276 lines
7.0 KiB
C
276 lines
7.0 KiB
C
/*
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* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <string.h>
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#include <errno.h>
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#include <time.h>
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#include <ipxe/malloc.h>
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#include <ipxe/refcnt.h>
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#include <ipxe/iobuf.h>
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#include <ipxe/xfer.h>
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#include <ipxe/open.h>
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#include <ipxe/retry.h>
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#include <ipxe/timer.h>
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#include <ipxe/time.h>
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#include <ipxe/tcpip.h>
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#include <ipxe/ntp.h>
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/** @file
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*
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* Network Time Protocol
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*
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*/
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/** An NTP client */
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struct ntp_client {
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/** Reference count */
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struct refcnt refcnt;
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/** Job control interface */
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struct interface job;
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/** Data transfer interface */
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struct interface xfer;
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/** Retransmission timer */
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struct retry_timer timer;
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};
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/**
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* Close NTP client
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*
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* @v ntp NTP client
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* @v rc Reason for close
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*/
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static void ntp_close ( struct ntp_client *ntp, int rc ) {
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/* Stop timer */
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stop_timer ( &ntp->timer );
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/* Shut down interfaces */
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intf_shutdown ( &ntp->xfer, rc );
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intf_shutdown ( &ntp->job, rc );
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}
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/**
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* Send NTP request
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*
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* @v ntp NTP client
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* @ret rc Return status code
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*/
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static int ntp_request ( struct ntp_client *ntp ) {
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struct ntp_header hdr;
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int rc;
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DBGC ( ntp, "NTP %p sending request\n", ntp );
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/* Construct header */
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memset ( &hdr, 0, sizeof ( hdr ) );
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hdr.flags = ( NTP_FL_LI_UNKNOWN | NTP_FL_VN_1 | NTP_FL_MODE_CLIENT );
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hdr.transmit.seconds = htonl ( time ( NULL ) + NTP_EPOCH );
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hdr.transmit.fraction = htonl ( NTP_FRACTION_MAGIC );
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/* Send request */
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if ( ( rc = xfer_deliver_raw ( &ntp->xfer, &hdr,
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sizeof ( hdr ) ) ) != 0 ) {
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DBGC ( ntp, "NTP %p could not send request: %s\n",
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ntp, 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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* Handle NTP response
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*
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* @v ntp NTP client
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* @v iobuf I/O buffer
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* @v meta Data transfer metadata
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* @ret rc Return status code
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*/
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static int ntp_deliver ( struct ntp_client *ntp, struct io_buffer *iobuf,
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struct xfer_metadata *meta ) {
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struct ntp_header *hdr;
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struct sockaddr_tcpip *st_src;
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int32_t delta;
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int rc;
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/* Check source port */
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st_src = ( ( struct sockaddr_tcpip * ) meta->src );
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if ( st_src->st_port != htons ( NTP_PORT ) ) {
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DBGC ( ntp, "NTP %p received non-NTP packet:\n", ntp );
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DBGC_HDA ( ntp, 0, iobuf->data, iob_len ( iobuf ) );
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goto ignore;
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}
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/* Check packet length */
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if ( iob_len ( iobuf ) < sizeof ( *hdr ) ) {
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DBGC ( ntp, "NTP %p received malformed packet:\n", ntp );
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DBGC_HDA ( ntp, 0, iobuf->data, iob_len ( iobuf ) );
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goto ignore;
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}
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hdr = iobuf->data;
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/* Check mode */
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if ( ( hdr->flags & NTP_FL_MODE_MASK ) != NTP_FL_MODE_SERVER ) {
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DBGC ( ntp, "NTP %p received non-server packet:\n", ntp );
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DBGC_HDA ( ntp, 0, iobuf->data, iob_len ( iobuf ) );
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goto ignore;
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}
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/* Check magic value */
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if ( hdr->originate.fraction != htonl ( NTP_FRACTION_MAGIC ) ) {
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DBGC ( ntp, "NTP %p received unrecognised packet:\n", ntp );
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DBGC_HDA ( ntp, 0, iobuf->data, iob_len ( iobuf ) );
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goto ignore;
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}
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/* Check for Kiss-o'-Death packets */
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if ( ! hdr->stratum ) {
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DBGC ( ntp, "NTP %p received kiss-o'-death:\n", ntp );
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DBGC_HDA ( ntp, 0, iobuf->data, iob_len ( iobuf ) );
