Adding upstream version 4.5.upstream/4.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1561 insertions, 0 deletions

diff --git a/ntp_sources.c b/ntp_sources.c
new file mode 100644
index 0000000..d8bd2d8
--- /dev/null
+++ b/ntp_sources.c
@@ -0,0 +1,1561 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Richard P. Curnow  1997-2003
+ * Copyright (C) Miroslav Lichvar  2011-2012, 2014, 2016, 2020-2023
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Functions which manage the pool of NTP sources that we are currently
+  a client of or peering with.
+
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "array.h"
+#include "conf.h"
+#include "ntp_sources.h"
+#include "ntp_core.h"
+#include "ntp_io.h"
+#include "util.h"
+#include "logging.h"
+#include "local.h"
+#include "memory.h"
+#include "nameserv_async.h"
+#include "privops.h"
+#include "sched.h"
+
+/* ================================================== */
+
+/* Maximum number of sources */
+#define MAX_SOURCES 65536
+
+/* Record type private to this file, used to store information about
+   particular sources */
+typedef struct {
+  NTP_Remote_Address *remote_addr; /* The address of this source, non-NULL
+                                      means this slot in table is in use
+                                      (an IPADDR_ID address means the address
+                                      is not resolved yet) */
+  NCR_Instance data;            /* Data for the protocol engine for this source */
+  char *name;                   /* Name of the source as it was specified
+                                   (may be an IP address) */
+  IPAddr resolved_addr;         /* Address resolved from the name, which can be
+                                   different from remote_addr (e.g. NTS-KE) */
+  int pool_id;                  /* ID of the pool from which was this source
+                                   added or INVALID_POOL */
+  int tentative;                /* Flag indicating there was no valid response
+                                   received from the source yet */
+  uint32_t conf_id;             /* Configuration ID, which can be shared with
+                                   different sources in case of a pool */
+  double last_resolving;        /* Time of last name resolving (monotonic) */
+} SourceRecord;
+
+/* Hash table of SourceRecord, its size is a power of two and it's never
+   more than half full */
+static ARR_Instance records;
+
+/* Number of sources in the hash table */
+static int n_sources;
+
+/* Flag indicating new sources will be started automatically when added */
+static int auto_start_sources = 0;
+
+/* Flag indicating a record is currently being modified */
+static int record_lock;
+
+/* Last assigned address ID */
+static uint32_t last_address_id = 0;
+
+/* Last assigned configuration ID */
+static uint32_t last_conf_id = 0;
+
+/* Source scheduled for name resolving (first resolving or replacement) */
+struct UnresolvedSource {
+  /* Current address of the source (IPADDR_ID is used for a single source
+     with unknown address and IPADDR_UNSPEC for a pool of sources) */
+  NTP_Remote_Address address;
+  /* ID of the pool if not a single source */
+  int pool_id;
+  /* Name to be resolved */
+  char *name;
+  /* Flag indicating addresses should be used in a random order */
+  int random_order;
+  /* Flag indicating current address should be replaced only if it is
+     no longer returned by the resolver */
+  int refreshment;
+  /* Next unresolved source in the list */
+  struct UnresolvedSource *next;
+};
+
+#define RESOLVE_INTERVAL_UNIT 7
+#define MIN_RESOLVE_INTERVAL 2
+#define MAX_RESOLVE_INTERVAL 9
+#define MAX_REPLACEMENT_INTERVAL 9
+
+static struct UnresolvedSource *unresolved_sources = NULL;
+static int resolving_interval = 0;
+static int resolving_restart = 0;
+static SCH_TimeoutID resolving_id;
+static struct UnresolvedSource *resolving_source = NULL;
+static NSR_SourceResolvingEndHandler resolving_end_handler = NULL;
+
+#define MAX_POOL_SOURCES 16
+#define INVALID_POOL (-1)
+
+/* Pool of sources with the same name */
+struct SourcePool {
+  /* Number of all sources from the pool */
+  int sources;
+  /* Number of sources with unresolved address */
+  int unresolved_sources;
+  /* Number of non-tentative sources */
+  int confirmed_sources;
+  /* Maximum number of confirmed sources */
+  int max_sources;
+};
+
+/* Array of SourcePool (indexed by their ID) */
+static ARR_Instance pools;
+
+/* Requested update of a source's address */
+struct AddressUpdate {
+  NTP_Remote_Address old_address;
+  NTP_Remote_Address new_address;
+};
+
+/* Update saved when record_lock is true */
+static struct AddressUpdate saved_address_update;
+
+/* ================================================== */
+/* Forward prototypes */
+
+static void resolve_sources(void);
+static void rehash_records(void);
+static void handle_saved_address_update(void);
+static void clean_source_record(SourceRecord *record);
+static void remove_pool_sources(int pool_id, int tentative, int unresolved);
+static void remove_unresolved_source(struct UnresolvedSource *us);
+
