/* * Copyright (C) 2006 Michael Brown . * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** @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_MAX_MESSAGE_SIZE, DHCP_WORD ( ETH_MAX_MTU - 20 /* IP header */ - 8 /* UDP header */ ), DHCP_CLIENT_ARCHITECTURE, DHCP_WORD ( 0 ), DHCP_CLIENT_NDI, DHCP_OPTION ( 1 /* UNDI */ , 2, 1 /* v2.1 */ ), DHCP_VENDOR_CLASS_ID, DHCP_STRING ( 'P', 'X', 'E', 'C', 'l', 'i', 'e', 'n', 't', ':', 'A', 'r', 'c', 'h', ':', '0', '0', '0', '0', '0', ':', 'U', 'N', 'D', 'I', ':', '0', '0', '2', '0', '0', '1' ), DHCP_PARAMETER_REQUEST_LIST, DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_DNS_SERVERS, DHCP_LOG_SERVERS, DHCP_HOST_NAME, DHCP_DOMAIN_NAME, DHCP_ROOT_PATH, DHCP_VENDOR_ENCAP, DHCP_VENDOR_CLASS_ID, DHCP_TFTP_SERVER_NAME, DHCP_BOOTFILE_NAME, DHCP_EB_ENCAP, DHCP_ISCSI_INITIATOR_IQN ), DHCP_END }; /** DHCP feature codes */ static uint8_t dhcp_features[0] __table_start ( uint8_t, dhcp_features ); static uint8_t dhcp_features_end[0] __table_end ( uint8_t, dhcp_features ); /** Version number feature */ FEATURE_VERSION ( VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH ); /** DHCP 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, }; /** * 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"; } } /** * 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 */ void ( * rx ) ( struct dhcp_session *dhcp, struct dhcp_packet *dhcppkt, struct sockaddr_in *peer, uint8_t msgtype ); /** 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; /** 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; /** Offered IP address */ struct in_addr offer; /** DHCP server */ struct in_addr server; /** DHCP offer priority */ int priority; /** ProxyDHCP protocol extensions should be ignored */ int no_pxedhcp; /** ProxyDHCP server */ struct in_addr proxy_server; /** ProxyDHCP server priority */ int proxy_priority; /** PXE Boot Server */ struct in_addr pxe_server; /** PXE Boot Server type */ uint16_t pxe_type; /** Retransmission timer */ struct retry_timer timer; /** Start time of the current state (in ticks) */ unsigned long start; }; /** * Free DHCP session * * @v refcnt Reference counter */ static void dhcp_free ( struct refcnt *refcnt ) { struct dhcp_session *dhcp = container_of ( refcnt, struct dhcp_session, refcnt ); netdev_put ( dhcp->netdev ); 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 ); } /**************************************************************************** * * DHCP state machine * */ /** * Construct transmitted packet for DHCP discovery * * @v dhcp DHCP session * @v dhcppkt DHCP packet * @v peer Destination address */ static int dhcp_discovery_tx ( struct dhcp_session *dhcp, struct dhcp_packet *dhcppkt __unused, struct sockaddr_in *peer ) { DBGC ( dhcp, "DHCP %p DHCPDISCOVER\n", dhcp ); /* Set server address */ peer->sin_addr.s_addr = INADDR_BROADCAST; peer->sin_port = htons ( BOOTPS_PORT ); return 0; } /** * Handle received packet during DHCP discovery * * @v dhcp DHCP session * @v dhcppkt DHCP packet * @v peer DHCP server address * @v msgtype DHCP message type */ 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 = { 0 }; struct in_addr ip; char vci[9]; /* "PXEClient" */ int vci_len; int has_pxeclient; int8_t priority = 0; uint8_t no_pxedhcp = 0; unsigned long elapsed; DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ) ); /* Identify server ID */ dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER, &server_id, sizeof ( server_id ) ); if ( server_id.s_addr != peer->sin_addr.s_addr ) DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) ); /* Identify offered IP address */ ip = dhcppkt->dhcphdr->yiaddr; if ( ip.s_addr ) DBGC ( dhcp, " for %s", inet_ntoa ( ip ) ); /* Identify "PXEClient" vendor class */ vci_len = dhcppkt_fetch ( dhcppkt, DHCP_VENDOR_CLASS_ID, vci, sizeof ( vci ) ); has_pxeclient = ( ( vci_len >= ( int ) sizeof ( vci ) ) && ( strncmp ( "PXEClient", vci, sizeof (vci) ) == 0 )); if ( has_pxeclient ) DBGC ( dhcp, " pxe" ); /* Identify priority */ dhcppkt_fetch ( dhcppkt, DHCP_EB_PRIORITY, &priority, sizeof ( priority ) ); if ( priority ) DBGC ( dhcp, " pri %d", priority ); /* Identify ignore-PXE flag */ dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &no_pxedhcp, sizeof ( no_pxedhcp ) ); if ( no_pxedhcp ) DBGC ( dhcp, " nopxe" ); DBGC ( dhcp, "\n" ); /* Select as DHCP offer, if applicable */ if ( ip.s_addr && ( peer->sin_port == htons ( BOOTPS_PORT ) ) && ( ( msgtype == DHCPOFFER ) || ( ! msgtype /* BOOTP */ ) ) && ( priority >= dhcp->priority ) ) { dhcp->offer = ip; dhcp->server = server_id; dhcp->priority = priority; dhcp->no_pxedhcp = no_pxedhcp; } /* Select as ProxyDHCP offer, if applicable */ if ( has_pxeclient && ( msgtype == DHCPOFFER ) && ( priority >= dhcp->proxy_priority ) ) { dhcp->proxy_server = server_id; dhcp->proxy_priority = priority; } /* We can exit the discovery state when we have a valid * DHCPOFFER, and either: * * o The DHCPOFFER instructs us to ignore ProxyDHCPOFFERs, or * o We have a valid ProxyDHCPOFFER, or * o We have allowed sufficient time for ProxyDHCPOFFERs. */ /* If we don't yet have a DHCPOFFER, do nothing */ if ( ! dhcp->offer.s_addr ) return; /* If we can't yet transition to DHCPREQUEST, do nothing */ elapsed = ( currticks() - dhcp->start ); if ( ! ( dhcp->no_pxedhcp || dhcp->proxy_server.s_addr || ( 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->offer.s_addr && ( 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; DBGC ( dhcp, "DHCP %p DHCPREQUEST to %s:%d", dhcp, inet_ntoa ( dhcp->server ), BOOTPS_PORT ); DBGC ( dhcp, " for %s\n", inet_ntoa ( dhcp->offer ) ); /* Set server ID */ if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER, &dhcp->server, sizeof ( dhcp->server ) ) ) != 0 ) return rc; /* Set requested IP address */ if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS, &dhcp->offer, sizeof ( dhcp->offer ) ) ) != 0 ) return rc; /* Set server address */ peer->sin_addr.s_addr = INADDR_BROADCAST; peer->sin_port = htons ( BOOTPS_PORT ); return 0; } /** * Handle received packet during DHCP request * * @v dhcp DHCP session * @v dhcppkt DHCP packet * @v peer DHCP server address * @v msgtype DHCP message type */ 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 = { 0 }; struct in_addr ip; struct settings *parent; int rc; DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ) ); /* Identify server ID */ dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER, &server_id, sizeof ( server_id ) ); 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->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; } /* Start ProxyDHCPREQUEST if applicable */ if ( dhcp->proxy_server.s_addr && ( ! dhcp->no_pxedhcp ) ) { dhcp_set_state ( dhcp, &dhcp_state_proxy ); return; } /* Terminate DHCP */ dhcp_finished ( dhcp, 0 ); } /** * Handle timer expiry during DHCP discovery * * @v dhcp DHCP session */ static void dhcp_request_expired ( struct dhcp_session *dhcp ) { /* Retransmit current packet */ dhcp_tx ( dhcp ); } /** DHCP request state operations */ static struct dhcp_session_state dhcp_state_request = { .name = "request", .tx = dhcp_request_tx, .rx = dhcp_request_rx, .expired = dhcp_request_expired, .tx_msgtype = DHCPREQUEST, .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; DBGC ( dhcp, "DHCP %p ProxyDHCP REQUEST to %s:%d\n", dhcp, inet_ntoa ( dhcp->proxy_server ), PXE_PORT ); /* Set server ID */ if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER, &dhcp->proxy_server, sizeof ( dhcp->proxy_server ) ) ) != 0 ) return rc; /* Set server address */ peer->sin_addr = dhcp->proxy_server; peer->sin_port = htons ( PXE_PORT ); return 0; } /** * Handle received packet during ProxyDHCP request * * @v dhcp DHCP session * @v dhcppkt DHCP packet * @v peer DHCP server address * @v msgtype DHCP message type */ 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 = { 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 ) ); /* Identify server ID */ dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER, &server_id, sizeof ( server_id ) ); 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 ) return; if ( server_id.s_addr /* Linux PXE server omits server ID */ && ( server_id.s_addr != dhcp->proxy_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 ) { 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; DBGC ( dhcp, "DHCP %p PXEBS REQUEST to %s:%d for type %d\n", dhcp, inet_ntoa ( dhcp->pxe_server ), PXE_PORT, ntohs ( 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; /* Set server address */ peer->sin_addr = dhcp->pxe_server; peer->sin_port = htons ( PXE_PORT ); 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 */ static void dhcp_pxebs_rx ( struct dhcp_session *dhcp, struct dhcp_packet *dhcppkt, struct sockaddr_in *peer, uint8_t msgtype ) { 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 ) ); /* 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 ( PXE_PORT ) ) return; if ( msgtype != DHCPACK ) return; if ( menu_item.type != dhcp->pxe_type ) 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 ) { /* 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 * */ /** * 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; unsigned int hlen; 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]; /* If hardware length exceeds the chaddr field length, don't * use the chaddr field. This is as per RFC4390. */ hlen = netdev->ll_protocol->ll_addr_len; if ( hlen > sizeof ( dhcphdr->chaddr ) ) { hlen = 0; dhcphdr->flags = htons ( BOOTP_FL_BROADCAST ); } dhcphdr->hlen = hlen; memcpy ( dhcphdr->chaddr, netdev->ll_addr, hlen ); memcpy ( dhcphdr->options, options, 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 device_description *desc = &netdev->dev->desc; struct dhcp_netdev_desc dhcp_desc; struct dhcp_client_id client_id; struct dhcp_client_uuid client_uuid; size_t dhcp_features_len; size_t ll_addr_len; 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_len = ( dhcp_features_end - dhcp_features ); if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_ENCAP, dhcp_features, dhcp_features_len ) ) != 0 ) { DBG ( "DHCP could not set features list option: %s\n", strerror ( rc ) ); return rc; } /* Add options to identify the network device */ dhcp_desc.type = desc->bus_type; dhcp_desc.vendor = htons ( desc->vendor ); dhcp_desc.device = htons ( desc->device ); if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_BUS_ID, &dhcp_desc, sizeof ( dhcp_desc ) ) ) != 0 ) { DBG ( "DHCP could not set bus ID option: %s\n", strerror ( rc ) ); return rc; } /* Add DHCP client identifier. Required for Infiniband, and * doesn't hurt other link layers. */ client_id.ll_proto = ntohs ( netdev->ll_protocol->ll_proto ); ll_addr_len = netdev->ll_protocol->ll_addr_len; assert ( ll_addr_len <= sizeof ( client_id.ll_addr ) ); memcpy ( client_id.ll_addr, netdev->ll_addr, ll_addr_len ); if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_ID, &client_id, ( ll_addr_len + 1 ) ) ) != 0 ) { DBG ( "DHCP could not set client ID: %s\n", strerror ( rc ) ); return rc; } /* Add client UUID, if we have one. Required for PXE. */ client_uuid.type = DHCP_CLIENT_UUID_TYPE; if ( ( 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 ); rc = xfer_deliver_iob_meta ( &dhcp->xfer, iobuf, &meta ); iobuf = NULL; if ( rc != 0 ) { DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n", dhcp, strerror ( rc ) ); goto done; } done: free_iob ( iobuf ); return rc; } /** * 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; int rc = 0; /* Sanity checks */ if ( ! meta ) { DBGC ( dhcp, "DHCP %p received packet without metadata\n", dhcp ); rc = -EINVAL; goto err_no_meta; } if ( ! meta->src ) { DBGC ( dhcp, "DHCP %p received packet without source port\n", dhcp ); rc = -EINVAL; goto err_no_src; } 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 ) ); /* 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 ); err_xid: dhcppkt_put ( dhcppkt ); err_alloc_dhcppkt: err_no_src: err_no_meta: free_iob ( iobuf ); return rc; } /** DHCP data transfer interface operations */ static struct xfer_interface_operations dhcp_xfer_operations = { .close = ignore_xfer_close, .vredirect = xfer_vopen, .window = unlimited_xfer_window, .alloc_iob = default_xfer_alloc_iob, .deliver_iob = dhcp_deliver_iob, .deliver_raw = xfer_deliver_as_iob, }; /** * Handle DHCP retry timer expiry * * @v timer DHCP retry timer * @v fail Failure indicator */ static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) { struct dhcp_session *dhcp = container_of ( timer, struct dhcp_session, timer ); /* 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 * * Starts DHCP on the specified network device. If successful, the * DHCPACK (and ProxyDHCPACK, if applicable) will be registered as * option sources. */ int start_dhcp ( struct job_interface *job, struct net_device *netdev ) { struct dhcp_session *dhcp; int rc; /* Allocate and initialise structure */ dhcp = zalloc ( sizeof ( *dhcp ) ); if ( ! dhcp ) return -ENOMEM; dhcp->refcnt.free = dhcp_free; job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt ); xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt ); dhcp->netdev = netdev_get ( netdev ); dhcp->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; } /** * Start PXE Boot Server Discovery on a network device * * @v job Job control interface * @v netdev Network device * @v pxe_server PXE server (may be a multicast address) * @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, struct in_addr pxe_server, unsigned int pxe_type ) { struct dhcp_session *dhcp; int rc; /* Allocate and initialise structure */ dhcp = zalloc ( sizeof ( *dhcp ) ); if ( ! dhcp ) return -ENOMEM; dhcp->refcnt.free = dhcp_free; job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt ); xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt ); dhcp->netdev = netdev_get ( netdev ); dhcp->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_server = pxe_server; dhcp->pxe_type = htons ( pxe_type ); 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 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; }