udp.c File Reference

UDP protocol. More...

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <byteswap.h>
#include <errno.h>
#include <ipxe/tcpip.h>
#include <ipxe/iobuf.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/uri.h>
#include <ipxe/netdevice.h>
#include <ipxe/udp.h>

Go to the source code of this file.

Data Structures
struct	udp_connection
	A UDP connection. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static	LIST_HEAD (udp_conns)
	List of registered UDP connections. More...
static int	udp_port_available (int port)
	Check if local UDP port is available. More...
static int	udp_open_common (struct interface *xfer, struct sockaddr *peer, struct sockaddr *local, int promisc)
	Open a UDP connection. More...
int	udp_open (struct interface *xfer, struct sockaddr *peer, struct sockaddr *local)
	Open a UDP connection. More...
int	udp_open_promisc (struct interface *xfer)
	Open a promiscuous UDP connection. More...
static void	udp_close (struct udp_connection *udp, int rc)
	Close a UDP connection. More...
static int	udp_tx (struct udp_connection *udp, struct io_buffer *iobuf, struct sockaddr_tcpip *src, struct sockaddr_tcpip *dest, struct net_device *netdev)
	Transmit data via a UDP connection to a specified address. More...
static struct udp_connection *	udp_demux (struct sockaddr_tcpip *local)
	Identify UDP connection by local address. More...
static int	udp_rx (struct io_buffer *iobuf, struct net_device *netdev __unused, struct sockaddr_tcpip *st_src, struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum)
	Process a received packet. More...
static struct io_buffer *	udp_xfer_alloc_iob (struct udp_connection *udp, size_t len)
	Allocate I/O buffer for UDP. More...
static int	udp_xfer_deliver (struct udp_connection *udp, struct io_buffer *iobuf, struct xfer_metadata *meta)
	Deliver datagram as I/O buffer. More...
static int	udp_open_uri (struct interface *xfer, struct uri *uri)
	Open UDP URI. More...

Variables
static struct interface_descriptor	udp_xfer_desc
	UDP data transfer interface descriptor. More...
struct tcpip_protocol udp_protocol	__tcpip_protocol
	ICMPv4 TCP/IP protocol. More...
static struct interface_operation	udp_xfer_operations []
	UDP data transfer interface operations. More...
struct socket_opener udp_socket_opener	__socket_opener
	UDP socket opener. More...
int	udp_sock_dgram = UDP_SOCK_DGRAM
	Linkage hack. More...
struct uri_opener udp_uri_opener	__uri_opener
	UDP URI opener. More...

Detailed Description

UDP protocol.

Definition in file udp.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

LIST_HEAD()

static LIST_HEAD ( udp_conns  )

static

List of registered UDP connections.

udp_port_available()

static int udp_port_available ( int  port )

static

Check if local UDP port is available.

Parameters

port	Local port number

Return values

port	Local port number, or negative error

Definition at line 56 of file udp.c.

                                           {
        struct udp_connection *udp;

        list_for_each_entry ( udp, &udp_conns, list ) {
                if ( udp->local.st_port == htons ( port ) )
                        return -EADDRINUSE;
        }
        return port;
}

References EADDRINUSE, htons, udp_connection::list, list_for_each_entry, udp_connection::local, port, and sockaddr_tcpip::st_port.

Referenced by udp_open_common().

udp_open_common()

static int udp_open_common ( struct interface *  xfer, struct sockaddr *  peer, struct sockaddr *  local, int  promisc  )

static

Open a UDP connection.

Parameters

xfer	Data transfer interface
peer	Peer socket address, or NULL
local	Local socket address, or NULL
promisc	Socket is promiscuous

Return values

rc	Return status code

Definition at line 75 of file udp.c.

                                           {
        struct sockaddr_tcpip *st_peer = ( struct sockaddr_tcpip * ) peer;
        struct sockaddr_tcpip *st_local = ( struct sockaddr_tcpip * ) local;
        struct udp_connection *udp;
        int port;
        int rc;

        /* Allocate and initialise structure */
        udp = zalloc ( sizeof ( *udp ) );
        if ( ! udp )
                return -ENOMEM;
        DBGC ( udp, "UDP %p allocated\n", udp );
        ref_init ( &udp->refcnt, NULL );
        intf_init ( &udp->xfer, &udp_xfer_desc, &udp->refcnt );
        if ( st_peer )
                memcpy ( &udp->peer, st_peer, sizeof ( udp->peer ) );
        if ( st_local )
                memcpy ( &udp->local, st_local, sizeof ( udp->local ) );