+static void
+slew_sources(struct timespec *raw,
+             struct timespec *cooked,
+             double dfreq,
+             double doffset,
+             LCL_ChangeType change_type,
+             void *anything);
+
+/* ================================================== */
+
+/* Flag indicating whether module is initialised */
+static int initialised = 0;
+
+/* ================================================== */
+
+static SourceRecord *
+get_record(unsigned index)
+{
+  return (SourceRecord *)ARR_GetElement(records, index);
+}
+
+/* ================================================== */
+
+static struct SourcePool *
+get_pool(unsigned index)
+{
+  return (struct SourcePool *)ARR_GetElement(pools, index);
+}
+
+/* ================================================== */
+
+void
+NSR_Initialise(void)
+{
+  n_sources = 0;
+  resolving_id = 0;
+  initialised = 1;
+
+  records = ARR_CreateInstance(sizeof (SourceRecord));
+  rehash_records();
+
+  pools = ARR_CreateInstance(sizeof (struct SourcePool));
+
+  LCL_AddParameterChangeHandler(slew_sources, NULL);
+}
+
+/* ================================================== */
+
+void
+NSR_Finalise(void)
+{
+  NSR_RemoveAllSources();
+
+  LCL_RemoveParameterChangeHandler(slew_sources, NULL);
+
+  ARR_DestroyInstance(records);
+  ARR_DestroyInstance(pools);
+
+  SCH_RemoveTimeout(resolving_id);
+  while (unresolved_sources)
+    remove_unresolved_source(unresolved_sources);
+
+  initialised = 0;
+}
+
+/* ================================================== */
+/* Find a slot matching an IP address.  It is assumed that there can
+   only ever be one record for a particular IP address. */
+
+static int
+find_slot(IPAddr *ip_addr, int *slot)
+{
+  SourceRecord *record;
+  uint32_t hash;
+  unsigned int i, size;
+
+  size = ARR_GetSize(records);
+
+  *slot = 0;
+  
+  switch (ip_addr->family) {
+    case IPADDR_INET4:
+    case IPADDR_INET6:
+    case IPADDR_ID:
+      break;
+    default:
+      return 0;
+  }
+
+  hash = UTI_IPToHash(ip_addr);
+
+  for (i = 0; i < size / 2; i++) {
+    /* Use quadratic probing */
+    *slot = (hash + (i + i * i) / 2) % size;
+    record = get_record(*slot);
+
+    if (!record->remote_addr)
+      break;
+
+    if (UTI_CompareIPs(&record->remote_addr->ip_addr, ip_addr, NULL) == 0)
+      return 1;
+  }
+
+  return 0;
+}
+
+/* ================================================== */
+/* Find a slot matching an IP address and port. The function returns:
+   0 => IP not matched, empty slot returned if a valid address was provided
+   1 => Only IP matched, port doesn't match
+   2 => Both IP and port matched. */
+
+static int
+find_slot2(NTP_Remote_Address *remote_addr, int *slot)
+{
+  if (!find_slot(&remote_addr->ip_addr, slot))
+    return 0;
+
+  return get_record(*slot)->remote_addr->port == remote_addr->port ? 2 : 1;
+}
+
+/* ================================================== */
+/* Check if hash table of given size is sufficient to contain sources */
+
+static int
+check_hashtable_size(unsigned int sources, unsigned int size)
+{
+  return sources * 2 <= size;
+}
+
+/* ================================================== */
+
+static void
+rehash_records(void)
+{
+  SourceRecord *temp_records;
+  unsigned int i, old_size, new_size;
+  int slot;
+
+  assert(!record_lock);
+
+  old_size = ARR_GetSize(records);
+
+  temp_records = MallocArray(SourceRecord, old_size);
+  memcpy(temp_records, ARR_GetElements(records), old_size * sizeof (SourceRecord));
+
+  /* The size of the hash table is always a power of two */
+  for (new_size = 1; !check_hashtable_size(n_sources, new_size); new_size *= 2)
+    ;
+
+  ARR_SetSize(records, new_size);
+
+  for (i = 0; i < new_size; i++)
+    get_record(i)->remote_addr = NULL;
+
+  for (i = 0; i < old_size; i++) {
+    if (!temp_records[i].remote_addr)
+      continue;
+
+    if (find_slot2(temp_records[i].remote_addr, &slot) != 0)
+      assert(0);
+
+    *get_record(slot) = temp_records[i];
+  }
+
+  Free(temp_records);
+}
+
+/* ================================================== */
+
+static void
+log_source(SourceRecord *record, int addition, int once_per_pool)
+{
+  int pool, log_addr;
+  char *ip_str;
+
+  if (once_per_pool && record->pool_id != INVALID_POOL) {
+    if (get_pool(record->pool_id)->sources > 1)
+      return;
+    pool = 1;
+    log_addr = 0;
+  } else {
+    ip_str = UTI_IPToString(&record->remote_addr->ip_addr);
+    pool = 0;
+    log_addr = strcmp(record->name, ip_str) != 0;
+  }
+
+  LOG(LOG_GetContextSeverity(LOGC_Command | LOGC_SourceFile), "%s %s %s%s%s%s",
+      addition ? "Added" : "Removed", pool ? "pool" : "source",
+      log_addr ? ip_str : record->name,
+      log_addr ? " (" : "", log_addr ? record->name : "", log_addr ? ")" : "");
+}
+
+/* ================================================== */
+
+/* Procedure to add a new source */
+static NSR_Status
+add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type,
+           SourceParameters *params, int pool_id, uint32_t conf_id)
+{
+  SourceRecord *record;
+  int slot;
+
+  assert(initialised);
+
+  /* Find empty bin & check that we don't have the address already */
