pxe_udp.c File Reference

PXE UDP API. More...

#include <string.h>
#include <byteswap.h>
#include <ipxe/iobuf.h>
#include <ipxe/xfer.h>
#include <ipxe/udp.h>
#include <ipxe/uaccess.h>
#include <ipxe/process.h>
#include <ipxe/netdevice.h>
#include <ipxe/malloc.h>
#include <realmode.h>
#include <pxe.h>

Go to the source code of this file.

Data Structures
struct	pxe_udp_pseudo_header
	A PXE UDP pseudo-header. More...
struct	pxe_udp_connection
	A PXE UDP connection. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static int	pxe_udp_deliver (struct pxe_udp_connection *pxe_udp, struct io_buffer *iobuf, struct xfer_metadata *meta)
	Receive PXE UDP data. More...
static PXENV_EXIT_t	pxenv_udp_open (struct s_PXENV_UDP_OPEN *pxenv_udp_open)
	UDP OPEN. More...
static PXENV_EXIT_t	pxenv_udp_close (struct s_PXENV_UDP_CLOSE *pxenv_udp_close)
	UDP CLOSE. More...
static PXENV_EXIT_t	pxenv_udp_write (struct s_PXENV_UDP_WRITE *pxenv_udp_write)
	UDP WRITE. More...
static PXENV_EXIT_t	pxenv_udp_read (struct s_PXENV_UDP_READ *pxenv_udp_read)
	UDP READ. More...
static unsigned int	pxe_udp_discard (void)
	Discard some cached PXE UDP data. More...
struct cache_discarder pxe_udp_discarder	__cache_discarder (CACHE_NORMAL)
	PXE UDP cache discarder. More...

Variables
static struct interface_operation	pxe_udp_xfer_operations []
	PXE UDP data transfer interface operations. More...
static struct interface_descriptor	pxe_udp_xfer_desc
	PXE UDP data transfer interface descriptor. More...
static struct pxe_udp_connection	pxe_udp
	The PXE UDP connection. More...
struct pxe_api_call pxe_udp_api []	__pxe_api_call
	PXE UDP API. More...

Detailed Description

PXE UDP API.

Definition in file pxe_udp.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

pxe_udp_deliver()

static int pxe_udp_deliver ( struct pxe_udp_connection *  pxe_udp, struct io_buffer *  iobuf, struct xfer_metadata *  meta  )

static

Receive PXE UDP data.

Parameters

pxe_udp	PXE UDP connection
iobuf	I/O buffer
meta	Data transfer metadata

Return values

rc	Return status code

Receives a packet as part of the current pxenv_udp_read() operation.

Definition at line 77 of file pxe_udp.c.

                                                          {
        struct pxe_udp_pseudo_header *pshdr;
        struct sockaddr_in *sin_src;
        struct sockaddr_in *sin_dest;
        int rc;

        /* Extract metadata */
        assert ( meta );
        sin_src = ( struct sockaddr_in * ) meta->src;
        assert ( sin_src );
        assert ( sin_src->sin_family == AF_INET );
        sin_dest = ( struct sockaddr_in * ) meta->dest;
        assert ( sin_dest );
        assert ( sin_dest->sin_family == AF_INET );

        /* Construct pseudo-header */
        if ( ( rc = iob_ensure_headroom ( iobuf, sizeof ( *pshdr ) ) ) != 0 ) {
                DBG ( "PXE could not prepend pseudo-header\n" );
                rc = -ENOMEM;
                goto drop;
        }
        pshdr = iob_push ( iobuf, sizeof ( *pshdr ) );
        pshdr->src_ip = sin_src->sin_addr.s_addr;
        pshdr->s_port = sin_src->sin_port;
        pshdr->dest_ip = sin_dest->sin_addr.s_addr;
        pshdr->d_port = sin_dest->sin_port;

        /* Add to queue */
        list_add_tail ( &iobuf->list, &pxe_udp->list );

        return 0;

 drop:
        free_iob ( iobuf );
        return rc;
}

References AF_INET, assert(), pxe_udp_pseudo_header::d_port, DBG, pxe_udp_pseudo_header::dest_ip, ENOMEM, free_iob(), iob_ensure_headroom(), iob_push, pxe_udp_connection::list, io_buffer::list, list_add_tail, meta(), pxe_udp, rc, in_addr::s_addr, pxe_udp_pseudo_header::s_port, sockaddr_in::sin_addr, sockaddr_in::sin_family, sockaddr_in::sin_port, and pxe_udp_pseudo_header::src_ip.

pxenv_udp_open()

static PXENV_EXIT_t pxenv_udp_open ( struct s_PXENV_UDP_OPEN *  pxenv_udp_open )

static

UDP OPEN.