        /* Bind to local port */
        if ( ! promisc ) {
                port = tcpip_bind ( st_local, udp_port_available );
                if ( port < 0 ) {
                        rc = port;
                        DBGC ( udp, "UDP %p could not bind: %s\n",
                               udp, strerror ( rc ) );
                        goto err;
                }
                udp->local.st_port = htons ( port );
                DBGC ( udp, "UDP %p bound to port %d\n",
                       udp, ntohs ( udp->local.st_port ) );
        }

        /* Attach parent interface, transfer reference to connection
         * list and return
         */
        intf_plug_plug ( &udp->xfer, xfer );
        list_add ( &udp->list, &udp_conns );
        return 0;

 err:
        ref_put ( &udp->refcnt );
        return rc;
}

References DBGC, ENOMEM, htons, intf_init(), intf_plug_plug(), udp_connection::list, list_add, udp_connection::local, memcpy(), ntohs, NULL, peer, udp_connection::peer, port, rc, ref_init, ref_put, udp_connection::refcnt, sockaddr_tcpip::st_port, strerror(), tcpip_bind(), udp_port_available(), udp_xfer_desc, udp_connection::xfer, and zalloc().

Referenced by udp_open(), and udp_open_promisc().

udp_open()

int udp_open	(	struct interface *	xfer,
		struct sockaddr *	peer,
		struct sockaddr *	local
	)

Open a UDP connection.

Parameters

xfer	Data transfer interface
peer	Peer socket address
local	Local socket address, or NULL

Return values

rc	Return status code

Definition at line 130 of file udp.c.

                                        {
        return udp_open_common ( xfer, peer, local, 0 );
}

References udp_connection::local, peer, udp_open_common(), and udp_connection::xfer.

udp_open_promisc()

int udp_open_promisc

(

struct interface *

xfer

)

Open a promiscuous UDP connection.

Parameters

xfer	Data transfer interface

Return values

rc	Return status code

Promiscuous UDP connections are required in order to support the PXE API.

Definition at line 144 of file udp.c.

                                                {
        return udp_open_common ( xfer, NULL, NULL, 1 );
}

References NULL, udp_open_common(), and udp_connection::xfer.

Referenced by efi_pxe_udp_open(), and pxenv_udp_open().

udp_close()

static void udp_close ( struct udp_connection *  udp, int  rc  )

static

Close a UDP connection.

Parameters

udp	UDP connection
rc	Reason for close

Definition at line 154 of file udp.c.

                                                             {

        /* Close data transfer interface */
        intf_shutdown ( &udp->xfer, rc );

        /* Remove from list of connections and drop list's reference */
        list_del ( &udp->list );
        ref_put ( &udp->refcnt );

        DBGC ( udp, "UDP %p closed\n", udp );
}

References DBGC, intf_shutdown(), udp_connection::list, list_del, rc, ref_put, udp_connection::refcnt, and udp_connection::xfer.

udp_tx()

static int udp_tx ( struct udp_connection *  udp, struct io_buffer *  iobuf, struct sockaddr_tcpip *  src, struct sockaddr_tcpip *  dest, struct net_device *  netdev  )

static

Transmit data via a UDP connection to a specified address.

Parameters

udp	UDP connection
iobuf	I/O buffer
src	Source address, or NULL to use default
dest	Destination address, or NULL to use default
netdev	Network device, or NULL to use default

Return values

rc	Return status code

Definition at line 176 of file udp.c.

                                                {
        struct udp_header *udphdr;
        size_t len;
        int rc;

        /* Check we can accommodate the header */
        if ( ( rc = iob_ensure_headroom ( iobuf,
                                          MAX_LL_NET_HEADER_LEN ) ) != 0 ) {
                free_iob ( iobuf );
                return rc;
        }

        /* Fill in default values if not explicitly provided */
        if ( ! src )
                src = &udp->local;
        if ( ! dest )
                dest = &udp->peer;

        /* Add the UDP header */
        udphdr = iob_push ( iobuf, sizeof ( *udphdr ) );
        len = iob_len ( iobuf );
        udphdr->dest = dest->st_port;
        udphdr->src = src->st_port;
        udphdr->len = htons ( len );
        udphdr->chksum = 0;
        udphdr->chksum = tcpip_chksum ( udphdr, len );

        /* Dump debugging information */
        DBGC2 ( udp, "UDP %p TX %d->%d len %d\n", udp,
                ntohs ( udphdr->src ), ntohs ( udphdr->dest ),
                ntohs ( udphdr->len ) );

        /* Send it to the next layer for processing */
        if ( ( rc = tcpip_tx ( iobuf, &udp_protocol, src, dest, netdev,
                               &udphdr->chksum ) ) != 0 ) {
                DBGC ( udp, "UDP %p could not transmit packet: %s\n",
                       udp, strerror ( rc ) );
                return rc;
        }

        return 0;
}

References udp_header::chksum, DBGC, DBGC2, udp_header::dest, dest, free_iob(), htons, iob_ensure_headroom(), iob_len(), iob_push, len, udp_header::len, udp_connection::local, MAX_LL_NET_HEADER_LEN, netdev, ntohs, udp_connection::peer, rc, udp_header::src, src, strerror(), tcpip_chksum(), and tcpip_tx().