+  if (find_slot2(remote_addr, &slot) != 0) {
+    return NSR_AlreadyInUse;
+  } else if (!name && !UTI_IsIPReal(&remote_addr->ip_addr)) {
+    /* Name is required for non-real addresses */
+    return NSR_InvalidName;
+  } else if (n_sources >= MAX_SOURCES) {
+    return NSR_TooManySources;
+  } else {
+    if (remote_addr->ip_addr.family != IPADDR_INET4 &&
+        remote_addr->ip_addr.family != IPADDR_INET6 &&
+        remote_addr->ip_addr.family != IPADDR_ID) {
+      return NSR_InvalidAF;
+    } else {
+      n_sources++;
+
+      if (!check_hashtable_size(n_sources, ARR_GetSize(records))) {
+        rehash_records();
+        if (find_slot2(remote_addr, &slot) != 0)
+          assert(0);
+      }
+
+      assert(!record_lock);
+      record_lock = 1;
+
+      record = get_record(slot);
+      record->name = Strdup(name ? name : UTI_IPToString(&remote_addr->ip_addr));
+      record->data = NCR_CreateInstance(remote_addr, type, params, record->name);
+      record->remote_addr = NCR_GetRemoteAddress(record->data);
+      record->resolved_addr = remote_addr->ip_addr;
+      record->pool_id = pool_id;
+      record->tentative = 1;
+      record->conf_id = conf_id;
+      record->last_resolving = SCH_GetLastEventMonoTime();
+
+      record_lock = 0;
+
+      if (record->pool_id != INVALID_POOL) {
+        get_pool(record->pool_id)->sources++;
+        if (!UTI_IsIPReal(&remote_addr->ip_addr))
+          get_pool(record->pool_id)->unresolved_sources++;
+      }
+
+      if (auto_start_sources && UTI_IsIPReal(&remote_addr->ip_addr))
+        NCR_StartInstance(record->data);
+
+      log_source(record, 1, 1);
+
+      /* The new instance is allowed to change its address immediately */
+      handle_saved_address_update();
+
+      return NSR_Success;
+    }
+  }
+}
+
+/* ================================================== */
+
+static NSR_Status
+change_source_address(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr,
+                      int replacement)
+{
+  int slot1, slot2, found;
+  SourceRecord *record;
+  LOG_Severity severity;
+  char *name;
+
+  found = find_slot2(old_addr, &slot1);
+  if (found != 2)
+    return NSR_NoSuchSource;
+
+  /* Make sure there is no other source using the new address (with the same
+     or different port), but allow a source to have its port changed */
+  found = find_slot2(new_addr, &slot2);
+  if (found == 2 || (found != 0 && slot1 != slot2))
+    return NSR_AlreadyInUse;
+
+  assert(!record_lock);
+  record_lock = 1;
+
+  record = get_record(slot1);
+  NCR_ChangeRemoteAddress(record->data, new_addr, !replacement);
+  if (replacement)
+    record->resolved_addr = new_addr->ip_addr;
+
+  if (record->remote_addr != NCR_GetRemoteAddress(record->data) ||
+      UTI_CompareIPs(&record->remote_addr->ip_addr, &new_addr->ip_addr, NULL) != 0)
+    assert(0);
+
+  if (!UTI_IsIPReal(&old_addr->ip_addr) && UTI_IsIPReal(&new_addr->ip_addr)) {
+    if (auto_start_sources)
+      NCR_StartInstance(record->data);
+    if (record->pool_id != INVALID_POOL)
+      get_pool(record->pool_id)->unresolved_sources--;
+  }
+
+  if (!record->tentative) {
+    record->tentative = 1;
+
+    if (record->pool_id != INVALID_POOL)
+      get_pool(record->pool_id)->confirmed_sources--;
+  }
+
+  record_lock = 0;
+
+  name = record->name;
+  severity = UTI_IsIPReal(&old_addr->ip_addr) ? LOGS_INFO : LOGS_DEBUG;
+
+  if (found == 0) {
+    /* The hash table must be rebuilt for the changed address */
+    rehash_records();
+
+    LOG(severity, "Source %s %s %s (%s)", UTI_IPToString(&old_addr->ip_addr),
+        replacement ? "replaced with" : "changed to",
+        UTI_IPToString(&new_addr->ip_addr), name);
+  } else {
+    LOG(severity, "Source %s (%s) changed port to %d",
+        UTI_IPToString(&new_addr->ip_addr), name, new_addr->port);
+  }
+
+  return NSR_Success;
+}
+
+/* ================================================== */
+
+static void
+handle_saved_address_update(void)
+{
+  if (!UTI_IsIPReal(&saved_address_update.old_address.ip_addr))
+    return;
+
+  if (change_source_address(&saved_address_update.old_address,
+                            &saved_address_update.new_address, 0) != NSR_Success)
+    /* This is expected to happen only if the old address is wrong */
+    LOG(LOGS_ERR, "Could not change %s to %s",
+        UTI_IPSockAddrToString(&saved_address_update.old_address),
+        UTI_IPSockAddrToString(&saved_address_update.new_address));
+
+  saved_address_update.old_address.ip_addr.family = IPADDR_UNSPEC;
+}
+
+/* ================================================== */
+
+static int
+replace_source_connectable(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr)
+{
+  if (!NIO_IsServerConnectable(new_addr)) {
+    DEBUG_LOG("%s not connectable", UTI_IPToString(&new_addr->ip_addr));
+    return 0;
+  }
+
+  if (change_source_address(old_addr, new_addr, 1) == NSR_AlreadyInUse)
+    return 0;
+
+  handle_saved_address_update();
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+process_resolved_name(struct UnresolvedSource *us, IPAddr *ip_addrs, int n_addrs)
+{
+  NTP_Remote_Address old_addr, new_addr;