Parameters

pxenv_udp_open	Pointer to a struct s_PXENV_UDP_OPEN
s_PXENV_UDP_OPEN::src_ip	IP address of this station, or 0.0.0.0

Return values

PXENV_EXIT_SUCCESS	Always
s_PXENV_UDP_OPEN::Status	PXE status code

Exceptions

PXENV_STATUS_UDP_OPEN	UDP connection already open
PXENV_STATUS_OUT_OF_RESOURCES	Could not open connection

Prepares the PXE stack for communication using pxenv_udp_write() and pxenv_udp_read().

The IP address supplied in s_PXENV_UDP_OPEN::src_ip will be recorded and used as the local station's IP address for all further communication, including communication by means other than pxenv_udp_write() and pxenv_udp_read(). (If s_PXENV_UDP_OPEN::src_ip is 0.0.0.0, the local station's IP address will remain unchanged.)

You can only have one open UDP connection at a time. This is not a meaningful restriction, since pxenv_udp_write() and pxenv_udp_read() allow you to specify arbitrary local and remote ports and an arbitrary remote address for each packet. According to the PXE specifiation, you cannot have a UDP connection open at the same time as a TFTP connection; this restriction does not apply to Etherboot.

On x86, you must set the s_PXE::StatusCallout field to a nonzero value before calling this function in protected mode. You cannot call this function with a 32-bit stack segment. (See the relevant implementation note for more details.)

Note

The PXE specification does not make it clear whether the IP address supplied in s_PXENV_UDP_OPEN::src_ip should be used only for this UDP connection, or retained for all future communication. The latter seems more consistent with typical PXE stack behaviour.

Etherboot currently ignores the s_PXENV_UDP_OPEN::src_ip parameter.

Definition at line 176 of file pxe_udp.c.

                                                                               {
        int rc;

        DBG ( "PXENV_UDP_OPEN" );

        /* Record source IP address */
        pxe_udp.local.sin_addr.s_addr = pxenv_udp_open->src_ip;
        DBG ( " %s\n", inet_ntoa ( pxe_udp.local.sin_addr ) );

        /* Open network device, if necessary */
        if ( pxe_netdev && ( ! netdev_is_open ( pxe_netdev ) ) &&
             ( ( rc = netdev_open ( pxe_netdev ) ) != 0 ) ) {
                DBG ( "PXENV_UDP_OPEN could not (implicitly) open %s: %s\n",
                      pxe_netdev->name, strerror ( rc ) );
                pxenv_udp_open->Status = PXENV_STATUS ( rc );
                return PXENV_EXIT_FAILURE;
        }

        /* Open promiscuous UDP connection */
        intf_restart ( &pxe_udp.xfer, 0 );
        if ( ( rc = udp_open_promisc ( &pxe_udp.xfer ) ) != 0 ) {
                DBG ( "PXENV_UDP_OPEN could not open promiscuous socket: %s\n",
                      strerror ( rc ) );
                pxenv_udp_open->Status = PXENV_STATUS ( rc );
                return PXENV_EXIT_FAILURE;
        }

        pxenv_udp_open->Status = PXENV_STATUS_SUCCESS;
        return PXENV_EXIT_SUCCESS;
}

References DBG, inet_ntoa(), intf_restart(), pxe_udp_connection::local, net_device::name, netdev_is_open(), netdev_open(), pxe_netdev, pxe_udp, PXENV_EXIT_FAILURE, PXENV_EXIT_SUCCESS, PXENV_STATUS, PXENV_STATUS_SUCCESS, rc, in_addr::s_addr, sockaddr_in::sin_addr, strerror(), udp_open_promisc(), and pxe_udp_connection::xfer.

pxenv_udp_close()

static PXENV_EXIT_t pxenv_udp_close ( struct s_PXENV_UDP_CLOSE *  pxenv_udp_close )

static

UDP CLOSE.

