ntpd/ntp_packetstamp.c

   1 /*
   2  * ntp_packetstamp.c - grubby platform-dependent details of packet timestamps
   3  *
   4  * One of our serious platform dependencies (things POSIX doesn't
   5  * specify a facility for) is isolated here.
   6  */
   7 #include "config.h"
   8
   9 #ifdef HAVE_SYS_IOCTL_H
  10 # include <sys/ioctl.h>
  11 #endif
  12
  13 #include "ntpd.h"
  14 #include "ntp_stdlib.h"
  15 #include "timespecops.h"
  16
  17 /* We handle 3 flavors of timestamp:
  18  * SO_TIMESTAMPNS/SCM_TIMESTAMPNS  Linux (maybe others)
  19  * SO_TS_CLOCK/SCM_REALTIME        FreeBSD
  20  * SO_TIMESTAMP/SCM_TIMESTAMP      Everybody else
  21  *
  22  * Linux supports both SO_TIMESTAMP and SO_TIMESTAMPNS so it's
  23  * important to check for SO_TIMESTAMPNS first to get the better accuracy.
  24  *
  25  * FreeBSD needs 2 setsockopt, SO_TIMESTAMP and SO_TS_CLOCK
  26  *
  27  * Note that the if/elif tests are done in several places.
  28  * It's important that they all check in the same order to
  29  * be consistent in case some systems support more than one.
  30  *
  31  * If SO_xxx exists, we assume that SCM_xxx does too.
  32  * All flavors assume the CMSG_xxx macros exist.
  33  *
  34  */
  35
  36
  37 void
  38 enable_packetstamps(
  39     int fd,
  40     sockaddr_u *        addr
  41     )
  42 {
  43         const int       on = 1;
  44         static bool     once = false;
  45 #if defined(SO_TS_CLOCK)
  46         const int       ts_type = SO_TS_REALTIME;
  47 #endif
  48
  49 #if defined (SO_TIMESTAMPNS)
  50         if (!once) {
  51                 once = true;
  52                 msyslog(LOG_INFO, "INIT: Using SO_TIMESTAMPNS(ns)");
  53         }
  54         if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPNS,
  55                                (const void *)&on, sizeof(on)))
  56                 msyslog(LOG_DEBUG,
  57                         "ERR: setsockopt SO_TIMESTAMPNS on fails on address %s: %s",
  58                                 socktoa(addr), strerror(errno));
  59         else
  60                 DPRINT(4, ("ERR: setsockopt SO_TIMESTAMPNS enabled on fd %d address %s\n",
  61                                     fd, socktoa(addr)));
  62 #elif defined(SO_TIMESTAMP)
  63 #if !defined(SO_TS_CLOCK)
  64         if (!once) {
  65                 once = true;
  66                 msyslog(LOG_INFO, "INIT: Using SO_TIMESTAMP(us)");
  67         }
  68 #endif
  69         if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP,
  70                                (const void*)&on, sizeof(on)))
  71                 msyslog(LOG_DEBUG,
  72                         "ERR: setsockopt SO_TIMESTAMP on fails on address %s: %s",
  73                         socktoa(addr), strerror(errno));
  74         else
  75                 DPRINT(4, ("setsockopt SO_TIMESTAMP enabled on fd %d address %s\n",
  76                             fd, socktoa(addr)));
  77 #if defined(SO_TS_CLOCK)
  78         /* FreeBSD */
  79         if (!once) {
  80                 once = true;
  81                 msyslog(LOG_INFO, "INIT: Using SO_TS_CLOCK(ns)");
  82         }
  83         if (setsockopt(fd, SOL_SOCKET, SO_TS_CLOCK,
  84                                (const void*)&ts_type, sizeof(ts_type)))
  85                 msyslog(LOG_DEBUG,
  86                         "ERR: setsockop SO_TS_CLOCK on fails on address %s: %s",
  87                         socktoa(addr), strerror(errno));
  88         else
  89                 DPRINT(4, ("setsockopt SO_TS_CLOCK enabled on fd %d address %s\n",
  90                             fd, socktoa(addr)));
  91 #endif
  92 #else
  93 # error "Can't get packet timestamp"
  94 #endif
  95 }
  96
  97
  98 /*
  99  * extract timestamps from control message buffer
 100  */
 101 l_fp
 102 fetch_packetstamp(
 103         struct msghdr *         msghdr
 104         )
 105 {
 106         struct cmsghdr *        cmsghdr;
 107 #if defined(SO_TIMESTAMPNS) || defined(SO_TS_CLOCK)
 108         struct timespec *       tsp;
 109 #elif defined(SO_TIMESTAMP)
 110         struct timeval *        tvp;
 111 #endif
 112         l_fp                    nts = 0;  /* network time stamp */
 113
 114 /* There should be only one cmsg. */
 115         cmsghdr = CMSG_FIRSTHDR(msghdr);
 116         if (NULL == cmsghdr) {
 117                 DPRINT(4, ("fetch_timestamp: can't find timestamp\n"));
 118                 msyslog(LOG_ERR, "ERR: fetch_timestamp: no msghdrs");
 119                 exit(2);
 120                 /* return ts;   ** Kludge to use time from select. */
 121         }
 122 #if defined(SO_TIMESTAMPNS)
 123         /* Linux and ?? */
 124         if (SCM_TIMESTAMPNS != cmsghdr->cmsg_type) {
 125 #elif defined(SO_TS_CLOCK)
 126         /* FreeBSD */
 127         if (SCM_REALTIME != cmsghdr->cmsg_type) {
 128 #elif defined(SO_TIMESTAMP)
 129         if (SCM_TIMESTAMP != cmsghdr->cmsg_type) {
 130 #else
 131 # error "Can't get packet timestamp"
 132 #endif
 133                 DPRINT(4,
 134                         ("fetch_timestamp: strange control message 0x%x\n",
 135                              (unsigned)cmsghdr->cmsg_type));
 136                 msyslog(LOG_ERR,
 137                         "ERR: fetch_timestamp: strange control message 0x%x",
 138                              (unsigned)cmsghdr->cmsg_type);
 139                 exit(2);
 140                 /* Could loop and skip strange types. */
 141                 /* cmsghdr = CMSG_NXTHDR(msghdr, cmsghdr); */
 142         }
 143
 144 /* cmsghdr now points to a timestamp slot */
 145
 146 #if defined(SO_TIMESTAMPNS) || defined(SO_TS_CLOCK)
 147         tsp = (struct timespec *)CMSG_DATA(cmsghdr);
 148         DPRINT(4, ("fetch_timestamp: system nsec network time stamp: %ld.%09ld\n",
 149                 (long)tsp->tv_sec, tsp->tv_nsec));
 150         nts = tspec_stamp_to_lfp(*tsp);
 151 #elif defined(SO_TIMESTAMP)
 152         tvp = (struct timeval *)CMSG_DATA(cmsghdr);
 153         DPRINT(4, ("fetch_timestamp: system usec network time stamp: %jd.%06ld\n",
 154                 (intmax_t)tvp->tv_sec, (long)tvp->tv_usec));
 155         nts = tspec_stamp_to_lfp(tval_to_tspec(*tvp));
 156 #else
 157 # error "Can't get packet timestamp"
 158 #endif
 159         return nts;
 160 }
 161
 162 // end