+  SourceRecord *record;
+  unsigned short first = 0;
+  int i, j, slot;
+
+  /* Keep using the current address if it is being refreshed and it is
+     still included in the resolved addresses */
+  if (us->refreshment) {
+    assert(us->pool_id == INVALID_POOL);
+
+    for (i = 0; i < n_addrs; i++) {
+      if (find_slot2(&us->address, &slot) == 2 &&
+          UTI_CompareIPs(&get_record(slot)->resolved_addr, &ip_addrs[i], NULL) == 0) {
+        DEBUG_LOG("%s still fresh", UTI_IPToString(&us->address.ip_addr));
+        return;
+      }
+    }
+  }
+
+  if (us->random_order)
+    UTI_GetRandomBytes(&first, sizeof (first));
+
+  for (i = 0; i < n_addrs; i++) {
+    new_addr.ip_addr = ip_addrs[((unsigned int)i + first) % n_addrs];
+
+    DEBUG_LOG("(%d) %s", i + 1, UTI_IPToString(&new_addr.ip_addr));
+
+    if (us->pool_id != INVALID_POOL) {
+      /* In the pool resolving mode, try to replace a source from
+         the pool which does not have a real address yet */
+      for (j = 0; j < ARR_GetSize(records); j++) {
+        record = get_record(j);
+        if (!record->remote_addr || record->pool_id != us->pool_id ||
+            UTI_IsIPReal(&record->remote_addr->ip_addr))
+          continue;
+        old_addr = *record->remote_addr;
+        new_addr.port = old_addr.port;
+        if (replace_source_connectable(&old_addr, &new_addr))
+          ;
+        break;
+      }
+    } else {
+      new_addr.port = us->address.port;
+      if (replace_source_connectable(&us->address, &new_addr))
+        break;
+    }
+  }
+}
+
+/* ================================================== */
+
+static int
+is_resolved(struct UnresolvedSource *us)
+{
+  int slot;
+
+  if (us->pool_id != INVALID_POOL) {
+    return get_pool(us->pool_id)->unresolved_sources <= 0;
+  } else {
+    /* If the address is no longer present, it was removed or replaced
+       (i.e. resolved) */
+    return find_slot2(&us->address, &slot) == 0;
+  }
+}
+
+/* ================================================== */
+
+static void
+resolve_sources_timeout(void *arg)
+{
+  resolving_id = 0;
+  resolve_sources();
+}
+
+/* ================================================== */
+
+static void
+name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *anything)
+{
+  struct UnresolvedSource *us, *next;
+
+  us = (struct UnresolvedSource *)anything;
+
+  assert(us == resolving_source);
+  assert(resolving_id == 0);
+
+  DEBUG_LOG("%s resolved to %d addrs", us->name, n_addrs);
+
+  switch (status) {
+    case DNS_TryAgain:
+      break;
+    case DNS_Success:
+      process_resolved_name(us, ip_addrs, n_addrs);
+      break;
+    case DNS_Failure:
+      LOG(LOGS_WARN, "Invalid host %s", us->name);
+      break;
+    default:
+      assert(0);
+  }
+
+  next = us->next;
+
+  /* Don't repeat the resolving if it (permanently) failed, it was a
+     replacement of a real address, or all addresses are already resolved */
+  if (status == DNS_Failure || UTI_IsIPReal(&us->address.ip_addr) || is_resolved(us))
+    remove_unresolved_source(us);
+
+  /* If a restart was requested and this was the last source in the list,
+     start with the first source again (if there still is one) */
+  if (!next && resolving_restart) {
+    next = unresolved_sources;
+    resolving_restart = 0;
+  }
+
+  resolving_source = next;
+
+  if (next) {
+    /* Continue with the next source in the list */
+    DEBUG_LOG("resolving %s", next->name);
+    DNS_Name2IPAddressAsync(next->name, name_resolve_handler, next);
+  } else {
+    /* This was the last source in the list. If some sources couldn't
+       be resolved, try again in exponentially increasing interval. */
+    if (unresolved_sources) {
+      resolving_interval = CLAMP(MIN_RESOLVE_INTERVAL, resolving_interval + 1,
+                                 MAX_RESOLVE_INTERVAL);
+      resolving_id = SCH_AddTimeoutByDelay(RESOLVE_INTERVAL_UNIT * (1 << resolving_interval),
+                                           resolve_sources_timeout, NULL);
+    } else {
+      resolving_interval = 0;
+    }
+
+    /* This round of resolving is done */
+    if (resolving_end_handler)
+      (resolving_end_handler)();
+  }
+}
+
+/* ================================================== */
+
+static void
+resolve_sources(void)
+{
+  struct UnresolvedSource *us, *next, *i;
+
+  assert(!resolving_source);
+
+  /* Remove sources that don't need to be resolved anymore */
+  for (i = unresolved_sources; i; i = next) {
+    next = i->next;
+    if (is_resolved(i))
+      remove_unresolved_source(i);
+  }
+
+  if (!unresolved_sources)
+    return;
+
+  PRV_ReloadDNS();
+
+  /* Start with the first source in the list, name_resolve_handler
+     will iterate over the rest */
+  us = unresolved_sources;
+
+  resolving_source = us;
+  DEBUG_LOG("resolving %s", us->name);
+  DNS_Name2IPAddressAsync(us->name, name_resolve_handler, us);
+}
+
+/* ================================================== */
+
+static void
+append_unresolved_source(struct UnresolvedSource *us)
+{
+  struct UnresolvedSource **i;
+
+  for (i = &unresolved_sources; *i; i = &(*i)->next)
+    ;
