Clamp every elapsed time span at zero, using a set of helper functions

8 files changed, 40 insertions, 23 deletions

diff --git a/src/opentracker.c b/src/opentracker.c
index 60a6d8c..8de3fc1 100644
--- a/src/opentracker.c
+++ b/src/opentracker.c
@@ -151,7 +151,7 @@ static void *server_mainloop(void *args) {
     while ((sock = workqueue_popresult(&iovec_entries, &iovector, &is_partial)) != -1)
       http_sendiovecdata(sock, &ws, iovec_entries, iovector, is_partial);
 
-    if (time_now_seconds() > next_timeout_check) {
+    if (time_is_past(next_timeout_check)) {
       int cursor = 0;
 
       while ((sock = fdstate_next_expired(time_now_seconds(), &cursor)) != -1)
diff --git a/src/ot_accesslist.c b/src/ot_accesslist.c
index 86f9a7d..ea5bdba 100644
--- a/src/ot_accesslist.c
+++ b/src/ot_accesslist.c
@@ -91,7 +91,7 @@ static ot_accesslist *accesslist_make(ot_accesslist *next, size_t size) {
    This will never delete head, because that might still be in use. */
 static void accesslist_clean(ot_accesslist *accesslist) {
   while (accesslist && accesslist->next) {
-    if (accesslist->next->base + 5 < time_now_minutes())
+    if (time_since_minutes(accesslist->next->base) > 5)
       accesslist->next = accesslist_free(accesslist->next);
     accesslist = accesslist->next;
   }
diff --git a/src/ot_clean.c b/src/ot_clean.c
index f181e83..2ebfd42 100644
--- a/src/ot_clean.c
+++ b/src/ot_clean.c
@@ -45,7 +45,7 @@ static ssize_t clean_single_bucket(ot_peer *peers, size_t peer_count, size_t pee
 
 int clean_single_peer_list(ot_peerlist *peer_list, size_t peer_size) {
   ot_vector *peer_vector = &peer_list->peers;
-  time_t     timedout    = (time_t)(time_now_minutes() - peer_list->base);
+  ot_time    timedout    = time_since_minutes(peer_list->base);
   size_t     num_buckets = 1, removed_seeders = 0;
 
   /* No need to clean empty torrent */
diff --git a/src/ot_http.c b/src/ot_http.c
index 96b8f4e..533a876 100644
--- a/src/ot_http.c
+++ b/src/ot_http.c
@@ -414,7 +414,7 @@ static ssize_t http_handle_fullscrape(const int64_t sock, struct ot_workstruct *
       pthread_mutex_unlock(&g_modest_fullscrape_mutex);
       HTTPERROR_500;
     }
-    if (exactmatch && (this_peer.last_fullscrape - new_peer->last_fullscrape) < OT_MODEST_PEER_TIMEOUT) {
+    if (exactmatch && time_since_seconds(new_peer->last_fullscrape) < OT_MODEST_PEER_TIMEOUT) {
       pthread_mutex_unlock(&g_modest_fullscrape_mutex);
       HTTPERROR_402_NOTMODEST;
     }
diff --git a/src/ot_livesync.c b/src/ot_livesync.c
index 85577f7..7d7208e 100644
--- a/src/ot_livesync.c
+++ b/src/ot_livesync.c
@@ -178,13 +178,13 @@ void livesync_ticker(void) {
 
   /* livesync_issue_peersync sets g_next_packet_time */
   pthread_mutex_lock(&g_outbuf_mutex);
-  if (time_now_seconds() > g_v6_buf.next_packet_time && g_v6_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
+  if (time_is_past(g_v6_buf.next_packet_time) && g_v6_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
     livesync_issue_peersync(&g_v6_buf);
   else
     pthread_mutex_unlock(&g_outbuf_mutex);
 
   pthread_mutex_lock(&g_outbuf_mutex);
-  if (time_now_seconds() > g_v4_buf.next_packet_time && g_v4_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
+  if (time_is_past(g_v4_buf.next_packet_time) && g_v4_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
     livesync_issue_peersync(&g_v4_buf);
   else
     pthread_mutex_unlock(&g_outbuf_mutex);
diff --git a/src/ot_stats.c b/src/ot_stats.c
index 2d6335b..7b5b1b9 100644
--- a/src/ot_stats.c
+++ b/src/ot_stats.c
@@ -373,7 +373,7 @@ void stats_top_txt(char **reply, const char *reply_end, size_t amount) {
 static unsigned long events_per_time(unsigned long long events, time_t t) { return events / ((unsigned int)t ? (unsigned int)t : 1); }
 