Referenced by udp_xfer_deliver().

udp_demux()

static struct udp_connection* udp_demux ( struct sockaddr_tcpip *  local )

static

Identify UDP connection by local address.

Parameters

local

Local address

Return values

udp	UDP connection, or NULL

Definition at line 227 of file udp.c.

                                                                          {
        static const struct sockaddr_tcpip empty_sockaddr = { .pad = { 0, } };
        struct udp_connection *udp;

        list_for_each_entry ( udp, &udp_conns, list ) {
                if ( ( ( udp->local.st_family == local->st_family ) ||
                       ( udp->local.st_family == 0 ) ) &&
                     ( ( udp->local.st_port == local->st_port ) ||
                       ( udp->local.st_port == 0 ) ) &&
                     ( ( memcmp ( udp->local.pad, local->pad,
                                  sizeof ( udp->local.pad ) ) == 0 ) ||
                       ( memcmp ( udp->local.pad, empty_sockaddr.pad,
                                  sizeof ( udp->local.pad ) ) == 0 ) ) ) {
                        return udp;
                }
        }
        return NULL;
}

References udp_connection::list, list_for_each_entry, udp_connection::local, memcmp(), NULL, sockaddr_tcpip::pad, sockaddr_tcpip::st_family, and sockaddr_tcpip::st_port.

Referenced by udp_rx().

udp_rx()

static int udp_rx ( struct io_buffer *  iobuf, struct net_device *netdev  __unused, struct sockaddr_tcpip *  st_src, struct sockaddr_tcpip *  st_dest, uint16_t  pshdr_csum  )

static

Process a received packet.

Parameters

iobuf	I/O buffer
netdev	Network device
st_src	Partially-filled source address
st_dest	Partially-filled destination address
pshdr_csum	Pseudo-header checksum

Return values

rc	Return status code

Definition at line 256 of file udp.c.

                                                                          {
        struct udp_header *udphdr = iobuf->data;
        struct udp_connection *udp;
        struct xfer_metadata meta;
        size_t ulen;
        unsigned int csum;
        int rc = 0;

        /* Sanity check packet */
        if ( iob_len ( iobuf ) < sizeof ( *udphdr ) ) {
                DBG ( "UDP packet too short at %zd bytes (min %zd bytes)\n",
                      iob_len ( iobuf ), sizeof ( *udphdr ) );
                
                rc = -EINVAL;
                goto done;
        }
        ulen = ntohs ( udphdr->len );
        if ( ulen < sizeof ( *udphdr ) ) {
                DBG ( "UDP length too short at %zd bytes "
                      "(header is %zd bytes)\n", ulen, sizeof ( *udphdr ) );
                rc = -EINVAL;
                goto done;
        }
        if ( ulen > iob_len ( iobuf ) ) {
                DBG ( "UDP length too long at %zd bytes (packet is %zd "
                      "bytes)\n", ulen, iob_len ( iobuf ) );
                rc = -EINVAL;
                goto done;
        }
        if ( udphdr->chksum ) {
                csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data, ulen );
                if ( csum != 0 ) {
                        DBG ( "UDP checksum incorrect (is %04x including "
                              "checksum field, should be 0000)\n", csum );
                        rc = -EINVAL;
                        goto done;
                }
        }

        /* Parse parameters from header and strip header */
        st_src->st_port = udphdr->src;
        st_dest->st_port = udphdr->dest;
        udp = udp_demux ( st_dest );
        iob_unput ( iobuf, ( iob_len ( iobuf ) - ulen ) );
        iob_pull ( iobuf, sizeof ( *udphdr ) );

        /* Dump debugging information */
        DBGC2 ( udp, "UDP %p RX %d<-%d len %zd\n", udp,
                ntohs ( udphdr->dest ), ntohs ( udphdr->src ), ulen );

        /* Ignore if no matching connection found */
        if ( ! udp ) {
                DBG ( "No UDP connection listening on port %d\n",
                      ntohs ( udphdr->dest ) );
                rc = -ENOTCONN;
                goto done;
        }