+  *i = us;
+  us->next = NULL;
+}
+
+/* ================================================== */
+
+static void
+remove_unresolved_source(struct UnresolvedSource *us)
+{
+  struct UnresolvedSource **i;
+
+  for (i = &unresolved_sources; *i; i = &(*i)->next) {
+    if (*i == us) {
+      *i = us->next;
+      Free(us->name);
+      Free(us);
+      break;
+    }
+  }
+}
+
+/* ================================================== */
+
+static int get_unused_pool_id(void)
+{
+  struct UnresolvedSource *us;
+  int i;
+
+  for (i = 0; i < ARR_GetSize(pools); i++) {
+    if (get_pool(i)->sources > 0)
+      continue;
+
+    /* Make sure there is no name waiting to be resolved using this pool */
+    for (us = unresolved_sources; us; us = us->next) {
+      if (us->pool_id == i)
+        break;
+    }
+    if (us)
+      continue;
+
+    return i;
+  }
+
+  return INVALID_POOL;
+}
+
+/* ================================================== */
+
+static uint32_t
+get_next_conf_id(uint32_t *conf_id)
+{
+  last_conf_id++;
+
+  if (conf_id)
+    *conf_id = last_conf_id;
+
+  return last_conf_id;
+}
+
+/* ================================================== */
+
+NSR_Status
+NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
+              SourceParameters *params, uint32_t *conf_id)
+{
+  return add_source(remote_addr, NULL, type, params, INVALID_POOL,
+                    get_next_conf_id(conf_id));
+}
+
+/* ================================================== */
+
+NSR_Status
+NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
+                    SourceParameters *params, uint32_t *conf_id)
+{
+  struct UnresolvedSource *us;
+  struct SourcePool *sp;
+  NTP_Remote_Address remote_addr;
+  int i, new_sources, pool_id;
+  uint32_t cid;
+
+  /* If the name is an IP address, add the source with the address directly */
+  if (UTI_StringToIP(name, &remote_addr.ip_addr)) {
+    remote_addr.port = port;
+    return add_source(&remote_addr, name, type, params, INVALID_POOL,
+                      get_next_conf_id(conf_id));
+  }
+
+  /* Make sure the name is at least printable and has no spaces */
+  for (i = 0; name[i] != '\0'; i++) {
+    if (!isgraph((unsigned char)name[i]))
+      return NSR_InvalidName;
+  }
+
+  us = MallocNew(struct UnresolvedSource);
+  us->name = Strdup(name);
+  us->random_order = 0;
+  us->refreshment = 0;
+
+  remote_addr.ip_addr.family = IPADDR_ID;
+  remote_addr.ip_addr.addr.id = ++last_address_id;
+  remote_addr.port = port;
+
+  if (!pool) {
+    us->pool_id = INVALID_POOL;
+    us->address = remote_addr;
+    new_sources = 1;
+  } else {
+    pool_id = get_unused_pool_id();
+    if (pool_id != INVALID_POOL) {
+      sp = get_pool(pool_id);
+    } else {
+      sp = ARR_GetNewElement(pools);
+      pool_id = ARR_GetSize(pools) - 1;
+    }
+
+    sp->sources = 0;
+    sp->unresolved_sources = 0;
+    sp->confirmed_sources = 0;
+    sp->max_sources = CLAMP(1, params->max_sources, MAX_POOL_SOURCES);
+    us->pool_id = pool_id;
+    us->address.ip_addr.family = IPADDR_UNSPEC;
+    new_sources = MIN(2 * sp->max_sources, MAX_POOL_SOURCES);
+  }
+
+  append_unresolved_source(us);
+
+  cid = get_next_conf_id(conf_id);
+
+  for (i = 0; i < new_sources; i++) {
+    if (i > 0)
+      remote_addr.ip_addr.addr.id = ++last_address_id;
+    if (add_source(&remote_addr, name, type, params, us->pool_id, cid) != NSR_Success)
+      return NSR_TooManySources;
+  }
+
+  return NSR_UnresolvedName;
+}
+
+/* ================================================== */
+
+const char *
+NSR_StatusToString(NSR_Status status)
+{
+  switch (status) {
+    case NSR_Success:
+      return "Success";
+    case NSR_NoSuchSource:
+      return "No such source";
+    case NSR_AlreadyInUse:
+      return "Already in use";
+    case NSR_TooManySources:
+      return "Too many sources";
+    case NSR_InvalidAF:
+      return "Invalid address";
+    case NSR_InvalidName:
+      return "Invalid name";
+    case NSR_UnresolvedName:
+      return "Unresolved name";
+    default:
+      return "?";
+  }
+}
+
+/* ================================================== */
+
+void
+NSR_SetSourceResolvingEndHandler(NSR_SourceResolvingEndHandler handler)
+{
+  resolving_end_handler = handler;
+}
+
+/* ================================================== */
+
+void
+NSR_ResolveSources(void)
+{
+  /* Try to resolve unresolved sources now */
+  if (unresolved_sources) {
+    /* Allow only one resolving to be running at a time */
+    if (!resolving_source) {
+      if (resolving_id != 0) {
+        SCH_RemoveTimeout(resolving_id);
+        resolving_id = 0;
+        resolving_interval--;
+      }
+      resolve_sources();
+    } else {
+      /* Try again as soon as the current resolving ends */
+      resolving_restart = 1;
+    }
+  } else {
+    /* No unresolved sources, we are done */
+    if (resolving_end_handler)
+      (resolving_end_handler)();
+  }
+}
+
+/* ================================================== */
+
+void NSR_StartSources(void)
+{
+  NTP_Remote_Address *addr;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    addr = get_record(i)->remote_addr;