 static void        stats_connections_mrtg(char **reply, const char *reply_end) {
-  ot_time t = time(NULL) - ot_start_time;
+  ot_time t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -386,7 +386,7 @@ static void        stats_connections_mrtg(char **reply, const char *reply_end) {
 }
 
 static void stats_udpconnections_mrtg(char **reply, const char *reply_end) {
-  ot_time t = time(NULL) - ot_start_time;
+  ot_time t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -398,7 +398,7 @@ static void stats_udpconnections_mrtg(char **reply, const char *reply_end) {
 }
 
 static void stats_tcpconnections_mrtg(char **reply, const char *reply_end) {
-  time_t t = time(NULL) - ot_start_time;
+  time_t t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -409,7 +409,7 @@ static void stats_tcpconnections_mrtg(char **reply, const char *reply_end) {
 }
 
 static void stats_scrape_mrtg(char **reply, const char *reply_end) {
-  time_t t = time(NULL) - ot_start_time;
+  time_t t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -420,7 +420,7 @@ static void stats_scrape_mrtg(char **reply, const char *reply_end) {
 }
 
 static void stats_fullscrapes_mrtg(char **reply, const char *reply_end) {
-  ot_time t = time(NULL) - ot_start_time;
+  ot_time t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -468,7 +468,7 @@ static void stats_return_renew_bucket(char **reply, const char *reply_end) {
 }
 
 static void stats_return_sync_mrtg(char **reply, const char *reply_end) {
-  ot_time t = time(NULL) - ot_start_time;
+  ot_time t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -479,7 +479,7 @@ static void stats_return_sync_mrtg(char **reply, const char *reply_end) {
 }
 
 static void stats_return_completed_mrtg(char **reply, const char *reply_end) {
-  ot_time t = time(NULL) - ot_start_time;
+  ot_time t = time_since_seconds(ot_start_time);
   unsigned long long total[OT_COUNTER_COUNT];
 
   counters_total(total);
@@ -510,7 +510,7 @@ static void stats_return_everything(char **reply, const char *reply_end) {
 
   fmt_append(reply, reply_end, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
   fmt_append(reply, reply_end, "<stats>\n");
-  fmt_append(reply, reply_end, "  <uptime>%llu</uptime>\n", (unsigned long long)(time(NULL) - ot_start_time));
+  fmt_append(reply, reply_end, "  <uptime>%llu</uptime>\n", (unsigned long long)time_since_seconds(ot_start_time));
   fmt_append(reply, reply_end, "  <torrents>\n");
   fmt_append(reply, reply_end, "    <count_mutex>%zd</count_mutex>\n", mutex_get_torrent_count());
   fmt_append(reply, reply_end, "    <count_iterator>%llu</count_iterator>\n", stats.torrent_count);
@@ -785,7 +785,7 @@ void stats_issue_event(struct ot_workstruct *ws, ot_status_event event, PROTO_FL
   case EVENT_FULLSCRAPE_REQUEST: {
     ot_ip6 *ip = (ot_ip6 *)event_data; /* ugly hack to transfer ip to stats */
     char    _debug[512];
-    int     off  = snprintf(_debug, sizeof(_debug), "[%08d] scrp:  ", (unsigned int)(time_now_seconds() - ot_start_time) / 60);
+    int     off  = snprintf(_debug, sizeof(_debug), "[%08d] scrp:  ", (unsigned int)time_since_seconds(ot_start_time) / 60);
     off         += ip_format(_debug + off, *ip);
     off         += snprintf(_debug + off, sizeof(_debug) - off, " - FULL SCRAPE\n");
     (void)write(2, _debug, off);
@@ -794,7 +794,7 @@ void stats_issue_event(struct ot_workstruct *ws, ot_status_event event, PROTO_FL
   case EVENT_FULLSCRAPE_REQUEST_GZIP: {
     ot_ip6 *ip = (ot_ip6 *)event_data; /* ugly hack to transfer ip to stats */
     char    _debug[512];
-    int     off  = snprintf(_debug, sizeof(_debug), "[%08d] scrp:  ", (unsigned int)(time_now_seconds() - ot_start_time) / 60);
+    int     off  = snprintf(_debug, sizeof(_debug), "[%08d] scrp:  ", (unsigned int)time_since_seconds(ot_start_time) / 60);
     off         += ip_format(_debug + off, *ip);
     off         += snprintf(_debug + off, sizeof(_debug) - off, " - FULL SCRAPE\n");
     (void)write(2, _debug, off);
@@ -804,7 +804,8 @@ void stats_issue_event(struct ot_workstruct *ws, ot_status_event event, PROTO_FL
     COUNT(OT_COUNTER_FAILED + event_data, 1);
     break;
   case EVENT_RENEW:
-    COUNT(OT_COUNTER_RENEWED + event_data, 1);
+    if (event_data < OT_PEER_TIMEOUT)
+      COUNT(OT_COUNTER_RENEWED + event_data, 1);
     break;
   case EVENT_SYNC:
     COUNT(OT_COUNTER_SYNCS, event_data);
diff --git a/src/ot_udp.c b/src/ot_udp.c
index 644b71d..e67ca1f 100644
--- a/src/ot_udp.c
+++ b/src/ot_udp.c
@@ -39,12 +39,12 @@ static void udp_make_connectionid(uint32_t connid[2], const ot_ip6 remoteip, int
   int      i;
   uint32_t current_key_of_the_hour;
 
