chaddr = dhcp_chaddr ( netdev, &dhcphdr->hlen, &dhcphdr->flags ); + memcpy ( dhcphdr->chaddr, chaddr, dhcphdr->hlen ); + memcpy ( dhcphdr->options, options, options_len ); + + /* Initialise DHCP packet structure */ + memset ( dhcppkt, 0, sizeof ( *dhcppkt ) ); + dhcppkt_init ( dhcppkt, data, max_len ); + + /* Set DHCP_MESSAGE_TYPE option */ + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_MESSAGE_TYPE, + &msgtype, sizeof ( msgtype ) ) ) != 0 ) + return rc; + + return 0; +} + +/** + * Create DHCP request packet + * + * @v dhcppkt DHCP packet structure to fill in + * @v netdev Network device + * @v msgtype DHCP message type + * @v ciaddr Client IP address + * @v data Buffer for DHCP packet + * @v max_len Size of DHCP packet buffer + * @ret rc Return status code + * + * Creates a DHCP request packet in the specified buffer, and + * initialise a DHCP packet structure. + */ +int dhcp_create_request ( struct dhcp_packet *dhcppkt, + struct net_device *netdev, unsigned int msgtype, + struct in_addr ciaddr, void *data, size_t max_len ) { + struct dhcp_netdev_desc dhcp_desc; + struct dhcp_client_id client_id; + struct dhcp_client_uuid client_uuid; + uint8_t *dhcp_features; + size_t dhcp_features_len; + size_t ll_addr_len; + ssize_t len; + int rc; + + /* Create DHCP packet */ + if ( ( rc = dhcp_create_packet ( dhcppkt, netdev, msgtype, + dhcp_request_options_data, + sizeof ( dhcp_request_options_data ), + data, max_len ) ) != 0 ) { + DBG ( "DHCP could not create DHCP packet: %s\n", + strerror ( rc ) ); + return rc; + } + + /* Set client IP address */ + dhcppkt->dhcphdr->ciaddr = ciaddr; + + /* Add options to identify the feature list */ + dhcp_features = table_start ( DHCP_FEATURES ); + dhcp_features_len = table_num_entries ( DHCP_FEATURES ); + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_ENCAP, dhcp_features, + dhcp_features_len ) ) != 0 ) { + DBG ( "DHCP could not set features list option: %s\n", + strerror ( rc ) ); + return rc; + } + + /* Add options to identify the network device */ + fetch_setting ( &netdev->settings.settings, &busid_setting, &dhcp_desc, + sizeof ( dhcp_desc ) ); + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_BUS_ID, &dhcp_desc, + sizeof ( dhcp_desc ) ) ) != 0 ) { + DBG ( "DHCP could not set bus ID option: %s\n", + strerror ( rc ) ); + return rc; + } + + /* Add DHCP client identifier. Required for Infiniband, and + * doesn't hurt other link layers. + */ + client_id.ll_proto = ntohs ( netdev->ll_protocol->ll_proto ); + ll_addr_len = netdev->ll_protocol->ll_addr_len; + assert ( ll_addr_len <= sizeof ( client_id.ll_addr ) ); + memcpy ( client_id.ll_addr, netdev->ll_addr, ll_addr_len ); + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_ID, &client_id, + ( ll_addr_len + 1 ) ) ) != 0 ) { + DBG ( "DHCP could not set client ID: %s\n", + strerror ( rc ) ); + return rc; + } + + /* Add client UUID, if we have one. Required for PXE. */ + client_uuid.type = DHCP_CLIENT_UUID_TYPE; + if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting, + &client_uuid.uuid ) ) >= 0 ) { + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_UUID, + &client_uuid, + sizeof ( client_uuid ) ) ) != 0 ) { + DBG ( "DHCP could not set client UUID: %s\n", + strerror ( rc ) ); + return rc; + } + } + + /* Add user class, if we have one. */ + if ( ( len = fetch_setting_len ( NULL, &user_class_setting ) ) >= 0 ) { + char user_class[len]; + fetch_setting ( NULL, &user_class_setting, user_class, + sizeof ( user_class ) ); + if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_USER_CLASS_ID, + &user_class, + sizeof ( user_class ) ) ) != 0 ) { + DBG ( "DHCP could not set user class: %s\n", + strerror ( rc ) ); + return rc; + } + } + + return 0; +} + +/**************************************************************************** + * + * Data transfer interface + * + */ + +/** + * Transmit DHCP request + * + * @v dhcp DHCP session + * @ret rc Return status code + */ +static int dhcp_tx ( struct dhcp_session *dhcp ) { + static struct sockaddr_in peer = { + .sin_family = AF_INET, + }; + struct xfer_metadata meta = { + .netdev = dhcp->netdev, + .src = ( struct sockaddr * ) &dhcp->local, + .dest = ( struct sockaddr * ) &peer, + }; + struct io_buffer *iobuf; + uint8_t msgtype = dhcp->state->tx_msgtype; + struct dhcp_packet dhcppkt; + int rc; + + /* Start retry timer. Do this first so that failures to + * transmit will be retried. + */ + start_timer ( &dhcp->timer ); + + /* Allocate buffer for packet */ + iobuf = xfer_alloc_iob ( &dhcp->xfer, DHCP_MIN_LEN ); + if ( ! iobuf ) + return -ENOMEM; + + /* Create basic DHCP packet in temporary buffer */ + if ( ( rc = dhcp_create_request ( &dhcppkt, dhcp->netdev, msgtype, + dhcp->local.sin_addr, iobuf->data, + iob_tailroom ( iobuf ) ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not construct DHCP request: %s\n", + dhcp, strerror ( rc ) ); + goto done; + } + + /* Fill in packet based on current state */ + if ( ( rc = dhcp->state->tx ( dhcp, &dhcppkt, &peer ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not fill DHCP request: %s\n", + dhcp, strerror ( rc ) ); + goto done; + } + + /* Transmit the packet */ + iob_put ( iobuf, dhcppkt.len ); + if ( ( rc = xfer_deliver_iob_meta ( &dhcp->xfer, iob_disown ( iobuf ), + &meta ) ) != 0 ) { + DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n", + dhcp, strerror ( rc ) ); + goto done; + } + + done: + free_iob ( iobuf ); + return rc; +} + +/** + * Receive new data + * + * @v xfer Data transfer interface + * @v iobuf I/O buffer + * @v meta Transfer metadata + * @ret rc Return status code + */ +static int dhcp_deliver_iob ( struct xfer_interface *xfer, + struct io_buffer *iobuf, + struct xfer_metadata *meta ) { + struct dhcp_session *dhcp = + container_of ( xfer, struct dhcp_session, xfer ); + struct sockaddr_in *peer; + size_t data_len; + struct dhcp_packet *dhcppkt; + struct dhcphdr *dhcphdr; + uint8_t msgtype = 0; + struct in_addr server_id = { 0 }; + int rc = 0; + + /* Sanity checks */ + if ( ! meta->src ) { + DBGC ( dhcp, "DHCP %p received packet without source port\n", + dhcp ); + rc = -EINVAL; + goto err_no_src; + } + peer = ( struct sockaddr_in * ) meta->src; + + /* Create a DHCP packet containing the I/O buffer contents. + * Whilst we could just use the original buffer in situ, that + * would waste the unused space in the packet buffer, and also + * waste a relatively scarce fully-aligned I/O buffer. + */ + data_len = iob_len ( iobuf ); + dhcppkt = zalloc ( sizeof ( *dhcppkt ) + data_len ); + if ( ! dhcppkt ) { + rc = -ENOMEM; + goto err_alloc_dhcppkt; + } + dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) ); + memcpy ( dhcphdr, iobuf->data, data_len ); + dhcppkt_init ( dhcppkt, dhcphdr, data_len ); + + /* Identify message type */ + dhcppkt_fetch ( dhcppkt, DHCP_MESSAGE_TYPE, &msgtype, + sizeof ( msgtype ) ); + + /* Identify server ID */ + dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER, + &server_id, sizeof ( server_id ) ); + + /* Check for matching transaction ID */ + if ( dhcphdr->xid != dhcp_xid ( dhcp->netdev ) ) { + DBGC ( dhcp, "DHCP %p %s from %s:%d has bad transaction " + "ID\n", dhcp, dhcp_msgtype_name ( msgtype ), + inet_ntoa ( peer->sin_addr ), + ntohs ( peer->sin_port ) ); + rc = -EINVAL; + goto err_xid; + }; + + /* Handle packet based on current state */ + dhcp->state->rx ( dhcp, dhcppkt, peer, msgtype, server_id ); + + err_xid: + dhcppkt_put ( dhcppkt ); + err_alloc_dhcppkt: + err_no_src: + free_iob ( iobuf ); + return rc; +} + +/** DHCP data transfer interface operations */ +static struct xfer_interface_operations dhcp_xfer_operations = { + .close = ignore_xfer_close, + .vredirect = xfer_vreopen, + .window = unlimited_xfer_window, + .alloc_iob = default_xfer_alloc_iob, + .deliver_iob = dhcp_deliver_iob, + .deliver_raw = xfer_deliver_as_iob, +}; + +/** + * Handle DHCP retry timer expiry + * + * @v