- Introducing millisecond resolution support for the timeout option. See

  ares_init_options()'s ARES_OPT_TIMEOUTMS.

1 files changed, 93 insertions, 39 deletions

diff --git a/ares_process.c b/ares_process.c
index 442e328..eca363a 100644
--- a/ares_process.c
+++ b/ares_process.c
@@ -1,6 +1,7 @@
 /* $Id$ */
 
 /* Copyright 1998 by the Massachusetts Institute of Technology.
+ * Copyright (C) 2004-2008 by Daniel Stenberg
  *
  * Permission to use, copy, modify, and distribute this
  * software and its documentation for any purpose and without
@@ -42,6 +43,9 @@
 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
 #include <arpa/nameser_compat.h>
 #endif
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
 #endif /* WIN32 && !WATT32 */
 
 #ifdef HAVE_STRINGS_H
@@ -71,21 +75,25 @@
 
 static int try_again(int errnum);
 static void write_tcp_data(ares_channel channel, fd_set *write_fds,
-                           ares_socket_t write_fd, time_t now);
+                           ares_socket_t write_fd, struct timeval *now);
 static void read_tcp_data(ares_channel channel, fd_set *read_fds,
-                          ares_socket_t read_fd, time_t now);
+                          ares_socket_t read_fd, struct timeval *now);
 static void read_udp_packets(ares_channel channel, fd_set *read_fds,
-                             ares_socket_t read_fd, time_t now);
+                             ares_socket_t read_fd, struct timeval *now);
 static void advance_tcp_send_queue(ares_channel channel, int whichserver,
                                    ssize_t num_bytes);
-static void process_timeouts(ares_channel channel, time_t now);
-static void process_broken_connections(ares_channel channel, time_t now);
+static void process_timeouts(ares_channel channel, struct timeval *now);
+static void process_broken_connections(ares_channel channel,
+                                       struct timeval *now);
 static void process_answer(ares_channel channel, unsigned char *abuf,
-                           int alen, int whichserver, int tcp, time_t now);
-static void handle_error(ares_channel channel, int whichserver, time_t now);
+                           int alen, int whichserver, int tcp,
+                           struct timeval *now);
+static void handle_error(ares_channel channel, int whichserver,
+                         struct timeval *now);
 static void skip_server(ares_channel channel, struct query *query,
                         int whichserver);
-static void next_server(ares_channel channel, struct query *query, time_t now);
+static void next_server(ares_channel channel, struct query *query,
+                        struct timeval *now);
 static int configure_socket(int s, ares_channel channel);
 static int open_tcp_socket(ares_channel channel, struct server_state *server);
 static int open_udp_socket(ares_channel channel, struct server_state *server);
@@ -94,19 +102,59 @@ static int same_questions(const unsigned char *qbuf, int qlen,
 static void end_query(ares_channel channel, struct query *query, int status,
                       unsigned char *abuf, int alen);
 
+/* return true if now is exactly check time or later */
+int ares__timedout(struct timeval *now,
+                   struct timeval *check)
+{
+  int secs = (now->tv_sec - check->tv_sec);
+
+  if(secs > 0)
+    return 1; /* yes, timed out */
+  if(secs < -1)
+    return 0; /* nope, not timed out */
+
+  /* if the full seconds were identical, check the sub second parts */
+  return (now->tv_usec - check->tv_usec >= 0);
+}
+
+/* add the specific number of milliseconds to the time in the first argument */
+int ares__timeadd(struct timeval *now,
+                  int millisecs)
+{
+  now->tv_sec += millisecs/1000;
+  now->tv_usec += (millisecs%1000)*1000;
+
+  if(now->tv_usec >= 1000000) {
+    ++(now->tv_sec);
+    now->tv_usec -= 1000000;
+  }
+
+  return 0;
+}
+
+/* return time offset between now and (future) check, in milliseconds */
+int ares__timeoffset(struct timeval *now,
+                     struct timeval *check)
+{
+  int secs = (check->tv_sec - now->tv_sec); /* this many seconds */
+  int us = (check->tv_usec - now->tv_usec); /* this many microseconds */
+
+  return secs*1000 + us/1000; /* return them combined as milliseconds */
+}
+
+
 /* Something interesting happened on the wire, or there was a timeout.
  * See what's up and respond accordingly.
  */
 void ares_process(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
 {
-  time_t now;
-
-  time(&now);
-  write_tcp_data(channel, write_fds, ARES_SOCKET_BAD, now);
-  read_tcp_data(channel, read_fds, ARES_SOCKET_BAD, now);
-  read_udp_packets(channel, read_fds, ARES_SOCKET_BAD, now);
-  process_timeouts(channel, now);
-  process_broken_connections(channel, now);
+  struct timeval now = ares__tvnow();
+
+  write_tcp_data(channel, write_fds, ARES_SOCKET_BAD, &now);
+  read_tcp_data(channel, read_fds, ARES_SOCKET_BAD, &now);
+  read_udp_packets(channel, read_fds, ARES_SOCKET_BAD, &now);
+  process_timeouts(channel, &now);
+  process_broken_connections(channel, &now);
 }
 
 /* Something interesting happened on the wire, or there was a timeout.
@@ -117,13 +165,12 @@ void ares_process_fd(ares_channel channel,
                                                file descriptors */
                      ares_socket_t write_fd)
 {
-  time_t now;
+  struct timeval now = ares__tvnow();
 
-  time(&now);
-  write_tcp_data(channel, NULL, write_fd, now);
-  read_tcp_data(channel, NULL, read_fd, now);
-  read_udp_packets(channel, NULL, read_fd, now);
-  process_timeouts(channel, now);
+  write_tcp_data(channel, NULL, write_fd, &now);
+  read_tcp_data(channel, NULL, read_fd, &now);
+  read_udp_packets(channel, NULL, read_fd, &now);
+  process_timeouts(channel, &now);
 }
 
