aa160211c2
UDP sockets can be used for multicast, at which point it becomes plausible that we could receive packets that aren't destined for us but that still match on a port number.
473 lines
12 KiB
C
473 lines
12 KiB
C
#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <byteswap.h>
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#include <errno.h>
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#include <gpxe/tcpip.h>
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#include <gpxe/iobuf.h>
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#include <gpxe/xfer.h>
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#include <gpxe/open.h>
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#include <gpxe/uri.h>
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#include <gpxe/udp.h>
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/** @file
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*
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* UDP protocol
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*/
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/**
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* A UDP connection
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*
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*/
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struct udp_connection {
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/** Reference counter */
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struct refcnt refcnt;
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/** List of UDP connections */
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struct list_head list;
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/** Data transfer interface */
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struct xfer_interface xfer;
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/** Local socket address */
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struct sockaddr_tcpip local;
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/** Remote socket address */
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struct sockaddr_tcpip peer;
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};
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/**
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* List of registered UDP connections
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*/
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static LIST_HEAD ( udp_conns );
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/* Forward declatations */
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static struct xfer_interface_operations udp_xfer_operations;
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struct tcpip_protocol udp_protocol;
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/**
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* Bind UDP connection to local port
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*
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* @v udp UDP connection
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* @ret rc Return status code
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*
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* Opens the UDP connection and binds to the specified local port. If
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* no local port is specified, the first available port will be used.
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*/
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static int udp_bind ( struct udp_connection *udp ) {
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struct udp_connection *existing;
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static uint16_t try_port = 1024;
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/* If no port specified, find the first available port */
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if ( ! udp->local.st_port ) {
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for ( ; try_port ; try_port++ ) {
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if ( try_port < 1024 )
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continue;
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udp->local.st_port = htons ( try_port );
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if ( udp_bind ( udp ) == 0 )
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return 0;
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}
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return -EADDRINUSE;
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}
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/* Attempt bind to local port */
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list_for_each_entry ( existing, &udp_conns, list ) {
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if ( existing->local.st_port == udp->local.st_port ) {
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DBGC ( udp, "UDP %p could not bind: port %d in use\n",
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udp, ntohs ( udp->local.st_port ) );
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return -EADDRINUSE;
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}
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}
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/* Add to UDP connection list */
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DBGC ( udp, "UDP %p bound to port %d\n",
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udp, ntohs ( udp->local.st_port ) );
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return 0;
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}
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/**
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* Open a UDP connection
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*
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* @v xfer Data transfer interface
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* @v peer Peer socket address, or NULL
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* @v local Local socket address, or NULL
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* @v promisc Socket is promiscuous
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* @ret rc Return status code
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*/
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static int udp_open_common ( struct xfer_interface *xfer,
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struct sockaddr *peer, struct sockaddr *local,
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int promisc ) {
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struct sockaddr_tcpip *st_peer = ( struct sockaddr_tcpip * ) peer;
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struct sockaddr_tcpip *st_local = ( struct sockaddr_tcpip * ) local;
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struct udp_connection *udp;
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int rc;
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/* Allocate and initialise structure */
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udp = zalloc ( sizeof ( *udp ) );
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if ( ! udp )
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return -ENOMEM;
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DBGC ( udp, "UDP %p allocated\n", udp );
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xfer_init ( &udp->xfer, &udp_xfer_operations, &udp->refcnt );
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if ( st_peer )
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memcpy ( &udp->peer, st_peer, sizeof ( udp->peer ) );
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if ( st_local )
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memcpy ( &udp->local, st_local, sizeof ( udp->local ) );
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/* Bind to local port */
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if ( ! promisc ) {
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if ( ( rc = udp_bind ( udp ) ) != 0 )
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goto err;
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}
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/* Attach parent interface, transfer reference to connection
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* list and return
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*/
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xfer_plug_plug ( &udp->xfer, xfer );
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list_add ( &udp->list, &udp_conns );
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return 0;
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err:
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ref_put ( &udp->refcnt );
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return rc;
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}
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/**
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* Open a UDP connection
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*
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* @v xfer Data transfer interface
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* @v peer Peer socket address
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* @v local Local socket address, or NULL
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* @ret rc Return status code
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*/
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int udp_open ( struct xfer_interface *xfer, struct sockaddr *peer,
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struct sockaddr *local ) {
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return udp_open_common ( xfer, peer, local, 0 );
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}
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/**
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* Open a promiscuous UDP connection
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*
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* @v xfer Data transfer interface
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* @ret rc Return status code
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*
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* Promiscuous UDP connections are required in order to support the
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* PXE API.