Parameters

pxenv_udp_close

Pointer to a struct s_PXENV_UDP_CLOSE

Return values

PXENV_EXIT_SUCCESS	Always
s_PXENV_UDP_CLOSE::Status	PXE status code

Exceptions

None

-

Closes a UDP connection opened with pxenv_udp_open().

You can only have one open UDP connection at a time. You cannot have a UDP connection open at the same time as a TFTP connection. You cannot use pxenv_udp_close() to close a TFTP connection; use pxenv_tftp_close() instead.

On x86, you must set the s_PXE::StatusCallout field to a nonzero value before calling this function in protected mode. You cannot call this function with a 32-bit stack segment. (See the relevant implementation note for more details.)

Definition at line 229 of file pxe_udp.c.

                                                              {
        struct io_buffer *iobuf;
        struct io_buffer *tmp;

        DBG ( "PXENV_UDP_CLOSE\n" );

        /* Close UDP connection */
        intf_restart ( &pxe_udp.xfer, 0 );

        /* Discard any received packets */
        list_for_each_entry_safe ( iobuf, tmp, &pxe_udp.list, list ) {
                list_del ( &iobuf->list );
                free_iob ( iobuf );
        }

        pxenv_udp_close->Status = PXENV_STATUS_SUCCESS;
        return PXENV_EXIT_SUCCESS;
}

References DBG, free_iob(), intf_restart(), pxe_udp_connection::list, io_buffer::list, list_del, list_for_each_entry_safe, pxe_udp, PXENV_EXIT_SUCCESS, PXENV_STATUS_SUCCESS, tmp, and pxe_udp_connection::xfer.

pxenv_udp_write()

static PXENV_EXIT_t pxenv_udp_write ( struct s_PXENV_UDP_WRITE *  pxenv_udp_write )

static

UDP WRITE.

Parameters

pxenv_udp_write	Pointer to a struct s_PXENV_UDP_WRITE
s_PXENV_UDP_WRITE::ip	Destination IP address
s_PXENV_UDP_WRITE::gw	Relay agent IP address, or 0.0.0.0
s_PXENV_UDP_WRITE::src_port	Source UDP port, or 0
s_PXENV_UDP_WRITE::dst_port	Destination UDP port
s_PXENV_UDP_WRITE::buffer_size	Length of the UDP payload
s_PXENV_UDP_WRITE::buffer	Address of the UDP payload

Return values

PXENV_EXIT_SUCCESS	Packet was transmitted successfully
PXENV_EXIT_FAILURE	Packet could not be transmitted
s_PXENV_UDP_WRITE::Status	PXE status code

Exceptions

PXENV_STATUS_UDP_CLOSED	UDP connection is not open
PXENV_STATUS_UNDI_TRANSMIT_ERROR	Could not transmit packet

Transmits a single UDP packet. A valid IP and UDP header will be prepended to the payload in s_PXENV_UDP_WRITE::buffer; the buffer should not contain precomputed IP and UDP headers, nor should it contain space allocated for these headers. The first byte of the buffer will be transmitted as the first byte following the UDP header.

If s_PXENV_UDP_WRITE::gw is 0.0.0.0, normal IP routing will take place. See the relevant implementation note for more details.

If s_PXENV_UDP_WRITE::src_port is 0, port 2069 will be used.

You must have opened a UDP connection with pxenv_udp_open() before calling pxenv_udp_write().

On x86, you must set the s_PXE::StatusCallout field to a nonzero value before calling this function in protected mode. You cannot call this function with a 32-bit stack segment. (See the relevant implementation note for more details.)

Note

Etherboot currently ignores the s_PXENV_UDP_WRITE::gw parameter.

Definition at line 290 of file pxe_udp.c.