 
@@ -158,7 +205,7 @@ static int try_again(int errnum)
 static void write_tcp_data(ares_channel channel,
                            fd_set *write_fds,
                            ares_socket_t write_fd,
-                           time_t now)
+                           struct timeval *now)
 {
   struct server_state *server;
   struct send_request *sendreq;
@@ -177,7 +224,8 @@ static void write_tcp_data(ares_channel channel,
       /* Make sure server has data to send and is selected in write_fds or
          write_fd. */
       server = &channel->servers[i];
-      if (!server->qhead || server->tcp_socket == ARES_SOCKET_BAD || server->is_broken)
+      if (!server->qhead || server->tcp_socket == ARES_SOCKET_BAD ||
+          server->is_broken)
         continue;
 
       if(write_fds) {
@@ -281,7 +329,7 @@ static void advance_tcp_send_queue(ares_channel channel, int whichserver,
  * a packet if we finish reading one.
  */
 static void read_tcp_data(ares_channel channel, fd_set *read_fds,
-                          ares_socket_t read_fd, time_t now)
+                          ares_socket_t read_fd, struct timeval *now)
 {
   struct server_state *server;
   int i;
@@ -377,7 +425,7 @@ static void read_tcp_data(ares_channel channel, fd_set *read_fds,
 
 /* If any UDP sockets select true for reading, process them. */
 static void read_udp_packets(ares_channel channel, fd_set *read_fds,
-                             ares_socket_t read_fd, time_t now)
+                             ares_socket_t read_fd, struct timeval *now)
 {
   struct server_state *server;
   int i;
@@ -428,7 +476,7 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
 }
 
 /* If any queries have timed out, note the timeout and move them on. */
-static void process_timeouts(ares_channel channel, time_t now)
+static void process_timeouts(ares_channel channel, struct timeval *now)
 {
   time_t t;  /* the time of the timeouts we're processing */
   struct query *query;
@@ -441,14 +489,14 @@ static void process_timeouts(ares_channel channel, time_t now)
    * only a handful of requests that fall into the "now" bucket, so
    * this should be quite quick.
    */
-  for (t = channel->last_timeout_processed; t <= now; t++)
+  for (t = channel->last_timeout_processed; t <= now->tv_sec; t++)
     {
       list_head = &(channel->queries_by_timeout[t % ARES_TIMEOUT_TABLE_SIZE]);
       for (list_node = list_head->next; list_node != list_head; )
         {
           query = list_node->data;
           list_node = list_node->next;  /* in case the query gets deleted */
-          if (query->timeout != 0 && now >= query->timeout)
+          if (query->timeout.tv_sec && ares__timedout(now, &query->timeout))
             {
               query->error_status = ARES_ETIMEOUT;
               ++query->timeouts;
@@ -456,12 +504,13 @@ static void process_timeouts(ares_channel channel, time_t now)
             }
         }
      }
-  channel->last_timeout_processed = now;
+  channel->last_timeout_processed = now->tv_sec;
 }
 
 /* Handle an answer from a server. */
 static void process_answer(ares_channel channel, unsigned char *abuf,
-                           int alen, int whichserver, int tcp, time_t now)
+                           int alen, int whichserver, int tcp,
+                           struct timeval *now)
 {
   int tc, rcode;
   unsigned short id;
@@ -539,7 +588,8 @@ static void process_answer(ares_channel channel, unsigned char *abuf,
 }
 
 /* Close all the connections that are no longer usable. */
-static void process_broken_connections(ares_channel channel, time_t now)
+static void process_broken_connections(ares_channel channel,
+                                       struct timeval *now)
 {
   int i;
   for (i = 0; i < channel->nservers; i++)
@@ -552,7 +602,8 @@ static void process_broken_connections(ares_channel channel, time_t now)
     }
 }
 
-static void handle_error(ares_channel channel, int whichserver, time_t now)
+static void handle_error(ares_channel channel, int whichserver,
+                         struct timeval *now)
 {
   struct server_state *server;
   struct query *query;
@@ -603,7 +654,8 @@ static void skip_server(ares_channel channel, struct query *query,
     }
 }
 
-static void next_server(ares_channel channel, struct query *query, time_t now)
+static void next_server(ares_channel channel, struct query *query,
+                        struct timeval *now)
 {
   /* Advance to the next server or try. */
   query->server++;
@@ -640,7 +692,8 @@ static void next_server(ares_channel channel, struct query *query, time_t now)
   end_query(channel, query, query->error_status, NULL, 0);
 }
 
-void ares__send_query(ares_channel channel, struct query *query, time_t now)
+void ares__send_query(ares_channel channel, struct query *query,
+                      struct timeval *now)
 {
   struct send_request *sendreq;
   struct server_state *server;
@@ -707,16 +760,17 @@ void ares__send_query(ares_channel channel, struct query *query, time_t now)
           return;
         }
     }
-    query->timeout = now
-        + ((query->try == 0) ? channel->timeout
-           : channel->timeout << query->try / channel->nservers);
+    query->timeout = *now;
+    ares__timeadd(&query->timeout,
+                  (query->try == 0) ? channel->timeout
+                  : channel->timeout << query->try / channel->nservers);
     /* Keep track of queries bucketed by timeout, so we can process
      * timeout events quickly.
      */
     ares__remove_from_list(&(query->queries_by_timeout));
     ares__insert_in_list(
         &(query->queries_by_timeout),
-        &(channel->queries_by_timeout[query->timeout %
+        &(channel->queries_by_timeout[query->timeout.tv_sec %
                                       ARES_TIMEOUT_TABLE_SIZE]));
 
     /* Keep track of queries bucketed by server, so we can process server