        /* Pass data to application */
        memset ( &meta, 0, sizeof ( meta ) );
        meta.src = ( struct sockaddr * ) st_src;
        meta.dest = ( struct sockaddr * ) st_dest;
        rc = xfer_deliver ( &udp->xfer, iob_disown ( iobuf ), &meta );

 done:
        free_iob ( iobuf );
        return rc;
}

References udp_header::chksum, io_buffer::data, DBG, DBGC2, udp_header::dest, done, EINVAL, ENOTCONN, free_iob(), iob_disown, iob_len(), iob_pull, iob_unput, udp_header::len, memset(), meta(), ntohs, rc, udp_header::src, sockaddr_tcpip::st_port, tcpip_continue_chksum(), udp_demux(), udp_connection::xfer, and xfer_deliver().

udp_xfer_alloc_iob()

static struct io_buffer* udp_xfer_alloc_iob ( struct udp_connection *  udp, size_t  len  )

static

Allocate I/O buffer for UDP.

Parameters

udp	UDP connection
len	Payload size

Return values

iobuf

I/O buffer, or NULL

Definition at line 349 of file udp.c.

                                                            {
        struct io_buffer *iobuf;

        iobuf = alloc_iob ( MAX_LL_NET_HEADER_LEN + len );
        if ( ! iobuf ) {
                DBGC ( udp, "UDP %p cannot allocate buffer of length %zd\n",
                       udp, len );
                return NULL;
        }
        iob_reserve ( iobuf, MAX_LL_NET_HEADER_LEN );
        return iobuf;
}

References alloc_iob(), DBGC, iob_reserve, len, MAX_LL_NET_HEADER_LEN, and NULL.

udp_xfer_deliver()

static int udp_xfer_deliver ( struct udp_connection *  udp, struct io_buffer *  iobuf, struct xfer_metadata *  meta  )

static

Deliver datagram as I/O buffer.

Parameters

udp	UDP connection
iobuf	Datagram I/O buffer
meta	Data transfer metadata

Return values

rc	Return status code

Definition at line 371 of file udp.c.

                                                           {

        /* Transmit data, if possible */
        return udp_tx ( udp, iobuf, ( ( struct sockaddr_tcpip * ) meta->src ),
                        ( ( struct sockaddr_tcpip * ) meta->dest ),
                        meta->netdev );
}

References meta(), and udp_tx().

udp_open_uri()

static int udp_open_uri ( struct interface *  xfer, struct uri *  uri  )

static

Open UDP URI.

Parameters

xfer	Data transfer interface
uri	URI

Return values

rc	Return status code

Definition at line 415 of file udp.c.

                                                                    {
        struct sockaddr_tcpip peer;

        /* Sanity check */
        if ( ! uri->host )
                return -EINVAL;

        memset ( &peer, 0, sizeof ( peer ) );
        peer.st_port = htons ( uri_port ( uri, 0 ) );
        return xfer_open_named_socket ( xfer, SOCK_DGRAM,
                                        ( struct sockaddr * ) &peer,
                                        uri->host, NULL );
}

References EINVAL, uri::host, htons, memset(), NULL, peer, SOCK_DGRAM, uri_port(), and xfer_open_named_socket().

Variable Documentation

udp_xfer_desc

static struct interface_descriptor udp_xfer_desc

static

Initial value:

=
        INTF_DESC ( struct udp_connection, xfer, udp_xfer_operations )

UDP data transfer interface descriptor.

Definition at line 47 of file udp.c.

Referenced by udp_open_common().

__tcpip_protocol

struct tcpip_protocol udp_protocol __tcpip_protocol

Initial value:

= {
        .name = "UDP",
        .rx = udp_rx,
        .zero_csum = TCPIP_NEGATIVE_ZERO_CSUM,
        .tcpip_proto = IP_UDP,
}

ICMPv4 TCP/IP protocol.

ICMPv4 TCP/IP protocol.

Definition at line 48 of file udp.c.

udp_xfer_operations

struct interface_operation udp_xfer_operations[]

static

Initial value:

= {
        INTF_OP ( xfer_deliver, struct udp_connection *, udp_xfer_deliver ),
        INTF_OP ( xfer_alloc_iob, struct udp_connection *, udp_xfer_alloc_iob ),
        INTF_OP ( intf_close, struct udp_connection *, udp_close ),
}

UDP data transfer interface operations.

Definition at line 382 of file udp.c.

__socket_opener

struct socket_opener udp_socket_opener __socket_opener

Initial value:

= {
        .semantics      = UDP_SOCK_DGRAM,
        .open           = udp_open,
}

UDP socket opener.

Definition at line 400 of file udp.c.

__uri_opener

struct uri_opener udp_uri_opener __uri_opener

Initial value:

= {
        .scheme         = "udp",
        .open           = udp_open_uri,
}

UDP URI opener.

Definition at line 430 of file udp.c.