                                                              {
        struct sockaddr_in dest;
        struct xfer_metadata meta = {
                .src = ( struct sockaddr * ) &pxe_udp.local,
                .dest = ( struct sockaddr * ) &dest,
                .netdev = pxe_netdev,
        };
        size_t len;
        struct io_buffer *iobuf;
        userptr_t buffer;
        int rc;

        DBG ( "PXENV_UDP_WRITE" );

        /* Construct destination socket address */
        memset ( &dest, 0, sizeof ( dest ) );
        dest.sin_family = AF_INET;
        dest.sin_addr.s_addr = pxenv_udp_write->ip;
        dest.sin_port = pxenv_udp_write->dst_port;

        /* Set local (source) port.  PXE spec says source port is 2069
         * if not specified.  Really, this ought to be set at UDP open
         * time but hey, we didn't design this API.
         */
        pxe_udp.local.sin_port = pxenv_udp_write->src_port;
        if ( ! pxe_udp.local.sin_port )
                pxe_udp.local.sin_port = htons ( 2069 );

        /* FIXME: we ignore the gateway specified, since we're
         * confident of being able to do our own routing.  We should
         * probably allow for multiple gateways.
         */

        /* Allocate and fill data buffer */
        len = pxenv_udp_write->buffer_size;
        iobuf = xfer_alloc_iob ( &pxe_udp.xfer, len );
        if ( ! iobuf ) {
                DBG ( " out of memory\n" );
                pxenv_udp_write->Status = PXENV_STATUS_OUT_OF_RESOURCES;
                return PXENV_EXIT_FAILURE;
        }
        buffer = real_to_user ( pxenv_udp_write->buffer.segment,
                                pxenv_udp_write->buffer.offset );
        copy_from_user ( iob_put ( iobuf, len ), buffer, 0, len );

        DBG ( " %04x:%04x+%x %d->%s:%d\n", pxenv_udp_write->buffer.segment,
              pxenv_udp_write->buffer.offset, pxenv_udp_write->buffer_size,
              ntohs ( pxenv_udp_write->src_port ),
              inet_ntoa ( dest.sin_addr ),
              ntohs ( pxenv_udp_write->dst_port ) );
        
        /* Transmit packet */
        if ( ( rc = xfer_deliver ( &pxe_udp.xfer, iobuf, &meta ) ) != 0 ) {
                DBG ( "PXENV_UDP_WRITE could not transmit: %s\n",
                      strerror ( rc ) );
                pxenv_udp_write->Status = PXENV_STATUS ( rc );
                return PXENV_EXIT_FAILURE;
        }

        pxenv_udp_write->Status = PXENV_STATUS_SUCCESS;
        return PXENV_EXIT_SUCCESS;
}

References AF_INET, buffer, copy_from_user(), DBG, dest, htons, inet_ntoa(), iob_put, len, pxe_udp_connection::local, memset(), meta(), ntohs, pxe_netdev, pxe_udp, PXENV_EXIT_FAILURE, PXENV_EXIT_SUCCESS, PXENV_STATUS, PXENV_STATUS_OUT_OF_RESOURCES, PXENV_STATUS_SUCCESS, rc, real_to_user(), sockaddr_in::sin_port, strerror(), pxe_udp_connection::xfer, xfer_alloc_iob(), and xfer_deliver().

pxenv_udp_read()

static PXENV_EXIT_t pxenv_udp_read ( struct s_PXENV_UDP_READ *  pxenv_udp_read )

static

UDP READ.

Parameters

pxenv_udp_read	Pointer to a struct s_PXENV_UDP_READ
s_PXENV_UDP_READ::dest_ip	Destination IP address, or 0.0.0.0
s_PXENV_UDP_READ::d_port	Destination UDP port, or 0
s_PXENV_UDP_READ::buffer_size	Size of the UDP payload buffer
s_PXENV_UDP_READ::buffer	Address of the UDP payload buffer

Return values

PXENV_EXIT_SUCCESS	A packet has been received
PXENV_EXIT_FAILURE	No packet has been received
s_PXENV_UDP_READ::Status	PXE status code
s_PXENV_UDP_READ::src_ip	Source IP address
s_PXENV_UDP_READ::dest_ip	Destination IP address
s_PXENV_UDP_READ::s_port	Source UDP port
s_PXENV_UDP_READ::d_port	Destination UDP port
s_PXENV_UDP_READ::buffer_size	Length of UDP payload

Exceptions

PXENV_STATUS_UDP_CLOSED	UDP connection is not open
PXENV_STATUS_FAILURE	No packet was ready to read

Receive a single UDP packet. This is a non-blocking call; if no packet is ready to read, the call will return instantly with s_PXENV_UDP_READ::Status==PXENV_STATUS_FAILURE.