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*/
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int udp_open_promisc ( struct xfer_interface *xfer ) {
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return udp_open_common ( xfer, NULL, NULL, 1 );
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}
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/**
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* Close a UDP connection
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*
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* @v udp UDP connection
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* @v rc Reason for close
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*/
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static void udp_close ( struct udp_connection *udp, int rc ) {
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/* Close data transfer interface */
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xfer_nullify ( &udp->xfer );
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xfer_close ( &udp->xfer, rc );
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/* Remove from list of connections and drop list's reference */
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list_del ( &udp->list );
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ref_put ( &udp->refcnt );
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DBGC ( udp, "UDP %p closed\n", udp );
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}
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/**
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* Transmit data via a UDP connection to a specified address
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*
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* @v udp UDP connection
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* @v iobuf I/O buffer
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* @v src_port Source port, or 0 to use default
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* @v dest Destination address, or NULL to use default
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* @v netdev Network device, or NULL to use default
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* @ret rc Return status code
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*/
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static int udp_tx ( struct udp_connection *udp, struct io_buffer *iobuf,
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unsigned int src_port, struct sockaddr_tcpip *dest,
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struct net_device *netdev ) {
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struct udp_header *udphdr;
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size_t len;
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int rc;
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/* Check we can accommodate the header */
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if ( ( rc = iob_ensure_headroom ( iobuf, UDP_MAX_HLEN ) ) != 0 ) {
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free_iob ( iobuf );
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return rc;
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}
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/* Fill in default values if not explicitly provided */
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if ( ! src_port )
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src_port = udp->local.st_port;
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if ( ! dest )
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dest = &udp->peer;
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/* Add the UDP header */
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udphdr = iob_push ( iobuf, sizeof ( *udphdr ) );
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len = iob_len ( iobuf );
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udphdr->dest = dest->st_port;
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udphdr->src = src_port;
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udphdr->len = htons ( len );
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udphdr->chksum = 0;
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udphdr->chksum = tcpip_chksum ( udphdr, len );
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/* Dump debugging information */
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DBGC ( udp, "UDP %p TX %d->%d len %d\n", udp,
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ntohs ( udphdr->src ), ntohs ( udphdr->dest ),
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ntohs ( udphdr->len ) );
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/* Send it to the next layer for processing */
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if ( ( rc = tcpip_tx ( iobuf, &udp_protocol, dest, netdev,
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&udphdr->chksum ) ) != 0 ) {
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DBGC ( udp, "UDP %p could not transmit packet: %s\n",
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udp, strerror ( rc ) );
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return rc;
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}
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return 0;
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}
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/**
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* Identify UDP connection by local address
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*
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* @v local Local address
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* @ret udp UDP connection, or NULL
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*/
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static struct udp_connection * udp_demux ( struct sockaddr_tcpip *local ) {
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static const struct sockaddr_tcpip empty_sockaddr;
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struct udp_connection *udp;
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list_for_each_entry ( udp, &udp_conns, list ) {
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if ( ( ( udp->local.st_family == local->st_family ) ||
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( udp->local.st_family == 0 ) ) &&
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( ( udp->local.st_port == local->st_port ) ||
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( udp->local.st_port == 0 ) ) &&
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( ( memcmp ( udp->local.pad, local->pad,
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sizeof ( udp->local.pad ) ) == 0 ) ||
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( memcmp ( udp->local.pad, empty_sockaddr.pad,
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sizeof ( udp->local.pad ) ) == 0 ) ) ) {
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return udp;
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}
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}
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return NULL;
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}
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/**
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* Process a received packet
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*
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* @v iobuf I/O buffer
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* @v st_src Partially-filled source address
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* @v st_dest Partially-filled destination address
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* @v pshdr_csum Pseudo-header checksum
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* @ret rc Return status code
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*/
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static int udp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
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struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum ) {
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struct udp_header *udphdr = iobuf->data;
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struct udp_connection *udp;
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struct xfer_metadata meta;
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size_t ulen;
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unsigned int csum;
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int rc = 0;
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/* Sanity check packet */
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if ( iob_len ( iobuf ) < sizeof ( *udphdr ) ) {
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DBG ( "UDP packet too short at %zd bytes (min %zd bytes)\n",
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iob_len ( iobuf ), sizeof ( *udphdr ) );
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rc = -EINVAL;
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goto done;
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}
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ulen = ntohs ( udphdr->len );
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if ( ulen < sizeof ( *udphdr ) ) {
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DBG ( "UDP length too short at %zd bytes "
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"(header is %zd bytes)\n", ulen, sizeof ( *udphdr ) );
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rc = -EINVAL;
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goto done;
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}
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if ( ulen > iob_len ( iobuf ) ) {
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DBG ( "UDP length too long at %zd bytes (packet is %zd "
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"bytes)\n", ulen, iob_len ( iobuf ) );
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rc = -EINVAL;
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goto done;
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}
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if ( udphdr->chksum ) {
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csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data, ulen );
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if ( csum != 0 ) {
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DBG ( "UDP checksum incorrect (is %04x including "
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"checksum field, should be 0000)\n", csum );
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rc = -EINVAL;
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goto done;
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}
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}
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/* Parse parameters from header and strip header */
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st_src->st_port = udphdr->src;
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st_dest->st_port = udphdr->dest;
