PXENV_UDP_READ
[PXE UDP API]

UDP READ. More...

Data Structures
struct	s_PXENV_UDP_READ
	Parameter block for pxenv_udp_read(). More...
Defines
#define	PXENV_UDP_READ   0x0032
	PXE API function code for pxenv_udp_read().
Typedefs
typedef struct s_PXENV_UDP_READ	PXENV_UDP_READ_t
Functions
PXENV_EXIT_t	pxenv_udp_read (struct s_PXENV_UDP_READ *udp_read)
	UDP READ.

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Detailed Description

UDP READ.

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Define Documentation

#define PXENV_UDP_READ   0x0032

PXE API function code for pxenv_udp_read().

Definition at line 811 of file pxe_api.h.

Referenced by pxe_api_call().

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Typedef Documentation

typedef struct s_PXENV_UDP_READ PXENV_UDP_READ_t

Definition at line 824 of file pxe_api.h.

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Function Documentation

PXENV_EXIT_t pxenv_udp_read

(

struct s_PXENV_UDP_READ *

pxenv_udp_read

)

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 360 of file pxe_udp.c.

References s_PXENV_UDP_READ::buffer, s_PXENV_UDP_READ::buffer_size, s_PXENV_UDP_READ::d_port, DBG, s_PXENV_UDP_READ::dest_ip, htons, inet_ntoa(), ntohs, NULL, s_SEGOFF16::offset, PXENV_EXIT_FAILURE, PXENV_EXIT_SUCCESS, PXENV_STATUS_FAILURE, PXENV_STATUS_SUCCESS, pxe_udp_connection::pxenv_udp_read, in_addr::s_addr, s_PXENV_UDP_READ::s_port, s_SEGOFF16::segment, s_PXENV_UDP_READ::src_ip, s_PXENV_UDP_READ::Status, and step().

Referenced by pxe_api_call(), and pxe_udp_deliver_iob().

                                                                        {
        struct in_addr dest_ip_wanted = { .s_addr = pxenv_udp_read->dest_ip };
        struct in_addr dest_ip;
        uint16_t d_port_wanted = pxenv_udp_read->d_port;
        uint16_t d_port;

        DBG ( "PXENV_UDP_READ" );

        /* Try receiving a packet */
        pxe_udp.pxenv_udp_read = pxenv_udp_read;
        step();
        if ( pxe_udp.pxenv_udp_read ) {
                /* No packet received */
                pxe_udp.pxenv_udp_read = NULL;
                goto no_packet;
        }
        dest_ip.s_addr = pxenv_udp_read->dest_ip;
        d_port = pxenv_udp_read->d_port;

        /* 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)", inet_ntoa ( dest_ip_wanted ) );
                goto no_packet;
        }
        if ( d_port_wanted && ( d_port_wanted != d_port ) ) {
                DBG ( " wrong port %d ", htons ( d_port ) );
                DBG ( " (wanted %d)", htons ( d_port_wanted ) );
                goto no_packet;
        }

        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",  ntohs ( pxenv_udp_read->s_port ),
              inet_ntoa ( *( ( struct in_addr * ) &pxenv_udp_read->dest_ip ) ),
              ntohs ( pxenv_udp_read->d_port ) );

        pxenv_udp_read->Status = PXENV_STATUS_SUCCESS;
        return PXENV_EXIT_SUCCESS;

 no_packet:
        pxenv_udp_read->Status = PXENV_STATUS_FAILURE;
        return PXENV_EXIT_FAILURE;
}