If s_PXENV_UDP_READ::dest_ip is 0.0.0.0, UDP packets addressed to any IP address will be accepted and may be returned to the caller.

If s_PXENV_UDP_READ::d_port is 0, UDP packets addressed to any UDP port will be accepted and may be returned to the caller.

You must have opened a UDP connection with pxenv_udp_open() before calling pxenv_udp_read().

On x86, you must set the s_PXE::StatusCallout field to a nonzero value before calling this function in protected mode. You cannot call this function with a 32-bit stack segment. (See the relevant implementation note for more details.)

Note

The PXE specification (version 2.1) does not state that we should fill in s_PXENV_UDP_READ::dest_ip and s_PXENV_UDP_READ::d_port, but Microsoft Windows' NTLDR program expects us to do so, and will fail if we don't.

Definition at line 396 of file pxe_udp.c.

                                                                               {
        struct in_addr dest_ip_wanted = { .s_addr = pxenv_udp_read->dest_ip };
        struct in_addr dest_ip;
        struct io_buffer *iobuf;
        struct pxe_udp_pseudo_header *pshdr;
        uint16_t d_port_wanted = pxenv_udp_read->d_port;
        uint16_t d_port;
        userptr_t buffer;
        size_t len;

        /* Try receiving a packet, if the queue is empty */
        if ( list_empty ( &pxe_udp.list ) )
                step();

        /* Remove first packet from the queue */
        iobuf = list_first_entry ( &pxe_udp.list, struct io_buffer, list );
        if ( ! iobuf ) {
                /* No packet received */
                DBG2 ( "PXENV_UDP_READ\n" );
                goto no_packet;
        }
        list_del ( &iobuf->list );

        /* Strip pseudo-header */
        assert ( iob_len ( iobuf ) >= sizeof ( *pshdr ) );
        pshdr = iobuf->data;
        iob_pull ( iobuf, sizeof ( *pshdr ) );
        dest_ip.s_addr = pshdr->dest_ip;
        d_port = pshdr->d_port;
        DBG ( "PXENV_UDP_READ" );

        /* Filter on destination address and/or port */
        if ( dest_ip_wanted.s_addr &&
             ( dest_ip_wanted.s_addr != dest_ip.s_addr ) ) {
                DBG ( " wrong IP %s", inet_ntoa ( dest_ip ) );
                DBG ( " (wanted %s)\n", inet_ntoa ( dest_ip_wanted ) );
                goto drop;
        }
        if ( d_port_wanted && ( d_port_wanted != d_port ) ) {
                DBG ( " wrong port %d", htons ( d_port ) );
                DBG ( " (wanted %d)\n", htons ( d_port_wanted ) );
                goto drop;
        }

        /* Copy packet to buffer and record length */
        buffer = real_to_user ( pxenv_udp_read->buffer.segment,
                                pxenv_udp_read->buffer.offset );
        len = iob_len ( iobuf );
        if ( len > pxenv_udp_read->buffer_size )
                len = pxenv_udp_read->buffer_size;
        copy_to_user ( buffer, 0, iobuf->data, len );
        pxenv_udp_read->buffer_size = len;

        /* Fill in source/dest information */
        pxenv_udp_read->src_ip = pshdr->src_ip;
        pxenv_udp_read->s_port = pshdr->s_port;
        pxenv_udp_read->dest_ip = pshdr->dest_ip;
        pxenv_udp_read->d_port = pshdr->d_port;

        DBG ( " %04x:%04x+%x %s:", pxenv_udp_read->buffer.segment,
              pxenv_udp_read->buffer.offset, pxenv_udp_read->buffer_size,
              inet_ntoa ( *( ( struct in_addr * ) &pxenv_udp_read->src_ip ) ));
        DBG ( "%d<-%s:%d\n",  ntohs ( pxenv_udp_read->s_port ),
              inet_ntoa ( *( ( struct in_addr * ) &pxenv_udp_read->dest_ip ) ),
              ntohs ( pxenv_udp_read->d_port ) );