+    if (!addr || !UTI_IsIPReal(&addr->ip_addr))
+      continue;
+    NCR_StartInstance(get_record(i)->data);
+  }
+}
+
+/* ================================================== */
+
+void NSR_AutoStartSources(void)
+{
+  auto_start_sources = 1;
+}
+
+/* ================================================== */
+
+static void
+clean_source_record(SourceRecord *record)
+{
+  assert(record->remote_addr);
+
+  if (record->pool_id != INVALID_POOL) {
+    struct SourcePool *pool = get_pool(record->pool_id);
+
+    pool->sources--;
+    if (!UTI_IsIPReal(&record->remote_addr->ip_addr))
+      pool->unresolved_sources--;
+    if (!record->tentative)
+      pool->confirmed_sources--;
+    if (pool->max_sources > pool->sources)
+      pool->max_sources = pool->sources;
+  }
+
+  record->remote_addr = NULL;
+  NCR_DestroyInstance(record->data);
+  Free(record->name);
+
+  n_sources--;
+}
+
+/* ================================================== */
+
+/* Procedure to remove a source.  We don't bother whether the port
+   address is matched - we're only interested in removing a record for
+   the right IP address. */
+NSR_Status
+NSR_RemoveSource(IPAddr *address)
+{
+  int slot;
+
+  assert(initialised);
+
+  if (find_slot(address, &slot) == 0)
+    return NSR_NoSuchSource;
+
+  log_source(get_record(slot), 0, 0);
+  clean_source_record(get_record(slot));
+
+  /* Rehash the table to make sure there are no broken probe sequences.
+     This is costly, but it's not expected to happen frequently. */
+
+  rehash_records();
+
+  return NSR_Success;
+}
+
+/* ================================================== */
+
+void
+NSR_RemoveSourcesById(uint32_t conf_id)
+{
+  SourceRecord *record;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr || record->conf_id != conf_id)
+      continue;
+    log_source(record, 0, 1);
+    clean_source_record(record);
+  }
+
+  rehash_records();
+}
+
+/* ================================================== */
+
+void
+NSR_RemoveAllSources(void)
+{
+  SourceRecord *record;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr)
+      continue;
+    clean_source_record(record);
+  }
+
+  rehash_records();
+}
+
+/* ================================================== */
+
+static void
+resolve_source_replacement(SourceRecord *record, int refreshment)
+{
+  struct UnresolvedSource *us;
+
+  DEBUG_LOG("%s %s (%s)", refreshment ? "refreshing" : "trying to replace",
+            UTI_IPToString(&record->remote_addr->ip_addr), record->name);
+
+  record->last_resolving = SCH_GetLastEventMonoTime();
+
+  us = MallocNew(struct UnresolvedSource);
+  us->name = Strdup(record->name);
+  /* Ignore the order of addresses from the resolver to not get
+     stuck with a pair of unreachable or otherwise unusable servers
+     (e.g. falsetickers) in case the order doesn't change, or a group
+     of servers if they are ordered by IP family */
+  us->random_order = 1;
+  us->refreshment = refreshment;
+  us->pool_id = INVALID_POOL;
+  us->address = *record->remote_addr;
+
+  append_unresolved_source(us);
+  NSR_ResolveSources();
+}
+
+/* ================================================== */
+
+void
+NSR_HandleBadSource(IPAddr *address)
+{
+  static double next_replacement = 0.0;
+  SourceRecord *record;
+  IPAddr ip_addr;
+  uint32_t rnd;
+  double now;
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return;
+
+  record = get_record(slot);
+
+  /* Don't try to replace a source specified by an IP address unless the
+     address changed since the source was added (e.g. by NTS-KE) */
+  if (UTI_StringToIP(record->name, &ip_addr) &&
+      UTI_CompareIPs(&record->remote_addr->ip_addr, &ip_addr, NULL) == 0)
+    return;
+
+  /* Don't resolve names too frequently */
+  now = SCH_GetLastEventMonoTime();
+  if (now < next_replacement) {
+    DEBUG_LOG("replacement postponed");
+    return;
+  }
+
+  UTI_GetRandomBytes(&rnd, sizeof (rnd));
+  next_replacement = now + ((double)rnd / (uint32_t)-1) *
+                     (RESOLVE_INTERVAL_UNIT * (1 << MAX_REPLACEMENT_INTERVAL));
+
+  resolve_source_replacement(record, 0);
+}
+
+/* ================================================== */
+
+static void
+maybe_refresh_source(void)
+{
+  static double last_refreshment = 0.0;
+  SourceRecord *record, *oldest_record;
+  int i, min_interval;
+  double now;
+
+  min_interval = CNF_GetRefresh();
+
+  now = SCH_GetLastEventMonoTime();
+  if (min_interval <= 0 || now < last_refreshment + min_interval)
+    return;
+
+  last_refreshment = now;
+
+  for (i = 0, oldest_record = NULL; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr || UTI_IsStringIP(record->name))
+      continue;
+
+    if (!oldest_record || oldest_record->last_resolving > record->last_resolving)
+      oldest_record = record;
+  }
+
+  if (!oldest_record)
+    return;
+
+  /* Check if the name wasn't already resolved in the last interval */
+  if (now < oldest_record->last_resolving + min_interval) {
+    last_refreshment = oldest_record->last_resolving;
+    return;
+  }
+
+  resolve_source_replacement(oldest_record, 1);
+}
+
+/* ================================================== */
+
+void
+NSR_RefreshAddresses(void)