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udp = udp_demux ( st_dest );
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iob_unput ( iobuf, ( iob_len ( iobuf ) - ulen ) );
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iob_pull ( iobuf, sizeof ( *udphdr ) );
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/* Dump debugging information */
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DBGC ( udp, "UDP %p RX %d<-%d len %zd\n", udp,
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ntohs ( udphdr->dest ), ntohs ( udphdr->src ), ulen );
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/* Ignore if no matching connection found */
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if ( ! udp ) {
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DBG ( "No UDP connection listening on port %d\n",
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ntohs ( udphdr->dest ) );
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rc = -ENOTCONN;
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goto done;
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}
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/* Pass data to application */
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memset ( &meta, 0, sizeof ( meta ) );
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meta.src = ( struct sockaddr * ) st_src;
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meta.dest = ( struct sockaddr * ) st_dest;
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rc = xfer_deliver_iob_meta ( &udp->xfer, iobuf, &meta );
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iobuf = NULL;
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done:
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free_iob ( iobuf );
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return rc;
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}
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struct tcpip_protocol udp_protocol __tcpip_protocol = {
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.name = "UDP",
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.rx = udp_rx,
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.tcpip_proto = IP_UDP,
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};
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/***************************************************************************
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*
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* Data transfer interface
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*
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***************************************************************************
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*/
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/**
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* Close interface
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*
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* @v xfer Data transfer interface
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* @v rc Reason for close
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*/
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static void udp_xfer_close ( struct xfer_interface *xfer, int rc ) {
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struct udp_connection *udp =
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container_of ( xfer, struct udp_connection, xfer );
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/* Close connection */
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udp_close ( udp, rc );
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}
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/**
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* Allocate I/O buffer for UDP
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*
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* @v xfer Data transfer interface
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* @v len Payload size
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* @ret iobuf I/O buffer, or NULL
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*/
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static struct io_buffer * udp_alloc_iob ( struct xfer_interface *xfer,
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size_t len ) {
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struct udp_connection *udp =
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container_of ( xfer, struct udp_connection, xfer );
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struct io_buffer *iobuf;
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iobuf = alloc_iob ( UDP_MAX_HLEN + len );
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if ( ! iobuf ) {
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DBGC ( udp, "UDP %p cannot allocate buffer of length %zd\n",
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udp, len );
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return NULL;
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}
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iob_reserve ( iobuf, UDP_MAX_HLEN );
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return iobuf;
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}
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/**
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* Deliver datagram as I/O buffer
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*
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* @v xfer Data transfer interface
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* @v iobuf Datagram I/O buffer
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* @v meta Data transfer metadata, or NULL
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* @ret rc Return status code
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*/
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static int udp_xfer_deliver_iob ( struct xfer_interface *xfer,
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struct io_buffer *iobuf,
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struct xfer_metadata *meta ) {
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struct udp_connection *udp =
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container_of ( xfer, struct udp_connection, xfer );
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struct sockaddr_tcpip *src;
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struct sockaddr_tcpip *dest = NULL;
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struct net_device *netdev = NULL;
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unsigned int src_port = 0;
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/* Apply xfer metadata */
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if ( meta ) {
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src = ( struct sockaddr_tcpip * ) meta->src;
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if ( src )
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src_port = src->st_port;
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dest = ( struct sockaddr_tcpip * ) meta->dest;
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netdev = meta->netdev;
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}
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/* Transmit data, if possible */
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udp_tx ( udp, iobuf, src_port, dest, netdev );
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return 0;
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}
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/** UDP data transfer interface operations */
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static struct xfer_interface_operations udp_xfer_operations = {
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.close = udp_xfer_close,
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.vredirect = ignore_xfer_vredirect,
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.window = unlimited_xfer_window,
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.alloc_iob = udp_alloc_iob,
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.deliver_iob = udp_xfer_deliver_iob,
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.deliver_raw = xfer_deliver_as_iob,
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};
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/***************************************************************************
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*
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* Openers
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*
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***************************************************************************
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*/
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/** UDP socket opener */
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struct socket_opener udp_socket_opener __socket_opener = {
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.semantics = SOCK_DGRAM,
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.family = AF_INET,
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.open = udp_open,
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};
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char UDP_SOCK_DGRAM[1];
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/**
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* Open UDP URI
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*
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* @v xfer Data transfer interface
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* @v uri URI
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* @ret rc Return status code
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*/
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static int udp_open_uri ( struct xfer_interface *xfer, struct uri *uri ) {
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struct sockaddr_tcpip peer;
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/* Sanity check */
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if ( ! uri->host )
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return -EINVAL;
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memset ( &peer, 0, sizeof ( peer ) );
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peer.st_port = htons ( uri_port ( uri, 0 ) );
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return xfer_open_named_socket ( xfer, SOCK_DGRAM,
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( struct sockaddr * ) &peer,
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uri->host, NULL );
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}
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/** UDP URI opener */
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struct uri_opener udp_uri_opener __uri_opener = {
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.scheme = "udp",
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.open = udp_open_uri,
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};
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