diff options
| -rw-r--r-- | src/net/udp/dhcp.c | 314 |
1 files changed, 228 insertions, 86 deletions
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c index 0edd0ad8..ce2c8207 100644 --- a/src/net/udp/dhcp.c +++ b/src/net/udp/dhcp.c @@ -206,6 +206,36 @@ 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 */ @@ -222,22 +252,6 @@ struct dhcp_session { /** 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 port */ - uint16_t proxy_port; - /** ProxyDHCP server priority */ - int proxy_priority; - /** PXE Boot Server type */ uint16_t pxe_type; /** List of PXE Boot Servers to attempt */ @@ -249,6 +263,11 @@ struct dhcp_session { 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]; }; /** @@ -259,6 +278,12 @@ struct dhcp_session { 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 ); @@ -303,6 +328,35 @@ static void dhcp_set_state ( struct dhcp_session *dhcp, 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 @@ -330,7 +384,7 @@ static int dhcp_discovery_tx ( struct dhcp_session *dhcp, } /** - * Handle received packet during DHCP discovery + * Handle received DHCPOFFER during any state * * @v dhcp DHCP session * @v dhcppkt DHCP packet @@ -338,19 +392,17 @@ static int dhcp_discovery_tx ( struct dhcp_session *dhcp, * @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 ) { - struct in_addr ip; +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; - int8_t priority = 0; - uint8_t no_pxedhcp = 0; - unsigned long elapsed; + struct dhcp_offer *offer; + int i; DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp, dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ), @@ -359,9 +411,27 @@ static void dhcp_discovery_rx ( struct dhcp_session *dhcp, 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 ) ); + 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, @@ -375,43 +445,53 @@ static void dhcp_discovery_rx ( struct dhcp_session *dhcp, 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, &priority, - sizeof ( priority ) ); - if ( priority ) - DBGC ( dhcp, " pri %d", 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, &no_pxedhcp, - sizeof ( no_pxedhcp ) ); - if ( no_pxedhcp ) + dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &offer->no_pxedhcp, + sizeof ( offer->no_pxedhcp ) ); + if ( offer->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; - } + /* 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; - /* Select as ProxyDHCP offer, if applicable */ - if ( has_pxeclient && ( msgtype == DHCPOFFER ) && - ( priority >= dhcp->proxy_priority ) ) { - /* If the offer already includes the PXE options, then - * assume that we can send the ProxyDHCPREQUEST to - * port 67 (since the DHCPDISCOVER that triggered this - * ProxyDHCPOFFER was sent to port 67). Otherwise, - * send the ProxyDHCPREQUEST to port 4011. - */ - dhcp->proxy_server = server_id; - dhcp->proxy_port = ( has_pxeopts ? htons ( BOOTPS_PORT ) - : htons ( PXE_PORT ) ); - dhcp->proxy_priority = priority; - } + 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: @@ -422,12 +502,14 @@ static void dhcp_discovery_rx ( struct dhcp_session *dhcp, */ /* If we don't yet have a DHCPOFFER, do nothing */ - if ( ! dhcp->offer.s_addr ) + 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 ( ! ( dhcp->no_pxedhcp || dhcp->proxy_server.s_addr || + if ( ! ( ip_offer->no_pxedhcp || + dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) || ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) ) return; @@ -444,7 +526,8 @@ 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 ) ) { + if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) && + ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) { dhcp_set_state ( dhcp, &dhcp_state_request ); return; } @@ -474,21 +557,23 @@ 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 ( dhcp->server ), BOOTPS_PORT ); - DBGC ( dhcp, " for %s\n", inet_ntoa ( dhcp->offer ) ); + 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, - &dhcp->server, - sizeof ( dhcp->server ) ) ) != 0 ) + &offer->server, + sizeof ( offer->server ) ) ) != 0 ) return rc; /* Set requested IP address */ if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS, - &dhcp->offer, - sizeof ( dhcp->offer ) ) ) != 0 ) + &offer->ip, sizeof ( offer->ip ) ) ) != 0 ) return rc; /* Set server address */ @@ -514,6 +599,18 @@ static void dhcp_request_rx ( struct dhcp_session *dhcp, 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 ), @@ -532,7 +629,7 @@ static void dhcp_request_rx ( struct dhcp_session *dhcp, return; if ( msgtype /* BOOTP */ && ( msgtype != DHCPACK ) ) return; - if ( server_id.s_addr != dhcp->server.s_addr ) + if ( server_id.s_addr != dhcp->current_offer->server.s_addr ) return; /* Record assigned address */ @@ -547,18 +644,31 @@ static void dhcp_request_rx ( struct dhcp_session *dhcp, return; } - /* Start ProxyDHCPREQUEST if applicable */ - if ( dhcp->proxy_server.s_addr /* Have ProxyDHCP server */ && - ( ! dhcp->no_pxedhcp ) /* ProxyDHCP not disabled */ && - ( /* ProxyDHCP server is not just the DHCP server itself */ - ( dhcp->proxy_server.s_addr != dhcp->server.s_addr ) || - ( dhcp->proxy_port != htons ( BOOTPS_PORT ) ) ) ) { + /* 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 ); - return; } - - /* Terminate DHCP */ - dhcp_finished ( dhcp, 0 ); } /** @@ -593,19 +703,22 @@ 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 ( dhcp->proxy_server ), ntohs ( dhcp->proxy_port ) ); + inet_ntoa ( offer->server ), PXE_PORT ); /* Set server ID */ if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER, - &dhcp->proxy_server, - sizeof ( dhcp->proxy_server ) ) ) != 0 ) + &offer->server, + sizeof ( offer->server ) ) ) != 0 ) return rc; /* Set server address */ - peer->sin_addr = dhcp->proxy_server; - peer->sin_port = dhcp->proxy_port; + peer->sin_addr = offer->server; + peer->sin_port = htons ( PXE_PORT ); return 0; } @@ -625,6 +738,13 @@ static void dhcp_proxy_rx ( struct dhcp_session *dhcp, 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 ) ); @@ -633,12 +753,12 @@ static void dhcp_proxy_rx ( struct dhcp_session *dhcp, DBGC ( dhcp, "\n" ); /* Filter out unacceptable responses */ - if ( peer->sin_port != dhcp->proxy_port ) + if ( peer->sin_port != htons ( PXE_PORT ) ) return; - if ( ( msgtype != DHCPOFFER ) && ( msgtype != DHCPACK ) ) + if ( msgtype != DHCPACK && msgtype != DHCPOFFER ) return; if ( server_id.s_addr /* Linux PXE server omits server ID */ && - ( server_id.s_addr != dhcp->proxy_server.s_addr ) ) + ( server_id.s_addr != dhcp->current_offer->server.s_addr ) ) return; /* Register settings */ @@ -664,6 +784,28 @@ static void dhcp_proxy_expired ( struct dhcp_session *dhcp ) { /* 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; } |