+{
+  SourceRecord *record;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr)
+      continue;
+
+    resolve_source_replacement(record, 1);
+  }
+}
+
+/* ================================================== */
+
+NSR_Status
+NSR_UpdateSourceNtpAddress(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr)
+{
+  int slot;
+
+  if (!UTI_IsIPReal(&old_addr->ip_addr) || !UTI_IsIPReal(&new_addr->ip_addr))
+    return NSR_InvalidAF;
+
+  if (UTI_CompareIPs(&old_addr->ip_addr, &new_addr->ip_addr, NULL) != 0 &&
+      find_slot(&new_addr->ip_addr, &slot))
+    return NSR_AlreadyInUse;
+
+  /* If a record is being modified (e.g. by change_source_address(), or the
+     source is just being created), postpone the change to avoid corruption */
+
+  if (!record_lock)
+    return change_source_address(old_addr, new_addr, 0);
+
+  if (UTI_IsIPReal(&saved_address_update.old_address.ip_addr))
+    return NSR_TooManySources;
+
+  saved_address_update.old_address = *old_addr;
+  saved_address_update.new_address = *new_addr;
+
+  return NSR_Success;
+}
+
+/* ================================================== */
+
+static void remove_pool_sources(int pool_id, int tentative, int unresolved)
+{
+  SourceRecord *record;
+  unsigned int i, removed;
+
+  for (i = removed = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+
+    if (!record->remote_addr || record->pool_id != pool_id)
+      continue;
+
+    if ((tentative && !record->tentative) ||
+        (unresolved && UTI_IsIPReal(&record->remote_addr->ip_addr)))
+      continue;
+
+    DEBUG_LOG("removing %ssource %s", tentative ? "tentative " : "",
+              UTI_IPToString(&record->remote_addr->ip_addr));
+
+    clean_source_record(record);
+    removed++;
+  }
+
+  if (removed)
+    rehash_records();
+}
+
+/* ================================================== */
+
+uint32_t
+NSR_GetLocalRefid(IPAddr *address)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  return NCR_GetLocalRefid(get_record(slot)->data);
+}
+
+/* ================================================== */
+
+char *
+NSR_GetName(IPAddr *address)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return NULL;
+
+  return get_record(slot)->name;
+}
+
+/* ================================================== */
+
+/* This routine is called by ntp_io when a new packet arrives off the network,
+   possibly with an authentication tail */
+void
+NSR_ProcessRx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+              NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length)
+{
+  SourceRecord *record;
+  struct SourcePool *pool;
+  int slot;
+
+  assert(initialised);
+
+  /* Avoid unnecessary lookup if the packet cannot be a response from our
+     source.  Otherwise, it must match both IP address and port number. */
+  if (NTP_LVM_TO_MODE(message->lvm) != MODE_CLIENT &&
+      find_slot2(remote_addr, &slot) == 2) {
+    record = get_record(slot);
+
+    if (!NCR_ProcessRxKnown(record->data, local_addr, rx_ts, message, length))
+      return;
+
+    if (record->tentative) {
+      /* This was the first good reply from the source */
+      record->tentative = 0;
+
+      if (record->pool_id != INVALID_POOL) {
+        pool = get_pool(record->pool_id);
+        pool->confirmed_sources++;
+
+        DEBUG_LOG("pool %s has %d confirmed sources", record->name, pool->confirmed_sources);
+
+        /* If the number of sources from the pool reached the configured
+           maximum, remove the remaining tentative sources */
+        if (pool->confirmed_sources >= pool->max_sources)
+          remove_pool_sources(record->pool_id, 1, 0);
+      }
+    }
+
+    maybe_refresh_source();
+  } else {
+    NCR_ProcessRxUnknown(remote_addr, local_addr, rx_ts, message, length);
+  }
+}
+
+/* ================================================== */
+
+void
+NSR_ProcessTx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+              NTP_Local_Timestamp *tx_ts, NTP_Packet *message, int length)
+{
+  SourceRecord *record;
+  int slot;
+
+  /* Avoid unnecessary lookup if the packet cannot be a request to our
+     source.  Otherwise, it must match both IP address and port number. */
+  if (NTP_LVM_TO_MODE(message->lvm) != MODE_SERVER &&
+      find_slot2(remote_addr, &slot) == 2) {
+    record = get_record(slot);
+    NCR_ProcessTxKnown(record->data, local_addr, tx_ts, message, length);
+  } else {
+    NCR_ProcessTxUnknown(remote_addr, local_addr, tx_ts, message, length);
+  }
+}
+
+/* ================================================== */
+
+static void
+slew_sources(struct timespec *raw,
+             struct timespec *cooked,
+             double dfreq,
+             double doffset,
+             LCL_ChangeType change_type,
+             void *anything)
+{
+  SourceRecord *record;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (record->remote_addr) {
+      if (change_type == LCL_ChangeUnknownStep) {
+        NCR_ResetInstance(record->data);
+        NCR_ResetPoll(record->data);
+      } else {
+        NCR_SlewTimes(record->data, cooked, dfreq, doffset);
+      }
+    }
+  }
+}
+
+/* ================================================== */