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rc = -EPROTO;
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goto close;
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}
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/* Calculate clock delta */
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delta = ( ntohl ( hdr->receive.seconds ) -
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ntohl ( hdr->originate.seconds ) );
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DBGC ( ntp, "NTP %p delta %d seconds\n", ntp, delta );
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/* Adjust system clock */
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time_adjust ( delta );
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/* Success */
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rc = 0;
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close:
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ntp_close ( ntp, rc );
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ignore:
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free_iob ( iobuf );
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return 0;
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}
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/**
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* Handle data transfer window change
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*
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* @v ntp NTP client
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*/
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static void ntp_window_changed ( struct ntp_client *ntp ) {
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/* Start timer to send initial request */
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start_timer_nodelay ( &ntp->timer );
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}
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/** Data transfer interface operations */
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static struct interface_operation ntp_xfer_op[] = {
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INTF_OP ( xfer_deliver, struct ntp_client *, ntp_deliver ),
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INTF_OP ( xfer_window_changed, struct ntp_client *,
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ntp_window_changed ),
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INTF_OP ( intf_close, struct ntp_client *, ntp_close ),
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};
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/** Data transfer interface descriptor */
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static struct interface_descriptor ntp_xfer_desc =
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INTF_DESC_PASSTHRU ( struct ntp_client, xfer, ntp_xfer_op, job );
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/** Job control interface operations */
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static struct interface_operation ntp_job_op[] = {
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INTF_OP ( intf_close, struct ntp_client *, ntp_close ),
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};
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/** Job control interface descriptor */
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static struct interface_descriptor ntp_job_desc =
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INTF_DESC_PASSTHRU ( struct ntp_client, job, ntp_job_op, xfer );
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/**
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* Handle NTP timer expiry
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*
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* @v timer Retransmission timer
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* @v fail Failure indicator
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*/
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static void ntp_expired ( struct retry_timer *timer, int fail ) {
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struct ntp_client *ntp =
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container_of ( timer, struct ntp_client, timer );
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/* Shut down client if we have failed */
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if ( fail ) {
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ntp_close ( ntp, -ETIMEDOUT );
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return;
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}
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/* Otherwise, restart timer and (re)transmit request */
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start_timer ( &ntp->timer );
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ntp_request ( ntp );
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}
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/**
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* Start NTP client
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*
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* @v job Job control interface
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* @v hostname NTP server
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* @ret rc Return status code
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*/
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int start_ntp ( struct interface *job, const char *hostname ) {
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struct ntp_client *ntp;
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union {
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struct sockaddr_tcpip st;
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struct sockaddr sa;
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} server;
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int rc;
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/* Allocate and initialise structure*/
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ntp = zalloc ( sizeof ( *ntp ) );
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if ( ! ntp ) {
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rc = -ENOMEM;
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goto err_alloc;
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}
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ref_init ( &ntp->refcnt, NULL );
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intf_init ( &ntp->job, &ntp_job_desc, &ntp->refcnt );
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intf_init ( &ntp->xfer, &ntp_xfer_desc, &ntp->refcnt );
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timer_init ( &ntp->timer, ntp_expired, &ntp->refcnt );
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set_timer_limits ( &ntp->timer, NTP_MIN_TIMEOUT, NTP_MAX_TIMEOUT );
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/* Open socket */
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memset ( &server, 0, sizeof ( server ) );
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server.st.st_port = htons ( NTP_PORT );
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if ( ( rc = xfer_open_named_socket ( &ntp->xfer, SOCK_DGRAM, &server.sa,
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hostname, NULL ) ) != 0 ) {
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DBGC ( ntp, "NTP %p could not open socket: %s\n",
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ntp, strerror ( rc ) );
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goto err_open;
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}
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/* Attach parent interface, mortalise self, and return */
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intf_plug_plug ( &ntp->job, job );
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ref_put ( &ntp->refcnt );
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return 0;
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err_open:
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ntp_close ( ntp, rc );
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ref_put ( &ntp->refcnt );
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err_alloc:
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return rc;
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}
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