-  if (time_now_minutes() - g_hour_of_the_key >= 60) {
+  if (time_since_minutes(g_hour_of_the_key) >= 60) {
     uint32_t old_key_of_the_hour = g_key_of_the_hour[0];
     uint32_t new_key_of_the_hour = random_uint32();
     /* If in the meantime another thread has performed
        key rotation, do not overwrite their results */
-    if (time_now_minutes() - g_hour_of_the_key >= 60) {
+    if (time_since_minutes(g_hour_of_the_key) >= 60) {
       /* Upgrade en bloc */
       g_hour_of_the_key    = time_now_minutes();
       g_key_of_the_hour[0] = new_key_of_the_hour;
diff --git a/src/trackerlogic.h b/src/trackerlogic.h
index 692b6af..c8d859c 100644
--- a/src/trackerlogic.h
+++ b/src/trackerlogic.h
@@ -61,10 +61,10 @@ typedef struct {
 #define OT_PEER_TIMEOUT               45
 
 /* We maintain a list of 1024 pointers to sorted list of ot_torrent structs
- Sort key is, of course, its hash */
-/* Set from the Makefile, 8 to 16. More buckets means shorter vectors and a
-   cheaper insert, which only pays for a tracker carrying millions of
-   torrents; see DESIGN. */
+ Sort key is, of course, its hash.
+ Can be tweked from the Makefile, sensible values are between 8 in 16. More
+ buckets means shorter vectors and a cheaper insert, which only pays for a
+ tracker carrying millions of torrents. Consult the DESIGN document. */
 #ifndef OT_BUCKET_COUNT_BITS
 #define OT_BUCKET_COUNT_BITS          10
 #endif
@@ -95,6 +95,22 @@ static inline ot_time time_now_minutes(void) { return time_now_seconds() / 60; }
 /* For the deadlines the tracker sets on itself, which read better as the
    span they allow than as an addition to the current second */
 static inline ot_time time_future_seconds(int span) { return time_now_seconds() + span; }
+
+/* How long ago a stamp was taken. */
+_Static_assert((ot_time)-1 < 0, "ot_time has to be signed for time_since_* to clamp");
+
+static inline ot_time time_since_seconds(ot_time then) {
+  ot_time now = time_now_seconds();
+  return now > then ? now - then : 0;
+}
+
+static inline ot_time time_since_minutes(ot_time then) {
+  ot_time now = time_now_minutes();
+  return now > then ? now - then : 0;
+}
+
+/* Has a deadline the tracker set on itself gone by? */
+static inline int time_is_past(ot_time deadline) { return time_now_seconds() > deadline; }
 /* Cleared from the interrupt handler and read by every worker */
 extern _Atomic int    g_opentracker_running;