From 2b03a62441d63d056dbbd6de17429ae05e4dfd04 Mon Sep 17 00:00:00 2001 From: Jim Panetta Date: Fri, 1 Nov 2013 09:59:41 -0400 Subject: NTP: Sync time correctly when receiving broadcast updates 1) The value of rtems_bsdnet_ntpserver_count is equal to 0 when no server is set, so the check for (rtems_bsdnet_ntpserver_count < 0) in rtems_bsdnet_get_ntp() is wrong. The check should be "<= 0". 2) Binding the listening socket port to 0 does not work. Packets appear on the interface, but the recvfrom in tryServer() never returns. Changing this to the well known NTP socket 123 allows the packets to be seen. 3) In tryServer(), an explicit check for NTP version 3 packets is made. If the NTP server is version 4, this check fails even though the packets seem to be the right shape. --- cpukit/libnetworking/lib/rtems_bsdnet_ntp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/cpukit/libnetworking/lib/rtems_bsdnet_ntp.c b/cpukit/libnetworking/lib/rtems_bsdnet_ntp.c index 4f991ff5b8..35092ea631 100644 --- a/cpukit/libnetworking/lib/rtems_bsdnet_ntp.c +++ b/cpukit/libnetworking/lib/rtems_bsdnet_ntp.c @@ -140,7 +140,8 @@ tryServer (int i, int s, rtems_bsdnet_ntp_callback_t callback, void *usr_data) } if ( i >= sizeof packet && - ((packet.li_vn_mode & (0x7 << 3)) == (3 << 3)) && + (((packet.li_vn_mode & (0x7 << 3)) == (3 << 3)) || + ((packet.li_vn_mode & (0x7 << 3)) == (4 << 3))) && ((packet.transmit_timestamp.integer != 0) || (packet.transmit_timestamp.fraction != 0)) && 0 == callback( &packet, 0 , usr_data) ) return 0; @@ -174,7 +175,7 @@ int ret; } memset (&myAddr, 0, sizeof myAddr); myAddr.sin_family = AF_INET; - myAddr.sin_port = htons (0); + myAddr.sin_port = htons (123); myAddr.sin_addr.s_addr = htonl (INADDR_ANY); if (bind (s, (struct sockaddr *)&myAddr, sizeof myAddr) < 0) { fprintf (stderr, "rtems_bsdnet_get_ntp() Can't bind socket: %s\n", strerror (errno)); @@ -190,7 +191,7 @@ int ret; * and hope that there's an NTP broadcast * server out there somewhere. */ - if (rtems_bsdnet_ntpserver_count < 0) { + if (rtems_bsdnet_ntpserver_count <= 0) { ret = tryServer (-1, sock, callback, usr_data); } else { -- cgit v1.2.3