+
+int
+NSR_SetConnectivity(IPAddr *mask, IPAddr *address, SRC_Connectivity connectivity)
+{
+  SourceRecord *record, *syncpeer;
+  unsigned int i, any;
+
+  if (connectivity != SRC_OFFLINE)
+    NSR_ResolveSources();
+
+  any = 0;
+  syncpeer = NULL;
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (record->remote_addr) {
+      /* Ignore SRC_MAYBE_ONLINE connectivity change for unspecified unresolved
+         sources as they would always end up in the offline state */
+      if ((address->family == IPADDR_UNSPEC &&
+           (connectivity != SRC_MAYBE_ONLINE || UTI_IsIPReal(&record->remote_addr->ip_addr))) ||
+          !UTI_CompareIPs(&record->remote_addr->ip_addr, address, mask)) {
+        any = 1;
+        if (NCR_IsSyncPeer(record->data)) {
+          syncpeer = record;
+          continue;
+        }
+        NCR_SetConnectivity(record->data, connectivity);
+      }
+    }
+  }
+
+  /* Set the sync peer last to avoid unnecessary reference switching */
+  if (syncpeer)
+    NCR_SetConnectivity(syncpeer->data, connectivity);
+
+  return any;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMinpoll(IPAddr *address, int new_minpoll)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMinpoll(get_record(slot)->data, new_minpoll);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMaxpoll(IPAddr *address, int new_maxpoll)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMaxpoll(get_record(slot)->data, new_maxpoll);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMaxdelay(IPAddr *address, double new_max_delay)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMaxdelay(get_record(slot)->data, new_max_delay);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMaxdelayratio(IPAddr *address, double new_max_delay_ratio)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMaxdelayratio(get_record(slot)->data, new_max_delay_ratio);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMaxdelaydevratio(IPAddr *address, double new_max_delay_dev_ratio)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMaxdelaydevratio(get_record(slot)->data, new_max_delay_dev_ratio);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyMinstratum(IPAddr *address, int new_min_stratum)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyMinstratum(get_record(slot)->data, new_min_stratum);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_ModifyPolltarget(IPAddr *address, int new_poll_target)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyPolltarget(get_record(slot)->data, new_poll_target);
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NSR_InitiateSampleBurst(int n_good_samples, int n_total_samples,
+                        IPAddr *mask, IPAddr *address)
+{
+  SourceRecord *record;
+  unsigned int i;
+  int any;
+
+  any = 0;
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (record->remote_addr) {
+      if (address->family == IPADDR_UNSPEC ||
+          !UTI_CompareIPs(&record->remote_addr->ip_addr, address, mask)) {
+        any = 1;
+        NCR_InitiateSampleBurst(record->data, n_good_samples, n_total_samples);
+      }
+    }
+  }
+
+  return any;
+
+}
+
+/* ================================================== */
+/* The ip address is assumed to be completed on input, that is how we
+   identify the source record. */
+
+void
+NSR_ReportSource(RPT_SourceReport *report, struct timespec *now)
+{
+  int slot;
+
+  if (find_slot(&report->ip_addr, &slot)) {
+    NCR_ReportSource(get_record(slot)->data, report, now);
+  } else {
+    report->poll = 0;
+    report->latest_meas_ago = 0;
+  }
+}
+
+/* ================================================== */
+
+int
+NSR_GetAuthReport(IPAddr *address, RPT_AuthReport *report)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_GetAuthReport(get_record(slot)->data, report);
+  return 1;
+}
+
+/* ================================================== */
+/* The ip address is assumed to be completed on input, that is how we
+   identify the source record. */
+
+int
+NSR_GetNTPReport(RPT_NTPReport *report)
+{
+  int slot;
+
+  if (!find_slot(&report->remote_addr, &slot))
+    return 0;
+
+  NCR_GetNTPReport(get_record(slot)->data, report);
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NSR_GetActivityReport(RPT_ActivityReport *report)
+{
+  SourceRecord *record;
+  unsigned int i;
+
+  report->online = 0;
+  report->offline = 0;
+  report->burst_online = 0;
+  report->burst_offline = 0;
+  report->unresolved = 0;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr)
+      continue;
+
+    if (!UTI_IsIPReal(&record->remote_addr->ip_addr)) {
+      report->unresolved++;
+    } else {
+      NCR_IncrementActivityCounters(record->data, &report->online, &report->offline,
+                                    &report->burst_online, &report->burst_offline);
+    }
+  }
+}
+
+/* ================================================== */
+
+void
+NSR_DumpAuthData(void)
+{
+  SourceRecord *record;
+  int i;
+
+  for (i = 0; i < ARR_GetSize(records); i++) {
+    record = get_record(i);
+    if (!record->remote_addr)
+      continue;
+    NCR_DumpAuthData(record->data);
+  }
+}