timer DHCP retry timer + * @v fail Failure indicator + */ +static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) { + struct dhcp_session *dhcp = + container_of ( timer, struct dhcp_session, timer ); + + /* If we have failed, terminate DHCP */ + if ( fail ) { + dhcp_finished ( dhcp, -ETIMEDOUT ); + return; + } + + /* Handle timer expiry based on current state */ + dhcp->state->expired ( dhcp ); +} + +/**************************************************************************** + * + * Job control interface + * + */ + +/** + * Handle kill() event received via job control interface + * + * @v job DHCP job control interface + */ +static void dhcp_job_kill ( struct job_interface *job ) { + struct dhcp_session *dhcp = + container_of ( job, struct dhcp_session, job ); + + /* Terminate DHCP session */ + dhcp_finished ( dhcp, -ECANCELED ); +} + +/** DHCP job control interface operations */ +static struct job_interface_operations dhcp_job_operations = { + .done = ignore_job_done, + .kill = dhcp_job_kill, + .progress = ignore_job_progress, +}; + +/**************************************************************************** + * + * Instantiators + * + */ + +/** + * DHCP peer address for socket opening + * + * This is a dummy address; the only useful portion is the socket + * family (so that we get a UDP connection). The DHCP client will set + * the IP address and source port explicitly on each transmission. + */ +static struct sockaddr dhcp_peer = { + .sa_family = AF_INET, +}; + +/** + * Start DHCP state machine on a network device + * + * @v job Job control interface + * @v netdev Network device + * @ret rc Return status code, or positive if cached + * + * Starts DHCP on the specified network device. If successful, the + * DHCPACK (and ProxyDHCPACK, if applicable) will be registered as + * option sources. + * + * On a return of 0, a background job has been started to perform the + * DHCP request. Any nonzero return means the job has not been + * started; a positive return value indicates the success condition of + * having fetched the appropriate data from cached information. + */ +int start_dhcp ( struct job_interface *job, struct net_device *netdev ) { + struct dhcp_session *dhcp; + int rc; + + /* Check for cached DHCP information */ + get_cached_dhcpack(); + if ( fetch_uintz_setting ( NULL, &use_cached_setting ) ) { + DBG ( "DHCP using cached network settings\n" ); + return 1; + } + + /* Allocate and initialise structure */ + dhcp = zalloc ( sizeof ( *dhcp ) ); + if ( ! dhcp ) + return -ENOMEM; + dhcp->refcnt.free = dhcp_free; + job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt ); + xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt ); + dhcp->netdev = netdev_get ( netdev ); + dhcp->local.sin_family = AF_INET; + dhcp->local.sin_port = htons ( BOOTPC_PORT ); + dhcp->timer.expired = dhcp_timer_expired; + + /* Instantiate child objects and attach to our interfaces */ + if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer, + ( struct sockaddr * ) &dhcp->local ) ) != 0 ) + goto err; + + /* Enter DHCPDISCOVER state */ + dhcp_set_state ( dhcp, &dhcp_state_discover ); + + /* Attach parent interface, mortalise self, and return */ + job_plug_plug ( &dhcp->job, job ); + ref_put ( &dhcp->refcnt ); + return 0; + + err: + dhcp_finished ( dhcp, rc ); + ref_put ( &dhcp->refcnt ); + return rc; +} + +/** + * Retrieve list of PXE boot servers for a given server type + * + * @v dhcp DHCP session + * @v raw DHCP PXE boot server list + * @v raw_len Length of DHCP PXE boot server list + * @v ip IP address list to fill in + * + * The caller must ensure that the IP address list has sufficient + * space. + */ +static void pxebs_list ( struct dhcp_session *dhcp, void *raw, + size_t raw_len, struct in_addr *ip ) { + struct dhcp_pxe_boot_server *server = raw; + size_t server_len; + unsigned int i; + + while ( raw_len ) { + if ( raw_len < sizeof ( *server ) ) { + DBGC ( dhcp, "DHCP %p malformed PXE server list\n", + dhcp ); + break; + } + server_len = offsetof ( typeof ( *server ), + ip[ server->num_ip ] ); + if ( raw_len < server_len ) { + DBGC ( dhcp, "DHCP %p malformed PXE server list\n", + dhcp ); + break; + } + if ( server->type == dhcp->pxe_type ) { + for ( i = 0 ; i < server->num_ip ; i++ ) + *(ip++) = server->ip[i]; + } + server = ( ( ( void * ) server ) + server_len ); + raw_len -= server_len; + } +} + +/** + * Start PXE Boot Server Discovery on a network device + * + * @v job Job control interface + * @v netdev Network device + * @v pxe_type PXE server type + * @ret rc Return status code + * + * Starts PXE Boot Server Discovery on the specified network device. + * If successful, the Boot Server ACK will be registered as an option + * source. + */ +int start_pxebs ( struct job_interface *job, struct net_device *netdev, + unsigned int pxe_type ) { + struct setting pxe_discovery_control_setting = + { .tag = DHCP_PXE_DISCOVERY_CONTROL }; + struct setting pxe_boot_servers_setting = + { .tag = DHCP_PXE_BOOT_SERVERS }; + struct setting pxe_boot_server_mcast_setting = + { .tag = DHCP_PXE_BOOT_SERVER_MCAST }; + ssize_t pxebs_list_len; + struct dhcp_session *dhcp; + struct in_addr *ip; + unsigned int pxe_discovery_control; + int rc; + + /* Get upper bound for PXE boot server IP address list */ + pxebs_list_len = fetch_setting_len ( NULL, &pxe_boot_servers_setting ); + if ( pxebs_list_len < 0 ) + pxebs_list_len = 0; + + /* Allocate and initialise structure */ + dhcp = zalloc ( sizeof ( *dhcp ) + sizeof ( *ip ) /* mcast */ + + sizeof ( *ip ) /* bcast */ + pxebs_list_len + + sizeof ( *ip ) /* terminator */ ); + if ( ! dhcp ) + return -ENOMEM; + dhcp->refcnt.free = dhcp_free; + job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt ); + xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt ); + dhcp->netdev = netdev_get ( netdev ); + dhcp->local.sin_family = AF_INET; + fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting, + &dhcp->local.sin_addr ); + dhcp->local.sin_port = htons ( BOOTPC_PORT ); + dhcp->pxe_type = cpu_to_le16 ( pxe_type ); + dhcp->timer.expired = dhcp_timer_expired; + + /* Construct PXE boot server IP address lists */ + pxe_discovery_control = + fetch_uintz_setting ( NULL, &pxe_discovery_control_setting ); + ip = ( ( ( void * ) dhcp ) + sizeof ( *dhcp ) ); + dhcp->pxe_attempt = ip; + if ( ! ( pxe_discovery_control & PXEBS_NO_MULTICAST ) ) { + fetch_ipv4_setting ( NULL, &pxe_boot_server_mcast_setting, ip); + if ( ip->s_addr ) + ip++; + } + if ( ! ( pxe_discovery_control & PXEBS_NO_BROADCAST ) ) + (ip++)->s_addr = INADDR_BROADCAST; + if ( pxe_discovery_control & PXEBS_NO_UNKNOWN_SERVERS ) + dhcp->pxe_accept = ip; + if ( pxebs_list_len ) { + uint8_t buf[pxebs_list_len]; + + fetch_setting ( NULL, &pxe_boot_servers_setting, + buf, sizeof ( buf ) ); + pxebs_list ( dhcp, buf, sizeof ( buf ), ip ); + } + if ( ! dhcp->pxe_attempt->s_addr ) { + DBGC ( dhcp, "DHCP %p has no PXE boot servers for type %04x\n", + dhcp, pxe_type ); + rc = -EINVAL; + goto err; + } + + /* Dump out PXE server lists */ + DBGC ( dhcp, "DHCP %p attempting", dhcp ); + for ( ip = dhcp->pxe_attempt ; ip->s_addr ; ip++ ) + DBGC ( dhcp, " %s", inet_ntoa ( *ip ) ); + DBGC ( dhcp, "\n" ); + if ( dhcp->pxe_accept ) { + DBGC ( dhcp, "DHCP %p accepting", dhcp ); + for ( ip = dhcp->pxe_accept ; ip->s_addr ; ip++ ) + DBGC ( dhcp, " %s", inet_ntoa ( *ip ) ); + DBGC ( dhcp, "\n" ); + } + + /* Instantiate child objects and attach to our interfaces */ + if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer, + ( struct sockaddr * ) &dhcp->local ) ) != 0 ) + goto err; + + /* Enter PXEBS state */ + dhcp_set_state ( dhcp, &dhcp_state_pxebs ); + + /* Attach parent interface, mortalise self, and return */ + job_plug_plug ( &dhcp->job, job ); + ref_put ( &dhcp->refcnt ); + return 0; + + err: + dhcp_finished ( dhcp, rc ); + ref_put ( &dhcp->refcnt ); + return rc; +} |