Use roughly throughout.

This very slightly reduces the amount of jitter in some cases.

babel.c

@@ -512,17 +512,17 @@ main(int argc, char **argv)
     kernel_routes_changed = 0;
     kernel_link_changed = 0;
     kernel_addr_changed = 0;
-    kernel_dump_time = now.tv_sec + 20 + random() % 20;
+    kernel_dump_time = now.tv_sec + roughly(30);
     schedule_neighbours_check(5000, 1);
-    expiry_time = now.tv_sec + 20 + random() % 20;
-    source_expiry_time = now.tv_sec + 200 + random() % 200;
+    expiry_time = now.tv_sec + roughly(30);
+    source_expiry_time = now.tv_sec + roughly(300);
 
     /* Make some noise so that others notice us */
     FOR_ALL_NETS(net) {
         if(!net->up)
             continue;
         /* Apply jitter before we send the first message. */
-        usleep(5000 + random() % 10000);
+        usleep(roughly(10000));
         gettime(&now);
         send_hello(net);
         send_self_update(net, 0);
@@ -631,9 +631,9 @@ main(int argc, char **argv)
                 fprintf(stderr, "Warning: couldn't check exported routes.\n");
             kernel_routes_changed = kernel_addr_changed = 0;
             if(kernel_socket >= 0)
-                kernel_dump_time = now.tv_sec + 200 + random() % 200;
+                kernel_dump_time = now.tv_sec + roughly(300);
             else
-                kernel_dump_time = now.tv_sec + 20 + random() % 20;
+                kernel_dump_time = now.tv_sec + roughly(30);
         }
 
         if(timeval_compare(&check_neighbours_timeout, &now) < 0) {
@@ -647,12 +647,12 @@ main(int argc, char **argv)
             check_networks();
             expire_routes();
             expire_resend();
-            expiry_time = now.tv_sec + 20 + random() % 20;
+            expiry_time = now.tv_sec + roughly(30);
         }
 
         if(now.tv_sec >= source_expiry_time) {
             expire_sources();
-            source_expiry_time = now.tv_sec + 200 + random() % 200;
+            source_expiry_time = now.tv_sec + roughly(300);
         }
 
         FOR_ALL_NETS(net) {
@@ -699,7 +699,7 @@ main(int argc, char **argv)
     }
 
     debugf("Exiting...\n");
-    usleep(5000 + random() % 10000);
+    usleep(roughly(10000));
     gettime(&now);
 
     /* Uninstall and retract all routes. */
@@ -726,7 +726,7 @@ main(int argc, char **argv)
            association caches. */
         send_hello_noupdate(net, 10);
         flushbuf(net);
-        usleep(500 + random() % 1000);
+        usleep(roughly(1000));
         gettime(&now);
     }
     FOR_ALL_NETS(net) {
@@ -735,7 +735,7 @@ main(int argc, char **argv)
         /* Make sure they got it. */
         send_hello_noupdate(net, 1);
         flushbuf(net);
-        usleep(5000 + random() % 10000);
+        usleep(roughly(10000));
         gettime(&now);
         network_up(net, 0);
     }
@@ -808,7 +808,7 @@ schedule_neighbours_check(int msecs, int override)
 {
     struct timeval timeout;
 
-    timeval_plus_msec(&timeout, &now, msecs + random() % msecs);
+    timeval_plus_msec(&timeout, &now, roughly(msecs * 3 / 2));
     if(override)
         check_neighbours_timeout = timeout;
     else

message.c

@@ -413,7 +413,7 @@ void
 schedule_flush_now(struct network *net)
 {
     /* Almost now */
-    int msecs = 5 + random() % 10;
+    int msecs = roughly(10);
     if(net->flush_timeout.tv_sec != 0 &&
        timeval_minus_msec(&net->flush_timeout, &now) < msecs)
         return;

network.c

@@ -127,8 +127,8 @@ jitter(struct network *net, int urgent)
     if(urgent)
         interval = MIN(interval, 100);
     else
-        interval = MIN(interval, 2000);
-    return (interval / 2 + random() % interval) / 4;
+        interval = MIN(interval, 4000);
+    return roughly(interval) / 4;
 }
 
 unsigned int
@@ -139,17 +139,14 @@ update_jitter(struct network *net, int urgent)
         interval = MIN(interval, 100);
     else
         interval = MIN(interval, 4000);
-    return (interval / 2 + random() % interval);
+    return roughly(interval);
 }
 
 void
 delay_jitter(struct timeval *time, struct timeval *timeout, int msecs)
 {
-    int delay;
-    delay = msecs * 2 / 3 + random() % (msecs * 2 / 3);
-
     *time = now;
-    timeval_plus_msec(timeout, &now, delay);
+    timeval_plus_msec(timeout, &now, roughly(msecs));
 }
 
 static int