        /* Free I/O buffer */
        free_iob ( iobuf );

        pxenv_udp_read->Status = PXENV_STATUS_SUCCESS;
        return PXENV_EXIT_SUCCESS;

 drop:
        free_iob ( iobuf );
 no_packet:
        pxenv_udp_read->Status = PXENV_STATUS_FAILURE;
        return PXENV_EXIT_FAILURE;
}

References assert(), buffer, copy_to_user(), pxe_udp_pseudo_header::d_port, d_port, io_buffer::data, DBG, DBG2, pxe_udp_pseudo_header::dest_ip, dest_ip, free_iob(), htons, inet_ntoa(), iob_len(), iob_pull, len, pxe_udp_connection::list, io_buffer::list, list_del, list_empty, list_first_entry, ntohs, pxe_udp, PXENV_EXIT_FAILURE, PXENV_EXIT_SUCCESS, PXENV_STATUS_FAILURE, PXENV_STATUS_SUCCESS, real_to_user(), in_addr::s_addr, pxe_udp_pseudo_header::s_port, pxe_udp_pseudo_header::src_ip, and step().

pxe_udp_discard()

static unsigned int pxe_udp_discard ( void  )

static

Discard some cached PXE UDP data.

Return values

discarded

Number of cached items discarded

Definition at line 492 of file pxe_udp.c.

                                             {
        struct io_buffer *iobuf;
        unsigned int discarded = 0;

        /* Try to discard the oldest received UDP packet */
        iobuf = list_first_entry ( &pxe_udp.list, struct io_buffer, list );
        if ( iobuf ) {
                list_del ( &iobuf->list );
                free_iob ( iobuf );
                discarded++;
        }

        return discarded;
}

References free_iob(), pxe_udp_connection::list, io_buffer::list, list_del, list_first_entry, and pxe_udp.

__cache_discarder()

struct cache_discarder pxe_udp_discarder __cache_discarder

(

CACHE_NORMAL

)

PXE UDP cache discarder.

Variable Documentation

pxe_udp_xfer_operations

struct interface_operation pxe_udp_xfer_operations[]

static

Initial value:

= {
        INTF_OP ( xfer_deliver, struct pxe_udp_connection *, pxe_udp_deliver ),
}

PXE UDP data transfer interface operations.

Definition at line 117 of file pxe_udp.c.

pxe_udp_xfer_desc

struct interface_descriptor pxe_udp_xfer_desc

static

Initial value:

=
        INTF_DESC ( struct pxe_udp_connection, xfer, pxe_udp_xfer_operations )

PXE UDP data transfer interface descriptor.

Definition at line 122 of file pxe_udp.c.

pxe_udp

struct pxe_udp_connection pxe_udp

static

Initial value:

= {
        .xfer = INTF_INIT ( pxe_udp_xfer_desc ),
        .local = {
                .sin_family = AF_INET,
        },
        .list = LIST_HEAD_INIT ( pxe_udp.list ),
}

The PXE UDP connection.

Definition at line 126 of file pxe_udp.c.

Referenced by pxe_udp_deliver(), pxe_udp_discard(), pxenv_udp_close(), pxenv_udp_open(), pxenv_udp_read(), and pxenv_udp_write().

__pxe_api_call

struct pxe_api_call pxe_udp_api [] __pxe_api_call

Initial value:

= {
        PXE_API_CALL ( PXENV_UDP_OPEN, pxenv_udp_open,
                       struct s_PXENV_UDP_OPEN ),
        PXE_API_CALL ( PXENV_UDP_CLOSE, pxenv_udp_close,
                       struct s_PXENV_UDP_CLOSE ),
        PXE_API_CALL ( PXENV_UDP_WRITE, pxenv_udp_write,
                       struct s_PXENV_UDP_WRITE ),
        PXE_API_CALL ( PXENV_UDP_READ, pxenv_udp_read,
                       struct s_PXENV_UDP_READ ),
}

PXE UDP API.

Definition at line 476 of file pxe_udp.c.